Figure 2

VEGF-A-induced sFlt-1 release requires VEGFR-2 and the PI3K pathway. (a) sFlt-1 release from HUVEC 24 hours after incubation with PlGF-1 (20 ng/ml), VEGF-A (20 ng/ml) and VEGF-E (20 ng/ml). (b) sFlt-1 release from HUVEC after incubation with SU1498 (10 μM), a VEGFR-2 tyrosine kinase inhibitor, prior to addition of VEGF-A (20 ng/ml) for 24 hours. (c) sFlt-1 release from HUVEC infected with an adenovirus encoding PTEN (PTEN (wt)) or control adenovirus (CMV) prior to stimulation with VEGF-A (20 ng/ml) for 24 hours. Western blot demonstrating decreased PTEN expression in HUVEC infected with Ad-PTEN(wt) compared with Ad-CMV control (insert). (d) sFlt-1 release from HUVEC after incubation with LY294002 (10 μM), a PI3K inhibitor, prior to addition of VEGF-A (20 ng/ml) for 24 hours. (e) LY294002 prevented the VEGF-A-induced flt-1 promoter activity in porcine aortic endothelial cells, assayed by luciferase reporter assay. Data are expressed as mean (± SEM) or representative of three or more independent experiments performed in triplicate. **P < 0.01 vs. control.