RESUMO
Addressing resistance to third-generation EGFR TKIs such as osimertinib via the EGFRC797S mutation remains a highly unmet need in EGFR-driven non-small-cell lung cancer (NSCLC). Herein, we present the discovery of the allosteric EGFR inhibitor 57, a novel fourth-generation inhibitor to overcome EGFRC797S-mediated resistance in patients harboring the activating EGFRL858R mutation. 57 exhibits an improved potency compared to previous allosteric EGFR inhibitors. To our knowledge, 57 is the first allosteric EGFR inhibitor that demonstrates robust tumor regression in a mutant EGFRL858R/C797S tumor model. Additionally, 57 is active in an H1975 EGFRL858R/T790M NSCLC xenograft model and shows superior efficacy in combination with osimertinib compared to the single agents. Our data highlight the potential of 57 as a single agent against EGFRL858R/C797S and EGFRL858R/T790M/C797S and as combination therapy for EGFRL858R- and EGFRL858R/T790M-driven NSCLC.
Assuntos
Carcinoma Pulmonar de Células não Pequenas , Neoplasias Pulmonares , Acrilamidas , Compostos de Anilina/farmacologia , Compostos de Anilina/uso terapêutico , Carcinoma Pulmonar de Células não Pequenas/patologia , Resistencia a Medicamentos Antineoplásicos , Receptores ErbB/genética , Humanos , Indóis , Neoplasias Pulmonares/patologia , Mutação , Inibidores de Proteínas Quinases/farmacologia , Inibidores de Proteínas Quinases/uso terapêutico , PirimidinasRESUMO
PURPOSE: Exploration of the chemical, analytical and pharmacokinetic properties of the API, RO7304898, an allosteric EGFR inhibitor, intended to be developed as a mixture of two rapidly interconverting diastereoisomers with composition ratio of approximately 1:1. METHODS: Assessment of diastereoisomer stereochemistry, interconversion rates, binding to EGFR protein, metabolic stability and in vivo PK in Wistar-Han rats was conducted. RESULTS: The two diastereoisomers of the API undergo fast interconversion at physiologically relevant pH and direct EGFR binding studies revealed diastereoisomer B to be the active moiety. Pharmacokinetic studies in rat revealed a low-moderate total plasma clearance of the API along with similar plasma concentration-time profiles for diastereoisomers A and B, and the diastereoisomeric ratio reached stable equilibrium favoring formation of the potent diastereoisomer B. In in vitro incubations, the API was metabolically stable in plasma and hepatocyte suspension incubations in all species tested except that of rat hepatocytes. Additionally, only small species differences in the A:B composition were observed in vitro with the potent diastereoisomer B being the predominant form. CONCLUSIONS: We demonstrated that the API, a mixture of two diastereoisomers; A (impotent) and B (potent), undergoes rapid interconversion which is faster than the apparent distribution and elimination rates of the individual diastereoisomers in vivo in rat, serving to diminish concerns that separate diastereoisomer effects may occur in subsequent pharmacologic and pivotal toxicological studies. Whilst vigilant monitoring of the diastereoisomeric ratio will need to be continued, this data adds confidence on the development pathway for this API to the clinic.
Assuntos
Receptores ErbB , Animais , Cinética , Ratos , Ratos Wistar , EstereoisomerismoRESUMO
Drugs targeting metabotropic glutamate receptor 5 (mGluR5) have therapeutic potential in autism spectrum disorders (ASD), including tuberous sclerosis complex (TSC). The question whether inhibition or potentiation of mGluR5 could be beneficial depends, among other factors, on the specific indication. To facilitate the development of mGluR5 treatment strategies, we tested the therapeutic utility of mGluR5 negative and positive allosteric modulators (an mGluR5 NAM and PAM) for TSC, using a mutant mouse model with neuronal loss of Tsc2 that demonstrates disease-related phenotypes, including behavioral symptoms of ASD and epilepsy. This model uniquely enables the in vivo characterization and rescue of the electrographic seizures associated with TSC. We demonstrate that inhibition of mGluR5 corrects hyperactivity, seizures, and elevated de novo synaptic protein synthesis. Conversely, positive allosteric modulation of mGluR5 results in the exacerbation of hyperactivity and epileptic phenotypes. The data suggest a meaningful therapeutic potential for mGluR5 NAMs in TSC, which warrants clinical exploration and the continued development of mGluR5 therapies.
Assuntos
Receptor de Glutamato Metabotrópico 5/antagonistas & inibidores , Esclerose Tuberosa/tratamento farmacológico , Regulação Alostérica , Animais , Transtorno do Espectro Autista/tratamento farmacológico , Transtorno do Espectro Autista/metabolismo , Encéfalo/efeitos dos fármacos , Encéfalo/metabolismo , Células Cultivadas , Modelos Animais de Doenças , Epilepsia/tratamento farmacológico , Epilepsia/metabolismo , Fármacos Atuantes sobre Aminoácidos Excitatórios/farmacologia , Feminino , Imidazóis/farmacologia , Masculino , Camundongos Transgênicos , Atividade Motora/efeitos dos fármacos , Atividade Motora/fisiologia , Neurônios/efeitos dos fármacos , Neurônios/metabolismo , Fenótipo , Piridinas/farmacologia , Ratos Long-Evans , Receptor de Glutamato Metabotrópico 5/agonistas , Receptor de Glutamato Metabotrópico 5/metabolismo , Esclerose Tuberosa/metabolismo , Proteína 2 do Complexo Esclerose Tuberosa/deficiência , Proteína 2 do Complexo Esclerose Tuberosa/genéticaRESUMO
AIM: The objectives of this first-in-human study were to evaluate the safety and tolerability, pharmacokinetics and pharmacodynamics, and maximum tolerated dose (MTD) of single ascending oral doses of RG7342, a positive allosteric modulator (PAM) of the metabotropic glutamate receptor 5 (mGlu5) for the treatment of schizophrenia, in healthy male subjects. METHODS: This was a single-centre, randomized, double-blind, adaptive study of 37 subjects receiving single ascending oral doses of RG7342 (ranging from 0.06-1.2 mg, n = 27) or placebo (n = 10). A modified continual reassessment method, with control for the probability of overdosing based on the occurrence of dose-limiting events (DLEs), was applied to inform the subsequent dose decisions for RG7342. RESULTS: DLEs consisted of dizziness, nausea and vomiting, and the incidence and severity of these adverse events increased in a concentration-dependent manner. RG7342 doses of 1.2 mg under fasting conditions, which reached a mean maximum plasma concentration (Cmax ) of 10.2 ng ml-1 , were not tolerated (four out of six subjects experienced DLEs). RG7342 showed dose-proportional pharmacokinetics, with rapid absorption and a biphasic decline, and a mean terminal half-life estimated to be >1000 h. CONCLUSIONS: Single oral doses of RG7342 were generally tolerated up to 0.6 mg under fasting and 0.9 mg under fed conditions in healthy subjects. Bayesian adaptive methods describing the probability of DLEs were applied effectively to support dose escalation. MTDs (fasting, fed) were associated with a Cmax of 6.5 ng ml-1 . The development of RG7342 was discontinued owing to the potential challenges associated with a long half-life in context of the observed adverse events.
Assuntos
Regulação Alostérica/efeitos dos fármacos , Interações Alimento-Droga , Receptor de Glutamato Metabotrópico 5/efeitos dos fármacos , Administração Oral , Adolescente , Adulto , Teorema de Bayes , Relação Dose-Resposta a Droga , Método Duplo-Cego , Jejum , Feminino , Meia-Vida , Humanos , Masculino , Dose Máxima Tolerável , Adulto JovemRESUMO
Etiology and pharmacotherapy of stress-related psychiatric conditions and somatoform disorders are areas of high unmet medical need. Stressors holding chronic plus psychosocial components thereby bear the highest health risk. Although the metabotropic glutamate receptor subtype 5 (mGlu5) is well studied in the context of acute stress-induced behaviors and physiology, virtually nothing is known about its potential involvement in chronic psychosocial stress. Using the mGlu5 negative allosteric modulator CTEP (2-chloro-4-[2-[2,5-dimethyl-1-[4-(trifluoromethoxy)phenyl]imidazol-4yl]ethynyl]pyridine), a close analogue of the clinically active drug basimglurant - but optimized for rodent studies, as well as mGlu5-deficient mice in combination with a mouse model of male subordination (termed CSC, chronic subordinate colony housing), we demonstrate that mGlu5 mediates multiple physiological, immunological, and behavioral consequences of chronic psychosocial stressor exposure. For instance, CTEP dose-dependently relieved hypothalamo-pituitary-adrenal axis dysfunctions, colonic inflammation as well as the CSC-induced increase in innate anxiety; genetic ablation of mGlu5 in mice largely reproduced the stress-protective effects of CTEP and additionally ameliorated CSC-induced physiological anxiety. Interestingly, CSC also induced an upregulation of mGlu5 in the hippocampus, a stress-regulating brain area. Taken together, our findings provide evidence that mGlu5 is an important mediator for a wide range of chronic psychosocial stress-induced alterations and a potentially valuable drug target for the treatment of chronic stress-related pathologies in man.
Assuntos
Imidazóis/uso terapêutico , Piridinas/uso terapêutico , Receptor de Glutamato Metabotrópico 5/antagonistas & inibidores , Estresse Psicológico/psicologia , Hormônio Adrenocorticotrópico/sangue , Animais , Ansiedade/etiologia , Ansiedade/psicologia , Doença Crônica , Dominação-Subordinação , Relação Dose-Resposta a Droga , Febre/etiologia , Febre/fisiopatologia , Hidrocortisona/sangue , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Receptor de Glutamato Metabotrópico 5/genética , Meio Social , Regulação para CimaRESUMO
Major depressive disorder (MDD) is a serious public health burden and a leading cause of disability. Its pharmacotherapy is currently limited to modulators of monoamine neurotransmitters and second-generation antipsychotics. Recently, glutamatergic approaches for the treatment of MDD have increasingly received attention, and preclinical research suggests that metabotropic glutamate receptor 5 (mGlu5) inhibitors have antidepressant-like properties. Basimglurant (2-chloro-4-[1-(4-fluoro-phenyl)-2,5-dimethyl-1H-imidazol-4-ylethynyl]-pyridine) is a novel mGlu5 negative allosteric modulator currently in phase 2 clinical development for MDD and fragile X syndrome. Here, the comprehensive preclinical pharmacological profile of basimglurant is presented with a focus on its therapeutic potential for MDD and drug-like properties. Basimglurant is a potent, selective, and safe mGlu5 inhibitor with good oral bioavailability and long half-life supportive of once-daily administration, good brain penetration, and high in vivo potency. It has antidepressant properties that are corroborated by its functional magnetic imaging profile as well as anxiolytic-like and antinociceptive features. In electroencephalography recordings, basimglurant shows wake-promoting effects followed by increased delta power during subsequent non-rapid eye movement sleep. In microdialysis studies, basimglurant had no effect on monoamine transmitter levels in the frontal cortex or nucleus accumbens except for a moderate increase of accumbal dopamine, which is in line with its lack of pharmacological activity on monoamine reuptake transporters. These data taken together, basimglurant has favorable drug-like properties, a differentiated molecular mechanism of action, and antidepressant-like features that suggest the possibility of also addressing important comorbidities of MDD including anxiety and pain as well as daytime sleepiness and apathy or lethargy.
Assuntos
Ansiolíticos/farmacologia , Antidepressivos/farmacologia , Depressão/tratamento farmacológico , Imidazóis/farmacologia , Piridinas/farmacologia , Receptor de Glutamato Metabotrópico 5/antagonistas & inibidores , Regulação Alostérica , Animais , Ansiolíticos/farmacocinética , Ansiolíticos/uso terapêutico , Antidepressivos/farmacocinética , Antidepressivos/uso terapêutico , Monoaminas Biogênicas/metabolismo , Encéfalo/metabolismo , Células Cultivadas , Cricetulus , Depressão/metabolismo , Depressão/psicologia , Agonismo Inverso de Drogas , Eletroencefalografia , Feminino , Imidazóis/farmacocinética , Imidazóis/uso terapêutico , Macaca fascicularis , Masculino , Camundongos , Dor/tratamento farmacológico , Dor/fisiopatologia , Piridinas/farmacocinética , Piridinas/uso terapêutico , Ensaio Radioligante , Ratos Sprague-Dawley , Ratos Wistar , Receptor de Glutamato Metabotrópico 5/metabolismo , Bexiga Urinária Hiperativa/tratamento farmacológico , Bexiga Urinária Hiperativa/fisiopatologiaRESUMO
Human chromosome 16p11.2 microdeletion is the most common gene copy number variation in autism, but the synaptic pathophysiology caused by this mutation is largely unknown. Using a mouse with the same genetic deficiency, we found that metabotropic glutamate receptor 5 (mGluR5)-dependent synaptic plasticity and protein synthesis was altered in the hippocampus and that hippocampus-dependent memory was impaired. Notably, chronic treatment with a negative allosteric modulator of mGluR5 reversed the cognitive deficit.
Assuntos
Transtorno Autístico/fisiopatologia , Transtornos Cromossômicos/fisiopatologia , Hipocampo/fisiopatologia , Imidazóis/farmacologia , Deficiência Intelectual/fisiopatologia , Transtornos da Memória/fisiopatologia , Piridinas/farmacologia , Receptor de Glutamato Metabotrópico 5/fisiologia , Animais , Transtorno Autístico/genética , Transtorno Autístico/metabolismo , Comportamento Animal/efeitos dos fármacos , Comportamento Animal/fisiologia , Deleção Cromossômica , Transtornos Cromossômicos/genética , Transtornos Cromossômicos/metabolismo , Cromossomos Humanos Par 16/genética , Cromossomos Humanos Par 16/metabolismo , Cromossomos de Mamíferos , Modelos Animais de Doenças , Hipocampo/metabolismo , Deficiência Intelectual/genética , Deficiência Intelectual/metabolismo , Masculino , Transtornos da Memória/tratamento farmacológico , Transtornos da Memória/metabolismo , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Plasticidade Neuronal/efeitos dos fármacos , Plasticidade Neuronal/genética , Plasticidade Neuronal/fisiologia , Receptor de Glutamato Metabotrópico 5/genética , Receptor de Glutamato Metabotrópico 5/metabolismo , Transdução de Sinais/efeitos dos fármacos , Transdução de Sinais/genética , Transdução de Sinais/fisiologiaRESUMO
Negative allosteric modulators (NAMs) of metabotropic glutamate receptor 5 (mGlu5) have potential for the treatment of psychiatric diseases including depression, fragile X syndrome (FXS), anxiety, obsessive-compulsive disorders, and levodopa induced dyskinesia in Parkinson's disease. Herein we report the optimization of a weakly active screening hit 1 to the potent and selective compounds chloro-4-[1-(4-fluorophenyl)-2,5-dimethyl-1H-imidazol-4-ylethynyl]pyridine (basimglurant, 2) and 2-chloro-4-((2,5-dimethyl-1-(4-(trifluoromethoxy)phenyl)-1H-imidazol-4-yl)ethynyl)pyridine (CTEP, 3). Compound 2 is active in a broad range of anxiety tests reaching the same efficacy but at a 10- to 100-fold lower dose compared to diazepam and is characterized by favorable DMPK properties in rat and monkey as well as an excellent preclinical safety profile and is currently in phase II clinical studies for the treatment of depression and fragile X syndrome. Analogue 3 is the first reported mGlu5 NAM with a long half-life in rodents and is therefore an ideal tool compound for chronic studies in mice and rats.
Assuntos
Depressão/tratamento farmacológico , Descoberta de Drogas , Síndrome do Cromossomo X Frágil/tratamento farmacológico , Imidazóis/farmacologia , Piridinas/farmacologia , Receptor de Glutamato Metabotrópico 5/antagonistas & inibidores , Regulação Alostérica/efeitos dos fármacos , Animais , Relação Dose-Resposta a Droga , Humanos , Imidazóis/síntese química , Imidazóis/química , Macaca mulatta , Masculino , Camundongos , Camundongos Endogâmicos , Estrutura Molecular , Piridinas/síntese química , Piridinas/química , Ratos , Ratos Sprague-Dawley , Ratos Wistar , Relação Estrutura-AtividadeRESUMO
Fragile X syndrome (FXS) is the most common monogenic form of inherited mental retardation caused by a trinucleotid repeat expansion and transcriptional shutdown of the FMR1 gene. FXS patients present a complex and often severe neuropsychiatric phenotype yet have mild somatic symptoms, normal life expectancies, and no indications of neurodegeneration. The therapeutic potential of mGlu5 inhibitors was proposed in the 'mGluR theory of FXS' based on early insights into the molecular pathophysiology of FXS. Studies in Fragile X mental retardation 1 (Fmr1) knock-out mice, a widely used disease model, demonstrated that mGlu5 inhibitors can correct a broad range of disease-related phenotypes. Recent clinical trials, however, with two different mGlu5 inhibitors (basimglurant and mavoglurant) showed no therapeutic benefit in FXS patients for reasons as yet unclear.
Assuntos
Antagonistas de Aminoácidos Excitatórios/farmacologia , Síndrome do Cromossomo X Frágil/tratamento farmacológico , Receptor de Glutamato Metabotrópico 5/antagonistas & inibidores , Animais , Modelos Animais de Doenças , Antagonistas de Aminoácidos Excitatórios/uso terapêutico , Síndrome do Cromossomo X Frágil/fisiopatologia , Humanos , Imidazóis/farmacologia , Imidazóis/uso terapêutico , Indóis/farmacologia , Indóis/uso terapêutico , Camundongos , Camundongos Knockout , Terapia de Alvo Molecular , Fenótipo , Piridinas/farmacologia , Piridinas/uso terapêuticoRESUMO
Synthetic biology has been heralded as a new bioengineering platform for the production of bulk and specialty chemicals, drugs, and fuels. Here, we report for the first time a series of 74 novel compounds produced using a combinatorial genetics approach in baker's yeast. Based on the concept of "coevolution" with target proteins in an intracellular primary survival assay, the identified, mostly scaffold-sized (200-350 MW) compounds, which displayed excellent biological activity, can be considered as prevalidated hits. Of the molecules found, >75% have not been described previously; 20% of the compounds exhibit novel scaffolds. Their structural and physicochemical properties comply with established rules of drug- and fragment-likeness and exhibit increased structural complexities compared to synthetically produced fragments. In summary, the synthetic biology approach described here represents a completely new, complementary strategy for hit and early lead identification that can be easily integrated into the existing drug discovery process.
Assuntos
Descoberta de Drogas/métodos , Modelos Moleculares , Bibliotecas de Moléculas Pequenas/química , Biologia Sintética/métodos , Leveduras/metabolismo , Bibliotecas de Moléculas Pequenas/metabolismo , Leveduras/genéticaRESUMO
BACKGROUND: Fragile X syndrome (FXS) is the most common genetic cause for intellectual disability. Fmr1 knockout (KO) mice are an established model of FXS. Chronic pharmacological inhibition of metabotropic glutamate receptor 5 (mGlu5) in these mice corrects multiple molecular, physiological, and behavioral phenotypes related to patients' symptoms. To better understand the pathophysiology of FXS and the effect of treatment, brain activity was analyzed using functional magnetic resonance imaging in relation to learning and memory performance. METHODS: Wild-type (WT) and Fmr1 KO animals receiving chronic treatment with the mGlu5 inhibitor CTEP or vehicle were evaluated consecutively for 1) learning and memory performance in the inhibitory avoidance and extinction test, and 2) for the levels of brain activity using continuous arterial spin labeling based functional magnetic resonance imaging. Neural activity patterns were correlated with cognitive performance using a multivariate regression analysis. Furthermore, mGlu5 receptor expression in brains of untreated mice was analyzed by autoradiography and saturation analysis using [(3)H]-ABP688. RESULTS: Chronic CTEP treatment corrected the learning deficit observed in Fmr1 KO mice in the inhibitory avoidance and extinction test and prevented memory extinction in WT and Fmr1 KO animals. Chronic CTEP treatment normalized perfusion in the amygdala and the lateral hypothalamus in Fmr1 KO mice and furthermore decreased perfusion in the hippocampus and increased perfusion in primary sensorimotor cortical areas. No significant differences in mGlu5 receptor expression levels between Fmr1 WT and KO mice were detected. CONCLUSIONS: Chronic mGlu5 inhibition corrected the learning deficits and partially normalized the altered brain activity pattern in Fmr1 KO mice.
Assuntos
Encéfalo/efeitos dos fármacos , Cognição/efeitos dos fármacos , Antagonistas de Aminoácidos Excitatórios/uso terapêutico , Síndrome do Cromossomo X Frágil/tratamento farmacológico , Receptor de Glutamato Metabotrópico 5/antagonistas & inibidores , Animais , Aprendizagem da Esquiva/efeitos dos fármacos , Encéfalo/irrigação sanguínea , Modelos Animais de Doenças , Eletrochoque/efeitos adversos , Antagonistas de Aminoácidos Excitatórios/farmacocinética , Extinção Psicológica/efeitos dos fármacos , Proteína do X Frágil da Deficiência Intelectual/genética , Proteína do X Frágil da Deficiência Intelectual/metabolismo , Síndrome do Cromossomo X Frágil/genética , Síndrome do Cromossomo X Frágil/patologia , Imidazóis/uso terapêutico , Camundongos , Camundongos Knockout , Oximas/farmacocinética , Oxigênio/sangue , Piridinas/farmacocinética , Piridinas/uso terapêutico , Receptor de Glutamato Metabotrópico 5/metabolismo , Trítio/farmacocinéticaRESUMO
BACKGROUND: Previous studies have demonstrated a profound lack of habituation in 129P3 mice compared to the habituating, but initially more anxious, BALB/c mice. The present study investigated whether this non-adaptive phenotype of 129P3 mice is primarily based on anxiety-related characteristics. METHODS: To test this hypothesis and extend our knowledge on the behavioural profile of 129P3 mice, the effects of the anxiolyticdiazepam (1, 3 and 5 mg/kg) and the putative anxiolytic metabotropic glutamate receptor 5 (mGlu5R) antagonist 2-methyl-6-(phenylethynyl)pyridine (MPEP, 3, 10 and 30 mg/kg) treatment on within-trial (intrasession) habituation, object recognition (diazepam: 1 mg/kg; MPEP 10 mg/kg) and on the central-nervous expression of the immediate early gene c-Fos (diazepam: 1 mg/kg; MPEP 10 mg/kg) were investigated. RESULTS: Behavioural findings validated the initially high, but habituating phenotype of BALB/c mice, while 129P3 mice were characterized by impaired intrasession habituation. Diazepam had an anxiolytic effect in BALB/c mice, while in higher doses caused behavioural inactivity in 129P3 mice. MPEP revealed almost no anxiolytic effects on behaviour in both strains, but reduced stress-induced corticosterone responses only in 129P3 mice. These results were complemented by reduced expression of c-Fos after MPEP treatment in brain areas related to emotional processes, and increased c-Fos expression in higher integrating brain areas such as the prelimbic cortex compared to vehicle-treated 129P3 mice. CONCLUSIONS: These results suggest that the strain differences observed in (non)adaptive anxiety behaviour are at least in part mediated by differences in gamma-aminobutyric acid- A and mGluR5 mediated transmission.
Assuntos
Aprendizagem da Esquiva/efeitos dos fármacos , Aprendizagem da Esquiva/fisiologia , Diazepam/farmacologia , Habituação Psicofisiológica/efeitos dos fármacos , Habituação Psicofisiológica/genética , Piridinas/farmacologia , Animais , Masculino , Camundongos , Camundongos da Linhagem 129 , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos , Distribuição AleatóriaRESUMO
Fragile X syndrome (FXS) is the most common form of inherited intellectual disability. Previous studies have implicated mGlu5 in the pathogenesis of the disease, but a crucial unanswered question is whether pharmacological mGlu5 inhibition is able to reverse an already established FXS phenotype in mammals. Here we have used the novel, potent, and selective mGlu5 inhibitor CTEP to address this issue in the Fmr1 knockout mouse. Acute CTEP treatment corrects elevated hippocampal long-term depression, protein synthesis, and audiogenic seizures. Chronic treatment that inhibits mGlu5 within a receptor occupancy range of 81% ± 4% rescues cognitive deficits, auditory hypersensitivity, aberrant dendritic spine density, overactive ERK and mTOR signaling, and partially corrects macroorchidism. This study shows that a comprehensive phenotype correction in FXS is possible with pharmacological intervention starting in young adulthood, after development of the phenotype. It is of great interest how these findings may translate into ongoing clinical research testing mGlu5 inhibitors in FXS patients.
Assuntos
Antagonistas de Aminoácidos Excitatórios/uso terapêutico , Síndrome do Cromossomo X Frágil/tratamento farmacológico , Imidazóis/uso terapêutico , Piridinas/uso terapêutico , Receptores de Glutamato Metabotrópico/efeitos dos fármacos , Fatores Etários , Animais , Modelos Animais de Doenças , Esquema de Medicação , Proteína do X Frágil da Deficiência Intelectual/genética , Síndrome do Cromossomo X Frágil/metabolismo , Hipocampo/efeitos dos fármacos , Hipocampo/metabolismo , Masculino , Camundongos , Camundongos Knockout , Fenótipo , Receptor de Glutamato Metabotrópico 5 , Receptores de Glutamato Metabotrópico/metabolismoRESUMO
The metabotropic glutamate receptor 5 (mGlu5) is a glutamate-activated class C G protein-coupled receptor widely expressed in the central nervous system and clinically investigated as a drug target for a range of indications, including depression, Parkinson's disease, and fragile X syndrome. Here, we present the novel potent, selective, and orally bioavailable mGlu5 negative allosteric modulator with inverse agonist properties 2-chloro-4-((2,5-dimethyl-1-(4-(trifluoromethoxy)phenyl)-1H-imidazol-4-yl)ethynyl)pyridine (CTEP). CTEP binds mGlu5 with low nanomolar affinity and shows >1000-fold selectivity when tested against 103 targets, including all known mGlu receptors. CTEP penetrates the brain with a brain/plasma ratio of 2.6 and displaces the tracer [(3)H]3-(6-methyl-pyridin-2-ylethynyl)-cyclohex-2-enone-O-methyl-oxime (ABP688) in vivo in mice from brain regions expressing mGlu5 with an average ED(50) equivalent to a drug concentration of 77.5 ng/g in brain tissue. This novel mGlu5 inhibitor is active in the stress-induced hyperthermia procedure in mice and the Vogel conflict drinking test in rats with minimal effective doses of 0.1 and 0.3 mg/kg, respectively, reflecting a 30- to 100-fold higher in vivo potency compared with 2-methyl-6-(phenylethynyl)pyridine (MPEP) and fenobam. CTEP is the first reported mGlu5 inhibitor with both long half-life of approximately 18 h and high oral bioavailability allowing chronic treatment with continuous receptor blockade with one dose every 48 h in adult and newborn animals. By enabling long-term treatment through a wide age range, CTEP allows the exploration of the full therapeutic potential of mGlu5 inhibitors for indications requiring chronic receptor inhibition.
Assuntos
Comportamento Animal/efeitos dos fármacos , Encéfalo/metabolismo , Febre/tratamento farmacológico , Imidazóis/farmacologia , Imidazóis/farmacocinética , Piridinas/farmacologia , Piridinas/farmacocinética , Receptores de Glutamato Metabotrópico/antagonistas & inibidores , Administração Oral , Regulação Alostérica/efeitos dos fármacos , Animais , Ansiolíticos/farmacologia , Disponibilidade Biológica , Barreira Hematoencefálica/efeitos dos fármacos , Encéfalo/efeitos dos fármacos , Cálcio/metabolismo , AMP Cíclico/metabolismo , Avaliação Pré-Clínica de Medicamentos , Células HEK293 , Humanos , Imidazóis/administração & dosagem , Imidazóis/metabolismo , Fosfatos de Inositol/metabolismo , Masculino , Camundongos , Terapia de Alvo Molecular , Plasmídeos , Piridinas/administração & dosagem , Piridinas/metabolismo , Ensaio Radioligante , Ratos , Ratos Sprague-Dawley , Receptor de Glutamato Metabotrópico 5 , Receptores de Glutamato Metabotrópico/agonistasRESUMO
Detailed information on the metabolic fate of lead compounds can be a powerful tool for an informed approach to the stabilization of metabolically labile compounds in the lead optimization phase. The combination of high performance liquid chromatography (HPLC) with nuclear magnetic resonance (NMR) spectroscopy and mass spectrometry (MS) has been used to give comprehensive structural data on metabolites of novel drugs in development. Recently, increased automation and the embedding of on-line solid-phase extraction (SPE) into a integrated LC-SPE-NMR-MS system have improved enormously the detection limits of this approach. The new technology platform allows the analysis of complex mixtures from microsome incubations, combining low material requirements with relatively high throughput. Such characteristics make it possible to thoroughly characterize metabolites of selected compounds at earlier phases along the path to lead identification and clinical candidate selection, thus providing outstanding guidance in the process of eliminating undesired metabolism and detecting active or potentially toxic metabolites. Such an approach was applied at the lead identification stage of a backup program on metabotropic glutamate receptor 5 (mGlu5) allosteric inhibition. The major metabolites of a lead 5-aminothiazole-4-carboxylic acid amide 1 were synthesized and screened, revealing significant in vitro activity and possible involvement in the overall pharmacodynamic behavior of 1. The information collected on the metabolism of the highly active compound 1 was pivotal to the synthesis of related compounds with improved microsomal stability.
Assuntos
Aminopiridinas/metabolismo , Microssomos Hepáticos/metabolismo , Preparações Farmacêuticas/metabolismo , Receptores de Glutamato Metabotrópico/antagonistas & inibidores , Tiazóis/metabolismo , Regulação Alostérica , Aminopiridinas/síntese química , Cromatografia Líquida de Alta Pressão/métodos , Humanos , Concentração Inibidora 50 , Espectroscopia de Ressonância Magnética/métodos , Espectrometria de Massas/métodos , Microssomos Hepáticos/química , Oxirredução , Preparações Farmacêuticas/síntese química , Receptor de Glutamato Metabotrópico 5 , Extração em Fase Sólida/métodos , Estereoisomerismo , Tiazóis/síntese químicaRESUMO
The enantioselective total synthesis of callipeltoside A is described. Two syntheses of the macrolactone subunit are included: the first relies upon an Ireland-Claisen rearrangement to generate the trisubstituted olefin geometry and the second utilizes an enantioselective vinylogous aldol reaction for this purpose. Enantioselective syntheses of the sugar and chlorocyclopropane side chain fragments are also disclosed. The relative and absolute stereochemistry of this natural product was determined by fragment coupling with the two enantiomers of the side chain fragment.
RESUMO
The mGlu5 receptor antagonist 2-methyl-6-(phenylethylnyl)-pyridine (MPEP) is highly anxiolytic in rodent models of anxiety. Recent studies showed that MPEP remains effective in some models of anxiety after repeated treatment, but tolerance may develop in other models. To further evaluate anxiolytic properties of repeated MPEP, a single administration of 3, 10, or 30 mg/kg p.o. and repeated administration of 30 mg/kg p.o. was tested in the stress-induced hyperthermia model in mice. MPEP dose-dependently inhibited stress-induced hyperthermia when given acutely. MPEP remained equally active in reducing stress-induced hyperthermia after five daily treatments with 30 mg/kg, further validating MPEP as a potential anxiolytic for chronic use.
Assuntos
Ansiolíticos/administração & dosagem , Antagonistas de Aminoácidos Excitatórios/administração & dosagem , Febre/tratamento farmacológico , Piridinas/administração & dosagem , Receptores de Glutamato Metabotrópico/antagonistas & inibidores , Animais , Ansiedade/tratamento farmacológico , Ansiedade/fisiopatologia , Febre/fisiopatologia , Masculino , Camundongos , Camundongos Endogâmicos , Receptor de Glutamato Metabotrópico 5 , Estresse Psicológico/complicaçõesRESUMO
This review describes simple and useful concepts for predicting and tuning the pK(a) values of basic amine centers, a crucial step in the optimization of physical and ADME properties of many lead structures in drug-discovery research. The article starts with a case study of tricyclic thrombin inhibitors featuring a tertiary amine center with pK(a) values that can be tuned over a wide range, from the usual value of around 10 to below 2 by (remote) neighboring functionalities commonly encountered in medicinal chemistry. Next, the changes in pK(a) of acyclic and cyclic amines upon substitution by fluorine, oxygen, nitrogen, and sulfur functionalities, as well as carbonyl and carboxyl derivatives are systematically analyzed, leading to the derivation of simple rules for pK(a) prediction. Electronic and stereoelectronic effects in cyclic amines are discussed, and the emerging computational methods for pK(a) predictions are briefly surveyed. The rules for tuning amine basicities should not only be of interest in drug-discovery research, but also to the development of new crop-protection agents, new amine ligands for organometallic complexes, and in particular, to the growing field of amine-based organocatalysis.
Assuntos
Aminas/química , Química Farmacêutica , Antitrombinas/química , Desenho de Fármacos , Armazenamento e Recuperação da InformaçãoRESUMO
Optimization of affinity and microsomal stability led to identification of the potent, metabolically stable fenobam analog 4l. Robust in vivo efficacy of 4l was demonstrated in four different models of anxiety. Additionally, a ligand based pharmacophore alignment of fenobam and MPEP is proposed.