RESUMO
The diastereoselective synthesis and biological activity of piperidine-3,4-diol and piperidine-3-ol-derived pyrrolotriazine inhibitors of anaplastic lymphoma kinase (ALK) are described. Although piperidine-3,4-diol and piperidine-3-ol derivatives showed comparable in vitro ALK activity, the latter subset of inhibitors demonstrated improved physiochemical and pharmacokinetic properties. Furthermore, the stereochemistry of the C3 and C4 centers had a marked impact on the in vivo inhibition of ALK autophosphorylation. Thus, trans-4-aryl-piperidine-3-ols (22) were more potent than the cis diastereomers (20).
Assuntos
Antineoplásicos/química , Antineoplásicos/uso terapêutico , Linfoma Anaplásico de Células Grandes/tratamento farmacológico , Pirróis/química , Pirróis/uso terapêutico , Receptores Proteína Tirosina Quinases/antagonistas & inibidores , Triazinas/química , Triazinas/uso terapêutico , Quinase do Linfoma Anaplásico , Animais , Antineoplásicos/farmacocinética , Linhagem Celular Tumoral , Cristalografia por Raios X , Humanos , Linfoma Anaplásico de Células Grandes/enzimologia , Camundongos SCID , Modelos Moleculares , Piperidinas/química , Piperidinas/farmacocinética , Piperidinas/uso terapêutico , Inibidores de Proteínas Quinases/química , Inibidores de Proteínas Quinases/farmacocinética , Inibidores de Proteínas Quinases/uso terapêutico , Pirróis/farmacocinética , Ratos Sprague-Dawley , Receptores Proteína Tirosina Quinases/metabolismo , Triazinas/farmacocinéticaRESUMO
Eltrombopag is a first-in-class, orally bioavailable, small-molecule, nonpeptide agonist of the thrombopoietin receptor (TpoR), which is being developed as a treatment for thrombocytopenia of various etiologies. In vitro studies have demonstrated that the activity of eltrombopag is dependent on expression of TpoR, which activates the signaling transducers and activators of transcription (STAT) and mitogen-activated protein kinase signal transduction pathways. The objective of this preclinical study is to determine if eltrombopag interacts selectively with the TpoR to facilitate megakaryocyte differentiation in platelets. Functional thrombopoietic activity was demonstrated by the proliferation and differentiation of primary human CD34(+) bone marrow cells into CD41(+) megakaryocytes. Measurements in platelets in several species indicated that eltrombopag specifically activates only the human and chimpanzee STAT pathways. The in vivo activity of eltrombopag was demonstrated by an increase of up to 100% in platelet numbers when administered orally (10 mg/kg per day for 5 days) to chimpanzees. In conclusion, eltrombopag interacts selectively with the TpoR without competing with Tpo, leading to the increased proliferation and differentiation of human bone marrow progenitor cells into megakaryocytes and increased platelet production. These results suggest that eltrombopag and Tpo may be able to act additively to increase platelet production.
