Discovery of Potent Small-Molecule Inhibitors of Ubiquitin-Conjugating Enzyme UbcH5c from α-Santonin Derivatives

J Med Chem. 2017 Aug 24;60(16):6828-6852. doi: 10.1021/acs.jmedchem.6b01829. Epub 2017 Aug 2.

Abstract

As a therapeutic target for antitumor necrosis factor (TNF)-α interventions, UbcH5c is one of the key ubiquitin-conjugating enzymes catalyzing ubiquitination during TNF-α-triggered nuclear factor kappa B (NF-κB) activation. In the present study, three series of analogues were designed and synthesized from α-santonin, and their UbcH5c inhibitory activities were screened by Western blotting and NF-κB luciferase assay. Further BIAcore, in-gel fluorescence imaging, and immunoprecipitation assays demonstrated that compound 6d exhibited robust and specific inhibition of UbcH5c, exceeding that of the positive compound 1 (IJ-5). Mechanistic investigations revealed that compound 6d preferentially bound to and inactivated UbcH5c by forming a covalent adduct with its active site Cys85. Furthermore, compound 6d exhibited potent anti-inflammatory activity against complete Freund's adjuvant-induced adjuvant arthritis in vivo. These findings suggest that the novel α-santonin-derived UbcH5c inhibitor 6d is a promising lead compound for the development of new antirheumatoid arthritis (RA) agent.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Anti-Inflammatory Agents, Non-Steroidal / chemical synthesis
  • Anti-Inflammatory Agents, Non-Steroidal / pharmacokinetics
  • Anti-Inflammatory Agents, Non-Steroidal / pharmacology
  • Benzofurans / chemical synthesis
  • Benzofurans / pharmacokinetics
  • Benzofurans / pharmacology*
  • Drug Stability
  • Fibroblasts / metabolism
  • HeLa Cells
  • Humans
  • I-kappa B Kinase / metabolism
  • Male
  • Mice
  • Microsomes, Liver / metabolism
  • NF-kappa B / metabolism
  • Rats, Sprague-Dawley
  • Santonin / analogs & derivatives*
  • Santonin / chemical synthesis
  • Santonin / pharmacokinetics
  • Santonin / pharmacology*
  • Signal Transduction
  • Structure-Activity Relationship
  • Tumor Necrosis Factor-alpha / metabolism
  • Ubiquitin-Conjugating Enzymes / antagonists & inhibitors*
  • Ubiquitination

Substances

  • 8-((2-bromobenzyl)oxy)-6,9-dimethyl-3-methylene-3a,4,5,9b-tetrahydronaphtho(1,2-b)furan-2(3H)-one
  • Anti-Inflammatory Agents, Non-Steroidal
  • Benzofurans
  • IKBKG protein, human
  • NF-kappa B
  • Tumor Necrosis Factor-alpha
  • Santonin
  • UBE2D3 protein, human
  • Ubiquitin-Conjugating Enzymes
  • I-kappa B Kinase