RESUMO
mTOR is a critical regulator of cellular signaling downstream of multiple growth factors. The mTOR/PI3K/AKT pathway is frequently mutated in human cancers and is thus an important oncology target. Herein we report the evolution of our program to discover ATP-competitive mTOR inhibitors that demonstrate improved pharmacokinetic properties and selectivity compared to our previous leads. Through targeted SAR and structure-guided design, new imidazopyridine and imidazopyridazine scaffolds were identified that demonstrated superior inhibition of mTOR in cellular assays, selectivity over the closely related PIKK family and improved in vivo clearance over our previously reported benzimidazole series.
Assuntos
Inibidores de Proteínas Quinases/química , Piridazinas/química , Piridinas/química , Serina-Treonina Quinases TOR/antagonistas & inibidores , Animais , Benzimidazóis/química , Sítios de Ligação , Ligação Competitiva , Cristalografia por Raios X , Desenho de Fármacos , Avaliação Pré-Clínica de Medicamentos , Meia-Vida , Humanos , Imidazóis/química , Masculino , Camundongos , Microssomos Hepáticos/metabolismo , Fosfatidilinositol 3-Quinases/metabolismo , Inibidores de Fosfoinositídeo-3 Quinase , Inibidores de Proteínas Quinases/síntese química , Inibidores de Proteínas Quinases/farmacocinética , Estrutura Terciária de Proteína , Piridazinas/síntese química , Piridazinas/farmacocinética , Piridinas/síntese química , Piridinas/farmacocinética , Ratos Sprague-Dawley , Transdução de Sinais/efeitos dos fármacos , Relação Estrutura-Atividade , Serina-Treonina Quinases TOR/metabolismoRESUMO
mTOR is part of the PI3K/AKT pathway and is a central regulator of cell growth and survival. Since many cancers display mutations linked to the mTOR signaling pathway, mTOR has emerged as an important target for oncology therapy. Herein, we report the discovery of triazine benzimidazole inhibitors that inhibit mTOR kinase activity with up to 200-fold selectivity over the structurally homologous kinase PI3Kα. When tested in a panel of cancer cell lines displaying various mutations, a selective inhibitor from this series inhibited cellular proliferation with a mean IC(50) of 0.41 µM. Lead compound 42 demonstrated up to 83% inhibition of mTOR substrate phosphorylation in a murine pharmacodynamic model.