RESUMO
Epigenetic mechanisms of gene regulation have a profound role in normal development and disease processes. An integral part of this mechanism occurs through lysine acetylation of histone tails which are recognized by bromodomains. While the biological and structural characterization of many bromodomain containing proteins has advanced considerably, the therapeutic tractability of this protein family is only now becoming understood. This paper describes the discovery and molecular characterization of potent (nM) small molecule inhibitors that disrupt the function of the BET family of bromodomains (Brd2, Brd3, and Brd4). By using a combination of phenotypic screening, chemoproteomics, and biophysical studies, we have discovered that the protein-protein interactions between bromodomains and acetylated histones can be antagonized by selective small molecules that bind at the acetylated lysine recognition pocket. X-ray crystal structures of compounds bound into bromodomains of Brd2 and Brd4 elucidate the molecular interactions of binding and explain the precisely defined stereochemistry required for activity.
Assuntos
Apolipoproteína A-I/genética , Benzodiazepinas/metabolismo , Benzodiazepinas/farmacologia , Proteínas Serina-Treonina Quinases/antagonistas & inibidores , Proteínas Serina-Treonina Quinases/química , Acetilação , Sequência de Aminoácidos , Apolipoproteína A-I/química , Apolipoproteína A-I/metabolismo , Benzodiazepinas/síntese química , Benzodiazepinas/química , Sítios de Ligação , Cristalografia por Raios X , Descoberta de Drogas , Epigenômica , Células Hep G2 , Histonas/química , Histonas/genética , Histonas/metabolismo , Humanos , Lisina/química , Lisina/genética , Lisina/metabolismo , Modelos Moleculares , Dados de Sequência Molecular , Estrutura Molecular , Terapia de Alvo Molecular , Ligação Proteica , Proteínas Serina-Treonina Quinases/metabolismo , Estereoisomerismo , Fatores de Transcrição , Regulação para CimaRESUMO
The peroxisome proliferator activated receptors PPARalpha, PPARgamma, and PPARdelta are ligand-activated transcription factors that play a key role in lipid homeostasis. The fibrates raise circulating levels of high-density lipoprotein cholesterol and lower levels of triglycerides in part through their activity as PPARalpha agonists; however, the low potency and restricted selectivity of the fibrates may limit their efficacy, and it would be desirable to develop more potent and selective PPARalpha agonists. Modification of the selective PPARdelta agonist 1 (GW501516) so as to incorporate the 2-aryl-2-methylpropionic acid group of the fibrates led to a marked shift in potency and selectivity toward PPARalpha agonism. Optimization of the series gave 25a, which shows EC50 = 4 nM on PPARalpha and at least 500-fold selectivity versus PPARdelta and PPARgamma. Compound 25a (GW590735) has been progressed to clinical trials for the treatment of diseases of lipid imbalance.
