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  • 1995-1999  (955)
  • 1999  (955)
  • General Chemistry  (750)
  • apoptosis  (112)
  • Apoptosis  (93)
  • Atomic, Molecular and Optical Physics
  • Inorganic Chemistry
  • Nuclear reactions
Material
Years
  • 1995-1999  (955)
Year
Keywords
  • 1
    ISSN: 1534-4681
    Keywords: Gemcitabine ; bcl-2 ; Pancreatic cancer ; Apoptosis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Background: Gemcitabine is a new nucleoside analogue that produces a clinical response in 30% of patients with unresectable pancreatic carcinoma. The cytotoxic effects of many chemotherapeutic agents occur through induction of programmed cell death (apoptosis), which is controlled by the bcl-2 gene family. We determined whether induction of apoptosis by gemcitabine in pancreatic carcinoma is associated with cellular Bcl-2 content. Methods: Four pancreatic carcinoma cell lines (MIA-PaCa-2, AsPC-1, Panc-1, and Panc-48) were screened by Western blotting for Bcl-2 protein expression. Dose-response relationships for the cytotoxic effects of gemcitabine were determined using methylthiotetrazole assays, and induction of apoptosis was confirmed by fluorescence-activated cell sorting analysis. MIA-PaCa-2 cells transfected with human bcl-2 were also analyzed for gemcitabine-induced apoptosis. Results: Pancreatic cancer cell lines expressed varying amounts of Bcl-2, and the 50% lethal dose for gemcitabine-induced apoptosis was correlated with Bcl-2 content. Furthermore, Bcl-2 overexpression was associated with a significant increase in the 50% lethal dose for gemcitabine-induced apoptosis. Conclusions: Cellular Bcl-2 content was directly correlated with the cytotoxicity of gemcitabine in pancreatic carcinoma. Therefore, routine immunohistochemical analyses may be useful in predicting gemcitabine efficacy, and patients who would likely not benefit could be spared gemcitabine administration. Furthermore, the effectiveness of gemcitabine and other chemotherapeutic agents may be increased by gene therapy-mediated alteration of bcl-2 gene family members.
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  • 2
    ISSN: 1436-2813
    Keywords: thyroid tumor ; apoptosis ; TUNEL ; MIB-1
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract To clarify the growth mechanisms of thyroid tumors, we examined apoptotic cells in 61 thyroid tumors, consiting of 14 adenomas, 35 papillary carcinomas, 4 follicular carcinomas, and 8 undifferentiated carcinomas, using terminal deoxynucleotidyl transferase mediated deoxyuridine triphosphate digoxigenin-nick end labeling (TUNEL). The proliferative activity was also evaluated immunohistochemically using the monoclonal antibody to Ki-67 antigen (MIB-1) in the same tumors. The apoptotic index (AI) was expressed as a percentage of the TUNEL-positive cells in the tumor cells, and a proliferation index (PI), being the percentage of Ki-67 positive cells, was calculated for each tumor. The overall level of AI was very low in all histotypes of the thyroid tumors analyzed, the mean AI being 0.5±0.4 in adenoma, 0.4±0.3 in differentiated carcinoma, and 1.8±1.5 in undifferentiated carcinoma. The PI in the thyroid tumor subtypes was significantly lower in adenoma and differentiated carcinoma, at 0.5 ±0.7 and 1.1±0.7, respectively, than that in undifferentiated carcinoma at 14.5±3.7 (P〈0.05). There was no correlation between clinicopathological factors and AI or PI in differentiated thyroid carcinoma. Our findings suggest that apoptosis occurs infrequently in thyroid tumors, and that proliferative activity markedly differs according to the thyroid tumor subtypes. Moreover, the ratio between proliferating cells and apoptotic cells may reflect thyroid tumor progression.
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  • 3
    ISSN: 1436-2813
    Keywords: Key Words: thyroid tumor ; apoptosis ; TUNEL ; MIB-1
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: P 〈 0.05). There was no correlation between clinicopathological factors and AI or PI in differentiated thyroid carcinoma. Our findings suggest that apoptosis occurs infrequently in thyroid tumors, and that proliferative activity markedly differs according to the thyroid tumor subtypes. Moreover, the ratio between proliferating cells and apoptotic cells may reflect thyroid tumor progression.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Springer
    Journal of neural transmission 106 (1999), S. 1-21 
    ISSN: 1435-1463
    Keywords: Keywords: Paraquat ; Parkinson's disease ; transcription factor ; AP-1 ; apoptosis ; cycloheximide ; genistein ; SOD ; catalase ; oxidative stress.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary. Drugs and certain environmental toxins may be responsible for the pathogenesis of Parkinson's disease. We have used paraquat as a model toxin for this study since paraquat has been shown to make its way to the nerve terminals and cause cell death of dopamine neurons by oxidative injury. We have shown by the electrophoretic mobility shift assay that paraquat, together with low concentrations of chelated iron (Fe++/DETAPAC), induced the activation of transcription factor AP-1 binding activity to DNA. Under similar conditions we also found by both a DNA laddering assay procedure and by terminal deoxynucleotidyl transferase assay (TUNEL assay) that paraquat also induces apoptotic cell death. Interestingly, both apoptotic cell death and AP-1/DNA binding activity induced by paraquat were blocked by cyclohexamide and genistein, indicating that both the AP-1/DNA binding activation and apoptosis induced by paraquat are closely related. Moreover, cells were also protected from paraquat toxicity in the presence of antioxidant defense enzymes SOD and catalase. The results support the hypothesis that oxidative stress may be contributing to the apoptotic cell death of dopaminergic neurons, leading to the manifestation of Parkinson's disease. Since paraquat was an important herbicide in the mid 20th Century, our results have the important implication that exposure to environmental toxins such as paraquat may induce Parkinson's disease.
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  • 5
    ISSN: 1572-8773
    Keywords: cadmium ; apoptosis ; RT-PCR ; p53 gene expression ; testes ; rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Reverse transcription (RT) PCR technique was used to investigate the mechanism of apoptosis induced by Cd and the change of its related genes in testes and prostate of rats. Adult male rats were given a single (s.c.) injection of CdC l2 0, 2.5, 5.0, 10 μmol/kg. 48 h and 72 h after administration of Cd, animals were sacrificed. The results indicated that Cd can induce apoptosis in testes via p53-independent pathway. No apoptosis occurred in prostate in any of the Cd-exposed groups. There was a clearly negative relationship in testes between p53 gene expression and Cd exposure and this dose-response relationship was observed both at 48 h and 72 h. There was a very small increase of this gene expression in the dorsolateral lobe of the prostate in Cd exposed groups. The other apoptosis related gene, bcl-x, was not detectable in either control or Cd-exposed group in testes and dorsal prostate. Although the MT-I gene was expressed in testes or dorsal prostate both in control and exposed groups, no overexpression of MT-I gene was found after administration of Cd . The expression of MT-I in the ventral prostate was not detected in the control group, but a weak expression was found after Cd exposure. Since p53 is a tumo r suppressor gene which can inhibit tumorigenesis, the consequence of a Cd-induced decrease of p53 in testes may have a relation to the known risk of Cd tumorigenesis in this tissue.
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  • 6
    ISSN: 1569-8041
    Keywords: AML ; apoptosis ; etoposide ; γ-GCS ; glutathione ; oxidative stress
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Background: Etoposide mediates its cytotoxicity by inducing apoptosis. Thus, mechanisms which regulate apoptosis should also affect drug resistance. Oxidants and antioxidants have been shown to participate in the regulation of apoptosis. We were interested in studying whether responsiveness of acute myeloblastic leukemia (AML) cells to etoposide is mediated by oxidative stress and glutathione levels. Patients and methods: Two subclones of the OCI/AML-2 cell line which are etoposide-sensitive (ES), and etoposide-resistant (ER), were established by the authors at the University of Oulu, and used as models. Assays for apoptosis included externalization of phosphatidylserine (as evidenced by annexin V binding), and caspase activation as indicated by cleavage of poly(ADP-ribose)polymerase (Western blotting). Peroxide formation was analyzed by flow cytometry. Glutathione and gamma-glutamylcysteine synthetase (γ-GCS) levels were determined spectrophotometrically and by Western blotting, respectively. Results: Etoposide-induced apoptosis was evident 12 hours after treatment in the ES subclone, but was apparent in the ER subclone only after 24 hours. The basal glutathione and γ-GCS levels were higher in the ER than the ES subclone. Etoposide increased peroxide formation in both subclones after 12-hour exposure. Significant depletion of glutathione was observed in the ES subclone during etoposide exposure, while glutathione levels were maintained in the ER subclone. In neither of the subclones was induction of γ-GCS observed during 24-hour exposure to etoposide. Furthermore, the catalytic subunit of γ-GCS was cleaved during apoptosis, concurrent with depletion of intracellular glutathione. When glutathione was depleted by treatment with buthionine sulfoximine, a direct inhibitor of γ-GCS, the sensitivity to etoposide was increased, particularly in the ER subclone. Conclusions: The results underline the significance of glutathione biosynthesis in the responsiveness of AML cells to etoposide. The molecular mechanisms mediating glutathione depletion during etoposide exposure might include the cleavage of the catalytic subunit of γ-GCS.
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  • 7
    Electronic Resource
    Electronic Resource
    Springer
    Annals of oncology 10 (1999), S. 495-503 
    ISSN: 1569-8041
    Keywords: antisense ; apoptosis ; bcl-2 ; lymphoma ; leukaemia ; phase I
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    Springer
    Annals of oncology 10 (1999), S. 1011-1021 
    ISSN: 1569-8041
    Keywords: apoptosis ; chemosensitivity ; cytotoxicity ; p53
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Background: Although hematologic malignancies and some solid tumors such as germ cell tumors and pediatric malignancies can be cured by cytotoxic treatment, the most prevalent solid tumors are relatively resistant to these interventions. Apoptosis is involved in the cell kill of anticancer drugs and p53 is believed to be of principal importance in this process. However p53 also plays a role in cell cycle arrest and DNA repair, cellular processes that can decrease the sensitivity to chemotherapy. Therefore, p53 may play a dual role after exposure to cytotoxic treatment, activating either mechanisms that lead to apoptosis or launching processes directing to DNA repair and survival of the cell. Design: In this article, we review in details the p53functions involved in the mediation of chemosensitivity. The preclinical and clinical data published in the recent years about the relation between p53 and chemosensitivity are discussed and the potential pitfalls associated to most of these studies, and that may account for the contradictory results produced so far are also mentioned.
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  • 9
    Electronic Resource
    Electronic Resource
    Springer
    Annals of oncology 10 (1999), S. 31-38 
    ISSN: 1569-8041
    Keywords: apoptosis ; lanreotide treatment ; neuroendocrine gastrointestinal tumors ; octreotide ; somatostatin analogs
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Neuroendocrine gastrointestinal tumors express somatostatin receptors (ssts) in 80%–90% of cases and somatostatin analogs have become increasingly important in the management of these patients. Most of the presently available somatostatin analogs (octreotide, RC-160, and lanreotide) bind to the sst2 and sst5, and in higher doses to sst3 of the ssts 1–5 described. Clinical improvement during somatostatin analog therapy is mainly mediated via a direct inhibitory effect on hormone production from the tumors, seen in 30%–70% of the patients. Also indirect non-tumor mediated effects on peripheral target organs contribute to the subjective improvement, achieved in 30%–70% of patients. Recently, significant improvement of quality of life has been demonstrated with long-acting depot formulations. There is little or no effect on tumor growth during octreotide therapy; tumor shrinkage has been reported in 10%–20% of patients, but stabilization of tumor growth can be achieved in about half of the patients with a duration of 8–16 months. Recently, induction of apoptosis has been described with high doses of lanreotide (12 mg/d). Eventually, however, all patients escape from somatostatin analog therapy with regard both to hormonal production and tumor growth, and the mechanism behind the tachyphylaxis is not yet known. Studies of optimal dosage and modes of administration, development of new slow release formulations, the potential value of high-dose somatostatin analog therapy and novel somatostatin receptor subtype specific analogs are important directions for the use of somatostatin analogs in the future. In addition, assessment of somatostatin receptor status for each patient and studies of tumor biology, e.g., inhibition of exocytosis, antiproliferative effects and induction of apoptosis during treatment will help to optimize treatment and provide new insights into mechanisms of action of somatostatin analogs.
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  • 10
    Electronic Resource
    Electronic Resource
    Springer
    Journal of molecular medicine 77 (1999), S. 189-192 
    ISSN: 1432-1440
    Keywords: Key words Thyroid ; Cell culture ; Retinoids ; Apoptosis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Retinoids influence proliferation and differentiation in transformed thyroid cell lines. Retinoids are able to damage cells by destabilizing lysosomal membranes and induce apoptosis in certain cell lines. In normal thyrocytes retinol modulates iodine metabolism. At concentrations higher than 50×10–6 M retinoids are cytotoxic for normal (not transformed) thyroid cells. The mechanism of this cytotoxicity is unknown. We studied the effect of 7–80×10–6 M retinol on porcine follicular thyrocytes in culture. In order to differentiate between membrane-destabilizing effects and apoptosis we investigated cultures after incubation with retinol by light- and electron-microscopy and by labeling of potential nicks in the DNA helix by terminal deoxynucleotidyltransferase-dUTP mediated DNA nick end labeling. We conclude that the observed cytotoxicity is caused mainly by the induction of apoptosis.
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  • 11
    ISSN: 1432-1440
    Keywords: Key words Chronic lymphocytic leukemia ; Apoptosis ; Cell growth ; Signaling ; Review
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Chronic lymphocytic leukemia is a malignant disease characterized by clonal expansion of relatively mature B-lymphocytes with a high percentage of cells arrested in the nonproliferative G0/G1 cell cycle phase. Possibly reflecting the clinical heterogeneity observed in patients, various signaling pathways may become affected during the initiation and course of this disease. This review discusses frequent alterations concerning proliferative, differentiation-inducing, and apoptotic pathways elucidated in the recent years that have improved our understanding of this disease.
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  • 12
    Electronic Resource
    Electronic Resource
    Springer
    Journal of cancer research and clinical oncology 125 (1999), S. 1-8 
    ISSN: 1432-1335
    Keywords: Key words Cell proliferation ; Apoptosis ; Cell death ; Cultured cells ; Hepatocellular carcinoma
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract There are conflicting results for experiments aimed at determining whether anticancer drug therapy of human hepatocellular carcinoma prolongs the survival rate effectively. The purpose of this study was to assess the effect of low concentrations of doxorubicin, mitomycin C, and ethanol on cell replication (cell number and proliferation), and cell apoptosis of cultured human hepatocellular carcinoma (Hep-G2) cells. After 1 day of exposure doxorubicin inhibited cell replication initially by 72%, but a partial recovery of the cell number was observed. Mitomycin C inhibited to the same extent but without recovery. Ethanol reduced the cell number even further, the maximum inhibition (12 days after exposure) being 96.4%. After 3 days of exposure all three agents stopped cell replication at a level of 2%–4% of the control (P 〈 0.001). Cell apoptosis was activated most strikingly by mitomycin C (5 μg/ml) after 1 day of exposure and by ethanol (150 μl/ml) after 3 days of exposure. Two-way repeated-measures analysis of variance showed statistically significant differences, with ethanol being the most significant followed by mitomycin C doxorubicin, and the control (P 〈 0.01). Thus, a low dose of ethanol combined with an exposure time of up to 3 days appears to be an effective regimen to control growth of human hepatocellular carcinoma cells in vitro. The strong induction of apoptosis by ethanol might be of additional benefit for a local application in vivo.
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  • 13
    ISSN: 1432-1335
    Keywords: Key words Basic fibroblast growth factor ; Cisplatinum ; Apoptosis ; Bcl-2 ; MCF-7
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Basic fibroblast growth factor (bFGF) is a classical mitogen in fibroblasts and endothelial cells. Our previous studies have demonstrated that bFGF inhibits the growth of MCF-7 human breast cancer cells. The aim of the present study was to examine the effect of bFGF on cis-diamminedichloroplatinum(cisplatin)-induced cytotoxicity in MCF-7 breast cancer cells as compared to normal endothelial cells. MCF-7/NCF cells transduced with a vector expressing the bFGF gene and overexpressing its product, and MCF-7/N2 cells transduced with the backbone vector were incubated with a combination of bFGF and cisplatin for 5 days; results were compared with those obtained with bovine aortic endothelial cells. Cell proliferation was assessed with the sulforhodamine B colorimetric cytotoxicity assay. Apoptosis was quantitatively determined by flow-cytometric analysis for DNA damage and the apoptotic death assay for DNA fragmentation, and qualitatively by electron microscopy. Reverse transcriptase/polymerase chain reaction analysis and an enzyme immunoassay were used to determine the mRNA and protein level, respectively, of the anti-apoptotic bcl-2 gene product. We found that bFGF enhanced cisplatin-induced cytotoxicity in MCF-7 breast cancer sublines. bFGF enhanced proliferation of normal endothelial cells and did not increase cisplatin-induced cytotoxicity. This effect was accompanied by down-regulation of the anti-apoptotic protooncogene bcl-2 and the enhancement of cisplatin-induced apoptosis. We suggest that the improved understanding of the role of bFGF in the differential modulation of the response of breast cancer and normal endothelial cells to chemotherapy may enable active intervention to alter the therapeutic ratio favorably in breast cancer patients.
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  • 14
    ISSN: 1432-1335
    Keywords: Keywords Chemosensitivity ; Human gastric carcinoma ; Micrometastasis ; Apoptosis ; Circulating tumor cells ; Fluoropyrimidine
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Antimetastatic effects of 5-FU and its derivative, 1-hexylcarbamoyl-5-fluorouracil (HCFU) on human gastric cancer micrometastasis and their mode of action were evaluated, using a spontaneous lung metastasis model (HY-1) in nude mice. Metastases were first detected in the lung from 4 weeks after subcutaneous transplantation, growing intravascularly and forming micrometastases at 100% incidence by 6 weeks after implantation. Lung metastasis in mice bearing subcutaneous tumors was significantly inhibited by HCFU at doses of 100–150 mg kg−1 day−1 without severe toxic side-effects, when orally administered three times per week either from week 4 or week 6 to 9 weeks after implantation. Spontaneous lung metastasis was also inhibited by the administration of 5-FU, but to lesser extent than with HCFU at equimolar low doses. Apoptosis within primary tumors and lung metastatic foci, as detected by the terminal-deoxynucleotidyltransferase-mediated dUTP nick-end labeling method, was found to be significantly enhanced by HCFU as well as 5-FU administration at doses of more than 100 mg kg−1 day−1 and 50 mg kg−1 day−1 respectively. However, proliferating activity of the metastatic foci, as evaluated by MIB-1 immunostaining, was not significantly suppressed by HCFU or 5-FU treatment. Furthermore, polymerase chain reaction analysis using human specific primers for the β-globin gene, which proved to be capable of detecting 10 tumor cells/ml mouse blood, revealed that circulating tumor cells in the peripheral blood of mice bearing primary tumors were reduced by HCFU or 5-FU administration. These results indicate that circulating tumor cells in blood and micrometastases in the lung are sensitive to these chemotherapeutic agents, and suggest that the anti-metastatic effect of these agents is mediated, at least in part, by enhanced apoptosis rather than by inhibition of cell proliferation.
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  • 15
    ISSN: 1432-1335
    Keywords: Key wordsIGF ; Apoptosis ; Transformation ; Chemosensitivity ; Signaling
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Insulin-like growth factor I (IGF-I) exerts pleiotropic effects on mammalian cells via stimulation of its receptor (IGF-IR), a receptor tyrosine kinase. In vivo, IGF-I acts both as a local tissue growth factor and as a circulating hormone. In oncological research, IGF-I has received increased attention as the activated IGF-I/IGF-IR system displays mitogeneic, transforming, and anti-apoptotic properties in various cell types by stimulating distinct intracellular signaling pathways. Recent data suggest that the anti-apoptotic effect of IGF-I may mediate decreased sensitivity to chemotherapeutic drugs in vitro and in vivo. Thus, targeting the IGF-I/IGF-IR system could serve as an approach to overcome clinical drug resistance in certain tumors.
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  • 16
    ISSN: 1432-1335
    Keywords: Key words Immunohistochemistry ; DNA repair ; Radiation-inducible response ; Apoptosis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Immunohistochemical methods were used to determine abundance and subnuclear distribution of DNA topoisomerase I and the Bax protein in normal and excision-repair-deficient xeroderma pigmentosum (XP) fibroblasts after irradiation of cells with γ rays or UV light, or exposure to the topoisomerase I inhibitor topotecan. DNA topoisomerase I and Bax were monitored using antisera raised against the human proteins. In addition, topoisomerases IIα and IIβ were made visible with specific antibodies. In untreated cells, DNA topoisomerase I was found to occur in the cytoplasm and in nucleoli. Irradiation with γ rays (2–12 Gy) or UV light (0.3–1.2 mW/cm2) changed the staining pattern in nuclei such that a multitude of small topoisomerase-I-rich centers occurred, which were evenly distributed over the karyoplasm. Simultaneously nucleoli disintegrated. Treatment of fibroblasts with topotecan (6–100 μM concentrations) resulted in similar alterations although the changes were much more pronounced. Combinations of topotecan and γ irradiation caused additive effects. We conclude that the increase in the number of topoisomerase-I-positive spots and the high fluorescence intensity of the latter may reflect three biological processes: (i) enhanced transcriptional activity (e.g. of DNA damage response genes), (ii) tagging of damaged DNA sites for repair, or (iii) initiation of apoptosis. In separate assays using normal and XP cells, a dose-dependent increase in protein reacting with Bax antibody was observed in nuclei, following treatment with γ rays or topotecan. In addition, topotecan induced a netlike arrangement of this Bax protein in nuclei. The meshes of the net structure resembled vesicles. DNA staining with 4′,6-diamidino-2-phenylindole dihydrochloride revealed that the vesicle-type structures contained DNA. Upon further incubation with topotecan, cells showing the netlike Bax arrangement eventually died. We conclude that topotecan-induced changes made visible by nuclear Bax protein are associated with apoptosis. XP cells, when treated with topotecan, responded more readily than normal cells with both an increase in nuclear Bax protein and rearrangement of Bax, indicating that UV repair functions may be required to process DNA damage inflicted by topotecan. Monitoring of DNA topoisomerases IIα and IIβ in γ-irradiated cells with antibodies revealed a dramatic increase in the IIα form and a redistribution of the IIβ form representing fragmentation of nucleoli.
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  • 17
    Electronic Resource
    Electronic Resource
    Springer
    Journal of cancer research and clinical oncology 125 (1999), S. 357-360 
    ISSN: 1432-1335
    Keywords: Key words Colorectal neoplasms ; Apoptosis ; Chemosensitivity ; p53 gene
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Purpose : The p53 gene is considered one of the most important in the control of apoptosis, and its mutations have a close relationship with chemosensitivity. The aim of this work was to investigate the role of p53 in the apoptosis of colorectal cancer cells in vitro, induced by 5-fluorouracil (5-FU) and hydroxy-camptothecin (HCPT). Methods : A total of 39 colorectal cancer samples from patients were treated in vitro with 5-FU (10 μg/ml), 5-FU (10 μg/ml) + leucovorin (5 μg/ml), HCPT (0.1 μg/ml) and HCPT (0.1 μg/ml) + Salvia mitorrhiza (6 μl), using an in situ terminal deoxynucleotidyltransferase assay to detect chemosensitivity. p53 gene mutations from tumor DNA were detected, after amplification by the polymerase chain reaction of exons 5–8, by non-radioactive single-strand conformation polymorphism. Results : p53 gene mutations were observed in 43.6% (17/39) of colorectal carcinomas, when the terminal deoxynucleotidyltransferase assay was used to detect the tumor apoptotic rate. Cells with mutated p53 had lower chemosensitivity than those without (p 〈 0.01). Conclusion : Routine assessment of p53 status may be helpful in selecting patients with the wild-type p53 gene, who have a predictably better response to chemotherapy.
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  • 18
    ISSN: 1432-1335
    Keywords: Key words EGF receptor signalling ; Tyrphostin ; Apoptosis ; Colon cancer
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Growth effects of tyrphostins A25 and AG1478 on colorectal tumor cells were studied to explore therapeutic potential. Cell number, DNA synthesis and apoptotic index were measured as growth parameters and cell-death-associated proteins Bcl-2 and Bak and protein phosphorylation were analyzed. Both tyrphostins inhibited DNA synthesis and induced apoptosis in tumor cell cultures with different patterns of activity. A25 displayed strong selectivity for the cell lines expressing high levels of epidermal growth factor (EGF), HT29/HI1 and SW480. Inhibition of DNA synthesis was efficient in all cells except T84, and the apoptotic index increased two- to fivefold. By contrast, AG1478 was highly effective in all cell lines. In addition, it caused cell loss in VACO235 adenoma cells at concentrations lower than those necessary to inhibit BrdU incorporation, reflecting preferential retention of cells actively synthesizing DNA. Induction of apoptosis was more efficient with AG1478 than with A25 (tenfold in VACO235). Insulin-like growth factor (IGF1) did not rescue cells exposed to A25 or to high concentrations of AG1478, but was effective with suboptimal amounts of AG1478. Both compounds inhibited phosphorylation of the EGF receptor as well as additional proteins. AG1478 induced expression of Bak and down-regulated Bcl-2. In summary, tyrphostins may provide alternatives for colorectal tumor treatment. Their broader range of activities and the lower susceptibility to interactions with IGF1 can be an advantage over receptor antibodies.
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  • 19
    ISSN: 1432-1335
    Keywords: Key words Experimental pancreatic cancer ; Hormonal therapy ; Bombesin antagonist ; Somatostatin analog ; LH-RH antagonist ; EGF receptor ; Apoptosis ; AgNOR
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Reduction in receptors for epidermal growth factor (EGF) in cancers appears to be one of the principal mechanisms through which peptide hormone analogs can inhibit tumor growth. In this study, hamsters with nitrosamine-induced pancreatic cancers were treated for 8 weeks with bombesin/gastrin-releasing peptide (GRP) antagonist RC-3095, somatostatin analog RC-160 or the luteinizing hormone-releasing hormone antagonist Cetrorelix, using sustained delivery systems releasing 20, 35 and 20 μg analog/ day respectively. To establish the pattern of changes in the number and affinity of EGF receptors on tumors, groups of animals were sacrificed at regular intervals during therapy. Chronic treatment with RC-3095 or Cetrorelix resulted in an early (day 10) and sustained reduction (71% or 69% respectively) in EGF receptors on pancreatic tumors. In contrast, RC-160 decreased receptor concentration by 60% only after 20 days. Among the histological characteristics of proliferation, the decrease in argyrophilic nucleolar organizer regions, but not apoptotic and mitotic indices, showed a correlation with the fall in EGF receptors. The concentration of the receptors returned to the control level 4 days after cessation of chronic treatment with RC-3095. The effect of single injections of RC-3095, RC-160 and Cetrorelix on EGF receptors was also investigated. RC-160 decreased the number of EGF receptors on pancreatic cancers by 31% 3 h after administration, but the receptors had returned to normal level at 6 h. RC-3095 and Cetrorelix caused a 67% and 59% decline, respectively, in EGF receptors only 6 h after injection and the concentration of receptors remained low for 24 h. Thus, the pattern of down-regulation of EGF receptors in pancreatic cancers appears to depend on the peptide used for therapy. Since the antitumor effect may be the result of the fall in EGF receptors in cancers, information on the time course of changes in these receptors during treatment with these analogs may lead to an improvement in therapeutic regimens.
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  • 20
    ISSN: 1433-0474
    Keywords: Schlüsselwörter Ataxia teleangiectatica ; Immunfunktionsstörung ; Lymphozytensubpopulationen ; Apoptose ; CD45RO ; CD45RA ; Key words Ataxia teleangiectasia ; Immunodeficiency ; Lymphocyte subset ; Apoptosis ; CD45RO ; CD45RA
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Summary Background: Can a characterisation of the lymphocyte subset in patients with ataxia teleangiectasia offer an explanation for the cellular defect of their immunfunction? Methods: In ten patients with ataxia teleangiectasia and a corresponding control group of individuals of similar age and sex, immunophenotyping was carried out by means of flow cytometric analysis and the use of monoclonal antibodies. Results: Patients with ataxia teleangiectasia showed a reduction of the number of T-cells with a decrease in the T-helper cell subset (CD3: 990/µl, p〈0.0005 and CD4: 568/µl, p〈0.0005). The number of B-cells was low (CD19: 39/µl, p〈0.005). Moreover, there was an increase in highly activated T-lymphocytes which can be seen from a higher percentage of the HLA-DR- and CD45RO-expression in patients with ataxia teleangiectasia compared to the individuals of the control group (HLA-DR: 57%, p〈0.0005 and CD45RO: 82%, p〈0.001). At the same time, the expression of CD95 (Fas/AP01) was clearly increased (CD95: 74%, p〈0.001). Interpretation: The lymphocyte subset of the patients suffering from ataxia teleangiectasia shows a significant decrease of the B- and T-cell subsets. The reduced number of T-helper cells – caused by a CD45RA-cell loss – leads to a change in the relation „RA/RO”. It is possible that there is a link between the imbalance of „RA/RO”, the increase of highly activated T-lymphocytes and the higher expression of CD95 (Fas/APO1).
    Notes: Zusammenfassung Fragestellung: Können durch eine Charakterisierung der Lymphozytensubpopulationen bei Patienten mit Ataxia teleangiectatica Rückschlüsse auf den zellulären Defekt der Immunfunktionsstörung gezogen werden? Methodik: Mit Hilfe der Durchflußzytometrie und des Einsatzes monoklonaler Antikörper führten wir eine Immunophänotypisierung bei jeweils 10 Patienten mit Ataxia teleangiectatica und eines bezüglich des Alters und des Geschlechts gleichverteilten Kontrollkollektivs durch. Ergebnisse: Die Patienten mit Ataxia teleangiectatica zeigten verminderte T-Zell-Zahlen mit Abnahme der T-Helferzell-Subpopulationen (CD3: 990/µl, p〈0,0005 und CD4: 568/µl, p〈0,0005). Auch die B-Zell-Zahl war erniedrigt (CD19: 39/µl, p〈0,005). Die T-Lymphozyten befanden sich darüber hinaus vermehrt im aktivierten Zustand, erkennbar an einer prozentual erhöhten HLA-DR- und CD45RO-Expression (HLA-DR: 57%, p〈0,0005 und CD45RO: 82%, p〈0,001) sowie an einer Verschiebung der Relation „RA/RO” zugunsten der „RO”-Expression. Gleichzeitig war die Expression von CD95 (Fas/APO1) deutlich gesteigert (CD95: 74%, p〈0,001). Schlußfolgerung: Die Veränderungen der Lymphozytensubpopulationen zeigen bei den Patienten mit Ataxia teleangiectatica eine verminderte B- und T-Zell-Zahl. Die CD4-Lymphopenie – verursacht durch einen CD45RA-Zellverlust – bedingt eine Verschiebung der Relation „RA/RO”. Möglicherweise besteht ein Zusammenhang zwischen der Störung der Homöostase „RA/RO” und dem erhöhten Aktivierungsgrad der Zellen sowie der vermehrten CD95(Fas/APO1)-Expression.
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  • 21
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    Clinical and experimental nephrology 3 (1999), S. 254-260 
    ISSN: 1437-7799
    Keywords: Key words Low density lipoprotein ; Apoptosis ; Malondialdehyde ; TGFβ1 ; Unilateral ureteral obstruction
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Background. To test the hypothesis that oxidized low density lipoprotein (oLDL) is involved in the renal injury of obstructive nephropathy, male Sprague-Dawley rats weighing 125–150 g were used. Methods. Three days after arrival, the rats were randomly assigned to undergo: (1) sham operation, (2) left unilateral ureteral obstruction (UUO), or (3) reversal of the unilateral ureteral obstruction (R-UUO). Seven days after the reversal operation or 10 days after the sham or UUO procedure, all animals were killed by exsanguination under anesthesia, with blood taken from the abdominal aorta. LDL was prepared by gradient ultracentrifugation and used immedi-ately after isolation. Rat mesangial cells were utilized with an LDL concentration of 100 μg/ml/protein in the media. After 72 h, cell survival was determined by the 3-(4,5-dimethylthiazol-2-yl)-2,5 diphenyltetrazolium bromide (MTT) method. Cell survival was determined by comparing the optical density between the control wells and the experimental wells. In order to investigate the mechanisms of injury and repair of obstructive nephropathy, data for kidney apoptosis, malondialdehyde (MDA), and transforming growth factor β1 (TGFβ1) mRNA were obtained in the sham-operated, UUO, and R-UUO groups. Results. Our results showed that LDL malondialdehyde during UUO was increased 87% over baseline values (P 〈 0.005). With R-UUO, the oxidized LDL dropped 23% from the peak values during UUO (P 〈 0.005), but was still different from that of the baseline values (P 〈 0.025). Rat mesangial cell survival, after 72 h exposure to oLDL, inversely correlated to oLDL cytotoxicity and showed a 14% drop during UUO compared with sham-operated animals (P 〈 0.01). Cell survival increased 11% after R-UUO (P 〈 0.02) and was not different from control values (P = NS). The apoptotic counts by the TUNEL (terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick end-labelling) technique showed significant increases during UUO and a noticeable reduction after R-UUO. Conclusion. Our data support the proposition that UUO stimulates oxidation of LDL. The cytotoxicity of oLDL plays a significant role in the injury of UUO. A decrease in cytotoxicity was associated with the repair in R-UUO. Our observations that apoptosis follows this same pattern, point to the importance of apoptosis in the injury and repair of obstructive nephropathy. Future studies to interrupt these processes of injury may lead to novel treatment modalities in reversing the injury and hastening the repair of obstructive nephropathy.
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  • 22
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    Pediatric surgery international 15 (1999), S. 243-247 
    ISSN: 1437-9813
    Keywords: Key words Wilms' tumo ; Apoptosis ; Bcl-2
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Wilms' tumor (WT) usually has a good outcome, although a poor prognosis is often related to more advanced stages and anaplastic features. Apoptosis occurs with variable frequency in malignant tumors, and may have a role in reducing their growth rate. The bcl-2 proto-oncogene inhibits apoptosis, and the consequent increase in the number of cells may play a role in the development of tumors. The aim of this study was to analyze the role of apoptosis and bcl-2 expression in WT. Twenty-six resected WT specimens were studied; 12 patients had stage I tumor, 4 stage II, 5 stage III, 3 stage IV, and 2 stage V. Twenty-three tumors were classified as favorable histology (FH) and 3 as unfavorable (UH). The mean follow-up was 34 months; 22 patients were alive and 4 were dead (2 with FH: 1 stage III and 1 stage IV, and 2 with UH stages 4). Apoptosis was detected by the in-situ end-labelling technique; bcl-2 expression was detected by immunohistochemistry. An apoptotic index (AI) was calculated as the ratio of apoptotic to normal cells in each specimen. The AI was lower in higher tumor stages, with a significant difference between stages I and IV (P 〈 0.05). In cases with UH, Al was lower than in tumors with FH (P 〈 0.01). The AI was also lower in patients who died than in those who survived (P 〈 0.01). In all specimens no correlation between AI and bcl-2 expression was observed. Progression to advanced stages of WT and a poor prognosis f anaplastic tumors may be linked with disruption of the mechanisms that control apoptosis. Bcl-2 does not play a role as a regulator of apoptosis in WT, other oncogenes and tumor-suppression genes may be more involved in inhibiting apoptosis in WT.
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  • 23
    ISSN: 1437-773X
    Keywords: Key words Epithelial rest of Malassez ; Cell ; cell interaction ; Extracellular matrix ; In vitro ; Apoptosis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The present study investigated how cell plating density and extracellular matrix protein influence cell survival of epithelial rests of Malassez (ERM) in vitro. ERM cells were plated on culture dishes coated with laminin (LM), type IV collagen (type IV), or fibronectin (FN), or on noncoated dishes, (Non) at a cell density of 2 × 104–1 × 105/ml in a nonserum culture medium. XTT assays were performed to calculate the number of cells attached on the substrata after 6, 24, 48, and 72 h. Mean cell numbers were calculated, and significant differences were determined using ANOVA. When epithelial cells were cultured on various matrices at a cell density of less than 2 × 104/ml, the cells did not grow and then fell into apoptotic cell death, which was confirmed by transmission electron microscopy. The cell number was significantly increased in cells plated on FN compared to those on Non at a cell density of 4 × 104/ml–8 × 104/ml. These results suggest that both extracellular matrix proteins and cell–cell interactions may contribute to prevent apoptosis of ERM in vitro. Cell–cell interactions may be a more important factor than exogenous extracellular matrix proteins for the survival of ERM cells in vitro.
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  • 24
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    Journal of infection and chemotherapy 5 (1999), S. 139-143 
    ISSN: 1437-7780
    Keywords: Key words Fas ; ADR ; Bladder cancer ; Synergy ; Apoptosis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Fas and Fas ligand play an important role in cytotoxic T lymphocyte-mediated cytotoxicity. Like Fas ligand, anti-Fas monoclonal antibody (mAb) induces apoptosis of cells expressing Fas and mimics tumor necrosis factor-α (TNF-α) in its cytotoxic activity, but not in regard to other TNF-α-mediated activities. Since combination treatment with TNF-α and some anticancer chemotherapeutic agents results in synergistic cytotoxicity against various cancer cells, anti-Fas mAb may also synergize with anticancer agents in exerting cytotoxicity. The present study examined this hypothesis using bladder cancer cells. Cytotoxicity was examined by a 1-day microculture tetrazolium dye assay. Treatment of T24 cells with anti-Fas mAb in combination with mitomycin C, methotrexate, or 5-fluorouracil did not overcome their resistance to these agents. However, combination treatment with anti-Fas mAb and adriamycin (ADR) resulted in a synergistic cytotoxic effect on T24 cells, three other bladder cancer lines, and fresh bladder cancer cells derived from four patients. Treatment with ADR enhanced the expression of Fas on T24 cells. The expression of P-glycoprotein was not affected by the antibody-mediated sensitization. This study showed that combination treatment of bladder cancer cells with anti-Fas mAb and ADR can overcome their resistance and that the upregulation of Fas expression by ADR may play a role in the enhanced cytotoxicity.
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  • 25
    ISSN: 1437-773X
    Keywords: Key words Hepatocellular carcinoma ; Apoptosis ; Fas protein ; Bcl-2 protein
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Because the induction of apoptosis in cancer cells is very important in clinical management, it is useful to examine the association with the Fas–Fas ligand pathway and Bcl-2 protein family in apoptosis. We morphologically examined the expression of Fas and Bcl-2 proteins and induction of apoptosis by anti-Fas in four human hepatocellular carcinoma cell lines, PLC/PRF/5, Huh-6, and Huh-7, as well as OCUH-16, which was originally established in our university. Fas protein was expressed in 96% of OCUH-16 cells in cytoplasm, 24% of PLC/PRF/5 cells, 20% of Huh-6 cells, and no Huh-7 cells. Bcl-2 protein was expressed in 43%–72% of cells in cytoplasm and nuclei of the four lines examined. Administration of anti-Fas induced apoptosis in about 40% of OCUH-16 cells, but did not induce apoptosis in the other three cell lines. In conclusion, an original cell line, OCUH-16 cells, expressed Fas and Bcl-2 proteins and underwent apoptosis following treatment with anti-Fas, but the other three cell lines examined did not undergo apoptosis. OCUH-16 cells are thus very useful for the study of apoptosis and molecules related to apoptosis at the levels of cell-surface receptors and intracytoplasmic regulation of apoptosis.
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  • 26
    ISSN: 1437-7772
    Keywords: Key words Ovarian cancer ; Apoptosis ; IL-6 ; CDDP ; Taxol
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Background. Apoptosis is a cascade of events that is regulated by many factors. We studied the effects of interleukin-6 (IL-6) on chemotherapy-induced apoptosis in three human ovarian cancer cell lines (JV, GG, and NF). Methods. Cells were treated with the anticancer drugs cis-diamminedichloroplatinum (II) (CDDP) and paclitaxel (Taxol; Bristol-Myers Squibb Pharmacessticals, Noble Park, Australia) over a period of 72 h. The treatments were repeated in combination with human recombinant IL-6 or anti-IL-6 monoclonal antibody (anti-IL-6 mAb). The induction of cell death was examined by morphology and by internucleosomal DNA fragmentation. Results. Reduced cytotoxicity and fewer apoptotic cells were observed after treatment with CDDP or Taxol combined with IL-6 compared with treatment with CDDP or Taxol alone. However, treatment with CDDP or Taxol combined with anti-IL-6 mAb enhanced the cytotoxic effects of the drugs and increased the number of apoptotic cells. These findings indicated that apoptosis caused by CDDP or Taxol was influenced negatively by high doses of IL-6. Conclusion. The use of CDDP or Taxol combined with anti-IL-6 mAb may have therapeutic value for patients with ovarian cancer.
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  • 27
    ISSN: 1432-2307
    Keywords: Key words Anencephaly ; Thymic hyperplasia ; CD99 ; Apoptosis ; Aggregation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  In a significant proportion of cases, anencephaly is associated with thymic enlargement, suggesting a possibility that anencephalic fetuses have a functional disturbance in thymocyte differentiation and development. In this report, we demonstrated that CD99 expression was consistently reduced in cortical thymocytes of all anencephalic fetuses. In addition, the CD99-dependent aggregation of immature cortical thymocytes was almost completely impaired and apoptosis of thymocytes was markedly reduced in several cases. These results are in agreement with previous findings that CD99 regulates the aggregation and apoptosis of various types of cells. These data strongly suggest that functional disturbance of thymocytes and thymic hyperplasia are related to the reduced expression of CD99 molecule in anencephalic fetuses.
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  • 28
    ISSN: 1436-2813
    Keywords: Key Words: nitric oxide ; DNA damage ; apoptosis ; tumor necrosis factor-α ; mitochondrial respiration
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: S -nitroso-N-acetylpenicillamine protected cul-tured L929 cells from apoptosis induced by tumor necrosis factor-α (TNF-α) plus actinomycin D, as determined by the detection of DNA fragmentation and morphological changes. NO also prevented an enhancement of the production of reactive oxygen intermediates by TNF-α plus actinomycin D, as assessed by the oxidation of dihydrorhodamine 123 and hydroethidine. Because the inhibition of mitochondrial respiration by rotenone or antimycin A suppressed the increased oxidation of both dihydrorhodamine 123 and hydroethidine, it was suggested that TNF-α accelerated the leakage of reactive oxygen intermediates from the mitochondrial electron transport system. Polarography showed that NO reversibly inhibited mitochondrial respiration at either complexes I–III, II–III, or IV, thus suggesting the inhibition of cytochrome oxidase. Taken together, these findings indicate that the decreased mitochondrial formation of reactive oxygen intermediates in the presence of NO might have a protective effect against TNF-α plus actinomycin D-induced apoptosis.
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  • 29
    ISSN: 1436-2813
    Keywords: angiogenesis ; p53 ; apoptosis ; lung adenocarcinoma ; hematogenous metastasis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The purpose of this study was to clarify which factors are important as predictors not only of patient survival but also of hematogenic metastasis in 15 patients with stage I lung adenocarcinoma who underwent curative operation. The relationship between tumor angiogenesis, apoptosis, and p53 oncogene was also studied. A total of 15 patients were divided into two groups: surviving group (n=7) and nonsurviving (metastasis) group (n=8). We studied the medical charts, operative records, pathologic reports, and tumor specimens taken at surgical resection. We measured the apoptotic index using the ApopTag kit and the intratumoral microvessel count using an anti-CD34 monoclonal antibody. In addition, immunohistochemical staining for the expression of p53 was conducted simultaneously. The clinicopathological characteristics, including age, sex, tumor size (pT), and histological differentiation, were not significantly different between the surviving and the nonsurviving group. The microvessel count was significantly higher in nonsurviving group than in the surviving group. The apoptotic index and the expression of p53 was not significantly different between the two groups. An inverse correlation between the apoptotic index and microvessel count, and a positive correlation between the expression of p53 and microvessel count, were observed. Angiogenesis may be an important prognostic factor in patients with stage I lung adenocarcinoma.
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  • 30
    ISSN: 1436-2813
    Keywords: Key Words: angiogenesis ; p53 ; apoptosis ; lung adenocarcinoma ; hematogenous metastasis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: n = 7) and nonsurviving (metastasis) group (n = 8). We studied the medical charts, operative records, pathologic reports, and tumor specimens taken at surgical resection. We measured the apoptotic index using the ApopTag kit and the intratumoral microvessel count using an anti-CD34 monoclonal antibody. In addition, immunohistochemical staining for the expression of p53 was conducted simultaneously. The clinicopathological characteristics, including age, sex, tumor size (pT), and histological differentiation, were not significantly different between the surviving and the nonsurviving group. The microvessel count was significantly higher in nonsurviving group than in the surviving group. The apoptotic index and the expression of p53 was not significantly different between the two groups. An inverse correlation between the apoptotic index and microvessel count, and a positive correlation between the expression of p53 and microvessel count, were observed. Angiogenesis may be an important prognostic factor in patients with stage I lung adenocarcinoma.
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  • 31
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    Mund-, Kiefer- und Gesichtschirurgie 3 (1999), S. 210-212 
    ISSN: 1434-3940
    Keywords: Schlüsselwörter Plattenepithelkarzinom ; Tumorneoangiogenese ; Apoptose ; Key words Squamous cell carcinoma ; Tumor neoangiogenesis ; Apoptosis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Paclitaxel and docetaxel are potent drugs that are effective in the treatment of malignant tumors. The cytotoxic action of these drugs is not fully understood, but it appears to be mediated mainly through mitotic arrest and subsequent apoptosis. Because no information is available on the antiangiogenesis action of docetaxel, the investigations were performed to determine whether inhibition of neoangiogenesis plays a role in docetaxel’s antitumor efficacy. Four different mouse tumors, two squamous cell carcinomas (SCC-IV; SCC-VII) and two adenocarcinomas (MCA-4; MCA-29) were assayed for angiogenic activity using the in vivo i.c. angiogenesis assay. Tumor cells (5 × 105) were injected i.c. into the skin flap over the abdominal wall, and the number of new blood vessels at the tumor cell injection site was determined 2, 4, 6, 8, 10 and 12 days later. The mice were treated with docetaxel (Taxotere – 31.3 mg/kg i.v.) 1 or 4 days after tumor cell injection. The number of new blood vessels increased with time. Docetaxel reduced the number of newly formed blood vessels in MCAs, but not in SCCs. The reduction was associated with slower tumor growth. In a separate set of experiments we observed that docetaxel’s inhibitory effect on the two MCAs was histologically associated with massive tumor cell destruction by means of both apoptosis and necrosis. This was not observed for the two SCCs. Since no reduction in blood vessels occurred in tumors unresponsive to docetaxel, the inhibition of neoangiogenesis in docetaxel-responsive tumors was likely the result of a decrease in angiogenic stimuli due to docetaxel’s destruction of tumor cells.
    Notes: Die zytotoxische Aktivität der Taxane Paclitaxel und Docetaxel ist zum jetzigen Zeitpunkt noch nicht vollständig erklärt. Diese, zur Behandlung maligner Tumoren eingesetzten antineoplastischen Chemotherapeutika, scheinen jedoch weitgehend über die Blockierung der Mitose und die nachfolgende Induktion der Apoptose zu wirken. Über eine evtl. Hemmung der Neoangiogenese, wie sie kürzlich für Paclitaxel beschrieben wurde, liegen für Docetaxel noch keine Studienergebnisse vor. Es wurde deshalb untersucht, ob die therapeutische Aktivität von Docetaxel zur Hemmung der Neoangiogenese im Tumor beitragen kann. 4 murine Tumoren, 2 Plattenepithelkarzinome (SCC-VII; SCC-IV) und 2 Adenokarzinome (MCA-4; MCA-29), wurden in einem quantitativen intrakutanen In-vivo-Angiogenese-Assay experimentell untersucht. 5 · 10 5 Tumorzellen wurden in einen Abdominallappen der Maus injiziert. Die Anzahl neuformierter Blutgefäße und das Tumorwachstum wurden im 2tägigen Intervall über einen Zeitraum von zwischen 10 und 14 Tagen bestimmt. 2 Behandlungsgruppen wurde am 1. oder 4. Tag nach der Tumorzellinokulation Docetaxel (Taxotere – 31,3 mg/kg) i.v. injiziert. Die Plattenepithelkarzinome waren gegenüber der Therapie mit Docetaxel nicht sensibel, während die Adenokarzinome mit einer Abnahme der Gefäßzahl und einer Reduktion des Tumorvolumens reagierten. Histologisch zeigten die Adenokarzinome außerdem eine massive Tumorzelldestruktion durch Apoptose und Nekrose. Da die gegenüber Docetaxel nichtsensiblen Tumoren (Plattenepithelkarzinome) nicht mit einer Abnahme der Gefäßzahl reagierten, ist der beschriebene Effekt in den Adenokarzinomen am ehesten als indirekte Wirkung von Docetaxel zu werten. Die Tumorzelldestruktion führte in den betroffenen Tumoren zu einer verminderten Freisetzung endothelialer Mitogene wie VEGF und bFGF und zur Hemmung der Tumorneoangiogenese.
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  • 32
    ISSN: 1434-0879
    Keywords: Keywords Ischemia-reperfusion ; Heat shock ; HSP70 ; Kidney ; Apoptosis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Ischemia-reperfusion injury in the kidney is known to cause induction of the inducible form of the 70 kDa heat shock protein HSP70i (or HSP72). However, knowledge of the expressional regulation of the two coding genes for HSP70i –HSP70-1 gene and HSP70-2 gene – is very limited. We investigated the time course of HSP70-1 and -2 mRNA expression and its relation to cellular ATP levels in the renal cortex after different periods of unilateral warm renal ischemia (10–60 min) and reperfusion (up to 60 min) in 10-week-old male Wistar rats. Immediately after ischemia there was a significant induction of both HSP70i genes. While HSP70-1 expression constantly increased (up to 4-fold) during reperfusion, even to a higher extent with prolongation of ischemia, HSP70-2 mRNA – which was generally expressed at a far lower level than HSP70-1 mRNA – was strongly induced (3-fold) during reperfusion only after brief periods (10 min) of ischemia. Cellular ATP levels rapidly dropped to 5% with ischemia and the pattern of recovery during reperfusion significantly depended on the duration of the ischemic period, thus showing a good relation with the heat shock (protein) gene expression. We conclude that HSP70-2 is the more sensitive gene with a lower activation threshold by mild injury, while the HSP70-1 gene mediates the major response of heat shock protein induction after severe injury.
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  • 33
    ISSN: 1434-0879
    Keywords: Keywords Testicular neoplasms ; Embryonal cell ; carcinoma ; Apoptosis ; Lymphocytes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Disorders in the regulation of apoptotic cell death may contribute to cancer. Furthermore, lymphocytes are supposed to play a role in counteracting tumorigenesis by inducing apoptosis in different human tumors. In this study, for the first time, tumor cell and lymphocyte apoptosis were investigated systematically in human embryonal cell carcinoma. DNA fragmentation and DNA condensation were measured simultaneously on double-fluorescence-labeled testis tumor sections using immunofluorescence microscopy. Different apoptotic indices (AIs), based either on biochemical (DNA fragmentation) or morphological criteria (DNA condensation) alone or on a combination of both, were determined in different histological regions in and around the tumor. Using morphological criteria alone, 40–75% of all apoptotic cells were not detected. Based on previous observations this finding might be related to subsets of apoptotic cells which induce the process of DNA condensation without activation of processes responsible for DNA fragmentation. Moreover, the AIs of tumor cells and lymphocytes were highest in the tumor region, compared with regions around the tumor and distant from it; these findings are discussed in the context of the Fas/FasL system.
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  • 34
    ISSN: 1432-0533
    Keywords: Key words c-Jun ; Jun B ; Jun D ; Apoptosis ; Colchicine
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The expression of members of the Jun family of transcription factors was examined by immunohistochemistry, Western blotting, in situ hybridization and Northern blotting in the developing and adult rat brain following colchicine administration. Apoptotic cells, as revealed by their typical morphology and positive staining with the method of in situ end-labeling of nuclear DNA fragmentation, were restricted to granule cells of the dentate gyrus and olfactory bulb, and a few cells in the upper layers of the entorhinal cortex in adult rats, whereas widespread apoptosis occurred in developing rats after colchicine administration. No modifications in the expression of Jun D and Jun B, except for a generalized and moderate Jun B expression in glial cells, were observed in colchicine-treated rats. Generalized and strong c-jun mRNA induction and c-Jun/AP-1 (Ab-1) protein expression was observed in the cerebral neocortex, entorhinal and piriform cortices, CA1 and CA3 areas of the hippocampus and granule cell layer of the dentate gyrus in adult treated rats, thus indicating a generalized c-Jun response to colchicine administration. In contrast, c-Jun/AP-1 (N) and c-Jun/AP-1 (Ab-2) immunoreactivity was restricted to apoptotic cells in colchicine-treated adult and developing brains. Western blots of hippocampal homogenates and total brain homogenates in adult and developing rats, respectively, demonstrated a band of 39 kDa for the c-Jun/AP-1 (Ab-1) antibody in control animals, the intensity of which increased in colchicine-treated rats. However, a band of 37 kDa, the intensity of which also increased following colchicine administration, was observed for the c-Jun/AP-1 (N) and c-Jun/AP-1 (Ab-2) antibodies. Selective c-Jun/AP-1 (N) and c-Jun/AP-1 (Ab-2) expression was also observed in apoptotic cells of the SH-SY5Y neuroblastoma line after the addition of colchicine to the culture medium. Taken together, the present in vivo and in vitro results indicate a generalized c-Jun response to colchicine in sensitive cells, whereas the antibodies c-Jun/AP-1 (N) and c-Jun/AP-1 (Ab-2) recognize vulnerable cells dying via apoptosis.
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  • 35
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    Acta neuropathologica 97 (1999), S. 192-195 
    ISSN: 1432-0533
    Keywords: Key words Neuronal vacuolation ; Rottweiler dog ; Bcl-2 ; Bax ; c-Jun ; Apoptosis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Neuronal vacuolation, involving the cerebellar roof nuclei, Purkinje cells, selected nuclei of the brain stem, thalamus, Clarke’s column, anterior and posterior horns of the spinal cord, visceral autonomic ganglia and myenteric plexus, as well as axonal degeneration of the white matter of the brain stem, cerebellar pedunculi, dorsolateral columns of the spinal cord and ventral roots of the spinal cord, were observed in two young Rottweiler dogs which were clinically afflicted with hind limb weakness progressing to paraparesia, ataxia, intention tremor, and difficulty in swallowing and barking. The absence of modifications in Bcl-2 and Bax immunoreactivity, a lack of strong c-Jun/AP-1 (N) immunoreactivity in vacuolated cells, and the absence of DNA breaks, as seen with the method of in situ end-labeling of nuclear DNA fragmentation, all suggest that there is no involvement of the apoptotic pathway in vacuolated cells in this new neurodegenerative disorder.
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  • 36
    ISSN: 1432-0533
    Keywords: Key words Glucocorticosteroids ; Apoptosis ; Guillain-Barré syndrome
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Lipocortin-1 exerts a potent immunosuppressive effect on pathogenic T cells. In multiple sclerosis and experimental autoimmune encephalomyelitis levels of lipocortins are raised, suggesting their involvement in the recovery from an immunological insult or in neural regeneration. To further understand the role of lipocortins in the peripheral nervous system we have characterized lipocortin-1 levels and cellular distribution of lipocortin-1 immunoreactivity in sciatic nerves of rats with experimental autoimmune neuritis (EAN), a model of human Guillain-Barré syndrome. EAN was induced actively by immunization with bovine peripheral myelin (active EAN) or by adoptive-transfer (AT-EAN) of P2-specific T cells. Cellular infiltrates in serial and semithin cryosections were characterized by immunohistochemistry. In parallel, lipocortin-1 levels in tissue extracts were quantified by a sandwich-ELISA. Only weak lipocortin-1 immunoreactivity was found in nerves of control animals injected with non-pathogenic T cells. The majority of macrophages and lymphocytes in EAN lesions exhibited lipocortin-1 immunoreactivity. Some very heavily stained cells showed a distribution and morphology similar to ED-2-positive macrophages which were abundant during early stages of EAN. Lipocortin-1 expression in T cells and macrophages was proven by immunocytochemical studies in semithin serial sections. In tissue extracts, lipocortin-1 levels increased from 0.24 ± 0.14 μg/mg protein in controls receiving non-pathogenic T cells to a maximum of 0.55 ± 0.1 μg/mg protein in AT-EAN at the peak of disease, and then slowly decreased during clinical recovery but still remained elevated. In dose-response studies in AT-EAN, highest values of lipocortin-1 (0.71 ± 0.23 μg/mg protein) were recorded after transfer of 2 × 107 T cells. Increased levels of lipocortin-1 were also measured in active EAN but occurred during the recovery phase (0.65 ± 0.27 μg/mg protein). By analogy with other immune-mediated disorders, increased lipocortin-1 expression in the inflamed sciatic nerve in EAN may exert immunoregulatory functions in-situ and contribute to the termination of the autoimmune response.
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  • 37
    ISSN: 1432-0533
    Keywords: Key words Immediate early gene ; Heat shock protein ; Cerebral ischemia ; Apoptosis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The neuroprotective role of the expression of heat shock protein (HSP) and immediate early gene remains unclear. Using immunoelectron microscopy, we examined the ultrastructural integrity of the neurons with expression of c-Fos, c-Jun and HSP70 in gerbils after transient cerebral ischemia and repefusion. Induction of c-Fos and c-Jun was observed in the CA3 region resistant to ischemia, while HSP70 was expressed not only in the CA3 but also in the vulnerable CA1 region. With immunoelectron microscopy, the expression of c-Fos/c-Jun and HSP70 was observed in the neurons which retained neuronal integrity except for mitochondrial swelling and polyribosomal disaggregation. In contrast, the CA1 neurons without immunoreaction for HSP70 showed cytoplasmic vacuoles and parallel stacking of rough endoplasmic reticulum, the features associated with the process of delayed neuronal death. These findings suggested that c-Fos and c-Jun were induced selectively in reversibly damaged neurons, whereas HSP70 was up-regulated even in neurons with irreversible damage, but was more preferentially and intensely expressed in neurons with reversible damage.
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  • 38
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    Acta neuropathologica 97 (1999), S. 5-12 
    ISSN: 1432-0533
    Keywords: Key words Creutzfeldt-Jakob disease ; Apoptosis ; Cell death ; Prion protein ; In situ end-labeling of nuclear DNA fragmentation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The method of in situ end-labeling of nuclear DNA fragmentation was used in the study of ten patients (two biopsies, eight autopsies) with sporadic Creutzfeldt-Jakob disease (CJD). All the patients had the typical morphological lesions including neuron loss, spongiform change and astrocytosis. Four of them also showed prion protein (PrP) deposits in the cerebral cortex, and two of them kuru-like plaques in the cerebellum. A few cells with DNA breaks were found in the two biopsy cases; one of them, suffering from a panencephalopathic form of the disease, showed positive nuclei not only in the cerebral cortex but also in the subcortical white matter. Variable numbers of positive nuclei were observed in the gray and white matter in the eight autopsy cases, in which, although the distribution of positive cells roughly correlated with the distribution of neuron loss, no clear relationship was found as regards the distribution and degree of cell labeling and the degree of neuron loss. Furthermore, large numbers of positive cells were concentrated in a particular area, whereas a few cells were seen in a neighboring equally affected area. Positive glial cells in the plexiform layer of the CA1 area of the hippocampus, and in the frontal white matter were frequently encountered. Staining of the cytoplasm in a minority of cells was interpreted as the result of nuclear DNA leakage. None of the stained cells had the typical morphology of apoptosis; most particularly, peripheral chromatin condensation and formation of apoptotic bodies were not seen in any case. PrP deposits did not result in an increase of nuclear DNA breaks either within the area or in adjacent regions. Although positive cells were also observed in autopsy cases of controls which were processed in the same way, positive labeling as a whole was higher in CJD than in age-matched controls. These results show that brain nuclear DNA is vulnerable in CJD, and suggest that increased DNA vulnerability has a role in cell death and neuron loss. Since nuclear shrinkage and positive nuclear staining with the method of in situ end-labeling of nuclear DNA fragmentation are not exclusive to apoptosis, further information is needed to categorize cell death in CJD as apoptosis. Necrosis or other forms of cell death, as well as increased DNA vulnerability to agonal changes of the individuals, and to postmortem delay in the fixation of the tissues, may account for additional positive staining in cases examined at autopsy.
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  • 39
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    Anatomy and embryology 200 (1999), S. 203-214 
    ISSN: 1432-0568
    Keywords: Key words Extracellular material ; Cell proliferation ; Apoptosis ; Anoikis ; Tenascin ; Laminin
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  Extracellular material molecules play a key role in the regulation of morphogenesis and differentiation of a large number of organs including the central nervous system. However, the role of the neural basement membrane in the growth of different parts of the neural tube has yet to been delineated. Here, the structural and compositional modifications of the basement membrane (BM) of rhombencephalic tectoria lamina anlage (RTLA) have been examined during the process of RTLA epithelial attenuation. Between stages 10 to 11– the presumptive RTLA epithelium showed a structure, thickness and cell-proliferating capacity similar to those observed in other zones of the rhombencephalic walls. Moreover, the rhombencephalic vesicles were surrounded by a continuous BM that was heterogeneous both ultrastructurally and with regard to ruthenium red, laminin and tenascin distribution. After stage 11, the RTLA epithelium underwent a rapid process of attenuation and change to a stratified flattened epithelium. During this remodelling process, apoptosis and inhibition of both PCNA expression and 3H-thymidine uptake occurred in the RTLA epithelium. The BM of the RTLA underwent a process of degration at the beginning of the remodelling, and apoptosis and cell proliferation inhibition of RTLA epithelium were also observed. The loss of the biochemical signals encoded within the BM could lead to cell shape changes, cell proliferation inhibition and to the anoikis type of cell death. Our findings support the idea that the BM surrounding the neural tube plays a key role in controlling both the structure and growth of the CNS during the early developmental stages.
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  • 40
    ISSN: 1432-0568
    Keywords: Key words Somite explant culture ; Sonic hedgehog protein ; Myogenic induction ; Primary fiber type diversity ; Apoptosis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  Primary skeletal muscle fibers first form in the segmented portions of paraxial mesoderm called somites. Although the neural tube and notochord are recognized as crucial in patterning myogenic cell lineages during avian and mammalian somitic myogenesis, the source, identities, and actions of the signals governing this process remain controversial. It has been shown that signals emanating from the ventral neural tube and/or notochord alone or Shh alone serve to activate MyoD expression in somites. However, beyond a role in initiating MyoD expression, little is known about the effects of Shh on primary muscle fiber formation in somites of higher vertebrates. The studies reported here investigate how the ventral neural tube promotes myogenesis and compare the effects of the ventral neural tube with those of purified Shh protein on fiber formation in somites. We show that purified Shh protein mimics actions of the ventral neural tube on somites including initiation of muscle fiber formation, enhancement of numbers of primary muscle fibers, and particularly, the formation of primary fibers that express slow myosin. There is a marked increase in slow myosin expression in fibers in response to Shh as somites mature. The effects of ventral neural tube on fiber formation can be blocked by disrupting the Shh signaling pathway by increasing the activity of somitic cyclic AMP-dependent protein kinase A. Furthermore, it was demonstrated that apoptosis is a dominant fate of somite cells, but not somitic muscle fibers, when cultured in the absence of the neural tube, and that application of Shh protein to somites reduced apoptosis. The block to apoptosis by Shh is a manifestation of the maturity of the somite with a progressive increase in the block as somites are displaced rostrally from somite III forward. We conclude that purified Shh protein in mimicking the effects of the ventral neural tube on segmented mesoderm can exert pleiotropic effects during primary myogenesis, including: control of the proliferative expansion of myogenic progenitor cells, antagonism of cell death pathways within the precursors to muscle fibers, and during the crucial process of primary myogenesis, can exert an effect on diversification of muscle fiber types.
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  • 41
    ISSN: 1432-0533
    Keywords: Key words Parkinson’s disease ; Apoptosis ; Bcl-2 ; Bax ; Bcl-x
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract We studied the substantia nigra of three Parkinson’s disease (PD) patients and three age-matched individuals by in situ DNA-end labeling (ISEL) and immunohistochemistry for the apoptosis regulating proteins Bcl-2, Bax and Bcl-x on 50 consecutive sections per patient. No melanin-containing cell was identified with typical apoptotic changes in either patient or control substantia nigra. With prolonged reaction-time the terminal transferase-mediated DNA-end labeling revealed a signal in 2.0 ± 1.2% melanin-containing cells in PD compared to 1.3 ± 1.1% in control. This difference did nor reach statistical significance and no condensation or margination of the chromatin was evident. No significant changes of any of the apoptosis regulating proteins were apparent in PD substantia nigra. These findings do not support the hypothesis that apoptosis plays a central role in the pathogenesis of PD.
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  • 42
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    Acta neuropathologica 97 (1999), S. 279-287 
    ISSN: 1432-0533
    Keywords: Key words Canine distemper virus ; Oligodendrocytes ; Apoptosis ; Necrosis ; Demyelination
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Canine distemper virus (CDV) causes a multifocal demyelinating disease in dogs. It was previously shown that the initial demyelinating lesions are directly virus induced since a correlation between the occurrence of demyelination and CDV replication in white matter cells was observed. During the course of infection oligodendrocytes undergo distinct morphological alterations, partly due to a restricted CDV infection of these cells, and eventually disappear from the lesions. This phenomenon has been described in vivo as well as in vitro. However, the reason for the morphological alterations and the following oligodendroglial depletion remained unclear. Since virus infection can induce cell death, it was investigated whether apoptosis or necrosis plays a role in the pathogenesis of demyelination in canine distemper. In brain tissue sections from dogs with acute distemper apoptotic cells were not detected within the demyelinating lesions using morphological and biochemical cell death criteria. In chronic distemper, apoptotic cells – presumably inflammatory cells – were seen within the perivascular cuffs. These in vivo findings were correlated to the in vitro situation using CDV-infected primary dog brain cell cultures as well as Vero cells. Infection with culture-adapted CDV lead to massive necrosis but not to apoptosis. After infection with virulent CDV neither apoptosis nor necrosis was a predominant feature in either culture system. These findings suggest that virus-induced demyelination in canine distemper is not the direct consequence of apoptosis or necrosis. It is speculated that another mechanism must be responsible for the observed morphological alterations of oligodendrocytes, ultimately leading to demyelination.
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  • 43
    ISSN: 1432-0568
    Keywords: Key words Brain ; Cortical parcellation ; Development ; Proteoglycans ; Apoptosis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  Nitric oxide (NO) regulates several functions both in the developing and the adult central nervous systems (CNS). During development, NO is assumed to contribute to the histogenetic differentiation of the CNS especially through the modulation of programmed neuronal death. The embryonal and postnatal changes in the distribution of the cortical NO producing system were studied in Balb/c mice using immunocytochemistry for nitric oxide synthase-I (NOS-I) and NADPH-diaphorase (NADPH-d) enzyme histochemistry. NOS-I reactive neurons (RN) appeared first at embryonic day 14 (E14) in the spinal cord in the vicinity of the central canal, and later, at E16–18, in the thalamus and striatum. The first cortical region to present NOS-I reactivity was the parietal cortex, which happened at E18–20. After E20 the number of NOS-I RN increased in every cortical area, plateauing at postnatal day 4 (P4). In parietal regions, however, the highest density of NOS-I RN was observed already at P1. The neuronal packing density (PD) of NOS-I RN declined until adulthood, interrupted by a transient increase in some cortical areas at the onset of puberty. The heterochronous appearance of NOS-I during pre- and postnatal development of different brain regions and the sequence of up- and downregulation of expression until adult stages points to an important role of NO in brain development and functional differentiation.
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  • 44
    ISSN: 1432-0568
    Keywords: Key words Synaptogenesis ; Primate ; Spinal cord ; Apoptosis ; Neuropeptides
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  Development of glomerular synapses in the superficial dorsal horn has been studied in the embryonic macaque spinal cord using light and electron microscopic techniques including Golgi impregnation, 3H-thymidine radioautography and pre-embedding immunohistochemistry of substance P (SP), calcitonin gene related peptide (CGRP), calbindin D-28 K (CB) and parvalbumin (PV). The study revealed that substantia gelatinosa cells of the primate dorsal horn are generated last, but unlike in rodents, synaptogenesis in this region starts at early embryonic (E) stages of the 165-day long gestation. Already by E30, both Type 1 (light) and 2 (dark) dorsal root axons and their growth cones are identifiable within the oval bundle of His, before they form synaptic contact with their final target cells. Subsequently they invade the dorsal horn and enter the bisecting interfaces formed by orderly programmed cell death. Each type of scalloped (sinusoid) central primary afferent terminal (i.e. DSA, RSV and LDCV) have well defined pre- and post-synaptic specializations already by E40. Among the neuropeptides studied, SP appears first at E67 and CGRP at E70 in the lateral position but within a few days both of them are spread to the entire superficial dorsal horn. Both SP and CGRP are present in the thin dorsal root axons and their growth cones, giving rise to scalloped and simple axon terminals. PV is transiently present in the entire length of the thick dorsal root afferents before becoming concentrated in the synaptic boutons. CB is displayed mainly in neurons of the lamina I and III. Dendrites of CB-immunoreactive cells establish synaptic connection with each type of dorsal root afferents, including glomerular synaptic complexes. These data reveal that the superficial dorsal horn in the primate spinal cord develops its characteristic synaptic complexes much earlier in gestation than in any other mammalian species studied. Furthermore, characteristic cytological features of the prospective glomerular complex emerge before establishment of the final synaptic contacts.
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  • 45
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    Archives of dermatological research 291 (1999), S. 212-216 
    ISSN: 1432-069X
    Keywords: Key words UV irradiation ; Solar-simulated irradiation ; Apoptosis ; bcl-2 ; bax
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Recently, the proto-oncogenes bcl-2 and bax have emerged as important regulators of the apoptotic form of cell death. We examined UV irradiation-elicited apoptosis and regulation of bcl-2 and bax expression both in vivo in human skin and in vitro in HeLa cells. Using flow cytometric analysis, HeLa cells were found to undergo apoptosis at the 12-h time-point after exposure to UVB irradiation (100 mJ/cm2). The expression of bcl-2 mRNA was found to decrease after a single dose of UVB radiation (doses 10–200 mJ/ cm2). In contrast, the expression of bax mRNA was not significantly changed. When human skin was irradiated with a single dose of solar-simulated radiation (40 mJ/cm2), Bcl-2-positive cells were significantly reduced in the epidermis at the 3- and 6-h time-points. Our results suggest that UV irradiation downregulates bcl-2 expression both in vitro at the mRNA level and in vivo at the protein level, and that downregulation of bcl-2 constitutes a mechanism of potential importance in UV-induced apoptosis in human epidermis.
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  • 46
    ISSN: 1432-069X
    Keywords: Key words TUNEL ; Apoptosis ; Trichilemmal ; keratinization ; Epidermal appendages
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
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  • 47
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    Archives of dermatological research 291 (1999), S. 303-305 
    ISSN: 1432-069X
    Keywords: Key words Langerhans cells ; Sunburn cells ; UV ; erythema ; Apoptosis ; Immunohistochemistry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
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  • 48
    ISSN: 1432-069X
    Keywords: Key words Keratinocyte ; UVB ; Apoptosis ; Calcium ; p53
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Normal human keratinocytes are stimulated to proliferate in serum-free medium containing subphysiological concentrations of calcium (0.09 mM, low calcium). In this study, we examined the effect of increased levels of extracellular calcium (2.0 mM, normal calcium) on UVB-induced apoptosis. Apoptosis was assessed by changes in cellular morphology, annexind V-FITC flow cytometry, and the formation of internucleosomal DNA ladders. High doses of UVB induced keratinocytes grown in low calcium medium to undergo apoptosis. In contrast, keratinocytes grown for 72 h in normal calcium medium were completely resistant to UVB-induced apoptosis. No apoptosis was observed even at UVB doses as high as 1200 J/m2. However, despite the lack of UVB-induced cell death, keratinocytes grown in normal calcium medium lost the ability to proliferate following high levels of UVB irradiation. High doses of UVB also increased the expression of the differentiation-specific proteins involucrin and cytokeratin 10 in a dose-dependent manner. In addition, growth in normal calcium medium lowered the UVB-induced stimulation of the p53 protein and altered the normal subcellular localization pattern of p53. UVB irradiation of human keratinocytes grown in normal calcium medium may be inducing further cell differentiation in the absence of overt cell death.
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  • 49
    ISSN: 1432-0584
    Keywords: Key words IL-6 variants ; Cell cycle ; Apoptosis ; Multiple myeloma ; Cell line
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  Interleukin-6 (IL-6) serum levels and the proliferative activity of bone marrow plasma cells have been described as important prognostic factors for survival duration in multiple myeloma (MM) patients. Since growth of neoplastic plasma cells is frequently promoted by IL-6, inhibition of its activity has been considered for the management of MM patients. With a similar rationale, IL-6 variants characterized by wild-type or increased affinity for the ligand-specific IL-6 α receptor chain and reduced ability to bind and/or dimerize the gp 130 chain have recently been generated. In the present study, the antiproliferative effects of the variants Sant1, Sant5, and Sant7, characterized by increasing antagonistic activity, were investigated by means of a detailed cell kinetic and apoptotic analysis of the IL-6-dependent MM XG-1 cell line. A significant reduction in the mean percent of XG-1 cells in active S-phase (DNA/bromodeoxyuridine incorporation) from 41% to 28.1% (p=0.04), 25.8% (p=0.04), and 15.3% (p=0.02), respectively, was observed using Sant1, Sant5, and Sant7. These effects were confirmed using the acridine-orange (AO) flow-cytometric technique, which showed a similar reduction of S-phase (34.2% of baseline value) in the presence of Sant1, Sant5, and Sant7, as well as a significant G1b arrest (from 44.5% to 47.6%, 48%, and 64.9%). Furthermore, IL-6 variants were capable of down-regulating the G1 cell cycle regulatory protein cyclin D1 expression. Cell cycle effects were coupled with a significant increase of apoptosis, measured by the AO and the terminal deoxynucleotidyl transferase assays, from 12.9% (control culture with IL-6) to 21.2% (Sant1), 29.1% (Sant5), and 23.5% (Sant7). These results were comparable to those obtained by depriving XG-1 of recombinant IL-6. Our study documents the antiproliferative activity exerted by IL-6 mutants on the XG-1 cell line, thus supporting the investigation of these molecules on primary MM cells.
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  • 50
    ISSN: 1432-0584
    Keywords: Key words Idiopathic myelofibrosis ; PCNA labeling ; Apoptosis ; Dynamic disease features ; Prognosis ; Proportion of life loss ; Bone marrow
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  A retrospective study of 120 patients with the clinically and histologically established diagnosis of idiopathic (primary) myelofibrosis (IMF) was performed to determine prognostic factors of predictive value, including parameters characterizing the dynamics of hematopoietic cell kinetics. In contrast to previous studies, our cohort comprised the full spectrum of the disease, from initial prefibrotic to advanced osteosclerotic stages. The in situ end-labeling (ISEL) technique was used to demonstrate apoptosis, in order to determine dynamic parameters of predictive value. Cell proliferation was evaluated by employing the monoclonal antibody PC10 directed against proliferating cell nuclear antigen (PCNA). Proliferative activity (PCNA index) and frequency of apoptosis showed significant differences between early and advanced fibrosclerotic stages of disease. Decrease in proliferation indicated a significantly shorter survival, whereas a higher frequency of apoptotic cells was associated with a better prognosis. It may be speculated that a normal or enhanced proliferation rate expressed by PCNA positivity (late G1- and S-phase of the cell cycle) that is accompanied by a higher incidence of apoptosis reflects the regenerative (turnover) capacity of hematopoiesis. This may apply especially to early hypercellular stages without relevant myelofibrosis. In consideration of a recently published multivariate risk model, a simplified synthesis score for stratification of a patient's prognosis was constructed. Age, degree of anemia, leukocytes, and platelet count were regarded as the most important parameters. A substantial improvement of prognostic efficiency was further achieved by including PCNA index and frequency of apoptosis. Our results are in keeping with the assumption that generalization, indicated by myeloid metaplasia, has a prodigious impact on prognosis in IMF. Furthermore, in this context dynamic features such as proliferative activity and frequency of apoptosis exert an additional predictive value.
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  • 51
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    Diabetologia 42 (1999), S. 711-718 
    ISSN: 1432-0428
    Keywords: Keywords Malnutrition ; ageing ; beta-cell mass ; apoptosis ; glucose tolerance.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Aims/hypothesis. In a recently developed rat model, maternal food restriction from day 15 of pregnancy until weaning induced low birth weight and a 70 % reduction of beta-cell mass in the offspring at day 21 after birth. Subsequent renutrition from weaning was insufficient to fully restore beta-cell mass in young adult rats. The aim of this study is to investigate the long-term consequences of early malnutrition on beta-cell mass and function. Methods. Oral glucose tolerance tests were done in 3- and 12-month-old animals and beta-cell mass and apoptosis were determined by morphometrical measurements on pancreatic sections. The specific impact of postnatal malnutrition was studied by comparing control animals (C group) with animals malnourished during their fetal life only (R/C group), and animals malnourished during fetal life and until weaning (R group). Results. In 3-month-old R/C animals beta-cell mass reached 8.0 ± 1.5 mg with no further increase until 12 months (8.1 ± 1.5 mg), compared with 9.3 ± 1.9 mg in control rats. Twelve-month-old R/C animals showed normal plasma insulin responses and borderline glucose tolerance. In R animals, apoptosis reached 1.9 ± 0.4 % of the beta cells at 3 months, compared with 0.7 ± 0.5 % in control rats, and beta-cell mass did not increase between 3 and 12 months (4.7 ± 0.8 mg at 12 months). In aged control and R animals, apoptosis affected 8 % of the beta cells. At 12 months only, R animals showed profound insulinopenia and marked glucose intolerance. Conclusion/interpretation. In conclusion, perinatal malnutrition profoundly impairs the programming of beta-cell development. In animals with decreased beta-cell mass the additional demand placed by ageing on the beta cells entails glucose intolerance since beta-cell mass does not expand and apoptosis is increased. [Diabetologia (1999) 42: 711–718]
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  • 52
    ISSN: 1432-0428
    Keywords: Keywords Type I diabetes ; interferon-γ ; transgenic mice ; apoptosis ; insulin secretion ; tumour necrosis factor.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Aims/hypothesis. To examine whether interferon-γ destroys islet beta cells directly or indirectly through lymphocyte activation, or whether direct action of interferon-γ on beta cells by itself induces diabetes without insulitis. Methods. To avoid possible nonspecific breakdown of beta cells by transgenic overexpression of interferon-γ by the insulin promoter, we generated transgenic mice expressing interferon-γ under the control of rat glucagon promoter (RGP-IFN-γ-Tg mice). Results. The absence of insulitis in RGP-IFN-γ-Tg mice enabled us to investigate the direct effects of paracrine interferon-γ. In RGP-IFN-γ-Tg mice, serum concentrations of interferon-γ and tumour necrosis factor-α (TNF-α) were 50 and 6 times higher than those in their littermates, respectively, and glucose-responsive insulin secretion decreased to one-half the level of that in the littermates. Transgenic interferon-γ induced remodelling of beta cells where apoptosis of many beta cells was compensated by their vigorous regeneration and diabetes did not occur in most of the RGP-IFN-γ-Tg mice. Conclusion/interpretation. Interferon-γ alone is insufficient for the complete destruction of beta cells in vivo, and factors other than interferon-γ including activated lymphocytes or other cytokines, are necessary in addition to interferon-γ for the development of Type I (insulin-dependent) diabetes mellitus. [Diabetologia (1999) 42: 566–573]
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  • 53
    ISSN: 1423-0127
    Keywords: TNFα ; Fas ; FasL ; Apoptosis ; Cytokine
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract The CD3+/TCRαβ+ T-cell-mediated hepatic inflammation induced byPropionibacterium acnes could be divided into an acute and a chronic phase. The acute phase occurred within 72 h after injection and displayed hepatic apoptosis. Anti-TNFα antibody inhibited both theP. acnes-induced hepatic apoptosis and lymphocyte infiltration seen in this phase, indicating the involvement of this cytokine. Thereafter, a chronic phase was manifested from days 7 to 14 after injection. It was characterized as granulomatous inflammation admixed with apoptosis of infiltrating lymphocytes and some hepatocytes. Immunohistochemical staining showed that the infiltrating lymphocytes displayed TNFα, TNF type I receptor and a variety of cytokines including IL-1β, IL-4, IL-6, IL-10, IFNγ or IL-12. Interestingly, in naive mice, the arteries in the liver constitutively expressed IFNγ. Its expression appeared to be substantially increased at 48 h, decreased at 72 h, and increased again on day 14 afterP. acnes injection. Furthermore, Fas or FasL was only detected on the lymphocytes within the granuloma. We conclude thatP. acnes can induce a TNFα-mediated acute hepatic apoptosis which subsequently progress to a T-cell-mediated granulomatous hepatitis with increased expression of multiple cytokines and Fas/FasL.
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  • 54
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    Journal of biomedical science 6 (1999), S. 433-438 
    ISSN: 1423-0127
    Keywords: AIDS dementia complex ; Antioxidants ; Apoptosis ; Cerebral atrophy ; gp120 ; HIV-1 protease ; Human neuroblastoma cell ; Neuroprotection ; Protease inhibitor (KNI-272)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract A significant number of adult male patients with acquired immunodeficiency syndrome develop cerebral atrophy and progressive brain disorders such as dementia complex and neuropsychiatric problems. Upon entering the brain via activated macrophages or microglias, the human immunodeficiency type 1 virus (HIV-1) may produce cytotoxic factors such as HIV-1 envelope protein (gp 120) and protease. Owing to significant proteolysis of nonviral proteins, the protease derived from HIV-1 may be detrimental to brain cells and neurons. Our results revealed that HIV-1 protease, at nanomolar concentrations, was as potent as gp 120 in causing neurotoxicity in human neuroblastoma neurotypic SH-SY5Y cells. As shown by the Oncor ApopTag staining procedure, HIV-1 protease significantly increased the number of apoptotic cells over the serum-free controls. Moreover, HIV-1 protease-induced neurotoxicity was blocked by a selective protease inhibitor, kynostatin (KNI-272). Antioxidants such as 17β-estradiol, melatonin, andS-nitrosoglutathione also prevented protease-induced neurotoxicity. These findings indicate that oxidative proteolysis may mediate HIV-1 protease-induced apoptosis and the degeneration of neurons and other brain cells. Centrally active protease inhibitors and antioxidants may play an important role in preventing cerebral atrophy and associated dementia complex caused by HIV-1.
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  • 55
    ISSN: 1432-0428
    Keywords: Keywords Nicotinamide ; cytokine ; islet ; insulin ; apoptosis ; diabetes.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Nicotinamide intervention trials are presently undertaken to prevent Type I (insulin-dependent) diabetes in high risk subjects. They are based on studies in rodents reporting nicotinamide protection against beta-cell injury in vitro and in vivo. This study examines whether nicotinamide can protect human beta cells in vitro. At concentrations (2 and 5 mmol/l) to protect rat beta cells against necrosis by streptozotocin or hydrogen peroxide, nicotinamide prevents hydrogen peroxide-induced necrosis of human beta cells. As with rat beta cells, nicotinamide fails to protect human beta cells against apoptosis induced by a combination of the cytokines interleukin-1β , interferon-γ and tumour necrosis factor-α. In rat beta cells, nicotinamide (2 to 20 mmol/l) was also found to induce apoptosis, in particular during the days following its protection against necrosis; this cytotoxic effect was not observed with human beta cells. These data demonstrate that nicotinamide can protect human beta cells against radical-induced necrosis, but not against cytokine-induced apoptosis. This effect is not associated with a delayed apoptosis as in rat beta cells. [Diabetologia (1999) 42: 55–59]
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  • 56
    ISSN: 1279-8509
    Keywords: p53 ; Apoptosis ; PKC ; g-irradiation ; Transcription
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Several mutations prevent the expression of p53 in the human lymphoblastoid T cell line Jurkat. Restoration of p53 in Jurkat cells had no effect on the cell growth but markedly increased the amount of apoptosis induced by g-irradiation. Inhibition of RNA synthesis using 5,6-dichlorobenimidizole riboside had little effect on apoptosis induced by irradiation in the presence of p53 and did not affect the p53-independent apoptotic pathway. Expression of p53 also had no effect on the expression levels of proteins such as Fas, GADD45, Bax, Bcl-2, Bcl-xL or p53 induced proteins (PIGS) in resting cells or after irradiation. Activation of protein kinase C by phorbol 12-myristate 13-acetate produced an almost complete inhibition of p53-independent apoptosis following irradiation, whereas no significant effect was observed on the rate of p53-induced apoptosis. Although phorbol 12-myristate 13-acetate strongly induced p21 and stabilised p53 in the resting transfected Jurkat cells, neither apoptosis nor cell arrest was observed. In summary, this work shows that p53 enhances the radiosensitivity of Jurkat cells through an apoptotic process that is triggered by irradiation and is largely independent of RNA synthesis and protein kinase C activation. Apoptosis in p53- negative Jurkat cells is strongly inhibited by PMA indicating that the pathway triggered by p53 may be distinct from apoptotic pathways used in its absence.
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  • 57
    ISSN: 1423-0127
    Keywords: Autoimmunity ; Apoptosis ; IL-2 ; FasL ; Tolerance
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract Studies of several gene knockout mice suggest an interesting association of a moderate T cell response with systemic autoimmune diseases. In addition, CD95 ligand (FasL) expression in some strains of these mice is impaired. Because FasL is critically involved in regulating peripheral tolerance, there may be a link between autoimmune diseases and a moderate T cell response that cannot activate the FasL gene. Here, we propose that there are two thresholds of T cell activation. When moderately stimulated, T cells can be activated to the low (1st) threshold, which permits the induction of CD40L, IL-2, IL-4, and other components that help the immune response. The high (2nd) activation threshold can only be achieved by a strong and concurrent stimulation through TCR and IL-2R. Once the high threshold is reached, FasL is produced to induce apoptosis of the activated T and B cells. In the absence of the FasL-mediated downregulation, the activated B cells become efficient antigen-presenting cells for self-antigens and excellent responders for T cell help. Such an exacerbating condition, induced by recurrent and moderate activation, favors the development of autoreactive T cells and autoantibody production. Evidence supporting this hypothesis and some predictions that can be tested are described.
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  • 58
    ISSN: 1423-0127
    Keywords: Glioma ; Apoptosis ; Vandate ; Akt ; PKB
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract The dual signal hypothesis of apoptosis holds that a common signal can activate both apoptotic and proliferative pathways. The fate of a cell is dependent on which of these two pathways predominates. In the MAPK family of kinases, ERK and JNK have been proposed to mediate apoptosis whereas the PI3K-stimulated kinase, Akt/PKB, has been shown to inhibit apoptosis. The object of this study was to determine the role of these kinases in a glioma model of apoptosis. We have previously shown that K252a induces apoptosis and inhibits kinase activity. In this study we confirm these results and shown that the protein tyrosine phosphatase inhibitor sodium vanadate activates ERK, JNK and Akt/PKB, but does not stimulate proliferation. Vanadate did protect T98G cells from K252a-induced apoptosis, an effect that was abolished by addition of the PI3K inhibitor wortmannin. This suggests that PI3K and Akt/PKB may be responsible for mediating vanadate's protective effect on glioma cells. We conclude that the intracellular balance between protein phosphorylation pathways is a critical determinant of both cell proliferation and cell death.
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  • 59
    ISSN: 1432-0843
    Keywords: Key words Cyclin-dependent kinase ; Cytotoxicity ; Apoptosis ; Multidrug resistance
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Purpose: To determine the in vitro effects of flavopiridol on bladder cancer cell lines, immortalized urothelial cell lines, and normal urothelial cells well characterized for defects in p53, pRb, and p16. Methods: Growth inhibition was assessed via an MTT assay and apoptosis via DAPI nuclear staining. Cell cycle analysis was performed via propidium iodide staining and fluorescent activated cell sorting (FACS). Multidrug-resistant cells were generated by continuous exposure to doxorubicin. Results: Growth inhibition was not correlated with inactivation of p53, pRb, or p16. All cells experienced G2/M arrest within 24 h of flavopiridol exposure. Modest apoptosis was observed but required 72 h of continuous drug exposure to become evident. There was no obvious synergistic or antagonistic toxicity when flavopiridol was combined with radiotherapy or cisplatin dosed at the IC50 despite the observation that radiotherapy and flavopiridol led to more profound G2/M arrest than either agent alone. Doxorubicin-resistant cells, demonstrated to overexpress the MDR1 multidrug-resistance protein were equally as sensitive to flavopiridol as the parental cells. Conclusions: Flavopiridol is a novel cell cycle inhibitor that may be a useful agent in bladder cancers with tumor suppressor gene alterations and/or multidrug resistance.
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  • 60
    ISSN: 1432-0843
    Keywords: Key words Dolastatin ; Lung cancer ; Apoptosis ; Xenografts ; Experimental therapeutics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Purpose: Dolastatin 10 is a natural cytotoxic peptide which acts through the inhibition of microtubule assembly. Studies have suggested that such agents can induce apoptosis in association with bcl-2 phosphorylation. Since bcl-2 overexpression is common in small-cell lung cancer (SCLC), we evaluated the activity of dolastatin 10 in SCLC cell lines and xenografts. Methods: In vitro growth inhibition was evaluated with a standardized MTT assay and apoptosis with fluorescent microscopy and a TUNEL assay. Immunoblot analysis and phosphatase digestion were used to determine bcl-2 modification. In vivo activity was evaluated in subcutaneous and metastatic SCLC xenograft models in SCID mice. Results: Dolastatin 10 had growth inhibitory activity against four SCLC cell lines (NCI-H69, -H82, -H446, -H510) with IC50 values ranging from 0.032 to 0.184 nM. All four cell lines exhibited evidence of apoptosis after 48 h of exposure to 1.3 nM dolastatin 10. Immunoblot analysis revealed that 1.3 nM dolastatin 10 altered the electrophoretic mobility of bcl-2 in NCI-H69 and -H510 cells within 16 h of treatment. Incubation of protein extract from dolastatin 10-treated NCI-H69 and -H510 cells with calcineurin resulted in the disappearance of the altered mobility species, suggesting dolastatin 10-induced bcl-2 phosphorylation. In in vivo studies, 450 μg/kg of dolastatin 10 IV × 2 given after intravenous injection of NCI-H446 cells completely inhibited tumor formation. In established subcutaneous NCI-H446 xenografts, 450 μg/kg of dolastatin 10 IV induced apoptosis in the majority of tumor cells within 96 h, resulting in a log10 cell kill of 5.2 and an increase in median survival from 42 to 91 days. Conclusions: These findings suggest that dolastatin 10 has potent activity against SCLC and that the modulation of apoptotic pathways deserves further evaluation as an anticancer strategy.
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  • 61
    ISSN: 1432-0843
    Keywords: Key words Baccatin III ; Paclitaxel ; Apoptosis ; Mitotic arrest ; bcl-2
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Purpose: Paclitaxel has been demonstrated to possess significant cell-killing activity in a variety of tumor cells by induction of apoptosis, but the mechanism by which paclitaxel leads to cell death and its relationship with mitotic arrest is not entirely clear. In this study, baccatin III, a synthetic precursor of paclitaxel, was used to analyze whether paclitaxel-induced apoptosis can be a separate event from microtubule bundling and G2/M arrest. Methods: Several different methods including DNA fragmentation, flow cytometric analyses, TdT-mediated dUTP nick end labeling (TUNEL) and time-lapse video microscopy were used to analyze apoptotic cell death induced by baccatin III and its possible correlation with cell cycle distribution. Results: Our results demonstrated that baccatin III could also cause apoptotic cell death in both BCap37 (a human breast cancer cell line) and KB cells (derived from human epidermoid carcinoma), but had less effect on microtubule bundling and G2/M arrest. Furthermore, we demonstrated that most apoptotic events induced by baccatin III were not coupled with G2/M arrest. Instead, these apoptotic events occurred predominantly in the cells in other phases of the cell cycle. Conclusion: Baccatin III, which contains the core taxane ring, is the fundamental piece of paclitaxel structure. The finding of baccatin III-induced apoptosis independent of cell cycle arrest, on the one hand, implies that the core taxane ring may play a critical role in inducing cell death and, on the other hand, suggests that paclitaxel might induce apoptosis from other phases of the cell cycle by a similar mechanism.
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  • 62
    ISSN: 1432-0851
    Keywords: Key words Immunotherapy ; MK-1 antigen ; Chimeric antibody ; ADCC ; Apoptosis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Mouse monoclonal antibody FU-MK-1, raised against a human gastric adenocarcinoma, recognizes a glycoprotein antigen (termed MK-1 antigen) present on most carcinomas and seems to be valuable in immunodiagnosis and immunotherapy of various cancers. In a recent study, we constructed a mouse/human chimeric antibody, designated Ch FU-MK-1, by fusing the FU-MK-1 VH and Vκ genes to the human Cγ1 and Cκ genes, respectively. In the present study, we tested combination immunotherapy of Ch FU-MK-1 with human lymphokine-activated killer (LAK) cells in vitro and in mice with severe combined immunodeficiency (SCID) bearing human MK-1-expressing tumors. In in vitro experiments, Ch FU-MK-1 effectively mediated antibody-dependent cell-mediated cytotoxicity (ADCC) against MK-1-expressing MKN-74 cells, which was completely blocked by an anti-FcR antibody. Since the apoptotic pathway as well as the necrotic pathway have been shown to be utilized in various cytotoxic effector mechanisms, we investigated the role of apoptosis in ADCC mediated by LAK cells and Ch FU-MK-1 against MKN-74 cells. The implication of the apoptosis during ADCC was demonstrated by means of both a terminal-deoxynucleotidyltransferase-mediated dUTP-biotin nick-end-labeling assay and a propidium iodide staining method. In vivo antitumor activity of combination treatment with LAK cells and Ch FU-MK-1 was estimated using SCID mice inoculated s.c. with MKN-74 cells. The i.v. administration of LAK cells and i.p. administration of Ch FU-MK-1 and interleukin-2 (IL-2) produced a marked growth inhibition of MKN-74 tumors in SCID mice. When the actual tumor weights were measured 16 days after initiation of treatment, more than 70% reduction was observed in the group receiving LAK cells plus Ch FU-MK-1 plus IL-2 as compared to the control untreated group. Together these results suggest that Ch FU-MK-1 may serve as a potentially useful immunotherapeutic reagent for human MK-1-expressing tumors.
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  • 63
    Electronic Resource
    Electronic Resource
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    International journal of colorectal disease 14 (1999), S. 201-211 
    ISSN: 1432-1262
    Keywords: Key words Inflammatory bowel disease ; TNBS rat model ; Resistant starch ; Absorption of short-chain fatty acids ; Butyrate functions ; Proliferation ; Apoptosis ; Matrix proteins ; Intestinal microflora
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  These studies were performed to test the benefit of resistant starch on ulcerative colitis via prebiotic and butyrate effects. Butyrate, propionate, and acetate are produced in the colon of mammals as a result of microbial fermentation of resistant starch and other dietary fibers. Butyrate plays an important role in the colonic mucosal growth and epithelial proliferation. A reduction in the colonic butyrate level induces chronic mucosal atrophy. Short-chain fatty acid enemas increase mucosal generation, crypt length, and DNA content of the colonocytes. They also ameliorate symptoms of ulcerative colitis in human patients and rats injected with trinitrobenzene sulfonic acid (TNBS). Butyrate, and also to a lesser degree propionate, are substrates for the aerobic energy metabolism, and trophic factors of the colonocytes. Adverse butyrate effects occur in normal and neoplastic colonic cells. In normal cells, butyrate induces proliferation at the crypt base, while inhibiting proliferation at the crypt surface. In neoplastic cells, butyrate inhibits DNA synthesis and arrests cell growth in the G1 phase of the cell cycle. The improvement of the TNBS-induced colonic inflammation occurred earlier in the resistant starch (RS)-fed rats than in the RS-free group. This benefit coincided with activation of colonic epithelial cell proliferation and the subsequent restoration of apoptosis. The noncollagenous basement membrane protein laminin was regenerated initially in the RS-fed group, demonstrating what could be a considered lower damage to the intestinal barrier function. The calculation of intestinal short-chain fatty acid absorption confirmed this conclusion. The uptake of short-chain fatty acids in the colon is strongly inhibited in the RS-free group, but only slightly reduced in the animals fed with RS. Additionally, RS enhanced the growth of intestinal bacteria assumed to promote health. Further studies involving patients suffering from ulcerative colitis are necessary to determine the importance of RS in the therapy of a number of intestinal diseases and the maintenance of health.
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  • 64
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    Experimental brain research 124 (1999), S. 241-247 
    ISSN: 1432-1106
    Keywords: Key words Melatonin ; Kainate ; Glutathione ; Apoptosis ; Excitotoxicity
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  The anti-excitotoxic efficacy of the pineal hormone melatonin was investigated in kainate-injured brains of rats. Kainate (a glutamate-receptor agonist, 2.5 nmol in 1 µl) was directly injected to unilateral striatum. Melatonin (10 mg/kg) was administrated intraperitoneally 1 h before and 1, 3, and 5 h after intrastriatal kainate injection in adult Sprague-Dawley rats. Three days after kainate injection, a significant neuronal damage was found, as determined by Nissl staining and the TUNEL method, not only in the injected striatum, but also in the ipsilateral neighboring cortex. The kainate-induced cortical apoptotic neuronal death was significantly attenuated by treatment with melatonin compared with the vehicle control group. However, no detectable changes were observed in the contralateral side of the brain in either vehicle- or melatonin-treated rats. Moreover, the biochemical results indicated that kainate can indeed induce oxidative stress, such as a decrease in the content of total glutathione (GSH), oxidized glutathione (GSSG), and an increase in the ratio of GSSG/GSH in the striatum and cortex compared with the contralateral brain regions. In the kainate-injected striatum, melatonin did not reduce the oxidative stress, but in the neighborhood of injected area-cortex, kainate-induced oxidative stress was significantly reduced by melatonin. Enhancement of glutathione-peroxidase activity was induced by intrastriatal kainate injection, not only in the cortical area of control and melatonin-treated rats, but also in striatum of control rats. However, a large elevation was found in the melatonin-treated cortex. Taking the morphological and biochemical data together, the present results suggest that melatonin functions as an antioxidant by upregulating the glutathione antioxidative defense system, thereby reducing neuronal death caused by excitotoxicity and preventing the kainate-induced damage from spreading to adjacent brain regions.
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  • 65
    Electronic Resource
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    Naunyn-Schmiedeberg's archives of pharmacology 359 (1999), S. 228-234 
    ISSN: 1432-1912
    Keywords: Key words Natural killer ; Pentoxifylline ; Macroangiopathic patients ; Apoptosis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The methylxanthine derivative pentoxifylline, widely used in the treatment of vascular diseases, also has numerous immunological effects. In in vitro experiments, the human natural killer cell cytotoxicity was investigated in the presence of pentoxifylline. A clinical trial involved an investigation of the natural killer cell activity in patients to whom pentoxifylline had been administered for different periods. The natural cytotoxicity in macroangiopathic patients treated with pentoxifylline was compared with that in healthy controls and that in patients with vascular diseases who did not receive pentoxifylline therapy. A total of 62 macroangiopathic patients and 20 healthy controls were investigated. The natural killer cell activity in patients receiving pentoxifylline therapy for more than a year proved to be significantly lower (P〈0.005). The presence of vascular disease did not influence the natural killer activity. In the in vitro cytotoxicity reaction, pentoxifylline at a concentration of 100 µg/ml was found to suppress the natural killer cell cytotoxicity at any stage of the reaction. The influence of pentoxifylline on the natural killer cell activity was not due to inhibition of the expression of intercellular adhesion molecule-1. However, this drug significantly decreases (P〈0.05) the apoptosis of target cells. It is presumed that the suppressor effect of pentoxifylline on natural killer cell activity should be taken into consideration in the treatment of clinical diseases where this drug is administered chronically.
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  • 66
    ISSN: 1432-1963
    Keywords: Schlüsselwörter Epitheloides Hämangioendotheliom ; Leber ; Kindesalter ; Proliferation ; Apoptose ; Key words Epithelioid hemangioendothelioma ; Liver ; Childhood ; Proliferation ; Apoptosis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Summary We report on a 12-year old boy suffering from malignant epithelioid hemangioendothelioma of the liver, which is a very rare tumor in childhood. The tumor was detected by ultrasound examination at the age of 10 and appeared at that time as a solitary intrahepatic nodular lesion. During the following 2 years multiple nodular lesions developed in both hepatic lobes. There were neither any suspect anamnestic findings nor abnormal clinical or laboratory data. The tumor showed the typical histomorphological, immunohistochemical, and ultrastructural features of this entity, which is usually seen in older patients. We investigated proliferative activity, apoptotic regulation, and expression of VEGF and VEGF-receptor flk-1 by means of immunohistochemical techniques. According to the known slow growth activity of these tumors we found only a few Ki-67 positive tumor cells. We did not detect any apoptotic cells using TUNEL technique. The positive immunoreaction of the tumor cells with antibodies against VEGF and VEGF-receptor flk-1 may indicate the regulation of tumor growth by angiogenetic factors. We present our findings together with a summary of the most important publications of recent years concerning these tumors.
    Notes: Zusammenfassung Bei einem 12 Jahre alten Jungen wurde ein im Kindesalter sehr seltenes malignes epitheloides Hämangioendotheliom der Leber diagnostiziert. Im Alter von 10 Jahren fiel erstmals sonografisch ein solitärer Leberrundherd auf, im Verlauf der nächsten zwei Jahre entwickelten sich multiple Rundherde in beiden Leberlappen. Die Anamnese des Patienten war hinsichtlich möglicher prädisponierender Faktoren unauffällig. Die klinischen und laborchemischen Parameter befanden sich im Normbereich. Der Tumor wies die für diese, üblicherweise bei Erwachsenen auftretenden Entität typischen histomorphologischen, immunhistochemischen und ultrastrukturellen Merkmale auf. Mittels immunhistochemischer Untersuchungen wurde das Tumorgewebe hinsichtlich Proliferationsaktivität, Apoptoseregulation und Expression angiogenetischer Faktoren (VEGF und VEGF-Rezeptor flk-1) untersucht. Bei bekanntermaßen langsamer Wachstumstendenz dieser Tumoren fand sich ein geringer Anteil Ki-67-positiver Tumorzellen. Mittels TUNEL-Technik wurden keine Apoptosen gefunden. Die positive Immunreaktion der Tumorzellen mit Antikörpern gegen VEGF und den VEGF-Rezeptor flk-1 deutet auf eine Regulation des Tumorwachstums durch angiogenetische Faktoren hin. Die Ergebnisse werden in Verbindung mit einer Zusammenstellung der wichtigsten Publikationen der letzten Jahre über diese seltenen Tumoren diskutiert.
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  • 67
    ISSN: 1432-0983
    Keywords: Key words Fission yeast ; Caspases ; Bcl-2 ; Apoptosis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Two pro-apoptotic proteases, caspase-1 and caspase-3, have been expressed as full-length proteins in the fission yeast Schizosaccharomyces pombe. Both proteins autoprocess to generate the corresponding active enzyme and both are lethal to the yeast cell. Lethality is due to catalytic activity since the expression of the inactive mutant forms of both caspases does not result in an obvious phenotype. Caspase-expressing yeast can be rescued by co-expression of the baculovirus protein p35, a known inhibitor of the caspase family. Co-expression of Bcl-2, another anti-apoptotic protein, does not prevent the cell death induced by either caspase. However, Bcl-2 is itself cleaved by both caspase-1 and caspase-3 at two adjacent recognition sites, YEWD31′A and DAGD34′V respectively, immediately downstream from the N-terminal BH4 domain, a region of Bcl-2 which is essential for its anti-apoptotic activity; similar cleavage of Bcl-2 by caspases has been demonstrated in mammalian cells. Hence, key elements of the apoptotic pathway can be reliably reconstituted in fission yeast, opening the way to exploit yeast in order to study the control of apoptosis. Furthermore, the activity of caspase-3, although not caspase-1, can be demonstrated in vitro using chromogenic substrates. This offers the possibility of using caspase-producing strains of yeast to screen for chemical inhibitors either in vivo or in vitro.
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  • 68
    ISSN: 1432-0851
    Keywords: Key words NK cells ; IL-2 ; Fas ; FasL ; Apoptosis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The Fas/Fas-ligand (FasL) system seems to play a key role in regulating immunoresponses. Highly purified CD56+CD3− natural killer (NK) cells were found to be resistant to the apoptosis-inducing Fas mAb CH11 in the absence or in the presence of interleukin-2 (IL-2) for up to 3 days. However, NK cells activated with IL-2 for 3 days became apoptotic following combined treatment with CH11 and actinomycin D, suggesting the presence of an intact apoptotic machinery. In contrast, NK cells cultivated in IL-2 for 6 days became sensitive to CH11-induced apoptosis without addition of actinomycin D. At this time, a pronounced up-regulation of the Fas protein on the NK cell membrane was detected. By using reverse transcription/polymerase chain reaction it was found that the anti-apoptotic gene FLIP was strongly expressed in NK cells for up to 6 days of IL-2 stimulation. After day 6, a time-dependent decrease in the expression of FLIP was observed concomitantly with increased sensitivity for Fas-mediated apoptosis. The amount of apoptotic and necrotic NK cells in the presence of IL-2 increased in a time-dependent manner, reaching 40% at day 6 of culture. The amount of apoptotic and necrotic NK cells was reduced in the presence of Fas-Fc protein. In addition, IL-2 stimulated the NK cells to release soluble FasL in a time-dependent manner, whereas membrane FasL did not seem to increase in a similar manner. These results indicate that Fas/FasL interactions are involved in the down-regulation of IL-2-activated human NK cells.
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  • 69
    ISSN: 1432-0851
    Keywords: Key words Tumour antigen ; MUC1 ; T cell ; immunosuppression ; Apoptosis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The in vitro anti-proliferative properties of various supernatants from MUC1-expressing cell lines and of purified preparations of MUC1 were evaluated. We have observed that supernatants from the MUC1- and MUC3-positive cell line T47D, but not from the MUC1- and MUC4-positive cell line MCF7, were able to inhibit proliferation of cells from various haematopoietic cell lines. Although the activity of T47D supernatants could be abrogated by immunodepletion of MUC1, immunopurified MUC1 from T47D was unable to inhibit cell proliferation. Significantly, supernatants from mouse 3T3 cells transfected with a secreted form of MUC1 or from BHK-21 cells infected with a recombinant vaccinia virus coding for the secreted form of MUC1, as well as preparations of purified MUC1 from bile or urine, were likewise unable to inhibit T cell proliferation. Surprisingly, a crude mixture of bile mucins had a suppressive effect on T cell growth. Our results suggest that other molecules, such as amino sugars or other mucins, which can associate with MUC1, are likely to be responsible for the observed anti-proliferative effects of T47D cells.
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  • 70
    ISSN: 1432-0851
    Keywords: Key words CD95L ; FasL ; Renca ; Apoptosis ; Tumor growth
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The CD95/CD95 ligand (CD95L) system plays an important role in the induction of lymphoid apoptosis and has been implicated in the suppression of immune responses. In this system, two murine CD95L-transfected renca clones and a control renca clone transfected only with the vector were implanted into the subcapsule of the left kidney of Balb/c and Balb/c nude mice. Both CD95L-expressing and control renca clones formed macroscopic tumors in all of the Balb/c and Balb/c nude hosts 14 days after implantation. Growth of tumors of murine CD95L-transfected renca cells was significantly better than that of control renca cells in Balb/c mice, while the growth advantage of CD95L transfectants was not observed in Balb/c nude mice. Lymphocytes underwent apoptosis mainly in the periphery of the CD95L-expressing tumors but not in control tumors grown in Balb/c mice, while lymphocytes undergoing apoptosis were not observed in CD95L-expressing tumors or in control tumors grown in Balb/c nude mice. Neutrophilic recruitment was rarely observed in CD95L-expressing or control tumors. CD95L expressed on renca cells possibly suppressed immune responses against renca tumors by inducing apoptosis of the infiltrating lymphocytes. However, CD95L-expressing renca cells did not form tumors in the renal subcapsule of allogeneic C3H/HeJ mice.
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  • 71
    ISSN: 1432-0738
    Keywords: Key words Doxorubicin ; Apoptosis ; Testicular toxicity
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract To clarify whether apoptosis is involved in doxorubicin (DXR)-induced testicular toxicity and to identify the target germ cell type, adult Sprague-Dawley rats were treated with a single intravenous dose of DXR (8 or 12 mg/kg) and euthanized at 3, 6, 12, 24, and 48 h subsequently. Histologically, germ cell degeneration was first found 6 h after dosing in meiotically dividing spermatocytes and early round spermatids of seminiferous tubules at stage I, and subsequently observed in spermatogonia at stages I–VI showing ultrastructural characteristics of apoptosis. Coincident with the appearance of morphological changes, degenerating germ cells were shown to be undergoing apoptosis as revealed by in situ terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL). The frequency of TUNEL-labeled germ cells increased in a stage- and cell type-specific manner, the peak of frequency gradually progressing from stage I of seminiferous tubules to later stages with time after dosing, suggesting that the damaged germ cells, especially spermatogonia, gradually underwent the processes leading to apoptosis. DNA laddering on gel electrophoresis was apparent 24 and 48 h after dosing. The results demonstrate that apoptosis plays an important role in the induction of testicular toxicity caused by DXR with meiotically dividing spermatocytes and type A and intermediate spermatogonia as highly vulnerable target cells.
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  • 72
    ISSN: 1432-0738
    Keywords: Key words Allylnitrile ; Apoptosis ; Behavioral abnormalities ; Habenula ; Mice brain
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract A single dose of allylnitrile in mice might induce persistent behavioral abnormalities, of which the mechanism is not yet known. The present study was undertaken to explore the relationship between behavioral abnormalities and pathological changes in the brain of mice following exposure to allylnitrile. Exposure to allylnitrile (63, 84, and 112 mg/kg, p.o.) resulted in dose-dependent changes in behavioral abnormalities, including increased locomotor activity, circling, retropulsion, head twitching, and alteration in reflexive behavior, which appeared at day 2 postdosing and were persistent throughout the experimental period (60 days) at the higher dose levels. Allylnitrile produced neuronal retraction including hyperchromasia of the nuclei in the raphe nuclei, cerebral cortex, hypothalamus, hippocampal CA1 and dentate gyrus later than 30 days. No gliosis was observed in these regions. Not all but a significant number of neurons in the hippocampal CA1, medial habenula and raphe nuclei were immunoreactive to CPP32 (Caspase-3) even at day 2. These neurons were also positive to Hoechst 33258 staining, indicating allylnitrile caused apoptotic changes in specific neurons when neuronal behaviors became apparent. These apoptotic changes were persistent even in the area without neuronal contraction such as medial habenula. However, almost all neurons in these areas were also positive to terminal deoxynucleotidyl transferase mediated dUTP-biotin nick end labeling (TUNEL). It is conceivable that allylnitrile caused apoptotic changes in neurons but did not always lead them to cell death immediately. Moreover, even when neuronal contraction resulted in retention of behavioral abnormalities, onset of these abnormalities seems to be associated with the impairment in the habenulo-raphe relay due to activation of apoptotic cascade in neurons.
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  • 73
    ISSN: 1432-1831
    Keywords: Key words Verocytotoxin ; Verocytotoxin-producing Escherichia coli ; Hemolytic uremic syndrome ; Renal proximal tubular cell ; Apoptosis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Verocytotoxin 1 and 2 (VT1 and 2) produced by verocytotoxin-producing Escherichia coli have been considered to play an important role in the pathogenesis of glomerular and tubular damage in the epidemic form of hemolytic uremic syndrome (HUS). VTs are known to be cytotoxic to culture cells by inhibiting cellular protein synthesis. In this in vitro study, the mechanism(s) of tubular damage in HUS and the ability of VT1 to induce apoptosis in normal human renal proximal tubular epithelial cells (HRPTEC) were examined. VT1 markedly reduced cell viability of HRPTEC and rapidly inhibited overall protein synthesis. VT1 directly induced apoptotic cell death in HRPTEC in a dose- and time-dependent fashion, and co-incubation with tumor necrosis factor-α enhanced the VT1-induced apoptosis. These results suggest that apoptosis induced by VT1, possibly in concert with host cytokines, in renal tubular cells may contribute to the tubular damage in HUS.
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  • 74
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    Annals of oncology 10 (1999), S. 139-150 
    ISSN: 1569-8041
    Keywords: apoptosis ; chemotherapy ; clinical trials ; gene therapy ; p53
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Nearly twenty years after the initial discovery of p53, we are now in an ideal position to exploit our vast knowledge of p53 biology in the creation of novel cancer therapies. Disruption of p53 function through mutation, or other means, occurs very frequently in human cancer. Loss of p53 function has been linked with unfavourable prognosis in a large number of tumour types, as indicated by more aggressive tumours, early metastasis and decreased survival rates. Many different avenues of research have converged upon p53 to highlight this protein as being one of the foremost cellular responders to stress, in particular to DNA damage. Huge advances have been made in understanding the complex role p53 plays in the regulation of apoptosis and cell cycle arrest. This review is not meant to be a comprehensive description of p53 biology, but rather serves to highlight current progress in the development of p53- oriented cancer therapies. These may be categorised into three basic strategies: gene replacement therapy using wild-type p53, restoration of p53 function by other means and, finally, targeting of the p53 dysfunction itself. Rapid progress is expected to be made regarding the identification of conventional pharmaceutical agents which either work in a p53-independent manner or act preferentially in p53 defective cells. Gene replacement therapy with wild-type p53 also holds considerable potential for obtaining clinically relevant results quickly. The other forms of cancer therapies based around p53 are much further behind in the developmental process, but may prove to more efficacious in the long run, especially in terms of specificity. As with many other fields, the innovation of successful p53-oriented cancer therapies is only limited by our understanding of p53 biology and the creative use of such knowledge.
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  • 75
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    Annals of oncology 10 (1999), S. 122-126 
    ISSN: 1569-8041
    Keywords: apoptosis ; biliary carcinogenesis ; cholangiocarcinoma ; genotoxicity ; risk factors ; therapeutic strategies
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Carcinomas of the biliary tract are rare cancers developing from the epithelial or blast-like cells lining the bile ducts. A variety of known predisposing factors and recent experimental models of biliary carcinogenesis (e.g., infection with the liver fluke Opisthorchis viverrini, models of chemically induced carcinogenesis and experimental models of pancreaticobiliary maljunction) have elucidated different stages of this complex system of biliary tumorigenesis. Chronic inflammatory processes, generation of active oxygen radicals, altered cellular detoxification mechanisms, activation of oncogenes, functional loss of tumor-suppressor genes and dysregulation of cell proliferation and cell apoptotic mechanisms have been identified as important contributors in the development of cholangiocarcinomas. In this review, the known mechanisms involved in the carcinogenesis of biliary epithelium are addressed. We will divide the topic into four stages: 1) Predisposition and risk factors of biliary cancer, 2) Genotoxic events and alterations leading to specific DNA damage and mutation patterns. 3) Dysregulation of DNA repair mechanisms and apoptosis, permitting survival of mutated cells and 4) Morphological evolution from premalignant biliary lesions to cholangiocarcinoma. Finally, established and hypothetical future therapeutic strategies directed towards specific pathogenetic events during biliary carcinogenesis will be addressed.
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  • 76
    ISSN: 1569-8041
    Keywords: acute myelogenous leukemia ; apoptosis ; ara-CTP ; cytosine arabinoside ; HL-60 ; retinoic acid
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Background: Accumulation of the cytosine arabinoside (ara-C) metabolite ara-C-triphosphate (ara-CTP) in leukemic blast cells is considered to be the main determinant of ara-C cytotoxicity in vitro and in vivo. Retinoids such as all-trans-retinoic acid (ATRA) have been shown to increase the sensitivity of acute myelogenous leukemic (AML) blast cells to ara-C. To investigate the mechanism of this sensitisation, the hypothesis was tested that ATRA augments cellular ara-CTP levels in human-derived myelogenous leukemia HL-60 cells. Materials and methods: The effect of ATRA and 13-cis-retinoic acid on ara-CTP accumulation and ara-C-induced apoptosis was studied. Ara-CTP levels were measured by high-performance liquid chromatography (HPLC), cytotoxicity by the tetrazolium (MTT) assay, and apoptosis by occurrence of DNA fragmentation (gel electrophoresis), cell shrinkage and DNA loss (flow cytometry). Results: Pretreatment of HL-60 cells with ATRA (0.01–1 µM) caused a significant decrease in intracellular ara-CTP levels; e.g., incubation for 72 hours with ATRA 1 µM prior to one hour ara-C 10 µM reduced ara-CTP levels to 41% ± 4% of control. Similar results were obtained after preincubation with 13-cis-retinoic acid. In spite of decreased ara-CTP levels, the cytotoxicity of the combination was supraadditive and ATRA augmented ara-C-induced apoptosis. Conclusions: At therapeutically relevant concentrations ATRA increased ara-C cytotoxicity and ara-C induced apoptosis but this augmentation is not the corollary of elevated ara-CTP levels. The feasibility of ara-C treatment optimisation via strategies other than those involving elevation of ara-CTP levels should be investigated further.
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  • 77
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    Molecular and cellular biochemistry 196 (1999), S. 13-21 
    ISSN: 1573-4919
    Keywords: apoptosis ; DNA fragmentation ; GSHPx-1 knockout mice ; GSHPx-1 transgenic mice ; ischemia/repurfusion
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Abstract Apoptosis, a genetically controlled programmed cell death, has been found to play a role in ischemic reperfusion injury in several animal species including rats and rabbits. To examine whether this is also true for other animals, an isolated perfused mouse heart was subjected to 30 min of ischemia followed by 2 h of reperfusion. Experiments were terminated before ischemia (baseline), after ischemia, and at 30, 60, 90 and 120 min of reperfusion. At the end of each experiment, hearts were processed for the evaluation of apoptosis and DNA laddering. The in situ end labeling (ISEL) technique was used to detect apoptotic cardiomyocyte nuclei while DNA laddering was evaluated by subjecting the DNA obtained from the cardiomyocytes to 1.8% agarose gel electrophoresis followed by photographing under UV illumination. The results of our study revealed that apoptotic cells appear only after 60 min of reperfusion as demonstrated by the intense fluorescence of the immunostained genomic DNA when observed under fluorescence microscopy. None of the ischemic hearts showed any evidence of apoptosis. These results were corroborated with the findings of DNA fragmentation showing increased ladders of DNA bands in the same reperfused hearts representing integer multiples of the internucleosomal DNA length (about 180 bp). Since our previous studies showed a role of glutathione peroxidase (GSHPx) in apoptotic cell death, we performed identical experiments using isolated hearts from GSHPx-l knockout mice and transgenic mice overexpressing GSHPx-l. GSHPx-l knockout mice showed evidence of apoptotic cell death even after 30 min of reperfusion. Significant number of apoptotic cells were found in the cardiomyocytes as compared to non-transgenic control animals. To the contrary, very few apoptotic cells were found in the hearts of the transgenic mice overexpressing GSHPx-l. Hearts of GSHPx-l knockout mice were more susceptible to ischemia/reperfusion injury while transgenic mice overexpressing GSHPx- 1 were less susceptible to ischemia reperfusion injury compared to non-transgenic control animals. The results of this study clearly demonstrate a role of GSHPx in ischemia/reperfusion-induced apoptosis in mouse heart.
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  • 78
    ISSN: 1573-4919
    Keywords: MKP-1 ; Fas ligand ; Fas ; apoptosis ; prostate cancer
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Abstract Recent studies have suggested that MAP kinase phosphatase 1 (MKP-1) is overexpressed in prostate cancer. To evaluate the role of MKP-1 in regulating cell death and tumor growth in prostate cancer, MKP-1 was conditionally overexpressed in the human prostate cancer cell line DU145. Overexpression of MKP-1 in DU145 cells blocked activation of stress-activated protein kinase (SAPK/JNK). MKP-1 overexpression in DU-145 cells was also found to inhibit Fas ligand (FasL)-induced apoptosis, as well as block the activation of caspases by Fas engagement. In addition, MKP-1 blocked the activation of apoptosis by transfected MEKK-1 and ASK-1, presumably through its inhibition of the SAPK/JNK family of enzymes. MKP-1 blocked the ability of FasL to induce loss of mitochondrial transmembrane potential (Δγm), suggesting that MKP-1 acts upstream of mitochondrial pro-apoptotic events induced by FasL and that the SAPK/JNK pathway may form the signaling link between Fas receptor and mitochondrial dysfunction. Thus, MKP-1 overexpression in prostate cancer may play a role in promoting prostate carcinogenesis by inhibiting FasL-induced cell death.
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  • 79
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    Molecular and cellular biochemistry 199 (1999), S. 125-137 
    ISSN: 1573-4919
    Keywords: apoptosis ; ADP-ribosylation ; caspases ; PARP ; PARG
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Abstract Poly(ADP-ribosylation) is a post-translational modification playing a relevant role in DNA damage recovery, DNA replication and viral integration. Several reports also suggest a modulation of this process during cell death by apoptosis. The aim of this review is to discuss the possible involvement of poly(ADP-ribosylation) during apoptosis, by dealing with general considerations on apoptosis, and further examining the correlation between NAD consumption and cell death, the regulation of poly(ADP-ribose) metabolism in apoptotic cells, the effect of poly(ADP-ribose) polymerase inhibition on cell death occurrence and the use of enzyme cleavage as a marker of apoptosis. Finally, the future prospects of the research in this area will be addressed.
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  • 80
    ISSN: 1573-4919
    Keywords: DNA binding protein ; NAD metabolism ; cellular response to DNA damage ; γ-rays ; alkylating agents ; genomic instability ; apoptosis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Abstract A dual approach to the study of poly (ADP-ribose)polymerase (PARP) in terms of its structure and function has been developed in our laboratory. Random mutagenesis of the DNA binding domain and catalytic domain of the human PARP, has allowed us to identify residues that are crucial for its enzymatic activity. In parallel PARP knock-out mice were generated by inactivation of both alleles by gene targeting. We showed that: (i) they are exquisitely sensitive to γ-irradiation, (ii) they died rapidly from acute radiation toxicity to the small intestine, (iii) they displayed a high genomic instability to γ-irradiation and MNU injection and, (iv) bone marrow cells rapidly underwent apoptosis following MNU treatment, demonstrating that PARP is a survival factor playing an essential and positive role during DNA damage recovery and survival.
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  • 81
    ISSN: 1573-4919
    Keywords: PARP ; poly(ADP-ribosyl)ation ; apoptosis ; DNA replication
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Abstract We have focused on the roles of PARP and poly(ADP-ribosyl)ation early in apoptosis, as well as during the early stages of differentiation-linked DNA replication. In both nuclear processes, a transient burst of PAR synthesis and PARP expression occurs early, prior to internucleosomal DNA cleavage before commitment to apoptosis as well as at the round of DNA replication prior to the onset of terminal differentiation. In intact human osteosarcoma cells undergoing spontaneous apoptosis, both PARP and PAR decreased after this early peak, concomitant with the inactivation and cleavage of PARP by caspase-3 and the onset of substantial DNA and nuclear fragmentation. Whereas 3T3-L1, osteosarcoma cells, and immortalized PARP +/+ fibroblasts exhibited this early burst of PAR synthesis during Fas-mediated apoptosis, neither PARP-depleted 3T3-L1 PARP-antisense cells nor PARP -/- fibroblasts showed this response. Consequently, whereas control cells progressed into apoptosis, as indicated by induction of caspase-3-like PARP-cleavage activity, PARP-antisense cells and PARP -/- fibroblasts did not, indicating a requirement for PARP and poly(ADP-ribosyl)ation of nuclear proteins at an early reversible stage of apoptosis. In parallel experiments, a transient increase in PARP expression and activity were also noted in 3T3-L1 preadipocytes 24 h after induction of differentiation, a stage at which ~95% of the cells were in S-phase, but not in PARP-depleted antisense cells, which were consequently unable to complete the round of DNA replication required for differentiation. PARP, a component of the multiprotein DNA replication complex (MRC) that catalyzes viral DNA replication in vitro, poly(ADP-ribosyl)ates 15 of ~40 MRC proteins, including DNA pol α, DNA topo I, and PCNA. Depletion of endogenous PARP by antisense RNA expression in 3T3-L1 cells results in MRCs devoid of any DNA pol α and DNA pol δ activities. Surprisingly, there was no new expression of PCNA and DNA pol α, as well as the transcription factor E2F-1 in PARP-antisense cells during entry into S-phase, suggesting that PARP may play a role in the expression of these proteins, perhaps by interacting with a site in the promoters for these genes.
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  • 82
    ISSN: 1573-4919
    Keywords: breast cancer cells ; anti-apoptotic genes ; apoptosis ; progesterone
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Abstract Progesterone inhibits the proliferation of normal breast epithelial cells in vivo, as well as breast cancer cells in vitro. But the biologic mechanism of this inhibition remains to be determined. We explored the possibility that an antiproliferative activity of progesterone in breast cancer cell lines is due to its ability to induce apoptosis. Since p53, bcl-2 and survivin genetically control the apoptotic process, we investigated whether or not these genes could be involved in the progesterone-induced apoptosis. We found a maximal 90% inhibition of cell proliferation with T47-D breast cancer cells after exposure to 10 μM progesterone for 72 h. Control progesterone receptor negative MDA-231 cancer cells were unresponsive to 10 μM progesterone. The earliest sign of apoptosis is translocation of phosphatidylserine from the inner to the outer leaflet of the plasma membrane and can be monitored by the calcium-dependent binding of annexin V in conjunction with flow cytometry. After 24 h of exposure to 10 μM progesterone, cytofluorometric analysis of T47-D breast cancer cells indicated 43% were annexin V-positive and had undergone apoptosis and no cells showed signs of cellular necrosis (propidium iodide negative). After 72 h of exposure to 10 μM progesterone, 48% of the cells had undergone apoptosis and 40% were annexin V positive/propidium iodide positive indicating signs of necrosis. Control untreated cancer cells did not undergo apoptosis. Evidence proving apoptosis was also demonstrated by fragmentation of nuclear DNA into multiples of oligonucleosomal fragments. After 24 h of exposure of T47-D cells to either 1 or 10 μM progesterone, we observed a marked down-regulation of protooncogene bcl-2 protein and mRNA levels. mRNA levels of survivin and the metastatic variant CD44 v7-v10 were also downregulated. Progesterone increased p53 mRNA levels. These results demonstrate that progesterone at relative high physiological concentrations, but comparable to those seen in plasma during the third trimester of human pregnancy, exhibited a strong antiproliferative effect on breast cancer cells and induced apoptosis.
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  • 83
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    Molecular and cellular biochemistry 200 (1999), S. 51-57 
    ISSN: 1573-4919
    Keywords: smokeless tobacco ; apoptosis ; nitric oxide
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Abstract Smokeless tobacco usage is, a growing public health concern in the United States. Lesions of the oral cavity have been clearly linked to smokeless tobacco use. The objective of this study was to determine the biochemical effects of smokeless tobacco extract (STE) exposure upon hamster cheek pouch cell (HCPC-1) cultures. HCPC-1 cells were exposed to a 5 -fold dose-range of STE (0.5, 1.0 and 2.5%) over a time-course of 24-96 h. Following each exposure we measured various biochemical parameters of cell proliferation and cell death. Cell viability, cell cycle progression and S-phase DNA synthesis were measured as markers of cell proliferation. We measured lactate dehydrogenase leakage as a marker of cell membrane damage and cell death due to necrosis. No significant alterations were observed in cell cycle progression and cell proliferation as a result of exposure to STE. LDH measured colorimetrically indicated no significant effect with the lower doses (0.5, 1.0 and 2.5% STE). Apoptosis measured as the A0 peak and by the TUNEL procedure revealed that STE caused significant rates of apoptosis. Maximal apoptosis was noted between 48-96 h. In order to probe the mechanism further we measured the levels of nitrites as an indicator of nitric oxide (NO) in the media. NO levels were significantly elevated at the doses that caused an induction of apoptosis. The results from this study indicate that STE causes a dose-dependent induction of apoptosis and that this is mediated by nitric oxide.
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  • 84
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    Molecular and cellular biochemistry 193 (1999), S. 37-42 
    ISSN: 1573-4919
    Keywords: Rho ; GTPase ; toxins ; Clostridium ; signal transduction ; apoptosis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Abstract The Rho family small GTPases are members of the Ras superfamily of small GTPases. Rho proteins were first determined to act as key regulators of many types of actin cytoskeletal-dependent cellular functions. Recent work by several investigators indicates that Rho GTPases are also critical modulators of several important intracellular and nuclear signal transduction pathways. Certain clostridial toxins and exoenzymes covalently modify, and thereby inactivate, specific types of Rho family GTPases. As such, these microbial enzymes have proven invaluable in helping to identify structural and functional attributes of Rho GTPases.
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  • 85
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    Molecular and cellular biochemistry 193 (1999), S. 103-108 
    ISSN: 1573-4919
    Keywords: Poly(ADP-ribose) polymerase ; Drosophila melanogaster ; alternative splicing ; apoptosis ; DNA repair ; development
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Abstract Poly(ADP-ribose) polymerase (PARP) is conserved in eukaryotes. To analyze the function of PARP, we isolated and characterized the gene for PARP in Drosophila melanogaster. The PARP gene consisted of six translatable exons and spanned more than 50 kb. The DNA binding domain is encoded by exons 1-4. Although the consensus cleavage site of CED-3 like protease during apoptosis is conserved from human to Xenopus laevis PARPs, it is neither conserved in the corresponding region of Drosophila nor Sarcophaga peregrina. There are two cDNAs species in Drosophila. One cDNA could encode the full length PARP protein (PARP I), while the other is a truncated cDNA which could encode a partial-length PARP protein (PARP II), which lacks the automodification domain and is possibly produced by alternative splicing. The expression of these two forms of PARP in E. coli demonstrated that while PARP II has the catalytic NAD-binding domain and DNA-binding domain it is enzymatically inactive. On the other hand PARP I is active. A deletion mutant of PARP gene could grow to the end of embryogenesis but did not grow to the adult fly. These results suggest that the PARP gene plays an important function during the development of Drosophila.
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  • 86
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    Molecular and cellular biochemistry 193 (1999), S. 119-125 
    ISSN: 1573-4919
    Keywords: benzamides ; nicotinamides ; apoptosis ; inflammation ; NF-kB ; DNA repair
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Abstract Our laboratory has concentrated on the possible regulation the benzamides and nicotinamides may have on the processes of DNA repair and apoptosis. Recent reports [14-16] have suggested that both apoptosis and inflammation are regulated by the transcription factor NF-kB. We have initiated studies regarding the hypothesis that the benzamides and nicotinamides could inhibit the production of tumor necrosis factor alpha (TNFalpha) and the inflammatory response as well as induce apoptosis via inhibition of NF-kB. Our data have shown that nicotinamide and two N-substituted benzamides, metoclopramide (MCA) and 3-chloroprocainamide (3-CPA), gave dose dependent inhibition of lipopolysacharide induced TNFalpha in the mouse within the dose range of 10-500 mg/kg. Moreover, lung edema was prevented in the rat by 3 ï 50 mg/kg doses of 3-CPA or MCA, and 100-200 μM doses of MCA could also inhibit NF-kB in Hela cells. Taken together these data strongly support the notion that benzamides and nicotinamides have potent anti-inflammatory and antitumor properties, because their primary mechanism of action is regulated by inhibition at the gene transcription level of NF-kB, which in turn inhibits TNFalpha and induces apoptosis.
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  • 87
    ISSN: 1573-4919
    Keywords: antisense oligonucleotide ; apoptosis ; cAMP-dependent protein kinase ; cancer cells ; growth inhibition
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Abstract The enhanced expression of the RIα subunit of cyclic AMP-dependent protein kinase type 1 (PKA-I) has been correlated with cancer cell growth. We have investigated the effects of sequence-specific inhibition of RIα gene expression on the growth of MCF-7 human breast cancer cells. We report that RIα antisense treatment results in a reduction in RIα expression at both mRNA and protein levels and inhibition of cell growth. The growth inhibition was accompanied by changes in cell morphology, cleavage of poly(ADP-ribose) polymerase (PARP) and appearance of apoptotic nuclei. In addition, bcl-2 protein level was reduced and p53 expression increased in growth arrested cells. Interestingly, RIα antisense inhibited cell viability and induced apoptosis in the absence of p53, suggesting that these actions of RIα antisense are exerted independent of p53. In contrast, two- and four-base mismatched control oligonucleotides had no effect on either cell growth or morphology. These results demonstrate that the RIα antisense, which efficiently depletes the growth stimulatory molecule RIα, induces cell differentiation and apoptosis, providing a new approach to combat breast cancer cell growth.
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  • 88
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    Molecular and cellular biochemistry 197 (1999), S. 97-108 
    ISSN: 1573-4919
    Keywords: neutrophil ; PKC ; TNF-α ; apoptosis ; DNA fragmentation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Abstract In the present study we investigated the TNF-α induced signal transduction mechanism in human neutrophil. Exogenously added TNF-α affects both PKC activity and its translocation from cytosol to the membrane. Endogenous protein phosphorylation pattern is inhibited in TNF-α induced neutrophil in Ca-dependent and Ca-independent manner, including a major 47 and 66 kDa cytosolic proteins, which may be implicated in superoxide anion generation. However TNF-α dose dependently enhances the expression of ζ-PKC isotype but not the β-PKC. Morphology and cell cytotoxicity are studied in TNF-α treated neutrophil to understand the TNF-α induced cell death or apoptosis and these experiment is further confirmed by DNA fragmentation analysis. These results clearly demonstrate that TNF-α induces cellular death of human neutrophil at least in part by enhanced expression of Ca-independent ζ-PKC. These observations provide an insight towards understanding the function of ζ-PKC in apoptotic pathway.
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  • 89
    ISSN: 1573-4919
    Keywords: rotenone ; apoptosis ; oncogenes ; liver cancer
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Abstract Rotenone decreases the incidence of hepatocellular carcinoma and lowers rates of hepatocellular proliferation. In an effort to delineate mechanisms involved, the in vivo effect of rotenone on liver mitochondrial metabolism, apoptotic machinery as well as elements of the hepatic signal transduction pathways were investigated. Mitochondria from livers of male B6C3F1 mice fed a standard diet containing 600 ppm rotenone for 7 days were uncoupled or inhibited when succinate or glutamate plus malate were used as the substrate, respectively. These livers also showed a significant increase in apoptosis compared with control livers. Furthermore, rotenone increased the expression of c-myc mRNA to 5-fold of control values within 3 days, an effect which was still observed (3-fold) after 7 days. Levels of p53 mRNA were also increased 3-fold after 1 day, but declined to control levels by 7 days. Rotenone also caused a transient, yet marked increase in liver particulate glyceraldehyde phosphate dehydrogenase (GAPDH) protein expression, while it did not alter the expression of the cytosolic form of the enzyme. Conversely, mRNA of the proto-oncogene H-ras showed a decline of 35% after 3 days of rotenone treatment, and remained diminished for the duration of the experiment. These data suggest that rotenone may act as an anticancer agent by diminishing mitochondrial bioenergetics which prevents basal hepatocyte proliferation and lowers the threshold for liver cells with DNA damage to undergo apoptosis.
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  • 90
    ISSN: 1573-4943
    Keywords: Two-dimensional electrophoresis ; MALDI-MS ; apoptosis ; RNA polymerase B transcription factor 3
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Apoptosis or programmed cell death is essential in the process of controlling lymphocyte growth and selection. We identified RNA polymerase B transcription factor 3 (BTF3), which is associated with anti-IgM antibody-mediated apoptosis, using a subclone of the human Burkitt lymphoma cell line BL60. To identify the transcription factor BTF3, which is expressed only in minor amounts, we used preparative high-resolution two-dimensional gel electrophoresis (2DE) employing carrier ampholytes for isoelectric focusing. Comparison of the 2DE protein patterns from apoptotic and nonapoptotic cells showed BTF3 as a predominantly altered protein spot. The characterization of the differentially expressed transcription factor and 13 marker proteins described in this study were performed by internal Edman microsequencing and/or by peptide mass fingerprinting using matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS). The proteome analysis was significantly improved by performing the newly developed preparative high-resolution two-dimensional gels employing high protein concentrations.
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  • 91
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    Medical microbiology and immunology 187 (1999), S. 221-226 
    ISSN: 1432-1831
    Keywords: Key wordsToxoplasma gondii ; Apoptosis ; Actinomycin D ; HL-60 ; Intracellular survival
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Intracellular microorganisms have to rely on the integrity of their host cells to persist. We, therefore, investigated the effect of infections with different Toxoplasma gondii strains on apoptosis of human-derived HL-60 cells at the single cell level. Infection with either mouse-avirulent (NTE strain) or virulent parasites (RH strain) did not induce apoptosis of HL-60 cells as compared to uninfected controls. In contrast, treatment with actinomycin D (act D) led to apoptosis in 15–25% of the cells. However, concomitant infection with T. gondii clearly abrogated act D-induced apoptosis. This was especially apparent in those host cells that were actually infected; in these parasite-positive cells the rate of apoptosis decreased by 82.8±4.3% (mean±SEM, P=0.017, Student's t-test) and 91.7±3.4% (P=0.024) after infection with either the NTE or the RH strain, respectively. Inhibition of host cell apoptosis was similarly observed in cells which had been invaded by UV-irradiated, non-replicating parasites (P=0.001, Student's t-test). However, incubation with heat-killed parasites or T. gondii lysates did not abrogate act D-induced apoptosis. In conclusion, inhibition of apoptosis by living, but not necessarily replicating T. gondii may facilitate parasite survival and persistence within its host cell.
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  • 92
    ISSN: 1432-2307
    Keywords: Key words Proliferation ; Apoptosis ; Ki-67 antigen ; Prognosis ; Retinoblastoma
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  The balance between proliferation and cell death is the major determinant of tumour growth. We analysed the proliferative and apoptotic indices (PI and AI, respectively) of 33 children with retinoblastoma. PI and AI were assessed by immunohistochemistry for Ki-67 antigen and TUNEL staining, respectively. The mean PI was 21.0±21.1%, and higher PI was associated with more advanced tumour stage (P〈0.0001) and poor clinical outcome (P〈0.05). Patients in whom amplified N-myc oncogene was found (n=6) determined by the multiplex polymerase chain reaction tended to have a higher PI (37.6±27.2%) than those without amplified N-myc (n=27; PI=17.3±18.1). A PI value of over 40% was clearly associated with an unfavourable prognosis. The AI, however, did not correlate with any of the other variables analysed. The findings suggest that proliferation, but not apoptosis, is of critical significance in retinoblastoma biology. PI, as determined by the Ki-67 antigen labelling index, seems to be a relevant histopathological parameter that can predict the clinical outcome of retinoblastoma.
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  • 93
    ISSN: 1432-0878
    Keywords: Key words Adenosine ; Nucleosides ; Neurotoxicity ; Embryogenesis ; Apoptosis ; Chick
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract  Previous work has shown that nucleosides produce apoptosis in sympathetic ganglion (SG) cells in vitro. The present study examined the effects of nucleosides on the development of the chick embryo in vivo with special attention to the SG and the optic tectum of the central nervous system. In the presence of an adenosine deaminase inhibitor, adenosine and 2’-deoxyadenosine (2’-dAdo) produced different toxicity patterns: both adenosine and 2’-dAdo were toxic to E3 embryos, but only 2’-dAdo was toxic at later stages (E6 1/2, E11). Dosage experiments on E6 1/2 embryos showed that adenosine was less toxic than 2’-dAdo and that 2’-dAdo in sublethal doses was teratogenic. We also examined the effects of 2’-dAdo on embryonic chicken SG and optic tectum in vivo to determine whether sublethal doses of 2’-dAdo produced cell death in these centers on E6 1/2 and 10. In the E6 1/2 SG, 2’-dAdo produced significant neuron loss (83%) and a decrease in SG volume (65%); however, at E10, there was only minor cell loss (7%) and no significant change in SG volume. In the optic tectum at E6 1/2, cell loss was confined mainly to the tectal ventricular zone, but there was little sign of cell loss in this organ at E10. Since cell production is vigorous in the SG and optic tectum at E6 1/2 but relatively low at E10, 2’-dAdo appears to work by stopping cell proliferation. The ineffectiveness of 2’-dAdo at E10 may result from the lethality of 2’-dAdo to the embryo at low concentrations (30 µM) in vivo, well below the apoptosis-inducing concentrations employed in vitro (100–300 µM). These data extend previous findings showing that purine and pyrimidine metabolism plays an important role in development.
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  • 94
    Electronic Resource
    Electronic Resource
    Springer
    Investigational new drugs 17 (1999), S. 227-240 
    ISSN: 1573-0646
    Keywords: apoptosis ; protein kinase C ; sphingoid bases ; safingol ; diglyceride ; bryostatin 1 ; staurosporine ; 7-hydroxy staurosporine (UCN-01) ; 4′-N-benzoyl staurosporine (CGP-41251) ; calphostin C (UCN-1028c)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Abstract Neoplastic cell survival is governed by a balance between pro-apoptotic and anti-apoptotic signals. Noteworthy among several anti-apoptotic signaling elements is the protein kinase C (PKC) isoenzyme family, which mediates a central cytoprotective effect in the regulation of cell survival. Activation of PKC, and subsequent recruitment of numerous downstream elements such as the mitogen-activated protein kinase (MAPK) cascade, opposes initiation of the apoptotic cell death program by diverse cytotoxic stimuli. The understanding that the lethal actions of numerous antineoplastic agents are, in many instances, antagonized by cytoprotective signaling systems has been an important stimulus for the development of novel antineoplastic strategies. In this regard, inhibition of PKC, which has been shown to initiate apoptosis in a variety of malignant cell types, has recently been the focus of intense interest. Furthermore, there is accumulating evidence that selective targeting of PKC may prove useful in improving the therapeutic efficacy of established antineoplastic agents. Such chemosensitizing strategies can involve either (a) direct inhibition of PKC (e.g., following acute treatment with relatively specific inhibitors such as the synthetic sphingoid base analog safingol, or the novel staurosporine derivatives UCN-01 and CGP-41251) or (b) down-regulation (e.g., following chronic treatment with the non-tumor-promoting PKC activator bryostatin 1). In preclinical model systems, suppression of the cytoprotective function(s) of PKC potentiates the activity of cytotoxic agents (e.g., cytarabine) as well as ionizing radiation, and efforts to translate these findings into the clinical arena in humans are currently underway. Although the PKC-driven cytoprotective signaling systems affected by these treatments have not been definitively characterized, interference with PKC activity has been associated with loss of the mitogen-activated protein kinase (MAPK) response. Accordingly, recent pre-clinical studies have demonstrated that pharmacological disruption of the primary MEK-ERK module can mimic the chemopotentiating and radiopotentiating actions of PKC inhibition and/or down-regulation.
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  • 95
    ISSN: 1573-0646
    Keywords: UCN-01 ; IL-2 receptor ; Fas ; Fas-ligand ; apoptosis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Abstract 7-hydroxystaurosporine (UCN-01) is a new anticancer agentwhich exerts an inhibitory effect on cell cycle check points andis currently under phase I clinical trials in US and Japan.Preliminary clinical data indicated that UCN-01 remained inplasma at high concentrations for long periods of time. Thisunavoidable high plasma drug exposure is likely to lead tohematological toxicities in patients. In the present study,cultured human peripheral blood lymphocytes (PBLs) were used toevaluate the possible hematological toxicities of UCN-01treatment. UCN-01 induces apoptosis, and the induction ofapoptosis-related surface markers were also examined toinvestigate the involvement of these molecules in UCN-01-inducedapoptosis in PBLs. in vitroviability of PBLs wasdecreased by high dose of UCN-01 (25 μM, 3-day exposure). Thiseffect of UCN-01 was significantly suppressed by the presence ofhuman serum, suggesting that some specific inhibitory factor(s)in human serum may antagonize the lympholytic effect of UCN-01.The percentage of annexin V-positive PI-negative cells increasedwith exposure to UCN-01 in a time- and dose-dependent manner; byup to 30.3% after exposure to 25 μM UCN-01 for 3 days.At the same time, the expression of both interleukin-2 receptor(IL-2R, CD25) and Fas (CD95), analyzed by flow cytometry, wasinduced. Con A-stimulated PBLs were more sensitive toUCN-01-induced apoptosis than non-stimulated lymphocytes andUCN-01 increased the sFas-L released into culture medium from conA-stimulated PBLs. Therefore, lymphocyte depletion mediated byactivation-induced apoptosis is likely to occur in patientstreated with UCN-01 at high doses.
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  • 96
    ISSN: 1573-0778
    Keywords: apoptosis ; Bcl-2 ; fixed-bed ; hollow fibre ; hybridoma ; perfusion ; protein-free medium
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract Apoptosis is an active, genetically determined death mechanism which can be induced by a wide range of physiological factors and by mild stress. It is the predominant form of cell death during the production of antibodies from murine hybridoma cell lines. A number of studies have now demonstrated that the suppression of this death pathway, by means of over-expression of survival genes such as bcl-2, results in improved cellular robustness and antibody productivity during batch culture. In the present study, the influence of bcl-2 expression on hybridoma productivity in two high density perfusion bioreactor systems was investigated. In the first system, a fixed-bed reactor, the DNA content in the spent medium was 25% higher in the control (TB/C3-pEF) culture than that found in the bcl-2 transfected (TB/C3-bcl2) cultures at all perfusion rates. This is indicative of a higher level of cell death in the control cell line. The average antibody concentration for the TB/C3-pEF cell line was 14.9 mg L-1 at perfusion rates of 2.6 and 5.2 d-1. However, for the TB/C3-bcl2 cell line it was 33 mg L-1 at dilution rates of 2 and 4 d-1. A substantial increase in antibody concentration was also found in the Integra Tecnomouse hollow fibre reactor. The antibody titre in the TB/C3-bcl2 cassette was nearly 100% higher than that in the TB/C3-pEF cassette during the cultivation period which lasted 6 weeks. Clearly, these results demonstrate the positive impact of bcl-2 over-expression on production of antibody in hybridoma perfusion cultures.
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  • 97
    ISSN: 1573-0778
    Keywords: antibody productivity ; apoptosis ; BAG-1 ; Bcl-2 ; cell survival ; hybridoma
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract Human bcl-2 and bag-1 DNA were introduced into mouse hybridoma 2E3- O cells and expressed. The expression of bcl-2 in BCMGneo-bcl2 transfectants was confirmed by ELISA and that of bag-1 in pZeo-bag1 was confirmed by western blotting. In batch cultures, the over-expression of bcl-2 prolonged the culture period by 2 days and co-expression of bcl-2 and bag-1 prolonged the culture period by 3 days. The delayed increase in the dead cell number in culture of the bcl-2 and bag-1 cotransfectant indicated the additional antiapoptosis effect of bcl-2 and bag-1 cotransfection in comparison with the bcl-2 only transfection. The bcl-2 transfectants (2E3O-Bcl2) produced antibody twofold per batch culture in comparison with 2E3-O cells transfected with BCMGSneo (2E3O-Mock). Enhancement of this MoAb production was due to the improved survival of the cells and was not due to stimulation of antibody production rate per cell by Bcl-2 expression. And the bcl-2 and bag-1 co-transfectant (2E3O-Bcl2-BAG1) produced antibody approximately fourfold of 2E3O-Mock per batch culture. Enhancement of this MoAb production was due to the improved survival of the cells and was partly due to stimulation of MoAb production rate per cell in the non-growing phase by the cotransfection. The method to engineer hybridoma cells genetically with bcl-2 and bag-1 for increasing viability and productivity would be widely applied for improving antibody productivity of hybridoma cultures.
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  • 98
    ISSN: 1573-0778
    Keywords: annexin V ; Apo-2 ligand ; apoptosis ; Cytostar-T® scintillating microplates ; flow cytometry ; lymphotoxin (LT)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract The translocation of phospholipids across the plasma membrane has been widely documented as one of the earliest measurable biochemical events of apoptosis. Using fluorescently labelled annexin V, which preferentially binds phosphatidylserine (PS) in the presence of Ca2+, the externalization of PS can be measured and apoptosis quantified using flow cytometry. Conventional detection methods utilizing annexin V, while faster than in situ DNA end-labelling or DNA laddering, require extensive sample preparation which may compromise samples and makes rapid, high volume screening prohibitive. This paper describes a novel assay for the measurement of apoptosis based upon binding of radiolabelled annexin V to apoptotic cells attached to the growth surface of a 96-well scintillating microplate (Cytostar-T®). We compared measurements of apoptosis made by flow cytometry to those obtained with the scintillating microplate in three model systems, treatment of: mouse connective tissue (L-M) cells with lymphotoxin (LT), human lung carcinoma (H460) cells with Apo-2 ligand and human umbilical vein endothelial (HUVE) cells with staurosporine. In this assay, we compare both direct and indirect labelling methods by utilizing either iodinated annexin V or biotinylated annexin V/[35S] streptavidin to radiolabel apoptotic cells. The signal detected is a direct consequence of the binding of annexin V to externalized PS on apoptotic cells and the proximity of the label to the base of the plate. Using this method, separation of bound and unbound radiolabel signal occurs directly within the well resulting in a sensitive assay that requires minimal manipulation and can accomodate a large number of samples.
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  • 99
    Electronic Resource
    Electronic Resource
    Springer
    Cardiovascular drugs and therapy 13 (1999), S. 289-294 
    ISSN: 1573-7241
    Keywords: heart failure ; apoptosis ; protein kinases ; caspases ; DNA damage ; cardiomyocytes ; β-blocks
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Apoptosis as defined by contemporary science describes a form of cell death that involves discrete genetic and molecular programs, de novo protein expression and unique cellular phenotype. Evidence for the existence of apoptosis in the human heart has been reported in various cardiac diseases, including ischemic and non-ischemic heart failure, myocardial infarction and arrhythmias. Among the most potent stimuli that elicit cardiomyocyte apoptosis are: oxygen radicals (including NO), cytokines, (FAS/TNFα family of cytokines) and growth factors/energy deprivation. Several complex signal transduction pathways have been implicated in execution of cardiomyocyte apoptosis, including: Fas/TNFα receptors signaling, stress or mitogen activated protein kinases (SAPK/MAPK), sphingolipids metabolites (ceramide), G-protein coupled receptor (GPCR) signaling (Gαi, Gαq) and NFkB activation. Apoptosis of cardiac myocytes may contribute to progressive pump-failure, arrhythmias and cardiac remodeling. The recognition of numerous molecular targets associated with cardiomyocyte apoptosis that are amenable for pharmacologic manipulation, may provide novel therapeutic strategies for diverse cardiac ailments, as recently suggested by pharmacologic studies in experimental animals.
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  • 100
    ISSN: 1573-7373
    Keywords: apoptosis ; cell death ; C6 glioma ; nerve growth factor
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Nerve growth factor (NGF) plays an important physiological role in differentiation and survival of various types of neurons. Glial cells and glial tumor cells synthesize multiple neurotrophic factors including NGF and secrete them into the surrounding environment; however, the mechanisms of NGF and the significance of NGF receptors have not been studied in detail. The C6 glioma cell line can synthesize NGF, respond to exogenous application of NGF and stimulate the expression of NGF receptor in an autocrine manner. In order to determine the significance of such an NGF autocrine system, the effects of exposure to exogenous NGF and deprivation of endogenous NGF were examined in a C6 glioma cell line in vitro. Exogenous NGF significantly inhibited maintenance of the cell number and thymidine incorporation. Morphological changes, including the formation of growth cones, outgrowth of processes and cellular hypertrophy, were observed, concurrently, indicating that exogenous NGF stimulated differentiation and thereby inhibited proliferation of the cells. Deprivation of endogenous NGF with anti-NGF antibody elicited a rapid decrease in cell number and thymidine incorporation, and led almost all of the cells to death within 8 days. The protein synthesis inhibitor, cycloheximide, strongly inhibited the death of NGF-deprived cells, suggesting the involvement of an active process requiring synthesis of suicide proteins. These findings imply that the NGF autocrine system plays a significant role in regulating the differentiation and survival of C6 glioma cells, similarly to neuronal cells.
    Type of Medium: Electronic Resource
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