b overexpression accelerates tumorigenesis in A549 xenografts. A: Western blot shows total endogenous VEGF expression in PC-3 and A549 cells, and VEGF121/165b-overexpression in the transfected cell pools. Two different exposure times were used to develop the blots: Long time (for endogenous VEGF protein levels in PC-3 and A549 cells) and short time (for transfected cells) exposure. Bands corresponding to glycosylated and non-glycosylated proteins can be observed. B: PC3 cells engineered to overexpress VEGF121b, VEGF165b, or both, injected subcutaneously into athymic mice. No statistical differences between groups are found, but tumors originated from injection of VEGF121b-overexpressing cells tend to be larger than those observed for the other groups. C: Tumors resulting from injection of A549 cells overexpressing VEGF121/165b isoforms are significantly larger (p < 0.01) than controls.