雌激素调控ABCG2介导的乳腺癌MCF-7细胞化疗敏感性

Estrogen regulates ABCG2-mediated chemotherapy sensitivity of MCF-7

目的探讨雌二醇(E2)对乳腺癌耐药蛋白ABCG2表达和乳腺癌MCF-7细胞化疗敏感性的影响。方法用雌激素受体激动剂E2及其拮抗剂TAM(同时也是GPER激动剂)、GPER特异性激动剂G1及其特异性拮抗剂G15分别或联合处理MCF-7细胞,Western blot和免疫荧光法检测MCF-7中ABCG2的蛋白表达量和细胞内定位;用盐酸阿霉素(Dox)处理经上述干预的细胞,流式细胞技术及CCK8法检测细胞对化疗药物敏感性的改变。结果 ABCG2在MCF-7的细胞膜及细胞质均有表达,E2可以上调ABCG2蛋白的表达量(P<0.05),且使胞质内ABCG2向细胞膜移动,并且抑制细胞毒性作用,上述效应能被抑制剂TAM显著抑制(P<0.05);TAM单独处理细胞后ABCG2蛋白表达量减少(P<0.05),GPER特异性激动剂G1同样也抑制ABCG2蛋白的表达(P<0.05),但两者对ABCG2胞膜定位的影响不显著,G1具有增强Dox化疗效能的作用,上述抑制作用均能被特异性抑制剂G15抑制。结论 E2同时激活ER及GPER时起到上调ABCG2的作用,抵抗化疗药物效果,但特异性激活GPER使ABCG2表达量明显减少,提高化疗疗效。

Objective To explore the interaction between ER and GPER in the process of estradiol-mediated regulation of ABCG2 in MCF-7 cells. Methods Western blot and immunoflurescent were used to detect the expression and localization of ABCG2 treated with 1 7-β estradiol（ E2）,G1 respectively or combined with inhibitors. The test cells were treated with doxorubicin（ Dox）,then the change of drug sensitivity was tested by flow cytometry analysis and CCK8 method. Results ABCG2 localizes at both plasma membrane and cytoplasm. E2 upregulates the level of ABCG2 protein and translocates it from cytoplasm to plasma membrane,which result in inhibition to chemotherapy drugs Dox. The relative protein expression of ABCG2 in E2 treatment group was higher than those of the control group（ P〈 0. 0 5）. Above-mentioned changes were blocked by E2 antagonist（ TAM）（ P〈 0. 0 5）. The expression of ABCG2 was both downregulated in TAM and GPER specific angonist（ G1） treatment groups（ P〈 0. 0 5）. Cytotoxic of Dox was improved in those groups as well（ P〈 0. 0 5）. The relative protein expression of ABCG2 was lower and blocked by GPER specific antagonist（ G15）. Conclusions Estradiol upregulates the expression of ABCG2 and inhibites the efficacy of chemotherapy drugs in the case of activate ER and GPER simultaneously. Acivation of GPER improves the efficacy of chemotherapy.