RESUMO
The recent publication of a potent and selective inhibitor of protein methyltransferase 5 (PRMT5) provides the scientific community with in vivo-active tool compound EPZ015666 (GSK3235025) to probe the underlying pharmacology of this key enzyme. Herein, we report the design and optimization strategies employed on an initial hit compound with poor in vitro clearance to yield in vivo tool compound EPZ015666 and an additional potent in vitro tool molecule EPZ015866 (GSK3203591).
RESUMO
Protein arginine methyltransferase-5 (PRMT5) is reported to have a role in diverse cellular processes, including tumorigenesis, and its overexpression is observed in cell lines and primary patient samples derived from lymphomas, particularly mantle cell lymphoma (MCL). Here we describe the identification and characterization of a potent and selective inhibitor of PRMT5 with antiproliferative effects in both in vitro and in vivo models of MCL. EPZ015666 (GSK3235025) is an orally available inhibitor of PRMT5 enzymatic activity in biochemical assays with a half-maximal inhibitory concentration (IC50) of 22 nM and broad selectivity against a panel of other histone methyltransferases. Treatment of MCL cell lines with EPZ015666 led to inhibition of SmD3 methylation and cell death, with IC50 values in the nanomolar range. Oral dosing with EPZ015666 demonstrated dose-dependent antitumor activity in multiple MCL xenograft models. EPZ015666 represents a validated chemical probe for further study of PRMT5 biology and arginine methylation in cancer and other diseases.
Assuntos
Antineoplásicos/farmacologia , Isoquinolinas/farmacologia , Linfoma de Célula do Manto/patologia , Proteína-Arginina N-Metiltransferases/antagonistas & inibidores , Pirimidinas/farmacologia , Animais , Antineoplásicos/química , Antineoplásicos/uso terapêutico , Morte Celular/efeitos dos fármacos , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Cristalografia por Raios X , Relação Dose-Resposta a Droga , Humanos , Concentração Inibidora 50 , Isoquinolinas/química , Isoquinolinas/uso terapêutico , Linfoma de Célula do Manto/tratamento farmacológico , Linfoma de Célula do Manto/enzimologia , Masculino , Metilação , Camundongos Endogâmicos , Modelos Moleculares , Estrutura Molecular , Ligação Proteica , Pirimidinas/química , Pirimidinas/uso terapêutico , Ensaios Antitumorais Modelo de Xenoenxerto , Proteínas Centrais de snRNP/metabolismoRESUMO
Calsenilin/potassium channel-interacting protein (KChIP)3/ downstream regulatory element sequence antagonist modulator (DREAM) is a neuronal calcium-binding protein that has been shown to have multiple functions in the cell, including the regulation of presenilin processing, repression of transcription and modulation of A-type potassium channels. To gain a better understanding of the precise role of calsenilin in specific cellular compartments, an interactor hunt for proteins that bind to the N-terminal domain of calsenilin was carried out. Using a yeast two-hybrid system and co-immunoprecipitation studies, we have identified the transcriptional co-repressor C-terminal binding protein (CtBP)2 as an interactor for calsenilin and have shown that the two proteins can interact in vivo. In co-immunoprecipitation studies, calsenilin also interacted with CtBP1, a CtBP2 homolog. Our data also showed a calsenilin-dependent increase in c-fos protein levels in CtBP knockout fibroblasts, suggesting that CtBP may modulate the transcriptional repression of c-fos by calsenilin. Furthermore, the finding that histone deacetylase protein and activity were associated with the calsenilin-CtBP immunocomplex suggests a mechanism by which calsenilin-CtBP may act to repress transcription. Finally, we demonstrated that calsenilin and CtBP are present in synaptic vesicles and can interact in vivo.
