RESUMO
In chronic-phase chronic myeloid leukaemia (CP-CML), residual BCR-ABL1+ leukaemia stem cells are responsible for disease persistence despite TKI. Based on in vitro data, CHOICES (CHlorOquine and Imatinib Combination to Eliminate Stem cells) was an international, randomised phase II trial designed to study the safety and efficacy of imatinib (IM) and hydroxychloroquine (HCQ) compared with IM alone in CP-CML patients in major cytogenetic remission with residual disease detectable by qPCR. Sixty-two patients were randomly assigned to either arm. Treatment 'successes' was the primary end point, defined as ≥0.5 log reduction in 12-month qPCR level from trial entry. Selected secondary study end points were 24-month treatment 'successes', molecular response and progression at 12 and 24 months, comparison of IM levels, and achievement of blood HCQ levels >2000 ng/ml. At 12 months, there was no difference in 'success' rate (p = 0.58); MMR was achieved in 80% (IM) vs 92% (IM/HCQ) (p = 0.21). At 24 months, the 'success' rate was 20.8% higher with IM/HCQ (p = 0.059). No patients progressed. Seventeen serious adverse events, including four serious adverse reactions, were reported; diarrhoea occurred more frequently with combination. IM/HCQ is tolerable in CP-CML, with modest improvement in qPCR levels at 12 and 24 months, suggesting autophagy inhibition maybe of clinical value in CP-CML.
Assuntos
Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Análise Citogenética/métodos , Proteínas de Fusão bcr-abl/genética , Leucemia Mielogênica Crônica BCR-ABL Positiva/tratamento farmacológico , Idoso , Feminino , Seguimentos , Humanos , Hidroxicloroquina/administração & dosagem , Mesilato de Imatinib/administração & dosagem , Leucemia Mielogênica Crônica BCR-ABL Positiva/genética , Leucemia Mielogênica Crônica BCR-ABL Positiva/patologia , Masculino , Pessoa de Meia-Idade , Prognóstico , Estudos Retrospectivos , Taxa de SobrevidaRESUMO
The requirements for optimal biobanking from the point of view of the clinical partner can be highly variable. Depending on the material, processing, storage conditions, clinical data, and involvement of external partners, there will be special requirements for the participating clinician and specialist areas. What they all have in common is that the goal of any biobanking must be to improve clinical, translational, and basic research. While in the past biomaterials often had to be individually stored for each research project, modern biobanking offers decisive advantages: a comprehensive ethics vote fulfilling state-of-the-art data safety requirements, standardized processing and storage protocols, specialized biobank software for pseudonymization and localization, protection against power failures and defects of the equipment, centralized and sustainable storage, easy localization and return of samples, and their destruction or anonymization after completion of an individual project. In addition to this important pure storage function, central biobanking can provide a link to clinical data as well as the anonymous use of samples for project-independent research. Both biobank functions serve different purposes, are associated with specific requirements, and should be pursued in parallel. If successful, central biomaterial management can achieve a sustainable improvement of academic and non-academic biomedical research and the optimal use of resources. The close collaboration between clinicians and non-clinicians is a crucial prerequisite for this.
Assuntos
Bancos de Espécimes Biológicos , Pesquisa Biomédica , HematologiaRESUMO
T-cell prolymphocytic leukemia (T-PLL) is a rare and aggressive neoplasm of mature T-cells with an urgent need for rationally designed therapies to address its notoriously chemo-refractory behavior. The median survival of T-PLL patients is <2 years and clinical trials are difficult to execute. Here we systematically explored the diversity of drug responses in T-PLL patient samples using an ex vivo drug sensitivity and resistance testing platform and correlated the findings with somatic mutations and gene expression profiles. Intriguingly, all T-PLL samples were sensitive to the cyclin-dependent kinase inhibitor SNS-032, which overcame stromal-cell-mediated protection and elicited robust p53-activation and apoptosis. Across all patients, the most effective classes of compounds were histone deacetylase, phosphoinositide-3 kinase/AKT/mammalian target of rapamycin, heat-shock protein 90 and BH3-family protein inhibitors as well as p53 activators, indicating previously unexplored, novel targeted approaches for treating T-PLL. Although Janus-activated kinase-signal transducer and activator of transcription factor (JAK-STAT) pathway mutations were common in T-PLL (71% of patients), JAK-STAT inhibitor responses were not directly linked to those or other T-PLL-specific lesions. Overall, we found that genetic markers do not readily translate into novel effective therapeutic vulnerabilities. In conclusion, novel classes of compounds with high efficacy in T-PLL were discovered with the comprehensive ex vivo drug screening platform warranting further studies of synergisms and clinical testing.
Assuntos
Antineoplásicos/farmacologia , Biomarcadores Tumorais , Resistencia a Medicamentos Antineoplásicos , Ensaios de Seleção de Medicamentos Antitumorais , Ensaios de Triagem em Larga Escala , Leucemia Prolinfocítica de Células T/genética , Mutação , Idoso , Idoso de 80 Anos ou mais , Antineoplásicos/uso terapêutico , Ciclo Celular/genética , Linhagem Celular Tumoral , Aberrações Cromossômicas , Feminino , Expressão Gênica , Perfilação da Expressão Gênica , Humanos , Janus Quinases/metabolismo , Leucemia Prolinfocítica de Células T/tratamento farmacológico , Leucemia Prolinfocítica de Células T/metabolismo , Masculino , Pessoa de Meia-Idade , Terapia de Alvo Molecular , Oxazóis/farmacologia , Fenótipo , Inibidores de Proteínas Quinases/farmacologia , Fatores de Transcrição STAT/metabolismo , Tiazóis/farmacologiaAssuntos
Proteínas dos Microfilamentos/genética , Proteínas dos Microfilamentos/metabolismo , Mutação/genética , Proteínas de Neoplasias/genética , Proteínas de Neoplasias/metabolismo , Animais , Células-Tronco Embrionárias/metabolismo , Células-Tronco Hematopoéticas/metabolismo , Linfoma/metabolismo , Camundongos , Camundongos KnockoutAssuntos
Antígenos CD19/biossíntese , Leucemia-Linfoma Linfoblástico de Células Precursoras B/metabolismo , Leucemia-Linfoma Linfoblástico de Células Precursoras B/patologia , Animais , Linhagem Celular , Proliferação de Células/fisiologia , Técnicas de Silenciamento de Genes , Xenoenxertos , Humanos , Camundongos , Camundongos Endogâmicos NOD , Camundongos SCIDAssuntos
Transformação Celular Neoplásica/genética , Leucemia Mielogênica Crônica BCR-ABL Positiva/metabolismo , Leucemia Mielogênica Crônica BCR-ABL Positiva/patologia , Fosfoproteínas/metabolismo , Proteínas Adaptadoras de Transdução de Sinal , Animais , Modelos Animais de Doenças , Proteínas de Fusão bcr-abl/genética , Hidronefrose/etiologia , Leucemia Mielogênica Crônica BCR-ABL Positiva/genética , Camundongos , Camundongos TransgênicosRESUMO
BACKGROUND: Patients with Ph-negative myeloproliferative neoplasms (MPN), such as polycythemia vera (PV), essential thrombocythemia (ET), and primary myelofibrosis (PMF), are at increased risk for thrombosis/thromboembolism and major bleeding. Due to the morbidity and mortality of these events, antiplatelet and/or anticoagulant agents are commonly employed as primary and/or secondary prophylaxis. On the other hand, disease-related bleeding complications (i.e., from esophageal varices) are common in patients with MPN. This analysis was performed to define the frequency of such events, identify risk factors, and assess antiplatelet/anticoagulant therapy in a cohort of patients with MPN. METHODS: The MPN registry of the Study Alliance Leukemia is a non-interventional prospective study including adult patients with an MPN according to WHO criteria (2008). For statistical analysis, descriptive methods and tests for significant differences as well as contingency tables were used to identify the odds of potential risk factors for vascular events. RESULTS: MPN subgroups significantly differed in sex distribution, age at diagnosis, blood counts, LDH levels, JAK2V617F positivity, and spleen size (length). While most thromboembolic events occurred around the time of MPN diagnosis, one third of these events occurred after that date. Splanchnic vein thrombosis was most frequent in post-PV-MF and MPN-U patients. The chance of developing a thromboembolic event was significantly elevated if patients suffered from post-PV-MF (OR 3.43; 95% CI = 1.39-8.48) and splenomegaly (OR 1.76; 95% CI = 1.15-2.71). Significant odds for major bleeding were previous thromboembolic events (OR = 2.71; 95% CI = 1.36-5.40), splenomegaly (OR = 2.22; 95% CI 1.01-4.89), and the administration of heparin (OR = 5.64; 95% CI = 1.84-17.34). Major bleeding episodes were significantly less frequent in ET patients compared to other MPN subgroups. CONCLUSIONS: Together, this report on an unselected "real-world" cohort of German MPN patients reveals important data on the prevalence, diagnosis, and treatment of thromboembolic and major bleeding complications of MPN.
Assuntos
Coagulação Sanguínea/fisiologia , Hemorragia/fisiopatologia , Transtornos Mieloproliferativos/fisiopatologia , Sistema de Registros/estatística & dados numéricos , Trombose/fisiopatologia , Adulto , Idoso , Idoso de 80 Anos ou mais , Anticoagulantes/uso terapêutico , Coagulação Sanguínea/efeitos dos fármacos , Feminino , Alemanha/epidemiologia , Hemorragia/diagnóstico , Hemorragia/prevenção & controle , Humanos , Modelos Logísticos , Masculino , Pessoa de Meia-Idade , Transtornos Mieloproliferativos/tratamento farmacológico , Transtornos Mieloproliferativos/epidemiologia , Prevalência , Estudos Prospectivos , Esplenomegalia/diagnóstico , Esplenomegalia/fisiopatologia , Trombose/diagnóstico , Trombose/prevenção & controleRESUMO
The Philadelphia-negative myeloproliferative neoplasms (MPNs) are clonal disorders involving hematopoietic stem and progenitor cells and are associated with myeloproliferation, splenomegaly and constitutional symptoms. Similar signs and symptoms can also be found in patients with chronic inflammatory diseases, and inflammatory processes have been found to play an important role in the pathogenesis and progression of MPNs. Signal transduction pathways involving JAK1, JAK2, STAT3 and STAT5 are causally involved in driving both the malignant cells and the inflammatory process. Moreover, anti-inflammatory and immune-modulating drugs have been used successfully in the treatment of MPNs. However, to date, many unresoved issues remain. These include the role of somatic mutations that are present in addition to JAK2V617F, CALR and MPL W515 mutations, the interdependency of malignant and nonmalignant cells and the means to eradicate MPN-initiating and -maintaining cells. It is imperative for successful therapeutic approaches to define whether the malignant clone or the inflammatory cells or both should be targeted. The present review will cover three aspects of the role of inflammation in MPNs: inflammatory states as important differential diagnoses in cases of suspected MPN (that is, in the absence of a clonal marker), the role of inflammation in MPN pathogenesis and progression and the use of anti-inflammatory drugs for MPNs. The findings emphasize the need to separate the inflammatory processes from the malignancy in order to improve our understanding of the pathogenesis, diagnosis and treatment of patients with Philadelphia-negative MPNs.
Assuntos
Inflamação/tratamento farmacológico , Transtornos Mieloproliferativos/tratamento farmacológico , Neoplasias/patologia , Anti-Inflamatórios/uso terapêutico , Células Clonais/patologia , Humanos , Transtornos Mieloproliferativos/patologiaRESUMO
DNA methylation changes are a constant feature of acute myeloid leukemia. Hypomethylating drugs such as azacitidine are active in acute myeloid leukemia (AML) as monotherapy. Azacitidine monotherapy is not curative. The AML-AZA trial tested the hypothesis that DNA methyltransferase inhibitors such as azacitidine can improve chemotherapy outcome in AML. This randomized, controlled trial compared the efficacy of azacitidine applied before each cycle of intensive chemotherapy with chemotherapy alone in older patients with untreated AML. Event-free survival (EFS) was the primary end point. In total, 214 patients with a median age of 70 years were randomized to azacitidine/chemotherapy (arm-A) or chemotherapy (arm-B). More arm-A patients (39/105; 37%) than arm-B (25/109; 23%) showed adverse cytogenetics (P=0.057). Adverse events were more frequent in arm-A (15.44) versus 13.52 in arm-B, (P=0.26), but early death rates did not differ significantly (30-day mortality: 6% versus 5%, P=0.76). Median EFS was 6 months in both arms (P=0.96). Median overall survival was 15 months for patients in arm-A compared with 21 months in arm-B (P=0.35). Azacitidine added to standard chemotherapy increases toxicity in older patients with AML, but provides no additional benefit for unselected patients.
Assuntos
Antimetabólitos Antineoplásicos/uso terapêutico , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Azacitidina/uso terapêutico , Quimioterapia de Indução/métodos , Leucemia Mieloide Aguda/tratamento farmacológico , Idoso , Citarabina/uso terapêutico , Análise Citogenética , Daunorrubicina/uso terapêutico , Feminino , Humanos , Leucemia Mieloide Aguda/diagnóstico , Leucemia Mieloide Aguda/genética , Leucemia Mieloide Aguda/mortalidade , Masculino , Pessoa de Meia-Idade , Indução de Remissão , Análise de SobrevidaRESUMO
Chronic myeloid leukemia (CML) is driven by malignant stem cells that can persist despite therapy. We have identified Metastasis suppressor 1 (Mtss1/MIM) to be downregulated in hematopoietic stem and progenitor cells from leukemic transgenic SCLtTA/Bcr-Abl mice and in patients with CML at diagnosis, and Mtss1 was restored when patients achieved complete remission. Forced expression of Mtss1 decreased clonogenic capacity and motility of murine myeloid progenitor cells and reduced tumor growth. Viral transduction of Mtss1 into lineage-depleted SCLtTA/Bcr-Abl bone marrow cells decreased leukemic cell burden in recipients, and leukemogenesis was reduced upon injection of Mtss1-overexpressing murine myeloid 32D cells. Tyrosine kinase inhibitor (TKI) therapy and reversion of Bcr-Abl expression increased Mtss1 expression but failed to restore it to control levels. CML patient samples revealed higher DNA methylation of specific Mtss1 promoter CpG sites that contain binding sites for Kaiso and Rest transcription factors. In summary, we identified a novel tumor suppressor in CML stem cells that is downregulated by both Bcr-Abl kinase-dependent and -independent mechanisms. Restored Mtss1 expression markedly inhibits primitive leukemic cell biology in vivo, providing a therapeutic rationale for the Bcr-Abl-Mtss1 axis to target TKI-resistant CML stem cells in patients.
Assuntos
Movimento Celular , Proliferação de Células , Proteínas de Fusão bcr-abl/genética , Leucemia Mielogênica Crônica BCR-ABL Positiva/genética , Leucemia Mielogênica Crônica BCR-ABL Positiva/patologia , Proteínas dos Microfilamentos/metabolismo , Proteínas de Neoplasias/metabolismo , Animais , Apoptose , Western Blotting , Imunoprecipitação da Cromatina , Regulação Leucêmica da Expressão Gênica , Humanos , Camundongos , Camundongos Endogâmicos C3H , Camundongos Transgênicos , Proteínas dos Microfilamentos/genética , Proteínas de Neoplasias/genética , RNA Mensageiro/genética , Reação em Cadeia da Polimerase em Tempo Real , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Células Tumorais Cultivadas , Ensaios Antitumorais Modelo de XenoenxertoRESUMO
Telomere biology is frequently associated with disease evolution in human cancer and dysfunctional telomeres have been demonstrated to contribute to genetic instability. In BCR-ABL(+) chronic myeloid leukemia (CML), accelerated telomere shortening has been shown to correlate with leukemia progression, risk score and response to treatment. Here, we demonstrate that proliferation of murine CML-like bone marrow cells strongly depends on telomere maintenance. CML-like cells of telomerase knockout mice with critically short telomeres (CML-iG4) are growth retarded and proliferation is terminally stalled by a robust senescent cell cycle arrest. In sharp contrast, CML-like cells with pre-shortened, but not critically short telomere lengths (CML-G2) grew most rapidly and were found to express a specific 'telomere-associated secretory phenotype', comprising secretion of chemokines, interleukins and other growth factors, thereby potentiating oncogene-driven growth. Moreover, conditioned supernatant of CML-G2 cells markedly enhanced proliferation of CML-WT and pre-senescent CML-iG4 cells. Strikingly, a similar inflammatory mRNA expression pattern was found with disease progression from chronic phase to accelerated phase in CML patients. These findings demonstrate that telomere-induced senescence needs to be bypassed by leukemic cells in order to progress to blast crisis and provide a novel mechanism by which telomere shortening may contribute to disease evolution in CML.
Assuntos
Proliferação de Células , Proteínas de Fusão bcr-abl/metabolismo , Regulação Leucêmica da Expressão Gênica , Leucemia/patologia , Telômero/ultraestrutura , Animais , Apoptose , Células da Medula Óssea/citologia , Ciclo Celular , Linhagem Celular Tumoral , Senescência Celular , Quimiocinas/metabolismo , Citocinas/metabolismo , Progressão da Doença , Humanos , Inflamação/metabolismo , Leucemia/metabolismo , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , FenótipoAssuntos
Proteínas de Fusão Oncogênica/genética , Leucemia-Linfoma Linfoblástico de Células T Precursoras/diagnóstico , Leucemia-Linfoma Linfoblástico de Células T Precursoras/genética , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Evolução Fatal , Transplante de Células-Tronco Hematopoéticas , Humanos , Masculino , Mutação , Leucemia-Linfoma Linfoblástico de Células T Precursoras/terapia , Transplante Homólogo , Adulto JovemRESUMO
Mutations in the genetic sequence of the DNA de novo methyltransferase DNMT3A (DNA methyltransferase 3A) are found in many patients with acute myeloid leukemia (AML). They lead to dysfunction of DNMT3A protein and represent a marker for poor prognosis. Effects of genetic mutations can be mimicked by epigenetic modifications in the DNA methylation (DNAm) pattern. Using DNAm profiles of the Cancer Genome Atlas Research Network (TCGA), we identified aberrant hypermethylation at an internal promoter region of DNMT3A, which occurred in about 40% of AML patients. Bisulfite pyrosequencing assays designed for this genomic region validated hypermethylation specifically in a subset of our AML samples. High DNAm levels at this site are particularly observed in samples without genetic mutations in DNMT3A. Epimutations and mutations of DNMT3A were associated with related gene expression changes such as upregulation of the homeobox genes in HOXA and HOXB clusters. Furthermore, epimutations in DNMT3A were enriched in patients with poor or intermediate cytogenetic risk, and in patients with shorter event-free survival and overall survival (OS). Taken together, aberrant DNA hypermethylation within the DNMT3A gene, in analogy to DNMT3A mutations, is frequently observed in AML and both modifications seem to be useful for risk stratification or choice of therapeutic regimen.
Assuntos
Biomarcadores Tumorais/genética , DNA (Citosina-5-)-Metiltransferases/genética , Metilação de DNA , Epigênese Genética/genética , Genômica , Leucemia Mieloide Aguda/genética , Mutação/genética , DNA Metiltransferase 3A , Perfilação da Expressão Gênica , Humanos , Leucemia Mieloide Aguda/mortalidade , Análise de Sequência com Séries de Oligonucleotídeos , Prognóstico , RNA Mensageiro/genética , Reação em Cadeia da Polimerase em Tempo Real , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Taxa de SobrevidaRESUMO
BACKGROUND: Chemotherapy for elderly patients with acute myeloid leukemia (AML) results in a median overall survival (OS) of ≤ 1 year. Elderly patients often present with cardiac comorbidity. Gemtuzumab ozogamicin (GO) is active in elderly (≥ 60 years) patients with relapsed AML with low cardiac toxicity. PATIENTS AND METHODS: This randomized phase II study compared a standard combination of ara-C and daunorubicin (DNR; 7+3) versus ara-C plus gemtuzumab ozogamicin (7+GO) as the first course of induction therapy. Primary objectives were comparison of blast clearance on day 16, event-free survival (EFS), and remission duration. OS, complete remission (CR), and tolerability were secondary objectives. RESULTS: One hundred and nineteen patients with de novo AML, treatment-related AML, AML with a history of myelodysplastic syndrome (MDS), or high-risk MDS entered the study. Median age of 115 patients (intent-to-treat population) was 69 years. Protocol outlined a second course 7+3 for patients without blast clearance and two courses of high-dose ara-C consolidation upon CR. Both treatments were equally effective in blast clearance, CR, EFS, remission duration, or OS (median: 7+3, 9 months; 7+GO, 10 months). Induction death rate was higher in the GO group due to veno-occlusive disease. CONCLUSION: The study did not show significant superiority of 7+GO over standard 7+3.
Assuntos
Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Quimioterapia de Indução , Leucemia Mieloide Aguda/tratamento farmacológico , Idoso , Idoso de 80 Anos ou mais , Aminoglicosídeos/administração & dosagem , Anticorpos Monoclonais Humanizados/administração & dosagem , Protocolos de Quimioterapia Combinada Antineoplásica/efeitos adversos , Citarabina/administração & dosagem , Daunorrubicina/administração & dosagem , Intervalo Livre de Doença , Feminino , Gemtuzumab , Humanos , Leucemia Mieloide Aguda/mortalidade , Masculino , Pessoa de Meia-Idade , Análise de Sobrevida , Resultado do TratamentoRESUMO
Although BCR-ABL+ stem cells in chronic myeloid leukemia (CML) resist elimination by targeted pharmacotherapy in most patients, immunological graft-versus-leukemia effects can cure the disease. Besides cytotoxic T cells, natural killer (NK) cells may have a role in immune control of CML. Here, we explored the functionality of NK cells in CML patients and in a transgenic inducible BCR-ABL mouse model. Compared with controls, NK-cell proportions among lymphocytes were decreased at diagnosis of CML and did not recover during imatinib-induced remission for 10-34 months. Functional experiments revealed limited in vitro expansion of NK cells from CML patients and a reduced degranulation response to K562 target cells both at diagnosis and during imatinib therapy. Consistent with the results in human CML, relative numbers of NK1.1+ NK cells were reduced following induction of BCR-ABL expression in mice, and the defects persisted after BCR-ABL reversion. Moreover, target-induced degranulation by expanded BCR-ABL+ NK cells was compromised. We conclude that CML is associated with quantitative and functional defects within the NK-cell compartment, which is reproduced by induced BCR-ABL expression in mice. Further work will aim at identifying the mechanisms of NK-cell deficiency in CML and at developing strategies to exploit NK cells for immunotherapy.
Assuntos
Antineoplásicos/uso terapêutico , Proteínas de Fusão bcr-abl/genética , Células Matadoras Naturais/imunologia , Leucemia Mielogênica Crônica BCR-ABL Positiva/tratamento farmacológico , Leucemia Mielogênica Crônica BCR-ABL Positiva/imunologia , Piperazinas/uso terapêutico , Inibidores de Proteínas Quinases/uso terapêutico , Pirimidinas/uso terapêutico , Adolescente , Adulto , Idoso , Animais , Antineoplásicos/farmacologia , Benzamidas , Degranulação Celular/genética , Degranulação Celular/imunologia , Criança , Modelos Animais de Doenças , Humanos , Mesilato de Imatinib , Células K562 , Células Matadoras Naturais/efeitos dos fármacos , Células Matadoras Naturais/metabolismo , Leucemia Mielogênica Crônica BCR-ABL Positiva/genética , Camundongos , Camundongos Transgênicos , Pessoa de Meia-Idade , Piperazinas/farmacologia , Inibidores de Proteínas Quinases/farmacologia , Pirimidinas/farmacologia , Adulto JovemRESUMO
Spleen size ranks among the most important risk factors in chronic myeloid leukemia (CML), but the pathogenic mechanisms of splenic hematopoiesis in CML remain poorly defined. Here, we studied the biology of Bcr-Abl positive leukemia-initiating cells in the spleen, using an inducible transgenic mouse model of CML. Disease kinetics showed greater increases of immature leukemic cells in spleen vs bone marrow (BM). To assess how Bcr-Abl alters the behavior of spleen-derived CML cells, we transplanted these cells either before ('pre-uninduced') or 44 days after ('pre-induced') expression of the oncogene. Mice transplanted with pre-induced spleen cells showed significantly increased neutrophilia and splenomegaly compared with mice receiving pre-uninduced spleen cells, suggesting that Bcr-Abl expression in the donors had increased splenic tumor burden. However, pre-induction also altered the biology of these cells, as shown by a striking increase in erythropoietic potential. These results differ from those of BM-derived CML stem cells where pre-induction of Bcr-Abl had previously been shown to decrease disease transplantability. Moreover, splenic cells were less sensitive to imatinib than BM cells. In conclusion, Bcr-Abl alters the biology of splenic leukemic stem cells by a cell-autonomous mechanism, but the disease phenotype is also influenced by the microenvironment of these cells.
Assuntos
Células da Medula Óssea/patologia , Modelos Animais de Doenças , Leucemia Mielogênica Crônica BCR-ABL Positiva/patologia , Baço/patologia , Animais , Progressão da Doença , Citometria de Fluxo , Proteínas de Fusão bcr-abl/metabolismo , Camundongos , Camundongos Transgênicos , EsplenomegaliaAssuntos
Proteína alfa Estimuladora de Ligação a CCAAT/genética , Mutação em Linhagem Germinativa , Células-Tronco Hematopoéticas/metabolismo , Leucemia Mieloide Aguda/cirurgia , Síndromes Neoplásicas Hereditárias/genética , Transplante de Células-Tronco de Sangue Periférico , Adulto , Antecipação Genética , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Pré-Escolar , Terapia Combinada , Feminino , Células-Tronco Hematopoéticas/patologia , Humanos , Leucemia Mieloide Aguda/tratamento farmacológico , Leucemia Mieloide Aguda/genética , Segunda Neoplasia Primária/genética , Segunda Neoplasia Primária/cirurgia , Linhagem , Leucemia-Linfoma Linfoblástico de Células Precursoras , Recidiva , Terapia de Salvação , Sobreviventes , Transplante HomólogoRESUMO
Pim2 is a serine/threonine kinase expressed at high levels in several malignancies including acute leukemia. Pim2 protein is induced by oncogenic Fms-like tyrosine kinase-3 (Flt3)-internal tandem duplications (ITD), but not by Flt3 wild-type receptor (Flt3-Wt) in response to Flt3 ligand (FL). Here we show that Pim2 can complement Flt3-Wt signaling and induce transformation similar to Flt3-ITD in myeloid cells. Our data demonstrate that Pim2 is necessary but not sufficient for Flt3-ITD-induced transformation of 32D cells and primary bone marrow cells as assessed by colony assays. Pim2-induced clonogenic growth of FL-treated 32D-Flt3-Wt cells. Proliferation of 32D-Flt3-Wt cells was significantly enhanced in FL-treated Pim2-overexpressing cells. This increase was associated with enhanced S-phase cell cycle progression. Pim2-overexpressing cells were resistant to apoptosis induced by growth factor deprivation or treatment with tyrosine kinase inhibitor (PKC412). The Flt3 point mutant D835Y, which is not able to support colony growth of myeloid cells, also induced clonogenic growth in the presence of Pim2. In conclusion, Pim2 is an important target of Flt3-ITD-induced transformation, and overexpression of Pim2 together with Flt3-Wt or D835Y receptor mimics Flt3-ITD-mediated transformation. Pim2 complements with Flt3-Wt signaling to induce proliferation by enhancing G(1)/S-phase progression of the cell cycle.