RESUMO
In this study, we have identified and optimized two lead structures from an in-house screening, with promising results against the parasitic flatworm Schistosoma mansoni and its target protease S. mansoni cathepsin B1 (SmCB1). Our correlation analysis highlighted the significance of physicochemical properties for the compounds' in vitro activities, resulting in a dual approach to optimize the lead structures, regarding both phenotypic effects in S. mansoni newly transformed schistosomula (NTS), adult worms, and SmCB1 inhibition. The optimized compounds from both approaches ("phenotypic" vs "SmCB1" approach) demonstrated improved efficacy against S. mansoni NTS and adult worms, with 2h from the "SmCB1" approach emerging as the most potent compound. 2h displayed nanomolar inhibition of SmCB1 (Ki = 0.050 µM) while maintaining selectivity toward human off-target cathepsins. Additionally, the greatly improved efficacy of compound 2h toward S. mansoni adults (86% dead worms at 10 µM, 68% at 1 µM, 35% at 0.1 µM) demonstrates its potential as a new therapeutic agent for schistosomiasis, underlined by its improved permeability.
Assuntos
Catepsina B , Schistosoma mansoni , Schistosoma mansoni/efeitos dos fármacos , Schistosoma mansoni/enzimologia , Schistosoma mansoni/genética , Animais , Catepsina B/antagonistas & inibidores , Catepsina B/metabolismo , Esquistossomose mansoni/tratamento farmacológico , Desenho de Fármacos , Humanos , Fenótipo , Relação Estrutura-Atividade , Anti-Helmínticos/farmacologia , Anti-Helmínticos/química , Proteínas de Helminto/antagonistas & inibidoresRESUMO
The NS2B/NS3 serine proteases of the Zika and Dengue flaviviruses are attractive targets for the development of antiviral drugs. We report the synthesis and evaluation of a new, proline-based compound class that displays allosteric inhibition of both proteases. The structural features relevant for protease binding and inhibition were determined to establish them as new lead compounds for flaviviral inhibitors. Based on our structure-activity relationship studies, the molecules were further optimized, leading to inhibitors with submicromolar IC50 values and improved lipophilic ligand efficiency. The allosteric binding site in the proteases was probed using mutagenesis and covalent modification of the obtained cysteine mutants with maleimides, followed by computational elucidation of the possible binding modes. In infected cells, antiviral activity against Dengue virus serotype 2 using prodrugs of the inhibitors was observed. In summary, a novel inhibitor scaffold targeting an allosteric site shared between flaviviral NS2B/NS3 proteases is presented whose efficacy is demonstrated in vitro and in cellulo.
Assuntos
Antivirais/farmacologia , Vírus da Dengue/efeitos dos fármacos , Dengue/tratamento farmacológico , Prolina/química , Inibidores de Proteases/farmacologia , Proteínas não Estruturais Virais/antagonistas & inibidores , Infecção por Zika virus/tratamento farmacológico , Zika virus/efeitos dos fármacos , Células A549 , Regulação Alostérica , Sítio Alostérico , Antivirais/química , Domínio Catalítico , Dengue/metabolismo , Dengue/virologia , Vírus da Dengue/enzimologia , Humanos , Simulação de Acoplamento Molecular , Peptídeo Hidrolases , Inibidores de Proteases/química , Ligação Proteica , Conformação Proteica , Serina Endopeptidases/química , Relação Estrutura-Atividade , Proteínas Virais/antagonistas & inibidores , Zika virus/enzimologia , Infecção por Zika virus/metabolismo , Infecção por Zika virus/virologiaRESUMO
Golgi α-mannosidase II (GMII) is a glycoside hydrolase playing a crucial role in the N-glycosylation pathway. In various tumour cell lines, the distribution of N-linked sugars on the cell surface is modified and correlates with the progression of tumour metastasis. GMII therefore is a possible molecular target for anticancer agents. Here, we describe the identification of a non-competitive GMII inhibitor using computer-aided drug design methods including identification of a possible allosteric binding site, pharmacophore search and virtual screening.
Assuntos
Desenho de Fármacos , Complexo de Golgi/enzimologia , alfa-Manosidase/ultraestrutura , Sítio Alostérico , Animais , Sítios de Ligação , Clonagem Molecular , Drosophila melanogaster/enzimologia , Simulação de Acoplamento Molecular , Estrutura Quaternária de Proteína , Proteínas RecombinantesRESUMO
In the present work a series of aziridine-2,3-dicarboxylate inhibitors of papain-like cysteine proteases was designed, synthesized and tested. The compounds displayed selectivity for the parasitic protozoon Leishmania mexicana cathepsin L-like cysteine protease LmCPB2.8. The computational methods of homology modelling and molecular docking predicted some significant differences in the S2 pocket of LmCPB2.8 and cruzain, a related enzyme from Trypanosoma cruzi. Due to the presence of Tyr209 in LmCPB2.8 rather than Glu208 in cruzain sterically demanding, lipophilic ester groups (inhibitor 7d, 9d, 12d and 14d) are predicted to occupy the S2 pocket of the Leishmania protease, but do not form favorable interactions in cruzain, which is in common with our experimental results. Further, inhibitor 18 bearing a free carboxylic acid attached to the aziridine moiety showed a time-dependent inhibition of LmCPB2.8 (Kiâ¯=â¯0.41⯵M; k2ndâ¯=â¯190,569â¯M-1â¯min-1). Docking results suggested a strong ionic interaction with the positively charged His163 of the active site. Biological and theoretical data confirm that the novel selective aziridine-based inhibitors are promising candidates for further optimization as LmCPB2.8 inhibitors.
Assuntos
Aziridinas/química , Aziridinas/farmacologia , Catepsina L/antagonistas & inibidores , Inibidores de Cisteína Proteinase/química , Inibidores de Cisteína Proteinase/farmacologia , Leishmania/enzimologia , Antiparasitários/química , Antiparasitários/farmacologia , Catepsina L/metabolismo , Descoberta de Drogas , Humanos , Leishmania/efeitos dos fármacos , Leishmania mexicana/efeitos dos fármacos , Leishmania mexicana/enzimologia , Leishmaniose/tratamento farmacológico , Leishmaniose/parasitologia , Leishmaniose Cutânea/tratamento farmacológico , Leishmaniose Cutânea/parasitologia , Simulação de Acoplamento MolecularRESUMO
Cysteine proteinases (cathepsins) from Leishmania spp. are promising molecular targets against leishmaniasis. Leishmania mexicana cathepsin L is essential in the parasite life cycle and a pivotal in virulence factor in mammals. Natural products that have been shown to display antileishmanial activity were screened as part of our ongoing efforts to design inhibitors against the L. mexicana cathepsin L-like rCPB2.8. Among them, agathisflavone (1), tetrahydrorobustaflavone (2), 3-oxo-urs-12-en-28-oic acid (3), and quercetin (4) showed significant inhibitory activity on rCPB2.8 with IC50 values ranging from 0.43 to 18.03 µM. The mechanisms of inhibition for compounds 1-3, which showed Ki values in the low micromolar range (Ki = 0.14-1.26 µM), were determined. The biflavone 1 and the triterpene 3 are partially noncompetitive inhibitors, whereas biflavanone 2 is an uncompetitive inhibitor. The mechanism of action established for these leishmanicidal natural products provides a new outlook in the search for drugs against Leishmania.
Assuntos
Produtos Biológicos/farmacologia , Catepsina L/antagonistas & inibidores , Leishmania mexicana/enzimologia , Biflavonoides/farmacologia , Catepsina B/antagonistas & inibidores , Catepsina B/genética , Catepsina L/genética , Humanos , Concentração Inibidora 50 , Cinética , Leishmania mexicana/genética , Quercetina/farmacologia , Proteínas Recombinantes/efeitos dos fármacos , Proteínas Recombinantes/genéticaRESUMO
NS2B-NS3 is a serine protease of the Dengue virus considered a key target in the search for new antiviral drugs. In this study flavonoids were found to be inhibitors of NS2B-NS3 proteases of the Dengue virus serotypes 2 and 3 with IC50 values ranging from 15 to 44 µM. Agathisflavone (1) and myricetin (4) turned out to be noncompetitive inhibitors of dengue virus serotype 2 NS2B-NS3 protease with Ki values of 11 and 4.7 µM, respectively. Docking studies propose a binding mode of the flavonoids in a specific allosteric binding site of the enzyme. Analysis of biomolecular interactions of quercetin (5) with NT647-NHS-labeled Dengue virus serotype 3 NS2B-NS3 protease by microscale thermophoresis experiments, yielded a dissociation constant KD of 20 µM. Our results help to understand the mechanism of inhibition of the Dengue virus serine protease by flavonoids, which is essential for the development of improved inhibitors.
Assuntos
Vírus da Dengue/enzimologia , Flavonoides/farmacologia , Serina Endopeptidases/química , Inibidores de Serina Proteinase/química , Inibidores de Serina Proteinase/farmacologia , Antivirais/química , Antivirais/farmacologia , Vírus da Dengue/efeitos dos fármacos , Flavonoides/química , Cinética , Modelos Moleculares , Simulação de Acoplamento Molecular , Serina Endopeptidases/metabolismo , Relação Estrutura-AtividadeRESUMO
The aim was to study the COX-1 inhibiting efficacy in context with hydroxyl radical scavenging properties of compounds bearing a carboxylic acid and ester function, respectively. In general, the acids are more potent radical scavengers than the corresponding esters but there is no clear correlation with their COX-1 inhibiting potencies. A feasible scavenging mechanism of carboxylic acids is discussed.
Assuntos
Ciclo-Oxigenase 1/efeitos dos fármacos , Inibidores de Ciclo-Oxigenase/farmacologia , Sequestradores de Radicais Livres/farmacologia , Radical Hidroxila/metabolismo , Animais , Bovinos , Relação Estrutura-AtividadeAssuntos
Anticonvulsivantes/química , Anticonvulsivantes/farmacologia , Animais , Ácido Glutâmico/fisiologia , Humanos , Receptores de AMPA/efeitos dos fármacos , Receptores de GABA/efeitos dos fármacos , Receptores de N-Metil-D-Aspartato/efeitos dos fármacos , Receptores de Neurotransmissores/efeitos dos fármacos , Relação Estrutura-AtividadeAssuntos
Anticonvulsivantes/uso terapêutico , Epilepsia/tratamento farmacológico , Animais , Benzodiazepinas/uso terapêutico , Carbamazepina/análogos & derivados , Carbamazepina/uso terapêutico , Felbamato , Humanos , Levetiracetam , Fenilcarbamatos/uso terapêutico , Piracetam/administração & dosagem , Piracetam/análogos & derivados , Piracetam/uso terapêutico , Propilenoglicóis/uso terapêutico , Ácido Valproico/análogos & derivados , Ácido Valproico/uso terapêuticoRESUMO
Cyclooxygenase-2 selective inhibitors have long been regarded as potent anti-inflammatory drugs for the treatment of arthritis, osteoarthritis and dysmenorrhea. The reports of cardiovascular risk and the subsequent withdrawal of rofecoxib, and recently valdecoxib, has called the therapeutic potential of coxibs into question. Currently, according to the latest decisions of the US Food and Drug Administration and European Medicines Agency, the approval of valdecoxib has been refused for 1 year due to an increased rate of cardiovascular risks and serious skin reactions. There are restrictions concerning the use of all other coxibs. The short-time use of coxibs, however, in anti-inflammatory treatment and in perioperative settings may become important in the future. Exact insights into the processes of pain modulation explain the benefit of coxibs in reducing peripheral and central nociception, and their use in pre-emptive and multimodal pain management. In the future, coxibs could be established into a personalized therapy in patients with a low cardiovascular risk, but with increased risk of gastrointestinal complications.
RESUMO
Treatment of an equimolar mixture of stilbene 7 and cinnamyl alcohol 8 with silver carbonate in acetone-benzene afforded a ca. 2:1:2:1 mixture of the stilbenolignan (+/-)-aiphanol (1) and congeners 2-4 each of which show significant anti-angiogenic and COX-2 inhibitory properties.
Assuntos
Estilbenos/química , Estilbenos/síntese química , Estilbenos/farmacologia , Inibidores da Angiogênese/síntese química , Inibidores da Angiogênese/farmacologia , Animais , Aorta/efeitos dos fármacos , Ciclo-Oxigenase 1 , Ciclo-Oxigenase 2 , Inibidores de Ciclo-Oxigenase 2 , Inibidores de Ciclo-Oxigenase/síntese química , Inibidores de Ciclo-Oxigenase/farmacologia , Relação Dose-Resposta a Droga , Concentração Inibidora 50 , Isoenzimas/antagonistas & inibidores , Espectroscopia de Ressonância Magnética , Proteínas de Membrana , Prostaglandina-Endoperóxido Sintases , Ratos , EstereoisomerismoRESUMO
The discovery of the two isoenzymes of cyclooxygenase COX-1 and COX-2 and their separate functions, localization and regulation, has initiated the search for new and more selective inhibitors of prostaglandin biosynthesis. Selective COX-2 inhibitors were developed in order to improve an anti-inflammatory and analgesic specificity and potency. The role of inducible COX-2 at the peripheral site of inflammation is well known. The discovery of COX-2 in the spinal cord suggests that it is responsible for spinal prostaglandin release in nociceptive processes following a peripheral inflammatory stimulus. In the future, selective COX-2 inhibitors such as celecoxib (GD Searle & Co), rofecoxib (Merck & Co Inc) and the recently developed etoricoxib (Merck & Co Inc) may play an important role in the treatment of a wider range of pain conditions in addition to their present use as anti-inflammatory and analgesic drugs.