RESUMO
Mesenchymal-epithelial transition factor (MET) is a receptor tyrosine kinase that serves a critical function in numerous developmental, morphogenic, and proliferative signaling pathways. If dysregulated, MET has been shown to be involved in the development and survival of several cancers, including non-small cell lung cancer (NSCLC), renal cancer, and other epithelial tumors. Currently, the clinical efficacy of FDA approved MET inhibitors is limited by on-target acquired resistance, dose-limiting toxicities, and less than optimal efficacy against brain metastasis. Therefore, there is still an unmet medical need for the development of MET inhibitors to address these issues. Herein we report the application of structure-based design for the discovery and development of a novel class of brain-penetrant MET inhibitors with enhanced activity against clinically relevant mutations and improved selectivity. Compound 13 with a MET D1228N cell line IC50 value of 23 nM showed good efficacy in an intracranial tumor model and increased the median overall survival of the animals to 100% when dosed orally at 100 mg/kg daily for 21 days.
Assuntos
Antineoplásicos , Inibidores de Proteínas Quinases , Proteínas Proto-Oncogênicas c-met , Pirazóis , Proteínas Proto-Oncogênicas c-met/antagonistas & inibidores , Proteínas Proto-Oncogênicas c-met/metabolismo , Humanos , Animais , Inibidores de Proteínas Quinases/farmacologia , Inibidores de Proteínas Quinases/química , Inibidores de Proteínas Quinases/síntese química , Inibidores de Proteínas Quinases/uso terapêutico , Pirazóis/farmacologia , Pirazóis/química , Pirazóis/síntese química , Linhagem Celular Tumoral , Relação Estrutura-Atividade , Antineoplásicos/farmacologia , Antineoplásicos/química , Antineoplásicos/síntese química , Antineoplásicos/uso terapêutico , Descoberta de Drogas , Pirazinas/farmacologia , Pirazinas/síntese química , Pirazinas/química , Pirazinas/uso terapêutico , Neoplasias Encefálicas/tratamento farmacológico , Neoplasias Encefálicas/patologia , Camundongos , Mutação , RatosRESUMO
Prior biochemical analysis of the heterodimeric vaccinia virus mRNA capping enzyme suggests roles not only in mRNA capping but also in early viral gene transcription termination and intermediate viral gene transcription initiation. Prior phenotypic characterization of Dts36, a temperature sensitive virus mutant affecting the large subunit of the capping enzyme was consistent with the multifunctional roles of the capping enzyme in vivo. We report a biochemical analysis of the capping enzyme encoded by Dts36. Of the three enzymatic activities required for mRNA capping, the guanylyltransferase and methyltransferase activities are compromised while the triphosphatase activity and the D12 subunit interaction are unaffected. The mutant enzyme is also defective in stimulating early gene transcription termination and intermediate gene transcription initiation in vitro. These results confirm that the vaccinia virus mRNA capping enzyme functions not only in mRNA capping but also early gene transcription termination and intermediate gene transcription initiation in vivo.