RESUMEN
DAB2IP has been identified as a tumor suppressor in several cancers but its oncogenic role and transcriptionally regulatory mechanisms in the progression of colorectal carcinoma (CRC) remain unknown. In this study, DAB2IP was down-regulated in CRC tissues and a valuable prognostic marker for survival of CRC patients, especially in the late stage. Moreover, DAB2IP was sufficient to suppress proliferation, epithelial-mesenchymal transition (EMT), invasion and metastasis in CRC. Mechanically, the linear complex of EZH2/HDAC1/Snail contributed to DAB2IP silencing in CRC cells. The study further proved that the positive feedback loop between Snail and DAB2IP existed in CRC cells and DAB2IP was required for Snail-induced aggressive cell behaviors. Finally, DAB2IP correlated negatively with Snail and EZH2 expressions in CRC tissues. Our findings reveal the suppressive role and a novel regulatory mechanism of DAB2IP expression in the progression of CRC. DAB2IP may be a potential, novel therapeutic and prognostic target for clinical CRC patients.
Asunto(s)
Carcinoma/metabolismo , Neoplasias Colorrectales/metabolismo , Transición Epitelial-Mesenquimal , Factores de Transcripción/metabolismo , Proteínas Activadoras de ras GTPasa/metabolismo , Animales , Células CACO-2 , Línea Celular Tumoral , Proliferación Celular , Regulación Neoplásica de la Expresión Génica , Silenciador del Gen , Células HCT116 , Células HT29 , Humanos , Inmunoprecipitación , Ratones , Ratones Desnudos , Invasividad Neoplásica , Metástasis de la Neoplasia , Pronóstico , Factores de Transcripción de la Familia SnailRESUMEN
Colorectal cancer (CRC) is one of the most common malignancies. Increasing evidences indicate that dysregulation of miRNAs is a frequent event in CRC and contributes to the pathogenesis of CRC. In this study, we found that over-expression of miR-34a inhibited cell proliferation and invasion, induced a cell cycle arrest and triggered apoptosis, while knockdown of miR-34a showed the opposite effects. Moreover, ectopic miR-34a suppressed tumor growth and metastasis of CRC cells in vivo. FMNL2 and E2F5 were identified as direct targets of miR-34a. Reintroduction of FMNL2 or E2F5 without 3'UTR region reversed the inhibitory effects of miR-34a on cell proliferation and invasion. MiR-34a was down-regulated in CRC cells and inversely correlated with FMNL2 and E2F5 expressions. Our study suggests that miR-34a is an important tumor suppressor of CRC progression by targeting FMNL2 and E2F5, thus providing new insight into the molecular mechanisms underlying CRC progression and establishing a strong potential for the application of miR-34a as a novel therapeutic marker against CRC.
Asunto(s)
Neoplasias Colorrectales/genética , Factor de Transcripción E2F5/metabolismo , Regulación Neoplásica de la Expresión Génica , MicroARNs/metabolismo , Proteínas/metabolismo , Regiones no Traducidas 3' , Apoptosis/genética , Puntos de Control del Ciclo Celular , Línea Celular Tumoral , Proliferación Celular/genética , Neoplasias Colorrectales/patología , Progresión de la Enfermedad , Regulación hacia Abajo , Factor de Transcripción E2F5/genética , Forminas , Genes Supresores de Tumor , Células HCT116 , Células HT29 , Humanos , MicroARNs/genética , Proteínas/genéticaRESUMEN
As a transcriptional repressor, forkhead box D3 (FOXD3) plays an important role in tumorigenesis and progression of several tumors. However, the function and methylation status of FOXD3 remain unknown in the progression of hepatocellular carcinoma (HCC). In this study, we found that FOXD3 was decreased in HCC tissues and correlated with differentiation, AFP and poor survival of HCC patients (p<0.05). Down-regulation of FOXD3 in HCC tissues was mainly due to promoter hypermethylation. In vitro and in vivo functional results showed that ectopic FOXD3 inhibited the proliferation, migration, epithelial-mesenchymal transition (EMT) and invasion in HepG2 and SMMC-7721 cells, and FOXD3 depletion in HepG2 and QGY-7701 cells showed the adverse effects (p<0.05). Moreover, FOXD3 was sufficient to suppress tumor growth and pulmonary metastatic potential in mice. Our findings suggest that down-regulation of FOXD3, due to promoter hypermethylation plays an important role in the progression of HCC and may be a promising prognostic biomarker for HCC patients.
Asunto(s)
Carcinoma Hepatocelular/genética , Carcinoma Hepatocelular/secundario , Movimiento Celular , Proliferación Celular , Metilación de ADN , Factores de Transcripción Forkhead/genética , Neoplasias Hepáticas/genética , Neoplasias Hepáticas/patología , Adulto , Anciano , Anciano de 80 o más Años , Animales , Apoptosis , Biomarcadores de Tumor/genética , Biomarcadores de Tumor/metabolismo , Western Blotting , Carcinoma Hepatocelular/mortalidad , Femenino , Técnica del Anticuerpo Fluorescente , Estudios de Seguimiento , Factores de Transcripción Forkhead/metabolismo , Regulación Neoplásica de la Expresión Génica , Humanos , Técnicas para Inmunoenzimas , Neoplasias Hepáticas/mortalidad , Masculino , Ratones , Ratones Desnudos , Persona de Mediana Edad , Invasividad Neoplásica , Estadificación de Neoplasias , Pronóstico , Regiones Promotoras Genéticas , ARN Mensajero/genética , Reacción en Cadena en Tiempo Real de la Polimerasa , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Tasa de Supervivencia , Células Tumorales Cultivadas , Ensayos Antitumor por Modelo de XenoinjertoRESUMEN
F-box only protein 8 (FBX8), a novel component of F-box proteins, has recently been observed in several malignancies. However, its clinical implication in the progression of gastric cancer still remains unclear. The aim of this study was to explore the role of FBX8 in gastric cancer (GC) and analyze its correlation with tumor progression and prognosis. The expression of FBX8 in GC cell lines and matched pairs of fresh gastric cancer tissues were detected by real-time RT-PCR and Western blotting. Immunohistochemistry was used to analyze clinicopathological patterns of FBX8 in 136 cases of clinical paraffin-embedded GC tissues. A series of functional assays were conducted to evaluate the effect of FBX8 on proliferation and invasion in vitro and metastasis in vivo. FBX8 was markedly down-regulated in GC tissues compared to adjacent normal tissues. Patients with low FBX8 had shorter overall survival time and poor prognosis. Knocking down FBX8 obviously promoted proliferation and invasion in BGC823 cells, while over-expression of FBX8 in SGC7901 and AGS cells had the opposite effects. Moreover, FBX8 was sufficient to suppress metastasis in nude mice. Down-regulation of FBX8 significantly correlates with invasion, metastasis and poor survival time in GC patients. FBX8 may serve as a promising therapeutic target for inhibition of GC metastasis.
Asunto(s)
Proteínas F-Box/genética , Neoplasias Gástricas/genética , Animales , Línea Celular Tumoral , Proliferación Celular , Células Cultivadas , Regulación hacia Abajo , Proteínas F-Box/metabolismo , Femenino , Humanos , Masculino , Ratones , Ratones Desnudos , Ratones SCID , Persona de Mediana Edad , Invasividad Neoplásica , Metástasis de la Neoplasia , Pronóstico , Neoplasias Gástricas/diagnóstico , Neoplasias Gástricas/patologíaRESUMEN
Mesangial cells (MCs) proliferation and accumulation of glomerular matrix proteins such as fibronectin (FN) are the early features of diabetic nephropathy, with MCs known to upregulate matrix protein synthesis in response to high glucose. Recently, it has been found that andrographolide has renoprotective effects on diabetic nephropathy. However, the molecular mechanism underlying these effects remains unclear. Cell viability and proliferation was evaluated by MTT. FN expression was examined by immunofluorescence and immunoblotting. Activator protein-1 (AP-1) activation was assessed by immunoblotting, luciferase reporter and electrophoretic mobility shift assays. Andrographolide significantly decreased high glucose-induced cell proliferation and FN expression in MCs. Exposure of MCs to high glucose markedly stimulated the expression of phosphorylated c-jun, whereas the stimulation was inhibited by andrographolide. Plasmid pAP-1-Luc luciferase reporter assay showed that andrographolide blocked high glucose-induced AP-1 transcriptional activity. EMSA assay demonstrated that increased AP-1 binding to an AP-1 binding site at -1,029 in the FN gene promoter upon high glucose stimulation, and the binding were disrupted by andrographolide treatment. These data indicate that andrographolide suppresses high glucose-induced FN expression by inhibiting AP-1-mediated pathway.