TAZ促进胃癌中血管生成及相关机制的研究

TAZ promoting angiogenesis and its mechanism in gastric cancer

目的:探究Hippo通路关键效应分子TAZ在胃癌组织中的表达及其在胃癌血管生成中的作用。方法:通过免疫组织化学法分析150例胃癌组织标本中TAZ和β-catenin的表达情况;将TAZ过表达质粒及干扰质粒通过慢病毒分别转染至胃癌细胞系MGC803和MKN28中,通过细胞功能实验检测内皮细胞成管、增殖及迁移能力;使用Western blot法检测转染后的胃癌细胞中TAZ及β-catenin的表达情况;采用酶联免疫吸附试验(ELISA)检测TAZ转染后血管内皮生长因子(vascular endothelial growth factor,VEGF)蛋白表达的变化。结果:免疫组织化学法结果显示150例胃癌组织中,TAZ阳性表达64例(阳性率43%),主要定位于细胞核,其表达与肿瘤分级、TNM分期、转移及微血管密度(microvessel density,MVD)有关(P<0.05)。此外,在TAZ阳性组中β-catenin阳性表达率为67.2%,明显高于TAZ阴性组,TAZ的表达与β-catenin呈正相关。在MKN28细胞系中上调TAZ的表达,与HUVEC细胞共培养后增强了内皮细胞增殖及管道形成能力,此外还通过促进β-catenin的表达,增强了内皮细胞的迁移能力;相反,在MGC803细胞系中下调TAZ的表达,与HUVEC共培养后减弱了内皮细胞增殖和管道形成能力,此外还通过降低β-catenin的表达,抑制了内皮细胞的迁移能力。结论:胃癌细胞TAZ的高表达可能通过促进β-catenin和VEGF的表达,进而增强胃癌血管生成能力。

Objective:To determine the expression of TAZ and its role in angiogenesis in gastric carcinoma.Methods:Immunohistochemical staining was performed to investigate the expression of TAZ and to determine whether a direct relationship exists between TAZ andβ-catenin.Transfection with TAZ overexpression plasmid in MKN28 cells was conducted to induce exogenous expression of TAZ and a TAZ knockdown plasmid was transfected into MGC803 cells to reduce TAZ levels.The effects on endothelial cell formation,proliferation,and migration were determined by Matrigel three-dimensional culture,MTT proliferation assay and Transwell migration assay.In addition,the expression of TAZ andβ-catenin in transfected gastric cancer cells was detected by Western blot.Results:Immunohistochemistry showed that TAZ protein was expressed in 64 of 150 gastric cancer sample tissues(43%),TAZ was localized in the nucleus,and its expression was associated with tumor grade,TNM stage,metastasis,and microvessel density(MVD)(P<0.05).In addition,the expression frequency ofβ-catenin in the TAZ positive group was 67.2%,which was significantly higher than that in the TAZ negative group,and the expression of TAZ was positively correlated with β-catenin.After transfection,TAZ overexpression increased the expression of β-catenin and enhanced HUVECs tube formation,proliferation,and migration.In the MGC803 cells transfected with the knockdown plasmid,β-catenin levels were decreased and HUVECs motility was inhibited.Conclusions:TAZ may promote angiogenesis in gastric cancer by promotingβ-catenin expression.