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.