Effect of blocking PI3K/AKT pathway by wortmannin on hypoxia-inducible factor 1α and glycolysis in esophageal carcinoma / 中华消化杂志

ABSTRACT

Objective To investigate the inhibitory effect of blocking PI3K/AKT pathway by wortmannin on hypoxia-inducible factor 1α (HIF-1α) and the effect on the expression of glycolysis associated genes in human esophageal carcinoma cell lines TE1 and TE13,and to analyze the relation between PI3K/AKT-HIF-1α pathway and glycolysis in esophageal carcinoma cells. Methods Esophageal carcinoma cell lines TE1 and TE13 pretreated with wortmannin (2 μmol/L) were incubated under normoxic and hypoxic conditions.And each cell line was divided into four groups.The expression of HIF-1α and glycolysis associated genes GLUT-1,LDHA and HK-Ⅱ at protein level were measured by.Western blot.The expression of HIF-1α,GLUT-1,LDHA and HK-Ⅱ at mRNA level was determined by real-time PCR. The activities of LDH and HK-Ⅱ and lactic acid (LA)concentration in the culture supernatant were tested with spectrophotometer method.Results Under normoxic condition,HIF-1α was expressed in TE1 cells and the expression of HIF-1α was inhibited by wortmannin (2 μmol/L),the most significant inhibitory effect was at 12 hours,therefore 12 hours was selected for the subsequent hypoxia experiment.Compared with untreated cells,the expression of HIF-1α、HK-Ⅱ 、GLUT-1、LDH-A at protein level significantly decreased in TE1 and TE13 cells after pretreated with wortmannin (P ＜ 0.05),and the expression of HIF-1α、HK-Ⅱ at mRNA level significantly decreased (P＜ 0.05).Under normoxic and hypoxic conditions,the HK-Ⅱ and LDH activities in TE1 and Te13 esophageal carcinoma cells significantly decreased after treated with wortmannin compared with untreated cells (P＜0.05).Under hypoxia condition,the enzyme activity increased in untreated cells (P＜ 0.05). Under normoxic and hyp0xic conditions,the lactic acid concentration in the culture supernatant obviously decreased in cells treated with wortmannin compared with untreated cells (P＜ 0.05). Under hypoxia condition,lactic acid concentration increased in wortmannin treated cells (P ＜ 0.05). Conclusions Under normoxic and hypoxic conditions,wortmannin decrease lactic acid concentration through inhibiting the expression of HIF-1α and glycolysis associated genes, which indicate PI3K/AKT-HIF-1α pathway was closely related to glycolysis in esophageal carcinoma cells.