EGFR对胃癌细胞SGC7901化疗敏感性及细胞中STAT3磷酸化水平的影响

摘要

Objective:To investigate the effect of EGFR on the chemosensitivity of gastric cancer cell line SGC7901 and the level of STAT3 phosphorylation in cells.Methods:Gastric cancer tissues and corresponding adjacent tissues were collected,cultured gastric cancer cells MKM28,SGC7901,BGC823 and gastric epithelial cells GES-1 in vitro.The expression of EGFR in MKM28,SGC7901,BGC823 and gastric epithelial cell line GES-1 in gastric cancer tissues,adjacent tissues and gastric cancer cells were detected by Western blot.Cells were transfected with small interfering RNA (siRNA control group) and EGFR small interfering RNA (EGFR siRNA group).Meanwhile,set up the control group (only adding transfection reagent),chemotherapy group (cell culture medium added 8 μmol/L of 5-fluorouacil),combined group (transfected EGFR siRNA cells,cell culture medium with 8 μmol/L of the 5-fluorouacil).After culturing 48 h,the expression of Cleaved Caspase-3,STAT3,p-STAT3 and EGFR in the cells were detected by Western blot.Cell proliferation was detected by MTT,cell apoptosis was detected by flow cytometry.Results:The expression level of EGFR in gastric cancer tissues were significantly higher than that in adjacent tissues,the expression level in gastric cancer cells were significantly higher than that in gastric epithelial cells.The level of EGFR in EGFR siRNA cells was significantly decreased.The cell survival rate and p-STAT3 expression level in EGFR siRNA group,chemotherapy group and combination group were significantly lower than those in control group,the apoptosis rate and the level of Cleaved Caspase-3 in the cells were significantly higher than those in the control group.The survival rate and the expression of p-STAT3 in the combined group were significantly lower than those in the chemotherapy group,the apoptosis rate and the level of Cleaved Caspase-3 in the cells were significantly higher than those in the chemotherapy group.Conclusion:Overexpression of EGFR in gastric carcinoma.After inhibition of EGFR expression,gastric cancer cell proliferation was inhibited,apoptosis increased,increased sensitivity to chemotherapy,the mechanism of action may be related to the level of STAT3 phosphorylation.%目的:探讨表皮生长因子受体(epidermal growth factor receptor,EGFR)对胃癌细胞SGC7901化疗敏感性及细胞中信号转导和转录因子3(STAT3)磷酸化水平的影响.方法:收集胃癌组织及对应的癌旁组织,体外培养胃癌细胞MKM28、SGC7901、BGC823和胃黏膜上皮细胞GES-1,Western blot检测胃癌组织、癌旁组织及胃癌细胞MKM28、SGC7901、BGC823和胃黏膜上皮细胞GES-1中EGFR的表达水平.细胞转染小干扰RNA对照序列(siRNA control组)和EGFR小干扰RNA(EGFR siRNA组),同时设置对照组(只加入转染试剂)、化疗组(细胞培养液中加入8 μmol/L 5-氟尿嘧啶)、联合组(转染EGFR siRNA后的细胞,细胞培养液中加入8 μmol/L 5-氟尿嘧啶),培养48 h后,Western blot检测细胞中活化的含半胱氨酸的天冬氨酸蛋白水解酶3(Cleaved Caspase-3)、信号转导和转录因子3(STAT3)、磷酸化STAT3(p-STAT3)、EGFR表达水平,噻唑蓝(MTT)检测细胞增殖情况,流式细胞术检测细胞凋亡情况.结果:EGFR在胃癌组织中表达水平明显高于癌旁组织,在胃癌细胞中的表达水平明显高于胃黏膜上皮细胞.EGFR siRNA组细胞中EGFR水平明显降低.EGFR siRNA组、化疗组、联合组细胞存活率及p-STAT3表达水平明显低于对照组，而凋亡率及细胞中Cleaved Caspase-3水平明显高于对照组。联合组细胞存活率及p-STAT3表达水平明显低于化疗组，而凋亡率及细胞中Cleaved Caspase-3水平明显高于化疗组。结论:EGFR在胃癌中过表达.抑制EGFR表达后,胃癌细胞增殖受到抑制,凋亡增多,化疗敏感性增加,作用机制可能与STAT3磷酸化水平有关.