Lowering extracellular calcium content protects cells from arsenite-induced killing and micronuclei formation

The present study demonstrated that calcium ions were accumulated in nuclei of Chinese hamster ovary (CHO)-K1 cells after arsenite treatment. This process was enhanced by verapamil (a calcium channel blocker). Verapamil also significantly increased the cytotoxic effects of arsenite. In contrast, ethylene glycol-bis[beta-aminoethylether] N,N, N1,N1,-tetraacetic acid (EGTA, a calcium-specific chelator), or calcium-free conditions significantly reduced the cytotoxicity or arsenite. Similarly, the strategy of lowering extracellular calcium concentration by modifying the medium or lowering intracellular calcium concentration by administration of the intracellular calcium chelator quin 2, protected cells from arsenite-induced micronuclei formation. These data indicate that the disturbances in intracellular calcium homeostasis maybe involved in arsenite-induced cytotoxicity and micronuclei formation.