Abstract:

OBJECTIVE: To study the role of AMPK in autophagy which was induced by vitamin E succinate (VES) in human gastric cancer SGC-7901 cells. METHODS: SGC-7901 cells were treated with different doses (5,10,15,20 μg/mL) of VES or with 20 μg/mL VES for 3,6,12,24 h. Western blot was used to evaluate the microtubule-associated protein 1 light chain 3 (LC3,an autophagy marker protein),Beclin-1 and the phosphorylation level of AMPK. RNAi was used to silence AMPK expression in SGC-7901 cells,then these cells were treated with 20 μg/mL VES for 24 h. Western blot was used to evaluate the protein levels of LC3,Beclin-1,phosphorylation level of AMPK,mTOR,p70S6K and 4EBP-1. Real-time PCR was used to detect the mRNA level of LC3. RESULTS: With increasing doses of VES,and prolonged time of VES treatment,the phosphorylation level of AMPK,LC3 and Beclin-1 were elevated compared with controls (P<0.05). When AMPK was silenced,in VES treatment plus AMPK silenced group,both the protein level of LC3,Beclin-1 and LC3 mRNA were decreased,compared with those among the non-silenced group (P<0.05),and the protein activity of mTOR,p70S6K and 4EBP-1 were increased (P<0.05). CONCLUSION: The activity of AMPK was up-regulated in VES-treated human gastric cancer SGC-7901 cells. AMPK was involved in VES-induced autophagy via inhibiting mTOR and its downstream molecular activity.

Key words: vitamin E succinate, AMPK, autophagy, gastric cancer cell line