PROTACs in gastrointestinal cancers.

Proteolysis targeting chimera (PROTAC) presents a powerful strategy for targeted protein degradation (TPD). The heterobifunctional PROTAC molecule consists of an E3 ligase ligand covalently linked to a protein of interest (POI) via a linker. PROTAC can induce ubiquitinated proteasomal degradation of proteins by hijacking the ubiquitin-proteasome degradation system (UPS). This technique has the advantages of broad targeting profile, good cell permeability, tissue specificity, high selectivity, oral bioavailability, and controllability. To date, a growing number of PROTACs targeting gastrointestinal cancers have been successfully developed, and, in many cases, their POIs have been validated as clinical drug targets. To the best of our knowledge, 15 PROTACs against various targets are currently tested in clinical trials, and many more are likely to be added in the near future. Therefore, this paper details the mechanism, research progress, and application in clinical trials of PROTACs, and summarizes the research achievements related to PROTACs in gastrointestinal cancers. Finally, we discuss the advantages and potential challenges of PROTAC for cancer treatment.