Further studies on 2-arylacetamide pyridazin-3(2H)-ones: design, synthesis and evaluation of 4,6-disubstituted analogs as formyl peptide receptors (FPRs) agonists

Eur J Med Chem. 2013 Jun;64:512-28. doi: 10.1016/j.ejmech.2013.03.066. Epub 2013 Apr 8.


Formyl peptide receptors (FPRs) play an essential role in the regulation of endogenous inflammation and immunity. In the present studies, a large series of pyridazin-3(2H)-one derivatives bearing an arylacetamide chain at position 2 was synthesized and tested for FPR agonist activity. The pyridazin-3(2H)-one ring was confirmed to be an appropriate scaffold to support FPR agonist activity, and its modification at the 4 and 6 positions led to the identification of additional active agonists, which induced intracellular Ca(2+) flux in HL-60 cells transfected with either FPR1, FPR2, or FPR3. Seven formyl peptide receptor 1 (FPR1)-specific and several mixed FPR1/FPR2 dual agonists were identified with low micromolar EC50 values. Furthermore, these agonists also activated human neutrophils, inducing intracellular Ca(2+) flux and chemotaxis. Finally, molecular docking studies indicated that the most potent pyridazin-3(2H)-ones overlapped in their best docking poses with fMLF and WKYMVM peptides in the FPR1 and FPR2 ligand binding sites, respectively. Thus, pyridazinone-based compounds represent potential lead compounds for further development of selective and/or potent FPR agonists.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Acetamides / chemical synthesis
  • Acetamides / chemistry
  • Acetamides / pharmacology*
  • Antineoplastic Agents / chemical synthesis
  • Antineoplastic Agents / chemistry
  • Antineoplastic Agents / pharmacology*
  • Cell Proliferation / drug effects
  • Cell Survival / drug effects
  • Dose-Response Relationship, Drug
  • Drug Design*
  • Drug Screening Assays, Antitumor
  • HL-60 Cells
  • Humans
  • Models, Molecular
  • Molecular Structure
  • Neutrophils / drug effects
  • Neutrophils / metabolism
  • Pyridazines / chemical synthesis
  • Pyridazines / chemistry
  • Pyridazines / pharmacology*
  • Receptors, Formyl Peptide / agonists*
  • Structure-Activity Relationship
  • Tumor Cells, Cultured


  • Acetamides
  • Antineoplastic Agents
  • Pyridazines
  • Receptors, Formyl Peptide