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1.
Eur J Haematol ; 88(2): 136-43, 2012 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-21933280

RESUMO

OBJECTIVES: Acquired trisomy 21 is one of the most common numerical abnormalities in acute myeloid leukemia (AML), myelodysplastic syndrome (MDS), myeloproliferative neoplasms (MPN), and MDS/MPN; however, little is known about its pathogenic impact, accompanying submicroscopic changes, and its relation to other clinical features. Furthermore, previous studies addressing this issue have mainly focused on cases in which +21 was part of a complex karyotype. METHODS: We ascertained the incidence of +21, both as a sole change (T21s) and irrespective of additional changes (T21all), in relation to disease type, morphologic subgroup, gender, and age in all published AML, MDS, MPN, and MDS/MPN cases. Furthermore, single nucleotide polymorphism (SNP) array analysis was performed on 11 myeloid malignancies with T21s, followed by mutation analysis of the FGFR1, FLT3, GATA1, JAK2, KIT, NPM1, NRAS, RUNX1, and TET2 genes. RESULTS: The frequencies of T21s and/or T21all varied significantly among the AML, MDS, MPN, and MDS/MPN cases, among the AML and MPN subtypes, and in relation to the age of the AML, MDS, and MPN patients. In the 11 cases analyzed by SNP array, a total of nine genomic imbalances, comprising seven deletions and two duplications, were identified in six cases; none of the alterations were recurrent. Partial uniparental disomies (UPDs) were found in five cases; two recurrent UPDs were identified, namely UPD4q and UPD7q. Mutations in NPM1, RUNX1, and TET2 were detected in five cases, three of which harbored a pathogenic RUNX1 mutation. The TET2 mutation was found in one of the cases with UPD4q. CONCLUSIONS: The results show that trisomy 21-positive myeloid malignancies are clinically highly variable and that they display a heterogeneous pattern of copy number alterations and mutations.


Assuntos
Cromossomos Humanos Par 21 , Variações do Número de Cópias de DNA , Leucemia Mieloide/genética , Mutação , Síndromes Mielodisplásicas/genética , Trissomia , Adolescente , Adulto , Idoso , Criança , Pré-Escolar , Feminino , Humanos , Cariótipo , Masculino , Pessoa de Meia-Idade , Nucleofosmina , Polimorfismo de Nucleotídeo Único , Adulto Jovem
2.
Proc Natl Acad Sci U S A ; 107(37): 16280-5, 2010 Sep 14.
Artigo em Inglês | MEDLINE | ID: mdl-20805474

RESUMO

Chronic myeloid leukemia (CML) is genetically characterized by the Philadelphia (Ph) chromosome, formed through a reciprocal translocation between chromosomes 9 and 22 and giving rise to the constitutively active tyrosine kinase P210 BCR/ABL1. Therapeutic strategies aiming for a cure of CML will require full eradication of Ph chromosome-positive (Ph(+)) CML stem cells. Here we used gene-expression profiling to identify IL-1 receptor accessory protein (IL1RAP) as up-regulated in CML CD34(+) cells and also in cord blood CD34(+) cells as a consequence of retroviral BCR/ABL1 expression. To test whether IL1RAP expression distinguishes normal (Ph(-)) and leukemic (Ph(+)) cells within the CML CD34(+)CD38(-) cell compartment, we established a unique protocol for conducting FISH on small numbers of sorted cells. By using this method, we sorted cells directly into drops on slides to investigate their Ph-chromosome status. Interestingly, we found that the CML CD34(+)CD38(-)IL1RAP(+) cells were Ph(+), whereas CML CD34(+)CD38(-)IL1RAP(-) cells were almost exclusively Ph(-). By performing long-term culture-initiating cell assays on the two cell populations, we found that Ph(+) and Ph(-) candidate CML stem cells could be prospectively separated. In addition, by generating an anti-IL1RAP antibody, we provide proof of concept that IL1RAP can be used as a target on CML CD34(+)CD38(-) cells to induce antibody-dependent cell-mediated cytotoxicity. This study thus identifies IL1RAP as a unique cell surface biomarker distinguishing Ph(+) from Ph(-) candidate CML stem cells and opens up a previously unexplored avenue for therapy of CML.


Assuntos
Anticorpos/imunologia , Apoptose , Proteína Acessória do Receptor de Interleucina-1/metabolismo , Leucemia Mielogênica Crônica BCR-ABL Positiva/imunologia , Leucemia Mielogênica Crônica BCR-ABL Positiva/patologia , Células-Tronco Neoplásicas/metabolismo , ADP-Ribosil Ciclase 1/imunologia , Antígenos CD34/imunologia , Separação Celular , Proteínas de Fusão bcr-abl/metabolismo , Perfilação da Expressão Gênica , Regulação Neoplásica da Expressão Gênica , Humanos , Proteína Acessória do Receptor de Interleucina-1/imunologia , Leucemia Mielogênica Crônica BCR-ABL Positiva/genética , Glicoproteínas de Membrana/imunologia , Células-Tronco Neoplásicas/citologia , Células-Tronco Neoplásicas/imunologia
3.
Blood ; 116(12): 2103-11, 2010 Sep 23.
Artigo em Inglês | MEDLINE | ID: mdl-20554971

RESUMO

The 8p11 myeloproliferative syndrome (EMS), also referred to as stem cell leukemia/lymphoma, is a chronic myeloproliferative disorder that rapidly progresses into acute leukemia. Molecularly, EMS is characterized by fusion of various partner genes to the FGFR1 gene, resulting in constitutive activation of the tyrosine kinases in FGFR1. To date, no previous study has addressed the functional consequences of ectopic FGFR1 expression in the potentially most relevant cellular context, that of normal primary human hematopoietic cells. Herein, we report that expression of ZMYM2/FGFR1 (previously known as ZNF198/FGFR1) or BCR/FGFR1 in normal human CD34(+) cells from umbilical-cord blood leads to increased cellular proliferation and differentiation toward the erythroid lineage in vitro. In immunodeficient mice, expression of ZMYM2/FGFR1 or BCR/FGFR1 in human cells induces several features of human EMS, including expansion of several myeloid cell lineages and accumulation of blasts in bone marrow. Moreover, bone marrow fibrosis together with increased extramedullary hematopoiesis is observed. This study suggests that FGFR1 fusion oncogenes, by themselves, are capable of initiating an EMS-like disorder, and provides the first humanized model of a myeloproliferative disorder transforming into acute leukemia in mice. The established in vivo EMS model should provide a valuable tool for future studies of this disorder.


Assuntos
Cromossomos Humanos Par 8 , Modelos Animais de Doenças , Transtornos Mieloproliferativos/genética , Animais , Proteínas de Ligação a DNA/genética , Humanos , Camundongos , Camundongos SCID , Camundongos Transgênicos , Transtornos Mieloproliferativos/patologia , Proteínas de Fusão Oncogênica , Mielofibrose Primária , Proteínas Proto-Oncogênicas c-bcr/genética , Receptor Tipo 1 de Fator de Crescimento de Fibroblastos/genética , Fatores de Transcrição/genética
4.
Cancer Genet Cytogenet ; 199(2): 89-95, 2010 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-20471511

RESUMO

Despite the recent success of tyrosine kinase inhibitors (TKIs) in the treatment of chronic myeloid leukemia (CML), approximately 2-17% of patients develop clonal cytogenetic changes in the Philadelphia-negative (Ph(-)) cell population. A fraction of these patients, in particular those displaying trisomy 8 or monosomy 7, are at risk of developing a myelodysplastic syndrome (MDS) or acute myeloid leukemia (AML). Consequently, there is a need to characterize the clinical features of such cases and to increase our understanding of the pathogenetic mechanisms underlying the emergence of clonal cytogenetic changes in Ph(-) cells. To date, most cases reported have received treatment with imatinib. Here we describe the case of a patient with CML who developed monosomy 7 in Ph(-) cells during dasatinib therapy. At 20 months after dasatinib initiation, the patient developed MDS, which rapidly progressed into AML. Genome-wide 500K SNP array analysis of the monosomy 7 clone revealed no acquired submicroscopic copy number changes. Given the strong association between monosomy 7 and mutation of genes involved in the RAS pathway in juvenile myelomonocytic leukemia, we also screened for pathogenetic variants in KRAS, NRAS, and PTPN11, but did not detect any changes.


Assuntos
Cromossomos Humanos Par 7/genética , Leucemia Mielogênica Crônica BCR-ABL Positiva/genética , Leucemia Mieloide Aguda/genética , Leucemia Mieloide Crônica Atípica BCR-ABL Negativa/genética , Monossomia , Pirimidinas/uso terapêutico , Tiazóis/uso terapêutico , Dasatinibe , Feminino , Genes ras/genética , Humanos , Hibridização in Situ Fluorescente , Cariotipagem , Leucemia Mielogênica Crônica BCR-ABL Positiva/tratamento farmacológico , Leucemia Mielogênica Crônica BCR-ABL Positiva/patologia , Leucemia Mieloide Aguda/induzido quimicamente , Leucemia Mieloide Aguda/patologia , Leucemia Mieloide Crônica Atípica BCR-ABL Negativa/induzido quimicamente , Leucemia Mieloide Crônica Atípica BCR-ABL Negativa/patologia , Pessoa de Meia-Idade , Mutação/genética , Síndromes Mielodisplásicas/induzido quimicamente , Síndromes Mielodisplásicas/genética , Síndromes Mielodisplásicas/patologia , Análise de Sequência com Séries de Oligonucleotídeos , Polimorfismo de Nucleotídeo Único , Prognóstico , Inibidores de Proteínas Quinases/uso terapêutico , Proteína Tirosina Fosfatase não Receptora Tipo 11/genética , Proteínas Proto-Oncogênicas/genética , Proteínas Proto-Oncogênicas p21(ras) , Proteínas ras/genética
5.
Exp Hematol ; 37(3): 367-75, 2009 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-19135771

RESUMO

OBJECTIVE: The P190 and P210 BCR/ABL1 fusion genes are mainly associated with different types of hematologic malignancies, but it is presently unclear whether they are functionally different following expression in primitive human hematopoietic cells. MATERIALS AND METHODS: We investigated and systematically compared the effects of retroviral P190 BCR/ABL1 and P210 BCR/ABL1 expression on cell proliferation, differentiation, and global gene expression in human CD34(+) cells from cord blood. RESULTS: Expression of either P190 BCR/ABL1 or P210 BCR/ABL1 resulted in expansion of erythroid cells and stimulated erythropoietin-independent burst-forming unit-erythroid colony formation. By using a lentiviral anti-signal transducer and activator of transcription 5 (STAT5) short-hairpin RNA, we found that both P190 BCR/ABL1- and P210 BCR/ABL1-induced erythroid cell expansion were STAT5-dependent. Under in vitro conditions favoring B-cell differentiation, neither P190 nor P210 BCR/ABL1-expressing cells formed detectable levels of CD19-positive cells. Gene expression profiling revealed that P190 BCR/ABL1 and P210 BCR/ABL1 induced almost identical gene expression profiles. CONCLUSIONS: Our data suggest that the early cellular and transcriptional effects of P190 BCR/ABL1 and P210 BCR/ABL1 expression are very similar when they are expressed in the same human progenitor cell population, and that STAT5 is an important regulator of BCR/ABL1-induced erythroid cell expansion.


Assuntos
Antígenos CD34 , Células Eritroides/citologia , Proteínas de Fusão bcr-abl/fisiologia , Células-Tronco Hematopoéticas/citologia , Fator de Transcrição STAT5/fisiologia , Diferenciação Celular , Linhagem da Célula , Proliferação de Células , Sangue Fetal/citologia , Proteínas de Fusão bcr-abl/genética , Perfilação da Expressão Gênica , Humanos , Transdução Genética
6.
Br J Haematol ; 144(4): 546-51, 2009 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-19055661

RESUMO

The t(X;7)(q22;q34), a translocation not previously reported in a neoplastic disorder, was identified and molecularly characterised in a paediatric T-cell acute lymphoblastic leukaemia (T-ALL), subsequently shown also to harbour a deletion of 6q, a STIL/TAL1 fusion and an activating NOTCH1 mutation. The t(X;7) was further investigated using fluorescence in situ hybridisation (FISH), real-time quantitative polymerase chain reaction (RQ-PCR) and Western blot analyses. FISH revealed a breakpoint at the T-cell receptor beta locus at 7q34 and mapped the corresponding breakpoint to Xq22.3. The latter region contains only two known genes, namely insulin receptor substrate 4 (IRS4) and collagen, type IV, alpha 5 (COL4A5), the expressions of which were analysed by the use of RQ-PCR. COL4A5 was not differentially expressed in the t(X;7)-positive sample compared to five T-ALL controls. However, a marked, 1000-fold overexpression of IRS4 was identified. Western blot analysis with a monoclonal antibody against IRS4 showed overexpression also at the protein level. Considering that forced expression of several members of the IRS family has been shown to result in increased cell proliferation, for example in haematopoietic cells, we hypothesise that the IRS4 up-regulation in T-ALL is pathogenetically important as a mitogenic stimulus.


Assuntos
Cromossomos Humanos Par 7/genética , Cromossomos Humanos X/genética , Proteínas Substratos do Receptor de Insulina/genética , Leucemia-Linfoma Linfoblástico de Células T Precursoras/genética , Translocação Genética , Criança , Regulação Neoplásica da Expressão Gênica , Humanos , Hibridização in Situ Fluorescente , Proteínas Substratos do Receptor de Insulina/biossíntese , Masculino , Receptores de Antígenos de Linfócitos T alfa-beta/genética , Recombinação Genética , Regulação para Cima
7.
Genes Chromosomes Cancer ; 47(4): 267-75, 2008 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-18181176

RESUMO

Philadelphia (Ph) chromosome-positive leukemia is characterized by the BCR/ABL1 fusion protein that affects a wide range of signal transduction pathways. The knowledge about its downstream target genes is, however, still quite limited. To identify novel BCR/ABL1-regulated genes we used global gene expression profiling of several Ph-positive and Ph-negative cell lines treated with imatinib. Following imatinib treatment, the Ph-positive cells showed decreased growth, viability, and reduced phosphorylation of BCR/ABL1 and STAT5. In total, 142 genes were identified as being dependent on BCR/ABL1-mediated signaling, mainly including genes involved in signal transduction, e.g. the JAK/STAT, MAPK, TGFB, and insulin signaling pathways, and in regulation of metabolism. Interestingly, BCR/ABL1 was found to activate several genes involved in negative feedback regulation (CISH, SOCS2, SOCS3, PIM1, DUSP6, and TNFAIP3), which may act to indirectly suppress the tumor promoting effects exerted by BCR/ABL1. In addition, several genes identified as deregulated upon BCR/ABL1 expression could be assigned to the TGFB and NFkB signaling pathways, as well as to reflect the metabolic adjustments needed for rapidly growing cells. Apart from providing important pathogenetic insights into BCR/ABL1-mediated leukemogenesis, the present study also provides a number of pathways/individual genes that may provide attractive targets for future development of targeted therapies. This article contains Supplementary Material available at http://www.interscience.wiley.com/jpages/1045-2257/suppmat.


Assuntos
Biomarcadores Tumorais/genética , Retroalimentação Fisiológica , Proteínas de Fusão bcr-abl/genética , Regulação Leucêmica da Expressão Gênica/fisiologia , Leucemia Mielogênica Crônica BCR-ABL Positiva/genética , Leucemia Mieloide Crônica Atípica BCR-ABL Negativa/genética , Benzamidas , Biomarcadores Tumorais/metabolismo , Northern Blotting , Western Blotting , Proteínas de Fusão bcr-abl/metabolismo , Perfilação da Expressão Gênica/métodos , Humanos , Mesilato de Imatinib , Leucemia Mielogênica Crônica BCR-ABL Positiva/tratamento farmacológico , Leucemia Mielogênica Crônica BCR-ABL Positiva/patologia , Leucemia Mieloide Crônica Atípica BCR-ABL Negativa/tratamento farmacológico , Leucemia Mieloide Crônica Atípica BCR-ABL Negativa/patologia , Análise de Sequência com Séries de Oligonucleotídeos , Cromossomo Filadélfia , Piperazinas/uso terapêutico , Inibidores de Proteínas Quinases/uso terapêutico , Proteínas Tirosina Quinases/antagonistas & inibidores , Pirimidinas/uso terapêutico , Transdução de Sinais , Transcrição Gênica , Células Tumorais Cultivadas
8.
Genes Chromosomes Cancer ; 47(1): 64-70, 2008 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-17943971

RESUMO

During 1995-2004, 209 children/adolescents were diagnosed with acute lymphoblastic or myeloid leukemia (ALL, AML) in Southern Sweden, of which 177 (85%), comprising 128 B-lineage ALL, 34 AML, and 15 T-cell ALL, could be analyzed for internal tandem duplications (ITD) and activating point mutations in the second tyrosine kinase domain (ATKD) of FLT3. Seventeen (10%) FLT3 mutations (6 ITD, 11 ATKD; mutually exclusive) were detected. None of the T-cell ALL harbored any mutations. ITD and ATKD were found in 2% and 6% of the B-lineage ALL and in 12% and 9% of the AML, being particularly common in high hyperdiploid ALL (14%), ALL (20%), and AML (23%) with 11q23/MLL rearrangements, and in AML with a normal karyotype (60%). All ATKD-positive AML with MLL rearrangements harbored the t(9;11)(p21;q23). Global gene expression data were available for 76 of the B-lineage ALL and 19 of the AML, of which 6 (8%) and 3 (16%) had FLT3 mutations, respectively. No distinct expression pattern associated with FLT3 mutations was identified.


Assuntos
Regulação Leucêmica da Expressão Gênica/fisiologia , Leucemia Mieloide Aguda/genética , Mutação , Leucemia-Linfoma Linfoblástico de Células Precursoras/genética , Tirosina Quinase 3 Semelhante a fms/genética , Adolescente , Fatores Etários , Criança , Pré-Escolar , Feminino , Frequência do Gene , Humanos , Lactente , Recém-Nascido , Leucemia Mieloide Aguda/enzimologia , Masculino , Leucemia-Linfoma Linfoblástico de Células Precursoras/enzimologia
9.
Genes Chromosomes Cancer ; 46(7): 635-43, 2007 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-17394134

RESUMO

The 8p11 myeloproliferative syndrome (EMS) is a chronic myeloproliferative disorder molecularly characterized by fusion of various 5' partner genes to the 3' part of the fibroblast growth factor receptor 1 (FGFR1) gene at 8p, resulting in constitutive activation of the tyrosine kinase activity contained within FGFR1. EMS is associated with a high risk of transformation to acute myeloid leukemia (AML), but the mechanisms underlying the disease progression are unknown. In the present study, we have investigated a case of EMS harboring a t(8;22)(p11;q11)/BCR-FGFR1 rearrangement as well as a t(9;21)(q34;q22) at the time of AML transformation. FISH and RT-PCR analyses revealed that the t(9;21) leads to a fusion gene consisting of the 5' part of RUNX1 (exons 1-4) fused to repetitive sequences of a gene with unknown function on chromosome 9, adding 70 amino acids to RUNX1 exon 4. The t(9;21) hence results in a truncation of RUNX1. No point mutations were found in the other RUNX1 allele. The most likely functional outcome of the rearrangement was haploinsufficiency of RUNX1, which thus may be one mechanism by which EMS transforms to AML.


Assuntos
Cromossomos Humanos Par 8 , Subunidade alfa 2 de Fator de Ligação ao Core/genética , Fusão Gênica , Transtornos Mieloproliferativos/genética , Idoso , Sequência de Aminoácidos , Sequência de Bases , Northern Blotting , Southern Blotting , DNA Complementar , Progressão da Doença , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Dados de Sequência Molecular , Reação em Cadeia da Polimerase Via Transcriptase Reversa
10.
Eur J Haematol ; 77(1): 27-34, 2006 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-16548914

RESUMO

OBJECTIVES: The t(12;14)(p13;q11)--a recurrent translocation in childhood T-cell acute lymphoblastic leukemia (T-ALL)--has very recently been molecularly characterized in one case, which displayed overexpression of the cyclin D2 gene (CCND2). PATIENTS AND METHODS: We have characterized two pediatric t(12;14)-positive T-ALLs using fluorescence in situ hybridization (FISH), cDNA microarray, and real-time polymerase chain reaction (PCR). RESULTS: FISH revealed breakpoints (BPs) in the T-cell receptor alpha/delta locus (14q11) and in the vicinity of the CCND2 gene at 12p13. To investigate the expression of genes in 12p13, cDNA microarray analysis was performed. Expression data for eight genes, including CCND2, surrounding the 12p BP were compared with those in other T-ALLs. The t(12;14)-positive T-ALL displayed an increased expression of CCND2 compared to the controls, whereas the expression of the other genes was similar in all T-ALLs. Expression of CCND2 and two additional genes (PARP11 and FGF23), close to the 12p BP, was investigated with real-time PCR of the two t(12;14)-positive cases and four controls. Neither PARP11 nor FGF23 displayed expression differences among the T-ALLs, whereas CCND2 was clearly overexpressed in both t(12;14)-positive cases as compared to the mean expression level in the controls. CONCLUSION: We have confirmed, in two additional cases, that the recurrent T-ALL-associated t(12;14) results in overexpression of cyclin D2. The t(12;14) is the first neoplasia-associated translocation shown to result in overexpression of cyclin D2. Furthermore, it is the first example of a T-cell neoplasm with a targeted deregulation of a member of a cyclin-encoding gene family.


Assuntos
Ciclinas/genética , Regulação Neoplásica da Expressão Gênica , Leucemia-Linfoma Linfoblástico de Células Precursoras/genética , Receptores de Antígenos de Linfócitos T alfa-beta/genética , Receptores de Antígenos de Linfócitos T gama-delta/genética , Translocação Genética , Adolescente , Cromossomos Humanos Par 12 , Cromossomos Humanos Par 14 , Ciclina D2 , Ciclinas/metabolismo , Feminino , Fator de Crescimento de Fibroblastos 23 , Humanos , Hibridização in Situ Fluorescente , Lactente , Masculino , Reação em Cadeia da Polimerase , Receptores de Antígenos de Linfócitos T alfa-beta/metabolismo , Receptores de Antígenos de Linfócitos T gama-delta/metabolismo
11.
Proc Natl Acad Sci U S A ; 102(52): 19069-74, 2005 Dec 27.
Artigo em Inglês | MEDLINE | ID: mdl-16354839

RESUMO

Global expression profiles of a consecutive series of 121 childhood acute leukemias (87 B lineage acute lymphoblastic leukemias, 11 T cell acute lymphoblastic leukemias, and 23 acute myeloid leukemias), six normal bone marrows, and 10 normal hematopoietic subpopulations of different lineages and maturations were ascertained by using 27K cDNA microarrays. Unsupervised analyses revealed segregation according to lineages and primary genetic changes, i.e., TCF3(E2A)/PBX1, IGH@/MYC, ETV6(TEL)/RUNX1(AML1), 11q23/MLL, and hyperdiploidy (>50 chromosomes). Supervised discriminatory analyses were used to identify differentially expressed genes correlating with lineage and primary genetic change. The gene-expression profiles of normal hematopoietic cells were also studied. By using principal component analyses (PCA), a differentiation axis was exposed, reflecting lineages and maturation stages of normal hematopoietic cells. By applying the three principal components obtained from PCA of the normal cells on the leukemic samples, similarities between malignant and normal cell lineages and maturations were investigated. Apart from showing that leukemias segregate according to lineage and genetic subtype, we provide an extensive study of the genes correlating with primary genetic changes. We also investigated the expression pattern of these genes in normal hematopoietic cells of different lineages and maturations, identifying genes preferentially expressed by the leukemic cells, suggesting an ectopic activation of a large number of genes, likely to reflect regulatory networks of pathogenetic importance that also may provide attractive targets for future directed therapies.


Assuntos
Regulação Neoplásica da Expressão Gênica , Leucemia/genética , Medula Óssea/metabolismo , Células da Medula Óssea/citologia , Linhagem Celular , Linhagem da Célula , Aberrações Cromossômicas , Análise por Conglomerados , DNA Complementar/metabolismo , Regulação da Expressão Gênica , Genes Neoplásicos , Hematopoese , Células-Tronco Hematopoéticas/citologia , Sistema Hematopoético/metabolismo , Humanos , Leucemia/metabolismo , Leucemia Mieloide Aguda/genética , Modelos Genéticos , Proteína de Leucina Linfoide-Mieloide , Análise de Sequência com Séries de Oligonucleotídeos , Ploidias , Leucemia-Linfoma Linfoblástico de Células Precursoras/genética , Análise de Componente Principal , Fatores de Transcrição/química
12.
Hum Mol Genet ; 13(14): 1479-85, 2004 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-15163636

RESUMO

Double minutes (dmin), the cytogenetic hallmark of genomic amplification, are found in approximately 1% of karyotypically abnormal acute myeloid leukemias (AML) and myelodysplastic syndromes (MDS). The MYC gene at 8q24 has been reported to be amplified in the majority of the cases, and generally it has been assumed that MYC is the target gene. However, only a few studies have focused on the extent of the amplicon or on the expression patterns of the amplified genes. We have studied six cases (five AML and one MDS) with MYC-containing dmin. Detailed fluorescence in situ hybridization analyses identified a common 4.3 Mb amplicon, with clustered proximal and distal breakpoints, harboring eight known genes (C8FW, NSE2, POU5FLC20, MYC, PVT1, AK093424, MGC27434 and MLZE). The corresponding region was deleted in one of the chromosome 8 homologues in five of the six cases, suggesting that the dmin originated through extra replication (or loop-formation)--excision--amplification. Northern blot analysis revealed that MYC was not overexpressed. Instead, the C8FW gene, encoding a phosphoprotein regulated by mitogenic pathways, displayed increased expression. These results exclude MYC as the target gene and indicate that overexpression of C8FW may be the functionally important consequence of 8q24 amplicons in AML and MDS.


Assuntos
Cromatina/genética , Amplificação de Genes , Genes myc , Síndromes Mielodisplásicas/genética , Fosfoproteínas/genética , Doença Aguda , Idoso , Northern Blotting , Cromossomos Humanos Par 8 , Feminino , Humanos , Hibridização in Situ Fluorescente , Leucemia Mieloide/genética , Masculino , Fosfoproteínas/biossíntese
13.
Exp Hematol ; 32(5): 476-82, 2004 May.
Artigo em Inglês | MEDLINE | ID: mdl-15145216

RESUMO

OBJECTIVE: The t(9;22) translocation is associated with more than 95% of cases of chronic myeloid leukemia. The resulting fusion of the BCR and ABL1 loci produces the constitutively active BCR/ABL1 tyrosine kinase. A wide range of signal transduction molecules are activated by BCR/ABL1, including MYC, PI-3 kinase, and different STAT molecules. In contrast, relatively few genes are known to be regulated by BCR/ABL1 at the level of transcription. MATERIALS AND METHODS: In an effort to better understand the transcriptional program activated by BCR/ABL1, we used cDNA microarrays to evaluate the relative expression of approximately 6450 human genes in U937 myelomonocytic cells expressing P210 BCR/ABL1 via a tetracycline-inducible promoter. RESULTS: We confirmed the previously reported up-regulation of the PIM1 and JUN oncogenes by BCR/ABL1. In addition, we identified 59 more genes up-regulated by BCR/ABL1. Interestingly, roughly one third of these were genes previously reported to be interferon (IFN)-responsive, including the OAS1, IFIT1, IFI16, ISGF3G, and STAT1 genes. An additional seven BCR/ABL1-regulated genes were found to be IFN-responsive in U937 cells. The expression profile also included genes encoding transcription factors, kinases, and signal transduction molecules, as well as genes regulating cell growth, differentiation, apoptosis, and cell adhesion, features previously suggested to be affected by BCR/ABL1. CONCLUSION: These observations shed novel insight into the mechanism of BCR/ABL1 action and provide a range of targets for further investigation.


Assuntos
Análise de Sequência com Séries de Oligonucleotídeos , Proteínas Tirosina Quinases/fisiologia , Regulação para Cima , Proteínas de Fusão bcr-abl , Perfilação da Expressão Gênica/métodos , Regulação Neoplásica da Expressão Gênica , Vetores Genéticos , Humanos , Regiões Promotoras Genéticas/efeitos dos fármacos , Proteínas Tirosina Quinases/genética , Tetraciclina/farmacologia , Transfecção , Células U937
14.
Eur J Haematol ; 72(5): 307-13, 2004 May.
Artigo em Inglês | MEDLINE | ID: mdl-15059064

RESUMO

BACKGROUND: The FLT3 gene is frequently mutated in acute myeloid leukemia (AML), either by an internal tandem duplication (ITD) of the juxtamembrane domain or by activating point mutations in the second tyrosine kinase domain (ATKD). Only a few investigations have focused on the prognostic significance of FLT3 alterations in AML among the elderly, yielding conflicting results. In the present study, the frequency and clinical relevance of FLT3 abnormalities were ascertained in a cohort of elderly AML patients. PATIENTS AND METHODS: A total of 109 AMLs, occurring in patients above the age of 60 yr (median 71.5), were investigated. DNA was extracted from fresh bone marrow cells or from cells in fixative and investigated for the presence of ITD of exons 14 and 15 and the ATKD D835 in exon 20. RESULTS: ITDs and ATKDs were identified in 20 (18%) and 11 (10%) of the cases, respectively. Three cases displayed both an ITD and an ATKD. FLT3 abnormalities were associated with leukocytosis (ITD P < 0.01; ATKD P = 0.069), and the monocytic FAB subtypes M4 and M5 [ITD (P < 0.05), ATKD (P = 0.05)], and ITD and ATKD were significantly (P < 0.05) more common in cases with a normal karyotype. There was no correlation between the presence of FLT3 abnormalities and complete remission rates or overall survival. CONCLUSION: A correlation was observed between FLT3 abnormalities and leukocytosis, a normal karyotype, and the M4/M5 subtypes of leukemia. However, no clear-cut prognostic impact of FLT3 abnormalities was identified in elderly AML patients.


Assuntos
Leucemia Mieloide/genética , Proteínas de Neoplasias/genética , Mutação Puntual , Proteínas Proto-Oncogênicas/genética , Receptores Proteína Tirosina Quinases/genética , Sequências de Repetição em Tandem , Doença Aguda , Idoso , DNA de Neoplasias/genética , Éxons/genética , Feminino , Humanos , Corpos de Inclusão/ultraestrutura , Leucemia Monocítica Aguda/genética , Leucemia Mieloide/patologia , Leucemia Mielomonocítica Aguda/genética , Contagem de Leucócitos , Masculino , Pessoa de Meia-Idade , Prognóstico , Análise de Sobrevida , Tirosina Quinase 3 Semelhante a fms
15.
Br J Haematol ; 122(1): 85-93, 2003 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-12823349

RESUMO

Most chronic myeloid leukaemia (CML) patients are genetically characterized by the t(9;22)(q34;q11), generating the BCR/ABL1 fusion gene. However, a few CML patients with rearrangements of 9q34 and 12p13, leading to ETV6/ABL1 chimaeras, have also been reported. Here we describe the clinical and genetic response to imatinib mesylate treatment of an ETV6/ABL1-positive CML patient diagnosed in blast crisis (BC). A chronic phase was achieved after acute myeloid leukaemia induction therapy. Then, treatment with imatinib mesylate (600 mg/d) was initiated and the effect was assessed clinically as well as genetically, including by repeated interphase fluorescence in situ hybridization studies. Until d 71 of imatinib mesylate therapy, stable improvements in the clinical and laboratory features were noted, and the frequency of ABL1-rearranged peripheral blood cells decreased from 56% to 11%. At d 92, an additional t(12;13)(p12;q13), with the 12p breakpoint proximal to ETV6, was found. The patient relapsed into BC 126 d after the start of the imatinib mesylate treatment and succumbed to the disease shortly afterwards. No mutations in the tyrosine kinase domain of ABL1 of the ETV6/ABL1 fusion were identified in the second BC. However, whereas the ETV6/ABL1 expression was seemingly the same at diagnosis and at second BC, the expression of ETV6 was markedly lower at the second BC. This decreased expression of wild-type ETV6 may have been a contributory factor for the relapse.


Assuntos
Antineoplásicos/uso terapêutico , Crise Blástica/genética , Leucemia Mielogênica Crônica BCR-ABL Positiva/genética , Proteínas de Fusão Oncogênica/genética , Piperazinas/uso terapêutico , Pirimidinas/uso terapêutico , Adulto , Benzamidas , Crise Blástica/tratamento farmacológico , Inibidores Enzimáticos/uso terapêutico , Evolução Fatal , Seguimentos , Humanos , Mesilato de Imatinib , Hibridização in Situ Fluorescente/métodos , Leucemia Mielogênica Crônica BCR-ABL Positiva/tratamento farmacológico , Leucemia Mielogênica Crônica BCR-ABL Positiva/patologia , Masculino , Proteínas Tirosina Quinases/antagonistas & inibidores , Recidiva
16.
Cancer Res ; 63(6): 1202-6, 2003 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-12649177

RESUMO

The pathogenetic role of the P210 BCR/ABL1 fusion gene in the chronic phase of chronic myeloid leukemia (CML) has been well established.In contrast, the genetic mechanisms underlying the disease progression into the accelerated phase (AP) and the final blast crisis (BC) remain poorly understood. We have previously identified (A. Barbouti et al., Genes Chromosomes Cancer, 35: 127-137, 2002) two cryptic balanced translocations, t(7;17)(p15;q23) and t(7;17)(q32-34;q23), in CML AP/BC using multicolor fluorescence in situ hybridization. In this study, we show that a novel gene in 17q23, Musashi-2 (MSI2), encoding a putative RNA-binding protein, is rearranged in both cases and that a MSI2/HOXA9 fusion gene is formed in the case with the 7p15 breakpoint. The identified in-frame MSI2/HOXA9 fusion transcript retains both of the RNA recognition motif domains of MSI2, which is fused to the homeobox domain of HOXA9, and is likely to play an important role in the disease progression of CML.


Assuntos
Cromossomos Humanos Par 15/genética , Cromossomos Humanos Par 7/genética , Proteínas de Homeodomínio/genética , Leucemia Mielogênica Crônica BCR-ABL Positiva/genética , Proteínas de Fusão Oncogênica/genética , Proteínas de Ligação a RNA/genética , Adulto , Sequência de Aminoácidos , Sequência de Bases , Progressão da Doença , Feminino , Ordem dos Genes , Humanos , Hibridização in Situ Fluorescente , Leucemia Mielogênica Crônica BCR-ABL Positiva/patologia , Pessoa de Meia-Idade , Dados de Sequência Molecular , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Translocação Genética
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