Lookup NU author(s): Professor Mike Waring
This work is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License (CC BY-NC 4.0).
The duration of action of adenosine A2A receptor (A2A) agonists is critical for their clinical efficacy, and we sought to better understand how this can be optimized. The in vitro temporal response profiles of a panel of A2A agonists were studied using cAMP assays in recombinantly (CHO) and endogenously (SH-SY5Y) expressing cells. Some agonists (e.g. 3cd; UK-432,097) but not others (e.g. 3ac; CGS-21680) demonstrated sustained wash-resistant agonism, where residual receptor activation continued after washout. The ability of an antagonist to reverse pre-established agonist responses was used as a surrogate read-out for agonist dissociation kinetics, and together with radioligand bindingstudies suggested a role for slow off-rate in driving sustained effects. One compound, 3ch, showed particularly marked sustained effects, with a reversal t½ > 6 hours and close to maximal effects that remained for at least 5 hours after washing. Based on the SAR of these compounds, we suggest that lipophilic N6 and bulky C2 substituents can promote stable and long-lived binding events leading to sustained agonist responses, although a high compound logD is not necessary. This provides new insight into the binding interactions of these ligands and we anticipate that this information could facilitate the rational design of novel long-acting A2A agonists with improved clinical efficacy.
Author(s): Hothersall JD, Guo D, Sarda S, Sheppard RJ, Chen H, Keur W, Waring MJ, IJzerman AP, Hill SJ, Dale IL, Rawlins PB
Publication type: Article
Publication status: Published
Journal: Molecular Pharmacology
Print publication date: 01/01/2017
Online publication date: 02/12/2016
Acceptance date: 28/10/2016
Date deposited: 07/11/2016
ISSN (print): 0026-895X
ISSN (electronic): 1521-0111
Publisher: American Society for Pharmacology and Experimental Therapeutics
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