Effects of silencing HIF-1α gene by RNA interference on Taxol-induced apoptosis of human esophageal squamous cell line EC9706

Objective: To study the mechanism of hypoxia-induced drug-resistance in esophageal squamous cell carcinoma and observe the effect of hypoxia inducible factor 1 alpha(HIF-1α) on the Taxol-induced apoptosis of EC9706 cells.Methods:Small interference RNA(siRNA) targeting HIF1α was constructed and transfected into human EC9706 cells.Then EC9706 cells were cultured under chemical hypoxia conditions induced by CoCl2,a chemical hypoxia inducer.The expression of HIF-1α in EC9706 cells were detected by Western blot before and after RNA interference.The effect of Taxol on apoptosis of EC9706 cells were determined by TUNEL assay and Annexin Ⅴ/PI double staining.Results:The expression of HIF-1α protein was induced by CoCl2 75 μmol/L after 4 h,and was significantly inhibited by siRNA-HIF-1α.The apoptosis rate of EC9706 cells induced by hypoxia were significantly higher in siRNA-HIF-1α transfection group than those without transfection or transfected with control siRNA(P0.05).Conclusion:Over-expression of HIF-1α inhibited the apoptosis of EC9706 cells induced by Taxol under hypoxia.siRNA targeting HIF-1α increases the therapeutic efficacy of esophageal squamous cell carcinoma.