Targeted expression of TNF a in ECV304 cells

Results presented in this paper show that TNF a had been specifically expressed in vascular endothelial cells under the control of KDR p in pLXSN whose promoter and enhancer were deleted. Plasmids pLXSN-TNF a and pLXSN d-KDR p-TNF a were constructed and transfected into package cell line PA317 using Lipofectin AMINE method. The supernatant containing the virus was detected with NIH3T3 and was used to transfect NIH3T3 and ECV304 cells. After selection by G418, G418 resistant cell clones were cultured. ELISA analysis of the supernatant collected from tranfected clones showed that TNF-a expression level in ECV304 under the control of KDR p was 8 fold higher than that in NIH3T3, but TNF a expression level under the retroviral promoter had no difference between NIH3T3 and ECV304. The results strongly suggested that TNF a gene in the plasmid pLXSN d-KDR p-TNF a was specifically expressed in ECV304 cells under the control of KDR p. Therefore, this study illustrated the superiority of using targeted expression vectors in cancer gene therapy .