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目的探讨雌激素受体(ER)在MCF-7乳腺癌细胞他莫昔芬耐药中的作用。方法建立ERα基因沉默的MCF-7细胞株(A组)和ERβ基因沉默的MCF-7细胞株(B组),以亲本MCF-7为阴性对照,MTT法检测MCF-7乳腺癌细胞对他莫昔芬的耐药性,RT-PCR检测耐药相关基因:多药耐药基因1(MDR1)、肺耐药相关蛋白(LRP)、π类谷胱甘肽S-转移酶(GST-π)等的表达水平,Western blotting检测耐药相关的蛋白激酶B(AKT)、细胞外调节蛋白激酶(ERK)等的表达水平。结果与亲本MCF-7细胞株(C组)对比,ERα基因沉默的MCF-7细胞株(A组)细胞株增强了他莫昔芬对肿瘤细胞增殖的抑制率(P<0.05),ERβ基因沉默的MCF-7细胞株(B组)细胞株降低了他莫昔芬对肿瘤细胞增殖的抑制率(t=8.23,48.36,78.57,P<0.05)。与C组比较,A组耐药基因MDR1、LRP、GST-π的表达水平显著降低(P<0.05),B组耐药基因MDR1、LRP、GST-π表达水平显著增加(P<0.05)。与C组比较,A组能够显著抑制AKT及ERK的磷酸化,降低p-AKT及p-ERK的表达水平(P<0.05),B组能够显著促进AKT及ERK的磷酸化,增加p-AKT及p-ERK的表达水平(P<0.05)。结论雌激素受体在乳腺癌的耐药性中发挥重要作用,ERβ可能通过抑制相关耐药基因及蛋白表达从而降低了TAM的耐药性,ERβ可能成为肿瘤治疗的有效靶点。
Objective To investigate the role of estrogen receptor (ER) in the resistance to tamoxifen in MCF-7 breast cancer cells. Methods A MCF-7 cell line with silencing of ERα gene (group A) and a MCF-7 cell line with silencing of ERβ gene (group B) were established. MCF-7 breast cancer cells were detected by MTT assay Moxifen resistance, RT-PCR detection of resistance-related genes: MDR1, LRP, GST-π ), Etc. Western blotting was used to detect the expression of drug-resistant protein kinase B (AKT) and extracellular regulated protein kinase (ERK). Results Compared with the parental MCF-7 cell line (group C), the cell line MCF-7 (group A) with ERα gene silencing enhanced the inhibitory effect of tamoxifen on the proliferation of tumor cells (P <0.05) Silencing cell lines of MCF-7 cells (group B) reduced the inhibition rate of tamoxifen on tumor cell proliferation (t = 8.23,48.36,78.57, P <0.05). Compared with group C, the expression of MDR1, LRP and GST-π in group A was significantly decreased (P <0.05), and the expression of MDR1, LRP and GST-π in group B was significantly increased (P <0.05). Compared with group C, group A could significantly inhibit the phosphorylation of AKT and ERK and decrease the expression of p-AKT and p-ERK (P <0.05). Group B could significantly promote the phosphorylation of AKT and ERK and increase the expression of p-AKT And p-ERK expression (P <0.05). Conclusion The estrogen receptor plays an important role in the drug resistance of breast cancer. ERβ may reduce the drug resistance of TAM by inhibiting the expression of related drug resistance genes and proteins. ERβ may be an effective target for tumor therapy.