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目的:研究果蝇zeste基因增强子同源物2(enhancer of zeste homolog 2,EZH2)和肝癌缺失基因1(deleted in liver cancer-1,DLC1)在乳腺癌组织及细胞中的表达水平,并探讨二者之间的相互关系。方法:首先采用免疫组织化学法检测120例乳腺癌组织及63例癌旁正常组织中EZH2和DLC1蛋白的表达情况;随后分别采用实时荧光定量PCR法和蛋白质印迹法检测20例乳腺癌以及癌旁正常组织,以及乳腺癌MCF-7和MDA-MB231细胞及正常乳腺上皮细胞HBL100中EZH2和DLC1 mRNA及蛋白的表达水平。通过脂质体法将特异性针对EZH 2基因的siRNA转入MDA-MB231细胞,分别采用实时荧光定量PCR法和蛋白质印迹法检测MDA-MB231细胞中EZH2及DLC1 mRNA和蛋白表达水平的变化。结果:免疫组织化学检测结果提示,EZH2蛋白在乳腺癌组织中的阳性表达率明显高于其在癌旁正常组织中的阳性表达率(P=0.000),DLC1蛋白在乳腺癌组织中的阳性表达率明显低于其在癌旁正常组织中的阳性表达率(P=0.008)。乳腺癌组织中EZH2和DLC1蛋白的阳性表达率与肿瘤大小及淋巴结转移密切相关(P值均<0.05)。实时荧光定量PCR法和蛋白质印迹法检测结果显示,EZH2 mRNA和蛋白在乳腺癌组织和乳腺癌MCF-7和MDA-MB231细胞中的表达水平均明显高于癌旁正常组织和正常乳腺上皮细胞HBL100(P值均<0.01),而DLC1 mRNA和蛋白的表达水平均明显低于癌旁正常组织和正常乳腺上皮细胞HBL100(P值均<0.01)。沉默MDA-MB231细胞中EZH 2基因表达后,DLC1 mRNA及蛋白的表达水平均明显上调(P值均<0.05)。结论:EZH2与DLC1在乳腺癌中的表达呈负相关,抑制EZH2的表达可以恢复DLC1的表达,提示EZH2可能通过抑制DLC1的表达促进肿瘤的发生和发展。
Objective: To investigate the expression of Drosophila zeste homolog 2 (EZH2) and deleted in liver cancer-1 (DLC1) in breast cancer tissues and cells The relationship between the two. Methods: The expression of EZH2 and DLC1 in 120 cases of breast cancer tissues and 63 cases of adjacent normal tissues were detected by immunohistochemical method. Then the expression of EZH2 and DLC1 protein in 20 cases of breast cancer and adjacent normal tissues were detected by real-time fluorescence quantitative PCR and Western blot, respectively Normal tissues and the expression of EZH2 and DLC1 mRNA and protein in breast cancer MCF-7 and MDA-MB231 cells and normal breast epithelial cells HBL100. The specific siRNA against EZH2 gene was transfected into MDA-MB231 cells by liposome method. The mRNA and protein expression of EZH2 and DLC1 in MDA-MB231 cells were detected by real-time fluorescence quantitative PCR and Western blot respectively. Results: Immunohistochemical results showed that the positive expression rate of EZH2 protein in breast cancer tissues was significantly higher than that in normal adjacent tissues (P = 0.000). The positive expression of DLC1 protein in breast cancer tissues The positive rate was significantly lower than that in the adjacent normal tissues (P = 0.008). The positive expression rates of EZH2 and DLC1 in breast cancer tissues were closely related to tumor size and lymph node metastasis (all P <0.05). The results of real-time fluorescence quantitative PCR and Western blotting showed that the expression level of EZH2 mRNA and protein in breast cancer and breast cancer MCF-7 and MDA-MB231 cells were significantly higher than that in the adjacent normal tissues and normal breast epithelial cells HBL100 (All P <0.01). However, the expression of DLC1 mRNA and protein were significantly lower than those in normal tissues and normal breast epithelial cells (P <0.01). After EZH 2 gene silencing in MDA-MB231 cells, the expression of DLC1 mRNA and protein were significantly up-regulated (all P <0.05). CONCLUSION: The expression of EZH2 and DLC1 in breast cancer is negatively correlated. Inhibition of EZH2 expression can restore the expression of DLC1, suggesting that EZH2 may promote the development and progression of tumors by inhibiting the expression of DLC1.