RESUMEN
More and more clinical observations and trials support the concept of heterogeneity of atheroma according to the arterial bed. In a pilot study named "Étude Comparative des Lésions Athéromateuses" (ECLA), we have shown that carotid and femoral plaques possess different characteristics. Carotid arteries display increased lipid content compared to femoral arteries whereas femoral arteries are more prone to calcify and to develop osteoid metaplasia. These observations should lead the researcher and the clinician to look at the cellular and molecular mechanisms governing the heterogeneity of atheromas. At last, a better understanding of the characteristics of plaques should help us to determine plaque stability, to prevent cardiovascular events and to choose the best medical, endovascular or surgical option.
Asunto(s)
Estenosis Carotídea/clasificación , Placa Aterosclerótica/clasificación , Arterias Carótidas/química , Estenosis Carotídea/patología , Arteria Femoral/química , Arteria Femoral/patología , Humanos , Lípidos/análisis , Metaplasia , Pericitos/fisiología , Proyectos Piloto , Placa Aterosclerótica/patología , Calcificación Vascular/clasificación , Calcificación Vascular/patología , Resistencia Vascular/fisiologíaRESUMEN
Global and/or dynamic analysis of the cardiac transcriptome may improve our understanding of the adaptation of cardiac tissue or cells to different physiological or pathological conditions. The achievement of sequencing projects on mammalian genomes and the development of DNA chip technology have dramatically extended the scale of gene expression studies from a candidate gene approach to a system approach. In current DNA chip experiments, expression levels of thousands of genes can be determined simultaneously. Obviously, the huge quantities of objects and information generated by these experiments require a computational management of the expression data with adequate mathematical (mostly statistical) algorithms. Here, we will discuss the principle and experimental key points of DNA chips. Four examples will be cited to illustrate applications in the cardiovascular system.
Asunto(s)
Miocardio/metabolismo , Análisis de Secuencia por Matrices de Oligonucleótidos , Animales , Fenómenos Fisiológicos Cardiovasculares , Perfilación de la Expresión Génica , Humanos , Transcripción GenéticaRESUMEN
Heart failure is a multifactorial disease that may result from different initiating events. To contribute to an improved comprehension of normal cardiac function and the molecular events leading to heart failure, we performed large-scale gene expression analysis of failing and nonfailing human ventricle. Our aim was to define and compare expression profiles of 4 specific pathophysiological cardiac situations: 1) left ventricle (LV) from nonfailing heart; 2) LV from failing hearts affected by dilated cardiomyopathy (DCM); 3) LV from failing hearts affected by ischemic CM (ICM); 4) right ventricle (RV) from failing hearts affected by DCM or ICM. We used oligonucleotide arrays representing approximately 12,000 human genes. After stringent numerical analyses using several statistical tests, we identified 1,306 genes with a similar expression profile in all 4 cardiac situations, therefore representative of part of the human cardiac expression profile. A total of 95 genes displayed differential expression between failing and nonfailing heart samples, reflecting a reversal to developmental gene expression, dedifferentiation of failing cardiomyocytes, and involvement of apoptosis. Twenty genes were differentially expressed between failing LV and failing RV, identifying possible candidates for different functioning of both ventricles. Finally, no genes were found to be significantly differentially expressed between failing DCM and failing ICM LV, emphasizing that transcriptomal analysis of explanted hearts results mainly in identification of expression profiles of end-stage heart failure and less in determination of expression profiles of the underlying etiology. Taken together, our data resulted in identification of putative transcriptomal landmarks for normal and disturbed cardiac function.
Asunto(s)
Perfilación de la Expresión Génica/métodos , Insuficiencia Cardíaca/genética , Miocardio/química , Miocardio/metabolismo , Análisis de Secuencia por Matrices de Oligonucleótidos/métodos , Transcripción Genética/genética , Adolescente , Adulto , Anciano , Cardiomiopatías/genética , Cardiomiopatías/fisiopatología , Fibrosis Quística/genética , Femenino , Insuficiencia Cardíaca/fisiopatología , Trasplante de Corazón-Pulmón , Humanos , Masculino , Persona de Mediana Edad , Donantes de Tejidos , Disfunción Ventricular Izquierda/genética , Disfunción Ventricular Izquierda/fisiopatologíaRESUMEN
Sporadic childhood tumors associated with Beckwith-Wiedemann syndrome (BWS) all show abnormalities of the same region on chromosome 11. In addition to chromosome 11, other chromosome regions are affected in some of these tumor types. In this study we analyzed the region on chromosome 1p involved in the etiology of BWS-associated tumors, Wilms tumor, rhabdomyosarcoma, and hepatoblastoma. For this purpose we determined the location of two novel translocation breakpoints in this chromosome region in cells from a Wilms tumor and cells from a rhabdomyosarcoma. We constructed a map of the region and found that both breakpoints are separated by at least 875 kb. We identified a PAC clone which crosses the rhabdomyosarcoma breakpoint and found several exons within this clone. We established that this breakpoint is located proximal to the PAX7 gene and, therefore, identified a new region involved in the etiology of rhabdomyosarcomas.
Asunto(s)
Rotura Cromosómica/genética , Cromosomas Humanos Par 1/genética , Hepatoblastoma/genética , Proteínas de Homeodominio , Rabdomiosarcoma/genética , Translocación Genética/genética , Tumor de Wilms/genética , Síndrome de Beckwith-Wiedemann/complicaciones , Niño , Paseo de Cromosoma , Cromosomas Artificiales de Levadura/genética , Clonación Molecular , Mapeo Contig , Electroforesis en Gel de Campo Pulsado , Exones/genética , Ligamiento Genético/genética , Hepatoblastoma/complicaciones , Humanos , Hibridación Fluorescente in Situ , Datos de Secuencia Molecular , Proteínas Musculares/genética , Proteínas del Tejido Nervioso/genética , Factor de Transcripción PAX7 , Receptores de Cannabinoides , Receptores de Droga/genética , Rabdomiosarcoma/complicaciones , Células Tumorales Cultivadas , Tumor de Wilms/complicacionesRESUMEN
A specific subset of solid childhood tumors-Wilms' tumor, adrenocortical carcinoma, rhabdomyosarcoma, and hepatoblastoma-is characterized by its association with Beckwith-Wiedemann syndrome. Genetic abnormalities found in these tumors affect the same chromosome region (11p15), which has been implicated in the etiology of Beckwith-Wiedemann syndrome. This suggests that the development of these tumors occurs along a common genetic pathway involving chromosome 11. To search for additional common genetic pathways, this article reviews the genetic data published for these tumors. It was found that, up until now, the only genetic abnormalities detected in all four tumors affect chromosome band 11p15 and the TP53 gene. In addition, there are several aberrations that occur in two or three of the neoplasms. It is concluded that, of the four tumors, the genetic relationship is most evident between Wilms' tumor and rhabdomyosarcoma.
Asunto(s)
Síndrome de Beckwith-Wiedemann/genética , Neoplasias/genética , Animales , HumanosRESUMEN
We applied the technique of comparative genomic hybridization (CGH) to a series of 16 hepatoblastomas. Our goals were (1) to identify all quantitative chromosome abnormalities that appear in this type of tumor and (2) to compare the results with data from similar studies on other tumors associated with the Beckwith-Wiedemann syndrome (BWS). We found that the most commonly detected (> 30%) chromosome abnormalities were gains of chromosomes 1, 2, 7, 8, and 17. Losses of chromosomes were found in only a few cases. On comparing our results with those from studies on the BWS-associated tumors, Wilms tumor and rhabdomyosarcoma, it became clear that three chromosome regions, namely, 7q, 8q, and 17q, were the ones most commonly involved in all three types of tumors. These regions, therefore, may harbor genes that play a role in the etiology of BWS-associated tumors in general.
Asunto(s)
Síndrome de Beckwith-Wiedemann/genética , Aberraciones Cromosómicas/genética , Genoma Humano , Hepatoblastoma/genética , Rabdomiosarcoma/genética , Tumor de Wilms/genética , Edad de Inicio , Aneuploidia , Síndrome de Beckwith-Wiedemann/patología , Preescolar , Aberraciones Cromosómicas/patología , Deleción Cromosómica , Trastornos de los Cromosomas , Pruebas Genéticas , Hepatoblastoma/patología , Humanos , Lactante , Neoplasias Renales/genética , Neoplasias Renales/patología , Hibridación de Ácido Nucleico , Rabdomiosarcoma/patología , Tumor de Wilms/patologíaRESUMEN
In this study we have applied the technique of comparative genomic hybridization (CGH) to a large series of sporadic Wilms tumors, including six samples of the associated nephroblastomatosis. The data obtained were compared with the findings of molecular studies carried out on the same material. The aims of the study were (1) to characterize the range of genetic variation in sporadic Wilms tumor and nephroblastomatosis, (2) to determine whether changes could be found that have not been detected by commonly used techniques, and (3) to compare the sensitivity of CGH with that of conventional molecular analysis. The chromosomes that showed gains and losses by CGH were similar to those previously found in molecular and cytogenetic studies, however loss of 4q was a new event identified in 2 out of 46 tumors. We did not detect amplified genetic material. Comparison of the data from the nephroblastomatosis and tumor samples from the same patient showed that loss of 7p may be associated with malignant transformation, and that losses in 1p, 11p, 4q and gains in 1q and 12q can be early events; whilst loss in 9p and gain of 8, 10q and 18 are possible secondary changes in tumor development. The combined CGH and molecular techniques used demonstrated involvement of two specific 1p regions in the etiology of Wilms tumor.
Asunto(s)
Aberraciones Cromosómicas , Genes del Tumor de Wilms , Hibridación Fluorescente in Situ/métodos , Neoplasias Renales/genética , Tumor de Wilms/genética , Deleción Cromosómica , Cromosomas Humanos/genética , Cromosomas Humanos/ultraestructura , Cromosomas Humanos Par 1/genética , Cromosomas Humanos Par 1/ultraestructura , Femenino , Marcadores Genéticos , Técnicas Genéticas , Variación Genética , Genoma Humano , Heterocigoto , Humanos , MasculinoRESUMEN
The Beckwith-Wiedemann syndrome (BWS) is an overgrowth malformation syndrome that occurs with an incidence of 1:13,700 births. There is a striking incidence of childhood tumors found in BWS patients. Various lines of investigation have localized "imprinted" genes involved in BWS and associated childhood tumors to 11p15. High resolution mapping of 8 rare balanced chromosomal BWS rearrangements enabled us to identify three distinct regions on chromosome 11p15 that might harbor genes involved in the above-mentioned disorders. These results suggest genetic heterogeneity that correlates with the clinical heterogeneity seen in the patients studied. Expressed candidate gene sequences from these regions have been cloned and partly sequenced. These transcripts are either disrupted by or are at least within a few kb of these BWS chromosome breakpoints. So far, zinc-finger sequences and one Kruppel-associated box (KRAB) domain were found in independent candidate genes which are compatible with a regulating function of growth promoting genes. The abundance of expression of these genes varies from low abundant in all adult and fetal tissues tested to detectable on Northern blots of adult tissues. In addition to our 11p15 studies we have analyzed additional chromosome regions, in particular 1p. Cytogenetic, loss of heterozygosity (LOH) and comparative genomic hybridization (CGH) studies have identified 1p35 as a region of interest. A positional cloning effort to identify a balanced 1p35 translocation found in a Wilms tumor has led to the isolation of a YAC, crossing this breakpoint.
Asunto(s)
Síndrome de Beckwith-Wiedemann/genética , Clonación Molecular , Trastornos del Crecimiento/genética , Neoplasias/genética , Adulto , Secuencia de Bases , Niño , Mapeo Cromosómico , Cromosomas Humanos Par 11/genética , Eliminación de Gen , Regulación de la Expresión Génica , Reordenamiento Génico , Impresión Genómica/genética , Crecimiento/genética , Heterocigoto , Humanos , Transcripción Genética/genética , Dedos de Zinc/genéticaRESUMEN
Comparative genomic hybridization (CGH) is a powerful tool for analyzing unbalanced chromosomal rearrangements in a variety of tissues. However, reproducibility of the technique is poor. We have developed an alternative protocol involving microwave denaturation of the metaphase chromosome preparations prior to the hybridization step. The advantage of this method for CGH is the retention of the morphology of the chromosomes and hence an improved chromosome banding pattern. Furthermore, it results in a consistently strong hybridization which is not dependent on the batch of lymphocytes used to obtain the metaphase chromosome spreads. This procedure has also proved to be applicable to nucleic acid hybridizations in general. The protocol, its application and the results of this method in CGH is discussed. Furthermore preliminary results of this method in paint and DNA probe hybridizations to chromosome spreads and to RNA in tissue sections are presented.
Asunto(s)
Microondas , Desnaturalización de Ácido Nucleico , ADN de Neoplasias/análisis , Genoma , Humanos , Hibridación Fluorescente in Situ/métodos , Reproducibilidad de los Resultados , Tumor de Wilms/genética , Tumor de Wilms/patologíaRESUMEN
Beckwith-Wiedemann syndrome (BWS) involves fetal overgrowth and predisposition to a wide variety of embryonal tumors of childhood. We have previously found that BWS is genetically linked to 11p15 and that this same band shows loss of heterozygosity in the types of tumors to which children with BWS are susceptible. However, 11p15 contains > 20 megabases, and therefore, the BWS and tumor suppressor genes could be distinct. To determine the precise physical relationship between these loci, we isolated yeast artificial chromosomes, and cosmid libraries from them, within the region of loss of heterozygosity in embryonal tumors. Five germ-line balanced chromosomal rearrangement breakpoint sites from BWS patients, as well as a balanced chromosomal translocation breakpoint from a rhabdoid tumor, were isolated within a 295- to 320-kb cluster defined by a complete cosmid contig crossing these breakpoints. This breakpoint cluster terminated approximately 100 kb centromeric to the imprinted gene IGF2 and 100 kb telomeric to p57KIP2, an inhibitor of cyclin-dependent kinases, and was located within subchromosomal transferable fragments that suppressed the growth of embryonal tumor cells in genetic complementation experiments. We have identified 11 transcribed sequences in this BWS/tumor suppressor coincident region, one of which corresponded to p57KIP2. However, three additional BWS breakpoints were > 4 megabases centromeric to the other five breakpoints and were excluded from the tumor suppressor region defined by subchromosomal transferable fragments. Thus, multiple genetic loci define BWS and tumor suppression on 11p15.
Asunto(s)
Síndrome de Beckwith-Wiedemann/genética , Deleción Cromosómica , Cromosomas Humanos Par 11 , Secuencia de Bases , Línea Celular , Niño , Mapeo Cromosómico , Cromosomas Artificiales de Levadura , Secuencia Conservada , Cósmidos , Reordenamiento Génico , Genes Supresores de Tumor , Humanos , Riñón , Neoplasias de Células Germinales y Embrionarias/genética , Lugares Marcados de Secuencia , Transcripción GenéticaRESUMEN
The insulin-like growth factor-II (IGF2) and H19 genes are imprinted in mouse and human, with expression of the paternal IGF2 and maternal H19 alleles. IGF2 undergoes loss of imprinting (LOI) in most Wilms' tumours (WT). We now show that: (i) LOI of IGF2 is associated with a 80-fold down regulation of H19 expression; (ii) these changes are associated with alterations in parental-origin-specific, tissue-independent sites of DNA methylation in the H19 promoter; and (iii) loss of heterozygosity is also associated with loss of H19 expression. Thus, imprinting of a large domain of the maternal chromosome results in a reversal to a paternal epigenotype. These data also suggest an epigenetic mechanism for inactivation of H19 as a tumour suppressor gene.
Asunto(s)
ADN de Neoplasias/genética , Regulación Neoplásica de la Expresión Génica , Genes Supresores de Tumor , Impresión Genómica , Factor II del Crecimiento Similar a la Insulina/genética , Neoplasias Renales/genética , ARN Mensajero/genética , ARN Neoplásico/genética , Tumor de Wilms/genética , ADN de Neoplasias/química , Desarrollo Embrionario y Fetal/genética , Femenino , Genes , Humanos , Masculino , Metilación , Especificidad de Órganos , Regiones Promotoras Genéticas , ARN Mensajero/biosíntesis , ARN Neoplásico/biosíntesis , Transcripción GenéticaRESUMEN
Cytogenetic and DNA analyses of patients with the Beckwith-Wiedemann syndrome (BWS) enabled us to refine the localization of the syndrome at 11p15.3-pter to two distinct regions. One chromosome region (BWSCR1) is near the insulin (INS) and insulin-like growth factor 2 (IGF2) genes. The other region (BWSCR2) is more proximal near two sequences with zinc-binding finger motifs and a number of known and putative genes. This latter region, at least, seems to be associated with the development of childhood tumors. Our results strongly support the proposed involvement of parental imprinting in the etiology of BWS since all balanced chromosomal abnormalities in these patients were maternally transmitted while the mothers were phenotypically normal. We demonstrate that such an autosomal balanced rearrangement can lead to a specific maternal hypomethylation of the INS/IGF2 genes localized distal to the breakpoint. This underlines the role of these genes in the etiology of the syndrome.
Asunto(s)
Síndrome de Beckwith-Wiedemann/genética , Aberraciones Cromosómicas , Cromosomas Humanos Par 11 , Síndromes Neoplásicos Hereditarios/genética , Síndrome de Beckwith-Wiedemann/complicaciones , Niño , Mapeo Cromosómico , ADN/metabolismo , Femenino , Expresión Génica , Genes Supresores de Tumor , Humanos , Hibridación Fluorescente in Situ , Insulina/genética , Factor II del Crecimiento Similar a la Insulina/genética , Cariotipificación , Masculino , Metilación , Síndromes Neoplásicos Hereditarios/complicaciones , Padres , Linaje , Polimorfismo de Longitud del Fragmento de Restricción , Factores Sexuales , Translocación Genética , Trisomía , Tumor de Wilms/complicaciones , Tumor de Wilms/genéticaRESUMEN
One of the most exciting areas of molecular oncology is the convergence of two independent lines of evidence suggesting involvement of multiple tumor suppressor genes in a given type of cancer. First, epidemiology and somatic cell genetics indicate the presence of multiple tumor suppressor genes in each of several malignancies. Second, cancers often lose multiple chromosomal regions during tumor progression. We will use two tumors, colorectal cancer and Wilms tumor, to illustrate the questions that multiple tumor suppressor genes raise.