RESUMEN
Disease-risk stratification and development of intensified chemotherapy protocols have substantially improved the outcome of acute lymphoblastic leukemia (ALL). However, outcomes of relapsed or refractory cases remain poor. Previous studies have discussed the oncogenic role of enhancer of zeste homolog 1 and 2 (EZH1/2), and the efficacy of dual inhibition of EZH1/2 as a treatment for hematological malignancy. Here, we investigated whether an EZH1/2 dual inhibitor, DS-3201 (valemetostat), has antitumor effects on B cell ALL (B-ALL). DS-3201 inhibited growth of B-ALL cell lines more significantly and strongly than the EZH2-specific inhibitor EPZ-6438, and induced cell cycle arrest and apoptosis in vitro. RNA-seq analysis to determine the effect of DS-3201 on cell cycle arrest-related genes expressed by B-ALL cell lines showed that DS-3201 upregulated CDKN1C and TP53INP1. CRIPSR/Cas9 knockout confirmed that CDKN1C and TP53INP1 are direct targets of EZH1/2 and are responsible for the antitumor effects of DS-3201 against B-ALL. Furthermore, a patient-derived xenograft (PDX) mouse model showed that DS-3201 inhibited the growth of B-ALL harboring MLL-AF4 significantly. Thus, DS-3201 provides another option for treatment of B-ALL.
Asunto(s)
Linfoma de Burkitt , Linfoma de Células B , Leucemia-Linfoma Linfoblástico de Células Precursoras , Humanos , Ratones , Animales , Complejo Represivo Polycomb 2 , Regulación hacia Arriba , Proteína Potenciadora del Homólogo Zeste 2 , Inhibidores Enzimáticos/farmacología , Puntos de Control del Ciclo Celular/genética , Leucemia-Linfoma Linfoblástico de Células Precursoras/tratamiento farmacológico , Leucemia-Linfoma Linfoblástico de Células Precursoras/genética , Inhibidor p57 de las Quinasas Dependientes de la Ciclina/genética , Inhibidor p57 de las Quinasas Dependientes de la Ciclina/metabolismo , Proteínas Portadoras/genética , Proteínas de Choque Térmico/genética , Proteínas de Choque Térmico/metabolismoRESUMEN
Monocytic leukemia zinc finger protein (MOZ, MYST3, or KAT6A) is a MYST-type acetyltransferase involved in chromosomal translocation in acute myelogenous leukemia (AML) and myelodysplastic syndrome. MOZ is established as essential for hematopoiesis; however, the role of MOZ in AML has not been addressed. We propose that MOZ is critical for AML development induced by MLL-AF9, MLL-AF10, or MOZ-TIF2 fusions. Moz-deficient hematopoietic stem/progenitor cells (HSPCs) transduced with an MLL-AF10 fusion gene neither formed colonies in methylcellulose nor induced AML in mice. Moz-deficient HSPCs bearing MLL-AF9 also generated significantly reduced colony and cell numbers. Moz-deficient HSPCs expressing MOZ-TIF2 could form colonies in vitro but could not induce AML in mice. By contrast, Moz was dispensable for colony formation by HOXA9-transduced cells and AML development caused by HOXA9 and MEIS1, suggesting a specific requirement for MOZ in AML induced by MOZ/MLL fusions. Expression of the Hoxa9 and Meis1 genes was decreased in Moz-deficient MLL fusion-expressing cells, while expression of Meis1, but not Hoxa9, was reduced in Moz-deficient MOZ-TIF2 AML cells. AML development induced by MOZ-TIF2 was rescued by introducing Meis1 into Moz-deficient cells carrying MOZ-TIF2. Meis1 deletion impaired MOZ-TIF2-mediated AML development. Active histone modifications were also severely reduced at the Meis1 locus in Moz-deficient MOZ-TIF2 and MLL-AF9 AML cells. These results suggest that endogenous MOZ is critical for MOZ/MLL fusion-induced AML development and maintains active chromatin signatures at target gene loci.
Asunto(s)
Leucemia Mieloide Aguda , Animales , Cromatina , Hematopoyesis , Histona Acetiltransferasas/genética , Leucemia Mieloide Aguda/genética , Leucemia Mieloide Aguda/metabolismo , Metilcelulosa , RatonesRESUMEN
Chromosome translocations involving the MLL gene are common rearrangements in leukemia. Such translocations fuse the MLL 5'-region to partner genes in frame, producing MLL-fusions that cause MLL-related leukemia. MLL-fusions activate transcription of target genes such as HoxA cluster and Meis1, but the underlying mechanisms remain to be fully elucidated. In this study, we discovered that Tip60, a MYST-type histone acetyltransferase, was required for the expression of HoxA cluster and Meis1 genes and the development of MLL-fusion leukemia. Tip60 was recruited by MLL-AF10 and MLL-ENL fusions to the Hoxa9 locus, where it acetylated H2A.Z, thereby promoting Hoxa9 gene expression. Conditional deletion of Tip60 prevented the development of MLL-AF10 and MLL-ENL leukemia, indicating that Tip60 is indispensable for the leukemogenic activity of the MLL-AF10 and MLL-ENL-fusions. Our findings provide novel insight about epigenetic regulation in the development of MLL-AF10 and MLL-ENL-fusion leukemia.
Asunto(s)
Histonas/metabolismo , Proteínas de Homeodominio/metabolismo , Leucemia Mieloide Aguda/patología , Lisina Acetiltransferasa 5/metabolismo , Proteína 1 del Sitio de Integración Viral Ecotrópica Mieloide/metabolismo , Proteína de la Leucemia Mieloide-Linfoide/metabolismo , Proteínas de Fusión Oncogénica/metabolismo , Acetilación , Animales , Epigénesis Genética , Regulación Leucémica de la Expresión Génica , Reordenamiento Génico , Histonas/genética , Proteínas de Homeodominio/genética , Humanos , Leucemia Mieloide Aguda/genética , Leucemia Mieloide Aguda/metabolismo , Lisina Acetiltransferasa 5/genética , Ratones , Proteína 1 del Sitio de Integración Viral Ecotrópica Mieloide/genética , Proteína de la Leucemia Mieloide-Linfoide/genética , Proteínas de Fusión Oncogénica/genética , Translocación GenéticaRESUMEN
Chondrosarcoma is the second most common malignant bone tumor. It is characterized by low vascularity and an abundant extracellular matrix, which confer these tumors resistance to chemotherapy and radiotherapy. There are currently no effective treatment options for relapsed or dedifferentiated chondrosarcoma, and new targeted therapies need to be identified. Isocitrate dehydrogenase (IDH) mutations, which are detected in ~50% of chondrosarcoma patients, contribute to malignant transformation by catalyzing the production of 2-hydroxyglutarate (2-HG), a competitive inhibitor of α-ketoglutarate-dependent dioxygenases. Mutant IDH inhibitors are therefore potential novel anticancer drugs in IDH mutant tumors. Here, we examined the efficacy of the inhibition of mutant IDH1 as an antitumor approach in chondrosarcoma cells in vitro and in vivo, and investigated the association between the IDH mutation and chondrosarcoma cells. DS-1001b, a novel, orally bioavailable, selective mutant IDH1 inhibitor, impaired the proliferation of chondrosarcoma cells with IDH1 mutations in vitro and in vivo, and decreased 2-HG levels. RNA-seq analysis showed that inhibition of mutant IDH1 promoted chondrocyte differentiation in the conventional chondrosarcoma L835 cell line and caused cell cycle arrest in the dedifferentiated JJ012 cell line. Mutant IDH1-mediated modulation of SOX9 and CDKN1C expression regulated chondrosarcoma tumor progression, and DS-1001b upregulated the expression of these genes via a common mechanism involving the demethylation of H3K9me3. DS-1001b treatment reversed the epigenetic changes caused by aberrant histone modifications. The present data strongly suggest that inhibition of mutant IDH1 is a promising therapeutic approach in chondrosarcoma, particularly for the treatment of relapsed or dedifferentiated chondrosarcoma.
Asunto(s)
Neoplasias Óseas/patología , Condrosarcoma/patología , Inhibidores Enzimáticos/farmacología , Código de Histonas , Isocitrato Deshidrogenasa/antagonistas & inhibidores , Mutación , Neoplasias Óseas/metabolismo , Puntos de Control del Ciclo Celular , Diferenciación Celular , Proliferación Celular , Condrosarcoma/metabolismo , Glutaratos/metabolismo , Humanos , Isocitrato Deshidrogenasa/genética , Factor de Transcripción SOX9/metabolismoRESUMEN
Eradication of chemotherapy-resistant leukemia stem cells is expected to improve treatment outcomes in patients with acute myelogenous leukemia (AML). In a mouse model of AML expressing the MOZ-TIF2 fusion, we found that Ring1A and Ring1B, components of Polycomb repressive complex 1, play crucial roles in maintaining AML stem cells. Deletion of Ring1A and Ring1B (Ring1A/B) from MOZ-TIF2 AML cells diminished self-renewal capacity and induced the expression of numerous genes, including Glis2 Overexpression of Glis2 caused MOZ-TIF2 AML cells to differentiate into mature cells, whereas Glis2 knockdown in Ring1A/B-deficient MOZ-TIF2 cells inhibited differentiation. Thus, Ring1A/B regulate and maintain AML stem cells in part by repressing Glis2 expression, which promotes their differentiation. These findings provide new insights into the mechanism of AML stem cell homeostasis and reveal novel targets for cancer stem cell therapy.
Asunto(s)
Regulación Leucémica de la Expresión Génica , Histona Acetiltransferasas/biosíntesis , Factores de Transcripción de Tipo Kruppel/biosíntesis , Leucemia Mieloide Aguda/metabolismo , Proteínas del Tejido Nervioso/biosíntesis , Coactivador 2 del Receptor Nuclear/biosíntesis , Proteínas de Fusión Oncogénica/biosíntesis , Complejo Represivo Polycomb 1/metabolismo , Ubiquitina-Proteína Ligasas/metabolismo , Animales , Diferenciación Celular , Histona Acetiltransferasas/genética , Factores de Transcripción de Tipo Kruppel/genética , Leucemia Mieloide Aguda/genética , Leucemia Mieloide Aguda/patología , Ratones , Ratones Noqueados , Proteínas del Tejido Nervioso/genética , Coactivador 2 del Receptor Nuclear/genética , Proteínas de Fusión Oncogénica/genética , Complejo Represivo Polycomb 1/genética , Ubiquitina-Proteína Ligasas/genéticaRESUMEN
IDH1 and IDH2 mutations occur frequently in acute myeloid leukemia (AML) and other cancers. The mutant isocitrate dehydrogenase (IDH) enzymes convert α-ketoglutarate (α-KG) to the oncometabolite 2-hydroxyglutarate (2-HG), which dysregulates a set of α-KG-dependent dioxygenases. To determine whether mutant IDH enzymes are valid targets for cancer therapy, we created a mouse model of AML in which mice were transplanted with nucleophosmin1 (NPM)(+/-) hematopoietic stem/progenitor cells cotransduced with four mutant genes (NPMc, IDH2/R140Q, DNMT3A/R882H, and FLT3/ITD), which often occur simultaneously in human AML patients. Conditional deletion of IDH2/R140Q blocked 2-HG production and maintenance of leukemia stem cells, resulting in survival of the AML mice. IDH2/R140Q was necessary for the engraftment or survival of NPMc(+) cells in vivo. Gene expression analysis indicated that NPMc increased expression of Hoxa9. IDH2/R140Q also increased the level of Meis1 and activated the hypoxia pathway in AML cells. IDH2/R140Q decreased the 5hmC modification and expression of some differentiation-inducing genes (Ebf1 and Spib). Taken together, our results indicated that IDH2 mutation is critical for the development and maintenance of AML stem-like cells, and they provided a preclinical justification for targeting mutant IDH enzymes as a strategy for anticancer therapy.
Asunto(s)
Proteínas de Homeodominio/metabolismo , Isocitrato Deshidrogenasa/genética , Leucemia Mieloide Aguda/genética , Proteínas de Neoplasias/metabolismo , Proteínas Nucleares/genética , Animales , Hipoxia de la Célula , Regulación Leucémica de la Expresión Génica , Humanos , Isocitrato Deshidrogenasa/metabolismo , Leucemia Mieloide Aguda/metabolismo , Ratones Endogámicos C57BL , Mutación Missense , Proteína 1 del Sitio de Integración Viral Ecotrópica Mieloide , Trasplante de Neoplasias , Proteínas Nucleares/metabolismo , Nucleofosmina , Regulación hacia ArribaRESUMEN
Acute myeloid leukemia is a clonal malignant disorder derived from a small number of leukemic stem cells (LSCs). Rearrangements of the mixed lineage leukemia (MLL) gene are found in acute myeloid leukemia associated with poor prognosis. The upregulation of Hox genes is critical for LSC induction and maintenance, but is unlikely to support malignancy and the high LSC frequency observed in MLL leukemias. The present study shows that MLL fusion proteins interact with the transcription factor PU.1 to activate the transcription of CSF-1R, which is critical for LSC activity. Acute myeloid leukemia is cured by either deletion of PU.1 or ablation of cells expressing CSF-1R. Kinase inhibitors specific for CSF-1R prolong survival time. These findings indicate that PU.1-mediated upregulation of CSF-1R is a critical effector of MLL leukemogenesis.
Asunto(s)
Carcinogénesis/genética , N-Metiltransferasa de Histona-Lisina/genética , Leucemia Mieloide Aguda/genética , Proteína de la Leucemia Mieloide-Linfoide/genética , Proteínas Proto-Oncogénicas/genética , Receptor de Factor Estimulante de Colonias de Macrófagos/genética , Transactivadores/genética , Animales , Regulación Leucémica de la Expresión Génica , Genes Homeobox , Leucemia Mieloide Aguda/mortalidad , Ratones , Ratones Endogámicos C57BL , Ratones Transgénicos , Células Madre Neoplásicas , Compuestos de Fenilurea/farmacología , Pronóstico , Receptor de Factor Estimulante de Colonias de Macrófagos/biosíntesis , Proteínas Recombinantes de Fusión/genética , Transducción de Señal , Tacrolimus/análogos & derivados , Tacrolimus/farmacología , Tiazoles/farmacología , Transcripción Genética , Activación Transcripcional , Regulación hacia ArribaRESUMEN
The CALM-AF10 fusion gene, which results from a t(10;11) translocation, is found in a variety of hematopoietic malignancies. Certain HOXA cluster genes and MEIS1 genes are upregulated in patients and mouse models that express CALM-AF10. Wild-type clathrin assembly lymphoid myeloid leukemia protein (CALM) primarily localizes in a diffuse pattern within the cytoplasm, whereas AF10 localizes in the nucleus; however, it is not clear where CALM-AF10 acts to induce leukemia. To investigate the influence of localization on leukemogenesis involving CALM-AF10, we determined the nuclear export signal (NES) within CALM that is necessary and sufficient for cytoplasmic localization of CALM-AF10. Mutations in the NES eliminated the capacity of CALM-AF10 to immortalize murine bone-marrow cells in vitro and to promote development of acute myeloid leukemia in mouse models. Furthermore, a fusion of AF10 with the minimal NES can immortalize bone-marrow cells and induce leukemia in mice. These results suggest that during leukemogenesis, CALM-AF10 plays its critical roles in the cytoplasm.
Asunto(s)
Leucemia/metabolismo , Proteínas de Ensamble de Clatrina Monoméricas/fisiología , Proteínas de Fusión Oncogénica/fisiología , Factores de Transcripción/fisiología , Secuencia de Aminoácidos , Animales , Células COS , Carcinogénesis/genética , Carcinogénesis/metabolismo , Chlorocebus aethiops , Femenino , Leucemia/genética , Leucemia/patología , Ratones , Ratones Endogámicos C57BL , Datos de Secuencia Molecular , Proteínas de Ensamble de Clatrina Monoméricas/química , Trasplante de Neoplasias , Señales de Exportación Nuclear , Células Tumorales CultivadasRESUMEN
Chromosomal translocations that involve the monocytic leukemia zinc finger (MOZ) gene are typically associated with human acute myeloid leukemia (AML) and often predict a poor prognosis. Overexpression of HOXA9, HOXA10, and MEIS1 was observed in AML patients with MOZ fusions. To assess the functional role of HOX upregulation in leukemogenesis by MOZ-TIF2, we focused on bromodomain-PHD finger protein 1 (BRPF1), a component of the MOZ complex that carries out histone acetylation for generating and maintaining proper epigenetic programs in hematopoietic cells. Immunoprecipitation analysis showed that MOZ-TIF2 forms a stable complex with BRPF1, and chromatin immunoprecipitation analysis showed that MOZ-TIF2 and BRPF1 interact with HOX genes in MOZ-TIF2-induced AML cells. Depletion of BRPF1 decreased the MOZ localization on HOX genes, resulting in loss of transformation ability induced by MOZ-TIF2. Furthermore, mutant MOZ-TIF2 engineered to lack histone acetyltransferase activity was incapable of deregulating HOX genes as well as initiating leukemia. These data indicate that MOZ-TIF2/BRPF1 complex upregulates HOX genes mediated by MOZ-dependent histone acetylation, leading to the development of leukemia. We suggest that activation of BRPF1/HOX pathway through MOZ HAT activity is critical for MOZ-TIF2 to induce AML.
Asunto(s)
Proteínas Adaptadoras Transductoras de Señales/genética , Transformación Celular Neoplásica/genética , Leucemia/genética , Proteínas Nucleares/genética , Proteínas de Fusión Oncogénica/genética , Proteínas Adaptadoras Transductoras de Señales/metabolismo , Secuencia de Aminoácidos , Animales , Línea Celular Tumoral , Transformación Celular Neoplásica/metabolismo , Proteínas de Unión al ADN , Modelos Animales de Enfermedad , Expresión Génica , Técnicas de Silenciamiento del Gen , Histona Acetiltransferasas/química , Histona Acetiltransferasas/genética , Histona Acetiltransferasas/metabolismo , Proteínas Homeobox A10 , Proteínas de Homeodominio/genética , Proteínas de Homeodominio/metabolismo , Humanos , Leucemia/metabolismo , Leucemia Mieloide Aguda/genética , Leucemia Mieloide Aguda/metabolismo , Ratones , Datos de Secuencia Molecular , Proteínas Nucleares/metabolismo , Proteínas de Fusión Oncogénica/metabolismo , Unión Proteica , Dominios y Motivos de Interacción de ProteínasRESUMEN
Leukemias and other cancers possess self-renewing stem cells that help to maintain the cancer. Cancer stem cell eradication is thought to be crucial for successful anticancer therapy. Using an acute myeloid leukemia (AML) model induced by the leukemia-associated monocytic leukemia zinc finger (MOZ)-TIF2 fusion protein, we show here that AML can be cured by the ablation of leukemia stem cells. The MOZ fusion proteins MOZ-TIF2 and MOZ-CBP interacted with the transcription factor PU.1 to stimulate the expression of macrophage colony-stimulating factor receptor (CSF1R, also known as M-CSFR, c-FMS or CD115). Studies using PU.1-deficient mice showed that PU.1 is essential for the ability of MOZ-TIF2 to establish and maintain AML stem cells. Cells expressing high amounts of CSF1R (CSF1R(high) cells), but not those expressing low amounts of CSF1R (CSF1R(low) cells), showed potent leukemia-initiating activity. Using transgenic mice expressing a drug-inducible suicide gene controlled by the CSF1R promoter, we cured AML by ablation of CSF1R(high) cells. Moreover, induction of AML was suppressed in CSF1R-deficient mice and CSF1R inhibitors slowed the progression of MOZ-TIF2-induced leukemia. Thus, in this subtype of AML, leukemia stem cells are contained within the CSF1R(high) cell population, and we suggest that targeting of PU.1-mediated upregulation of CSF1R expression might be a useful therapeutic approach.
Asunto(s)
Leucemia Mieloide Aguda/genética , Coactivador 2 del Receptor Nuclear/metabolismo , Proteínas Proto-Oncogénicas/genética , Receptores del Factor Estimulante de Colonias/genética , Transactivadores/genética , Regulación hacia Arriba , Animales , Diferenciación Celular/genética , Factores Estimulantes de Colonias/genética , Genes , Humanos , Leucemia/genética , Factor Estimulante de Colonias de Macrófagos/genética , Ratones , Ratones Transgénicos , Coactivador 2 del Receptor Nuclear/genética , Receptor de Factor Estimulante de Colonias de Macrófagos/genética , Proteínas Recombinantes de Fusión/metabolismo , Dedos de Zinc/genéticaRESUMEN
Upon DNA damage, p53 can induce either cell-cycle arrest or apoptosis. Here we show that monocytic leukemia zinc finger (MOZ) forms a complex with p53 to induce p21 expression and cell-cycle arrest. The levels of the p53-MOZ complex increased in response to DNA damage to levels that induce cell-cycle arrest. MOZ(-/-) mouse embryonic fibroblasts failed to arrest in G1 in response to DNA damage, and DNA damage-induced expression of p21 was impaired in MOZ(-/-) cells. These results suggest that MOZ is involved in regulating cell-cycle arrest in the G1 phase. Screening of tumor-associated p53 mutants demonstrated that the G279E mutation in p53 disrupts interactions between p53 and MOZ, but does not affect the DNA binding activity of p53. The leukemia-associated MOZ-CBP fusion protein inhibits p53-mediated transcription. These results suggest that inhibition of p53/MOZ-mediated transcription is involved in tumor pathogenesis and leukemogenesis.
Asunto(s)
Inhibidor p21 de las Quinasas Dependientes de la Ciclina/biosíntesis , Fase G1/fisiología , Regulación de la Expresión Génica , Histona Acetiltransferasas/metabolismo , Proteína p53 Supresora de Tumor/metabolismo , Animales , Línea Celular , Inhibidor p21 de las Quinasas Dependientes de la Ciclina/genética , Embrión de Mamíferos/citología , Embrión de Mamíferos/metabolismo , Fibroblastos/citología , Fibroblastos/metabolismo , Histona Acetiltransferasas/genética , Humanos , Ratones , Ratones Noqueados , Unión Proteica/fisiología , Proteínas Recombinantes de Fusión/genética , Proteínas Recombinantes de Fusión/metabolismo , Proteína p53 Supresora de Tumor/genéticaRESUMEN
Histone acetyltransferases (HATs) p300 and CREB-binding protein (CBP) function as co-activators for a variety of sequence-specific transcription factors, including AML1. Here, we report that homeodomain-interacting protein kinase-2 (HIPK2) forms a complex with AML1 and p300, and phosphorylates both AML1 and p300 to stimulate transcription activation as well as HAT activities. Phosphorylation of p300 is triggered by phosphorylated AML1 as well as by PU.1, c-MYB, c-JUN and c-FOS, and is inhibited by dominant-negative HIPK2. Phosphorylation of p300 and AML1 is impaired in Hipk1/2 double-deficient mouse embryos. Double-deficient mice exhibit defects in primitive/definitive hematopoiesis, vasculogenesis, angiogenesis and neural tube closure. These phenotypes are in part similar to those observed in p300- and CBP-deficient mice. HIPK2 also phosphorylates another co-activator, MOZ, in an AML1-dependent manner. We discuss a possible mechanism by which transcription factors could regulate local histone acetylation and transcription of their target genes.
Asunto(s)
Vasos Sanguíneos/embriología , Proteínas Portadoras/metabolismo , Proteínas de Ciclo Celular/metabolismo , Subunidad alfa 2 del Factor de Unión al Sitio Principal/metabolismo , Hematopoyesis , Histona Acetiltransferasas/metabolismo , Proteínas Quinasas/metabolismo , Proteínas Serina-Treonina Quinasas/metabolismo , Factores de Transcripción/metabolismo , Factores de Transcripción p300-CBP/metabolismo , Acetilación , Secuencia de Aminoácidos , Animales , Proteínas Portadoras/genética , Proteínas de Ciclo Celular/genética , Línea Celular , Subunidad alfa 2 del Factor de Unión al Sitio Principal/genética , Embrión de Mamíferos/irrigación sanguínea , Embrión de Mamíferos/metabolismo , Embrión de Mamíferos/patología , Activación Enzimática , Histona Acetiltransferasas/genética , Ratones , Ratones Noqueados , Datos de Secuencia Molecular , Neovascularización Patológica/genética , Fosforilación , Proteínas Quinasas/genética , Proteínas Serina-Treonina Quinasas/genética , Proteínas Proto-Oncogénicas/metabolismo , Proteínas Proto-Oncogénicas c-fos/metabolismo , Proteínas Proto-Oncogénicas c-jun/metabolismo , Proteínas Proto-Oncogénicas c-myb/metabolismo , Transactivadores/metabolismo , Factores de Transcripción/genética , Activación Transcripcional , Factores de Transcripción p300-CBP/genéticaRESUMEN
Monocytic leukemia zinc-finger protein (MOZ), a MYST family histone acetyltransferase, is involved in the chromosome translocations associated with acute myeloid leukemia. MOZ acts as a transcriptional coactivator for AML1, which is essential for establishment of definitive hematopoiesis. To investigate the roles of MOZ in normal hematopoiesis, we generated MOZ-null mice. MOZ-/- mice died around embryonic day 15 (E15). In MOZ-/- E14.5 embryos, hematopoietic stem cells, lineage-committed progenitors, and B lineage cells were severely reduced. On the other hand, arrest of erythroid maturation and elevated myeloid lineage populations were observed. MOZ-deficient fetal liver cells could not reconstitute hematopoiesis of recipients after transplantation. Analysis using microarray and flow cytometry revealed that expression of thrombopoietin receptor (c-Mpl), HoxA9, and c-Kit was down-regulated. These results show that MOZ is required for maintenance of hematopoietic stem cells, and that it plays a role in differentiation of erythroid and myeloid cells. Some aspects of the MOZ-/- phenotype are similar to that observed in PU.1-deficient mice. MOZ was able to interact with PU.1 and activate PU.1-dependent transcription, thus suggesting a physical and functional link between PU.1 and MOZ.
Asunto(s)
Linaje de la Célula/genética , Eritropoyesis/genética , Regulación del Desarrollo de la Expresión Génica , Células Madre Hematopoyéticas/fisiología , Histona Acetiltransferasas/fisiología , Mielopoyesis/genética , Animales , Linfocitos B/citología , Diferenciación Celular/genética , Regulación hacia Abajo , Desarrollo Embrionario/genética , Genes Letales , Células Madre Hematopoyéticas/citología , Células Madre Hematopoyéticas/metabolismo , Histona Acetiltransferasas/genética , Histona Acetiltransferasas/metabolismo , Proteínas de Homeodominio/genética , Leucemia/genética , Hígado/citología , Hígado/crecimiento & desarrollo , Ratones , Ratones Mutantes , Proteínas Oncogénicas/genética , Proteínas Proto-Oncogénicas/metabolismo , Proteínas Proto-Oncogénicas c-kit/genética , Receptores de Citocinas/genética , Receptores de Trombopoyetina , Transactivadores/metabolismo , Activación TranscripcionalRESUMEN
The AML1-CBFbeta transcription factor complex is the most frequent target of specific chromosome translocations in acute myeloid leukemia (AML). The promyelocytic leukemia (PML) gene is also frequently involved in AML-associated translocation. Here we report that a specific isoform PML I forms a complex with AML1. PML I was able to recruit AML1 and coactivator p300 in PML nuclear bodies and enhance the AML1-mediated transcription in the presence of p300. A specific C-terminal region of PML I and a C-terminal region of AML1 were found to be required for both their association and colocalization in the nuclear bodies. Overexpression of PML I stimulates myeloid cells to differentiate. These results suggest that PML I could act as a mediator for AML1 and its coactivator p300/CBP to assemble into functional complexes and, consequently, activate AML1-dependent transcription and myeloid cell differentiation.