OBJECTIVETo evaluate the specific killing effects of combination of recombinant adenovirus mediated double suicide gene driven by KDR promoter and survivin antisense oligonucleotide(ASODN) on colorectal cancer cells and vascular endothelial cells.

METHODSThe 293 packaging cells were transfected with the plasmids of pAdEasy-CDglyTK and the recombinant adenovirus were generated. The KDR expressive cells of SW620, ECV304 were infected with adenovirus, meanwhile survivinASODN was transferred into the same cells. The infection rate of adenovirus and transfection efficiency of survivinASODN were observed and the expression of CDglyTK was detected by RT-PCR. The expression of survivin was measured by Western blot. The killing effects and bystander effects on SW620, ECV304 were examined through MTT method.

RESULTSThe cells which were infected with the adenovirus mediated double suicide gene could be transfected with the survivin ASODN and the infection rate was not affected as well as the transfection efficiency. The high expression of CDglyTK gene was found in SW620, ECV304 cells infected with recombinant adenovirus and survivin ASODN decreased the survivin protein level. The survival rate of gene therapy group was significantly lower than that of negative group. The combination of survivin ASODN and AdKDR-CDglyTK gene therapy showed significantly lower survival rate of SW620 and ECV304 cells as compared with the AdKDR-CDglyTK or survivin ASODN used alone (P<0.05). The survival rate was slightly lower in GCV 100 microg/ml, 5-FC 2000 microg/ml than that AdKDR-CDglyTK used alone (P>0.05). The combined therapy of AdKDR-CDglyTK and survivin ASODN showed synergistic killing efficacy and more significant bystander effects.

CONCLUSIONThe combined gene therapy of AdKDR-CDglyTK system and survivin ASODN has stronger specific killing effects on colorectal cancer cells and vein endothelial cells.