RESUMO
PI3K-δ mediates key immune cell signaling pathways and is a target of interest for treatment of oncological and immunological disorders. Here we describe the discovery and optimization of a novel series of PI3K-δ selective inhibitors. We first identified hits containing an isoindolinone scaffold using a combined ligand- and receptor-based virtual screening workflow, and then improved potency and selectivity guided by structural data and modeling. Careful optimization of molecular properties led to compounds with improved permeability and pharmacokinetic profile, and high potency in a whole blood assay.
Assuntos
Classe I de Fosfatidilinositol 3-Quinases/antagonistas & inibidores , Descoberta de Drogas , Inibidores de Fosfoinositídeo-3 Quinase/farmacologia , Ftalimidas/farmacologia , Classe I de Fosfatidilinositol 3-Quinases/metabolismo , Relação Dose-Resposta a Droga , Avaliação Pré-Clínica de Medicamentos , Humanos , Estrutura Molecular , Inibidores de Fosfoinositídeo-3 Quinase/síntese química , Inibidores de Fosfoinositídeo-3 Quinase/química , Ftalimidas/síntese química , Ftalimidas/química , Relação Estrutura-AtividadeRESUMO
PRDM9 is a PR domain containing protein which trimethylates histone 3 on lysine 4 and 36. Its normal expression is restricted to germ cells and attenuation of its activity results in altered meiotic gene transcription, impairment of double-stranded breaks and pairing between homologous chromosomes. There is growing evidence for a role of aberrant expression of PRDM9 in oncogenesis and genome instability. Here we report the discovery of MRK-740, a potent (IC50: 80 ± 16 nM), selective and cell-active PRDM9 inhibitor (Chemical Probe). MRK-740 binds in the substrate-binding pocket, with unusually extensive interactions with the cofactor S-adenosylmethionine (SAM), conferring SAM-dependent substrate-competitive inhibition. In cells, MRK-740 specifically and directly inhibits H3K4 methylation at endogenous PRDM9 target loci, whereas the closely related inactive control compound, MRK-740-NC, does not. The discovery of MRK-740 as a chemical probe for the PRDM subfamily of methyltransferases highlights the potential for exploiting SAM in targeting SAM-dependent methyltransferases.
Assuntos
Descoberta de Drogas/métodos , Inibidores Enzimáticos/farmacologia , Histona-Lisina N-Metiltransferase/antagonistas & inibidores , Sondas Moleculares/farmacologia , Cristalografia por Raios X , Metilação de DNA/efeitos dos fármacos , Inibidores Enzimáticos/química , Células HEK293 , Histona-Lisina N-Metiltransferase/metabolismo , Histona-Lisina N-Metiltransferase/ultraestrutura , Histonas/metabolismo , Humanos , Concentração Inibidora 50 , Simulação de Dinâmica Molecular , Sondas Moleculares/química , Domínios Proteicos , S-Adenosilmetionina/metabolismoRESUMO
The successful application of both solid and solution phase library synthesis, combined with tight integration into the medicinal chemistry effort, resulted in the efficient optimization of a novel structural series of selective HDAC1/HDAC2 inhibitors by the MRL-Boston Parallel Medicinal Chemistry group. An initial lead from a small parallel library was found to be potent and selective in biochemical assays. Advanced compounds were the culmination of iterative library design and possess excellent biochemical and cellular potency, as well as acceptable PK and efficacy in animal models.