1
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Azevedo ALKD, Gomig THB, Giner IS, Batista M, Marchini FK, Lima RS, de Andrade Urban C, Sebastião APM, Cavalli IJ, Ribeiro EMDSF. Comprehensive analysis of the large and small ribosomal proteins in breast cancer: Insights on proteomic and transcriptomic expression patterns, regulation, mutational landscape, and prognostic significance. Comput Biol Chem 2022; 100:107746. [DOI: 10.1016/j.compbiolchem.2022.107746] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2022] [Revised: 07/11/2022] [Accepted: 07/25/2022] [Indexed: 11/29/2022]
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2
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Li L, Yu J, Cheng S, Peng Z, Ben-David Y, Luo H. Transcription factor Fli-1 as a new target for antitumor drug development. Int J Biol Macromol 2022; 209:1155-1168. [PMID: 35447268 DOI: 10.1016/j.ijbiomac.2022.04.076] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2022] [Revised: 04/01/2022] [Accepted: 04/11/2022] [Indexed: 02/07/2023]
Abstract
The transcription factor Friend leukemia virus integration 1 (Fli-1) belonging to the E26 Transformation-Specific (ETS) transcription factor family is not only expressed in normal cells such as hematopoietic stem cells and vascular endothelial cells, but also abnormally expressed in various malignant tumors including Ewing sarcoma, Merkel cell sarcoma, small cell lung carcinoma, benign or malignant hemangioma, squamous cell carcinoma, adenocarcinoma, bladder cancer, leukemia, and lymphoma. Fli-1 binds to the promoter or enhancer of the target genes and participates in a variety of physiological and pathological processes of tumor cells, including cell growth, proliferation, differentiation, and apoptosis. The expression of Fli-1 gene is related to the specific biological functions and characteristics of the tissue in which it is located. In tumor research, Fli-1 gene is used as a specific marker for the occurrence, metastasis, efficacy, and prognosis of tumors, thus, a potential new target for tumor diagnosis and treatment. These studies indicated that Fli-1 may be a specific candidate for antitumor drug development. Recent studies identified small molecules regulating Fli-1 thanks to our screened strategy of natural products and their derivatives. Therefore, in this review, the advanced research on Fli-1 as a target for antitumor drug development is analyzed in different cancers. The inhibitors and agonists of Fli-1 that regulate its expression are introduced and their clinical applications in the treatment of cancer, thus providing new therapeutic strategies.
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Affiliation(s)
- Lanlan Li
- State Key Laboratory for Functions and Applications of Medicinal Plants, Guizhou Medical University, Guiyang 550014, P.R. China; College of Pharmacy, Guizhou Medical University, Guiyang 550025, P.R. China
| | - Jia Yu
- State Key Laboratory for Functions and Applications of Medicinal Plants, Guizhou Medical University, Guiyang 550014, P.R. China; The Key Laboratory of Chemistry for Natural Products of Guizhou Province and Chinese Academic of Science, Guiyang 550014, P.R. China
| | - Sha Cheng
- State Key Laboratory for Functions and Applications of Medicinal Plants, Guizhou Medical University, Guiyang 550014, P.R. China; The Key Laboratory of Chemistry for Natural Products of Guizhou Province and Chinese Academic of Science, Guiyang 550014, P.R. China
| | - Zhilin Peng
- State Key Laboratory for Functions and Applications of Medicinal Plants, Guizhou Medical University, Guiyang 550014, P.R. China; The Key Laboratory of Chemistry for Natural Products of Guizhou Province and Chinese Academic of Science, Guiyang 550014, P.R. China
| | - Yaacov Ben-David
- State Key Laboratory for Functions and Applications of Medicinal Plants, Guizhou Medical University, Guiyang 550014, P.R. China; The Key Laboratory of Chemistry for Natural Products of Guizhou Province and Chinese Academic of Science, Guiyang 550014, P.R. China
| | - Heng Luo
- State Key Laboratory for Functions and Applications of Medicinal Plants, Guizhou Medical University, Guiyang 550014, P.R. China; The Key Laboratory of Chemistry for Natural Products of Guizhou Province and Chinese Academic of Science, Guiyang 550014, P.R. China.
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3
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p53 activation during ribosome biogenesis regulates normal erythroid differentiation. Blood 2021; 137:89-102. [PMID: 32818241 DOI: 10.1182/blood.2019003439] [Citation(s) in RCA: 42] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2019] [Accepted: 08/03/2020] [Indexed: 12/22/2022] Open
Abstract
The role of ribosome biogenesis in erythroid development is supported by the recognition of erythroid defects in ribosomopathies in both Diamond-Blackfan anemia and 5q- syndrome. Whether ribosome biogenesis exerts a regulatory function on normal erythroid development is still unknown. In the present study, a detailed characterization of ribosome biogenesis dynamics during human and murine erythropoiesis showed that ribosome biogenesis is abruptly interrupted by the decline in ribosomal DNA transcription and the collapse of ribosomal protein neosynthesis. Its premature arrest by the RNA Pol I inhibitor CX-5461 targeted the proliferation of immature erythroblasts. p53 was activated spontaneously or in response to CX-5461, concomitant to ribosome biogenesis arrest, and drove a transcriptional program in which genes involved in cell cycle-arrested, negative regulation of apoptosis, and DNA damage response were upregulated. RNA Pol I transcriptional stress resulted in nucleolar disruption and activation of the ATR-CHK1-p53 pathway. Our results imply that the timing of ribosome biogenesis extinction and p53 activation is crucial for erythroid development. In ribosomopathies in which ribosome availability is altered by unbalanced production of ribosomal proteins, the threshold downregulation of ribosome biogenesis could be prematurely reached and, together with pathological p53 activation, prevents a normal expansion of erythroid progenitors.
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4
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Giraud G, Kolovos P, Boltsis I, van Staalduinen J, Guyot B, Weiss-Gayet M, IJcken WV, Morlé F, Grosveld F. Interplay between FLI-1 and the LDB1 complex in murine erythroleukemia cells and during megakaryopoiesis. iScience 2021; 24:102210. [PMID: 33733070 PMCID: PMC7940982 DOI: 10.1016/j.isci.2021.102210] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2019] [Revised: 12/22/2020] [Accepted: 02/17/2021] [Indexed: 11/29/2022] Open
Abstract
Transcription factors are key players in a broad range of cellular processes such as cell-fate decision. Understanding how they act to control these processes is of critical importance for therapy purposes. FLI-1 controls several hematopoietic lineage differentiation including megakaryopoiesis and erythropoiesis. Its aberrant expression is often observed in cancer and is associated with poor prognosis. We showed that FLI-1 interacts with the LDB1 complex, which also plays critical roles in erythropoiesis and megakaryopoiesis. In this study, we aimed to unravel how FLI-1 and the LDB1 complex act together in murine erythroleukemia cells and in megakaryocyte. Combining omics techniques, we show that FLI-1 enables the recruitment of the LDB1 complex to regulatory sequences of megakaryocytic genes and to enhancers. We show as well for the first time that FLI-1 is able to modulate the 3D chromatin organization by promoting chromatin looping between enhancers and promoters most likely through the LDB1 complex. FLI-1 is important for the recruitment of the LDB1 complex FLI-1 is important for chromatin looping FLI-1 and the LDB1 complex co-regulate megakaryopoiesis
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Affiliation(s)
- Guillaume Giraud
- Department of Cell Biology, Erasmus Medical Centre, 3015CN Rotterdam, the Netherlands
| | - Petros Kolovos
- Department of Molecular Biology and Genetics, Democritus University of Thrace, Alexandroupolis 68100, Greece
| | - Ilias Boltsis
- Department of Cell Biology, Erasmus Medical Centre, 3015CN Rotterdam, the Netherlands
| | - Jente van Staalduinen
- Department of Cell Biology, Erasmus Medical Centre, 3015CN Rotterdam, the Netherlands
| | - Boris Guyot
- CNRS UMR5286, Centre de Recherche en Cancérologie de Lyon, Lyon, France.,Inserm U1052, Centre de Recherche en Cancérologie de Lyon, Lyon, France.,Université de Lyon, Lyon, France.,Department of Immunity, Virus and Microenvironment, Lyon, France
| | - Michele Weiss-Gayet
- Institut NeuroMyoGène, CNRS UMR 5310 - INSERM U1217 - Université de Lyon - Université Claude Bernard Lyon 1, Lyon, France
| | - Wilfred van IJcken
- Biomics Center, Erasmus University Medical Center, 3015CN Rotterdam, the Netherlands
| | - François Morlé
- Institut NeuroMyoGène, CNRS UMR 5310 - INSERM U1217 - Université de Lyon - Université Claude Bernard Lyon 1, Lyon, France
| | - Frank Grosveld
- Department of Cell Biology, Erasmus Medical Centre, 3015CN Rotterdam, the Netherlands
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5
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Ribosomes: An Exciting Avenue in Stem Cell Research. Stem Cells Int 2020; 2020:8863539. [PMID: 32695182 PMCID: PMC7362291 DOI: 10.1155/2020/8863539] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2020] [Revised: 06/12/2020] [Accepted: 06/16/2020] [Indexed: 02/07/2023] Open
Abstract
Stem cell research has focused on genomic studies. However, recent evidence has indicated the involvement of epigenetic regulation in determining the fate of stem cells. Ribosomes play a crucial role in epigenetic regulation, and thus, we focused on the role of ribosomes in stem cells. Majority of living organisms possess ribosomes that are involved in the translation of mRNA into proteins and promote cellular proliferation and differentiation. Ribosomes are stable molecular machines that play a role with changes in the levels of RNA during translation. Recent research suggests that specific ribosomes actively regulate gene expression in multiple cell types, such as stem cells. Stem cells have the potential for self-renewal and differentiation into multiple lineages and, thus, require high efficiency of translation. Ribosomes induce cellular transdifferentiation and reprogramming, and disrupted ribosome synthesis affects translation efficiency, thereby hindering stem cell function leading to cell death and differentiation. Stem cell function is regulated by ribosome-mediated control of stem cell-specific gene expression. In this review, we have presented a detailed discourse on the characteristics of ribosomes in stem cells. Understanding ribosome biology in stem cells will provide insights into the regulation of stem cell function and cellular reprogramming.
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Song J, Yuan C, Yang J, Liu T, Yao Y, Xiao X, Gajendran B, Xu D, Li Y, Wang C, Liu W, Wen M, Spaner D, Filmus J, Zacksenhaus E, Zhang Y, Hao X, Ben‐David Y. Novel flavagline‐like compounds with potent Fli‐1 inhibitory activity suppress diverse types of leukemia. FEBS J 2018; 285:4631-4645. [DOI: 10.1111/febs.14690] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2018] [Revised: 10/15/2018] [Accepted: 10/31/2018] [Indexed: 12/19/2022]
Affiliation(s)
- Jialei Song
- The Laboratory of Cell Biochemistry and Topogenic Regulation College of Bioengineering and Faculty of Sciences Chongqing University China
- State Key Laboratory for Functions and Applications of Medicinal Plants Guizhou Medical University Guiyang China
- The Key Laboratory of Chemistry for Natural Products of Guizhou Province and Chinese Academic of Sciences Guiyang China
| | - Chunmao Yuan
- State Key Laboratory for Functions and Applications of Medicinal Plants Guizhou Medical University Guiyang China
- The Key Laboratory of Chemistry for Natural Products of Guizhou Province and Chinese Academic of Sciences Guiyang China
| | - Jue Yang
- State Key Laboratory for Functions and Applications of Medicinal Plants Guizhou Medical University Guiyang China
- The Key Laboratory of Chemistry for Natural Products of Guizhou Province and Chinese Academic of Sciences Guiyang China
| | - Tangjingjun Liu
- State Key Laboratory for Functions and Applications of Medicinal Plants Guizhou Medical University Guiyang China
- The Key Laboratory of Chemistry for Natural Products of Guizhou Province and Chinese Academic of Sciences Guiyang China
| | - Yao Yao
- State Key Laboratory for Functions and Applications of Medicinal Plants Guizhou Medical University Guiyang China
- The Key Laboratory of Chemistry for Natural Products of Guizhou Province and Chinese Academic of Sciences Guiyang China
| | - Xiao Xiao
- State Key Laboratory for Functions and Applications of Medicinal Plants Guizhou Medical University Guiyang China
- The Key Laboratory of Chemistry for Natural Products of Guizhou Province and Chinese Academic of Sciences Guiyang China
| | - Babu Gajendran
- State Key Laboratory for Functions and Applications of Medicinal Plants Guizhou Medical University Guiyang China
- The Key Laboratory of Chemistry for Natural Products of Guizhou Province and Chinese Academic of Sciences Guiyang China
| | - Dahai Xu
- Department of Anatomy Norman Bethune College of Medicine Jilin University Changchun China
| | - You‐Jun Li
- Department of Anatomy Norman Bethune College of Medicine Jilin University Changchun China
| | - Chunlin Wang
- State Key Laboratory for Functions and Applications of Medicinal Plants Guizhou Medical University Guiyang China
- The Key Laboratory of Chemistry for Natural Products of Guizhou Province and Chinese Academic of Sciences Guiyang China
| | - Wuling Liu
- State Key Laboratory for Functions and Applications of Medicinal Plants Guizhou Medical University Guiyang China
- The Key Laboratory of Chemistry for Natural Products of Guizhou Province and Chinese Academic of Sciences Guiyang China
| | - Min Wen
- State Key Laboratory for Functions and Applications of Medicinal Plants Guizhou Medical University Guiyang China
- The Key Laboratory of Chemistry for Natural Products of Guizhou Province and Chinese Academic of Sciences Guiyang China
| | - David Spaner
- Biology Platform Sunnybrook Research Institute Toronto Canada
| | - Jorge Filmus
- Biology Platform Sunnybrook Research Institute Toronto Canada
| | - Eldad Zacksenhaus
- Department of Medicine University of Toronto Canada
- Division of Advanced Diagnostics Toronto General Research Institute University Health Network Toronto Canada
| | - Yiguo Zhang
- The Laboratory of Cell Biochemistry and Topogenic Regulation College of Bioengineering and Faculty of Sciences Chongqing University China
| | - Xiaojiang Hao
- State Key Laboratory for Functions and Applications of Medicinal Plants Guizhou Medical University Guiyang China
- The Key Laboratory of Chemistry for Natural Products of Guizhou Province and Chinese Academic of Sciences Guiyang China
| | - Yaacov Ben‐David
- State Key Laboratory for Functions and Applications of Medicinal Plants Guizhou Medical University Guiyang China
- The Key Laboratory of Chemistry for Natural Products of Guizhou Province and Chinese Academic of Sciences Guiyang China
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7
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Shen L, Tenzer S, Hess M, Distler U, Tubbe I, Montermann E, Schimmer S, Dittmer U, Grabbe S, Bros M. Friend virus limits adaptive cellular immune responses by imprinting a maturation-resistant and T helper type 2-biased immunophenotype in dendritic cells. PLoS One 2018; 13:e0192541. [PMID: 29425215 PMCID: PMC5806892 DOI: 10.1371/journal.pone.0192541] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2017] [Accepted: 01/25/2018] [Indexed: 12/28/2022] Open
Abstract
The murine Friend virus (FV) retrovirus model has been widely used to study anti-viral immune responses, and virus-induced cancer. Here we analyzed FV immune evasion mechanisms on the level of dendritic cells (DC) essential for the induction of primary adaptive immune responses. Comparative quantitative proteome analysis of FV-infected DC (FV-DC) of different genotypes (BALB/c, C57BL/6) and non-infected DC revealed numerous genotype-independently regulated proteins rergulating metabolic activity, cytoskeletal rearrangements, and antigen processing/presentation. These alterations may promote virion production in FV-DC. Stimulation of FV-DC with LPS resulted in strongly enhanced IL-10 production which was partially responsible for their attenuated T cell (CD4+, CD8+) stimulatory capacity. Stimulated FV-DC induced less IFN-γ production in T cells required for cellular anti-viral responses, but more T helper cell type 2 (Th2)-associated cytokines (IL-4, IL-5, IL-13). We conclude that FV reprograms DC to promote viral spreading and immune deviation by imprinting a largely maturation-resistant, Th2-biased immunophenotype.
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Affiliation(s)
- Limei Shen
- Department of Dermatology, University Medical Center, Mainz, Germany
| | - Stefan Tenzer
- Institute of Immunology, University Medical Center, Mainz, Germany
| | - Moritz Hess
- Institute for Medical Biometry, Epidemiology and Informatics, University Medical Center, Mainz, Germany
| | - Ute Distler
- Institute of Immunology, University Medical Center, Mainz, Germany
| | - Ingrid Tubbe
- Department of Dermatology, University Medical Center, Mainz, Germany
| | - Evelyn Montermann
- Department of Dermatology, University Medical Center, Mainz, Germany
| | - Simone Schimmer
- Institute for Virology of the University Hospital Essen, University of Duisburg-Essen, Essen, Germany
| | - Ulf Dittmer
- Institute for Virology of the University Hospital Essen, University of Duisburg-Essen, Essen, Germany
| | - Stephan Grabbe
- Department of Dermatology, University Medical Center, Mainz, Germany
- * E-mail:
| | - Matthias Bros
- Department of Dermatology, University Medical Center, Mainz, Germany
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8
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Vecchiarelli-Federico LM, Liu T, Yao Y, Gao Y, Li Y, Li YJ, Ben-David Y. Fli-1 overexpression in erythroleukemic cells promotes erythroid de-differentiation while Spi-1/PU.1 exerts the opposite effect. Int J Oncol 2017; 51:456-466. [PMID: 28586009 PMCID: PMC5505126 DOI: 10.3892/ijo.2017.4027] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2017] [Accepted: 05/23/2017] [Indexed: 01/21/2023] Open
Abstract
The ETS transcription factors play a critical role during hematopoiesis. In F-MuLV-induced erythroleukemia, Fli-1 insertional activation producing high expression of this transcription factor required to promote proliferation. How deregulated Fli-1 expression alters the balance between erythroid differentiation and proliferation is unknown. To address this issue, we exogenously overexpressed Fli-1 in an erythroleukemic cell harboring activation of spi-1/PU.1, another ETS gene involved in erythroleukemogenesis. While the proliferation in culture remains unaffected, Fli-1 overexpression imparts morphological and immunohistochemical characteristics of immature erythroid progenitors. Fli-1 overexpression in erythroleukemic cells increased the numbers of erythroid colonies on methylcellulose and reduced tumorigenicity as evidenced by increase latency of erythroleukemogenesis in mice inoculated with these cells. Although all transplanted mice developed enlargement of the spleen and liver due to leukemic infiltration, Fli-1 overexpression altered the hematopoietic phenotype, significantly increasing the expression of regulatory hematopoietic genes cKIT, SCA-1, CD41 and CD71. In contrast, expression of Spi-1/PU.1 in a Fli-1 producing erythroleukemia cell line in which fli-1 is activated, resulted in increased proliferation through activation of growth promoting proteins MAPK, AKT, cMYC and JAK2. Importantly, these progenitors express high levels of markers such as CD71 and TER119 associated with more mature erythroid cells. Thus, Fli-1 overexpression induces a de-differentiation program by reverting CFU-E to BFU-E erythroid progenitor activity, while Spi-1/PU.1 promoting maturation from BFU-E to CFU-E.
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Affiliation(s)
| | - Tangjingjun Liu
- The Key Laboratory of Chemistry for Natural Products of Guizhou Province and Chinese Academic of Sciences, Guiyang, Guizhou 550014, P.R. China
| | - Yao Yao
- The Key Laboratory of Chemistry for Natural Products of Guizhou Province and Chinese Academic of Sciences, Guiyang, Guizhou 550014, P.R. China
| | - Yuanyuan Gao
- Department of Anatomy, College of Basic Medical Sciences, Jilin University, Changchun, Jilin 130021, P.R. China
| | - Yanmei Li
- Molecular and Cellular Biology, Sunnybrook Health Sciences Centre, Toronto, Ontario M4N 3M5, Canada
| | - You-Jun Li
- Department of Anatomy, College of Basic Medical Sciences, Jilin University, Changchun, Jilin 130021, P.R. China
| | - Yaacov Ben-David
- The Key Laboratory of Chemistry for Natural Products of Guizhou Province and Chinese Academic of Sciences, Guiyang, Guizhou 550014, P.R. China
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9
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Amanatiadou EP, Papadopoulos GL, Strouboulis J, Vizirianakis IS. GATA1 and PU.1 Bind to Ribosomal Protein Genes in Erythroid Cells: Implications for Ribosomopathies. PLoS One 2015; 10:e0140077. [PMID: 26447946 PMCID: PMC4598024 DOI: 10.1371/journal.pone.0140077] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2015] [Accepted: 09/21/2015] [Indexed: 12/15/2022] Open
Abstract
The clear connection between ribosome biogenesis dysfunction and specific hematopoiesis-related disorders prompted us to examine the role of critical lineage-specific transcription factors in the transcriptional regulation of ribosomal protein (RP) genes during terminal erythroid differentiation. By applying EMSA and ChIP methodologies in mouse erythroleukemia cells we show that GATA1 and PU.1 bind in vitro and in vivo the proximal promoter region of the RPS19 gene which is frequently mutated in Diamond-Blackfan Anemia. Moreover, ChIPseq data analysis also demonstrates that several RP genes are enriched as potential GATA1 and PU.1 gene targets in mouse and human erythroid cells, with GATA1 binding showing an association with higher ribosomal protein gene expression levels during terminal erythroid differentiation in human and mouse. Our results suggest that RP gene expression and hence balanced ribosome biosynthesis may be specifically and selectively regulated by lineage specific transcription factors during hematopoiesis, a finding which may be clinically relevant to ribosomopathies.
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Affiliation(s)
- Elsa P. Amanatiadou
- Laboratory of Pharmacology, Department of Pharmaceutical Sciences, Aristotle University of Thessaloniki, Thessaloniki, Greece
| | - Giorgio L. Papadopoulos
- Division of Molecular Oncology, Biomedical Sciences Research Center "Alexander Fleming", Vari, Greece
| | - John Strouboulis
- Division of Molecular Oncology, Biomedical Sciences Research Center "Alexander Fleming", Vari, Greece
- * E-mail: (JS); (ISV)
| | - Ioannis S. Vizirianakis
- Laboratory of Pharmacology, Department of Pharmaceutical Sciences, Aristotle University of Thessaloniki, Thessaloniki, Greece
- * E-mail: (JS); (ISV)
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10
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Cai X, Gao L, Teng L, Ge J, Oo ZM, Kumar AR, Gilliland DG, Mason PJ, Tan K, Speck NA. Runx1 Deficiency Decreases Ribosome Biogenesis and Confers Stress Resistance to Hematopoietic Stem and Progenitor Cells. Cell Stem Cell 2015; 17:165-77. [PMID: 26165925 DOI: 10.1016/j.stem.2015.06.002] [Citation(s) in RCA: 154] [Impact Index Per Article: 17.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2014] [Revised: 04/05/2015] [Accepted: 06/05/2015] [Indexed: 12/13/2022]
Abstract
The transcription factor RUNX1 is frequently mutated in myelodysplastic syndrome and leukemia. RUNX1 mutations can be early events, creating preleukemic stem cells that expand in the bone marrow. Here we show, counterintuitively, that Runx1-deficient hematopoietic stem and progenitor cells (HSPCs) have a slow growth, low biosynthetic, small cell phenotype and markedly reduced ribosome biogenesis (Ribi). The reduced Ribi involved decreased levels of rRNA and many mRNAs encoding ribosome proteins. Runx1 appears to directly regulate Ribi; Runx1 is enriched on the promoters of genes encoding ribosome proteins and binds the rDNA repeats. Runx1-deficient HSPCs have lower p53 levels, reduced apoptosis, an attenuated unfolded protein response, and accordingly are resistant to genotoxic and ER stress. The low biosynthetic activity and corresponding stress resistance provides a selective advantage to Runx1-deficient HSPCs, allowing them to expand in the bone marrow and outcompete normal HSPCs.
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Affiliation(s)
- Xiongwei Cai
- Abramson Family Cancer Research Institute, Institute for Regenerative Medicine and Department of Cell and Developmental Biology, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Long Gao
- Department of Biomedical Engineering, University of Iowa, Iowa City, IA 52242, USA
| | - Li Teng
- Department of Internal Medicine, University of Iowa, Iowa City, IA 52242, USA
| | - Jingping Ge
- Department of Pediatrics, The Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA
| | - Zaw Min Oo
- Abramson Family Cancer Research Institute, Institute for Regenerative Medicine and Department of Cell and Developmental Biology, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Ashish R Kumar
- Division of Bone Marrow Transplantation and Immune Deficiency, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229, USA
| | - D Gary Gilliland
- Abramson Family Cancer Research Institute, Institute for Regenerative Medicine and Department of Cell and Developmental Biology, University of Pennsylvania, Philadelphia, PA 19104, USA; Abramson Family Cancer Research Institute and Department of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Philip J Mason
- Department of Pediatrics, The Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA
| | - Kai Tan
- Department of Internal Medicine, University of Iowa, Iowa City, IA 52242, USA
| | - Nancy A Speck
- Abramson Family Cancer Research Institute, Institute for Regenerative Medicine and Department of Cell and Developmental Biology, University of Pennsylvania, Philadelphia, PA 19104, USA.
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11
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Giraud G, Stadhouders R, Conidi A, Dekkers DHW, Huylebroeck D, Demmers JAA, Soler E, Grosveld FG. NLS-tagging: an alternative strategy to tag nuclear proteins. Nucleic Acids Res 2014; 42:gku869. [PMID: 25260593 PMCID: PMC4245968 DOI: 10.1093/nar/gku869] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
The characterization of transcription factor complexes and their binding sites in the genome by affinity purification has yielded tremendous new insights into how genes are regulated. The affinity purification requires either the use of antibodies raised against the factor of interest itself or by high-affinity binding of a C- or N-terminally added tag sequence to the factor. Unfortunately, fusing extra amino acids to the termini of a factor can interfere with its biological function or the tag may be inaccessible inside the protein. Here, we describe an effective solution to that problem by integrating the ‘tag’ close to the nuclear localization sequence domain of the factor. We demonstrate the effectiveness of this approach with the transcription factors Fli-1 and Irf2bp2, which cannot be tagged at their extremities without loss of function. This resulted in the identification of novel proteins partners and a new hypothesis on the contribution of Fli-1 to hematopoiesis.
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Affiliation(s)
- Guillaume Giraud
- Department of Cell Biology, Erasmus Medical Center, Faculty building, PO Box 2040, 3000 CA Rotterdam, The Netherlands
| | - Ralph Stadhouders
- Department of Cell Biology, Erasmus Medical Center, Faculty building, PO Box 2040, 3000 CA Rotterdam, The Netherlands
| | - Andrea Conidi
- Department of Cell Biology, Erasmus Medical Center, Faculty building, PO Box 2040, 3000 CA Rotterdam, The Netherlands
| | - Dick H W Dekkers
- Proteomics Center, Erasmus University Medical Center, Faculty building, PO Box 2040, 3000 CA Rotterdam, The Netherlands
| | - Danny Huylebroeck
- Department of Cell Biology, Erasmus Medical Center, Faculty building, PO Box 2040, 3000 CA Rotterdam, The Netherlands Laboratory of Molecular Biology (Celgen), Department of Development and Regeneration, KU Leuven, Herestraat 49, B-3000 Leuven, Belgium
| | - Jeroen A A Demmers
- Proteomics Center, Erasmus University Medical Center, Faculty building, PO Box 2040, 3000 CA Rotterdam, The Netherlands
| | - Eric Soler
- Department of Cell Biology, Erasmus Medical Center, Faculty building, PO Box 2040, 3000 CA Rotterdam, The Netherlands Laboratory of Hematopoiesis and Leukemic Stem Cells (LSHL), CEA/INSERM U967, Fontenay-aux-Roses, France Center for Biomedical Genetics and Medical Epigenetics Consortium, Erasmus Medical Center, Faculty building, PO Box 2040, 3000 CA Rotterdam, The Netherlands
| | - Frank G Grosveld
- Department of Cell Biology, Erasmus Medical Center, Faculty building, PO Box 2040, 3000 CA Rotterdam, The Netherlands Center for Biomedical Genetics and Medical Epigenetics Consortium, Erasmus Medical Center, Faculty building, PO Box 2040, 3000 CA Rotterdam, The Netherlands Center for Biomedical Genetics, Erasmus Medical Center, Faculty building, PO Box 2040, 3000 CA Rotterdam, The Netherlands
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12
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The ets transcription factor Fli-1 in development, cancer and disease. Oncogene 2014; 34:2022-31. [PMID: 24909161 PMCID: PMC5028196 DOI: 10.1038/onc.2014.162] [Citation(s) in RCA: 94] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2014] [Revised: 05/03/2014] [Accepted: 05/04/2014] [Indexed: 12/13/2022]
Abstract
Friend Leukemia Virus Induced erythroleukemia-1 (Fli-1), an ETS transcription factor, was isolated a quarter century ago through a retrovirus mutagenesis screen. Fli-1 has since been recognized to play critical roles in normal development and homeostasis. For example, it transcriptionally regulates genes that drive normal hematopoiesis and vasculogenesis. Indeed, Fli-1 is one of 10 key regulators of hematopoietic stem/progenitor cell maintenance and differentiation. Aberrant expression of Fli-1 also underlies a number of virally induced leukemias, including Friend virus-induced erythroleukemia and various types of human cancers, and it is the target of chromosomal translocations in childhood Ewing’s sarcoma. Abnormal expression of Fli-1 is important in the aetiology of auto-immune diseases such as Systemic Lupus Erythematosus (SLE) and Systemic Sclerosis (SSc). These studies establish Fli-1 as a strong candidate for drug development. Despite difficulties in targeting transcription factors, recent studies identified small molecule inhibitors for Fli-1. Here we review past and ongoing research on Fli-1 with emphasis on its mechanistic function in autoimmune disease and malignant transformation. The significance of identifying Fli-1 inhibitors and their clinical applications for treatment of disease and cancer with deregulated Fli-1 expression are discussed.
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Mizutani N, Kobayashi M, Sobue S, Ichihara M, Ito H, Tanaka K, Iwaki S, Fujii S, Ito Y, Tamiya-Koizumi K, Takagi A, Kojima T, Naoe T, Suzuki M, Nakamura M, Banno Y, Nozawa Y, Murate T. Sphingosine kinase 1 expression is downregulated during differentiation of Friend cells due to decreased c-MYB. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2013; 1833:1006-16. [DOI: 10.1016/j.bbamcr.2013.01.001] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/07/2012] [Revised: 12/23/2012] [Accepted: 01/02/2013] [Indexed: 12/19/2022]
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Identification of KAP-1-associated complexes negatively regulating the Ey and β-major globin genes in the β-globin locus. J Proteomics 2013; 80:132-44. [PMID: 23291531 DOI: 10.1016/j.jprot.2012.12.014] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2012] [Revised: 12/11/2012] [Accepted: 12/22/2012] [Indexed: 10/27/2022]
Abstract
Deregulations of erythroid differentiation may lead to erythroleukemia and other hemoglobinopathies, yet the molecular mechanisms underlying these events are not fully understood. Here, we found that KAP-1-associated complexes contribute to the regulation of the β-globin locus, the key events of erythroid differentiation. We show that RNAi-mediated knockdown of KAP-1 in mouse erythroleukemia (MEL) cells increases expression of the Ey and β-major globin genes during hexamethylenebisacetamide (HMBA) induced differentiation process. This indicates that at least part of KAP-1-associated complexes negatively regulates β-globin gene expression during definitive erythroid differentiation. ChIP-PCR analysis revealed that one or more KAP-1-associated complexes are targeted to the promoter region of the Ey and beta-major globin genes. Since KAP-1 is only a scaffold molecule, there must be some transcriptional regulators allowing its targeted recruitment to the β-globin locus. To further discover these novel regulators, proteins interacting with KAP-1 were isolated by endogenous immunoprecipitation and identified by LC-ESI-MS/MS. Among the proteins identified, MafK and Zfp445 were studied further. We found that KAP-1 may contribute to the repression of Ey and β-major globin gene transcription through recruitment to the promoters of these two genes, mediated by the interaction of KAP-1 with either Zfp445 or MafK, respectively.
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Kayali S, Giraud G, Morlé F, Guyot B. Spi-1, Fli-1 and Fli-3 (miR-17-92) oncogenes contribute to a single oncogenic network controlling cell proliferation in friend erythroleukemia. PLoS One 2012; 7:e46799. [PMID: 23056458 PMCID: PMC3466182 DOI: 10.1371/journal.pone.0046799] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2012] [Accepted: 09/07/2012] [Indexed: 01/07/2023] Open
Abstract
Clonal erythroleukemia developing in susceptible mice infected by Friend virus complex are associated with highly recurrent proviral insertions at one of three loci called Spi-1, Fli-1 or Fli-3, leading to deregulated expression of oncogenic Spi-1 or Fli-1 transcription factors or miR-17-92 miRNA cluster, respectively. Deregulated expression of each of these three oncogenes has been independently shown to contribute to cell proliferation of erythroleukemic clones. Previous studies showed a close relationship between Spi-1 and Fli-1, which belong to the same ETS family, Spi-1 activating fli-1 gene, and both Spi-1 and Fli-1 activating multiple common target genes involved in ribosome biogenesis. In this study, we demonstrated that Spi-1 and Fli-1 are also involved in direct miR-17-92 transcriptional activation through their binding to a conserved ETS binding site in its promoter. Moreover, we demonstrated that physiological re-expression of exogenous miR-17 and miR-20a are able to partially rescue the proliferation loss induced by Fli-1 knock-down and identified HBP1 as a target of these miRNA in erythroleukemic cells. These results establish that three of the most recurrently activated oncogenes in Friend erythroleukemia are actually involved in a same oncogenic network controlling cell proliferation. The putative contribution of a similar ETS-miR-17-92 network module in other normal or pathological proliferative contexts is discussed.
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Affiliation(s)
- Samer Kayali
- CGPhiMC, CNRS UMR5534, Université Claude Bernard Lyon1, Lyon, France
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Important genes in the pathogenesis of 5q- syndrome and their connection with ribosomal stress and the innate immune system pathway. LEUKEMIA RESEARCH AND TREATMENT 2012; 2012:179402. [PMID: 23213547 PMCID: PMC3504201 DOI: 10.1155/2012/179402] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/25/2011] [Revised: 11/06/2011] [Accepted: 11/14/2011] [Indexed: 01/10/2023]
Abstract
Myelodysplastic syndrome (MDS) with interstitial deletion of a segment of the long arm of chromosome 5q [del(5q)] is characterized by bone marrow erythroid hyperplasia, atypical megakaryocytes, thrombocythemia, refractory anemia, and low risk of progression to acute myeloid leukemia (AML) compared with other types of MDS. The long arm of chromosome 5 contains two distinct commonly deleted regions (CDRs). The more distal CDR lies in 5q33.1 and contains 40 protein-coding genes and genes coding microRNAs (miR-143, miR-145). In 5q-syndrome one allele is deleted that accounts for haploinsufficiency of these genes. The mechanism of erythroid failure appears to involve the decreased expression of the ribosomal protein S14 (RPS14) gene and the upregulation of the p53 pathway by ribosomal stress. Friend leukemia virus integration 1 (Fli1) is one of the target genes of miR145. Increased Fli1 expression enables effective megakaryopoiesis in 5q-syndrome.
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Nivon M, Abou-Samra M, Richet E, Guyot B, Arrigo AP, Kretz-Remy C. NF-κB regulates protein quality control after heat stress through modulation of the BAG3-HspB8 complex. J Cell Sci 2012; 125:1141-51. [PMID: 22302993 DOI: 10.1242/jcs.091041] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
We previously found that the NF-κB transcription factor is activated during the recovery period after heat shock; moreover, we demonstrated that NF-κB is essential for cell survival after heat shock by activating autophagy, a mechanism that probably helps the cell to cope with hyperthermic stress through clearance of damaged proteins. In this study, we analyze the involvement of NF-κB in basal and heat-stress-induced protein quality control, by comparing the level of multiubiquitylated and/or aggregated proteins, and proteasome and autophagic activity in NF-κB-competent and NF-κB-incompetent cells. We show that NF-κB has only a minor role in basal protein quality control, where it modulates autophagosome maturation. By contrast, NF-κB is shown to be a key player in protein quality control after hyperthermia. Indeed, NF-κB-incompetent cells show highly increased levels of multiubiquitylated and/or aggregated proteins and aggresome clearance defects; a phenotype that disappears when NF-κB activity is restored to normal. We demonstrate that during heat shock recovery NF-κB activates selective removal of misfolded or aggregated proteins--a process also called 'aggrephagy'--by controlling the expression of BAG3 and HSPB8 and by modulating the level of the BAG3-HspB8 complex. Thus NF-κB-mediated increase in the level of the BAG3-HspB8 complex leads to upregulation of aggrephagy and clearance of irreversibly damaged proteins and might increase cell survival in conditions of hyperthermia.
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Li YJ, Zhao X, Vecchiarelli-Federico LM, Li Y, Datti A, Cheng Y, Ben-David Y. Drug-mediated inhibition of Fli-1 for the treatment of leukemia. Blood Cancer J 2012; 2:e54. [PMID: 22829238 PMCID: PMC3270256 DOI: 10.1038/bcj.2011.52] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2011] [Accepted: 12/12/2011] [Indexed: 12/24/2022] Open
Abstract
The Ets transcription factor, Fli-1 is activated in murine erythroleukemia and overexpressed in various human malignancies including Ewing's sarcoma, induced by the oncogenic fusion protein EWS/Fli-1. Recent studies by our group and others have demonstrated that Fli-1 plays a key role in tumorigenesis, and disrupting its oncogenic function may serve as a potential treatment option for malignancies associated with its overexpression. Herein, we describe the discovery of 30 anti-Fli-1 compounds, characterized into six functional groups. Treatment of murine and human leukemic cell lines with select compounds inhibits Fli-1 protein or mRNA expression, resulting in proliferation arrest and apoptosis. This anti-cancer effect was mediated, at least in part through direct inhibition of Fli-1 function, as anti-Fli-1 drug treatment inhibited Fli-1 DNA binding to target genes, such as SHIP-1 and gata-1, governing hematopoietic differentiation and proliferation. Furthermore, treatment with select Fli-1 inhibitors revealed a positive relationship between the loss of DNA-binding activity and Fli-1 phosphorylation. Accordingly, anti-Fli-1 drug treatment significantly inhibited leukemogenesis in a murine erythroleukemia model overexpressing Fli-1. This study demonstrates the ability of this drug-screening strategy to isolate effective anti-Fli-1 inhibitors and highlights their potential use for the treatment of malignancies overexpressing this oncogene.
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Abstract
Within the decade following the demonstration that mutations in the RPS19 gene can lead to Diamond-Blackfan anemia (DBA), this disease has become a paradigm for an emerging group of pathologies linked to defects in ribosome biogenesis. DBA patients exhibit abnormal pre-rRNA maturation patterns and the majority bear mutations in one of several ribosomal protein genes that encode structural components of the ribosome essential for the correct assembly of the ribosomal subunits. Extensive study of the most frequently mutated gene, RPS19, has shown that mutations prevent the assembly of the ribosomal protein into forming pre-ribosomal particles. This defect in ribosome production triggers nucleolar stress pathways, the activation of which appears to be central to pathophysiological mechanisms. Why mutations in ribosomal protein genes so strongly and specifically affect erythropoiesis in DBA remains a challenging question, especially given the fact that defects in genes encoding nonstructural ribosome biogenesis factors have been shown to cause diseases other than DBA. A major problem in understanding the pathophysiological mechanisms in DBA remains the lack of a suitable animal model. Despite this, considerable strides have been made over that past few years demonstrating that several factors involved in the synthesis of ribosomes are targets of disease-causing mutations.
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Affiliation(s)
- Steven R Ellis
- Department of Biochemistry and Molecular Biology, University of Louisville, Louisville, KY 40292, USA.
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Inducible Fli-1 gene deletion in adult mice modifies several myeloid lineage commitment decisions and accelerates proliferation arrest and terminal erythrocytic differentiation. Blood 2010; 116:4795-805. [PMID: 20733157 DOI: 10.1182/blood-2010-02-270405] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
This study investigated the role of the ETS transcription factor Fli-1 in adult myelopoiesis using new transgenic mice allowing inducible Fli-1 gene deletion. Fli-1 deletion in adult induced mild thrombocytopenia associated with a drastic decrease in large mature megakaryocytes number. Bone marrow bipotent megakaryocytic-erythrocytic progenitors (MEPs) increased by 50% without increase in erythrocytic and megakaryocytic common myeloid progenitor progeny, suggesting increased production from upstream stem cells. These MEPs were almost unable to generate pure colonies containing large mature megakaryocytes, but generated the same total number of colonies mainly identifiable as erythroid colonies containing a reduced number of more differentiated cells. Cytological and fluorescence-activated cell sorting analyses of MEP progeny in semisolid and liquid cultures confirmed the drastic decrease in large mature megakaryocytes but revealed a surprisingly modest (50%) reduction of CD41-positive cells indicating the persistence of a megakaryocytic commitment potential. Symmetrical increase and decrease of monocytic and granulocytic progenitors were also observed in the progeny of purified granulocytic-monocytic progenitors and common myeloid progenitors. In summary, this study indicates that Fli-1 controls several lineages commitment decisions at the stem cell, MEP, and granulocytic-monocytic progenitor levels, stimulates the proliferation of committed erythrocytic progenitors at the expense of their differentiation, and is a major regulator of late stages of megakaryocytic differentiation.
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Mehlitz A, Banhart S, Mäurer AP, Kaushansky A, Gordus AG, Zielecki J, MacBeath G, Meyer TF. Tarp regulates early Chlamydia-induced host cell survival through interactions with the human adaptor protein SHC1. J Cell Biol 2010; 190:143-57. [PMID: 20624904 PMCID: PMC2911661 DOI: 10.1083/jcb.200909095] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2009] [Accepted: 06/14/2010] [Indexed: 12/28/2022] Open
Abstract
Many bacterial pathogens translocate effector proteins into host cells to manipulate host cell functions. Here, we used a protein microarray comprising virtually all human SRC homology 2 (SH2) and phosphotyrosine binding domains to comprehensively and quantitatively assess interactions between host cell proteins and the early phase Chlamydia trachomatis effector protein translocated actin-recruiting phosphoprotein (Tarp), which is rapidly tyrosine phosphorylated upon host cell entry. We discovered numerous novel interactions between human SH2 domains and phosphopeptides derived from Tarp. The adaptor protein SHC1 was among Tarp's strongest interaction partners. Transcriptome analysis of SHC1-dependent gene regulation during infection indicated that SHC1 regulates apoptosis- and growth-related genes. SHC1 knockdown sensitized infected host cells to tumor necrosis factor-induced apoptosis. Collectively, our findings reveal a critical role for SHC1 in early C. trachomatis-induced cell survival and suggest that Tarp functions as a multivalent phosphorylation-dependent signaling hub that is important during the early phase of chlamydial infection.
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Affiliation(s)
- Adrian Mehlitz
- Department of Molecular Biology, Max Planck Institute for Infection Biology, 10117 Berlin, Germany
- Department of Microbiology, Biocenter, University of Würzburg, 97074 Würzburg, Germany
| | - Sebastian Banhart
- Department of Molecular Biology, Max Planck Institute for Infection Biology, 10117 Berlin, Germany
| | - André P. Mäurer
- Department of Molecular Biology, Max Planck Institute for Infection Biology, 10117 Berlin, Germany
| | - Alexis Kaushansky
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA 02138
| | - Andrew G. Gordus
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA 02138
| | - Julia Zielecki
- Department of Molecular Biology, Max Planck Institute for Infection Biology, 10117 Berlin, Germany
| | - Gavin MacBeath
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA 02138
| | - Thomas F. Meyer
- Department of Molecular Biology, Max Planck Institute for Infection Biology, 10117 Berlin, Germany
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The inositol phosphatase SHIP-1 is negatively regulated by Fli-1 and its loss accelerates leukemogenesis. Blood 2010; 116:428-36. [PMID: 20445019 DOI: 10.1182/blood-2009-10-250217] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
The activation of Fli-1, an Ets transcription factor, is the critical genetic event in Friend murine leukemia virus (F-MuLV)-induced erythroleukemia. Fli-1 overexpression leads to erythropoietin-dependent erythroblast proliferation, enhanced survival, and inhibition of terminal differentiation, through activation of the Ras pathway. However, the mechanism by which Fli-1 activates this signal transduction pathway has yet to be identified. Down-regulation of the Src homology 2 (SH2) domain-containing inositol-5-phosphatase-1 (SHIP-1) is associated with erythropoietin-stimulated erythroleukemic cells and correlates with increased proliferation of transformed cells. In this study, we have shown that F-MuLV-infected SHIP-1 knockout mice display accelerated erythroleukemia progression. In addition, RNA interference (RNAi)-mediated suppression of SHIP-1 in erythroleukemia cells activates the phosphatidylinositol 3-kinase (PI 3-K) and extracellular signal-regulated kinase/mitogen-activated protein kinase (ERK/MAPK) pathways, blocks erythroid differentiation, accelerates erythropoietin-induced proliferation, and leads to PI 3-K-dependent Fli-1 up-regulation. Chromatin immunoprecipitation and luciferase assays confirmed that Fli-1 binds directly to an Ets DNA binding site within the SHIP-1 promoter and suppresses SHIP-1 transcription. These data provide evidence to suggest that SHIP-1 is a direct Fli-1 target, SHIP-1 and Fli-1 regulate each other in a negative feedback loop, and the suppression of SHIP-1 by Fli-1 plays an important role in the transformation of erythroid progenitors by F-MuLV.
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Breig O, Théoleyre O, Douablin A, Baklouti F. Subtle distinct regulations of late erythroid molecular events by PI3K/AKT-mediated activation of Spi-1/PU.1 oncogene autoregulation loop. Oncogene 2010; 29:2807-16. [PMID: 20190819 DOI: 10.1038/onc.2010.29] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Spi-1/PU.1 oncogene is downregulated as proerythroblasts undergo terminal differentiation. Insertion of the Friend virus upstream of the Spi-1/PU.1 locus leads to the constitutive upregulation of Spi-1/PU.1, and a subsequent block in the differentiation of the affected erythroblasts. We have shown that sustained overexpression of Spi-1/PU.1 also inhibits the erythroid splicing of protein 4.1R exon 16, irrespective of chemical induction of differentiation. Here, we show a positive feedback loop that couples constitutive phosphatidylinositol 3-kinase (PI3K)/protein kinase B (AKT) signaling to high expression of Spi-1/PU.1 in Friend erythroleukemia cells. Inhibition of PI3K/AKT results in Spi-1/PU.1 downregulation in a stepwise manner and induces cell differentiation. Chromatin immunoprecipitation assays further supported the positive autoregulatory effect of Spi-1/PU.1. Mutational analysis indicated that Ser41, but not Ser148, is necessary for Spi-1/PU.1-mediated repression of hemoglobin expression, whereas both Ser residues are required for Spi-1/PU.1 inhibition of the erythroid splicing event. We further show that inhibition of the erythroid transcriptional and splicing events are strictly dependent on distinct Spi-1/PU.1 phosphorylation modifications rather than Spi-1/PU.1 expression level per se. Our data further support the fact that Spi-1/PU.1 inhibits 4.1R erythroid splicing through two different pathways, and bring new insights into the extracellular signal impact triggered by erythropoietin on late erythroid regulatory program, including pre-mRNA splicing.
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Affiliation(s)
- O Breig
- mRNA Metabolism in Normal and Pathological Cells, CGMC, CNRS, Université Lyon 1, Villeurbanne, France
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