Sodium selenite inhibits leukemia HL-60 cell proliferation and induces cell apoptosis by enhancing the phosphorylation of JNK1 and increasing the expression of p21 and p27

Selenium is an essential trace element and has shown chemopreventive or therapeutic activities on human solid cancers; however, whether it has anticancer effects on leukemia has not yet been elucidated. The present study was designed to determine the role of selenium on HL-60 human promyelocytic leukemia cells. We found that 100 nM of sodium selenite (Se) had no significant effects on cell proliferation, apoptosis and the cell cycle; however, a higher concentration of 250 nM of Se significantly inhibited cell proliferation, promoted apoptosis and induced cell cycle arrest at the S phase after 48 h of treatment (P<0.05), thus demonstrating the anticancer activities of selenium in leukemia. However, the decrease in c-Jun NH2-terminal kinase 1 (JNK1) expression by targeting JNK1 using small interfering RNA attenuated the inhibitory effects of Se on cell proliferation and the induction of apoptosis. Mechanistic studies showed that the anticancer activities of Se were associated with the enhanced phosphorylation of JNK1 and the increased expression of the cell cycle regulators, p21 and p27, as well as the downregulation of cyclin D1. Our data provide further evidence that the appropriate concentration of selenium has therapeutic potential in leukemia.