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  • 1
    Electronic Resource
    Electronic Resource
    Cytoplasmic and nuclear localization sites of phosphatidylinositol 3-kinase in human osteosarcoma sensitive and multidrug-resistant Saos-2 cells (1996)
    Springer
    Histochemistry and cell biology 106 (1996), S. 457-464 
    Details
    ISSN: 1432-119X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract  The intracellular localization of phosphatidylinositol 3-kinase (PI 3-kinase) has been analyzed by western blotting, confocal, and electron microscopy immunocytochemistry in human osteosarcoma Saos-2 cells. By western blotting, the enzyme appears to be present in both the cytoplasmic and nuclear subfractions. By confocal microscope immunocytochemistry, the cytoplasmic fluorescence is localized in the perinuclear region and on a network of filaments, while a diffused signal is present in the nucleus, except for the nucleolar areas. Ultrastructural analyses on whole cells and on in situ matrix preparations reveal that nuclear PI 3-kinase is localized in interchromatin domains, in stable association with inner nuclear matrix components, while the enzyme diffused in the cytosol is partly associated with the cytoskeletal filaments. Quantitative evaluations indicate that, in a multidrug-resistant variant obtained by continuous exposure of Saos-2 cells to doxorubicin, the amount of nuclear and cytoplasmic PI 3-kinase is significantly lower than in the sensitive parental cell line. The nuclear localization of PI 3-kinase and its variation in multidrug-resistant cells, characterized by a reduced mitotic index, are consistent with the data on the existence of a nuclear inositol lipid cycle, which could also utilize 3-phosphorylated inositides to modulate signal transduction for the control of some key functional activities.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004180050064
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    Paper (German National Licenses)
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  • 2
    Electronic Resource
    Electronic Resource
    Cytoplasmic and nuclear localization sites of phosphatidylinositol 3-kinase in human osteosarcoma sensitive and multidrug-resistant Saos-2 cells (1996)
    Springer
    Histochemistry and cell biology 106 (1996), S. 457-464 
    Details
    ISSN: 1432-119X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract The intracellular localization of phosphatidylinositol 3-kinase (PI 3-kinase) has been analyzed by western blotting, confocal, and electron microscopy immunocytochemistry in human osteosarcoma Saos-2 cells. By western blotting, the enzyme appears to be present in both the cytoplasmic and nuclear subfractions. By confocal microscope immunocytochemistry, the cytoplasmic fluorescence is localized in the perinuclear region and on a network of filaments, while a diffused signal is present in the nucleus, except for the nucleolar areas. Ultrastructural analyses on whole cells and on in situ matrix preparations reveal that nuclear PI 3-kinase is localized in interchromatin domains, in stable association with inner nuclear matrix components, while the enzyme diffused in the cytosol is partly associated with the cytoskeletal filaments. Quantitative evaluations indicate that, in a multidrug-resistant variant obtained by continuous exposure of Saos-2 cells to doxorubicin, the amount of nuclear and cytoplasmic PI 3-kinase is significantly lower than in the sensitive parental cell line. The nuclear localization of PI 3-kinase and its variation in multidrug-resistant cells, characterized by a reduced mitotic index, are consistent with the data on the existence of a nuclear inositol lipid cycle, which could also utilize 3-phosphorylated inositides to modulate signal transduction for the control of some key functional activities.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02473307
    Library Location Call Number Volume/Issue/Year Availability
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    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    Interleukin-1α induces variations of the intranuclear amount of phosphatidylinositol 4,5-bisphosphate and phospholipase C β1 in human osteosarcoma Saos-2 cells (1996)
    Springer
    Journal of molecular histology 28 (1996), S. 495-504 
    Details
    ISSN: 1573-6865
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Some key elements of signal transduction have been identified within the nucleus and demonstrated to be responsive to specific agonists in numerous cell types. In particular, mitogenic stimuli have been reported to induce, a transient increase of the nuclear phospholipase C β1 activity, causing the release of inositide-derived second messengers, whereas differentiating stimuli induced a decrease of the enzyme activity and an increase of nuclear phosphatidylinositol 4,5-bisphosphate (PIP2). Recently, we reported evidence, in human osteosarcoma Saos-2 cell lines, on the presence of specific nuclear phospholipase C isoforms and on the activation of phospholipase C β1 in the nucleus following the exposure to interleukin-1α. In this study we report immunocytochemical ultrastructural evidence on quantitative variations of PIP2 and phospholipase C β1 amounts in the nucleus of Saos-2 cells at different times of exposure to interleukin-1α. After short periods of culture in the presence of the agonist, the intranuclear amount of PIP2 is decreased, while a translocation of phospholipase C β1 occurs from the cytoplasm to the nucleus, in correspondence with the increased hydrolyzing activity of the enzyme. After longer periods of incubation with interleukin-1α, on the other hand, the intranuclear amount of PIP2 is restored to initial level, while the amount of phospholipase C β1 is increased both at the nuclear and cytoplasmic level, when its activation is no longer effective. The results, compared with those obtained in other cell types responsive to given agonists, account for a cell-specific modulation of signal transduction based on polyphosphoinositide breakdown at the nuclear level.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02331409
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    Paper (German National Licenses)
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  • 4
    Electronic Resource
    Electronic Resource
    Establishment and characterization of two new cell lines derived from human metastatic breast carcinomas (1997)
    Springer
    Breast cancer research and treatment 43 (1997), S. 141-151 
    Details
    ISSN: 1573-7217
    Keywords: chemosensitivity pattern ; cytogenetics ; hormone receptors ; human breast cancer cell line ; oncogenes ; tumor markers ; ultrastructural analysis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Two human cancer cell lines (MA 2 and MA 3) were established from pleural effusions of infiltrating ductal carcinomas of the breast.The lines were maintained in continuous monolayer culture withdoubling times of 70 (MA 2) and 78 (MA 3) hr for more than two years and possessed extensively rearranged abnormal karyotypeswith modal chromosome number of 83 (MA 2) and 81 (MA 3) and DNA index values of 1.65 and 1.77, respectively. No amplifications or rearrangements were evident in the c-myc, int-2, c-erb B2, c-Ha-ras, or hst 1 genes in MA 2 and MA 3 cell lines. The clinical histories of the patients from whom the cell lines were derived are reported and compared with the results observed inthe cell lines in vitro. The presence of CEA, CA 15-3, and MCA tumormarkers observed in the primary tumor tissues was retained by the established cell lines. While the primary tumor tissueswere ER+/PgR borderline + (MA 2) and ER−/PgR+(MA 3), the MA 2 line was ER+/PgR− and the MA 3 line remained ER−/PgR+. The MDR P-glycoprotein was not expressed either in primary tumor tissues or in the respective cell lines. High expression of cytokeratins7, 18, and 19 was evident by immunohistochemical analysis in each cell line, whereas cytokeratins 8 and 17 were poorly or not at allexpressed. The treatment history of the patients fromwhom the cell lines were derived involved CMF followed six monthslater by novantrone and cisplatin plus VP 16 (MA 2) and FEC followedfour years later by CMF (MA 3). The chemosensitivitypattern assay of the cell lines indicated that the MA 2 linewas sensitive to doxorubicin, cisplatin, and vinblastine, whereas theMA 3 line was sensitive to doxorubicin and cisplatin. The characteristics of these cell lines indicate them to be a goodexperimental model to investigate breast cancer biology and anticancerdrug response.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1005740813216
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    Paper (German National Licenses)
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