ABSTRACT
Installation of sites for metabolism in the lead compound PHA-767408 was the key focus of the IKK-2 inhaled program. This paper reports our efforts to identify a novel series of aminopyridinecarboxamide-based IKK-2 inhibitors, which display low nanomolar potency against IKK-2 with long duration of action (DOA), and metabolically labile to phase I and/or phase II metabolizing enzymes with potential capability for multiple routes of clearance. Several compounds have demonstrated their potential usefulness in the treatment of asthma and chronic obstructive pulmonary disease (COPD).
Subject(s)
Aminopyridines/chemical synthesis , Asthma/drug therapy , I-kappa B Kinase/antagonists & inhibitors , Niacinamide/analogs & derivatives , Protein Kinase Inhibitors/chemical synthesis , Pulmonary Disease, Chronic Obstructive/drug therapy , Pyrazoles/chemical synthesis , Administration, Inhalation , Aminopyridines/chemistry , Aminopyridines/pharmacology , Binding, Competitive , Drug Design , HEK293 Cells , Humans , Indazoles/chemistry , Indazoles/metabolism , Indazoles/pharmacology , Isonicotinic Acids/chemistry , Isonicotinic Acids/metabolism , Isonicotinic Acids/pharmacology , Microsomes, Liver/drug effects , Models, Molecular , Molecular Structure , Molecular Targeted Therapy , Niacinamide/chemical synthesis , Niacinamide/chemistry , Niacinamide/metabolism , Niacinamide/pharmacology , Phenethylamines/metabolism , Potassium Channel Blockers/metabolism , Protein Kinase Inhibitors/chemistry , Protein Kinase Inhibitors/pharmacology , Pyrazoles/chemistry , Pyrazoles/metabolism , Pyrazoles/pharmacology , Structure-Activity Relationship , Sulfonamides/metabolismABSTRACT
Activation of the p38 kinase pathway in immune cells leads to the transcriptional and translational regulation of proinflammatory cytokines. Mitogen-activated protein kinase-activated protein kinase 2 (MK2), a direct downstream substrate of p38 kinase, regulates lipopolysaccharide (LPS)-stimulated tumor necrosis factor alpha (TNFalpha) and interleukin-6 (IL-6) production through modulating the stability and translation of these mRNAs. Developing small-molecule inhibitors of MK2 may yield anti-inflammatory efficacy with a different safety profile relative to p38 kinase inhibitors. This article describes the pharmacologic properties of a benzothiophene MK2 inhibitor, PF-3644022 [(10R)-10-methyl-3-(6-methylpyridin-3-yl)-9,10,11,12-tetrahydro-8H-[1,4]diazepino[5',6':4,5]thieno[3,2-f]quinolin-8-one]. PF-3644022 is a potent freely reversible ATP-competitive compound that inhibits MK2 activity (K(i) = 3 nM) with good selectivity when profiled against 200 human kinases. In the human U937 monocytic cell line or peripheral blood mononuclear cells, PF-3644022 potently inhibits TNFalpha production with similar activity (IC(50) = 160 nM). PF-3644022 blocks TNFalpha and IL-6 production in LPS-stimulated human whole blood with IC(50) values of 1.6 and 10.3 microM, respectively. Inhibition of TNFalpha in U937 cells and blood correlates closely with inhibition of phospho-heat shock protein 27, a target biomarker of MK2 activity. PF-3644022 displays good pharmacokinetic parameters in rats and is orally efficacious in both the rat acute LPS-induced TNFalpha model and the chronic streptococcal cell wall-induced arthritis model. Dose-dependent inhibition of TNFalpha production in the acute model and inhibition of paw swelling in the chronic model is observed with ED(50) values of 6.9 and 20 mg/kg, respectively. PF-3644022 efficacy in the chronic inflammation model is strongly correlated with maintaining a C(min) higher than the EC(50) measured in the rat LPS-induced TNFalpha model.
