OBJECTIVE To evaluate the selectively killing effect of adenovirus(Ad)mediated double suicide gene driven by VEGF promoter on pancreatic cancer cell SW1990.
METHODS VEGFexpressing SW1990 were infected by Ad-VEGFP-CDTK and Ad-null.respectively.The infection rate was observed and the expression of CDTK was detected by RT-PCR and Western blotting.Followed by treatment with 5-FC and GCV killing effects were evaluated and bystander effects were analyzed by MTF.Pathological character of cells was observed by electron microscopy and distribution of cell cycle was detected by flow cytometry.The caspase-3 activity was detected by absorption spectrometry.
RESULTS The infection rate of the resultant recombinant Ad to SW1990 cells was not apparently different.RT-PCR and Western blotting demonstrated product of CDTK gene in SW1990 cell infected by Ad-VEGFP-CDTK.Prodrug could inhibit proliferation of SW1990 and the effect was dose-dependent.There was considerable bystander effect as observed by MTF.Apoptotic peak was also shown by flow cytometry.Morphologic features of apoptosis in SW1990 cells were displayed via electron microscopy.Cells at the G0-G1 phase was increasing and the rate at the G2-M and S phase was decreased by prodrug.The caspase-3 activity gradually rised with the increasing concentration of the prodrug.
CONCLUSIONS The CDTK fusion gene system controlled by VEGF promoter has killing effect on the VEGF-expressing SW1990 cells and inducing the cell apoptosis.