Identification of a series of CCK-2 receptor nonpeptide agonists: sensitivity to stereochemistry and a receptor point mutation.
The search for small-molecule drugs that act at peptide hormone receptors has resulted in the identification of a wide variety of antagonists. In contrast, the discovery of nonpeptide agonists has been far more elusive. We have used a constitutively active mutant of the cholecystokinin 2 receptor (CCK-2R) as a sensitive screen to detect ligand activity. Functional assessment of structural analogs of the prototype CCK-2R antagonist, L-365,260 [3R-N- (2,3-dihydro-1-methyl-2-oxo-5-phenyl-1H-1,4-benzodiazepin-3-yl)-N'-(3-methylphenyl)urea], resulted in the identification of a series of agonists. Each of the active molecules is an S enantiomer, whereas the corresponding R stereoisomers have little or no activity. Further in vitro and in vivo assessment at the wild-type receptor indicated that efficacy of the two most active ligands approached that of the endogenous hormone. The function of selected R and S enantiomers was differentially sensitive to a point mutation, N353L, within the putative CCK-2R ligand pocket. The results of this study highlight the potential of constitutively active receptors as drug screening tools and the interdependence of ligand stereochemistry and receptor conformation in defining drug efficacy.
Kopin
Alan S
AS
Molecular Pharmacology Research Center, Department of Medicine, Tufts-New England Medical Center, 750 Washington Street, Box 7703, Boston, MA 02111, USA. akopin@tufts-nemc.edu
McBride
Edward W
EW
Chen
Ci
C
Freidinger
Roger M
RM
Chen
Duan
D
Zhao
Chun-Mei
CM
Beinborn
Martin
M
D000818:Animals; D001570:Benzodiazepinones / Q000737:chemistry / Q000494:pharmacology*; D019556:COS Cells; D006801:Humans; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D010671:Phenylurea Compounds / Q000737:chemistry / Q000494:pharmacology*; D017354:Point Mutation; D043887:Receptor, Cholecystokinin B; D011949:Receptors, Cholecystokinin / Q000819:agonists* / Q000037:antagonists & inhibitors; D011994:Recombinant Proteins / Q000819:agonists / Q000037:antagonists & inhibitors; D013237:Stereoisomerism
D001570:Benzodiazepinones; D010671:Phenylurea Compounds; D043887:Receptor, Cholecystokinin B; D011949:Receptors, Cholecystokinin; D011994:Recombinant Proteins; C058121:L 365260