TAZ促进胃癌中血管生成及相关机制的研究

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。

TAZ promoting angiogenesis and its mechanism in gastric cancer

  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 and β-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 and β-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 of β-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 promoting β-catenin expression.