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.
Hao Chen  1 Guozhen Wu  1 Shuang Gao  1 Ruihua Guo  1 Zeng Zhao  1 Hu Yuan  2 Shanxiang Liu  1 Jian Wu  3 Xiaolong Lu  4 Xing Yuan  1 Zongmin Yu  1 Xianpeng Zu  1 Ning Xie  5 Niao Yang  1 Zhenlin Hu  1 Qingyan Sun  2 Weidong Zhang  1  2  6
Affiliations
  • 1. School of Pharmacy, Second Military Medical University , Shanghai 200433, China.
  • 2. Shanghai Institute of Pharmaceutical Industry , Shanghai 200040, China.
  • 3. Progenra, Inc. , 277 Great Valley Parkway, Malvern, Pennsylvania 19355, United States.
  • 4. Lifesensors, Inc. , 271 Great Valley Parkway, Malvern, Pennsylvania 19355, United States.
  • 5. State Key Laboratory of Innovative Natural Medicine and TCM Injections, Jiangxi Qingfeng Pharmaceutical Co., Ltd. , Ganzhou 341000, Jiangxi, China.
  • 6. Institute of Interdisciplinary Research Complex, Shanghai University of Traditional Chinese Medicine , Shanghai 201210, China.
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.

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