Structure-activity relationships of the sustained effects of adenosine A2A receptor agonists driven by slow dissociation kinetics

Hothersall, J. Daniel; Guo, Dong; Sarda, Sunil; Sheppard, Robert J.; Chen, Hongming; Keur, Wesley; Waring, Michael J.; IJzerman, Adriaan P.; Hill, Stephen J.; Dale, Ian L.; Rawlins, Philip B.

Abstract

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 binding studies suggested a role for slow off-rate in driving sustained effects. One compound, 3ch, showed particularly marked sustained effects, with a reversal t1/2 > 6 hours and close to maximal effects that remained for at least 5 hours after washing. Based on the structure-activity relationship 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.

Citation

Hothersall, J. D., Guo, D., Sarda, S., Sheppard, R. J., Chen, H., Keur, W., Waring, M. J., IJzerman, A. P., Hill, S. J., Dale, I. L., & Rawlins, P. B. (2017). Structure-activity relationships of the sustained effects of adenosine A2A receptor agonists driven by slow dissociation kinetics. Molecular Pharmacology, 91(1), https://doi.org/10.1124/mol.116.105551

• Journal Article Type: Article
• Acceptance Date: Oct 28, 2016
• Publication Date: Jan 1, 2017
• Deposit Date: Feb 10, 2017
• Publicly Available Date: Feb 10, 2017
• Journal: Molecular Pharmacology
• Print ISSN: 0026-895X
• Electronic ISSN: 1521-0111
• Publisher: American Society for Pharmacology and Experimental Therapeutics
• Peer Reviewed: Peer Reviewed
• Volume: 91
• Issue: 1
• DOI: https://doi.org/10.1124/mol.116.105551
• Public URL: https://nottingham-repository.worktribe.com/output/830700
• Publisher URL: http://molpharm.aspetjournals.org/content/91/1/25
• Contract Date: Feb 10, 2017