RESUMEN
The identification and development of a novel series of small molecule Enhancer of Zeste Homologue 2 (EZH2) inhibitors is described. A concise and modular synthesis enabled the rapid development of structure-activity relationships, which led to the identification of 44 as a potent, SAM-competitive inhibitor of EZH2 that dose-dependently decreased global H3K27me3 in KARPAS-422 lymphoma cells.
RESUMEN
The histone lysine methyltransferase (MT) Enhancer of Zeste Homolog 2 (EZH2) is considered an oncogenic driver in a subset of germinal center B-cell-like diffuse large B cell lymphoma (GCB-DLBCL) and follicular lymphoma due to the presence of recurrent, monoallelic mutations in the EZH2 catalytic domain. These genomic data suggest that targeting the EZH2 MT activity is a valid therapeutic strategy for the treatment of lymphoma patients with EZH2 mutations. Here we report the identification of highly potent and selective EZH2 small molecule inhibitors, their validation by a cellular thermal shift assay, application across a large cell panel representing various non-Hodgkin's lymphoma (NHL) subtypes, and their efficacy in EZH2mutant-containing GCB-DLBCL xenograft models. Surprisingly, our EZH2 inhibitors selectively affect the turnover of trimethylated, but not monomethylated histone H3 lysine 27 at pharmacologically relevant doses. Importantly, we find that these inhibitors are broadly efficacious also in NHL models with wild-type EZH2.
Asunto(s)
Apoptosis/efectos de los fármacos , Inhibidores Enzimáticos/toxicidad , Histonas/metabolismo , Complejo Represivo Polycomb 2/antagonistas & inhibidores , Bibliotecas de Moléculas Pequeñas/toxicidad , Secuencia de Aminoácidos , Animales , Línea Celular Tumoral , Proliferación Celular/efectos de los fármacos , Modelos Animales de Enfermedad , Inhibidores Enzimáticos/química , Inhibidores Enzimáticos/uso terapéutico , Histonas/química , Humanos , Cinética , Linfoma de Células B Grandes Difuso/tratamiento farmacológico , Linfoma de Células B Grandes Difuso/patología , Linfoma no Hodgkin/metabolismo , Linfoma no Hodgkin/patología , Metilación , Ratones , Ratones Desnudos , Mutación , Péptidos/análisis , Complejo Represivo Polycomb 2/genética , Complejo Represivo Polycomb 2/metabolismo , Bibliotecas de Moléculas Pequeñas/química , Bibliotecas de Moléculas Pequeñas/uso terapéutico , Trasplante HeterólogoRESUMEN
The histone methyltransferase enhancer of Zeste homolog 2 (EZH2) is a candidate oncogene due to its prevalent overexpression in malignant diseases, including late stage prostate and breast cancers. The dependency of cancer cells on EZH2 activity is also predicated by recurrent missense mutations residing in the catalytic domain of EZH2 that have been identified in subtypes of diffuse large B cell lymphoma, follicular lymphoma and melanoma. Herein, we report the identification of a highly selective small molecule inhibitor series of EZH2 and EZH1. These compounds inhibit wild-type and mutant versions of EZH2 with nanomolar potency, suppress global histone H3-lysine 27 methylation, affect gene expression, and cause selective proliferation defects. These compounds represent a structurally distinct EZH2 inhibitor chemotype for the exploration of the role of Polycomb Repressive Complex 2-mediated H3K27 methylation in various biological contexts.