The Research Of Silencing The Expression Of Livin Gene To Enhance The Drug Sensitivity Of Prostate Cancer Cells To Sunitinib Malate

Objective:Prostate cancer is the serious death threat to males. It shows an increasing trend in China in recent years.The etiology of prostate cancer is not yet clear.It may be associated with genetics,sex hormones,ethnicity,food,environmental and other factors. Present study found that some gene with special features play an important role in prostate cancer's invasion,progression and metastasis.Livin, a novel member of the human inhibitors of apoptosis protein (IAP) family, plays an important role in tumor progression and occurrence by inhibiting cell apoptosis. High levels of Livin expression contribute to tumor progression, a poor prognosis and correlate with more aggressive behaviors, such as decreased the response to chemotherapeutic agents and shortened survival time. Sunitinib malate as an oral small molecule multi-target tyrosine kinase receptor inhibitor suspends the supply of blood to the tumor cell angiogenesis and directly attacks on tumor cells. It provide an important therapeutic strategy in castration resistant prostate cancer for the dual depression effect with VEGF and PDGF. RNAi is a phenomenon that refers to provocate by highly conserved double-stranded RNA and specifically degrade in homologous mRNA. It is one of the ways in gene post-transcriptional silence. We use RNAi to silence Livin gene in prostate cancer cells and observe the influence in the survival of prostate cancer with no Livin gene and Sunitinib malate's drug sensitivity.Methods:1.According to Livin mRNA sequence designs the interference target sequence and builds Livin eukaryotic expression vector.2.Using liposome transfects pSIREN-RetroQ-Livin interfering plasmid to PC-3 cells.Transfected with empty vector as control.Using Western blot detects protein expression before and after transfection.Using MTT assay reflects the changes of cell survival before and after transfection.3.Using MTT assay detects the survival situation of PC-3 cells when Sunitinib malate acts on PC-3 cells alone.Using MTT assay detects the changes of survival in PC-3 cells when Sunitinib malate acts on PC-3 cells along with transfection of Livin interfering plasmid.Calculate the IC50 of Sunitinib malate.Results:1.By restriction enzyme digestion and DNA sequencing it shows that pSIREN-RetroQ-Livin interfering plasmid has been successfully constru-cted.2.The results of Western blot shows that Livin expresses in PC-3 cells.The transfection of pSIREN-RetroQ-Livin interfering plasmid effect tively inhibits the expression of Livin in PC-3 cells. The results of-MTT assay shows that the proliferation was inhibited in PC-3 cells when pSIREN-RetroQ-Livin interfering plasmid were transfected.3.The results of MTT assay shows that the survival decreases in PC-3 cells when Sunitinib malate was joined.The survival decreases significantly when Sunitinib malate and interference plasmid act on PC-3 cells together comparing with Sunitinib malate alone and empty vector group.By using MTT assay and calculating IC50 it shows that the half inhibition rate of Sunitinib malate decreases significantly when interference plasmid was transfected comparing with other group.Conclusions:Silencing the expression of Livin gene could inhibit the proliferation of prostate cancer cells and enhance the drug sensitivity to Sunitinib malate.