Effect of trivalent arsenicals on cell proliferation in mouse and human microvascular endothelial cells

Chronic exposure to high levels of inorganic arsenic(iAs) has been associated with cancerous and noncancerous health effects, including cardiovascular effects. However, the mechanism for a presumed toxic effect of arsenic on vascular tissue is not clear. Our working hypothesis is that inorganic trivalent arsenic and its methylated metabolites react with cysteine-containing cellular proteins and alter their function leading to adverse events such as cytotoxicity or proliferation. In this study, human microvascular endothelial cells(HMEC1) and mouse microvascular endothelial cells(MFP-MVEC) were exposed to arsenite(iAs"), monomethylarsonous acid(MMA"), or dimethylarsinous acid(DMA") for 72 h to evaluate cytotoxicity, and for 24, 48 or 72 h to evaluate cell proliferation. Both cell lines showed similar LC50 values, from 0.1 to 2.4 M, for all three trivalent arsenicals. The endothelial cells treated withl nM to 1 OA concentrations of the three trivalent arsenicals did not show increased cell proliferation at 24, 48 or 72 h or increased rate of proliferation at 72 h of exposure. Overall, cytotoxicity of trivalent arsenicals to microvascular endothelial cells is similar to their cytotoxicity to epithelial cells, and that these compounds are not mitogenic. (C) 2015 The Authors. Published by Elsevier Ireland Ltd.