Your browser doesn't support javascript.
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 22
Filtrar
Mais filtros










Base de dados
Intervalo de ano de publicação
1.
Nature ; 562(7727): 373-379, 2018 10.
Artigo em Inglês | MEDLINE | ID: mdl-30209392

RESUMO

Mixed phenotype acute leukaemia (MPAL) is a high-risk subtype of leukaemia with myeloid and lymphoid features, limited genetic characterization, and a lack of consensus regarding appropriate therapy. Here we show that the two principal subtypes of MPAL, T/myeloid (T/M) and B/myeloid (B/M), are genetically distinct. Rearrangement of ZNF384 is common in B/M MPAL, and biallelic WT1 alterations are common in T/M MPAL, which shares genomic features with early T-cell precursor acute lymphoblastic leukaemia. We show that the intratumoral immunophenotypic heterogeneity characteristic of MPAL is independent of somatic genetic variation, that founding lesions arise in primitive haematopoietic progenitors, and that individual phenotypic subpopulations can reconstitute the immunophenotypic diversity in vivo. These findings indicate that the cell of origin and founding lesions, rather than an accumulation of distinct genomic alterations, prime tumour cells for lineage promiscuity. Moreover, these findings position MPAL in the spectrum of immature leukaemias and provide a genetically informed framework for future clinical trials of potential treatments for MPAL.


Assuntos
Leucemia Aguda Bifenotípica/genética , Leucemia Aguda Bifenotípica/patologia , Linhagem da Célula/genética , Análise Mutacional de DNA , Feminino , Variação Genética/genética , Genoma Humano/genética , Genômica , Humanos , Imunofenotipagem , Leucemia Aguda Bifenotípica/classificação , Masculino , Modelos Genéticos , Mutação/genética , Células-Tronco Neoplásicas/imunologia , Células-Tronco Neoplásicas/metabolismo , Células-Tronco Neoplásicas/patologia , Fenótipo , Transativadores/genética
2.
Cancer Cell ; 33(5): 937-948.e8, 2018 05 14.
Artigo em Inglês | MEDLINE | ID: mdl-29681510

RESUMO

Somatic genetic alterations of IKZF1, which encodes the lymphoid transcription factor IKAROS, are common in high-risk B-progenitor acute lymphoblastic leukemia (ALL) and are associated with poor prognosis. Such alterations result in the acquisition of stem cell-like features, overexpression of adhesion molecules causing aberrant cell-cell and cell-stroma interaction, and decreased sensitivity to tyrosine kinase inhibitors. Here we report coding germline IKZF1 variation in familial childhood ALL and 0.9% of presumed sporadic B-ALL, identifying 28 unique variants in 45 children. The majority of variants adversely affected IKZF1 function and drug responsiveness of leukemic cells. These results identify IKZF1 as a leukemia predisposition gene, and emphasize the importance of germline genetic variation in the development of both familial and sporadic ALL.


Assuntos
Mutação em Linhagem Germinativa , Fator de Transcrição Ikaros/genética , Fator de Transcrição Ikaros/metabolismo , Leucemia-Linfoma Linfoblástico de Células Precursoras B/genética , Animais , Criança , Feminino , Mutação da Fase de Leitura , Predisposição Genética para Doença , Humanos , Masculino , Camundongos , Transplante de Neoplasias , Linhagem , Leucemia-Linfoma Linfoblástico de Células Precursoras B/metabolismo , Análise de Sequência de DNA
3.
Pediatr Int ; 59(3): 371-374, 2017 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-28317309

RESUMO

Infantile fibrosarcoma is a non-rhabdomyosarcoma soft-tissue sarcoma that occurs in infancy and which has a relatively good prognosis. A vincristine and dactinomycin (VA) regimen has been shown to be effective, although the duration of chemotherapy has not been well defined. We describe the case of a 4-month-old boy with a mass at the left dorsum of the foot who was diagnosed with infantile fibrosarcoma after resection of the tumor, the margin of which was macroscopically positive. VA treatment was carried out with careful monitoring of response and adverse effects. Pancytopenia was seen during the second cycle, and therapy was reduced thereafter. The treatment was continued for 38 weeks (12 cycles). There was no functional impairment, and no evidence of recurrence at 18 months after therapy.


Assuntos
Antineoplásicos/uso terapêutico , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Dactinomicina/uso terapêutico , Fibrossarcoma/tratamento farmacológico , Pé/cirurgia , Neoplasias de Tecidos Moles/tratamento farmacológico , Vincristina/uso terapêutico , Quimioterapia Adjuvante , Fibrossarcoma/cirurgia , Humanos , Lactente , Masculino , Neoplasias de Tecidos Moles/cirurgia
4.
Oncoimmunology ; 7(1): e1377872, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-29296538

RESUMO

The carcinoembryonic antigen glypican-3 (GPC3) is a good target of anticancer immunotherapy against pediatric solid tumors expressing GPC3. In this non-randomized, open-label, phase I clinical trial, we analyzed the safety and efficacy of GPC3-peptide vaccination in patients with pediatric solid tumors. Eighteen patients with pediatric solid tumors expressing GPC3 underwent GPC3-peptide vaccination (intradermal injections every 2 weeks), with the primary endpoint being the safety of GPC3-peptide vaccination and the secondary endpoints being immune response, as measured by interferon (IFN)-γ enzyme-linked immunospot assay and Dextramer staining, and the clinical outcomes of tumor response, progression free survival (PFS), and overall survival (OS). Our findings indicated that GPC3 vaccination was well tolerated. We observed disease-control rates [complete response (CR)+partial response+stable disease] of 66.7% after 2 months, and although patients in the progression group unable to induce GPC3-peptide-specific cytotoxic T lymphocytes (CTLs) received poor prognoses, patients in the partial-remission and remission groups or those with hepatoblastoma received good prognoses. The GPC3-peptide vaccine induced a GPC3-specific CTL response in seven patients, with PFS and OS significantly longer in patients with high GPC3-specific CTL frequencies than in those with low frequencies. Furthermore, we established GPC3-peptide-specific CTL clones from a resected-recurrent tumor from one patient, with these cells exhibiting GPC3-peptide-specific cytokine secretion. The results of this trial demonstrated that the GPC3-peptide-specific CTLs induced by the GPC3-peptide vaccine infiltrated tumor tissue, and use of the GPC3-peptide vaccine might prevent the recurrence of pediatric solid tumors, especially hepatoblastomas, after a second CR.

5.
J Pediatr Hematol Oncol ; 39(3): e167-e172, 2017 04.
Artigo em Inglês | MEDLINE | ID: mdl-28002256

RESUMO

Hospital-acquired Clostridium difficile infection (CDI) may cause life-threatening colitis for children with cancer, making identification of risk factors important. We described characteristics of pediatric cancer patients with primary and recurring CDI, and evaluated potential risk factors. Among 189 cancer patients, 51 cases (27%) of CDI and 94 matched controls of cancer patients without CDI were analyzed. Multivariable logistic regression was used to evaluate the association between CDI and several potential risk factors. Median age of CDI cases was lower (3.3 y; 0.60 to 16.2) than controls (7.7 y; 0.4 to 20.5). Median duration of neutropenia before CDI was longer for CDI cases (10.0 d; 0.0 to 30.0) compared with duration calculated from reference date in controls (6.0 d; 0.0 to 29.0). Multivariable analysis showed that older age was associated with reduced risk (≥7 vs. 0 to 3 y, odds ratio=0.11; 95% confidence interval, 0.02-0.54), and prolonged neutropenia was associated with increased risk (odds ratio=1.11; 95% confidence interval, 1.01-1.22). CDI recurred in 26% of cases. Younger age and prolonged neutropenia were risk factors for CDI in children with cancer. Increasing awareness to these risk factors will help to identify opportunities for CDI prevention in cancer patients.


Assuntos
Infecções por Clostridium/etiologia , Neoplasias/complicações , Adolescente , Fatores Etários , Estudos de Casos e Controles , Criança , Pré-Escolar , Infecções por Clostridium/virologia , Clostridium difficile , Humanos , Doença Iatrogênica , Lactente , Neutropenia/complicações , Fatores de Risco , Adulto Jovem
6.
Pediatr Int ; 59(2): 223-226, 2017 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-28026886

RESUMO

We describe the case of a 13-year-old girl with multifocal disseminated Ewing sarcoma family of tumor (ESFT) who received a 5/8 human leukocyte antigen-matched haploidentical hematopoietic cell transplantation to generate a graft-versus-tumor effect. The patient had grade 2 acute graft-versus-host disease (GVHD) of the skin and chronic GVHD nausea and abdominal pain that required prednisolone for 17 months, but has been free from ESFT for 3 years 10 months after therapy. The present case suggests a beneficial effect of haploidentical hematopoietic cell transplantation in disseminated ESFT.


Assuntos
Neoplasias Ósseas/terapia , Transplante de Células-Tronco Hematopoéticas/métodos , Ossos Pélvicos , Sarcoma de Ewing/terapia , Adolescente , Feminino , Doença Enxerto-Hospedeiro , Humanos
7.
Nat Genet ; 48(12): 1481-1489, 2016 12.
Artigo em Inglês | MEDLINE | ID: mdl-27776115

RESUMO

Chromosomal rearrangements deregulating hematopoietic transcription factors are common in acute lymphoblastic leukemia (ALL). Here we show that deregulation of the homeobox transcription factor gene DUX4 and the ETS transcription factor gene ERG is a hallmark of a subtype of B-progenitor ALL that comprises up to 7% of B-ALL. DUX4 rearrangement and overexpression was present in all cases and was accompanied by transcriptional deregulation of ERG, expression of a novel ERG isoform, ERGalt, and frequent ERG deletion. ERGalt uses a non-canonical first exon whose transcription was initiated by DUX4 binding. ERGalt retains the DNA-binding and transactivation domains of ERG, but it inhibits wild-type ERG transcriptional activity and is transforming. These results illustrate a unique paradigm of transcription factor deregulation in leukemia in which DUX4 deregulation results in loss of function of ERG, either by deletion or induced expression of an isoform that is a dominant-negative inhibitor of wild-type ERG function.


Assuntos
Transformação Celular Neoplásica/genética , Deleção de Genes , Regulação Neoplásica da Expressão Gênica , Rearranjo Gênico , Proteínas de Homeodomínio/genética , Leucemia-Linfoma Linfoblástico de Células Precursoras/genética , Adolescente , Adulto , Transformação Celular Neoplásica/patologia , Perfilação da Expressão Gênica , Humanos , Leucemia-Linfoma Linfoblástico de Células Precursoras/patologia , Isoformas de Proteínas , Regulador Transcricional ERG/genética , Adulto Jovem
8.
Rinsho Ketsueki ; 57(6): 748-53, 2016 06.
Artigo em Japonês | MEDLINE | ID: mdl-27384855

RESUMO

Thiopurine S-methyltransferase (TPMT) and nucleoside diphosphate-linked moiety X-type motif 15 (NUDT15) variants are considered to be genes responsible for severe myelotoxicity induced by 6-mercaptopurine (6MP). We report a 4-year-old girl with acute lymphoblastic leukemia, who developed the complication of severe 6MP-induced myelotoxicity due to homozygous NUDT15 variant alleles. In early consolidation therapy containing 6MP, her course was complicated by severe neutropenia (Grade 4) and chemotherapy had to be discontinued for 33 days. The 6MP dose was subsequently adjusted based on the white blood cell count. The ratios of the prescribed 6MP dose over the protocol dose in early consolidation, central nervous system (CNS) prophylaxis, re-induction, interim maintenance and maintenance therapy were 63%, 27%, 4%, 26% and 7%, respectively. Suspension of therapy was required during early consolidation, CNS prophylaxis and interim maintenance therapy. We investigated candidate genes for 6MP-associated myelotoxicity and found homozygous NUDT15 variant alleles and a heterozygous inosine triphosphate pyrophosphatase (ITPA) variant allele. In patients with homozygous NUDT15 variants, drastic reduction (less than 10%) of the 6MP dose from the protocol dose might be required not only during maintenance therapy, but also during other treatment courses containing 6MP. Screening of candidate genes at diagnosis is recommended in order to avoid serious adverse events.


Assuntos
Mercaptopurina/efeitos adversos , Mutação de Sentido Incorreto , Neutropenia/induzido quimicamente , Leucemia-Linfoma Linfoblástico de Células Precursoras/tratamento farmacológico , Pirofosfatases/genética , Pré-Escolar , Feminino , Homozigoto , Humanos , Leucemia-Linfoma Linfoblástico de Células Precursoras/genética
9.
Pediatr Int ; 58(8): 766-9, 2016 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-27324740

RESUMO

Ewing sarcoma/primitive neuroectodermal tumor (ES/PNET) of the kidney is extremely rare, and is usually diagnosed after nephrectomy without neoadjuvant chemotherapy. Although ifosfamide and etoposide improve survival to a great extent in ES/PNET, the use of nephrotoxic agent, particularly ifosfamide, is a concern after nephrectomy. We describe the case of a 14-year-old female patient with abdominal mass who was diagnosed with ES/PNET of the right kidney after nephrectomy. Adjuvant chemotherapy including ifosfamide and etoposide were given. The estimated glomerular filtration rate decreased to 75% after the end of therapy. There was no evidence of recurrence 70 months after initial diagnosis.


Assuntos
Ifosfamida/uso terapêutico , Neoplasias Renais/tratamento farmacológico , Sarcoma de Ewing/tratamento farmacológico , Adolescente , Antineoplásicos Alquilantes/uso terapêutico , Feminino , Humanos , Neoplasias Renais/diagnóstico , Imagem por Ressonância Magnética , Tumores Neuroectodérmicos Primitivos , Sarcoma de Ewing/diagnóstico , Tomografia Computadorizada por Raios X
10.
J Proteome Res ; 13(2): 915-24, 2014 Feb 07.
Artigo em Inglês | MEDLINE | ID: mdl-24328109

RESUMO

Formalin-fixed and paraffin-embedded (FFPE) sections mounted on microscope slides are one of the largest available resources for retrospective research on various diseases, but quantitative phosphoproteome analysis of FFPE sections has never been achieved because of the extreme difficulty of procuring sufficient phosphopeptides from the limited amounts of proteins on the slides. Here, we present the first protocol for quantitative phosphoproteome analysis of FFPE sections by utilizing phase-transfer surfactant-aided extraction/tryptic digestion of FFPE proteins followed by high-recovery phosphopeptide enrichment via lactic acid-modified titania chromatography. We established that FFPE sections retain a similar phosphoproteome to fresh tissue specimens during storage for at least 9 months, confirming the utility of our method for evaluating phosphorylation profiles in various diseases. We also verified that chemical labeling based on reductive dimethylation of amino groups was feasible for quantitative phosphoproteome analysis of FFPE samples on slides. Furthermore, we improved the LC-MS sensitivity by miniaturizing nanoLC columns to 25 µm inner diameter. With this system, we could identify 1090 phosphopeptides from a single FFPE section obtained from a microscope slide, containing 25.2 ± 5.4 µg of proteins. This protocol should be useful for large-scale phosphoproteome analysis of archival FFPE slides, especially scarce samples from patients with rare diseases.


Assuntos
Formaldeído/química , Inclusão em Parafina , Fosfoproteínas/metabolismo , Proteoma , Fixação de Tecidos , Animais , Cromatografia Líquida , Camundongos , Camundongos Endogâmicos C57BL , Espectrometria de Massas em Tandem
11.
Nat Commun ; 4: 1639, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-23535660

RESUMO

The vertebrate mineralized skeleton is known to have first emerged as an exoskeleton that extensively covered the fossil jawless fish. The evolutionary origin of this exoskeleton has long been attributed to the emergence of the neural crest, but experimental evaluation for this is still poor. Here we determine the embryonic origin of scales and fin rays of medaka (teleost trunk exoskeletons) by applying long-term cell labelling methods, and demonstrate that both tissues are mesodermal in origin. Neural crest cells, however, fail to contribute to these tissues. This result suggests that the trunk neural crest has no skeletogenic capability in fish, instead highlighting the dominant role of the mesoderm in the evolution of the trunk skeleton. This further implies that the role of the neural crest in skeletogenesis has been predominant in the cephalic region from the early stage of vertebrate evolution.


Assuntos
Mesoderma/anatomia & histologia , Oryzias/anatomia & histologia , Esqueleto , Animais
12.
Cell Stem Cell ; 9(3): 247-61, 2011 Sep 02.
Artigo em Inglês | MEDLINE | ID: mdl-21885020

RESUMO

Cell cycle regulators play critical roles in the balance between hematopoietic stem cell (HSC) dormancy and proliferation. In this study, we report that cell cycle entry proceeded normally in HSCs null for cyclin-dependent kinase (CDK) inhibitor p57 due to compensatory upregulation of p27. HSCs null for both p57 and p27, however, were more proliferative and had reduced capacity to engraft in transplantation. We found that heat shock cognate protein 70 (Hsc70) interacts with both p57 and p27 and that the subcellular localization of Hsc70 was critical to maintain HSC cell cycle kinetics. Combined deficiency of p57 and p27 in HSCs resulted in nuclear import of an Hsc70/cyclin D1 complex, concomitant with Rb phosphorylation, and elicited severe defects in maintaining HSC quiescence. Taken together, these data suggest that regulation of cytoplasmic localization of Hsc70/cyclin D1 complex by p57 and p27 is a key intracellular mechanism in controlling HSC dormancy.


Assuntos
Ciclina D1/metabolismo , Inibidor de Quinase Dependente de Ciclina p27/metabolismo , Inibidor de Quinase Dependente de Ciclina p57/metabolismo , Proteínas de Choque Térmico HSC70/metabolismo , Células-Tronco Hematopoéticas/metabolismo , Animais , Ciclo Celular/genética , Proliferação de Células , Células Cultivadas , Senescência Celular/genética , Ciclina D1/genética , Inibidor de Quinase Dependente de Ciclina p27/genética , Inibidor de Quinase Dependente de Ciclina p57/genética , Regulação da Expressão Gênica no Desenvolvimento/genética , Células-Tronco Hematopoéticas/patologia , Imuno-Histoquímica , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Ligação Proteica , Transporte Proteico
13.
Blood ; 116(9): 1422-32, 2010 Sep 02.
Artigo em Inglês | MEDLINE | ID: mdl-20472830

RESUMO

The endosteal niche is critical for the maintenance of hematopoietic stem cells (HSCs). However, it consists of a heterogeneous population in terms of differentiation stage and function. In this study, we characterized endosteal cell populations and examined their ability to maintain HSCs. Bone marrow endosteal cells were subdivided into immature mesenchymal cell-enriched ALCAM(-)Sca-1(+) cells, osteoblast-enriched ALCAM(+)Sca-1(-), and ALCAM(-)Sca-1(-) cells. We found that all 3 fractions maintained long-term reconstitution (LTR) activity of HSCs in an in vitro culture. In particular, ALCAM(+)Sca-1(-) cells significantly enhanced the LTR activity of HSCs by the up-regulation of homing- and cell adhesion-related genes in HSCs. Microarray analysis showed that ALCAM(-)Sca-1(+) fraction highly expressed cytokine-related genes, whereas the ALCAM(+)Sca-1(-) fraction expressed multiple cell adhesion molecules, such as cadherins, at a greater level than the other fractions, indicating that the interaction between HSCs and osteoblasts via cell adhesion molecules enhanced the LTR activity of HSCs. Furthermore, we found an osteoblastic marker(low/-) subpopulation in ALCAM(+)Sca-1(-) fraction that expressed cytokines, such as Angpt1 and Thpo, and stem cell marker genes. Altogether, these data suggest that multiple subsets of osteoblasts and mesenchymal progenitor cells constitute the endosteal niche and regulate HSCs in adult bone marrow.


Assuntos
Células da Medula Óssea/metabolismo , Células-Tronco Hematopoéticas/citologia , Células-Tronco Mesenquimais/metabolismo , Osteoblastos/citologia , Osteoblastos/metabolismo , Molécula de Adesão de Leucócito Ativado/metabolismo , Animais , Antígenos de Diferenciação/metabolismo , Biomarcadores/metabolismo , Western Blotting , Osso e Ossos/citologia , Osso e Ossos/metabolismo , Diferenciação Celular , Ensaio de Unidades Formadoras de Colônias , Perfilação da Expressão Gênica , Técnicas Imunoenzimáticas , Camundongos , Camundongos Endogâmicos C57BL , Análise de Sequência com Séries de Oligonucleotídeos , RNA Mensageiro/genética , Reação em Cadeia da Polimerase Via Transcriptase Reversa
14.
Blood ; 116(4): 554-63, 2010 Jul 29.
Artigo em Inglês | MEDLINE | ID: mdl-20427705

RESUMO

During postnatal life, the bone marrow (BM) supports both self-renewal and differentiation of hematopoietic stem cells (HSCs) in specialized microenvironments termed stem cell niches. Cell-cell and cell-extracellular matrix interactions between HSCs and their niches are critical for the maintenance of HSC properties. Here, we analyzed the function of N-cadherin in the regulation of the proliferation and long-term repopulation activity of hematopoietic stem/progenitor cells (HSPCs) by the transduction of N-cadherin shRNA. Inhibition of N-cadherin expression accelerated cell division in vitro and reduced the lodgment of donor HSPCs to the endosteal surface, resulting in a significant reduction in long-term engraftment. Cotransduction of N-cadherin shRNA and a mutant N-cadherin that introduced the silent mutations to shRNA target sequences rescued the accelerated cell division and reconstitution phenotypes. In addition, the requirement of N-cadherin for HSPC engraftment appears to be niche specific, as shN-cad-transduced lineage(-)Sca-1(+)c-Kit(+) cells successfully engrafted in spleen, which lacks an osteoblastic niche. These findings suggest that N-cad-mediated cell adhesion is functionally required for the establishment of hematopoiesis in the BM niche after BM transplantation.


Assuntos
Caderinas/genética , Sobrevivência de Enxerto/genética , Transplante de Células-Tronco Hematopoéticas , Animais , Caderinas/fisiologia , Adesão Celular/genética , Adesão Celular/fisiologia , Movimento Celular/genética , Movimento Celular/fisiologia , Sobrevivência Celular/genética , Células Cultivadas , Técnicas de Silenciamento de Genes , Células-Tronco Hematopoéticas/fisiologia , Camundongos , Camundongos Congênicos , Camundongos Endogâmicos C57BL , Células NIH 3T3 , Nicho de Células-Tronco/fisiologia , Fatores de Tempo
16.
Exp Hematol ; 38(2): 82-9, 2010 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-19945502

RESUMO

OBJECTIVE: Angiopoietin-1 (Ang-1) plays a critical role in the maintenance of hematopoietic stem cells (HSCs) in the bone marrow (BM) through its binding to the Tie2 receptor. Ang-2, another Tie2 ligand, is known to be an antagonist of Tie2/Ang-1 signaling in angiogenesis; however, its function in regulation of HSCs remains unclear. Here, we investigated the functional differences between Ang-1 and Ang-2 in the maintenance of HSCs. MATERIALS AND METHODS: We treated mouse BM lineage(-)Sca-1(+)c-Kit(+) side population(+) cells with Ang-1 and/or Ang-2, and evaluated angiopoietin function by gene expression analysis, immunocytochemical staining of phosphorylated Akt, a colony-formation assay, and a long-term BM reconstitution assay. RESULTS: Gene expression analysis and BM transplantation assay revealed that Ang-1 upregulated expression of p57, p18, Itgb1, Alcam, Tie2, Hoxb4, and Bmi1 genes in HSCs, while Ang-2 antagonized the effects of Ang-1. Ang-1 enhanced the phosphorylation of Akt, while Ang-2 again reduced the effect of Ang-1. The colony assay demonstrated that neither Ang-1, nor Ang-2 influenced the colony formation of HSCs. BM transplantation assay, following in vitro cultivation of HSCs with angiopoietins, showed that Ang-1 maintained long-term repopulating activity of HSCs, while the addition of Ang-2 interfered drastically with the effects of Ang-1. CONCLUSION: Gene expression analysis and BM transplantation assay demonstrated that Ang-1 maintained HSC activity in an in vitro culture. In contrast, Ang-2 reversed the effects of Ang-1/Tie2 signaling in the regulation of long-term HSCs. Our data suggest that Ang-1 is a dominant ligand for the Tie2 receptor in long HSCs in BM.


Assuntos
Angiopoietina-1/fisiologia , Angiopoietina-2/fisiologia , Células-Tronco Hematopoéticas/fisiologia , Receptor TIE-2/metabolismo , Angiopoietina-1/antagonistas & inibidores , Angiopoietina-1/farmacologia , Angiopoietina-2/farmacologia , Animais , Células da Medula Óssea/citologia , Células da Medula Óssea/metabolismo , Transplante de Medula Óssea , Adesão Celular/genética , Divisão Celular/efeitos dos fármacos , Células Cultivadas , Ensaio de Unidades Formadoras de Colônias , Regulação da Expressão Gênica/efeitos dos fármacos , Células-Tronco Hematopoéticas/citologia , Camundongos , Camundongos Endogâmicos BALB C , Fosforilação/efeitos dos fármacos , Proteínas Proto-Oncogênicas c-akt/metabolismo
17.
Ann N Y Acad Sci ; 1176: 36-46, 2009 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-19796231

RESUMO

During postnatal life, the bone marrow (BM) supports both the self-renewal and differentiation of hematopoietic stem cells (HSCs) in specialized niches. The interaction of HSCs with their niches also regulates the quiescence of HSCs. HSC quiescence is critical to ensure lifelong hematopoiesis and to protect the HSC pool from myelotoxic insult and premature exhaustion under conditions of hematopoietic stress. Here we identified long-term (LT)-HSCs expressing the thrombopoietin (THPO) receptor, Mpl, as a quiescent population in adult BM. THPO was produced by bone-lining cells in the endosteum. Inhibition and stimulation of the THPO/Mpl pathway produced opposite effects on the quiescence of LT-HSC. Exogenous THPO transiently increased the quiescent LT-HSC population, such as side-population and pyronin Y-negative cells. In contrast, administration of an anti-Mpl neutralizing antibody, AMM2, suppressed the quiescence of LT-HSCs and enabled HSC engraftment without irradiation, indicating that inhibition of THPO/Mpl signaling reduces HSC-niche interactions. Moreover, it suggests that inhibiting the HSC-niche interaction could represent a novel technique for bone marrow transplantation without irradiation. Altogether, these data suggest that the THPO/Mpl signaling pathway is a novel niche component in the endosteum, and in the steady-state condition, this signaling pathway plays a critical role in the regulation of LT-HSCs in the osteoblastic niche.


Assuntos
Células-Tronco Hematopoéticas/fisiologia , Receptores de Trombopoetina/fisiologia , Nicho de Células-Tronco/fisiologia , Animais , Transplante de Medula Óssea , Humanos , Camundongos , Receptores de Trombopoetina/antagonistas & inibidores , Transdução de Sinais
18.
Nat Med ; 15(6): 696-700, 2009 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-19483695

RESUMO

Type I interferons (IFNs), a family of cytokines, orchestrate numerous biological and cellular processes1, 2, 3. Although it is well known that type I IFNs are essential for establishing the host antiviral state4, their role in hematopoietic homeostasis has not been studied. Here we show that type I IFNs induce proliferation and exhaustion in hematopoietic stem cells (HSCs) and that interferon regulatory factor-2 (IRF2), a transcriptional suppressor of type I IFN signaling5, 6, preserves the self-renewal and multilineage differentiation capacity of HSCs. HSCs were substantially less abundant in the bone marrow of Irf2-/- as compared to Irf2+/- mice. Irf2-/- HSCs showed enhanced cell cycling status and failed to produce hematopoietic cells in competitive repopulation assays, and the reconstituting capacity of Irf2-/- HSCs was restored by disabling type I IFN signaling in these cells. In wild-type mice, injection of poly(I:C), an inducer of type I IFN signaling, or IFN- induced HSC proliferation, and chronic type I IFN signaling further reduced the number of quiescent HSCs. Notably, combined poly(I:C) and 5-fluorouracil (5-FU) treatment allowed exogenous HSC engraftment and hematopoietic reconstitution in WT mice. Our findings provide insight into the molecular basis for the maintenance of HSC quiescence and may lead to improvements in bone marrow transplantation and type I IFN-based therapies for viral infection and cancer.


Assuntos
Células-Tronco Hematopoéticas/efeitos dos fármacos , Células-Tronco Hematopoéticas/metabolismo , Fator Regulador 2 de Interferon/metabolismo , Interferon Tipo I/farmacologia , Animais , Proliferação de Células , Células-Tronco Hematopoéticas/citologia , Fator Regulador 2 de Interferon/deficiência , Fator Regulador 2 de Interferon/genética , Camundongos , Camundongos Knockout
19.
Biochem Biophys Res Commun ; 378(3): 467-72, 2009 Jan 16.
Artigo em Inglês | MEDLINE | ID: mdl-19032938

RESUMO

Hematopoietic stem cells (HSCs) reside in hypoxic areas of the bone marrow. However, the role of hypoxia in the maintenance of HSCs has not been fully characterized. We performed xenotransplantation of human cord blood cells cultured in hypoxic or normoxic conditions into adult NOD/SCID/IL-2Rgamma(null) (NOG) mice. Hypoxic culture (1% O(2)) for 6 days efficiently supported the maintenance of HSCs, although cell proliferation was suppressed compared to the normoxic culture. In contrast, hypoxia did not affect in vitro colony-forming ability. Upregulation of a cell cycle inhibitor, p21, was observed in hypoxic culture. Immunohistochemical analysis of recipient bone marrow revealed that engrafted CD34(+)CD38(-) cord blood HSCs were hypoxic. Taken together, these results demonstrate the significance of hypoxia in the maintenance of quiescent human cord blood HSCs.


Assuntos
Diferenciação Celular , Sangue Fetal/citologia , Células-Tronco Hematopoéticas/fisiologia , Anaerobiose , Animais , Antígenos CD34/metabolismo , Técnicas de Cultura de Células , Células Cultivadas , Inibidor de Quinase Dependente de Ciclina p21/metabolismo , Sangue Fetal/fisiologia , Células-Tronco Hematopoéticas/citologia , Humanos , Camundongos , Camundongos Mutantes , Transplante Heterólogo , Regulação para Cima
20.
Biochem Biophys Res Commun ; 363(3): 578-83, 2007 Nov 23.
Artigo em Inglês | MEDLINE | ID: mdl-17897629

RESUMO

During postnatal life, the bone marrow (BM) supports both self-renewal and differentiation of hematopoietic stem cells (HSCs) in specialized niches, such as osteoblastic niche and vascular niche. A cell adhesion molecule, N-cadherin expressed in the HSCs and osteoblasts, suggesting that homophylic binding of N-cadherin induce the adhesion of HSCs to the niche cells. Here we demonstrate that an anti-cancer drug, 5-fuluorouracil induces reactive oxygen species (ROS) in HSCs, which suppressed N-cadherin expression. These events result in the shift of side population (SP) cells to non-SP cells, indicating that quiescent HSCs are detached from the niche. Administration of a potent anti-oxidant, N-acetyl cystein (NAC) suppressed the shift from SP cells. These data suggest that ROS suppressed the N-cadherin-mediated cell adhesion, and induce the exit of HSCs from the niche.


Assuntos
Células-Tronco Hematopoéticas/metabolismo , Estresse Oxidativo/fisiologia , Acetilcisteína/farmacologia , Animais , Células da Medula Óssea/citologia , Células da Medula Óssea/efeitos dos fármacos , Células da Medula Óssea/metabolismo , Caderinas/genética , Caderinas/metabolismo , Contagem de Células , Células Cultivadas , Inibidores Enzimáticos/farmacologia , Citometria de Fluxo , Fluoruracila/farmacologia , Depuradores de Radicais Livres/farmacologia , Expressão Gênica/efeitos dos fármacos , Células-Tronco Hematopoéticas/citologia , Células-Tronco Hematopoéticas/efeitos dos fármacos , Imidazóis/farmacologia , Imuno-Histoquímica , Camundongos , Camundongos Endogâmicos C57BL , Piridinas/farmacologia , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Espécies Reativas de Oxigênio/metabolismo , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Fatores de Tempo , Proteínas Quinases p38 Ativadas por Mitógeno/antagonistas & inibidores , Proteínas Quinases p38 Ativadas por Mitógeno/genética , Proteínas Quinases p38 Ativadas por Mitógeno/metabolismo
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA