RESUMEN
HOXA9 is commonly upregulated in acute myeloid leukemia (AML), in which it confers a poor prognosis. Characterizing the protein interactome of endogenous HOXA9 in human AML, we identified a chromatin complex of HOXA9 with the nuclear matrix attachment protein SAFB. SAFB perturbation phenocopied HOXA9 knockout to decrease AML proliferation, increase differentiation and apoptosis in vitro, and prolong survival in vivo. Integrated genomic, transcriptomic, and proteomic analyses further demonstrated that the HOXA9-SAFB (H9SB)-chromatin complex associates with nucleosome remodeling and histone deacetylase (NuRD) and HP1γ to repress the expression of factors associated with differentiation and apoptosis, including NOTCH1, CEBPδ, S100A8, and CDKN1A. Chemical or genetic perturbation of NuRD and HP1γ-associated catalytic activity also triggered differentiation, apoptosis, and the induction of these tumor-suppressive genes. Importantly, this mechanism is operative in other HOXA9-dependent AML genotypes. This mechanistic insight demonstrates the active HOXA9-dependent differentiation block as a potent mechanism of disease maintenance in AML that may be amenable to therapeutic intervention by targeting the H9SB interface and/or NuRD and HP1γ activity.
Asunto(s)
Leucemia Mieloide Aguda , Proteínas de Unión a la Región de Fijación a la Matriz , Humanos , Proteómica , Proteínas de Homeodominio/genética , Proteínas de Homeodominio/metabolismo , Leucemia Mieloide Aguda/tratamiento farmacológico , Factores de Transcripción/genética , Proteínas Asociadas a Matriz Nuclear , Cromatina , Receptores de Estrógenos/genética , Receptores de Estrógenos/uso terapéutico , Proteínas de Unión a la Región de Fijación a la Matriz/genéticaRESUMEN
Recurrent problems of patients with myelofibrosis (MF) are cytopenias, debiliating disease-related symptoms and splenomegaly. Whereas the latter are usually addressed by the JAK1/2 inhibitors ruxolitinib and fedratinib, cytopenias often remain critical. Momelotinib, a JAK1/2 inhibitor recently approved for the treatment of anemic MF patients, was shown to improve anemia via a direct inhibition of activin A receptor type I. In this German-wide, multicenter, retrospective analysis the safety and efficacy profile of momelotinib was evaluated in a real world setting within a cohort of 60 MF patients independent of pre-treatment. The median duration of treatment was 12 weeks. As a new, but manageable safety finding, creatinine increase (CTC°1-2) was detected in 10/60 patients (17%). Interestingly, not only hemoglobin levels increased in 84% of patients, but also platelet values (67%). In the cohort of transfusion-dependent individuals (n = 38), transfusion requirement improved in 15 patients (39%) with 8 reaching transfusion independency (21%). Transfusion independency was achieved within a median of 4 weeks (range 2-12). Spleen size decreased in 13/53 individuals (25%) with a median response time of 6 weeks. Thereof, 11 patients had been pre-treated with JAK inhibitor(s) (85%). Clinical improvement was detected in 24/51 symptomatic individuals (47%) with a median response time of 4 weeks. 5 patients stopped treatment due to side effects (8%), 6 patients due to a worsening of clinical symptoms (10%). Taken together, the MoReLife analysis identifies momelotinib as potent and safe therapeutic option also for heavily pre-treated cytopenic MF patients under real world conditions.
RESUMEN
The interaction of menin (MEN1) and MLL (MLL1, KMT2A) is a dependency and provides a potential opportunity for treatment of NPM1-mutant (NPM1mut) and MLL-rearranged (MLL-r) leukemias. Concomitant activating driver mutations in the gene encoding the tyrosine kinase FLT3 occur in both leukemias and are particularly common in the NPM1mut subtype. In this study, transcriptional profiling after pharmacological inhibition of the menin-MLL complex revealed specific changes in gene expression, with downregulation of the MEIS1 transcription factor and its transcriptional target gene FLT3 being the most pronounced. Combining menin-MLL inhibition with specific small-molecule kinase inhibitors of FLT3 phosphorylation resulted in a significantly superior reduction of phosphorylated FLT3 and transcriptional suppression of genes downstream of FLT3 signaling. The drug combination induced synergistic inhibition of proliferation, as well as enhanced apoptosis, compared with single-drug treatment in models of human and murine NPM1mut and MLL-r leukemias harboring an FLT3 mutation. Primary acute myeloid leukemia (AML) cells harvested from patients with NPM1mutFLT3mut AML showed significantly better responses to combined menin and FLT3 inhibition than to single-drug or vehicle control treatment, whereas AML cells with wild-type NPM1, MLL, and FLT3 were not affected by either of the 2 drugs. In vivo treatment of leukemic animals with MLL-r FLT3mut leukemia reduced leukemia burden significantly and prolonged survival compared with results in the single-drug and vehicle control groups. Our data suggest that combined menin-MLL and FLT3 inhibition represents a novel and promising therapeutic strategy for patients with NPM1mut or MLL-r leukemia and concurrent FLT3 mutation.
Asunto(s)
Protocolos de Quimioterapia Combinada Antineoplásica/uso terapéutico , Regulación Leucémica de la Expresión Génica/efectos de los fármacos , N-Metiltransferasa de Histona-Lisina/antagonistas & inhibidores , Leucemia Mieloide Aguda/tratamiento farmacológico , Proteína de la Leucemia Mieloide-Linfoide/antagonistas & inhibidores , Proteínas de Neoplasias/antagonistas & inhibidores , Inhibidores de Proteínas Quinasas/uso terapéutico , Proteínas Proto-Oncogénicas/antagonistas & inhibidores , Tirosina Quinasa 3 Similar a fms/antagonistas & inhibidores , Animales , Protocolos de Quimioterapia Combinada Antineoplásica/farmacología , Apoptosis/efectos de los fármacos , Línea Celular Tumoral , Técnicas de Cocultivo , Sinergismo Farmacológico , Humanos , Leucemia Mieloide Aguda/genética , Ratones , Ratones Endogámicos NOD , Proteína 1 del Sitio de Integración Viral Ecotrópica Mieloide/biosíntesis , Proteína 1 del Sitio de Integración Viral Ecotrópica Mieloide/genética , Proteínas de Neoplasias/biosíntesis , Proteínas de Neoplasias/genética , Proteínas Nucleares/genética , Nucleofosmina , Fosforilación , Inhibidores de Proteínas Quinasas/farmacología , Procesamiento Proteico-Postraduccional , Distribución Aleatoria , Transcripción Genética/efectos de los fármacos , Tirosina Quinasa 3 Similar a fms/biosíntesis , Tirosina Quinasa 3 Similar a fms/genéticaRESUMEN
PURPOSE OF REVIEW: Comprehensive sequencing studies aimed at determining the genetic landscape of myeloid neoplasms have identified epigenetic regulators to be among the most commonly mutated genes. Detailed studies have also revealed a number of epigenetic vulnerabilities. The purpose of this review is to outline these vulnerabilities and to discuss the new generation of drugs that exploit them. RECENT FINDINGS: In addition to deoxyribonucleic acid-methylation, novel epigenetic dependencies have recently been discovered in various myeloid neoplasms and many of them can be targeted pharmacologically. These include not only chromatin writers, readers, and erasers but also chromatin movers that shift nucleosomes to allow access for transcription. Inhibitors of protein-protein interactions represent a novel promising class of drugs that allow disassembly of oncogenic multiprotein complexes. SUMMARY: An improved understanding of disease-specific epigenetic vulnerabilities has led to the development of second-generation mechanism-based epigenetic drugs against myeloid neoplasms. Many of these drugs have been introduced into clinical trials and synergistic drug combination regimens have been shown to enhance efficacy and potentially prevent drug resistance.
Asunto(s)
Protocolos de Quimioterapia Combinada Antineoplásica/uso terapéutico , Epigénesis Genética/efectos de los fármacos , Regulación Neoplásica de la Expresión Génica/efectos de los fármacos , Neoplasias Hematológicas , Trastornos Mieloproliferativos , Transcripción Genética/efectos de los fármacos , Neoplasias Hematológicas/tratamiento farmacológico , Neoplasias Hematológicas/genética , Neoplasias Hematológicas/metabolismo , Humanos , Trastornos Mieloproliferativos/tratamiento farmacológico , Trastornos Mieloproliferativos/genética , Trastornos Mieloproliferativos/metabolismo , Nucleosomas/genética , Nucleosomas/metabolismoRESUMEN
Cohesin complex disruption alters gene expression, and cohesin mutations are common in myeloid neoplasia, suggesting a critical role in hematopoiesis. Here, we explore cohesin dynamics and regulation of hematopoietic stem cell homeostasis and differentiation. Cohesin binding increases at active regulatory elements only during erythroid differentiation. Prior binding of the repressive Ets transcription factor Etv6 predicts cohesin binding at these elements and Etv6 interacts with cohesin at chromatin. Depletion of cohesin severely impairs erythroid differentiation, particularly at Etv6-prebound loci, but augments self-renewal programs. Together with corroborative findings in acute myeloid leukemia and myelodysplastic syndrome patient samples, these data suggest cohesin-mediated alleviation of Etv6 repression is required for dynamic expression at critical erythroid genes during differentiation and how this may be perturbed in myeloid malignancies.
Asunto(s)
Proteínas de Ciclo Celular/genética , Proteínas de Ciclo Celular/metabolismo , Proteínas Cromosómicas no Histona/genética , Proteínas Cromosómicas no Histona/metabolismo , Regulación Leucémica de la Expresión Génica , Mutación , Trastornos Mieloproliferativos/genética , Trastornos Mieloproliferativos/metabolismo , Biomarcadores de Tumor , Línea Celular Tumoral , Femenino , Dosificación de Gen , Células Madre Hematopoyéticas/metabolismo , Células Madre Hematopoyéticas/patología , Histonas/metabolismo , Humanos , Masculino , Trastornos Mieloproliferativos/diagnóstico , Clasificación del Tumor , Unión Proteica , Proteínas Proto-Oncogénicas c-ets/metabolismo , Secuencias Reguladoras de Ácidos Nucleicos , Proteínas Represoras/metabolismo , Cohesinas , Proteína ETS de Variante de Translocación 6RESUMEN
Neural cell adhesion molecule 1 (NCAM1; CD56) is expressed in up to 20% of acute myeloid leukemia (AML) patients. NCAM1 is widely used as a marker of minimal residual disease; however, the biological function of NCAM1 in AML remains elusive. In this study, we investigated the impact of NCAM1 expression on leukemogenesis, drug resistance, and its role as a biomarker to guide therapy. Beside t(8;21) leukemia, NCAM1 expression was found in most molecular AML subgroups at highly heterogeneous expression levels. Using complementary genetic strategies, we demonstrated an essential role of NCAM1 in the regulation of cell survival and stress resistance. Perturbation of NCAM1 induced cell death or differentiation and sensitized leukemic blasts toward genotoxic agents in vitro and in vivo. Furthermore, Ncam1 was highly expressed in leukemic progenitor cells in a murine leukemia model, and genetic depletion of Ncam1 prolonged disease latency and significantly reduced leukemia-initiating cells upon serial transplantation. To further analyze the mechanism of the NCAM1-associated phenotype, we performed phosphoproteomics and transcriptomics in different AML cell lines. NCAM1 expression strongly associated with constitutive activation of the MAPK-signaling pathway, regulation of apoptosis, or glycolysis. Pharmacological inhibition of MEK1/2 specifically inhibited proliferation and sensitized NCAM1+ AML cells to chemotherapy. In summary, our data demonstrate that aberrant expression of NCAM1 is involved in the maintenance of leukemic stem cells and confers stress resistance, likely due to activation of the MAPK pathway. Targeting MEK1/2 sensitizes AML blasts to genotoxic agents, indicating a role for NCAM1 as a biomarker to guide AML treatment.
Asunto(s)
Biomarcadores de Tumor/metabolismo , Crisis Blástica/metabolismo , Antígeno CD56/metabolismo , Resistencia a Antineoplásicos , Leucemia Mieloide Aguda/metabolismo , Proteínas de Neoplasias/metabolismo , Animales , Apoptosis/genética , Biomarcadores de Tumor/genética , Crisis Blástica/genética , Crisis Blástica/patología , Crisis Blástica/terapia , Antígeno CD56/genética , Femenino , Glucólisis/genética , Células HL-60 , Humanos , Células K562 , Leucemia Mieloide Aguda/genética , Leucemia Mieloide Aguda/patología , Leucemia Mieloide Aguda/terapia , Sistema de Señalización de MAP Quinasas/genética , Masculino , Ratones , Ratones Endogámicos NOD , Ratones Noqueados , Proteínas de Neoplasias/genéticaRESUMEN
FLT3 internal tandem duplication (FLT3ITD) mutations are common in acute myeloid leukemia (AML) associated with poor patient prognosis. Although new-generation FLT3 tyrosine kinase inhibitors (TKI) have shown promising results, the outcome of FLT3ITD AML patients remains poor and demands the identification of novel, specific, and validated therapeutic targets for this highly aggressive AML subtype. Utilizing an unbiased genome-wide clustered regularly interspaced short palindromic repeats (CRISPR)/Cas9 screen, we identify GLS, the first enzyme in glutamine metabolism, as synthetically lethal with FLT3-TKI treatment. Using complementary metabolomic and gene-expression analysis, we demonstrate that glutamine metabolism, through its ability to support both mitochondrial function and cellular redox metabolism, becomes a metabolic dependency of FLT3ITD AML, specifically unmasked by FLT3-TKI treatment. We extend these findings to AML subtypes driven by other tyrosine kinase (TK) activating mutations and validate the role of GLS as a clinically actionable therapeutic target in both primary AML and in vivo models. Our work highlights the role of metabolic adaptations as a resistance mechanism to several TKI and suggests glutaminolysis as a therapeutically targetable vulnerability when combined with specific TKI in FLT3ITD and other TK activating mutation-driven leukemias.
Asunto(s)
Glutamina/metabolismo , Leucemia Mieloide Aguda , Mutación , Inhibidores de Proteínas Quinasas/farmacología , Tirosina Quinasa 3 Similar a fms , Sistemas CRISPR-Cas , Activación Enzimática/efectos de los fármacos , Activación Enzimática/genética , Estudio de Asociación del Genoma Completo , Glutamina/genética , Humanos , Células K562 , Leucemia Mieloide Aguda/tratamiento farmacológico , Leucemia Mieloide Aguda/enzimología , Leucemia Mieloide Aguda/genética , Células THP-1 , Tirosina Quinasa 3 Similar a fms/antagonistas & inhibidores , Tirosina Quinasa 3 Similar a fms/genética , Tirosina Quinasa 3 Similar a fms/metabolismoRESUMEN
Activating KRAS mutations are detected in a substantial number of hematologic malignancies. In a murine T-cell acute lymphoblastic leukemia (T-ALL) model, we previously showed that expression of oncogenic Kras induced a premalignant state accompanied with an arrest in T-cell differentiation and acquisition of somatic Notch1 mutations. These findings prompted us to investigate whether the expression of oncogenic KRAS directly affects DNA damage repair. Applying divergent, but complementary, genetic approaches, we demonstrate that the expression of KRAS mutants is associated with increased expression of DNA ligase 3α, poly(ADP-ribose) polymerase 1 (PARP1), and X-ray repair cross-complementing protein 1 (XRCC1), all essential components of the error-prone, alternative nonhomologous end-joining (alt-NHEJ) pathway. Functional studies revealed delayed repair kinetics, increased misrepair of DNA double-strand breaks, and the preferential use of microhomologous DNA sequences for end joining. Similar effects were observed in primary murine T-ALL blasts. We further show that KRAS-mutated cells, but not KRAS wild-type cells, rely on the alt-NHEJ repair pathway on genotoxic stress. RNA interference-mediated knockdown of DNA ligase 3α abolished resistance to apoptotic cell death in KRAS-mutated cells. Our data indicate that targeting components of the alt-NHEJ pathway sensitizes KRAS-mutated leukemic cells to standard chemotherapeutics and represents a promising approach for inducing synthetic lethal vulnerability in cells harboring otherwise nondruggable KRAS mutations.
Asunto(s)
Antineoplásicos/farmacología , Reparación del ADN/genética , Mutación , Leucemia-Linfoma Linfoblástico de Células T Precursoras/genética , Proteínas Proto-Oncogénicas p21(ras)/genética , Animales , Apoptosis/efectos de los fármacos , Apoptosis/genética , Ensayo Cometa , Roturas del ADN de Doble Cadena , Reparación del ADN/efectos de los fármacos , Modelos Animales de Enfermedad , Humanos , Inmunohistoquímica , Ratones , Ratones Endogámicos C57BL , Ratones Transgénicos , Leucemia-Linfoma Linfoblástico de Células T Precursoras/tratamiento farmacológico , Leucemia-Linfoma Linfoblástico de Células T Precursoras/patología , Transducción GenéticaRESUMEN
SIRT1 is an important regulator of cellular stress response and genomic integrity. Its role in tumorigenesis is controversial. Whereas sirtuin 1 (SIRT1) can act as a tumor suppressor in some solid tumors, increased expression has been demonstrated in many cancers, including hematologic malignancies. In chronic myeloid leukemia, SIRT1 promoted leukemia development, and targeting SIRT1 sensitized chronic myeloid leukemia progenitors to tyrosine kinase inhibitor treatment. In this study, we investigated the role of SIRT1 in acute myeloid leukemia (AML). We show that SIRT1 protein, but not RNA levels, is overexpressed in AML samples harboring activating mutations in signaling pathways. In FMS-like tyrosine kinase 3-internal tandem duplication (FLT3-ITD)(+)-cells protein, expression of SIRT1 is regulated by FLT3 kinase activity. In addition, SIRT1 function is modulated via the ATM-DBC1-SIRT1 axis in a FLT3-ITD-dependent manner. In murine leukemia models driven by MLL-AF9 or AML1-ETO coexpressing FLT3-ITD, SIRT1 acts as a safeguard to counteract oncogene-induced stress, and leukemic blasts become dependent on SIRT1 activity. Pharmacologic targeting or RNAi-mediated knockdown of SIRT1 inhibited cell growth and sensitized AML cells to tyrosine kinase inhibitor treatment and chemotherapy. This effect was a result of the restoration of p53 activity. Our data suggest that targeting SIRT1 represents an attractive therapeutic strategy to overcome primary resistance in defined subsets of patients with AML.
Asunto(s)
Daño del ADN/fisiología , Leucemia Mieloide Aguda/genética , Leucemia Mieloide Aguda/metabolismo , Sirtuina 1/metabolismo , Proteína p53 Supresora de Tumor/metabolismo , Animales , Activación Enzimática/fisiología , Técnicas de Sustitución del Gen , Técnicas de Silenciamiento del Gen , Xenoinjertos , Humanos , Ratones , Ratones Endogámicos C57BL , Transducción de Señal/fisiología , Sirtuina 1/genéticaRESUMEN
Recent exome-wide studies discovered frequent somatic mutations in the epigenetic modifier ZNF217 in primary mediastinal B cell lymphoma (PMBCL) and related disorders. As functional consequences of ZNF217 alterations remain unknown, we comprehensively evaluated their impact in PMBCL. Targeted sequencing identified genetic lesions affecting ZNF217 in 33% of 157 PMBCL patients. Subsequent gene expression profiling (n = 120) revealed changes in cytokine and interferon signal transduction in ZNF217-aberrant PMBCL cases. In vitro, knockout of ZNF217 led to changes in chromatin accessibility interfering with binding motifs for crucial lymphoma-associated transcription factors. This led to disturbed expression of interferon-responsive and inflammation-associated genes, altered cell behavior, and aberrant differentiation. Mass spectrometry demonstrates that ZNF217 acts within a histone modifier complex containing LSD1, CoREST and HDAC and interferes with H3K4 methylation and H3K27 acetylation. Concluding, our data suggest non-catalytic activity of ZNF217, which directs histone modifier complex function and controls B cell differentiation-associated patterns of chromatin structure.
Asunto(s)
Histonas , Linfoma de Células B , Humanos , Histonas/metabolismo , Transactivadores/metabolismo , Interferones/genética , Línea Celular Tumoral , Mutación , Transducción de Señal/genética , Cromatina/genética , Linfoma de Células B/genéticaRESUMEN
BACKGROUND: Long-term hematopoietic stem cells (LT-HSCs) reside in bone marrow niches with tightly controlled reactive oxygen species (ROS) levels. ROS increase results into LT-HSC differentiation and stem cell exhaustion. Paraoxonase 2 (PON2) has been shown to be important for ROS control. OBJECTIVES: We investigate the effects of inactivation of the PON2 gene on hematopoietic cell differentiation and activity. METHODS AND RESULTS: In young mice with inactivated Pon2 gene (Pon2 -/-, <3 months), we observed an increase of LT-HSCs and a reduced frequency of progenitor cells. In competitive transplantations, young Pon2-/- BM outcompeted WT BM at early time points. ROS levels were significantly increased in Pon2-/- whole BM, but not in Pon2-/- LT-HSCs. In more differentiated stages of hematopoiesis, Pon2 deficiency led to a misbalanced erythropoiesis both in physiologic and stress conditions. In older mice (>9 months), Pon2 depletion caused an increase in LT-HSCs as well as increased levels of granulocyte/macrophage progenitors (GMPs) and myeloid skewing, indicating a premature aging phenotype. No significant changes in ROS levels in old Pon2-/- LT- and short-term (ST-) HSCs were observed, but a significant reduction of spontaneous apoptotic cell death was measured. RNA-seq analysis in Pon2 -/- LT-HSCs identified overrepresentation of genes involved in the C-X-C chemokine receptor type 4 (Cxcr4) signaling, suggesting compensatory mechanisms to overcome ROS-mediated accelerated aging in hematopoietic progenitor cells. CONCLUSIONS: In summary, our current data indicate that PON2 is involved in the regulation of HSC functions.
Asunto(s)
Antioxidantes/metabolismo , Arildialquilfosfatasa/deficiencia , Eritropoyesis/fisiología , Células Madre Hematopoyéticas/metabolismo , Animales , Arildialquilfosfatasa/metabolismo , Diferenciación Celular/fisiología , Línea Celular , Células Madre Hematopoyéticas/enzimología , Ratones , Fenotipo , Especies Reactivas de Oxígeno/metabolismoRESUMEN
Altered transcription is a cardinal feature of acute myeloid leukemia (AML); however, exactly how mutations synergize to remodel the epigenetic landscape and rewire three-dimensional DNA topology is unknown. Here, we apply an integrated genomic approach to a murine allelic series that models the two most common mutations in AML: Flt3-ITD and Npm1c. We then deconvolute the contribution of each mutation to alterations of the epigenetic landscape and genome organization, and infer how mutations synergize in the induction of AML. Our studies demonstrate that Flt3-ITD signals to chromatin to alter the epigenetic environment and synergizes with mutations in Npm1c to alter gene expression and drive leukemia induction. These analyses also allow the identification of long-range cis-regulatory circuits, including a previously unknown superenhancer of Hoxa locus, as well as larger and more detailed gene-regulatory networks, driven by transcription factors including PU.1 and IRF8, whose importance we demonstrate through perturbation of network members.
Asunto(s)
Ensamble y Desensamble de Cromatina/genética , ADN de Neoplasias/química , Regulación Leucémica de la Expresión Génica , Histonas/metabolismo , Leucemia Mieloide Aguda/genética , Mutación/genética , Procesamiento Proteico-Postraduccional , Animales , Secuencia de Bases , Modelos Animales de Enfermedad , Elementos de Facilitación Genéticos/genética , Redes Reguladoras de Genes , Sitios Genéticos , Humanos , Ratones Endogámicos C57BL , Proteínas Nucleares/metabolismo , Nucleofosmina , Análisis de Componente Principal , ARN Mensajero/genética , ARN Mensajero/metabolismo , Transcripción Genética , Tirosina Quinasa 3 Similar a fms/metabolismoRESUMEN
Epigenetic regulators, such as EZH2, are frequently mutated in cancer, and loss-of-function EZH2 mutations are common in myeloid malignancies. We have examined the importance of cellular context for Ezh2 loss during the evolution of acute myeloid leukemia (AML), where we observed stage-specific and diametrically opposite functions for Ezh2 at the early and late stages of disease. During disease maintenance, WT Ezh2 exerts an oncogenic function that may be therapeutically targeted. In contrast, Ezh2 acts as a tumor suppressor during AML induction. Transcriptional analysis explains this apparent paradox, demonstrating that loss of Ezh2 derepresses different expression programs during disease induction and maintenance. During disease induction, Ezh2 loss derepresses a subset of bivalent promoters that resolve toward gene activation, inducing a feto-oncogenic program that includes genes such as Plag1, whose overexpression phenocopies Ezh2 loss to accelerate AML induction in mouse models. Our data highlight the importance of cellular context and disease phase for the function of Ezh2 and its potential therapeutic implications.
Asunto(s)
Progresión de la Enfermedad , Proteína Potenciadora del Homólogo Zeste 2/genética , Leucemia Mieloide Aguda/genética , Leucemia Mieloide Aguda/mortalidad , Mutación con Pérdida de Función , Animales , Células de la Médula Ósea/metabolismo , Trasplante de Médula Ósea , Línea Celular Tumoral , Estudios de Cohortes , Modelos Animales de Enfermedad , Frecuencia de los Genes , Histonas/metabolismo , Humanos , Leucemia Mieloide Aguda/sangre , Leucemia Mieloide Aguda/patología , Ratones , Ratones Endogámicos C57BL , Pronóstico , Tasa de Supervivencia , Transducción Genética , Trasplante HomólogoRESUMEN
Loss-of-function mutations of cyclic-AMP response element binding protein, binding protein (CREBBP) are prevalent in lymphoid malignancies. However, the tumour suppressor functions of CREBBP remain unclear. We demonstrate that loss of Crebbp in murine haematopoietic stem and progenitor cells (HSPCs) leads to increased development of B-cell lymphomas. This is preceded by accumulation of hyperproliferative lymphoid progenitors with a defective DNA damage response (DDR) due to a failure to acetylate p53. We identify a premalignant lymphoma stem cell population with decreased H3K27ac, which undergoes transcriptional and genetic evolution due to the altered DDR, resulting in lymphomagenesis. Importantly, when Crebbp is lost later in lymphopoiesis, cellular abnormalities are lost and tumour generation is attenuated. We also document that CREBBP mutations may occur in HSPCs from patients with CREBBP-mutated lymphoma. These data suggest that earlier loss of Crebbp is advantageous for lymphoid transformation and inform the cellular origins and subsequent evolution of lymphoid malignancies.
Asunto(s)
Proteína de Unión a CREB/deficiencia , Proteína de Unión a CREB/metabolismo , Transformación Celular Neoplásica/metabolismo , Células Progenitoras Linfoides/metabolismo , Linfoma/metabolismo , Células Madre Neoplásicas/metabolismo , Acetilación , Animales , Proteína de Unión a CREB/genética , Proliferación Celular , Autorrenovación de las Células , Transformación Celular Neoplásica/genética , Transformación Celular Neoplásica/patología , Células Cultivadas , Daño del ADN , Epigénesis Genética , Regulación Neoplásica de la Expresión Génica , Predisposición Genética a la Enfermedad , Histonas/metabolismo , Linfangiogénesis , Células Progenitoras Linfoides/patología , Linfoma/genética , Linfoma/patología , Linfopoyesis , Metilación , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Mutación , Células Madre Neoplásicas/patología , Fenotipo , Transducción de Señal , Factores de Tiempo , Transcripción Genética , Proteína p53 Supresora de Tumor/genética , Proteína p53 Supresora de Tumor/metabolismoRESUMEN
Triggering receptor expressed on myeloid cells 1 (TREM-1) is an important mediator of innate inflammatory responses in microbial infections and sepsis. TREM-1 ligation on neutrophils (PMN) or monocytes results in the production of proinflammatory cytokines. Engagement of TREM-1 induces the activation of MAP kinases as well as rapid Ca(2+) mobilization. However, a detailed understanding of TREM-1 signaling pathways is currently lacking. We evaluated the TREM-1 signaling hierarchy in monocytic cells and found that the acute myeloid leukemia cell line MUTZ-3 expresses TREM-1 in a natural and functional manner. We compared essential signaling molecules of the TREM-1, TLR and NLR cascade in MUTZ-3 cells as well as primary monocytes or PMN by Western blot analysis. These studies confirmed the essential role of phosphatidyl inositide 3-kinase (PI3K) and p38MAPK in the TREM-1 as well as the TLR or NLR cascade of monocytic cells. Importantly, PI3K and p38MAPK signals in monocytic cells both control Ca(2+) mobilization and are directly connected in the TREM-1 signaling hierarchy, which contrasts previous results obtained in PMN. Taken together, our results indicate cell type-specific differences in the TREM-1 signaling cascade and contribute to an enhanced understanding of the regulation of innate inflammatory responses.
Asunto(s)
Señalización del Calcio , Leucemia Mieloide Aguda/inmunología , Glicoproteínas de Membrana/metabolismo , Monocitos/inmunología , Neutrófilos/inmunología , Receptores Inmunológicos/metabolismo , Línea Celular Tumoral , Citocinas/metabolismo , Quinasas MAP Reguladas por Señal Extracelular/metabolismo , Humanos , Inmunidad Innata , Mediadores de Inflamación/metabolismo , Especificidad de Órganos , Fosfatidilinositol 3-Quinasas/metabolismo , Receptores Toll-Like/metabolismo , Receptor Activador Expresado en Células Mieloides 1 , Proteínas Quinasas p38 Activadas por Mitógenos/metabolismoRESUMEN
MOZ-TIF2 is a leukemogenic fusion oncoprotein that confers self-renewal capability to hematopoietic progenitor cells and induces acute myelogenous leukemia (AML) with long latency in bone marrow transplantation assays. Here, we report that FLT3-ITD transforms hematopoietic cells in cooperation with MOZ-TIF2 in vitro and in vivo. Coexpression of FLT3-ITD confers growth factor independent survival/proliferation, shortens disease latency, and results in an increase in the number of leukemic stem cells (LSC). We show that STAT5, a major effector of aberrant FLT3-ITD signal transduction, is both necessary and sufficient for this cooperative effect. In addition, STAT5 signaling is essential for MOZ-TIF2-induced leukemic transformation itself. Lack of STAT5 in fetal liver cells caused rapid differentiation and loss of replating capacity of MOZ-TIF2-transduced cells enriched for LSCs. Furthermore, mice serially transplanted with Stat5(-/-) MOZ-TIF2 leukemic cells develop AML with longer disease latency and finally incomplete penetrance when compared with mice transplanted with Stat5(+/+) MOZ-TIF2 leukemic cells. These data suggest that STAT5AB is required for the self-renewal of LSCs and represents a combined signaling node of FLT3-ITD and MOZ-TIF2 driven leukemogenesis. Therefore, targeting aberrantly activated STAT5 or rewired downstream signaling pathways may be a promising therapeutic option.