RESUMO
Greater plant defence is predicted to evolve at lower latitudes in response to increased herbivore pressure. However, recent studies question the generality of this pattern. In this study, we tested for genetically based latitudinal clines in resistance to herbivores and underlying defence traits of Oenothera biennis. We grew plants from 137 populations from across the entire native range of O. biennis. Populations from lower latitudes showed greater resistance to multiple specialist and generalist herbivores. These patterns were associated with an increase in total phenolics at lower latitudes. A significant proportion of the phenolics were driven by the concentrations of two major ellagitannins, which exhibited opposing latitudinal clines. Our analyses suggest that these findings are unlikely to be explained by local adaptation of herbivore populations or genetic variation in phenology. Rather greater herbivory at high latitudes can be explained by latitudinal clines in the evolution of plant defences.
Assuntos
Variação Genética , Herbivoria , Oenothera biennis/fisiologia , Fenóis/metabolismo , Evolução Biológica , Canadá , Oenothera biennis/genética , Fenótipo , Estados UnidosRESUMO
The aberrant activity of histone deacetylases (HDACs) across a broad range of cancers and other disease indications has led to the development of small-molecule inhibitors that target one or more members of the HDAC protein family. Emerging HDAC inhibitors that show promise in drug discovery programs must be assessed across a range of in vitro assays to establish an inhibitor profile for potency and cellular selectivity towards target HDAC(s) as well as preliminary absorption, distribution, metabolism, and excretion (ADME) features. Here we provide an overview of methods to determine a subset of pivotal in vitro drug-like parameters for HDAC inhibitors (HDACi). We initially describe protocols for parallel artificial membrane permeability assays (PAMPA) to evaluate the passive permeability of small molecules across lipid membranes. Subsequently, we elaborate on cytotoxicity assays using CellTiter-Blue to determine HDACi-induced cell death in healthy/diseased cellular models. We next focus on assessing the target engagement of inhibitors with the appropriate HDAC isoforms in a cellular environment via Western blotting of acetylated HDAC substrates. Finally, we provide detailed guidelines on how to assess the metabolic stability of HDACi through whole blood stability assays. Collectively, these assays provide an overview of the permeability, selectivity, and stability of the HDAC inhibitor under development.
Assuntos
Inibidores de Histona Desacetilases , Histona Desacetilases , Inibidores de Histona Desacetilases/farmacologia , Inibidores de Histona Desacetilases/química , Histona Desacetilases/metabolismo , Isoformas de Proteínas/metabolismo , Membranas Artificiais , LipídeosRESUMO
Histone deacetylases (HDACs) have emerged as powerful epigenetic modifiers of histone/non-histone proteins via catalyzing the deacetylation of ε-N-acetyl lysines. The dysregulated activity of these Zn2+-dependent hydrolases has been broadly implicated in disease, notably cancer. Clinically, the recurring dose-limiting toxicities of first-generation HDACi sparked a paradigm shift toward safer isoform-specific molecules. With pervasive roles in aggressive diseases, there remains a need for novel approaches to target these enzymes. Herein, we report the discovery of YSR734, a first-in-class covalent HDACi, with a 2-aminobenzanilide Zn2+ chelate and a pentafluorobenzenesulfonamide electrophile. This class I selective proof of concept modified HDAC2Cys274 (catalytic domain), with nM potency against HDAC1-3, sub-µM activity in MV4-11 cells, and limited cytotoxicity in MRC-9 fibroblasts. In C2C12 myoblasts, YSR734 activated muscle-specific biomarkers myogenin/Cav3, causing potent differentiation into myotubes (applications in Duchenne Muscular Dystrophy). Current efforts are focused on improving in vivo ADME toward a preclinical covalent HDACi.
Assuntos
Leucemia Mieloide Aguda , Distrofia Muscular de Duchenne , Humanos , Inibidores de Histona Desacetilases/farmacologia , Inibidores de Histona Desacetilases/uso terapêutico , Distrofia Muscular de Duchenne/tratamento farmacológico , Isoformas de Proteínas/metabolismo , Histona Desacetilases/metabolismo , Leucemia Mieloide Aguda/tratamento farmacológicoRESUMO
NK/T-cell lymphoma (NKTCL) and γδ T-cell non-Hodgkin lymphomas (γδ T-NHL) are highly aggressive lymphomas that lack rationally designed therapies and rely on repurposed chemotherapeutics from other hematological cancers. Histone deacetylases (HDACs) have been targeted in a range of malignancies, including T-cell lymphomas. This study represents exploratory findings of HDAC6 inhibition in NKTCL and γδ T-NHL through a second-generation inhibitor NN-429. With nanomolar in vitro HDAC6 potency and high in vitro and in cellulo selectivity for HDAC6, NN-429 also exhibited long residence time and improved pharmacokinetic properties in contrast to older generation inhibitors. Following unique selective cytotoxicity towards γδ T-NHL and NKTCL, NN-429 demonstrated a synergistic relationship with the clinical agent etoposide and potential synergies with doxorubicin, cytarabine, and SNS-032 in these disease models, opening an avenue for combination treatment strategies.
RESUMO
Histone deacetylase 6 (HDAC6) has been targeted in clinical studies for anticancer effects due to its role in oncogenic transformation and metastasis. Through a second-generation structure-activity relationship (SAR) study, the design, and biological evaluation of the selective HDAC6 inhibitor NN-390 is reported. With nanomolar HDAC6 potency, >200-550-fold selectivity for HDAC6 in analogous HDAC isoform functional assays, potent intracellular target engagement, and robust cellular efficacy in cancer cell lines, NN-390 is the first HDAC6-selective inhibitor to show therapeutic potential in metastatic Group 3 medulloblastoma (MB), an aggressive pediatric brain tumor often associated with leptomeningeal metastases and therapy resistance. MB stem cells contribute to these patients' poor clinical outcomes. NN-390 selectively targets this cell population with a 44.3-fold therapeutic margin between patient-derived Group 3 MB cells in comparison to healthy neural stem cells. NN-390 demonstrated a 45-fold increased potency over HDAC6-selective clinical candidate citarinostat. In summary, HDAC6-selective molecules demonstrated in vitro therapeutic potential against Group 3 MB.
Assuntos
Antineoplásicos/farmacologia , Neoplasias Encefálicas/tratamento farmacológico , Desacetilase 6 de Histona/antagonistas & inibidores , Inibidores de Histona Desacetilases/síntese química , Inibidores de Histona Desacetilases/farmacologia , Meduloblastoma/tratamento farmacológico , Linhagem Celular Tumoral , Sobrevivência Celular/efeitos dos fármacos , Simulação por Computador , Descoberta de Drogas , Ensaios de Seleção de Medicamentos Antitumorais , Humanos , Modelos Moleculares , Simulação de Acoplamento Molecular , Células-Tronco Neoplásicas/efeitos dos fármacos , Relação Estrutura-AtividadeRESUMO
Histone deacetylase 6 (HDAC6) is involved in multiple regulatory processes, ranging from cellular stress to intracellular transport. Inhibition of aberrant HDAC6 activity in several cancers and neurological diseases has been shown to be efficacious in both preclinical and clinical studies. While selective HDAC6 targeting has been pursued as an alternative to pan-HDAC drugs, identifying truly selective molecular templates has not been trivial. Herein, we report a structure-activity relationship study yielding TO-317, which potently binds HDAC6 catalytic domain 2 (Ki = 0.7 nM) and inhibits the enzyme function (IC50 = 2 nM). TO-317 exhibits 158-fold selectivity for HDAC6 over other HDAC isozymes by binding the catalytic Zn2+ and, uniquely, making a never seen before direct hydrogen bond with the Zn2+ coordinating residue, His614. This novel structural motif targeting the second-sphere His614 interaction, observed in a 1.84 Å resolution crystal structure with drHDAC6 from zebrafish, can provide new pharmacophores for identifying enthalpically driven, high-affinity, HDAC6-selective inhibitors.
Assuntos
Desacetilase 6 de Histona/antagonistas & inibidores , Inibidores de Histona Desacetilases/farmacologia , Ácidos Hidroxâmicos/farmacologia , Sulfonamidas/farmacologia , Animais , Domínio Catalítico , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Desacetilase 6 de Histona/metabolismo , Inibidores de Histona Desacetilases/síntese química , Inibidores de Histona Desacetilases/metabolismo , Inibidores de Histona Desacetilases/farmacocinética , Humanos , Ácidos Hidroxâmicos/síntese química , Ácidos Hidroxâmicos/metabolismo , Ácidos Hidroxâmicos/farmacocinética , Masculino , Camundongos Endogâmicos BALB C , Simulação de Acoplamento Molecular , Estrutura Molecular , Ligação Proteica , Relação Estrutura-Atividade , Sulfonamidas/síntese química , Sulfonamidas/metabolismo , Sulfonamidas/farmacocinética , Peixe-Zebra , Proteínas de Peixe-Zebra/antagonistas & inibidores , Proteínas de Peixe-Zebra/metabolismoRESUMO
Epigenetic targeting has emerged as an efficacious therapy for hematological cancers. The rare and incurable T-cell prolymphocytic leukemia (T-PLL) is known for its aggressive clinical course. Current epigenetic agents such as histone deacetylase (HDAC) inhibitors are increasingly used for targeted therapy. Through a structure-activity relationship (SAR) study, we developed an HDAC6 inhibitor KT-531, which exhibited higher potency in T-PLL compared to other hematological cancers. KT-531 displayed strong HDAC6 inhibitory potency and selectivity, on-target biological activity, and a safe therapeutic window in nontransformed cell lines. In primary T-PLL patient cells, where HDAC6 was found to be overexpressed, KT-531 exhibited strong biological responses, and safety in healthy donor samples. Notably, combination studies in T-PLL patient samples demonstrated KT-531 synergizes with approved cancer drugs, bendamustine, idasanutlin, and venetoclax. Our work suggests HDAC inhibition in T-PLL could afford sufficient therapeutic windows to achieve durable remission either as stand-alone or in combination with targeted drugs.
Assuntos
Antineoplásicos/uso terapêutico , Inibidores de Histona Desacetilases/uso terapêutico , Ácidos Hidroxâmicos/uso terapêutico , Leucemia Prolinfocítica de Células T/tratamento farmacológico , Sulfonamidas/uso terapêutico , Animais , Antineoplásicos/síntese química , Antineoplásicos/farmacocinética , Apoptose/efeitos dos fármacos , Cloridrato de Bendamustina/farmacologia , Compostos Bicíclicos Heterocíclicos com Pontes/farmacologia , Linhagem Celular Tumoral , Sinergismo Farmacológico , Desacetilase 6 de Histona/metabolismo , Inibidores de Histona Desacetilases/síntese química , Inibidores de Histona Desacetilases/farmacocinética , Humanos , Ácidos Hidroxâmicos/síntese química , Ácidos Hidroxâmicos/farmacocinética , Masculino , Camundongos , Simulação de Acoplamento Molecular , Estrutura Molecular , Pirrolidinas/farmacologia , Relação Estrutura-Atividade , Sulfonamidas/síntese química , Sulfonamidas/farmacocinética , Sulfonamidas/farmacologia , para-Aminobenzoatos/farmacologiaRESUMO
Histone deacetylases (HDACs) are an attractive therapeutic target for a variety of human diseases. Currently, all four FDA-approved HDAC-targeting drugs are nonselective, pan-HDAC inhibitors, exhibiting adverse side effects at therapeutic doses. Although selective HDAC inhibition has been proposed to mitigate toxicity, the targeted catalytic domains are highly conserved. Herein, we describe a series of rationally designed, conformationally constrained, benzanilide foldamers which selectively bind the catalytic tunnel of HDAC8. The series includes benzanilides, MMH371, MMH409, and MMH410, which exhibit potent in vitro HDAC8 activity (IC50 = 66, 23, and 66 nM, respectively) and up to 410-fold selectivity for HDAC8 over the next targeted HDAC. Experimental and computational analyses of the benzanilide structure docked with human HDAC8 enzyme showed the adoption of a low-energy L-shaped conformer that favors HDAC8 selectivity. The conformationally constrained HDAC8 inhibitors present an alternative biological probe for further determining the clinical utility and safety of pharmacological knockdown of HDAC8 in diseased cells.
Assuntos
Anilidas/química , Anilidas/farmacologia , Inibidores de Histona Desacetilases/química , Inibidores de Histona Desacetilases/farmacologia , Proteínas Repressoras/antagonistas & inibidores , Domínio Catalítico/efeitos dos fármacos , Desenho de Fármacos , Histona Desacetilases/metabolismo , Humanos , Simulação de Acoplamento Molecular , Proteínas Repressoras/metabolismo , Relação Estrutura-AtividadeRESUMO
The HDAC inhibitor 4-tert-butyl-N-(4-(hydroxycarbamoyl)phenyl)benzamide (AES-350, 51) was identified as a promising preclinical candidate for the treatment of acute myeloid leukemia (AML), an aggressive malignancy with a meagre 24% 5-year survival rate. Through screening of low-molecular-weight analogues derived from the previously discovered novel HDAC inhibitor, AES-135, compound 51 demonstrated greater HDAC isoform selectivity, higher cytotoxicity in MV4-11 cells, an improved therapeutic window, and more efficient absorption through cellular and lipid membranes. Compound 51 also demonstrated improved oral bioavailability compared to SAHA in mouse models. A broad spectrum of experiments, including FACS, ELISA, and Western blotting, were performed to support our hypothesis that 51 dose-dependently triggers apoptosis in AML cells through HDAC inhibition.
RESUMO
Dysregulated Histone Deacetylase (HDAC) activity across multiple human pathologies have highlighted this family of epigenetic enzymes as critical druggable targets, amenable to small molecule intervention. While efficacious, current approaches using non-selective HDAC inhibitors (HDACi) have been shown to cause a range of undesirable clinical toxicities. To circumvent this, recent efforts have focused on the design of highly selective HDACi as a novel therapeutic strategy. Beyond roles in regulating transcription, the unique HDAC6 (with two catalytic domains) regulates the deacetylation of α-tubulin; promoting growth factor-controlled cell motility, cell division, and metastatic hallmarks. Recent studies have linked aberrant HDAC6 function in various hematological cancers including acute myeloid leukaemia and multiple myeloma. Herein, we report the discovery, in vitro characterization, and biological evaluation of PTG-0861 (JG-265), a novel HDAC6-selective inhibitor with strong isozyme-selectivity (â¼36× ) and low nanomolar potency (IC50 = 5.92 nM) against HDAC6. This selectivity profile was rationalized via in silico docking studies and also observed in cellulo through cellular target engagement. Moreover, PTG-0861 achieved relevant potency against several blood cancer cell lines (e.g. MV4-11, MM1S), whilst showing limited cytotoxicity against non-malignant cells (e.g. NHF, HUVEC) and CD-1 mice. In examining compound stability and cellular permeability, PTG-0861 revealed a promising in vitro pharmacokinetic (PK) profile. Altogether, in this study we identified a novel and potent HDAC6-selective inhibitor (â¼4× more selective than current clinical standards - citarinostat, ricolinostat), which achieves cellular target engagement, efficacy in hematological cancer cells with a promising safety profile and in vitro PK.