Adenovirus-Mediated Gene Transfer of Herpes Simplex Virus Thymidine Kinase under the Control of KDR Promoter Confers the Sensitivity to Ganciclovir in Human Vascular Endothelial Cells

Objective: To investigate the specific killing effect of the adenoviral vector containing KDR promoter for the HSV-tk gene on the vascular endothelial cells. Methods: The human KDR promoter(-225 bp ～+127 bp) was cloned by PCR. Subsequently, a recombinant adenoviral plasmid carrying KDR promoter for the HSV-tk gene (pAdKDR-tk)was constructedwith the AdEasy system. As a control, the plasmid pAdCMV-tk carrying CMV promoter for the HSV-tk gene was also constructed. 293 packaging cells were transfected by both newly-constructed plasmids and the infectious viruses AdKDR-tk and AdCMV-tk were generated. Then the KDR-producing cells (HUVEC) and the KDR nonproducing cells (HepG2) were infected with AdKDR-tkand AdCMV-tk, followed by ganciclovir (GCV) administration. The living cells were collected and calculated in 5 days. Results: There was a markedly decrease in the percentage survival of HUVECcells infected with AdKDR-tk at a GCV concentration of 50 μg/ml when infected at a MOI of 100(31.49%±6 42%), while the percentage survival of HepG2 cells infected with AdKDR-tkwas 76.57%±3.49%. Transduction by AdCMV-tk showed GCV killing in both cell lines, and the percentage survival was 22.24%±3.77%(HUVEC)and 26.53%±6 84%(HepG2), respectively. Conclusion: Cell-specific killing was achieved by adenoviral vector containing KDR promoter for the HSV-tk gene and GCV treatment.