Hydrophobic Tag Protein Degraders: An Emerging Therapeutic Strategy for Cancer.

Hydrophobic tag degraders (HyTDs) are a promising strategy for achieving targeted protein degradation (TPD). HyTDs are composed of a hydrophobic moiety conjugated via a linker to a ligand that binds to the protein of interest (POI). Binding induces a surface-exposed hydrophobic patch that mimics a misfolded protein, triggering degradation through the cell's diverse quality-control networks, including the ubiquitin-proteasome system (UPS), ubiquitin-independent proteasome degradation (UbInPD), the autophagy-lysosome pathway (ALP), and the unfolded protein response (UPR). This distinct multi-pathway mechanism distinguishes HyTDs from traditional TPD strategies such as PROTACs and molecular glue degraders (MGDs), which rely on a narrow pool of specific E3 ligases. The effectiveness of HyTDs is influenced by the chemical properties of the hydrophobic moiety, the linker, and the ligand's binding kinetics to the POI. To date, several relevant cancer targets, including the androgen receptor (AR), AKT serine/threonine kinase 3 (Akt3), and enhancer of zeste homolog 2 (EZH2), have been successfully targeted using HyTDs. Gaining deeper mechanistic insight into the nature of HyT degradation will be essential to further the potential of HyTDs as powerful tools in cancer research and therapeutics.