PlGF-mediated ET-BR expression involves PI-3kinase, ROS and HIF-1α. THP-1 monocytes were treated with PlGF for 24 hours in the absence and presence of inhibitors (A) and after transfection with siRNA constructs (B) and transfection with HIF expression plasmids (B). (A,B) RNase protection assay. (C) Schematics of ET-BR promoter showing the locations and sequence of HIF-1α binding sites and corresponding mutations as shown by asterisk. (D) PlGF-mediated ET-BR promoter luciferase activity of full-length and deletion constructs. (E) THP-1 cells were transfected with − 392/+493 ET-BR luciferase promoter construct, followed by treatment with PlGF in the absence and presence of LY294002 (15 μM) or DPI (10 μM). (F) PlGF-mediated − 392/+493 ET-BR luciferase promoter activity in THP-1 cells transfected with proximal HIF-1α binding site mutant (HIF-1α-MI) and distal HIF-1α binding site mutant (HIF-1α-M2) as shown in panel C. Data in panels D through F are expressed as means (± SE) of 3 independent experiments. ***P < .001; **P < .01; ns, P > .05. Where indicated, the vertical lines show the repositioned gel lanes.