siRNA against survivin coupling with epirubicin enhances to induce breast cancer cell MCF-7 to apoptosis

Objective: To use the sequence-specific siRNA knocking down the expressions of Survivin gene and inducing breast cancer MCF-7 cell line to apoptosis, and to couple the siRNA with Survivin for investigating the effects of MCF-7 cell induced to apoptosis and the chemotherapy sensitivity of breast cancer cell treated to epirubicin. Methods: The molecular cloning technique was applied to construct the eukaryotic expression vector of siRNA against Survivin, and lipofectamine™ 2000 was used to transfect MCF-7 cell. Survivin expressions were detected by semi-quantitive RT-PCR and immunohistochemical SABC methods. The effects of inducing MCF-7 cell apoptosis and enhanced chemotherapy sensitivity to epirubicin were assessed by TUNEL method. Results: The sequence-specific siRNA can, effectively and specifically, knock the expressions of Survivin gene down at both mRNA and protein levels, in which the expression inhibition rates were 64.91% and 79.72% respectively. After 48 h, 8.75% cells transfected with siRNA expression vector were induced to apoptosis; Coupling siRNA against Survivin with epirubicin can induce the cell apoptosis rate up to 24.21%. Conclusions: In the study, the siRNA against Survivin can, effectively and specifically, decrease the expressions of Survivin gene in MCF-7 cell; blocking the expressions of Survivin can, in certain degree, induce MCF-7 cell to apoptosis and enhance cell chemotherapy sensitivity to epirubicin significantly; Survivin RNAi has a great potential value in the gene therapy of breast cancer.