Antitumor effects of a selenium heteropoly complex in K562 cells.

The aim of this study was to investigate the anti-tumor effects and mechanism of the selenium heteropoly compound (C(2)H(10)N(2))(5)(NH(4))(4)H(2)[Se(2)W(10)V(8)O(62)].9H(2)O (SeWV) in K562 cells. The results showed that 0.32-10.15 x 10(-3) mmol/l SeWV could significantly inhibit the proliferation of K562 cells in vitro, as determined by the MTT assay, with IC(50) values of 3.07 and 2.69 x 10(-3) mmol/l after 48 and 72 h of treatment with SeWV, respectively. Studies of the cell cycle indicated that SeWV could induce K562 cells gathered in the G(2)/M phase upon treatment for 24 and 48 h, and a significant sub-G1 peak was evident at 0.32 and 2.54 x 10(-3) mmol/l after treatment for 24 h. Morphological observations revealed typical apoptotic features. SeWV caused the accumulation of Ca(2+), Mg(2+) and ROS, and the reduction of pH and mitochondrial membrane potential (MMP) in K562 cells as evidenced by confocal laser scanning microscopy. Experiments also showed that the expression of Bcl-2 was significantly inhibited, but Bax was increased by SeWVat 5.07 x 10(-3) mmol/l. Additionally, the content of cytochrome-C was increased after treatment for 24 h. The experiment implied that SeWV had anti-tumor activity and that its mechanism was partially attributable to the induction of cell cycle distribution and apoptosis that was induced by a change in intracellular ion homeostasis.