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MOZ and MLL encoding a histone acetyltransferase and a histone methyltransferase, respectively, are targets for recurrent chromosomal translocations found in acute myeloblastic or lymphoblastic leukemia. We have previously shown that MOZ and MLL cooperate to activate HOXA9 gene expression in hematopoietic stem/progenitors cells. To dissect the mechanism of action of this complex, we decided to identify new proteins interacting with MOZ. We found that the scaffold protein Symplekin that supports the assembly of polyadenylation machinery was identified by mass spectrometry. Symplekin interacts and co-localizes with both MOZ and MLL in immature hematopoietic cells. Its inhibition leads to a decrease of the HOXA9 protein level but not of Hoxa9 mRNA and to an over-recruitment of MOZ and MLL onto the HOXA9 promoter. Altogether, our results highlight the role of Symplekin in transcription repression involving a regulatory network between MOZ, MLL and Symplekin.
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Sistema Hematopoyético/citología , Histona Acetiltransferasas/metabolismo , Proteínas de Homeodominio/metabolismo , Proteína de la Leucemia Mieloide-Linfoide/metabolismo , Proteínas Nucleares/metabolismo , Factores de Escisión y Poliadenilación de ARNm/metabolismo , Línea Celular , N-Metiltransferasa de Histona-Lisina , Proteínas de Homeodominio/genética , Humanos , Poliadenilación , Regiones Promotoras Genéticas/genética , Unión Proteica , Transporte de Proteínas , ARN Mensajero/genética , ARN Mensajero/metabolismoRESUMEN
PURPOSE: Acute myeloid leukemia (AML) is a refractory hematologic malignancy that poses a serious threat to human health. Exploring alternative therapeutic strategies capable of inducing alternative modes of cell death, such as ferroptosis, holds great promise as a viable and effective intervention. METHODS: We analyzed online database data and collected clinical samples to verify the expression and function of BMAL1 in AML. We conducted experiments on AML cell proliferation, cell cycle, ferroptosis, and chemotherapy resistance by overexpressing/knocking down BMAL1 and using assays such as MDA detection and BODIPY 581/591 C11 staining. We validated the transcriptional regulation of HMGB1 by BMAL1 through ChIP assay, luciferase assay, RNA level detection, and western blotting. Finally, we confirmed the results of our cell experiments at the animal level. RESULTS: BMAL1 up-regulation is an observed phenomenon in AML patients. Furthermore, there existed a strong correlation between elevated levels of BMAL1 expression and inferior prognosis in individuals with AML. We found that knocking down BMAL1 inhibited AML cell growth by blocking the cell cycle. Conversely, overexpressing BMAL1 promoted AML cell proliferation. Moreover, our research results revealed that BMAL1 inhibited ferroptosis in AML cells through BMAL1-HMGB1-GPX4 pathway. Finally, knocking down BMAL1 can enhance the efficacy of certain first-line cancer therapeutic drugs, including venetoclax, dasatinib, and sorafenib. CONCLUSION: Our research results suggest that BMAL1 plays a crucial regulatory role in AML cell proliferation, drug resistance, and ferroptosis. BMAL1 could be a potential important therapeutic target for AML.
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Factores de Transcripción ARNTL , Resistencia a Antineoplásicos , Ferroptosis , Proteína HMGB1 , Leucemia Mieloide Aguda , Fosfolípido Hidroperóxido Glutatión Peroxidasa , Transducción de Señal , Animales , Femenino , Humanos , Masculino , Ratones , Factores de Transcripción ARNTL/genética , Factores de Transcripción ARNTL/metabolismo , Línea Celular Tumoral , Proliferación Celular/efectos de los fármacos , Ferroptosis/efectos de los fármacos , Proteína HMGB1/metabolismo , Proteína HMGB1/genética , Leucemia Mieloide Aguda/tratamiento farmacológico , Leucemia Mieloide Aguda/metabolismo , Leucemia Mieloide Aguda/patología , Leucemia Mieloide Aguda/genética , Ratones Desnudos , Fosfolípido Hidroperóxido Glutatión Peroxidasa/metabolismo , Fosfolípido Hidroperóxido Glutatión Peroxidasa/genética , Pronóstico , Sulfonamidas/farmacología , Ensayos Antitumor por Modelo de XenoinjertoRESUMEN
TP53-mutated myelodysplastic syndrome (MDS) and acute myeloid leukemia (AML) form a distinct and heterogeneous group of myeloid malignancies associated with poor outcomes. Studies carried out in the last years have in part elucidated the complex role played by TP53 mutations in the pathogenesis of these myeloid disorders and in the mechanisms of drug resistance. A consistent number of studies has shown that some molecular parameters, such as the presence of a single or multiple TP53 mutations, the presence of concomitant TP53 deletions, the association with co-occurring mutations, the clonal size of TP53 mutations, the involvement of a single (monoallelic) or of both TP53 alleles (biallelic) and the cytogenetic architecture of concomitant chromosome abnormalities are major determinants of outcomes of patients. The limited response of these patients to standard treatments, including induction chemotherapy, hypomethylating agents and venetoclax-based therapies and the discovery of an immune dysregulation have induced a shift to new emerging therapies, some of which being associated with promising efficacy. The main aim of these novel immune and nonimmune strategies consists in improving survival and in increasing the number of TP53-mutated MDS/AML patients in remission amenable to allogeneic stem cell transplantation.
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The following fictional case is intended as a learning tool within the Pathology Competencies for Medical Education (PCME), a set of national standards for teaching pathology. These are divided into three basic competencies: Disease Mechanisms and Processes, Organ System Pathology, and Diagnostic Medicine and Therapeutic Pathology. For additional information, and a full list of learning objectives for all three competencies, see http://journals.sagepub.com/doi/10.1177/2374289517715040.1.
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Increased DNA damage and alteration of the DNA damage response (DDR) are critical features of genetic instability presumably implicated in pathogenesis of myelodysplastic syndromes (MDS) and acute myeloid leukemias (AML). We used immunofluorescence staining of γH2AX and 53BP1 for analyzing DNA double-strand breaks (DSB) in MDS and AML cell lines, in CD34+ selected cells of normal and MDS bone marrow (including three cases of chronic myelomonocytic leukemias) and in blasts of AML bone marrow. In addition, we screened for activation of the DDR by immunoblotting of p-ATM, p-ATR, p-CHK1, p-CHK2 and p-TP53. As compared to γH2AX foci levels in normal bone marrow samples (0.2 focus per CD34+ cell±0.0; mean±standard error of mean), increased levels of γH2AX foci were detected in 16/16 MDS bone marrow samples (2.8 foci per CD34+ cell±0.5), 18/18 AML bone marrow samples (5.5 foci per blast±0.5), 1/1 MDS cell line (6.4 foci per cell) and 6/6 AML cell lines (12.0 foci per cell±0.6). γH2AX and 53BP1 co-localized in all tested samples forming diffuse, clustered and marginal patterns. Further, DDR proteins were expressed heterogeneously suggesting impairment of the DDR. In summary, our results provide evidence for a continuous increase of DSB across the spectrum from MDS to AML in conjunction with an impaired DDR. Co-localization of γH2AX and 53BP1 indicates promotion of (in)effective nonhomologous end-joining repair mechanisms at sites of DSB. Moreover, γH2AX/53BP1 foci distribution presumably reveals a non-random spatial organization of the genome in MDS and AML.
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Daño del ADN , Reparación del ADN , Leucemia Mieloide Aguda/genética , Síndromes Mielodisplásicos/genética , Médula Ósea , Línea Celular Tumoral , Roturas del ADN de Doble Cadena , Histonas/metabolismo , Humanos , Proteína 1 de Unión al Supresor Tumoral P53/metabolismoRESUMEN
The role of bone marrow dysplastic erythroid precursors (EP) in both MDS and AML has been the subject of considerable debate over the past several decades. We have analyzed a large series of adults with MDS and focused on whether any% of EP identified in the bone marrow aspirates of over 1400 patients selected from the Dusseldorf, Germany adult MDS Registry has prognostic relevance. The data was examined for varying% of blasts, the WHO prognostic MDS subtypes and the IPSS-R. We did not identify any adjustment of bone marrow blast percentage by%EP, incuding the 50% rule" developed by the FAB leukemia working group, to have a meaningful impact on outcome, either leukemic risk of progression or overall survival. There was a trend for a%EP<15% to actually have a worse survival than any other EP subset. We can no longer recommend the application of the "50% rule" in the calculation of the% of myeloblasts in bone marrow aspirates.
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Células Precursoras Eritroides/patología , Leucemia Mieloide Aguda/patología , Síndromes Mielodisplásicos/patología , Adulto , Crisis Blástica/patología , Médula Ósea/patología , Recuento de Células , Progresión de la Enfermedad , Humanos , Guías de Práctica Clínica como Asunto , Pronóstico , Sistema de Registros , Estudios Retrospectivos , Tasa de Supervivencia , Adulto JovenRESUMEN
Introducción: En el Instituto de Hematología e Inmunología se realiza el estudio molecular de las leucemias mieloides agudas (LMA). Para las leucemias mieloides agudas no promielocíticas (LPM) se determinan cuatro biomarcadores: los genes de fusión RUNX1-RUNX1T1 y CBF(-MYH11, la duplicación interna en tándem del gen FLT3 (DIT FLT3) y la mutación A del gen NPM1 (NPM1-A). Objetivo: Determinar la frecuencia de estos cuatro biomarcadores, en pacientes cubanos con leucemias mieloides agudas primaria no promielocíticas. Métodos: Se incluyeron 91 pacientes entre niños y adultos, estudiados en el Instituto durante tres años desde el debut. A partir de ARN de sangre medular se obtuvo ADN complementario por transcripción inversa; se amplificaron los fragmentos correspondientes mediante la reacción en cadena de la polimerasa y el producto se analizó por electroforesis capilar. Resultados: El RUNX1-RUNX1T1 apareció en el 24,2 por ciento, fue más frecuente en los pacientes pediátricos y disminuyó significativamente con la edad. El CBFβ-MYH11 solo se encontró en adultos (4,8 por ciento). La NPM1-A con 41 por ciento fue mayoritaria entre los adultos. La DIT FLT3 se observó en el 21,6 por ciento y no mostró relación con la edad. NPM1-A y DIT FLT3 fueron las aberraciones con mayor presencia simultánea. Conclusiones: Por primera vez se describe la frecuencia de los cuatro biomarcadores moleculares en los pacientes cubanos con leucemias mieloides agudas primaria no promielocíticas; su comportamiento fue similar a lo descrito por otros autores, aunque se encontraron algunas particularidades(AU)
Introduction: At the Institute of Hematology and Immunology, the molecular study of acute myeloid leukemias (AML) is carried out. For nonpromyelocytic acute myeloid leukemias, four biomarkers are determined: the RUNX1-RUNX1T1 and CBF(-MYH11 fusion genes, the internal tandem duplication of the FLT3 gene (DIT FLT3), and the A mutation of the NPM1 gene (NPM1-A). Objective: To determine the frequency of these four biomarkers in Cuban patients with nonpromyelocytic primary acute myeloid leukemias. Methods: 91 patients were included, children and adults, who were studied at the Institute for three years from their disease debut. Complementary DNA was obtained from medullary blood RNA by reverse transcription. The corresponding fragments were amplified by polymerase chain reaction and the product was analyzed by capillary electrophoresis. Results: RUNX1-RUNX1T1 appeared in 24.2 percent; it was more frequent in pediatric patients and decreased significantly with age. CBFβ-MYH11 was found only in adults (4.8 percent). NPM1-A, accounting for 41 percent, represented the majority among adults. FLT3 DIT was observed in 21.6 por ciento and was not related to age. NPM1-A and DIT FLT3 were the disorders with the greatest concurrence. Conclusions: For the first time, the frequency of the four molecular biomarkers is described in Cuban patients with primary non-promyelocytic acute myeloid leukemias. Its characterization was similar to that described by other authors, although some peculiarities were found(AU)