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2.
Cancer Discov ; 8(12): 1614-1631, 2018 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-30266814

RESUMO

: Deletion of chromosome 6q is a well-recognized abnormality found in poor-prognosis T-cell acute lymphoblastic leukemia (T-ALL). Using integrated genomic approaches, we identified two candidate haploinsufficient genes contiguous at 6q14, SYNCRIP (encoding hnRNP-Q) and SNHG5 (that hosts snoRNAs), both involved in regulating RNA maturation and translation. Combined silencing of both genes, but not of either gene alone, accelerated leukemogeneis in a Tal1/Lmo1/Notch1-driven mouse model, demonstrating the tumor-suppressive nature of the two-gene region. Proteomic and translational profiling of cells in which we engineered a short 6q deletion by CRISPR/Cas9 genome editing indicated decreased ribosome and mitochondrial activities, suggesting that the resulting metabolic changes may regulate tumor progression. Indeed, xenograft experiments showed an increased leukemia-initiating cell activity of primary human leukemic cells upon coextinction of SYNCRIP and SNHG5. Our findings not only elucidate the nature of 6q deletion but also highlight the role of ribosomes and mitochondria in T-ALL tumor progression. SIGNIFICANCE: The oncogenic role of 6q deletion in T-ALL has remained elusive since this chromosomal abnormality was first identified more than 40 years ago. We combined genomic analysis and functional models to show that the codeletion of two contiguous genes at 6q14 enhances malignancy through deregulation of a ribosome-mitochondria axis, suggesting the potential for therapeutic intervention.This article is highlighted in the In This Issue feature, p. 1494.

3.
Oncotarget ; 6(34): 36269-77, 2015 Nov 03.
Artigo em Inglês | MEDLINE | ID: mdl-26474455

RESUMO

Little is known about inherited factors associated with the risk of developing chronic myelogenous leukemia (CML). We used a dedicated DNA chip containing 16 561 single nucleotide polymorphisms (SNPs) covering 1 916 candidate genes to analyze 437 CML patients and 1 144 healthy control individuals. Single SNP association analysis identified 139 SNPs that passed multiple comparisons (1% false discovery rate). The HDAC9, AVEN, SEMA3C, IKBKB, GSTA3, RIPK1 and FGF2 genes were each represented by three SNPs, the PSM family by four SNPs and the SLC15A1 gene by six. Haplotype analysis showed that certain combinations of rare alleles of these genes increased the risk of developing CML by more than two or three-fold. A classification tree model identified five SNPs belonging to the genes PSMB10, TNFRSF10D, PSMB2, PPARD and CYP26B1, which were associated with CML predisposition. A CML-risk-allele score was created using these five SNPs. This score was accurate for discriminating CML status (AUC: 0.61, 95%CI: 0.58-0.64). Interestingly, the score was associated with age at diagnosis and the average number of risk alleles was significantly higher in younger patients. The risk-allele score showed the same distribution in the general population (HapMap CEU samples) as in our control individuals and was associated with differential gene expression patterns of two genes (VAPA and TDRKH). In conclusion, we describe haplotypes and a genetic score that are significantly associated with a predisposition to develop CML. The SNPs identified will also serve to drive fundamental research on the putative role of these genes in CML development.


Assuntos
Leucemia Mielogênica Crônica BCR-ABL Positiva/genética , Feminino , Predisposição Genética para Doença , Humanos , Masculino , Pessoa de Meia-Idade , Polimorfismo de Nucleotídeo Único
4.
J Immunol ; 195(6): 2580-90, 2015 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-26246143

RESUMO

Acute myeloid leukemia (AML) is a heterogeneous group of malignancies that may be sensitive to the NK cell antitumor response. However, NK cells are frequently defective in AML. In this study, we found in an exploratory cohort (n = 46) that NK cell status at diagnosis of AML separated patients in two groups with a different clinical outcome. Patients with a deficient NK cell profile, including reduced expression of some activating NK receptors (e.g., DNAX accessory molecule-1, NKp46, and NKG2D) and decreased IFN-γ production, had a significantly higher risk of relapse (p = 0.03) independently of cytogenetic classification in multivariate analysis. Patients with defective NK cells showed a profound gene expression decrease in AML blasts for cytokine and chemokine signaling (e.g., IL15, IFNGR1, IFNGR2, and CXCR4), Ag processing (e.g., HLA-DRA, HLA-DRB1, and CD74) and adhesion molecule pathways (e.g., PVR and ICAM1). A set of 388 leukemic classifier genes defined in the exploratory cohort was independently validated in a multicentric cohort of 194 AML patients. In total, these data evidenced the interplay between NK cells and AML blasts at diagnosis allowing an immune-based stratification of AML patients independently of clinical classifications.


Assuntos
Citotoxicidade Imunológica/imunologia , Células Matadoras Naturais/imunologia , Leucemia Mieloide Aguda/imunologia , Receptores de Células Matadoras Naturais/metabolismo , Evasão Tumoral/imunologia , Adulto , Idoso , Antígenos CD/imunologia , Moléculas de Adesão Celular/imunologia , Feminino , Cadeias alfa de HLA-DR/imunologia , Cadeias HLA-DRB1/imunologia , Humanos , Interferon gama/biossíntese , Interleucina-15/biossíntese , Leucemia Mieloide Aguda/diagnóstico , Masculino , Pessoa de Meia-Idade , Receptores CXCR4/biossíntese , Receptores de Interferon/biossíntese , Sialiltransferases/imunologia , Evasão Tumoral/genética , Adulto Jovem
5.
Blood ; 123(7): 1021-31, 2014 Feb 13.
Artigo em Inglês | MEDLINE | ID: mdl-24335234

RESUMO

SAMHD1 is a deoxynucleoside triphosphate triphosphohydrolase and a nuclease that restricts HIV-1 in noncycling cells. Germ-line mutations in SAMHD1 have been described in patients with Aicardi-Goutières syndrome (AGS), a congenital autoimmune disease. In a previous longitudinal whole genome sequencing study of chronic lymphocytic leukemia (CLL), we revealed a SAMHD1 mutation as a potential founding event. Here, we describe an AGS patient carrying a pathogenic germ-line SAMHD1 mutation who developed CLL at 24 years of age. Using clinical trial samples, we show that acquired SAMHD1 mutations are associated with high variant allele frequency and reduced SAMHD1 expression and occur in 11% of relapsed/refractory CLL patients. We provide evidence that SAMHD1 regulates cell proliferation and survival and engages in specific protein interactions in response to DNA damage. We propose that SAMHD1 may have a function in DNA repair and that the presence of SAMHD1 mutations in CLL promotes leukemia development.


Assuntos
Dano ao DNA/genética , Mutação em Linhagem Germinativa , Leucemia Linfocítica Crônica de Células B/genética , Proteínas Monoméricas de Ligação ao GTP/genética , Adulto , Doenças Autoimunes do Sistema Nervoso/complicações , Doenças Autoimunes do Sistema Nervoso/genética , Estudos de Coortes , Hibridização Genômica Comparativa , Frequência do Gene , Células HeLa , Humanos , Leucemia Linfocítica Crônica de Células B/complicações , Masculino , Malformações do Sistema Nervoso/complicações , Malformações do Sistema Nervoso/genética , Proteína 1 com Domínio SAM e Domínio HD , Adulto Jovem
6.
Oncotarget ; 4(10): 1582-91, 2013 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-24123600

RESUMO

Pharmacogenetic studies in chronic myelogenous leukemia (CML) typically use a candidate gene approach. In an alternative strategy, we analyzed the impact of single nucleotide polymorphisms (SNPs) in drug transporter genes on the molecular response to imatinib, using a DNA chip containing 857 SNPs covering 94 drug transporter genes. Two cohorts of CML patients treated with imatinib were evaluated: an exploratory cohort including 105 patients treated at 400 mg/d and a validation cohort including patients sampled from the 400 mg/d and 600 mg/d arms of the prospective SPIRIT trial (n=239). Twelve SNPs discriminating patients according to cumulative incidence of major molecular response (CI-MMR) were identified within the exploratory cohort. Three of them, all located within the ABCG2 gene, were validated in patients included in the 400 mg/d arm of the SPIRIT trial. We identified an ABCG2 haplotype (define as G-G, rs12505410 and rs2725252) as associated with significantly higher CI-MMR in patients treated at 400 mg/d. Interestingly, we found that patients carrying this ABCG2 "favorable" haplotype in the 400 mg arm reached similar CI-MMR rates that patients randomized in the imatinib 600 mg/d arm. Our results suggest that response to imatinib may be influenced by constitutive haplotypes in drug transporter genes. Lower response rates associated with "non- favorable" ABCG2 haplotypes may be overcome by increasing the imatinib daily dose up to 600 mg/d.


Assuntos
Transportadores de Cassetes de Ligação de ATP/genética , Antineoplásicos/administração & dosagem , Benzamidas/administração & dosagem , Leucemia Mielogênica Crônica BCR-ABL Positiva/tratamento farmacológico , Leucemia Mielogênica Crônica BCR-ABL Positiva/genética , Proteínas de Neoplasias/genética , Piperazinas/administração & dosagem , Pirimidinas/administração & dosagem , Membro 2 da Subfamília G de Transportadores de Cassetes de Ligação de ATP , Estudos de Coortes , DNA de Neoplasias/sangue , DNA de Neoplasias/genética , Feminino , Genótipo , Haplótipos , Humanos , Mesilato de Imatinib , Leucemia Mielogênica Crônica BCR-ABL Positiva/sangue , Masculino , Pessoa de Meia-Idade , Análise de Sequência com Séries de Oligonucleotídeos , Farmacogenética , Polimorfismo de Nucleotídeo Único , Estudos Prospectivos , Estudos Retrospectivos , Resultado do Tratamento
7.
J Clin Invest ; 123(9): 3797-801, 2013 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-23979160

RESUMO

Tumor cells with donor genotype have been identified in human skin cancer after allogeneic transplantation; however, the donor contribution to the malignant epithelium has not been established. Kidney transplant recipients have an increased risk of invasive skin squamous cell carcinoma (SCC), which is associated with accumulation of the tumor suppressor p53 and TP53 mutations. In 21 skin SCCs from kidney transplant recipients, we systematically assessed p53 expression and donor/recipient origin in laser-microdissected p53+ tumor cells. In one patient, molecular analyses demonstrated that skin tumor cells had the donor genotype and harbored a TP53 mutation in codon 175. In a kidney graft biopsy performed 7 years before the skin SCC diagnosis, we found p53+ cells in the renal tubules. We identified the same TP53 mutation in these p53+ epithelial cells from the kidney transplant. These findings provide evidence for a donor epithelial cell contribution to the malignant skin epithelium in the recipient in the setting of allogeneic kidney transplantation. This finding has theoretical implications for cancer initiation and progression and clinical implications in the context of prolonged immunosuppression and longer survival of kidney transplant patients.


Assuntos
Carcinoma de Células Escamosas/etiologia , Transplante de Rim/efeitos adversos , Neoplasias Cutâneas/etiologia , Substituição de Aminoácidos , Sequência de Bases , Carcinoma de Células Escamosas/metabolismo , Carcinoma de Células Escamosas/patologia , Análise Mutacional de DNA , DNA Mitocondrial/genética , Células Epiteliais/metabolismo , Humanos , Transplante de Rim/patologia , Túbulos Renais/patologia , Microdissecção e Captura a Laser , Repetições de Microssatélites , Neoplasias Cutâneas/metabolismo , Neoplasias Cutâneas/patologia , Transplante Homólogo , Proteína Supressora de Tumor p53/genética , Proteína Supressora de Tumor p53/metabolismo
8.
J Immunol ; 190(12): 6187-97, 2013 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-23690469

RESUMO

In this study, we identify transmembrane protein 131-like (TMEM131L) as a novel regulator of thymocyte proliferation and demonstrate that it corresponds to a not as yet reported inhibitor of Wnt signaling. Short hairpin RNA-mediated silencing of TMEM131L in human CD34(+) hematopoietic progenitors, which were then grafted in NOD-SCID/IL-2rγ(null) mice, resulted in both thymocyte hyperproliferation and multiple pre- and post-ß-selection intrathymic developmental defects. Consistent with deregulated Wnt signaling, TMEM131L-deficient thymocytes expressed Wnt target genes at abnormally high levels, and they displayed both constitutive phosphorylation of Wnt coreceptor LRP6 and ß-catenin intranuclear accumulation. Using T cell factor reporter assays, we found that membrane-associated TMEM131L inhibited canonical Wnt/ß-catenin signaling at the LRP6 coreceptor level. Whereas membrane-associated TMEM131L did not affect LRP6 expression under basal conditions, it triggered lysosome-dependent degradation of its active phosphorylated form following Wnt activation. Genetic mapping showed that phosphorylated LRP6 degradation did not depend on TMEM131L cytoplasmic part but rather on a conserved extracellular domain proximal to the membrane. Collectively, these data indicate that, during thymopoiesis, stage-specific surface translocation of TMEM131L may regulate immature single-positive thymocyte proliferation arrest by acting through mixed Wnt-dependent and -independent mechanisms.


Assuntos
Proliferação de Células , Proteínas de Membrana/metabolismo , Timócitos/citologia , Via de Sinalização Wnt/fisiologia , Animais , Citometria de Fluxo , Células HEK293 , Humanos , Proteínas de Membrana/imunologia , Camundongos , Camundongos Endogâmicos NOD , Camundongos SCID , Microscopia de Fluorescência , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Timócitos/imunologia
9.
Sci Transl Med ; 4(130): 130fs7, 2012 Apr 18.
Artigo em Inglês | MEDLINE | ID: mdl-22517881

RESUMO

A single mouse Lgr5-positive colon stem cell can be expanded into a three-dimensional organoid that, after transplant, contributes to the repair of injured colon epithelia in a mouse model of colitis.


Assuntos
Colo/citologia , Células-Tronco/citologia , Animais , Colite/terapia , Camundongos , Organoides/citologia , Transplante de Células-Tronco , Células-Tronco/fisiologia
10.
J Biol Chem ; 287(21): 17065-76, 2012 May 18.
Artigo em Inglês | MEDLINE | ID: mdl-22457358

RESUMO

The role and the mechanisms by which ß1 integrins regulate the survival and chemoresistance of T cell acute lymphoblastic leukemia (T-ALL) still are poorly addressed. In this study, we demonstrate in T-ALL cell lines and primary blasts, that engagement of α2ß1 integrin with its ligand collagen I (ColI), reduces doxorubicin-induced apoptosis, whereas fibronectin (Fn) had no effect. ColI but not Fn inhibited doxorubicin-induced mitochondrial depolarization, cytochrome c release, and activation of caspase-9 and -3. ColI but not Fn also prevented doxorubicin from down-regulating the levels of the prosurvival Bcl-2 protein family member Mcl-1. The effect of ColI on Mcl-1 occurred through the inhibition of doxorubicin-induced activation of c-Jun N-terminal kinase (JNK). Mcl-1 knockdown experiments showed that the maintenance of Mcl-1 levels is essential for ColI-mediated T-ALL cell survival. Furthermore, activation of MAPK/ERK, but not PI3K/AKT, is required for ColI-mediated inhibition of doxorubicin-induced JNK activation and apoptosis and for ColI-mediated maintenance of Mcl-1 levels. Thus, our study identifies α2ß1 integrin as an important survival pathway in drug-induced apoptosis of T-ALL cells and suggests that its activation can contribute to the generation of drug resistance.


Assuntos
Antibióticos Antineoplásicos/farmacologia , Doxorrubicina/farmacologia , Resistencia a Medicamentos Antineoplásicos , MAP Quinases Reguladas por Sinal Extracelular/metabolismo , Integrina alfa2beta1/metabolismo , Leucemia-Linfoma Linfoblástico de Células T Precursoras/metabolismo , Caspase 3/genética , Caspase 3/metabolismo , Caspase 9/genética , Caspase 9/metabolismo , Colágeno Tipo I/genética , Colágeno Tipo I/metabolismo , Citocromos c/genética , Citocromos c/metabolismo , Ativação Enzimática/genética , MAP Quinases Reguladas por Sinal Extracelular/genética , Feminino , Fibronectinas/genética , Fibronectinas/metabolismo , Técnicas de Silenciamento de Genes , Humanos , Integrina alfa2beta1/genética , Proteínas Quinases JNK Ativadas por Mitógeno/genética , Proteínas Quinases JNK Ativadas por Mitógeno/metabolismo , Células Jurkat , Sistema de Sinalização das MAP Quinases/genética , Masculino , Proteína de Sequência 1 de Leucemia de Células Mieloides , Fosfatidilinositol 3-Quinases/genética , Fosfatidilinositol 3-Quinases/metabolismo , Leucemia-Linfoma Linfoblástico de Células T Precursoras/genética , Leucemia-Linfoma Linfoblástico de Células T Precursoras/patologia , Proteínas Proto-Oncogênicas c-akt/genética , Proteínas Proto-Oncogênicas c-akt/metabolismo , Proteínas Proto-Oncogênicas c-bcl-2/genética , Proteínas Proto-Oncogênicas c-bcl-2/metabolismo
11.
Blood ; 118(7): 1784-96, 2011 Aug 18.
Artigo em Inglês | MEDLINE | ID: mdl-21715312

RESUMO

The mechanisms regulating the emergence of BM prothymocytes remain poorly characterized. Genome-wide transcriptome analyses looking for genes expressed in human prothymocytes led to the identification of AF1q/MLLT11 as a candidate gene conceivably involved in this process. Analysis of AF1q protein subcellular localization and intracellular trafficking showed that despite pronounced karyophily, it was subjected to constitutive nuclear export followed by ubiquitin-mediated degradation in the centrosomal area. Using in vitro assays based on either forced expression or shRNA-mediated silencing of AF1q, we provide evidence that the protein promotes T- over B-cell differentiation in multipotent hematopoietic progenitors. At the molecular level, AF1q confers to multipotent progenitors an increased susceptibility to Delta-like/Notch-mediated signaling. Consistent with these findings, enforced AF1q expression in humanized mice fosters the emergence of BM CD34(+)CD7(+) prothymocytes, enhances subsequent thymus colonization, and accelerates intrathymic T-cell development. In contrast, AF1q silencing provokes a global shift of BM lymphopoiesis toward the B-cell lineage, hinders prothymocyte development, inhibits thymus colonization, and leads to intrathymic accumulation of B cells. Our results indicate that AF1q cooperates with the Notch signaling pathway to foster the emergence of BM prothymocytes and drive subsequent intrathymic specification toward the T-cell lineage.


Assuntos
Células-Tronco Hematopoéticas/citologia , Linfopoese , Proteínas de Neoplasias/metabolismo , Proteínas Proto-Oncogênicas/metabolismo , Receptores Notch/metabolismo , Linfócitos T/citologia , Transporte Ativo do Núcleo Celular , Sequência de Aminoácidos , Animais , Linfócitos B/citologia , Linfócitos B/metabolismo , Células Cultivadas , Inativação Gênica , Células HeLa , Células-Tronco Hematopoéticas/metabolismo , Humanos , Camundongos , Camundongos SCID , Dados de Sequência Molecular , Proteínas de Neoplasias/genética , Complexo de Endopeptidases do Proteassoma/metabolismo , Proteínas Proto-Oncogênicas/genética , Alinhamento de Sequência , Transdução de Sinais , Linfócitos T/metabolismo
12.
Blood ; 117(26): 7090-8, 2011 Jun 30.
Artigo em Inglês | MEDLINE | ID: mdl-21551237

RESUMO

We have recently reported inactivation of the tyrosine phosphatase PTPN2 (also known as TC-PTP) through deletion of the entire gene locus in ∼ 6% of T-cell acute lymphoblastic leukemia (T-ALL) cases. T-ALL is an aggressive disease of the thymocytes characterized by the stepwise accumulation of chromosomal abnormalities and gene mutations. In the present study, we confirmed the strong association of the PTPN2 deletion with TLX1 and NUP214-ABL1 expression. In addition, we found cooperation between PTPN2 deletion and activating JAK1 gene mutations. Activating mutations in JAK1 kinase occur in ∼ 10% of human T-ALL cases, and aberrant kinase activity has been shown to confer proliferation and survival advantages. Our results reveal that some JAK1 mutation-positive T-ALLs harbor deletions of the tyrosine phosphatase PTPN2, a known negative regulator of the JAK/STAT pathway. We provide evidence that down-regulation of Ptpn2 sensitizes lymphoid cells to JAK1-mediated transformation and reduces their sensitivity to JAK inhibition.


Assuntos
Regulação Leucêmica da Expressão Gênica , Janus Quinase 1/metabolismo , Leucemia-Linfoma Linfoblástico de Células T Precursoras/metabolismo , Proteína Tirosina Fosfatase não Receptora Tipo 2/metabolismo , Linfócitos T/metabolismo , Adulto , Linhagem Celular , Proliferação de Células/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Transformação Celular Neoplásica , Criança , Hibridização Genômica Comparativa , Feminino , Deleção de Genes , Inativação Gênica , Proteínas de Homeodomínio/genética , Proteínas de Homeodomínio/metabolismo , Humanos , Janus Quinase 1/antagonistas & inibidores , Janus Quinase 1/química , Janus Quinase 1/genética , Masculino , Pessoa de Meia-Idade , Proteínas Mutantes/antagonistas & inibidores , Proteínas Mutantes/química , Proteínas Mutantes/genética , Proteínas Mutantes/metabolismo , Proteínas de Fusão Oncogênica/genética , Proteínas de Fusão Oncogênica/metabolismo , Leucemia-Linfoma Linfoblástico de Células T Precursoras/tratamento farmacológico , Leucemia-Linfoma Linfoblástico de Células T Precursoras/genética , Inibidores de Proteínas Quinases/farmacologia , Proteína Tirosina Fosfatase não Receptora Tipo 2/antagonistas & inibidores , Proteína Tirosina Fosfatase não Receptora Tipo 2/química , Proteína Tirosina Fosfatase não Receptora Tipo 2/genética , Proteínas Proto-Oncogênicas/genética , Proteínas Proto-Oncogênicas/metabolismo , RNA Interferente Pequeno , Adulto Jovem
13.
Cancer Cell ; 19(4): 484-97, 2011 Apr 12.
Artigo em Inglês | MEDLINE | ID: mdl-21481790

RESUMO

To identify oncogenic pathways in T cell acute lymphoblastic leukemia (T-ALL), we combined expression profiling of 117 pediatric patient samples and detailed molecular-cytogenetic analyses including the Chromosome Conformation Capture on Chip (4C) method. Two T-ALL subtypes were identified that lacked rearrangements of known oncogenes. One subtype associated with cortical arrest, expression of cell cycle genes, and ectopic NKX2-1 or NKX2-2 expression for which rearrangements were identified. The second subtype associated with immature T cell development and high expression of the MEF2C transcription factor as consequence of rearrangements of MEF2C, transcription factors that target MEF2C, or MEF2C-associated cofactors. We propose NKX2-1, NKX2-2, and MEF2C as T-ALL oncogenes that are activated by various rearrangements.


Assuntos
Genoma Humano , Proteínas de Homeodomínio/genética , Proteínas de Domínio MADS/genética , Fatores de Regulação Miogênica/genética , Proteínas Nucleares/genética , Oncogenes , Leucemia-Linfoma Linfoblástico de Células T Precursoras/genética , Fatores de Transcrição/genética , Transcrição Genética , Adolescente , Proliferação de Células , Criança , Pré-Escolar , Análise por Conglomerados , Feminino , Regulação Leucêmica da Expressão Gênica , Rearranjo Gênico , Proteínas de Homeodomínio/fisiologia , Humanos , Lactente , Proteínas de Domínio MADS/fisiologia , Fatores de Transcrição MEF2 , Masculino , Fatores de Regulação Miogênica/fisiologia , Proteínas Nucleares/fisiologia , Leucemia-Linfoma Linfoblástico de Células T Precursoras/etiologia , Leucemia-Linfoma Linfoblástico de Células T Precursoras/patologia , Fator Nuclear 1 de Tireoide , Fatores de Transcrição/fisiologia
14.
J Exp Med ; 208(4): 653-61, 2011 Apr 11.
Artigo em Inglês | MEDLINE | ID: mdl-21464223

RESUMO

Genomic studies in human acute lymphoblastic leukemia (ALL) have revealed clonal heterogeneity at diagnosis and clonal evolution at relapse. In this study, we used genome-wide profiling to compare human T cell ALL samples at the time of diagnosis and after engraftment (xenograft) into immunodeficient recipient mice. Compared with paired diagnosis samples, the xenograft leukemia often contained additional genomic lesions in established human oncogenes and/or tumor suppressor genes. Mimicking such genomic lesions by short hairpin RNA-mediated knockdown in diagnosis samples conferred a selective advantage in competitive engraftment experiments, demonstrating that additional lesions can be drivers of increased leukemia-initiating activity. In addition, the xenograft leukemias appeared to arise from minor subclones existing in the patient at diagnosis. Comparison of paired diagnosis and relapse samples showed that, with regard to genetic lesions, xenograft leukemias more frequently more closely resembled relapse samples than bulk diagnosis samples. Moreover, a cell cycle- and mitosis-associated gene expression signature was present in xenograft and relapse samples, and xenograft leukemia exhibited diminished sensitivity to drugs. Thus, the establishment of human leukemia in immunodeficient mice selects and expands a more aggressive malignancy, recapitulating the process of relapse in patients. These findings may contribute to the design of novel strategies to prevent or treat relapse.


Assuntos
Leucemia-Linfoma Linfoblástico de Células T Precursoras/genética , Animais , Ciclo Celular , Perfilação da Expressão Gênica , Humanos , Camundongos , Mitose , Transplante de Neoplasias , PTEN Fosfo-Hidrolase/fisiologia , Leucemia-Linfoma Linfoblástico de Células T Precursoras/patologia , Recidiva , Transplante Heterólogo
15.
Haematologica ; 96(5): 664-71, 2011 May.
Artigo em Inglês | MEDLINE | ID: mdl-21330326

RESUMO

BACKGROUND: Molecular monitoring of chronic myeloid leukemia patients treated with tyrosine kinase inhibitors is essential for therapeutic stratification. Inter-laboratory reproducibility is, therefore, a crucial issue which requires standardization and strict alignment of BCR-ABL1 values to the international scale. An automated cartridge-based assay (Xpert BCR-ABL Monitor(™), Cepheid) had been proposed as a robust alternative to non-automated assays. This study aimed to compare inter-laboratory reproducibility of automated and non-automated quantification, the possibility of converting automated results to the international scale, and the potential economic impact of automation. DESIGN AND METHODS: One hundred and eighteen blood samples from chronic myeloid leukemia patients treated with tyrosine kinase inhibitors were prospectively analyzed in two laboratories using both automated and non-automated assays. The economic evaluation involved a micro-costing study and average costs were assessed as a function of sample throughput. RESULTS: Automated assays achieved similar inter-laboratory reproducibility to highly standardized non-automated assays and a short delay (≤6 h) between sampling and blood lysis had a positive impact on inter-laboratory reproducibility. Reporting automated BCR-ABL1 ratios on the international scale was possible using a specific conversion factor which may vary with batches. Cost assessment showed that automated assays could be relevant for annual activity levels below 300 since average costs were lower than those of the non-automated assays. CONCLUSIONS: The Xpert BCR-ABL Monitor(™) assay could be appropriately used in a near-patient setting for routine quantification of e13/e14-a2 transcripts, preferably in partnership with a regional reference laboratory. However, its prognostic impact relative to non-automated quantification remains to be tested prospectively within appropriate clinical trials.


Assuntos
Técnicas de Laboratório Clínico/normas , Proteínas de Fusão bcr-abl/genética , Leucemia Mielogênica Crônica BCR-ABL Positiva/genética , RNA Mensageiro/metabolismo , Técnicas de Laboratório Clínico/economia , Técnicas de Laboratório Clínico/métodos , Custos e Análise de Custo , Humanos , Leucemia Mielogênica Crônica BCR-ABL Positiva/diagnóstico , Leucemia Mielogênica Crônica BCR-ABL Positiva/tratamento farmacológico , Estudos Prospectivos , Inibidores de Proteínas Quinases/uso terapêutico , RNA Mensageiro/genética , Padrões de Referência , Reprodutibilidade dos Testes , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Sensibilidade e Especificidade
16.
Blood ; 117(15): e161-70, 2011 Apr 14.
Artigo em Inglês | MEDLINE | ID: mdl-21325596

RESUMO

Fanconi anemia (FA) is a genetic condition associated with bone marrow (BM) failure, myelodysplasia (MDS), and acute myeloid leukemia (AML). We studied 57 FA patients with hypoplastic or aplastic anemia (n = 20), MDS (n = 18), AML (n = 11), or no BM abnormality (n = 8). BM samples were analyzed by karyotype, high-density DNA arrays with respect to paired fibroblasts, and by selected oncogene sequencing. A specific pattern of chromosomal abnormalities was found in MDS/AML, which included 1q+ (44.8%), 3q+ (41.4%), -7/7q (17.2%), and 11q- (13.8%). Moreover, cryptic RUNX1/AML1 lesions (translocations, deletions, or mutations) were observed for the first time in FA (20.7%). Rare mutations of NRAS, FLT3-ITD, MLL-PTD, ERG amplification, and ZFP36L2-PRDM16 translocation, but no TP53, TET2, CBL, NPM1, and CEBPα mutations were found. Frequent homozygosity regions were related not to somatic copy-neutral loss of heterozygosity but to consanguinity, suggesting that homologous recombination is not a common progression mechanism in FA. Importantly, the RUNX1 and other chromosomal/genomic lesions were found at the MDS/AML stages, except for 1q+, which was found at all stages. These data have implications for staging and therapeutic managing in FA patients, and also to analyze the mechanisms of clonal evolution and oncogenesis in a background of genomic instability and BM failure.


Assuntos
Subunidade alfa 2 de Fator de Ligação ao Core/genética , Anemia de Fanconi/genética , Instabilidade Genômica/genética , Leucemia Mieloide Aguda/genética , Síndromes Mielodisplásicas/genética , Adolescente , Adulto , Medula Óssea/fisiologia , Criança , Pré-Escolar , Anemia de Fanconi/complicações , Feminino , Dosagem de Genes/genética , Perfilação da Expressão Gênica , Regulação Leucêmica da Expressão Gênica , Genes Supressores de Tumor , Homozigoto , Humanos , Leucemia Mieloide Aguda/etiologia , Masculino , Pessoa de Meia-Idade , Síndromes Mielodisplásicas/etiologia , Polimorfismo de Nucleotídeo Único , Adulto Jovem
17.
Nat Genet ; 42(6): 530-5, 2010 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-20473312

RESUMO

PTPN2 (protein tyrosine phosphatase non-receptor type 2, also known as TC-PTP) is a cytosolic tyrosine phosphatase that functions as a negative regulator of a variety of tyrosine kinases and other signaling proteins. In agreement with its role in the regulation of the immune system, PTPN2 was identified as a susceptibility locus for autoimmune diseases. In this work, we describe the identification of focal deletions of PTPN2 in human T-cell acute lymphoblastic leukemia (T-ALL). Deletion of PTPN2 was specifically found in T-ALLs with aberrant expression of the TLX1 transcription factor oncogene, including four cases also expressing the NUP214-ABL1 tyrosine kinase. Knockdown of PTPN2 increased the proliferation and cytokine sensitivity of T-ALL cells. In addition, PTPN2 was identified as a negative regulator of NUP214-ABL1 kinase activity. Our study provides genetic and functional evidence for a tumor suppressor role of PTPN2 and suggests that expression of PTPN2 may modulate response to treatment.


Assuntos
Deleção de Genes , Leucemia-Linfoma Linfoblástico de Células T Precursoras/genética , Proteína Tirosina Fosfatase não Receptora Tipo 2/genética , Animais , Benzamidas , Linhagem Celular , Linhagem Celular Tumoral , Quimiocina CCL1/metabolismo , Técnicas de Silenciamento de Genes , Proteínas de Homeodomínio/genética , Humanos , Mesilato de Imatinib , Interleucina-2/metabolismo , Interleucina-7/metabolismo , Leucemia Experimental/genética , Camundongos , Piperazinas/uso terapêutico , Proteínas Proto-Oncogênicas/genética , Pirimidinas/uso terapêutico
18.
Leuk Res ; 34(4): 426-9, 2010 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-19796813

RESUMO

The Ikaros (Ikzf1) gene, encoding a transcription regulator, is a major tumor suppressor in B-cell acute lymphoblastic leukemia (B-ALL). In the mouse, however, loss of Ikaros is primarily associated with T-ALL development. Whether Ikaros is also implicated in human T-ALL remains unclear. We studied Ikaros in 25 human T-ALL samples from diverse molecular subtypes at the mRNA, protein, sequence and genomic copy number level. We found that Ikaros was abnormal in only one sample: one allele was lost by genomic deletion, while proteins generated from the remaining allele were delocalized and concentrated at a single cytoplasmic structure. Thus, inactivation of Ikaros by deletion or mutation is rare in human T-ALL.


Assuntos
Inativação Gênica , Fator de Transcrição Ikaros/genética , Leucemia-Linfoma Linfoblástico de Células T Precursoras/genética , Adolescente , Adulto , Criança , Pré-Escolar , Estudos de Coortes , Hibridização Genômica Comparativa , Deleção de Genes , Regulação Leucêmica da Expressão Gênica , Inativação Gênica/fisiologia , Humanos , Fator de Transcrição Ikaros/fisiologia , Lactente , Células Jurkat , Pessoa de Meia-Idade , Mutação/fisiologia , Isoformas de Proteínas/genética , Adulto Jovem
20.
Haematologica ; 93(11): 1658-65, 2008 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-18835836

RESUMO

BACKGROUND: The prognostic value of the ectopic activation of TLX3 gene expression, a major oncogenetic event associated with pediatric T-cell acute lymphoblastic leukemia, is controversial. Likewise, the frequency and the prognostic significance in pediatric T-cell acute lymphoblastic leukemia of the newly characterized NUP214-ABL1 fusion transcript is not yet clear. DESIGN AND METHODS: Two hundred children with T-cell acute lymphoblastic leukemia were treated in the French FRALLE-93 study from 1993 to 1999. The expression of TLX3, TLX1 and SILTAL1 genes was analyzed in samples from 92 patients by real-time quantitative reverse transcriptase polymerase chain reaction. Most of these samples were further studied for NUP214-ABL1 and CALM-AF10 fusion transcripts. RESULTS: The median follow-up was 7.9 years. At 5 years the overall survival (+/- standard deviation, %) was 62 (+/-3%) and leukemia-free survival was 58 (+/-3%). Patients with T-cell acute lymphoblastic leukemia positive for TLX3 had a poorer survival compared to those with T-ALL negative for TLX3 (overall survival: 45+/-11% vs. 57+/-5%, p=0.049). In multivariate analysis, TLX3 expression was an independent adverse risk factor predicting relapse with a hazard ratio of 2.44 (p=0.017) and an overall survival with a hazard ratio of 3.7 (p=0.001). NUP214-ABL1 was expressed in 16.6% of patients with TLX3-positive T-ALL (3 of 18); all of the patients with this association died before completion of the treatment. SILTAL expression did not significantly affect the prognosis of patients with T-cell acute lymphoblastic leukemia. Only three of 92 patients expressed the TLX1 gene and all three are alive. CONCLUSIONS: TLX3 gene expression is an independent risk factor predicting poor survival in childhood T-cell acute lymphoblastic leukemia. When co-expressed with TLX3, NUP214-ABL1 transcripts may increase the risk of poor survival.


Assuntos
Regulação Neoplásica da Expressão Gênica , Genótipo , Proteínas de Homeodomínio/genética , Leucemia-Linfoma de Células T do Adulto/genética , Leucemia-Linfoma Linfoblástico de Células Precursoras/genética , Adolescente , Adulto , Criança , Pré-Escolar , Feminino , Seguimentos , França , Humanos , Lactente , Leucemia-Linfoma de Células T do Adulto/mortalidade , Masculino , Leucemia-Linfoma Linfoblástico de Células Precursoras/mortalidade , Prognóstico , Taxa de Sobrevida , Fatores de Tempo , Transcrição Genética
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