Exploring Non-orthosteric Interactions with a Series of Potent and Selective A₃ Antagonists

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This article references 24 other publications.

1. 1

   Fredholm, B. B. Adenosine, an Endogenous Distress Signal, Modulates Tissue Damage and Repair. Cell Death Differ. 2007, 14 (7), 1315– 1323,  DOI: 10.1038/sj.cdd.4402132

   Google Scholar

   1

   Adenosine, an endogenous distress signal, modulates tissue damage and repair

   Fredholm, B. B.

   Cell Death and Differentiation (2007), 14 (7), 1315-1323CODEN: CDDIEK; ISSN:1350-9047. (Nature Publishing Group)

   A review. Adenosine is formed inside cells or on their surface, mostly by breakdown of adenine nucleotides. The formation of adenosine increases in different conditions of stress and distress. Adenosine acts on four G-protein coupled receptors: two of them, A1 and A3, are primarily coupled to Gi family G proteins; and two of them, A2A and A2B, are mostly coupled to Gs like G proteins. These receptors are antagonized by xanthines including caffeine. Via these receptors it affects many cells and organs, usually having a cytoprotective function. Joel Linden recently grouped these protective effects into four general modes of action: increased oxygen supply/demand ratio, preconditioning, anti-inflammatory effects and stimulation of angiogenesis. This review will briefly summarize what is known and what is not in this regard. It is argued that drugs targeting adenosine receptors might be useful adjuncts in many therapeutic approaches.
2. 2

   Fredholm, B. B.; Ijzerman, A. P.; Jacobson, K. A.; Linden, J.; Müller, C. E. International Union of Basic and Clinical Pharmacology. LXXXI. Nomenclature and Classification of Adenosine Receptors-An Update. Pharmacol. Rev. 2011, 63 (1), 1– 34,  DOI: 10.1124/pr.110.003285

   Google Scholar

   2

   International union of basic and clinical pharmacology. LXXXI. Nomenclature and classification of adenosine receptors - an update

   Fredholm, Bertil B.; IJzerman, Adriaan P.; Jacobson, Kenneth A.; Linden, Joel; Mueller, Christa E.

   Pharmacological Reviews (2011), 63 (1), 1-34CODEN: PAREAQ; ISSN:0031-6997. (American Society for Pharmacology and Experimental Therapeutics)

   A review. In the 10 years since our previous International Union of Basic and Clin. Pharmacol. report on the nomenclature and classification of adenosine receptors, no developments have led to major changes in the recommendations. However, there have been so many other developments that an update is needed. The fact that the structure of one of the adenosine receptors has recently been solved has already led to new ways of in silico screening of ligands. The evidence that adenosine receptors can form homo- and hetero-multimers has accumulated, but the functional significance of such complexes remains unclear. The availability of mice with genetic modification of all the adenosine receptors has led to a clarification of the functional roles of adenosine, and to excellent means to study the specificity of drugs. There are also interesting assocns. between disease and structural variants in one or more of the adenosine receptors. Several new selective agonists and antagonists have become available. They provide improved possibilities for receptor classification. There are also developments hinting at the usefulness of allosteric modulators. Many drugs targeting adenosine receptors are in clin. trials, but the established therapeutic use is still very limited.
3. 3

   Fredholm, B. B.; IJzerman, A. P.; Jacobson, K. A.; Klotz, K.; Linden, J. International Union of Basic and Clinical Pharmacology. XXV. Nomenclature and Classification of Adenosine Receptors. Pharmacol. Rev. 2001, 53 (4), 527– 247

   Google Scholar

   3

   International union of pharmacology. XXV. Nomenclature and classification of adenosine receptors

   Fredholm, Bertil B.; IJzerman, Adriaan P.; Jacobson, Kenneth A.; Klotz, Karl-Norbert; Linden, Joel

   Pharmacological Reviews (2001), 53 (4), 527-552CODEN: PAREAQ; ISSN:0031-6997. (American Society for Pharmacology and Experimental Therapeutics)

   A review. Four adenosine receptors have been cloned and characterized from several mammalian species. The receptors are named adenosine A1, A2A, A2B, and A3. The A2A and A2B receptors preferably interact with members of the Gs family of G proteins and the A1 and A3 receptors with Gi/o proteins. However, other G protein interactions have also been described. Adenosine is the preferred endogenous agonist at all these receptors, but inosine can also activate the A3 receptor. The levels of adenosine seen under basal conditions are sufficient to cause some activation of all the receptors, at least where they are abundantly expressed. Adenosine levels during, e.g., ischemia can activate all receptors even when expressed in low abundance. Accordingly, expts. with receptor antagonists and mice with targeted disruption of adenosine A1, A2A, and A3 expression reveal roles for these receptors under physiol. and particularly pathophysiol. conditions. There are pharmacol. tools that can be used to classify A1, A2A, and A3 receptors but few drugs that interact selectively with A2B receptors. Testable models of the interaction of these drugs with their receptors have been generated by site-directed mutagenesis and homol.-based modeling. Both agonists and antagonists are being developed as potential drugs.
4. 4

   Fredholm, B. B. Adenosine - A Physiological or Pathophysiological Agent?. J. Mol. Med. 2014, 92 (3), 201– 206,  DOI: 10.1007/s00109-013-1101-6

   Google Scholar

   4

   Adenosine-a physiological or pathophysiological agent?

   Fredholm, Bertil B.

   Journal of Molecular Medicine (Heidelberg, Germany) (2014), 92 (3), 201-206CODEN: JMLME8; ISSN:0946-2716. (Springer)

   A review. This minireview briefly summarizes the evidence that adenosine, acting on four G-protein coupled receptors, can play physiol. roles, but is also critically involved in pathol. processes. The factors that decide which of these is the more important in a specific cell or organ are briefly summarized. The fact that drugs that target adenosine receptors in disease will also hit the physiol. processes will make drug development more tricky.
5. 5

   Borea, P. A.; Gessi, S.; Merighi, S.; Vincenzi, F.; Varani, K. Pharmacology of Adenosine Receptors: The State of the Art. Physiol. Rev. 2018, 98 (3), 1591– 1625,  DOI: 10.1152/physrev.00049.2017

   Google Scholar

   5

   Pharmacology of adenosine receptors: the state of the art

   Borea, Pier Andrea; Gessi, Stefania; Merighi, Stefania; Vincenzi, Fabrizio; Varani, Katia

   Physiological Reviews (2018), 98 (3), 1591-1625CODEN: PHREA7; ISSN:1522-1210. (American Physiological Society)

   A review. Adenosine is a ubiquitous endogenous autacoid whose effects are triggered through the enrollment of four G protein-coupled receptors: A1, A2A, A2B, and A3. Due to the rapid generation of adenosine from cellular metab., and the widespread distribution of its receptor subtypes in almost all organs and tissues, this nucleoside induces a multitude of physiopathol. effects, regulating central nervous, cardiovascular, peripheral, and immune systems. It is becoming clear that the expression patterns of adenosine receptors vary among cell types, lending wt. to the idea that they may be both markers of pathologies and useful targets for novel drugs. This review offers an overview of current knowledge on adenosine receptors, including their characteristic structural features, mol. interactions and cellular functions, as well as their essential roles in pain, cancer, and neurodegenerative, inflammatory, and autoimmune diseases. Finally, we highlight the latest findings on mols. capable of targeting adenosine receptors and report which stage of drug development they have reached.
6. 6

   Borea, P. A.; Gessi, S.; Merighi, S.; Vincenzi, F.; Varani, K. Pathological Overproduction: The Bad Side of Adenosine. Br. J. Pharmacol. 2017, 174 (13), 1945– 1960,  DOI: 10.1111/bph.13763

   Google Scholar

   6

   Pathological overproduction: the bad side of adenosine

   Borea, Pier Andrea; Gessi, Stefania; Merighi, Stefania; Vincenzi, Fabrizio; Varani, Katia

   British Journal of Pharmacology (2017), 174 (13), 1945-1960CODEN: BJPCBM; ISSN:1476-5381. (Wiley-Blackwell)

   Adenosine is an endogenous ubiquitous purine nucleoside, which is increased by hypoxia, ischemia and tissue damage and mediates a no. of physiopathol. effects by interacting with four GPCRs, identified as A1, A2A, A2B and A3. Physiol. and acutely increased adenosine is mostly assocd. with beneficial effects that include vasodilatation and a decrease in inflammation. In contrast, chronic overprodn. of adenosine occurs in important pathol. states, where long-lasting increases in the nucleoside levels are responsible for the bad side of adenosine assocd. with chronic inflammation, fibrosis and organ damage. In this review, we describe and critically discuss the pathol. overprodn. of adenosine and analyze when, where and how adenosine exerts its detrimental effects throughout the body.
7. 7

   Chen, J. F.; Eltzschig, H. K.; Fredholm, B. B. Adenosine Receptors as Drug Targets-What Are the Challenges?. Nat. Rev. Drug Discovery 2013, 12 (4), 265– 286,  DOI: 10.1038/nrd3955

   Google Scholar

   7

   Adenosine receptors as drug targets - what are the challenges?

   Chen, Jiang-Fan; Eltzschig, Holger K.; Fredholm, Bertil B.

   Nature Reviews Drug Discovery (2013), 12 (4), 265-286CODEN: NRDDAG; ISSN:1474-1776. (Nature Publishing Group)

   A review. Adenosine signalling has long been a target for drug development, with adenosine itself or its derivs. being used clin. since the 1940s. In addn., methylxanthines such as caffeine have profound biol. effects as antagonists at adenosine receptors. Moreover, drugs such as dipyridamole and methotrexate act by enhancing the activation of adenosine receptors. There is strong evidence that adenosine has a functional role in many diseases, and several pharmacol. compds. specifically targeting individual adenosine receptors - either directly or indirectly - have now entered the clinic. However, only one adenosine receptor-specific agent - the adenosine A2A receptor agonist regadenoson (Lexiscan; Astellas Pharma) - has so far gained approval from the US Food and Drug Administration (FDA). Here, we focus on the biol. of adenosine signalling to identify hurdles in the development of addnl. pharmacol. compds. targeting adenosine receptors and discuss strategies to overcome these challenges.
8. 8

   Müller, C. E.; Jacobson, K. A. Recent Developments in Adenosine Receptor Ligands and Their Potential as Novel Drugs.. Biochim. Biophys. Acta - Biomembr. 2011, 1808 (5), 1290– 1308,  DOI: 10.1016/j.bbamem.2010.12.017

   Google Scholar

   8

   Recent developments in adenosine receptor ligands and their potential as novel drugs

   Mueller, Christa E.; Jacobson, Kenneth A.

   Biochimica et Biophysica Acta, Biomembranes (2011), 1808 (5), 1290-1308CODEN: BBBMBS; ISSN:0005-2736. (Elsevier B.V.)

   A review. Medicinal chem. approaches have been applied to all four of the adenosine receptor (AR) subtypes (A1, A2A, A2B, and A3) to create selective agonists and antagonists for each. The most recent class of selective AR ligands to be reported is the class of A2BAR agonists. The availability of these selective ligands has facilitated research on therapeutic applications of modulating the ARs and in some cases has provided clin. candidates. Prodrug approaches have been developed which improve the bioavailability of the drugs, reduce side-effects, and/or may lead to site-selective effects. The A2A agonist regadenoson (Lexiscan), a diagnostic drug for myocardial perfusion imaging, is the first selective AR agonist to be approved. Other selective agonists and antagonists are or were undergoing clin. trials for a broad range of indications, including capadenoson and tecadenoson (A1 agonists) for atrial fibrillation, or paroxysmal supraventricular tachycardia, resp., apadenoson and binodenoson (A2A agonists) for myocardial perfusion imaging, preladenant (A2A antagonist) for the treatment of Parkinson's disease, and CF101 and CF102 (A3 agonists) for inflammatory diseases and cancer, resp. This article is part of a Special Issue entitled: "Adenosine Receptors".
9. 9

   Zhou, Q. Y.; Li, C.; Olah, M. E.; Johnson, R. A.; Stiles, G. L.; Civelli, O. Molecular Cloning and Characterization of an Adenosine Receptor: The A3 Adenosine Receptor. Proc. Natl. Acad. Sci. U. S. A. 1992, 89 (16), 7432– 7436,  DOI: 10.1073/pnas.89.16.7432

   Google Scholar

   9

   Molecular cloning and characterization of an adenosine receptor: The A3 adenosine receptor

   Zhou, Qun Yong; Li, Chuanyu; Olah, Mark E.; Johnson, Robert A.; Stiles, Gary L.; Civelli, Olivier

   Proceedings of the National Academy of Sciences of the United States of America (1992), 89 (16), 7432-6CODEN: PNASA6; ISSN:0027-8424.

   The authors have previously reported the selective amplification of several rat striatal cDNA sequences that encode guanine nucleotide-binding regulatory protein (G protein)-coupled receptors. One of these sequences (R226) exhibited high sequence identity (58%) with the two previously cloned adenosine receptors. A full-length cDNA clone for R226 has been isolated from a rat brain cDNA library. The cDNA clone encodes a protein of 320 amino acids that can be organized into seven transmembrane stretches. R226 has been expressed in COS-7 and CHO cells and membranes from the transfected cells were screened with adenosine receptor radioligands. R226 could bind the nonselective adenosine agonist tritiated N-ethyladenosine 5'-uronic acid ([3H]NECA) and the A1-selective agonist radioiodinated N6-2-(4-amino-3-iodophenyl)-ethyladenosine ([125I]APNEA) but not the A1-selective antagonists tritiated 1,3-dipropyl-8-cyclopentylxanthine ([3H]DPCPX) or 8-{4-[({[(2-aminoethyl)amino]carbonyl}methyl)oxy]-phenyl}-1,3-dipropylxanthine ([3H]XAC) or the A2-selective agonist ligands tritiated 2-[4-(2-carboxyethyl)phenyl]ethylamino 5'-N-ethylcarboxamidoadenosine ([3H]CGS21680) or radioiodinated 2-[4-({2-[(4-aminophenyl)methylcarbonylamino]ethylaminocarbonyl}ethyl)phenyl]ethylamino 5'-N-ethylcarboxamidoadenosine. Extensive characterization with [125I]APNEA showed that R226 binds [125I]APNEA with high affinity (Kd = 15.5 nM) and the specific [125I]APNEA binding could be inhibited by adenosine ligands with a potency order of (R)-N6-phenyl-2-propyladenosine (R-PIA) = NECA > S-PIA > adenosine > ATP = ADP but not by antagonists XAC, isobutylmethylxanthine, and DPCPX. In R226 stably transfected CHO cells, adenosine agonists R-PIA, NECA, and CGS21680 inhibited by 40-50% the forskolin-stimulated cAMP accumulation through a pertussis toxin-sensitive G protein with an EC50 of 18 nM, 23 nM, and 144 nM, resp. Based on these observations the authors conclude that R226 encodes an adenosine receptor with non-A1 and non-A2 specificity, and name it the A3 adenosine receptor. The mRNA analyses revealed that the highest expression of R226 was in the testis and low-level mRNAs were also found in the lung, kidneys, heart, and some parts of the central nervous system such as cortex, striatum, and olfactory bulb. The high-expression level of the A3 receptor in the testis suggests a possible role for adenosine in reprodn.
10. 10

    Reiss, A. B.; Grossfeld, D.; Kasselman, L. J.; Renna, H. A.; Vernice, N. A.; Drewes, W.; Konig, J.; Carsons, S. E.; DeLeon, J. Adenosine and the Cardiovascular System. Am. J. Cardiovasc. Drugs 2019, 19 (5), 449– 464,  DOI: 10.1007/s40256-019-00345-5

    Google Scholar

    10

    Adenosine and the Cardiovascular System

    Reiss, Allison B.; Grossfeld, David; Kasselman, Lora J.; Renna, Heather A.; Vernice, Nicholas A.; Drewes, Wendy; Konig, Justin; Carsons, Steven E.; DeLeon, Joshua

    American Journal of Cardiovascular Drugs (2019), 19 (5), 449-464CODEN: AJCDDJ; ISSN:1175-3277. (Springer International Publishing AG)

    A review. Adenosine is an endogenous nucleoside with a short half-life that regulates many physiol. functions involving the heart and cardiovascular system. Among the cardioprotective properties of adenosine are its ability to improve cholesterol homeostasis, impact platelet aggregation and inhibit the inflammatory response. Through modulation of forward and reverse cholesterol transport pathways, adenosine can improve cholesterol balance and thereby protect macrophages from lipid overload and foam cell transformation. The function of adenosine is controlled through four G-protein coupled receptors: A1, A2A, A2B and A3. Of these four, it is the A2A receptor that is in a large part responsible for the anti-inflammatory effects of adenosine as well as defense against excess cholesterol accumulation. A2A receptor agonists are the focus of efforts by the pharmaceutical industry to develop new cardiovascular therapies, and pharmacol. actions of the atheroprotective and anti-inflammatory drug methotrexate are mediated via release of adenosine and activation of the A2A receptor. Also relevant are anti-platelet agents that decrease platelet activation and adhesion and reduce thrombotic occlusion of atherosclerotic arteries by antagonizing ADP-mediated effects on the P2Y12 receptor. The purpose of this review is to discuss the effects of adenosine on cell types found in the arterial wall that are involved in atherosclerosis, to describe use of adenosine and its receptor ligands to limit excess cholesterol accumulation and to explore clin. applied anti-platelet effects. Its impact on electrophysiol. and use as a clin. treatment for myocardial preservation during infarct will also be covered. Results of cell culture studies, animal expts. and human clin. trials are presented. Finally, we highlight future directions of research in the application of adenosine as an approach to improving outcomes in persons with cardiovascular disease.
11. 11

    Gessi, S.; Merighi, S.; Varani, K.; Leung, E.; Mac Lennan, S.; Borea, P. A. The A3 Adenosine Receptor: An Enigmatic Player in Cell Biology. Pharmacol. Ther. 2008, 117 (1), 123– 140,  DOI: 10.1016/j.pharmthera.2007.09.002

    Google Scholar

    11

    The A3 adenosine receptor: An enigmatic player in cell biology

    Gessi, Stefania; Merighi, Stefania; Varani, Katia; Leung, Edward; Mac Lennan, Stephen; Borea, Pier Andrea

    Pharmacology & Therapeutics (2008), 117 (1), 123-140CODEN: PHTHDT; ISSN:0163-7258. (Elsevier B.V.)

    A review. Adenosine is a primordial signaling mol. present in every cell of the human body that mediates its physiol. functions by interacting with 4 subtypes of G-protein-coupled receptors, termed A1, A2A, A2B and A3. The A3 subtype is perhaps the most enigmatic among adenosine receptors since, although several studies have been performed in the years to elucidate its physiol. function, it still presents in several cases a double nature in different pathophysiol. conditions. The 2 personalities of A3 often come into direct conflict, e.g., in ischemia, inflammation and cancer, rendering this receptor as a single entity behaving in 2 different ways. This review focuses on the most relevant aspects of A3 adenosine subtype activation and summarizes the pharmacol. evidence as the basis of the dichotomy of this receptor in different therapeutic fields. Although much is still to be learned about the function of the A3 receptor and in spite of its duality, at the present time it can be speculated that A3 receptor selective ligands might show utility in the treatment of ischemic conditions, glaucoma, asthma, arthritis, cancer and other disorders in which inflammation is a feature. The biggest and most intriguing challenge for the future is therefore to understand whether and where selective A3 agonists or antagonists are the best choice.
12. 12

    Jacobson, K. A.; Klutz, A. M.; Tosh, D. K.; Ivanov, A. A.; Preti, D.; Baraldi, P. G. Medicinal Chemistry of the A3 Adenosine Receptor: Agonists, Antagonists, and Receptor Engineering. Handb. Exp. Pharmacol. 2009, 193, 123– 159,  DOI: 10.1007/978-3-540-89615-9_5

    Google Scholar

    12

    Medicinal chemistry of the A3 adenosine receptor: agonists, antagonists, and receptor engineering

    Jacobson, Kenneth A.; Klutz, Athena M.; Tosh, Dilip K.; Ivanov, Andrei A.; Preti, Delia; Baraldi, Pier Giovanni

    Handbook of Experimental Pharmacology (2009), 193 (Adenosine Receptors in Health and Disease), 123-159CODEN: HEPHD2; ISSN:0171-2004. (Springer GmbH)

    A review. A3 adenosine receptor (A3AR) ligands have been modified to optimize their interaction with the A3AR. Most of these modifications have been made to the N6 and C2 positions of adenine as well as the ribose moiety, and using a combination of these substitutions leads to the most efficacious, selective, and potent ligands. A3AR agonists such as IB-MECA and Cl-IB-MECA are now advancing into Phase II clin. trials for treatments targeting diseases such as cancer, arthritis, and psoriasis. Also, a wide no. of compds. exerting high potency and selectivity in antagonizing the human (h)A3AR have been discovered. These mols. are generally characterized by a notable structural diversity, taking into account that arom. nitrogen-contg. monocyclic (thiazoles and thiadiazoles), bicyclic (isoquinoline, quinozalines, (aza)adenines), tricyclic systems (pyrazoloquinolines, triazoloquinoxalines, pyrazolotriazolopyrimidines, triazolopurines, tricyclic xanthines) and nucleoside derivs. have been identified as potent and selective A3AR antagonists. Probably due to the "enigmatic" physiol. role of A3AR, whose activation may produce opposite effects (for example, concerning tissue protection in inflammatory and cancer cells) and may produce effects that are species dependent, only a few mols. have reached preclin. investigation. Indeed, the most advanced A3AR antagonists remain in preclin. testing. Among the antagonists described above, compd. OT-7999 is expected to enter clin. trials for the treatment of glaucoma, while several thiazole derivs. are in development as antiallergic, antiasthmatic and/or antiinflammatory drugs.
13. 13

    Jacobson, K. A.; Tosh, D. K.; Jain, S.; Gao, Z. G. Historical and Current Adenosine Receptor Agonists in Preclinical and Clinical Development. Front. Cell. Neurosci. 2019, 13 (March), 1– 17,  DOI: 10.3389/fncel.2019.00124

    Google Scholar

    There is no corresponding record for this reference.
14. 14

    Vecchio, E. A.; Baltos, J. A.; Nguyen, A. T. N.; Christopoulos, A.; White, P. J.; May, L. T. New Paradigms in Adenosine Receptor Pharmacology: Allostery, Oligomerization and Biased Agonism. Br. J. Pharmacol. 2018, 175 (21), 4036– 4046,  DOI: 10.1111/bph.14337

    Google Scholar

    14

    New paradigms in adenosine receptor pharmacology: allostery, oligomerization and biased agonism

    Vecchio, Elizabeth A.; Baltos, Jo-Anne; Nguyen, Anh T. N.; Christopoulos, Arthur; White, Paul J.; May, Lauren T.

    British Journal of Pharmacology (2018), 175 (21), 4036-4046CODEN: BJPCBM; ISSN:1476-5381. (Wiley-Blackwell)

    A review. Adenosine receptors are a family of GPCRs contg. four subtypes (A1, A2A, A2B and A3 receptors), all of which bind the ubiquitous nucleoside adenosine. These receptors play an important role in physiol. and pathophysiol. and therefore represent attractive drug targets for a range of conditions. The theor. framework surrounding drug action at adenosine receptors now extends beyond the notion of prototypical agonism and antagonism to encompass more complex pharmacol. concepts. New paradigms include allostery, in which ligands bind a topog. distinct receptor site from that of the endogenous agonist, homomeric or heteromeric interactions across receptor oligomers and biased agonism, i.e., ligand-dependent differential intracellular signaling. This review provides a concise overview of allostery, oligomerization and biased agonism at adenosine receptors and outlines how these paradigms may enhance future drug discovery endeavours focussed on the development of novel therapeutic agents acting at adenosine receptors.
15. 15

    Pipeline; Palobiofarma. https://www.palobiofarma.com/pipeline-2/.

    Google Scholar

    There is no corresponding record for this reference.
16. 16

    Park, C. W.; Han, C. T.; Sakaguchi, Y.; Lee, J.; Youn, H. Y. Safety Evaluation of Fm101, an A3 Adenosine Receptor Modulator, in Rat, for Developing as Therapeutics of Glaucoma and Hepatitis. EXCLI J. 2020, 19, 187– 200,  DOI: 10.17179/excli2019-2058

    Google Scholar

    16

    Safety evaluation of FM101, an A3 adenosine receptor modulator, in rat, for developing as therapeutics of glaucoma and hepatitis

    Park Chong-Woo; Lee Jiyoun; Park Chong-Woo; Youn Hwa-Young; Han Chung-Tack; Sakaguchi Yasue

    EXCLI journal (2020), 19 (), 187-200 ISSN:1611-2156.

    Adenosine is a critical regulator of inflammation and fibrosis, it affects endogenous cell signaling via binding to the A3 adenosine receptor. FM101 is a potent, highly selective A3 adenosine receptor modulator that has been developed as a treatment for glaucoma and hepatitis. We determined that FM101 is a biased ligand with functional activities both as a G protein agonist and a β-arrestin antagonist. The safety of FM101 was evaluated by administering an acute dose in rats, the results indicated that the approximate lethal dose was greater than 2000 mg/kg. In a subchronic toxicity study, FM101 was administered orally once per day to rats at doses of 250, 500, and 1000 mg/kg/day over a period of 28 days. Abnormal posture, irregular respiration, decreased movement, and ear flushing were observed during the early phase of dosing, and loose stools were observed sporadically among the animals that received 500 and 1000 mg/kg/day. Body weight and food consumption were decreased in one male and one female rat in the 1000 mg/kg/day group during the first 2 weeks of observation. However, there were no test substance-related changes or adverse effects observed during our ophthalmological, clinical chemistry, urine, organ weight, and histopathological analysis. These findings indicate that no observed adverse effect level of FM101 was 1000 mg/kg/day in male and female rats.
17. 17

    A SAD, MAD, and FE Study to Evaluate the Safety, Tolerability, and Pharmacokinetic Profile of FM101 in Healthy Volunteers. ClinicalTrials.gov. https://clinicaltrials.gov/ct2/show/NCT03879928.

    Google Scholar

    There is no corresponding record for this reference.
18. 18

    Yaziji, V.; Rodríguez, D.; Gutiérrez-De-Terán, H.; Coelho, A.; Caamaño, O.; García-Mera, X.; Brea, J.; Loza, M. I.; Cadavid, M. I.; Sotelo, E. Pyrimidine Derivatives as Potent and Selective A3 Adenosine Receptor Antagonists. J. Med. Chem. 2011, 54 (2), 457– 471,  DOI: 10.1021/jm100843z

    Google Scholar

    18

    Pyrimidine derivatives as potent and selective A3 adenosine receptor antagonists

    Yaziji, Vicente; Rodriguez, David; Gutierrez-de-Teran, Hugo; Coelho, Alberto; Caamano, Olga; Garcia-Mera, Xerardo; Brea, Jose; Loza, Maria Isabel; Cadavid, Maria Isabel; Sotelo, Eddy

    Journal of Medicinal Chemistry (2011), 54 (2), 457-471CODEN: JMCMAR; ISSN:0022-2623. (American Chemical Society)

    Two regioisomeric series of diaryl 2- or 4-amidopyrimidines e. g. I, II have been synthesized and their adenosine receptor affinities were detd. in radioligand binding assays at the four human adenosine receptors (hARs). Some of the ligands prepd. herein exhibit remarkable affinities (Ki < 10 nm) and, most noticeably, the absence of activity at the A1, A2A, and A2B receptors. The structural determinants that support the affinity and selectivity profiles of the series were highlighted through an integrated computational approach, combining a 3D-QSAR model built on the second generation of GRid Independent Descriptors (GRIND2) with a novel homol. model of the hA3 receptor. The robustness of the computational model was subsequently evaluated by the design of new derivs. exploring the alkyl substituent of the exocyclic amide group. The synthesis and evaluation of the novel compds. validated the predictive power of the model, exhibiting excellent agreement between predicted and exptl. activities.
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    Yaziji, V.; Rodríguez, D.; Coelho, A.; García-Mera, X.; El Maatougui, A.; Brea, J.; Loza, M. I.; Cadavid, M. I.; Gutiérrez-De-Terán, H.; Sotelo, E. Selective and Potent Adenosine A3 Receptor Antagonists by Methoxyaryl Substitution on the N-(2,6-Diarylpyrimidin-4-Yl)Acetamide Scaffold. Eur. J. Med. Chem. 2013, 59, 235– 242,  DOI: 10.1016/j.ejmech.2012.11.010

    Google Scholar

    19

    Selective and potent adenosine A3 receptor antagonists by methoxyaryl substitution on the N-(2,6-diarylpyrimidin-4-yl)acetamide scaffold

    Yaziji, Vicente; Rodriguez, David; Coelho, Alberto; Garcia-Mera, Xerardo; El Maatougui, Abdelaziz; Brea, Jose; Loza, Maria Isabel; Cadavid, Maria Isabel; Gutierrez-de-Teran, Hugo; Sotelo, Eddy

    European Journal of Medicinal Chemistry (2013), 59 (), 235-242CODEN: EJMCA5; ISSN:0223-5234. (Elsevier Masson SAS)

    The influence of diverse methoxyphenyl substitution patterns on the N-(2,6-diarylpyrimidin-4-yl)acetamide scaffold is herein explored in order to modulate the A3 adenosine receptor antagonistic profile. As a result, novel ligands exhibiting excellent potency (Ki on A3 AR < 20 nM) and selectivity profiles (above 100-fold within the adenosine receptors family) are reported. Moreover, our joint theor. and exptl. approach allows the identification of novel pharmacophoric elements conferring A3AR selectivity, first established by a robust computational model and thereafter characterizing the most salient features of the structure-activity and structure-selectivity relationships in this series.
20. 20

    Azuaje, J.; Jespers, W.; Yaziji, V.; Mallo, A.; Majellaro, M.; Caamaño, O.; Loza, M. I.; Cadavid, M. I.; Brea, J.; Åqvist, J.; Sotelo, E.; Gutiérrez-De-Terán, H. Effect of Nitrogen Atom Substitution in A3 Adenosine Receptor Binding: N-(4,6-Diarylpyridin-2-Yl)Acetamides as Potent and Selective Antagonists. J. Med. Chem. 2017, 60 (17), 7502– 7511,  DOI: 10.1021/acs.jmedchem.7b00860

    Google Scholar

    20

    Effect of Nitrogen Atom Substitution in A3 Adenosine Receptor Binding: N-(4,6-Diarylpyridin-2-yl)acetamides as Potent and Selective Antagonists

    Azuaje, Jhonny; Jespers, Willem; Yaziji, Vicente; Mallo, Ana; Majellaro, Maria; Caamano, Olga; Loza, Maria I.; Cadavid, Maria I.; Brea, Jose; Aqvist, Johan; Sotelo, Eddy; Gutierrez-de-Teran, Hugo

    Journal of Medicinal Chemistry (2017), 60 (17), 7502-7511CODEN: JMCMAR; ISSN:0022-2623. (American Chemical Society)

    The authors 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 chem. scaffold to the parent series of diarylpyrimidines. In addn., using mol. dynamics and free energy perturbation simulations, the authors 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 chem. simple, potent, and selective antagonists for the hA3AR, and exemplifies the benefits of a joint theor.-exptl. approach to identify novel hA3AR antagonists through succinct and efficient synthetic methodologies.
21. 21

    RDKit.

    Google Scholar

    There is no corresponding record for this reference.
22. 22

    Schrödinger Suite, 2012 ed.; Schrödinger, LLC, 2012.

    Google Scholar

    There is no corresponding record for this reference.
23. 23

    Esguerra, M.; Siretskiy, A.; Bello, X.; Sallander, J.; Gutiérrez-de-Terán, H. GPCR-ModSim: A Comprehensive Web Based Solution for Modeling G-Protein Coupled Receptors. Nucleic Acids Res. 2016, 44 (W1), W455– W462,  DOI: 10.1093/nar/gkw403

    Google Scholar

    23

    GPCR-ModSim: a comprehensive web based solution for modeling G-protein coupled receptors

    Esguerra, Mauricio; Siretskiy, Alexey; Bello, Xabier; Sallander, Jessica; Gutierrez-de-Teran, Hugo

    Nucleic Acids Research (2016), 44 (W1), W455-W462CODEN: NARHAD; ISSN:0305-1048. (Oxford University Press)

    GPCR-ModSim is a centralized and easy to use service dedicated to the structural modeling of G-protein Coupled Receptors (GPCRs). 3D mol. models can be generated from amino acid sequence by homol.-modeling techniques, considering different receptor conformations. GPCR-ModSim includes a membrane insertion and mol. dynamics (MD) equilibration protocol, which can be used to refine the generated model or any GPCR structure uploaded to the server, including if desired non-protein elements such as orthosteric or allosteric ligands, structural waters or ions. We herein revise the main characteristics of GPCR-ModSim and present new functionalities. The templates used for homol. modeling have been updated considering the latest structural data, with sep. profile structural alignments built for inactive, partially-active and active groups of templates. We have also added the possibility to perform multiple-template homol. modeling in a unique and flexible way. Finally, our new MD protocol considers a series of distance restraints derived from a recently identified conserved network of helical contacts, allowing for a smoother refinement of the generated models which is particularly advised when there is low homol. to the available templates. GPCR-ModSim has been tested on the GPCR Dock 2013 competition with satisfactory results.
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    Hess, B.; Kutzner, C.; Van Der Spoel, D.; Lindahl, E. GRGMACS 4: Algorithms for Highly Efficient, Load-Balanced, and Scalable Molecular Simulation. J. Chem. Theory Comput. 2008, 4 (3), 435– 447,  DOI: 10.1021/ct700301q

    Google Scholar

    24

    GROMACS 4: Algorithms for Highly Efficient, Load-Balanced, and Scalable Molecular Simulation

    Hess, Berk; Kutzner, Carsten; van der Spoel, David; Lindahl, Erik

    Journal of Chemical Theory and Computation (2008), 4 (3), 435-447CODEN: JCTCCE; ISSN:1549-9618. (American Chemical Society)

    Mol. simulation is an extremely useful, but computationally very expensive tool for studies of chem. and biomol. systems. Here, we present a new implementation of our mol. simulation toolkit GROMACS which now both achieves extremely high performance on single processors from algorithmic optimizations and hand-coded routines and simultaneously scales very well on parallel machines. The code encompasses a minimal-communication domain decompn. algorithm, full dynamic load balancing, a state-of-the-art parallel constraint solver, and efficient virtual site algorithms that allow removal of hydrogen atom degrees of freedom to enable integration time steps up to 5 fs for atomistic simulations also in parallel. To improve the scaling properties of the common particle mesh Ewald electrostatics algorithms, we have in addn. used a Multiple-Program, Multiple-Data approach, with sep. node domains responsible for direct and reciprocal space interactions. Not only does this combination of algorithms enable extremely long simulations of large systems but also it provides that simulation performance on quite modest nos. of std. cluster nodes.