RESUMEN
Antagonism of the gonadotropin releasing hormone (GnRH) receptor has resulted in positive clinical results in reproductive tissue disorders such as endometriosis and prostate cancer. Following the recent discovery of orally active GnRH antagonists based on a 4-piperazinylbenzimidazole template, we sought to investigate the properties of heterocyclic isosteres of the benzimidazole template. We report here the synthesis and biological activity of eight novel scaffolds, including imidazopyridines, benzothiazoles and benzoxazoles. The 2-(4-tert-butylphenyl)-8-(piperazin-1-yl)imidazo[1,2-a]pyridine ring system was shown to have nanomolar binding potency at the human and rat GnRH receptors as well as functional antagonism in vitro. Additional structure-activity relationships within this series are reported along with a pharmacokinetic comparison to the benzimidazole-based lead molecule.
Asunto(s)
Compuestos Heterocíclicos/síntesis química , Compuestos Heterocíclicos/farmacología , Piperazinas/síntesis química , Piperazinas/farmacología , Receptores LHRH/antagonistas & inhibidores , Animales , Disponibilidad Biológica , Células Cultivadas , Semivida , Compuestos Heterocíclicos/farmacocinética , Humanos , Masculino , Piperazinas/farmacocinética , Ratas , Ratas Sprague-DawleyRESUMEN
A series of (hetero)arylpyrimidines agonists of the Wnt-beta-catenin cellular messaging system have been prepared. These compounds show activity in U2OS cells transfected with Wnt-3a, TCF-luciferase, Dkk-1 and tk-Renilla. Selected compounds show minimal GSK-3beta inhibition indicating that the Wnt-beta-catenin agonism activity most likely comes from interaction at Wnt-3a/Dkk-1. Two examples 1 and 25 show in vivo osteogenic activity in a mouse calvaria model. One example 1 is shown to activate non-phosphorylated beta-catenin formation in bone.
Asunto(s)
Imidazoles/química , Pirimidinas/química , Proteínas Wnt/metabolismo , beta Catenina/metabolismo , Animales , Desarrollo Óseo/efectos de los fármacos , Línea Celular Tumoral , Glucógeno Sintasa Quinasa 3/metabolismo , Glucógeno Sintasa Quinasa 3 beta , Humanos , Imidazoles/síntesis química , Imidazoles/farmacología , Péptidos y Proteínas de Señalización Intercelular/genética , Péptidos y Proteínas de Señalización Intercelular/metabolismo , Ratones , Ratones Endogámicos C57BL , Pirimidinas/síntesis química , Pirimidinas/farmacología , Proteínas Recombinantes de Fusión/agonistas , Proteínas Recombinantes de Fusión/genética , Proteínas Recombinantes de Fusión/metabolismo , Transducción de Señal , Cráneo/metabolismo , Proteínas Wnt/agonistas , Proteínas Wnt/genética , Proteína Wnt3 , Proteína Wnt3A , beta Catenina/agonistasRESUMEN
A previous report described the serum LH suppression pharmacology of the 2-phenyl-4-piperazinyl-benzimidazole N-ethyluracil GnRH receptor antagonist 1 following oral administration in rats. A series of small heterocycles were appended to the 2-(4-tert-butylphenyl)-4-piperazinyl-benzimidazole template in place of the N-ethyluracil. Two imidazole analogues, 32 and 41, were shown to possess substantial in vitro potency at the target receptor (hGnRH IC(50) = 7 and 18 nM, respectively) and aqueous solubility (55 and 100 microg/mL at pH 7.4, respectively). Both compounds had high oral bioavailability in rats and 32 was further examined in an orchidectomized rat model for serum LH suppression based on increased volume of distribution over 41. Serum LH levels trended lower in orchidectomized rats following oral administration of 32.
Asunto(s)
Bencimidazoles/farmacología , Piperazinas/farmacología , Receptores LHRH/antagonistas & inhibidores , Administración Oral , Animales , Bencimidazoles/química , Bencimidazoles/farmacocinética , Compuestos Heterocíclicos/síntesis química , Compuestos Heterocíclicos/química , Hormona Luteinizante/sangre , Modelos Animales , Piperazinas/química , Piperazinas/farmacocinética , Ratas , Receptores LHRH/metabolismo , Relación Estructura-Actividad , Factores de TiempoRESUMEN
Using a cell-based assay, we have identified a new series of Notch-sparing gamma-secretase inhibitors from HTS screening leads 2a and 2e. Lead optimization studies led to the discovery of analog 8e with improved gamma-secretase inhibitory potency and Notch-sparing selectivity.
Asunto(s)
Secretasas de la Proteína Precursora del Amiloide/antagonistas & inhibidores , Química Farmacéutica/métodos , Inhibidores Enzimáticos/síntesis química , Inhibidores Enzimáticos/farmacología , Receptores Notch/metabolismo , Enfermedad de Alzheimer/tratamiento farmacológico , Amiloide/química , Secretasas de la Proteína Precursora del Amiloide/química , Carbono/química , Diseño de Fármacos , Evaluación Preclínica de Medicamentos , Humanos , Modelos Químicos , Receptores Notch/antagonistas & inhibidores , Relación Estructura-ActividadRESUMEN
Estrogens play a critical role in the regulation of cellular proliferation, differentiation, and apoptosis. Evidence indicates that this regulation is mediated by a complex interface of direct control of gene expression (so-called "genomic action") and by regulation of cell-signaling/phosphorylation cascades (referred to as the "non-genomic", or "extranuclear" action). However, the mechanisms of the non-genomic action of estrogens are not well defined. We have recently described the identification of a novel scaffold protein termed MNAR (modulator of non-genomic action of estrogen receptor), that couples conventional steroid receptors with extranuclear signal transduction pathways, thus potentially providing additional and tissue- or cell-specific level of steroid hormone regulation of cell functions. We have demonstrated that the MNAR is required for ER alpha (ERa) interaction with p60(src) (Src), which leads to activation of Src/MAPK pathway. Our new data also suggest that activation of cSrc in response to E2 leads to MNAR phosphorylation, interaction with p85, and activation of the PI3 and Akt kinases. These data therefore suggest that MNAR acts as an important scaffold that integrates ERa action in regulation of important signaling pathways. ERa non-genomic action has been suggested to play a key role in estrogen-induced cardio-, neuro-, and osteo-protection. Therefore, evaluation of the molecular crosstalk between MNAR and ERa may lead to development of functionally selective ER modulators that can separate between beneficial, prodifferentiative effects in bone, the cardiovascular system and the CNS and the "detrimental", proliferative effects in reproductive tissues and organs.
Asunto(s)
Receptor alfa de Estrógeno/metabolismo , Estrógenos/metabolismo , Regulación Neoplásica de la Expresión Génica , Fosfatidilinositol 3-Quinasas/metabolismo , Transactivadores/fisiología , Familia-src Quinasas/metabolismo , Dominio Catalítico , Línea Celular Tumoral , Proliferación Celular , Proteínas Co-Represoras , Activación Enzimática , Humanos , Fosforilación , Proteínas Proto-Oncogénicas pp60(c-src)/metabolismo , Transducción de Señal , Relación Estructura-Actividad , Transactivadores/metabolismo , Factores de TranscripciónRESUMEN
Antagonism of the gonadotropin releasing hormone (GnRH) receptor has shown positive clinical results in numerous reproductive tissue disorders such as endometriosis, prostate cancer and others. Traditional therapy has been limited to peptide agonists and antagonists. Recently, small molecule GnRH antagonists have emerged as potentially new treatments. This article describes the discovery of 2-phenyl-4-piperazinylbenzimidazoles as small molecule GnRH antagonists with nanomolar potency in in vitro binding and functional assays, excellent bioavailability (rat %F>70) and demonstrated oral activity in a rat model having shown significant serum leuteinizing hormone (LH) suppression.
Asunto(s)
Bencimidazoles/administración & dosificación , Bencimidazoles/química , Piperazinas/química , Receptores LHRH/antagonistas & inhibidores , Administración Oral , Animales , Bencimidazoles/síntesis química , Reactivos de Enlaces Cruzados/química , Glicolatos/química , Humanos , Hormona Luteinizante/sangre , Masculino , Metilación , Estructura Molecular , Piperazina , Ratas , Ratas Sprague-Dawley , Receptores LHRH/metabolismo , Relación Estructura-ActividadRESUMEN
We have identified novel estrogen receptor alpha (ERalpha) antagonists using both cell-based and computer-based virtual screening strategies. A mammalian two-hybrid screen was used to select compounds that disrupt the interaction between the ERalpha ligand binding domain (LBD) and the coactivator SRC-3. A virtual screen was designed to select compounds that fit onto the LxxLL peptide-binding surface of the receptor, based on the X-ray crystal structure of the ERalpha LBD complexed with a LxxLL peptide. All selected compounds effectively inhibited 17-beta-estradiol induced coactivator recruitment with potency ranging from nano-molar to micromolar. However, in contrast to classical ER antagonists, these novel inhibitors poorly displace estradiol in the ER-ligand competition assay. Nuclear magnetic resonance (NMR) suggested direct binding of these compounds to the receptors pre-complexed with estradiol and further demonstrated that no estradiol displacement occurred. Partial proteolytic enzyme digestion revealed that, when compared with 17-beta-estradiol- and 4 hydroxy-tamoxifen (4-OHT) bound receptors, at least one of these compounds might induce a unique receptor conformation. These small molecules may represent new classes of ER antagonists, and may have the potential to provide an alternative for the current anti-estrogen therapy.
Asunto(s)
Estradiol/análogos & derivados , Antagonistas de Estrógenos/farmacología , Receptores de Estrógenos/antagonistas & inhibidores , Acetiltransferasas , Animales , Antineoplásicos/farmacología , Evaluación Preclínica de Medicamentos/métodos , Estradiol/farmacología , Receptor alfa de Estrógeno , Fulvestrant , Histona Acetiltransferasas , Humanos , Hidroxitestosteronas/farmacología , Ligandos , Coactivador 3 de Receptor Nuclear , Proteínas Oncogénicas , Unión Proteica/efectos de los fármacos , Conformación Proteica/efectos de los fármacos , Receptores de Estrógenos/metabolismo , Transactivadores/metabolismoRESUMEN
A potent, highly insoluble, GnRH antagonist with a 2-phenyl-4-piperazinylbenzimidazole template and a quinoxaline-2,3-dione pharmacophore was modified to maintain GnRH antagonist activity and improve in vitro pharmaceutical properties. Structural changes to the quinoxaline-2,3-dione portion of the molecule resulted in several structures with improved properties and culminated in the discovery of 6-([4-[2-(4-tert-butylphenyl)-1H-benzimidazol-4-yl]piperazin-1-yl] methyl)quinoxaline (WAY-207024). The compound was shown to have excellent pharmacokinetic parameters and lowered rat plasma LH levels after oral administration.
Asunto(s)
Bencimidazoles/síntesis química , Quinoxalinas/síntesis química , Receptores LHRH/antagonistas & inhibidores , Administración Oral , Animales , Bencimidazoles/química , Bencimidazoles/farmacología , Unión Competitiva , Disponibilidad Biológica , Semivida , Humanos , Técnicas In Vitro , Hormona Luteinizante/sangre , Masculino , Microsomas Hepáticos/metabolismo , Orquiectomía , Hipófisis/efectos de los fármacos , Hipófisis/metabolismo , Quinoxalinas/química , Quinoxalinas/farmacología , Ensayo de Unión Radioligante , Ratas , Relación Estructura-ActividadRESUMEN
A high-throughput screening campaign to discover small molecule leads for the treatment of bone disorders concluded with the discovery of a compound with a 2-aminopyrimidine template that targeted the Wnt beta-catenin cellular messaging system. Hit-to-lead in vitro optimization for target activity and molecular properties led to the discovery of (1-(4-(naphthalen-2-yl)pyrimidin-2-yl)piperidin-4-yl)methanamine (5, WAY-262611). Compound 5 has excellent pharmacokinetic properties and showed a dose dependent increase in the trabecular bone formation rate in ovariectomized rats following oral administration.