scholarly journals The megakaryocytic transcription factor ARID3A suppresses leukemia pathogenesis

Blood ◽  
2021 ◽  
Author(s):  
Oriol Alejo-Valle ◽  
Karoline Weigert ◽  
Raj Bhayadia ◽  
Michelle Ng ◽  
Hasan Issa ◽  
...  
Keyword(s):  
Transcription Factor ◽  
Transcriptional Repression ◽  
Reverse Genetics ◽  
Erythroid Differentiation ◽  
Chromosome 21 ◽  
Hematopoietic Stem ◽  
Megakaryocytic Differentiation ◽  
Megakaryoblastic Leukemia ◽  
Multiple Routes ◽  
Induced Apoptosis

Given the plasticity of hematopoietic stem/progenitor cells, multiple routes of differentiation must be blocked during acute myeloid leukemia pathogenesis - the molecular basis of which is incompletely understood. Here we report that post-transcriptional repression of the transcription factor ARID3A by miR-125b is a key event in megakaryoblastic leukemia (AMKL) pathogenesis. AMKL is frequently associated with trisomy 21 and GATA1 mutations (GATA1s), and children with Down syndrome are at a high risk of developing this disease. We show that chromosome 21-encoded miR-125b synergizes with Gata1s to drive leukemogenesis in this context. Leveraging forward and reverse genetics, we uncover Arid3a as the main miR-125b target behind this synergy. We demonstrate that, during normal hematopoiesis, this transcription factor promotes megakaryocytic differentiation in concert with GATA1 and mediates TGFβ-induced apoptosis and cell cycle arrest in complex with SMAD2/3. While Gata1s mutations perturb erythroid differentiation and induce hyperproliferation of megakaryocytic progenitors, intact ARID3A expression assures their megakaryocytic differentiation and growth restriction. Upon knockdown, these tumor suppressive functions are revoked, causing a dual megakaryocytic/erythroid differentiation blockade and subsequently AMKL. Inversely, restoring ARID3A expression relieves the megakaryocytic differentiation arrest in AMKL patient-derived xenografts. This work illustrates how mutations in lineage-determining transcription factors and perturbation of post-transcriptional gene regulation can interplay to block multiple routes of hematopoietic differentiation and cause leukemia. In AMKL, surmounting this differentiation blockade through restoration of the tumor suppressor ARID3A represents a promising strategy for treating this lethal pediatric disease.

scholarly journals The megakaryocytic transcription factor ARID3A suppresses leukemia pathogenesis

2021 ◽  
Author(s):  
Oriol Alejo-Valle ◽  
Karoline Weigert ◽  
Raj Bhayadia ◽  
Michelle Ng ◽  
Stephan Emmrich ◽  
...  
Keyword(s):  
Transcription Factor ◽  
Transcriptional Repression ◽  
Reverse Genetics ◽  
Erythroid Differentiation ◽  
Chromosome 21 ◽  
Hematopoietic Stem ◽  
Megakaryocytic Differentiation ◽  
Megakaryoblastic Leukemia ◽  
Multiple Routes ◽  
Induced Apoptosis

Given the plasticity of hematopoietic stem/progenitor cells, multiple routes of differentiation must be blocked during acute myeloid leukemia pathogenesis - the molecular basis of which is incompletely understood. Here we report that post-transcriptional repression of transcription factor ARID3A by miR-125b is a key event in megakaryoblastic leukemia (AMKL) pathogenesis. AMKL is frequently associated with trisomy 21 and GATA1 mutations (GATA1s), and children with Down syndrome are at a high risk of developing this disease. We show that chromosome 21-encoded miR-125b synergizes with Gata1s to drive leukemogenesis in this context. Leveraging forward and reverse genetics, we uncover Arid3a as the main miR-125b target underlying this synergy. We demonstrate that during normal hematopoiesis this transcription factor promotes megakaryocytic differentiation in concert with GATA1 and mediates TGFbeta-induced apoptosis and cell cycle arrest in complex with SMAD2/3. While Gata1s mutations perturb erythroid differentiation and induce hyperproliferation of megakaryocytic progenitors, intact ARID3A expression assures their megakaryocytic differentiation and growth restriction. Upon knockdown, these tumor suppressive functions are revoked, causing a dual megakaryocytic/erythroid differentiation blockade and subsequently AMKL. Inversely, restoring ARID3A expression relieves the megakaryocytic differentiation arrest in AMKL patient-derived xenografts. This work illustrates how mutations in lineage-determining transcription factors and perturbation of post-transcriptional gene regulation interplay to block multiple routes of hematopoietic differentiation and cause leukemia. Surmounting this differentiation blockade in megakaryoblastic leukemia by restoring the tumor suppressor ARID3A represents a promising strategy for treating this lethal pediatric disease.

The ERG Gene in Normal and Malignant Megakaryopoiesis.

Blood ◽  
2004 ◽  
Vol 104 (11) ◽  
pp. 3431-3431
Author(s):  
Liat Rainis ◽  
Esther Rosenthal ◽  
Sabine Strehl ◽  
Oskar A. Haas ◽  
Shai Izraeli
Keyword(s):  
Transcription Factor ◽  
Down Syndrome ◽  
Ectopic Expression ◽  
K562 Cells ◽  
Chromosome 21 ◽  
Leukemic Cells ◽  
Megakaryocytic Differentiation ◽  
Megakaryoblastic Leukemia ◽  
High Incidence ◽  
Reporter Assays

Abstract About 10% of patients with Down syndrome (DS) are born with a transient megakaryoblastic leukemia. We (Rainis et al. Blood2003; 102:981) and others have demonstrated acquired intrauterine inactivating mutations in the X-linked gene GATA1 in these leukemias. The gene(s) on chromosome 21 that promote the proliferation of these abnormal megakaryoblasts are presently unknown. We hypothesize such a role to the ets transcription factor ERG that is located at the critical DS region on chromosome 21. This hypothesis is based on the close homology between ERG and FLI-1, a transcription factor that induces megakaryopoiesis through cooperation with GATA1. ERG occasionally replaces FLI-1 in the translocation with EWS in Ewing sarcoma and is also involved in the leukemogenic translocation FUS-ERG. However no role for ERG in hematopoiesis has been demonstrated so far. Here we show that (a) ERG is expressed in platelets and in megakaryoblastic cell lines, including those derived from Down Syndrome. (b) ERG is expressed in primary leukemic cells from DS patients. (c) Its expression is induced upon megakaryocytic differentiation (d) ERG collaborates with GATA1 in activation of megakaryocytic promoters in reporter assays; and (e) Forced ectopic expression of ERG in K562 cells induces megakaryocytic differentiation. Thus we provide the first evidence that the ERG gene participate in megakaryopoiesis. Promotion of megakaryopoiesis caused by its overexpression in DS coupled with the differentiation arrest induced by the acquired mutation in GATA1 may explain the high incidence of a congenital megakaryoblastic proliferation disorder in Down Syndrome.

scholarly journals Coordinate loss of a microRNA and protein-coding gene cooperate in the pathogenesis of 5q− syndrome

Blood ◽  
2011 ◽  
Vol 118 (17) ◽  
pp. 4666-4673 ◽  
Author(s):  
Madhu S. Kumar ◽  
Anupama Narla ◽  
Atsushi Nonami ◽  
Ann Mullally ◽  
Nadya Dimitrova ◽  
...  
Keyword(s):  
Transcription Factor ◽  
Erythroid Differentiation ◽  
Deletion Syndrome ◽  
Chromosomal Deletion ◽  
Reciprocal Effect ◽  
Protein Coding ◽  
Megakaryocytic Differentiation ◽  
Molecular Abnormalities ◽  
Human Malignancy ◽  
The Common

Abstract Large chromosomal deletions are among the most common molecular abnormalities in cancer, yet the identification of relevant genes has proven difficult. The 5q− syndrome, a subtype of myelodysplastic syndrome (MDS), is a chromosomal deletion syndrome characterized by anemia and thrombocytosis. Although we have previously shown that hemizygous loss of RPS14 recapitulates the failed erythroid differentiation seen in 5q− syndrome, it does not affect thrombocytosis. Here we show that a microRNA located in the common deletion region of 5q− syndrome, miR-145, affects megakaryocyte and erythroid differentiation. We find that miR-145 functions through repression of Fli-1, a megakaryocyte and erythroid regulatory transcription factor. Patients with del(5q) MDS have decreased expression of miR-145 and increased expression of Fli-1. Overexpression of miR-145 or inhibition of Fli-1 decreases the production of megakaryocytic cells relative to erythroid cells, whereas inhibition of miR-145 or overexpression of Fli-1 has a reciprocal effect. Moreover, combined loss of miR-145 and RPS14 cooperates to alter erythroid-megakaryocytic differentiation in a manner similar to the 5q− syndrome. Taken together, these findings demonstrate that coordinate deletion of a miRNA and a protein-coding gene contributes to the phenotype of a human malignancy, the 5q− syndrome.

scholarly journals Histone Demethylase LSD1-Mediated Repression of GATA-2 Is Critical for Erythroid Differentiation

Blood ◽  
2014 ◽  
Vol 124 (21) ◽  
pp. 5128-5128
Author(s):  
Yidi Guo ◽  
Yue Li ◽  
Tianrui Huang ◽  
Dongxue Liang ◽  
Zhe Li ◽  
...  
Keyword(s):  
Transcription Factor ◽  
Cell Differentiation ◽  
Gene Locus ◽  
Epigenetic Modification ◽  
Expression Patterns ◽  
Erythroid Differentiation ◽  
Stem Cell Differentiation ◽  
Erythroid Cell ◽  
Embryonic Stem Cell Differentiation ◽  
Hematopoietic Stem

Abstract GATA-2 transcription factor is predominantly expressed in hematopoietic stem and progenitor cells (HS/PCs), and counteracts erythroid specific transcription factor GATA-1 to modulate proliferation and differentiation of hematopoietic cells. During hematopoietic cell differentiation, GATA-2 exhibits dynamic expression patterns, regulated by collaborations between GATA-1 and epigenetic regulators. Here, we show that histone specific demethylase1 (LSD1) regulates the expression of GATA-2 gene during erythroid differentiation. Knockdown of LSD1 leads to increased GATA-2 expression and inhibits induced MEL and embryonic stem cell differentiation. Furthermore, we demonstrate that LSD1 binds at the 1S promoter of GATA-2 gene locus, and suppresses GATA-2 expression through histone demethylation. Thus, our data reveals that LSD1 mediates erythroid cell differentiation by epigenetic modification of GATA-2 gene locus. Disclosures No relevant conflicts of interest to declare.

scholarly journals Highly penetrant myeloproliferative disease in the Ts65Dn mouse model of Down syndrome

Blood ◽  
2008 ◽  
Vol 111 (2) ◽  
pp. 767-775 ◽  
Author(s):  
Gina Kirsammer ◽  
Sarah Jilani ◽  
Hui Liu ◽  
Elizabeth Davis ◽  
Sandeep Gurbuxani ◽  
...  
Keyword(s):  
Down Syndrome ◽  
Mouse Model ◽  
Gene Dosage ◽  
Hematologic Malignancies ◽  
Chromosome 21 ◽  
Myeloproliferative Disease ◽  
Ts65dn Mouse ◽  
Hematopoietic Stem ◽  
Megakaryoblastic Leukemia ◽  
Increased Risk

Children with Down syndrome (DS) display macrocytosis, thrombocytosis, and a 500-fold increased risk of developing megakaryocytic leukemia; however, the specific effects of trisomy 21 on hematopoiesis remain poorly defined. To study this question, we analyzed blood cell development in the Ts65Dn mouse model of DS. Ts65Dn mice are trisomic for 104 orthologs of Hsa21 genes and are the most widely used mouse model for DS. We discovered that Ts65Dn mice display persistent macrocytosis and develop a myeloproliferative disease (MPD) characterized by profound thrombocytosis, megakaryocyte hyperplasia, dysplastic megakaryocyte morphology, and myelofibrosis. In addition, these animals bear distorted hematopoietic stem and myeloid progenitor cell compartments compared with euploid control littermates. Of the 104 trisomic genes in Ts65Dn mice, Aml1/Runx1 attracts considerable attention as a candidate oncogene in DS–acute megakaryoblastic leukemia (DS-AMKL). To determine whether trisomy for Aml1/Runx1 is essential for MPD, we restored disomy at the Aml1/Runx1 locus in the Ts65Dn strain. Surprisingly, trisomy for Aml1/Runx1 is not required for megakaryocyte hyperplasia and myelofibrosis, suggesting that trisomy for one or more of the remaining genes can promote this disease. Our studies demonstrate the potential of DS mouse models to improve our understanding of chromosome 21 gene dosage effects in human hematologic malignancies.

scholarly journals Fli-1, an Ets-Related Transcription Factor, Regulates Erythropoietin-Induced Erythroid Proliferation and Differentiation: Evidence for Direct Transcriptional Repression of the Rb Gene during Differentiation

1999 ◽  
Vol 19 (6) ◽  
pp. 4452-4464 ◽  
Author(s):  
Ami Tamir ◽  
Jeff Howard ◽  
Rachel R. Higgins ◽  
You-Jun Li ◽  
Lloyd Berger ◽  
...  
Keyword(s):  
Transcription Factor ◽  
Transcriptional Repression ◽  
Target Genes ◽  
Leukemia Virus ◽  
Constitutive Expression ◽  
Erythroid Differentiation ◽  
Consensus Binding Site ◽  
Erythroid Progenitor ◽  
Proliferation And Differentiation ◽  
Related Transcription Factor

ABSTRACT Erythropoietin (Epo) is a major regulator of erythropoiesis that alters the survival, proliferation, and differentiation of erythroid progenitor cells. The mechanism by which these events are regulated has not yet been determined. Using HB60, a newly established erythroblastic cell line, we show here that Epo-induced terminal erythroid differentiation is associated with a transient downregulation in the expression of the Ets-related transcription factor Fli-1. Constitutive expression of Fli-1 in HB60 cells, similar to retroviral insertional activation of Fli-1 observed in Friend murine leukemia virus (F-MuLV)-induced erythroleukemia, blocks Epo-induced differentiation while promoting Epo-induced proliferation. These results suggest that Fli-1 modulates the response of erythroid cells to Epo. To understand the mechanism by which Fli-1 regulates erythropoiesis, we searched for downstream target genes whose expression is regulated by this transcription factor. Here we show that the retinoblastoma (Rb) gene, which was previously shown to be involved in the development of mature erythrocytes, contains a Fli-1 consensus binding site within its promoter. Fli-1 binds to this cryptic Ets consensus site within the Rb promoter and transcriptionally represses Rb expression. Both the expression level and the phosphorylation status of Rb are consistent with the response of HB60 cells to Epo-induced terminal differentiation. We suggest that the negative regulation ofRb by Fli-1 could be one of the critical determinants in erythroid progenitor cell differentiation that is specifically deregulated during F-MuLV-induced erythroleukemia.

scholarly journals FKHR-L1 can act as a critical effector of cell death induced by cytokine withdrawal

2002 ◽  
Vol 156 (3) ◽  
pp. 531-542 ◽  
Author(s):  
Pascale F. Dijkers ◽  
Kim U. Birkenkamp ◽  
Eric W.-F. Lam ◽  
N. Shaun B. Thomas ◽  
Jan-Willem J. Lammers ◽  
...  
Keyword(s):  
Cell Death ◽  
Transcription Factor ◽  
Membrane Integrity ◽  
Ectopic Expression ◽  
Forkhead Transcription Factor ◽  
Cytochrome C Release ◽  
Potent Inducer ◽  
Hematopoietic Stem ◽  
Induction Of Apoptosis ◽  
Induced Apoptosis

Survival signals elicited by cytokines include the activation of phosphatidylinositol 3-kinase (PI3K), which in turn promotes the activation of protein kinase B (PKB). Recently, PKB has been demonstrated to phosphorylate and inactivate forkhead transcription factor FKHR-L1, a potent inducer of apoptosis. To explore the mechanisms underlying the induction of apoptosis after cytokine withdrawal or FKHR-L1 activation, we used a cell line in which FKHR-L1 activity could be specifically induced. Both cytokine withdrawal and FKHR-L1 activation induced apoptosis, which was preceded by an upregulation in p27KIP1 and a concomitant decrease in cells entering the cell cycle. Induction of apoptosis by both cytokine withdrawal and activation of FKHR-L1 correlated with the disruption of mitochondrial membrane integrity and cytochrome c release. This was preceded by upregulation of the pro-apoptotic Bcl-2 family member Bim. Ectopic expression of an inhibitory mutant of FKHR-L1 substantially reduced the levels of apoptosis observed after cytokine withdrawal. Activation of PKB alone was sufficient to promote cell survival, as measured by maintenance of mitochondrial integrity and the resultant inhibition of effector caspases. Furthermore, hematopoietic stem cells isolated from Bim−/− mice exhibited reduced levels of apoptosis upon inhibition of PI3K/PKB signaling. These data demonstrate that activation of FKHR-L1 alone can recapitulate all known elements of the apoptotic program normally induced by cytokine withdrawal. Thus PI3K/PKB–mediated inhibition of this transcription factor likely provides an important mechanism by which survival factors act to prevent programmed cell death.

A Molecular Signature of the Transcription Factor GATA1 in Acute Megakaryoblastic Leukemia of Childhood.

Blood ◽  
2004 ◽  
Vol 104 (11) ◽  
pp. 1117-1117
Author(s):  
Jean-Pierre Bourquin ◽  
Claudia Langebrake ◽  
Aravind Subramanian ◽  
Xiaochun Li ◽  
Dirk Reinhardt ◽  
...  
Keyword(s):  
Gene Expression ◽  
Transcription Factor ◽  
Target Genes ◽  
Cellular Proliferation ◽  
Expression Profiles ◽  
Chromosome 21 ◽  
Molecular Signature ◽  
Consensus Clustering ◽  
Acute Megakaryoblastic Leukemia ◽  
Megakaryoblastic Leukemia

Abstract To investigate the pathogenesis of acute megakaryoblastic leukemia, AML M7 (M7), we analyzed the gene expression profiles of 113 patient samples on Affymetrix U133A GeneChips. Classification by unsupervised clustering discriminates 70 M7 samples from 12 with other AML FAB subtypes, 3 normal controls, 10 normal and remission samples of patients with Down Syndrome (DS) and 18 ALL samples from DS patients. Further, M7 subclasses can be identified. DS samples (21 DS-M7 and 9 transient myeloproliferative disease (TMD) samples) cluster apart from non-DS M7 samples, with a few exceptions, most notably the 4 M7 samples with the translocation t(1;22). Smaller subgroups can be detected by consensus clustering in DS and non-DS M7. The DS-non-DS distinction is not driven by differential expression of chromosome 21 genes, in particular RUNX1 expression levels are not increased in DS. Consistent with differences observed by flow cytometry, DS samples show a higher expression of ANK1, GYPA, GYPB and CD36, while non-DS M7 samples have higher VWF and CD34 expression, reflecting known morphologic differences. The hematopoietic transcription factor GATA1 is overexpressed in DS M7/TMD when compared to non-DS M7s or controls, and is among the most significant markers of the DS class. The mutation of GATA1 that is characteristic for DS is likely to affect its transcriptome specifically. By nearest neighbour analysis, about 300 genes follow the pattern of the GATA1 gene expression within a significant range by permutation testing. This GATA-1 signature is highly enriched in the DS samples and includes several known target genes of GATA1, such as GATA2, GYPA, ANK1 and ALAD. This approach should lead to the identification of genes contributing to cellular proliferation and differentiation in the context of the GATA1 mutation of DS M7.

An Early Block to Erythro-Megakaryocytic Development Conferred by Loss of Transcription Factor GATA-1.

Blood ◽  
2005 ◽  
Vol 106 (11) ◽  
pp. 1732-1732
Author(s):  
David L. Stachura ◽  
Stella T. Chou ◽  
Mitchell J. Weiss
Keyword(s):  
Transcription Factor ◽  
Early Stage ◽  
Embryonic Stem ◽  
Erythroid Progenitor ◽  
Megakaryocytic Differentiation ◽  
Megakaryoblastic Leukemia ◽  
Surface Phenotype ◽  
Maturation In Vitro

Abstract Transcription factor GATA-1 is essential at multiple stages of hematopoiesis. Murine gene targeting and analysis of naturally occurring human mutations demonstrate that GATA-1 is required for the maturation of committed erythroid precursors and megakaryocytes. Prior studies also suggest additional, poorly defined, roles for GATA-1 at earlier stages of erythro-megakaryocytic development. To investigate these functions further, we studied hematopoietic differentiation of Gata1− murine embryonic stem cells on OP9 stroma with the cytokine thrombopoietin (TPO) present. Initially, the Gata1− cultures generated a wave of mutant megakaryocytes, but these were rapidly overgrown by a unique population of TPO-dependent blasts that continued to proliferate for more than 6 months in culture. These immature Gata1− cells arose reproducibly in culture without growth lag or crisis, indicating that they derive directly from loss of GATA-1 and not from random genetic events acquired during cell culture. The cells express transcription factors GATA-2, FOG-1 and PU.1 and exhibit the surface phenotype Lin−, Sca1−, IL7R−, CD41+, cKit+, CD9+, and GPIblow. Importantly, upon restoration of GATA-1 function, these cells undergo both erythroid and megakaryocytic differentiation, as assessed by morphology, ultrastructural analysis and the induction of lineage-specific markers. Clonal analysis shows that individual cells maintain the capacity for erythro-megakaryocytic differentiation. Hence, we term this unique population G1ME for Gata1− -Megakaryocyte-Erythroid. To determine if G1ME cells are present in vivo, we analyzed E13.5 fetal livers of Gata1−/Gata1wild-type chimeric embryos. Flow cytometry analysis demonstrates an expanded population of cells expressing the G1ME surface phenotype. Individual cells within this population also exhibit TPO-dependency, extensive proliferative capacity and GATA-1-dependent biphenotypic erythro-megakaryocytic maturation in vitro. Our findings indicate that the loss of GATA-1 impairs the maturation of a specific megakaryocyte-erythroid progenitor. This defines a new role for GATA-1 at a relatively early stage of hematopoiesis and provides potential insight into recent discoveries that human GATA1 mutations promote acute megakaryoblastic leukemia (AMKL), a clonal malignancy with features of both erythroid and megakaryocyte maturation.

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