GS-5759, a Bifunctional β2-Adrenoceptor Agonist and Phosphodiesterase 4 Inhibitor for Chronic Obstructive Pulmonary Disease with a Unique Mode of Action: Effects on Gene Expression in Human Airway Epithelial Cells

(R)-6-[(3-{[4-(5-{[2-hydroxy-2-(8-hydroxy-2-oxo-1,2-dihydroquinolin-5-yl)ethyl]amino}pent-1-yn-1-yl) phenyl] carbamoyl} phenyl)sulphonyl]-4-[(3-methoxyphenyl)amino]-8-methylquinoline-3carboxamidetrifluoroacetic acid (GS-5759) is a bifunctional ligand composed of a quinolinone-containing pharmacophore [beta(2)-adrenoceptor agonist orthostere (beta(2)A)] found in several beta(2)-adrenoceptor agonists, including indacaterol, linked covalently to a phosphodiesterase 4 (PDE4) inhibitor related to 6-[3(dimethylcarbamoyl)benzenesulphonyl]-4-[(3-methoxyphenyl)amino]-8-methylquinoline-3-carboxamide (GSK 256066) by a pent-1-yn-1-ylbenzene spacer. GS-5759 had a similar affinity for PDE4B1 and the native beta(2)-adrenoceptor expressed on BEAS-2B human airway epithelial cells. However, compared with the monofunctional parent compound, beta(2)A, the KA of GS-5759 for the beta(2)-adrenoceptor was 35-fold lower. Schild analysis determined that the affinities of the b-adrenoceptor antagonists, (2R, 3R)-1-[(2,3-dihydro-7-methyl-1H-inden-4-yl)oxy]-3-[(1-methylethyl) amino]-2-butanol (ICI 118551) and propranolol, were agonist-dependent, being significantly lower for GS-5759 than beta(2)A. Collectively, these data can be explained by forced proximity, bivalent binding where the pharmacophore in GS-5759 responsible for PDE4 inhibition also interacts with a nonallosteric domain within the beta(2)-adrenoceptor that enhances the affinity of beta(2)A for the orthosteric site. Microarray analyses revealed that, after 2-hour exposure, GS-5759 increased the expression of.3500 genes in BEAS-2B cells that were highly rank-order correlated with gene expression changes produced by indacaterol and GSK 256066 in combination (Ind/GSK). Moreover, the line of regression began close to the origin with a slope of 0.88, indicating that the magnitude of most gene expression changes produced by Ind/GSK was quantitatively replicated by GS-5759. Thus, GS-5759 is a novel compound exhibiting dual beta(2)-adrenoceptor agonism and PDE4 inhibition with potential to interact on target tissues in a synergistic manner. Such polypharmacological behavior may be particularly effective in chronic obstructive pulmonary disease and other complex disorders where multiple processes interact to promote disease pathogenesis and progression.