中文摘要：

目的：观察Bmi-1稳定干扰后对乳腺癌细胞药敏性的影响。方法：构建Bmi-1shRNA逆转录病毒表达载体,并用该逆转录病毒感染人乳腺癌细胞,建立Bmi-1稳定干扰的乳腺癌细胞株。采用不同浓度的化疗药物5-氟尿嘧啶和顺铂处理上述细胞,MTT法观察乳腺癌细胞的生长抑制率。结果：免疫印迹检测结果表明Bmi-1稳定干扰的乳腺癌细胞株成功建立。MTT检测显示Bmi-1稳定干扰的乳腺癌细胞（MDA-MB-435S-Bmi-1/RNAi）增殖抑制率显著高于对照细胞（MDA-MB-435S-vector）（P〈0.05）,并且呈浓度依赖性。其中在MDA-MB-435S-vector中5-氟尿嘧啶和顺铂的IC50值分别为1.7233mg/L和2.9065mg/L,而在MDA-MB-435S Bmi-1/RNAi稳定细胞株5-氟尿嘧啶和顺铂中的IC50值分别为0.9733mg/L和1.8563mg/L（P〈0.05）。结论：Bmi-1在乳腺癌细胞对化疗药物敏感性中发挥重要作用,Bmi-1干扰能增加乳腺癌细胞对化疗药物的敏感性。

英文摘要：

Objective：To investigate the effect of Bmi-1 knockdown on the chemosensitivity of breast cancer cells.Methods：pSUPER Retro Bmi-1 RNAi plasmid was constructed successfully.Breast cancer cells were infected with the viral supernatant from the GPG293 cells.The alteration of Bmi-1 expression was examined by Western blot assay.Breast cancer cells were treated with different concentrations of 5-fluorouracil and cisplatin,and the effect of Bmi-1 knockdown on the proliferation of breast cancer cells treated with 5-fluorouracil and cisplatin were measured by MTT assay.Results：MDA-MB-435S-Bmi-1/RNAi and MDA-MB-435S-vector stable cells were successfully established.The growth inhibitory rate of MDA-MB-435S-Bmi-1/RNAi was significantly higher than those in the control group after treatment with different concentrations of 5-fluorouracil and cisplatin for 72 h（P〈0.05）.The IC50 of 5-FU in the MDA-MB-435S-Bmi-1/RNAi and MDA-MB-435S-vector stable cells were 0.9733 mg/L and 1.7233 mg/L（P〈0.05）,respectively;The IC50 of DPP in the MDA-MB-435S-Bmi-1/RNAi and MDA-MB-435S-vector stable cells were 1.8563 mg/L and 2.9065 mg/L（P〈0.05）,respectively.Conclusion：Knockdown of Bmi-1 makes breast cancer cells more sensitive to 5-FU and DPP.