Vanadate induces apoptosis in epidermal JB6 P+ cells via hydrogen peroxide-mediated reactions

Apoptosis is a physiological mechanism for the control of DNA integrity in mammalian cells. Vanadium induces both DNA damage and apoptosis. It is sugg ested that vanadium-induced apoptosis serves to eliminate DNA-damaged cells . This study is designed to clarify a role of reactive oxygen species in th e mechanism of apoptosis induced by vanadium. We established apoptosis mode l with murine epidermal JB6 P+ cells in the response to vanadium stimulatio n. Apoptosis was detected by a cell death ELISA assay and morphological ana lysis. The result shows that apoptosis induced by vanadate is dose-dependen t, reaching its saturation level at a concentration of 100 mu M vanadate. V anadyl (IV) can also induce apoptosis albeit with lesser potency. A role of reactive oxygen species was analyzed by multiple reagents including specif ic scavengers of different reactive oxygen species. The result shows that v anadate-induced apoptosis is enhanced by NADPH, superoxide dismutase and so dium formate, but was inhibited by catalase and deferoxamine. Cells exposed to vanadium consume more molecular oxygen and at the same time, produce mo re H2O2 as measured by the change in fluorescence of scopoletin in the pres ence of horseradish peroxidase. This change in oxygen consumption and H2O2 production is enhanced by NADPH. Taken together, these results show that va nadate induces apoptosis in epidermal cells and H2O2 induced by vanadate pl ays a major role in this process.