CP-481,715, a Potent and Selective CCR1 Antagonist with Potential Therapeutic Implications for Inflammatory Diseases
Journal of Biological Chemistry
The chemokines CCL3 and CCL5, as well as their shared receptor CCR1, are believed to play a role in the pathogenesis of several inflammatory diseases including rheumatoid arthritis, multiple sclerosis, and transplant rejection. In this study we describe the pharmacological properties of a novel small molecular weight CCR1 antagonist, CP-481,715 (quinoxaline-2-carboxylic acid [4(R)-carbamoyl-1(S)-(3-fluorobenzyl)-2(S),7-dihydroxy-7-methyloctyl]amide). Radiolabeled binding studies indicate that
... -481,715 binds to human CCR1 with a K d of 9.2 nM and displaces 125 I-labeled CCL3 from CCR1-transfected cells with an IC 50 of 74 nM. CP-481,715 lacks intrinsic agonist activity but fully blocks the ability of CCL3 and CCL5 to stimulate receptor signaling (guanosine 5-O-(thiotriphosphate) incorporation; IC 50 ؍ 210 nM), calcium mobilization (IC 50 ؍ 71 nM), monocyte chemotaxis (IC 50 ؍ 55 nM), and matrix metalloproteinase 9 release (IC 50 ؍ 54 nM). CP-481,715 retains activity in human whole blood, inhibiting CCL3-induced CD11b up-regulation and actin polymerization (IC 50 ؍ 165 and 57 nM, respectively) on monocytes. Furthermore, it behaves as a competitive and reversible antagonist. CP-481,715 is >100-fold selective for CCR1 as compared with a panel of G-protein-coupled receptors including related chemokine receptors. Evidence for its potential use in human disease is suggested by its ability to inhibit 90% of the monocyte chemotactic activity present in 11/15 rheumatoid arthritis synovial fluid samples. These data illustrate that CP-481,715 is a potent and selective antagonist for CCR1 with therapeutic potential for rheumatoid arthritis and other inflammatory diseases.