Diversité et plasticité des tumeurs de l’enfant

Publications de l’équipe

Année de publication : 2007

Anne Vincent-Salomon, Nadège Gruel, Carlo Lucchesi, Gaëtan MacGrogan, Remi Dendale, Brigitte Sigal-Zafrani, Michel Longy, Virginie Raynal, Gaëlle Pierron, Isabelle de Mascarel, Corinne Taris, Dominique Stoppa-Lyonnet, Jean-Yves Pierga, Rémy Salmon, Xavier Sastre-Garau, Alain Fourquet, Olivier Delattre, Patricia de Cremoux, Alain Aurias (2007 Apr 10)

Identification of typical medullary breast carcinoma as a genomic sub-group of basal-like carcinomas, a heterogeneous new molecular entity.

Breast cancer research : BCR : R24 En savoir plus
Résumé

Typical medullary breast carcinoma (MBC) has recently been recognized to be part of the basal-like carcinoma spectrum, a feature in agreement with the high rate of TP53 mutations previously reported in MBCs. The present study was therefore designed to identify phenotypic and genetic alterations that distinguish MBCs from basal-like carcinomas (BLC).

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Année de publication : 2006

Patricia Albanese, Marie-France Belin, Olivier Delattre (2006 Aug 16)

The tumour suppressor hSNF5/INI1 controls the differentiation potential of malignant rhabdoid cells.

European journal of cancer (Oxford, England : 1990) : 2326-34 En savoir plus
Résumé

Malignant rhabdoid tumours (MRT) are highly aggressive cancers of early childhood that arise in different organs or tissues. The unifying criterion for these tumours is the presence of inactivating mutations of the hSNF5/INI1 tumour suppressor gene which encodes a core subunit of the chromatin remodelling SWI/SNF complex. Using a variety of markers we analysed the phenotypic traits of MON and DEV cell lines derived respectively from an undifferentiated abdominal MRT and from a brain MRT. DEV cells express spontaneously a wide range of neural and glial markers. It can be induced to differentiate into the neural lineage following hSNF5/INI1 expression with appearance of neurite processes, strong increase of neural markers and decrease of glial markers. A less pronounced neural differentiation is also observed with MON cells, which possess more primitive polyphenotypic features with positivity for markers from the three embryonic layers. Finally, we show that the neural differentiation of rat PC12 cells in the presence of nerve growth factor (NGF) is strongly impaired when hSNF5/INI1 expression is inhibited by RNA interference. Altogether these results indicate that hSNF5/INI1 is an essential subunit for SWI/SNF-dependant induction of neural differentiation programs. Further experiments should enable documentation of whether it provides instructive or permissive signals for differentiation.

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Patricia de Cremoux, Nathalie Jourdan-Da-Silva, Jérôme Couturier, Carine Tran-Perennou, Gudrun Schleiermacher, Pascale Fehlbaum, François Doz, Véronique Mosseri, Olivier Delattre, Jerzy Klijanienko, Philippe Vielh, Jean Michon (2006 Apr 13)

Role of chemotherapy resistance genes in outcome of neuroblastoma.

Pediatric blood & cancer : 311-7 En savoir plus
Résumé

Neuroblastoma is a heterogeneous pediatric disease. Most patients with localized disease usually have a favorable prognosis, but patients with advanced disease have a poor prognosis despite combination chemotherapy. Treatment failure may be attributable to resistance to cytotoxic drugs.

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Année de publication : 2005

Vanessa Bonazzi, Souhila Medjkane, Frédérique Quignon, Olivier Delattre (2005 Sep 13)

Complementation analyses suggest species-specific functions of the SNF5 homology domain.

Biochemical and biophysical research communications : 634-8 En savoir plus
Résumé

Inactivation on both alleles of the hSNF5/INI1 tumor suppressor gene which encodes a subunit of the human SWI/SNF chromatin remodelling complex occurs in most malignant rhabdoid tumors. No paralog of hSNF5/INI1 is identified in the human genome. In contrast, it has two homologs in the yeast Saccharomyces cerevisiae, SNF5 and SFH1 which encode core components of the ySWI/SNF and RSC complexes, respectively. The homology mainly concerns an approximately 200 amino acid region termed the SNF5 homology domain. We have tested the ability of the hSNF5/INI1-wild type gene product and of chimerical constructs in which the yeast SNF5 domains were replaced by that of the human protein, to complement yeast snf5 and sfh1 phenotypes. Neither growth deficiencies on different carbon sources of snf5 yeasts nor the lethality of the sfh1 phenotype could be rescued. This strongly suggests that the SNF5 homology domain presents species-specific functions.

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Ahmed Idbaih, Yannick Marie, Gaëlle Pierron, Caroline Brennetot, Khê Hoang-Xuan, Michèle Kujas, Karima Mokhtari, Marc Sanson, Julie Lejeune, Alain Aurias, Olivier Delattre, Jean-Yves Delattre (2005 Sep 1)

Two types of chromosome 1p losses with opposite significance in gliomas.

Annals of neurology : 483-7 En savoir plus
Résumé

Deletion of the short arm of chromosome 1 (1p) is considered a favorable prognostic factor in glial tumors. High-density array-comparative genomic hybridization analysis of 108 gliomas shows two distinct types of 1p deletions. Complete hemizygous losses of 1p, which are tightly associated with 19q loss and oligodendroglial phenotype, and partial 1p deletions mainly observed in astrocytic tumors and not associated with 19q loss. Whereas the first type predicts longer overall and progression-free survival (p < 0.0001), the second type has a pejorative prognostic value. Complete 1p-arm evaluation therefore is required to appreciate the real clinical significance of 1p loss in gliomas.

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Franck Bourdeaut, Delphine Trochet, Isabelle Janoueix-Lerosey, Agnès Ribeiro, Anne Deville, Carole Coz, Jean-François Michiels, Stanislas Lyonnet, Jeanne Amiel, Olivier Delattre (2005 Jun 14)

Germline mutations of the paired-like homeobox 2B (PHOX2B) gene in neuroblastoma.

Cancer letters : 51-8 En savoir plus
Résumé

Hereditary predisposition to neuroblastoma accounts for less than 5% of neuroblastomas and is probably heterogeneous. Recently, a predisposition gene has been mapped to 16p12-p13, but has not yet been identified. Occurrence of neuroblastoma in association with congenital central hypoventilation and Hirschsprung’s disease suggests that genes, involved in the development of neural-crest-derived cells, may be altered in these conditions. The recent identification of PHOX2B as the major disease-causing gene in congenital central hypoventilation prompted us to test it as a candidate gene in familial neuroblastoma. We report a family with three first-degree relatives with neuroblastic tumours (namely two ganglioneuromas and one neuroblastoma) in one branch and two siblings with Hirschsprung’s disease in another branch. A constitutional R100L PHOX2B mutation was identified in all three patients affected with tumours. We also report a germline PHOX2B mutation in one patient treated for Hirschsprung’s disease who subsequently developed a multifocal neuroblastoma in infancy. Both mutations disrupt the homeodomain of the PHOX2B protein. No loss of heterozygosity at the PHOX2B locus was observed in the tumour, suggesting that haplo-insufficiency, gain of function or dominant negative effects may account for the oncogenic effects of these mutations. These observations identify PHOX2B as the first predisposing gene to hereditary neuroblastic tumours.

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Gudrun Schleiermacher, Franck Bourdeaut, Valérie Combaret, Gaelle Picrron, Virginie Raynal, Alain Aurias, Agnes Ribeiro, Isabelle Janoueix-Lerosey, Olivier Delattre (2005 Mar 1)

Stepwise occurrence of a complex unbalanced translocation in neuroblastoma leading to insertion of a telomere sequence and late chromosome 17q gain.

Oncogene : 3377-84 En savoir plus
Résumé

In neuroblastoma, the most frequent genetic alterations are unbalanced translocations involving chromosome 17. To gain insights into these rearrangements, we have characterized a previously identified der(1)t(1;17) of the CLB-Bar cell line. The 17q breakpoint was mapped by FISH. Subsequently, a rearranged fragment was identified by Southern analysis, cloned in a lambda vector and sequenced. The chromosome rearrangement is more complex than expected due to the presence of an interstitial 4p telomeric sequence between chromosome 1p and 17q. Three different genes, which may play a role in neuroblastoma development, are disrupted by the translocation breakpoints. Indeed, the 3’UTR of the PIP5K2B gene on chromosome 17q is directly fused to the (TTAGGG)n repeat of the chromosome 4p telomere, and the (1;4) fusion disrupts the MACF1 (microtubule-actin crosslinking factor 1) and POLN genes, respectively. Interestingly, the (1;4) fusion was present at diagnosis and at relapse, whereas the (4;17) fusion was detected at relapse only, leading to a secondary 17q gain confirmed by array CGH therefore indicating that 17q gain may not be a primary event in neuroblastoma. Finally, screening of a panel of neuroblastoma cell lines identified interstitial telomeric sequences in three other cases, suggesting that this may be a recurrent mechanism leading to unbalanced translocations in neuroblastoma.

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Marie-Françoise Rousseau-Merck, Laurence Fiette, Agnès Klochendler-Yeivin, Olivier Delattre, Alain Aurias (2005 Feb 22)

Chromosome mechanisms and INI1 inactivation in human and mouse rhabdoid tumors.

Cancer genetics and cytogenetics : 127-33 En savoir plus
Résumé

The human rhabdoid tumorigenesis orchestrated by INI1 inactivation is associated with specific rearrangements of chromosome 22 that correlate with preferential anatomic tumor locations. A literature review revealed significant correlations between an apparently normal karyotype and kidney tumors, monosomy 22 and cerebral tumors, and chromosome 22 translocations and tumors at other anatomic sites. In the mouse rhabdoid tumor model, specifically in the four tumors that we tested for loss of heterozygosity, neither partial deletion nor monosomy of chromosome 10 could be detected. In contrast to the human data, the only chromosome mechanism involved in the 18 mouse tumors studied appears to be a mitotic recombination or a nondisjunction-duplication. Additionally, and despite mouse tumor incidence across a variety of sites, no rhabdoid tumor could be observed in the mouse kidney. These data suggest that the chromosome mechanisms for INI1 inactivation and the selective cell survival pressure differ in human and mouse.

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Année de publication : 2004

Alexandre Prieur, Franck Tirode, Pinchas Cohen, Olivier Delattre (2004 Jul 30)

EWS/FLI-1 silencing and gene profiling of Ewing cells reveal downstream oncogenic pathways and a crucial role for repression of insulin-like growth factor binding protein 3.

Molecular and cellular biology : 7275-83 En savoir plus
Résumé

Ewing tumors are characterized by abnormal transcription factors resulting from the oncogenic fusion of EWS with members of the ETS family, most commonly FLI-1. RNA interference targeted to the junction between EWS and FLI-1 sequences was used to inactivate the EWS/FLI-1 fusion gene in Ewing cells and to explore the resulting phenotype and alteration of the gene expression profile. Loss of expression of EWS/FLI-1 resulted in the complete arrest of growth and was associated with a dramatic increase in the number of apoptotic cells. Gene profiling of Ewing cells in which the EWS/FLI-1 fusion gene had been inactivated identified downstream targets which could be grouped in two major functional clusters related to extracellular matrix structure or remodeling and regulation of signal transduction pathways. Among these targets, the insulin-like growth factor binding protein 3 gene (IGFBP-3), a major regulator of insulin-like growth factor 1 (IGF-1) proliferation and survival signaling, was strongly induced upon treating Ewing cells with EWS/FLI-1-specific small interfering RNAs. We show that EWS/FLI-1 can bind the IGFBP-3 promoter in vitro and in vivo and can repress its activity. Moreover, IGFBP-3 silencing can partially rescue the apoptotic phenotype caused by EWS/FLI-1 inactivation. Finally, IGFBP-3-induced Ewing cell apoptosis relies on both IGF-1-dependent and -independent pathways. These findings therefore identify the repression of IGFBP-3 as a key event in the development of Ewing’s sarcoma.

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Isabelle Janoueix-Lerosey, Eugene Novikov, Marta Monteiro, Nadège Gruel, Gudrun Schleiermacher, Béatrice Loriod, Catherine Nguyen, Olivier Delattre (2004 Jun 15)

Gene expression profiling of 1p35-36 genes in neuroblastoma.

Oncogene : 5912-22 En savoir plus
Résumé

Deletion of the chromosome 1p36 region is a frequent abnormality in neuroblastoma. To gain further insights into the role of this alteration in oncogenesis, we have constructed a specific cDNA microarray representing most known genes and ESTs from the 1p35-36 region and analysed the expression profiles of 15 neuroblastoma cell lines and 28 neuroblastoma tumours. Hierarchical clustering using expression levels of 320 cDNAs from 1p35-36 separated localized or 4S cases without 1p deletion from advanced stages and cell lines. Supervised learning classification enabled to predict reliably the status of chromosome 1p according to its expression profile. Around 15% of the genes or ESTs presented a significantly decreased expression in samples with 1p deletion as compared to 1p-normal samples suggesting that 1p deletion results in a gene dosage effect on a subset of genes critical for the development of 1p-deleted neuroblastoma. Several genes presumed to have functions in neural differentiation (CDC42, VAMP3, CLSTN1), signal transduction in neural cells (GNB1) and cell cycle regulation (STMN1, RPA2, RBAF600, FBXO6, MAD2L2) exhibited a decreased expression in samples presenting 1p deletion. The identification of such genes provides baseline information for further studies to elucidate how these genes could individually or collectively play a critical role in neuroblastoma tumorigenesis.

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Souhila Medjkane, Eugene Novikov, Isabella Versteege, Olivier Delattre (2004 May 20)

The tumor suppressor hSNF5/INI1 modulates cell growth and actin cytoskeleton organization.

Cancer research : 3406-13 En savoir plus
Résumé

hSNF5/INI1, which encodes a component of the ATP-dependent chromatin remodeling hSWI-SNF complex, is a tumor suppressor gene mutated in malignant rhabdoid tumors. We have developed a tetracycline-based hSNF5/INI1-inducible system in a hSNF5/INI1-deficient malignant rhabdoid tumor cell line and studied time course variation of 22,000 genes/expressed sequence tags upon hSNF5/INI1 induction. A total of 482 responsive genes were identified and further clustered into 9 groups of coregulated genes. Among genes with early and strong inductions, the use of a fusion protein with the hormone-binding domain of the estrogen receptor enabled the identification of a subset of direct targets regulated independently of de novo protein synthesis. We show that the G(1) arrest induced by hSNF5/INI1 is reversible and associated with the down-regulation of components of the DNA replication complex. We also identify an unsuspected role of hSNF5/INI1 in cytoskeleton organization. Indeed, induction of hSNF5/INI1 induces dramatic modifications of the cell shape including complete disruption of the actin stress fiber network and disappearance of focal adhesions associated with up-regulation of genes involved in the organization of the actin cytoskeleton. We document a strong decrease of Rho activity upon hSNF5/INI1 expression, suggesting that the regulation of this activity constitutes a crucial step of the hSNF5/INI1-induced reorganization of the actin network. This study identifies hSNF5/INI1 target genes and provides evidence that hSNF5/INI1 may modulate the cell cycle control and cytoskeleton organization through the regulation of the retinoblastoma protein-E2F and Rho pathways.

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Anne Fix, Martine Peter, Gaëlle Pierron, Alain Aurias, Olivier Delattre, Isabelle Janoueix-Lerosey (2004 May 13)

High-resolution mapping of amplicons of the short arm of chromosome 1 in two neuroblastoma tumors by microarray-based comparative genomic hybridization.

Genes, chromosomes & cancer : 266-70 En savoir plus
Résumé

Deletion of chromosome arm 1p is one of the most frequent genetic alterations in neuroblastoma. However, using conventional comparative genomic hybridization, we have observed amplifications on 1p in 2 neuroblastoma tumors at bands 1p34.2 and 1p36.3, respectively. Using a medium-resolution genomic array containing 178 PACs/BACs from 1p and then 2 high-resolution arrays containing contigs of overlapping PACs/BACs from the amplified regions, we could precisely map and delineate both amplicons. The 1p34.2 amplicon appeared as a homogeneous amplification unit, whereas the 1p36.3 amplicon had a more complex structure, with 2 noncontiguous, highly amplified regions and several moderate amplification units. In this case, fluorescence in situ hybridization analysis confirmed the amplification of several clones and indicated that the 2 highest amplification units corresponded to 2 populations of double minute chromosomes, one of which also contained the MYCN locus. This is the first report of 1p amplifications in primary neuroblastomas.

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Année de publication : 2003

Gudrun Schleiermacher, Virginie Raynal, Isabelle Janoueix-Lerosey, Valérie Combaret, Alain Aurias, Olivier Delattre (2003 Dec 30)

Variety and complexity of chromosome 17 translocations in neuroblastoma.

Genes, chromosomes & cancer : 143-50 En savoir plus
Résumé

In neuroblastoma, the most frequent genetic alteration is gain of chromosome arm 17q, which arises from unbalanced translocations. To document these genetic events more precisely, we performed an extensive study of chromosome 17 breakpoints in 27 neuroblastoma cell lines by using a combination of fluorescence in situ hybridization mapping with BAC/PAC clones and allele analysis with polymorphic markers. All cases exhibited one or more unbalanced chromosome 17 translocations, and 15 distinct breakpoint regions could be mapped. This high variability indicates that gene fusion or disruption events are extremely unlikely to account for the underlying oncogenic role of these translocations. However, breakpoints were not randomly distributed, most of them mapping to the proximal part of 17q. As a result of translocations, all cell lines but one exhibited gain of the 53.5 Mb–>qter fragment, bordered proximally by the clone CTC-462L7. The most telomeric breakpoint, flanked by the clone RP11-443M10, defined the 70.9 Mb–>qter fragment as a region of additional gain. In addition to chromosome gains, loss of heterozygosity for the short arm of chromosome 17 was observed in close to half the cases. It was either related to a chromosome 17 monosomy or to a uniparental isodisomy. Finally, in cases with a single normal chromosome 17, we show that the parental origin of the translocated chromosome 17 can be either distinct or identical to that of the normal chromosome. Similarly, multiple translocations within the same cell line can either involve the same or different chromosome 17 homologues, indicating the likely absence of parental origin bias in the generation of these alterations.

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Gudrun Schleiermacher, Isabelle Janoueix-Lerosey, Valérie Combaret, Josette Derré, Jérome Couturier, Alain Aurias, Olivier Delattre (2003 Feb 13)

Combined 24-color karyotyping and comparative genomic hybridization analysis indicates predominant rearrangements of early replicating chromosome regions in neuroblastoma.

Cancer genetics and cytogenetics : 32-42 En savoir plus
Résumé

Neuroblastoma is characterized by several distinct genetic alterations including MYCN amplification, chromosome 1p deletion and gain of chromosome 17. Although these alterations are thought to play a crucial role in oncogenesis, to date little is known about their underlying mechanisms. In order to more precisely document these genetic alterations, we have performed a combined study of 27 neuroblastoma cell lines using 24-color karyotyping (24-CK) and comparative genomic hybridization (CGH). 24-CK detected balanced translocations in 13 cases with recurrent involvement of chromosome 8. More importantly, 144 nonreciprocal translocations were observed in the 27 cell lines, with chromosome 1 as the most frequent recipient and chromosome 17 the most frequent donor. Each cell line exhibited at least one unbalanced translocation involving 17q, with 14 cell lines demonstrating more than one such translocation. Other recurrent alterations were amplification of the 2p24 chromosome region, which encodes the MYCN oncogene, losses of 1p, 3p and 11q, and gains of 1q and 7. In most cases, CGH profiles were directly linked to the presence of unbalanced translocations with gain of the donor fragment and loss of the replaced region on the recipient chromosome. Strikingly, over 60% of the chromosome breakpoints mapped to early replicating chromosome bands, which represent around 13% of the genome. Altogether these data suggest that neuroblastoma is characterized by rearrangements that predominantly involve chromosome fragments replicating early in the S-phase.

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Année de publication : 2002

Josiane Sancéau, Marie-France Poupon, Olivier Delattre, Xavier Sastre-Garau, Juana Wietzerbin (2002 Oct 26)

Strong inhibition of Ewing tumor xenograft growth by combination of human interferon-alpha or interferon-beta with ifosfamide.

Oncogene : 7700-9 En savoir plus
Résumé

Ewing sarcoma is the second most common bone tumor in childhood. Despite aggressive chemotherapy and radiotherapy strategies, the prognosis of patients with metastatic disease remains poor. We have recently reported that Ewing tumor cell proliferation was strongly inhibited by IFN-beta and to a lesser degree by IFN-alpha. Moreover, under IFN-beta treatment, some cell lines undergo apoptosis. Since the possibility of using IFNs for Ewing tumor treatments may be of interest, we have evaluated the efficacy of Hu-IFNs in a nude mice model of Ewing tumor xenografts. The results reported here show that human type I IFNs, Hu-IFN-alpha and Hu-IFN-beta impaired tumor xenograft take and displayed an anti-growth effect toward established xenografts. Furthermore, we have also shown that combined therapy with Hu-IFNs and ifosfamide (IFO), an alkylating agent widely used in high-dose chemotherapy of Ewing tumors, results in a strong antitumor effect. Pathological analysis showed that Hu-IFN-alpha/IFO and Hu-IFN-beta/IFO were characterized by a dramatic decrease in the mitotic index and marked necrosis, as well as extensive fibrosis associated with numerous calcifications. To our knowledge, this is the first demonstration of a potential antitumor effect of human type I IFNs and IFO on Ewing tumors, providing a rational foundation for a promising therapeutic approach to Ewing sarcoma.

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