Figure 4. HIFs regulate HIG2 expression, and HIG2 regulates HIF1α.

HIG2 was inhibited after HIF1α knockdown in both TSCCs and GSCs and also after HIF2α knockdown in TSCs A. Western blot showing HIG2 upregulation under hypoxia conditions and downregulation with HIF1α inhibition B. HIF1α knockdown also inhibited HIG2 upregulation induced by hypoxia mimics C. †P<0.05 compared to hypoxia mimics. HIF1α was downregulated after HIG2 knockdown in both TSCCs and GSCs D. Location of putative hypoxia response elements (HRE) in the −1190/+133 HIG2 gene promoter E. Putative HREs are represented by circled numbers and sequences are displayed. ChIP using HIF1α or HIF2α antibodies and the primer spanning the 1^st to 6^th HREs in the HIG2 promoter F. *P<0.05 compared to control group.