Hypoxia-Inducible Factors in Tumor Biology

Hypoxia‐inducible factors (HIFs) are master transcriptional regulators that enable tumour cells to adapt to low oxygen tensions. In well‐oxygenated cells, prolyl hydroxylases modify HIF‐α subunits, targeting them for ubiquitin–proteasome‐mediated degradation via the von Hippel–Lindau (VHL) tumour suppressor. Under hypoxic conditions, HIF‐α escapes hydroxylation, accumulates in the nucleus, dimerises with HIF‐β and drives expression of genes governing angiogenesis, metabolic reprogramming, cell survival and invasion. This adaptive response remodels the tumour microenvironment by promoting vascular endothelial growth factor (VEGF) production, enhancing glycolytic flux and altering extracellular matrix composition. HIF‐driven pathways confer resistance to chemotherapy, radiotherapy and immune surveillance, and shape interactions between cancer cells, stromal fibroblasts and infiltrating immune cells. Genetic alterations affecting VHL, prolyl hydroxylase domain enzymes and components of the ubiquitin–proteasome system further dysregulate HIF activity in diverse malignancies. Advances in the structural and functional characterisation of HIF complexes have opened avenues for selective inhibition, with emerging small molecules targeting HIF‐α stability, DNA binding or co-activator recruitment. The global significance of HIF biology extends beyond oncology to ischaemic disease, underlining the translational promise of strategies that modulate oxygen‐sensing pathways.

Research from Nature Portfolio

Recent studies have employed saturation genome editing to map thousands of single‐nucleotide variants across the VHL coding sequence, precisely quantifying how each variant alters protein function and predisposes to clear cell renal cell carcinoma. By measuring mRNA dosage effects in isogenic cell lines, researchers defined core pathogenic alleles, elucidating novel mechanisms of VHL dysfunction and refining risk stratification across tumour types. This work demonstrates the power of systematic functional assays to resolve genotype–phenotype relationships in oxygen‐sensing pathways and informs clinical classification of VHL variants encountered in patients.

Hypoxia-Inducible Factors in Tumor Biology publication trend

The graph below shows the total number of articles in hypoxia-inducible factors in tumor biology across all publications each year (not limited to Nature Index journals).

Technical terms

Hypoxia‐Inducible Factor (HIF): A heterodimeric transcription factor comprising oxygen-sensitive α and constitutive β subunits that regulates genes enabling cell survival under low oxygen.

Von Hippel–Lindau (VHL) Tumour Suppressor: An E3 ubiquitin ligase that recognises hydroxylated HIF-α and targets it for proteasomal degradation under normoxia.

Prolyl Hydroxylase Domain (PHD) Enzymes: Oxygen‐dependent enzymes that hydroxylate HIF-α proline residues, marking the protein for VHL-mediated ubiquitination.

Ubiquitin–Proteasome System: A cellular pathway in which proteins tagged with ubiquitin are degraded by the proteasome, controlling protein turnover and regulatory signalling.

Tumour Microenvironment (TME): The complex milieu of cancer cells, stromal cells, immune cells, extracellular matrix and signalling molecules that influences tumour growth and therapy response.

References

1. Hypoxic microenvironment in cancer: molecular mechanisms and therapeutic interventions. Signal Transduction and Targeted Therapy (2023).
2. Saturation genome editing maps the functional spectrum of pathogenic VHL alleles. Nature Genetics (2024).
3. Role of hypoxia in cancer therapy by regulating the tumor microenvironment. Molecular Cancer (2019).
4. Hypoxia-inducible Factor 1 (HIF-1) Promotes Extracellular Matrix Remodeling under Hypoxic Conditions by Inducing P4HA1, P4HA2, and PLOD2 Expression in Fibroblasts*. Journal of Biological Chemistry (2013).