RESUMO
Transgenic expression of the abnormal products of acute myeloid leukemia-associated (AML-associated) primary chromosomal translocations in hematopoietic stem/progenitor cells initiates leukemogenesis in mice, yet additional mutations are needed for leukemia development. We report here aberrant expression of PR domain containing 16 (PRDM16) in AML cells with either translocations of 1p36 or normal karyotype. These carried, respectively, relatively high prevalence of mutations in the TP53 tumor suppressor gene and in the nucleophosmin (NPM) gene, which regulates p53. Two protein isoforms are expressed from PRDM16, which differ in the presence or absence of the PR domain. Overexpression of the short isoform, sPRDM16, in mouse bone marrow induced AML with full penetrance, but only in the absence of p53. The mouse leukemias were characterized by multilineage cellular abnormalities and megakaryocyte dysplasia, a common feature of human AMLs with 1p36 translocations or NPM mutations. Overexpression of sPRDM16 increased the pool of HSCs in vivo, and in vitro blocked myeloid differentiation and prolonged progenitor life span. Loss of p53 augmented the effects of sPRDM16 on stem cell number and induced immortalization of progenitors. Thus, overexpression of sPRDM16 induces abnormal growth of stem cells and progenitors and cooperates with disruption of the p53 pathway in the induction of myeloid leukemia.
Assuntos
Transformação Celular Neoplásica/metabolismo , Proteínas de Ligação a DNA/biossíntese , Células-Tronco Hematopoéticas/metabolismo , Leucemia Mieloide Aguda/metabolismo , Células-Tronco Neoplásicas/metabolismo , Fatores de Transcrição/biossíntese , Proteína Supressora de Tumor p53 , Animais , Medula Óssea/metabolismo , Medula Óssea/patologia , Diferenciação Celular/genética , Transformação Celular Neoplásica/genética , Transformação Celular Neoplásica/patologia , Senescência Celular/genética , Proteínas de Ligação a DNA/genética , Regulação Leucêmica da Expressão Gênica , Células-Tronco Hematopoéticas/patologia , Humanos , Leucemia Mieloide Aguda/genética , Leucemia Mieloide Aguda/patologia , Camundongos , Camundongos Knockout , Células-Tronco Neoplásicas/patologia , Proteínas Nucleares/genética , Proteínas Nucleares/metabolismo , Nucleofosmina , Isoformas de Proteínas/biossíntese , Isoformas de Proteínas/genética , Estrutura Terciária de Proteína/genética , Fatores de Transcrição/genética , Translocação Genética , Proteína Supressora de Tumor p53/genéticaRESUMO
PURPOSE: An overlapping area of gain at 3q26 has been reported in lung squamous cell carcinoma (SCC), but whether this also occurs in preneoplastic/preinvasive squamous cell proliferations and early-stage invasive carcinomas of the lung is still unknown. EXPERIMENTAL DESIGN: We evaluated the prevalence and the clinicopathologic implications of 3q26 amplification and polysomy of chromosome 3 in 31 preneoplastic/preinvasive squamous cell lesions of the bronchial mucosa and in 139 early-stage invasive pulmonary SCC, both of limited growth within the bronchial wall [early hilar SCC (EHSCC)] and involving the pulmonary parenchyma [parenchyma-infiltrating SCC (PISCC)]. Moreover, mRNA expression of two candidate genes (h-TERC and SKI-like), both mapping to the minimal common amplification region, was also studied by quantitative real-time reverse transcription-PCR. RESULTS: 3q26 amplification and polysomy of chromosome 3 were confined to malignant samples, with 37% of invasive SCC, and 27% of severe dysplasias/in situ carcinomas showing these chromosomal abnormalities. Amplification (with minimal common amplification region at 3q26.2), polysomy 3, concurrent amplification and polysomy 3, or other changes (monosomy) were found in 25 SCC and 1 dysplasia, 24 and 2, 2 and 0, and 1 and 0, respectively. Amplification was significantly associated with EHSCC, polysomy 3 with PISCC. 3q26 amplification correlated with increased tumor diameter and a history of smoking, whereas polysomy 3 correlated with tumor diameter, pT class, and p53, p21, and fascin immunoreactivity. No relationship of either 3q26 gain or polysomy was found with patients' survival. Overexpression of h-TERC or SKI-like mRNA was found in 3q26-amplified or polysomic SCC, with higher levels of h-TERC in the former and of SKI-like in the latter. CONCLUSIONS: 3q26 amplification and chromosome 3 polysomy may be related to the development of invasive SCC, with differential distribution in tumor subsets, despite substantial histologic uniformity. Both h-TERC and SKI-like may be involved in tumor progression.
Assuntos
Carcinoma de Células Escamosas/genética , Cromossomos Humanos Par 3/genética , Amplificação de Genes , Neoplasias Pulmonares/genética , Lesões Pré-Cancerosas/genética , Adulto , Idoso , Feminino , Humanos , Hibridização in Situ Fluorescente , Peptídeos e Proteínas de Sinalização Intracelular , Masculino , Pessoa de Meia-Idade , Proteínas Proto-Oncogênicas/biossíntese , RNA/biossíntese , RNA Mensageiro/análise , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Telomerase/biossínteseRESUMO
The RET (REarranged during Transfection) receptor tyrosine kinase is targeted by oncogenic rearrangements in thyroid and lung adenocarcinoma. Recently, a RET (exon 12) rearrangement with FGFR1OP [fibroblast growth factor receptor 1 (FGFR1) oncogene partner] (exon 12) was identified in one chronic myelomonocytic leukemia (CMML) patient. We report the molecular cloning and functional characterization of a novel FGFR1OP (exon 11)-RET (exon 11) gene fusion event (named FGFR1OP-RET), mediated by a reciprocal translocation t(6; 10)(q27; q11), in a patient affected by primary myelofibrosis (PMF) with secondary acute myeloid leukemia (AML). The FGFR1OP-RET fusion protein displayed constitutive tyrosine kinase and transforming activity in NIH3T3 fibroblasts, and induced IL3-independent growth and activation of PI3K/STAT signaling in hematopoietic Ba/F3 cells. FGFR1OP-RET supported cytokine-independent growth, protection from stress and enhanced self-renewal of primary murine hematopoietic progenitor and stem cells in vitro. In vivo, FGFR1OP-RET caused a spectrum of disease phenotypes, with >50% of mice showing a fatal myeloproliferative disorder (MPD). Other phenotypes were leukemia transplantable in secondary recipients, dramatic expansion of the mast cell lineage, and reduction of repopulating activity upon lethal irradiation. In conclusion, FGFR1OP-RET chimeric oncogenes are endowed with leukemogenic potential and associated to myeloid neoplasms (CMML and PMF/AML).
Assuntos
Cromossomos Humanos Par 10 , Cromossomos Humanos Par 6 , Neoplasias Hematológicas , Proteínas de Fusão Oncogênica , Proteínas Proto-Oncogênicas c-ret , Proteínas Proto-Oncogênicas , Translocação Genética , Animais , Cromossomos Humanos Par 10/genética , Cromossomos Humanos Par 10/metabolismo , Cromossomos Humanos Par 6/genética , Cromossomos Humanos Par 6/metabolismo , Neoplasias Hematológicas/genética , Neoplasias Hematológicas/metabolismo , Neoplasias Hematológicas/patologia , Humanos , Leucemia Mielogênica Crônica BCR-ABL Positiva , Camundongos , Células NIH 3T3 , Proteínas de Fusão Oncogênica/genética , Proteínas de Fusão Oncogênica/metabolismo , Proteínas Proto-Oncogênicas/genética , Proteínas Proto-Oncogênicas/metabolismo , Proteínas Proto-Oncogênicas c-ret/genética , Proteínas Proto-Oncogênicas c-ret/metabolismoRESUMO
BACKGROUND: Little is known about the dual role of RAS-association domain family 1 (RASSF1) gene at 3p21.3 in neuroendocrine tumors (NET) of the lung. MATERIALS AND METHODS: Twenty typical carcinoids (TC), 11 atypical carcinoids (ATC), 11 large cell neuroendocrine carcinomas (LCNEC) and 16 small cell lung carcinomas (SCLC) were analyzed for RASSF1 promoter methylation, mRNA and protein expression, and loss of 3p21.3 locus. RESULTS: Promoter 1 was hypermethylated in NET but not in paired non-neoplastic lung tissues nor in 20 control NSCLC, with the degree of hypermethylation paralleling tumor grade. RASSF1 A/E isoform mRNA but not protein expression was lost in most NET compared to NSCLC or non-neoplastic tissues. The relationship between methylation level and mRNA or protein loss varied by NET type, with significant correlation for decreasing RASSF1 A protein in ACT, and marginal correlation for down-regulated RASSF 1 A/E mRNA in TC, this suggesting a non linear regulation by methylation in NET. No promoter 2 methylation was detected in NET; however, up-regulation of its RASSF1 C transcript emerged as an adverse prognostic factor in the LCNEC/SCLC group. A correlation was found between 3p21.3 allelic loss and decrease of RASSF1 A/E mRNA (p=0.023) and protein (p=0.043) expression in ATC, suggesting that 3p21.3 allelic loss contributed to the loss of gene expression. CONCLUSION: RASSF1 A/E is likely to act as a tumor suppressor gene in most pulmonary NET, and RASSF1 C as an oncogene in high-grade tumors.
Assuntos
Neoplasias Pulmonares/genética , Tumores Neuroendócrinos/genética , Proteínas Supressoras de Tumor/genética , Adenocarcinoma/genética , Idoso , Carcinoma de Células Pequenas/genética , Carcinoma de Células Escamosas/genética , Metilação de DNA , Feminino , Genes Supressores de Tumor , Humanos , Hibridização in Situ Fluorescente , Perda de Heterozigosidade , Masculino , Pessoa de Meia-Idade , Oncogenes , Regiões Promotoras Genéticas , RNA Mensageiro/biossíntese , RNA Mensageiro/genética , Proteínas Supressoras de Tumor/biossínteseRESUMO
We performed a whole-genome loss of heterozygosity (LOH) analysis of 32 cases of acute myeloid leukemia with normal karyotype using high-density single nucleotide polymorphism arrays. LOH was found in 20% of cases. We identified two types of LOH: (i) interstitial, characterized by small deletions of genomic DNA (2-8 Mb), and (ii) terminal, involving large (30-90 Mb) telomeric regions. Surprisingly, terminal LOH occurred without loss of genetic material because of deletion of large chromosome regions and their substitution through the duplication of the corresponding regions from the homologous chromosomes (acquired partial uniparental disomy).
Assuntos
Aberrações Cromossômicas , Genoma Humano , Leucemia Mieloide/genética , Perda de Heterozigosidade , Polimorfismo de Nucleotídeo Único/genética , Doença Aguda , DNA de Neoplasias/genética , DNA de Neoplasias/metabolismo , Humanos , Hibridização in Situ Fluorescente , Cariotipagem , Telômero/genéticaRESUMO
8p11 myeloproliferative syndrome (EMS) is a clinical-pathologic entity characterized by rearrangements involving the FGFR1 gene, which encodes a receptor tyrosine kinase. These rearrangements invariably lead to aberrant fusion proteins in which the kinase activity is constitutively turned on, with resulting oncogenic properties. In this article, we describe a new translocation in EMS, t(7;8)(q34;p11), in which the FGFR1 gene is fused to a previously unidentified partner, the TIF1 gene. We show that both the TIF1-FGFR1 and FGFR1-TIF1 fusion proteins have the potential to be translated as a result of the translocation. Thus, our data extend the involvement of FGFR1 in EMS and lend support to the concept that there is a precise correlation between genotype and phenotype in this disease.
Assuntos
Proteínas de Transporte/genética , Cromossomos Humanos Par 7/genética , Cromossomos Humanos Par 8/genética , Transtornos Mieloproliferativos/genética , Cadeias Pesadas de Miosina/genética , Proteínas de Fusão Oncogênica/genética , Receptores Proteína Tirosina Quinases/genética , Receptores de Fatores de Crescimento de Fibroblastos/genética , Translocação Genética/genética , Apoptose/genética , Proteínas Reguladoras de Apoptose , Sequência de Bases , Feminino , Genótipo , Humanos , Pessoa de Meia-Idade , Dados de Sequência Molecular , Proteínas Nucleares , Fenótipo , Receptor Tipo 1 de Fator de Crescimento de Fibroblastos , SíndromeRESUMO
BACKGROUND AND OBJECTIVES: The ETV6 gene undergoes rearrangements with tyrosine kinases in hematologic malignancies and solid tumors. ETV6/ABL1 chimeric proteins have been detected both in lymphoid and myeloid disorders. Our objective was to study two new cases of ETV6/ABL1-positive acute myeloid leukemia (AML) and to focus on bone marrow morphology and on molecular cytogenetics of eosinophilic cells. DESIGN AND METHODS: Fluorescence in situ hybridization (FISH) was performed in two AML cases with different translocations, i.e. t(8;12)(p21;p13) and t(9;12) (q34; p13). We used probes for the short arm of chromosome 12, for ABL1 and BCR, for centromeric regions, and for whole chromosome arms. Polymerase chain reaction (PCR) was carried out by applying primers selected for the ETV6 gene. RESULTS: In both cases, bone marrow morphology was characterized by trilineage dysplasia and increased abnormal eosinophils. FISH showed the 5'ETV6 translocated to chromosome 8 in patient #1, and to chromosome 9 in patient #2. A 3' PCR identified chimeric products resulting from fusion between ETV6 exon 4 or exon 5, and ABL1 exon 2. Accordingly, an ETV6/ABL1 fusion signal was detected on der(8) in patient #1, and on der(9) in patient #2. Using interphase FISH abnormal bone marrow eosinophils were proved to belong to the neoplastic clone, carrying the ETV6 rearrangement. INTERPRETATION AND CONCLUSIONS: Our findings provide new information on the heterogeneity of conventional cytogenetics in ETV6/ABL1 positive leukemias, and indicate the putative target cell in this AML is an immature precursor capable of terminally differentiating towards eosinophils.
Assuntos
Cromossomos Humanos Par 12/genética , Eosinofilia/patologia , Eosinófilos/patologia , Leucemia Mieloide Aguda/sangue , Proteínas de Fusão Oncogênica/genética , Translocação Genética/genética , Adulto , Anemia Refratária com Excesso de Blastos/complicações , Medula Óssea/patologia , Linhagem da Célula , Aberrações Cromossômicas , Cromossomos Humanos Par 12/ultraestrutura , Cromossomos Humanos Par 8/genética , Cromossomos Humanos Par 8/ultraestrutura , Cromossomos Humanos Par 9/genética , Cromossomos Humanos Par 9/ultraestrutura , Células Clonais/enzimologia , Células Clonais/patologia , Eosinofilia/etiologia , Eosinofilia/genética , Eosinófilos/enzimologia , Genes abl , Heterogeneidade Genética , Humanos , Hibridização in Situ Fluorescente , Cariotipagem , Leucemia Mieloide Aguda/complicações , Leucemia Mieloide Aguda/genética , Masculino , Pessoa de Meia-Idade , Células-Tronco Neoplásicas/enzimologia , Células-Tronco Neoplásicas/patologia , Proteínas de Fusão Oncogênica/fisiologia , Proteínas Tirosina Quinases , RNA Mensageiro/genética , RNA Neoplásico/genéticaRESUMO
The chimeric gene NUP98/HOXC13 was detected in a patient with a de novo acute myeloid leukemia and a t(11;12)(p15;q13). Fluorescence in situ hybridization with PAC1173K1 identified the breakpoint on 11p15, indicating that the NUP98 gene was involved in the translocation. At 12q13, the breakpoint fell within BAC 578A18, selected for the homeobox C (HOXC) cluster genes. RACE-PCR showed that HOXC13 was the partner gene of NUP98. To date, HOXC13 is the eighth homeobox gene that, as the result of a reciprocal translocation, fuses with NUP98 in myeloid malignancies.
Assuntos
Leucemia Mieloide Aguda/genética , Proteínas de Fusão Oncogênica/genética , Evolução Fatal , Feminino , Humanos , Leucemia Mieloide Aguda/diagnóstico , Leucemia Mieloide Aguda/tratamento farmacológico , Pessoa de Meia-Idade , Recidiva Local de Neoplasia/genética , Segunda Neoplasia Primária/genéticaRESUMO
A new complex rearrangement involving chromosome bands 5q13, 12p13, 22q11, and 3q12 was identified and characterized in a patient with acute myeloid leukemia. Fluorescence in situ hybridization showed the involvement of the ETV6 gene in 12p13. ETV6 primers were specifically designed for 3'- and 5'-RACE-PCR experiments, which led to the identification of the other two rearranged genes. The derivative chromosome 5 harbored a fusion of the ETV6 sequence with that of the LOC115548 gene. The two genes were placed in opposite orientation and did not encode a fusion protein. On the derivative chromosome 12, ETV6 was fused to the MN1 gene on chromosome 22. Also in this case, the insertion, within the MN1 sequence, of a portion of chromosome 3 prevented the formation of a fusion protein. Finally, the derivative chromosome 22 contained the 3' portions of both LOC115548 and MN1, and no fusion transcript with coding potential could be predicted. In conclusion, all chromosome breakpoints led to the truncation of the three involved genes in the absence of predicted fusion proteins. This study lends further support to the hypothesis that gene disruption resulting in either loss of function or haploinsufficiency may be relevant in acute myeloid leukemia pathogenesis.