TGF-β1/Smad7信号通路在哈萨克族食管癌上皮间质转化中的作用

Activation of TGF-β1/Smad7 Signaling in Kazakh's ESCC through Epithelial-Mesenchymal Transition

【目的】探讨TGF-β1/Smad7信号通路在哈萨克族食管鳞癌上皮间质转化(EMT)中的作用及其机制。【方法】运用免疫组织化学方法检测50例哈萨克族食管鳞癌组织及远端对应癌旁组织中TGF-β1与Smad7蛋白的表达。进一步在细胞水平,针对食管鳞癌细胞系Ec9706,基于RNA干扰技术,使用Lipofectamine TM 2000试剂转染TGF-β1 si RNA。采用q RTPCR技术检测TGF-β1及Smad7 m RNA表达水平;Western blot技术检测转染后各组TGF-β1、Smad7以及EMT相关蛋白表达水平;MTT、划痕及流式细胞术等方法检测各组细胞转染后的增殖、迁移、凋亡及周期的变化。【结果】免疫组化检测结果显示,哈萨克族食管鳞癌组织中TGF-β1蛋白表达明显高于癌旁组织(P<0.05);Smad7蛋白在食管鳞癌组织中的表达低于癌旁组织(P<0.05)。转染TGF-β1 si RNA后,Ec9706细胞中TGF-β1 m RNA和蛋白表达量均降低,Smad7 m RNA和蛋白表达量增加;上皮标志物E-cadherin表达量增加,间质标志物Vimentin表达量降低,同时Ec9706细胞增殖、迁移受到抑制,细胞凋亡增加,细胞周期发生G0/G1期阻滞。【结论】哈族食管鳞癌中存在TGF-β1/Smad7信号通路的激活,食管癌中TGF-β1高表达,抑制了Smad7的表达,从而促进了上皮间质转化过程,进一步促进了食管癌细胞的增殖和迁移,并抑制细胞凋亡,影响细胞周期中的G0/G1期。

【Objective】 To investigate the effects and mechanism of TGF-β1/Smad7 signaling pathway in Kazakh＇s esophageal squamous cell carcinoma（ESCC） through epithelial-mesenchymal transition（EMT）.【Methods】 Expression of TGF-β1 and Smad7 protein in carcinoma tissues and adjacent normal tissues of 50 Kazakh＇s ESCC patients were detected by immunohistochemistry（IHC）.Based on RNA interference technology,Ec9706 cell was transfected with TGF-β1 si RNA,using LipofectamineTM2000.The m RNA expression level of TGF-β1 and Smad7 were detected by q RT-PCR.Expression of TGF-β1,Smad7 and EMT-associated proteins weremeasured by Western blot after transfection.Then MTT,Wound-healing assay and flow cytometry were performed to detect cell＇s proliferation,migration,apoptosis and cell cycle after transfection.【Results】 The positive rate of TGF-β1 expression in carcinoma tissues of patients with ESCC was significantly higher than non-cancerous adjacent tissue（P〈0.05）,while the positive expression rates of Smad7 in ESCC tissues was significantly lower than the non-cancerous adjacent tissues（P〈0.05）.After transfected with TGF-β1 si RNA,expression of TGF-β1 and Vimentin were significantly decreased,meanwhile,expression of Smad7 and E-cadherin were increased.Furthermore,transfected with TGF-β1 si RNA inhibited cell proliferation,migration and promoted cell apoptosis.【Conclusion】 TGF-β1/Smad7 signaling activated in Kazakh＇s ESCC.TGF-β1 could promote EMT through inhibition of Smad7,consequently promote cell proliferation and migration,influence cell cycle at G0/G1 phase and inhibit the apoptosis of ESCC.