中文摘要：

目的：为探索治疗乳腺癌新途径，研究RNA干扰（RNA interferance，RNAi）对MCF-7细胞株WT 1基因表达的抑制作用。方法：设计制备多对针对WT 1基因的小干扰RNA（small interfering RNA，siRNA），转染MCF-7细胞，采用实时定量PCR（real—time quantitative polymerase chainreaction，RQ-PCR）法测定WT1 mRNA的表达，western blot测定WT1蛋白的表达，流式细胞仪检测加入长春新碱后的MCF-7细胞凋亡率。结果：siRNA能有效抑制WT1基因的表达，但不呈剂量关系，在较低浓度可维持RNAi至少4d时间，WT1基因表达下调的MCF-7细胞凋亡率增加。结论：RNAi能有效抑制MCF-7细胞中WT1基因的表达，同时转染siRNA后细胞对长春新碱敏感。

英文摘要：

Objective：To investigate the inhibitory effect of RNA interference （RNAi） on WT 1 gene expression in MCF-7 cell line. Methods： Several pairs of small interfering RNA （siRNA） for WT 1 gene was designed and transfected into MCF-7 cells. WT1 gene expression was assessed by real-time quantitative polymerase chain reaction （RT-PCR）, and WT1 protein expression was tested by western blotting. Results： Expression of WT 1 gene can be effectively suppressed by siRNA in a concentration-independent manner. RNAi could be maintained at low concentration, for example at 10 nmol/L, for at least 4 d. Conelusions：Expression of WT1 gene can be effectively inhibited by siRNA in MCF-7 cells. Simultaneous transfection with siRNA increases the sensitivity of MCF-7 cells to vincristine.