RESUMO
We describe a novel series of potent inhibitors of the kinase activity of mTOR. The compounds display good selectivity relative to other PI3K-related kinase family members and, in cellular assays, inhibit both mTORC1 and mTORC2 complexes and exhibit good antiproliferative activity.
Assuntos
Antineoplásicos/química , Diaminas/química , Morfolinas/química , Inibidores de Proteínas Quinases/química , Proteínas Quinases/química , Pirimidinas/química , Antineoplásicos/síntese química , Antineoplásicos/farmacologia , Linhagem Celular , Diaminas/síntese química , Diaminas/farmacologia , Descoberta de Drogas , Humanos , Alvo Mecanístico do Complexo 1 de Rapamicina , Morfolinas/síntese química , Morfolinas/farmacologia , Complexos Multiproteicos , Inibidores de Proteínas Quinases/síntese química , Inibidores de Proteínas Quinases/farmacologia , Proteínas Quinases/metabolismo , Proteínas , Pirimidinas/síntese química , Pirimidinas/farmacologia , Relação Estrutura-Atividade , Serina-Treonina Quinases TOR , Fatores de Transcrição/antagonistas & inibidores , Fatores de Transcrição/metabolismoRESUMO
The mammalian target of rapamycin (mTOR) kinase forms two multiprotein complexes, mTORC1 and mTORC2, which regulate cell growth, cell survival, and autophagy. Allosteric inhibitors of mTORC1, such as rapamycin, have been extensively used to study tumor cell growth, proliferation, and autophagy but have shown only limited clinical utility. Here, we describe AZD8055, a novel ATP-competitive inhibitor of mTOR kinase activity, with an IC50 of 0.8 nmol/L. AZD8055 showed excellent selectivity (approximately 1,000-fold) against all class I phosphatidylinositol 3-kinase (PI3K) isoforms and other members of the PI3K-like kinase family. Furthermore, there was no significant activity against a panel of 260 kinases at concentrations up to 10 micromol/L. AZD8055 inhibits the phosphorylation of mTORC1 substrates p70S6K and 4E-BP1 as well as phosphorylation of the mTORC2 substrate AKT and downstream proteins. The rapamycin-resistant T37/46 phosphorylation sites on 4E-BP1 were fully inhibited by AZD8055, resulting in significant inhibition of cap-dependent translation. In vitro, AZD8055 potently inhibits proliferation and induces autophagy in H838 and A549 cells. In vivo, AZD8055 induces a dose-dependent pharmacodynamic effect on phosphorylated S6 and phosphorylated AKT at plasma concentrations leading to tumor growth inhibition. Notably, AZD8055 results in significant growth inhibition and/or regression in xenografts, representing a broad range of human tumor types. AZD8055 is currently in phase I clinical trials.