Abstract:Objective：To construct the small interfering RNA (siRNA) eukaryotic expression vector specific for human CXCR4 gene and to observe its silencing effects on CXCR4 gene. Methods：The expression vectors of pSUPER/ CXCR4siRNA1 and the control group pSUPER/ CXCR4siRNA0 were constructed by gene recombination, and then were transfected by liposome mediated into the MDAMB231 breast cancer cells with high metastasis potential . The expression of CXCR4 mRNA and protein was detected. Results：The eukaryotic expression vectors of pSUPER/ CXCR4siRNA1 ,which downregulated mRNA and protein of CXCR4 at 72 h after transfection, were successfully constructed. The inhibitory effects of pSUPER/CXCR4 siRNA1 was obvious stastictically. Conclusions：Eukaryotic expression vector of siRNA specific for CXCR4 is successfully constructed and has inhibitory effects obviously, which can provide the experimental basis for its application in the treatment of breast cancer.