2. Academic Validation
  3. Selective Glucocorticoid Receptor Properties of GSK866 Analogs with Cysteine Reactive Warheads

Selective Glucocorticoid Receptor Properties of GSK866 Analogs with Cysteine Reactive Warheads

  • Front Immunol. 2017 Nov 1:8:1324. doi: 10.3389/fimmu.2017.01324.
Chandra S Chirumamilla 1,  Ajay Palagani 1,  Balu Kamaraj 2,  Ken Declerck 1,  Marinus W C Verbeek 1,  Ryabtsova Oksana 3,  Karolien De Bosscher 4,  Nadia Bougarne 4,  Bart Ruttens 5,  Kris Gevaert 5,  René Houtman 6,  Winnok H De Vos 7,  Jurgen Joossens 3,  Pieter Van Der Veken 3,  Koen Augustyns 3,  Xaveer Van Ostade 1,  Annemie Bogaerts 2,  Hans De Winter 3,  Wim Vanden Berghe 1
Affiliations

Affiliations

  • 1 Laboratory of Protein Chemistry, Proteomics and Epigenetic Signalling, Department of Biomedical Sciences, University of Antwerp, Antwerp, Belgium.
  • 2 Research Group PLASMANT, Department of Chemistry, University of Antwerp, Antwerp, Belgium.
  • 3 Medicinal Chemistry, Department of Pharmaceutical Sciences, University of Antwerp, Antwerp, Belgium.
  • 4 Receptor Research Laboratories, Nuclear Receptor Lab (NRL) and Cytokine Receptor Lab (CRL), VIB-UGent Center for Medical Biotechnology, Ghent University, Ghent, Belgium.
  • 5 Center for Medical Biotechnology, Department of Biochemistry, VIB, Ghent University, Ghent, Belgium.
  • 6 PamGene International B.V., Den Bosch, Netherlands.
  • 7 Laboratory of Cell Biology and Histology, Department of Veterinary Sciences, University of Antwerp, Antwerp, Belgium.
PMID: 29163463 DOI: 10.3389/fimmu.2017.01324
Abstract

Synthetic glucocorticoids (GC) are the mainstay therapy for treatment of acute and chronic inflammatory disorders. Due to the high adverse effects associated with long-term use, GC pharmacology has focused since the nineties on more selective GC ligand-binding strategies, classified as selective Glucocorticoid Receptor (GR) agonists (SEGRAs) or selective Glucocorticoid Receptor modulators (SEGRMs). In the current study, GSK866 analogs with electrophilic covalent-binding warheads were developed with potential SEGRA properties to improve their clinical safety profile for long-lasting topical skin disease applications. Since the off-rate of a covalently binding drug is negligible compared to that of a non-covalent drug, its therapeutic effects can be prolonged and typically, smaller doses of the drug are necessary to reach the same level of therapeutic efficacy, thereby potentially reducing systemic side effects. Different analogs of SEGRA GSK866 coupled to cysteine reactive warheads were characterized for GR potency and selectivity in various biochemical and cellular assays. GR- and NFκB-dependent reporter gene studies show favorable anti-inflammatory properties with reduced GR transactivation of two non-steroidal GSK866 analogs UAMC-1217 and UAMC-1218, whereas UAMC-1158 and UAMC-1159 compounds failed to modulate cellular GR activity. These results were further supported by GR immuno-localization and S211 phospho-GR western analysis, illustrating significant GR phosphoactivation and nuclear translocation upon treatment of GSK866, UAMC-1217, or UAMC-1218, but not in case of UAMC-1158 or UAMC-1159. Furthermore, mass spectrometry analysis of tryptic Peptides of recombinant GR ligand-binding domain (LBD) bound to UAMC-1217 or UAMC-1218 confirmed covalent cysteine-dependent GR binding. Finally, molecular dynamics simulations, as well as Glucocorticoid Receptor ligand-binding domain (GR-LBD) coregulator interaction profiling of the GR-LBD bound to GSK866 or its covalently binding analogs UAMC-1217 or UAMC-1218 revealed subtle conformational differences that might underlie their SEGRA properties. Altogether, GSK866 analogs UAMC-1217 and UAMC-1218 hold promise as a novel class of covalent-binding SEGRA ligands for the treatment of topical inflammatory skin disorders.

Keywords

NFkB; SEGRA; covalent warhead; cysteine; electrophilic; glucocorticoid receptor.

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