δ-catenin通过PI3K/AKT信号通路促进乳腺癌细胞上皮间质转化的机制研究

The mechanism research of δ-catenin promoting epithelial mesenchymal transition of breast cancer cells through PI3K/AKT signaling pathway

目的探讨δ-catenin通过PI3K/AKT信号通路促进乳腺癌细胞上皮间质转化(epithelial-mesenchymal transition,EMT)的作用机制,为乳腺癌的靶向治疗提供科学依据。方法选取人乳腺癌细胞系MDA-MB-231,对细胞进行不同处理后分为3组,分别为过表达组(δ-catenin)、LY294002组(δ-catenin+LY)和对照组,δ-catenin组处理方法为δ-catenin表达质粒转染入乳腺癌细胞系,δ-catenin+LY组为LY294002和δ-catenin表达质粒与乳腺癌细胞系共同孵育48 h,对照组为空白质粒转染入乳腺癌细胞系。应用Western blotting方法、PI3K/AKT通路抑制剂LY294002和侵袭实验后,分别比较δ-catenin组、δ-catenin+LY组与对照组的EMT(上皮性标记E-cadherin指标、间叶性标记N-cadherin和Vimentin指标)、信号通路蛋白(AKT、p-AKT)、内参照β-actin蛋白以及肿瘤侵袭能力(穿过微孔膜的肿瘤细胞数量等)的差异。结果δ-catenin组上皮性标记E-cadherin与对照组相比明显减少[(0.62±0.04)比(1.09±0.08)],间叶性标记N-cadherin、Vimentin和p-AKT表达水平明显增加[(1.52±0.08)比(0.51±0.04),(1.02±0.07)比(0.27±0.06),(1.43±0.07)比(0.69±0.11),P<0.05]。δ-catenin组穿过微孔膜的肿瘤细胞数量显著高于对照组[(39.18±4.28)比(9.32±1.36),P<0.05]。δ-catenin+LY组p-AKT表达水平与对照组相比明显减少[(0.21±0.03)比(0.49±0.08),P<0.05];δ-catenin+LY组与对照组在E-cadherin、N-cadherin、Vimentin的表达水平和穿过微孔膜的肿瘤细胞数量比较,差异均无统计学意义(P>0.05)。结论δ-catenin可能通过激活PI3K/AKT通路而促进乳腺癌细胞的EMT和侵袭能力的增强。

Objective To explore the mechanism ofδ-catenin promoting epithelial-mesenchymal transition(EMT)of breast cancer cells through PI3K/AKT signaling pathway,and provide scientific basis for targeted therapy of breast cancer.Methods The human breast cancer cell line MDA-MB-231 were selected,after different treatment,the cells were divided into three groups,namely the over-expression group(δ-catenin),LY294002 group(δ-catenin+LY)and control group(control).Theδ-catenin group was transfected into breast cancer cell lines withδ-catenin expression plasmid,theδ-catenin+LY group was co-incubated with breast cancer cell lines with LY294002 andδ-catenin expression plasmid for 48 h,while the control group was transfected into breast cancer cell lines with blank plasmid.Western blotting,PI3K/AKT pathway inhibitor LY294002 and invasion experiment were used to compare EMT(epithelial marker E-cadherin index,mesenchymal marker Ncadherin and Vimentin),signal pathway proteins(AKT,p-AKT),internal referenceβand tumor invasion ability amongδ-catenin group,δ-catenin+LY group and control group,respectively.Results Compared with the control group,the epithelial marker E-cadherin inδ-catenin group decreased significantly[(0.62±0.04)vs.(1.09±0.08)],and the expression levels of mesenchymal markers N-cadherin,Vimentin and p-AKT increased significantly[(1.52±0.08)vs.(0.51±0.04),(1.02±0.07)vs.(0.27±0.06),(1.43±0.07)vs.(0.69±0.11)],the differences were statistically significant(all P<0.05).The number of tumor cells passing through the microporous membrane in theδ-catenin group was significantly higher than that in the control group[(39.18±4.28)vs.(9.32±1.36)],and the difference was statistically significant(P<0.05).Compared with control group,the expression level of p-AKT inδ-catenin+LY group decreased significantly[(0.21±0.03)vs.(0.49±0.08),P<0.05].The differences of expression levels of E-cadherin,N-cadherin and Vimentin and the number of tumor cells passing through microporous membrane betweenδ-catenin+LY group and control group had no statistical significance(all P>0.05).Conclusionsδ-catenin may promote the enhancement of EMT and invasive ability of breast cancer cells by activating PI3K/AKT pathway.