RESUMO
This Letter details our efforts to develop novel tricyclic muscarinic acetylcholine receptor subtype 4 (M4) positive allosteric modulator (PAM) scaffolds with improved pharmacological properties. This endeavor involved a "tie-back" strategy to replace the 3-amino-5-chloro-4,6-dimethylthieno[2,3-b]pyridine-2-carboxamide core, which led to the discovery of two novel tricyclic cores: an 8-chloro-9-methylpyrido[3',2':4,5]thieno[3,2-d]pyrimidin-4-amine core and 8-chloro-7,9-dimethylpyrido[3',2':4,5]furo[3,2-d]pyrimidin-4-amine core. Both tricyclic cores displayed low nanomolar potency against human M4 and greatly reduced cytochrome P450 inhibition when compared with parent compound ML253.
RESUMO
In this manuscript, we report a series of chiral 6-azaspiro[2.5]octanes and related spirocycles as highly potent and selective antagonists of the muscarinic acetylcholine receptor subtype 4 (mAChR4). Chiral separation and subsequent X-ray crystallographic analysis of early generation analogs revealed the R enantiomer to possess excellent human and rat M4 potency, and further structure-activity relationship (SAR) studies on this chiral scaffold led to the discovery of VU6015241 (compound 19). Compound 19 is characterized by high M4 potency and selectivity across multiple species, excellent aqueous solubility, and moderate brain exposure in rodents after intraperitoneal administration.
Assuntos
Antagonistas Muscarínicos/farmacologia , Receptor Muscarínico M4/antagonistas & inibidores , Relação Dose-Resposta a Droga , Humanos , Estrutura Molecular , Antagonistas Muscarínicos/síntese química , Antagonistas Muscarínicos/química , Receptor Muscarínico M4/metabolismo , Relação Estrutura-AtividadeRESUMO
BACKGROUND: Current melphalan-based intravitreal regimens for retinoblastoma (RB) vitreous seeds cause retinal toxicity. We assessed the efficacy and toxicity of topotecan monotherapy compared with melphalan in our rabbit model and patient cohort. METHODS: Rabbit experiments: empiric pharmacokinetics were determined following topotecan injection. For topotecan (15 µg or 30 µg), melphalan (12.5 µg) or saline, toxicity was evaluated by serial electroretinography (ERG) and histopathology, and efficacy against vitreous seed xenografts was measured by tumour cell reduction and apoptosis induction. PATIENTS: retrospective cohort study of 235 patients receiving 990 intravitreal injections of topotecan or melphalan. RESULTS: Intravitreal topotecan 30 µg (equals 60 µg in humans) achieved the IC90 across the rabbit vitreous. Three weekly topotecan injections (either 15 µg or 30 µg) caused no retinal toxicity in rabbits, whereas melphalan 12.5 µg (equals 25 µg in humans) reduced ERG amplitudes 42%-79%. Intravitreal topotecan 15 µg was equally effective to melphalan to treat WERI-Rb1 cell xenografts in rabbits (96% reduction for topotecan vs saline (p=0.004), 88% reduction for melphalan vs saline (p=0.004), topotecan vs melphalan, p=0.15). In our clinical study, patients received 881 monotherapy injections (48 topotecan, 833 melphalan). Patients receiving 20 µg or 30 µg topotecan demonstrated no significant ERG reductions; melphalan caused ERG reductions of 7.6 µV for every injection of 25 µg (p=0.03) or 30 µg (p<0.001). Most patients treated with intravitreal topotecan also received intravitreal melphalan at some point during their treatment course. Among those eyes treated exclusively with topotecan monotherapy, all eyes were salvaged. CONCLUSIONS: Taken together, these experiments suggest that intravitreal topotecan monotherapy for the treatment of RB vitreous seeds is non-toxic and effective.
Assuntos
Neoplasias da Retina , Retinoblastoma , Animais , Antineoplásicos Alquilantes/toxicidade , Humanos , Injeções Intravítreas , Melfalan/toxicidade , Inoculação de Neoplasia , Coelhos , Neoplasias da Retina/tratamento farmacológico , Neoplasias da Retina/patologia , Retinoblastoma/tratamento farmacológico , Retinoblastoma/patologia , Estudos Retrospectivos , Topotecan/toxicidade , Corpo Vítreo/patologiaRESUMO
Purpose: Current melphalan-based regimens for intravitreal chemotherapy for retinoblastoma vitreous seeds are effective but toxic to the retina. Thus, alternative agents are needed. Based on the known biology of histone deacetylases (HDACs) in the retinoblastoma pathway, we systematically studied whether the HDAC inhibitor belinostat is a viable, molecularly targeted alternative agent for intravitreal delivery that might provide comparable efficacy, without toxicity. Methods: In vivo pharmacokinetic experiments in rabbits and in vitro cytotoxicity experiments were performed to determine the 90% inhibitory concentration (IC90). Functional toxicity by electroretinography and structural toxicity by optical coherence tomography (OCT), OCT angiography, and histopathology were evaluated in rabbits following three injections of belinostat 350 µg (2× IC90) or 700 µg (4× IC90), compared with melphalan 12.5 µg (rabbit equivalent of the human dose). The relative efficacy of intravitreal belinostat versus melphalan to treat WERI-Rb1 human cell xenografts in rabbit eyes was directly quantified. RNA sequencing was used to assess belinostat-induced changes in RB cell gene expression. Results: The maximum nontoxic dose of belinostat was 350 µg, which caused no reductions in electroretinography parameters, retinal microvascular loss on OCT angiography, or retinal degeneration. Melphalan caused severe retinal structural and functional toxicity. Belinostat 350 µg (equivalent to 700 µg in the larger human eye) was equally effective at eradicating vitreous seeds in the rabbit xenograft model compared with melphalan (95.5% reduction for belinostat, P < 0.001; 89.4% reduction for melphalan, P < 0.001; belinostat vs. melphalan, P = 0.10). Even 700 µg belinostat (equivalent to 1400 µg in humans) caused only minimal toxicity. Widespread changes in gene expression resulted. Conclusions: Molecularly targeted inhibition of HDACs with intravitreal belinostat was equally effective as standard-of-care melphalan but without retinal toxicity. Belinostat may therefore be an attractive agent to pursue clinically for intravitreal treatment of retinoblastoma.
Assuntos
Modelos Animais de Doenças , Inibidores de Histona Desacetilases/uso terapêutico , Ácidos Hidroxâmicos/uso terapêutico , Inoculação de Neoplasia , Retina/efeitos dos fármacos , Neoplasias da Retina/tratamento farmacológico , Retinoblastoma/tratamento farmacológico , Sulfonamidas/uso terapêutico , Animais , Anexina A5 , Antineoplásicos Alquilantes/uso terapêutico , Eletrorretinografia , Angiofluoresceinografia , Inibidores de Histona Desacetilases/farmacocinética , Inibidores de Histona Desacetilases/toxicidade , Ácidos Hidroxâmicos/farmacocinética , Ácidos Hidroxâmicos/toxicidade , Injeções Intravítreas , Dose Máxima Tolerável , Melfalan/uso terapêutico , Coelhos , Retina/fisiologia , Neoplasias da Retina/diagnóstico , Neoplasias da Retina/fisiopatologia , Retinoblastoma/diagnóstico , Retinoblastoma/fisiopatologia , Estudos Retrospectivos , Sulfonamidas/farmacocinética , Sulfonamidas/toxicidade , Tomografia de Coerência Óptica , Corpo Vítreo/metabolismo , Ensaios Antitumorais Modelo de XenoenxertoRESUMO
This Letter details our efforts to develop novel tricyclic M4 PAM scaffolds with improved pharmacological properties. This endeavor involved a "tie-back" strategy to replace the 3-amino-4,6-dimethylthieno[2,3-b]pyridine-2-carboxamide core which lead to the discovery of two novel tricyclic cores: a 7,9-dimethylpyrido[3',2':4,5]thieno[3,2-d]pyrimidine core and 2,4-dimethylthieno[2,3-b:5,4-c']dipyridine core. Both tricyclic cores displayed low nanomolar potency against the human M4 receptor.
Assuntos
Descoberta de Drogas , Pirimidinas/farmacologia , Receptor Muscarínico M4/antagonistas & inibidores , Relação Dose-Resposta a Droga , Humanos , Estrutura Molecular , Pirimidinas/síntese química , Pirimidinas/química , Receptor Muscarínico M4/metabolismo , Relação Estrutura-AtividadeRESUMO
Nonselective antagonists of muscarinic acetylcholine receptors (mAChRs) that broadly inhibit all five mAChR subtypes provide an efficacious treatment for some movement disorders, including Parkinson's disease and dystonia. Despite their efficacy in these and other central nervous system disorders, antimuscarinic therapy has limited utility due to severe adverse effects that often limit their tolerability by patients. Recent advances in understanding the roles that each mAChR subtype plays in disease pathology suggest that highly selective ligands for individual subtypes may underlie the antiparkinsonian and antidystonic efficacy observed with the use of nonselective antimuscarinic therapeutics. Our recent work has indicated that the M4 muscarinic acetylcholine receptor has several important roles in opposing aberrant neurotransmitter release, intracellular signaling pathways, and brain circuits associated with movement disorders. This raises the possibility that selective antagonists of M4 may recapitulate the efficacy of nonselective antimuscarinic therapeutics and may decrease or eliminate the adverse effects associated with these drugs. However, this has not been directly tested due to lack of selective antagonists of M4. Here, we utilize genetic mAChR knockout animals in combination with nonselective mAChR antagonists to confirm that the M4 receptor activation is required for the locomotor-stimulating and antiparkinsonian efficacy in rodent models. We also report the synthesis, discovery, and characterization of the first-in-class selective M4 antagonists VU6013720, VU6021302, and VU6021625 and confirm that these optimized compounds have antiparkinsonian and antidystonic efficacy in pharmacological and genetic models of movement disorders.
RESUMO
Herein, we report the SAR leading to the discovery of VU6028418, a potent M4 mAChR antagonist with high subtype-selectivity and attractive DMPK properties in vitro and in vivo across multiple species. VU6028418 was subsequently evaluated as a preclinical candidate for the treatment of dystonia and other movement disorders. During the characterization of VU6028418, a novel use of deuterium incorporation as a means to modulate CYP inhibition was also discovered.
RESUMO
Degeneration of basal forebrain cholinergic circuitry represents an early event in the development of Alzheimer's disease (AD). These alterations in central cholinergic function are associated with disruptions in arousal, sleep/wake architecture, and cognition. Changes in sleep/wake architecture are also present in normal aging and may represent a significant risk factor for AD. M1 muscarinic acetylcholine receptor (mAChR) positive allosteric modulators (PAMs) have been reported to enhance cognition across preclinical species and may also provide beneficial effects for age- and/or neurodegenerative disease-related changes in arousal and sleep. In the present study, electroencephalography was conducted in young animals (mice, rats and nonhuman primates [NHPs]) and in aged mice to examine the effects of the selective M1 PAM VU0453595 in comparison with the acetylcholinesterase inhibitor donepezil, M1/M4 agonist xanomeline (in NHPs), and M1 PAM BQCA (in rats) on sleep/wake architecture and arousal. In young wildtype mice, rats, and NHPs, but not in M1 mAChR KO mice, VU0453595 produced dose-related increases in high frequency gamma power, a correlate of arousal and cognition enhancement, without altering duration of time across all sleep/wake stages. Effects of VU0453595 in NHPs were observed within a dose range that did not induce cholinergic-mediated adverse effects. In contrast, donepezil and xanomeline increased time awake in rodents and engendered dose-limiting adverse effects in NHPs. Finally, VU0453595 attenuated age-related decreases in REM sleep duration in aged wildtype mice. Development of M1 PAMs represents a viable strategy for attenuating age-related and dementia-related pathological disturbances of sleep and arousal.
Assuntos
Doenças Neurodegenerativas , Roedores , Regulação Alostérica , Animais , Nível de Alerta , Camundongos , Primatas , Piridinas , Pirróis , Ratos , Receptor Muscarínico M1 , SonoRESUMO
This Letter details our efforts to discover structurally unique M4 PAMs containing 5,6-heteroaryl ring systems. In an attempt to improve the DMPK profiles of the 2,3-dimethyl-2H-indazole-5-carboxamide and 1-methyl-1H-benzo[d][1,2,3]triazole-6-carboxamide cores, we investigated a plethora of core replacements. This exercise identified a novel 2,3-dimethylimidazo[1,2-a]pyrazine-6-carboxamide core that provided improved M4 PAM activity and CNS penetration.
Assuntos
Imidazóis/química , Pirazinas/química , Receptor Muscarínico M4/química , Regulação Alostérica , Desenho de Fármacos , Avaliação Pré-Clínica de Medicamentos , Humanos , Imidazóis/metabolismo , Cinética , Ligação Proteica , Pirazinas/metabolismo , Receptor Muscarínico M4/metabolismo , Relação Estrutura-AtividadeRESUMO
This Letter details our efforts to develop new M4 PAM scaffolds with improved pharmacological properties. This endeavor involved replacing the 3,4-dimethylpyridazine core with two novel cores: a 2,3-dimethyl-2H-indazole-5-carboxamide core or a 1-methyl-1H-benzo[d][1,2,3]triazole-6-carboxamide core. Due to shallow SAR, these cores were further evolved into two unique tricyclic cores: an 8,9-dimethyl-8H-pyrazolo[3,4-h]quinazoline core and an 1-methyl-1H-[1,2,3]triazolo[4,5-h]quinazoline core. Both tricyclic cores displayed low nanomolar potency against both human and rat M4.
Assuntos
Piridazinas/química , Quinazolinas/química , Receptor Muscarínico M4/química , Triazóis/química , Regulação Alostérica , Animais , Desenho de Fármacos , Meia-Vida , Humanos , Concentração Inibidora 50 , Piridazinas/metabolismo , Piridazinas/farmacocinética , Quinazolinas/metabolismo , Quinazolinas/farmacocinética , Ratos , Receptor Muscarínico M4/metabolismo , Relação Estrutura-Atividade , Triazóis/metabolismo , Triazóis/farmacocinéticaRESUMO
This Letter details our efforts to replace the 2,4-dimethylquinoline carboxamide core of our previous M4 PAM series, which suffered from high predicted hepatic clearance and protein binding. A scaffold hopping exercise identified a novel 3,4-dimethylcinnoline carboxamide core that provided good M4 PAM activity and improved clearance and protein binding profiles.
Assuntos
Receptor Muscarínico M4/química , Regulação Alostérica , Amidas/química , Azetidinas/química , Benzeno/química , Estrutura Molecular , Ligação Proteica , Pirazinas/química , Piridinas/química , Pirimidinas/química , Relação Estrutura-AtividadeRESUMO
Opioid use disorder (OUD) is a debilitating neuropsychiatric condition characterized by compulsive opioid use, dependence, and repeated relapse after periods of abstinence. Given the high risk of developing OUD following prescription opioid use, the continued need for opioid-induced analgesia, and the limitations of current OUD treatments, it is necessary to develop novel, non-opioid-based treatments for OUD and decrease abuse potential of prescription opioids. Recent evidence suggests that negative allosteric modulation (NAM) of the M5 muscarinic acetylcholine receptor (M5 mAChR) may provide an alternative therapeutic approach for the treatment of OUD. Previous studies demonstrated localization of M5 mAChR expression within the mesocorticolimbic reward circuitry and that the selective M5 NAM ML375 attenuates both cocaine and alcohol self-administration in rats. In the present study, the effects of ML375 were evaluated in rats self-administering the µ-opioid agonists oxycodone or remifentanil on a progressive ratio (PR) schedule or on cue reactivity (a rodent model of relapse) in the absence of oxycodone following 72 h of abstinence. ML375 reduced the PR break point for oxycodone and remifentanil self-administration and attenuated cue-elicited responding. Importantly, ML375 did not affect sucrose pellet-maintained responding on a PR schedule or opioid-induced antinociception using the hot-plate and tail-flick assays. We also confirm expression of M5 mAChR mRNA in the ventral tegmental area and show that this is primarily on dopamine (tyrosine hydroxylase mRNA-positive) neurons. Taken together, these findings suggest that selective functional antagonism of the M5 mAChR may represent a novel, non-opioid-based treatment for OUD.
Assuntos
Regulação Alostérica/efeitos dos fármacos , Entorpecentes/administração & dosagem , Nociceptividade/efeitos dos fármacos , Oxicodona/administração & dosagem , Receptor Muscarínico M5/metabolismo , Animais , Comportamento Animal/efeitos dos fármacos , Condicionamento Operante/efeitos dos fármacos , Condicionamento Psicológico/efeitos dos fármacos , Sinais (Psicologia) , Masculino , Ratos , Ratos Sprague-Dawley , Remifentanil/administração & dosagem , Recompensa , AutoadministraçãoRESUMO
This letter describes progress towards an M4 PAM preclinical candidate inspired by an unexpected aldehyde oxidase (AO) metabolite of a novel, CNS penetrant thieno[2,3-c]pyridine core to an equipotent, non-CNS penetrant thieno[2,3-c]pyrdin-7(6H)-one core. Medicinal chemistry design efforts yielded two novel tricyclic cores that enhanced M4 PAM potency, regained CNS penetration, displayed favorable DMPK properties and afforded robust in vivo efficacy in reversing amphetamine-induced hyperlocomotion in rats.
Assuntos
Aldeído Oxidase/metabolismo , Miotonia Congênita/metabolismo , Receptor Muscarínico M4/metabolismo , Animais , Descoberta de Drogas , Humanos , Ratos , Relação Estrutura-AtividadeRESUMO
This letter describes progress towards an M4 PAM preclinical candidate that resulted in the discovery of VU6005806/AZN-00016130. While the thieno[2,3-c]pyridazine core has been a consistent feature of key M4 PAMs, no work had previously been reported with respect to alternate functionality at the C3 position of the pyridazine ring. Here, we detail new chemistry and analogs that explored this region, and quickly led to VU6005806/AZN-00016130, which was profiled as a putative candidate. While, the ß-amino carboxamide moiety engendered solubility limited absorption in higher species precluding advancement (or requiring extensive pharmaceutical sciences formulation), VU6005806/AZN-00016130 represents a new, high quality preclinical in vivo probe.
Assuntos
Regulação Alostérica/imunologia , Receptor Muscarínico M4/imunologia , Estrutura Molecular , Relação Estrutura-AtividadeRESUMO
This letter describes a focused, multi-dimensional optimization campaign around BL-1249, a fenamate class non-steroidal anti-inflammatory and a known activator of the K2P potassium channels TREK-1 (K2P2.1) and TREK-2 (K2P10.1). While BL-1249 has been widely profiled in vitro as a dual TREK-1/2 activator, poor physicochemical and DMPK properties have precluded a deeper understanding of the therapeutic potential of these key K2P channels across a broad spectrum of peripheral and central human disease. Here, we report multi-dimensional SAR that led to a novel TREK-1/2 dual activator chemotype, exemplified by ONO-2960632/VU6011992, with improved DMPK properties, representing a new lead for further optimization towards robust in vivo tool compounds.
Assuntos
Canais de Potássio de Domínios Poros em Tandem/metabolismo , Tetra-Hidronaftalenos/uso terapêutico , Tetrazóis/uso terapêutico , Humanos , Tetra-Hidronaftalenos/farmacologia , Tetrazóis/farmacologiaRESUMO
The 1,2,3-triazole has been successfully utilized as an amide bioisostere in multiple therapeutic contexts. Based on this precedent, triazole analogues derived from VX-809 and VX-770, prominent amide-containing modulators of the cystic fibrosis transmembrane conductance regulator (CFTR), were synthesized and evaluated for CFTR modulation. Triazole 11, derived from VX-809, displayed markedly reduced efficacy in F508del-CFTR correction in cellular TECC assays in comparison to VX-809. Surprisingly, triazole analogues derived from potentiator VX-770 displayed no potentiation of F508del, G551D, or WT-CFTR in cellular Ussing chamber assays. However, patch clamp analysis revealed that triazole 60 potentiates WT-CFTR similarly to VX-770. The efficacy of 60 in the cell-free patch clamp experiment suggests that the loss of activity in the cellular assay could be due to the inability of VX-770 triazole derivatives to reach the CFTR binding site. Moreover, in addition to the negative impact on biological activity, triazoles in both structural classes displayed decreased metabolic stability in human microsomes relative to the analogous amides. In contrast to the many studies that demonstrate the advantages of using the 1,2,3-triazole, these findings highlight the negative impacts that can arise from replacement of the amide with the triazole and suggest that caution is warranted when considering use of the 1,2,3-triazole as an amide bioisostere.
RESUMO
This letter describes a focused exercise to explore the role of the ß-amino carboxamide moiety found in all of the first generation M4 PAMs and question if the NH2 group served solely to stabilize an intramolecular hydrogen bond (IMHB) and enforce planarity. To address this issue (and to potentially find a substitute for the ß-amino carboxamide that engendered P-gp and contributed to solubility liabilities), we removed the NH2, generating des-amino congeners and surveyed other functional groups in the ß-position. These modifications led to weak M4 PAMs with poor DMPK properties. Cyclization of the ß-amino carboxamide moiety by virtue of a pyrazole ring re-enforced the IMHB, led to potent (and patented) M4 PAMs, many as potent as the classical bicyclic ß-amino carboxamide analogs, but with significant CYP1A2 inhibition. Overall, this exercise indicated that the ß-amino carboxamide moiety most likely facilitates an IMHB, and is essential for M4 PAM activity within classical bicyclic M4 PAM scaffolds.
Assuntos
Amidas/farmacologia , Receptor Muscarínico M4/antagonistas & inibidores , Regulação Alostérica/efeitos dos fármacos , Amidas/síntese química , Amidas/química , Relação Dose-Resposta a Droga , Humanos , Ligação de Hidrogênio , Ligantes , Estrutura Molecular , Receptor Muscarínico M4/metabolismo , Relação Estrutura-AtividadeRESUMO
G protein-gated inwardly rectifying potassium (GIRK) channels are potassium-selective ion channels. As their name suggests, GIRK channels are effectors of Gi/o G protein-couple receptors whereby activation of these GPCRs leads to increased GIRK channel activity resulting in decreased cellular excitability. In this way, GIRK channels play diverse roles in physiology as effectors of Gi/o-coupled GPCRs: peacemaking in the heart rate, modulation of hormone secretion in endocrine tissues, as well as numerous CNS functions including learning, memory, and addiction/reward. Notably, GIRK channels are widely expressed along the spinothalamic tract and are positioned to play roles in both ascending and descending pain pathways. More notably, GIRK channel knockout and knock-down studies have found that GIRK channels play a major role in the action of opioid analgesics which act predominantly through Gi/o-coupled, opioid-activated GPCRs (e.g., µ-opioid receptors). Recent advances in GIRK channel pharmacology have led to the development of small molecules that directly and selectively activate GIRK channels. Based on research implicating the involvement of GIRK channels in pain pathways and as effectors of opioid analgesics, we conducted a study to determine whether direct pharmacological activation of GIRK channels could produce analgesic efficacy and/or augment the analgesic efficacy morphine, an opioid receptor agonist capable of activating µ-opioid receptors as well as other opioid receptor subtypes. In the present study, we demonstrate that the small-molecule GIRK activator, VU0466551, has analgesic effects when dosed alone or in combination with submaximally effective doses of morphine.
Assuntos
Analgésicos/farmacologia , Morfina/farmacologia , Dor/tratamento farmacológico , Compostos de Fenilureia/farmacologia , Pirazóis/farmacologia , Animais , Modelos Animais de Doenças , Relação Dose-Resposta a Droga , Quimioterapia Combinada , Formaldeído , Canais de Potássio Corretores do Fluxo de Internalização Acoplados a Proteínas G/metabolismo , Células HEK293 , Temperatura Alta , Humanos , Masculino , Camundongos Endogâmicos C57BL , Dor/metabolismoRESUMO
Allosteric modulation of GPCRs represents an increasingly explored approach in drug development. Due to complex pharmacology, however, the relationship(s) between modulator properties determined in vitro with in vivo concentration-effect phenomena is frequently unclear. We investigated key pharmacological properties of a set of metabotropic glutamate receptor 5 (mGlu5) positive allosteric modulators (PAMs) and their relevance to in vivo concentration-response relationships. These studies identified a significant relationship between in vitro PAM cooperativity (αß), as well as the maximal response obtained from a simple in vitro PAM concentration-response experiment, with in vivo efficacy for reversal of amphetamine-induced hyperlocomotion. This correlation did not exist with PAM potency or affinity. Data across PAMs were then converged to calculate an in vivo concentration of glutamate putatively relevant to the mGlu5 PAM mechanism of action. This work demonstrates the ability to merge in vitro pharmacology profiles with relevant behavioral outcomes and also provides a novel method to estimate neurotransmitter concentrations in vivo.