Table 4.
Experimental investigations on hypoxia-inducible factors (HIFs) in glioblastoma models and animal subjects with induced tumors with combined genetic and targeted/systematic therapy.
| Reference | Country (Year) | Study Design | Species | Cell Line(s) | Targeted HIF | Related Factor | Role of HIF and Related Factors | Gene Modification | Effect of Gene Modification | Targeted Therapy | Pharmacological Effects |
|---|---|---|---|---|---|---|---|---|---|---|---|
| Huang et al. [90] | China (2018) | Lab (IV) | CL | U87 | HIF1α | PI3K/Akt/mTOR | PI3K/Akt/mTOR/HIF1α pathway is involved in enhancing the migration and invasion of human glioblastoma U87 cells under hypoxia. | TF | The enhancements of the migration and invasion of U87 cells under hypoxia could be suppressed by the mTOR pathway siRNA by targeting HIF1α. | 2-ME, LY294002, rapamycin, and p70S6K siRNA | 2-ME is an HIF1α inhibitor that reduces the migration and invasion of glioblastoma cells. The inhibitors of PI3K/Akt/mTOR, LY294002, and rapamycin, reduced the migration, invasion, and HIF1α protein expression. p70S6K siRNA suppressed the migration, invasion, and HIF1α expression under hypoxia. |
| Chhipa et al. [91] | USA (2018) | Lab (C) | Mice and CL | U87, A172, T98G, and HEK 293T | HIF1α | AMPK (AMPK/CREB1 axis) | By phosphorylating CREB1, AMPK enhances HIF1α and GABPA transcription to support glioblastoma bioenergetics. | KD and KO | Silencing CREB1 decreases HIF1α activity, cell viability, and GSC bioenergetics, while the knockout of AMPKα1 enhances glycolysis and accelerates tumorigenesis. | Bafilomycin | AMPK inhibition reduces GSC viability and has antitumorigenic effects. |
| Pang et al. [92] | USA (2023) | Lab (C) | Mice and CL | 293T | HIF1α | LGMN | LGMN is specifically expressed in TAMs and regulated by HIF1α | KD and KO | BMDMs from HIF1α-mKO mice exhibited aberrantly diminished Lgmn expression levels, while Lgmn-mKD mice displayed a marked extension in survival compared to control mice. | Anti-PD1 | The blockade of the HIF1α-LGMN axis synergizes with anti-PD1 therapy in glioblastoma. |
| Hu et al. [93] | USA (2012) | Lab (C) | Mice and CL | U87, T98G, U251, U138, A172, G55, SF8244, SF8557, and U373 | HIF1α | HIF1α/AMPK | HIF1α and AMPK control hypoxia-induced LC3 changes, while BNIP3 expression depends solely on HIF1α, and p62 degradation occurs independently of both. | KO and TF | The knockdown of the essential autophagy gene ATG7 promotes bevacizumab responsiveness. | BEV and chloroquine | BEV treatment increased BNIP3 expression and hypoxia-driven growth in glioblastoma xenografts, reversed by chloroquine, an autophagy inhibitor. |
| Chou et al. [94] | Taiwan (2012) | Lab (C) | Mice and CL | U87, glioblastoma 8401, and U251 | HIF1α | ABCB1 | Cycling hypoxic stress increases chemoresistance via HIF–1-mediated ABCB1 induction. | KD | When the induction of ABCB1 was inhibited by siRNA, the chemotherapy resistance induced by cycling hypoxic stress decreased. | YC-1 | YC-1 combined with BCNU chemotherapy decreased ABCB1 induction and made therapy more effective. |
| Barliya et al. [95] | Israel (2011) | Lab (IV) | CL | ARPE-19, U87, and RCC-C2VHL−/− | HIF1α | hsp90 | Hsp90 mediates the pathways vital for angiogenesis, cell migration, and invasion. | TF | Hypericin interferes with VEGF promoter activation in tumor cell lines. | Hypericin | The hypericin-induced degradation of hsp90 client proteins compromises the pathways involved in angiogenesis, cell migration, and invasion. |
| Hsieh et al. [96] | Taiwan (2011) | Lab (C) | Mice and CL | glioblastoma 8401 and U87 | HIF-1 | NADPH oxidase subunit 4-mediated reactive oxygen species | Cycling hypoxic stress significantly increases ROS production, HIF-1 activation, and tumor growth. Nox4 is a critical mediator of these processes. | KD | Blocking ROS production through Nox4 shRNA inhibits tumor growth induced by cycling hypoxia or the tumor microenvironment. | Tempol | Tempol treatment inhibits tumor growth induced by cycling hypoxia or the tumor microenvironment. |
| Kannappan et al. [97] | United Kingdom (2022) | Lab (C) | Mice and CL | U87MG, U251MG, and U373MG | HIF1α and HIF2α | NF-kB | NF-kB, HIF1α, and HIF2α induce the expression of key EMT- and metastasis-related genes and promote glioblastoma cell migration and invasion. | TF | The expression of HIF2α mRNA was upregulated by HIF1α transfection but not vice versa. | Disulfiram | Disulfiram inhibits NF-kB activity and targets hypoxia-induced GSCs. It shows selective toxicity to glioblastoma cells, eradicates GSCs, and blocks migration and invasion. |
| Joseph et al. [98] | The Netherlands (2015) | Lab (IV) | CL | U87, SNB75, and U251 | HIF1α and HIF2α | ZEB1 (HIF1α-ZEB1 axis) | HIF1α–ZEB1 signaling axis promotes hypoxia-induced mesenchymal shift and invasion in glioblastoma in a cell line-dependent fashion. | KD | The ShRNA-mediated knockdown of HIF1α, and not HIF2α, prevented hypoxia-induced mesenchymal transition. | Digoxin | Digoxin inhibits HIF1α mRNA translation. |
| Caragher et al. [99] | USA (2019) | Lab (C) | Mice and CL | U251, glioblastoma 43, glioblastoma 12, glioblastoma 5, glioblastoma 6, and glioblastoma 39 | HIF1α and HIF2α | DRD2 | The activation of DRD2 triggers the expression of HIF proteins and enhances the capacity for sphere formation, which serves as an indicator of the GIC state and tumorigenicity. | KD | The SH-RNA-mediated knockdown of DRD2 showed a significant reduction in sphere-forming capacity. | Chlorpromazine | The inhibition of glioblastoma growth by blocking the dopamine signaling pathway. |
| Peng et al. [100] | China (2021) | Lab (C) | Mice and CL | U251 | HIF1α | PDGFD-PDGFRα | Under normoxic or mild-hypoxic conditions, HIF1α binds to the PDGFD proximal promoter and PDGFRA intron enhancers in glioblastoma cells, leading to the induction of their expression. | KD and KO | PDFGRA knockdown extends the survival of xenograft mice, inhibits cell growth and invasion in vitro, and eradicates tumor growth in vivo. | Echinomycin | Echinomycin induces glioblastoma cell apoptosis and effectively inhibits the growth of glioblastoma in vivo by simultaneously targeting the HIF1α-PDGFD/PDGFRα-AKT feedforward pathway. |
| Han et al. [101] | China (2015) | Lab (C) | Mice and CL | U87 and U251 | HIF1α | NF-κB/RelA-PKM2 | NF-κB/RelA is involved in proliferation, anti-apoptosis, angiogenesis, and metastasis, promoting aerobic glycolysis via the transcriptional activation of PKM2. | TF | NF-κB/RelA promotes glioblastoma cell glycolysis depending on PKM2. | Fenofibrate | FF inhibits glioblastoma glycolysis in a dose-related manner depending on PPARα activation. It inhibits the transcriptional activity of NF-κB/RelA and disrupts its association with HIF1α. |
| Dominguez et al. [102] | USA (2013) | Lab (C) | Mice and CL | U251, U87, A375, MDA-MB-231, HeLa, and human fibroblast cell lines | HIF1α | DGKα | DGKα and its product, phosphatidic acid, are associated with multiple oncogenic pathways such as mTOR, HIF1α, and Akt. | KD | In cancer cells, the inhibition of DGKα results in cell toxicity through caspase-mediated apoptosis. The reduced expression of mTOR and HIF1α significantly contributes to the cytotoxic effects observed upon DGKα knockdown and inhibition in cancer. | R50922 and R59949 | Induced caspase-mediated apoptosis in glioblastoma cells and in other cancers, but lacked toxicity in non-cancerous cells. |
| Hsieh et al. [103] | Taiwan (2015) | Lab (C) | Mice and CL | U251, U87, and glioblastoma 8401 | HIF1α and HIF2α | Livin proteins | HIF1α regulates Livin transcription in hypoxia, promoting anti-apoptosis in glioblastoma and enhancing radioresistance and chemoresistance. | KD | The knockdown of Livin suppresses tumor hypoxia-induced TR and generates a synergistic suppression of antitumor growth and tumor cell death. | Cell-permeable peptide TAT-Lp15 | Livin blockage enhances the efficiency of radiation plus temozolomide treatment in glioblastoma xenografts. |
| Ahmed et al. [104] | UK (2018) | Lab (IV) | CL | U251, U87, and SNB219 | HIF1α and HIF2α | CD133 | CD133 is a cell surface marker used to identify glioblastoma cancer stem cells. | KD | HIF1α and HIF2α knockdown led to a reduced CD133 expression. CD133 knockdown increases the sensitivity of glioblastoma cells to cisplatin. | Cisplatin | The hypoxia-induced cisplatin sensitivity of glioblastoma cells may be HIF-independent and may be directly or indirectly induced via CD133 activation. |
| Lee et al. [105] | Korea (2017) | Lab (C) | Mice and CL | Biopsy | HIF1α | ERK1/2 and VEGF | ERK1/2 signaling and VEGF, a HIF1α downstream target, contribute to solid tumor pathogenesis. | TF | DT at clinically relevant concentrations reduces hypoxia-induced HIF1α protein accumulation and downstream signaling pathways. | Digitoxin | DT at clinically achievable concentration functions as an inhibitor of HIF1α. |
| Bar et al. [106] | USA (2010) | Lab (C) | Mice and CL | HSR-glioblastoma 1 and HSR-glioblastoma 2 | HIF1α | CD133 | HIF1α induces CD133 expression and enhances the stem-like tumor subpopulation in hypoxia. | TF | An elevated percentage of CD133 positive cells. | Digoxin | Digoxin suppressed HIF1α protein expression, HIF1α downstream targets, and slowed tumor growth. |
| Chen et al. [107] | China (2015) | Lab (C) | Mice and CL | U251, U87, and glioblastoma 8401 | HIF1α | NF-κB and Bc-xl | Cycling hypoxia mediates Bcl-xL expression via HIF1α or NF-κB activation, which results in chemoresistance. | KD | Bcl-xL knockdown inhibited cycling hypoxia-induced chemoresistance. | Tempol, YC-1, and Bay 11-7082 | The suppression of the cycling hypoxia-mediated Bcl-xL induction. |
| Li et al. [108] | India (2020) | Lab (C) | Mice and CL | U87 and U251 | HIF1α | IDH1-R132H | The overexpression of IDH1-R132H increased the expression of HIF1α and the downregulation of HIF1α suppressed the IDH1-R132H-induced effect on glioblastoma. | KD | The KD of FAT1 inhibited the IDH1-R132H-induced reduction in tumor growth in xenograft mice. | TMZ | The overexpression of IDH1-R132H led to reduced cell proliferation, increased apoptosis, decreased migration and invasion, enhanced TMZ-induced cytotoxicity, and diminished tumor growth in xenograft mice. |
| Ge et al. [109] | China (2018) | Lab (C) | Mice and CL | U87MG and HEK293T | HIF1α | miR-26a | HIF1α/miR-26a axis strengthens the acquisition of TMZ resistance through the prevention of Bax and Bad in mitochondria dysfunction in glioblastoma. | TF | HIF1α serves as a pivotal upstream regulator of miR-26a expression in glioma. | TMZ | miR-26a is an important regulator of TMZ resistance induced by hypoxia, which can effectively protect mitochondria function and reduce apoptosis by targeting bax and bad. |
| Liao et al. [110] | China (2022) | Lab (C) | Mice and CL | U251, U87, A172, GSC11, GSC20, GSC262, GSC267, GSC295, GSC28, GSC284, and GSC627 | HIF1α | PRMT3 | PRMT3 promotes glioblastoma progression by enhancing HIF1α-mediated glycolysis and metabolic rewiring. | KD | The reduced proliferation and migration of glioblastoma cell lines and patient-derived GSC in cell culture and inhibited tumor growth. | SGC707 | The targeting of PRMT3 decreases HIF1α expression and glycolytic rates in glioblastoma cells and inhibits glioblastoma growth. |
| Kioi et al. [111] | California (2010) | Lab (C) | Mice and CL | U251 and U87 | HIF1α | SDF-1/CXCR4 | BMDCs are recruited to tumors through the HIF-1-dependent interaction of SDF-1 and its receptor, CXCR4. | TD | AMD3100 enhanced the radiosensitivity. | AMD3100 | AMD3100 is an inhibitor of SDF-1/CXCR4 interactions, which blocks the vasculogenesis pathway. |
| Boso et al. [112] | Italy (2019) | Lab (IV) | CL | Biopsy | HIF1α | β-catenin/TCF1 | In hypoxic glioblastoma cells, the β-catenin/TCF1 complex recruits HIF1α to promote the transcription of genes associated with neuronal differentiation. | TF | Cells silenced for TCF1 experienced a complete inhibition of their neuronal differentiation potential. | TCF4E | TCF4E possesses inhibitory effects on gene transcription. |
CL—cell line; Lab—laboratory study; C—combined design (in vivo and in vitro); IV—in vitro; KD—knockdown; KO—knockout; TF—transfection; TD—transduction; siRNA—small interfering RNA; PDGFD—platelet-derived growth factor D; PDGFRα—platelet-derived growth factor receptor alpha; AMPK—AMP-activated Protein Kinase; CREB1—cAMP Response Element-Binding Protein 1; GABPA—GA Binding Protein transcription factor subunit Alpha; LGMN—Legumain; TAMs—Tumor-Associated Macrophages; mKO—Myeloid Cell-Specific knockout; BMDMs—Bone Marrow-Derived Macrophages; Nox4—NADPH Oxidase 4; ROS—reactive oxygen species; LC3—Microtubule-Associated Protein 1A/1B-Light Chain 3; BNIP3—Bcl2/adenovirus E1B 19kDa Interacting Protein 3; ATG7—Autophagy-Related 7; NF-kB—Nuclear Factor Kappa B; EMT—Epithelial–Mesenchymal Transition; GIC—glioma-initiating cells; DRD2—Dopamine Receptor D2; DGKα—Diacylglycerol Kinase Alpha; ERK1/2—Extracellular Signal-Regulated Kinase 1/2; VEGF—vascular endothelial growth factor; PKM2—Pyruvate Kinase M2; PKM2—Pyruvate Kinase M2; DGKα—Diacylglycerol Kinase Alpha; TR—Tumor Regrowth; CD133—Prominin-1; ZEB1—Zinc Finger E-Box Binding Homeobox 1; NF-κB—Nuclear Factor Kappa B; Bcl-xL—B-cell lymphoma-extra-large; IDH1—isocitrate dehydrogenase 1; FAT1—FAT Atypical Cadherin 1; TMZ—temozolomide; PRMT3—Protein Arginine Methyltransferase 3; SDF-1—stromal cell-derived factor 1; CXCR4—C-X-C Motif Chemokine Receptor 4; TCF1—transcription factor 1; TCF4E—transcription factor 4E; AMD3100—Plerixafor; GIC—glioma-initiating cell.