中文摘要：

[目的]探讨沉默SALL4基因对乳腺癌耐药细胞MCF-7/A的增殖及化疗敏感性的影响。[方法]q RT-PCR和Western Blot实验检测MCF-7、MCF-7/A细胞内SALL4表达水平,运用慢病毒包装sh RNA方法沉默MCF-7/A细胞的SALL4基因;实验组（Lv-sh SALL4）、阴性对照组（Lv-sh NC）和空白对照组（CON）。CCK8法、克隆形成实验检测SALL4沉默对细胞增殖能力的影响;CCK8法检测表柔比星处理细胞24h和48h的半数抑制浓度（IC_（50））;流式细胞仪检测细胞凋亡。[结果]SALL4在MCF-7/A细胞中的表达水平显著高于MCF-7（P〈0.05）。MCF-7/A细胞中SALL4基因被成功沉默,病毒感染MCF-7/A细胞72h后,细胞感染效率约95%,沉默SALL4基因后MCF-7/A细胞内SALL4 m RNA及蛋白表达均明显降低（P〈0.05）。沉默MCF-7/A细胞的SALL4基因,显著抑制了细胞的增殖能力（P〈0.05）,增强了细胞对表柔比星的敏感性;表柔比星24h和48h的IC_（50）均明显降低（P〈0.05）,并且表柔比星诱导的细胞凋亡增加（P〈0.05）。[结论 ]沉默SALL4基因能够抑制乳腺癌耐药细胞MCF-7/A的增殖,增强耐药细胞对表柔比星的敏感性。SALL4基因沉默可能是乳腺癌治疗的新靶点。

英文摘要：

[Purpose] To investigate the effect of SALL4 gene silencing on the cellular proliferation and sensitivity of human breast cancer cell line MCF-7/A to chemotherapy. [Methods] The m RNA and protein levels of SALL4 in MCF-7 and MCF-7/A cells were examined by q RT-PCR and Western Blot,respectively. The lentivirus-mediated sh RNA approach was applied to silence the SALL4 gene of MCF-7/A cells. The experiment set up an experimental group（Lv-sh SALL4）,the negative control group（Lv-sh NC） and blank control group（CON）.The inhibitory effect on proliferation of MCF-7/A cells were detected by CCK8 assay and colony formation. Groups of CON,Lvsh NC and Lv-sh SALL4 were cultivated with various concentrations of Epirubicin for 24 h and 48 h.Then,the IC（50）values（the concentration of drug inhibiting 50% of the cells） of MCF-7/A at 24 h and48h were measured by CCK8 regent kit and the cell apoptosis rate was detected by flow cytometry.[Results] SALL4 obviously up-regulated in MCF-7/A cells,compared with to MCF-7 cells（P〈0.05）.SALL4 gene in MCF-7/A cells was successfully silenced by the lentivirus-mediated sh RNA interference approach. After being transfected for 72 h,the infection efficiency was about 95%.And both m RNA and protein levels of SALL4 in Lv-sh SALL4 group were significantly reduced（P〈0.05）.CCK8 assay based growth curve and colony formation assay indicated that silencing SALL4 significantly inhibited the proliferation of MCF-7/A cells（P〈0.05）.Besides,down-regulation SALL4 markedly increased the sensitivity of MCF-7/A cells to Epirubicin.IC（50） value of Epirubicinin Lvsh SALL4 group was significantly lower at 24 h and 48 h based on CCK8 assay（P〈0.05）.The cell apoptosis rate was higher in Lv-sh SALL4 group than that in CON group after cultivating with Epirubicin for 48h（P〈0.05）. [Conclusion] Silencing the SALL4 gene in MCF-7/A can inhibit the proliferation and enhance the chemotherapy sensitivity of drug resistant breast cancer cells MCF-7/A,towards Epirubicin.It sugge