Cytotoxic effect of three arsenic compounds in HeLa human tumor and bacterial cells

Numerous epidemiological studies suggest that arsenic (As) compounds are ca rcinogens, however, recent data have renewed the interest in their anticarc inogenic properties. The cytotoxic effects of three arsenic compounds were assessed: sodium arsenite, sodium arsenate and sodium cacodylate, represent ing the trivalent and pentavalent species of arsenic, along with a dimethyl ated pentavalent arsenic specie. HeLa cells and Salmonella typhimurium (str ains TA98 and TA100) were exposed to As compounds and the cytotoxic effects were evaluated. Alterations on RNA and DNA synthesis in HeLa cells were al so examined. All arsenic compounds produced a dose-dependent inhibition on colony formation and DNA synthesis in HeLa cells, yet any of them significa ntly influenced RNA synthesis in these cells. No evidence of arsenic-induce d mutagenicity or antimutagenicity was observed using the Ames assay. In ba cterial cells, only sodium arsenite caused a dose-dependent inhibition of c olony formation. Collectively, these results indicate that in both, HeLa and S. typhimurium cell systems, only trivalent sodium arsenite can act as an effective inhibi tor of cell growth. The possible mechanism(s) of the cytotoxic effect of ar senite in these two different cell systems might be due to its reactivity w ith intracellular sulfhydryl groups. (C) 2001 Elsevier Science B.V. All rig hts reserved.