RESUMEN
Histone deacetylases are considered promising epigenetic targets for chemical protein degradation due to their diverse roles in physiological cellular functions and in the diseased state. Proteolysis-targeting chimeras (PROTACs) are bifunctional molecules that hijack the cell's ubiquitin-proteasome system (UPS). One of the promising targets for this approach is histone deacetylase 6 (HDAC6), which is highly expressed in several types of cancers and is linked to the aggressiveness of tumors. In the present work, we describe the synthesis of HDAC6 targeting PROTACs based on previously synthesized benzohydroxamates selectively inhibiting HDAC6 and how to assess their activities in different biochemical in vitro assays and in cellular assays. HDAC inhibition was determined using fluorometric assays, while the degradation ability of the PROTACs was assessed using western blot analysis.
Asunto(s)
Neoplasias , Complejo de la Endopetidasa Proteasomal , Humanos , Histona Desacetilasa 6/metabolismo , Proteolisis , Complejo de la Endopetidasa Proteasomal/metabolismo , Quimera/metabolismo , Ubiquitina/metabolismo , Histona Desacetilasas/metabolismo , Ubiquitina-Proteína Ligasas/metabolismoRESUMEN
In addition to involvement in epigenetic gene regulation, histone deacetylases (HDACs) regulate multiple cellular processes through mediating the activity of non-histone protein substrates. The knockdown of HDAC8 isozyme is associated with the inhibition of cell proliferation and apoptosis enhancement in several cancer cell lines. As shown in several studies, HDAC8 can be considered a potential target in the treatment of cancer forms such as childhood neuroblastoma. The present work describes the development of proteolysis targeting chimeras (PROTACs) of HDAC8 based on substituted benzhydroxamic acids previously reported as potent and selective HDAC8 inhibitors. Within this study, we investigated the HDAC8-degrading profiles of the synthesized PROTACs and their effect on the proliferation of neuroblastoma cells. The combination of in vitro screening and cellular testing demonstrated selective HDAC8 PROTACs that show anti-neuroblastoma activity in cells.
Asunto(s)
Inhibidores de Histona Desacetilasas , Histona Desacetilasas , Neuroblastoma , Humanos , Línea Celular Tumoral/metabolismo , Inhibidores de Histona Desacetilasas/química , Inhibidores de Histona Desacetilasas/farmacología , Histona Desacetilasas/química , Histona Desacetilasas/metabolismo , Neuroblastoma/metabolismo , Proteolisis , Proteínas Represoras/metabolismoRESUMEN
Histone deacetylases (HDACs) are important epigenetic regulators involved in many diseases, especially cancer. Five HDAC inhibitors have been approved for anticancer therapy and many are in clinical trials. Among the 11 zinc-dependent HDACs, HDAC10 has received relatively little attention by drug discovery campaigns, despite its involvement, e. g., in the pathogenesis of neuroblastoma. This is due in part to a lack of robust enzymatic conversion assays. In contrast to the protein lysine deacetylase and deacylase activity of most other HDAC subtypes, it has recently been shown that HDAC10 has strong preferences for deacetylation of oligoamine substrates like acetyl-putrescine or -spermidine. Hence, it is also termed a polyamine deacetylase (PDAC). Here, we present the first fluorescent enzymatic conversion assay for HDAC10 using an aminocoumarin-labelled acetyl-spermidine derivative to measure its PDAC activity, which is suitable for high-throughput screening. Using this assay, we identified potent inhibitors of HDAC10-mediated spermidine deacetylation inâ vitro. Based on the oligoamine preference of HDAC10, we also designed inhibitors with a basic moiety in appropriate distance to the zinc binding hydroxamate that showed potent inhibition of HDAC10 with high selectivity, and we solved a HDAC10-inhibitor structure using X-ray crystallography. We could demonstrate selective cellular target engagement for HDAC10 but a lysosomal phenotype in neuroblastoma cells that was previously associated with HDAC10 inhibition was not observed. Thus, we have developed new chemical probes for HDAC10 that allow further clarification of the biological role of this enzyme.
Asunto(s)
Neuroblastoma , Espermidina , Inhibidores de Histona Desacetilasas/química , Inhibidores de Histona Desacetilasas/farmacología , Histona Desacetilasas/metabolismo , Humanos , Neuroblastoma/patología , Poliaminas/química , Espermidina/química , Espermidina/metabolismo , ZincRESUMEN
The search of new therapeutic tools for the treatment of cancer is being a challenge for medicinal chemists. Due to their role in different pathological conditions, histone deacetylase (HDAC) enzymes are considered valuable therapeutic targets. HDAC6 is a well-investigated HDAC-class IIb enzyme mainly characterized by a cytoplasmic localization; HDAC8 is an epigenetic eraser, unique HDAC-class I member that displays some aminoacidic similarity to HDAC6. New polypharmacological agents for cancer treatment, based on a dual hHDAC6/hHDAC8 inhibition profile were developed. The dual inhibitor design investigated the diphenyl-azetidin-2-one scaffold, typified in three different structural families, that, combined to a slender benzyl linker (6c, 6i, and 6j), displays nanomolar inhibition potency against hHDAC6 and hHDAC8 isoforms. Notably, their selective action was also corroborated by measuring their low inhibitory potency towards hHDAC1 and hHDAC10. Selectivity of these compounds was further demonstrated in human cell-based western blots experiments, by testing the acetylation of the non-histone substrates alpha-tubulin and SMC3. Furthermore, the compounds reduced the proliferation of colorectal HCT116 and leukemia U937 cells, after 48 h of treatment. The toxicity of the compounds was evaluated in rat perfused heart and in zebrafish embryos. In this latter model we also validated the efficacy of the dual hHDAC6/hHDAC8 inhibitors against their common target acetylated-alpha tubulin. Finally, the metabolic stability was verified in rat, mouse, and human liver microsomes.
Asunto(s)
Inhibidores de Histona Desacetilasas , Ácidos Hidroxámicos , Animales , Supervivencia Celular , Histona Desacetilasa 6 , Inhibidores de Histona Desacetilasas/química , Inhibidores de Histona Desacetilasas/farmacología , Histona Desacetilasas/metabolismo , Humanos , Ácidos Hidroxámicos/química , Ratones , Ratas , Proteínas Represoras , Tubulina (Proteína)/metabolismo , Pez Cebra/metabolismoRESUMEN
Histone deacetylases (HDACs) are a family of 18 epigenetic modifiers that fall into 4 classes. Histone deacetylase inhibitors (HDACi) are valid tools to assess HDAC functions. HDAC6 and HDAC10 belong to the class IIb subgroup of the HDAC family. The targets and biological functions of HDAC10 are ill-defined. This lack of knowledge is due to a lack of specific and potent HDAC10 inhibitors with cellular activity. Here, we have synthesized and characterized piperidine-4-acrylhydroxamates as potent and highly selective inhibitors of HDAC10. This was achieved by targeting the acidic gatekeeper residue Glu274 of HDAC10 with a basic piperidine moiety that mimics the interaction of the polyamine substrate of HDAC10. We have confirmed the binding modes of selected inhibitors using X-ray crystallography. Promising candidates were selected based on their specificity by in vitro profiling using recombinant HDACs. The most promising HDAC10 inhibitors 10c and 13b were tested for specificity in acute myeloid leukemia (AML) cells with the FLT3-ITD oncogene. By immunoblot experiments we assessed the hyperacetylation of histones and tubulin-α, which are class I and HDAC6 substrates, respectively. As validated test for HDAC10 inhibition we used flow cytometry assessing autolysosome formation in neuroblastoma and AML cells. We demonstrate that 10c and 13b inhibit HDAC10 with high specificity over HDAC6 and with no significant impact on class I HDACs. The accumulation of autolysosomes is not a consequence of apoptosis and 10c and 13b are not toxic for normal human kidney cells. These data show that 10c and 13b are nanomolar inhibitors of HDAC10 with high specificity. Thus, our new HDAC10 inhibitors are tools to identify the downstream targets and functions of HDAC10 in cells.
Asunto(s)
Inhibidores de Histona Desacetilasas , Leucemia Mieloide Aguda , Apoptosis , Autofagia , Histona Desacetilasa 1 , Histona Desacetilasa 6/metabolismo , Inhibidores de Histona Desacetilasas/química , Inhibidores de Histona Desacetilasas/farmacología , Histona Desacetilasas/metabolismo , HumanosRESUMEN
Writing and erasing of posttranslational modifications are crucial to phenotypic plasticity and antigenic variation of eukaryotic pathogens. Targeting pathogens' modification machineries, thus, represents a valid approach to fighting parasitic diseases. However, identification of parasitic targets and the development of selective anti-parasitic drugs still represent major bottlenecks. Here, we show that the zinc-dependent histone deacetylases (HDACs) of the protozoan parasite Trypanosoma cruzi are key regulators that have significantly diverged from their human counterparts. Depletion of T. cruzi class I HDACs tcDAC1 and tcDAC2 compromises cell-cycle progression and division, leading to cell death. Notably, tcDAC2 displays a deacetylase activity essential to the parasite and shows major structural differences with human HDACs. Specifically, tcDAC2 harbors a modular active site with a unique subpocket targeted by inhibitors showing substantial anti-parasitic effects in cellulo and in vivo. Thus, the targeting of the many atypical HDACs in pathogens can enable anti-parasitic selective chemical impairment.
Asunto(s)
Inhibidores de Histona Desacetilasas/farmacología , Histona Desacetilasas/genética , Histona Desacetilasas/metabolismo , Trypanosoma cruzi/enzimología , Trypanosoma cruzi/genética , Trypanosoma cruzi/metabolismo , Animales , Dominio Catalítico , Ciclo Celular , División Celular/efectos de los fármacos , Línea Celular , Proliferación Celular/efectos de los fármacos , Enfermedad de Chagas/tratamiento farmacológico , Enfermedad de Chagas/parasitología , Chlorocebus aethiops , ADN Protozoario , Femenino , Prueba de Complementación Genética , Inhibidores de Histona Desacetilasas/química , Histona Desacetilasas/química , Interacciones Huésped-Parásitos , Humanos , Masculino , Ratones , Ratones Endogámicos BALB C , Modelos Moleculares , Filogenia , Conformación Proteica , Procesamiento Proteico-Postraduccional , Proteínas Protozoarias/química , Proteínas Protozoarias/metabolismo , Eliminación de Secuencia , Trypanosoma cruzi/efectos de los fármacos , Células VeroRESUMEN
Idiopathic pulmonary fibrosis (IPF) is an interstitial lung disease characterized by a progressive-fibrosing phenotype. IPF has been associated with aberrant HDAC activities confirmed by our immunohistochemistry studies on HDAC6 overexpression in IPF lung tissues. We herein developed a series of novel hHDAC6 inhibitors, having low inhibitory potency over hHDAC1 and hHDAC8, as potential pharmacological tools for IPF treatment. Their inhibitory potency was combined with low in vitro and in vivo toxicity. Structural analysis of 6h and structure-activity relationship studies contributed to the optimization of the binding mode of the new molecules. The best-performing analogues were tested for their efficacy in inhibiting fibrotic sphere formation and cell viability, proving their capability in reverting the IPF phenotype. The efficacy of analogue 6h was also determined in a validated human lung model of TGF-ß1-dependent fibrogenesis. The results highlighted in this manuscript may pave the way for the identification of first-in-class molecules for the treatment of IPF.
Asunto(s)
Diseño de Fármacos , Histona Desacetilasa 6/antagonistas & inhibidores , Inhibidores de Histona Desacetilasas/farmacología , Fibrosis Pulmonar Idiopática/tratamiento farmacológico , Relación Dosis-Respuesta a Droga , Histona Desacetilasa 6/metabolismo , Inhibidores de Histona Desacetilasas/síntesis química , Inhibidores de Histona Desacetilasas/química , Humanos , Fibrosis Pulmonar Idiopática/metabolismo , Fibrosis Pulmonar Idiopática/patología , Modelos Moleculares , Estructura Molecular , Relación Estructura-ActividadRESUMEN
In this work we describe the synthesis of potent and selective quinolone-based histone deacetylase 6 (HDAC6) inhibitors. The quinolone moiety has been exploited as an innovative bioactive cap-group for HDAC6 inhibition; its synthesis was achieved by applying a multicomponent reaction. The optimization of potency and selectivity of these products was performed by employing computational studies which led to the discovery of the diethylaminomethyl derivatives 7g and 7k as the most promising hit molecules. These compounds were investigated in cellular studies to evaluate their anticancer effect against colon (HCT-116) and histiocytic lymphoma (U9347) cancer cells, showing good to excellent potency, leading to tumor cell death by apoptosis induction. The small molecules 7a, 7g and 7k were able to strongly inhibit the cytoplasmic and slightly the nuclear HDAC enzymes, increasing the acetylation of tubulin and of the lysine 9 and 14 of histone 3, respectively. Compound 7g was also able to increase Hsp90 acetylation levels in HCT-116 cells, thus further supporting its HDAC6 inhibitory profile. Cytotoxicity and mutagenicity assays of these molecules showed a safe profile; moreover, the HPLC analysis of compound 7k revealed good solubility and stability profile.
Asunto(s)
Histona Desacetilasa 6/antagonistas & inhibidores , Inhibidores de Histona Desacetilasas/farmacología , Quinolonas/farmacología , Animales , Línea Celular , Supervivencia Celular/efectos de los fármacos , Relación Dosis-Respuesta a Droga , Histona Desacetilasa 6/metabolismo , Inhibidores de Histona Desacetilasas/síntesis química , Inhibidores de Histona Desacetilasas/química , Humanos , Ratones , Modelos Moleculares , Estructura Molecular , Quinolonas/síntesis química , Quinolonas/química , Proteínas Recombinantes/metabolismo , Relación Estructura-ActividadRESUMEN
Histone deacetylase inhibitors (HDACi) have emerged as promising therapeutics for the treatment of neurodegeneration, cancer, and rare disorders. Herein, we report the development of a series of spiroindoline-based HDAC6 isoform-selective inhibitors based on the X-ray crystal studies of the hit 6a. We identified compound 6j as the most potent and selective hHDAC6 inhibitor of the series. Biological investigation of compounds 6b, 6h, and 6j demonstrated their antiproliferative activity against several cancer cell lines. Western blotting studies indicated that they were able to increase tubulin acetylation, without significant variation in histone acetylation state, and induced PARP cleavage indicating their apoptotic potential at the molecular level. 6j induced HDAC6-dependent pSTAT3 inhibition.
RESUMEN
New Thailandepsinâ B pseudo-natural products have been prepared. Our synthetic strategy offers the possibility to introduce varying warheads via late stage modification. Additionally, it gives access to the asymmetric branched allylic ester moiety of the natural product in a highly diastereoselective manner applying rhodium-catalyzed hydrooxycarbonylation. The newly developed pseudo-natural products are extremely potent and selective HDAC inhibitors. The non-proteinogenic amino acid d-norleucine was obtained enantioselectively by a recently developed method of rhodium-catalyzed hydroamination.
RESUMEN
Histone modifying proteins, specifically histone deacetylases (HDACs) and bromodomains, have emerged as novel promising targets for anticancer therapy. In the current work, based on available crystal structures and docking studies, we designed dual inhibitors of both HDAC6/8 and the bromodomain and PHD finger containing protein 1 (BRPF1). Biochemical and biophysical tests showed that compounds 23a,b and 37 are nanomolar inhibitors of both target proteins. Detailed structure-activity relationships were deduced for the synthesized inhibitors which were supported by extensive docking and molecular dynamics studies. Cellular testing in acute myeloid leukemia (AML) cells showed only a weak effect, most probably because of the poor permeability of the inhibitors. We also aimed to analyse the target engagement and the cellular activity of the novel inhibitors by determining the protein acetylation levels in cells by western blotting (tubulin vs histone acetylation), and by assessing their effects on various cancer cell lines.
Asunto(s)
Proteínas Adaptadoras Transductoras de Señales/antagonistas & inhibidores , Antineoplásicos/síntesis química , Proteínas de Unión al ADN/antagonistas & inhibidores , Diseño de Fármacos , Histona Desacetilasa 6/antagonistas & inhibidores , Proteínas Represoras/antagonistas & inhibidores , Acetilación/efectos de los fármacos , Antineoplásicos/farmacología , Línea Celular Tumoral , Inhibidores de Histona Desacetilasas/síntesis química , Inhibidores de Histona Desacetilasas/farmacología , Histona Desacetilasas , Humanos , Leucemia Mieloide Aguda/metabolismo , Leucemia Mieloide Aguda/patología , Simulación del Acoplamiento Molecular , Simulación de Dinámica Molecular , Relación Estructura-ActividadRESUMEN
Schistosomiasis (also known as bilharzia) is a neglected tropical disease caused by platyhelminths of the genus Schistosoma. The disease is endemic in tropical and subtropical areas of the world where water is infested by the intermediate parasite host, the snail. More than 800 million people live in endemic areas and more than 200 million are infected and require treatment. Praziquantel (PZQ) is the drug of choice for schistosomiasis treatment and transmission control being safe and very effective against adult worms of all the clinically relevant Schistosoma species. Unfortunately, it is ineffective on immature, juvenile worms; therefore, it does not prevent reinfection. Moreover, the risk of development and spread of drug resistance because of the widespread use of a single drug in such a large population represents a serious threat. Therefore, research aimed at identifying novel drugs to be used alone or in combination with PZQ are needed. Schistosoma mansoni histone deacetylase 8 (SmHDAC8) is a class I zinc-dependent HDAC, which is abundantly expressed in all stages of its life cycle, thus representing an interesting target for drug discovery. Through virtual screening and phenotypical characterization of selected hits, we discovered two main chemical classes of compounds characterized by the presence of a hydroxamate-based metal binding group coupled to a spiroindoline or a tricyclic thieno[3,2-b]indole core as capping groups. Some of the compounds of both classes were deeply investigated and showed to impair viability of larval, juvenile, and adult schistosomes, to impact egg production in vitro and/or to induce morphological alterations of the adult schistosome reproductive systems. Noteworthy, all of them inhibit the recombinant form of SmHDAC8 enzyme in vitro. Overall, we identified very interesting scaffolds, paving the way to the development of effective antischistosomal agents.
Asunto(s)
Antihelmínticos/farmacología , Descubrimiento de Drogas/métodos , Inhibidores de Histona Desacetilasas/farmacología , Schistosoma mansoni/efectos de los fármacos , Animales , Cristalografía por Rayos X , Femenino , Ensayos Analíticos de Alto Rendimiento , Inhibidores de Histona Desacetilasas/aislamiento & purificación , Masculino , Ratones , Simulación del Acoplamiento Molecular , Fenotipo , Schistosoma mansoni/enzimología , Relación Estructura-ActividadRESUMEN
The phenothiazine system was identified as a favorable cap group for potent and selective histone deacetylase 6 (HDAC6) inhibitors. Here, we report the preparation and systematic variation of phenothiazines and their analogues containing a benzhydroxamic acid moiety as the zinc-binding group. We evaluated their ability to selectively inhibit HDAC6 by a recombinant HDAC enzyme assay, by determining the protein acetylation levels in cells by western blotting (tubulin vs histone acetylation), and by assessing their effects on various cancer cell lines. Structure-activity relationship studies revealed that incorporation of a nitrogen atom into the phenothiazine framework results in increased potency and selectivity for HDAC6 (more than 500-fold selectivity relative to the inhibition of HDAC1, HDAC4, and HDAC8), as rationalized by molecular modeling and docking studies. The binding mode was confirmed by co-crystallization of the potent azaphenothiazine inhibitor with catalytic domain 2 from Danio rerio HDAC6.
Asunto(s)
Histona Desacetilasa 6/antagonistas & inhibidores , Inhibidores de Histona Desacetilasas/síntesis química , Inhibidores de Histona Desacetilasas/farmacología , Ácidos Hidroxámicos/química , Fenotiazinas/química , Acetilación , Animales , Dominio Catalítico , Células Cultivadas , Cristalografía por Rayos X , Células HL-60 , Histona Desacetilasa 6/metabolismo , Inhibidores de Histona Desacetilasas/química , Humanos , Técnicas In Vitro , Microsomas Hepáticos/efectos de los fármacos , Microsomas Hepáticos/enzimología , Microsomas Hepáticos/metabolismo , Simulación del Acoplamiento Molecular , Estructura Molecular , Relación Estructura-Actividad , Pez CebraRESUMEN
This paper describes the rational development of a series of novel spiroindoline derivatives endowed with selective inhibitory activity on the HDAC6 isoform. A convenient multicomponent one-pot protocol was applied for the assembly of the desired N1-substituted spiroindoline core which allowed a straightforward analoging. Computational studies and in vitro determination of inhibitory potency for the developed compounds against HDAC6 and HDAC1 isoforms were flanked by cell-based studies on histone H3 and α-tubulin acetylation. The effects on cancer cell cycle and apoptosis of the best performing derivatives were assessed on cancer cell lines highlighting a promising antitumor potential. In view of cell-based data and calculated drug-like properties, the selective HDAC6 inhibitor 5b, with a spiroindoline-based hydroxamate bearing a tert-butyl carbamate functionality, was selected to be further investigated for its potential in inhibiting tumor cells migration. It was able to potently inhibit cell migration in SH-SY5Y neuroblastoma cells and did not display toxicity in NIH3T3 mouse fibroblasts. Taken together, these data foster further investigation and optimization for this class of compounds as novel anticancer agents.
Asunto(s)
Antineoplásicos/farmacología , Histona Desacetilasa 1/antagonistas & inhibidores , Histona Desacetilasa 6/antagonistas & inhibidores , Inhibidores de Histona Desacetilasas/farmacología , Antineoplásicos/síntesis química , Antineoplásicos/química , Apoptosis/efectos de los fármacos , Ciclo Celular/efectos de los fármacos , Línea Celular Tumoral , Movimiento Celular/efectos de los fármacos , Proliferación Celular/efectos de los fármacos , Relación Dosis-Respuesta a Droga , Ensayos de Selección de Medicamentos Antitumorales , Histona Desacetilasa 1/metabolismo , Histona Desacetilasa 6/metabolismo , Inhibidores de Histona Desacetilasas/síntesis química , Inhibidores de Histona Desacetilasas/química , Humanos , Modelos Moleculares , Estructura Molecular , Relación Estructura-ActividadRESUMEN
Here we report the development of a proteolysis targeting chimera (PROTAC) based on the combination of the unique features of the sirtuin rearranging ligands (SirReals) as highly potent and isotype-selective Sirt2 inhibitors with thalidomide, a bona fide cereblon ligand. For the first time, we report the formation of a PROTAC by Cu(I)-catalyzed cycloaddition of a thalidomide-derived azide to an alkynylated inhibitor. This thalidomide-derived azide as well as the highly versatile linking strategy can be readily adapted to alkynylated ligands of other targets. In HeLa cells, our SirReal-based PROTAC induced isotype-selective Sirt2 degradation that results in the hyperacetylation of the microtubule network coupled with enhanced process elongation. Thus, our SirReal-based PROTAC is the first example of a probe that is able to chemically induce the degradation of an epigenetic eraser protein.
Asunto(s)
Proteolisis/efectos de los fármacos , Sirtuina 2/metabolismo , Talidomida/química , Acetilación , Proteínas Adaptadoras Transductoras de Señales , Técnicas de Química Sintética , Reacción de Cicloadición , Diseño de Fármacos , Células HeLa , Humanos , Ligandos , Modelos Moleculares , Simulación del Acoplamiento Molecular , Péptido Hidrolasas/química , Sirtuina 2/antagonistas & inhibidores , Sirtuina 2/química , Ubiquitina-Proteína LigasasRESUMEN
Histone deacetylases (HDACs) are important modulators of epigenetic gene regulation and additionally control the activity of non-histone protein substrates. While for HDACs 1-3 and 6 many potent selective inhibitors have been obtained, for other subtypes much less is known on selective inhibitors and the consequences of their inhibition. The present report describes the development of substituted benzhydroxamic acids as potent and selective HDAC8 inhibitors. Docking studies using available crystal structures have been used for structure-based optimization of this series of compounds. Within this study, we have investigated the role of HDAC8 in the proliferation of cancer cells and optimized hits for potency and selectivity, both in vitro and in cell culture. The combination of structure-based design, synthesis, and in vitro screening to cellular testing resulted in potent and selective HDAC8 inhibitors that showed anti-neuroblastoma activity in cellular testing.