Structure-based discovery of (S)-2-amino-6-(4-fluorobenzyl)-5,6,11,11a-tetrahydro-1H-imidazo[1',5':1,6]pyrido[3,4-b]indole-1,3(2H)-dione as low nanomolar, orally bioavailable autotaxin inhibitor

Chem Biol Drug Des. 2022 Mar;99(3):496-503. doi: 10.1111/cbdd.14017. Epub 2022 Jan 3.

Abstract

Inhibition of extracellular secreted enzyme autotaxin (ATX) represents an attractive strategy for the development of new therapeutics to treat various diseases and a few inhibitors entered in clinical trials. We herein describe structure-based design, synthesis, and biological investigations revealing a potent and orally bioavailable ATX inhibitor 1. During the molecular docking and scoring studies within the ATX enzyme (PDB-ID: 4ZGA), the S-enantiomer (Gscore = -13.168 kcal/mol) of the bound ligand PAT-494 scored better than its R-enantiomer (Gscore = -9.562 kcal/mol) which corroborated with the reported observation and analysis of the results suggested the scope of manipulation of the hydantoin substructure in PAT-494. Accordingly, the docking-based screening of a focused library of 10 compounds resulted in compound 1 as a better candidate for pharmacological studies. Compound 1 was synthesized from L-tryptophan and evaluated against ATX enzymatic activities with an IC50 of 7.6 and 24.6 nM in biochemical and functional assays, respectively. Further, ADME-PK studies divulged compound 1 as non-cytotoxic (19.02% cell growth inhibition at 20 μM in human embryonic kidney cells), metabolically stable against human liver microsomes (CLint = 15.6 μl/min/mg; T1/2 = 113.2 min) with solubility of 4.82 μM and orally bioavailable, demonstrating its potential to be used for in vivo experiments.

Keywords: ADME; PK; aminohydantoin; autotaxin; docking; drug design; in vitro.

MeSH terms

  • Administration, Oral
  • Animals
  • Binding Sites
  • Drug Design*
  • Drug Stability
  • Enzyme Inhibitors / chemistry*
  • Enzyme Inhibitors / metabolism
  • Enzyme Inhibitors / pharmacokinetics
  • Half-Life
  • Humans
  • Imidazoles / chemistry
  • Indoles / chemistry*
  • Indoles / metabolism
  • Indoles / pharmacokinetics
  • Microsomes, Liver / metabolism
  • Molecular Docking Simulation
  • Phosphoric Diester Hydrolases / chemistry*
  • Phosphoric Diester Hydrolases / metabolism
  • Pyridines / chemistry
  • Rats
  • Rats, Sprague-Dawley
  • Stereoisomerism

Substances

  • Enzyme Inhibitors
  • Imidazoles
  • Indoles
  • Pyridines
  • Phosphoric Diester Hydrolases
  • alkylglycerophosphoethanolamine phosphodiesterase