title: Comutagenic effects of 3-aminobenzamide in Chinese hamster ovary cells.
abstract: Inhibition of poly (ADP-ribose) synthesis by agents such as 3-aminobenzamide (3-AB) potentiates the cytotoxic, carcinogenic, and clastogenic effects of certain DNA-damaging agents. Experiments were carried out in Chinese hamster ovary cells to compare chromosome aberration production and cytotoxicity with the induction of somatic mutations at the hypoxanthine-guanine phosphoribosyltransferase (HGPRT) and sodium-potassium ATPase loci after treatment with 3-AB in combination with certain monofunctional alkylating agents. On its own, 1 to 10 mM concentrations of 3-AB were not mutagenic, reduced plating efficiencies only slightly, and produced a small elevation in the frequency of chromatid aberrations. In combination with ethyl methanesulfonate (EMS), 3-AB increased cytotoxicity and the frequency of alkylation-induced chromatid aberrations. 3-AB also increased the frequency of EMS and N-methyl-N'-nitro-N-nitrosoguanidine-induced 6-thioguanine-resistant cells (a marker for the HGPRT- phenotype). It had no effect on the frequency of EMS-induced ouabain-resistant cells (a marker for ATPase mutations). All the effects were dose dependent. Larger absolute increases were found with 10 mM 3-AB as compared with 1 mM 3-AB and with 2 mM EMS as compared to 1 mM EMS. The 3-AB-mediated increases in 6-thioguanine-resistant cells, which are often deletion mutations, and the lack of any increase in the frequency of ouabain-resistant cells, which can only arise through point mutation induction, along with the increases in chromosome aberration frequency, suggests that 3-AB increases the frequency of deletion mutations by increasing the frequency and duration of DNA strand breaks.
mesh_terms: D000818:Animals; D001549:Benzamides / Q000633:toxicity*; D002470:Cell Survival / Q000187:drug effects; D002478:Cells, Cultured; D002869:Chromosome Aberrations; D006224:Cricetinae; D003412:Cricetulus; D004247:DNA; D004357:Drug Synergism; D005020:Ethyl Methanesulfonate / Q000633:toxicity; D005260:Female; D008769:Methylnitronitrosoguanidine; D009153:Mutagens; D009154:Mutation; D010053:Ovary
chemical_list: D001549:Benzamides; D009153:Mutagens; D008769:Methylnitronitrosoguanidine; C025160:3-aminobenzamide; D004247:DNA; D005020:Ethyl Methanesulfonate