miR-106b在胃癌中对BTG3蛋白表达的调控机制

Regulation mechanisms of BTG3 protein expression in gastric cancer by miR-106b

目的探讨BTG3蛋白在胃癌发生、发展中的作用及其在胃癌中表达的调控机制。方法免疫组化检测胃癌、癌旁、癌前病变组织及对照组织石蜡标本中BTG3蛋白表达情况;qRT-PCR检测胃癌细胞BTG3和miR-106b表达,Western blotting检测转染miR-106b模拟剂和miR-106b抑制剂后胃癌细胞中BTG3蛋白表达水平,荧光素酶报告基因实验验证miR-106b在胃癌细胞中对BTG3的调控。结果免疫组化结果:BTG3蛋白在胃癌组表达率32.50%,明显低于其余各组,差异有统计学意义(P<0.05),且与胃癌肿瘤分期(P=0.041)及分化程度(P=0.021)有显著相关性,H.pylori阳性胃癌组BTG3蛋白表达率明显低于H.pylori阴性胃癌组(P=0.017);qRT-PCR结果提示,胃癌细胞中BTG3低表达,而miR-106b高表达;Westen blotting结果显示,转染miR-106b模拟剂或miR-106b抑制剂的胃癌细胞BTG3蛋白表达水平相应降低或升高,荧光素酶报告实验显示,转染miR-106b模拟剂后野生型BTG3-3′UTR报告质粒荧光素酶活性降低(P<0.001)。结论BTG3在胃癌低表达,与胃癌分期及分化程度相关,与H.pylori感染可能有关,miR-106b在胃癌中高表达,可能通过靶向调控BTG3发挥作用。

Objective To investigate the regulation mechanisms of BTG3 expression in gastric cancer. Methods Immunohistochemistry was used to detect the difference of BTG3 protein expression in paraffin specimens of gastric cancer,paracancer,precancerous lesion and control tissues.The expressions of BTG3 and miR-106b in gastric cancer cells were detected by qRT-PCR.BTG3 protein expressions in gastric cancer cells transfected with miR-106b mimic and inhibitor were detected by Western blotting analysis,and luciferase reporter gene assay was used to verify the regulation of miR-106b on BTG3 in gastric cancer cells. Results Immunohistochemical results showed that the positive expression rate (32.50%) of BTG3 protein in gastric cancer group was lower ( P <0.05),and significantly correlated with tumor stage ( P =0.041) and differentiation degree ( P =0.021),and BTG3 protein expression in the H.pylori positive tissues was lower,difference was statistically significant ( P =0.017).qRT-PCR results suggested that BTG3 was lower in gastric cancer cells,while miR-106b was higher.Westen blotting results showed that the expression level of BTG3 protein in gastric cancer cells transfected with miR-106b mimic was increased or dereased in gastric cancer cells accordingly.Luciferase reporter assays showed that wild-type BTG3-3′UTR reporter plasmid luciferase activity was significantly reduced after transfection with miR-106b mimic ( P <0.001). Conclusion The low expression of BTG3 in gastric cancer is related to the staging and differentiation of gastric cancer,and may be associated with H.pylori infection.BTG3 is targeted and regulated by miR-106b in gastric cancer cells.