De Novo Design, Synthesis, and Biological Activities of High-Affinity and Selective Non-Peptide Agonists of the δ-Opioid Receptor
作者:Subo Liao、Josue Alfaro-Lopez、Mark D. Shenderovich、Keiko Hosohata、Jun Lin、Xiaoping Li、Dagmar Stropova、Peg Davis、Kevin A. Jernigan、Frank Porreca、Henry I. Yamamura、Victor J. Hruby
DOI:10.1021/jm980374r
日期:1998.11.1
On the basis of the structure-activity relationships of delta-opioid-selective peptide ligands and on a model of the proposed bioactive conformation for a potent and selective, conformationally constrained delta-opioid peptide ligand [(2S,3R)-TMT1]DPDPE, a series of small organic peptide mimetic compounds targeted for the delta-opioid receptor have been designed, synthesized, and evaluated in radiolabeled ligand binding assays and in vitro bioassays. The new non-peptide ligands use piperazine as a template to present the most important pharmacophore groups, including phenol and phenyl groups and a hydrophobic moiety. This hydrophobic group was designed to mimic the hydrophobic character of the D-Pen residues in DPDPE, which has been found to be extremely important for increasing the binding affinity and selectivity of these non-peptide ligands for the delta-opioid receptor over the mu-opioid receptor. Compound 6f (SL-3111) showed 8 nM binding affinity and over 2000-fold selectivity for the delta-opioid receptor over the delta-opioid receptor. Both enantiomers of SL-3111 were separated, and the (-)-isomer was shown to be the compound with the highest affinity for the delta-opioid receptor found in our study (IC50 = 4.1 nM), with a selectivity very similar to that observed for the racemic compound. The phenol hydroxyl group of SL-3111 turned out to be essential to maintain high affinity for the delta-opioid receptor, which also was observed in the case of the delta-opioid-selective peptide ligand DPDPE. Binding studies of SL-3111 and [p-C1Phe(4)]DPDPE on the cloned wild-type and mutated human delta-opioid receptors suggested that the new non-peptide ligand has a binding profile similar to that of DPDPE but different from that of (+)-4-[((alpha R)-alpha(2S,5R)-4-allyl-2,5-dimethyl-1-piperazinyl)-3-methoxybenzyl] -N,N-diethylbenzamide (SNC-80), another; delta-opioid-selective non-peptide ligand.