RESUMEN
[This corrects the article DOI: 10.1021/acsmedchemlett.7b00126.].
RESUMEN
Histone deacetylase (HDAC) activity is modulated inâ vivo by post-translational modifications and formation of multiprotein complexes. Novel chemical tools to study how these factors affect engagement of HDAC isoforms by HDAC inhibitors (HDACi) in cells and tissues are needed. In this study, a synthetic strategy to access chemically diverse photoreactive probes (PRPs) was developed and used to prepare seven novel HDAC PRPs 9-15. The classâ I HDAC isoform engagement by PRPs was determined in biochemical assays and photolabeling experiments in live SET-2, HepG2, HuH7, and HEK293T cell lines and in mouse liver tissue. Unlike the HDAC protein abundance and biochemical activity against recombinant HDACs, the chemotype of the PRPs and the type of cells were key in defining the engagement of HDAC isoforms in live cells. Our findings suggest that engagement of HDAC isoforms by HDACi inâ vivo may be substantially modulated in a cell- and tissue-type-dependent manner.
Asunto(s)
Diseño de Fármacos , Colorantes Fluorescentes/farmacología , Inhibidores de Histona Desacetilasas/farmacología , Histona Desacetilasas/metabolismo , Imagen Óptica , Etiquetas de Fotoafinidad/farmacología , Animales , Células Cultivadas , Colorantes Fluorescentes/síntesis química , Colorantes Fluorescentes/química , Inhibidores de Histona Desacetilasas/síntesis química , Inhibidores de Histona Desacetilasas/química , Humanos , Isoenzimas/antagonistas & inhibidores , Isoenzimas/metabolismo , Hígado/diagnóstico por imagen , Ratones , Ratones de la Cepa 129 , Etiquetas de Fotoafinidad/síntesis química , Etiquetas de Fotoafinidad/químicaRESUMEN
Histone deacetylase 8 (HDAC8) is a promising drug target for multiple therapeutic applications. Here, we describe the modeling, design, synthesis, and biological evaluation of a novel series of C1-substituted tetrahydroisoquinoline (TIQ)-based HDAC8 inhibitors. Minimization of entropic loss upon ligand binding and use of the unique HDAC8 "open" conformation of the binding site yielded a successful strategy for improvement of both HDAC8 potency and selectivity. The TIQ-based 3g and 3n exhibited the highest 82 and 55 nM HDAC8 potency and 330- and 135-fold selectivity over HDAC1, respectively. Selectivity over other class I isoforms was comparable or better, whereas inhibition of HDAC6, a class II HDAC isoform, was below 50% at 10 µM. The cytotoxicity of 3g and 3n was evaluated in neuroblastoma cell lines, and 3n displayed concentration-dependent cytotoxicity similar to or better than that of PCI-34051. The selectivity of 3g and 3n was confirmed in SH-SY5Y cells as both did not increase the acetylation of histone H3 and α-tubulin. Discovery of the novel TIQ chemotype paves the way for the development of HDAC8 selective inhibitors for therapeutic applications.