RESUMO
Attempts to optimize pharmacokinetic properties in a promising series of pyrrolopyrimidinone MARK inhibitors for the treatment of Alzheimer's disease are described. A focus on physical properties and ligand efficiency while prosecuting this series afforded key tool compounds that revealed a large discrepancy in the rat in vitro-in vivo DMPK (Drug Metabolism/Pharmacokinetics) correlation. These differences prompted an in vivo rat disposition study employing a radiolabeled representative of the series, and the results from this experiment justified the termination of any further optimization efforts.
Assuntos
Doença de Alzheimer/tratamento farmacológico , Inibidores de Proteínas Quinases/farmacologia , Pirimidinonas/farmacologia , Pirróis/farmacologia , Doença de Alzheimer/metabolismo , Animais , Relação Dose-Resposta a Droga , Humanos , Isoenzimas/antagonistas & inibidores , Isoenzimas/metabolismo , Estrutura Molecular , Inibidores de Proteínas Quinases/química , Inibidores de Proteínas Quinases/metabolismo , Proteínas Serina-Treonina Quinases/antagonistas & inibidores , Proteínas Serina-Treonina Quinases/metabolismo , Pirimidinonas/química , Pirimidinonas/metabolismo , Pirróis/química , Pirróis/metabolismo , Ratos , Relação Estrutura-AtividadeRESUMO
The initial structure activity relationships around an isoindoline uHTS hit will be described. Information gleaned from ligand co-crystal structures allowed for rapid refinements in both MARK potency and kinase selectivity. These efforts allowed for the identification of a compound with properties suitable for use as an in vitro tool compound for validation studies on MARK as a viable target for Alzheimer's disease.
Assuntos
Desenho de Fármacos , Inibidores de Proteínas Quinases/farmacologia , Pirimidinonas/farmacologia , Pirróis/farmacologia , Doença de Alzheimer/tratamento farmacológico , Doença de Alzheimer/metabolismo , Linhagem Celular , Cristalografia por Raios X , Relação Dose-Resposta a Droga , Humanos , Modelos Moleculares , Estrutura Molecular , Inibidores de Proteínas Quinases/síntese química , Inibidores de Proteínas Quinases/química , Proteínas Serina-Treonina Quinases/antagonistas & inibidores , Proteínas Serina-Treonina Quinases/metabolismo , Pirimidinonas/síntese química , Pirimidinonas/química , Pirróis/síntese química , Pirróis/química , Relação Estrutura-AtividadeRESUMO
The design, synthesis, and binding activity of ring constrained analogs of the acyclic cannabinoid-1 receptor (CB1R) inverse agonist taranabant 1 are described. The initial inspiration for these taranabant derivatives was its conformation 1a, determined by (1)H NMR, X-ray, and molecular modeling. The constrained analogs were all much less potent than their acyclic parent structure. The results obtained are discussed in the context of a predicted binding of 1 to a homology model of CB1R.
Assuntos
Amidas/química , Fármacos Antiobesidade/síntese química , Piridinas/química , Receptor CB1 de Canabinoide/química , Amidas/síntese química , Amidas/farmacologia , Fármacos Antiobesidade/química , Fármacos Antiobesidade/farmacologia , Simulação por Computador , Humanos , Modelos Moleculares , Conformação Molecular , Ligação Proteica , Piridinas/síntese química , Piridinas/farmacologia , Receptor CB1 de Canabinoide/metabolismoRESUMO
Obesity is a chronic medical condition that is affecting large population throughout the world. CB1 as a target for treatment of obesity has been under intensive studies. Taranabant was discovered and then developed by Merck as the 1st generation CB1R inverse agonist. Reported here is part of our effort on the 2nd generation of CB1R inverse agonist from the acyclic amide scaffold. We replaced the oxygen linker in taranabant with nitrogen and prepared a series of amino heterocyclic analogs through a divergent synthesis. Although in general, the amine linker gave reduced binding affinity, potent and selective CB1R inverse agonist was identified from the amino heterocycle series. Molecular modeling was applied to study the binding of the amino heterocycle series at CB1 binding site. The in vitro metabolism of representative members was studied and only trace glucuronidation was found. Thus, it suggests that the right hand side of the molecule may not be the appropriate site for glucuronidation.
Assuntos
Amidas/química , Fármacos Antiobesidade/química , Piridinas/química , Receptor CB1 de Canabinoide/antagonistas & inibidores , Amidas/síntese química , Amidas/farmacologia , Animais , Fármacos Antiobesidade/síntese química , Fármacos Antiobesidade/farmacologia , Sítios de Ligação , Simulação por Computador , Agonismo Inverso de Drogas , Humanos , Microssomos Hepáticos/metabolismo , Piridinas/farmacologia , Ratos , Receptor CB1 de Canabinoide/metabolismo , Receptor CB2 de Canabinoide/agonistas , Receptor CB2 de Canabinoide/metabolismo , Proteínas Recombinantes/agonistas , Proteínas Recombinantes/metabolismoRESUMO
The discovery of a structurally distinct cannabinoid-1 receptor (CB1R) positron emission tomography tracer is described. Starting from an acyclic amide CB1R inverse agonist (1) as the lead compound, an efficient route to introduce 18F to the molecule was developed. Further optimization focused on reducing the lipophilicity and increasing the CB1R affinity. These efforts led to the identification of [18F]-16 that exhibited good brain uptake and an excellent signal-to-noise ratio in rhesus monkeys.
Assuntos
Amidas/síntese química , Radioisótopos de Flúor , Piridinas/síntese química , Compostos Radiofarmacêuticos/síntese química , Receptor CB1 de Canabinoide/metabolismo , Amidas/química , Amidas/farmacocinética , Animais , Encéfalo/diagnóstico por imagem , Encéfalo/metabolismo , Células CHO , Cricetinae , Cricetulus , Humanos , Macaca mulatta , Tomografia por Emissão de Pósitrons , Piridinas/química , Piridinas/farmacocinética , Ensaio Radioligante , Compostos Radiofarmacêuticos/química , Compostos Radiofarmacêuticos/farmacocinética , Receptor CB1 de Canabinoide/agonistas , Receptor CB1 de Canabinoide/antagonistas & inibidores , Proteínas Recombinantes/metabolismo , Relação Estrutura-AtividadeRESUMO
The discovery of novel acyclic amide cannabinoid-1 receptor inverse agonists is described. They are potent, selective, orally bioavailable, and active in rodent models of food intake and body weight reduction. A major focus of the optimization process was to increase in vivo efficacy and to reduce the potential for formation of reactive metabolites. These efforts led to the identification of compound 48 for development as a clinical candidate for the treatment of obesity.
Assuntos
Fármacos Antiobesidade/farmacologia , Canabinoides/farmacologia , Obesidade/tratamento farmacológico , Receptor CB1 de Canabinoide/agonistas , Receptor CB2 de Canabinoide/agonistas , Animais , Fármacos Antiobesidade/síntese química , Fármacos Antiobesidade/química , Peso Corporal/efeitos dos fármacos , Canabinoides/síntese química , Canabinoides/química , AMP Cíclico/metabolismo , Ingestão de Alimentos/efeitos dos fármacos , Humanos , Fígado/efeitos dos fármacos , Fígado/metabolismo , Microssomos/efeitos dos fármacos , Microssomos/metabolismo , Ratos , Receptor CB1 de Canabinoide/antagonistas & inibidores , Receptor CB1 de Canabinoide/metabolismo , Receptor CB2 de Canabinoide/antagonistas & inibidores , Receptor CB2 de Canabinoide/metabolismoRESUMO
Metabolic activation of drug candidates to electrophilic reactive metabolites that can covalently modify cellular macromolecules may result in acute and/or idiosyncratic immune system-mediated toxicities in humans. This presents a significant potential liability for the future development of these compounds as safe therapeutic agents. We present here an example of an approach where sites of metabolic activation within a new drug candidate series were rapidly identified using online liquid chromatography/multi-stage mass spectrometry on an ion trap mass spectrometer. This was accomplished by trapping the reactive intermediates formed upon incubation of compounds with rat and human liver microsomes as their corresponding glutathione conjugates and mass spectral characterization of these thiol adducts. Based on the structures of the GSH adducts identified, potential sites and mechanisms of bioactivation within the chemical structure were proposed. These metabolism studies were interfaced with iterative structural modifications of the chemical series in order to block these bioactivation sites within the molecule. This strategy led to a significant reduction in the propensity of the compounds to undergo metabolic activation as evidenced by reductions in the irreversible binding of radioactivity to liver microsomal material upon incubation of tritium-labeled compounds with this in vitro system. With the efficiency and throughput achievable with such an approach, it appears feasible to identify and address the metabolic activation potential of new drug leads during routine metabolite identification studies in an early drug discovery setting.
Assuntos
Drogas em Investigação/farmacocinética , Espectrometria de Massas por Ionização por Electrospray , Animais , Biotransformação , Drogas em Investigação/análise , Glutationa/metabolismo , Humanos , Masculino , Microssomos Hepáticos/efeitos dos fármacos , Microssomos Hepáticos/metabolismo , Ratos , Ratos Sprague-Dawley , Relação Estrutura-Atividade , TrítioRESUMO
c-Met is a transmembrane tyrosine kinase that mediates activation of several signaling pathways implicated in aggressive cancer phenotypes. In recent years, research into this area has highlighted c-Met as an attractive cancer drug target, triggering a number of approaches to disrupt aberrant c-Met signaling. Screening efforts identified a unique class of 5H-benzo[4,5]cyclohepta[1,2-b]pyridin-5-one kinase inhibitors, exemplified by 1. Subsequent SAR studies led to the development of 81 (MK-2461), a potent inhibitor of c-Met that was efficacious in preclinical animal models of tumor suppression. In addition, biochemical studies and X-ray analysis have revealed that this unique class of kinase inhibitors binds preferentially to the activated (phosphorylated) form of the kinase. This report details the development of 81 and provides a description of its unique biochemical properties.
Assuntos
Antineoplásicos/síntese química , Benzocicloeptenos/síntese química , Piridinas/síntese química , Receptores Proteína Tirosina Quinases/antagonistas & inibidores , Animais , Antineoplásicos/farmacocinética , Antineoplásicos/farmacologia , Benzocicloeptenos/farmacocinética , Benzocicloeptenos/farmacologia , Linhagem Celular Tumoral , Cristalografia por Raios X , Cães , Ensaios de Seleção de Medicamentos Antitumorais , Feminino , Haplorrinos , Humanos , Camundongos , Camundongos Nus , Modelos Moleculares , Mutação , Transplante de Neoplasias , Fosforilação , Ligação Proteica , Pirazóis/síntese química , Pirazóis/farmacocinética , Pirazóis/farmacologia , Piridinas/farmacocinética , Piridinas/farmacologia , Ratos , Receptores Proteína Tirosina Quinases/genética , Relação Estrutura-Atividade , Sulfonamidas/síntese química , Sulfonamidas/farmacocinética , Sulfonamidas/farmacologia , Transplante HeterólogoRESUMO
We report the development and characterization of compound 22 (MK-5046), a potent, selective small molecule agonist of BRS-3 (bombesin receptor subtype-3). In pharmacological testing using diet-induced obese mice, compound 22 caused mechanism-based, dose-dependent reductions in food intake and body weight.
RESUMO
The receptor tyrosine kinase c-Met is an attractive target for therapeutic blockade in cancer. Here, we describe MK-2461, a novel ATP-competitive multitargeted inhibitor of activated c-Met. MK-2461 inhibited in vitro phosphorylation of a peptide substrate recognized by wild-type or oncogenic c-Met kinases (N1100Y, Y1230C, Y1230H, Y1235D, and M1250T) with IC(50) values of 0.4 to 2.5 nmol/L. In contrast, MK-2461 was several hundredfold less potent as an inhibitor of c-Met autophosphorylation at the kinase activation loop. In tumor cells, MK-2461 effectively suppressed constitutive or ligand-induced phosphorylation of the juxtamembrane domain and COOH-terminal docking site of c-Met, and its downstream signaling to the phosphoinositide 3-kinase-AKT and Ras-extracellular signal-regulated kinase pathways, without inhibiting autophosphorylation of the c-Met activation loop. BIAcore studies indicated 6-fold tighter binding to c-Met when it was phosphorylated, suggesting that MK-2461 binds preferentially to activated c-Met. MK-2461 displayed significant inhibitory activities against fibroblast growth factor receptor (FGFR), platelet-derived growth factor receptor, and other receptor tyrosine kinases. In cell culture, MK-2461 inhibited hepatocyte growth factor/c-Met-dependent mitogenesis, migration, cell scatter, and tubulogenesis. Seven of 10 MK-2461-sensitive tumor cell lines identified from a large panel harbored genomic amplification of MET or FGFR2. In a murine xenograft model of c-Met-dependent gastric cancer, a well-tolerated oral regimen of MK-2461 administered at 100 mg/kg twice daily effectively suppressed c-Met signaling and tumor growth. Similarly, MK-2461 inhibited the growth of tumors formed by s.c. injection of mouse NIH-3T3 cells expressing oncogenic c-Met mutants. Taken together, our findings support further preclinical development of MK-2461 for cancer therapy.
Assuntos
Antineoplásicos/farmacologia , Sistemas de Liberação de Medicamentos , Inibidores de Proteínas Quinases/farmacologia , Proteínas Proto-Oncogênicas c-met/antagonistas & inibidores , Animais , Antineoplásicos/administração & dosagem , Antineoplásicos/uso terapêutico , Células Cultivadas , Cães , Sistemas de Liberação de Medicamentos/métodos , Ativação Enzimática/efeitos dos fármacos , Feminino , Haplorrinos , Humanos , Camundongos , Camundongos Nus , Células NIH 3T3 , Neoplasias/tratamento farmacológico , Neoplasias/metabolismo , Inibidores de Proteínas Quinases/administração & dosagem , Inibidores de Proteínas Quinases/uso terapêutico , Proteínas Proto-Oncogênicas c-met/metabolismo , Especificidade por Substrato/efeitos dos fármacos , Ensaios Antitumorais Modelo de XenoenxertoRESUMO
Extremely potent very late antigen-4 (VLA-4) antagonists with picomolar, whole blood activity and slow dissociation rates were discovered by incorporating an amino substituent on the proline fragment of the initial lead structure. This level of potency against the unactivated form of VLA-4 was shown to be sufficient to overcome the poor pharmacokinetic profiles typical of this class of VLA-4 antagonists, and sustained activity as measured by receptor occupancy was achieved in preclinical species after oral dosing.
Assuntos
Integrina alfa4beta1/antagonistas & inibidores , Niacinamida/análogos & derivados , Fenilalanina/análogos & derivados , Administração Oral , Animais , Citocromo P-450 CYP3A , Inibidores do Citocromo P-450 CYP3A , Cães , Humanos , Concentração Inibidora 50 , Niacinamida/síntese química , Niacinamida/farmacocinética , Niacinamida/farmacologia , Fenilalanina/administração & dosagem , Fenilalanina/síntese química , Fenilalanina/farmacocinética , Fenilalanina/farmacologia , RatosRESUMO
Through alternative splicing, the human cannabinoid CB(1) receptor gene encodes three variants of protein products (hCB(1), hCB(1a), and hCB(1b)) that differ in amino acid sequence at the N terminus of the receptors. By semi-quantitative PCR from human adult and fetal brain mRNA, we demonstrated that the transcript encoding hCB(1) is the major transcript, and estimated that those of hCB(1a) and hCB(1b) represent fewer than 5% of the total human cannabinoid CB(1) receptor transcripts. We characterized the three variants stably expressed in CHO cells. In the contrary to the study by Ryberg et al. (FEBS Lett 579[1], 259-64), we did not find substantial difference among the three variants according to the binding affinity, functional potency, and efficacy of meth-anandamide, 2-arachidonoyl glycerol, virodhamine, Noladin ether, docosatetraenylethanolamide, CP55940, AM251, and compound 35e (an acyclic class human CB(1) receptor inverse agonist similar to MK-0364). The functional significance of different human cannabinoid CB(1) receptor variants remains to be clarified.
Assuntos
Encéfalo/metabolismo , Receptor CB1 de Canabinoide/metabolismo , Processamento Alternativo , Animais , Células CHO , Cricetinae , Cricetulus , Humanos , Técnicas In Vitro , Reação em Cadeia da Polimerase , RNA Mensageiro/análise , Receptor CB1 de Canabinoide/genéticaRESUMO
Sulfonamide analogues of the potent CB1R inverse agonist taranabant were prepared and optimized for potency and selectivity for CB1R. They were variably more potent than the corresponding amide analogues. The most potent representative 22 had good pharmacokinetic and brain levels, but was modestly active in blocking CB1R agonist-mediated hypothermia.
Assuntos
Moduladores de Receptores de Canabinoides/síntese química , Receptor CB1 de Canabinoide/efeitos dos fármacos , Sulfonamidas/síntese química , Animais , Fármacos Antiobesidade/síntese química , Fármacos Antiobesidade/farmacologia , Química Encefálica , Moduladores de Receptores de Canabinoides/farmacologia , Humanos , Hipotermia/tratamento farmacológico , Concentração Inibidora 50 , Farmacocinética , Ratos , Receptor CB1 de Canabinoide/agonistas , Relação Estrutura-Atividade , Sulfonamidas/farmacologiaRESUMO
The cannabinoid-1 receptor (CB1R) has been implicated in the control of energy balance. To explore the pharmacological utility of CB1R inhibition for the treatment of obesity, we evaluated the efficacy of N-[(1S,2S)-3-(4-chlorophenyl)-2-(3-cyanophenyl)-1-methylpropyl]-2-methyl-2-[[5-(trifluoromethyl)pyridin-2-yl]oxy]propanamide (MK-0364) and determined the relationship between efficacy and brain CB1R occupancy in rodents. MK-0364 was shown to be a highly potent CB1R inverse agonist that inhibited the binding and functional activity of various agonists with a binding K(i) of 0.13 nM for the human CB1R in vitro. MK-0364 dose-dependently inhibited food intake and weight gain, with an acute minimum effective dose of 1 mg/kg in diet-induced obese (DIO) rats. CB1R mechanism-based effect was demonstrated for MK-0364 by its lack of efficacy in CB1R-deficient mice. Chronic treatment of DIO rats with MK-0364 dose-dependently led to significant weight loss with a minimum effective dose of 0.3 mg/kg (p.o.), or a plasma C(max) of 87 nM. Weight loss was accompanied by the loss of fat mass. Partial occupancy (30-40%) of brain CB1R by MK-0364 was sufficient to reduce body weight. The magnitude of weight loss was correlated with brain CB1R occupancy. The partial receptor occupancy requirement for efficacy was also consistent with the reduced food intake of the heterozygous mice carrying one disrupted allele of CB1R gene compared with the wild-type mice. These studies demonstrated that MK-0364 is a highly potent and selective CB1R inverse agonist and that it is orally active in rodent models of obesity.
Assuntos
Amidas/farmacologia , Fármacos Antiobesidade/farmacologia , Obesidade/tratamento farmacológico , Piridinas/farmacologia , Receptor CB1 de Canabinoide/metabolismo , Amidas/química , Amidas/metabolismo , Animais , Fármacos Antiobesidade/química , Fármacos Antiobesidade/metabolismo , Ligação Competitiva/efeitos dos fármacos , Temperatura Corporal/efeitos dos fármacos , Peso Corporal/efeitos dos fármacos , Células CHO , Colforsina/farmacologia , Cricetinae , Cricetulus , AMP Cíclico/metabolismo , Cicloexanóis/farmacologia , Relação Dose-Resposta a Droga , Ingestão de Alimentos/efeitos dos fármacos , Humanos , Indóis/metabolismo , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Estrutura Molecular , Obesidade/metabolismo , Obesidade/fisiopatologia , Piperidinas/metabolismo , Piridinas/química , Piridinas/metabolismo , Ratos , Ratos Sprague-Dawley , Receptor CB1 de Canabinoide/genética , Receptor CB1 de Canabinoide/fisiologia , TransfecçãoRESUMO
[(18)F]MK-9470 is a selective, high-affinity, inverse agonist (human IC(50), 0.7 nM) for the cannabinoid CB1 receptor (CB1R) that has been developed for use in human brain imaging. Autoradiographic studies in rhesus monkey brain showed that [(18)F]MK-9470 binding is aligned with the reported distribution of CB1 receptors with high specific binding in the cerebral cortex, cerebellum, caudate/putamen, globus pallidus, substantia nigra, and hippocampus. Positron emission tomography (PET) imaging studies in rhesus monkeys showed high brain uptake and a distribution pattern generally consistent with that seen in the autoradiographic studies. Uptake was blocked by pretreatment with a potent CB1 inverse agonist, MK-0364. The ratio of total to nonspecific binding in putamen was 4-5:1, indicative of a strong specific signal that was confirmed to be reversible via displacement studies with MK-0364. Baseline PET imaging studies in human research subject demonstrated behavior of [(18)F]MK-9470 very similar to that seen in monkeys, with very good test-retest variability (7%). Proof of concept studies in healthy young male human subjects showed that MK-0364, given orally, produced a dose-related reduction in [(18)F]MK-9470 binding reflecting CB1R receptor occupancy by the drug. Thus, [(18)F]MK-9470 has the potential to be a valuable, noninvasive research tool for the in vivo study of CB1R biology and pharmacology in a variety of neuropsychiatric disorders in humans. In addition, it allows demonstration of target engagement and noninvasive dose-occupancy studies to aid in dose selection for clinical trials of CB1R inverse agonists.