RESUMO
c-Abl kinase is maintained in its normal inactive state in the cell through an assembled, compact conformation. We describe two chemical series that bind to the myristoyl site of the c-Abl kinase domain and stimulate c-Abl activation. We hypothesize that these molecules activate c-Abl either by blocking the C-terminal helix from adopting a bent conformation that is critical for the formation of the autoinhibited conformation or by simply providing no stabilizing interactions to the bent conformation of this helix. Structure-based molecular modeling guided the optimization of binding and activation of c-Abl of these two chemical series and led to the discovery of c-Abl activators with nanomolar potency. The small molecule c-Abl activators reported herein could be used as molecular tools to investigate the biological functions of c-Abl and therapeutic implications of its activation.
Assuntos
Modelos Moleculares , Proteínas Proto-Oncogênicas c-abl/metabolismo , Bibliotecas de Moléculas Pequenas/farmacologia , Sítios de Ligação , Cristalografia por Raios X , Interações Hidrofóbicas e Hidrofílicas , Conformação Proteica , Estrutura Terciária de Proteína , Proteínas Proto-Oncogênicas c-abl/química , Pirazóis/química , Bibliotecas de Moléculas Pequenas/metabolismo , Relação Estrutura-AtividadeRESUMO
The SAR around a V1b antagonist HTS hit 3 was explored to produce a series of thiazole sulfonamides as a lead series with selectivity over the related V1 and oxytocin receptors.
Assuntos
Antagonistas dos Receptores de Hormônios Antidiuréticos , Sulfonamidas/química , Animais , Ensaios de Triagem em Larga Escala , Ratos , Receptores de Ocitocina/antagonistas & inibidores , Receptores de Ocitocina/metabolismo , Receptores de Vasopressinas/metabolismo , Relação Estrutura-Atividade , Tiazóis/químicaRESUMO
Decaprenylphosphoryl-ß-d-ribose 2'-epimerase (DprE1) is an essential enzyme in Mycobacterium tuberculosis and has recently been studied as a potential drug target, with inhibitors progressing to clinical studies. Here we describe the identification of a novel series of morpholino-pyrimidine DprE1 inhibitors. These were derived from a phenotypic high-throughput screening (HTS) hit with suboptimal physicochemical properties. Optimization strategies included scaffold-hopping, synthesis, and evaluation of fragments of the lead compounds and property-focused optimization. The resulting optimized compounds had much improved physicochemical properties and maintained enzyme and cellular potency. These molecules demonstrated potent efficacy in an in vivo tuberculosis murine infection model.
Assuntos
Oxirredutases do Álcool/antagonistas & inibidores , Antituberculosos/farmacologia , Proteínas de Bactérias/antagonistas & inibidores , Inibidores Enzimáticos/farmacologia , Mycobacterium tuberculosis/efeitos dos fármacos , Pirimidinas/farmacologia , Tuberculose/tratamento farmacológico , Oxirredutases do Álcool/metabolismo , Animais , Antituberculosos/química , Antituberculosos/uso terapêutico , Proteínas de Bactérias/metabolismo , Inibidores Enzimáticos/química , Inibidores Enzimáticos/uso terapêutico , Humanos , Masculino , Camundongos , Morfolinas/química , Morfolinas/farmacologia , Morfolinas/uso terapêutico , Mycobacterium tuberculosis/enzimologia , Pirimidinas/química , Pirimidinas/uso terapêutico , Tuberculose/microbiologiaRESUMO
Abelson kinase (c-Abl) is a ubiquitously expressed, nonreceptor tyrosine kinase which plays a key role in cell differentiation and survival. It was hypothesized that transient activation of c-Abl kinase via displacement of the N-terminal autoinhibitory "myristoyl latch", may lead to an increased hematopoietic stem cell differentiation. This would increase the numbers of circulating neutrophils and so be an effective treatment for chemotherapy-induced neutropenia. This paper describes the discovery and optimization of a thiazole series of novel small molecule c-Abl activators, initially identified by a high throughput screening. Subsequently, a scaffold-hop, which exploited the improved physicochemical properties of a dihydropyrazole analogue, identified through fragment screening, delivered potent, soluble, cell-active c-Abl activators, which demonstrated the intracellular activation of c-Abl in vivo.
Assuntos
Inibidores de Proteínas Quinases/farmacologia , Proteínas Proto-Oncogênicas c-abl/antagonistas & inibidores , Pirazóis/farmacologia , Tiazóis/farmacologia , Animais , Sítios de Ligação , Descoberta de Drogas , Ensaios de Triagem em Larga Escala , Humanos , Camundongos , Estrutura Molecular , Ligação Proteica , Inibidores de Proteínas Quinases/química , Inibidores de Proteínas Quinases/metabolismo , Proteínas Proto-Oncogênicas c-abl/química , Proteínas Proto-Oncogênicas c-abl/metabolismo , Pirazóis/química , Pirazóis/metabolismo , Relação Estrutura-Atividade , Tiazóis/química , Tiazóis/metabolismoRESUMO
Inhibitors of mitochondrial branched chain aminotransferase (BCATm), identified using fragment screening, are described. This was carried out using a combination of STD-NMR, thermal melt (Tm), and biochemical assays to identify compounds that bound to BCATm, which were subsequently progressed to X-ray crystallography, where a number of exemplars showed significant diversity in their binding modes. The hits identified were supplemented by searching and screening of additional analogues, which enabled the gathering of further X-ray data where the original hits had not produced liganded structures. The fragment hits were optimized using structure-based design, with some transfer of information between series, which enabled the identification of ligand efficient lead molecules with micromolar levels of inhibition, cellular activity, and good solubility.
Assuntos
Mitocôndrias/enzimologia , Transaminases/antagonistas & inibidores , Adipócitos/efeitos dos fármacos , Adipócitos/enzimologia , Cristalografia por Raios X , Ensaios de Triagem em Larga Escala , Humanos , Espectroscopia de Ressonância Magnética , Modelos Moleculares , Fragmentos de Peptídeos/química , Fragmentos de Peptídeos/farmacologia , Ligação Proteica , Relação Estrutura-AtividadeRESUMO
The hybridization of hits, identified by complementary fragment and high throughput screens, enabled the discovery of the first series of potent inhibitors of mitochondrial branched-chain aminotransferase (BCATm) based on a 2-benzylamino-pyrazolo[1,5-a]pyrimidinone-3-carbonitrile template. Structure-guided growth enabled rapid optimization of potency with maintenance of ligand efficiency, while the focus on physicochemical properties delivered compounds with excellent pharmacokinetic exposure that enabled a proof of concept experiment in mice. Oral administration of 2-((4-chloro-2,6-difluorobenzyl)amino)-7-oxo-5-propyl-4,7-dihydropyrazolo[1,5-a]pyrimidine-3-carbonitrile 61 significantly raised the circulating levels of the branched-chain amino acids leucine, isoleucine, and valine in this acute study.