RESUMO
The voltage-gated sodium channel Nav1.7 is an attractive target for the treatment of pain based on the high level of target validation with genetic evidence linking Nav1.7 to pain in humans. Our effort to identify selective, CNS-penetrant Nav1.7 blockers with oral activity, improved selectivity, good drug-like properties, and safety led to the discovery of 2-substituted quinolines and quinolones as potent small molecule Nav1.7 blockers. The design of these molecules focused on maintaining potency at Nav1.7, improving selectivity over the hERG channel, and overcoming phospholipidosis observed with the initial leads. The structure-activity relationship (SAR) studies leading to the discovery of (R)-(3-fluoropyrrolidin-1-yl)(6-((5-(trifluoromethyl)pyridin-2-yl)oxy)quinolin-2-yl)methanone (ABBV-318) are described herein. ABBV-318 displayed robust in vivo efficacy in both inflammatory and neuropathic rodent models of pain. ABBV-318 also inhibited Nav1.8, another sodium channel isoform that is an active target for the development of new pain treatments.
Assuntos
Dor , Canais de Sódio , Humanos , Dor/tratamento farmacológico , Manejo da Dor , Isoformas de Proteínas , Canais de Sódio/metabolismo , Relação Estrutura-AtividadeRESUMO
The genetic validation for the role of the Nav1.7 voltage-gated ion channel in pain signaling pathways makes it an appealing target for the potential development of new pain drugs. The utility of nonselective Nav blockers is often limited due to adverse cardiovascular and CNS side effects. We sought more selective Nav1.7 blockers with oral activity, improved selectivity, and good druglike properties. The work described herein focused on a series of 3- and 4-substituted indazoles. SAR studies of 3-substituted indazoles yielded analog 7 which demonstrated good in vitro and in vivo activity but poor rat pharmacokinetics. Optimization of 4-substituted indazoles yielded two compounds, 27 and 48, that exhibited good in vitro and in vivo activity with improved rat pharmacokinetic profiles. Both 27 and 48 demonstrated robust activity in the acute rat monoiodoacetate-induced osteoarthritis model of pain, and subchronic dosing of 48 showed a shift to a lower EC50 over 7 days.
Assuntos
Analgésicos/farmacologia , Imidazolidinas/farmacologia , Indazóis/farmacologia , Canal de Sódio Disparado por Voltagem NAV1.7/química , Osteoartrite/tratamento farmacológico , Dor/tratamento farmacológico , Pirróis/farmacologia , Bloqueadores dos Canais de Sódio/farmacologia , Analgésicos/química , Animais , Modelos Animais de Doenças , Relação Dose-Resposta a Droga , Eletrofisiologia , Potenciais Evocados , Imidazolidinas/química , Indazóis/química , Ácido Iodoacético/toxicidade , Estrutura Molecular , Canal de Sódio Disparado por Voltagem NAV1.7/metabolismo , Osteoartrite/induzido quimicamente , Osteoartrite/metabolismo , Dor/metabolismo , Dor/patologia , Medição da Dor , Pirróis/química , Ratos , Bloqueadores dos Canais de Sódio/química , Relação Estrutura-AtividadeRESUMO
Bridging integrator 1 (BIN1) is a nucleocytoplasmic adaptor protein with tumor suppressor properties. The protein interacts with and inhibits the c-MYC transcription factor through the BIN1 MYC-binding domain (MBD). However, in vitro colony formation assays have clearly demonstrated that the MBD is not essential for BIN1-mediated growth arrest. We hypothesized that BIN1 contains a MYC-independent effector domain (MID) for cancer suppression. Because a functionally unique domain frequently contains a distinct structure, the human full-length BIN1 protein was subjected to limited trypsin digestion and the digested peptides were analyzed with Edman sequencing and mass spectrometry. We identified a trypsin-resistant peptide that corresponds to amino acids 146-268 of BIN1. It encompassed part of the BAR region, a putative effector region of BIN1. Computational analysis predicted that the peptide is very likely to exhibit coiled-coil motifs, implying a potential role for this region in sustaining the BIN1 structure and function. Like MBD-deleted BIN1, the trypsin-resistant peptide of BIN1 was predominantly present in the cytoplasm and was sufficient to inhibit cancer growth, regardless of dysregulated c-MYC activity. Our results suggest that the coiled-coil BIN1 BAR peptide encodes a novel BIN1 MID domain, through which BIN1 acts as a MYC-independent cancer suppressor.
Assuntos
Proteínas Adaptadoras de Transdução de Sinal/química , Proteínas Adaptadoras de Transdução de Sinal/metabolismo , Neoplasias/metabolismo , Proteínas Nucleares/química , Proteínas Nucleares/metabolismo , Proteínas Supressoras de Tumor/química , Proteínas Supressoras de Tumor/metabolismo , Proteínas Adaptadoras de Transdução de Sinal/genética , Linhagem Celular , Humanos , Espectrometria de Massas , Proteínas Nucleares/genética , Isoformas de Proteínas/genética , Isoformas de Proteínas/metabolismo , Estrutura Terciária de Proteína , Tripsina/metabolismo , Proteínas Supressoras de Tumor/genéticaRESUMO
Class IIa histone deacetylases (HDACs) -4, -5, -7 and -9 undergo signal-dependent nuclear export upon phosphorylation of conserved serine residues that are targets for 14-3-3 binding. Little is known of other mechanisms for regulating the subcellular distribution of class IIa HDACs. Using a biochemical purification strategy, we identified protein kinase C-related kinase-2 (PRK2) as an HDAC5-interacting protein. PRK2 and the related kinase, PRK1, phosphorylate HDAC5 at a threonine residue (Thr-292) positioned within the nuclear localization signal (NLS) of the protein. HDAC7 and HDAC9 contain analogous sites that are phosphorylated by PRK, while HDAC4 harbors a non-phosphorylatable alanine residue at this position. We provide evidence to suggest that the unique phospho-acceptor cooperates with the 14-3-3 target sites to impair HDAC nuclear import.
