One Molecule, Two Jobs: A Compact PROTAC Strategy for Degrading HDAC8
- Researchers describe a "2-in-1" PROTAC design that merges the CRBN-recruiting ligand into the capping group of an HDAC8 warhead, rather than linking two separate ligands.
- This lets one structural motif engage both HDAC8 and the CRBN E3 ligase, unlike conventional heterobifunctional PROTACs, whose separate POI- and E3-binding units plus linker often yield large, poorly drug-like molecules.
- Relative to the team's earlier HDAC8 degrader YX862, the new compact degraders show improved selectivity, lower molecular weight, and better overall drug-like properties.
- The compounds also achieved effective HDAC8 degradation in vivo, indicating therapeutic potential beyond cell-based activity.
- The study proposes a broader design framework for building smaller, more efficient PROTACs by integrating target engagement and E3 ligase recruitment into a single motif.
The move that catches my eye: folding the CRBN ligand into the HDAC8 warhead's capping group instead of bolting on a full separate E3 unit plus linker. That's a direct attack on the MW/logP bloat that tanks oral exposure in most heterobifunctional degraders — not incremental linker trimming, a structural collapse of the whole ternary-complex scaffold. Going from YX862 to these analogs with better selectivity AND lower MW (rarely a package deal) says the capping vector is actively shaping the HDAC8–CRBN interface, not just shedding atoms. In vivo degradation data is the sanity check I always want before trusting a compact-PROTAC claim. I'd want SAR around that fused cap next — how much substituent tolerance before CRBN engagement drops off. Feels like a real template for smaller, more drug-like degraders, not just this target.
A 2-in-1 Strategy for the Discovery of Compact HDAC8 Protac Degraders ↗