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1.
Arthritis Rheumatol ; 76(6): 869-881, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38272827

RESUMO

OBJECTIVE: In this study, we examine how advancements in novel antirheumatic drugs affect the clinicopathologic features of lymphoproliferative disorder (LPD) in patients with rheumatoid arthritis (RA). METHODS: In this multicenter study across 53 hospitals in Japan, we characterized patients with RA who developed LPDs and visited the hospitals between January 1999 and March 2021. The statistical tools used included Fisher's exact test, the Mann-Whitney U-test, the log-rank test, logistic regression analysis, and Cox proportional hazards models. RESULTS: Overall, 752 patients with RA-associated LPD (RA-LPD) and 770 with sporadic LPD were included in the study. We observed significant differences in the clinicopathologic features between patients with RA-LPD and those with sporadic LPD. Histopathological analysis revealed a high frequency of LPD-associated immunosuppressive conditions. Furthermore, patients with RA-LPD were evaluated based on the antirheumatic drugs administered. The methotrexate (MTX) plus tacrolimus and MTX plus tumor necrosis factor inhibitor (TNFi) groups had different affected site frequencies and histologic subtypes than the MTX-only group. Moreover, MTX and TNFi may synergistically affect susceptibility to Epstein-Barr virus infection. In case of antirheumatic drugs administered after LPD onset, tocilizumab (TCZ)-only therapy was associated with lower frequency of regrowth after spontaneous regression than other regimens. CONCLUSION: Antirheumatic drugs administered before LPD onset may influence the clinicopathologic features of RA-LPD, with patterns changing over time. Furthermore, TCZ-only regimens are recommended after LPD onset.


Assuntos
Antirreumáticos , Artrite Reumatoide , Transtornos Linfoproliferativos , Metotrexato , Inibidores do Fator de Necrose Tumoral , Humanos , Artrite Reumatoide/tratamento farmacológico , Artrite Reumatoide/complicações , Antirreumáticos/uso terapêutico , Antirreumáticos/efeitos adversos , Transtornos Linfoproliferativos/induzido quimicamente , Masculino , Feminino , Pessoa de Meia-Idade , Metotrexato/uso terapêutico , Idoso , Inibidores do Fator de Necrose Tumoral/uso terapêutico , Inibidores do Fator de Necrose Tumoral/efeitos adversos , Japão , Tacrolimo/uso terapêutico , Tacrolimo/efeitos adversos , Quimioterapia Combinada , Infecções por Vírus Epstein-Barr/complicações , Adulto
2.
Leukemia ; 36(5): 1361-1370, 2022 05.
Artigo em Inglês | MEDLINE | ID: mdl-35347237

RESUMO

Fit patients with peripheral T-cell lymphoma, not otherwise specified (PTCL-NOS) and angioimmunoblastic T-cell lymphoma (AITL) in relapsed or refractory (R/R) disease status often receive salvage chemotherapy followed by autologous hematopoietic stem cell transplantation (autoHCT) or allogeneic HCT (alloHCT). However, there is no consensus on the type of HCT that should be applied for such patients. Herein, we retrospectively evaluated the survival outcome of 760 adult R/R PTCL-NOS or AITL patients who underwent the first HCT. Among them, 318 relapsed after first remission (REL) and 442 were refractory to the primary therapy (PIF). The 4-year overall survival (OS) of autoHCT and alloHCT was 50 and 50% for REL patients, and 52 and 49% for PIF patients, respectively. In the multivariable analysis, alloHCT tended to be associated with better progression-free survival (PFS) in REL (hazard ratio [HR] 0.74; 95% confidence interval [CI]: 0.53-1.03), and significantly better PFS in PIF (HR 0.64; 95% CI: 0.46-0.88) compared with autoHCT. The subgroup analysis with propensity-score matching showed that alloHCT was associated with better OS for REL-sensitive and PIF-nonremission disease. This study suggested that the advantage of alloHCT for R/R PTCL-NOS or AITL is different, depending on the disease status at HCT.


Assuntos
Transplante de Células-Tronco Hematopoéticas , Linfadenopatia Imunoblástica , Linfoma de Células T Periférico , Adulto , Humanos , Linfoma de Células T Periférico/patologia , Estudos Retrospectivos , Transplante Autólogo
3.
Rinsho Ketsueki ; 62(10): 1488-1492, 2021.
Artigo em Japonês | MEDLINE | ID: mdl-34732621

RESUMO

COVID-19 is a viral infection characterized by a cytokine storm similar to that in acute respiratory distress syndrome (ARDS). Neutrophils and monocytes are known to play an important role in tissue damage in ARDS. COVID-19 has been reported to be more severe in patients with hematological malignancies; however, there are few reports of COVID-19 in patients with aplastic anemia. Moreover, how aplastic anemia affects COVID-19 remains unclear. Here, we report the case of a COVID-19 patient with aplastic anemia who had high serum IL-6 levels but did not progress to the severe form of COVID-19. We inferred that severe neutropenia and monocytopenia due to aplastic anemia could contribute to a mild form of COVID-19, although a risk of more severe secondary bacterial infections exists.


Assuntos
Anemia Aplástica , COVID-19 , Síndrome da Liberação de Citocina , Humanos , Interleucina-6 , SARS-CoV-2
4.
Intern Med ; 60(23): 3785-3788, 2021 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-34053991

RESUMO

Congenital mutations of the Wilms' tumor 1 (WT1) gene can lead to various abnormalities, including renal/gonadal developmental disorders and cardiac malformations. Although there have been many reports of somatic WT1 mutations in patients with acute myeloid leukemia and myelodysplastic syndrome, congenital WT1 mutations have not been reported in hematological disorders. We herein report a patient with early-onset clonal cytopenia of undetermined significance that was associated with a congenital mutation of WT1 and an acquired mutation of DNMT3A [encoding DNA (cytosine-5)-methyltransferase 3A].


Assuntos
Hematopoiese Clonal , DNA Metiltransferase 3A/genética , Neoplasias Renais , Tumor de Wilms , Genes do Tumor de Wilms , Humanos , Mutação , Proteínas WT1/genética , Tumor de Wilms/genética
5.
Int J Hematol ; 114(2): 217-221, 2021 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-33847924

RESUMO

High pre-treatment serum soluble interleukin-2 receptor (sIL-2R) levels are associated with poor overall survival (OS) of patients with newly diagnosed follicular lymphoma (FL). We evaluated the usefulness of pre-treatment sIL-2R levels in selecting a treatment regimen for advanced-stage FL with low tumor burden (FL-LTB). This retrospective, multicenter observational study enrolled consecutive patients who received a rituximab-containing regimen for newly diagnosed advanced stage FL-LTB (grade 1-3a) between 2008 and 2018. We applied a previously reported cut-off value of 1800 IU/mL for sIL-2R. A total of 211 patients were eligible for the analysis. Among patients with high sIL-2R (47 patients, 22.3%), the OS rates for patients treated by rituximab monotherapy (R-mono) (11 patients) were significantly lower than those treated by rituximab-combination chemotherapy (R-chemo) (36 patients): 5-year OS rates were 66.7% and 94.4%, respectively (P = 0.007). Among patients with low sIL-2R (164 patients, 77.7%), OS rates were comparably good between the R-mono group (34 patients) and the R-chemo group (130 patients): 5-year OS rates were 100% and 98.3%, respectively (P = 0.38). Our results suggest that R-chemo may yield better OS than R-mono for patients with newly diagnosed advanced-stage FL-LTB and high pre-treatment serum sIL-2R levels.


Assuntos
Biomarcadores Tumorais , Linfoma Folicular/sangue , Linfoma Folicular/diagnóstico , Receptores de Interleucina-2/sangue , Adulto , Idoso , Idoso de 80 Anos ou mais , Protocolos de Quimioterapia Combinada Antineoplásica/efeitos adversos , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Tomada de Decisão Clínica , Gerenciamento Clínico , Feminino , Humanos , Linfoma Folicular/mortalidade , Linfoma Folicular/terapia , Masculino , Pessoa de Meia-Idade , Estadiamento de Neoplasias , Prognóstico , Carga Tumoral
6.
Ann Hematol ; 99(9): 2133-2139, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32533251

RESUMO

The overall outcome of patients with advanced-stage follicular lymphoma (FL) has improved significantly. However, some patients still develop multiple relapsed/refractory FL (RRFL). To address the still-limited data on this population, we performed this multi-center retrospective study. We analyzed 41 patients who received third-line treatment for RRFL at 8 institutes. The median age at diagnosis was 59 years (range, 38-70). The median progression-free survival (PFS) and probability of PFS at 2 years were 1.61 years and 39.4%, respectively, after third-line chemotherapy, and 0.45 years and 19.0%, respectively, after fourth-line chemotherapy. Objective response (OR) after third-line chemotherapy was achieved in 24 patients (53.7%). Bendamustine (Ben)-based regimens were associated with a significantly higher OR rate than other regimens (77.8% vs. 40.0%, respectively, P = 0.025). The median overall survival (OS) and probability of OS at 2 years were 4.71 years and 65.9%, respectively, after third-line chemotherapy, and 1.01 year and 45.1%, respectively, after fourth-line chemotherapy. In conclusion, this study had a small sample size and retrospective design, but it was able to demonstrate poor response rate and duration in patients with multiple RRFL, particularly after fourth-line chemotherapy. The optimal treatment strategy in this population should be clarified, including possibly hematopoietic stem cell transplantation.


Assuntos
Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Linfoma Folicular/diagnóstico , Linfoma Folicular/tratamento farmacológico , Recidiva Local de Neoplasia/diagnóstico , Recidiva Local de Neoplasia/tratamento farmacológico , Adulto , Idoso , Estudos de Coortes , Feminino , Seguimentos , Humanos , Linfoma Folicular/mortalidade , Masculino , Pessoa de Meia-Idade , Recidiva Local de Neoplasia/mortalidade , Estudos Retrospectivos , Taxa de Sobrevida/tendências
7.
Leuk Lymphoma ; 61(9): 2113-2121, 2020 09.
Artigo em Inglês | MEDLINE | ID: mdl-32366194

RESUMO

This retrospective, multicenter observational study investigated the prognostic value of pretreatment serum soluble interleukin-2 receptor (sIL-2R) level for outcomes of newly diagnosed follicular lymphoma (FL) grade 1-3a who required treatment at diagnosis. A total of 628 patients were recorded, and 502 of these were eligible for analysis. Patients were divided into four quartiles, based on their serum sIL-2R levels as follows: Q1 (sIL-2R < 520 IU/mL), Q2 (520 ≤ sIL-2R < 1030 IU/mL), Q3 (1030 ≤ sIL-2R < 2530 IU/mL) and Q4 (sIL-2R ≥ 2530 IU/mL). Using a multivariable Cox proportional-hazards model, we showed the adjusted probability of overall survival (OS) decreased with increasing serum sIL-2R levels (p for trend = .007). Similar trends were observed for disease-specific survival (DSS) and progression-free survival (PFS). In conclusion, pretreatment serum sIL-2R levels significantly and dose-dependently associate with worse outcomes (OS, DSS and PFS) of patients with newly diagnosed FL.


Assuntos
Linfoma Folicular , Humanos , Linfoma Folicular/diagnóstico , Linfoma Folicular/terapia , Prognóstico , Modelos de Riscos Proporcionais , Receptores de Interleucina-2 , Estudos Retrospectivos
8.
Biol Blood Marrow Transplant ; 25(1): e23-e27, 2019 01.
Artigo em Inglês | MEDLINE | ID: mdl-30103016

RESUMO

Acute panmyelosis with myelofibrosis (APMF) is a rare subtype of acute myeloid leukemia characterized by acute onset of cytopenias and bone marrow fibrosis in the absence of splenomegaly. Because the prognosis of APMF is extremely poor even after chemotherapy, hematopoietic cell transplantation (HCT) has been used to treat APMF. However, the outcome after HCT for APMF remains unclear. To evaluate the outcomes and prognostic factors after HCT as a therapeutic modality for APMF, we retrospectively analyzed the Japanese registration data of 40 APMF patients who received allogeneic and syngeneic HCT between 2005 and 2015. The median age at HCT was 53.5 years (range, 16 to 70). The disease status at HCT was first complete remission (CR1) in 13 patients (33%). The probability of overall survival and the cumulative incidence of relapse at 3 years were 24% and 59%, respectively. Univariate analysis identified that female sex and disease status CR1 at the time of HCT were significantly associated with higher overall survival. Although APMF patients have a poor long-term prognosis even after syngeneic and allogeneic HCT, these data suggested that allogeneic HCT offered a curative option for APMF.


Assuntos
Transplante de Células-Tronco Hematopoéticas , Leucemia Mieloide Aguda/mortalidade , Leucemia Mieloide Aguda/terapia , Sistema de Registros , Adolescente , Adulto , Idoso , Aloenxertos , Intervalo Livre de Doença , Feminino , Humanos , Japão , Leucemia Mieloide Aguda/classificação , Masculino , Pessoa de Meia-Idade , Estudos Retrospectivos , Taxa de Sobrevida
9.
Asian J Endosc Surg ; 12(3): 315-317, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-30259706

RESUMO

Stricture of the celiac artery caused by the median arcuate ligament induces abdominal ischemic symptoms and aneurysm near the pancreatic head. However, the need to treat asymptomatic patients is unclear. We safely performed surgical decompression of a stricture of the celiac artery by MAL in an asymptomatic patient at the same time as gastrectomy for gastric cancer. After surgery, the stricture of the celiac artery had disappeared as demonstrated by CT scan and 3-D CT angiography.


Assuntos
Descompressão Cirúrgica , Gastrectomia , Laparoscopia , Síndrome do Ligamento Arqueado Mediano/cirurgia , Neoplasias Gástricas/complicações , Feminino , Humanos , Síndrome do Ligamento Arqueado Mediano/diagnóstico , Síndrome do Ligamento Arqueado Mediano/etiologia , Pessoa de Meia-Idade , Neoplasias Gástricas/diagnóstico , Neoplasias Gástricas/cirurgia
10.
Hinyokika Kiyo ; 61(7): 293-8, 2015 Jul.
Artigo em Japonês | MEDLINE | ID: mdl-26278216

RESUMO

Primary mucosa-associated lymphoid tissue (MALT) lymphoma of the prostate is rare. MALT lymphoma with large cell transformation like a diffuse large B-cell lymphoma (DLBCL) of the prostate is extremely rare. To the best of our knowledge, only one case has been previously reported. A 65-year-old man with difficulty on urination was referred to our department, in April 2014, because of abnormal findings of magnetic resonance imaging (MRI) and positron emission tomography-computed tomography imaging. Routine laboratory tests including prostate specific antigen and soluble interletkin-2 recepter were within normal limits, and the physical examination was unremarkable. In July 2007 and August 2009, he was submitted for a transrectal prostate biopsy, and then a histological examination for chronic prostatitis. In addition to the biopsy, transurethral resection of the prostate was performed. Histological examination revealed primary MALT lymphoma with large cell transformation of the prostate. Complete clinical investigation, including bone marrow biopsy, did not show any involvement of other sites by lymphoma, he received 3 cycles of chemotherapy consisting of rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisone (R-CHOP) followed by radiation therapy with a total dose of 46 Gy. The patient has been in complete remission for 6 months after the chemoradiation therapy.


Assuntos
Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Linfoma de Zona Marginal Tipo Células B/terapia , Neoplasias da Próstata/terapia , Idoso , Anticorpos Monoclonais Murinos/uso terapêutico , Biópsia , Quimiorradioterapia , Ciclofosfamida/uso terapêutico , Doxorrubicina/uso terapêutico , Humanos , Linfoma de Zona Marginal Tipo Células B/diagnóstico , Imageamento por Ressonância Magnética , Masculino , Prednisona/uso terapêutico , Neoplasias da Próstata/patologia , Rituximab , Vincristina/uso terapêutico
11.
Biol Blood Marrow Transplant ; 20(5): 684-9, 2014 May.
Artigo em Inglês | MEDLINE | ID: mdl-24492141

RESUMO

The number of elderly patients with diffuse large B cell lymphoma (DLBCL) continues to increase but the data regarding autologous stem cell transplantation (ASCT) for elderly patients are limited. We analyzed 484 patients, ages 60 years or over, diagnosed with relapsed/refractory DLBCL who received ASCT from 1993 to 2010 in the Japan Society for Hematopoietic Cell Transplantation database. Median age was 64 years (range, 60 to 78). To evaluate the impact of age at ASCT, patients were classified into 3 groups: those between the ages of 60 to 64, 65 to 69, and 70 years or over. Overall nonrelapse mortality (NRM) at day 100, 1 year, and 2 years was 4.1%, 5.9% and 7.7%, respectively. NRM did not significantly differ among age groups (P = .60). Two-year progression-free survival (PFS) and overall survival (OS) were 48% and 58%, respectively. PFS and OS were significantly longer in patients 60 to 64 years old; however, the survival rate was acceptable even in those 70 or over, with a 2-year OS of 46%. ASCT is feasible in selected elderly patients and age alone should not be a contraindication for ASCT. Eligibility should be individualized and identification of a subset of elderly patients at high risk of treatment-related morbidity or mortality warrants investigation.


Assuntos
Protocolos de Quimioterapia Combinada Antineoplásica , Transplante de Células-Tronco Hematopoéticas , Linfoma Difuso de Grandes Células B/terapia , Idoso , Carboplatina/uso terapêutico , Ciclofosfamida/uso terapêutico , Citarabina/uso terapêutico , Etoposídeo/uso terapêutico , Feminino , Humanos , Linfoma Difuso de Grandes Células B/imunologia , Linfoma Difuso de Grandes Células B/mortalidade , Linfoma Difuso de Grandes Células B/patologia , Masculino , Melfalan/uso terapêutico , Pessoa de Meia-Idade , Compostos de Nitrosoureia/uso terapêutico , Recidiva , Estudos Retrospectivos , Análise de Sobrevida , Transplante Autólogo
12.
Leuk Res Rep ; 2(1): 36-8, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-24371775

RESUMO

We experienced a patient with angioimmunoblastic T-cell lymphoma (AITL) without Epstein-Barr virus-positive B (EBV-B) cells at initial presentation who progressed to AITL with expansion of EBV-B cells at relapse. Based on the results of repeated biopsy, the patient was successfully treated with rituximab in combination with chemotherapy at relapse. A repeat biopsy may be necessary to determine the optimum therapeutic strategy at relapse, particularly for patients with suspected expansion of B cell and/or EBV-B cells. Although a recent report found no significant prognostic advantage of rituximab, it is one of the active drugs for selected patients with AITL.

15.
J Clin Oncol ; 29(31): e769-71, 2011 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-21947830
16.
J Am Acad Dermatol ; 61(6): 1070-5, 2009 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-19632739

RESUMO

Schnitzler syndrome is a rare condition defined by chronic urticaria, osteosclerotic bone lesions, and monoclonal IgM gammopathy. Schnitzler syndrome can precede the onset of a true lymphoproliferative disorder including Waldenström macroglobulinemia and rarely systemic marginal zone B-cell lymphoma. We describe a case of intractable chronic urticaria accompanied by a retroperitoneal neoplasm. IgM monoclonal gammopathy, lumber pain, intermittent fever, and elevation of C-reactive protein were the clues for the diagnosis of Schnitzler syndrome. An evaluation for malignancy using systemic computed tomography scan and fluorodeoxyglucose positron emission tomography revealed the retroperitoneal tumor, and a subsequent bone-marrow aspirate confirmed the diagnosis of B-cell lymphoma. Combined rituximab and radiotherapy ameliorated the skin symptoms. This case indicates that a detailed search for malignant neoplasms might be required for the long-term management of Schnitzler syndrome, and that B-cell lymphomas may contribute to the pathogenesis of this condition.


Assuntos
Anticorpos Monoclonais/uso terapêutico , Antineoplásicos/uso terapêutico , Linfoma de Células B/tratamento farmacológico , Linfoma de Células B/radioterapia , Neoplasias Retroperitoneais/radioterapia , Síndrome de Schnitzler/complicações , Urticária/complicações , Idoso , Anticorpos Monoclonais Murinos , Terapia Combinada , Feminino , Humanos , Linfoma de Células B/complicações , Neoplasias Retroperitoneais/tratamento farmacológico , Rituximab , Síndrome de Schnitzler/diagnóstico
17.
Int J Clin Oncol ; 14(2): 150-8, 2009 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-19390947

RESUMO

BACKGROUND: We compared standardized uptake values (SUVs) on positron emission tomography with a glucose analog, 2-[F-18] fluoro-2-deoxy-D-glucose (FDG-PET) and serum soluble interleukin-2 receptor (sIL-2R) values in patients with non-Hodgkin's lymphoma (NHL) in the pre-, mid- (after three or four cycles), and post-treatment periods of chemotherapy (pre, mid, and post, respectively), and we examined whether the SUV was a useful tumor marker for NHL. METHODS: The SUVs on PET and sIL-2R values were retrospectively evaluated based on all the clinical information available in 40 patients (31 in pre, 24 in mid, and 24 in the post periods). Patients in complete remission status were classified as group A and those with active residual disease in the mid and post periods were classified as group B. RESULTS: In pre, the SUV and sIL-2R values exhibited sensitivity of 100% and 84%, respectively. In mid, the SUV was lower in group A than in group B, while sIL-2R was not different. The SUV yielded better specificity than sIL-2R (88% vs. 25%, respectively), though the difference was not significant. In mid, the SUV in patients later assigned to group A in post was lower than than the SUV in group B, whereas sIL-2R was not different. In post, the specificity and accuracy of SUV were better than those of sIL-2R (95 vs. 47%, and 96 vs. 58%, respectively). Both the SUV and sIL-2R were lower in group A than in group B. CONCLUSION: The SUV on PET was better than the serum sIL-2R as a marker to evaluate the disease status of NHL, and was considered to be a useful tumor marker for NHL.


Assuntos
Fluordesoxiglucose F18 , Linfoma não Hodgkin/diagnóstico por imagem , Tomografia por Emissão de Pósitrons , Compostos Radiofarmacêuticos , Receptores de Interleucina-2/sangue , Idoso , Feminino , Humanos , Linfoma não Hodgkin/sangue , Linfoma não Hodgkin/tratamento farmacológico , Masculino , Pessoa de Meia-Idade
18.
Rinsho Ketsueki ; 49(8): 664-7, 2008 Aug.
Artigo em Japonês | MEDLINE | ID: mdl-18800617

RESUMO

A 54-year-old man, who had been diagnosed with Loeys-Dietz syndrome based on his past history, family history, clinical findings, and the presence of a gene mutation, was referred to our hospital because of easy fatigability. Anemia, thrombocytopenia, and blasts in his peripheral blood were noted, and 31.4% blasts were found in a bone marrow aspiration. The blasts were positive for myeloperoxidase and esterase staining. Furthermore, karyotype analysis of bone marrow cells showed t(11;19)(q23;p13.1) and MLL abnormality was detected on RT-PCR A diagnosis of acute myeloid leukemia (M4) with 11q23 (MLL) abnormality was made. Loeys-Dietz syndrome is a Marfan-like congenital connective tissue disorder caused by a heterozygous missense mutation of a TGF-beta receptor I or II gene. The TGF-beta family inhibits the proliferation of normal epithelial cells and induces apoptosis, and is therefore known as a tumor suppressor factor. In this article, we discussed the association between Loeys-Dietz syndrome with a TGF-beta receptor gene mutation and cancer.


Assuntos
Leucemia Mieloide Aguda/etiologia , Síndrome de Marfan/complicações , Síndrome de Marfan/genética , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Citarabina/administração & dosagem , Humanos , Idarubicina/administração & dosagem , Leucemia Mieloide Aguda/diagnóstico , Leucemia Mieloide Aguda/tratamento farmacológico , Leucemia Mieloide Aguda/genética , Masculino , Pessoa de Meia-Idade , Mutação de Sentido Incorreto , Receptores de Fatores de Crescimento Transformadores beta/genética , Indução de Remissão , Translocação Genética
19.
Oncogene ; 24(55): 8144-53, 2005 Dec 08.
Artigo em Inglês | MEDLINE | ID: mdl-16091740

RESUMO

FLT3 tyrosine kinase domain (TKD) mutations are detected in approximately 7% of acute myeloid leukemia patients, and suggested to correlate with poor prognosis and confer resistance to FLT3 inhibitors. To explore activation mechanism of FLT3 TKD mutation, we analysed critical tyrosine residues for the constitutive activation and downstream signaling of the mutant by generating a series of single Tyr --> Phe substitution mutant of all 22 cytoplasmic tyrosine residues of murine FLT3 TKD-mutant (mFLT3Asp838Val). Tyr845Phe, Tyr892Phe and Tyr922Phe substitutions suppressed the phosphorylation of mFLT3Asp838Val itself, the activation of Erk1/2, STAT3 and STAT5, and the factor-independent cell proliferation and survival. In contrast, these three Tyr --> Phe mutations partially suppressed but maintained the ligand-dependent activation and anti-apoptotic activity of wild-type FLT3, suggesting that these tyrosine residues were more critical for the constitutive activation and signaling of mFLT3Asp838Val. These three Tyr --> Phe mutations also inhibited the constitutive activation of other FLT3 mutants bearing internal tandem duplication, Asp838Tyr or Ile839del. The suppression of mFLT3Asp838Val activation and signaling by these substitutions was partially recovered by shifting the culture temperature from 37 to 33 degrees C, or by the introduction of Cdc37 and Hsp90. Taken together, Tyr845, Tyr892 and Tyr922 are the critical residues in mFLT3Asp838Val activation, possibly through stabilizing the active conformation of mFLT3Asp838Val.


Assuntos
Substituição de Aminoácidos , Tirosina , Tirosina Quinase 3 Semelhante a fms/genética , Tirosina Quinase 3 Semelhante a fms/metabolismo , Animais , Divisão Celular , Linhagem Celular , Sobrevivência Celular , Ativação Enzimática , Rim , Camundongos , Fenilalanina , Polimorfismo de Nucleotídeo Único , Proteínas Recombinantes/metabolismo , Transfecção
20.
J Biol Chem ; 279(24): 24986-93, 2004 Jun 11.
Artigo em Inglês | MEDLINE | ID: mdl-15067010

RESUMO

Notch and HOXB4 have been reported to expand hematopoietic stem cells (HSCs) in vitro. However, their critical effector molecules remain undetermined. We found that the expression of c-myc, cyclin D2, cyclin D3, cyclin E, and E2F1 was induced or enhanced during Notch1- or HOXB4-induced self-renewal of murine HSCs. Since c-Myc can act as a primary regulator of G(1)/S transition, we examined whether c-Myc alone can induce self-renewal of HSCs. In culture with stem cell factor, FLT3 ligand, and IL-6, a 4-hydroxytamoxifen-inducible form of c-Myc (Myc/ERT) enabled murine Lin(-)Sca-1(+) HSCs to proliferate with the surface phenotype compatible with HSCs for more than 28 days. c-Myc activated by 4-hydroxytamoxifen augmented telomerase activities and increased the number of CFU-Mix about 2-fold in colony assays. Also, in reconstitution assays, HSCs expanded by c-Myc could reconstitute hematopoiesis for more than 6 months. As for the mechanism of c-myc induction by Notch1, we found that activated forms of Notch1 (NotchIC) and its downstream effector recombination signal-binding protein-J kappa (RBP-VP16) can activate the c-myc promoter through the element between -195 bp and -161 bp by inducing the DNA-binding complex. Together, these results suggest that c-Myc can support self-renewal of HSCs as a downstream mediator of Notch and HOXB4.


Assuntos
Células-Tronco Hematopoéticas/fisiologia , Proteínas Proto-Oncogênicas c-myc/fisiologia , Tamoxifeno/análogos & derivados , Animais , Divisão Celular , Ciclina D1/genética , Proteínas de Homeodomínio/fisiologia , Humanos , Camundongos , Camundongos Endogâmicos C57BL , Regiões Promotoras Genéticas , Receptor Notch1 , Receptores de Superfície Celular/fisiologia , Tamoxifeno/farmacologia , Fatores de Transcrição/fisiologia
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