Objective To observe the radiotherapy sensitivity of esophageal carcinoma cells with down-regulated ex-pression of hypoxia-inducible factor-1α(HIF-1α)and to explore its mechanism.Methods Human esophageal cancer cell lines EC9706,TE-2,TE-7 and TE-8 were cultured and were given 2,4 and 6 Gy X-ray radiotherapy,respectively.The cell proliferation inhibition rate was observed by CCK-8 method,and the cell line with the lowest cell proliferation inhi-bition rate was selected as the cell line with the best radiotherapy tolerance for follow-up study,and the radiotherapy dose with inhibition rate of cell proliferation less than 50%at 72 h after X-ray irradiation was selected as the radiotherapy dose for follow-up study.The selected cell lines were further divided into the control group,radiotherapy group,HIF-1α down-expression group,and radiotherapy+HIF-1α down-expression group,respectively;siRNA-HIF-1α was transfected into the HIF-1α down-expression group and radiotherapy+HIF-1α down-expression group by the liposome transfection.Accord-ing to the selected radiotherapy dose,the cells in the radiotherapy group and the radiotherapy+HIF-1α down-expression group were treated with single radiotherapy,while cells in the control group and HIF-1α down-expression group were cul-tured without radiotherapy.The cell radiotherapy sensitivity of each group was observed by CCK-8 method,and vascular endothelial growth factor(VEGF),E-cadherin,and Vimentin were detected by Western blotting.Results The prolifera-tion inhibition rate of EC9706 cells was the lowest at 2,4 and 6 Gy radiotherapy dose,and the proliferation inhibition rate of EC9706 cells was less than 50%at 2 Gy radiotherapy dose.Therefore,2 Gy was selected as the follow-up radiation dose.Cell proliferation inhibition rate was as follows:control group<radiotherapy group<HIF-1α down-expression group<radiotherapy+HIF-1α down-expression group,VEGF protein expression was as follows:control group>radiothera-py group,HIF-1α down-expression group>radiotherapy+HIF-1α down-expression group,Vimentin protein expression was in the following order:control group>radiotherapy group>HIF-1α down-expression group>radiotherapy+HIF-1α down-expression group,and the E-cadherin protein expression was as follows:control group<radiotherapy group,HIF-1α down-expressionn group<radiotherapy+HIF-1α down-expression group(all P<0.05).Conclusion Esophageal cancer cells with down-regulated HIF-1α expression are more sensitive to radiotherapy,and the mechanism may be related to the inhibition of tumor angiogenesis and epithelial-mesenchymal transformation.
维普
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