Chao CC. Enhanced excision repair of DNA damage due to cis-diamminedichloroplatinum(II) in resistant cervix carcinoma HeLa cells.
Eur J Pharmacol 1994;
268:347-55. [PMID:
7805758 DOI:
10.1016/0922-4106(94)90059-0]
[Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
We have previously reported a cisplatin-resistant HeLa cell line which exhibits overproduction of nuclear proteins preferential for cisplatin-modified DNA (Chao et al., Cancer Res. 51:601-605, 1991; Biochem. J. 277: 875-878, 1991). In this study, excision repair of cisplatin-DNA adducts in a resistant and a revertant cell lines was investigated using in situ detection of cisplatin-DNA adducts by an immunoassay and the measurement of repair-associated DNA strand breaks by a sensitive alkaline elution method. The resistant cells exhibited a 2-fold decrease in the accumulation of cisplatin-DNA adducts; whereas, the revertant cells showed a similar level of cisplatin-DNA adducts as the parental cells in the parallel experiment. Immediately following cisplatin treatment, the resistant and the revertant cells accumulated respectively approximately 50% and 90% cisplatin-DNA adducts of the parental cells. However, the kinetic patterns of repair rate following peak accumulation of cisplatin-DNA adducts (which took approximately 4 h) was the same in the three cell lines. This finding was supported by the measurement of repair-associated DNA strand breaks using alkaline elution which showed 1.6- and 1.5-fold increase in the resistant and the revertant cells respectively. In addition, following transfection with plasmid DNA carrying cisplatin damage, the resistant and the revertant cells displayed a 2.4- and 1.4-fold enhancement in host cell reactivation, respectively. Furthermore, the acquired resistance in HeLa cells was partially reversed by nontoxic aphidicolin, a DNA polymerase-alpha and DNA repair inhibitor. The results strongly suggest the improved excision repair of cisplatin-DNA adducts as a mechanism of phenotypic resistance of cells to cisplatin.
Collapse