Cytotoxicity of VEGF
/rGel to PAE/VEGFR-2 cells does not result in apoptosis. A, Decreased VEGFR-2 and increased p-VEGFR-2 levels in PAE/VEGFR-2 cells and HUVECs treated with VEGF121/rGel at IC50 doses for 24 h. Actin levels were used as a loading control. NT, not treated. B, TUNEL analysis of PAE/VEGFR-2 cells treated with 1 nM VEGF121/rGel for 24, 48 and 72 hours. Positive control cells were incubated with 1 mg/ml DNAse for 10 minutes at 37°C. C, Lack of effect of VEGF121/rGel on apoptotic markers in endothelial cells. Protein levels of Bax, Bcl-XL and caspase-3 remained unchanged, suggesting that the mechanism of cell death induced by the construct is not apoptotic. Levels of cytochrome C, caspase-6, and Bcl-2 were undetectable (data not shown). NT, not treated. D, PAE/VEGFR-2 cells treated with VEGF121/rGel did not demonstrate PARP cleavage, while cells exposed to dexamethasone (positive control) showed cleaved PARP.