The expression of hypoxia-inducible factor-1α and HK-Ⅱ in esophageal squamous cell carcinoma and its effect in glycolysis / 中华消化杂志

ABSTRACT

Objective To investigate the changes of hypoxia-inducible factor(HIF)-1α and hexokinase-Ⅱ(HK-Ⅱ)expression in human esophageal squamous cell carcinoma and its effect in glycolysis.Methods TE13 cells and Eca109 cells were cultured under hypoxic condition(1 ％O2)for different hypoxic time(6,12,24 and 48 hours).Cells cultured under normal oxygen condition(20％O2)were set as control.The changes of HIF-1α and HK-Ⅱ expressions at protein level were detected by Western blot.HIF-1α genes were specifically silenced with RNA interference technology(RNAi),and then the changes of HIF-1α and HK-Ⅱ expression were determined by realtime PCR and Western blot.Under normal oxygen and hypoxic condition,the changes of lactic acid concentration in cell culture medium were detected by spectrophotometric method.Results Under hypoxic condition,the expression of HIF-1α and HK-Ⅱ gradually increased as hypoxic time extended(P＜0.05),reached a peak at 12h and then gradually decreased as time extended.Compared with that under normal oxygen condition,the expression of HK-Ⅱ in TE13 cells and Eca109 cells significantly increased under hypoxic condition(P＜0.05),which was more significant after 12 hours hypoxia.The result of realtime PCR indicated that under normal oxygen condition the expression of HIF-1α at RNA level in TE13/shRNA cells and Eca109/shRNA cells significantly decreased compared with TE13 cells and Eca109 cells without interference(P＜0.05).The expression of HK-Ⅱ at RNA level was consistent with the result of HIF-1α.Under normal and hypoxia condition,the expression of HK-Ⅱ at protein level in TE13/shRNA cells and Eca109/shRNA cells significantly decreased compared with TE13 cells and Eca109 cells without interference,and the difference was statistic significant(P＜0.05).The lactic acid secretion of TE13 cells and Eca109 cells under hypoxia condition(14.707 ± 3.594 and 15.062 ±3.901)was higher than that under normal oxygen condition(6.070±1.839 and 6.891±1.592,P＜0.05).The lactic acid secretion of TE13/shRNA cells and Eca109/shRNA cells significantly decreased compared with TE13 cells and Eca109 cells without interference,and the difference was statistic significant(P＜0.05).Conclusion The expressions of HIF-1α and HK-Ⅱ in human esophageal squamous cell carcinoma significantly increased under hypoxia conditions.The expression of HK-Ⅱ is closely correlated with lactic acid concentration and HIF-1α expression.HIF-1α may affect cell glycolysis through HK-Ⅱ.