1
|
Suzuki K, Koyama D, Oka Y, Sato Y, Sekine R, Fukatsu M, Hayashi K, Takano M, Hashimoto Y, Ikezoe T. Myeloid sarcoma with plasmacytoid dendritic cell-like proliferation associated with IKZF1, ETV6 and DNMT3A mutations. Int J Hematol 2024:10.1007/s12185-024-03806-z. [PMID: 38861243 DOI: 10.1007/s12185-024-03806-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2024] [Revised: 05/30/2024] [Accepted: 06/04/2024] [Indexed: 06/12/2024]
Abstract
The classification of clonal plasmacytoid dendritic cell (pDC) proliferation associated with myeloid neoplasms remains a topic of ongoing debate. Although the fifth edition of the World Health Organization classification classifies clonal pDC proliferation into two categories, it is unclear whether this classification adequately captures the complexities of clonal pDC pathogenesis. We present a clinical case featuring myeloid sarcoma with pDC-like cells in cervical lymph nodes and bone marrow (BM). Analysis of biopsy specimens and BM aspirate revealed two distinct cellular populations expressing myeloid and pDC markers. One population exhibited myeloid leukemia and monocyte markers, including MPO, CD13, CD33, CD11b, and CD14, while the other manifested an immunophenotype reminiscent of pDCs, characterized by expression of CD56 and CD123. Additionally, whole exome sequencing and RNA sequencing of BM mononuclear cells were conducted to explore the pathophysiology of this rare malignancy, and unveiled pDC-like cell proliferation driven by IKZF1 and ETV6 mutations originating from clonal hematopoiesis initiated by a DNMT3A mutation. Notably, venetoclax-based therapy exhibited efficacy for achieving and sustaining complete remission. This case provides pivotal insights into the mechanistic aspects of pDC/pDC-like cell proliferation in myeloid sarcoma, offering valuable perspectives on therapeutic strategies.
Collapse
Affiliation(s)
- Kengo Suzuki
- Department of Hematology, Fukushima Medical University, Fukushima, 960-1295, Japan
| | - Daisuke Koyama
- Department of Hematology, Fukushima Medical University, Fukushima, 960-1295, Japan.
| | - Yuka Oka
- Department of Diagnostic Pathology, Fukushima Medical University, Fukushima, 960-1295, Japan
| | - Yuki Sato
- Department of Hematology, Fukushima Medical University, Fukushima, 960-1295, Japan
| | - Rei Sekine
- Department of Diagnostic Pathology, Fukushima Medical University, Fukushima, 960-1295, Japan
| | - Masahiko Fukatsu
- Department of Hematology, Fukushima Medical University, Fukushima, 960-1295, Japan
| | - Kiyohito Hayashi
- Department of Hematology, Fukushima Medical University, Fukushima, 960-1295, Japan
| | - Motoki Takano
- Department of Hematology, Fukushima Medical University, Fukushima, 960-1295, Japan
| | - Yuko Hashimoto
- Department of Diagnostic Pathology, Fukushima Medical University, Fukushima, 960-1295, Japan
| | - Takayuki Ikezoe
- Department of Hematology, Fukushima Medical University, Fukushima, 960-1295, Japan
| |
Collapse
|
2
|
Yamasaki T, Nishiyama A, Kurogi N, Nishimura K, Nishida S, Kurotaki D, Ban T, Ramilowski JA, Ozato K, Toyoda A, Tamura T. Physical and functional interaction among Irf8 enhancers during dendritic cell differentiation. Cell Rep 2024; 43:114107. [PMID: 38613785 DOI: 10.1016/j.celrep.2024.114107] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2023] [Revised: 02/28/2024] [Accepted: 03/28/2024] [Indexed: 04/15/2024] Open
Abstract
The production of type 1 conventional dendritic cells (cDC1s) requires high expression of the transcription factor IRF8. Three enhancers at the Irf8 3' region function in a differentiation stage-specific manner. However, whether and how these enhancers interact physically and functionally remains unclear. Here, we show that the Irf8 3' enhancers directly interact with each other and contact the Irf8 gene body during cDC1 differentiation. The +56 kb enhancer, which functions from multipotent progenitor stages, activates the other 3' enhancers through an IRF8-dependent transcription factor program, that is, in trans. Then, the +32 kb enhancer, which operates in cDC1-committed cells, reversely acts in cis on the other 3' enhancers to maintain the high expression of Irf8. Indeed, mice with compound heterozygous deletion of the +56 and +32 kb enhancers are unable to generate cDC1s. These results illustrate how multiple enhancers cooperate to induce a lineage-determining transcription factor gene during cell differentiation.
Collapse
Affiliation(s)
- Takaya Yamasaki
- Department of Immunology, Yokohama City University Graduate School of Medicine, Yokohama, Kanagawa, Japan
| | - Akira Nishiyama
- Department of Immunology, Yokohama City University Graduate School of Medicine, Yokohama, Kanagawa, Japan
| | - Nagomi Kurogi
- Department of Immunology, Yokohama City University Graduate School of Medicine, Yokohama, Kanagawa, Japan
| | - Koutarou Nishimura
- Department of Immunology, Yokohama City University Graduate School of Medicine, Yokohama, Kanagawa, Japan
| | - Shion Nishida
- Department of Immunology, Yokohama City University Graduate School of Medicine, Yokohama, Kanagawa, Japan; Laboratory of Stem Cell Biology, Department of Biosciences, Kitasato University School of Science, Sagamihara, Kanagawa, Japan
| | - Daisuke Kurotaki
- Laboratory of Chromatin Organization in Immune Cell Development, International Research Center for Medical Sciences, Kumamoto University, Kumamoto, Japan
| | - Tatsuma Ban
- Department of Immunology, Yokohama City University Graduate School of Medicine, Yokohama, Kanagawa, Japan
| | - Jordan A Ramilowski
- Advanced Medical Research Center, Yokohama City University, Yokohama, Kanagawa, Japan
| | - Keiko Ozato
- Division of Developmental Biology, National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, USA
| | - Atsushi Toyoda
- Comparative Genomics Laboratory, National Institute of Genetics, Mishima, Shizuoka, Japan; Advanced Genomics Center, National Institute of Genetics, Mishima, Shizuoka, Japan
| | - Tomohiko Tamura
- Department of Immunology, Yokohama City University Graduate School of Medicine, Yokohama, Kanagawa, Japan; Advanced Medical Research Center, Yokohama City University, Yokohama, Kanagawa, Japan.
| |
Collapse
|
3
|
Parriott G, Hegermiller E, Morman RE, Frank C, Saygin C, Stock W, Bartom ET, Kee BL. Loss of thymocyte competition underlies the tumor suppressive functions of the E2a transcription factor in T-ALL. Leukemia 2024; 38:491-501. [PMID: 38155245 DOI: 10.1038/s41375-023-02123-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2023] [Revised: 12/11/2023] [Accepted: 12/13/2023] [Indexed: 12/30/2023]
Abstract
T lymphocyte acute lymphoblastic leukemia (T-ALL) is frequently associated with increased expression of the E protein transcription factor inhibitors TAL1 and LYL1. In mouse models, ectopic expression of TAL1 or LYL1 in T cell progenitors, or inactivation of E2A, is sufficient to predispose mice to develop T-ALL. How E2A suppresses thymocyte transformation is currently unknown. Here, we show that early deletion of E2a, prior to the DN3 stage, was required for robust leukemogenesis and was associated with alterations in thymus cellularity, T cell differentiation, and gene expression in immature CD4+CD8+ thymocytes. Introduction of wild-type thymocytes into mice with early deletion of E2a prevented leukemogenesis, or delayed disease onset, and impacted the expression of multiple genes associated with transformation and genome instability. Our data indicate that E2A suppresses leukemogenesis by promoting T cell development and enforcing inter-thymocyte competition, a mechanism that is emerging as a safeguard against thymocyte transformation. These studies have implications for understanding how multiple essential regulators of T cell development suppress T-ALL and support the hypothesis that thymocyte competition suppresses leukemogenesis.
Collapse
Affiliation(s)
- Geoffrey Parriott
- Committee on Immunology, University of Chicago, Chicago, IL, 60637, USA
| | - Emma Hegermiller
- Department of Pathology, University of Chicago, Chicago, IL, 60637, USA
| | - Rosemary E Morman
- Committee on Immunology, University of Chicago, Chicago, IL, 60637, USA
- Department of Pathology, University of Chicago, Chicago, IL, 60637, USA
| | - Cameron Frank
- Department of Pathology, University of Chicago, Chicago, IL, 60637, USA
| | - Caner Saygin
- Section of Hematology/Oncology, Department of Medicine, University of Chicago, Chicago, IL, 60657, USA
| | - Wendy Stock
- Section of Hematology/Oncology, Department of Medicine, University of Chicago, Chicago, IL, 60657, USA
| | - Elizabeth T Bartom
- Department of Biochemistry and Molecular Genetics, Northwestern Feinberg School of Medicine, Chicago, IL, USA
| | - Barbara L Kee
- Committee on Immunology, University of Chicago, Chicago, IL, 60637, USA.
- Department of Pathology, University of Chicago, Chicago, IL, 60637, USA.
- Section of Hematology/Oncology, Department of Medicine, University of Chicago, Chicago, IL, 60657, USA.
- Department of Biochemistry and Molecular Genetics, Northwestern Feinberg School of Medicine, Chicago, IL, USA.
| |
Collapse
|
4
|
Melnick AF, Mullin C, Lin K, McCarter AC, Liang S, Liu YE, Wang Q, Jerome NA, Choe E, Kunnath N, Bodanapu G, Akter F, Magnuson B, Kumar S, Lombard DB, Muntean AG, Ljungman M, Sekiguchi J, Ryan RJH, Chiang MY. Cdc73 protects Notch-induced T-cell leukemia cells from DNA damage and mitochondrial stress. Blood 2023; 142:2159-2174. [PMID: 37616559 PMCID: PMC10733839 DOI: 10.1182/blood.2023020144] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2023] [Revised: 07/13/2023] [Accepted: 07/31/2023] [Indexed: 08/26/2023] Open
Abstract
ABSTRACT Activated Notch signaling is highly prevalent in T-cell acute lymphoblastic leukemia (T-ALL), but pan-Notch inhibitors showed excessive toxicity in clinical trials. To find alternative ways to target Notch signals, we investigated cell division cycle 73 (Cdc73), which is a Notch cofactor and key component of the RNA polymerase-associated transcriptional machinery, an emerging target in T-ALL. Although we confirmed previous work that CDC73 interacts with NOTCH1, we also found that the interaction in T-ALL was context-dependent and facilitated by the transcription factor ETS1. Using mouse models, we showed that Cdc73 is important for Notch-induced T-cell development and T-ALL maintenance. Mechanistically, chromatin and nascent gene expression profiling showed that Cdc73 intersects with Ets1 and Notch at chromatin within enhancers to activate expression of known T-ALL oncogenes through its enhancer functions. Cdc73 also intersects with these factors within promoters to activate transcription of genes that are important for DNA repair and oxidative phosphorylation through its gene body functions. Consistently, Cdc73 deletion induced DNA damage and apoptosis and impaired mitochondrial function. The CDC73-induced DNA repair expression program co-opted by NOTCH1 is more highly expressed in T-ALL than in any other cancer. These data suggest that Cdc73 might induce a gene expression program that was eventually intersected and hijacked by oncogenic Notch to augment proliferation and mitigate the genotoxic and metabolic stresses of elevated Notch signaling. Our report supports studying factors such as CDC73 that intersect with Notch to derive a basic scientific understanding on how to combat Notch-dependent cancers without directly targeting the Notch complex.
Collapse
Affiliation(s)
- Ashley F. Melnick
- Cellular and Molecular Biology Program, University of Michigan School of Medicine, Ann Arbor, MI
| | - Carea Mullin
- Division of Hematology-Oncology, Department of Internal Medicine, University of Michigan School of Medicine, Ann Arbor, MI
| | - Karena Lin
- Cellular and Molecular Biology Program, University of Michigan School of Medicine, Ann Arbor, MI
| | - Anna C. McCarter
- Cellular and Molecular Biology Program, University of Michigan School of Medicine, Ann Arbor, MI
- Department of Anesthesiology, Perioperative and Pain Medicine, Stanford University, Stanford, CA
| | - Shannon Liang
- Department of Anesthesiology, Perioperative and Pain Medicine, Stanford University, Stanford, CA
| | - Yiran E. Liu
- Cancer Biology Program, Stanford University, Stanford, CA
| | - Qing Wang
- Division of Hematology-Oncology, Department of Internal Medicine, University of Michigan School of Medicine, Ann Arbor, MI
| | - Nicole A. Jerome
- Cancer Biology Program, University of Michigan School of Medicine, Ann Arbor, MI
| | - Elizabeth Choe
- Department of Computational Medicine and Bioinformatics, University of Michigan, Ann Arbor, MI
| | - Nicholas Kunnath
- Center for Healthcare Outcomes and Policy, University of Michigan School of Medicine, Ann Arbor, MI
| | - Geethika Bodanapu
- School of Medicine, Boston University Chobanian & Avedisian School of Medicine, Boston, MA
| | - Fatema Akter
- Department of Anesthesiology, Perioperative and Pain Medicine, Stanford University, Stanford, CA
| | - Brian Magnuson
- Michigan Center for Translational Pathology, University of Michigan School of Medicine, Ann Arbor, MI
| | - Surinder Kumar
- Department of Pathology and Laboratory Medicine and Sylvester Comprehensive Cancer Center, Miller School of Medicine, University of Miami, Miami, FL
| | - David B. Lombard
- Department of Pathology and Laboratory Medicine and Sylvester Comprehensive Cancer Center, Miller School of Medicine, University of Miami, Miami, FL
| | - Andrew G. Muntean
- Cellular and Molecular Biology Program, University of Michigan School of Medicine, Ann Arbor, MI
- Department of Pathology, University of Michigan, Ann Arbor, MI
| | - Mats Ljungman
- Cellular and Molecular Biology Program, University of Michigan School of Medicine, Ann Arbor, MI
- Department of Radiology Oncology, University of Michigan School of Medicine, Ann Arbor, MI
| | - JoAnn Sekiguchi
- Cancer Biology Program, University of Michigan School of Medicine, Ann Arbor, MI
- Department of Human Genetics, University of Michigan School of Medicine, Ann Arbor, MI
| | - Russell J. H. Ryan
- Cellular and Molecular Biology Program, University of Michigan School of Medicine, Ann Arbor, MI
- Cancer Biology Program, University of Michigan School of Medicine, Ann Arbor, MI
- Department of Pathology, University of Michigan, Ann Arbor, MI
| | - Mark Y. Chiang
- Cellular and Molecular Biology Program, University of Michigan School of Medicine, Ann Arbor, MI
- Division of Hematology-Oncology, Department of Internal Medicine, University of Michigan School of Medicine, Ann Arbor, MI
- Cancer Biology Program, University of Michigan School of Medicine, Ann Arbor, MI
| |
Collapse
|
5
|
Hu Y, Salgado Figueroa D, Zhang Z, Veselits M, Bhattacharyya S, Kashiwagi M, Clark MR, Morgan BA, Ay F, Georgopoulos K. Lineage-specific 3D genome organization is assembled at multiple scales by IKAROS. Cell 2023; 186:5269-5289.e22. [PMID: 37995656 PMCID: PMC10895928 DOI: 10.1016/j.cell.2023.10.023] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2023] [Revised: 07/28/2023] [Accepted: 10/25/2023] [Indexed: 11/25/2023]
Abstract
A generic level of chromatin organization generated by the interplay between cohesin and CTCF suffices to limit promiscuous interactions between regulatory elements, but a lineage-specific chromatin assembly that supersedes these constraints is required to configure the genome to guide gene expression changes that drive faithful lineage progression. Loss-of-function approaches in B cell precursors show that IKAROS assembles interactions across megabase distances in preparation for lymphoid development. Interactions emanating from IKAROS-bound enhancers override CTCF-imposed boundaries to assemble lineage-specific regulatory units built on a backbone of smaller invariant topological domains. Gain of function in epithelial cells confirms IKAROS' ability to reconfigure chromatin architecture at multiple scales. Although the compaction of the Igκ locus required for genome editing represents a function of IKAROS unique to lymphocytes, the more general function to preconfigure the genome to support lineage-specific gene expression and suppress activation of extra-lineage genes provides a paradigm for lineage restriction.
Collapse
Affiliation(s)
- Yeguang Hu
- Cutaneous Biology Research Center, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA 02129, USA
| | - Daniela Salgado Figueroa
- Centers for Autoimmunity, Inflammation and Cancer Immunotherapy, La Jolla Institute for Immunology, La Jolla, CA 92037, USA; Bioinformatics and Systems Biology Program, La Jolla, CA, USA
| | - Zhihong Zhang
- Cutaneous Biology Research Center, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA 02129, USA
| | - Margaret Veselits
- Gwen Knapp Center for Lupus and Immunology Research, Section of Rheumatology, Department of Medicine, The University of Chicago, Chicago, IL 60637, USA
| | - Sourya Bhattacharyya
- Centers for Autoimmunity, Inflammation and Cancer Immunotherapy, La Jolla Institute for Immunology, La Jolla, CA 92037, USA
| | - Mariko Kashiwagi
- Cutaneous Biology Research Center, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA 02129, USA
| | - Marcus R Clark
- Gwen Knapp Center for Lupus and Immunology Research, Section of Rheumatology, Department of Medicine, The University of Chicago, Chicago, IL 60637, USA
| | - Bruce A Morgan
- Cutaneous Biology Research Center, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA 02129, USA
| | - Ferhat Ay
- Centers for Autoimmunity, Inflammation and Cancer Immunotherapy, La Jolla Institute for Immunology, La Jolla, CA 92037, USA; Bioinformatics and Systems Biology Program, La Jolla, CA, USA; Department of Pediatrics, University of California, San Diego, La Jolla, CA 92093, USA.
| | - Katia Georgopoulos
- Cutaneous Biology Research Center, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA 02129, USA.
| |
Collapse
|
6
|
Affar M, Bottardi S, Quansah N, Lemarié M, Ramón AC, Affar EB, Milot E. IKAROS: from chromatin organization to transcriptional elongation control. Cell Death Differ 2023:10.1038/s41418-023-01212-2. [PMID: 37620540 DOI: 10.1038/s41418-023-01212-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2023] [Revised: 07/26/2023] [Accepted: 08/14/2023] [Indexed: 08/26/2023] Open
Abstract
IKAROS is a master regulator of cell fate determination in lymphoid and other hematopoietic cells. This transcription factor orchestrates the association of epigenetic regulators with chromatin, ensuring the expression pattern of target genes in a developmental and lineage-specific manner. Disruption of IKAROS function has been associated with the development of acute lymphocytic leukemia, lymphoma, chronic myeloid leukemia and immune disorders. Paradoxically, while IKAROS has been shown to be a tumor suppressor, it has also been identified as a key therapeutic target in the treatment of various forms of hematological malignancies, including multiple myeloma. Indeed, targeted proteolysis of IKAROS is associated with decreased proliferation and increased death of malignant cells. Although the molecular mechanisms have not been elucidated, the expression levels of IKAROS are variable during hematopoiesis and could therefore be a key determinant in explaining how its absence can have seemingly opposite effects. Mechanistically, IKAROS collaborates with a variety of proteins and complexes controlling chromatin organization at gene regulatory regions, including the Nucleosome Remodeling and Deacetylase complex, and may facilitate transcriptional repression or activation of specific genes. Several transcriptional regulatory functions of IKAROS have been proposed. An emerging mechanism of action involves the ability of IKAROS to promote gene repression or activation through its interaction with the RNA polymerase II machinery, which influences pausing and productive transcription at specific genes. This control appears to be influenced by IKAROS expression levels and isoform production. In here, we summarize the current state of knowledge about the biological roles and mechanisms by which IKAROS regulates gene expression. We highlight the dynamic regulation of this factor by post-translational modifications. Finally, potential avenues to explain how IKAROS destruction may be favorable in the treatment of certain hematological malignancies are also explored.
Collapse
Affiliation(s)
- Malik Affar
- Faculty of Medicine, University of Montreal, Montréal, QC, Canada
- Maisonneuve-Rosemont Hospital Research Center, CIUSSS de l'Est-de-l'Île de Montréal, 5415 boulevard de l'Assomption, Montréal, QC, H1T 2M4, Canada
| | - Stefania Bottardi
- Maisonneuve-Rosemont Hospital Research Center, CIUSSS de l'Est-de-l'Île de Montréal, 5415 boulevard de l'Assomption, Montréal, QC, H1T 2M4, Canada
| | - Norreen Quansah
- Maisonneuve-Rosemont Hospital Research Center, CIUSSS de l'Est-de-l'Île de Montréal, 5415 boulevard de l'Assomption, Montréal, QC, H1T 2M4, Canada
| | - Maud Lemarié
- Faculty of Medicine, University of Montreal, Montréal, QC, Canada
- Maisonneuve-Rosemont Hospital Research Center, CIUSSS de l'Est-de-l'Île de Montréal, 5415 boulevard de l'Assomption, Montréal, QC, H1T 2M4, Canada
| | - Ailyn C Ramón
- Faculty of Medicine, University of Montreal, Montréal, QC, Canada
- Maisonneuve-Rosemont Hospital Research Center, CIUSSS de l'Est-de-l'Île de Montréal, 5415 boulevard de l'Assomption, Montréal, QC, H1T 2M4, Canada
| | - El Bachir Affar
- Faculty of Medicine, University of Montreal, Montréal, QC, Canada.
- Maisonneuve-Rosemont Hospital Research Center, CIUSSS de l'Est-de-l'Île de Montréal, 5415 boulevard de l'Assomption, Montréal, QC, H1T 2M4, Canada.
| | - Eric Milot
- Faculty of Medicine, University of Montreal, Montréal, QC, Canada.
- Maisonneuve-Rosemont Hospital Research Center, CIUSSS de l'Est-de-l'Île de Montréal, 5415 boulevard de l'Assomption, Montréal, QC, H1T 2M4, Canada.
| |
Collapse
|
7
|
Parriott G, Hegermiller E, Morman RE, Frank C, Saygin C, Stock W, Bartom ET, Kee BL. Loss of thymocyte competition underlies the tumor suppressive functions of the E2a transcription factor in T lymphocyte acute lymphoblastic leukemia. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.04.23.537993. [PMID: 37163059 PMCID: PMC10168235 DOI: 10.1101/2023.04.23.537993] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
T lymphocyte acute lymphoblastic leukemia (T-ALL) is frequently associated with increased expression of the E protein transcription factor inhibitors TAL1 and LYL1. In mouse models, ectopic expression of Tal1 or Lyl1 in T cell progenitors or inactivation of E2a, is sufficient to predispose mice to develop T-ALL. How E2a suppresses thymocyte transformation is currently unknown. Here, we show that early deletion of E2a , prior to the DN3 stage, was required for robust leukemogenesis and was associated with alterations in thymus cellularity, T cell differentiation, and gene expression in immature CD4+CD8+ thymocytes. Introduction of wild-type thymocytes into mice with early deletion of E2a prevented leukemogenesis, or delayed disease onset, and impacted the expression of multiple genes associated with transformation and genome instability. Our data indicate that E2a suppresses leukemogenesis by promoting T cell development and enforcing inter-thymocyte competition, a mechanism that is emerging as a safeguard against thymocyte transformation. These studies have implications for understanding how multiple essential regulators of T cell development suppress T-ALL and support the hypothesis that thymus cellularity is a determinant of leukemogenesis.
Collapse
|
8
|
Melnick A, Liang S, Liu Y, Wang Q, Dean N, Choe E, Kunnath N, Bodanapu G, Mullin C, Akter F, Lin K, Magnuson B, Kumar S, Lombard DB, Muntean AG, Ljungman M, Sekiguchi J, Ryan RJH, Chiang MY. Cdc73 protects Notch-induced T-cell leukemia cells from DNA damage and mitochondrial stress. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.01.22.525059. [PMID: 36711472 PMCID: PMC9882378 DOI: 10.1101/2023.01.22.525059] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Activated Notch signaling is highly prevalent in T-cell acute lymphoblastic leukemia (T-ALL) but pan-Notch inhibitors were toxic in clinical trials. To find alternative ways to target Notch signals, we investigated Cell division cycle 73 (Cdc73), which is a Notch cofactor and component of transcriptional machinery, a potential target in T-ALL. While we confirmed previous work that CDC73 interacts with NOTCH1, we also found that the interaction in T-ALL was context-dependent and facilitated by the lymphoid transcription factor ETS1. Using mouse models, we showed that Cdc73 is important for Notch-induced T-cell development and T-ALL maintenance. Mechanistically, Cdc73, Ets1, and Notch intersect chromatin at promoters and enhancers to activate oncogenes and genes that are important for DNA repair and oxidative phosphorylation. Consistently, Cdc73 deletion in T-ALL cells induced DNA damage and impaired mitochondrial function. Our data suggests that Cdc73 might promote a gene expression program that was eventually intersected by Notch to mitigate the genotoxic and metabolic stresses of elevated Notch signaling. We also provide mechanistic support for testing inhibitors of DNA repair, oxidative phosphorylation, and transcriptional machinery. Inhibiting pathways like Cdc73 that intersect with Notch at chromatin might constitute a strategy to weaken Notch signals without directly targeting the Notch complex.
Collapse
|
9
|
Yamashita M, Taniuchi I. Fine-tuning Notch1 by the stage-specific enhancer. Nat Immunol 2022; 23:1509-1511. [DOI: 10.1038/s41590-022-01341-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
|