Iterative Design and Optimization of Initially Inactive Proteolysis Targeting Chimeras (PROTACs) Identify VZ185 as a Potent, Fast, and Selective von Hippel–Lindau (VHL) Based Dual Degrader Probe of BRD9 and BRD7

• Published in: Journal of medicinal chemistry Vol. 62; no. 2; pp. 699 - 726
• Main Authors: Zoppi, Vittoria, Hughes, Scott J, Maniaci, Chiara, Testa, Andrea, Gmaschitz, Teresa, Wieshofer, Corinna, Koegl, Manfred, Riching, Kristin M, Daniels, Danette L, Spallarossa, Andrea, Ciulli, Alessio
• Format: Journal Article
• Language: English
• Published: WASHINGTON American Chemical Society 24.01.2019; Amer Chemical Soc
• Subjects: Chemistry, Medicinal; Chromosomal Proteins, Non-Histone - chemistry; Chromosomal Proteins, Non-Histone - metabolism; Drug Design; HeLa Cells; Humans; Kinetics; Life Sciences & Biomedicine; Pharmacology & Pharmacy; Protein Binding; Proteolysis; Proteome - analysis; Science & Technology; Structure-Activity Relationship; Thermodynamics; Transcription Factors - chemistry; Transcription Factors - metabolism; Ubiquitination; Von Hippel-Lindau Tumor Suppressor Protein - chemistry; Von Hippel-Lindau Tumor Suppressor Protein - metabolism; INDUCED PROTEIN-DEGRADATION; STRUCTURE-GUIDED DESIGN; RECOGNITION; SWI/SNF COMPLEXES; TUMOR-SUPPRESSOR GENE; ALPHA; BROMODOMAIN; DISCOVERY; E3 UBIQUITIN LIGASE; SUBUNIT
• ISSN: 0022-2623; 1520-4804
• DOI: 10.1021/acs.jmedchem.8b01413

Developing PROTACs to redirect the ubiquitination activity of E3 ligases and potently degrade a target protein within cells can be a lengthy and unpredictable process, and it remains unclear whether any combination of E3 and target might be productive for degradation. We describe a probe-quality degrader for a ligase–target pair deemed unsuitable: the von Hippel–Lindau (VHL) and BRD9, a bromodomain-containing subunit of the SWI/SNF chromatin remodeling complex BAF. VHL-based degraders could be optimized from suboptimal compounds in two rounds by systematically varying conjugation patterns and linkers and monitoring cellular degradation activities, kinetic profiles, and ubiquitination, as well as ternary complex formation thermodynamics. The emerged structure–activity relationships guided the discovery of VZ185, a potent, fast, and selective degrader of BRD9 and of its close homolog BRD7. Our findings qualify a new chemical tool for BRD7/9 knockdown and provide a roadmap for PROTAC development against seemingly incompatible target–ligase combinations.