Induction of differentiation and apoptosis by sodium selenite in human colonic carcinoma cells (HT29)

To explore the mechanism(s) by which selenium (Se) exerts its cancer chemopreventive activity, we studied the effect of selenite (0-100 mu M) on cell growth, viability, differentiation, detachment, DNA fragmentation and apoptosis in human colonic carcinoma cells (HT29). Selenite (greater than or equal to 5 mu M) decreased cell growth, increased cell detachment and decreased intracellular levels of reduced glutathione (GSH), whereas greater than or equal to 10 mu M selenite induced cell differentiation and apoptosis. The chemopreventive effects of selenite may be related in part to the generation of reactive oxygen species (ROS) resulting from the reaction between selenite and GSH. (C) 1997 Elsevier Science Ireland Ltd.