Abstract: Objective We studied the cooperativity of selenite and gossypol to induce apoptosis in SW480 colorectal cancer cells. Methods Investigate the changes of Bcl-2 protein familys in SW480.SW480 cells were divided into three groups: 6μmol/L gossypol, 10 μmol/L selenite and both of them, then we observed the apoptosis by DAPI staining and fluorescence microscopy. Finally, we detected the cell death induced by different concentration gossypol and selenite in Bax/Bak deficient MEF cell. Results The expression of Bim and Bax proteins increased while Mcl-1 and Bcl-xl decreased in SW480 cells after selenite administration. Nucleus fragmentation rates and cell death in SW480 were significantly increased after the combined treatment of selenite and gossypol（P＜0.05）. In Bax/Bak deficient cells, gossypol can still promote apoptosis. Conclusion Selenite and gossypol can promote apoptosis via different pathways, selenite increases the sensitivity of tumor cells to apoptosis through Bim and Bax, while gossypol reduced the resistance to apoptosis of tumor cell, and the combination of them produced synergistic effect inducing apoptosis in SW480 cells.

Key words: Selenite, Gossypol, Apoptosis, Combination chemotherapy