Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 100
Filtrar
4.
Blood Cancer J ; 14(1): 1, 2024 01 04.
Artigo em Inglês | MEDLINE | ID: mdl-38177095

RESUMO

Classical myeloproliferative neoplasms (MPNs) are characterized by the proliferation of myeloid cells and the risk of transformation into myelofibrosis or acute myeloid leukemia (AML) and TP53 mutations in MPN patients are linked to AML. However, JAK2V617F has been reported to impact the TP53 response to DNA damage, suggesting potential overlapping role of TP53 inactivation in MPN. We established a mouse model showing that JAK2V617F/Vav-Cre/Trp53-/- mice displayed a similar phenotype to JAK2V617F/Vav-Cre mice, but their proliferation was outcompeted in competitive grafts. RNA-Seq revealed that half of the genes affected by JAK2V617F were affected by p53-inactivation, including the interferon pathway. To validate this finding, mice were repopulated with a mixture of wild-type and JAK2V617F (or JAK2V617F/Vav-Cre/Trp53-/-) cells and treated with pegylated interferonα. JAK2V617F-reconstituted mice entered complete hematological remission, while JAK2V617F/Vav-Cre /Trp53-/--reconstituted mice did not, confirming that p53 loss induced interferon-α resistance. KEGG and Gene Ontology analyses of common deregulated genes showed that these genes were mainly implicated in cytokine response, proliferation, and leukemia evolution, illustrating that in this mouse model, the development of MPN is not affected by TP53 inactivation. Taken together, our results show that many genetic modifications induced by JAK2V617F are influenced by TP53, the MPN phenotype may not be. Trp53 loss alone is insufficient to induce rapid leukemic transformation in steady-state hematopoiesis in JAK2V617F MPN, and Trp53 loss may contribute to interferon resistance in MPN.


Assuntos
Leucemia Mieloide Aguda , Transtornos Mieloproliferativos , Humanos , Camundongos , Animais , Proteína Supressora de Tumor p53/genética , Janus Quinase 2/genética , Janus Quinase 2/metabolismo , Transtornos Mieloproliferativos/tratamento farmacológico , Transtornos Mieloproliferativos/genética , Mutação , Interferon-alfa/farmacologia , Genômica
6.
Leukemia ; 38(2): 326-339, 2024 02.
Artigo em Inglês | MEDLINE | ID: mdl-38148396

RESUMO

Current recommended risk scores to predict thrombotic events associated with myeloproliferative neoplasms (MPN) do not discriminate between arterial and venous thrombosis despite their different physiopathology. To define novel stratification systems, we delineated a comprehensive landscape of MPN associated thrombosis across a large long-term follow-up MPN cohort. Prior arterial thrombosis, age >60 years, cardiovascular risk factors and presence of TET2 or DNMT3A mutations were independently associated with arterial thrombosis in multivariable analysis. ARTS, an ARterial Thrombosis Score, based on these four factors, defined low- (0.37% patients-year) and high-risk (1.19% patients-year) patients. ARTS performance was superior to the two-tiered conventional risk stratification in our training cohort, across all MPN subtypes, as well as in two external validation cohorts. Prior venous thrombosis and presence of a JAK2V617F mutation with a variant allelic frequency ≥50% were independently associated with venous thrombosis. The discrimination potential of VETS, a VEnous Thrombosis Score based on these two factors, was poor, similar to the two-tiered conventional risk stratification. Our study pinpoints arterial and venous thrombosis clinico-molecular differences and proposes an arterial risk score for more accurate patients' stratification. Further improvement of venous risk scores, accounting for additional factors and considering venous thrombosis as a heterogeneous entity is warranted.


Assuntos
Transtornos Mieloproliferativos , Neoplasias , Trombose , Trombose Venosa , Humanos , Pessoa de Meia-Idade , Neoplasias/complicações , Trombose Venosa/genética , Trombose/genética , Trombose/complicações , Mutação , Transtornos Mieloproliferativos/complicações , Transtornos Mieloproliferativos/genética , Fatores de Risco , Janus Quinase 2/genética , Medição de Risco
8.
Leukemia ; 37(6): 1287-1297, 2023 06.
Artigo em Inglês | MEDLINE | ID: mdl-37100881

RESUMO

Heterozygous mutation targeting proline 95 in Serine/Arginine-rich Splicing Factor 2 (SRSF2) is associated with V617F mutation in Janus Activated Kinase 2 (JAK2) in some myeloproliferative neoplasms (MPNs), most commonly primary myelofibrosis. To explore the interaction of Srsf2P95H with Jak2V617F, we generated Cre-inducible knock-in mice expressing these mutants under control of the stem cell leukemia (Scl) gene promoter. In transplantation experiments, Srsf2P95H unexpectedly delayed myelofibrosis induced by Jak2V617F and decreased TGFß1 serum level. Srsf2P95H reduced the competitiveness of transplanted Jak2V617F hematopoietic stem cells while preventing their exhaustion. RNA sequencing of sorted megakaryocytes identified an increased number of splicing events when the two mutations were combined. Focusing on JAK/STAT pathway, Jak2 exon 14 skipping was promoted by Srsf2P95H, an event detected in patients with JAK2V617F and SRSF2P95 co-mutation. The skipping event generates a truncated inactive JAK2 protein. Accordingly, Srsf2P95H delays myelofibrosis induced by the thrombopoietin receptor agonist Romiplostim in Jak2 wild-type animals. These results unveil JAK2 exon 14 skipping promotion as a strategy to reduce JAK/STAT signaling in pathological conditions.


Assuntos
Transplante de Células-Tronco Hematopoéticas , Transtornos Mieloproliferativos , Mielofibrose Primária , Animais , Camundongos , Janus Quinase 2/genética , Janus Quinases/genética , Mutação , Transtornos Mieloproliferativos/genética , Mielofibrose Primária/genética , Proteínas de Ligação a RNA/genética , Transdução de Sinais , Fatores de Transcrição STAT/genética
9.
Leukemia ; 37(5): 957-963, 2023 05.
Artigo em Inglês | MEDLINE | ID: mdl-37002477

RESUMO

Myeloproliferative neoplasms are characterized by the acquisition at the hematopoietic stem cell level of driver mutations targeting the JAK/STAT pathway. In addition, they also often exhibit additional mutations targeting various pathways such as intracellular signalling, epigenetics, mRNA splicing or transcription. The natural history of myeloproliferative neoplasms is usually marked by a chronic phase of variable duration depending on the disease subtype, which can be followed by an accelerated phase or transformation towards more aggressive diseases such as myelofibrosis or acute leukemia. Besides, recent studies revealed important new information about the rates and mechanisms of sequential acquisition and selection of mutations in hematopoietic cells of myeloproliferative neoplasms. Better understanding of these events has been made possible in large part with the help of novel techniques that are now available to precisely decipher at the single cell level both the clonal architecture and the mutation-induced cell modifications. In this review, we will summarize the most recent knowledge about the mechanisms leading to clonal selection, how clonal architecture complexity can explain disease heterogeneity, and the impact of clonal evolution on clinical evolution.


Assuntos
Leucemia Mieloide Aguda , Transtornos Mieloproliferativos , Humanos , Janus Quinases/metabolismo , Transdução de Sinais , Fatores de Transcrição STAT/metabolismo , Transtornos Mieloproliferativos/genética , Transtornos Mieloproliferativos/metabolismo , Mutação , Evolução Clonal
10.
Br J Haematol ; 201(2): 234-248, 2023 04.
Artigo em Inglês | MEDLINE | ID: mdl-36546586

RESUMO

The human homologues of murine double minute 2 (MDM2) and 4 (MDM4) negatively regulate p53 tumour suppressor activity and are reported to be frequently overexpressed in human malignancies, prompting clinical trials with drugs that prevent interactions between MDM2/MDM4 and p53. Bone marrow samples from 111 patients with acute myeloblastic leukaemia, myelodysplastic syndrome or chronic myelomonocytic leukaemia were examined for protein (fluorescence-activated cell sorting) and messenger RNA (mRNA) expression (quantitative polymerase chain reaction) of MDM2, MDM4 and tumour protein p53 (TP53). Low protein expression of MDM2 and MDM4 was observed in immature cells from patients with excess of marrow blasts (>5%) compared with CD34+ /CD45low cells from healthy donors and patients without excess of marrow blasts (<5%). The mRNA levels were indistinguishable in all samples examined regardless of disease status or blast levels. Low MDM2 and MDM4 protein expression were correlated with poor survival. These data show a poor correlation between mRNA and protein expression levels, suggesting that quantitative flow cytometry analysis of protein expression levels should be used to predict and validate the efficacy of MDM2 and MDM4 inhibitors. These findings show that advanced disease is associated with reduced MDM2 and MDM4 protein expression and indicate that the utility of MDM2 and MDM4 inhibitors may have to be reconsidered in the treatment of advanced myeloid malignancies.


Assuntos
Leucemia Mieloide Aguda , Síndromes Mielodisplásicas , Humanos , Camundongos , Animais , Proteínas Proto-Oncogênicas c-mdm2/genética , Proteínas Proto-Oncogênicas c-mdm2/metabolismo , Proteínas Proto-Oncogênicas/genética , Proteína Supressora de Tumor p53/genética , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Leucemia Mieloide Aguda/genética , Síndromes Mielodisplásicas/genética , Proteínas de Ciclo Celular/genética , Proteínas de Ciclo Celular/metabolismo
11.
Br J Haematol ; 200(2): 175-186, 2023 01.
Artigo em Inglês | MEDLINE | ID: mdl-36214090

RESUMO

Superior rates of deep molecular response (DMR) have been reported with the combination of tyrosine kinase inhibitors and pegylated-interferon-alpha (Peg-IFN) in patients with newly diagnosed chronic phase-chronic myeloid leukaemia (CP-CML). In this setting, this study investigated the efficacy and safety of dasatinib combined to Peg-IFN-α2b (Dasa-PegIFN, NCT01872442). A total of 79 patients (age ≤65 years) started dasatinib; 61 were eligible for Peg-IFNα-2b add-on therapy at month 3 for a maximum 21-months duration. Dasatinib was continued thereafter. The primary endpoint was the cumulative rate of molecular response 4.5 log (MR4.5 ) by 12 months. The results are reported for the 5-year duration of the study. Grade 3 neutropenia was frequent with the combination but did not induce severe infection (one of grade 3). Other adverse events were generally low grade (4% of grade 3-4) and expected. Seventy-nine per cent and 61% of patients continued the Peg-IFN until months 12 and 24, respectively. Overall, at these time points, MR4.5 rates were 25% and 38%, respectively. Thereafter, 32% and 46% of patients achieved a sustained (≥2 years) MR4.5 or MR4 , respectively. This work established the feasibility and high rates of achievement of early and sustained DMR (a prerequisite for treatment-free-remission) with dasatinib and Peg-IFNα-2b combination as initial therapy.


Assuntos
Interferon-alfa , Leucemia Mieloide de Fase Crônica , Humanos , Idoso , Dasatinibe/efeitos adversos , Interferon-alfa/efeitos adversos , Leucemia Mieloide de Fase Crônica/tratamento farmacológico , Polietilenoglicóis/efeitos adversos , Resultado do Tratamento
12.
Leuk Lymphoma ; 63(13): 3175-3180, 2022 12.
Artigo em Inglês | MEDLINE | ID: mdl-36054826

RESUMO

Musculoskeletal (MSK) pains have been reported during TKI treatment or after its discontinuation in patients with chronic myeloid leukemia (CML). We hypothesized that MSK pains originate from calcific tendinopathy according to preliminary clinical observations. We conducted a retrospective study including CML patients divided into three groups: patients with MSK pain during TKI treatment; asymptomatic patients during TKI treatment; patients with MSK pain after TKI discontinuation. Patients with MSK pain were clinically evaluated, and the presence of calcific deposits was assessed in X-rays of both shoulders and pelvis. Forty-five patients were included; 14 described MSK pain during TKI treatment and 12 after TKI discontinuation. A diagnosis of rotator cuff tendinopathy was retained for 57.7% of patients and of gluteus tendinopathy in 19.2%. The prevalence of calcifications in shoulders and/or hips was 64.3% in symptomatic patients receiving TKIs, 63.2% in asymptomatic patients and 75.0% in patients with MSK pain after TKI treatment.


Assuntos
Leucemia Mielogênica Crônica BCR-ABL Positiva , Tendinopatia , Humanos , Estudos Retrospectivos , Tendinopatia/etiologia , Tendinopatia/induzido quimicamente , Leucemia Mielogênica Crônica BCR-ABL Positiva/tratamento farmacológico , Inibidores de Proteínas Quinases/efeitos adversos , Dor/induzido quimicamente , Dor/tratamento farmacológico
13.
Blood Adv ; 6(17): 5171-5183, 2022 09 13.
Artigo em Inglês | MEDLINE | ID: mdl-35802458

RESUMO

Myeloproliferative neoplasms (MPNs) are uncommon in children/young adults. Here, we present data on unselected patients diagnosed before 25 years of age included from 38 centers in 15 countries. Sequential patients were included. We identified 444 patients, with median follow-up 9.7 years (0-47.8). Forty-nine (11.1%) had a history of thrombosis at diagnosis, 49 new thrombotic events were recorded (1.16% patient per year [pt/y]), perihepatic vein thromboses were most frequent (47.6% venous events), and logistic regression identified JAK2V617F mutation (P = .016) and hyperviscosity symptoms (visual disturbances, dizziness, vertigo, headache) as risk factors (P = .040). New hemorrhagic events occurred in 44 patients (9.9%, 1.04% pt/y). Disease transformation occurred in 48 patients (10.9%, 1.13% pt/y), usually to myelofibrosis (7.5%) with splenomegaly as a novel risk factor for transformation in essential thrombocythemia (ET) (P= .000) in logistical regression. Eight deaths (1.8%) were recorded, 3 after allogeneic stem cell transplantation. Concerning conventional risk scores: International Prognostic Score for Essential Thrombocythemia-Thrombosis and new International Prognostic Score for Essential Thrombocythemia-Thrombosis differentiated ET patients in terms of thrombotic risk. Both scores identified high-risk patients with the same median thrombosis-free survival of 28.5 years. No contemporary scores were able to predict survival for young ET or polycythemia vera patients. Our data represents the largest real-world study of MPN patients age < 25 years at diagnosis. Rates of thrombotic events and transformation were higher than expected compared with the previous literature. Our study provides new and reliable information as a basis for prospective studies, trials, and development of harmonized international guidelines for the specific management of young patients with MPN.


Assuntos
Transtornos Mieloproliferativos , Policitemia Vera , Mielofibrose Primária , Trombocitemia Essencial , Trombose , Adulto , Criança , Humanos , Transtornos Mieloproliferativos/complicações , Transtornos Mieloproliferativos/diagnóstico , Transtornos Mieloproliferativos/epidemiologia , Policitemia Vera/complicações , Mielofibrose Primária/genética , Estudos Prospectivos , Trombose/etiologia , Adulto Jovem
14.
Int J Mol Sci ; 23(3)2022 Jan 18.
Artigo em Inglês | MEDLINE | ID: mdl-35162937

RESUMO

Myeloproliferative neoplasms (MPN) are a group of blood cancers in which the bone marrow (BM) produces an overabundance of erythrocyte, white blood cells, or platelets. Philadelphia chromosome-negative MPN has three subtypes, including polycythemia vera (PV), essential thrombocythemia (ET), and primary myelofibrosis (PMF). The over proliferation of blood cells is often associated with somatic mutations, such as JAK2, CALR, and MPL. JAK2V617F is present in 95% of PV and 50-60% of ET and PMF. Based on current molecular dynamics simulations of full JAK2 and the crystal structure of individual domains, it suggests that JAK2 maintains basal activity through self-inhibition, whereas other domains and linkers directly/indirectly enhance this self-inhibited state. Nevertheless, the JAK2V617F mutation is not the only determinant of MPN phenotype, as many normal individuals carry the JAK2V617F mutation without a disease phenotype. Here we review the major MPN phenotypes, JAK-STAT pathways, and mechanisms of development based on structural biology, while also describing the impact of other contributing factors such as gene mutation allele burden, JAK-STAT-related signaling pathways, epigenetic modifications, immune responses, and lifestyle on different MPN phenotypes. The cross-linking of these elements constitutes a complex network of interactions and generates differences in individual and cellular contexts that determine the phenotypic development of MPN.


Assuntos
Substituição de Aminoácidos , Janus Quinase 2/metabolismo , Transtornos Mieloproliferativos/patologia , Epigênese Genética , Humanos , Janus Quinase 2/química , Janus Quinase 2/genética , Sistema de Sinalização das MAP Quinases , Modelos Moleculares , Transtornos Mieloproliferativos/genética , Domínios Proteicos
15.
Blood Adv ; 6(9): 2813-2823, 2022 05 10.
Artigo em Inglês | MEDLINE | ID: mdl-35030630

RESUMO

The mechanisms of transformation of chronic myeloproliferative neoplasms (MPN) to leukemia are largely unknown, but TP53 mutations acquisition is considered a key event in this process. p53 is a main tumor suppressor, but mutations in this protein per se do not confer a proliferative advantage to the cells, and a selection process is needed for the expansion of mutant clones. MDM2 inhibitors may rescue normal p53 from degradation and have been evaluated in a variety of cancers with promising results. However, the impact of these drugs on TP53-mutated cells is underexplored. We report herein evidence of a direct effect of MDM2 inhibition on the selection of MPN patients' cells harboring TP53 mutations. To decipher whether these mutations can arise in a specific molecular context, we used a DNA single-cell approach to determine the clonal architecture of TP53-mutated cells. We observed that TP53 mutations are late events in MPN, mainly occurring in the driver clone, whereas clonal evolution frequently consists of sequential branching instead of linear consecutive acquisition of mutations in the same clone. At the single-cell level, the presence of additional mutations does not influence the selection of TP53 mutant cells by MDM2 inhibitor treatment. Also, we describe an in vitro test allowing to predict the emergence of TP53 mutated clones. Altogether, this is the first demonstration that a drug treatment can directly favor the emergence of TP53-mutated subclones in MPN.


Assuntos
Antineoplásicos , Transtornos Mieloproliferativos , Células Clonais/metabolismo , Humanos , Mutação , Transtornos Mieloproliferativos/genética , Proteínas Proto-Oncogênicas c-mdm2/genética , Proteínas Proto-Oncogênicas c-mdm2/metabolismo , Análise de Célula Única , Proteína Supressora de Tumor p53/genética , Proteína Supressora de Tumor p53/metabolismo
16.
Br J Haematol ; 196(3): 676-680, 2022 02.
Artigo em Inglês | MEDLINE | ID: mdl-34562020

RESUMO

We assessed the diagnostic performances of erythropoietin and JAK2 mutations in 1,090 patients with suspected polycythemia who were referred for red cell mass (RCM) measurement. In patients with a high haematocrit and/or haemoglobin level, a low erythropoietin level (<=3·3 mUI/ml) and JAK2 mutation showed comparable positive predictive value (PPV) for true polycythemia (RCM>=125%), 92·1% and 90% respectively. A very-low erythropoietin level (<=1·99 mUI/ml) had a PPV of 100% for polycythemia vera (PV) diagnosis. We confirmed the correlations between RCM, erythropoietin and JAK2 variant allelic frequency in PV patients. This study prompts the need to revisit the role of EPO in PV diagnostic criteria.


Assuntos
Eritropoetina/sangue , Janus Quinase 2/genética , Mutação , Policitemia Vera/sangue , Policitemia Vera/genética , Alelos , Substituição de Aminoácidos , Tomada de Decisão Clínica , Gerenciamento Clínico , Índices de Eritrócitos , Volume de Eritrócitos , Frequência do Gene , Estudos de Associação Genética , Predisposição Genética para Doença , Humanos , Volume Plasmático , Policitemia Vera/diagnóstico , Policitemia Vera/epidemiologia , Sensibilidade e Especificidade
17.
iScience ; 24(12): 103399, 2021 Dec 17.
Artigo em Inglês | MEDLINE | ID: mdl-34877482

RESUMO

We have reconciled steady-state and stress hematopoiesis in a single mathematical model based on murine in vivo experiments and with a focus on hematopoietic stem and progenitor cells. A phenylhydrazine stress was first applied to mice. A reduced cell number in each progenitor compartment was evidenced during the next 7 days through a drastic level of differentiation without proliferation, followed by a huge proliferative response in all compartments including long-term hematopoietic stem cells, before a return to normal levels. Data analysis led to the addition to the 6-compartment model, of time-dependent regulation that depended indirectly on the compartment sizes. The resulting model was finely calibrated using a stochastic optimization algorithm and could reproduce biological data in silico when applied to different stress conditions (bleeding, chemotherapy, HSC depletion). In conclusion, our multi-step and time-dependent model of immature hematopoiesis provides new avenues to a better understanding of both normal and pathological hematopoiesis.

20.
Blood Adv ; 5(5): 1442-1451, 2021 03 09.
Artigo em Inglês | MEDLINE | ID: mdl-33666653

RESUMO

We aimed to study the prognostic impact of the mutational landscape in primary and secondary myelofibrosis. The study included 479 patients with myelofibrosis recruited from 24 French Intergroup of Myeloproliferative Neoplasms (FIM) centers. The molecular landscape was studied by high-throughput sequencing of 77 genes. A Bayesian network allowed the identification of genomic groups whose prognostic impact was studied in a multistate model considering transitions from the 3 conditions: myelofibrosis, acute leukemia, and death. Results were validated using an independent, previously published cohort (n = 276). Four genomic groups were identified: patients with TP53 mutation; patients with ≥1 mutation in EZH2, CBL, U2AF1, SRSF2, IDH1, IDH2, NRAS, or KRAS (high-risk group); patients with ASXL1-only mutation (ie, no associated mutation in TP53 or high-risk genes); and other patients. A multistate model found that both TP53 and high-risk groups were associated with leukemic transformation (hazard ratios [HRs] [95% confidence interval], 8.68 [3.32-22.73] and 3.24 [1.58-6.64], respectively) and death from myelofibrosis (HRs, 3.03 [1.66-5.56] and 1.77 [1.18-2.67], respectively). ASXL1-only mutations had no prognostic value that was confirmed in the validation cohort. However, ASXL1 mutations conferred a worse prognosis when associated with a mutation in TP53 or high-risk genes. This study provides a new definition of adverse mutations in myelofibrosis with the addition of TP53, CBL, NRAS, KRAS, and U2AF1 to previously described genes. Furthermore, our results argue that ASXL1 mutations alone cannot be considered detrimental.


Assuntos
Mielofibrose Primária , Teorema de Bayes , Genômica , Humanos , Mutação , Mielofibrose Primária/diagnóstico , Mielofibrose Primária/genética , Prognóstico , Proteínas Repressoras/genética
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...