Effects of combination gene therapy system pcDNA3.1(-)-shVEGF/yCDglyTK on proliferation of gastric cancer cells

The U6-shRNA expression cassette of pGenesil-1-hVEGF4-shRNA was subcloned into the skeleton vector, fusion suicide gene pCDNA3.1(-)-CV-yCDglyTK synthesized in preliminary studies to establish the combination gene therapy system pCDNA3.1(-)-shVEGF/yCDglyTK, so as to investigate the effects of the combination gene therapy system on proliferation and apoptosis of gastric cells. MTT assay showed that cell growth in the pcDNA3.1(-)-CV-yCDglyTK and pcDNA3.1(-)-shVEGF/yCDglyTK groups was significantly inhibited. Compared with cells transfected with pcDNA3.1(-)-CV-yCDglyTK, cells transfected with pcDNA3.1(-)-shVEGF/yCDglyTK were more sensitive to 5-fluorocytosine (5-FC) (P < 0.05). Flow cytometry indicated that the apoptotic rate of SGC7901 cells in the pcDNA3.1(-)-shVEGF/yCDglyTK group was as high as (67.9 ± 4.78)%, which was significantly higher than the other four groups (P < 0.05). The combination gene therapy system pcDNA3.1(-)-shVEGF/yCDglyTK can effectively suppress SGC7901 cell proliferation and induce apoptosis of these gastric cancer cells, the effects of which is higher than simple RNA interference (RNAi) or suicide gene therapy.   Key words: Suicide gene, RNA interference, vascular endothelial growth factor, gastric cancer, calcium phosphate nanoparticle.