RESUMEN
Shwachman-Diamond syndrome (SDS) is an inherited bone marrow failure disorder that often presents at infancy. Progress has been made in revealing causal mutated genes (SBDS and others), ribosome defects, and hematopoietic aberrations in SDS. However, the mechanism underlying the hematopoietic failure remained unknown, and treatment options are limited. Herein, we investigated the onset of SDS embryonic hematopoietic impairments. We generated SDS and control human-derived induced pluripotent stem cells (iPSCs). SDS iPSCs recapitulated the SDS hematological phenotype. Detailed stepwise evaluation of definitive hematopoiesis revealed defects that started at the early emerging hematopoietic progenitor (EHP) stage after mesoderm and hemogenic endothelium were normally induced. Hematopoietic potential of EHPs was markedly reduced, and the introduction of SBDS in SDS iPSCs improved colony formation. Transcriptome analysis revealed reduced expression of ribosome and oxidative phosphorylation-related genes in undifferentiated and differentiated iPSCs. However, certain pathways (e.g., DNA replication) and genes (e.g., CHCHD2) were exclusively or more severely dysregulated in EHPs compared with earlier and later stages. To our knowledge, this study offers for the first time an insight into the embryonic onset of human hematopoietic defects in an inherited bone marrow failure syndrome and reveals cellular and molecular aberrations at critical stages of hematopoietic development toward EHPs.
Asunto(s)
Diferenciación Celular , Hematopoyesis , Células Madre Hematopoyéticas , Células Madre Pluripotentes Inducidas , Síndrome de Shwachman-Diamond , Humanos , Células Madre Hematopoyéticas/metabolismo , Células Madre Hematopoyéticas/patología , Células Madre Pluripotentes Inducidas/metabolismo , Células Madre Pluripotentes Inducidas/citología , Perfilación de la Expresión Génica , Fenotipo , Mutación , Lipomatosis/genética , Lipomatosis/patología , Lipomatosis/metabolismo , Ribosomas/metabolismo , Ribosomas/genética , Biomarcadores , Transcriptoma , ProteínasRESUMEN
Increased fibrinolysis is an important component of acute promyelocytic leukemia (APL) bleeding diathesis. APL blasts overexpress annexin II (ANXII), a receptor for tissue plasminogen activator (tPA), and plasminogen, thereby increasing plasmin generation. Previous studies suggested that ANXII plays a pivotal role in APL coagulopathy. ANXII binding to tPA can be inhibited by homocysteine and hyperhomocysteinemia can be induced by L-methionine supplementation. In the present study, we used an APL mouse model to study ANXII function and the effects of hyperhomocysteinemia in vivo. Leukemic cells expressed higher ANXII and tPA plasma levels (11.95 ng/mL in leukemic vs 10.74 ng/mL in wild-type; P = .004). In leukemic mice, administration of L-methionine significantly increased homocysteine levels (49.0 µmol/mL and < 6.0 µmol/mL in the treated and nontreated groups, respectively) and reduced tPA levels to baseline concentrations. The latter were also decreased after infusion of the LCKLSL peptide, a competitor for the ANXII tPA-binding site (11.07 ng/mL; P = .001). We also expressed and purified the p36 component of ANXII in Pichia methanolica. The infusion of p36 in wild-type mice increased tPA and thrombin-antithrombin levels, and the latter was reversed by L-methionine administration. The results of the present study demonstrate the relevance of ANXII in vivo and suggest that methionine-induced hyperhomocysteinemia may reverse hyperfibrinolysis in APL.
Asunto(s)
Anexina A2/metabolismo , Fibrinólisis/fisiología , Hiperhomocisteinemia/inducido químicamente , Leucemia Promielocítica Aguda , Metionina/farmacología , Animales , Anexina A2/farmacología , Coagulación Sanguínea/fisiología , Trasplante de Médula Ósea , Modelos Animales de Enfermedad , Fibrinolisina/metabolismo , Homocisteína/sangre , Leucemia Promielocítica Aguda/complicaciones , Leucemia Promielocítica Aguda/metabolismo , Leucemia Promielocítica Aguda/patología , Ratones , Ratones Endogámicos C57BL , Ratones Transgénicos , Proteínas Recombinantes/metabolismo , Proteínas Recombinantes/farmacología , Activador de Tejido Plasminógeno/sangreAsunto(s)
Protocolos de Quimioterapia Combinada Antineoplásica/uso terapéutico , Predisposición Genética a la Enfermedad , Leucemia Mieloide Aguda/diagnóstico , Leucemia Mieloide Aguda/genética , Polimorfismo de Nucleótido Simple , Proteína p53 Supresora de Tumor/genética , Adulto , Anciano , Anciano de 80 o más Años , Alelos , Aberraciones Cromosómicas , Citarabina/uso terapéutico , Daunorrubicina/uso terapéutico , Etopósido/uso terapéutico , Femenino , Expresión Génica , Humanos , Idarrubicina/uso terapéutico , Leucemia Mieloide Aguda/tratamiento farmacológico , Leucemia Mieloide Aguda/mortalidad , Masculino , Persona de Mediana Edad , Pronóstico , Estudios Retrospectivos , Análisis de Supervivencia , Tioguanina/uso terapéuticoRESUMEN
Impairment of CCAAT Enhancer Binding Protein alpha (CEBPA) function is a common finding in acute myeloid leukemia; nevertheless, its relevance for acute promyelocytic leukemia pathogenesis is unclear. We analyzed the expression and assessed the methylation status of the core and upstream promoters of CEBPA in acute promyelocytic leukemia at diagnosis. Patients with acute promyelocytic leukemia (n = 18) presented lower levels of CEBPA expression compared to healthy controls (n = 5), but higher levels than those in acute myeloid leukemia with t(8;21) (n = 9) and with inv(16) (n = 5). Regarding the core promoter, we detected no methylation in 39 acute promyelocytic leukemia samples or in 8 samples from controls. In contrast, analysis of the upstream promoter showed methylation in 37 of 39 samples, with 17 patients showing methylation levels over 30%. Our results corroborate data obtained in animal models showing that CEBPA is down-regulated in acute promyelocytic leukemia stem cells and suggest that epigenetic mechanisms may be involved.
Asunto(s)
Proteína alfa Potenciadora de Unión a CCAAT/genética , Proteína alfa Potenciadora de Unión a CCAAT/metabolismo , Metilación de ADN/genética , Regulación hacia Abajo , Regulación Leucémica de la Expresión Génica , Leucemia Promielocítica Aguda , Regiones Promotoras Genéticas , Islas de CpG/genética , Epigenómica , Humanos , Leucemia Promielocítica Aguda/genética , Leucemia Promielocítica Aguda/fisiopatologíaAsunto(s)
Leucemia Mieloide Aguda/genética , Leucostasis/genética , Adolescente , Adulto , Anciano , Femenino , Duplicación de Gen , N-Metiltransferasa de Histona-Lisina , Humanos , Leucemia Mieloide Aguda/metabolismo , Leucemia Mieloide Aguda/patología , Leucostasis/metabolismo , Leucostasis/patología , Masculino , Persona de Mediana Edad , Mutación , Proteína de la Leucemia Mieloide-Linfoide/genética , Proteína de la Leucemia Mieloide-Linfoide/metabolismo , Proteínas Nucleares/genética , Proteínas Nucleares/metabolismo , Nucleofosmina , Estudios Retrospectivos , Adulto Joven , Tirosina Quinasa 3 Similar a fms/genética , Tirosina Quinasa 3 Similar a fms/metabolismoRESUMEN
BACKGROUND: Current results regarding treatment outcomes in acute myeloid leukemia (AML) point to significant differences between low- and middle-income countries (LMIC) and high-income countries (HIC). Excluding well-known socioeconomic issues, genetic markers important for prognosis have not been properly incorporated into the clinical practice so far and their usefulness outside of well-controlled clinical trials remain unknown. METHODS: Here, we assessed the clinical significance of the European LeukemiaNet (ELN) recommendations in 196 consecutive patients with AML in a real-life setting. All patients were younger than 60 years of age (49% male) and treated with conventional chemotherapy for induction and consolidation in three Brazilian Institutions that well represent Brazilian geographic and socioeconomic diversity. FINDINGS: Multivariable analysis showed that ELN recommendations had a slight association with complete remission achievement (odds ratio: 0.74, 95% confidence interval, CI: 0.53-1.01; P=0.06), but were independently associated with poor overall survival (OS) (hazard ratio, HR: 1.3, 95% CI: 1.1-1.54; P=0.002), disease-free survival (DFS) (HR: 1.42, 95% CI: 1.03-1.95; P=0.028) and event-free survival (EFS) (HR: 1.24, 95% CI: 1.06-1.47; P=0.007), considering initial leukocyte counts and age as confounders. ELN recommendations had no impact on cumulative incidence of relapse (P=0.09). INTERPRETATION: Our results suggest that within the context of LMIC, the prognostic markers recommended by ELN may be useful to predict patient's clinical outcomes; however, the OS, DFS and EFS were shorter than the reported in Europe and US for the respective risk groups.