RESUMO
Preclinical antithrombotic efficacy and bleeding models have demonstrated that P2Y1 antagonists are efficacious as antiplatelet agents and may offer a safety advantage over P2Y12 antagonists in terms of reduced bleeding liabilities. In this article, we describe the structural modification of the tert-butyl phenoxy portion of lead compound 1 and the subsequent discovery of a novel series of conformationally constrained ortho-anilino diaryl ureas. In particular, spiropiperidine indoline-substituted diaryl ureas are described as potent, orally bioavailable small-molecule P2Y1 antagonists with improved activity in functional assays and improved oral bioavailability in rats. Homology modeling and rat PK/PD studies on benchmark compound 3l will also be presented. Compound 3l was our first P2Y1 antagonist to demonstrate a robust oral antithrombotic effect with mild bleeding liability in the rat thrombosis and hemostasis models.
Assuntos
Desenho de Fármacos , Conformação Molecular , Compostos de Fenilureia/farmacologia , Compostos de Fenilureia/farmacocinética , Antagonistas do Receptor Purinérgico P2Y/farmacologia , Antagonistas do Receptor Purinérgico P2Y/farmacocinética , Receptores Purinérgicos P2Y1/metabolismo , Compostos de Espiro/farmacologia , Compostos de Espiro/farmacocinética , Ureia/farmacologia , Ureia/farmacocinética , Animais , Disponibilidade Biológica , Humanos , Indóis/química , Modelos Moleculares , Compostos de Fenilureia/química , Compostos de Fenilureia/metabolismo , Antagonistas do Receptor Purinérgico P2Y/química , Antagonistas do Receptor Purinérgico P2Y/metabolismo , Ratos , Ratos Sprague-Dawley , Receptores Purinérgicos P2Y1/química , Homologia de Sequência de Aminoácidos , Compostos de Espiro/química , Compostos de Espiro/metabolismo , Ureia/química , Ureia/metabolismoRESUMO
Two distinct G protein-coupled purinergic receptors, P2Y1 and P2Y12, mediate ADP-driven platelet activation. The clinical effectiveness of P2Y12 blockade is well established. Recent preclinical data suggest that P2Y1 and P2Y12 inhibition provide equivalent antithrombotic efficacy, while targeting P2Y1 has the potential for reduced bleeding liability. In this account, the discovery of a 2-(phenoxypyridine)-3-phenylurea chemotype that inhibited ADP-mediated platelet aggregation in human blood samples is described. Optimization of this series led to the identification of compound 16, 1-(2-(2-tert-butylphenoxy)pyridin-3-yl)-3-4-(trifluoromethoxy)phenylurea, which demonstrated a 68 ± 7% thrombus weight reduction in an established rat arterial thrombosis model (10 mg/kg plus 10 mg/kg/h) while only prolonging cuticle and mesenteric bleeding times by 3.3- and 3.1-fold, respectively, in provoked rat bleeding time models. These results suggest that a P2Y1 antagonist could potentially provide a safe and efficacious antithrombotic profile.
Assuntos
Fibrinolíticos/síntese química , Compostos de Fenilureia/síntese química , Antagonistas do Receptor Purinérgico P2Y/síntese química , Piridinas/síntese química , Ureia/análogos & derivados , Animais , Arteriopatias Oclusivas/sangue , Arteriopatias Oclusivas/tratamento farmacológico , Tempo de Sangramento , Fibrinolíticos/química , Fibrinolíticos/farmacologia , Células HEK293 , Humanos , Masculino , Compostos de Fenilureia/química , Compostos de Fenilureia/farmacologia , Agregação Plaquetária/efeitos dos fármacos , Antagonistas do Receptor Purinérgico P2Y/química , Antagonistas do Receptor Purinérgico P2Y/farmacologia , Piridinas/química , Piridinas/farmacologia , Ratos , Relação Estrutura-Atividade , Trombose/sangue , Trombose/tratamento farmacológico , Ureia/síntese química , Ureia/química , Ureia/farmacologiaRESUMO
For quite some time, the majority of GPCR models have been based on a single template structure: dark-adapted bovine rhodopsin. The recent solution of ß2AR, ß1AR and adenosine A(2A) receptor crystal structures has dramatically expanded the GPCR structural landscape and provided many new insights into receptor conformation and ligand binding. They will serve as templates for the next generation of GPCR models, but also allow direct validation of previous models and computational techniques. This review summarizes key findings from the new structures, comparison of existing models to these structures and highlights new models constructed from these templates.
Assuntos
Modelos Moleculares , Receptor A2A de Adenosina/química , Receptores Adrenérgicos beta 2/química , Receptores Acoplados a Proteínas G/química , Rodopsina/química , Animais , Bovinos , Cristalização , Ligantes , Conformação MolecularRESUMO
The identification of a new series of selective nonsteroidal progesterone receptor (PR) agonists is reported. Using a high-throughput screening assay based on the measurement of transactivation of a mouse mammary tumor virus promoter-driven luciferase reporter (MMTV-Luc) in human breast cancer T47D cells, a benzimidazole-2-thione analog was identified. Compound 1 showed an apparent EC50 of 53 nM and efficacy of 93% with respect to progesterone. It binds to PR with high affinity (Ki nM), but had no or very low affinity for other steroid hormone receptors. Structure-activity relationship studies of a series of benzimidazole-2-thione analogs revealed critical positions for high PR binding affinity and transactivation potency as well as receptor selectivity, as exemplified by 25. Compound 25 binds to human PR with high affinity (Ki nM) and had at least > 1000-fold selectivity for PR versus other steroid receptors. Molecular modeling studies suggested that these agonists overlap favorably with progesterone in the ligand-binding domain of PR. In T47D cells, compound 25 acted as a full agonist in the MMTV-Luc reporter assay, as well as in the induction of endogenous alkaline phosphatase activity with apparent EC50 values of 4 and 9 nM, respectively. In the immature rat model, compound 25 provided a significant suppression of estrogen-induced endometrium hypertrophy as measured by luminal epithelial height. In contrast, compound 25 was inactive in the luteinizing hormone release assay in young ovariectomized rats. These benzimidazole-2-thione analogs constitute a new series of nonsteroidal PR agonists with an excellent steroid receptor selectivity profile. The differential activities observed in the in vivo progestogenic assays in rat models suggest that these analogs can act as selective PR modulators.