Characterization of Hedgehog Acyltransferase Inhibitors Identifies a Small Molecule Probe for Hedgehog Signaling by Cancer Cells

  • ACS Chem Biol. 2016 Dec 16;11(12):3256-3262. doi: 10.1021/acschembio.6b00896.
Ursula R Rodgers  1 ,  Thomas Lanyon-Hogg  2 ,  Naoko Masumoto  2 ,  Markus Ritzefeld  2 ,  Rosemary Burke  3 ,  Julian Blagg  3 ,  Anthony I Magee  1 ,  Edward W Tate  2
Affiliations
  • 1. Molecular Medicine Section, National Heart & Lung Institute, Imperial College London , London SW7 2AZ, United Kingdom.
  • 2. Department of Chemistry, Imperial College London , London SW7 2AZ, United Kingdom.
  • 3. Cancer Research UK Cancer Therapeutics Unit, The Institute of Cancer Research , London, SW7 3RP, United Kingdom.
PMID: 27779865 DOI: 10.1021/acschembio.6b00896
Abstract

The Sonic Hedgehog (Shh) signaling pathway plays a critical role during embryonic development and Cancer progression. N-terminal palmitoylation of Shh by Hedgehog Acyltransferase (Hhat) is essential for efficient signaling, raising interest in Hhat as a novel drug target. A recently identified series of dihydrothienopyridines has been proposed to function via this mode of action; however, the lead compound in this series (RUSKI-43) was subsequently shown to possess cytotoxic activity unrelated to canonical Shh signaling. To identify a selective chemical probe for cellular studies, we profiled three RUSKI compounds in orthogonal cell-based assays. We found that RUSKI-43 exhibits off-target cytotoxicity, masking its effect on Hhat-dependent signaling, hence results obtained with this compound in cells should be treated with caution. In contrast, RUSKI-201 showed no off-target cytotoxicity, and quantitative whole-proteome palmitoylation profiling with a bioorthogonal alkyne-palmitate reporter demonstrated specific inhibition of Hhat in cells. RUSKI-201 is the first selective Hhat chemical probe in cells and should be used in future studies of Hhat catalytic function.

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