Quinolone antibiotics inhibit eucaryotic DNA polymerase α and β, Terminal deoxynucleotidyl Transferase but not DNA ligase
Abstract
DNA polymerases α and β, Terminal deoxynucleotidyl Transferase and DNA ligases from chicken thymus were purified to homogeneity. Quinolone antibiotics (nalidixic acid, oxolinic acid and pefloxacin) known to inhibit DNA replication were tested for their effects on these enzymes. DNA ligase activity was not affected by the three drugs. DNA polymerases α and β were inhibited by competitive mechanisms. Surprisingly, Terminal deoxynucleotidyl Transferase was strongly inhibited by the three compounds and more efficiently by nalidixic acid. The significance of these results is discussed in terms of the possible involvement of the enzymes in the respective DNA replication and repair processes.
References (36)
- B. Badet et al.
FEBS Letters
(1982) - M.F. Counis et al.
Differentiation
(1981) - M. Yoneda et al.
J. Biol. Chem
(1965) - L.M.S. Chang et al.
J. Mol. Biol
(1973) - S. Söderhäll et al.
FEBS Letters
(1976) - S. Yoshida et al.
Biochim. Biophys. Acta
(1981) - G.Y. Lesher et al.
J. Mol. Chem
(1962) - W.H. Deitz et al.
Antimicrob. Agents Chemotherap
(1963) - W.A. Goss et al.
J. Bacteriol
(1965) - W.A. Goss et al.
Mol. Gen. Genet
Science
Eur. J. Biochem
Antimicrobiol. Agents and Chemotherapy
Nuc. Acids Research
Eur. J. Biochem
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Epigenetic side-effects of common pharmaceuticals: A potential new field in medicine and pharmacology
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Genotoxicity of lomefloxacin - An antibacterial drug in somatic and germ cells of Swiss albino mice in vivo
2003, Mutation Research - Genetic Toxicology and Environmental MutagenesisThe in vivo genotoxicity of lomefloxacin, a diflourinated antibacterial drug, was evaluated by employing mouse in vivo chromosomal aberration test in bone marrow cells and dominant lethal mutation assay in germ cells. Statistically significant reduction in mitotic index, increase in chromosomal aberrations (CAs)/cell and percent abnormal metaphase was observed only at the highest dose (160 mg/kg b.w.) of the drug. In the dominant lethal mutation assay, a statistically significant decrease in the number of implants/female, compared to vehicle control, was noticed only in the females mated with males treated with 32 mg/kg b.w. during the third week of mating, while statistically significant reduction in live implants/female was noticed at both the doses during the second and third weeks of mating. Nevertheless, no significant change in the number of dead implants/female was observed after lomefloxacin treatment. These results seems to indicate that lomefloxacin is a weak clastogen in the bone marrow cells and non-mutagenic in the germ cells of mouse in vivo.
Lack of effects of ciprofloxacin and the topoisomerase II inhibitors, m-AMSA and nalidixic acid, on DNA repair in cultured rat liver cells
1996, Toxicology and Applied PharmacologySeveral quinolone antibiotics, including ciprofloxacin, have been reported to elicit autoradiographic unscheduled DNA synthesis (UDS) in cultured rat hepatocytes. In the present investigation, ciprofloxacin (CF), at 250–1500 μM, produced autoradiographic UDS in cultured rat hepatocytes, whereas neither the quinolone nalidixic acid norm-AMSA, both topoisomerase II inhibitors, produced autoradiographic UDS. CF also reduced cytoplasmic [3H]thymidine levels ([3H]TdR) relative to control at 250–1500 μMand concomitantly increased nuclear grain counts accounting for most of the net increase yielding positive UDS values. To obtain definitive information on whether the positive UDS observed with CF was due to DNA repair, DNA repair synthesis was measured in parental DNA separated from newly replicated DNA using a bromodeoxyuridine incorporation density gradient method. This method was used to measure DNA repair synthesis in parental DNA of both replicating rat liver epithelial cells (ARL-18) and nonproliferating rat hepatocytes in primary culture. Primary hepatocytes exposed to CF from 250 to 1500 μMdid not express DNA repair synthesis in parental DNA isolated by density gradient centrifugation but rather exhibited a concentration-related decrease in the level of [3H]TdR associated with DNA. In rat liver epithelial (ARL-18) cells, CF from 250 to 500 μMlikewise did not elicit DNA repair synthesis and also caused a concentration-related decrease in the level of [3H]TdR associated with parental DNA. In contrast, in both cell types a substantial level of repair synthesis occurred in parental DNA as a result of exposure to 2-acetylaminofluorene, a DNA-reactive carcinogen, and in hepatocytes a similar finding was made for the drug hydralazine. Also, after induction of DNA repair in hepatocytes by ultraviolet light, the DNA polymerase α inhibitor aphidicolin almost completely abolished repair synthesis, whereas CF had a negligible effect on the inhibition of repair relative to control. These results indicate that CF did not elicit authentic DNA repair and also did not inhibit DNA repair synthesis. The fact that CF elicited autoradiographic UDS and that the topoisomerase II inhibitorsm-AMSA and nalidixic acid did not indicates that effects on topoisomerase II are not the basis for the positive UDS result with CF as has been hypothesized in the past.
Sister-chromatid exchanges (SCE) induction by inhibitors of DNA topoisomerases in cultured human lymphocytes
1996, Mutation Research - Genetic ToxicologyThe induction of sister-chromatid exchanges (SCE) in cultured human lymphocytes by four inhibitors of DNA topoisomerases: m-amsacrine, camptothecin, etoposide and nalidixic acid has been evaluated. Although the four compounds apparently increase the frequency of SCE, the effect of nalidixic acid is weak because only a statistically significant positive response was found in one donor at the highest concentration (500 μM). The other compounds tested act as SCE inducers in both donors, camptothecin being the most effective. In addition, the influence of these four topoisomerase inhibitors on the SCE frequency induced by MMC was also analysed. The results reveal that less than additive SCE effect was induced by the combined treatments which could suggest that the process leading to SCE induction by MMC and the four inhibitors of DNA topoisomerases are not totally independent.
In vitro induction of micronuclei and chromosome aberrations by quinolones: Possible mechanisms
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Quinolone-induced differential modification of IL-1α and IL-1β production by LPS-stimulated human monocytes
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