Modulating the Potency of BRD4 PROTACs at the Systems Level with Amine-Acid Coupling Reactions

J Med Chem. 2025 Jan 9;68(1):405-420. doi: 10.1021/acs.jmedchem.4c02047. Epub 2024 Dec 17.

Abstract

Protein degradation using proteolysis targeting chimeras (PROTACs) represents a promising therapeutic strategy. PROTACs are heterobifunctional molecules that consist of a target-binding moiety and an E3 ligase binding moiety, connected by a linker. These fragments are frequently united via amide bonds. While straightforward to synthesize, amides may impart suboptimal drug properties to the overall molecule. From a systems level perspective, we envisioned that the potency of PROTACs could be modulated through selection of reaction conditions─wherein different catalysts produce distinct linkers from the same two building blocks. We present a suite of BRD4 PROTAC degraders prepared via four new amine-acid coupling reactions alongside the classic amide coupling. Our findings reveal that variations in reaction conditions affect the physicochemical properties of PROTACs, resulting in a spectrum of properties. Notably, several new PROTACs demonstrated enhanced BRD4 degradation efficacy compared to those employing amide linkers, emphasizing the potential of systems chemistry as a therapeutic optimization strategy.

MeSH terms

  • Amines* / chemical synthesis
  • Amines* / chemistry
  • Amines* / pharmacology
  • Bromodomain Containing Proteins
  • Cell Cycle Proteins* / metabolism
  • Humans
  • Proteolysis Targeting Chimera
  • Proteolysis* / drug effects
  • Transcription Factors* / antagonists & inhibitors
  • Transcription Factors* / metabolism
  • Ubiquitin-Protein Ligases / metabolism

Substances

  • Transcription Factors
  • BRD4 protein, human
  • Cell Cycle Proteins
  • Amines
  • Ubiquitin-Protein Ligases
  • Proteolysis Targeting Chimera
  • Bromodomain Containing Proteins