RESUMO
The bromodomain and extra terminal (BET) family of bromodomain-containing proteins are important epigenetic regulators that elicit their effect through binding histone tail N-acetyl lysine (KAc) post-translational modifications. Recognition of such markers has been implicated in a range of oncology and immune diseases and, as such, small-molecule inhibition of the BET family bromodomain-KAc protein-protein interaction has received significant interest as a therapeutic strategy, with several potential medicines under clinical evaluation. This work describes the structure- and property-based optimization of a ligand and lipophilic efficient pan-BET bromodomain inhibitor series to deliver candidate I-BET787 (70) that demonstrates efficacy in a mouse model of inflammation and suitable properties for both oral and intravenous (IV) administration. This focused two-phase explore-exploit medicinal chemistry effort delivered the candidate molecule in 3 months with less than 100 final compounds synthesized.
Assuntos
Administração Intravenosa , Animais , Administração Oral , Camundongos , Relação Estrutura-Atividade , Humanos , Fatores de Transcrição/antagonistas & inibidores , Fatores de Transcrição/metabolismo , Estrutura MolecularRESUMO
The bromodomain and extra terminal (BET) family of proteins are an integral part of human epigenome regulation, the dysregulation of which is implicated in multiple oncology and inflammatory diseases. Disrupting the BET family bromodomain acetyl-lysine (KAc) histone protein-protein interaction with small-molecule KAc mimetics has proven to be a disease-relevant mechanism of action, and multiple molecules are currently undergoing oncology clinical trials. This work describes an efficiency analysis of published GSK pan-BET bromodomain inhibitors, which drove a strategic choice to focus on the identification of a ligand-efficient KAc mimetic with the hypothesis that lipophilic efficiency could be drastically improved during optimization. This focus drove the discovery of the highly ligand-efficient and structurally distinct benzoazepinone KAc mimetic. Following crystallography to identify suitable growth vectors, the benzoazepinone core was optimized through an explore-exploit structure-activity relationship (SAR) approach while carefully monitoring lipophilic efficiency to deliver I-BET432 (41) as an oral candidate quality molecule.
Assuntos
Lisina , Fatores de Transcrição , Humanos , Lisina/metabolismo , Ligantes , Domínios Proteicos , Histonas/metabolismoRESUMO
Through regulation of the epigenome, the bromodomain and extra terminal (BET) family of proteins represent important therapeutic targets for the treatment of human disease. Through mimicking the endogenous N-acetyl-lysine group and disrupting the protein-protein interaction between histone tails and the bromodomain, several small molecule pan-BET inhibitors have progressed to oncology clinical trials. This work describes the medicinal chemistry strategy and execution to deliver an orally bioavailable tetrahydroquinoline (THQ) pan-BET candidate. Critical to the success of this endeavor was a potency agnostic analysis of a data set of 1999 THQ BET inhibitors within the GSK collection which enabled identification of appropriate lipophilicity space to deliver compounds with a higher probability of desired oral candidate quality properties. SAR knowledge was leveraged via Free-Wilson analysis within this design space to identify a small group of targets which ultimately delivered I-BET567 (27), a pan-BET candidate inhibitor that demonstrated efficacy in mouse models of oncology and inflammation.
Assuntos
Aminoquinolinas/química , Desenho de Fármacos , Proteínas/metabolismo , Administração Oral , Aminoquinolinas/metabolismo , Aminoquinolinas/farmacocinética , Aminoquinolinas/uso terapêutico , Animais , Benzoatos/química , Benzoatos/metabolismo , Sítios de Ligação , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Cristalografia por Raios X , Cães , Meia-Vida , Humanos , Masculino , Camundongos , Conformação Molecular , Simulação de Dinâmica Molecular , Neoplasias/tratamento farmacológico , Proteínas/antagonistas & inibidores , Ratos , Relação Estrutura-AtividadeRESUMO
Pan-BET inhibitors have shown profound efficacy in a number of in vivo preclinical models and have entered the clinic in oncology trials where adverse events have been reported. These inhibitors interact equipotently with the eight bromodomains of the BET family of proteins. To better understand the contribution of each domain to their efficacy and to improve from their safety profile, selective inhibitors are required. This Letter discloses the profile of GSK973, a highly selective inhibitor of the second bromodomains of the BET proteins that has undergone extensive preclinical in vitro and in vivo characterization.
RESUMO
Malfunctions in the basic epigenetic mechanisms such as histone modifications, DNA methylation, and chromatin remodeling are implicated in a number of cancers and immunological and neurodegenerative conditions. Within GlaxoSmithKline (GSK) we have utilized a number of variations of the NanoBRET technology for the direct measurement of compound-target engagement within native cellular environments to drive high-throughput, routine structure-activity relationship (SAR) profiling across differing epigenetic targets. NanoBRET is a variation of the bioluminescence resonance energy transfer (BRET) methodology utilizing proteins of interest fused to either NanoLuc, a small, high-emission-intensity luciferase, or HaloTag, a modified dehalogenase enzyme that can be selectively labeled with a fluorophore. The combination of these two technologies has enabled the application of NanoBRET to biological systems such as epigenetic protein-protein interactions, which have previously been challenging. By synergizing target engagement assays with more complex primary cell phenotypic assays, we have been able to demonstrate compound-target selectivity profiles to enhance cellular potency and offset potential liability risks. Additionally, we have shown that in the absence of a robust, cell phenotypic assay, it is possible to utilize NanoBRET target engagement assays to aid chemistry in progressing at a higher scale than would have otherwise been achievable. The NanoBRET target engagement assays utilized have further shown an excellent correlation with more reductionist biochemical and biophysical assay systems, clearly demonstrating the possibility of using such assay systems at scale, in tandem with, or in preference to, lower-throughput cell phenotypic approaches.
Assuntos
Bioensaio , Epigênese Genética/genética , Relação Estrutura-Atividade , Montagem e Desmontagem da Cromatina/genética , Metilação de DNA/genética , Transferência Ressonante de Energia de Fluorescência , Código das Histonas/genética , Humanos , Luciferases/químicaRESUMO
The bromodomain and extra-terminal domain (BET) family of proteins bind acetylated lysine residues on histone proteins. The four BET bromodomains-BRD2, BRD3, BRD4, and BRDT-each contain two bromodomain modules. BET bromodomain inhibition is a potential therapy for various cancers and immunoinflammatory diseases, but few reported inhibitors show selectivity within the BET family. Inhibitors with selectivity for the first or second bromodomain are desired to aid investigation of the biological function of these domains. Focused library screening identified a series of tetrahydroquinoxalines with selectivity for the second bromodomains of the BET family (BD2). Structure-guided optimization of the template improved potency, selectivity, and physicochemical properties, culminating in potent BET inhibitors with BD2 selectivity.
Assuntos
Descoberta de Drogas , Proteínas Nucleares/antagonistas & inibidores , Domínios e Motivos de Interação entre Proteínas , Proteínas Serina-Treonina Quinases/antagonistas & inibidores , Quinoxalinas/química , Quinoxalinas/farmacologia , Fatores de Transcrição/antagonistas & inibidores , Sequência de Aminoácidos , Sítios de Ligação , Proteínas de Ciclo Celular , Humanos , Modelos Moleculares , Simulação de Dinâmica Molecular , Estrutura Molecular , Ligação Proteica , Conformação Proteica , Relação Quantitativa Estrutura-Atividade , Homologia de SequênciaRESUMO
Inadequate target exposure is a major cause of high attrition in drug discovery. Here, we show that a label-free method for quantifying the intracellular bioavailability (Fic) of drug molecules predicts drug access to intracellular targets and hence, pharmacological effect. We determined Fic in multiple cellular assays and cell types representing different targets from a number of therapeutic areas, including cancer, inflammation, and dementia. Both cytosolic targets and targets localized in subcellular compartments were investigated. Fic gives insights on membrane-permeable compounds in terms of cellular potency and intracellular target engagement, compared with biochemical potency measurements alone. Knowledge of the amount of drug that is locally available to bind intracellular targets provides a powerful tool for compound selection in early drug discovery.
Assuntos
Descoberta de Drogas/métodos , Secretases da Proteína Precursora do Amiloide/antagonistas & inibidores , Ácido Aspártico Endopeptidases/antagonistas & inibidores , Disponibilidade Biológica , Transporte Biológico , Células HEK293 , Células HL-60 , Humanos , Proteína Quinase 14 Ativada por Mitógeno/antagonistas & inibidores , Inibidores de Proteases/farmacocinética , Inibidores de Proteínas Quinases/farmacocinéticaRESUMO
One of the key challenges facing early stage drug discovery is understanding the commonly observed difference between the activity of compounds in biochemical assays and cellular assays. Traditionally, indirect or estimated cell permeability measurements such as estimations from logP or artificial membrane permeability are used to explain the differences. The missing link is a direct measurement of intracellular compound concentration in whole cells. This can, in some circumstances, be estimated from the cellular activity, but this may also be problematic if cellular activity is weak or absent. Advances in sensitivity and throughput of analytical techniques have enabled us to develop a high-throughput assay for the measurement of intracellular compound concentration for routine use to support lead optimization. The assay uses a RapidFire-MS based readout of compound concentration in HeLa cells following incubation of cells with test compound. The initial assay validation was performed by ultra-high performance liquid chromatography tandem mass spectrometry, and the assay was subsequently transferred to RapidFire tandem mass spectrometry. Further miniaturization and optimization were performed to streamline the process, increase sample throughput, and reduce cycle time. This optimization has delivered a semi-automated platform with the potential of production scale compound profiling up to 100 compounds per day.
Assuntos
Preparações Farmacêuticas/química , Preparações Farmacêuticas/metabolismo , Linhagem Celular Tumoral , Cromatografia Líquida , Descoberta de Drogas/métodos , Células HeLa , Ensaios de Triagem em Larga Escala/métodos , Humanos , Permeabilidade , Espectrometria de Massas em Tandem/métodosRESUMO
Bioisoteric replacement of the metabolically labile N-methyl amide group of a series of benzoxazinones with small heterocyclic rings has led to novel series of fused tricyclic benzoxazines which are potent 5-HT(1A/B/D) receptor antagonists with and without concomitant human serotonin transporter (hSerT) activity. Optimizing against multiple parameters in parallel identified 6-{2-[4-(2-methyl-5-quinolinyl)-1-piperazinyl]ethyl}-4H-imidazo[5,1-c][1,4]benzoxazine-3-carboxamide (GSK588045) as a potent 5-HT(1A/B/D) receptor antagonist with a high degree of selectivity over human ether-a-go-go related gene (hERG) potassium channels, favorable pharmacokinetics, and excellent activity in vivo in rodent pharmacodynamic (PD) models. On the basis of its outstanding overall profile, this compound was progressed as a clinical candidate with the ultimate aim to assess its potential as a faster acting antidepressant/anxiolytic with reduced side-effect burden.
Assuntos
Ansiolíticos/síntese química , Antidepressivos/síntese química , Benzoxazinas/síntese química , Antagonistas do Receptor 5-HT1 de Serotonina , Animais , Ansiolíticos/farmacocinética , Ansiolíticos/farmacologia , Antidepressivos/farmacocinética , Antidepressivos/farmacologia , Benzoxazinas/farmacocinética , Benzoxazinas/farmacologia , Callithrix , Linhagem Celular , Córtex Cerebral/metabolismo , Cricetinae , Cricetulus , Sistema Enzimático do Citocromo P-450/metabolismo , Canal de Potássio ERG1 , Canais de Potássio Éter-A-Go-Go/metabolismo , Cobaias , Humanos , Técnicas In Vitro , Masculino , Microssomos Hepáticos/metabolismo , Ligação Proteica , Ensaio Radioligante , Ratos , Ratos Sprague-Dawley , Proteínas da Membrana Plasmática de Transporte de Serotonina/metabolismo , Relação Estrutura-AtividadeRESUMO
8-[2-(4-Aryl-1-piperazinyl)ethyl]-2H-1,4-benzoxazin-3(4H)-ones have been identified as highly potent 5-HT(1A/B/D) receptor antagonists with and without additional SerT activity and a high degree of selectivity over hERG potassium channels. Modulation of the different target activities gave compounds with a range of profiles suitable for further in vivo characterization.