title: Structure-activity relationships of new 1H-imidazo[4,5-c]quinolin-4-amine derivatives as allosteric enhancers of the A3 adenosine receptor.
abstract: 1H-Imidazo[4,5-c]quinolin-4-amine derivatives have been synthesized as allosteric modulators of the human A3 adenosine receptor (AR). Structural modifications were made at the 4-amino and 2 positions. The compounds were tested in both binding and functional assays, and many were found to be allosteric enhancers of the action of A3AR agonists by several different criteria. First, a potentiation of the maximum efficacy of the agonist Cl-IB-MECA was observed for numerous derivatives. Also, a number of these compounds decreased the rate of dissociation of the agonist [125I]I-AB-MECA from the A3AR. Most prominently, compound 43 (LUF6000) was found to enhance agonist efficacy in a functional assay by 45% and decrease dissociation rate similarly without influencing agonist potency. The structural requirements for allosteric enhancement at the A3AR were distinct from the requirements to inhibit equilibrium binding. Thus, we have prepared allosteric enhancers of the human A3AR that have an improved allosteric effect in comparison to the inhibition of equilibrium binding at the orthosteric site.
authors.affiliation: Division of Medicinal Chemistry, Leiden/Amsterdam Center for Drug Research, Leiden University, P.O. Box 9502, 2300 RA, Leiden, The Netherlands.
authors.forename: Anikó
authors.initials: A
authors.lastname: Göblyös
authors.forename: Zhan-Guo
authors.initials: ZG
authors.lastname: Gao
authors.forename: Johannes
authors.initials: J
authors.lastname: Brussee
authors.forename: Roberto
authors.initials: R
authors.lastname: Connestari
authors.forename: Sabrina Neves
authors.initials: SN
authors.lastname: Santiago
authors.forename: Kai
authors.initials: K
authors.lastname: Ye
authors.forename: Adriaan P
authors.initials: AP
authors.lastname: Ijzerman
authors.forename: Kenneth A
authors.initials: KA
authors.lastname: Jacobson
mesh_terms: D058909:Adenosine A3 Receptor Agonists; D000249:Adenosine Monophosphate / Q000096:biosynthesis; D000494:Allosteric Regulation; D000588:Amines / Q000138:chemical synthesis* / Q000737:chemistry / Q000494:pharmacology; D000634:Aminoquinolines / Q000138:chemical synthesis* / Q000737:chemistry / Q000494:pharmacology; D000818:Animals; D001667:Binding, Competitive; D002460:Cell Line; D006224:Cricetinae; D003412:Cricetulus; D006801:Humans; D007093:Imidazoles / Q000138:chemical synthesis* / Q000737:chemistry / Q000494:pharmacology; D011804:Quinolines / Q000138:chemical synthesis* / Q000737:chemistry / Q000494:pharmacology; D011869:Radioligand Assay; D013329:Structure-Activity Relationship
chemical_list: D058909:Adenosine A3 Receptor Agonists; D000588:Amines; D000634:Aminoquinolines; D007093:Imidazoles; C511637:N-(3,4-dichlorophenyl)-2-cyclohexyl-1H-imidazo(4,5-c)quinolin-4-amine; D011804:Quinolines; D000249:Adenosine Monophosphate