CONGENITAL ACUTE MEGAKARYOCYTIC LEUKEMIA (AML-7)

Abstract The knowledge of clinical characteristics and prognosis of pediatric acute megakaryocytic leukemia (AMKL) with or without acquired +21 was limited. We reported 15 AMKL pediatric patients without Down Syndrome (four cases with acquired +21 and 11 cases without acquired +21) with the clinical manifestations, laboratory data, and prognosis. The clinical features and laboratory data between patients with acquired +21 and patients without acquired +21 are similar. As for prognosis, three of the 11 cases without acquired +21 obtained complete remission (CR) after 1st induction. The median follow-up time of the 11 cases was 9 months. Among four cases with acquired +21, one case gave up treatment during 1st induction, one obtained CR after 1st induction and was still alive after 49 months of follow-up. One case obtained CR after 2nd induction and was still alive for 15 months of follow-up after bone marrow transplantation, the other patient was planning for allogeneic hematopoietic stem cell transplantation (HSCT) without CR. The median follow-up time of the four cases was 12 months. None relapsed in our study. In conclusion, acquired trisomy 21 may not be an indicator for poor prognosis. Cytogenetics analysis can help us for diagnosis stratification, prognostic judgment and individualized treatment of AMKL.

Download Full-text

CBFA2T3-GLIS2 Fusion Gene Cause Dismal Clinical Course in Acute Megakaryocytic Leukemia of Down Syndrome

Blood ◽

10.1182/blood-2019-129165 ◽

2019 ◽

Vol 134 (Supplement_1) ◽

pp. 5184-5184

Author(s):

Nao Takasugi ◽

Kenichi Amano ◽

Yasuo Kubota ◽

Shota Kato ◽

Yuichi Mitani ◽

...

Keyword(s):

Down Syndrome ◽

Mutational Analysis ◽

Clinical Course ◽

Fusion Gene ◽

Snp Array ◽

Genomic Analysis ◽

Array Analysis ◽

Snp Array Analysis ◽

Acute Megakaryocytic Leukemia ◽

Gata1 Mutation

[Introduction] Acute megakaryocytic leukemia of Down syndrome (DS-AMKL) is characterized by excellent outcome with chemotherapy in contrast to non-Down syndrome-related AMKL (non-DS-AMKL). DS-AMKL and non-DS-AMKL have distinct genetic features which may underlie their different clinical characteristics. DS-AMKL is initiated by a GATA1 mutation in the transient abnormal myelopoiesis (TAM) phase and developed with further mutations of other regulators, while non-DS-AMKL is a heterogeneous group which occasionally carry chimeric oncogenes. CBFA2T3-GLIS2 fusion gene is identified in about 30% of children with non-DS-AMKL, and reported as a strong poor prognostic factor in pediatric AMKL. However, CBFA2T3-GLIS2 has never been reported in DS-AMKL and adult AMKL patients. We performed genomic analysis of DS-AMKL including atypical case with difficult clinical course. This is the first report of DS-AMKL harboring the CBFA2T3-GLIS2 fusion gene. [Case] The patient is a 1-year-old female of DS-AMKL with no prior episode of TAM. G-banding analysis revealed the karyotype both of the leukemic cells and normal tissue sample; 47, XX, +21. Chimeric genes of AML1-MTG8, CBFB-MYH, DEK-CAN, MLL-LTG4, MLL-LTG9, MLL-ENL and abnormalities of KIT and FLT3 were not detected. The chemotherapy according to the Japanese Pediatric Leukemia / Lymphoma Study Group AML-D05 protocol, gemtuzumab ozogamicin, IDA-FLAG regimen (idarubicin, fludarabine, cytarabine, filgrastim) and clofarabine-based regimen were tried, but all of them failed to achieve complete remission (CR). She underwent umbilical cord blood transplantation and relapsed on day 35 after transplantation. Once she showed a response to azacitidine, but finally she died on day 293 after transplantation. [Materials and Methods] We performed whole transcriptome sequencing (RNAseq), SNP array analysis, mutational analysis of GATA1 in 6 DS-AMKL samples, which included this refractory sample and five DS-AMKL samples with GATA1 mutations. To analyze gene expression profiling, we applied the hierarchical clustering method and principal component analysis. [Results] RNA sequencing analysis identified a fusion gene involving exon 10 of CBFA2T3 and exon 2 of GLIS2 gene in this refractory sample. This fusion gene was a result of a cryptic inversion on chromosome 16 and the in-frame fusion of both genes. The fusion transcript was validated by reverse transcription-polymerase chain reaction (RT-PCR) followed by Sanger sequencing. Though SNP array analysis confirmed 21 trisomy, it did not identify other copy number aberrations. PCR analysis did not detect GATA1 mutation in this refractory sample, which can be identified in other DS-AMKL samples. Expression analysis elucidated DS-AMKL with CBFA2T3-GLIS2 fusion had distinct expression profile from DS-AMKL with GATA1 mutations. [Discussion] CBFA2T3-GLIS2 fusion is the most common chimeric oncogene identified in non-DS-AMKL children, but has never been detected in DS-AMKL patients. Patients with non-DS-AMKL, especially holding CBFA2T3-GLIS2 fusion gene, have poorer outcomes than DS-AMKL. DS-AMKL patients generally have GATA1 mutations, show high sensitivity to chemotherapy, and can be treated with less intensive chemotherapy. However, our case had no GATA1 mutation and could not achieve CR despite intensive chemotherapy and transplantation. Thus, it is suggested this fusion gene caused the resistance to chemotherapies including hematopoietic stem cell transplantation in our case. Therefore, our case suggests patients with DS-AMKL should be surveyed genomic investigations including RNAseq and mutational analysis of GATA1 to identify their molecular biological subtypes before treatments are initiated. In case that fusion genes are detected in DS-AMKL patients, they must undergo highly intense chemotherapies, looking ahead to transplantation from the beginning of the treatment. Moreover, in case of harboring CBFA2T3-GLIS2 fusion gene, some potential therapies have been proposed, so that efficacy of such new therapies should be validated in a cell line-derived xenograft or patient-derived xenograft model. [Conclusion] DS-AMKL is generally known to show superior outcome, but DS-AMKL without GATA1 mutation and with CBFA2T3-GLIS2 fusion gene shows resistance to chemotherapies. For DS-AMKL patients, it is desirable to perform genomic analysis including RNAseq before chemotherapy. Disclosures No relevant conflicts of interest to declare.

Download Full-text

Acute Megakaryocytic Leukemia Associated with Primary Mediastinal Germ Cell Tumor: A Case Report

Annals of Oncology ◽

10.1016/s0923-7534(20)32478-9 ◽

2012 ◽

Vol 23 ◽

pp. xi154

Author(s):

E. Noguchi ◽

Y. Omuro ◽

M. Kudo ◽

T. Shimoyama ◽

E. Sasaki ◽

...

Keyword(s):

Case Report ◽

Germ Cell ◽

Germ Cell Tumor ◽

Cell Tumor ◽

Mediastinal Germ Cell Tumor ◽

Acute Megakaryocytic Leukemia

Download Full-text

Hemophagocytosis in Acute Megakaryocytic Leukemia

Journal of Pediatric Hematology/Oncology ◽

10.1097/mph.0b013e31829f4072 ◽

2013 ◽

Vol 35 (7) ◽

pp. 578 ◽

Cited By ~ 1

Author(s):

Arzu Akyay

Keyword(s):

Acute Megakaryocytic Leukemia

Download Full-text

Overexpression of GATA1 Confers Chemotherapy Resistance in Pediatric Acute Megakaryocytic Leukemia.

Blood ◽

10.1182/blood.v114.22.2039.2039 ◽

2009 ◽

Vol 114 (22) ◽

pp. 2039-2039

Author(s):

Holly Edwards ◽

Chengzhi Xie ◽

Alan Dombkowski ◽

Maggie Keller ◽

Mark Stout ◽

...

Keyword(s):

Cell Line ◽

Histone Deacetylase Inhibitors ◽

Target Genes ◽

Negative Control ◽

Pi3 Kinase ◽

Luciferase Reporter ◽

Toxic Dose ◽

Protein Levels ◽

Acute Megakaryocytic Leukemia ◽

Shrna Knockdown

Abstract Abstract 2039 Poster Board II-16 Acute megakaryocytic leukemia (AMkL; M7) is a biologically heterogeneous form of AML, representing ∼10% of pediatric and 1-2% of adult AML cases. AMkL is the most common AML subtype of children with Down syndrome (DS). DS children with AMkL have an excellent prognosis with EFS rates of 80-100% when treated with ara-C/anthracycline-based protocols, in contrast to the <30% EFS rates of non-DS children with AMkL. This also contrasts to the ∼50% EFS rates of non-DS children with AML overall, indicating that AMkL is an extremely poor risk group amongst non-DS children with AML despite the use of intensive chemotherapy-based protocols. These clinical data make a compelling argument that new therapies are essential to improve the treatment outcome of this aggressive disease. Acquired somatic mutations of the transcription factor gene, GATA1 (localized to Xp11.23), have been detected uniformly in nearly all DS AMkL cases, but not in non-DS AML and non-AMkL DS leukemia cases. The net effect of GATA1 mutations is an introduction of early stop codons and synthesis of a shorter GATA1 protein (designated GATA1s) that has altered transactivation activity, potentially contributing to the uncontrolled proliferation of immature megakaryocytes. It is conceivable that the altered GATA1 function between DS and non-DS AMkL may account for differential expression of GATA1 target genes in these two groups of patients. On the other hand, overexpression of GATA1 in megakaryoblasts from non-DS children with AMkL compared to myeloblasts from non-DS children with other subtypes of AML may contribute to differences in chemotherapy sensitivity via regulation of GATA1 target genes. We previously reported that GATA1 mutations in DS AMkL are associated with decreased expression of cytidine deaminase (encodes an enzyme which can convert ara-C to ara-U, the inactive form of the drug), thus contributing to the enhanced ara-C sensitivity of DS AMkL blasts. Further, when GATA1 was ectopically expressed in a DS AMkL cell line, CMK, it caused significantly increased resistance to ara-C. In the present study, we confirmed overexpression of GATA1 in non-DS AMkL blasts compared to non-DS AML blasts by real-time RT-PCR quantitation of GATA1 transcripts in our cohort of patient samples. shRNA knockdown of GATA1 in a non-DS AMkL cell line, Meg-01, resulted in significantly increased sensitivities to ara-C and daunorubicin, the two main drugs used for AML treatment, and significantly increased basal level apoptosis. This was accompanied by significantly decreased Bcl-xL transcript and protein levels in the GATA1 shRNA knockdown clones compared to a shRNA negative control. Binding of GATA1 to the two GATA elements in Bcl-x promoter and transactivation of Bcl-x promoter activity by GATA1 was demonstrated by ChIP assays and luciferase reporter assays, respectively, in Meg-01 cells. In our cohort of non-DS AMkL and AML patient samples, significant overexpression of Bcl-xL in non-DS AMkL compared to non-DS AML cases and a significant correlation between Bcl-xL and GATA1 transcripts were detected. Besides Bcl-xL, additional GATA1 targets (e.g. TNF) related to apoptosis were also identified by gene expression and ChIP-on-ChIP microarray analyses. Interestingly, our microarray data also suggest that GATA1 may have an impact on PI3-kinase/Akt pathway through modulating directly or indirectly a group of genes within the pathway. Western blotting revealed increased phosphorylation of Akt in the GATA1 knockdown clones compared to the negative control cells. Previous studies reported that histone deacetylase inhibitors (HDACIs) treatment causes hyperacetylation and subsequent degradation of GATA1, suggesting that these agents may be effective in targeting GATA1 in AMkL. Treatment of Meg-01 cells with an HDACI, valproic acid (VPA), resulted in decreased protein levels for GATA1 and Bcl-xL and increased phosphorylation of Akt. Co-treatment of Meg-01 cells with VPA and ara-C resulted in synergistic induction of apoptosis and activation of caspase-3. This drug synergy was amplified when a non-toxic dose of the PI3-kinase inhibitor LY294002 was added. Our results demonstrate that GATA1 causes resistance to chemotherapy in non-DS AMkL by promoting AMkL blast survival through regulating its target genes. Treatment of AMkL may be improved by integrating HDACI and PI3-kinase or Akt inhibitors into the chemotherapy of this disease. Disclosures: No relevant conflicts of interest to declare.

Download Full-text

High PRMT1 Expression Promotes the Progression of Acute Megakaryocytic Leukemia Via Controlling Metabolic Pathways

Blood ◽

10.1182/blood.v128.22.1551.1551 ◽

2016 ◽

Vol 128 (22) ◽

pp. 1551-1551

Author(s):

Hairui Su ◽

Han Guo ◽

Ngoc-Tung Tran ◽

Minkui Luo ◽

Xinyang Zhao

Keyword(s):

Fatty Acid ◽

Fatty Acid Oxidation ◽

Metabolic Pathways ◽

Metabolic Stress ◽

Metabolic Reprogramming ◽

Metabolic Inhibitors ◽

Acid Oxidation ◽

Epigenetic Changes ◽

Acute Megakaryocytic Leukemia ◽

Megakaryocyte Differentiation

Abstract Metabolic reprogramming is needed not only to accommodate but also to drive leukemia progression. Yet very little is known on genetic factors other than IDH1 mutations, which can drive leukemogenesis via metabolic reprogramming. Here, we will present data to suggest that protein arginine methyltransferases 1 (PRMT1) is a driver for acute megakaryocytic leukemia via reprogramming metabolism. PRMT1 is highly expressed in megakaryocyte-erythrocyte progenitor cells and downregulated during the terminal differentiation of megakaryocytes. Constitutively high expression of PRMT1 in acute megakaryoblastic leukemia (AMKL) blocks megakaryocyte differentiation. PRMT1 upregulates RBM15 protein level via methylation-dependent ubiquitylation pathway (Zheng et al. Elife, 2015). In this presentation, we discovered that metabolic stress such as hypoxia downregulates PRMT1 protein level. Thus, metabolic stress is the upstream signal for the PRMT1-RBM15 pathway. We have identified that RBM15 specifically binds to 3'UTR of mRNAs of genes involved in metabolic pathways. Using RNA-immunoprecipitation with anti-RBM15 antibody and real-time PCR assays, we validated that RBM15 binds to mRNAs of genes involved in fatty acid oxidation and glycolysis. We transduced PRMT1 into an RBM15-MKL1 expressing cell line 6133. Overexpression of PRMT1 renders 6133 cells to grow in a cytokine-independent manner with increased mitochondria biogenesis, which in turn produces higher concentration of ATP in our metabolomic analysis. Based on the analysis of metabolomics data and RBM15-target genes, we conclude that PRMT1 promotes the usage of glucose as bioenergy via oxidative phosphorylation and inhibits fatty acid oxidation. Given that acetyl-coA is higher in PRMT1 expressing 6133 cells, we asked whether histone acetylation is upregulated in PRMT1 overexpressed 6133 cells. Indeed, we found higher histone acetylation level in PRMT1 highly expressed cells. We also found that propionylated histone is reduced, which is consistent with reduced fatty acid oxidation. Propionyl-CoA molecules are produced from fatty acids with odd carbon numbers. Thus PRMT1-mediated metabolic reprogramming changes epigenetic programming during leukemia progression. Intriguing, we also found PRMT1 overexpression enhances histone H3S10 phosphorylation via methylation-dependent ubiquitylation of DUSP4. DUSP4 promotes polyploidy during megakaryocyte differentiation. Thus PRMT1 caused profound epigenetic changes to promote leukemogenesis. In this vein, we established mouse AMKL models by bone marrow transplantation of 6133 cells as well as human AMKL patient samples respectively. Using this mouse model, we tested PRMT1 inhibitors, acetyltransferase inhibitors as well as other metabolic inhibitors. Treating cells with PRMT1 inhibitors as well as metabolic inhibitors promote MK differentiation of AMKL leukemia cells. Metabolomics analysis of cells recovered from mouse models will be discussed in the presentation. In summary, our data demonstrated that PRMT1 is a major sensor for metabolic stress and that PRMT1 in turn reprograms metabolic pathways to bring epigenetic changes in leukemogenesis. Therefore, targeting PRMT1 and downstream PRMT1-regulated metabolic pathways will offer new avenues in treating acute megakaryocytic leukemia and other hematological malignancies with defective megakaryocyte differentiation. Disclosures No relevant conflicts of interest to declare.

Download Full-text

Insights into the manifestations, outcomes, and mechanisms of leukemogenesis in Down syndrome

Blood ◽

10.1182/blood-2008-11-163501 ◽

2009 ◽

Vol 113 (12) ◽

pp. 2619-2628 ◽

Cited By ~ 152

Author(s):

Sébastien Malinge ◽

Shai Izraeli ◽

John D. Crispino

Keyword(s):

Down Syndrome ◽

Patient Outcomes ◽

Clinical Manifestations ◽

Therapeutic Strategies ◽

Genetic Mutations ◽

High Risk Population ◽

Myeloproliferative Disease ◽

Lymphoid Leukemia ◽

Lymphoid Malignancies ◽

Acute Megakaryocytic Leukemia

AbstractChildren with Down syndrome (DS) show a spectrum of clinical anomalies, including cognitive impairment, cardiac malformations, and craniofacial dysmorphy. Moreover, hematologists have also noted that these children commonly show macrocytosis, abnormal platelet counts, and an increased incidence of transient myeloproliferative disease (TMD), acute megakaryocytic leukemia (AMKL), and acute lymphoid leukemia (ALL). In this review, we summarize the clinical manifestations and characteristics of these leukemias, provide an update on therapeutic strategies and patient outcomes, and discuss the most recent advances in DS-leukemia research. With the increased knowledge of the way in which trisomy 21 affects hematopoiesis and the specific genetic mutations that are found in DS-associated leukemias, we are well on our way toward designing improved strategies for treating both myeloid and lymphoid malignancies in this high-risk population.

Download Full-text