title: Internalization of CCR4 and inhibition of chemotaxis by K777, a potent and selective CCR4 antagonist.
abstract: CC chemokine receptor 4 (CCR4) is a G protein-coupled receptor that regulates the chemotaxis of Th2 lymphocytes, which are key players in allergic diseases. K777 is a small compound identified in a binding assay using a CCR4 ligand, CCL17. K777 inhibited both CCL17 binding and CCL17-induced chemotaxis in Hut78 cells (IC50: 57 and 8.9 nmol/l, respectively). The K777-mediated inhibition of chemotaxis was potent even in the presence of a 10-fold higher concentration of CCL17. The imaging and flow cytometric analyses revealed that K777 induced CCR4 internalization, with a ∼50% reduction of cell surface CCR4. K777 did not inhibit CXCR4-induced chemotaxis or internalization and did not bring about Ca(2+) mobilization by itself. A Scatchard plot analysis of the binding assay using radiolabeled K777 revealed a single high-affinity binding site on the CCR4 molecule. These results indicate that K777 is a selective CCR4 antagonist featuring the potent chemotaxis inhibition, to which the internalization-inducible ability of K777 to hide a part of cell surface CCR4 may contribute.
authors.affiliation: Drug Discovery Research Laboratories, Fuji Research Park, Kyowa Hakko Kirin Co., Ltd., Nagaizumi, Japan.
authors.forename: Takashi
authors.initials: T
authors.lastname: Sato
authors.forename: Miho
authors.initials: M
authors.lastname: Iwase
authors.forename: Motoki
authors.initials: M
authors.lastname: Miyama
authors.forename: Masato
authors.initials: M
authors.lastname: Komai
authors.forename: Etsuo
authors.initials: E
authors.lastname: Ohshima
authors.forename: Akira
authors.initials: A
authors.lastname: Asai
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Yano
authors.forename: Ichiro
authors.initials: I
authors.lastname: Miki
mesh_terms: D045744:Cell Line, Tumor; D002464:Cell Migration Inhibition; D054414:Chemokine CCL17 / Q000378:metabolism; D004151:Dipeptides / Q000494:pharmacology*; D006801:Humans; D010649:Phenylalanine / Q000031:analogs & derivatives; D010879:Piperazines; D054398:Receptors, CCR4 / Q000037:antagonists & inhibitors* / Q000378:metabolism; D019718:Receptors, CXCR4 / Q000378:metabolism; D014105:Tosyl Compounds; D014753:Vinyl Compounds / Q000494:pharmacology*
chemical_list: C106230:CCL17 protein, human; C515354:CCR4 protein, human; C527276:CXCR4 protein, human; D054414:Chemokine CCL17; D004151:Dipeptides; D010879:Piperazines; D054398:Receptors, CCR4; D019718:Receptors, CXCR4; D014105:Tosyl Compounds; D014753:Vinyl Compounds; C487484:N-pip-phenylalanine-homophenylalanine-vinyl sulfone phenyl; D010649:Phenylalanine