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
Eg5 is a kinesin whose inhibition leads to cycle arrest during mitosis, making it a potential therapeutic target in cancers. Circular dichroism and isothermal titration calorimetry of our pyrrolotriazine-4-one series of inhibitors with Eg5 motor domain revealed enhanced binding in the presence of adenosine 5'-diphosphate (ADP). Using this information, we studied the interaction of this series with ADP-Eg5 complexes using a thermal shift assay. We measured up to a 7 degrees C increase in the thermal melting (T(m)) of Eg5 for an inhibitor that produced IC(50) values of 60 and 130 nM in microtubule-dependent adenosine triphosphatase (ATPase) and cell-based cytotoxicity assays, respectively. In general, the inhibitor potency of the pyrrolotriazine-4-one series in in vitro biological assays correlated with the magnitude of the thermal stability enhancement of ADP-Eg5. The thermal shift assay also confirmed direct binding of Eg5 inhibitors identified in a high-throughput screen and demonstrated that the thermal shift assay is applicable to a range of chemotypes and can be useful in evaluating both potent (nM) and relatively weakly binding (microM) leads. Overall, the thermal shift assay was found to be an excellent biophysical method for evaluating direct binding of a large number of compounds to Eg5, and it complemented the catalytic assay screens by providing an alternative determination of inhibitor potency.
Assuntos
Bioquímica/métodos , Cinesinas/química , Pirróis/análise , Pirróis/química , Triazinas/análise , Triazinas/química , Difosfato de Adenosina/metabolismo , Fenômenos Biofísicos , Calorimetria , Linhagem Celular Tumoral , Dicroísmo Circular , Humanos , Cinesinas/metabolismo , Espectroscopia de Ressonância Magnética , Modelos Moleculares , Ligação Proteica , Desnaturação Proteica , Dobramento de Proteína , Estrutura Terciária de Proteína , TemperaturaRESUMO
Synthesis and SAR of substituted pyrrolotriazine-4-one analogues as Eg5 inhibitors are described. Many of these analogues displayed potent inhibitory activities in the Eg5 ATPase and A2780 cell proliferation assays. In addition, pyrrolotriazine-4-one analogue 26 demonstrated in vivo efficacy in an iv P388 murine leukemia model. Both NMR and X-ray crystallographic studies revealed that these analogues bind to an allosteric site on the Eg5 protein.
Assuntos
Cinesinas/antagonistas & inibidores , Pirróis/síntese química , Pirróis/farmacologia , Animais , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Cristalografia por Raios X , Humanos , Espectroscopia de Ressonância Magnética , Camundongos , Modelos Moleculares , Pirróis/química , Relação Estrutura-AtividadeRESUMO
In a high-throughput screening effort, a series of tetrahydroisoquinolines was identified as modest inhibitors of human Eg5. A medicinal chemistry optimization effort led to the identification of R-4-(3-hydroxyphenyl)-N,N-7,8-tetramethyl-3,4-dihydroisoquinoline-2(1H)-carboxamide (32a) as a potent inhibitor of human Eg5 (ATPase IC50 104 nM) with good anti-proliferative activity in A2780 cells (IC50 234 nM).