Fluorovinylsulfones and -Sulfonates as Potent Covalent Reversible Inhibitors of the Trypanosomal Cysteine Protease Rhodesain: Structure-Activity Relationship, Inhibition Mechanism, Metabolism, and In Vivo Studies

  • J Med Chem. 2021 Aug 26;64(16):12322-12358. doi: 10.1021/acs.jmedchem.1c01002.
Sascha Jung  1 ,  Natalie Fuchs  1 ,  Patrick Johe  1 ,  Annika Wagner  2 ,  Erika Diehl  2 ,  Tri Yuliani  3 ,  Collin Zimmer  1 ,  Fabian Barthels  1 ,  Robert A Zimmermann  1 ,  Philipp Klein  4 ,  Waldemar Waigel  5 ,  Jessica Meyr  5 ,  Till Opatz  4 ,  Stefan Tenzer  6 ,  Ute Distler  6 ,  Hans-Joachim Räder  7 ,  Christian Kersten  1 ,  Bernd Engels  5 ,  Ute A Hellmich  2  8 ,  Jochen Klein  3 ,  Tanja Schirmeister  1
Affiliations
  • 1. Institute of Pharmaceutical and Biomedical Sciences (IPBS), Johannes Gutenberg University, Staudinger Weg 5, 55128 Mainz, Germany.
  • 2. Department of Chemistry, Biochemistry Section, Johannes Gutenberg University, Hanns-Dieter-Hüsch-Weg 17, 55128 Mainz, Germany.
  • 3. Institute for Pharmacology and Clinical Pharmacy, Goethe University, Max-von-Laue-Str. 9, 60439 Frankfurt, Germany.
  • 4. Department of Chemistry, Organic Chemistry Section, Johannes Gutenberg University, Duesbergweg 10-14, 55128 Mainz, Germany.
  • 5. Department of Physical and Theoretical Chemistry, Julius-Maximilians-University, Emil-Fischer-Str. 42, 97074 Würzburg, Germany.
  • 6. Institute for Immunology, University Medical Center, Johannes Gutenberg University, Langenbeckstraße 1, 55131 Mainz, Germany.
  • 7. Max Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany.
  • 8. Center for Biomolecular Magnetic Resonance (BMRZ), Goethe University, Max-von-Laue-Str. 9, 60438 Frankfurt, Germany.
PMID: 34378914 DOI: 10.1021/acs.jmedchem.1c01002
Abstract

Rhodesain is a major cysteine protease of Trypanosoma brucei rhodesiense, a pathogen causing Human African Trypanosomiasis, and a validated drug target. Recently, we reported the development of α-halovinylsulfones as a new class of covalent reversible cysteine Protease Inhibitors. Here, α-fluorovinylsulfones/-sulfonates were optimized for rhodesain based on molecular modeling approaches. 2d, the most potent and selective inhibitor in the series, shows a single-digit nanomolar affinity and high selectivity toward mammalian cathepsins B and L. Enzymatic dilution assays and MS experiments indicate that 2d is a slow-tight binder (Ki = 3 nM). Furthermore, the nonfluorinated 2d-(H) shows favorable metabolism and biodistribution by accumulation in mice brain tissue after intraperitoneal and oral administration. The highest antitrypanosomal activity was observed for inhibitors with an N-terminal 2,3-dihydrobenzo[b][1,4]dioxine group and a 4-Me-Phe residue in P2 (2e/4e) with nanomolar EC50 values (0.14/0.80 μM). The different mechanisms of reversible and irreversible inhibitors were explained using QM/MM calculations and MD simulations.