RESUMEN
Inhibitors of Bruton's tyrosine kinase (BTK) possess much promise for the treatment of oncologic and autoimmune indications. However, our current knowledge of the role of BTK in immune competence has been gathered in the context of genetic inactivation of btk in both mice and man. Using the novel BTK inhibitor PF-303, we model the clinical phenotype of BTK inhibition by systematically examining the impact of PF-303 on the mature immune system in mice. We implicate BTK in tonic BCR signaling, demonstrate dependence of the T3 B cell subset and IgM surface expression on BTK activity, and find that B1 cells survive and function independently of BTK. Although BTK inhibition does not impact humoral memory survival, Ag-driven clonal expansion of memory B cells and Ab-secreting cell generation are inhibited. These data define the role of BTK in the mature immune system and mechanistically predict the clinical phenotype of chronic BTK inhibition.
Asunto(s)
Subgrupos de Linfocitos B/inmunología , Inmunidad Humoral/fisiología , Memoria Inmunológica/fisiología , Modelos Inmunológicos , Proteínas Tirosina Quinasas/inmunología , Agammaglobulinemia Tirosina Quinasa , Animales , Supervivencia Celular/efectos de los fármacos , Supervivencia Celular/genética , Supervivencia Celular/inmunología , Humanos , Inmunoglobulina M/genética , Inmunoglobulina M/inmunología , Ratones , Ratones Endogámicos CBA , Ratones Noqueados , Inhibidores de Proteínas Quinasas/farmacología , Proteínas Tirosina Quinasas/antagonistas & inhibidores , Proteínas Tirosina Quinasas/genéticaRESUMEN
The two specialized C. elegans distal tip cells (DTCs) provide an in vivo model system for the study of developmentally regulated cell migration. We identified cacn-1/cactin, a well-conserved, novel regulator of cell migration in a genome-wide RNAi screen for regulators of DTC migration. RNAi depletion experiments and analysis of the hypomorphic allele cacn-1(tm3126) indicate that CACN-1 is required during DTC migration for proper pathfinding and for cessation of DTC migration at the end of larval morphogenesis. Strong expression of CACN-1 in the DTCs, and data from cell-specific RNAi depletion experiments, suggest that CACN-1 is required cell-autonomously to control DTC migration. Importantly, genetic interaction data with Rac GTPase activators and effectors suggest that CACN-1 acts specifically to inhibit the mig-2/Rac pathway, and in parallel to ced-10/Rac, to control DTC pathfinding.
Asunto(s)
Proteínas de Caenorhabditis elegans/metabolismo , Caenorhabditis elegans/citología , Proteínas Portadoras/metabolismo , Movimiento Celular , Proteínas de Drosophila/metabolismo , Proteínas de Unión al GTP rac/metabolismo , Animales , Caenorhabditis elegans/embriología , Proteínas de Caenorhabditis elegans/genética , Proteínas Portadoras/genética , Proteínas de Drosophila/genética , Gónadas/embriología , Proteínas de Unión al GTP rac/genéticaRESUMEN
Using a functional approach to investigate the epigenetics of type 2 diabetes (T2D), we combine three lines of evidence-diet-induced epigenetic dysregulation in mouse, epigenetic conservation in humans, and T2D clinical risk evidence-to identify genes implicated in T2D pathogenesis through epigenetic mechanisms related to obesity. Beginning with dietary manipulation of genetically homogeneous mice, we identify differentially DNA-methylated genomic regions. We then replicate these results in adipose samples from lean and obese patients pre- and post-Roux-en-Y gastric bypass, identifying regions where both the location and direction of methylation change are conserved. These regions overlap with 27 genetic T2D risk loci, only one of which was deemed significant by GWAS alone. Functional analysis of genes associated with these regions revealed four genes with roles in insulin resistance, demonstrating the potential general utility of this approach for complementing conventional human genetic studies by integrating cross-species epigenomics and clinical genetic risk.
Asunto(s)
Diabetes Mellitus Tipo 2/genética , Epigénesis Genética , Adipocitos/citología , Adipocitos/metabolismo , Animales , Células Cultivadas , Metilación de ADN , Diabetes Mellitus Tipo 2/patología , Dieta Alta en Grasa , Regulación de la Expresión Génica , Sitios Genéticos , Estudio de Asociación del Genoma Completo , Prueba de Tolerancia a la Glucosa , Humanos , Masculino , Ratones , Ratones Endogámicos C57BL , Polimorfismo de Nucleótido Simple , ARN Interferente Pequeño/metabolismo , Proteína 2 Similar al Factor de Transcripción 7/genéticaRESUMEN
Hsp90 facilitates the maturation and stability of numerous oncoproteins, including HER2. The aim of this study was to assess the antitumor activity of the Hsp90 inhibitor IPI-504 in trastuzumab-resistant, HER2-overexpressing breast cancer cells. Therapy with trastuzumab, IPI-504, and the combination of trastuzumab and IPI-504 was evaluated in trastuzumab-sensitive and trastuzumab-resistant cells. Inhibition of protein targets, cell proliferation, and tumor growth was assessed in vitro and in xenograft models. IPI-504 inhibited proliferation of both trastuzumab-sensitive and trastuzumab-resistant cells. Administration of IPI-504 markedly reduced total levels of HER2 and Akt, as well as phosphorylated Akt and mitogen-activated protein kinase (MAPK), to an equal extent in trastuzumab-sensitive and trastuzumab-resistant cells. IPI-504, used as single agent or in combination with trastuzumab, also inhibited in vivo the growth of both trastuzumab-sensitive and -resistant tumor xenografts. As a mechanism for the observed antitumor activity, IPI-504 resulted in a marked decrease in the levels of HER2, Akt, p-Akt, and p-MAPK in trastuzumab-resistant xenografts as early as 12 hours after a single dose of IPI-504. IPI-504-mediated Hsp90 inhibition may represent a novel therapeutic approach in trastuzumab refractory HER2-positive breast cancer.