中文摘要：

目的：研究RNA干扰人抗原R（human antigenR，HuR）基因的表达对人乳腺癌耐药细胞株MCF-7／Adr对多柔比星（doxombicin）敏感性的影响。方法：构建靶向HuR基因的shRNA表达质粒（pGenesil—siHuR），稳定转染至MCF-7／Adr细胞，real-timePCR检测细胞中MDRl mRNA的表达，Western blotting检测MCF-7／Adr细胞中由MDRl基因编码的P糖蛋白（P—glycoprotein，P—gP）的表达，MTF法检测pGenesil—siHuR转染后MCF-7／Adr细胞在多柔比星作用后的存活率和Ic50，流式细胞术检测MCF-7／Adr细胞的凋亡率。结果：与未转染的MCF-7／Adr细胞比较，pGenesil—siHuR质粒转染MCF-7／Adr细胞中MDRl mRNA的表达水平明显减低[（0．184±0．029）VS（1．203±0．026），P〈0．01]，P—gP表达水平明显降低。pGenesil—siHuR质粒转染MCF-7／Adr细胞后，MCF-7／Adr细胞对多柔比星的Ic50从未转染的（148．2±2．3）nmoI/L降至（42．94-0．4）nmoI/L；经多柔比星处理后，pGenesil—siHuR质粒转染组MCF-7／Adr细胞的凋亡率明显上升[（34．6±1．1）％υs（1．1±0．2）％，P〈0．01]。结论：RNA干扰HuR的表达能抑制MDRl基因的表达，增加耐药乳腺癌MCF-7／Adr细胞对多柔比星的敏感性。

英文摘要：

Objective： To investigate the effect of interference of human antigen R （HuR） expression on sensitivity of human multidrug-resistant human breast cancer MCF-7/Adr cell line to Doxorubicn. Methods： The shRNA expression vector targeting HuR gene （pGenesil-siHuR） has been constructed and stably transfected into human breast cancer MCF-7/Adr cell line. The expression level of MDR1 mRNA in MCF-7/Adr cells was assayed by real-time PCR. The P-gp protein （encoded by the MDR1 gene） expression were determined by Western blotting. The survival rate and ICs0 of MCF-7/Adr cells to doxorubicin after pGenesil-siHuR transfection were evaluated by MTT method. The apoptosis rate of MCF-7/Adr cells was detected by flow cytometry. Results： Compared with untransfected MCF-7/Adr cells, the MDR1 mRNA （ [ 0.184 ± 0. 029 ] vs [ 1. 203 ± 0. 026 ], P 〈 0.01 ） and P-gp protein expressions （ [ 0.314 ± O. 011 ] vs [ 0. 796 ± 0. 007 ], P 〈 0.01 ） were significantly reduced in pGenesil-siHuR transfected MCF-7/Adr cells （ P 〈 O. 01 ）. The IC50 of MCF-7/Adr cells to doxorubicin decreased from （148.2 ± 2.3 ） nmol/L to （42.9 ±O. 4） nmol/L after pGenesil-siHuR transfection. Compared with untransfected MCF-7/Adr ceils, the ratio of cell apoptosis was significantly increased in pGenesil-siHuR transfected MCF-7/Adr cells （ [ 34.6 ＋ 1.1 ] % vs [ 1.1 ± 0.2 ] %, P 〈 0.01 ） after the treatment with doxorubicin. Conclusion ： RNA interference of HuR can inhibit the expression of MDR1 gene and increase the sensitivity of multidrug-resistant breast cancer cells to doxorubicin.