Combinatorial Ubiquitination REal-time PROteolysis (CURE-PROs): A Modular Platform for Generating Reversible, Self-Assembling Bifunctional Targeted Degraders.

Proteolysis-Targeting Chimeras (PROTACs) are bifunctional molecules that bring a target protein and an E3 ubiquitin ligase into proximity to append ubiquitin, thus directing target degradation. Although numerous PROTACs have entered clinical trials, their development remains challenging, and their large size can produce poor drug-like properties. To overcome these limitations, we have modified our Coferon platform to generate Combinatorial Ubiquitination REal-time PROteolysis (CURE-PROs). CURE-PROs are small molecule degraders designed to self-assemble through reversible bio-orthogonal linkers to form covalent heterodimers. By modifying known ligands for Cereblon, MDM2, VHL, and BRD with complementary phenylboronic acid and diol/catechol linkers, we have successfully created CURE-PROs that direct degradation of BRD4 both in vitro and in vivo. The combinatorial nature of our platform significantly reduces synthesis time and effort to identify the optimal linker length and E3 ligase partner to each target and is readily amenable to screening for new targets.