TY - JOUR
T1 - "Reversine" and its 2-substituted adenine derivatives as potent and selective A3 adenosine receptor antagonists
AU - Perreira, Melissa
AU - Jiang, Jian Kang
AU - Klutz, Athena M.
AU - Gao, Zhan Guo
AU - Shainberg, Asher
AU - Lu, Changrui
AU - Thomas, Craig J.
AU - Jacobson, Kenneth A.
PY - 2005/7/28
Y1 - 2005/7/28
N2 - The dedifferentiation agent "reversine" [2-(4-morpholinoanilino)- N6-cyclohexyladenine 2] was found to be a moderately potent antagonist for the human A3 adenosine receptor (AR) with a K i value of 0.66 μM. This result prompted an exploration of the structure-activity relationship of related derivatives, synthesized via sequential substitution of 6-chloro-2-fluoropurine with selected nucleophiles. Optimization of substituents at these two positions identified 2-(phenyl-amino)-N6-cyclohexyladenine (12), 2-(phenylamino)-N 6-cycloheptyladenine (19), and 2-phenyl-amino-N6-endo- norbornyladenine (21) as potent AS AR ligands with Ki values of 51, 42, and 37 nM, respectively, with 30-200-fold selectivity in comparison to A1 and A2A ARs. The most selective A3 AR antagonist (>200-fold) was 2-(phenyloxy)-N6-cyclohexyladenine (22). 9-Methylation of 12, but not 19, was well-tolerated in A3 AR binding. Extension of the 2-phenylamino group to 2-benzyl- and 2-(2-phenylethylamino) reduced affinity. In the series of 2-(phenylamino), 2-(phenyloxy), and 2-(phenylthio) substitutions, the order of affinity at the A3 AR was oxy ≥ amino > thio. Selected derivatives, including reversine (KB value of 466 nM via Schild analysis), competitively antagonized the functional effects of a selective A3 AR agonist, i.e., inhibition of forskolin-stimulated cAMP production in stably transfected Chinese hamster ovary (CHO) cells. These results are in agreement with other studies suggesting the presence of a lipophilic pocket in the AR binding site that is filled by moderately sized cycloalkyl rings at the N6 position of both adenine and adenosine derivatives. Thus, the compound series reported herein comprise an important new series of selective A3 AR antagonists. We were unable to reproduce the dedifferentiation effect of reversine, previously reported, or to demonstrate any connection between A 3 AR antagonist effects and dedifferentiation.
AB - The dedifferentiation agent "reversine" [2-(4-morpholinoanilino)- N6-cyclohexyladenine 2] was found to be a moderately potent antagonist for the human A3 adenosine receptor (AR) with a K i value of 0.66 μM. This result prompted an exploration of the structure-activity relationship of related derivatives, synthesized via sequential substitution of 6-chloro-2-fluoropurine with selected nucleophiles. Optimization of substituents at these two positions identified 2-(phenyl-amino)-N6-cyclohexyladenine (12), 2-(phenylamino)-N 6-cycloheptyladenine (19), and 2-phenyl-amino-N6-endo- norbornyladenine (21) as potent AS AR ligands with Ki values of 51, 42, and 37 nM, respectively, with 30-200-fold selectivity in comparison to A1 and A2A ARs. The most selective A3 AR antagonist (>200-fold) was 2-(phenyloxy)-N6-cyclohexyladenine (22). 9-Methylation of 12, but not 19, was well-tolerated in A3 AR binding. Extension of the 2-phenylamino group to 2-benzyl- and 2-(2-phenylethylamino) reduced affinity. In the series of 2-(phenylamino), 2-(phenyloxy), and 2-(phenylthio) substitutions, the order of affinity at the A3 AR was oxy ≥ amino > thio. Selected derivatives, including reversine (KB value of 466 nM via Schild analysis), competitively antagonized the functional effects of a selective A3 AR agonist, i.e., inhibition of forskolin-stimulated cAMP production in stably transfected Chinese hamster ovary (CHO) cells. These results are in agreement with other studies suggesting the presence of a lipophilic pocket in the AR binding site that is filled by moderately sized cycloalkyl rings at the N6 position of both adenine and adenosine derivatives. Thus, the compound series reported herein comprise an important new series of selective A3 AR antagonists. We were unable to reproduce the dedifferentiation effect of reversine, previously reported, or to demonstrate any connection between A 3 AR antagonist effects and dedifferentiation.
UR - https://www.scopus.com/pages/publications/22744459205
U2 - 10.1021/jm050221l
DO - 10.1021/jm050221l
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C2 - 16033270
AN - SCOPUS:22744459205
SN - 0022-2623
VL - 48
SP - 4910
EP - 4918
JO - Journal of Medicinal Chemistry
JF - Journal of Medicinal Chemistry
IS - 15
ER -