Objective To investigate the effects of siRNA against survivin combined with the neoadjuvant chemotherapy (paclitaxel and epirubicin) on the apoptosis in breast cancer MCF-7 cell and reverse drug resistance.Methods Molecular cloning technique was applied to construct the expression vector of siRNA against survivin,and effectene transfection reagent was used to transfect MCF-7 cell.Survivin expression was detected by qPCR and Western blot methods.The effects of paclitaxel or epirubicin combined with or without siRNA against survivin,on the drug susceptibility of MCF-7 cell were detected by CCK-8 assay and that of including MCF-7 cell apoptosis were detected by flow cytometry.Results Survivin-siRNA-2 effectively inhibited the expression of survivin mRNA (0.30±0.03) and protein (0.37±0.09) (P ＜ 0.05).Both paclitaxel [IR 24,48 h =(38.5±4.0) ％,(41.7±6.3) ％] and epirubicin [IR 24,48 h =(37.0±8.6) ％,(40.6± 12.1) ％] can suppress the proliferation of MCF-7 cell and induce its apoptosis,and siRNA against survivin combined with chemotherapy drugs enhanced both effects significantly[paclitaxel IR 24,48 h =(76.0±2.9) ％,(85.1±4.0) ％; epirubicin IR 24,48 h =(74.6±5.6) ％,(82.5±4.8) ％] (P ＜ 0.05).The inhibition rate of MCF-7 was concentration and time dependent.Conclusions Blocking survivin gene expression by RNAi,and combining with the appropriate chemotherapy can significantly enhance the sensitivity of MCF-7 cell to drugs and cell apoptosis.This technology has important potential clinical value in the therapy of breast cancer.

To find out which biomaterial had the best biocompatibility, we compared the acute phase reaction of common biomaterials preparing for vascular grafts with the material of polyurethane modified by silk fibroin (SF-PU(1:1)). After transplanted the materials of dacron, polyterafluoroethylene (e-PTFE), polyurethane (PU), SF-PU(1:1) in rat muscle for one week, we studied the influence of different biomaterials on the histocompatibility by using rat acute toxicity test, test of local reaction in muscle, tissue section staining, WBC and PLT count. As a result, dacron had the worst histocompatibility. The other biomaterials had slight local inflammatory reaction. The WBC and PLT was nearly the same with the blank except dacron. e-PTFE, pure PU and SF-PU(1:1) had the better histocompatibility than traditional dacron. Especially SF-PU(1:1) had the best histocompatibility. Because of the better physical properties and histocompatibility of SF-PU( 1:1), the prospect of preparing small-diameter vascular grafts with SF-PU was cheerful.
Acute-Phase Reaction ; Animals ; Biocompatible Materials ; Blood Vessel Prosthesis ; Blood Vessel Prosthesis Implantation ; instrumentation ; Female ; Fibroins ; chemistry ; Implants, Experimental ; Macromolecular Substances ; chemistry ; Male ; Materials Testing ; methods ; Muscle, Skeletal ; physiology ; Polyurethanes ; chemistry ; Prosthesis Design ; Random Allocation ; Rats ; Rats, Sprague-Dawley