Background and purpose:More and more evidence has showed that Grb2 binding protein-2 (Gab2) is associated with tumor invasion and metastasis. However, the relationship between Gab2 and epithelial-mesenchymal transition (EMT) in breast cancer is not clear. The aim of this study is to investigate the effect of Gab2 on EMT markers and the mechanism of Gab2 on breast cancer invasion and metastasis.Methods:Immunohistochemical methods were used to detect the expressions of Gab2, E-cadherin and vimentin in 80 cases of breast cancer tissues, and the correlations between them were analyzed. Western blot was used to detect the expression of Gab2 in breast tissues. After MDA-MB-231 cells were transfected with siRNA plasmid, wound healing assay was used to detect the invasive ability of transfected cells induced by epithelial growth factor (EGF) in vitro. Then Western blot was used to analyze the protein expressions of E-cadherin, vimentin, phosphorylated GSK-3β (p-GSK-3β) and nuclear Snail.Results:Gab2 was negatively correlated with the expression of E-cadherin and positively correlated with the expression of vimentin in breast cancer tissues (P<0.05). The expression of Gab2 in breast cancer tissues was higher than that in normal breast tissues adjacent to breast cancer. In vitro, Gab2 expression was significantly knocked down in MDA-MB-231 cells transfected with Gab2 siRNA plasmid (SiGab2/MDA-MB-231cells). Meanwhile, the invasive ability of SiGab2/MDA-MB-231cells was decreased with EGF stimulation. The expression of E-cadherin was increased in SiGab2/MDA-MB-231cells. However, the expressions of vimentin, p-GSK-3β and nuclear Snail were decreased in SiGab2/MDA-MB-231cells.Conclusion:Gab2 can promote the invasion and metastasis of breast cancer by EMT through GSK-3β/Snail signaling pathway.%背景与目的：越来越多的证据显示，Grb2协同结合蛋白2(Grb2 binding protein-2，Gab2)与肿瘤的侵袭转移相关，但Gab2与乳腺癌上皮-间质转化(epithelial-mesenchymal transition，EMT)的关系尚不清楚。本研究旨在探讨Gab2对乳腺癌EMT标志物的影响，明确Gab2在乳腺癌侵袭和转移中的作用机制。方法：采用免疫组织化学染色法检测80例乳腺癌组织中Gab2及EMT标记物上皮性钙黏着蛋白(E-cadherin)、波形蛋白(vimentin)的表达情况并分析其相关性，用蛋白[质]印迹法(Western blot)检测乳腺组织Gab2的表达情况，采用小干扰RNA(siRNA)技术降低乳腺癌细胞系MDA-MB-231中Gab2的表达，采用划痕实验检测表皮生长因子(epithelial growth factor，EGF)刺激后转染细胞的侵袭能力变化，用Western blot检测敲低Gab2后MDA-MB-231细胞中E-cadherin及vimentin的表达情况，同时检测p-GSK-3β的表达情况、转录因子Snail转核情况。结果：Gab2在乳腺癌组织中的表达与E-cadherin的表达呈负相关，而与vimentin的表达呈正相关(P<0.05)；乳腺癌组织中Gab2的表达量明显高于正常乳腺组织；siRNA质粒转染后，SiGab2/MDA-MB-231细胞组中Gab2蛋白的表达量明显降低，结果显示转染成功，划痕实验显示细胞的侵袭能力减弱，表明Gab2影响乳腺癌细胞系的侵袭能力；敲低Gab2后，MDA-MB-231细胞中的E-cadherin的表达明显升高，而vimentin的表达明显降低；GSK-3β的磷酸化受到抑制，而Snail在敲低Gab2的细胞核中的表达明显下调。结论：Gab2可以通过GSK-3β/Snail信号通路促进乳腺癌的EMT，从而促进乳腺癌的侵袭和转移。
展开▼
