RESUMEN
Head and neck squamous cell carcinoma (HNSCC) represents a major health concern worldwide. We applied the matrix-assisted laser desorption/ionization (MALDI) imaging mass spectrometry (IMS) to analyze paired normal (N) and tumor (T) samples from head and neck squamous cell carcinoma as well as liquid chromatography with tandem mass spectrometry (LC-MS/MS) analysis in HNSCC cell lines to identify tumor-associated biomarkers. Our results showed a number of proteins found to be over-expressed in HNSCC. We identified thymosin beta-4 X-linked (TMSB4X) is one of the most significant candidate biomarkers. Higher TMSB4X expression in the tumor was found by N/T-paired HNSCC samples at both RNA and protein level. Overexpression of TMSB4X was found significantly associated with poor prognosis of overall survival (OS, P = 0.006) and recurrence-free survival (RFS, P = 0.013) in HNSCC patients. Silencing of TMSB4X expression in HNSCC cell line reduced the proliferation and invasion ability in vitro, as well as inhibited the cervical lymph node metastasis in vivo. Altogether, our global proteomics analysis identified that TMSB4X is a newly discovered biomarker in HNSCC whose functions resulted in enhanced proliferation and metastasis in vitro and in vivo. TMSB4X may be a potential therapeutic target for treating HNSCC patients.
Asunto(s)
Neoplasias de Cabeza y Cuello/patología , Proteómica/métodos , Carcinoma de Células Escamosas de Cabeza y Cuello/patología , Timosina/genética , Timosina/metabolismo , Regulación hacia Arriba , Anciano , Animales , Biomarcadores de Tumor/genética , Biomarcadores de Tumor/metabolismo , Línea Celular Tumoral , Proliferación Celular , Cromatografía Liquida , Femenino , Regulación Neoplásica de la Expresión Génica , Neoplasias de Cabeza y Cuello/genética , Neoplasias de Cabeza y Cuello/metabolismo , Humanos , Masculino , Ratones , Persona de Mediana Edad , Invasividad Neoplásica , Trasplante de Neoplasias , Pronóstico , Espectrometría de Masa por Láser de Matriz Asistida de Ionización Desorción , Carcinoma de Células Escamosas de Cabeza y Cuello/genética , Carcinoma de Células Escamosas de Cabeza y Cuello/metabolismo , Análisis de Supervivencia , Espectrometría de Masas en TándemRESUMEN
BACKGROUND: Neurons and astrocytes are generated from common neural precursors, yet neurogenesis precedes astrocyte formation during embryogenesis. The mechanisms of neural development underlying suppression and de-suppression of differentiation-related genes for cell fate specifications are not well understood. METHODOLOGY/PRINCIPAL FINDINGS: By using an in vitro system in which NTera-2 cells were induced to differentiate into an astrocyte-like lineage, we revealed a novel role for Sin3A in maintaining the suppression of GFAP in NTera-2 cells. Sin3A coupled with MeCP2 bound to the GFAP promoter and their occupancies were correlated with repression of GFAP transcription. The repression by Sin3A and MeCP2 may be an essential mechanism underlying the inhibition of cell differentiation. Upon commitment toward an astrocyte-like lineage, Sin3A- MeCP2 departed from the promoter and activated STAT3 simultaneously bound to the promoter and exon 1 of GFAP; meanwhile, olig2 was exported from nuclei to the cytoplasm. This suggested that a three-dimensional or higher-order structure was provoked by STAT3 binding between the promoter and proximal coding regions. STAT3 then recruited CBP/p300 to exon 1 and targeted the promoter for histone H3K9 and H3K14 acetylation. The CBP/p300-mediated histone modification further facilitates chromatin remodeling, thereby enhancing H3K4 trimethylation and recruitment of RNA polymerase II to activate GFAP gene transcription. CONCLUSIONS/SIGNIFICANCE: These results provide evidence that exchange of repressor and activator complexes and epigenetic modifications are critical strategies for cellular differentiation and lineage-specific gene expression.
Asunto(s)
Diferenciación Celular/fisiología , Cromatina/metabolismo , Proteína Ácida Fibrilar de la Glía/metabolismo , Factor de Transcripción STAT3/metabolismo , Animales , Factores de Transcripción con Motivo Hélice-Asa-Hélice Básico/metabolismo , Western Blotting , Ciclo Celular/genética , Ciclo Celular/fisiología , Diferenciación Celular/genética , Línea Celular , Núcleo Celular/metabolismo , Inmunoprecipitación de Cromatina , Metilación de ADN/genética , Metilación de ADN/fisiología , Proteína Ácida Fibrilar de la Glía/genética , Humanos , Inmunohistoquímica , Inmunoprecipitación , Lentivirus/genética , Proteína 2 de Unión a Metil-CpG/metabolismo , Ratones , Proteínas del Tejido Nervioso/metabolismo , Factor de Transcripción 2 de los Oligodendrocitos , Unión Proteica , Transporte de Proteínas/genética , Transporte de Proteínas/fisiología , Interferencia de ARN , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Factor de Transcripción STAT3/genéticaRESUMEN
The establishment and maintenance of epithelial polarity are crucial for tissue organization and function in mammals. Epithelial cadherin (E-cadherin) is expressed in epithelial cell membrane and is important for cell-cell adhesion, intercellular junctions formation, as well as epithelial cell polarization. We report herein that CAS (CAS/CSE 1), the human cellular apoptosis susceptibility protein, interacts with E-cadherin and stimulates polarization of HT-29 human colon epithelial cells. CAS binds with E-cadherin but not with beta-catenin in the immunoprecipitation assays. Interaction of CAS with E-cadherin enhances the formation of E-cadherin/beta-catenin cell-cell adhesive complex. Electron microscopic study demonstrated that CAS overexpression in cells stimulates intercellular junction complex formation. The disorganization of cellular cytoskeleton by cytochalasin D, colchicine, or acrylamide treatment disrupts CAS-stimulated HT-29 cell polarization. CAS-mediated HT-29 cell polarity is also inhibited by antisense E-cadherin DNA expression. Our results indicate that CAS cooperates with E-cadherin and plays a role in the establishment of epithelial cell polarity.