ABSTRACT
The structure-activity relationships of 5,6-positions of aminopyridine carboxamide-based c-Jun N-terminal Kinase (JNK) inhibitors were explored to expand interaction with the kinase specificity and ribose-binding pockets. The syntheses of analogues and the impact of structural modification on in vitro potency and cellular activity are described.
Subject(s)
Amides/pharmacology , Aminopyridines/pharmacology , Enzyme Inhibitors/pharmacology , JNK Mitogen-Activated Protein Kinases/antagonists & inhibitors , Amides/chemistry , Aminopyridines/chemistry , Crystallography, X-Ray , Enzyme Inhibitors/chemistry , Inhibitory Concentration 50 , Protein Binding , Ribose/metabolism , Structure-Activity Relationship , Substrate SpecificityABSTRACT
C-Jun NH2 terminal kinases (JNKs) are important cell signaling enzymes. JNK1 plays a central role in linking obesity and insulin resistance. JNK2 and JNK3 may be involved in inflammatory and neurological disorders, respectively. Small-molecule JNK inhibitors could be valuable tools to study the therapeutic benefits of inhibiting these enzymes and as leads for potential drugs targeting JNKs. In this report, we disclose a series of potent and highly selective JNK inhibitors with good pharmacokinetic profiles.
Subject(s)
Amides/chemical synthesis , JNK Mitogen-Activated Protein Kinases/antagonists & inhibitors , Pyridines/chemical synthesis , Administration, Oral , Amides/pharmacokinetics , Amides/pharmacology , Animals , Biological Availability , Crystallography, X-Ray , Humans , In Vitro Techniques , Mice , Microsomes/metabolism , Models, Molecular , Pyridines/pharmacokinetics , Pyridines/pharmacology , Rats , Structure-Activity Relationship , ThermodynamicsABSTRACT
The discovery and pharmacological evaluation of potent, selective, and orally bioavailable growth hormone secretagogue receptor (GHS-R) antagonists are reported. Previously, 2,4-diaminopyrimidine-based GHS-R antagonists reported from our laboratories have been shown to be dihydrofolate reductase (DHFR) inhibitors. By comparing the X-ray crystal structure of DHFR docked with our GHS-R antagonists and GHS-R modeling, we designed and synthesized a series of potent and DHFR selective GHS-R antagonists with good pharmacokinetic (PK) profiles. An amide derivative 13d (Ca2+ flux IC50 = 188 nM, [brain]/[plasma] = 0.97 @ 8 h in rat) showed a 10% decrease in 24 h food intake in rats, and over 5% body weight reduction after 14-day oral treatment in diet-induced obese (DIO) mice. In comparison, a urea derivative 14c (Ca2+ flux IC50 = 7 nM, [brain]/[plasma] = 0.0 in DIO) failed to show significant effect on food intake in the acute feeding DIO model. These observations demonstrated for the first time that peripheral GHS-R blockage with small molecule GHS-R antagonists might not be sufficient for suppressing appetite and inducing body weight reduction.
Subject(s)
Aminopyridines/chemical synthesis , Anti-Obesity Agents/chemical synthesis , Receptors, G-Protein-Coupled/antagonists & inhibitors , Administration, Oral , Amides/chemical synthesis , Amides/pharmacology , Aminopyridines/pharmacology , Animals , Anti-Obesity Agents/pharmacology , Appetite Depressants/chemical synthesis , Appetite Depressants/pharmacology , Biological Availability , Body Weight/drug effects , Cell Line , Crystallography, X-Ray , Eating/drug effects , Humans , Male , Mice , Mice, Inbred C57BL , Mice, Obese , Models, Molecular , Molecular Structure , Rats , Rats, Sprague-Dawley , Receptors, Ghrelin , Structure-Activity Relationship , Urea/analogs & derivatives , Urea/chemical synthesis , Urea/pharmacologyABSTRACT
The c-Jun N-terminal kinases (JNK-1, -2, and -3) are members of the mitogen activated protein (MAP) kinase family of enzymes. They are activated in response to certain cytokines, as well as by cellular stresses including chemotoxins, peroxides, and irradiation. They have been implicated in the pathology of a variety of different diseases with an inflammatory component including asthma, stroke, Alzheimer's disease, and type 2 diabetes mellitus. In this work, high-throughput screening identified a JNK inhibitor with an excellent kinase selectivity profile. Using X-ray crystallography and biochemical screening to guide our lead optimization, we prepared compounds with inhibitory potencies in the low-double-digit nanomolar range, activity in whole cells, and pharmacokinetics suitable for in vivo use. The new compounds were over 1,000-fold selective for JNK-1 and -2 over other MAP kinases including ERK2, p38alpha, and p38delta and showed little inhibitory activity against a panel of 74 kinases.
Subject(s)
Aminopyridines/chemical synthesis , Mitogen-Activated Protein Kinase 8/antagonists & inhibitors , Mitogen-Activated Protein Kinase 9/antagonists & inhibitors , Aminopyridines/chemistry , Aminopyridines/pharmacology , Animals , Biological Availability , Cell Line, Tumor , Crystallography, X-Ray , Half-Life , Humans , Mitogen-Activated Protein Kinase 10/metabolism , Mitogen-Activated Protein Kinase 8/chemistry , Mitogen-Activated Protein Kinase 8/metabolism , Mitogen-Activated Protein Kinase 9/metabolism , Models, Molecular , Phosphorylation , Protein Conformation , Rats , Rats, Sprague-DawleyABSTRACT
Ghrelin, a gut-derived orexigenic hormone, is an endogenous ligand of the growth hormone secretagogue receptor (GHS-R). Centrally administered ghrelin has been shown to cause hunger and increase food intake in rodents. Inhibition of ghrelin actions with ghrelin antibody, peptidyl GHS-R antagonists, and antisense oligonucleosides resulted in weight loss and food intake decrease in rodents. Here we report the effects of GHS-R antagonists, some of which were potent, selective, and orally bioavailable. A structure-activity relationship study led to the discovery of 8a, which was effective in decreasing food intake and body weight in several acute rat studies.
Subject(s)
Pyrimidines/pharmacology , Receptors, G-Protein-Coupled/antagonists & inhibitors , Animals , CHO Cells , Cricetinae , Drug Evaluation, Preclinical , Humans , Ligands , Molecular Structure , Pyrimidines/chemical synthesis , Pyrimidines/chemistry , Receptors, Ghrelin , Stereoisomerism , Structure-Activity Relationship , Time FactorsABSTRACT
The synthesis and structure-activity relationships of the 4- and 6-substituents of 2,4-diaminopyrimidine-based growth hormone secretagogue receptor (GHS-R) antagonists are described. Diaminopyrimidines with 6-norbornenyl (4n) and 6-tetrahydrofuranyl (4p) substitutents were found to exhibit potent GHS-R antagonism and good selectivity (approximately 1000-fold) against dihydrofolate reductase.
