Figure 5.

Effects of PSH on the HIF-1α and VEGF expression levels in U251 cells under hypoxia. (A) Protein expression levels of HIF-1α and VEGF in U251 cells. (B) The HIF-1α transcriptional activity was measured by a luciferase reporter assay. The results are presented as the fold-change relative to the control group. (C) PSH inhibited the secretion of VEGF measured by ELISA. (D) PSH inhibited the 20S proteasome activity. Total lysates were isolated and the proteasome activity was measured using a fluorogenic assay kit. Experiments were repeated three times, and the data are presented as the mean ± SD. ##P<0.01 vs. control; ^**P<0.01 vs. hypoxia. PSH, Paris saponin H; HIF-1α, hypoxia-inducible factor-1α; VEGF, vascular endothelial growth factor.