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Tan A, Babak MV, Venkatesan G, Lim C, Klotz KN, Herr DR, Cheong SL, Federico S, Spalluto G, Ong WY, Chen YZ, Loo JSE, Pastorin G. Design, Synthesis and Evaluation of New Indolylpyrimidylpiperazines for Gastrointestinal Cancer Therapy. Molecules 2019; 24:E3661. [PMID: 31614517 PMCID: PMC6832257 DOI: 10.3390/molecules24203661] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2019] [Revised: 10/04/2019] [Accepted: 10/08/2019] [Indexed: 11/29/2022] Open
Abstract
Human A3 adenosine receptor hA3AR has been implicated in gastrointestinal cancer, where its cellular expression has been found increased, thus suggesting its potential as a molecular target for novel anticancer compounds. Observation made in our previous work indicated the importance of the carbonyl group of amide in the indolylpyrimidylpiperazine (IPP) for its human A2A adenosine receptor (hA2AAR) subtype binding selectivity over the other AR subtypes. Taking this observation into account, we structurally modified an indolylpyrimidylpiperazine (IPP) scaffold, 1 (a non-selective adenosine receptors' ligand) into a modified IPP (mIPP) scaffold by switching the position of the carbonyl group, resulting in the formation of both ketone and tertiary amine groups in the new scaffold. Results showed that such modification diminished the A2A activity and instead conferred hA3AR agonistic activity. Among the new mIPP derivatives (3-6), compound 4 showed potential as a hA3AR partial agonist, with an Emax of 30% and EC50 of 2.89 ± 0.55 μM. In the cytotoxicity assays, compound 4 also exhibited higher cytotoxicity against both colorectal and liver cancer cells as compared to normal cells. Overall, this new series of compounds provide a promising starting point for further development of potent and selective hA3AR partial agonists for the treatment of gastrointestinal cancers.
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Affiliation(s)
- Aaron Tan
- NUS Graduate School of Integrative Sciences and Engineering, National University of Singapore, Centre for Life Sciences, #05-01, 28 Medical Drive, Singapore 117456, Singapore.
| | - Maria V Babak
- Department of Pharmacy, National University of Singapore, Singapore 119260, Singapore.
| | | | - Clarissa Lim
- Department of Pharmacy, National University of Singapore, Singapore 119260, Singapore.
| | - Karl-Norbert Klotz
- Institut für Pharmakologie und Toxikologie, Universität Würzburg, 97078 Würzburg, Germany.
| | - Deron Raymond Herr
- Department of Pharmacology, National University of Singapore, Singapore 117600, Singapore.
| | - Siew Lee Cheong
- Department of Pharmaceutical Chemistry, School of Pharmacy, International Medical University, 126 Jalan Jalil Perkasa 19, Bukit Jalil, Kuala Lumpur 57000, Malaysia.
| | - Stephanie Federico
- Dipartimento di Scienze Chimiche e Farmaceutiche, Università degli Studi di Trieste, 34127 Trieste, Italy.
| | - Giampiero Spalluto
- Dipartimento di Scienze Chimiche e Farmaceutiche, Università degli Studi di Trieste, 34127 Trieste, Italy.
| | - Wei-Yi Ong
- Department of Anatomy, National University of Singapore, Singapore 119260, Singapore.
| | - Yu Zong Chen
- Department of Pharmacy, National University of Singapore, Singapore 119260, Singapore.
| | - Jason Siau Ee Loo
- School of Pharmacy, Faculty of Health and Medical Sciences, Taylor's University, 1, Jalan Taylors, Subang Jaya, Selangor 47500, Malaysia.
| | - Giorgia Pastorin
- NUS Graduate School of Integrative Sciences and Engineering, National University of Singapore, Centre for Life Sciences, #05-01, 28 Medical Drive, Singapore 117456, Singapore.
- Department of Pharmacy, National University of Singapore, Singapore 119260, Singapore.
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Affiliation(s)
- Daniel P Walsh
- Department of Chemistry, New York University, New York, New York 10003, USA
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Tchilibon S, Joshi BV, Kim SK, Duong HT, Gao ZG, Jacobson KA. (N)-methanocarba 2,N6-disubstituted adenine nucleosides as highly potent and selective A3 adenosine receptor agonists. J Med Chem 2005; 48:1745-58. [PMID: 15771421 PMCID: PMC3463111 DOI: 10.1021/jm049580r] [Citation(s) in RCA: 84] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
A series of ring-constrained (N)-methanocarba-5'-uronamide 2,N(6)-disubstituted adenine nucleosides have been synthesized via Mitsunobu condensation of the nucleobase precursor with a pseudosugar ring containing a 5'-ester functionality. Following appropriate functionalization of the adenine ring, the ester group was converted to the 5'-N-methylamide. The compounds, mainly 2-chloro-substituted derivatives, were tested in both binding and functional assays at human adenosine receptors (ARs), and many were found to be highly potent and selective A(3)AR agonists. Selected compounds were compared in binding to the rat A(3)AR to assess their viability for testing in rat disease models. The N(6)-(3-chlorobenzyl) and N(6)-(3-bromobenzyl) analogues displayed K(i) values at the human A(3)AR of 0.29 and 0.38 nM, respectively. Other subnanomolar affinities were observed for the following N(6) derivatives: 2,5-dichlorobenzyl, 5-iodo-2-methoxybenzyl, trans-2-phenyl-1-cyclopropyl, and 2,2-diphenylethyl. Selectivity for the human A(3)AR in comparison to the A(1)AR was the following (fold): the N(6)-(2,2-diphenylethyl) analogue 34 (1900), the N(6)-(2,5-dimethoxybenzyl) analogue 26 (1200), the N(6)-(2,5-dichlorobenzyl) and N(6)-(2-phenyl-1-cyclopropyl) analogues 20 and 33 (1000), and the N(6)-(3-substituted benzyl) analogues 17, 18, 28, and 29 (700-900). Typically, even greater selectivity ratios were obtained in comparison with the A(2A) and A(2B)ARs. The (N)-methanocarba-5'-uronamide analogues were full agonists at the A(3)AR, as indicated by the inhibition of forskolin-stimluated adenylate cyclase at a concentration of 10 microM. The N(6)-(2,2-diphenylethyl) derivative was an A(3)AR agonist in the (N)-methanocarba-5'-uronamide series, although it was an antagonist in the ribose series. Thus, many of the previously known groups that enhance A(3)AR affinity in the 9-riboside series, including those that reduce intrinsic efficacy, may be adapted to the (N)-methanocarba nucleoside series of full agonists.
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Affiliation(s)
- Susanna Tchilibon
- Molecular Recognition Section, Laboratory of Bioorganic Chemistry, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Bhalchandra V. Joshi
- Molecular Recognition Section, Laboratory of Bioorganic Chemistry, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Soo-Kyung Kim
- Molecular Recognition Section, Laboratory of Bioorganic Chemistry, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Heng T. Duong
- Molecular Recognition Section, Laboratory of Bioorganic Chemistry, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Zhan-Guo Gao
- Molecular Recognition Section, Laboratory of Bioorganic Chemistry, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Kenneth A. Jacobson
- Molecular Recognition Section, Laboratory of Bioorganic Chemistry, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892, USA
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Yan L, Burbiel JC, Maass A, Müller CE. Adenosine receptor agonists: from basic medicinal chemistry to clinical development. Expert Opin Emerg Drugs 2005; 8:537-76. [PMID: 14662005 DOI: 10.1517/14728214.8.2.537] [Citation(s) in RCA: 104] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Adenosine is a physiological nucleoside which acts as an autocoid and activates G protein-coupled membrane receptors, designated A(1), A(2A), A(2B) and A(3). Adenosine plays an important role in many (patho)physiological conditions in the CNS as well as in peripheral organs and tissues. Adenosine receptors are present on virtually every cell. However, receptor subtype distribution and densities vary greatly. Adenosine itself is used as a therapeutic agent for the treatment of supraventricular paroxysmal tachycardia and arrhythmias and as a vasodilatatory agent in cardiac imaging. During the past 20 years, a number of selective agonists for A(1), A(2A) and A(3) adenosine receptors have been developed, all of them structurally derived from adenosine. Several such compounds are currently undergoing clinical trials for the treatment of cardiovascular diseases (A(1)and A(2A)), pain (A(1)), wound healing (A(2A)), diabetic foot ulcers (A(2A)), colorectal cancer (A(3)) and rheumatoid arthritis (A(3)). Clinical evaluation of some A(1) and A(2A) adenosine receptor agonists has been discontinued. Major problems include side effects due to the wide distribution of adenosine receptors; low brain penetration, which is important for the targeting of CNS diseases; short half-lifes of compounds; or a lack of effects, in some cases perhaps due to receptor desensitisation or to low receptor density in the targeted tissue. Partial agonists, inhibitors of adenosine metabolism (adenosine kinase and deaminase inhibitors) or allosteric activators of adenosine receptors may be advantageous for certain indications, as they may exhibit fewer side effects.
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Affiliation(s)
- Luo Yan
- University of Bonn, Pharmaceutical Institute Poppelsdorf, Kreuzbergweg 26, D-53115 Bonn, Germany
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Van Rompaey P, Jacobson KA, Gross AS, Gao ZG, Van Calenbergh S. Exploring human adenosine A3 receptor complementarity and activity for adenosine analogues modified in the ribose and purine moiety. Bioorg Med Chem 2005; 13:973-83. [PMID: 15670905 PMCID: PMC3460517 DOI: 10.1016/j.bmc.2004.11.044] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2004] [Revised: 11/18/2004] [Accepted: 11/23/2004] [Indexed: 11/17/2022]
Abstract
In this paper we investigated the influence on affinity, selectivity and intrinsic activity upon modification of the adenosine agonist scaffold at the 3'- and 5'-positions of the ribofuranosyl moiety and the 2- and N6-positions of the purine base. This resulted in the synthesis of various analogues, that is, 3-12 and 24-33, with good hA3AR selectivity and moderate-to-high affinities (as in 32, Ki=27 nM). Interesting was the ability to tune the intrinsic activity depending on the substituent introduced at the 3'-position.
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Affiliation(s)
- Philippe Van Rompaey
- Laboratory for Medicinal Chemistry, Faculty of Pharmaceutical Sciences (FFW), Ghent University, Harelbekestraat 72, B-9000 Gent, Belgium
| | - Kenneth A. Jacobson
- Molecular Recognition Section, Laboratory of Bioorganic Chemistry, National Institute of Diabetes and Digestive and Kidney Disease (NIDDK), National Institutes of Health (NIH), Bethesda, MD 20892-0810, USA
| | - Ariel S. Gross
- Molecular Recognition Section, Laboratory of Bioorganic Chemistry, National Institute of Diabetes and Digestive and Kidney Disease (NIDDK), National Institutes of Health (NIH), Bethesda, MD 20892-0810, USA
| | - Zhan-Guo Gao
- Molecular Recognition Section, Laboratory of Bioorganic Chemistry, National Institute of Diabetes and Digestive and Kidney Disease (NIDDK), National Institutes of Health (NIH), Bethesda, MD 20892-0810, USA
| | - Serge Van Calenbergh
- Laboratory for Medicinal Chemistry, Faculty of Pharmaceutical Sciences (FFW), Ghent University, Harelbekestraat 72, B-9000 Gent, Belgium
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Tchilibon S, Kim SK, Gao ZG, Harris BA, Blaustein JB, Gross AS, Duong HT, Melman N, Jacobson KA. Exploring distal regions of the A3 adenosine receptor binding site: sterically constrained N6-(2-phenylethyl)adenosine derivatives as potent ligands. Bioorg Med Chem 2004; 12:2021-34. [PMID: 15080906 PMCID: PMC4667970 DOI: 10.1016/j.bmc.2004.02.037] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2003] [Revised: 02/11/2004] [Accepted: 02/28/2004] [Indexed: 10/26/2022]
Abstract
We synthesized phenyl ring-substituted analogues of N(6)-(1S,2R)-(2-phenyl-1-cyclopropyl)adenosine, which is highly potent in binding to the human A(3)AR with a Ki value of 0.63 nM. The effects of these structural changes on affinity at human and rat adenosine receptors and on intrinsic efficacy at the hA(3)AR were measured. A 3-nitrophenyl analogue was resolved chromatographically into pure diastereomers, which displayed 10-fold stereoselectivity in A(3)AR binding in favor of the 1S,2R isomer. A molecular model defined a hydrophobic region (Phe168) in the putative A(3)AR binding site around the phenyl moiety. A heteroaromatic group (3-thienyl) could substitute for the phenyl moiety with retention of high affinity of A(3)AR binding. Other related N(6)-substituted adenosine derivatives were included for comparison. Although the N(6)-(2-phenyl-1-cyclopropyl) derivatives were full A(3)AR agonists, several other derivatives had greatly reduced efficacy. N(6)-Cyclopropyladenosine was an A(3)AR antagonist, and adding either one or two phenyl rings at the 2-position of the cyclopropyl moiety restored efficacy. N(6)-(2,2-Diphenylethyl)adenosine was an A(3)AR antagonist, and either adding a bond between the two phenyl rings (N(6)-9-fluorenylmethyl) or shortening the ethyl moiety (N(6)-diphenylmethyl) restored efficacy. A QSAR study of the N(6) region provided a model that was complementary to the putative A(3)AR binding site in a rhodopsin-based homology model. Thus, a new series of high-affinity A(3)AR agonists and related nucleoside antagonists was explored through both empirical and theoretical approaches.
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Affiliation(s)
- Susanna Tchilibon
- Molecular Recognition Section, Laboratory of Bioorganic Chemistry, National Institute of Diabetes & Digestive & Kidney Diseases, National Institutes of Health (NIH), DHHS, Bethesda, MD 20892-0810, USA
| | - Soo-Kyung Kim
- Molecular Recognition Section, Laboratory of Bioorganic Chemistry, National Institute of Diabetes & Digestive & Kidney Diseases, National Institutes of Health (NIH), DHHS, Bethesda, MD 20892-0810, USA
| | - Zhan-Guo Gao
- Molecular Recognition Section, Laboratory of Bioorganic Chemistry, National Institute of Diabetes & Digestive & Kidney Diseases, National Institutes of Health (NIH), DHHS, Bethesda, MD 20892-0810, USA
| | - Brian A. Harris
- Molecular Recognition Section, Laboratory of Bioorganic Chemistry, National Institute of Diabetes & Digestive & Kidney Diseases, National Institutes of Health (NIH), DHHS, Bethesda, MD 20892-0810, USA
| | - Joshua B. Blaustein
- Molecular Recognition Section, Laboratory of Bioorganic Chemistry, National Institute of Diabetes & Digestive & Kidney Diseases, National Institutes of Health (NIH), DHHS, Bethesda, MD 20892-0810, USA
| | - Ariel S. Gross
- Molecular Recognition Section, Laboratory of Bioorganic Chemistry, National Institute of Diabetes & Digestive & Kidney Diseases, National Institutes of Health (NIH), DHHS, Bethesda, MD 20892-0810, USA
| | - Heng T. Duong
- Molecular Recognition Section, Laboratory of Bioorganic Chemistry, National Institute of Diabetes & Digestive & Kidney Diseases, National Institutes of Health (NIH), DHHS, Bethesda, MD 20892-0810, USA
| | - Neli Melman
- Molecular Recognition Section, Laboratory of Bioorganic Chemistry, National Institute of Diabetes & Digestive & Kidney Diseases, National Institutes of Health (NIH), DHHS, Bethesda, MD 20892-0810, USA
| | - Kenneth A. Jacobson
- Molecular Recognition Section, Laboratory of Bioorganic Chemistry, National Institute of Diabetes & Digestive & Kidney Diseases, National Institutes of Health (NIH), DHHS, Bethesda, MD 20892-0810, USA
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