Figure 2. Q6 downregulates hypoxia-induced HIF1A protein expression and HIF1A-mediated signal transduction. (A and C) HepG2 (left) and Bel-7402 (right) cells were exposed to hypoxia or normoxia and treated with Q6 (0 to 5 μM) for 6 h. (A) Protein levels of HIF1A, EPAS1, and VEGFA were detected by western blot analysis. ACTB was analyzed as the loading control. Data are representative of 3 independent experiments. (B) An HRE-dependent reporter assay was used to determine the effect of Q6 on HIF1A transcriptional activity. Five independent experiments were performed and the values were expressed as the mean ± SD **P < 0.01 and ***P < 0.001, compared with untreated controls in hypoxia. (C) Total RNA was extracted and VEGFA mRNA expression was analyzed by RT-PCR, using GAPDH as a control gene. Five independent experiments were performed and the values were expressed as the mean ± SD **P < 0.01, compared with untreated controls in hypoxia.