RESUMEN
In highly polarized cells such as neurons, compartmentalization of mRNA and of local protein synthesis enables remarkably fast, precise, and local responses to external stimuli. These responses are highly important for neuron growth cone guidance, synapse formation, and regeneration following injury. Because an altered spatial distribution of mRNA can result in mental retardation or neurodegenerative diseases, subcellular transcriptome analysis of neurons could be a useful tool for studying these conditions, but current techniques, such as in situ hybridization, bulk microarray, and RNA-Seq, impose tradeoffs between spatial resolution and multiplexing. To obtain a comprehensive analysis of the cell body versus neurite transcriptome from the same neuron, we have recently developed a label-free, single-cell nanobiopsy platform based on scanning ion conductance microscopy that uses electrowetting within a quartz nanopipette to extract cellular material from living cells with minimal disruption of the cellular membrane and milieu. In this study, we used this platform to collect samples from the cell bodies and neurites of human neurons and analyzed the mRNA pool with multiplex RNA sequencing. The minute volume of a nanobiopsy sample allowed us to extract samples from several locations in the same cell and to map the various mRNA species to specific subcellular locations. In addition to previously identified transcripts, we discovered new sets of mRNAs localizing to neurites, including nuclear genes such as Eomes and Hmgb3 In summary, our single-neuron nanobiopsy analysis provides opportunities to improve our understanding of intracellular mRNA transport and local protein composition in neuronal growth, connectivity, and function.
Asunto(s)
Perfilación de la Expresión Génica , Células Madre Pluripotentes Inducidas/metabolismo , Neuritas/metabolismo , Enfermedades Neurodegenerativas/metabolismo , Análisis de Secuencia por Matrices de Oligonucleótidos , ARN Mensajero/biosíntesis , Análisis de Secuencia de ARN , Biopsia/métodos , Proteína HMGB3/biosíntesis , Proteína HMGB3/genética , Humanos , Células Madre Pluripotentes Inducidas/patología , Neuritas/patología , Enfermedades Neurodegenerativas/genética , Enfermedades Neurodegenerativas/patología , Proteínas de Dominio T Box/biosíntesis , Proteínas de Dominio T Box/genéticaRESUMEN
Our recent determination of a microRNA (miRNA) expression signature in prostate cancer (PCa) revealed that miR-205-5p was significantly reduced in PCa tissues and that it acted as an antitumor miRNA. The aim of this study was to identify oncogenic genes and pathways in PCa cells that were regulated by antitumor miR-205-5p. Genome-wide gene expression analyses and in silico miRNA database searches showed that 37 genes were putative targets of miR-205-5p regulation. Among those genes, elevated expression levels of seven in particular (HMGB3, SPARC, MKI67, CENPF, CDK1, RHOU, and POLR2D) were associated with a shorter disease-free survival in a large number of patients in the The Cancer Genome Atlas (TCGA) database. We focused on high-mobility group box 3 (HMGB3) because it was the most downregulated by ectopic expression of miR-205-5p in PC3 cells and its expression was involved in PCa pathogenesis. Luciferase reporter assays showed that HMGB3 was directly regulated by miR-205-5p in PCa cells. Knockdown studies using si-HMGB3 showed that expression of HMGB3 enhanced PCa cell aggressiveness. Overexpression of HMGB3/HMGB3 was confirmed in naive PCa and castration-resistant PCa (CRPC) clinical specimens. Novel approaches to analysis of antitumor miRNA-regulated RNA networks in PCa cells may provide new insights into the pathogenic mechanisms of the disease.
Asunto(s)
Genes Supresores de Tumor , Proteína HMGB3/biosíntesis , MicroARNs/biosíntesis , Proteínas de Neoplasias/biosíntesis , Neoplasias de la Próstata Resistentes a la Castración , ARN Neoplásico/biosíntesis , Línea Celular Tumoral , Proteína HMGB3/genética , Humanos , Masculino , MicroARNs/genética , Proteínas de Neoplasias/genética , Neoplasias de la Próstata Resistentes a la Castración/genética , Neoplasias de la Próstata Resistentes a la Castración/metabolismo , Neoplasias de la Próstata Resistentes a la Castración/patología , ARN Neoplásico/genéticaRESUMEN
HMGB3, an X-linked member of the high-mobility group (HMG) superfamily of HMG proteins, has been shown to affect numerous tumorigenic progression. However, the expression and the prognostic role of HMGB3 in esophageal squamous cell carcinoma (ESCC) remained unknown. In this study, we examined the HMGB3 expression in ESCC tissues and adjacent nontumorous tissues by qRT-PCR and immuohistochemistry. Statistical analyses were applied to test for prognostic and diagnostic associations. The mRNA levels of HMGB3 were found to be significantly higher in tumorous tissues than in the adjacent normal tissues. We found that the HMGB3 expression was higher in tumorous tissues than in the adjacent non-tumorous tissues by immunohistochemical analysis of paired tissue specimens (P < 0.001). Moreover, there was a significant correlation between HMGB3 expression and gender (P = 0.037), clinical stage (P = 0.038), T classification (P = 0.013) and N classification (P = 0.017). Patients with higher HMGB3 expression had shorter overall survival than those with lower HMGB3 expression. Multivariate Cox analysis indicated that HMGB3 expression is an independent prognostic factor for overall survival (HR = 0.591, 95% CI = 0.379-0.793, P = 0.039). In summary, these findings demonstrate that HMBG3 may be a potential molecular marker for predicting the prognosis of ESCC patients.
Asunto(s)
Biomarcadores de Tumor/análisis , Carcinoma de Células Escamosas/patología , Neoplasias Esofágicas/patología , Proteína HMGB3/biosíntesis , Adulto , Anciano , Anciano de 80 o más Años , Carcinoma de Células Escamosas/metabolismo , Carcinoma de Células Escamosas/mortalidad , Neoplasias Esofágicas/metabolismo , Neoplasias Esofágicas/mortalidad , Carcinoma de Células Escamosas de Esófago , Femenino , Humanos , Inmunohistoquímica , Estimación de Kaplan-Meier , Masculino , Persona de Mediana Edad , Pronóstico , Modelos de Riesgos Proporcionales , Reacción en Cadena en Tiempo Real de la Polimerasa , Regulación hacia ArribaRESUMEN
Human urinary bladder cancer (UBC) is the fourth most common cancer and the eighth most common cause of cancer death in the USA. High mobility group box 3 (HMGB3), a member of a family of proteins containing one or more high mobility group DNA binding motifs, was reported to be overexpressed in a variety of human cancers. However, the expression and role of HMGB3 in human UBC remains unclear. Here, we found that UBC patients had upregulated HMGB at both mRNA and protein levels. Immunochemistry (IHC) evaluation of HMGB3 expression in 113 UBC clinical specimens showed that high expression of HMGB3 had positive correlation with UBC tumor size (P = 0.019), tumor WHO grade (P = 0.031), stage (P = 0.028), and lymph node metastasis (P = 0.017). Moreover, patients with higher HMGB3 expression showed a poorer overall survival rate than those with relatively low HMGB3 (P = 0.0079, log-rank test). Multivariate analysis revealed that HMGB3 expression is an independent prognostic marker. The UBC cancer cell proliferation and migration ability were measured by 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide (MTT) and wound healing assays, respectively. RNA interference of HMGB3 in UBC cell lines inhibited cancer cell growth and migration, along with the downregulation of PCNA and MMP2 protein levels. In sum, our data suggests HMGB3 may serve as an important oncoprotein and indicate that overexpression of HMGB3 in UBC could be used as a potential prognostic marker.
Asunto(s)
Biomarcadores de Tumor/biosíntesis , Proliferación Celular/genética , Proteína HMGB3/biosíntesis , Neoplasias de la Vejiga Urinaria/genética , Anciano , Anciano de 80 o más Años , Biomarcadores de Tumor/genética , Femenino , Regulación Neoplásica de la Expresión Génica , Proteína HMGB3/genética , Humanos , Estimación de Kaplan-Meier , Metástasis Linfática , Masculino , Persona de Mediana Edad , Estadificación de Neoplasias , Pronóstico , Neoplasias de la Vejiga Urinaria/patologíaRESUMEN
Chromosomal rearrangements of the HMGA2 locus belong to the most common aberrations in human benign tumors. HMGA2 rearrangements often result in chimeric genes expressing transcripts consisting of the first three exons of HMGA2 followed by ectopic sequences derived from intron 3 of that gene. RT-PCR-based expression studies of 4 of these HMGA2 transcripts revealed a co-expression with the "wild-type" HMGA2a in tumor samples as well as in normal tissues. Northern blot hybridizations of the lipoma cell line Li-14 revealed the expression of five additional HMGA2 transcripts consisting of exons 1 to 3 but not exons 4 to 5 besides the full-length HMGA2a transcript. In silico analyses have been performed showing a high homology to well-established consensus sequences for the 3' splice acceptor site, the branch site, and poly(A) signal. Thus, it is quite obvious that the HMGA2 transcripts described herein are alternative, not aberrant, splice-products of the HMGA2 gene. It is hypothesized that HMGA2-dependent tumorigenesis is caused by a disturbed equilibrium in the co-expression of the HMGA2 splice variants leading to aberrant cell proliferation and/or malignant transformation of cells.
Asunto(s)
Empalme Alternativo , Transformación Celular Neoplásica/genética , Regulación Neoplásica de la Expresión Génica , Proteína HMGB3/genética , Intrones/genética , Neoplasias/genética , Proliferación Celular , Transformación Celular Neoplásica/metabolismo , Aberraciones Cromosómicas , Proteína HMGB3/biosíntesis , Células HeLa , Humanos , Neoplasias/metabolismo , Sitios de Carácter Cuantitativo/genética , Sitios de Empalme de ARN/genéticaRESUMEN
Hmgb3 is a member of a family of chromatin-binding proteins that can alter DNA structure to facilitate transcription factor binding. We identified the Hmgb3 cDNA in a subtractive hybridization screen for transcripts that are preferentially expressed in hematopoietic stem cells. We inserted an internal ribosomal entry site-green fluorescence protein cassette into the 3' untranslated region of the X-linked Hmgb3 locus to identify Hmgb3-expressing cells. In adult mice, Hmgb3 mRNA is detected in bone marrow cells, primitive Lin-, c-kit+, Sca-1+, IL-7Ralpha- cells, and Ter119+ erythroid cells. We observed that long-term repopulating ability is entirely contained in the subpopulation of Lin-, c-kitHI cells that express Hmgb3. Most common lymphoid and myeloid progenitors express Hmgb3. Introduction of a retrovirus containing the Hmgb3 cDNA into mouse bone marrow stem cells demonstrated that enforced expression of Hmgb3 inhibited B-cell and myeloid differentiation. We conclude that down-regulation of Hmgb3 protein levels is an important step for myeloid and B-cell differentiation.