RTEF-1 increases cell proliferation and accelerates tube formation. A, BrdUrd incorporation assay in RTEF-1 o/e HMEC-1 cells in normoxia and hypoxia. **, p < 0.01. B, images (panel a) and quantification (panel b) demonstrate the Matrigel assay of HMEC-1 transfected with RTEF-1 and RTEF-1 siRNA at 2 and 6 h under normoxic and hypoxic conditions. C, BrdUrd incorporation assay of HMEC-1/RTEF-1 cells treated with 50 μm YC-1 for 15 min prior to hypoxia. D, Matrigel assay of HMEC-1/RTEF-1 cells treated with 50 μm YC-1 under normoxic and hypoxic conditions. E, Western blot analysis of expression of HIF and VEGF proteins in HMEC cells in the presence or absence of YC-1. The results are from three independent experiments (means ± S.D.). *, p < 0.05; **, p < 0.01.