Fluorescent-Labeled Selective Adenosine A 2B Receptor Antagonist Enables Competition Binding Assay by Flow Cytometry

J Med Chem. 2018 May 24;61(10):4301-4316. doi: 10.1021/acs.jmedchem.7b01627. Epub 2018 May 15.

Abstract

Fluorescent ligands represent powerful tools for biological studies and are considered attractive alternatives to radioligands. In this study, we developed fluorescent antagonists for A2B adenosine receptors (A2BARs), which are targeted by antiasthmatic xanthines and were proposed as novel targets in immuno-oncology. Our approach was to merge a small borondipyrromethene (BODIPY) derivative with the pharmacophore of 8-substituted xanthine derivatives. On the basis of the design, synthesis, and evaluation of model compounds, several fluorescent ligands were synthesized. Compound 29 (PSB-12105), which displayed high affinity for human, rat, and mouse A2BARs ( Ki = 0.2-2 nM) and high selectivity for this AR subtype, was selected for further studies. A homology model of the human A2BAR was generated, and docking studies were performed. Moreover, 29 allowed us to establish a homogeneous receptor-ligand binding assay using flow cytometry. These compounds constitute the first potent, selective fluorescent A2BAR ligands and are anticipated to be useful for a variety of applications.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adenosine A2 Receptor Antagonists / pharmacology*
  • Animals
  • Binding, Competitive
  • CHO Cells
  • Cell Proliferation
  • Cricetinae
  • Cricetulus
  • Cyclic AMP / metabolism
  • Flow Cytometry / methods*
  • Fluorescent Dyes / chemistry*
  • Humans
  • Mice
  • Models, Molecular
  • Molecular Structure
  • Protein Binding
  • Protein Conformation
  • Radioligand Assay
  • Rats
  • Receptor, Adenosine A2B / chemistry*

Substances

  • Adenosine A2 Receptor Antagonists
  • Fluorescent Dyes
  • Receptor, Adenosine A2B
  • Cyclic AMP