Fig. 3

NOX4 positively regulates FOXM1 expression by mediating HIF-1α stabilization. A Western blot analysis showing HIF-1α protein levels in NOX4-overexpressing or NOX4-knockdown glioblastoma cells. B Western blot analysis showing HIF-1α protein levels in NOX4-knockdown glioblastoma cells. C qPCR detection of FOXM1 mRNA levels in HIF-1α-overexpressing glioblastoma cells. D Western blot analysis showing the FOXM1 protein levels in HIF-1α-overexpressing glioblastoma cells. E Western blot analysis showing the FOXM1 protein levels in normoxic and hypoxic glioblastoma cells. F The indicated glioblastoma cells were transfected with HIF-1α siRNA or negative control siRNA, and the protein levels of FOXM1, HIF-1α, and NOX4 were measured by Western blot. G Western blot analysis showing the protein levels of the FOXM1 downstream targets cyclin B1 and PLK1 in normoxic and hypoxic glioblastoma cells. H Map of the HIF-1α binding site sequence from the JASPAR database. I Sequences and positions of putative HIF-1α-binding regions on the FOXM1 promoter and luciferase reporter constructs for wild-type or mutant FOXM1 promoter were cotransfected into U87MG cells along with EV- or HIF-1α-overexpressing plasmids for 48 h. Promoter activity was examined with a dual-luciferase reporter assay kit. *, P < 0.05; **, P < 0.01; ***, P < 0.001