LACK OF CORRELATION BETWEEN REPAIR OF DNA INTERSTRAND CROSS-LINKS ANDHYPERSENSITIVITY OF HAMSTER-CELLS TOWARDS MITOMYCIN-C AND CISPLATIN

The ability to repair DNA interstrand cross-links may be an important factor contributing to mitomycin C (MMC) and cisplatin cytotoxicities, We have assessed the repair of interstrand cross-links induced by MMC in two MMC-hypersensitive hamster cell mutants and their resistant pa rental cell line. Using a gene-specific repair assay, we found no evid ence for repair of MMC cross-links in either parental or mutant cells, suggesting that persistence of DNA interstrand cross-links is not res ponsible for the differential toxicity of MMC towards hypersensitive c ells. Repair of cisplatin-induced interstrand cross-links was efficien t in resistant as well as in mutant cells. Therefore we concluded that a defect in excision repair of interstrand crosslinks was not respons ible for the cytotoxic effects of MMC and cisplatin in these hypersens itive mutants. (C) 1998 Federation of European Biochemical Societies.