[Use of Escherichia coli recF mutant strains for analyzing the genotoxicity of complex platinum compounds]

The bioluminescence method of assessing SOS response in Escherichia coli cells was applied to test the genotoxicity of five complex platinum compounds: cis-diamminedichloroplatinum, cycloplatam, trans-diamminedichloroplatinum, and two trans-binuclear complexes. Strains AB1157 (pPLS-1) and JC9239 (pPLS-1), a variant of AB1157 carrying the recF143 mutation, were used in the test procedure. SOS response in JC9239 cells was shown to be induced by significantly lower concentrations of cis-DDP and cycloplatam than in AB1157 cells. A drastic increase in cis-DDP toxicity for the JC9239 strain was shown. However, the presence of the recF mutation in JC9239 cells retarded the SOS response induced by trans-platinum compounds. The results obtained indicated that the E. coli recF system plays an essential role in repair and utilization of cis-DDP-DNA adducts.