RESUMO
We present a robust protocol based on iterations of free energy perturbation (FEP) calculations, chemical synthesis, biophysical mapping and X-ray crystallography to reveal the binding mode of an antagonist series to the A2A adenosine receptor (AR). Eight A2A AR binding site mutations from biophysical mapping experiments were initially analyzed with sidechain FEP simulations, performed on alternate binding modes. The results distinctively supported one binding mode, which was subsequently used to design new chromone derivatives. Their affinities for the A2A AR were experimentally determined and investigated through a cycle of ligand-FEP calculations, validating the binding orientation of the different chemical substituents proposed. Subsequent X-ray crystallography of the A2A AR with a low and a high affinity chromone derivative confirmed the predicted binding orientation. The new molecules and structures here reported were driven by free energy calculations, and provide new insights on antagonist binding to the A2A AR, an emerging target in immuno-oncology.
Assuntos
Antagonistas de Receptores Purinérgicos P1/química , Receptor A2A de Adenosina/química , Termodinâmica , Sítios de Ligação/efeitos dos fármacos , Cristalografia por Raios X , Humanos , Modelos Moleculares , Estrutura Molecular , Antagonistas de Receptores Purinérgicos P1/farmacologia , Receptor A2A de Adenosina/metabolismoRESUMO
OBJECTIVE: Blood/brain-glutamate grabbing is an emerging concept in the treatment of acute ischemic stroke, where essentially the deleterious effects of glutamate after ischemia are ameliorated by coaxing glutamate to enter the bloodstream and thus reducing its concentration in the brain. Aiming to demonstrate the clinical efficacy of blood glutamate grabbers in patients with stroke, in this study, we resorted to a drug-repositioning strategy for the discovery of new glutamate-grabbing drugs. METHODS: The glutamate-grabbing ability of 1,120 compounds (90% of which were drugs approved by the US Food and Drug Administration) was evaluated during an in vitro high-throughput screening campaign. Subsequently, the protective efficacy of the selected drugs was probed in an ischemic animal model and finally tested in stroke patients. RESULTS: Riboflavin (vitamin B2 ) was identified as the main hit compound. In ischemic animal models treated with riboflavin (1mg/kg), it was confirmed that blood glutamate reduction was associated with a significant reduction of infarct size. These results led to a randomized, double-blind, phase IIb clinical trial with patients with stroke. Fifty patients were randomized to 1 of the 2 study arms: the control group (placebo) and the experimental group (20mg of riboflavin [vitamin B2 Streuli@ ). Decrease in glutamate concentration was significantly greater (p < 0.029) in the treated group. Comparative analysis of the percentage improvement on the National Institutes of Health Stroke Scale score at discharge was slightly higher in the riboflavin-treated group than in the placebo group (33.7 ± 43.7 vs 48.9 ± 42.4%, p = 0.050). INTERPRETATION: This translational study represents the first human demonstration of the efficacy of blood glutamate grabbers in the treatment of patients with stroke, paving the way for the development of a promising novel protective therapy. Ann Neurol 2018;84:260-273.
Assuntos
Barreira Hematoencefálica/metabolismo , Isquemia Encefálica/sangue , Ácido Glutâmico/sangue , Acidente Vascular Cerebral/sangue , Animais , Barreira Hematoencefálica/efeitos dos fármacos , Isquemia Encefálica/diagnóstico , Isquemia Encefálica/tratamento farmacológico , Método Duplo-Cego , Feminino , Seguimentos , Humanos , Masculino , Ratos , Ratos Sprague-Dawley , Reprodutibilidade dos Testes , Riboflavina/farmacologia , Riboflavina/uso terapêutico , Acidente Vascular Cerebral/diagnóstico , Acidente Vascular Cerebral/tratamento farmacológico , Complexo Vitamínico B/farmacologia , Complexo Vitamínico B/uso terapêuticoRESUMO
Caffeine is a promising drug for the management of neurodegenerative diseases such as Parkinson's disease (PD), demonstrating neuroprotective properties that have been attributed to its interaction with the basal ganglia adenosine A2A receptor (A2AR). However, the doses needed to exert these neuroprotective effects may be too high. Thus, it is important to design novel approaches that selectively deliver this natural compound to the desired target. Docosahexaenoic acid (DHA) is the major omega-3 fatty acid in the brain and can act as a specific carrier of caffeine. Furthermore, DHA displays properties that may lead to its use as a neuroprotective agent. In the present study, we constructed a novel bivalent ligand covalently linking caffeine and DHA and assessed its pharmacological activity and safety profile in a simple cellular model. Interestingly, the new bivalent ligand presented higher potency as an A2AR inverse agonist than caffeine alone. We also determined the range of concentrations inducing toxicity both in a heterologous system and in primary striatal cultures. The novel strategy presented here of attaching DHA to caffeine may enable increased effects of the drug at desired sites, which could be of interest for the treatment of PD.
Assuntos
Agonistas do Receptor A2 de Adenosina/síntese química , Cafeína/farmacologia , Ácidos Docosa-Hexaenoicos/química , Fármacos Neuroprotetores/farmacologia , Agonistas do Receptor A2 de Adenosina/química , Agonistas do Receptor A2 de Adenosina/farmacologia , Cafeína/química , Células Cultivadas , Desenho de Fármacos , Agonismo Inverso de Drogas , Células HEK293 , Humanos , Estrutura Molecular , Neurônios/efeitos dos fármacos , Fármacos Neuroprotetores/químicaRESUMO
A practical, integrated and versatile U-4CR-based assembly of 1,4-benzodiazepin-2-ones exhibiting functionally, skeletally, and stereochemically diverse substitution patterns is described. By virtue of its convergence, atom economy, and bond-forming efficiency, the methodology documented herein exemplifies the reconciliation of structural complexity and experimental simplicity in the context of medicinal chemistry projects.
Assuntos
Benzodiazepinonas/química , Técnicas de Química Combinatória , Estrutura Molecular , Fenômenos de Química Orgânica , EstereoisomerismoRESUMO
An integrated multidisciplinary approach that combined structure-based drug design, multicomponent reaction synthetic approaches and functional characterization in enzymatic and cell assays led to the discovery of new kinesin spindle protein (KSP) inhibitors with antiproliferative activity. A focused library of new benzimidazoles obtained by a Ugi+Boc removal/cyclization reaction sequence generated low-micromolar-range KSP inhibitors as promising anticancer prototypes. The design and functional studies of the new chemotypes were assessed by computational modeling and molecular biology techniques. The most active compounds-20 (IC50 =1.49 µM, EC50 =3.63 µM) and 22 (IC50 =1.37 µM, EC50 =6.90 µM)-were synthesized with high efficiency by taking advantage of the multicomponent reactions.
Assuntos
Antineoplásicos/química , Antineoplásicos/farmacologia , Benzimidazóis/química , Benzimidazóis/farmacologia , Desenho de Fármacos , Cinesinas/antagonistas & inibidores , Antineoplásicos/síntese química , Benzimidazóis/síntese química , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Ensaios de Seleção de Medicamentos Antitumorais , Humanos , Cinesinas/química , Cinesinas/metabolismo , Simulação de Acoplamento Molecular , Neoplasias/tratamento farmacológico , Neoplasias/metabolismo , Bibliotecas de Moléculas Pequenas/síntese química , Bibliotecas de Moléculas Pequenas/química , Bibliotecas de Moléculas Pequenas/farmacologia , Relação Estrutura-AtividadeRESUMO
Antagonists of the A2B adenosine receptor have recently emerged as targeted anticancer agents and immune checkpoint inhibitors within the realm of cancer immunotherapy. This study presents a comprehensive evaluation of novel Biginelli-assembled pyrimidine chemotypes, including mono-, bi-, and tricyclic derivatives, as A2BAR antagonists. We conducted a comprehensive examination of the adenosinergic profile (both binding and functional) of a large compound library consisting of 168 compounds. This approach unveiled original lead compounds and enabled the identification of novel structure-activity relationship (SAR) trends, which were supported by extensive computational studies, including quantum mechanical calculations and free energy perturbation (FEP) analysis. In total, 25 molecules showed attractive affinity (Ki < 100â¯nM) and outstanding selectivity for A2BAR. From these, five molecules corresponding to the new benzothiazole scaffold were below the Ki < 10â¯nM threshold, in addition to a novel dual A2A/A2B antagonist. The most potent compounds, and the dual antagonist, showed enantiospecific recognition in the A2BAR. Two A2BAR selective antagonists and the dual A2AAR/A2BAR antagonist reported in this study were assessed for their impact on colorectal cancer cell lines. The results revealed a significant and dose-dependent reduction in cell proliferation. Notably, the A2BAR antagonists exhibited remarkable specificity, as they did not impede the proliferation of non-tumoral cell lines. These findings support the efficacy and potential that A2BAR antagonists as valuable candidates for cancer therapy, but also that they can effectively complement strategies involving A2AAR antagonism in the context of immune checkpoint inhibition.
Assuntos
Antineoplásicos , Neoplasias Colorretais , Humanos , Antagonistas de Receptores Purinérgicos P1 , Receptor A2B de Adenosina/metabolismo , Antagonistas do Receptor A2 de Adenosina/farmacologia , Relação Estrutura-Atividade , Antineoplásicos/farmacologia , Neoplasias Colorretais/tratamento farmacológicoRESUMO
An expedient and concise Ugi-based approach for the rapid assembly of pyrazin-2(1H)-one-based frameworks has been developed. This convergent approach encompasses skeletal, functional and stereochemical diversity, exhibiting an unusually high bond-forming efficiency as well as high structure and step economies. The method involves the use of readily available commercial reagents and is an example of the reconciliation of structural complexity with operational simplicity in a time- and cost-effective manner.
Assuntos
Pirazinas/síntese química , Técnicas de Química Combinatória , Cristalografia por Raios X , Ciclização , Descoberta de Drogas , Estrutura Molecular , Pirazinas/química , EstereoisomerismoRESUMO
We herein document the first example of a reliable copper-catalyzed Huisgen 1,3-dipolar cycloaddition under oxidative conditions. The combined use of two polymer-supported reagents (polystyrene-1,5,7-triazabicyclo[4,4,0]dec-5-ene/Cu and polystyrene-2-iodoxybenzamide) overcomes the thermodynamic instability of copper(I) species toward oxidation, enabling the reliable Cu-catalyzed Huisgen 1,3-dipolar cycloadditions in the presence of an oxidant agent. This polymer-assisted pathway, not feasible under conventional homogeneous conditions, provides a direct assembly of 4-acyl-1-substituted-1,2,3-triazoles, contributing to expand the reliability and scope of Cu(I)-catalyzed alkyne-azide cycloaddition.
Assuntos
Alcinos/química , Azidas/química , Cobre/química , Poliestirenos/química , Triazóis/síntese química , Catálise , Ciclização , Estrutura Molecular , Oxirredução , Termodinâmica , Triazóis/químicaRESUMO
Synthetic cannabinoid receptor agonists (SCRAs) constitute the largest and most defiant group of abuse designer drugs. These new psychoactive substances (NPS), developed as unregulated alternatives to cannabis, have potent cannabimimetic effects and their use is usually associated with episodes of psychosis, seizures, dependence, organ toxicity and death. Due to their ever-changing structure, very limited or nil structural, pharmacological, and toxicological information is available to the scientific community and the law enforcement offices. Here we report the synthesis and pharmacological evaluation (binding and functional) of the largest and most diverse collection of enantiopure SCRAs published to date. Our results revealed novel SCRAs that could be (or may currently be) used as illegal psychoactive substances. We also report, for the first time, the cannabimimetic data of 32 novel SCRAs containing an (R) configuration at the stereogenic center. The systematic pharmacological profiling of the library enabled the identification of emerging Structure-Activity Relationship (SAR) and Structure-Selectivity Relationship (SSR) trends, the detection of ligands exhibiting incipient cannabinoid receptor type 2 (CB2R) subtype selectivity and highlights the significant neurotoxicity of representative SCRAs on mouse primary neuronal cells. Several of the new emerging SCRAs are currently expected to have a rather limited potential for harm, as the evaluation of their pharmacological profiles revealed lower potencies and/or efficacies. Conceived as a resource to foster collaborative investigation of the physiological effects of SCRAs, the library obtained can contribute to addressing the challenge posed by recreational designer drugs.
Assuntos
Cannabis , Drogas Desenhadas , Animais , Camundongos , Agonistas de Receptores de Canabinoides/farmacologia , Drogas Desenhadas/toxicidade , Relação Estrutura-Atividade , LigantesRESUMO
The modulation of the A2B adenosine receptor is a promising strategy in cancer (immuno) therapy, with A2BAR antagonists emerging as immune checkpoint inhibitors. Herein, we report a systematic assessment of the impact of (di- and mono-)halogenation at positions 7 and/or 8 on both A2BAR affinity and pharmacokinetic properties of a collection of A2BAR antagonists and its study with structure-based free energy perturbation simulations. Monohalogenation at position 8 produced potent A2BAR ligands irrespective of the nature of the halogen. In contrast, halogenation at position 7 and dihalogenation produced a halogen-size-dependent decay in affinity. Eight novel A2BAR ligands exhibited remarkable affinity (Ki < 10 nM), exquisite subtype selectivity, and enantioselective recognition, with some eutomers eliciting sub-nanomolar affinity. The pharmacokinetic profile of representative derivatives showed enhanced solubility and microsomal stability. Finally, two compounds showed the capacity of reversing the antiproliferative effect of adenosine in activated primary human peripheral blood mononuclear cells.
Assuntos
Halogenação , Antagonistas de Receptores Purinérgicos P1 , Cricetinae , Animais , Humanos , Células CHO , Leucócitos Mononucleares/metabolismo , Antagonistas do Receptor A2 de Adenosina/farmacologia , Receptor A2B de Adenosina/metabolismo , Ligantes , HalogêniosRESUMO
BACKGROUND: Adenosine is a metabolite that suppresses antitumor immune response of T and NK cells via extracellular binding to the two subtypes of adenosine-2 receptors, A2ARs. While blockade of the A2AARs subtype effectively rescues lymphocyte activity, with four A2AAR antagonists currently in anticancer clinical trials, less is known for the therapeutic potential of the other A2BAR blockade within cancer immunotherapy. Recent studies suggest the formation of A2AAR/A2BAR dimers in tissues that coexpress the two receptor subtypes, where the A2BAR plays a dominant role, suggesting it as a promising target for cancer immunotherapy. METHODS: We report the synthesis and functional evaluation of five potent A2BAR antagonists and a dual A2AAR/A2BAR antagonist. The compounds were designed using previous pharmacological data assisted by modeling studies. Synthesis was developed using multicomponent approaches. Flow cytometry was used to evaluate the phenotype of T and NK cells on A2BAR antagonist treatment. Functional activity of T and NK cells was tested in patient-derived tumor spheroid models. RESULTS: We provide data for six novel small molecules: five A2BAR selective antagonists and a dual A2AAR/A2BAR antagonist. The growth of patient-derived breast cancer spheroids is prevented when treated with A2BAR antagonists. To elucidate if this depends on increased lymphocyte activity, immune cells proliferation, and cytokine production, lymphocyte infiltration was evaluated and compared with the potent A2AAR antagonist AZD-4635. We find that A2BAR antagonists rescue T and NK cell proliferation, IFNγ and perforin production, and increase tumor infiltrating lymphocytes infiltration into tumor spheroids without altering the expression of adhesion molecules. CONCLUSIONS: Our results demonstrate that A2BAR is a promising target in immunotherapy, identifying ISAM-R56A as the most potent candidate for A2BAR blockade. Inhibition of A2BAR signaling restores T cell function and proliferation. Furthermore, A2BAR and dual A2AAR/A2BAR antagonists showed similar or better results than A2AAR antagonist AZD-4635 reinforcing the idea of dominant role of the A2BAR in the regulation of the immune system.
Assuntos
Neoplasias , Antagonistas de Receptores Purinérgicos P1 , Adenosina/farmacologia , Humanos , Linfócitos/metabolismo , Neoplasias/tratamento farmacológico , Receptor A2B de Adenosina/genética , Receptor A2B de Adenosina/metabolismoRESUMO
We herein document a large collection of 108 2-amino-4,6-disubstituted-pyrimidine derivatives as potent, structurally simple, and highly selective A1AR ligands. The most attractive ligands were confirmed as antagonists of the canonical cyclic adenosine monophosphate pathway, and some pharmacokinetic parameters were preliminarilly evaluated. The library, built through a reliable and efficient three-component reaction, comprehensively explored the chemical space allowing the identification of the most prominent features of the structure-activity and structure-selectivity relationships around this scaffold. These included the influence on the selectivity profile of the aromatic residues at positions R4 and R6 of the pyrimidine core but most importantly the prominent role to the unprecedented A1AR selectivity profile exerted by the methyl group introduced at the exocyclic amino group. The structure-activity relationship trends on both A1 and A2AARs were conveniently interpreted with rigorous free energy perturbation simulations, which started from the receptor-driven docking model that guided the design of these series.
Assuntos
Antagonistas do Receptor A1 de Adenosina/química , Pirimidinas/química , Antagonistas do Receptor A1 de Adenosina/metabolismo , Antagonistas do Receptor A1 de Adenosina/farmacocinética , Sítios de Ligação , Linhagem Celular , Desenho de Fármacos , Estabilidade de Medicamentos , Humanos , Cinética , Simulação de Acoplamento Molecular , Pirimidinas/metabolismo , Pirimidinas/farmacocinética , Receptor A1 de Adenosina/química , Receptor A1 de Adenosina/metabolismo , Receptor A2A de Adenosina/química , Receptor A2A de Adenosina/metabolismo , Relação Estrutura-AtividadeRESUMO
A library of potent and highly A3AR selective pyrimidine-based compounds was designed to explore non-orthosteric interactions within this receptor. Starting from a prototypical orthosteric A3AR antagonist (ISVY130), the structure-based design explored functionalized residues at the exocyclic amide L1 region and aimed to provide additional interactions outside the A3AR orthosteric site. The novel ligands were assembled through an efficient and succinct synthetic approach, resulting in compounds that retain the A3AR potent and selective profile while improving the solubility of the original scaffold. The experimentally demonstrated tolerability of the L1 region to structural functionalization was further assessed by molecular dynamics simulations, giving hints of the non-orthosteric interactions explored by these series. The results pave the way to explore newly functionalized A3AR ligands, including covalent drugs and molecular probes for diagnostic and delivery purposes.
RESUMO
Using a previously unexplored, efficient, and versatile multicomponent method, we herein report the rapid generation of novel potent and subtype-selective DRD2 biased partial agonists. This strategy exemplifies the search for diverse and previously unexplored moieties for the secondary/allosteric pharmacophore of the common phenyl-piperazine scaffold. The pharmacological characterization of the new compound series led to the identification of several ligands with excellent DRD2 affinity and subtype selectivity and remarkable functional selectivity for either the cAMP (22a and 24d) or the ß-arrestin (27a and 29c) signaling pathways. These results were further interpreted on the basis of molecular models of these ligands in complex with the recent DRD2 crystal structures, highlighting the critical role of the secondary/allosteric pharmacophore in modulating the functional selectivity profile.
Assuntos
Piperazinas/farmacologia , Receptores de Dopamina D2/agonistas , AMP Cíclico/metabolismo , Desenho de Fármacos , Agonismo Parcial de Drogas , Células HEK293 , Humanos , Simulação de Acoplamento Molecular , Estrutura Molecular , Piperazinas/síntese química , Piperazinas/metabolismo , Receptores de Dopamina D2/metabolismo , Transdução de Sinais/efeitos dos fármacos , Relação Estrutura-Atividade , beta-Arrestinas/metabolismoRESUMO
We present and thoroughly characterize a large collection of 3,4-dihydropyrimidin-2(1H)-ones as A2BAR antagonists, an emerging strategy in cancer (immuno) therapy. Most compounds selectively bind A2BAR, with a number of potent and selective antagonists further confirmed by functional cyclic adenosine monophosphate experiments. The series was analyzed with one of the most exhaustive free energy perturbation studies on a GPCR, obtaining an accurate model of the structure-activity relationship of this chemotype. The stereospecific binding modeled for this scaffold was confirmed by resolving the two most potent ligands [(±)-47, and (±)-38 Ki = 10.20 and 23.6 nM, respectively] into their two enantiomers, isolating the affinity on the corresponding (S)-eutomers (Ki = 6.30 and 11.10 nM, respectively). The assessment of the effect in representative cytochromes (CYP3A4 and CYP2D6) demonstrated insignificant inhibitory activity, while in vitro experiments in three prostate cancer cells demonstrated that this pair of compounds exhibits a pronounced antimetastatic effect.
Assuntos
Antagonistas do Receptor A2 de Adenosina/farmacologia , Pirimidinas/farmacologia , Receptor A2B de Adenosina/efeitos dos fármacos , Antagonistas do Receptor A2 de Adenosina/metabolismo , Animais , Células CHO , Cricetulus , AMP Cíclico/metabolismo , Células HEK293 , Células HeLa , Humanos , Modelos Moleculares , Metástase Neoplásica/prevenção & controle , Pirimidinas/química , Pirimidinas/metabolismo , Ensaio Radioligante , Receptor A2B de Adenosina/metabolismo , Estereoisomerismo , Relação Estrutura-AtividadeRESUMO
A systematic exploration of bioisosteric replacements for furan and thiophene cores in a series of potent A2BAR antagonists has been carried out using the nitrogen-walk approach. A collection of 42 novel alkyl 4-substituted-2-methyl-1,4-dihydrobenzo[4,5]imidazo[1,2-a]pyrimidine-3-carboxylates, which contain 18 different pentagonal heterocyclic frameworks at position 4, was synthesized and evaluated. This study enabled the identification of new ligands that combine remarkable affinity (Ki < 30 nM) and exquisite selectivity. The structure-activity relationship (SAR) trends identified were substantiated by a molecular modeling study, based on a receptor-driven docking model and including a systematic free energy perturbation (FEP) study. Preliminary evaluation of the CYP3A4 and CYP2D6 inhibitory activity in optimized ligands evidenced weak and negligible activity, respectively. The stereospecific interaction between hA2BAR and the eutomer of the most attractive novel antagonist (S)-18g (Ki = 3.66 nM) was validated.
Assuntos
Antagonistas do Receptor A2 de Adenosina/farmacologia , Imidazóis/farmacologia , Pirimidinas/farmacologia , Receptor A2B de Adenosina/metabolismo , Antagonistas do Receptor A2 de Adenosina/síntese química , Antagonistas do Receptor A2 de Adenosina/metabolismo , Animais , Células CHO , Linhagem Celular Tumoral , Cricetulus , Inibidores do Citocromo P-450 CYP2D6/síntese química , Inibidores do Citocromo P-450 CYP2D6/metabolismo , Inibidores do Citocromo P-450 CYP2D6/farmacologia , Inibidores do Citocromo P-450 CYP3A/síntese química , Inibidores do Citocromo P-450 CYP3A/metabolismo , Inibidores do Citocromo P-450 CYP3A/farmacologia , Humanos , Imidazóis/síntese química , Imidazóis/metabolismo , Simulação de Acoplamento Molecular , Estrutura Molecular , Pirimidinas/síntese química , Pirimidinas/metabolismo , Estereoisomerismo , Relação Estrutura-AtividadeRESUMO
We report the identification of two subsets of fluorinated nonxanthine A2B adenosine receptor antagonists. The novel derivatives explore the effect of fluorination at different positions of two pyrimidine-based scaffolds. The most interesting ligands combine excellent hA2B affinity (Ki < 15 nM) and remarkable subtype selectivity. The results of functional cAMP experiments confirmed the antagonistic behavior of representative ligands. The compounds were designed on the basis of previous molecular models of the stereoselective binding of the parent scaffolds to the hA2B receptor, and we herein provide refinement of such models with the fluorinated compounds, which allows the explanation of the spurious effects of the fluorination at the different positions explored. These models are importantly confirmed by a synergistic study combining chiral HPLC, circular dichroism, diastereoselective synthesis, molecular modeling, and X-ray crystallography, providing experimental evidence toward the stereospecific interaction between optimized trifluorinated stereoisomers and the hA2B receptor.
Assuntos
Antagonistas do Receptor A2 de Adenosina/química , Pirimidinas/química , Receptor A2B de Adenosina/química , Antagonistas do Receptor A2 de Adenosina/metabolismo , Sítios de Ligação , Cristalografia por Raios X , Desenho de Fármacos , Humanos , Ligação de Hidrogênio , Ligantes , Conformação Molecular , Simulação de Dinâmica Molecular , Isoformas de Proteínas/antagonistas & inibidores , Isoformas de Proteínas/genética , Isoformas de Proteínas/metabolismo , Pirimidinas/metabolismo , Receptor A2B de Adenosina/genética , Receptor A2B de Adenosina/metabolismo , Estereoisomerismo , Relação Estrutura-AtividadeRESUMO
We report the first family of 2-acetamidopyridines as potent and selective A3 adenosine receptor (AR) antagonists. The computer-assisted design was focused on the bioisosteric replacement of the N1 atom by a CH group in a previous series of diarylpyrimidines. Some of the generated 2-acetamidopyridines elicit an antagonistic effect with excellent affinity (Ki < 10 nM) and outstanding selectivity profiles, providing an alternative and simpler chemical scaffold to the parent series of diarylpyrimidines. In addition, using molecular dynamics and free energy perturbation simulations, we elucidate the effect of the second nitrogen of the parent diarylpyrimidines, which is revealed as a stabilizer of a water network in the binding site. The discovery of 2,6-diaryl-2-acetamidopyridines represents a step forward in the search of chemically simple, potent, and selective antagonists for the hA3AR, and exemplifies the benefits of a joint theoretical-experimental approach to identify novel hA3AR antagonists through succinct and efficient synthetic methodologies.
Assuntos
Acetamidas/química , Acetamidas/farmacologia , Antagonistas do Receptor A3 de Adenosina/química , Antagonistas do Receptor A3 de Adenosina/farmacologia , Receptor A3 de Adenosina/metabolismo , Animais , Sítios de Ligação , Células CHO , Desenho Assistido por Computador , Cricetulus , Desenho de Fármacos , Humanos , Simulação de Acoplamento Molecular , Nitrogênio/química , Nitrogênio/farmacologia , Pirimidinas/química , Pirimidinas/farmacologia , Receptor A3 de Adenosina/química , Relação Estrutura-AtividadeRESUMO
A novel family of structurally simple, potent, and selective nonxanthine A2BAR ligands was identified, and its antagonistic behavior confirmed through functional experiments. The reported alkyl 2-cyanoimino-4-substituted-6-methyl-1,2,3,4-tetrahy-dropyrimidine-5-carboxylates (16) were designed by bioisosteric replacement of the carbonyl group at position 2 in a series of 3,4-dihydropyrimidin-2-ones. The scaffold (16) documented herein contains a chiral center at the heterocycle. Accordingly, the most attractive ligand of the series [(±)16b, Ki = 24.3 nM] was resolved into its two enantiomers by chiral HPLC, and the absolute configuration was established by circular dichroism. The biological evaluation of both enantiomers demonstrated enantiospecific recognition at A2BAR, with the (S)-16b enantiomer retaining all the affinity (Ki = 15.1 nM), as predicted earlier by molecular modeling. This constitutes the first example of enantiospecific recognition at the A2B adenosine receptor and opens new possibilities in ligand design for this receptor.
Assuntos
Pirimidinas/química , Receptor A2B de Adenosina/química , Espectroscopia de Ressonância Magnética Nuclear de Carbono-13 , Espectroscopia de Prótons por Ressonância Magnética , Espectrometria de Massas por Ionização por Electrospray , EstereoisomerismoRESUMO
Compounds designed to display polypharmacology may have utility in treating complex diseases, where activity at multiple targets is required to produce a clinical effect. In particular, suitable compounds may be useful in treating neurodegenerative diseases by promoting neuronal survival in a synergistic manner via their multi-target activity at the adenosine A1 and A2A receptors (A1R and A2AR) and phosphodiesterase 10A (PDE10A), which modulate intracellular cAMP levels. Hence, in this work we describe a computational method for the design of synthetically feasible ligands that bind to A1 and A2A receptors and inhibit phosphodiesterase 10A (PDE10A), involving a retrosynthetic approach employing in silico target prediction and docking, which may be generally applicable to multi-target compound design at several target classes. This approach has identified 2-aminopyridine-3-carbonitriles as the first multi-target ligands at A1R, A2AR and PDE10A, by showing agreement between the ligand and structure based predictions at these targets. The series were synthesized via an efficient one-pot scheme and validated pharmacologically as A1R/A2AR-PDE10A ligands, with IC50 values of 2.4-10.0 µM at PDE10A and Ki values of 34-294 nM at A1R and/or A2AR. Furthermore, selectivity profiling of the synthesized 2-amino-pyridin-3-carbonitriles against other subtypes of both protein families showed that the multi-target ligand 8 exhibited a minimum of twofold selectivity over all tested off-targets. In addition, both compounds 8 and 16 exhibited the desired multi-target profile, which could be considered for further functional efficacy assessment, analog modification for the improvement of selectivity towards A1R, A2AR and PDE10A collectively, and evaluation of their potential synergy in modulating cAMP levels.