RESUMEN

Familial Dysautonomia (FD) is an autosomal recessive disorder caused by a splice site mutation in the gene ELP1, which disproportionally affects neurons. While classically characterized by deficits in sensory and autonomic neurons, neuronal defects in the central nervous system have also been described. Although ELP1 expression remains high in the normal developing and adult cerebellum, its role in cerebellar development is unknown. To explore the role of Elp1 in the cerebellum, we knocked out Elp1 in cerebellar granule cell progenitors (GCPs) and examined the outcome on animal behavior and cellular composition. We found that GCP-specific conditional knockout of Elp1 (Elp1cKO) resulted in ataxia by 8 weeks of age. Cellular characterization showed that the animals had smaller cerebella with fewer granule cells. This defect was already apparent as early as 7 days after birth, when Elp1cKO animals also had fewer mitotic GCPs and shorter Purkinje dendrites. Through molecular characterization, we found that loss of Elp1 was associated with an increase in apoptotic cell death and cell stress pathways in GCPs. Our study demonstrates the importance of ELP1 in the developing cerebellum, and suggests that loss of Elp1 in the GC lineage may also play a role in the progressive ataxia phenotypes of FD patients.

Asunto(s)

Cerebelo , Disautonomía Familiar , Ratones Noqueados , Fenotipo , Animales , Disautonomía Familiar/genética , Disautonomía Familiar/patología , Cerebelo/metabolismo , Cerebelo/patología , Ratones , Modelos Animales de Enfermedad , Ataxia/genética , Ataxia/patología , Ataxia/metabolismo , Células-Madre Neurales/metabolismo , Apoptosis/fisiología , Péptidos y Proteínas de Señalización Intracelular

RESUMEN

Medulloblastoma is a highly aggressive pediatric brain tumor, in which sporadic expression of the pluripotency factor OCT4 has been recently correlated with poor patient survival. However the contribution of specific OCT4 isoforms to tumor aggressiveness is still poorly understood. Here, we report that medulloblastoma cells stably overexpressing the OCT4A isoform displayed enhanced clonogenic, tumorsphere generation, and invasion capabilities. Moreover, in an orthotopic metastatic model of medulloblastoma, OCT4A overexpressing cells generated more developed, aggressive and infiltrative tumors, with tumor-bearing mice attaining advanced metastatic disease and shorter survival rates. Pro-oncogenic OCT4A effects were expression-level dependent and accompanied by distinct chromosomal aberrations. OCT4A overexpression in medulloblastoma cells also induced a marked differential expression of non-coding RNAs, including poorly characterized long non-coding RNAs and small nucleolar RNAs. Altogether, our findings support the relevance of pluripotency-related factors in the aggravation of medulloblastoma traits classically associated with poor clinical outcome, and underscore the prognostic and therapeutic value of OCT4A in this challenging type of pediatric brain cancer.

Asunto(s)

Biomarcadores de Tumor/metabolismo , Neoplasias Encefálicas/secundario , Neoplasias Cerebelosas/patología , Meduloblastoma/patología , Factor 3 de Transcripción de Unión a Octámeros/metabolismo , Animales , Apoptosis , Biomarcadores de Tumor/genética , Neoplasias Encefálicas/genética , Neoplasias Encefálicas/metabolismo , Movimiento Celular , Proliferación Celular , Neoplasias Cerebelosas/genética , Neoplasias Cerebelosas/metabolismo , Femenino , Humanos , Meduloblastoma/genética , Meduloblastoma/metabolismo , Ratones , Ratones Endogámicos BALB C , Ratones Desnudos , Factor 3 de Transcripción de Unión a Octámeros/genética , Pronóstico , Células Tumorales Cultivadas , Ensayos Antitumor por Modelo de Xenoinjerto

RESUMEN

Soybean isoflavonoids have received significant attention due to their potential anticarcinogenic and antiproliferative effects and possible role in many signal transduction pathways. However, their mechanisms of action and their molecular targets remain to be further elucidated. In this paper, we demonstrated that two soybean isoflavones (genistein and daidzein) reduced the proliferation of the human colon adenocarcinoma grade II cell line (HT-29) at concentrations of 25 and 50-100 µM, respectively. We then investigated the effects of genistein and daidzein by RT-PCR on molecules that involved in tumor development and progression by their regulation of cell proliferation. At a concentration of 50 µM genistein, there was suppressed expression of ß-catenin (CTNNBIP1). Neither genistein nor daidzein affected APC (adenomatous polyposis coli) or survivin (BIRC5) expression when cells were treated with concentrations of 10 or 50 µM. These data suggest that the down-regulation of ß-catenin by genistein may constitute an important determinant of the suppression of HT-29 cell growth and may be exploited for the prevention and treatment of colon cancer.

Asunto(s)

Adenocarcinoma/genética , Adenocarcinoma/patología , Proteína de la Poliposis Adenomatosa del Colon/genética , Anticarcinógenos/farmacología , Procesos de Crecimiento Celular/efectos de los fármacos , Procesos de Crecimiento Celular/genética , Neoplasias del Colon/genética , Neoplasias del Colon/patología , Expresión Génica/efectos de los fármacos , Genisteína/farmacología , Proteínas Inhibidoras de la Apoptosis/genética , Péptidos y Proteínas de Señalización Intracelular/genética , Isoflavonas/farmacología , Fitoestrógenos/farmacología , Proteínas Adaptadoras Transductoras de Señales , Proteína de la Poliposis Adenomatosa del Colon/metabolismo , Proteína de la Poliposis Adenomatosa del Colon/fisiología , Anticarcinógenos/uso terapéutico , Relación Dosis-Respuesta a Droga , Expresión Génica/genética , Genisteína/uso terapéutico , Células HT29 , Humanos , Proteínas Inhibidoras de la Apoptosis/metabolismo , Proteínas Inhibidoras de la Apoptosis/fisiología , Péptidos y Proteínas de Señalización Intracelular/metabolismo , Péptidos y Proteínas de Señalización Intracelular/fisiología , Isoflavonas/uso terapéutico , Fitoestrógenos/uso terapéutico , Fitoterapia , Glycine max , Survivin

RESUMEN

Isoflavones are phenolic compounds widely distributed in plants and found in a high percentage in soybeans. They have important biological properties and are regarded as potential chemopreventive agents. The aim of this study was to verify the preventive effect of two soy isoflavones (genistein and daidzein) by a micronucleus assay, analysis of GST activity, and real-time RT-PCR analysis of GSTa2 gene expression. Mutagens of direct (doxorubicin) and indirect (2-aminoanthracene) DNA damage were used. Hepatoma cells (HTC) were treated with genistein or daidzein for 26 h at noncytotoxic concentrations; 10 µM when alone, and 0.1, 1.0 and 10 µM when combined with genotoxic agents. The micronucleus test demonstrated that both isoflavones alone had no genotoxic effect. Genistein showed antimutagenic effects at 10 µM with both direct and indirect DNA damage agents. On phase II enzyme regulation, the current study indicated an increase in total cytoplasmic GST activity in response to genistein and daidzein at 10 µM supplementation. However, the mRNA levels of GSTa2 isozymes were not differentially modulated by genistein or daidzein. The results point to an in vitro antimutagenic activity of genistein against direct and indirect DNA damage-induced mutagenicity.