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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.
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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.
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2
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Hu AJ, Li W, Pathak A, Hu GF, Hou X, Farmer SR, Hu MG. CDK6 is essential for mesenchymal stem cell proliferation and adipocyte differentiation. Front Mol Biosci 2023; 10:1146047. [PMID: 37664186 PMCID: PMC10469316 DOI: 10.3389/fmolb.2023.1146047] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2023] [Accepted: 08/08/2023] [Indexed: 09/05/2023] Open
Abstract
Background: Overweight or obesity poses a significant risk of many obesity-related metabolic diseases. Among all the potential new therapies, stem cell-based treatments hold great promise for treating many obesity-related metabolic diseases. However, the mechanisms regulating adipocyte stem cells/progenitors (precursors) are unknown. The aim of this study is to investigate if CDK6 is required for mesenchymal stem cell proliferation and adipocyte differentiation. Methods: Cyclin-dependent kinase 6 (Cdk6) mouse models together with stem cells derived from stromal vascular fraction (SVF) or mouse embryonic fibroblasts (MEFs) of Cdk6 mutant mice were used to determine if CDK6 is required for mesenchymal stem cell proliferation and adipocyte differentiation. Results: We found that mice with a kinase inactive CDK6 mutants (K43M) had fewer precursor residents in the SVF of adult white adipose tissue (WAT). Stem cells from the SVF or MEFs of K43M mice had defects in proliferation and differentiation into the functional fat cells. In contrast, mice with a constitutively active kinase CDK6 mutant (R31C) had the opposite traits. Ablation of RUNX1 in both mature and precursor K43M cells, reversed the phenotypes. Conclusion: These results represent a novel role of CDK6 in regulating precursor numbers, proliferation, and differentiation, suggesting a potential pharmacological intervention for using CDK6 inhibitors in the treatment of obesity-related metabolic diseases.
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Affiliation(s)
- Alexander J. Hu
- Division of Hematology and Oncology, Tufts Medical Center, Department of Medicine, Boston, MA, United States
- Department of Surgery, Harvard Medical School, Brigham and Women’s Hospital, Boston, MA, United States
| | - Wei Li
- Division of Hematology and Oncology, Tufts Medical Center, Department of Medicine, Boston, MA, United States
- National Clinical Research Center of Cancer, Key Laboratory of Cancer Prevention and Therapy, Tianjin Medical University Cancer Institute and Hospital, Tianjin, China
| | - Apana Pathak
- Division of Hematology and Oncology, Tufts Medical Center, Department of Medicine, Boston, MA, United States
- Assay Research and Development Department, GRAIL LLC, Menlo Park, CA, United States
| | - Guo-Fu Hu
- Division of Hematology and Oncology, Tufts Medical Center, Department of Medicine, Boston, MA, United States
| | - Xiaoli Hou
- Division of Hematology and Oncology, Tufts Medical Center, Department of Medicine, Boston, MA, United States
- Center for Analysis and Testing, Zhejiang Chinese Medical University, Hangzhou, China
| | - Stephen R. Farmer
- Department of Biochemistry, Boston University School of Medicine, Boston, MA, United States
| | - Miaofen G. Hu
- Division of Hematology and Oncology, Tufts Medical Center, Department of Medicine, Boston, MA, United States
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3
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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.
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4
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Parriott G, Kee BL. E Protein Transcription Factors as Suppressors of T Lymphocyte Acute Lymphoblastic Leukemia. Front Immunol 2022; 13:885144. [PMID: 35514954 PMCID: PMC9065262 DOI: 10.3389/fimmu.2022.885144] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2022] [Accepted: 03/23/2022] [Indexed: 11/13/2022] Open
Abstract
T Lymphocyte Acute Lymphoblastic Leukemia (ALL) is an aggressive disease arising from transformation of T lymphocytes during their development. The mutation spectrum of T-ALL has revealed critical regulators of the growth and differentiation of normal and leukemic T lymphocytes. Approximately, 60% of T-ALLs show aberrant expression of the hematopoietic stem cell-associated helix-loop-helix transcription factors TAL1 and LYL1. TAL1 and LYL1 function in multiprotein complexes that regulate gene expression in T-ALL but they also antagonize the function of the E protein homodimers that are critical regulators of T cell development. Mice lacking E2A, or ectopically expressing TAL1, LYL1, or other inhibitors of E protein function in T cell progenitors, also succumb to an aggressive T-ALL-like disease highlighting that E proteins promote T cell development and suppress leukemogenesis. In this review, we discuss the role of E2A in T cell development and how alterations in E protein function underlie leukemogenesis. We focus on the role of TAL1 and LYL1 and the genes that are dysregulated in E2a-/- T cell progenitors that contribute to human T-ALL. These studies reveal novel mechanisms of transformation and provide insights into potential therapeutic targets for intervention in this disease.
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Affiliation(s)
- Geoffrey Parriott
- Committee on Immunology, University of Chicago, Chicago, IL, United States
| | - Barbara L Kee
- Committee on Immunology, University of Chicago, Chicago, IL, United States.,Committee on Cancer Biology, University of Chicago, Chicago, IL, United States.,Department of Pathology, University of Chicago, Chicago, IL, United States
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5
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Veiga DFT, Tremblay M, Gerby B, Herblot S, Haman A, Gendron P, Lemieux S, Zúñiga-Pflücker JC, Hébert J, Cohen JP, Hoang T. Monoallelic Heb/Tcf12 Deletion Reduces the Requirement for NOTCH1 Hyperactivation in T-Cell Acute Lymphoblastic Leukemia. Front Immunol 2022; 13:867443. [PMID: 35401501 PMCID: PMC8987207 DOI: 10.3389/fimmu.2022.867443] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2022] [Accepted: 02/28/2022] [Indexed: 12/21/2022] Open
Abstract
Early T-cell development is precisely controlled by E proteins, that indistinguishably include HEB/TCF12 and E2A/TCF3 transcription factors, together with NOTCH1 and pre-T cell receptor (TCR) signalling. Importantly, perturbations of early T-cell regulatory networks are implicated in leukemogenesis. NOTCH1 gain of function mutations invariably lead to T-cell acute lymphoblastic leukemia (T-ALL), whereas inhibition of E proteins accelerates leukemogenesis. Thus, NOTCH1, pre-TCR, E2A and HEB functions are intertwined, but how these pathways contribute individually or synergistically to leukemogenesis remain to be documented. To directly address these questions, we leveraged Cd3e-deficient mice in which pre-TCR signaling and progression through β-selection is abrogated to dissect and decouple the roles of pre-TCR, NOTCH1, E2A and HEB in SCL/TAL1-induced T-ALL, via the use of Notch1 gain of function transgenic (Notch1ICtg) and Tcf12+/- or Tcf3+/- heterozygote mice. As a result, we now provide evidence that both HEB and E2A restrain cell proliferation at the β-selection checkpoint while the clonal expansion of SCL-LMO1-induced pre-leukemic stem cells in T-ALL is uniquely dependent on Tcf12 gene dosage. At the molecular level, HEB protein levels are decreased via proteasomal degradation at the leukemic stage, pointing to a reversible loss of function mechanism. Moreover, in SCL-LMO1-induced T-ALL, loss of one Tcf12 allele is sufficient to bypass pre-TCR signaling which is required for Notch1 gain of function mutations and for progression to T-ALL. In contrast, Tcf12 monoallelic deletion does not accelerate Notch1IC-induced T-ALL, indicating that Tcf12 and Notch1 operate in the same pathway. Finally, we identify a tumor suppressor gene set downstream of HEB, exhibiting significantly lower expression levels in pediatric T-ALL compared to B-ALL and brain cancer samples, the three most frequent pediatric cancers. In summary, our results indicate a tumor suppressor function of HEB/TCF12 in T-ALL to mitigate cell proliferation controlled by NOTCH1 in pre-leukemic stem cells and prevent NOTCH1-driven progression to T-ALL.
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Affiliation(s)
- Diogo F. T. Veiga
- Department of Pharmacology and Physiology, Université de Montréal, Institute for Research in Immunology and Cancer, QC, Canada
- Department of Translational Medicine, School of Medical Sciences, University of Campinas, Campinas, Brazil
| | - Mathieu Tremblay
- Department of Pharmacology and Physiology, Université de Montréal, Institute for Research in Immunology and Cancer, QC, Canada
| | - Bastien Gerby
- Department of Pharmacology and Physiology, Université de Montréal, Institute for Research in Immunology and Cancer, QC, Canada
- Centre de Recherches en Cancérologie de Toulouse (CRCT), Université de Toulouse, Institut National de la Santé et de la Recherche Médicale (INSERM), UMR-1037, Université Toulouse III Paul Sabatier (UPS), Toulouse, France
| | - Sabine Herblot
- Department of Pharmacology and Physiology, Université de Montréal, Institute for Research in Immunology and Cancer, QC, Canada
- Unité de recherche en hémato-oncologie Charles-Bruneau, Centre de Recherche du CHU Sainte-Justine, Montréal, Canada
| | - André Haman
- Department of Pharmacology and Physiology, Université de Montréal, Institute for Research in Immunology and Cancer, QC, Canada
| | - Patrick Gendron
- Department of Pharmacology and Physiology, Université de Montréal, Institute for Research in Immunology and Cancer, QC, Canada
| | - Sébastien Lemieux
- Department of Pharmacology and Physiology, Université de Montréal, Institute for Research in Immunology and Cancer, QC, Canada
- Department of Biochemistry and Molecular Medicine, Institute for Research in Immunology and Cancer, Université de Montréal, Montréal, QC, Canada
| | | | - Josée Hébert
- Department of Pharmacology and Physiology, Université de Montréal, Institute for Research in Immunology and Cancer, QC, Canada
- Institut universitaire d’hémato-oncologie et de thérapie cellulaire, Hôpital Maisonneuve-Rosemont, Montréal, QC, Canada
- Quebec Leukemia Cell Bank, Centre de recherche de l’Hôpital Maisonneuve-Rosemont, Montréal, QC, Canada
- Department of Medicine, Université de Montréal, Montréal, QC, Canada
| | - Joseph Paul Cohen
- Department of Computer Science and Operations Research, Université de Montréal, Montreal, QC, Canada
- Université de Montréal, Montreal, QC, Canada
| | - Trang Hoang
- Department of Pharmacology and Physiology, Université de Montréal, Institute for Research in Immunology and Cancer, QC, Canada
- *Correspondence: Trang Hoang,
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6
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Carr T, McGregor S, Dias S, Verykokakis M, Le Beau MM, Xue HH, Sigvardsson M, Bartom ET, Kee BL. Oncogenic and Tumor Suppressor Functions for Lymphoid Enhancer Factor 1 in E2a-/- T Acute Lymphoblastic Leukemia. Front Immunol 2022; 13:845488. [PMID: 35371057 PMCID: PMC8971981 DOI: 10.3389/fimmu.2022.845488] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2021] [Accepted: 02/23/2022] [Indexed: 11/15/2022] Open
Abstract
T lymphocyte acute lymphoblastic leukemia (T-ALL) is a heterogeneous disease affecting T cells at multiple stages of their development and is characterized by frequent genomic alterations. The transcription factor LEF1 is inactivated through mutation in a subset of T-ALL cases but elevated LEF1 expression and activating mutations have also been identified in this disease. Here we show, in a murine model of T-ALL arising due to E2a inactivation, that the developmental timing of Lef1 mutation impacts its ability to function as a cooperative tumor suppressor or oncogene. T cell transformation in the presence of LEF1 allows leukemic cells to become addicted to its presence. In contrast, deletion prior to transformation both accelerates leukemogenesis and results in leukemic cells with altered expression of genes controlling receptor-signaling pathways. Our data demonstrate that the developmental timing of Lef1 mutations impact its apparent oncogenic or tumor suppressive characteristics and demonstrate the utility of mouse models for understanding the cooperation and consequence of mutational order in leukemogenesis.
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Affiliation(s)
- Tiffany Carr
- Committee on Immunology, The University of Chicago, Chicago, IL, United States
| | - Stephanie McGregor
- Committee on Cancer Biology, The University of Chicago, Chicago, IL, United States
| | - Sheila Dias
- Department of Pathology, The University of Chicago, Chicago, Chicago, IL, United States
| | - Mihalis Verykokakis
- Department of Pathology, The University of Chicago, Chicago, Chicago, IL, United States
| | - Michelle M. Le Beau
- Department of Medicine, Section of Hematology/Oncology, The University of Chicago, Chicago, IL, United States
| | - Hai-Hui Xue
- Center for Discovery and Innovation, Hackensack University Medical Center, Nutley, NJ, United States
| | | | - Elizabeth T. Bartom
- Department of Biochemistry and Molecular Genetics, Northwestern University, Chicago, IL, United States
| | - Barbara L. Kee
- Committee on Immunology, The University of Chicago, Chicago, IL, United States
- Committee on Cancer Biology, The University of Chicago, Chicago, IL, United States
- Department of Pathology, The University of Chicago, Chicago, Chicago, IL, United States
- *Correspondence: Barbara L. Kee,
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7
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Paradoxical role of Id proteins in regulating tumorigenic potential of lymphoid cells. Front Med 2018; 12:374-386. [PMID: 30043222 DOI: 10.1007/s11684-018-0652-x] [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: 03/10/2018] [Accepted: 06/26/2018] [Indexed: 12/11/2022]
Abstract
A family of transcription factors known as Id proteins, or inhibitor of DNA binding and differentiation, is capable of regulating cell proliferation, survival and differentiation, and is often upregulated in multiple types of tumors. Due to their ability to promote self-renewal, Id proteins have been considered as oncogenes, and potential therapeutic targets in cancer models. On the contrary, certain Id proteins are reported to act as tumor suppressors in the development of Burkitt's lymphoma in humans, and hepatosplenic and innate-like T cell lymphomas in mice. The contexts and mechanisms by which Id proteins can serve in such contradictory roles to determine tumor outcomes are still not well understood. In this review, we explore the roles of Id proteins in lymphocyte development and tumorigenesis, particularly with respect to inhibition of their canonical DNA binding partners known as E proteins. Transcriptional regulation by E proteins, and their antagonism by Id proteins, act as gatekeepers to ensure appropriate lymphocyte development at key checkpoints. We re-examine the derailment of these regulatory mechanisms in lymphocytes that facilitate tumor development. These mechanistic insights can allow better appreciation of the context-dependent roles of Id proteins in cancers and improve considerations for therapy.
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8
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Uddin S, Bhat AA, Krishnankutty R, Mir F, Kulinski M, Mohammad RM. Involvement of F-BOX proteins in progression and development of human malignancies. Semin Cancer Biol 2016; 36:18-32. [PMID: 26410033 DOI: 10.1016/j.semcancer.2015.09.008] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2015] [Revised: 09/15/2015] [Accepted: 09/15/2015] [Indexed: 12/13/2022]
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9
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Krishnamoorthy V, Carr T, de Pooter RF, Emanuelle AO, Akinola EO, Gounari F, Kee BL. Repression of Ccr9 transcription in mouse T lymphocyte progenitors by the Notch signaling pathway. THE JOURNAL OF IMMUNOLOGY 2015; 194:3191-200. [PMID: 25710912 DOI: 10.4049/jimmunol.1402443] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
The chemokine receptor CCR9 controls the immigration of multipotent hematopoietic progenitor cells into the thymus to sustain T cell development. Postimmigration, thymocytes downregulate CCR9 and migrate toward the subcapsular zone where they recombine their TCR β-chain and γ-chain gene loci. CCR9 is subsequently upregulated and participates in the localization of thymocytes during their selection for self-tolerant receptor specificities. Although the dynamic regulation of CCR9 is essential for early T cell development, the mechanisms controlling CCR9 expression have not been determined. In this article, we show that key regulators of T cell development, Notch1 and the E protein transcription factors E2A and HEB, coordinately control the expression of Ccr9. E2A and HEB bind at two putative enhancers upstream of Ccr9 and positively regulate CCR9 expression at multiple stages of T cell development. In contrast, the canonical Notch signaling pathway prevents the recruitment of p300 to the putative Ccr9 enhancers, resulting in decreased acetylation of histone H3 and a failure to recruit RNA polymerase II to the Ccr9 promoter. Although Notch signaling modestly modulates the binding of E proteins to one of the two Ccr9 enhancers, we found that Notch signaling represses Ccr9 in T cell lymphoma lines in which Ccr9 transcription is independent of E protein function. Our data support the hypothesis that activation of Notch1 has a dominant-negative effect on Ccr9 transcription and that Notch1 and E proteins control the dynamic expression of Ccr9 during T cell development.
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Affiliation(s)
- Veena Krishnamoorthy
- Committee on Molecular Pathogenesis and Molecular Medicine, The University of Chicago, Chicago, IL 60637
| | - Tiffany Carr
- Committee on Immunology, The University of Chicago, Chicago, IL 60637
| | - Renee F de Pooter
- Committee on Immunology, The University of Chicago, Chicago, IL 60637
| | | | | | - Fotini Gounari
- Committee on Immunology, The University of Chicago, Chicago, IL 60637; Section of Rheumatology, Department of Medicine, The University of Chicago, Chicago, IL 60637; and
| | - Barbara L Kee
- Committee on Molecular Pathogenesis and Molecular Medicine, The University of Chicago, Chicago, IL 60637; Committee on Immunology, The University of Chicago, Chicago, IL 60637; Department of Pathology, The University of Chicago, Chicago, IL 60637
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10
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Guo H, Lu Y, Wang J, Liu X, Keller ET, Liu Q, Zhou Q, Zhang J. Targeting the Notch signaling pathway in cancer therapeutics. Thorac Cancer 2014; 5:473-86. [PMID: 26767041 DOI: 10.1111/1759-7714.12143] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2014] [Accepted: 05/18/2014] [Indexed: 12/11/2022] Open
Abstract
Despite advances in surgery, imaging, chemotherapy, and radiotherapy, the poor overall cancer-related death rate remains unacceptable. Novel therapeutic strategies are desperately needed. Nowadays, targeted therapy has become the most promising therapy and a welcome asset to the cancer therapeutic arena. There is a large body of evidence demonstrating that the Notch signaling pathway is critically involved in the pathobiology of a variety of malignancies. In this review, we provide an overview of emerging data, highlight the mechanism of the Notch signaling pathway in the development of a wide range of cancers, and summarize recent progress in therapeutic targeting of the Notch signaling pathway.
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Affiliation(s)
- Huajiao Guo
- Key Laboratory of Longevity and Aging-Related Diseases, Ministry of Education Nanning, China; Center for Translational Medicine, Guangxi Medical University Nanning, China
| | - Yi Lu
- Key Laboratory of Longevity and Aging-Related Diseases, Ministry of Education Nanning, China; Center for Translational Medicine, Guangxi Medical University Nanning, China
| | - Jianhua Wang
- Department of Biochemistry and Molecular & Cell Biology, Key Laboratory of Cell Differentiation and Apoptosis, Ministry of Education Shanghai, China; Institute of Medical Science, Shanghai Jiao Tong University School of Medicine Shanghai, China
| | - Xia Liu
- Key Laboratory of Longevity and Aging-Related Diseases, Ministry of Education Nanning, China; Center for Translational Medicine, Guangxi Medical University Nanning, China
| | - Evan T Keller
- Department of Urology and Pathology, School of Medicine, University of Michigan Ann Arbor, Michigan, USA
| | - Qian Liu
- Tianjin Key Laboratory of Lung Cancer Metastasis and Tumor Microenvironment, Tianjin Lung Cancer Institute, Tianjin Medical University General Hospital Tianjin, China
| | - Qinghua Zhou
- Tianjin Key Laboratory of Lung Cancer Metastasis and Tumor Microenvironment, Tianjin Lung Cancer Institute, Tianjin Medical University General Hospital Tianjin, China
| | - Jian Zhang
- Key Laboratory of Longevity and Aging-Related Diseases, Ministry of Education Nanning, China; Center for Translational Medicine, Guangxi Medical University Nanning, China; Department of Urology and Pathology, School of Medicine, University of Michigan Ann Arbor, Michigan, USA
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11
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Young DJ, Stoddart A, Nakitandwe J, Chen SC, Qian Z, Downing JR, Le Beau MM. Knockdown of Hnrnpa0, a del(5q) gene, alters myeloid cell fate in murine cells through regulation of AU-rich transcripts. Haematologica 2014; 99:1032-40. [PMID: 24532040 DOI: 10.3324/haematol.2013.098657] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
The control of mRNA stability plays a central role in orchestrating gene-regulatory networks in hematopoietic cell growth, differentiation and tumorigenesis. HNRNPA0, which encodes an RNA-binding protein shown to regulate transcript stability via binding to the AU-rich elements of mRNAs, is located within the commonly deleted segment of 5q31.2 in myeloid neoplasms with a del(5q), and is expressed at haploinsufficient levels in these patients. We show that HNRNPA0 is normally highly expressed in hematopoietic stem cells and exhibits dynamic changes in expression during the course of differentiation. To model HNRNPA0 haploinsufficiency, we used RNAi interference in primary murine cells and an experimental cell system, and found that reduced Hnrnpa0 expression leads to a shift from monocytic towards granulocytic differentiation. Microarray-based global expression profiling revealed that Hnrnpa0 knockdown disproportionally impacts AU-rich containing transcripts and alters expression of myeloid specification genes. In therapy-related myeloid neoplasms with a del(5q), AU-rich containing mRNAs are enriched in transcripts that encode proteins associated with increased growth and proliferation. Our findings implicate haploinsufficiency of HNRNPA0 as one of the key initiating mutations in the pathogenesis of myeloid neoplasms with a del(5q), and suggest that therapies that target AU-rich elements warrant consideration in efforts to develop new mechanism-based treatment strategies.
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Affiliation(s)
- David J Young
- Department of Pediatrics, Division of Oncology, Johns Hopkins University, Baltimora, MD
| | - Angela Stoddart
- Department of Medicine and the Comprehensive Cancer Center, University of Chicago, IL
| | - Joy Nakitandwe
- St. Jude Children's Research Hospital, Memphis, Tennessee
| | | | - Zhijian Qian
- University of Illinois Cancer Center, Chicago, IL, USA
| | | | - Michelle M Le Beau
- Department of Medicine and the Comprehensive Cancer Center, University of Chicago, IL
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12
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Zhang Y, Hua C, Cheng H, Wang W, Hao S, Xu J, Wang X, Gao Y, Zhu X, Cheng T, Yuan W. Distinct sensitivity of CD8+ CD4- and CD8+ CD4+ leukemic cell subpopulations to cyclophosphamide and rapamycin in Notch1-induced T-ALL mouse model. Leuk Res 2013; 37:1592-601. [PMID: 24090996 DOI: 10.1016/j.leukres.2013.09.007] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2013] [Revised: 07/01/2013] [Accepted: 09/09/2013] [Indexed: 01/13/2023]
Abstract
The Notch1 signaling pathway plays an essential role in cell growth and differentiation. Over-expression of the intracellular Notch1 domain (ICN1) in murine hematopoietic cells is able to induce robust T-cell acute lymphoblastic leukemia (T-ALL) in mice. Here we explored the drug sensitivity of T-ALL cells in two subpopulations of CD8(+)CD4(+) and CD8(+)CD4(-) cells in Notch1-induced T-ALL mice. We found that Notch1 induced T-ALL cells could be decreased by chemotherapeutic drug cyclophosphamide (CTX). CD8(+)CD4(-) T-ALL cells were more sensitive to CTX treatment than CD8(+)CD4(+) T-ALL cells. The percentage of apoptotic cells induced by CTX treatment was higher in CD8(+)CD4(-) T-ALL cells. T-ALL cells were also inhibited by inhibitor of mTORC1 rapamycin. CD8(+)CD4(+) T-ALL cells were more susceptible to rapamycin treatment than CD8(+)CD4(-) T-ALL cells. Rapamycin treatment selectively arrested more CD8(+)CD4(+) T-ALL cells at G0 phase of cell cycle. A combination of the two drugs significantly improved overall survival of T-ALL bearing mice when compared with CTX or rapamycin alone. These results indicated that CD8(+)CD4(+) and CD8(+)CD4(-) leukemia cell populations had distinct drug sensitivity.
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Affiliation(s)
- Yingchi Zhang
- State Key Laboratory of Experimental Hematology, Institute of Hematology and Blood Diseases Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Tianjin 300020, China; Center for Stem Cell Medicine, Chinese Academy of Medical Sciences, Beijing 100730, China
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13
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Smeets MFMA, Chan AC, Dagger S, Bradley CK, Wei A, Izon DJ. Fli-1 overexpression in hematopoietic progenitors deregulates T cell development and induces pre-T cell lymphoblastic leukaemia/lymphoma. PLoS One 2013; 8:e62346. [PMID: 23667468 PMCID: PMC3646842 DOI: 10.1371/journal.pone.0062346] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2012] [Accepted: 03/20/2013] [Indexed: 12/28/2022] Open
Abstract
The Ets transcription factor Fli-1 is preferentially expressed in hematopoietic tissues and cells, including immature T cells, but the role of Fli-1 in T cell development has not been closely examined. To address this we retrovirally overexpressed Fli-1 in various in vitro and in vivo settings and analysed its effect on T cell development. We found that Fli-1 overexpression perturbed the DN to DP transition and inhibited CD4 development whilst enhancing CD8 development both in vitro and in vivo. Surprisingly, Fli-1 overexpression in vivo eventuated in development of pre-T cell lymphoblastic leukaemia/lymphoma (pre-T LBL). Known Fli-1 target genes such as the pro-survival Bcl-2 family members were not found to be upregulated. In contrast, we found increased NOTCH1 expression in all Fli-1 T cells and detected Notch1 mutations in all tumours. These data show a novel function for Fli-1 in T cell development and leukaemogenesis and provide a new mouse model of pre-T LBL to identify treatment options that target the Fli-1 and Notch1 signalling pathways.
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Affiliation(s)
- Monique F. M. A. Smeets
- Haematology and Leukaemia Unit, St. Vincent’s Institute, University of Melbourne, Fitzroy, Victoria, Australia
| | - Angela C. Chan
- Department of Microbiology and Immunology, University of Melbourne, Parkville, Victoria, Australia
| | - Samantha Dagger
- School of Pathology and Laboratory Medicine, University of Western Australia, Crawley, Western Australia, Australia
| | | | - Andrew Wei
- Department of Clinical Haematology, The Alfred Hospital and The Australian Centre for Blood Diseases, Monash University, Melbourne, Victoria, Australia
| | - David J. Izon
- Haematology and Leukaemia Unit, St. Vincent’s Institute, University of Melbourne, Fitzroy, Victoria, Australia
- * E-mail:
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14
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Wang HC, Peng V, Zhao Y, Sun XH. Enhanced Notch activation is advantageous but not essential for T cell lymphomagenesis in Id1 transgenic mice. PLoS One 2012; 7:e32944. [PMID: 22393458 PMCID: PMC3290631 DOI: 10.1371/journal.pone.0032944] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2011] [Accepted: 02/02/2012] [Indexed: 01/06/2023] Open
Abstract
T cell lymphoblastic leukemia (T-ALL) is known to be associated with chromosomal abnormalities that lead to aberrant expression of a number of transcription factors such as TAL1, which dimerizes with basic helix-loop-helix (bHLH) E proteins and inhibits their function. Activated Notch receptors also efficiently induce T cell leukemogenesis in mouse models. Interestingly, gain-of-function mutations or cryptic transcription initiation of the Notch1 gene have been frequently found in both human and mouse T-ALL. However, the correlations between these alterations and overall Notch activities or leukemogenesis have not been thoroughly evaluated. Therefore, we made use of our collection of T cell lymphomas developed in transgenic mice expressing Id1, which like TAL1, inhibits E protein function. By comparing expression levels of Notch target genes in Id1-expressing tumors to those in tumors induced by a constitutively active form of Notch1, N1C, we were able to assess the overall activities of Notch pathways and conclude that the majority of Id1-expressing tumors had elevated Notch function to a varying degree. However, 26% of the Id1-expressing tumors had no evidence of enhanced Notch activation, but that did not delay the onset of tumorigenesis. Furthermore, we examined the genetic or epigenetic alterations thought to contribute to ligand-independent activation or protein stabilization of Notch1 and found that some of the Id1-expressing tumors acquired these changes, but they are not uniformly associated with elevated Notch activities in Id1 tumor samples. In contrast, N1C-expressing tumors do not harbor any PEST domain mutations nor exhibit intragenic transcription initiation. Taken together, it appears that Notch activation provides Id1-expressing tumor cells with selective advantages in growth and survival. However, this may not be absolutely essential for lymphomagenesis in Id1 transgenic mice and additional factors could also cooperate with Id1 to induce T cell lymphoma. Therefore, a broad approach is necessary in designing T-ALL therapy.
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Affiliation(s)
- Hong-Cheng Wang
- Immunobiology and Cancer Research Program, Oklahoma Medical Research Foundation, Oklahoma City, Oklahoma, United States of America
| | - Vincent Peng
- Oklahoma School of Science and Mathematics, Oklahoma City, Oklahoma, United States of America
| | - Ying Zhao
- Immunobiology and Cancer Research Program, Oklahoma Medical Research Foundation, Oklahoma City, Oklahoma, United States of America
| | - Xiao-Hong Sun
- Immunobiology and Cancer Research Program, Oklahoma Medical Research Foundation, Oklahoma City, Oklahoma, United States of America
- * E-mail:
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15
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Koch U, Radtke F. Notch in T-ALL: new players in a complex disease. Trends Immunol 2011; 32:434-42. [DOI: 10.1016/j.it.2011.06.005] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2011] [Revised: 06/03/2011] [Accepted: 06/06/2011] [Indexed: 11/29/2022]
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16
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Abstract
Identifying the normal cell from which a tumor originates is crucial to understanding the etiology of that cancer. However, retrospective identification of the cell of origin in cancer is challenging because of the accumulation of genetic and epigenetic changes in tumor cells. The biologic state of the cell of origin likely influences the genetic events that drive transformation. We directly tested this hypothesis by performing a Sleeping Beauty transposon mutagenesis screen in which common insertion sites were identified in tumors that were produced by mutagenesis of cells at varying time points throughout the T lineage. Mutation and gene expression data derived from these tumors were then compared with data obtained from a panel of 84 human T-cell acute lymphoblastic leukemia samples, including copy number alterations and gene expression profiles. This revealed that altering the cell of origin produces tumors that model distinct subtypes of human T-cell acute lymphoblastic leukemia, suggesting that even subtle changes in the cell of origin dramatically affect genetic selection in tumors. These findings have broad implications for the genetic analysis of human cancers as well as the production of mouse models of cancer.
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17
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Steininger A, Möbs M, Ullmann R, Köchert K, Kreher S, Lamprecht B, Anagnostopoulos I, Hummel M, Richter J, Beyer M, Janz M, Klemke CD, Stein H, Dörken B, Sterry W, Schrock E, Mathas S, Assaf C. Genomic loss of the putative tumor suppressor gene E2A in human lymphoma. ACTA ACUST UNITED AC 2011; 208:1585-93. [PMID: 21788410 PMCID: PMC3149217 DOI: 10.1084/jem.20101785] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
The transcription factor E2A is essential for lymphocyte development. In this study, we describe a recurrent E2A gene deletion in at least 70% of patients with Sézary syndrome (SS), a subtype of T cell lymphoma. Loss of E2A results in enhanced proliferation and cell cycle progression via derepression of the protooncogene MYC and the cell cycle regulator CDK6. Furthermore, by examining the gene expression profile of SS cells after restoration of E2A expression, we identify several E2A-regulated genes that interfere with oncogenic signaling pathways, including the Ras pathway. Several of these genes are down-regulated or lost in primary SS tumor cells. These data demonstrate a tumor suppressor function of E2A in human lymphoid cells and could help to develop new treatment strategies for human lymphomas with altered E2A activity.
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Affiliation(s)
- Anne Steininger
- Max Planck Institute for Molecular Genetics, 14195 Berlin, Germany
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18
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Gómez-del Arco P, Kashiwagi M, Jackson AF, Naito T, Zhang J, Liu F, Kee B, Vooijs M, Radtke F, Redondo JM, Georgopoulos K. Alternative promoter usage at the Notch1 locus supports ligand-independent signaling in T cell development and leukemogenesis. Immunity 2010; 33:685-98. [PMID: 21093322 DOI: 10.1016/j.immuni.2010.11.008] [Citation(s) in RCA: 77] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2010] [Revised: 08/12/2010] [Accepted: 09/15/2010] [Indexed: 01/20/2023]
Abstract
Loss of the transcription factor Ikaros is correlated with Notch receptor activation in T cell acute lymphoblastic leukemia (T-ALL). However, the mechanism remains unknown. We identified promoters in Notch1 that drove the expression of Notch1 proteins in the absence of a ligand. Ikaros bound to both canonical and alternative Notch1 promoters and its loss increased permissive chromatin, facilitating recruitment of transcription regulators. At early stages of leukemogenesis, increased basal expression from the canonical and 5'-alternative promoters initiated a feedback loop, augmenting Notch1 signaling. Ikaros also repressed intragenic promoters for ligand-independent Notch1 proteins that are cryptic in wild-type cells, poised in preleukemic cells, and active in leukemic cells. Only ligand-independent Notch1 isoforms were required for Ikaros-mediated leukemogenesis. Notch1 alternative-promoter usage was observed during T cell development and T-ALL progression. Thus, a network of epigenetic and transcriptional regulators controls conventional and unconventional Notch signaling during normal development and leukemogenesis.
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Affiliation(s)
- Pablo Gómez-del Arco
- Vascular Biology and Inflammation Department, Centro Nacional de Investigaciones Cardiovasculares (CNIC), Madrid 28029, Spain
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19
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Aster JC, Blacklow SC, Pear WS. Notch signalling in T-cell lymphoblastic leukaemia/lymphoma and other haematological malignancies. J Pathol 2010; 223:262-73. [PMID: 20967796 DOI: 10.1002/path.2789] [Citation(s) in RCA: 132] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2010] [Revised: 09/10/2010] [Accepted: 09/16/2010] [Indexed: 12/21/2022]
Abstract
Notch receptors participate in a highly conserved signalling pathway that regulates normal development and tissue homeostasis in a context- and dose-dependent manner. Deregulated Notch signalling has been implicated in many diseases, but the clearest example of a pathogenic role is found in T-cell lymphoblastic leukaemia/lymphoma (T-LL), in which the majority of human and murine tumours have acquired mutations that lead to aberrant increases in Notch1 signalling. Remarkably, it appears that the selective pressure for Notch mutations is virtually unique among cancers to T-LL, presumably reflecting a special context-dependent role for Notch in normal T-cell progenitors. Nevertheless, there are some recent reports suggesting that Notch signalling has subtle, yet important roles in other forms of haematological malignancy as well. Here, we review the role of Notch signalling in various blood cancers, focusing on T-LL with an eye towards targeted therapeutics.
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Affiliation(s)
- Jon C Aster
- Department of Pathology, Brigham and Women's Hospital, Boston, MA 02115, USA.
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20
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Masuda S, Kumano K, Suzuki T, Tomita T, Iwatsubo T, Natsugari H, Tojo A, Shibutani M, Mitsumori K, Hanazono Y, Ogawa S, Kurokawa M, Chiba S. Dual antitumor mechanisms of Notch signaling inhibitor in a T-cell acute lymphoblastic leukemia xenograft model. Cancer Sci 2009; 100:2444-50. [PMID: 19775286 PMCID: PMC11159026 DOI: 10.1111/j.1349-7006.2009.01328.x] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
Constitutive activation of Notch signaling is required for the proliferation of a subgroup of human T-cell acute lymphoblastic leukemias (T-ALL). Previous in vitro studies have demonstrated the therapeutic potential of Notch signaling inhibitors for treating T-ALL. To further examine this possibility, we applied a gamma-secretase inhibitor (GSI) to T-ALL xenograft models. Treatment of established subcutaneous tumors with GSI resulted in partial or complete regression of tumors arising from four T-ALL cell lines that were also sensitive to GSI in vitro. To elucidate the mechanism of action, we transduced DND-41 cells with the active form of Notch1 (aN1), which conferred resistance to in vitro GSI treatment. Nevertheless, in vivo treatment with GSI induced a partial but significant regression of subcutaneous tumors that developed from aN1-transduced DND-41 cells, whereas it induced complete regression of tumors that developed from mock-transduced DND-41 cells. These findings indicate that the remarkable efficacy of GSI might be attributable to dual mechanisms, directly via apoptosis of DND-41 cells through the inhibition of cell-autonomous Notch signaling, and indirectly via disturbance of tumor angiogenesis through the inhibition of non-cell-autonomous Notch signaling.
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Affiliation(s)
- Shigeo Masuda
- Department of Cell Therapy and Transplantation Medicine, University of Tokyo Hospital, Tokyo, Japan
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21
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Hes1 potentiates T cell lymphomagenesis by up-regulating a subset of notch target genes. PLoS One 2009; 4:e6678. [PMID: 19688092 PMCID: PMC2722736 DOI: 10.1371/journal.pone.0006678] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2009] [Accepted: 07/21/2009] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Hairy/Enhancer of Split (Hes) proteins are targets of the Notch signaling pathway and make up a class of basic helix-loop-helix (bHLH) proteins that function to repress transcription. Data from Hes1 deficient mice suggested that Hes1, like Notch1, is necessary for the progression of early T cell progenitors. Constitutive activation of Notch is known to cause T cell leukemia or lymphoma but whether Hes1 has any oncogenic activity is not known. METHODOLOGY/PRINCIPAL FINDINGS We generated mice carrying a Hes1 transgene under control of the proximal promote of the lck gene. Hes1 expression led to a reduction in numbers of total thymocytes, concomitant with the increased percentage and number of immature CD8+ (ISP) T cells and sustained CD25 expression in CD4+CD8+ double positive (DP) thymocytes. Hes1 transgenic mice develop thymic lymphomas at about 20 weeks of age with a low penetrance. However, expression of Hes1 significantly shortens the latency of T cell lymphoma developed in Id1 transgenic mice, where the function of bHLH E proteins is inhibited. Interestingly, Hes1 increased expression of a subset of Notch target genes in pre-malignant ISP and DP thymocytes, which include Notch1, Notch3 and c-myc, thus suggesting a possible mechanism for lymphomagenesis. CONCLUSIONS/SIGNIFICANCE We have demonstrated for the first time that Hes1 potentiates T cell lymphomagenesis, by up-regulating a subset of Notch target genes and by causing an accumulation of ISP thymocytes particularly vulnerable to oncogenic transformation.
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22
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Cullion K, Draheim KM, Hermance N, Tammam J, Sharma VM, Ware C, Nikov G, Krishnamoorthy V, Majumder PK, Kelliher MA. Targeting the Notch1 and mTOR pathways in a mouse T-ALL model. Blood 2009; 113:6172-81. [PMID: 19246562 PMCID: PMC2699237 DOI: 10.1182/blood-2008-02-136762] [Citation(s) in RCA: 115] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2008] [Accepted: 01/30/2009] [Indexed: 12/23/2022] Open
Abstract
Mutations in NOTCH1 are frequently detected in patients with T-cell acute lymphoblastic leukemia (T-ALL) and in mouse T-ALL models. Treatment of mouse or human T-ALL cell lines in vitro with gamma-secretase inhibitors (GSIs) results in growth arrest and/or apoptosis. These studies suggest GSIs as potential therapeutic agents in the treatment of T-ALL. To determine whether GSIs have antileukemic activity in vivo, we treated near-end-stage Tal1/Ink4a/Arf+/- leukemic mice with vehicle or with a GSI developed by Merck (MRK-003). We found that GSI treatment significantly extended the survival of leukemic mice compared with vehicle-treated mice. Notch1 target gene expression was repressed and increased numbers of apoptotic cells were observed in the GSI-treated mice, demonstrating that Notch1 inhibition in vivo induces apoptosis. T-ALL cell lines also exhibit PI3K/mTOR pathway activation, indicating that rapamycin may also have therapeutic benefit. When GSIs are administered in combination with rapamycin, mTOR kinase activity is ablated and apoptosis induced. Moreover, GSI and rapamycin treatment inhibits human T-ALL growth and extends survival in a mouse xenograft model. This work supports the idea of targeting NOTCH1 in T-ALL and suggests that inhibition of the mTOR and NOTCH1 pathways may have added efficacy.
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Affiliation(s)
- Kathleen Cullion
- Department of Cancer Biology and the Cancer Center, University of Massachusetts Medical School, Worcester, MA 01605, USA
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23
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24
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K-RasG12D-induced T-cell lymphoblastic lymphoma/leukemias harbor Notch1 mutations and are sensitive to gamma-secretase inhibitors. Blood 2008; 112:3373-82. [PMID: 18663146 DOI: 10.1182/blood-2008-03-147587] [Citation(s) in RCA: 71] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
To study the impact of oncogenic K-Ras on T-cell leukemia/lymphoma development and progression, we made use of a conditional K-Ras(G12D) murine knockin model, in which oncogenic K-Ras is expressed from its endogenous promoter. Transplantation of whole bone marrow cells that express oncogenic K-Ras into wild-type recipient mice resulted in a highly penetrant, aggressive T-cell leukemia/lymphoma. The lymphoblasts were composed of a CD4/CD8 double-positive population that aberrantly expressed CD44. Thymi of primary donor mice showed reduced cellularity, and immunophenotypic analysis demonstrated a block in differentiation at the double-negative 1 stage. With progression of disease, approximately 50% of mice acquired Notch1 mutations within the PEST domain. Of note, primary lymphoblasts were hypersensitive to gamma-secretase inhibitor treatment, which is known to impair Notch signaling. This inhibition was Notch-specific as assessed by down-regulation of Notch1 target genes and intracellular cleaved Notch. We also observed that the oncogenic K-Ras-induced T-cell disease was responsive to rapamycin and inhibitors of the RAS/MAPK pathway. These data indicate that patients with T-cell leukemia with K-Ras mutations may benefit from therapies that target the NOTCH pathway alone or in combination with inhibition of the PI3K/AKT/MTOR and RAS/MAPK pathways.
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25
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Abstract
T-cell acute lymphoblastic leukaemia (T-ALL) is induced by the transformation of T-cell progenitors and mainly occurs in children and adolescents. Although treatment outcome in patients with T-ALL has improved in recent years, patients with relapsed disease continue to have a poor prognosis. It is therefore important to understand the molecular pathways that control both the induction of transformation and the treatment of relapsed disease. In this Review, we focus on the molecular mechanisms responsible for disease induction and maintenance. We also compare the physiological progression of T-cell differentiation with T-cell transformation, highlighting the close relationship between these two processes. Finally, we discuss potential new therapies that target oncogenic pathways in T-ALL.
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26
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Aster JC, Pear WS, Blacklow SC. Notch signaling in leukemia. ANNUAL REVIEW OF PATHOLOGY-MECHANISMS OF DISEASE 2008; 3:587-613. [PMID: 18039126 DOI: 10.1146/annurev.pathmechdis.3.121806.154300] [Citation(s) in RCA: 201] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Recent discoveries indicate that gain-of-function mutations in the Notch1 receptor are very common in human T cell acute lymphoblastic leukemia/lymphoma. This review discusses what these mutations have taught us about normal and pathophysiologic Notch1 signaling, and how these insights may lead to new targeted therapies for patients with this aggressive form of cancer.
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Affiliation(s)
- Jon C Aster
- Department of Pathology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA.
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27
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van Hamburg JP, de Bruijn MJW, Dingjan GM, Beverloo HB, Diepstraten H, Ling KW, Hendriks RW. Cooperation of Gata3, c-Myc and Notch in malignant transformation of double positive thymocytes. Mol Immunol 2008; 45:3085-95. [PMID: 18471881 DOI: 10.1016/j.molimm.2008.03.018] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2008] [Revised: 03/07/2008] [Accepted: 03/10/2008] [Indexed: 12/16/2022]
Abstract
Gata transcription factors are critical regulators of proliferation and differentiation implicated in various human cancers, but specific genes activated by Gata proteins remain to be identified. We previously reported that enforced expression of Gata3 during T cell development in CD2-Gata3 transgenic mice induced CD4(+)CD8(+) double-positive (DP) T cell lymphoma. Here, we show that the presence of the DO11.10 T-cell receptor transgene, which directs DP cells towards the CD4 lineage, resulted in enhanced lymphoma development and a dramatic increase in thymocyte cell size in CD2-Gata3 transgenic mice. CD2-Gata3 DP cells expressed high levels of the proto-oncogene c-Myc but the Notch1 signaling pathway, which is known to induce c-Myc, was not activated. Gene expression profiling showed that in CD2-Gata3 lymphoma cells transcription of c-Myc and its target genes was further increased. A substantial fraction of CD2-Gata3 lymphomas had trisomy of chromosome 15, leading to an increased c-Myc gene dose. Interestingly, most lymphomas showed high expression of the Notch targets Deltex1 and Hes1, often due to activating Notch1 PEST domain mutations. Therefore, we conclude that enforced Gata3 expression converts DP thymocytes into a pre-malignant state, characterized by high c-Myc expression, whereby subsequent induction of Notch1 signaling cooperates to establish malignant transformation. The finding that Gata3 regulates c-Myc expression levels, in a direct or indirect fashion, may explain the parallel phenotypes of mice with overexpression or deficiency of either of the two transcription factors.
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28
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Expression of helix-loop-helix proteins in classical hodgkin lymphoma: a possible explanation for a characteristic immunophenotype. Adv Anat Pathol 2008; 15:97-104. [PMID: 18418090 DOI: 10.1097/pap.0b013e3181661363] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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29
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Beta-catenin expression results in p53-independent DNA damage and oncogene-induced senescence in prelymphomagenic thymocytes in vivo. Mol Cell Biol 2007; 28:1713-23. [PMID: 18160717 DOI: 10.1128/mcb.01360-07] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The expression of beta-catenin, a potent oncogene, is causally linked to tumorigenesis. Therefore, it was surprising that the transgenic expression of oncogenic beta-catenin in thymocytes resulted in thymic involution instead of lymphomagenesis. In this report, we demonstrate that this is because the expression of oncogenic beta-catenin induces DNA damage, growth arrest, oncogene-induced senescence (OIS), and apoptosis of immature thymocytes. In p53-deficient mice, the expression of oncogenic beta-catenin still results in DNA damage and OIS, but the thymocytes survive and eventually progress to thymic lymphoma. beta-Catenin-induced thymic lymphomas are distinct from lymphomas that arise in p53(-/-) mice. They are CD4(-) CD8(-), while p53-dependent lymphomas are largely CD4(+) CD8(+), and they develop at an earlier age and in the absence of c-Myc expression or Notch1 signaling. Thus, we report that oncogenic beta-catenin-induced, p53-independent growth arrest and OIS and p53-dependent apoptosis protect developing thymocytes from transformation by oncogenic beta-catenin.
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30
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Lef-1: NOTCHed up in T-cell lymphomas. Blood 2007. [DOI: 10.1182/blood-2007-07-100156] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
In this issue of Blood, Spaulding and colleagues show that Lef-1, one of the transcription factors mediating Wnt signaling, is a transcriptional target of Notch in T-cell lymphomas. Notch-activating mutations are commonly found in human T-lineage acute lymphoblastic leukemia (T-ALL) cases, while activation of Wnt/β-catenin signaling has recently been shown to induce T-cell leukemia in mice. The proposed regulation of Lef-1 transcription by Notch suggests the intriguing possibility that the Notch and Wnt pathways are closely intertwined in the etiology of T-cell leukemia.
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31
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Bessette K, Lang ML, Fava RA, Grundy M, Heinen J, Horne L, Spolski R, Al-Shami A, Morse HC, Leonard WJ, Kelly JA. A Stat5b transgene is capable of inducing CD8+ lymphoblastic lymphoma in the absence of normal TCR/MHC signaling. Blood 2007; 111:344-50. [PMID: 17890450 PMCID: PMC2200817 DOI: 10.1182/blood-2007-04-084707] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Stat5 proteins are critical signaling molecules activated by many cytokines. Within the immune system, Stat5 plays important roles related to the development of thymocytes and proliferation of T cells. Stat5 has been implicated in malignant transformation, and moreover, the activated tyrosine phosphorylated form of Stat5 is frequently observed in human lymphomas. We previously demonstrated the oncogenic potential of Stat5, with thymic lymphoblastic lymphomas developing in a significant proportion of transgenic (TG) mice overexpressing Stat5a or Stat5b in lymphocytes. In addition, immunization or expression of a T-cell receptor (TCR) transgene augmented the rate of tumor formation. Here, we investigate the mechanism of Stat5-mediated lymphomagenesis by exploring the contributions of major histocompatibility complex (MHC)/TCR and pre-TCR signals. We present data demonstrating that Stat5b TG mice unexpectedly develop CD8(+) lymphoma even in the absence of either pre-TCR signaling or normal thymic selection. Indeed, acceleration of Stat5b transgene-mediated lymphoma occurred on TCRalpha(-/-) and pre-TCRalpha(-/-) backgrounds. In light of these data, we propose a model in which alterations in T-cell development at the double-negative/double-positive (DN/DP) stages cooperate with cytokine-mediated pathways in immature thymocytes to give rise to lymphoblastic T-cell lymphomas in Stat5b TG mice.
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MESH Headings
- Animals
- CD8-Positive T-Lymphocytes/pathology
- CD8-Positive T-Lymphocytes/physiology
- Cell Transformation, Neoplastic/immunology
- Killer Cells, Natural/pathology
- Killer Cells, Natural/physiology
- Major Histocompatibility Complex/physiology
- Mice
- Mice, Transgenic
- Precursor Cell Lymphoblastic Leukemia-Lymphoma/metabolism
- Precursor Cell Lymphoblastic Leukemia-Lymphoma/pathology
- Receptors, Antigen, T-Cell, alpha-beta/metabolism
- Receptors, Antigen, T-Cell, gamma-delta/metabolism
- STAT5 Transcription Factor/genetics
- STAT5 Transcription Factor/metabolism
- Signal Transduction/immunology
- T-Lymphocytes/pathology
- T-Lymphocytes/physiology
- Transgenes/physiology
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Affiliation(s)
- Katherine Bessette
- White River Junction Veteran's Association, White River Junction, VT, USA
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32
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Thompson BJ, Buonamici S, Sulis ML, Palomero T, Vilimas T, Basso G, Ferrando A, Aifantis I. The SCFFBW7 ubiquitin ligase complex as a tumor suppressor in T cell leukemia. ACTA ACUST UNITED AC 2007; 204:1825-35. [PMID: 17646408 PMCID: PMC2118676 DOI: 10.1084/jem.20070872] [Citation(s) in RCA: 363] [Impact Index Per Article: 21.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Recent studies have shown that activating mutations of NOTCH1 are responsible for the majority of T cell acute lymphoblastic leukemia (T-ALL) cases. Most of these mutations truncate its C-terminal domain, a region that is important for the NOTCH1 proteasome-mediated degradation. We report that the E3 ligase FBW7 targets NOTCH1 for ubiquitination and degradation. Our studies map in detail the amino acid degron sequence required for NOTCH1–FBW7 interaction. Furthermore, we identify inactivating FBW7 mutations in a large fraction of human T-ALL lines and primary leukemias. These mutations abrogate the binding of FBW7 not only to NOTCH1 but also to the two other characterized targets, c-Myc and cyclin E. The majority of the FBW7 mutations were present during relapse, and they were associated with NOTCH1 HD mutations. Interestingly, most of the T-ALL lines harboring FBW7 mutations were resistant to γ-secretase inhibitor treatment and this resistance appeared to be related to the stabilization of the c-Myc protein. Our data suggest that FBW7 is a novel tumor suppressor in T cell leukemia, and implicate the loss of FBW7 function as a potential mechanism of drug resistance in T-ALL.
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Affiliation(s)
- Benjamin J Thompson
- Department of Pathology, New York University School of Medicine, New York, NY 10016, USA
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33
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Spaulding C, Reschly EJ, Zagort DE, Yashiro-Ohtani Y, Beverly LJ, Capobianco A, Pear WS, Kee BL. Notch1 co-opts lymphoid enhancer factor 1 for survival of murine T-cell lymphomas. Blood 2007; 110:2650-8. [PMID: 17585052 DOI: 10.1182/blood-2007-04-084202] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Oncogenic Notch1 mutations are found in most T-lineage acute lymphoblastic leukemias in humans and T-cell lymphomas in mice. However, the mechanism by which Notch1 promotes transformation or maintains malignant cell survival has not been determined fully. Here, we report that expression of the transcription factor lymphoid enhancer factor 1 (Lef1) is Notch dependent in murine T-cell lymphomas in vitro and in vivo, and that the intracellular domain of Notch1 (ICN1) is present at the Lef1 promoter. Lef1 expression is not Notch dependent in primary T-cell progenitors, but Lef1 mRNA is increased by ectopic expression of ICN1 in these cells. We show that Lef1 is required for survival of T-cell lymphoma lines, and that ectopic expression of Lef1 delays lymphoma cell death in the absence of Notch signaling, indicating that Lef1 is an important Notch target in these cells. Therefore, Notch1 co-opts Lef1 during the process of transformation to maintain survival of T-cell lymphomas.
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34
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Guo Z, Dose M, Kovalovsky D, Chang R, O'Neil J, Look AT, von Boehmer H, Khazaie K, Gounari F. Beta-catenin stabilization stalls the transition from double-positive to single-positive stage and predisposes thymocytes to malignant transformation. Blood 2007; 109:5463-72. [PMID: 17317856 PMCID: PMC1890819 DOI: 10.1182/blood-2006-11-059071] [Citation(s) in RCA: 103] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2006] [Accepted: 02/15/2007] [Indexed: 11/20/2022] Open
Abstract
Activation of beta-catenin has been causatively linked to the etiology of colon cancer. Conditional stabilization of this molecule in pro-T cells promotes thymocyte development without the requirement for pre-TCR signaling. We show here that activated beta-catenin stalls the developmental transition from the double-positive (DP) to the single-positive (SP) thymocyte stage and predisposes DP thymocytes to transformation. beta-Catenin-induced thymic lymphomas have a leukemic arrest at the early DP stage. Lymphomagenesis requires Rag activity, which peaks at this developmental stage, as well as additional secondary genetic events. A consistent secondary event is the transcriptional up-regulation of c-Myc, whose activity is required for transformation because its conditional ablation abrogates lymphomagenesis. In contrast, the expression of Notch receptors as well as targets is reduced in DP thymocytes with stabilized beta-catenin and remains low in the lymphomas, indicating that Notch activation is not required or selected for in beta-catenin-induced lymphomas. Thus, beta-catenin activation may provide a mechanism for the induction of T-cell-acute lymphoblastic leukemia (T-ALL) that does not depend on Notch activation.
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Affiliation(s)
- Zhuyan Guo
- Molecular Oncology Research Institute, Tufts-New England Medical Center, Boston, MA 02111, USA
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35
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Fasseu M, Aplan PD, Chopin M, Boissel N, Bories JC, Soulier J, von Boehmer H, Sigaux F, Regnault A. p16INK4A tumor suppressor gene expression and CD3epsilon deficiency but not pre-TCR deficiency inhibit TAL1-linked T-lineage leukemogenesis. Blood 2007; 110:2610-9. [PMID: 17507663 PMCID: PMC1988920 DOI: 10.1182/blood-2007-01-066209] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
Inactivation of the CDKN2 genes that encode the p16(INK4A) and p14(ARF) proteins occurs in the majority of human T-cell acute lymphoblastic leukemias (T-ALLs). Ectopic expression of TAL1 and LMO1 genes is linked to the development of T-ALL in humans. In TAL1xLMO1 mice, leukemia develops in 100% of mice at 5 months. To identify the molecular events crucial to leukemic transformation, we produced several mouse models. We report here that expression of P16(INK4A) in developing TAL1xLMO1 thymocytes blocks leukemogenesis in the majority of the mice, and the leukemias that eventually develop show P16(INK4A) loss of expression. Events related to the T-cell receptor beta selection process are thought to be important for leukemic transformation. We show here that the absence of the pTalpha chain only slightly delays the appearance of TAL1xLMO1-induced T-ALL, which indicates a minor role of the pTalpha chain. We also show that the CD3epsilon-mediated signal transduction pathway is essential for this transformation process, since the TAL1xLMO1xCD3epsilon-deficient mice do not develop T-ALL for up to 1 year.
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MESH Headings
- Animals
- Basic Helix-Loop-Helix Transcription Factors/genetics
- Basic Helix-Loop-Helix Transcription Factors/metabolism
- CD3 Complex/genetics
- CD3 Complex/metabolism
- Cell Differentiation
- Cell Lineage
- Cell Transformation, Neoplastic/genetics
- Cell Transformation, Neoplastic/metabolism
- Cell Transformation, Neoplastic/pathology
- Cyclin D3
- Cyclin-Dependent Kinase Inhibitor p16/genetics
- Cyclin-Dependent Kinase Inhibitor p16/metabolism
- Cyclins/metabolism
- Gene Expression Regulation, Neoplastic
- Humans
- LIM Domain Proteins
- Leukemia/genetics
- Leukemia/metabolism
- Leukemia/pathology
- Mice
- Mice, Transgenic
- Mutation/genetics
- Nuclear Proteins/genetics
- Nuclear Proteins/metabolism
- Proto-Oncogene Proteins/genetics
- Proto-Oncogene Proteins/metabolism
- RNA, Messenger/genetics
- Receptor, Notch1/genetics
- Receptor, Notch1/metabolism
- Receptors, Antigen, T-Cell/deficiency
- Receptors, Antigen, T-Cell/genetics
- Receptors, Antigen, T-Cell/metabolism
- Survival Rate
- T-Cell Acute Lymphocytic Leukemia Protein 1
- Thymus Gland/cytology
- Thymus Gland/metabolism
- Transcription Factors/genetics
- Transcription Factors/metabolism
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Affiliation(s)
- Magali Fasseu
- Institut National de la Santé et de la Recherche Médicale (INSERM) U462, Institut Universitaire d'Hématologie, Hôpital Saint-Louis, Paris, France
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36
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Chan SM, Weng AP, Tibshirani R, Aster JC, Utz PJ. Notch signals positively regulate activity of the mTOR pathway in T-cell acute lymphoblastic leukemia. Blood 2007; 110:278-86. [PMID: 17363738 PMCID: PMC1896117 DOI: 10.1182/blood-2006-08-039883] [Citation(s) in RCA: 211] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Constitutive Notch activation is required for the proliferation of a subgroup of T-cell acute lymphoblastic leukemia (T-ALL). Downstream pathways that transmit pro-oncogenic signals are not well characterized. To identify these pathways, protein microarrays were used to profile the phosphorylation state of 108 epitopes on 82 distinct signaling proteins in a panel of 13 T-cell leukemia cell lines treated with a gamma-secretase inhibitor (GSI) to inhibit Notch signals. The microarray screen detected GSI-induced hypophosphorylation of multiple signaling proteins in the mTOR pathway. This effect was rescued by expression of the intracellular domain of Notch and mimicked by dominant negative MAML1, confirming Notch specificity. Withdrawal of Notch signals prevented stimulation of the mTOR pathway by mitogenic factors. These findings collectively suggest that the mTOR pathway is positively regulated by Notch in T-ALL cells. The effect of GSI on the mTOR pathway was independent of changes in phosphatidylinositol-3 kinase and Akt activity, but was rescued by expression of c-Myc, a direct transcriptional target of Notch, implicating c-Myc as an intermediary between Notch and mTOR. T-ALL cell growth was suppressed in a highly synergistic manner by simultaneous treatment with the mTOR inhibitor rapamycin and GSI, which represents a rational drug combination for treating this aggressive human malignancy.
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Affiliation(s)
- Steven M Chan
- Division of Immunology, Department of Medicine, Stanford University School of Medicine, Stanford, CA 94305, USA
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37
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Xu W, Kee BL. Growth factor independent 1B (Gfi1b) is an E2A target gene that modulates Gata3 in T-cell lymphomas. Blood 2007; 109:4406-14. [PMID: 17272506 DOI: 10.1182/blood-2006-08-043331] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
The E2A transcription factors are required for normal T lymphopoiesis and to prevent T-lymphocyte progenitor transformation. Ectopic expression of E2A proteins in E2A-deficient lymphomas results in growth arrest and apoptosis, indicating that these cells remain responsive to the targets of E2A. Here we identify the transcriptional repressor growth factor independent 1B (Gfi1b) as a target of E2A that promotes growth arrest and apoptosis in lymphomas. Gfi1b expression in primary T-lymphocyte progenitors is dependent on E2A and excess Gfi1b prevents the outgrowth of T lymphocyte progenitors in vitro. Gfi1b represses expression of Gata3, a transcription factor whose appropriate regulation is required for survival of lymphomas and T-lymphocyte progenitors. We also show that ectopic expression of Gata3 in lymphomas promotes expression of Gfi1b, indicating that these proteins may function in an autoregulatory loop that maintains appropriate levels of Gata3. Therefore, we propose that E2A proteins prevent lymphoma cell expansion, at least in part through regulation of Gfi1b and modulation of Gata3 expression.
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Affiliation(s)
- Wei Xu
- Committee on Cancer Biology, University of Chicago, Chicago, IL 60637, USA
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38
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Roy M, Pear WS, Aster JC. The multifaceted role of Notch in cancer. Curr Opin Genet Dev 2006; 17:52-9. [PMID: 17178457 DOI: 10.1016/j.gde.2006.12.001] [Citation(s) in RCA: 233] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2006] [Accepted: 12/11/2006] [Indexed: 12/11/2022]
Abstract
The diverse roles that Notch signals play during the development and maintenance of normal tissues are recapitulated in different forms of cancer. Depending on the tumor type, Notch can variously promote or limit tumor growth through either cell autonomous or cell non-autonomous effects on differentiation, cellular metabolism, cell cycle progression, angiogenesis, and possibly self-renewal and immune function. Of particular interest, recent findings indicate that a high fraction of T-cell acute lymphoblastic leukemias and lymphomas have activating mutations in the Notch 1 receptor, and that Notch signaling might have a role in the maintenance of normal and malignant stem cells.
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Affiliation(s)
- Monideepa Roy
- Department of Pathology, Brigham and Women's Hospital, 75 Francis Street, Boston, MA 02115, USA
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39
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Sharma VM, Calvo JA, Draheim KM, Cunningham LA, Hermance N, Beverly L, Krishnamoorthy V, Bhasin M, Capobianco AJ, Kelliher MA. Notch1 contributes to mouse T-cell leukemia by directly inducing the expression of c-myc. Mol Cell Biol 2006; 26:8022-31. [PMID: 16954387 PMCID: PMC1636748 DOI: 10.1128/mcb.01091-06] [Citation(s) in RCA: 214] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Recent work with mouse models and human leukemic samples has shown that gain-of-function mutation(s) in Notch1 is a common genetic event in T-cell acute lymphoblastic leukemia (T-ALL). The Notch1 receptor signals through a gamma-secretase-dependent process that releases intracellular Notch1 from the membrane to the nucleus, where it forms part of a transcriptional activator complex. To identify Notch1 target genes in leukemia, we developed mouse T-cell leukemic lines that express intracellular Notch1 in a doxycycline-dependent manner. Using gene expression profiling and chromatin immunoprecipitation, we identified c-myc as a novel, direct, and critical Notch1 target gene in T-cell leukemia. c-myc mRNA levels are increased in primary mouse T-cell tumors that harbor Notch1 mutations, and Notch1 inhibition decreases c-myc mRNA levels and inhibits leukemic cell growth. Retroviral expression of c-myc, like intracellular Notch1, rescues the growth arrest and apoptosis associated with gamma-secretase inhibitor treatment or Notch1 inhibition. Consistent with these findings, retroviral insertional mutagenesis screening of our T-cell leukemia mouse model revealed common insertions in either notch1 or c-myc genes. These studies define the Notch1 molecular signature in mouse T-ALL and importantly provide mechanistic insight as to how Notch1 contributes to human T-ALL.
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Affiliation(s)
- Vishva Mitra Sharma
- Department of Cancer Biology, University of Massachusetts Medical School, Worcester, MA 01605, USA
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40
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Grabher C, von Boehmer H, Look AT. Notch 1 activation in the molecular pathogenesis of T-cell acute lymphoblastic leukaemia. Nat Rev Cancer 2006; 6:347-59. [PMID: 16612405 DOI: 10.1038/nrc1880] [Citation(s) in RCA: 338] [Impact Index Per Article: 18.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
The chromosomal translocation t(7;9) in human T-cell acute lymphoblastic leukaemia (T-ALL) results in deregulated expression of a truncated, activated form of Notch 1 (TAN1) under the control of the T-cell receptor-beta (TCRB) locus. Although TAN1 efficiently induces T-ALL in mouse models, t(7;9) is present in less than 1% of human T-ALL cases. The recent discovery of novel activating mutations in NOTCH1 in more than 50% of human T-ALL samples has made it clear that Notch 1 is far more important in human T-ALL pathogenesis than previously suspected.
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Affiliation(s)
- Clemens Grabher
- Department of Pediatric Oncology, Dana-Farber Cancer Institute and Harvard Medical School, Boston, Massachusetts 02115, USA
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41
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Mansour MR. A role for aberrant Notch signaling in acute myeloid leukemia? Leuk Lymphoma 2006; 47:2280-1. [PMID: 17107898 DOI: 10.1080/10428190600908109] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Affiliation(s)
- Marc R Mansour
- Department of Haematology, University College London, London, UK.
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