Chemically induced cereblon (CRBN) degradation: efficacy of recruiting CRBN in comparison to VHL

As small molecule degrader technology has developed, it has raised the question of whether E3 ligases could be induced to self-ubiquitinate. To examine this question, we generated six CRBN-CRBN degraders (also referred to as homo-PROTACs) and six CRBN-VHL degraders (hetero-PROTACs). From these compounds we identified two potent and selective CRBN degraders (ZXH-4-130 and ZXH-4-137), both of which are CRBN-VHL compounds. Comparison of these compounds to previously reported small molecule CRBN degraders further validated our observation that CRBN-VHL compounds are more potent degraders of CRBN than CRBN-CRBN compounds.