Structural Basis for the Allosteric Inhibition of Hypoxia-Inducible Factor 2 by Belzutifan

• DOI: 10.1124/molpharm.122.000525
• Publication Date: 2022-09-27T12:50:26Z
• Authors: Xintong Ren; Xiaotong Diao; Jingjing Zhuang; Dalei Wu
• Keywords: Hypoxia-Inducible Factors; Hypoxia-Inducible Factor 1; PAS domain; Basic helix-loop-helix

Hypoxia-inducible factor (HIF)-2<i>α</i> and its obligate heterodimerization partner aryl hydrocarbon receptor nuclear translocator (ARNT), are both members of the basic helix-loop-helix-PER-ARNT-SIM transcription family. Previous studies have identified HIF-2<i>α</i> as a key oncogenic driver in clear cell renal carcinoma (ccRCC), rendering it promising drug target for this type kidney cancer. Belzutifan is first inhibitor approved treating ccRCC other cancers associated with von Hippel-Lindau disease. However, detailed inhibitory mechanism belzutifan at molecular level still unclear. Here we obtained crystal structure HIF-2<i>α</i>–ARNT heterodimer complex 2.75 Å resolution. The shows that binds into PAS-B pocket HIF-2<i>α</i>, destabilizes dimerization ARNT through allosteric effects mainly mediated by residue M252 near dimer interface. We further explored using biochemical functional assays. time-resolved fluorescence energy transfer–based binding assay showed disrupts <i>K_i</i> value 23 nM. luciferase reporter indicated can efficiently inhibit transcriptional activity an IC₅₀ 17 Besides, real-time polymerase chain reaction illustrated reduce expression downstream genes 786-O cancer cells dose-dependent manner. Our work reveals which allosterically inhibits provides valuable information subsequent development targeting HIF-2<i>α</i>. <h3>SIGNIFICANCE STATEMENT</h3> (bHLH-PAS) family factors emerging group small-molecule targets. Belzutifan, originally developed Peloton Therapeutics, Food Drug Administration–approved directly to bHLH-PAS protein, hypoxia-inducible (HIF)-2α. Based on protein-drug structure, assays, profiling gene expression, study regulatory how HIF-2α's thus reducing their links tumor progression.