Fig. 2.

GPx1 is a HIF-1α target gene. (A, B, and C) Protein levels of GPx1, HIF‐1α, and HIF‐2α in GBM8401 and GBM04T cells with or without HIF‐1α or HIF‐2α knockdown at 24 h after hypoxic treatment (<1% O₂). (D and E) Protein levels of GPx1 and HIF-1α in U251 and GBM09T cells transfected with the control (CVT) or HIF-1α-ODD deletion mutant plasmids (HIF1-OD) for 48 h. (F) Luciferase reporter activities of GPx1 promoter in GBM8401 and GBM04T cells with or without HIF‐1α (LW6) or HIF‐2α (PT2399) inhibitor at 24 h after hypoxic treatment (<1% O₂). (G) Luciferase reporter activities of GPx1 promoter in U251 and GBM09T cells co-transfected with HIF1-OD for 48 h. (H) One putative hypoxia response element (HRE) was identified in the human GPx1 promoter. (I) Luciferase activities of GBM8401, U251, GBM04T, and GBM09T cells that carry Renilla luciferase reporter plasmids cotransfected with the WT or mutant GPx1 promoter regions; the cells were treated with or without hypoxia (<1% O₂) for 24 h. (J and K) ChIP followed by real‐time PCR (ChIP‐qPCR) assay of HIF‐1α binding in GPx1 promoter in response to hypoxia (<1% O₂) for 24 h; results are expressed as percentages of inputs. Error bars, SD within triplicate experiments. **p < 0.01; ***p < 0.001; ****p < 0.0001, compared with control (normoxia), CVT, or IgG. ^##p < 0.01; ^###p < 0.001; ^####p < 0.0001, compared with hypoxia plus scramble (Scr.) shRNA groups or hypoxia plus vehicle groups.