CC Chemokine Receptor 4 Antagonist Research Articles

Suppressive effects of a novel CC chemokine receptor 4 antagonist on Th2 cell trafficking in ligand- and antigen-induced mouse models

CC chemokine receptor 4 (CCR4) has been implicated as a preferential marker for T helper type 2 (Th2) cells, and is believed to be involved in the pathology of allergic diseases by controlling Th2 cell trafficking into inflamed tissues. The objective of the study was to characterize the pharmacological properties of E0001-163, a novel CCR4 antagonist. E0001-163 was tested in both in vitro chemotaxis assays as well as in vivo mouse models of CCR4 ligand-induced air pouch and antigen-induced airway inflammation by utilizing in vitro-polarized Th2 cells. In vitro, E0001-163 inhibited migratory response of human Th2-polarized cells to CCL22, a CCR4 ligand, with an IC50 value of 11.9nM. E0001-163 significantly suppressed CCL22-induced Th2 cell trafficking into mouse air pouch in a dose-dependent manner at doses of 3 and 10mg/kg, suggesting that E0001-163 has an inhibitory effect on CCR4-mediated T cell trafficking in vivo. In addition, E0001-163 partially decreased Th2 cell trafficking and the level of IL-4 in the lungs in Th2-tansferred and ovalbumin (OVA)-challenged mice. T cell trafficking involves multiple chemokine receptors both in acute and chronic phases, and our findings suggest that CCR4, together with other chemokine receptors, may be involved in Th2 cell trafficking under disease conditions.

Relationship Between the Chemokine Receptor CCR5 and Microglia in Neurological Disorders: Consequences of Targeting CCR5 on Neuroinflammation, Neuronal Death and Regeneration in a Model of Epilepsy

Chemokines may play a role in leukocyte migration across the blood-brain barrier (BBB) during neuroinflammation and other neuropathological processes, such as epilepsy. The CC chemokine receptor 5 (CCR5) is a member of CC-chemokine receptor family that binds several chemokines, including CCL3 (macrophage inflammatory protein-1alpha, MIP-1alpha), CCL4 (macrophage inflammatory protein-1beta, MIP-1beta) and CCL5 (RANTES). The current review examines the relationship between CCR5 and the microglia in different neurological disorders and models of CNS injury. CCR5 expression is upregulated in different neurological diseases, where it is often immunolocalized in microglial cells. A multistep cascade couples CCR5 activation by chemokines to Ca(2+) increases in human microglia. Because changes in [Ca(2+)] (i) affect chemotaxis, secretion, and gene expression, pharmacologic modulation of this pathway may alter inflammatory and degenerative processes in the CNS. Consequently, targeting CCR5 by using CCR5 antagonists may attenuate critical aspects of neuroinflammation in different models of neurological disorders. To illustrate the interaction between CCR5 and microglia in the CNS, we used a model of excitotoxicity, and demonstrate the intimate involvement of CCR5 in neuron injury and inflammation attendant to kainic acid (KA)-induced neurotoxicity. CCR5 participates in neuronal injury caused by the excitotoxin, KA, brings inflammatory cells to the sites of KA-induced CNS injury, defines the extent of tissue loss after KA exposure and limits reparative responses. We used a SV40-derived vector carrying an interfering RNA (RNAi) that targets CCR5. Delivered directly to the bone marrow, this vector decreased CCR5 expression in circulating cells. Animals so treated showed greatly reduced expression of CCR5 and its ligands (MIP-1alpha and RANTES) in the CNS, including in the brain vasculature, decreased BBB leakage, demonstrated greater KA-stimulated neurogenesis and increased migration of bone marrow-derived cells to the brain to become neurons. Thus, therapeutic targeting of CCR5 may allow control of potentially injurious neuroinflammatory responses, including decrease in microglial cells activation and proliferation, and facilitate neurogenic repair in seizure-induced and, potentially, other forms of CNS injury.

Internalization of CCR4 and Inhibition of Chemotaxis by K777, a Potent and Selective CCR4 Antagonist

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 Ca²⁺ 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.

Safety, tolerability, pharmacokinetics and pharmacodynamics of GSK2239633, a CC-chemokine receptor 4 antagonist, in healthy male subjects: results from an open-label and from a randomised study.

BackgroundThe CC-chemokine receptor 4 (CCR4) is thought potentially to play a critical role in asthma pathogenesis due to its ability to recruit type 2 T-helper lymphocytes to the inflamed airways. Therefore, CCR4 provides an excellent target for anti-inflammatory therapy.MethodsThe safety, tolerability, pharmacokinetics and pharmacodynamics of the CCR4 antagonist GSK2239633, N-(3-((3-(5-chlorothiophene-2-sulfonamido)-4-methoxy-1H-indazol-1-yl)methyl)benzyl)-2-hydroxy-2-methylpropanamide, were examined in healthy males. Two studies were performed: 1) an open-label, study in which six subjects received a single intravenous infusion of [14C]-GSK2239633 100 μg (10 kBq) (NCT01086462), and 2) a randomised, double-blind, placebo-controlled, cross-over, ascending dose study in which 24 subjects received single oral doses of GSK2239633 150–1500 mg (NCT01371812).ResultsFollowing intravenous dosing, plasma GSK2239633 displayed rapid, bi-phasic distribution and slow terminal elimination (t½: 13.5 hours), suggesting that GSK2239633 was a low to moderate clearance drug. Following oral dosing, blood levels of GSK2239633 reached Cmax rapidly (median tmax: 1.0–1.5 hours). Estimated GSK2239633 bioavailability was low with a maximum value determined of only 16%. Food increased GSK2239633 systemic exposure (as assessed by AUC and Cmax). Increases in AUC and Cmax were less than dose proportional. Adverse events were reported by three subjects (50%) following intravenous administration, and by 19 subjects (79%) following oral administration; most (46/47; 98%) events were mild/moderate in intensity. GSK2239633 1500 mg inhibited thymus- and activation-regulated chemokine-induced (TARC) actin polymerisation reaching a mean CCR4 occupancy of 74%.ConclusionIn conclusion, GSK2239633 was well-tolerated and capable of inhibiting TARC from activating the CCR4 receptor.

Computational studies of the binding modes of CCR1 antagonists

The CC chemokine receptor 1 (CCR1) is linked to the pathogenesis of chronic inflammatory diseases and is an attractive target for drug discovery research. On the basis of the high-resolution crystal structure of CXC4 chemokine receptor, 3D structure of the human CCR1 was developed by homology modelling. Nine representative antagonists were applied to binding site study with the rational model through molecular docking. Three hydrophobic sites, especially Phe89, Trp90; Trp99, Tyr113; Tyr114 and Cys183, were identified to be essential for their strong hydrophobic interactions with antagonists. Lys94 and Glu287 have been identified as major contributor to ligand binding by H-bond interaction and salt-bridge interaction, respectively. Two hydrophobic subpockets (Regions A and B) and Glu287 may be crucial binding sites for chemokine receptors, whereas Tyr93 and Lys94 may be crucial binding sites of the subtype selectivity for CCR1. They are important in stabilising CCR1–antagonist complexes. Thus, our studies should provide novel insights into the CCR1–antagonist interactions and guide further drug design and mutagenesis studies.

Coreceptor usage in different reservoirs

HIV-1 infects tissue macrophages, microglia and other mononuclear phagocytes which represent an important cellular reservoir for viral replication and persistence in macrophage-rich tissue. This compartmentalization allows the virus to exist as genetically distinct quasi-species that can have capacities to use different coreceptors for cell entry. This review assesses the tropism of HIV-1 in different human compartments. The majority of HIV infection occurs with R5-tropic viruses probably due to the selective expression of the R5 cell-surface protein on the target cells in the genital muscosa. There is a large concordance of tropism use between blood cell-associated proviral DNA and RNA plasma viruses, allowing the use of CC chemokine receptor 5 (CCR5) antagonists in patients who have undetectable viral load and for whom HIV tropism was determined in DNA. Most of HIV strains in central nervous system remain R5-tropic allowing the use of CCR5 antagonists. There are many clinical situations in which the use of CCR5 antagonists can be used and several ways to determine HIV tropism in most of the compartments.

Design and Synthesis of a Series of Pyrido[2,3-d]pyrimidine Derivatives as CCR4 Antagonists

A series of pyrido[2,3-d]pyrimidine derivatives were designed and synthesized based on known CC chemokine receptor 4 (CCR4) antagonists. The activities of all the newly synthesized compounds were evaluated using a chemotaxis inhibition assay. Compound 6b was proven to be a potent CCR4 antagonist that can block cell chemotaxis induced by macrophage-derived chemokine (MDC), thymus and activation regulated chemokine (TARC), and CKLF1, the natural ligands of CCR4. In addition, compound 6b is more effective than budesonide in the murine rhinitis model. The intravenous injection LD50 of compound 6b is 175 mg/kg and the oral LD50 is greater than 2,000 mg/kg.

The potential role of anibamine, a natural product CCR5 antagonist, and its analogues as leads toward development of anti-ovarian cancer agents

Chemokines and their receptors play important roles in the development of primary tumors and their metastases. Particularly CC chemokine receptor 5 (CCR5) and its ligand CC chemokine ligand 5 (CCL5/RANTES) seem to be critical in proliferation and invasion of ovarian cancer, the leading cause of death from gynecological malignancies in the United States. Anibamine, the first natural product CCR5 antagonist, and its analogues were examined for their effects on proliferation of the OVCAR-3 ovarian cancer cells in order to validate their candidacy as leads to develop novel anti-ovarian cancer agents. Acting as CCR5 antagonists, anibamine and its analogues significantly suppressed CCL5-induced intracellular Ca2+ flux. The compounds also inhibited the proliferation of OVCAR-3 at micromolar to submicromolar range. Moreover, anibamine and several analogues did not show significant cytotoxicity in NIH 3T3 cells at concentrations up to 20μM. Based on these results, anibamine and one of its synthetic analogues were defined as potential leads to develop novel agents against ovarian cancer.

Screening of chemokine receptor CCR4 antagonists by capillary zone electrophoresis

CC chemokine receptor 4 (CCR4) is a kind of G-protein-coupled receptor, which plays a pivotal role in allergic inflammation. The interaction between 2-(2-(4-chloro-phenyl)-5-{[(naphthalen-1-ylmethyl)-carbamoyl]-methyl}-4-oxo-thiazolidin-3-yl)-N-(3-morpholin-4-yl-propyl)-acetamide (S009) and the N-terminal extracellular tail (ML40) of CCR4 has been validated to be high affinity by capillary zone electrophoresis (CZE). The S009 is a known CCR4 antagonist. Now, a series of new thiourea derivatives have been synthesized. Compared with positive control S009, they were screened using ML40 as target by CZE to find some new drugs for allergic inflammation diseases. The synthesized compounds XJH-5, XJH-4, XJH-17 and XJH-1 displayed the interaction with ML40, but XJH-9, XJH-10, XJH-11, XJH-12, XJH-13, XJH-14, XJH-3, XJH-8, XJH-6, XJH-7, XJH-15, XJH-16 and XJH-2 did not bind to ML40. Both qualification and quantification characterizations of the binding were determined. The affinity of the four compounds was valued by the binding constant, which was similar with the results of chemotactic experiments. The established CEZ method is capable of sensitive and fast screening for a series of lactam analogs in the drug discovery for allergic inflammation diseases.

Therapeutic compounds: patent evaluation of WO2011011652A1

A series of sulfonamide derivatives, incorporating azabicyclo[3.2.1]octane and phenyl-propyl scaffolds, were prepared by a succession of original steps. The compounds are claimed to act as antagonists of the C-C chemokine receptor 5 (CCR5) involved in the entry of HIV-1 to cells, but only semi-quantitative antiviral data are provided. HIV entry inhibitors, including CCR5 antagonists, are clinically used for the treatment of this viral infection; the compounds claimed in the patent, possessing a new and original scaffold, seem to be of interest for developing novel antiviral agents belonging to this class.

Identification and Characterization of INCB9471, an Allosteric Noncompetitive Small-Molecule Antagonist of C-C Chemokine Receptor 5 with Potent Inhibitory Activity against Monocyte Migration and HIV-1 Infection

C-C chemokine receptor 5 (CCR5) is a clinically proven target for inhibition of HIV-1 infection and a potential target for various inflammatory diseases. In this article, we describe 5-[(4-{(3S)-4-[(1R,2R)-2-ethoxy-5-(trifluoromethyl)-2,3-dihydro-1H-inden-1-yl]-3-methylpiperazin-1-yl}-4-methylpiperidin-1-yl)carbonyl]-4,6-dimethylpyrimidine dihydrochloride (INCB9471), a potent and specific inhibitor of human CCR5 that has been proven to be safe and efficacious in viral load reduction in phase I and II human clinical trails. INCB9471 was identified using a primary human monocyte-based radioligand competition binding assay. It potently inhibited macrophage inflammatory protein-1β-induced monocyte migration and infection of peripheral blood mononuclear cells by a panel of R5-HIV-1 strains. The results from binding and signaling studies using incremental amounts of INCB9471 demonstrated INCB9471 as a noncompetitive CCR5 inhibitor. The CCR5 residues that are essential for interaction with INCB9471 were identified by site-specific mutagenesis studies. INCB9471 rapidly associates with but slowly dissociates from CCR5. When INCB9471 was compared with three CCR5 antagonists that had been tested in clinical trials, the potency of INCB9471 in blocking CCR5 ligand binding was similar to those of 4,6-dimethyl-5-{[4-methyl-4-((3S)-3-methyl-4-{(1R0-2-(methyloxy)-1-[4-(trifluoromethyl) phenyl]ethyl}-1-piperazingyl)-1-piperidinyl]carbonyl}pyrimidine (SCH-D; vicriviroc), 4-{[4-({(3R)-1-butyl-3-[(R)-cyclohexyl(hydroxyl)methyl]-2, 5-dioxo-1,4,9-triazaspiro[5.5]undec-9-yl}methyl)phenyl]oxy}benzoic acid hydrochloride (873140; aplaviroc), and 4,4-difluoro-N-((1S)-3-{(3-endo)-3-[3-methyl-5-(1-methylethyl)-4H-1,2,4-triazol-4-yl]-8-azabicyclo[3.2.1]oct-8-yl}-1-phenylpropyl)cyclohexanecarboxamide (UK427857; maraviroc). Its inhibitory activity against CCR5-mediated Ca(2+) mobilization was also similar to those of SCH-D and 873140. Further analysis suggested that INCB9471 and UK427857 may have different binding sites on CCR5. The significance of two CCR5 antagonists with different binding sites is discussed in the context of potentially overcoming drug-resistant HIV-1 strains.

Analyses of Anti-HIV Type 1 Activity of a Small CCR5 Peptide Antagonist

We have identified a small peptide (AFDWTFVPSLIL) that specifically binds to CC chemokine receptor 5 (CCR5) expressed on the Chinese hamster ovary (CHO) cell surface. Here, we further investigate its interaction with CCR5 on activated peripheral blood mononuclear cells (PBMCs), and determine whether the peptide inhibits HIV-1 infection mediated by CCR5 in PBMCs. The peptide antagonized the binding of CCR5 ligands, the second extracellular loop-specific monoclonal antibody (mAb) (2D7), regulated on activation of normal expressed and secreted T cells (RANTES), to PBMCs and blocked CCR5-mediated Ca(2+) signaling elicited by RANTES at a concentration of 10 μg/ml. Moreover, the peptide displayed selective inhibition of R5 HIV-1 replication. We conclude that the peptide is a CCR5 antagonist with anti-HIV-1 activity.

Agonist-Induced Internalization of CC Chemokine Receptor 5 as a Mechanism to Inhibit HIV Replication

The chemokine G protein-coupled receptor CC chemokine receptor 5 (CCR5) is used as an entry gate by CCR5-tropic and dual- or CCR5/CXC chemokine receptor 4-tropic strains of HIV to enter the human host cells. Thus, CCR5 antagonists (i.e., maraviroc) have been proven to be clinically effective by preventing the interaction between viral glycoprotein 120 and CCR5 and thus impeding viral entry into host cells. However, the emergence of HIV strains resistant to CCR5 antagonists has been reported in vitro and in vivo, where the virus has adapted to enter the cells via antagonist-bound CCR5. An alternative strategy that should obviate this mode of viral resistance would entail the ablation of the CCR5 portal for HIV entry from the cell surface through agonist-induced receptor internalization. Although this protective effect has been demonstrated clearly with natural CCR5 ligands, the chemoattractant properties of these chemokines have precluded them from further consideration in terms of drug development. Thus, we sought to explore the possibility of developing novel small molecules and selective CCR5 agonists devoid of eliciting chemotaxis. Indeed, the CCR5 agonists described herein were found to induce profound down-modulation of CCR5 (and not CXC chemokine receptor 4) from the cell surface and its sustained sequestration in the intracellular compartment without inducing chemotaxis in vitro. The bioactivity profile of these novel CCR5 agonists is exemplified by the compound (R)-2-(4-cyanophenyl)-N-(1-(1-(N,1-diphenylmethylsulfonamido)propan-2-yl)piperidin-4-yl)acetamide (ESN-196) that potently inhibits HIV-1 infection in human peripheral blood mononuclear cells and macrophages in vitro with potencies comparable to that of maraviroc and moreover demonstrates full activity against a maraviroc-resistant HIV-1 RU570 strain.

Genotypic Tests for Determining Coreceptor Usage of HIV-1

Genotypic Tests for Determining Coreceptor Usage of HIV-1

Screening of thiourea derivatives and carbonyl-2-aminothiazole derivatives for potential CCR4 antagonists using capillary zone electrophoresis

CC chemokine receptor 4 (CCR4) is a kind of G-protein-coupled receptors with a characteristic seven-transmembrane structure and selectively expressed on Th2-type CD4+ T-cells. CCR4 has been identified as a potentially important drug target for the treatment of T cell-mediated allergic inflammatory diseases. In this study, a novel series of CCR4 antagonists were screened by investigating the interactions between the compounds and the human CCR4 N-terminal peptide ML40 using capillary zone electrophoresis (CZE) for the first time. Both qualitative and quantitative characterizations of the compound-peptide binding were determined. The results showed that, compared with positive control, ten of the compounds were interacted with ML40, which were A3C223, A3C231, A4C238, A3C241, A4C241, A4C239, ZXF0337, ZXF0432, ZXF0519 and ZXF0637A, and their binding constants were calculated from the Scatchard plot by regression. The binding constants of the compounds to ML40 were calculated and the binding constant of ZXF0432 was the largest among them [(7.6334±0.1907)×104M−1]. Here, a sensitive and selective high-performance analytical method based on CZE was developed for screening of thiourea derivatives and C-arbonyl-2-aminothiazole derivatives for potential CCR4 antagonists for the first time. The methodology presented should be generally applicable to study compounds-ML40 interactions as a powerful, sensitive and fast screening method for CCR4 antagonist discovery.

N-aryl pyrazoles, indazoles and azaindazoles as antagonists of CC chemokine receptor 1: patent cooperation treaty applications WO2010/036632, WO2009/134666 and WO2009/137338

Background: CC chemokine receptor 1 (CCR1) is a GPCR involved in the migration and activation of leukocytes. A number of studies have highlighted a role for CCR1 in preclinical animal models of inflammatory diseases, including MS and rheumatoid arthritis.Objective: This review examines three reports on a new series of CCR1 antagonists.Methods: The compounds of the title inventions are put in the context of earlier work in the area of CCR1 antagonism. The structure–activity relationships disclosed in the inventions are also discussed.Conclusions: Several of the compounds disclosed in patent cooperation treaty applications WO 2010/036632, WO 2009/134666 and WO 2009/137338 are sub-nanomolar antagonists of MIP-1α-induced calcium flux in CCR1-bearing cells. Further preclinical studies are required with these new CCR1 antagonists in order to understand their potential for ameliorating human inflammatory diseases.

A Novel CC Chemokine Receptor 4 Antagonist RS-1269 Inhibits Ovalbumin-Induced Ear Swelling and Lipopolysaccharide-Induced Endotoxic Shock in Mice

There is growing evidence that chemokines recruit leukocytes in allergic, inflammatory and immune responses. CC chemokine receptor 4 (CCR4) is implicated as a preferential marker for T helper 2 cells, and the cells selectively respond to CC chemokine ligand 17 (CCL17) and CCL22. We searched for compounds having a profile as a CCR4 antagonist from an in-house library and have previously reported that 3-{2-[(2R)-2-phenyl-4-(4-pyridin-4-ylbenzyl)morpholin-2-yl]ethyl}quinazoline-2,4(1H,3H)-dione (named RS-1154) was capable of significantly inhibiting the binding of [(125) I]CCL17 to human CCR4-expressing CHO cells. From further synthesis of its derivatives, we newly focused on 3-(isobutyrylamino)-N-{2-[(2R)-2-phenyl-4-(4-pyridin-4-ylbenzyl)morpholin-2-yl]ethyl}benzamide (RS-1269), which showed potency comparable to RS-1154 in inhibiting CCL17-induced migration of DO11.10 mice-derived T helper 2 cells with an IC(50) value of 5.5 nM in vitro. We then investigated the pharmacological effects of RS-1269 on ovalbumin-induced ear swelling and lipopolysaccharide-induced endotoxic shock in mice. The ear thickness was significantly decreased by oral administration of RS-1269 at the dose of 30 mg/kg. Treatment with lipopolysaccharide significantly increased the serum level of tumour necrosis factor-α. Compared with an anti-CCL17 antibody, RS-1269 significantly inhibited the production at the dose of 100 mg/kg. These results raise the possibility that RS-1269 or one of its derivatives has potential to serve as a prototype compound to develop therapeutic agents for atopic dermatitis and inflammatory diseases.

CC chemokine receptor 4 (CCR4) in human allergen-induced late nasal responses.

CC Chemokine receptor 4 (CCR4) is preferentially expressed on Th2 lymphocytes. CCR4-mediated inflammation may be important in the pathology of allergic rhinitis. Disruption of CCR4 - ligand interaction may abrogate allergen-induced inflammation. Sixteen allergic rhinitics and six nonatopic individuals underwent both allergen and control (diluent) nasal challenges. Symptom scores and peak nasal inspiratory flow were recorded. Nasal biopsies were taken at 8 h post challenge. Sections were immunostained and examined by light or dual immunofluorescence microscopy for eosinophils, T-lymphocytes, CCR4(+)CD3(+) and CXCR3(+)CD3(+) cells and examined by in situ hybridization for CCR4, IL-4 and IFN-gamma mRNA(+) cells. Peripheral blood mononuclear cells were obtained from peripheral blood of nine normal donors and the CCR4(+)CD4(+) cells assessed for actin polymerization in response to the CCR4 ligand macrophage-derived chemokine (MDC/CCL22) and the influence of a CCR4 antagonist tested. Allergic rhinitics had increased early and late phase symptoms after allergen challenge compared to diluent; nonatopics did not respond to either challenge. Eosinophils, but not total numbers of CD3(+) T cells, were increased in rhinitics following allergen challenge. In rhinitics, there was an increase in CCR4(+)CD3(+) protein-positive cells relative to CXCR3(+)CD3(+) cells; CCR4 mRNA+ cells were increased and IL-4 increased to a greater extent than IFN-gamma. CCR4(+)CD4(+) T cells responded to MDC in vitro, and this response was inhibited by the selective CCR4 antagonist. Lymphocyte CCR4 expression is closely associated with induction of human allergen-induced late nasal responses. Blocking CCR4-ligand interaction may provide a novel therapeutic approach in allergic disease.

RS-1748, a Novel CC Chemokine Receptor 4 Antagonist, Inhibits Ovalbumin-Induced Airway Inflammation in Guinea Pigs

CC chemokine receptor 4 (CCR4) is generally recognized as a preferential marker for T helper 2 cells, and we have previously reported morpholine-derivative CCR4 antagonists, RS-1154 and RS-1269. Here, we investigate the pharmacological profiles of a novel pyrimidine-derivative CCR4 antagonist, 2-{4-[2-(diethylamino)ethoxy]phenyl}-N-(2,4-difluorobenzyl)-5-fluoropyrimidin-4-amine (RS-1748), which showed potency to inhibit the bindings of [(125)I]CCL17 and [(35)S]GTPgammaS to human CCR4-expressing Chinese hamster ovary (CHO) cells with IC(50) values of 59.9 nM and 18.4 nM, respectively. Furthermore, RS-1748 inhibited ovalbumin-induced airway inflammation in guinea pigs at a dose of 10 mg/kg. These results indicate that RS-1748 would be a promising lead compound for developing a therapeutic agent against asthma.

Novel CC chemokine receptor 4 antagonist RS-1154 inhibits ovalbumin-induced ear swelling in mice

CC chemokine ligand 17 (CCL17/thymus and activation-regulated chemokine: TARC) and CCL22 (macrophage-derived chemokine: MDC) selectively bind to CC chemokine receptor 4 (CCR4). The CCR4 system is considered to be responsible for the pathology of allergic diseases such as atopic dermatitis. To find and develop potential medicines against allergic diseases, we screened an in-house library to search for compounds having a profile as a CCR4 antagonist. From among the screening hits, we focused on 3-{2-[(2 R)-2-phenyl-4-(4-pyridin-4-ylbenzyl)morpholin-2-yl]ethyl}quinazoline-2,4(1 H,3 H)-dione (named RS-1154), which had been newly synthesized in our laboratory. This compound inhibited the binding of [ 125I]CCL17 to human CCR4-expressing CHO cells with an IC 50 value of 27.7 nM and moreover inhibited CCL17-induced migration of DO11.10 mice-derived T helper 2 cells with an IC 50 value of 1.5 nM in vitro. We then examined the effect of RS-1154 in an ovalbumin-induced ear swelling assay. The ear thickness was decreased by intravenous administration of anti-CCL17 or anti-CCL22 antibodies, suggesting that the CCR4 system is involved in the ear swelling. Though partially, the oral administration of RS-1154 also significantly ameliorated the ear swelling at the doses of 30 and 100 mg/kg. Furthermore, the serum level of interleukin-4 decreased after the administration of RS-1154. In this study, we succeeded in obtaining a newly-synthesized compound, RS-1154, which has a potential to inhibit the chemotaxis of T helper 2 cells in vitro and to ameliorate ovalbumin-induced ear swelling in vivo. These results raise the possibility that RS-1154 or one of derivatives might become a therapeutic agent for atopic dermatitis patients.