Figure 4

Triptolide decreased the transcription activity of HIF-1α protein. A. SKOV-3 cells were cultured under normoxic or hypoxic conditions in the presence or absence of triptolide for 12 h. The mRNA levels of VEGF, BNIP3 and CAIX were analyzed by real-time PCR and normalized with β-actin mRNA expression. B. ELISA assays were done for VEGF secretion from the SKOV-3 cells treated as in A. C. Triptolide inhibited new microvessel outgrowth arising from rat aorta rings. The representative images were from three separate experiments with similar results. D. MCF-7 cells were transiently transfected with the HRE-luciferase and renilla-luciferase reporter plasmids and then cultured at normoxia or hypoxia in the presence or absence of triptolide for 12 h followed by assays for luciferase activity. Data shown in A, B and D were expressed as mean ± SD, n = 3. The significant difference between triptolide-treated groups and hypoxia-control groups was analyzed by Student t test. * P < 0.05.