RESUMO
Patients with NF1 microdeletion develop more neurofibromas at a younger age, and have an increased risk of malignant peripheral nerve sheath tumors (MPNSTs). We postulated that the increased risk of malignancy could be due to inactivation, in addition to NF1, of a second tumor suppressor gene located in the typical 1.4-Mb microdeletion found in most of the microdeleted patients. We investigated the expression of NF1, the other 16 protein-coding genes and the 2 microRNAs located in the 1.4-Mb microdeletion by means of real-time quantitative reverse-transcription polymerase chain reaction (RT-PCR) in a large series of human dermal and plexiform neurofibromas and MPNSTs. Five genes were significantly upregulated: OMG and SUZ12 in plexiform neurofibromas and ATAD5, EVI2A and C17orf79 in MPNSTs. More interestingly, two genes were significantly downregulated (RNF135 and CENTA2) in tumor Schwann cells from MPNST biopsies and in MPNST cell lines. This study points to the involvement of several genes (particularly RNF135 and CENTA2) in the increased risk of malignancy observed in NF1-microdeleted patients.
Assuntos
Biomarcadores Tumorais/genética , Deleção de Genes , Genes da Neurofibromatose 1 , Neoplasias de Bainha Neural/genética , Proteínas de Transporte/genética , Linhagem Celular Tumoral , Proteínas Ativadoras de GTPase/genética , Perfilação da Expressão Gênica , Regulação Neoplásica da Expressão Gênica , Predisposição Genética para Doença , Humanos , Proteínas de Membrana/genética , MicroRNAs/genética , Fases de Leitura Aberta/genética , Fatores de Risco , Células de Schwann/metabolismo , Ubiquitina-Proteína LigasesRESUMO
PURPOSE: Neurofibromatosis type 1 (NF1) is an autosomal dominant disorder with a complex variety of clinical manifestations. The hallmark of NF1 is the onset of heterogeneous (dermal or plexiform) benign neurofibromas. Plexiform neurofibromas can give rise to malignant peripheral nerve sheath tumors, which are resistant to conventional therapies. EXPERIMENTAL DESIGN: To identify new signaling pathways involved in the malignant transformation of plexiform neurofibromas, we applied a 22,000-oligonucleotide microarray approach to a series of plexiform neurofibromas and malignant peripheral nerve sheath tumors. Changes in the expression of selected genes were then confirmed by real-time quantitative reverse transcription-PCR. RESULTS: We identified two tenascin gene family members that were significantly deregulated in both human NF1-associated tumors and NF1-deficient primary cells: Tenascin C (TNC) was up-regulated whereas tenascin XB (TNXB) was down-regulated during tumor progression. TNC activation is mainly due to the up-regulation of large TNC splice variants. Immunohistochemical studies showed that TNC transcripts are translated into TNC protein in TNC-overexpressing tumors. Aberrant transcriptional activation of TNC seems to be principally mediated by activator protein transcription factor complexes. CONCLUSION: TNXB and TNC may be involved in the malignant transformation of plexiform neurofibromas. Anti-TNC antibodies, already used successfully in clinical trials to treat malignant human gliomas, may be an appropriate new therapeutic strategy for NF1.
Assuntos
Regulação Neoplásica da Expressão Gênica , Neurofibromatose 1/genética , Neurofibromatose 1/patologia , Análise de Sequência com Séries de Oligonucleotídeos/métodos , Tenascina/biossíntese , Processamento Alternativo , Diferenciação Celular , Análise por Conglomerados , Fibroblastos/metabolismo , Humanos , Transdução de Sinais , Resultado do TratamentoAssuntos
Síndrome de Down/diagnóstico , Primeiro Trimestre da Gravidez , Diagnóstico Pré-Natal/métodos , Análise Química do Sangue , Feminino , França , Humanos , Programas de Rastreamento/ética , Programas de Rastreamento/métodos , Programas de Rastreamento/estatística & dados numéricos , Gravidez , Primeiro Trimestre da Gravidez/sangue , Primeiro Trimestre da Gravidez/fisiologia , Diagnóstico Pré-Natal/ética , Diagnóstico Pré-Natal/estatística & dados numéricos , Ultrassonografia Pré-NatalRESUMO
PURPOSE: Neurofibromatosis type 1 (NF1) is an autosomal dominant disorder with a complex variety of clinical symptoms. The hallmark of NF1 is the development of heterogeneous benign neurofibromas, which may appear as dermal neurofibromas or plexiform neurofibromas. NF1 patients with plexiform neurofibromas are at risk of developing malignant peripheral nerve sheath tumors. EXPERIMENTAL DESIGN: To obtain additional insight into the molecular pathogenesis of plexiform neurofibromas, we used real-time quantitative reverse transcription-PCR assays to quantify the mRNA expression of 349 selected genes in plexiform neurofibromas in comparison with dermal neurofibromas and patient-matched malignant peripheral nerve sheath tumors. RESULTS: Thirty genes were significantly up-regulated in plexiform neurofibromas compared with dermal neurofibromas. None were down-regulated. The up-regulated genes mainly encoded transcription factors and growth factors and secreted proteins, cytokines, and their receptors, pointing to a role of paracrine and autocrine signaling defects in the genesis of plexiform neurofibromas. We also identified a gene expression profile, based on MMP9, FLT4/VEGFR3, TNFRSF10B/TRAILR2, SHH, and GLI1, which discriminated those plexiform neurofibromas most likely to undergo malignant transformation. CONCLUSION: Our study has identified a limited number of signaling pathways that could be involved, when altered, in plexiform neurofibroma development. Some of the up-regulated genes could be useful diagnostic or prognostic markers or form the basis of novel therapeutic strategies.
Assuntos
Regulação da Expressão Gênica , Neoplasias de Bainha Neural/genética , Neurofibroma Plexiforme/genética , Neurofibroma/patologia , Neurofibromatose 1/genética , Adolescente , Adulto , Transformação Celular Neoplásica , Primers do DNA/química , Regulação para Baixo , Feminino , Humanos , Masculino , Filogenia , Reação em Cadeia da Polimerase , Prognóstico , RNA/metabolismo , RNA Mensageiro/metabolismo , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Transdução de Sinais , Fatores de Tempo , Regulação para CimaRESUMO
BACKGROUND: Neurofibromatosis type 1 (NF1) is an autosomal dominant disorder with a complex range of clinical symptoms. The hallmark of NF1 is the onset of heterogeneous (dermal or plexiform) benign neurofibromas. Plexiform neurofibromas can give rise to malignant peripheral nerve sheath tumors (MPNSTs), and the underlying molecular mechanisms are largely unknown. RESULTS: To obtain further insight into the molecular pathogenesis of MPNSTs, we used real-time quantitative RT-PCR to quantify the mRNA expression of 489 selected genes in MPNSTs, in comparison with plexiform neurofibromas. The expression of 28 (5.7%) of the 489 genes was significantly different between MPNSTs and plexiform neurofibromas; 16 genes were upregulated and 12 were downregulated in MPNSTs. The altered genes were mainly involved in cell proliferation (MKI67, TOP2A, CCNE2), senescence (TERT, TERC), apoptosis (BIRC5/Survivin, TP73) and extracellular matrix remodeling (MMP13, MMP9, TIMP4, ITGB4). More interestingly, other genes were involved in the Ras signaling pathway (RASSF2, HMMR/RHAMM) and the Hedgehog-Gli signaling pathway (DHH, PTCH2). Several of the down-regulated genes were Schwann cell-specific (L1CAM, MPZ, S100B, SOX10, ERBB3) or mast cell-specific (CMA1, TPSB), pointing to a depletion and/or dedifferentiation of Schwann cells and mast cells during malignant transformation of plexiform neurofibromas. CONCLUSION: These data suggest that a limited number of signaling pathways, and particularly the Hedgehog-Gli signaling pathway, may be involved in malignant transformation of plexiform neurofibromas. Some of the relevant genes or their products warrant further investigation as potential therapeutic targets in NF1.
Assuntos
Sistemas Computacionais , Perfilação da Expressão Gênica/métodos , Regulação Neoplásica da Expressão Gênica/genética , Neoplasias de Bainha Neural/genética , Neurofibromatose 1/genética , Reação em Cadeia da Polimerase Via Transcriptase Reversa/métodos , Adolescente , Adulto , Apoptose/genética , Diferenciação Celular/genética , Proliferação de Células , Regulação para Baixo/genética , Matriz Extracelular/genética , Matriz Extracelular/patologia , Feminino , Genes Neoplásicos/genética , Humanos , Masculino , Mastócitos/química , Mastócitos/metabolismo , Mastócitos/patologia , Pessoa de Meia-Idade , Neurofibroma Plexiforme/genética , RNA Mensageiro/genética , RNA Neoplásico/genética , Células de Schwann/química , Células de Schwann/metabolismo , Células de Schwann/patologia , Transdução de Sinais/genética , Neoplasias Cutâneas/genética , Regulação para Cima/genéticaRESUMO
The hallmark of neurofibromatosis type 1 is the development of dermal and plexiform neurofibromas. Neurofibromatosis type 1 patients with plexiform neurofibromas are at risk of developing malignant peripheral nerve sheath tumors. We applied a 22,000-oligonucleotide microarray transcriptomic approach to a series of plexiform neurofibromas in comparison with dermal neurofibromas, and results were confirmed with real-time quantitative reverse transcription-polymerase chain reaction. Thirteen genes were upregulated and 10 were downregulated in plexiform neurofibromas. The upregulated genes mainly encode molecules involved in cell adhesion, extracellular matrix, fibrogenesis, and angiogenesis. Several CCN gene family members were dysregulated in neurofibromatosis type 1 tumorigenesis; the angiogenic gene CCN1/CYR61 was specifically upregulated in the plexiform neurofibromas; CCN4/WISP1 was upregulated, and CCN3/NOV and CCN5/WISP2 were downregulated in paired comparisons of plexiform neurofibroma and malignant peripheral nerve sheath tumor from the same patients. CCN1 and CCN3 proteins were detected by immunohistochemistry in neurofibromatosis type 1-associated tumors. Upregulation of S100A8, S100A9, and CD36 was also observed and suggests a role of this pathway in inflammation-associated genesis of plexiform neurofibromas. In summary, a limited number of pathways are potentially involved in plexiform neurofibroma development. Some of the genes identified, particularly CCN1, might be useful diagnostic or prognostic markers or form the basis for novel therapeutic strategies.
Assuntos
Regulação Neoplásica da Expressão Gênica , Peptídeos e Proteínas de Sinalização Intercelular/metabolismo , Neurofibroma/genética , Neurofibroma/metabolismo , Neurofibromatose 1/genética , Neoplasias Cutâneas/metabolismo , Adolescente , Adulto , Proteínas de Sinalização Intercelular CCN , Testes de Carcinogenicidade/métodos , Diferenciação Celular/genética , Células Cultivadas , Proteína Rica em Cisteína 61/genética , Proteína Rica em Cisteína 61/metabolismo , Feminino , Perfilação da Expressão Gênica/métodos , Humanos , Peptídeos e Proteínas de Sinalização Intercelular/genética , Peptídeos e Proteínas de Sinalização Intracelular/genética , Peptídeos e Proteínas de Sinalização Intracelular/metabolismo , Masculino , Pessoa de Meia-Idade , Proteína Sobre-Expressa em Nefroblastoma/genética , Proteína Sobre-Expressa em Nefroblastoma/metabolismo , Neurofibroma/patologia , Neurofibromatose 1/metabolismo , Análise de Sequência com Séries de Oligonucleotídeos/métodos , Proteínas Proto-Oncogênicas/genética , Proteínas Proto-Oncogênicas/metabolismo , RNA Mensageiro/metabolismo , Proteínas Repressoras , Células de Schwann/fisiologia , Neoplasias Cutâneas/genética , Estatísticas não Paramétricas , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo , Adulto JovemRESUMO
The stathmin family consists of phosphoproteins highly conserved in vertebrates and thought to be implicated in the development and functional regulation of various organs, most notably the nervous system. This family includes stathmin, SCG10, SCLIP, and RB3, phosphoproteins that are related by structural and functional homologies. They all sequester tubulin and interfere with microtubule dynamics, a property due to their shared stathmin-like domain. Little is known about the expression of the stathmin gene family in humans. Herein, we describe for the first time, for a collection of human tissues, the expression of each member of this family, using real-time quantitative RT-PCR. We found that stathmin is ubiquitously expressed, whereas SCG10 and RB3 are neural enriched, expression patterns similar to those reported for other mammals. Surprisingly, SCLIP, whose expression is thought to be neural-specific, exhibits a broader tissue distribution. Analyses of the SCLIP gene (approved symbol STMN3) show that it contains several NRSE-like elements that display low or no affinity for the cognate binding protein NRSF. The substantial expression of SCLIP in most tissues points out a novel function for this protein outside the nervous system and raises the possibility that its coexpression with stathmin could provide some degree of functional redundancy.