Hypoxia-inducible factor 1-alpha translation pathway (HIF-1α/mTOR axis)

The Hypoxia-inducible factor 1-alpha (HIF-1α) translation pathway via 4E-BP1 and S6K/p70S6K is a critical signaling axis that regulates the protein synthesis of HIF-1α in response to growth factors and nutrient availability (PubMed: 11290332). While HIF-1α levels are primarily controlled by oxygen-dependent degradation via the VHL E3 ubiquitin ligase, its translation is modulated by the Mechanistic target of rapamycin complex 1 (mTORC1) (UniProt: P42345). mTORC1 phosphorylates Eukaryotic translation initiation factor 4E-binding protein 1 (4E-BP1), which releases eIF4E to form the eIF4F complex, and activates Ribosomal protein S6 kinase beta-1 (p70S6K), both of which promote the translation of HIF-1α mRNA (PubMed: 17611777). This pathway is frequently hyperactivated in various malignancies, such as renal cell carcinoma and breast cancer, leading to elevated HIF-1α protein levels even under normoxic conditions, a phenomenon that drives angiogenesis and metabolic adaptation (PubMed: 12947120). Therapeutic targeting of this axis is primarily achieved through mTOR inhibitors like Everolimus and Temsirolimus, which suppress HIF-1α translation and inhibit tumor progression (PubMed: 15265933). Clinical monitoring of this pathway often utilizes biomarkers such as the phosphorylation status of S6K1 or 4E-BP1 to confirm target engagement and therapeutic efficacy.

Other names

mTORC1-HIF1α axisPI3K/Akt/mTOR/HIF-1α signaling pathwaymTOR-mediated HIF-1α translationmTORC1/4E-BP1/S6K1/HIF-1α axis

Inhibition of mTORC1 kinase activity, which prevents the phosphorylation of 4E-BP1 and S6K1, thereby suppressing the translation of HIF-1α mRNA and reducing its protein levels (PubMed: 11290332, 17611777).