乳腺癌组织Beclin1和EMT相关分子标志物表达及其临床意义探讨

Expressions and clinical significance of Beclin1 and markers of EMT in breast carcinoma tissues

目的探讨乳腺癌组织Beclin1和上皮-间质转化(epithelial-mesenchymal transition,EMT)相关分子标志物(E-cadherin,N-cadherin)表达及其临床意义。方法采用实时荧光定量PCR(Real-time PCR)、免疫组织化学和蛋白质印迹法分别检测2012-12-01—2013-06-01南方医科大学珠江医院收治的67例乳腺癌和正常乳腺组织标本中Beclin1及E-cadherin、N-cadherin的mRNA和蛋白表达情况,分析Beclin1与EMT及临床病理学特征的关系。结果乳腺癌组织和正常乳腺组织中Beclin1mRNA的表达量分别为2.194±0.502和5.637±1.445,z=-6.806,P<0.001;E-cadherin mRNA的表达量分别为2.647±0.717和6.538±2.045,z=-5.088,P=0.009;N-cadherin mRNA的表达量分别为6.501±0.741和3.860±0.955,z=5.928,P<0.001。Beclin1蛋白定位于胞膜和胞质,以胞质为主;E-cadherin蛋白定位于胞膜和胞质,以胞膜为主;N-cadherin蛋白定位于胞膜和胞质,以胞质为主。乳腺癌组织和正常乳腺组织中Beclin1蛋白表达量分别为5.531±0.848和7.871±0.817,z=-5.431,P<0.001;E-cadherin蛋白的表达量分别为1.257±0.142和2.885±0.294,z=-4.904,P<0.001;N-cadherin蛋白表达量分别为0.802±0.072和0.419±0.049,z=4.453,P<0.001。Beclin1蛋白是EMT的保护因素,Beclin1蛋白与人类表皮生长因子受体(human epidermal growth factor 2,HER-2)、Ki-67和TNM分期呈负相关性,P值均<0.05;与年龄、组织分级、雌激素受体(estrogen receptor,ER)和孕激素受体(progestrone receptor,PR)无相关关系。结论无论mRNA水平还是蛋白质水平,乳腺癌组织中Beclin1和E-cadherin较正常乳腺组织表达均下调,N-cadherin较正常乳腺组织表达上调。Beclin1是EMT的保护因素,Beclin1与HER-2、Ki-67和TNM分期均存在负相关关系,可作为乳腺癌的预后指标,对进一步研究乳腺癌的远处转移机制提供理论参考。

OBJECTIVE To investigate expressions and clinical significance of Beclin1 and markers of EMT in breast cancer tissues.METHODS The expressions of Beclin1,E-cadherin and N-cadherin were detected in 67 patients with breast cancer by Real-time PCR,immunohistochemistry and Western blot.The relationship between the expression of Beclin1 and EMT and the correlation of Beclin1 with clinical-pathologic features of breast cancer were analyzed.RESULTS The expression of Beclin1 mRNA in breast cancer tissues was 2.194±0.502,which was lower than that of in normal breast tissue,5.637±1.445（z=-6.806,P〈0.001）.The expression of E-cadherin mRNA in breast cancer was2.647±0.717,which was lower than that of normal breast tissue（6.538±2.045,z=-5.088,P=0.009）.The expression of N-cadherin mRNA in breast cancer was 6.501±0.741,which was higher than that of in normal breast tissue（3.860±0.955,z=5.928,P〈0.001）.Beclin1 and N-cadherin were located in the cell membrane,cytoplasm,mainly in the cytoplasm.E-cadherin was located in the cell membrane,cytoplasm,mainly in the membrane.The expression of Beclin1 protein in breast cancer was 5.531±0.848,which was lower than that of in normal breast tissue（7.871±0.817,z=-5.431,P〈0.001）.The expression of E-cadherin protein in breast cancer was 1.257±0.142,which was lower than that of in normal breast tissue（2.885±0.294,z=-4.904,P〈0.001）.The expression of N-cadherin protein in breast cancer was 0.802±0.072,which was higher than that of in normal breast tissue（0.419±0.049,z=4.453,P〈0.001）.Beclin1 protein was a protective factor for EMT.Beclin1 protein was negatively correlated with HER-2,Ki-67,TNM staging（P〈0.05）and not correlated with age,tumor grade,ER and PR.CONCLUSIONS At both mRNA and protein level,the expressions of Beclin1 and E-cadherin are lower than those in in normal breast tissue,and N-cadherin is higher than that inormal breast tissue.Beclin1 protein is a protective factor for EMT.Beclin1 protein is negatively correlated with HER-2,Ki-67,TNM staging.It could be a marker for clinical prognosis.This may offer theoretical reference for the continue study of breast cancer metastasis.