| 1. |
- Azuaje, Jhonny, et al.
(author)
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Effect of Nitrogen Atom Substitution in A(3) Adenosine Receptor Binding : N-(4,6-Diarylpyridin-2-yl)acetamides as Potent and Selective Antagonists
- 2017
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In: Journal of Medicinal Chemistry. - : American Chemical Society (ACS). - 0022-2623 .- 1520-4804. ; 60:17, s. 7502-7511
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Journal article (peer-reviewed)abstract
- We report the first family of 2-acetamidopyridines as potent and selective A, 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 (K-j < 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 hA(3)AR, and exemplifies the benefits of a joint theoretical- experimental approach to identify novel hA(3)AR antagonists through succinct and efficient synthetic methodologies.
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| 2. |
- Majellaro, María, et al.
(author)
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3,4-Dihydropyrimidin-2(1H)-ones as Antagonists of the Human A2B Adenosine Receptor : Optimization, Structure–Activity Relationship Studies, and Enantiospecific Recognition
- 2021
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In: Journal of Medicinal Chemistry. - : American Chemical Society (ACS). - 0022-2623 .- 1520-4804. ; 64:1, s. 458-480
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Journal article (peer-reviewed)abstract
- 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 (±)-38Ki = 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.
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| 3. |
- Crespo, Abel, et al.
(author)
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Exploring the influence of the substituent at position 4 in a series of 3,4-dihydropyrimidin-2(1H)-one A(2B) adenosine receptor antagonists
- 2017
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In: Chemistry of Heterocyclic Compounds. - : Springer. - 0009-3122 .- 1573-8353. ; 53:3, s. 316-321
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Journal article (peer-reviewed)abstract
- In the context of a program to identify selective adenosine A(2B) receptor antagonists, we have obtained a focused library of 4-substituted 3,4-dihydropyrimidin-2(1H)-ones and its affinity for the four human adenosine receptor subtypes was determined. The synthesis was accomplished by using an experimentally simple and efficient Biginelli approach. The biological evaluation of the library revealed that all the documented derivatives exhibit low or negligible affinity for the A(2B) receptor, thus highlighting the critical importance of the substituent at position 4 of the 3,4-dihydropyrimidin-2(1H)-one chemotype.
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| 4. |
- Mallo-Abreu, Ana, et al.
(author)
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Nitrogen-Walk Approach to Explore Bioisosteric Replacements in a Series of Potent A(2B) Adenosine Receptor Antagonists
- 2020
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In: Journal of Medicinal Chemistry. - : American Chemical Society (ACS). - 0022-2623 .- 1520-4804. ; 63:14, s. 7721-7739
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Journal article (peer-reviewed)abstract
- A systematic exploration of bioisosteric replacements for furan and thiophene cores in a series of potent A(2B)AR 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 (K-i < 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 hA(2B)AR and the eutomer of the most attractive novel antagonist (S)-18g (K-i = 3.66 nM) was validated.
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| 5. |
- Mallo-Abreu, Ana, et al.
(author)
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Trifluorinated Pyrimidine-Based A(2B) Antagonists : Optimization and Evidence of Stereospecific Recognition
- 2019
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In: Journal of Medicinal Chemistry. - : AMER CHEMICAL SOC. - 0022-2623 .- 1520-4804. ; 62:20, s. 9315-9330
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Journal article (peer-reviewed)abstract
- We report the identification of two subsets of fluorinated nonxanthine A(2B) 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 hA(2B) affinity (K-i < 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 hA(2B) 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 hA(2B) receptor.
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| 6. |
- Prieto-Diaz, Ruben, et al.
(author)
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Exploring Biginelli-based scaffolds as A2B adenosine receptor antagonists : Unveiling novel structure-activity relationship trends, lead compounds, and potent colorectal anticancer agents
- 2024
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In: Biomedicine and Pharmacotherapy. - : Elsevier. - 0753-3322 .- 1950-6007. ; 173
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Journal article (peer-reviewed)abstract
- 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 < 100 nM) and outstanding selectivity for A2BAR. From these, five molecules corresponding to the new benzothiazole scaffold were below the Ki < 10 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.
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| 7. |
- Prieto-Díaz, Rubén, et al.
(author)
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Exploring the Effect of Halogenation in a Series of Potent and Selective A2B Adenosine Receptor Antagonists
- 2023
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In: Journal of Medicinal Chemistry. - : American Chemical Society (ACS). - 0022-2623 .- 1520-4804. ; 66:1, s. 890-912
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Journal article (peer-reviewed)abstract
- 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.
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| 8. |
- Tay, Apple Hui Min, et al.
(author)
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A(2B) adenosine receptor antagonists rescue lymphocyte activity in adenosine-producing patient-derived cancer models
- 2022
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In: Journal for ImmunoTherapy of Cancer. - : BMJ. - 2051-1426. ; 10:5, s. e004592-
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Journal article (peer-reviewed)abstract
- 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, A(2)ARs. While blockade of the A(2A)ARs subtype effectively rescues lymphocyte activity, with four A(2A)AR antagonists currently in anticancer clinical trials, less is known for the therapeutic potential of the other A(2B)AR blockade within cancer immunotherapy. Recent studies suggest the formation of A(2A)AR/A(2B)AR dimers in tissues that coexpress the two receptor subtypes, where the A(2B)AR plays a dominant role, suggesting it as a promising target for cancer immunotherapy. Methods We report the synthesis and functional evaluation of five potent A(2B)AR antagonists and a dual A(2A)AR/A(2B)AR 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 A(2B)AR 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 A(2B)AR selective antagonists and a dual A(2A)AR/A(2B)AR antagonist. The growth of patient-derived breast cancer spheroids is prevented when treated with A(2B)AR 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 A(2A)AR antagonist AZD-4635. We find that A(2B)AR antagonists rescue T and NK cell proliferation, IFN gamma and perforin production, and increase tumor infiltrating lymphocytes infiltration into tumor spheroids without altering the expression of adhesion molecules. Conclusions Our results demonstrate that A(2B)AR is a promising target in immunotherapy, identifying ISAM-R56A as the most potent candidate for A(2B)AR blockade. Inhibition of A(2B)AR signaling restores T cell function and proliferation. Furthermore, A(2B)AR and dual A(2A)AR/A(2B)AR antagonists showed similar or better results than A(2A)AR antagonist AZD-4635 reinforcing the idea of dominant role of the A(2B)AR in the regulation of the immune system.
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| 9. |
- Val, Cristina, et al.
(author)
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Optimization of 2-Amino-4,6-diarylpyrimidine-5-carbonitriles as Potent and Selective A(1) Antagonists
- 2022
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In: Journal of Medicinal Chemistry. - : American Chemical Society (ACS). - 0022-2623 .- 1520-4804. ; 65:3, s. 2091-2106
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Journal article (peer-reviewed)abstract
- We herein document a large collection of 108 2-amino-4,6-disubstituted-pyrimidine derivatives as potent, structurally simple, and highly selective A(1)AR ligands. The most attractive ligands were confirmed as antagonists of the canonical cyclic adenosine monophosphate pathway, and some pharmacokinetic parameters were preliminarily 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 R-4 and R-6 of the pyrimidine core but most importantly the prominent role to the unprecedented A(1)AR selectivity profile exerted by the methyl group introduced at the exocyclic amino group. The structure-activity relationship trends on both A(1) and A(2A)ARs were conveniently interpreted with rigorous free energy perturbation simulations, which started from the receptor-driven docking model that guided the design of these series.
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| 10. |
- Jespers, Willem, et al.
(author)
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Structure-Based Design of Potent and Selective Ligands at the Four Adenosine Receptors
- 2017
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In: Molecules. - : MDPI AG. - 1431-5157 .- 1420-3049. ; 22:11
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Journal article (peer-reviewed)abstract
- The four receptors that signal for adenosine, A(1), A(2A), A(2B) and A(3) ARs, belong to the superfamily of G protein-coupled receptors (GPCRs). They mediate a number of (patho)physiological functions and have attracted the interest of the biopharmaceutical sector for decades as potential drug targets. The many crystal structures of the A(2A), and lately the A(1) ARs, allow for the use of advanced computational, structure-based ligand design methodologies. Over the last decade, we have assessed the efficient synthesis of novel ligands specifically addressed to each of the four ARs. We herein review and update the results of this program with particular focus on molecular dynamics (MD) and free energy perturbation (FEP) protocols. The first in silico mutagenesis on the A(1)AR here reported allows understanding the specificity and high affinity of the xanthine-antagonist 8-Cyclopentyl-1,3-dipropylxanthine (DPCPX). On the A(2A)AR, we demonstrate how FEP simulations can distinguish the conformational selectivity of a recent series of partial agonists. These novel results are complemented with the revision of the first series of enantiospecific antagonists on the A(2B)AR, and the use of FEP as a tool for bioisosteric design on the A(3)AR.
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