A preliminary investigation of the effects of arsenate on irradiation-induced DNA damage in cultured human lung fibroblasts

Single-cell gel electrophoresis ( the comet assay) was used to assess singl e-strand breaks (SSBs) produced in cultured lung human fibroblasts by xenon lamp irradiation alone, various concentrations of arsenate [As(V)], alone or various combinations of the two. It was found that significantly higher levels of SSBs were observed in the irradiated cells than the nonirradiated cells and that elevating levels of arsenate enhanced the level of damage d etected in both irradiated and nonirradiated cells in a concentration-depen dent manner; that is, incubating cells with arsenate alone produced marked DNA damage without an irradiation insult being necessary. The results of th is study indicate that arsenate is acting as a cogenotoxin with irradiation in this cell line. This additive effect may also be cocarcinogenic, and as a result it is possible that less solar irradiation may be required to ind uce skin cancer in arsenic-exposed populations.