RESUMEN
The myc oncogenes are frequently activated in human tumors, but there is no comprehensive insight into the target genes and downstream cellular pathways of these transcription factors. We applied serial analysis of gene expression (SAGE) to identify targets of N-myc in neuroblastomas. Analysis of 42,000 mRNA transcript tags in SAGE libraries of N-myc- transfected and control neuroblastoma cells revealed 114 up-regulated genes. The majority of these genes have a role in ribosome assembly and activity. Northern blot analysis confirmed up-regulation of all tested transcripts. Induction was complete within 4 h after N-myc expression. The large majority of the ribosomal proteins were induced, as well as genes controlling rRNA maturation. Cellular rRNA content was 45% induced. SAGE libraries and northern blot analysis confirmed up-regulation of many of these genes in N-myc-amplified neuroblastomas. As N-myc can functionally replace c-myc, we analyzed whether N-myc targets were induced by c-myc as well. Approximately 40% of these N-myc targets were up-regulated in a c-myc-transfected melanoma cell line. These data suggest that myc genes function as major regulators of the protein synthesis machinery.
Asunto(s)
Regulación Neoplásica de la Expresión Génica , Genes myc/genética , Neuroblastoma/genética , Biosíntesis de Proteínas/genética , Ribosomas/genética , Perfilación de la Expresión Génica/métodos , Biblioteca de Genes , Glucólisis/genética , Humanos , Melanoma Experimental/genética , ARN Mensajero/genética , ARN Ribosómico/biosíntesis , Proteínas Ribosómicas/biosíntesis , Proteínas Ribosómicas/genética , Factores de Tiempo , Regulación hacia ArribaRESUMEN
The chromosomal position of human genes is rapidly being established. We integrated these mapping data with genome-wide messenger RNA expression profiles as provided by SAGE (serial analysis of gene expression). Over 2.45 million SAGE transcript tags, including 160,000 tags of neuroblastomas, are presently known for 12 tissue types. We developed algorithms to assign these tags to UniGene clusters and their chromosomal position. The resulting Human Transcriptome Map generates gene expression profiles for any chromosomal region in 12 normal and pathologic tissue types. The map reveals a clustering of highly expressed genes to specific chromosomal regions. It provides a tool to search for genes that are overexpressed or silenced in cancer.
Asunto(s)
Cromosomas Humanos/genética , Expresión Génica , Genoma Humano , Neoplasias/genética , Mapeo Físico de Cromosoma , ARN Mensajero/genética , Algoritmos , Bases de Datos Factuales , Perfilación de la Expresión Génica , Biblioteca de Genes , Silenciador del Gen , Humanos , Familia de Multigenes , Programas Informáticos , Transcripción GenéticaRESUMEN
BACKGROUND: In patients with chronic hepatitis C (HCV) Interferon-alpha (IFN) treatment for 12-18 months is more effective than 6 months in inducing a sustained virological response. METHODS: In a multicenter, randomized, controlled trial, 88 patients with chronic HCV were enrolled (47 treated with IFN-alpha2b and 41 constituted an untreated control group). Treatment consisted of 5 million units (MU) IFN thrice a week (tiw) for 8 weeks and subsequently 2.5 MU IFN tiw for 16 weeks ('standard treatment'). After week 24 ('long-term treatment'), in virological non-responders treatment was continued using 5 MU IFN tiw for up to week 156, whereas in virological responders IFN was discontinued. In case of a virological relapse, treatment with 5 MU IFN tiw was restarted and continued up to week 156. RESULTS: Sustained virological response rate was 6/47 (13%) after standard treatment and increased to 19/47 (40%) after long-term treatment (McNemar paired test; P = 0.002). Of the 18 patients with a breakthrough or relapse during or after standard treatment, 14 (78%) became sustained virological responders upon long-term treatment. Of the 4 patients who did not have a sustained virological response after long-term treatment, 3 did not receive complete treatment due to side effects and/or non-compliance. In patients who failed to respond to standard treatment, no virological response was observed during long-term treatment. In the control group, no spontaneous clearance of HCV was observed. CONCLUSIONS: Long-term IFN (re)treatment enhanced the virological sustained response rate significantly and was particularly effective in patients with a breakthrough or relapse following standard treatment.
Asunto(s)
Antivirales/administración & dosificación , Hepatitis C Crónica/tratamiento farmacológico , Interferón-alfa/administración & dosificación , Adulto , Antivirales/uso terapéutico , Esquema de Medicación , Femenino , Hepacivirus/aislamiento & purificación , Hepatitis C Crónica/virología , Humanos , Interferón alfa-2 , Interferón-alfa/uso terapéutico , Masculino , ARN Viral/sangre , Proteínas Recombinantes , Recurrencia , Factores de Tiempo , Carga ViralRESUMEN
BACKGROUND: Serial Analysis of Gene Expression (SAGE) is an efficient method to establish a complete mRNA expression profile of a tissue. PROCEDURE: We applied SAGE to identify expression of developmental control genes in neuroblastoma. Results. The human homologue of the Drosophila Delta gene Delta like-1 (DLK1) was shown to have an unusually high expression in a SAGE library of the SK-N-FI neuroblastoma cell line. Northern blot analysis confirmed high DLK1 expression in SK-N-FI and several other neuroblastoma cell lines. Signalling between Delta and its receptor Notch controls many differentiation steps in Drosophila and man, including neural crest cell fate decision. CONCLUSIONS: Our data therefore suggest a role for the Delta-Notch pathway in neuroblast differentiation.
Asunto(s)
Proteínas de Unión al ADN/genética , Drosophila/genética , Regulación Neoplásica de la Expresión Génica , Neuroblastoma/genética , Animales , Factores de Transcripción con Motivo Hélice-Asa-Hélice Básico , Proteínas de Drosophila , Humanos , Proteínas Represoras , Células Tumorales CultivadasRESUMEN
We compared the performance of four assays for detection of hepatitis B virus (HBV) DNA: the PCR; the branched DNA hybridization assay (Chiron); and two hybridization assays that use liquid hybridization (Abbott) or direct membrane hybridization (MH). Testing 109 random hepatitis B surface antigen-positive patient samples, the percentages found to be HBV DNA positive among 30 hepatitis B e antigen (HBeAg)-positive samples and 79 HBeAg-negative samples were as follows: PCR, 100 and 90%; Chiron, 73 and 25%; Abbott, 67 and 13%; and MH, 40 and 8%. In six hepatitis B surface antigen-positive, HBeAg-negative samples, all three hybridization assays detected HBV DNA. Testing dilutions prepared from the Eurohep HBV DNA standards, the detection limits of the assays appeared to be the following: PCR, 2.5 x 10(2) HBV genomes per ml; Chiron, 2.5 x 10(6) genomes per ml; and Abbott and MH, 2.5 x 10(7) genomes per ml. HBV DNA levels in the dilution series, as reported by the Chiron and MH assays, were, on average, 2 times higher than calculated; the Abbott results were, on average, 19 times lower than calculated. We concluded that high levels of HBV DNA and the presence of HBeAg do not necessarily coincide, that the application of hybridization assays is limited to the monitoring of relatively high levels of HBV DNA, and that further standardization of quantitative HBV DNA assays is necessary to facilitate comparison of HBV DNA levels.
Asunto(s)
ADN Viral/aislamiento & purificación , Virus de la Hepatitis B/aislamiento & purificación , Hepatitis B/virología , Hibridación de Ácido Nucleico , Reacción en Cadena de la Polimerasa , Secuencia de Bases , Estudios de Evaluación como Asunto , Hepatitis B/sangre , Hepatitis B/inmunología , Antígenos de Superficie de la Hepatitis B/sangre , Antígenos e de la Hepatitis B/sangre , Virus de la Hepatitis B/genética , Virus de la Hepatitis B/inmunología , Humanos , Datos de Secuencia Molecular , Valor Predictivo de las Pruebas , Juego de Reactivos para Diagnóstico , Sensibilidad y EspecificidadRESUMEN
Two new rapid enzyme immunoassays (EIAs) for detecting respiratory syncytial virus (RSV), Directigen (Becton Dickinson Microbiology Systems) and TestPack (Abbott Diagnostics) were compared with virus isolation and direct immunofluorescence by using fresh specimens. The sensitivities of both EIAs were low (72 to 73%), but when initial specimens were used, TestPack had a high sensitivity (92%) in contrast to that of Directigen (76%). Because of its high sensitivity and specificity, TestPack can be used for diagnosis of RSV in acute disease.