Design, synthesis, and biological evaluation of scaffold-based tripeptidomimetic antagonists for CXC chemokine receptor 4 (CXCR4)

Abstract

Structure–activity relationship studies of the cyclopentapeptide CXCR4 antagonists (cyclo(-l-/d-Arg1-Arg2-2-Nal3-Gly4-d-Tyr5-)) suggest that the l-/d-Arg1-Arg2-2-Nal3 tripeptide sequence contained within these cyclopentapeptides serves as a recognition motif for peptidic CXCR4 antagonists. Starting by dissecting the cyclopentapeptide structure and reintroducing cyclic constraints in a stepwise manner, we here report a novel class of scaffold-based tripeptidomimetic CXCR4 antagonists based on the d-Arg-Arg-2-Nal motif. Biological testing of the prototype compounds showed that they represent new peptidomimetic hits; importantly, the modular nature of the scaffold provides an interesting starting point for future ligand optimization.