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目的探讨表没食子儿茶素没食子酸酯(EGCG)抑制IL-6诱导胃癌血管生成的作用及机制。方法以50 ng/mL IL-6或不同浓度EGCG培养AGS胃癌细胞株,Western blot免疫印迹法检测胃癌细胞血管内皮生长因子(VEGF)的表达;Elisa法检测肿瘤细胞培养液中VEGF的蛋白水平;RT-PCR检测胃癌细胞VEGF mRNA表达;制备胃癌细胞条件培养液培养血管内皮细胞,采用MTT法检测血管内皮细胞的体外增殖;小管形成实验检测血管内皮细胞体外小管形成;基质胶(matrigel)塞实验检测体内血管形成。结果 IL-6诱导胃癌细胞VEGF蛋白表达增加2.4倍,VEGF蛋白分泌增加2.8倍,而VEGF mRNA表达增加3.1倍;EGCG呈剂量依赖性地抑制IL-6诱导的胃癌细胞VEGF蛋白的表达、分泌和VEGF mRNA表达。VEGF中和抗体及EGCG在体外可以显著抑制IL-6诱导的血管内皮细胞增殖(t=3.02,P<0.01;t=2.56,P<0.05)和小管形成(t=3.38,P<0.01;t=3.61,P<0.01)以及在体内的血管生成(t=2.66,P<0.05;t=3.77,P<0.01)。结论 EGCG通过下调胃癌细胞VEGF的表达,而抑制IL-6诱导的肿瘤血管生成。
Objective To investigate the effect and mechanism of epigallocatechin gallate (EGCG) on IL-6-induced angiogenesis in gastric cancer. Methods AGS gastric cancer cell lines were cultured with 50 ng / mL IL-6 or different concentrations of EGCG. The expression of vascular endothelial growth factor (VEGF) in gastric cancer cells was detected by Western blot. The VEGF protein level in tumor cell culture medium was detected by Elisa method. The expression of VEGF mRNA in gastric cancer cells was detected by RT-PCR. The conditioned medium of gastric cancer was used to culture the vascular endothelial cells. The proliferation of vascular endothelial cells was detected by MTT assay. The formation of tubular in vitro was assayed by tubulointerstitial assay. Detect in vivo blood vessel formation. Results IL-6 induced a 2.4-fold increase in the expression of VEGF protein and a 2.8-fold increase in VEGF protein expression in gastric cancer cells, while VEGF mRNA expression increased 3.1-fold. EGCG inhibited VEGF expression and secretion in a dose-dependent manner in gastric cancer cells VEGF mRNA expression. VEGF neutralizing antibody and EGCG could significantly inhibit IL-6-induced vascular endothelial cell proliferation (t = 3.02, P <0.01; t = 2.56, P <0.05) and tubule formation in vitro (t = 3.38, = 3.61, P <0.01) and in vivo angiogenesis (t = 2.66, P <0.05; t = 3.77, P <0.01). Conclusion EGCG can inhibit IL-6-induced tumor angiogenesis by down-regulating the expression of VEGF in gastric cancer cells.