Effect of exogenous Apoptin over-expression on apoptosis of orthotopic transplantation tumor of human breast cagcer cell line MCF-7 and the mechanism

Objective By constructing recombinant expression plasmid pLLYP3 expressing recombinant Apoptin (VP3) gene,to discuss the effect of VP3 inducing tumor cells into apoptosis on human breast cancer cell MCF-7 orthotopic transplantation tumors and the mechanism.Methods VP3 gene was cloned into the plasmid pLP-LNCX to form the recombinant plasmid pLLVP3,and MCF-7 orthotopic transplantation tumor model Was established,then pLLVP3 was infected into models.The expression of VP3 gene was detected by Western blot.TdT-mediated duTp nick end labeling (TUNEL) assay was used to verify apoptosis of tnnlor cells.At last Caspase-3 and B cell lymphoma-2 (bcl-2) were detected by Western blot.Results Sequence analysis revealed the recombination of plasmid pLLVP3,and 1×10~7 pfu/ml virus was obtained.The findings of animal experiment showed that tulnor inhibition rate of pLVP3 with low and high doses was 65.52% and 68.23% respectively,evidently higher than that in control group(t=4.06,P<0.01).Besides,Apoptin protein Was over-expressed.Forty-eight h after infection,TUNEL analysis showed obvious apoptosis peaks with the highest percentage rate of apoptotic cells present and cellular Caspase-3 expression could be detected in pLLVP3-infected group.Conclusion VP3 gene could induce apoptosis in human colon cancer cell line MCF-7 in vivo by activating Caspase-3 expression. Key words: Breast carcinoma; Gene;  Retmvims; Apoptosis