Double suicide genes driven by kinase domain insert containing receptor promoter selectively kill human lung cancer cells

BACKGROUND To investigate the selective killing efficacy of the double suicide genes driven by KDR promoter. MATERIALS AND METHODS A double suicide gene system with the KDR promoter, pcDNA3-KDRp-CDglyTK, was constructed and transfected into lung cancer cell lines L9981 and NL9980, and human hepatocellular carcinoma cell line HepG2. The efficiency and specificity of the double suicide gene system were assayed by in vitro cellular proliferation and apoptosis, as well as in vivo xenograft studies. RESULTS The transgenic CD and TK genes were only expressed in L9981 and NL9980 but not in HepG2 cells. Pre-treating transfected cells with 5-Fc and GCV significantly reduced proliferation, enhanced apoptosis in L9981 and NL9980 but not in HepG2 cells. The tumor formed by L9981 and NL9980 cells with the double suicide gene system was much smaller in vivo. CONCLUSION Tumor targeted expression of CDglyTK gene driven by KDR promotor represents a novel strategy for effective gene therapy of tumor with intrinsic KDR.