Metabolites of Arsenic Induced Tetraploids and Mitotic Arrest in Cultured Cells

Abstract.

The toxic effects of arsenic compounds on cell division were studied, using Chinese hamster V79 cells. Seven arsenic compounds were tested. Inorganic arsenic compounds (arsenite and arsenate), which have been found in drinking water, inhibited cell growth at very low concentrations. Monomethylarsonic acid (MMA), dimethylarsinic acid (DMA), and trimethylarsine oxide (TMAO), which are methylated metabolites of inorganic arsenics, were less cytotoxic than the inorganic arsenics themselves. The cytotoxicity of the three methylated metabolites decreased as the number of methyl groups increased. Arsenobetaine (AsBe) and arsenocholine (AsC), which have been found in some marine products, did not show any cytotoxicity. Three methylated metabolites; MMA, DMA and TMAO induced mitotic arrest. Tetraploidy production was observed in cells exposed to DMA or TMAO. Arsenite, arsenate, AsBe and AsC did not induce mitotic arrest or tetraploids. These results suggest that MMA, DMA and TMAO exert some effect on cell division in metaphase and may thereby give some clue as to the carcinogenic mechanism of arsenic.