Targeted Histone Deacetylase Degradation via Chemical Induced Proximity by Direct Recruitment of the CUL4 Complex Adaptor Protein DDB1

Targeted protein degradation using proteolysis-targeting chimeras (PROTACs) has emerged as a powerful strategy for disease treatment. By recruiting E3 ligases, these molecules enable selective degradation of pathogenic proteins. Cereblon (CRBN), a key component of the CUL4-DDB1-CRBN E3 ligase complex, is the most commonly recruited E3 ligase in PROTACs, including those targeting histone deacetylases (HDACs). In this study, we designed SZ-2, a bifunctional molecule derived from the DDB1 ligand MM-02-57 and the HDAC inhibitor vorinostat, to simultaneously bind DDB1 and HDACs. SZ-2 effectively induced degradation of HDAC1 and HDAC2 and demonstrated potent anti-multiple myeloma activity, highlighting its potential as a novel therapeutic agent.