ER拮抗剂逆转乳腺癌多药耐药的实验研究

ER Antagonist Reverses the Multidrug Resistance of Human Breast Cancer Cells

目的探讨ER拮抗剂（ICI 182，780）对人乳腺癌紫杉醇（PTX）耐药细胞株MCF-7／PTX耐药逆转的作用及其相关机制。方法应用Western印迹方法检测MCF-7／PTX细胞多药耐药基因（MDRl）编码的P-糖蛋白（P-gp）的表达；应用荧光酶标仪检测MCF-7／PTX细胞R-123外排。反映P-gp的泵功能；应用四甲基偶氮唑蓝（MTT）法检测不同浓度ICI 182，780及化疗药物（PTX、EPI、VCR）对MCF-7／PTX细胞的增殖抑制效应，并计算半数抑制浓度（IC50）；应用RT—PCR检测无毒剂量ICI182，780对MCF-7／PTX细胞内MDR1表达水平的影响。结果P-gp在MCF-7／PTX细胞较MCF-7细胞表达增高；无毒剂量ICI182，780通过降低MCF-7／PTX细胞内MDRl表达水平发挥耐药逆转作用;MCF-7／PTX细胞对PTX、ADR和VCR的耐药性较MCF-7细胞强，加入ICI182，780能增强MCF-7／PTX细胞对化疗药物的敏感性。结论ER拮抗剂ICI182，780可部分逆转人乳腺癌耐药细胞株MCF-7／PTX细胞对PTX、EPI和VCR的耐药性，其逆转机制与抑制MDRI的表达有关。

Objective To investigate the reversal effect of the ER antagonist （ICI 182, 780） in a paclitaxel-resistant human breast cancer cell line MCF-7/PTX. Methods The expression of P- gp, encoded by MDR1 gene, was determined by Western blotting. The R-123 excretion, indicative of P-gp pump function, was detected in MCF-7/PTX cells by the fluorescence microplate assay. MTT assay was used to measure the effect of ICI182, 780 of different concentrations and multiple chemotherapy drugs （PTX, EPI and VCR） on the proliferation of MCF-7/PTX cells and the IC50 values were calculated. The expression level of MDR1 mRNA in MCF-7/PTX cells treated with ICI 182, 780 was assessed by RT-PCR. Results P-gp protein was significantly increased in MCF-7/PTX cells compared with parental MCF-7 cells. MCF-7/PTX cells exhibited higher resistance to PTX, EPI, and VCR compared with MCF-7 cells. ICI 182, 780 could enhance the sensitivity of MCF-7/PTX cells to chemotherapeutic drugs and decrease the expression of P-gp and MDR1 mRNA level. Conclusions ICI 182, 780 can reverse the multidrug resistance of MCF-7/PTX cells partially by decreasing the expression of MDR1 gene.