RESUMEN
Marchiafava-Bignami disease (MBD) is a metabolic disease of the nervous system. It mainly involves the Corpus callosum, but the handknob area is rarely involved. This article reports a MBD case involving the bilateral handknob area. The involvement of the bilateral handknob area contributes to the clinical presentation of convulsions of both hands. Through this case, more clinicians realize the bilateral handknob area involvement in MBD, which is helpful for the identification and diagnosis of MBD. To our knowledge, this is the first report on MBD involving the bilateral handknob area.
Asunto(s)
Alcoholismo , Enfermedad de Marchiafava-Bignami , Humanos , Enfermedad de Marchiafava-Bignami/complicaciones , Enfermedad de Marchiafava-Bignami/diagnóstico por imagen , Imagen por Resonancia Magnética , Cuerpo Calloso/diagnóstico por imagenRESUMEN
JNK activity has been implicated in the malignant proliferation, invasion and drug-resistance of glioma cells (GCs), but the molecular mechanisms underlying JNK activation are currently unknown. Here, we reported that MKK7, not MKK4, directly activates JNK in GCs and exerts oncogenic effects on tumor formation. Notably, MKK7 expression in glioma tissues was closely correlated with the grade of the glioma and JNK/c-Jun activation. Mechanistically, MKK7 transcription critically depends on the complexes formed by HDAC4 and the transcriptional factors SP1 and Krüppel-like factor-5 (KLF5), wherein HDAC4 directly deacetylates both SP1 and KLF5 and synergistically upregulates MKK7 transcription through two SP1 sites located on its promoter. In contrast, the increases in acetylated-SP1 and acetylated-KLF5 after HDAC4 inhibition switched to transcriptionally suppress MKK7. Selective inhibition of HDAC4 by LMK235, siRNAs or blockage of SP1 and KLF5 by the ectopic dominant-negative SP1 greatly reduced the malignant capacity of GCs. Furthermore, suppression of both MKK7 expression and JNK/c-Jun activities was involved in the tumor-growth inhibitory effects induced by LMK235 in U87-xenograft mice. Interestingly, HDAC4 is highly expressed in glioma tissues, and the rate of HDAC4 nuclear import is closely correlated with glioma grade, as well as with MKK7 expression. Collectively, these findings demonstrated that highly expressed MKK7 contributes to JNK/c-Jun signaling-mediated glioma formation. MKK7 transcription, regulated by SP1 and KLF5, critically depends on HDAC4 activity, and inhibition of HDAC4 presents a potential strategy for suppressing the oncogenic roles of MKK7/JNK/c-Jun signaling in GCs.
Asunto(s)
Glioma/genética , Histona Desacetilasas/genética , Factores de Transcripción de Tipo Kruppel/genética , MAP Quinasa Quinasa 7/genética , Proteínas Represoras/genética , Factor de Transcripción Sp1/genética , Animales , Línea Celular Tumoral , Humanos , Proteínas Quinasas JNK Activadas por Mitógenos/genética , Sistema de Señalización de MAP Quinasas/genética , Masculino , Ratones , Ratones Endogámicos BALB C , Ratones Desnudos , Regiones Promotoras Genéticas/genética , Transcripción Genética/genética , Activación Transcripcional/genética , Regulación hacia Arriba/genéticaRESUMEN
OBJECTIVE: To examine the association between fragile X mental retardation protein (FMRP) expression and astrocytoma characteristics. METHODS: Pathologic grade and expressions of glial fibrillary acidic protein (GFAP), Ki67 (proliferation marker), and FMRP were determined in astrocytoma specimens from 74 patients. Kaplan-Meier survival analysis was undertaken. Pathologic grade and protein levels of FMRP were determined in 24 additional patients with astrocytoma and 6 controls (cerebral trauma). In cultured U251 and U87 cell lines, the effects of FMRP knock-down on cell proliferation, AKT/mTOR/GSK-3ß and MEK/ERK signaling were studied. The effects of FMRP knock-down on the volumes and weights of U251 cell-derived orthotopic tumors in mice were investigated. RESULTS: In patients, FMRP expression was increased in grade IV (5.1-fold, P<0.01) and grade III (3.2-fold, P<0.05) astrocytoma, compared with controls. FMRP and Ki67 expressions were positively correlated (R2=0.877, P<0.001). Up-regulation of FMRP was associated with poorer survival among patients with FMRP integrated optical density >30 (P<0.01). In astrocytoma cell lines, FMRP knock-down slowed proliferation (P<0.05), inhibited total MEK levels P<0.05, and reduced phosphorylation of MEK (Ser217/221) and ERK (Thr202/Tyr204) (P<0.05). In mice with orthotopic tumors, FMRP knock-down decreased FMRP and Ki67 expressions, and reduced tumor volume and weight (36.3% or 61.5% on day 15, both P<0.01). Also, phosphorylation of MEK (Ser217/221) and ERK (Thr202/Tyr204), and total MEK in xenografts were decreased in sh-FMRP xenografts compared with non-transfected ones (all P<0.05). CONCLUSION: Enhanced FMRP expression in astrocytoma may promote proliferation through activation of MEK/ERK signaling.