Abstract: Objective To explore the effect of sodium selenite on AMPK/mTOR signaling pathway and its regulation of apoptosis in leukemia cells NB4. Methods NB4 cells were treated with sodium selenite with different concentrations or in a time dependent manner, then the phosphorylation level of AMPK, mTOR and P70S6K were detected by Western blot. To investigate the effect of AMPK on mTOR and apoptosis in NB4, cells were treated by AMPK activator AICAR and siRNA which targeted AMPK. The phosphorylation level of AMPK, mTOR and P70S6K were detected by Western blot, and apoptotic rates were analyzed by Annexin V/PI double staining. The interaction between AMPK and mTOR was evaluated by co-immunoprecipitation assay.Results Sodium selenite can activate AMPK, inhibit mTOR and promote apoptosis in NB4 cells. When NB4 cells were treated with AICAR alone, an activator of AMPK, apoptosis was induced which was similar to that of selenite. When AMPK was knocked down with specific siRNA, phosphorylation of mTOR and P70S6K increased and selenite-induced apoptosis was attenuated in NB4 cells. Results of co-immunoprecipitation show there is a direct interaction between AMPK and mTOR. Conclusion Sodium selenite can activate AMPK， inhibit mTOR and P70S6K， thus promote apoptosis in NB4 cells.

Key words: sodium selenite, leukemia, AMPK, mTOR