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Differential Transcriptional Reprogramming by Wild Type and Lymphoma-Associated Mutant MYC Proteins as B-Cells Convert to a Lymphoma Phenotype. Cancers (Basel) 2021; 13:cancers13236093. [PMID: 34885204 PMCID: PMC8657136 DOI: 10.3390/cancers13236093] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2021] [Revised: 11/26/2021] [Accepted: 11/29/2021] [Indexed: 11/16/2022] Open
Abstract
The MYC transcription factor regulates a vast number of genes and is implicated in many human malignancies. In some hematological malignancies, MYC is frequently subject to missense mutations that enhance its transformation activity. Here, we use a novel murine cell system to (i) characterize the transcriptional effects of progressively increasing MYC levels as normal primary B-cells transform to lymphoma cells and (ii) determine how this gene regulation program is modified by lymphoma-associated MYC mutations (T58A and T58I) that enhance its transformation activity. Unlike many previous studies, the cell system exploits primary B-cells that are transduced to allow regulated MYC expression under circumstances where apoptosis and senescence pathways are abrogated by the over-expression of the Bcl-xL and BMI1 proteins. In such cells, transition from a normal to a lymphoma phenotype is directly dependent on the MYC expression level, without a requirement for secondary events that are normally required during MYC-driven oncogenic transformation. A generalized linear model approach allowed an integrated analysis of RNA sequencing data to identify regulated genes in relation to both progressively increasing MYC level and wild type or mutant status. Using this design, a total of 7569 regulated genes were identified, of which the majority (n = 7263) were regulated in response to progressively increased levels of wild type MYC, while a smaller number of genes (n = 917) were differentially regulated, compared to wild type MYC, in T58A MYC- and/or T58I MYC-expressing cells. Unlike most genes that are similarly regulated by both wild type and mutant MYC genes, the set of 917 genes did not significantly overlap with known lipopolysaccharide regulated genes, which represent genes regulated by MYC in normal B cells. The genes that were differently regulated in cells expressing mutant MYC proteins were significantly enriched in DNA replication and G2 phase to mitosis transition genes. Thus, mutants affecting MYC proteins may augment quantitative oncogenic effects on the expression of normal MYC-target genes with qualitative oncogenic effects, by which sets of cell cycle genes are abnormally targeted by MYC as B cells transition into lymphoma cells. The T58A and T58I mutations augment MYC-driven transformation by distinct mechanisms.
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Zhu Y, Lin B, Ding F, Ma F, Zhou X, Zong H, Feng G, Chen Q, Chen G, Lv X. Leonurine negatively modulates T cells activity by suppressing recombination activation gene protein 2 in pulmonary fibrosis. EUR J INFLAMM 2021. [DOI: 10.1177/20587392211035907] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Introduction The key transformed T cell transcription factor recombination activation gene protein 2 (RAG2) is regulated during inflammation to allow for the acquisition of effector T cells functions. The present study was designed to investigate whether stress signals elicited by leonurine (LEO) could lead to the degradation of RAG2 through v-akt murine thymoma viral oncogene homolog (AKT) signaling in lung fibrosis. Methods A total of 120 female mice were randomly divided into five groups (Group I–V): Normal group, bleomycin (BLM), BLM+LEO 50 mg/kg/d, BLM+LEO 100 mg/kg/d, and BLM+LEO 50 mg/kg/d+LY294002. Hematoxylin-eosin, Masson’s, and terminal deoxynucleotidyl transferase dUTP nick-end labeling staining were performed to observe the pathomorphological changes. The expression of CD3+, TGF-β, RAG2, and Bcl proteins was examined by immunodetection, while that of E-cadherin (ECAD), AKT, TGF-β1, alpha-actin-2, Bax, and RAG2 was detected by Western blot analysis. Results The level of T lymphocytes was reduced sharply in LEO-treated mice as compared to the other groups. The AKT signal was greatly inhibited in the BLM group and activated with LEO treatment on day 14. In addition, RAG2 was attenuated by LEO on day 14 and day 28. LY294002 could reverse the expression of AKT and RAG2 on day 28. Remarkably, the low dose of LEO has a greater protective efficacy as compared to the high-dose LEO group in terms of pulmonary fibrosis, T cell inactivation, and apoptosis in alveolar cells. Conclusion The results of the present study suggested that LEO has a protective effect on lung fibrosis with possible mechanisms of attenuating apoptosis and inflammation via the upregulation of the AKT signal in transformed T cells by suppressing the expression and activity of RAG2.
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Affiliation(s)
- Yongping Zhu
- Department of Cardiovascular Surgery, Fujian Medical University Attached Union Hospital, Fuzhou, Fujian, China
| | - Bixia Lin
- Department of Pharmacy, 1st Affiliated Hospital, Fujian Medical University, Fuzhou, Fujian, China
| | - Fadian Ding
- Department of Hepatopancreatobiliary Surgery and Institute of Abdominal Surgery, 1st Affiliated Hospital, Fujian Medical University, Fuzhou, Fujian, China
| | - Fenfen Ma
- Department of Pharmacy, Shanghai Pudong Hospital, Fudan University, Shanghai, China
| | - Xiaohui Zhou
- Department of Clinical Skill Training Center, Fujian Medical University, Fuzhou, Fujian, China
| | - Haiyang Zong
- Department of Orthopedic Surgery, The 920 Hospital of the Joint Logistic Support Force, Kunming, Yunnan, China
| | - Gao Feng
- Department of Pathology, 1st Affiliated Hospital, Fujian Medical University, Fuzhou, Fujian, China
| | - Qingquan Chen
- Department of Laboratory Medicine, Fujian Medical University, Fuzhou, China
| | - Gongping Chen
- Department of Respiratory and Critical Care Medicine, 1st Affiliated Hospital, Fujian Medical University, Fuzhou, Fujian, China
- Institute of Respiratory Disease, Fujian Medical University, Fuzhou, Fujian, China
| | - Xiaoting Lv
- Department of Respiratory and Critical Care Medicine, 1st Affiliated Hospital, Fujian Medical University, Fuzhou, Fujian, China
- Institute of Respiratory Disease, Fujian Medical University, Fuzhou, Fujian, China
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Redl E, Sheibani-Tezerji R, Cardona CDJ, Hamminger P, Timelthaler G, Hassler MR, Zrimšek M, Lagger S, Dillinger T, Hofbauer L, Draganić K, Tiefenbacher A, Kothmayer M, Dietz CH, Ramsahoye BH, Kenner L, Bock C, Seiser C, Ellmeier W, Schweikert G, Egger G. Requirement of DNMT1 to orchestrate epigenomic reprogramming for NPM-ALK-driven lymphomagenesis. Life Sci Alliance 2021; 4:e202000794. [PMID: 33310759 PMCID: PMC7768196 DOI: 10.26508/lsa.202000794] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2020] [Revised: 11/28/2020] [Accepted: 12/01/2020] [Indexed: 12/31/2022] Open
Abstract
Malignant transformation depends on genetic and epigenetic events that result in a burst of deregulated gene expression and chromatin changes. To dissect the sequence of events in this process, we used a T-cell-specific lymphoma model based on the human oncogenic nucleophosmin-anaplastic lymphoma kinase (NPM-ALK) translocation. We find that transformation of T cells shifts thymic cell populations to an undifferentiated immunophenotype, which occurs only after a period of latency, accompanied by induction of the MYC-NOTCH1 axis and deregulation of key epigenetic enzymes. We discover aberrant DNA methylation patterns, overlapping with regulatory regions, plus a high degree of epigenetic heterogeneity between individual tumors. In addition, ALK-positive tumors show a loss of associated methylation patterns of neighboring CpG sites. Notably, deletion of the maintenance DNA methyltransferase DNMT1 completely abrogates lymphomagenesis in this model, despite oncogenic signaling through NPM-ALK, suggesting that faithful maintenance of tumor-specific methylation through DNMT1 is essential for sustained proliferation and tumorigenesis.
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Affiliation(s)
- Elisa Redl
- Department of Pathology, Medical University of Vienna, Vienna, Austria
| | | | | | - Patricia Hamminger
- Division of Immunobiology, Institute of Immunology, Center for Pathophysiology, Infectiology and Immunology, Medical University of Vienna, Vienna, Austria
| | - Gerald Timelthaler
- Institute of Cancer Research, Medical University of Vienna, Vienna, Austria
| | - Melanie Rosalia Hassler
- Department of Pathology, Medical University of Vienna, Vienna, Austria
- Department of Urology, Medical University of Vienna, Vienna, Austria
| | - Maša Zrimšek
- Department of Pathology, Medical University of Vienna, Vienna, Austria
| | - Sabine Lagger
- Unit of Laboratory Animal Pathology, University of Veterinary Medicine Vienna, Vienna, Austria
| | - Thomas Dillinger
- Department of Pathology, Medical University of Vienna, Vienna, Austria
- Ludwig Boltzmann Institute Applied Diagnostics (LBI AD), Vienna, Austria
| | - Lorena Hofbauer
- Department of Pathology, Medical University of Vienna, Vienna, Austria
- Research Institute of Molecular Pathology (IMP), Vienna Biocenter (VBC), Vienna, Austria
| | - Kristina Draganić
- Department of Pathology, Medical University of Vienna, Vienna, Austria
| | - Andreas Tiefenbacher
- Department of Pathology, Medical University of Vienna, Vienna, Austria
- Ludwig Boltzmann Institute Applied Diagnostics (LBI AD), Vienna, Austria
| | - Michael Kothmayer
- Center for Anatomy and Cell Biology, Medical University of Vienna, Vienna, Austria
| | - Charles H Dietz
- CeMM Research Center for Molecular Medicine of the Austrian Academy of Sciences, Vienna, Austria
| | - Bernard H Ramsahoye
- Centre for Genetic and Experimental Medicine, Institute of Genomic and Molecular Medicine, University of Edinburgh, Edinburgh, UK
| | - Lukas Kenner
- Department of Pathology, Medical University of Vienna, Vienna, Austria
- Unit of Laboratory Animal Pathology, University of Veterinary Medicine Vienna, Vienna, Austria
- Christian Doppler Laboratory for Applied Metabolomics (CDL-AM), Medical University of Vienna, Vienna, Austria
- Center for Biomarker Research in Medicine (CBmed), CoreLab 2, Medical University of Vienna, Vienna, Austria
| | - Christoph Bock
- CeMM Research Center for Molecular Medicine of the Austrian Academy of Sciences, Vienna, Austria
- Department of Laboratory Medicine, Medical University of Vienna, Vienna, Austria
| | - Christian Seiser
- Center for Anatomy and Cell Biology, Medical University of Vienna, Vienna, Austria
| | - Wilfried Ellmeier
- Division of Immunobiology, Institute of Immunology, Center for Pathophysiology, Infectiology and Immunology, Medical University of Vienna, Vienna, Austria
| | - Gabriele Schweikert
- Max Planck Institute for Intelligent Systems, Tübingen, Germany
- Division of Computational Biology, School of Life Sciences, University of Dundee, Dundee, UK
| | - Gerda Egger
- Department of Pathology, Medical University of Vienna, Vienna, Austria
- Ludwig Boltzmann Institute Applied Diagnostics (LBI AD), Vienna, Austria
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Högstrand K, Lindvall JM, Sundblad A, Grandien A. Transformation of mature mouse B cells into malignant plasma cells in vitro via introduction of defined genetic elements. Eur J Immunol 2019; 49:454-461. [PMID: 30664244 DOI: 10.1002/eji.201847855] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2018] [Revised: 12/17/2018] [Accepted: 01/16/2019] [Indexed: 12/12/2022]
Abstract
An experimental system where defined alterations in gene function or gene expression levels in primary B cells would result in the development of transformed plasma cells in vitro would be useful in order to facilitate studies of the underlying molecular mechanisms of plasma cell malignancies. Here, such a system is described in which primary murine B cells rapidly become transformed into surface CD138+ , IgM-/low , CD19- IgM-secreting plasma cells as a result of expression of the transcription factors IRF4 and MYC together with simultaneous expression of BMI1, mutated p53 or silencing of p19Arf , and suppression of intrinsic apoptosis through expression of BCLXL. Analysis of gene expression patterns revealed that this combination of transforming genes resulted in expression of a number of genes previously associated with terminally differentiated B cells (plasma cells) and myeloma cells, whereas many genes associated with mature B cells and B-cell lymphomas were not expressed. Upon transplantation, the transformed cells preferentially localized to the bone marrow, presenting features of a plasma cell malignancy of the IgM isotype. The present findings may also be applicable in the development of novel methods for production of monoclonal antibodies.
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Affiliation(s)
- Kari Högstrand
- Center for Hematology and Regenerative Medicine, Department of Medicine, Karolinska Institutet, Karolinska University Hospital, Huddinge, Stockholm, Sweden
| | - Jessica M Lindvall
- National Bioinformatics Infrastructure Sweden (NBIS), Science for Life Laboratory, Department of Biochemistry and Biophysics, Stockholm University, Stockholm, Sweden
| | - Anne Sundblad
- Hematology Center, CMM, Bioclinicum, Department of Medicine, Karolinska Institutet, Karolinska University Hospital - Solna, Solna, Sweden
| | - Alf Grandien
- Center for Hematology and Regenerative Medicine, Department of Medicine, Karolinska Institutet, Karolinska University Hospital, Huddinge, Stockholm, Sweden
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Högstrand K, Grandien A. MYC-driven malignant transformation of mature murine B cells requires inhibition of both intrinsic apoptosis and p53 activity. Eur J Immunol 2018; 49:375-385. [PMID: 30281155 DOI: 10.1002/eji.201847585] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2018] [Revised: 08/02/2018] [Accepted: 09/28/2018] [Indexed: 12/14/2022]
Abstract
Increased expression of the oncogene MYC is a common feature of many B-cell malignancies, however MYC overexpression by itself is not sufficient for transformation, and additional genetic events are required, although the exact nature of these remains unknown. In patients and in transgenic mouse models, oncogenic transformation may occur in B cells at various differentiation stages interacting with complex microenvironments. B-cell oncogenesis often occurs after prolonged periods of time, making it difficult to accurately identify the genetic events required for transformation. An in vitro system, where malignant transformation of primary B cells could be analyzed, would facilitate the identification of genetic events required for transformation. Here, we describe such a system and show that primary murine B cells rapidly become transformed upon forced expression of MYC, in conjunction with simultaneous inhibition of the ARF/p53 axis via overexpression of BMI1, as well as through downregulation of p19ARF or expression of a dominant-negative p53 and suppression of intrinsic apoptosis through overexpression of BCLXL or MCL1. Established tumor cells remained addicted to expression of the lymphoma-inducing genes. In mice, transformed cells rapidly established fatal B-cell lymphomas. Our results suggest that transformation of normal mature B cells into lymphomas can occur as a consequence of three defined events.
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Affiliation(s)
- Kari Högstrand
- Center for Hematology and Regenerative Medicine, Karolinska Institutet, Department of Medicine, Karolinska University Hospital Huddinge, Stockholm, Sweden
| | - Alf Grandien
- Center for Hematology and Regenerative Medicine, Karolinska Institutet, Department of Medicine, Karolinska University Hospital Huddinge, Stockholm, Sweden
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