Piperazine squaric acid diamides, a novel class of allosteric P2X7 receptor antagonists

Eur J Med Chem. 2021 Dec 15:226:113838. doi: 10.1016/j.ejmech.2021.113838. Epub 2021 Sep 16.

Abstract

The P2X7 receptor (P2X7R) stands out among the purinergic receptors due to its strong involvement in the regulation of tumor growth and metastasis formation as well as in innate immune responses and afferent signal transmission. Numerous studies have pointed out the beneficial effects of P2X7R antagonism for the treatment of a variety of cancer types, inflammatory diseases, and chronic pain. Herein we describe the development of novel P2X7R antagonists, incorporating piperazine squaric diamides as a central element. Besides improving the antagonists' potency from pIC50 values of 5.7-7.6, ADME properties (logD7.4 value, plasma protein binding, in vitro metabolic stability) of the generated compounds were investigated and optimized to provide novel P2X7R antagonists with drug-like properties. Furthermore, docking studies revealed the antagonists binding to the allosteric binding pocket in two distinct binding poses, depending on the substitution of the central piperazine moiety.

Keywords: Allosteric; Antagonists; P2X; P2X7 receptor; Squaric acid.

MeSH terms

  • Cyclobutanes / chemical synthesis
  • Cyclobutanes / chemistry
  • Cyclobutanes / pharmacology*
  • Diamide / chemical synthesis
  • Diamide / chemistry
  • Diamide / pharmacology*
  • Dose-Response Relationship, Drug
  • HEK293 Cells
  • Humans
  • Molecular Structure
  • Piperazine / chemical synthesis
  • Piperazine / chemistry
  • Piperazine / pharmacology*
  • Purinergic P2X Receptor Antagonists / chemical synthesis
  • Purinergic P2X Receptor Antagonists / chemistry
  • Purinergic P2X Receptor Antagonists / pharmacology*
  • Receptors, Purinergic P2X / metabolism*
  • Structure-Activity Relationship
  • Tumor Cells, Cultured

Substances

  • Cyclobutanes
  • Purinergic P2X Receptor Antagonists
  • Receptors, Purinergic P2X
  • Diamide
  • Piperazine
  • squaric acid