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Yan M, Liu M, Davis AG, Stoner SA, Zhang DE. Single-cell RNA sequencing of a new transgenic t(8;21) preleukemia mouse model reveals regulatory networks promoting leukemic transformation. Leukemia 2024; 38:31-44. [PMID: 37838757 PMCID: PMC10776403 DOI: 10.1038/s41375-023-02063-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2023] [Revised: 09/22/2023] [Accepted: 10/05/2023] [Indexed: 10/16/2023]
Abstract
T(8;21)(q22;q22), which generates the AML1-ETO fusion oncoprotein, is a common chromosomal abnormality in acute myeloid leukemia (AML) patients. Despite having favorable prognosis, 40% of patients will relapse, highlighting the need for innovative models and application of the newest technologies to study t(8;21) leukemogenesis. Currently, available AML1-ETO mouse models have limited utility for studying the pre-leukemic stage because AML1-ETO produces mild hematopoietic phenotypes and no leukemic transformation. Conversely, overexpression of a truncated variant, AML1-ETO9a (AE9a), promotes fully penetrant leukemia and is too potent for studying pre-leukemic changes. To overcome these limitations, we devised a germline-transmitted Rosa26 locus AE9a knock-in mouse model that moderately overexpressed AE9a and developed leukemia with long latency and low penetrance. We observed pre-leukemic alterations in AE9a mice, including skewing of progenitors towards granulocyte/monocyte lineages and replating of stem and progenitor cells. Next, we performed single-cell RNA sequencing to identify specific cell populations that contribute to these pre-leukemic phenotypes. We discovered a subset of common myeloid progenitors that have heightened granulocyte/monocyte bias in AE9a mice. We also observed dysregulation of key hematopoietic transcription factor target gene networks, blocking cellular differentiation. Finally, we identified Sox4 activation as a potential contributor to stem cell self-renewal during the pre-leukemic stage.
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Affiliation(s)
- Ming Yan
- Moores Cancer Center, University of California San Diego, La Jolla, CA, USA
- Department of Pathology, University of California San Diego, La Jolla, CA, USA
| | - Mengdan Liu
- Moores Cancer Center, University of California San Diego, La Jolla, CA, USA
- Department of Pathology, University of California San Diego, La Jolla, CA, USA
- School of Biological Sciences, University of California San Diego, La Jolla, CA, USA
| | - Amanda G Davis
- Moores Cancer Center, University of California San Diego, La Jolla, CA, USA
- Department of Pathology, University of California San Diego, La Jolla, CA, USA
| | - Samuel A Stoner
- Moores Cancer Center, University of California San Diego, La Jolla, CA, USA
| | - Dong-Er Zhang
- Moores Cancer Center, University of California San Diego, La Jolla, CA, USA.
- Department of Pathology, University of California San Diego, La Jolla, CA, USA.
- School of Biological Sciences, University of California San Diego, La Jolla, CA, USA.
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2
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Weng W, Chen Y, Wang Y, Ying P, Guo X, Ruan J, Song H, Xu W, Zhang J, Xu X, Tang Y. A scoring system based on fusion genes to predict treatment outcomes of the non-acute promyelocytic leukemia pediatric acute myeloid leukemia. Front Med (Lausanne) 2023; 10:1258038. [PMID: 37942413 PMCID: PMC10628016 DOI: 10.3389/fmed.2023.1258038] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2023] [Accepted: 10/05/2023] [Indexed: 11/10/2023] Open
Abstract
Background Fusion genes are considered to be one of the major drivers behind cancer initiation and progression. Meanwhile, non-acute promyelocytic leukemia (APL) pediatric patients with acute myeloid leukemia (AML) in children had limited treatment efficacy. Hence, we developed and validated a simple clinical scoring system for predicting outcomes in non-APL pediatric patients with AML. Method A total of 184 non-APL pediatric patients with AML who were admitted to our hospital and an independent dataset (318 patients) from the TARGET database were included. Least absolute shrinkage and selection operation (LASSO) and Cox regression analysis were used to identify prognostic factors. Then, a nomogram score was developed to predict the 1, 3, and 5 years overall survival (OS) based on their clinical characteristics and fusion genes. The accuracy of the nomogram score was determined by calibration curves and receiver operating characteristic (ROC) curves. Additionally, an internal verification cohort was used to assess its applicability. Results Based on Cox and LASSO regression analyses, a nomogram score was constructed using clinical characteristics and OS-related fusion genes (CBFβ::MYH11, RUNX1::RUNX1T1, KMT2A::ELL, and KMT2A::MLLT10), yielded good calibration and concordance for predicting OS of non-APL pediatric patients with AML. Furthermore, patients with higher scores exhibited worse outcomes. The nomogram score also demonstrated good discrimination and calibration in the whole cohort and internal validation. Furthermore, artificial neural networks demonstrated that this nomogram score exhibits good predictive performance. Conclusion Our model based on the fusion gene is a prognostic biomarker for non-APL pediatric patients with AML. The nomogram score can provide personalized prognosis prediction, thereby benefiting clinical decision-making.
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Affiliation(s)
- Wenwen Weng
- Division/Center of Hematology-Oncology, Children’s Hospital of Zhejiang University School of Medicine, Hangzhou, China
- The Pediatric Leukemia Diagnostic and Therapeutic Technology Research Center of Zhejiang Province, National Clinical Research Center for Child Health Hangzhou, Hangzhou, China
| | - Yanfei Chen
- Division/Center of Hematology-Oncology, Children’s Hospital of Zhejiang University School of Medicine, Hangzhou, China
- The Pediatric Leukemia Diagnostic and Therapeutic Technology Research Center of Zhejiang Province, National Clinical Research Center for Child Health Hangzhou, Hangzhou, China
| | - Yuwen Wang
- Division/Center of Hematology-Oncology, Children’s Hospital of Zhejiang University School of Medicine, Hangzhou, China
- The Pediatric Leukemia Diagnostic and Therapeutic Technology Research Center of Zhejiang Province, National Clinical Research Center for Child Health Hangzhou, Hangzhou, China
| | - Peiting Ying
- Division/Center of Hematology-Oncology, Children’s Hospital of Zhejiang University School of Medicine, Hangzhou, China
- The Pediatric Leukemia Diagnostic and Therapeutic Technology Research Center of Zhejiang Province, National Clinical Research Center for Child Health Hangzhou, Hangzhou, China
| | - Xiaoping Guo
- Division/Center of Hematology-Oncology, Children’s Hospital of Zhejiang University School of Medicine, Hangzhou, China
- The Pediatric Leukemia Diagnostic and Therapeutic Technology Research Center of Zhejiang Province, National Clinical Research Center for Child Health Hangzhou, Hangzhou, China
| | - Jinfei Ruan
- Division/Center of Hematology-Oncology, Children’s Hospital of Zhejiang University School of Medicine, Hangzhou, China
- The Pediatric Leukemia Diagnostic and Therapeutic Technology Research Center of Zhejiang Province, National Clinical Research Center for Child Health Hangzhou, Hangzhou, China
| | - Hua Song
- Division/Center of Hematology-Oncology, Children’s Hospital of Zhejiang University School of Medicine, Hangzhou, China
- The Pediatric Leukemia Diagnostic and Therapeutic Technology Research Center of Zhejiang Province, National Clinical Research Center for Child Health Hangzhou, Hangzhou, China
| | - Weiqun Xu
- Division/Center of Hematology-Oncology, Children’s Hospital of Zhejiang University School of Medicine, Hangzhou, China
- The Pediatric Leukemia Diagnostic and Therapeutic Technology Research Center of Zhejiang Province, National Clinical Research Center for Child Health Hangzhou, Hangzhou, China
| | - Jingying Zhang
- Division/Center of Hematology-Oncology, Children’s Hospital of Zhejiang University School of Medicine, Hangzhou, China
- The Pediatric Leukemia Diagnostic and Therapeutic Technology Research Center of Zhejiang Province, National Clinical Research Center for Child Health Hangzhou, Hangzhou, China
| | - Xiaojun Xu
- Division/Center of Hematology-Oncology, Children’s Hospital of Zhejiang University School of Medicine, Hangzhou, China
- The Pediatric Leukemia Diagnostic and Therapeutic Technology Research Center of Zhejiang Province, National Clinical Research Center for Child Health Hangzhou, Hangzhou, China
| | - Yongmin Tang
- Division/Center of Hematology-Oncology, Children’s Hospital of Zhejiang University School of Medicine, Hangzhou, China
- The Pediatric Leukemia Diagnostic and Therapeutic Technology Research Center of Zhejiang Province, National Clinical Research Center for Child Health Hangzhou, Hangzhou, China
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3
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Rejeski K, Duque-Afonso J, Lübbert M. AML1/ETO and its function as a regulator of gene transcription via epigenetic mechanisms. Oncogene 2021; 40:5665-5676. [PMID: 34331016 PMCID: PMC8460439 DOI: 10.1038/s41388-021-01952-w] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2021] [Revised: 06/11/2021] [Accepted: 07/07/2021] [Indexed: 01/10/2023]
Abstract
The chromosomal translocation t(8;21) and the resulting oncofusion gene AML1/ETO have long served as a prototypical genetic lesion to model and understand leukemogenesis. In this review, we describe the wide-ranging role of AML1/ETO in AML leukemogenesis, with a particular focus on the aberrant epigenetic regulation of gene transcription driven by this AML-defining mutation. We begin by analyzing how structural changes secondary to distinct genomic breakpoints and splice changes, as well as posttranscriptional modifications, influence AML1/ETO protein function. Next, we characterize how AML1/ETO recruits chromatin-modifying enzymes to target genes and how the oncofusion protein alters chromatin marks, transcription factor binding, and gene expression. We explore the specific impact of these global changes in the epigenetic network facilitated by the AML1/ETO oncofusion on cellular processes and leukemic growth. Furthermore, we define the genetic landscape of AML1/ETO-positive AML, presenting the current literature concerning the incidence of cooperating mutations in genes such as KIT, FLT3, and NRAS. Finally, we outline how alterations in transcriptional regulation patterns create potential vulnerabilities that may be exploited by epigenetically active agents and other therapeutics.
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Affiliation(s)
- Kai Rejeski
- Department of Hematology, Oncology and Stem Cell Transplantation, University of Freiburg Medical Center, Freiburg, Germany.,Department of Hematology and Oncology, University Hospital of the LMU Munich, Munich, Germany.,German Cancer Consortium (DKTK) Freiburg Partner Site, German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Jesús Duque-Afonso
- Department of Hematology, Oncology and Stem Cell Transplantation, University of Freiburg Medical Center, Freiburg, Germany.,Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Michael Lübbert
- Department of Hematology, Oncology and Stem Cell Transplantation, University of Freiburg Medical Center, Freiburg, Germany. .,German Cancer Consortium (DKTK) Freiburg Partner Site, German Cancer Research Center (DKFZ), Heidelberg, Germany. .,Faculty of Medicine, University of Freiburg, Freiburg, Germany.
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4
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Neckles C, Sundara Rajan S, Caplen NJ. Fusion transcripts: Unexploited vulnerabilities in cancer? WILEY INTERDISCIPLINARY REVIEWS-RNA 2019; 11:e1562. [PMID: 31407506 PMCID: PMC6916338 DOI: 10.1002/wrna.1562] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/06/2019] [Revised: 07/05/2019] [Accepted: 07/08/2019] [Indexed: 12/12/2022]
Abstract
Gene fusions are an important class of mutations in several cancer types and include genomic rearrangements that fuse regulatory or coding elements from two different genes. Analysis of the genetics of cancers harboring fusion oncogenes and the proteins they encode have enhanced cancer diagnosis and in some cases patient treatment. However, the effect of the complex structure of fusion genes on the biogenesis of the resulting chimeric transcripts they express is not well studied. There are two potential RNA‐related vulnerabilities inherent to fusion‐driven cancers: (a) the processing of the fusion precursor messenger RNA (pre‐mRNA) to the mature mRNA and (b) the mature mRNA. In this study, we discuss the effects that the genetic organization of fusion oncogenes has on the generation of translatable mature RNAs and the diversity of fusion transcripts expressed in different cancer subtypes, which can fundamentally influence both tumorigenesis and treatment. We also discuss functional genomic approaches that can be utilized to identify proteins that mediate the processing of fusion pre‐mRNAs. Furthermore, we assert that an enhanced understanding of fusion transcript biogenesis and the diversity of the chimeric RNAs present in fusion‐driven cancers will increase the likelihood of successful application of RNA‐based therapies in this class of tumors. This article is categorized under:RNA Processing > RNA Editing and Modification RNA Processing > Splicing Regulation/Alternative Splicing RNA in Disease and Development > RNA in Disease
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Affiliation(s)
- Carla Neckles
- Functional Genetics Section, Genetics Branch, Center for Cancer Research, National Cancer Institute, National Institutes of Health, DHHS, Bethesda, Maryland
| | - Soumya Sundara Rajan
- Functional Genetics Section, Genetics Branch, Center for Cancer Research, National Cancer Institute, National Institutes of Health, DHHS, Bethesda, Maryland
| | - Natasha J Caplen
- Functional Genetics Section, Genetics Branch, Center for Cancer Research, National Cancer Institute, National Institutes of Health, DHHS, Bethesda, Maryland
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5
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Panagopoulos I, Torkildsen S, Gorunova L, Ulvmoen A, Tierens A, Zeller B, Heim S. RUNX1 truncation resulting from a cryptic and novel t(6;21)(q25;q22) chromosome translocation in acute myeloid leukemia: A case report. Oncol Rep 2016; 36:2481-2488. [PMID: 27667292 PMCID: PMC5055202 DOI: 10.3892/or.2016.5119] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2016] [Accepted: 08/12/2016] [Indexed: 12/28/2022] Open
Abstract
Fluorescence in situ hybridization examination of a pediatric AML patient whose bone marrow cells carried trisomy 4 and FLT3-ITD mutation, demonstrated that part of the RUNX1 probe had unexpectedly moved to chromosome band 6q25 indicating a cryptic t(6;21)(q25;q22) translocation. RNA sequencing showed fusion of exon 7 of RUNX1 with an intergenic sequence of 6q25 close to the MIR1202 locus, something that was verified by RT-PCR together with Sanger sequencing. The RUNX1 fusion transcript encodes a truncated protein containing the Runt homology domain responsible for both heterodimerization with CBFB and DNA binding, but lacking the proline-, serine-, and threonine-rich (PST) region which is the transcription activation domain at the C terminal end. Which genetic event (+4, FLT3-ITD, t(6;21)-RUNX1 truncation or other, undetected acquired changes) was more pathogenetically important in the present case of AML, remains unknown. The case illustrates that submicroscopic chromosomal rearrangements may accompany visible numerical changes and perhaps should be actively looked for whenever a single trisomy is found. An active search for them may provide both pathogenetic and prognostic novel information.
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Affiliation(s)
- Ioannis Panagopoulos
- Section for Cancer Cytogenetics, Institute for Cancer Genetics and Informatics, The Norwegian Radium Hospital, Oslo University Hospital, NO-0424 Oslo, Norway
| | - Synne Torkildsen
- Section for Cancer Cytogenetics, Institute for Cancer Genetics and Informatics, The Norwegian Radium Hospital, Oslo University Hospital, NO-0424 Oslo, Norway
| | - Ludmila Gorunova
- Section for Cancer Cytogenetics, Institute for Cancer Genetics and Informatics, The Norwegian Radium Hospital, Oslo University Hospital, NO-0424 Oslo, Norway
| | - Aina Ulvmoen
- Pediatric Medicine, Oslo University Hospital, NO-0424 Oslo, Norway
| | - Anne Tierens
- Laboratory Medicine Program, Department of Haematopathology, University Health Network, Toronto, Ontario M5G 2C4, Canada
| | - Bernward Zeller
- Pediatric Medicine, Oslo University Hospital, NO-0424 Oslo, Norway
| | - Sverre Heim
- Section for Cancer Cytogenetics, Institute for Cancer Genetics and Informatics, The Norwegian Radium Hospital, Oslo University Hospital, NO-0424 Oslo, Norway
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Grinev VV, Migas AA, Kirsanava AD, Mishkova OA, Siomava N, Ramanouskaya TV, Vaitsiankova AV, Ilyushonak IM, Nazarov PV, Vallar L, Aleinikova OV. Decoding of exon splicing patterns in the human RUNX1-RUNX1T1 fusion gene. Int J Biochem Cell Biol 2015; 68:48-58. [PMID: 26320575 DOI: 10.1016/j.biocel.2015.08.017] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2015] [Revised: 08/12/2015] [Accepted: 08/24/2015] [Indexed: 11/25/2022]
Abstract
The t(8;21) translocation is the most widespread genetic defect found in human acute myeloid leukemia. This translocation results in the RUNX1-RUNX1T1 fusion gene that produces a wide variety of alternative transcripts and influences the course of the disease. The rules of combinatorics and splicing of exons in the RUNX1-RUNX1T1 transcripts are not known. To address this issue, we developed an exon graph model of the fusion gene organization and evaluated its local exon combinatorics by the exon combinatorial index (ECI). Here we show that the local exon combinatorics of the RUNX1-RUNX1T1 gene follows a power-law behavior and (i) the vast majority of exons has a low ECI, (ii) only a small part is represented by "exons-hubs" of splicing with very high ECI values, and (iii) it is scale-free and very sensitive to targeted skipping of "exons-hubs". Stochasticity of the splicing machinery and preferred usage of exons in alternative splicing can explain such behavior of the system. Stochasticity may explain up to 12% of the ECI variance and results in a number of non-coding and unproductive transcripts that can be considered as a noise. Half-life of these transcripts is increased due to the deregulation of some key genes of the nonsense-mediated decay system in leukemia cells. On the other hand, preferred usage of exons may explain up to 75% of the ECI variability. Our analysis revealed a set of splicing-related cis-regulatory motifs that can explain "attractiveness" of exons in alternative splicing but only when they are considered together. Cis-regulatory motifs are guides for splicing trans-factors and we observed a leukemia-specific profile of expression of the splicing genes in t(8;21)-positive blasts. Altogether, our results show that alternative splicing of the RUNX1-RUNX1T1 transcripts follows strict rules and that the power-law component of the fusion gene organization confers a high flexibility to this process.
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Affiliation(s)
- Vasily V Grinev
- Department of Genetics, Faculty of Biology, Belarusian State University, Minsk, Belarus.
| | - Alexandr A Migas
- Laboratory of the Genetic Biotechnology, Department of Research, Belarusian Research Center for Pediatric Oncology, Hematology and Immunology, Minsk, Belarus
| | - Aksana D Kirsanava
- Department of Genetics, Faculty of Biology, Belarusian State University, Minsk, Belarus
| | - Olga A Mishkova
- Laboratory of the Genetic Biotechnology, Department of Research, Belarusian Research Center for Pediatric Oncology, Hematology and Immunology, Minsk, Belarus
| | - Natalia Siomava
- Department of Developmental Biology, University of Göttingen, Göttingen, Germany
| | | | - Alina V Vaitsiankova
- Department of Genetics, Faculty of Biology, Belarusian State University, Minsk, Belarus
| | - Ilia M Ilyushonak
- Department of Genetics, Faculty of Biology, Belarusian State University, Minsk, Belarus
| | - Petr V Nazarov
- Genomics Research Unit, Luxembourg Institute of Health, Luxembourg
| | - Laurent Vallar
- Genomics Research Unit, Luxembourg Institute of Health, Luxembourg
| | - Olga V Aleinikova
- Laboratory of the Genetic Biotechnology, Department of Research, Belarusian Research Center for Pediatric Oncology, Hematology and Immunology, Minsk, Belarus
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7
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Ghazaey Zidanloo S, Hosseinzaeh Colagar A. Geographic heterogeneity of the AML1-ETO fusion gene in Iranian patients with acute myeloid leukemia. Rep Biochem Mol Biol 2014; 3:7-13. [PMID: 26989731 PMCID: PMC4757083] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2014] [Accepted: 05/12/2014] [Indexed: 06/05/2023]
Abstract
BACKGROUND The human AML1 gene, located on chromosome 21, can be fused to the AML1- eight-twenty-one (ETO) oncoprotein on chromosome eight, resulting in a t(8;21)(q22;q22) translocation. Acute myeloid leukemia (AML) associated with this translocation is considered a distinct AML with a favorable prognosis. Due to the various incidences of the translocation, which is associated with geographic diversities, investigation of molecular epidemiology is important to increase the awareness of physicians and hematologists regarding the frequency this chromosomal aberration. METHODS The patients were classified according to the French-American-British classification into eight groups: M0-M7. Determination of the prevalence of the AML1-ETO fusion gene was accomplished by TaqMan real-time PCR. Bone marrow samples from 113 patients with newly-diagnosed, untreated AML -M1, -M2, and -M4, and 20 healthy controls admitted to the Ghaem Hospital in Mashhad, Iran were studied. RESULTS The AML1-ETO fusion gene was detected up 50% of the M2 subgroup and absent in the M1 and M4 subtypes and healthy controls. Comparison of the prevalence of the t(8;21) translocation with results of previous studies showed that it varies between countries. This result may be due to geographic or ethnic differences, or both. CONCLUSIONS The relatively high prevalence of the t(8;21) translocation in Iran was similar to that found in other Asian countries. It was closely associated with female gender, relatively young age, and FAB-M2 subtype. Its distribution varied considerably with geographic area. Therefore, further studies are needed to provide epidemiological data important for the establishment of optimal therapeutic strategies applicable to patients of each region.
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Affiliation(s)
- Saeedeh Ghazaey Zidanloo
- Department of Molecular and Cell Biology, Faculty of Basic Sciences, University of Mazandaran, Babolsar, CP: 47416-95447, Iran
| | - Abasalt Hosseinzaeh Colagar
- Department of Molecular and Cell Biology, Faculty of Basic Sciences, University of Mazandaran, Babolsar, CP: 47416-95447, Iran
- Nano and Biotechnology Research Group, Faculty of Basic Sciences, University of Mazandaran, Babolsar, Iran
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8
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Markova EN, Kantidze OL, Razin SV. Transcription of the AML1/ETO chimera is guided by the P2 promoter of the AML1 gene in the Kasumi-1 cell line. Gene 2012; 510:142-6. [PMID: 22995345 DOI: 10.1016/j.gene.2012.09.028] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2012] [Revised: 08/31/2012] [Accepted: 09/07/2012] [Indexed: 02/06/2023]
Abstract
Chromosomal translocation t (8;21)(q22;22) is one of the most frequent cytogenetic abnormalities found in acute myeloid leukaemia (AML). It generates the AML1/ETO fusion gene, which itself supports human haematopoietic stem cell self-renewal. However, the mechanism guiding transcription of this chimeric gene remains unclear. In our work, we attempted to shed light on this essential issue. We investigated the promoter from which transcription of the AML1/ETO gene is initiated and defined the three-dimensional structure of the whole rearranged locus.
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Affiliation(s)
- Elena N Markova
- Laboratory of Structural and Functional Organization of Chromosomes, Institute of Gene Biology RAS, 34/5 Vavilova Street, 119334 Moscow, Russia
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9
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Acute myeloid leukemia with the t(8;21) translocation: clinical consequences and biological implications. J Biomed Biotechnol 2011; 2011:104631. [PMID: 21629739 PMCID: PMC3100545 DOI: 10.1155/2011/104631] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2010] [Revised: 01/31/2011] [Accepted: 02/22/2011] [Indexed: 12/20/2022] Open
Abstract
The t(8;21) abnormality occurs in a minority of acute myeloid leukemia (AML) patients. The translocation results in an in-frame fusion of two genes, resulting in a fusion protein of one N-terminal domain from the AML1 gene and four C-terminal domains from the ETO gene. This protein has multiple effects on the regulation of the proliferation, the differentiation, and the viability of leukemic cells. The translocation can be detected as the only genetic abnormality or as part of more complex abnormalities. If t(8;21) is detected in a patient with bone marrow pathology, the diagnosis AML can be made based on this abnormality alone. t(8;21) is usually associated with a good prognosis. Whether the detection of the fusion gene can be used for evaluation of minimal residual disease and risk of leukemia relapse remains to be clarified. To conclude, detection of t(8;21) is essential for optimal handling of these patients as it has both diagnostic, prognostic, and therapeutic implications.
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10
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Grinev VV, Posrednik DV, Heidenreich O. Effective and specific control of aml1/eto gene expression in acute myeloid leukemia cells by lentivector-based RNA-interference. Mol Biol 2011. [DOI: 10.1134/s0026893311020087] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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11
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Giguère A, Hébert J. CLCA2, a novel RUNX1 partner gene in a therapy-related leukemia with t(1;21)(p22;q22). ACTA ACUST UNITED AC 2010; 202:94-100. [PMID: 20875871 DOI: 10.1016/j.cancergencyto.2010.07.116] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2010] [Revised: 06/16/2010] [Accepted: 07/02/2010] [Indexed: 11/17/2022]
Abstract
The RUNX1 gene is frequently rearranged in de novo and therapy-related leukemia. In the present study, we identified the CLCA2 gene as a novel fusion partner of RUNX1 in a case of therapy-related acute myeloid leukemia associated with t(1;21)(p22;q22). Reverse transcriptase-polymerase chain reaction analysis and sequencing revealed that the t(1;21) results in out-of-frame RUNX1-CLCA2 fusions. Alternative splicing generates at least six fusion transcripts, including a major transcript fusing RUNX1 exon 6 with CLCA2 exon 2. These out-of-frame fusions produce putative truncated RUNX1 isoforms retaining the DNA binding Runt domain but not the transcriptional regulatory domain of RUNX1. No mutations were found in the exons encoding the Runt and C-terminal domains of the nonrearranged RUNX1 gene. Similar to truncated RUNX1 isoforms previously described, these shortened products could act as dominant negative inhibitors of RUNX1-dependent transactivation. CLCA2 is a breast tumor suppressor gene that encodes a member of the calcium-activated chloride channel family and is involved for the first time in a chromosomal translocation. The RUNX1-CLCA2 fusion is another example of out-of-frame fusion generating truncated RUNX1 isoforms that represent a recurrent molecular mechanism in RUNX1-related leukemias.
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Affiliation(s)
- Amélie Giguère
- Quebec Leukemia Cell Bank and Hematology-Oncology Division, Maisonneuve-Rosemont Hospital, Montréal, Canada
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12
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Ommen HB, Ostergaard M, Yan M, Braendstrup K, Zhang DE, Hokland P. Persistent altered fusion transcript splicing identifies RUNX1-RUNX1T1+ AML patients likely to relapse. Eur J Haematol 2009; 84:128-32. [PMID: 19891700 DOI: 10.1111/j.1600-0609.2009.01371.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
In acute myeloid leukemia (AML) mouse models, the RUNX1-RUNX1T1 fusion protein has failed to produce leukemia by itself, but alternative splicing of exon 9a of the RUNX1-RUNX1T1 fusion transcript (FT) has recently been shown to enhance the leukemogenic potential. We have analyzed 138 diagnosis and follow-up samples from 13 RUNX1-RUNX1T1+ patients as well as diagnosis samples from 13 RUNX1-RUNX1T1- AML patients and 26 healthy donors. Levels of native RUNX1T1 mRNA were low in both healthy and RUNX1-RUNX1T1-negative AML samples. Likewise, the ratio between RUNX1T1 mRNA harboring exon 9a and lacking exon 9a was low and tightly regulated (0.017-0.11). In contrast, 11/13 RUNX1-RUNX1T1-positive AML patients displayed high and variable ratios of FT ranging from 0.05 to 0.46 (P < 0.001, Wilcoxon rank-sum test), indicating altered exon 9a splicing in these patients. Importantly, patients who remained in continuous complete remission displayed a faster disappearance of the RUNX1-RUNX1T1 exon 9a splice variant compared to patients bound to relapse (P = 0.02). In conclusion, alternative splicing seems to be part of the leukemogenic process in the majority of RUNX1-RUNX1T1-positive AML patients, and splice variant kinetics under cytoreduction may be a predictor for patients prone to relapse.
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Affiliation(s)
- Hans B Ommen
- Laboratory of Immunohematology, Department of Hematology, Aarhus University Hospital, Arhus, Denmark
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13
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RUNX1 regulates phosphoinositide 3-kinase/AKT pathway: role in chemotherapy sensitivity in acute megakaryocytic leukemia. Blood 2009; 114:2744-52. [PMID: 19638627 DOI: 10.1182/blood-2008-09-179812] [Citation(s) in RCA: 73] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
RUNX1 (AML1) encodes the core binding factor alpha subunit of a heterodimeric transcription factor complex which plays critical roles in normal hematopoiesis. Translocations or down-regulation of RUNX1 have been linked to favorable clinical outcomes in acute leukemias, suggesting that RUNX1 may also play critical roles in chemotherapy responses in acute leukemias; however, the molecular mechanisms remain unclear. The median level of RUNX1b transcripts in Down syndrome (DS) children with acute megakaryocytic leukemia (AMkL) were 4.4-fold (P < .001) lower than that in non-DS AMkL cases. Short hairpin RNA knockdown of RUNX1 in a non-DS AMkL cell line, Meg-01, resulted in significantly increased sensitivity to cytosine arabinoside, accompanied by significantly decreased expression of PIK3CD, which encodes the delta catalytic subunit of the survival kinase, phosphoinositide 3 (PI3)-kinase. Transcriptional regulation of PIK3CD by RUNX1 was further confirmed by chromatin immunoprecipitation and promoter reporter gene assays. Further, a PI3-kinase inhibitor, LY294002, and cytosine arabinoside synergized in antileukemia effects on Meg-01 and primary pediatric AMkL cells. Our results suggest that RUNX1 may play a critical role in chemotherapy response in AMkL by regulating the PI3-kinase/Akt pathway. Thus, the treatment of AMkL may be improved by integrating PI3-kinase or Akt inhibitors into the chemotherapy of this disease.
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Gustafson SA, Lin P, Chen SS, Chen L, Abruzzo LV, Luthra R, Medeiros LJ, Wang SA. Therapy-related acute myeloid leukemia with t(8;21) (q22;q22) shares many features with de novo acute myeloid leukemia with t(8;21)(q22;q22) but does not have a favorable outcome. Am J Clin Pathol 2009; 131:647-55. [PMID: 19369623 DOI: 10.1309/ajcp5ethdxo6ncgz] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
To determine if therapy-related acute myeloid leukemia (t-AML) with t(8;21)(q22;q22) [t-AML-t(8;21)] harbors similar characteristic clinicopathologic features as de novo AML-t(8;21) (q22;q22), we studied 13 cases of t-AML-t(8;21) and 38 adult cases of de novo AML-t(8;21) diagnosed and treated at our hospital (1995-2008). Of 13 t-AML-t(8;21) cases, 11 had previously received chemotherapy with or without radiation for malignant neoplasms and 2 received radiation alone. The median latency to t-AML onset was 37 months (range, 11-126 months). Compared with patients with de novo AML-t(8;21), patients with t-AML-t(8;21) were older (P = .001) and had a lower WBC count (P = .039), substantial morphologic dysplasia, and comparable CD19/CD56 expression. The AML1-ETO (RUNX1-RUNX1T1) fusion was demonstrated in all 10 cases assessed. Class I mutations analyzed included FLT3 (0/10 [0%]), RAS (0/10 [0%]), JAK2 V617 (0/11 [0%]), and KIT (4/11 [36%]). With a median follow-up of 13 months, 10 patients with t-AML-t(8;21) died; the overall survival was significantly inferior to that of patients with de novo AML-t(8;21) (19 months vs not reached; P = .002). These findings suggest that t-AML-t(8;21) shares many features with de novo AML-t(8;21)(q22;q22), but affected patients have a worse outcome.
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Affiliation(s)
- Steven A Gustafson
- Department of Hematopathology, The University of Texas M. D. Anderson Cancer Center, 1515 Holcombe Blvd, Houston, TX 77030, USA
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Zuber J, Radtke I, Pardee TS, Zhao Z, Rappaport AR, Luo W, McCurrach ME, Yang MM, Dolan ME, Kogan SC, Downing JR, Lowe SW. Mouse models of human AML accurately predict chemotherapy response. Genes Dev 2009; 23:877-89. [PMID: 19339691 DOI: 10.1101/gad.1771409] [Citation(s) in RCA: 212] [Impact Index Per Article: 14.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
The genetic heterogeneity of cancer influences the trajectory of tumor progression and may underlie clinical variation in therapy response. To model such heterogeneity, we produced genetically and pathologically accurate mouse models of common forms of human acute myeloid leukemia (AML) and developed methods to mimic standard induction chemotherapy and efficiently monitor therapy response. We see that murine AMLs harboring two common human AML genotypes show remarkably diverse responses to conventional therapy that mirror clinical experience. Specifically, murine leukemias expressing the AML1/ETO fusion oncoprotein, associated with a favorable prognosis in patients, show a dramatic response to induction chemotherapy owing to robust activation of the p53 tumor suppressor network. Conversely, murine leukemias expressing MLL fusion proteins, associated with a dismal prognosis in patients, are drug-resistant due to an attenuated p53 response. Our studies highlight the importance of genetic information in guiding the treatment of human AML, functionally establish the p53 network as a central determinant of chemotherapy response in AML, and demonstrate that genetically engineered mouse models of human cancer can accurately predict therapy response in patients.
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Affiliation(s)
- Johannes Zuber
- Cold Spring Harbor Laboratory, Cold Spring Harbor, New York 11724, USA
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