RESUMEN
Highly selective orexin receptor antagonists (SORAs) of the orexin 2 receptor (OX2R) have become attractive targets both as potential therapeutics for insomnia as well as biological tools to help further elucidate the underlying pharmacology of the orexin signaling pathway. Herein, we describe the discovery of a novel piperidine ether 2-SORA class identified by systematic lead optimization beginning with filorexant, a dual orexin receptor antagonist (DORA) that recently completed Phase 2 clinical trials. Changes to the ether linkage and pendant heterocycle of filorexant were found to impart significant selectivity for OX2R, culminating in lead compound PE-6. PE-6 displays sub-nanomolar binding affinity and functional potency on OX2R while maintaining >1600-fold binding selectivity and >200-fold functional selectivity versus the orexin 1 receptor (OX1R). PE-6 bears a clean off-target profile, a good overall preclinical pharmacokinetic (PK) profile, and reduces wakefulness with increased NREM and REM sleep when evaluated in vivo in a rat sleep study. Importantly, subtle structural changes to the piperidine ether class impart dramatic changes in receptor selectivity. To this end, our laboratories have identified multiple piperidine ether 2-SORAs, 1-SORAs, and DORAs, providing access to a number of important biological tool compounds from a single structural class.
Asunto(s)
Éteres/química , Antagonistas de los Receptores de Orexina , Piperidinas/química , Pirimidinas/química , Animales , Perros , Evaluación Preclínica de Medicamentos , Éteres/síntesis química , Éteres/farmacocinética , Semivida , Humanos , Receptores de Orexina/metabolismo , Piperidinas/metabolismo , Unión Proteica , Pirimidinas/metabolismo , Ratas , Sueño/efectos de los fármacos , Relación Estructura-ActividadRESUMEN
Dual Orexin Receptor Antagonists (DORA) bind to both the Orexin 1 and 2 receptors. High resolution crystal structures of the Orexin 1 and 2 receptors, both class A GPCRs, were not available at the time of this study, and thus, ligand-based analyses were invoked and successfully applied to the design of DORAs. Computational analysis, ligand based superposition, unbound small-molecule X-ray crystal structures and NMR analysis were utilized to understand the conformational preferences of key DORAs and excellent agreement between these orthogonal approaches was seen in the majority of compounds examined. The predominantly face-to-face (F2F) interaction observed between the distal aromatic rings was the core 3D shape motif in our design principle and was used in the development of compounds. A notable exception, however, was seen between computation and experiment for suvorexant where the molecule exhibits an extended conformation in the unbound small-molecule X-ray structure. Even taking into account solvation effects explicitly in our calculations, we nevertheless find support that the F2F conformation is the bioactive conformation. Using a dominant states approximation for the partition function, we made a comprehensive assessment of the free energies required to adopt both an extended and a F2F conformation of a number of DORAs. Interestingly, we find that only a F2F conformation is consistent with the activities reported.
Asunto(s)
Azepinas/química , Cristalografía por Rayos X , Receptores de Orexina/química , Triazoles/química , Humanos , Ligandos , Espectroscopía de Resonancia Magnética , Conformación Molecular , Estructura Molecular , Antagonistas de los Receptores de OrexinaRESUMEN
Herein we describe the discovery of a 2-aminopyridine scaffold as a potent and isoform selective inhibitor of the Nav1.8 sodium channel. Parallel library synthesis, guided by in silico predictions, rapidly transformed initial hits into a novel 2-aminopyridine lead class possessing good ADME and pharmacokinetic profiles that were able to display activity in a clinically translatable nonhuman primate capsaicin-sensitized thermode pharmacodynamic assay. Progress toward the lead identification, optimization, and in vivo efficacy of these compounds will be discussed.
RESUMEN
Inhibition of glucosylceramide synthase (GCS) has been proposed as a therapeutic strategy for the treatment of Parkinson's Disease (PD), particularly in patients where glycosphingolipid accumulation and lysosomal impairment are thought to be contributing to disease progression. Herein, we report the late-stage optimization of an orally bioavailable and CNS penetrant isoindolinone class of GCS inhibitors. Starting from advanced lead 1, we describe efforts to identify an improved compound with a lower human dose projection, minimal P-glycoprotein (P-gp) efflux, and acceptable pregnane X receptor (PXR) profile through fluorine substitution. Our strategy involved the use of predicted volume ligand efficiency to advance compounds with greater potential for low human doses down our screening funnel. We also applied minimized electrostatic potentials (Vmin) calculations for hydrogen bond acceptor sites to rationalize P-gp SAR. Together, our strategies enabled the alignment of a lower human dose with reduced P-gp efflux, and favorable PXR selectivity for the discovery of compound 12.
RESUMEN
We describe the discovery of potent and orally bioavailable tetrahydropyridopyrimidine inhibitors of phosphodiesterase 10A by systematic optimization of a novel HTS lead. Lead compound THPP-1 exhibits nanomolar potencies, excellent pharmacokinetic properties, and a clean off-target profile. It displays in vivo target engagement as measured by increased rat striatal cGMP levels upon oral dosing. It shows dose-dependent efficacy in a key pharmacodynamic assay predictive of antipsychotic activity, the psychostimulant-induced rat hyperlocomotion assay. Further, THPP-1 displays significantly fewer preclinical adverse events in assays measuring prolactin secretion, catalepsy, and weight gain, in contrast to the typical and atypical antipsychotics haloperidol and olanzapine.
Asunto(s)
Descubrimiento de Drogas , Inhibidores de Fosfodiesterasa/uso terapéutico , Piridinas/farmacología , Pirimidinas/farmacología , Esquizofrenia/tratamiento farmacológico , Administración Oral , Animales , GMP Cíclico/análisis , Relación Dosis-Respuesta a Droga , Humanos , Estructura Molecular , Inhibidores de Fosfodiesterasa/administración & dosificación , Inhibidores de Fosfodiesterasa/química , Hidrolasas Diéster Fosfóricas/metabolismo , Piridinas/administración & dosificación , Piridinas/química , Pirimidinas/administración & dosificación , Pirimidinas/química , Ratas , Relación Estructura-ActividadRESUMEN
Orexins/hypocretins are key neuropeptides responsible for regulating central arousal and reward circuits. Two receptors respond to orexin signaling, orexin 1 receptor (OX(1)R) and orexin 2 receptor (OX(2)R) with partially overlapping nervous system distributions. Genetic studies suggest orexin receptor antagonists could be therapeutic for insomnia and other disorders with disruptions of sleep and wake. Suvorexant (MK-4305) is a potent, selective, and orally bioavailable antagonist of OX(1)R and OX(2)R currently under clinical investigation as a novel therapy for insomnia. Examination of Suvorexant in radioligand binding assays using tissue from transgenic rats expressing the human OX(2)R found nearly full receptor occupancy (>90%) at plasma exposures of 1.1 µM. Dosed orally Suvorexant significantly and dose-dependently reduced locomotor activity and promoted sleep in rats (10, 30, and 100 mg/kg), dogs (1 and 3 mg/kg), and rhesus monkeys (10 mg/kg). Consistent cross-species sleep/wake architecture changes produced by Suvorexant highlight a unique opportunity to develop dual orexin antagonists as a novel therapy for insomnia.
Asunto(s)
Azepinas/farmacología , Receptores Acoplados a Proteínas G/antagonistas & inhibidores , Receptores de Neuropéptido/antagonistas & inhibidores , Sueño/efectos de los fármacos , Triazoles/farmacología , Animales , Área Bajo la Curva , Azidas , Células CHO , Cricetinae , Cricetulus , Relación Dosis-Respuesta a Droga , Electrocardiografía , Electromiografía , Humanos , Macaca mulatta , Actividad Motora/efectos de los fármacos , Octreótido/análogos & derivados , Receptores de Orexina , Unión Proteica/efectos de los fármacos , Ratas , Tiempo de Reacción/efectos de los fármacos , Receptores Acoplados a Proteínas G/genética , Receptores Acoplados a Proteínas G/metabolismo , Receptores de Neuropéptido/genética , Receptores de Neuropéptido/metabolismo , TransfecciónRESUMEN
Narcolepsy type 1 (NT1) is a chronic neurological disorder that impairs the brain's ability to control sleep-wake cycles. Current therapies are limited to the management of symptoms with modest effectiveness and substantial adverse effects. Agonists of the orexin receptor 2 (OX2R) have shown promise as novel therapeutics that directly target the pathophysiology of the disease. However, identification of drug-like OX2R agonists has proven difficult. Here we report cryo-electron microscopy structures of active-state OX2R bound to an endogenous peptide agonist and a small-molecule agonist. The extended carboxy-terminal segment of the peptide reaches into the core of OX2R to stabilize an active conformation, while the small-molecule agonist binds deep inside the orthosteric pocket, making similar key interactions. Comparison with antagonist-bound OX2R suggests a molecular mechanism that rationalizes both receptor activation and inhibition. Our results enable structure-based discovery of therapeutic orexin agonists for the treatment of NT1 and other hypersomnia disorders.
Asunto(s)
Aminopiridinas/química , Azepinas/química , Antagonistas de los Receptores de Orexina/química , Receptores de Orexina/química , Péptidos/química , Fármacos Inductores del Sueño/química , Sulfonamidas/química , Triazoles/química , Aminopiridinas/metabolismo , Azepinas/metabolismo , Sitios de Unión , Clonación Molecular , Microscopía por Crioelectrón , Escherichia coli/genética , Escherichia coli/metabolismo , Expresión Génica , Vectores Genéticos/química , Vectores Genéticos/metabolismo , Células HEK293 , Humanos , Simulación de Dinámica Molecular , Antagonistas de los Receptores de Orexina/metabolismo , Receptores de Orexina/agonistas , Receptores de Orexina/metabolismo , Péptidos/metabolismo , Unión Proteica , Conformación Proteica en Hélice alfa , Conformación Proteica en Lámina beta , Dominios y Motivos de Interacción de Proteínas , Proteínas Recombinantes/química , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo , Fármacos Inductores del Sueño/metabolismo , Sulfonamidas/metabolismo , Triazoles/metabolismoRESUMEN
3(S)-(6-methoxypyridin-3-yl)-3-[2-oxo-3-[3-(5,6,7,8-tetrahydro-[1,8]-naphthyridin-2-yl)propyl]imidazolidin-1-yl]propionic acid 6 was identified as a potent and selective antagonist of the alpha(v)beta(3) receptor. This compound has an excellent in vitro profile (IC(50) = 0.08 nM), a significant unbound fraction in human plasma (12%), and good pharmacokinetics in rat, dog, and rhesus monkey. On the basis of the efficacy shown in three in vivo models of bone turnover, the compound was selected for clinical development. To support the ongoing metabolism and safety studies, a novel strategy was employed in which a series of oxidized derivatives of 6 were prepared by exposure of 6 (or the methyl ester) to chemical oxidizing agents. These products proved useful in the identification of active metabolites generated by either in vitro or in vivo metabolism.
Asunto(s)
Integrina alfaVbeta3/antagonistas & inhibidores , Naftiridinas/síntesis química , Osteoporosis , Propionatos/síntesis química , Animales , Densidad Ósea/efectos de los fármacos , Resorción Ósea/tratamiento farmacológico , Resorción Ósea/etiología , Resorción Ósea/metabolismo , Perros , Femenino , Humanos , Macaca mulatta , Masculino , Naftiridinas/química , Naftiridinas/farmacología , Osteoporosis/tratamiento farmacológico , Osteoporosis/prevención & control , Ovariectomía , Oxidación-Reducción , Propionatos/química , Propionatos/farmacología , Ratas , Ratas Sprague-Dawley , Estereoisomerismo , Relación Estructura-ActividadRESUMEN
Phosphodiesterase 10A (PDE10A) is a novel target for the treatment of schizophrenia that may address multiple symptomatic domains associated with this disorder. PDE10A is highly expressed in the brain and functions to metabolically inactivate the important second messengers cAMP and cGMP. Here we describe effects of a potent and orally bioavailable PDE10A inhibitor [2-(6-chloropyridin-3-yl)-4-(2-methoxyethoxy)-7,8-dihydropyrido[4,3-d]pyrimidin-6(5H)-yl](imidazo[1,5-a]pyridin-1-yl)methanone] (THPP-1) on striatal signaling pathways, in behavioral tests that predict antipsychotic potential, and assays that measure episodic-like memory in rat and executive function in rhesus monkey. THPP-1 exhibits nanomolar potency on the PDE10A enzyme, demonstrates excellent pharmacokinetic properties in multiple preclinical animal species, and is selective for PDE10A over other PDE families of enzymes. THPP-1 significantly increased phosphorylation of proteins in the striatum involved in synaptic plasticity, including the a-amino-3-hydroxy-5-methylisoxazole-4-proprionic acid receptor (AMPA) GluR1 subunit, extracellular receptor kinase (ERK), and cAMP-response element binding protein (CREB). THPP-1 produced dose-dependent effects in preclinical assays predictive of antipsychotic activity including attenuation of MK-801-induced psychomotor activation and condition avoidance responding in rats. At similar plasma exposures, THPP-1 significantly increased object recognition memory in rat and attenuated a ketamine-induced deficit in the object retrieval detour task in rhesus monkey. These findings suggest that PDE10A inhibitors have the potential to impact multiple symptomatic domains of schizophrenia including positive symptoms and cognitive impairment. This article is part of a Special Issue entitled 'Cognitive Enhancers'.
Asunto(s)
Antipsicóticos/uso terapéutico , Trastornos del Conocimiento/prevención & control , Terapia Molecular Dirigida , Nootrópicos/uso terapéutico , Inhibidores de Fosfodiesterasa/uso terapéutico , Hidrolasas Diéster Fosfóricas/metabolismo , Esquizofrenia/tratamiento farmacológico , Animales , Antipsicóticos/administración & dosificación , Antipsicóticos/sangre , Antipsicóticos/farmacocinética , Conducta Animal/efectos de los fármacos , Trastornos del Conocimiento/etiología , Cuerpo Estriado/efectos de los fármacos , Cuerpo Estriado/enzimología , Cuerpo Estriado/metabolismo , Relación Dosis-Respuesta a Droga , Función Ejecutiva/efectos de los fármacos , Macaca mulatta , Masculino , Memoria Episódica , Proteínas del Tejido Nervioso/antagonistas & inhibidores , Proteínas del Tejido Nervioso/metabolismo , Neuronas/efectos de los fármacos , Neuronas/enzimología , Neuronas/metabolismo , Nootrópicos/administración & dosificación , Nootrópicos/sangre , Nootrópicos/farmacocinética , Inhibidores de Fosfodiesterasa/administración & dosificación , Inhibidores de Fosfodiesterasa/sangre , Inhibidores de Fosfodiesterasa/farmacocinética , Hidrolasas Diéster Fosfóricas/química , Fosforilación/efectos de los fármacos , Procesamiento Proteico-Postraduccional/efectos de los fármacos , Piridinas/administración & dosificación , Piridinas/sangre , Piridinas/farmacocinética , Piridinas/uso terapéutico , Pirimidinas/administración & dosificación , Pirimidinas/sangre , Pirimidinas/farmacocinética , Pirimidinas/uso terapéutico , Distribución Aleatoria , Ratas , Ratas Wistar , Esquizofrenia/sangre , Esquizofrenia/metabolismo , Esquizofrenia/fisiopatologíaRESUMEN
Orexin (hypocretin) neuropeptides promote wakefulness by signaling through two G-protein coupled receptors, Orexin 1 Receptor (OX(1)R) and Orexin 2 Receptor (OX(2)R). MK-6096 is an orally bioavailable potent and selective reversible antagonist of OX(1)R and OX(2)R currently in clinical development for insomnia. In radioligand binding and functional cell based assays MK-6096 demonstrated potent binding and antagonism of both human OX(1)R and OX(2)R (<3 nM in binding, 11 nM in FLIPR), with no significant off-target activities against a panel of >170 receptors and enzymes. MK-6096 occupies 90% of human OX(2)Rs expressed in transgenic rats at a plasma concentration of 142 nM, and dose-dependently reduced locomotor activity and significantly increased sleep in rats (3-30 mg/kg) and dogs (0.25 and 0.5 mg/kg). DORA-22, an analog of MK-6096, exhibits similar sleep promoting properties that are absent OX(1/2)R double knockouts, demonstrating the mechanism of action and specificity of these effects. These findings with a novel, structurally distinct class of OxR antagonists provide further validation of the orexin pathway as an effective target to promote normal sleep. Comparative analysis of the biochemical and pharmacokinetic properties of these compounds relative to other OXR antagonists provides a basis for understanding the attributes critical for in vivo efficacy. This mechanism is distinct from current standard of care such that MK-6096 represents a novel and selective therapeutic for the treatment of insomnia. This article is part of a Special Issue entitled 'Post-Traumatic Stress Disorder'.
Asunto(s)
Piperidinas/farmacología , Pirimidinas/farmacología , Receptores Acoplados a Proteínas G/antagonistas & inhibidores , Receptores de Neuropéptido/antagonistas & inhibidores , Trastornos del Inicio y del Mantenimiento del Sueño/tratamiento farmacológico , Sueño/efectos de los fármacos , Animales , Perros , Ratones , Receptores de Orexina , RatasRESUMEN
Insomnia is a common disorder that can be comorbid with other physical and psychological illnesses. Traditional management of insomnia relies on general central nervous system (CNS) suppression using GABA modulators. Many of these agents fail to meet patient needs with respect to sleep onset, maintenance, and next-day residual effects and have issues related to tolerance, memory disturbances, and balance. Orexin neuropeptides are central regulators of wakefulness, and orexin antagonism has been identified as a novel mechanism for treating insomnia with clinical proof of concept. Herein we describe the discovery of a series of α-methylpiperidine carboxamide dual orexinâ 1 and orexinâ 2 receptor (OX(1) R/OX(2) R) antagonists (DORAs). The design of these molecules was inspired by earlier work from this laboratory in understanding preferred conformational properties for potent orexin receptor binding. Minimization of 1,3-allylic strain interactions was used as a design principle to synthesize 2,5-disubstituted piperidine carboxamides with axially oriented substituents including DORA 28. DORA 28 (MK-6096) has exceptional inâ vivo activity in preclinical sleep models, and has advanced into phaseâ II clinical trials for the treatment of insomnia.
Asunto(s)
Hipnóticos y Sedantes/síntesis química , Piperidinas/síntesis química , Piridinas/síntesis química , Receptores Acoplados a Proteínas G/antagonistas & inhibidores , Receptores de Neuropéptido/antagonistas & inhibidores , Trastornos del Inicio y del Mantenimiento del Sueño/tratamiento farmacológico , Triazoles/síntesis química , Animales , Encéfalo/efectos de los fármacos , Encéfalo/metabolismo , Perros , Descubrimiento de Drogas , Humanos , Hipnóticos y Sedantes/farmacocinética , Hipnóticos y Sedantes/farmacología , Espectroscopía de Resonancia Magnética , Modelos Moleculares , Receptores de Orexina , Piperidinas/farmacocinética , Piperidinas/farmacología , Unión Proteica , Piridinas/farmacocinética , Piridinas/farmacología , Ratas , Receptores Acoplados a Proteínas G/metabolismo , Receptores de Neuropéptido/metabolismo , Sueño , Trastornos del Inicio y del Mantenimiento del Sueño/metabolismo , Estereoisomerismo , Relación Estructura-Actividad , Triazoles/farmacocinética , Triazoles/farmacología , Vigilia/efectos de los fármacosRESUMEN
Despite increased understanding of the biological basis for sleep control in the brain, few novel mechanisms for the treatment of insomnia have been identified in recent years. One notable exception is inhibition of the excitatory neuropeptides orexins A and B by design of orexin receptor antagonists. Herein, we describe how efforts to understand the origin of poor oral pharmacokinetics in a leading HTS-derived diazepane orexin receptor antagonist led to the identification of compound 10 with a 7-methyl substitution on the diazepane core. Though 10 displayed good potency, improved pharmacokinetics, and excellent in vivo efficacy, it formed reactive metabolites in microsomal incubations. A mechanistic hypothesis coupled with an in vitro assay to assess bioactivation led to replacement of the fluoroquinazoline ring of 10 with a chlorobenzoxazole to provide 3 (MK-4305), a potent dual orexin receptor antagonist that is currently being tested in phase III clinical trials for the treatment of primary insomnia.
Asunto(s)
Azepinas/farmacología , Receptores Acoplados a Proteínas G/antagonistas & inhibidores , Receptores de Neuropéptido/antagonistas & inhibidores , Triazoles/farmacología , Animales , Azepinas/síntesis química , Azepinas/farmacocinética , Disponibilidad Biológica , Células CHO , Cricetinae , Cricetulus , Perros , Humanos , Técnicas In Vitro , Masculino , Microsomas Hepáticos/metabolismo , Receptores de Orexina , Ensayo de Unión Radioligante , Ratas , Ratas Sprague-Dawley , Ratas Transgénicas , Receptores Acoplados a Proteínas G/genética , Receptores de Neuropéptido/genética , Sueño/efectos de los fármacos , Trastornos del Inicio y del Mantenimiento del Sueño/tratamiento farmacológico , Estereoisomerismo , Relación Estructura-Actividad , Telemetría , Triazoles/síntesis química , Triazoles/farmacocinética , Vigilia/efectos de los fármacosRESUMEN
Silent Night: Antagonism of the orexin (or hypocretin) system has recently been identified as a novel mechanism for the treatment of insomnia. Herein, we describe discovery of a dual (OX(1)R/OX(2)R) orexin receptor antagonist featuring a 1,4-diazepane central constraint that blocks orexin signaling in vivo. In telemetry-implanted rats, oral administration of this antagonist produced a decrease in wakefulness, while increasing REM and non-REM sleep.
Asunto(s)
Azepinas/química , Receptores Acoplados a Proteínas G/antagonistas & inhibidores , Receptores de Neuropéptido/antagonistas & inhibidores , Trastornos del Sueño-Vigilia/tratamiento farmacológico , Animales , Azepinas/farmacocinética , Azepinas/uso terapéutico , Sistema Nervioso Central/efectos de los fármacos , Receptores de Orexina , Ratas , Receptores Acoplados a Proteínas G/metabolismo , Receptores de Neuropéptido/metabolismo , Relación Estructura-ActividadRESUMEN
Inhibition of kinesin spindle protein (KSP) is a novel mechanism for treatment of cancer with the potential to overcome limitations associated with currently employed cytotoxic agents. Herein, we describe a C2-hydroxymethyl dihydropyrrole KSP inhibitor ( 11) that circumvents hERG channel binding and poor in vivo potency, issues that limited earlier compounds from our program. However, introduction of the C2-hydroxymethyl group caused 11 to be a substrate for cellular efflux by P-glycoprotein (Pgp). Utilizing knowledge garnered from previous KSP inhibitors, we found that beta-fluorination modulated the p K a of the piperidine nitrogen and reduced Pgp efflux, but the resulting compound ( 14) generated a toxic metabolite in vivo. Incorporation of fluorine in a strategic, metabolically benign position by synthesis of an N-methyl-3-fluoro-4-(aminomethyl)piperidine urea led to compound 30 that has an optimal in vitro and metabolic profile. Compound 30 (MK-0731) was recently studied in a phase I clinical trial in patients with taxane-refractory solid tumors.
Asunto(s)
Antineoplásicos/farmacología , Inhibidores Enzimáticos/farmacología , Cinesinas/antagonistas & inhibidores , Neoplasias/enzimología , Piperidinas/farmacología , Pirroles/farmacología , Taxoides/farmacología , Miembro 1 de la Subfamilia B de Casetes de Unión a ATP/metabolismo , Antineoplásicos/uso terapéutico , Inhibidores Enzimáticos/uso terapéutico , Humanos , Neoplasias/tratamiento farmacológico , Taxoides/uso terapéuticoRESUMEN
Installation of a C2-aminopropyl side chain to the 2,4-diaryl-2,5-dihydropyrrole series of kinesin spindle protein (KSP) inhibitors results in potent, water soluble compounds, but the aminopropyl group induces susceptibility to cellular efflux by P-glycoprotein (Pgp). We show that by carefully modulating the basicity of the amino group by beta-fluorination, this series of inhibitors maintains potency against KSP and has greatly improved efficacy in a Pgp-overexpressing cell line. The discovery that cellular efflux by Pgp can be overcome by carefully modulating the basicity of an amine may be of general use to medicinal chemists attempting to transform leading compounds into cancer cell- or CNS-penetrant drugs.
Asunto(s)
Miembro 1 de la Subfamilia B de Casetes de Unión a ATP/fisiología , Flúor/metabolismo , Cinesinas/antagonistas & inhibidores , Propilaminas/farmacología , Pirroles/farmacología , Transporte Biológico , Citoesqueleto , Concentración de Iones de Hidrógeno , Cinesinas/metabolismo , Solubilidad , AguaRESUMEN
Molecular modeling in combination with X-ray crystallographic information was employed to identify a region of the kinesin spindle protein (KSP) binding site not fully utilized by our first generation inhibitors. We discovered that by appending a propylamine substituent at the C5 carbon of a dihydropyrazole core, we could effectively fill this unoccupied region of space and engage in a hydrogen-bonding interaction with the enzyme backbone. This change led to a second generation compound with increased potency, a 400-fold enhancement in aqueous solubility at pH 4, and improved dog pharmacokinetics relative to the first generation compound.
Asunto(s)
Diseño de Fármacos , Cinesinas/antagonistas & inhibidores , Pirazoles/química , Pirazoles/farmacología , Alquilación , Sitio Alostérico , Aminación , Animales , Cristalografía por Rayos X , Perros , Hidroxilación , Cinesinas/química , Cinesinas/metabolismo , Mitosis , Modelos Moleculares , Estructura Molecular , Pirazoles/síntesis química , Pirazoles/farmacocinética , Solubilidad , Relación Estructura-Actividad , AguaRESUMEN
Optimization of high-throughput screening (HTS) hits resulted in the discovery of 3,5-diaryl-4,5-dihydropyrazoles as potent and selective inhibitors of KSP. Dihydropyrazole 15 is a potent, cell-active KSP inhibitor that induces apoptosis and generates aberrant mitotic spindles in human ovarian carcinoma cells at low nanomolar concentrations. X-ray crystallographic evidence is presented which demonstrates that these inhibitors bind in an allosteric pocket of KSP distant from the nucleotide and microtubule binding sites.
Asunto(s)
Proteínas de Ciclo Celular/antagonistas & inhibidores , Cinesinas/antagonistas & inhibidores , Mitosis/efectos de los fármacos , Pirazoles/química , Pirazoles/farmacología , Huso Acromático/efectos de los fármacos , Proteínas de Ciclo Celular/fisiología , Línea Celular Tumoral , Humanos , Cinesinas/fisiología , Mitosis/fisiología , Huso Acromático/química , Huso Acromático/fisiologíaRESUMEN
Two novel series of small-molecule RGD mimetics containing either a substituted pyridone or pyrazinone central constraint were prepared. Modification of the beta-alanine 3-substituent produced compounds that are potent and selective alpha(v)beta(3) antagonists and exhibit a range of physicochemical properties.
Asunto(s)
Integrina alfaVbeta3/antagonistas & inhibidores , Pirazinas/química , Piridonas/química , Alanina/química , Diseño de Fármacos , Humanos , Interacciones Hidrofóbicas e Hidrofílicas , Concentración 50 Inhibidora , Imitación Molecular , Oligopéptidos , Unión Proteica , Pirazinas/farmacocinética , Piridonas/farmacocinética , Radioinmunoensayo , Relación Estructura-ActividadRESUMEN
A series of 3-substituted tetrahydro-[1,8]naphthyridine containing alpha(v)beta(3) antagonists was prepared. A comparison of their in vitro IC(50) values to the electron properties of the 3-substituents revealed a good linear Hammett correlation (rho=-1.96, R(2)=0.959). Electron-withdrawing groups at the 3-position of the tetrahydro-[1,8]naphthyridine decreased potency while electron-donating groups enhanced potency.
Asunto(s)
Antagonistas Adrenérgicos alfa/farmacología , Antagonistas Adrenérgicos beta/farmacología , Integrina alfaVbeta3/antagonistas & inhibidores , Naftiridinas/farmacología , Antagonistas Adrenérgicos alfa/síntesis química , Antagonistas Adrenérgicos beta/síntesis química , Humanos , Estructura Molecular , Naftiridinas/síntesis química , Relación Estructura-ActividadRESUMEN
Subtle modifications were incorporated into the structure of clinical candidate 1. These changes were designed to maintain potency and selectivity while inducing changes in physical properties leading to improved pharmacokinetics in three species. This approach led to the identification of 4 as a potent, selective alphaVbeta3 receptor antagonist that was selected for clinical development based on an improved PK profile and efficacy demonstrated in an in vivo model of bone turnover.