1. Academic Validation
  2. Mechanism-specific assay design facilitates the discovery of Nav1.7-selective inhibitors

Mechanism-specific assay design facilitates the discovery of Nav1.7-selective inhibitors

  • Proc Natl Acad Sci U S A. 2018 Jan 23;115(4):E792-E801. doi: 10.1073/pnas.1713701115.
Tania Chernov-Rogan 1 Tianbo Li 1 Gang Lu 1 Henry Verschoof 2 Kuldip Khakh 2 Steven W Jones 1 Maureen H Beresini 1 Chang Liu 1 Daniel F Ortwine 3 Steven J McKerrall 3 David H Hackos 4 Daniel Sutherlin 3 Charles J Cohen 2 Jun Chen 5
Affiliations

Affiliations

  • 1 Department of Biochemical and Cellular Pharmacology, Genentech Inc., San Francisco, CA 94080.
  • 2 Xenon Pharmaceuticals, Burnaby, BC V5G 4W8, Canada.
  • 3 Department of Chemistry, Genentech Inc., San Francisco, CA 94080.
  • 4 Department of Neuroscience, Genentech Inc., San Francisco, CA 94080.
  • 5 Department of Biochemical and Cellular Pharmacology, Genentech Inc., San Francisco, CA 94080; chenj144@gene.com.
Abstract

Many ion channels, including Nav1.7, Cav1.3, and Kv1.3, are linked to human pathologies and are important therapeutic targets. To develop efficacious and safe drugs, subtype-selective modulation is essential, but has been extremely difficult to achieve. We postulate that this challenge is caused by the poor assay design, and investigate the Nav1.7 membrane potential assay, one of the most extensively employed screening assays in modern drug discovery. The assay uses veratridine to activate channels, and compounds are identified based on the inhibition of veratridine-evoked activities. We show that this assay is biased toward nonselective pore blockers and fails to detect the most potent, selective voltage-sensing domain 4 (VSD4) blockers, including PF-05089771 (PF-771) and GX-936. By eliminating a key binding site for pore blockers and replacing veratridine with a VSD-4 binding activator, we directed the assay toward non-pore-blocking mechanisms and discovered Nav1.7-selective chemical scaffolds. Hence, we address a major hurdle in Nav1.7 drug discovery, and this mechanistic approach to assay design is applicable to Cav3.1, Kv1.3, and many other ion channels to facilitate drug discovery.

Keywords

1KαPMTX; N1742K; Nav1.7; VSD4; veratridine.

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