Shin-ichi Ogino

Discovery of potent CCR4 antagonists: Synthesis and structure-activity relationship study of 2,4-diaminoquinazolines.

A new series of quinazolines that function as CCR4 antagonists were discovered during the screening of our corporate compound libraries. Subsequent compound optimization elucidated the structure-activity relationships and led the identification of 2-(1,4-bipiperidine-1-yl)-N-cycloheptyl-6,7-dimethoxyquinazolin-4-amine 14a, which showed potent inhibition in the [(35)S]GTPgammaS-binding assay (IC(50)=18nM). This compound also inhibited the chemotaxis of human and mouse CCR4-expressing cells (IC(50)=140nM, 39nM).

Potent and orally bioavailable CCR4 antagonists: Synthesis and structure-activity relationship study of 2-aminoquinazolines.

Starting with a series of CC chemokine receptor-4 (CCR4) antagonists developed in a previous study, the potency was improved by replacing the pyrrolidine moiety of N-(4-chlorophenyl)-6,7-dimethoxy-2-(4-pyrrolidin-1-ylpiperidin-1-yl)quinazolin-4-amine 2 with a 3-(hydroxymethyl)piperidine. The resulting compound (1-{4-[(4-chlorophenyl)amino]-6,7-dimethoxyquinazolin-2-yl}-1,4-bipiperidin-3-yl)methanol 8ic was a strong inhibitor of human/mouse chemotaxis. Oral administration of 8ic showed anti-inflammatory activity in a murine model of acute dermatitis (oxazolone-induced contact hypersensitivity test) in a dose-dependent manner.

Potent CCR4 antagonists: synthesis, evaluation, and docking study of 2,4-diaminoquinazolines.

A series of CC chemokine receptor-4 (CCR4) antagonists were examined in a previous report in an attempt to improve metabolic stability in human liver microsomes. In this study, the cycloheptylamine moiety of N-cycloheptyl-6,7-dimethoxy-2-(4-pyrrolidin-1-ylpiperidin-1-yl)quinazolin-4-amine 1 was replaced with the p-chloroaniline moiety, and the resulting compound, N-(4-chlorophenyl)-6,7-dimethoxy-2-(4-pyrrolidin-1-ylpiperidin-1-yl)quinazolin-4-amine (8c), retained its potency ([(35)S]GTPgammaS-binding inhibition and CCL22-induced chemotaxis in humans/mice). Based on the structure-activity relationships (SAR), a homology model was constructed for CCR4 to explain the binding mode of 8c. Overall, there was good agreement between the docking pose of the CCR4 homology model and the human [(35)S]GTPgammaS assay results. Administration of 8c in a murine model of acute dermatitis showed anti-inflammatory activity (oxazolone-induced contact hypersensitivity test).

Systemic administration of 5-HT2C receptor agonists attenuates muscular hyperalgesia in reserpine-induced myalgia model

Fibromyalgia is a prevalent musculoskeletal disorder characterized by chronic widespread pain that significantly reduces quality of life in patients. Due to the lack of consistently effective treatment, the development of improved therapies for treating fibromyalgia is necessary. As dysfunction of serotonergic analgesic control appears to be involved in the pathophysiology of fibromyalgia, the present study explored the potential of 5-HT(2C) receptor agonists as novel therapies for treating this disease. Three 5-HT(2C) receptor agonists (lorcaserin, vabicaserin and YM348) that have been suggested to be useful in the treatment of several central nervous system diseases, including obesity and schizophrenia, were used. The effect of systemic administration of these agents on the muscular hyperalgesia that develops in the reserpine-induced myalgia (RIM) rat, a putative animal model of fibromyalgia, was investigated. RIM rats exhibited decreased muscle pressure thresholds. Microdialysis experiments showed that the concentration of serotonin (5-HT) in the spinal cord of RIM rats was significantly lower than that of controls. Lorcaserin (0.3-3 mg/kg p.o.), vabicaserin (0.3-3 mg/kg s.c.) and YM348 (0.03-0.3 mg/kg p.o.) recovered the muscle pressure threshold. The effect of lorcaserin was reversed by the pretreatment with SB242084, a 5-HT(2C) receptor antagonist. Our findings demonstrate that 5-HT(2C) receptors play a critical role in muscular hyperalgesia in RIM rats and suggest that 5-HT(2C) receptor agonists have therapeutic potential for treating chronic pain in patients with fibromyalgia although clinical extrapolation remains to be a future challenge.