XRCC1 Protects against Particulate Chromate–Induced Chromosome Damage and Cytotoxicity in Chinese Hamster Ovary Cells

Water-insoluble hexavalent chromium compounds are well-established human lung carcinogens. Lead chromate, a model insoluble Cr(VI) compound, induces DNA damage, chromosome aberrations, and dose-dependent cell death in human and Chinese hamster ovary (CHO) cells. The relationship between lead chromate–induced DNA damage and chromosome aberrations is unknown. Our study focus was on examining the role of XRCC1 in lead chromate–induced cytotoxicity and structural chromo-somal aberrations in CHO cells. Three different cell lines were used: AA8 (parental), EM9 (XRCC1 mutant), and H9T3 (EM9 complemented with human XRCC1 gene). Cytotoxicity was significantly higher in EM9 cells when compared to AA8 and H9T3 cells, indicating that XRCC1 is important for protecting cells from lead chromate particles–induced cell death. The frequency of damaged metaphase cells was not affected b