title: Induction of 6-thioguanine-resistant mutants and single-strand scission of DNA by cadmium chloride in cultured Chinese hamster cells.
abstract: Inducibility of 6-thioguanine-resistant (6TGr) mutants and single-strand scission of DNA by cadmium chloride (CdCl2) was investigated in cultured Chinese hamster V79 cells. Frequency of 6TGr mutants increased concentration dependently by 24-h treatment with CdCl2 up to 3 X 10(-6) M but decreased beyond 3 X 10(-6) M. Mutagenic potency of cadmium in the absence of S9 was about half that of benzo[a]pyrene in the presence of S9 at equitoxic concentrations. Treatment of the cultured cells with cadmium after benzo[a]pyrene treatment was not synergistic but additive to the mutagenicity of benzo[a]pyrene. Single-strand scission of DNA by alkaline elution techniques was observed in the cells treated with CdCl2 for 2 h in a concentration-dependent manner. The single-strand scission by cadmium was detected only in combination with proteinase K digestion of the cell lysates, indicating formation of DNA--protein cross-linking by the metal. These biological and biochemical findings indicate that cadmium is mutagenic in mammalian cells, and its mutagenic effect seems to be accompanied by single-strand scission of DNA.
mesh_terms: D000818:Animals; D001564:Benzo(a)pyrene; D001580:Benzopyrenes / Q000494:pharmacology; D002104:Cadmium / Q000494:pharmacology*; D019256:Cadmium Chloride; D002455:Cell Division / Q000187:drug effects; D002460:Cell Line; D006224:Cricetinae; D003412:Cricetulus; D004247:DNA / Q000378:metabolism*; D004351:Drug Resistance; D008168:Lung / Q000187:drug effects; D009154:Mutation; D013866:Thioguanine / Q000494:pharmacology*
chemical_list: D001580:Benzopyrenes; D002104:Cadmium; D001564:Benzo(a)pyrene; D004247:DNA; D013866:Thioguanine; D019256:Cadmium Chloride