1. Academic Validation
  2. GSK1562590, a slowly dissociating urotensin-II receptor antagonist, exhibits prolonged pharmacodynamic activity ex vivo

GSK1562590, a slowly dissociating urotensin-II receptor antagonist, exhibits prolonged pharmacodynamic activity ex vivo

  • Br J Pharmacol. 2010 Sep;161(1):207-28. doi: 10.1111/j.1476-5381.2010.00889.x.
D J Behm 1 N V Aiyar A R Olzinski J J McAtee M A Hilfiker J W Dodson S E Dowdell G Z Wang K B Goodman C A Sehon M R Harpel R N Willette M J Neeb C A Leach S A Douglas
Affiliations

Affiliation

  • 1 Metabolic Pathways Center of Excellence for Drug Discovery, GlaxoSmithKline, King of Prussia, PA, USA. david.j.behm@gsk.com
Abstract

Background and purpose: Recently identified antagonists of the urotensin-II (U-II) receptor (UT) are of limited utility for investigating the (patho)physiological role of U-II due to poor potency and limited selectivity and/or intrinsic activity.

Experimental approach: The pharmacological properties of two novel UT antagonists, GSK1440115 and GSK1562590, were compared using multiple bioassays.

Key results: GSK1440115 (pK(i)= 7.34-8.64 across species) and GSK1562590 (pK(i)= 9.14-9.66 across species) are high affinity ligands of mammalian recombinant (mouse, rat, cat, monkey, human) and native (SJRH30 cells) UT. Both compounds exhibited >100-fold selectivity for UT versus 87 distinct mammalian GPCR, Enzyme, ion channel and neurotransmitter uptake targets. GSK1440115 showed competitive antagonism at UT in arteries from all species tested (pA(2)= 5.59-7.71). In contrast, GSK1562590 was an insurmountable UT antagonist in rat, cat and hUT transgenic mouse arteries (pK(b)= 8.93-10.12 across species), but a competitive antagonist in monkey arteries (pK(b)= 8.87-8.93). Likewise, GSK1562590 inhibited the hU-II-induced systemic pressor response in anaesthetized cats at a dose 10-fold lower than that of GSK1440115. The antagonistic effects of GSK1440115, but not GSK1562590, could be reversed by washout in rat isolated aorta. In ex vivo studies, GSK1562590 inhibited hU-II-induced contraction of rat aorta for at least 24 h following dosing. Dissociation of GSK1562590 binding was considerably slower at rat than monkey UT.

Conclusions and implications: Whereas both GSK1440115 and GSK1562590 represent high-affinity/selective UT antagonists suitable for assessing the (patho)physiological role of U-II, only GSK1562590 exhibited sustained UT residence time and improved preclinical efficacy in vivo.

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