Figure 3.

HIF-1α suppresses the gene expression of HIF-2α. (a) U87MG, U138MG and U343MG cells were transfected with non-specific siRNA (Control) or siRNA against HIF-1α (HIF-1α kd). Forty-eight hours after transfection, cells were incubated for 2 h in hypoxia (3% O₂). HIF-1α was detected by immunoblotting. β-Actin was used as loading control. The results are representative for three independent experiments. (b) U87MG, U138MG and U343 cells were transfected with water (WT), non-specific siRNA (neg.Control) or siRNA against HIF-1α (HIF-1α kd). Forty-eight hours after transfection, total mRNA was analyzed for HIF-2α and ribosomal protein L28 expression by qRT-PCR. Normalized HIF-2α/L28 ratios are shown. The data are shown as the mean±S.E.M. (n=3). *P<0.05, **P<0.01