Objective   To construct an recombinant adenovirus vector of vascular endothelial growth factor small interfering RNA(Ad5-VEGFsi) and to observe its inhibitory effect on the cell proliferation of human leukemia K562 cells.     Methods   The specific human VEGF siRNA was subcloned into the shuttle plasmid pSES-HUS and then cotransfected with plasmid pAdeasy-1 to produce pAd5-VEGFsi by ho

mologous recombination. The identified recombinant plasmid pAd5-VEGFsi was packaged and amplified in 293 cells. At 72 h after the transfection of Ad5-VEGFsi into K562 cells

VEGF mRNA expression and the protein level of VEGF in the cell culture supernatant were determined by RT-PCR and ELISA

respectively. Cell proliferation was measured by MTT assay and cell apoptosis by flow cytometry.     Results   The recombinant adenovirus Ad5-VEGFsi was successfully constructed. Ad5-VEGFsi with the titer of 4.6×10

11

pfu/ml was harvested by CsCl gradient purification. Compared with those in the control

EGF mRNA in cells decreased by 66.55％ (P0.01) but the VEGF protein concentration in the cell culture supernatant reduced by 86.03％(P0.01). As a consequence

the cell growth was inhibited

but the cell apoptosis rate increased 13.89% as compared with those in the control (P0.01).     Conclusion   Recombinant adenovirus Ad5-VEGFsi could effectively down-regulate VEGF expression in K562 cells

inhibit cell growth

and induce cell apoptosis.