RESUMEN
The p300/CBP-associated factor (PCAF) and related GCN5 bromodomain-containing lysine acetyl transferases are members of subfamilyâ I of the bromodomain phylogenetic tree. Iterative cycles of rational inhibitor design and biophysical characterization led to the discovery of the triazolopthalazine-based L-45 (dubbed L-Moses) as the first potent, selective, and cell-active PCAF bromodomain (Brd) inhibitor. Synthesis from readily available (1R,2S)-(-)-norephedrine furnished L-45 in enantiopure form. L-45 was shown to disrupt PCAF-Brd histone H3.3 interaction in cells using a nanoBRET assay, and a co-crystal structure of L-45 with the homologous Brd PfGCN5 from Plasmodium falciparum rationalizes the high selectivity for PCAF and GCN5 bromodomains. Compound L-45 shows no observable cytotoxicity in peripheral blood mononuclear cells (PBMC), good cell-permeability, and metabolic stability in human and mouse liver microsomes, supporting its potential for inâ vivo use.
Asunto(s)
Compuestos Azo/farmacología , Descubrimiento de Drogas , Hidralazina/farmacología , Sondas Moleculares/farmacología , Factores de Transcripción p300-CBP/antagonistas & inhibidores , Compuestos Azo/síntesis química , Compuestos Azo/química , Relación Dosis-Respuesta a Droga , Hidralazina/síntesis química , Hidralazina/química , Sondas Moleculares/síntesis química , Sondas Moleculares/química , Estructura Molecular , Relación Estructura-ActividadRESUMEN
The bromodomain family of proteins are 'readers' of acetylated lysines of histones, a key mark in the epigenetic code of gene regulation. Without high quality chemical probes with which to study these proteins, their biological function, and potential use in therapeutics, remains unknown. Recently, a number of chemical ligands were reported for the previously unprobed bromodomain proteins BRD7 and BRD9. Herein the development and characterisation of probes against these proteins is detailed, including the preliminary biological activity of BRD7 and BRD9 assessed using these probes. Future studies utilising these chemically-diverse compounds in parallel will allow for a confident assessment of the role of BRD7/9, and give multiple entry points into any subsequent pharmaceutical programs.
Asunto(s)
Proteínas Cromosómicas no Histona/química , Dominios Proteicos , Factores de Transcripción/química , Animales , Proteínas Cromosómicas no Histona/metabolismo , Diseño de Fármacos , Humanos , Ligandos , Factores de Transcripción/metabolismoRESUMEN
Gastric cancer is one of the most common malignancies and a leading cause of cancer death worldwide. The prognosis of stomach cancer is generally poor as this cancer is not very sensitive to commonly used chemotherapies. Epigenetic modifications play a key role in gastric cancer and contribute to the development and progression of this malignancy. In order to explore new treatment options in this target area we have screened a library of epigenetic inhibitors against gastric cancer cell lines and identified inhibitors for the BET family of bromodomains as potent inhibitors of gastric cancer cell proliferations. Here we show that both the pan-BET inhibitor (+)-JQ1 as well as a newly developed specific isoxazole inhibitor, PNZ5, showed potent inhibition of gastric cancer cell growth. Intriguingly, we found differences in the antiproliferative response between gastric cancer cells tested derived from Brazilian patients as compared to those from Asian patients, the latter being largely resistant to BET inhibition. As BET inhibitors are entering clinical trials these findings provide the first starting point for future therapies targeting gastric cancer.
Asunto(s)
Azepinas/farmacología , Proliferación Celular/efectos de los fármacos , Isoxazoles/farmacología , Proteínas Nucleares/antagonistas & inhibidores , Factores de Transcripción/antagonistas & inhibidores , Triazoles/farmacología , Apoptosis/efectos de los fármacos , Apoptosis/genética , Pueblo Asiatico , Azepinas/química , Brasil , Proteínas de Ciclo Celular , Línea Celular Tumoral , Proliferación Celular/genética , Perfilación de la Expresión Génica , Células HEK293 , Humanos , Isoxazoles/química , Estructura Molecular , Proteínas Nucleares/genética , Proteínas Nucleares/metabolismo , Proteínas Proto-Oncogénicas c-myc/genética , Proteínas Proto-Oncogénicas c-myc/metabolismo , Esferoides Celulares/efectos de los fármacos , Esferoides Celulares/metabolismo , Neoplasias Gástricas/etnología , Neoplasias Gástricas/genética , Neoplasias Gástricas/metabolismo , Factores de Transcripción/genética , Factores de Transcripción/metabolismo , Triazoles/químicaRESUMEN
In the last five years, the development of inhibitors of bromodomains has emerged as an area of intensive worldwide research. Emerging evidence has implicated a number of non-BET bromodomains in the onset and progression of diseases such as cancer, HIV infection and inflammation. The development and use of small molecule chemical probes has been fundamental to pre-clinical evaluation of bromodomains as targets. Recent efforts are described highlighting the development of potent, selective and cell active non-BET bromodomain inhibitors and their therapeutic potential. Over half of typical bromodomains now have reported ligands, but those with atypical binding site residues remain resistant to chemical probe discovery efforts.
RESUMEN
The bromodomain-containing proteins BRD9 and BRD7 are part of the human SWI/SNF chromatin-remodeling complexes BAF and PBAF. To date, no selective inhibitor for BRD7/9 has been reported despite its potential value as a biological tool or as a lead for future therapeutics. The quinolone-fused lactam LP99 is now reported as the first potent and selective inhibitor of the BRD7 and BRD9 bromodomains. Development of LP99 from a fragment hit was expedited through balancing structure-based inhibitor design and biophysical characterization against tractable chemical synthesis: Complexity-building nitro-Mannich/lactamization cascade processes allowed for early structure-activity relationship studies whereas an enantioselective organocatalytic nitro-Mannich reaction enabled the synthesis of the lead scaffold in enantioenriched form and on scale. This epigenetic probe was shown to inhibit the association of BRD7 and BRD9 to acetylated histones inâ vitro and in cells. Moreover, LP99 was used to demonstrate that BRD7/9 plays a role in regulating pro-inflammatory cytokine secretion.
Asunto(s)
Proteínas Cromosómicas no Histona/antagonistas & inhibidores , Descubrimiento de Drogas , Lactamas/química , Lactamas/farmacología , Factores de Transcripción/antagonistas & inhibidores , Proteínas Cromosómicas no Histona/química , Proteínas Cromosómicas no Histona/metabolismo , Humanos , Modelos Moleculares , Factores de Transcripción/química , Factores de Transcripción/metabolismoRESUMEN
The bromodomain-containing proteins BRD9 and BRD7 are part of the human SWI/SNF chromatin-remodeling complexes BAF and PBAF. To date, no selective inhibitor for BRD7/9 has been reported despite its potential value as a biological tool or as a lead for future therapeutics. The quinolone-fused lactam LP99 is now reported as the first potent and selective inhibitor of the BRD7 and BRD9 bromodomains. Development of LP99 from a fragment hit was expedited through balancing structure-based inhibitor design and biophysical characterization against tractable chemical synthesis: Complexity-building nitro-Mannich/lactamization cascade processes allowed for early structure-activity relationship studies whereas an enantioselective organocatalytic nitro-Mannich reaction enabled the synthesis of the lead scaffold in enantioenriched form and on scale. This epigenetic probe was shown to inhibit the association of BRD7 and BRD9 to acetylated histones inâ vitro and in cells. Moreover, LP99 was used to demonstrate that BRD7/9 plays a role in regulating pro-inflammatory cytokine secretion.
RESUMEN
Malonganenone B (1) exhibits an unusual H-D exchange of a formyl proton when in deuteric-NMR solvents. Synthetic and kinetic investigations were made to probe the mechanism of this exchange, which appears to occur via an uncommon and transient amine-amide NHC intermediate.
Asunto(s)
Deuterio/química , Diterpenos/química , Hidrógeno/química , Imidazoles/química , Cinética , Metano/análogos & derivados , Metano/química , Estructura MolecularRESUMEN
Plasmodium falciparum heat shock protein 70 (PfHsp70-1) is thought to play an essential role in parasite survival and virulence in the human host, making it a potential antimalarial drug target. A malate dehydrogenase based aggregation suppression assay was adapted for the screening of small molecule modulators of Hsp70. A number of small molecules of natural (marine prenylated alkaloids and terrestrial plant naphthoquinones) and related synthetic origin were screened for their effects on the protein aggregation suppression activity of purified recombinant PfHsp70-1. Five compounds (malonganenone A-C, lapachol and bromo-ß-lapachona) were found to inhibit the chaperone activity of PfHsp70-1 in a concentration dependent manner, with lapachol preferentially inhibiting PfHsp70-1 compared to another control Hsp70. Using growth inhibition assays on P. falciparum infected erythrocytes, all of the compounds, except for malonganenone B, were found to inhibit parasite growth with IC(50) values in the low micromolar range. Overall, this study has identified two novel classes of small molecule inhibitors of PfHsp70-1, one representing a new class of antiplasmodial compounds (malonganenones). In addition to demonstrating the validity of PfHsp70-1 as a possible drug target, the compounds reported in this study will be potentially useful as molecular probes for fundamental studies on Hsp70 chaperone function.