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Melo GA, Calôba C, Brum G, Passos TO, Martinez GJ, Pereira RM. Epigenetic regulation of T cells by Polycomb group proteins. J Leukoc Biol 2022; 111:1253-1267. [DOI: 10.1002/jlb.2ri0122-039r] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2022] [Revised: 03/10/2022] [Accepted: 04/01/2022] [Indexed: 11/12/2022] Open
Affiliation(s)
- Guilherme A. Melo
- Instituto de Microbiologia Paulo de Góes, Departamento de Imunologia Universidade Federal do Rio de Janeiro Rio de Janeiro RJ Brazil
| | - Carolina Calôba
- Instituto de Microbiologia Paulo de Góes, Departamento de Imunologia Universidade Federal do Rio de Janeiro Rio de Janeiro RJ Brazil
| | - Gabrielle Brum
- Instituto de Microbiologia Paulo de Góes, Departamento de Imunologia Universidade Federal do Rio de Janeiro Rio de Janeiro RJ Brazil
| | - Thaís O. Passos
- Instituto de Microbiologia Paulo de Góes, Departamento de Imunologia Universidade Federal do Rio de Janeiro Rio de Janeiro RJ Brazil
| | - Gustavo J. Martinez
- Center for Cancer Cell Biology, Immunology and Infection, Discipline of Microbiology and Immunology Rosalind Franklin University of Medicine and Science Chicago Illinois USA
| | - Renata M. Pereira
- Instituto de Microbiologia Paulo de Góes, Departamento de Imunologia Universidade Federal do Rio de Janeiro Rio de Janeiro RJ Brazil
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Chiara VD, Daxinger L, Staal FJT. The Route of Early T Cell Development: Crosstalk between Epigenetic and Transcription Factors. Cells 2021; 10:1074. [PMID: 33946533 PMCID: PMC8147249 DOI: 10.3390/cells10051074] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2021] [Revised: 04/25/2021] [Accepted: 04/26/2021] [Indexed: 12/21/2022] Open
Abstract
Hematopoietic multipotent progenitors seed the thymus and then follow consecutive developmental stages until the formation of mature T cells. During this process, phenotypic changes of T cells entail stage-specific transcriptional programs that underlie the dynamic progression towards mature lymphocytes. Lineage-specific transcription factors are key drivers of T cell specification and act in conjunction with epigenetic regulators that have also been elucidated as crucial players in the establishment of regulatory networks necessary for proper T cell development. In this review, we summarize the activity of transcription factors and epigenetic regulators that together orchestrate the intricacies of early T cell development with a focus on regulation of T cell lineage commitment.
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Affiliation(s)
- Veronica Della Chiara
- Department of Human Genetics, Leiden University Medical Centre (LUMC), 2300 RC Leiden, The Netherlands; (V.D.C.); (L.D.)
| | - Lucia Daxinger
- Department of Human Genetics, Leiden University Medical Centre (LUMC), 2300 RC Leiden, The Netherlands; (V.D.C.); (L.D.)
| | - Frank J. T. Staal
- Department of Immunology, Leiden University Medical Center, 2333 ZA Leiden, The Netherlands
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Differentiation and Establishment of Dental Epithelial-Like Stem Cells Derived from Human ESCs and iPSCs. Int J Mol Sci 2020; 21:ijms21124384. [PMID: 32575634 PMCID: PMC7352334 DOI: 10.3390/ijms21124384] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2020] [Accepted: 06/17/2020] [Indexed: 12/13/2022] Open
Abstract
Tooth development and regeneration occur through reciprocal interactions between epithelial and ectodermal mesenchymal stem cells. However, the current studies on tooth development are limited, since epithelial stem cells are relatively difficult to obtain and maintain. Human embryonic stem cells (hESCs) and induced pluripotent stem cells (hiPSCs) may be alternative options for epithelial cell sources. To differentiate hESCs/hiPSCs into dental epithelial-like stem cells, this study investigated the hypothesis that direct interactions between pluripotent stem cells, such as hESCs or hiPSCs, and Hertwig's epithelial root sheath/epithelial rests of Malassez (HERS/ERM) cell line may induce epithelial differentiation. Epithelial-like stem cells derived from hES (EPI-ES) and hiPSC (EPI-iPSC) had morphological and immunophenotypic characteristics of HERS/ERM cells, as well as similar gene expression. To overcome a rare population and insufficient expansion of primary cells, EPI-iPSC was immortalized with the SV40 large T antigen. The immortalized EPI-iPSC cell line had a normal karyotype, and a short tandem repeat (STR) analysis verified that it was derived from hiPSCs. The EPI-iPSC cell line co-cultured with dental pulp stem cells displayed increased amelogenic and odontogenic gene expression, exhibited higher dentin sialoprotein (DSPP) protein expression, and promoted mineralized nodule formation. These results indicated that the direct co-culture of hESCs/hiPSCs with HERS/ERM successfully established dental epithelial-like stem cells. Moreover, this differentiation protocol could help with understanding the functional roles of cell-to-cell communication and tissue engineering of teeth.
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DE BRAEKELEER MARC, TOUS CORINE, GUÉGANIC NADIA, LE BRIS MARIEJOSÉE, BASINKO AUDREY, MOREL FRÉDÉRIC, DOUET-GUILBERT NATHALIE. Immunoglobulin gene translocations in chronic lymphocytic leukemia: A report of 35 patients and review of the literature. Mol Clin Oncol 2016; 4:682-694. [PMID: 27123263 PMCID: PMC4840758 DOI: 10.3892/mco.2016.793] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2015] [Accepted: 02/09/2016] [Indexed: 12/20/2022] Open
Abstract
Chronic lymphocytic leukemia (CLL) represents the most common hematological malignancy in Western countries, with a highly heterogeneous clinical course and prognosis. Translocations involving the immunoglobulin (IG) genes are regularly identified. From 2000 to 2014, we identified an IG gene translocation in 18 of the 396 patients investigated at diagnosis (4.6%) and in 17 of the 275 analyzed during follow-up (6.2%). A total of 4 patients in whom the IG translocation was identified at follow-up did not carry the translocation at diagnosis. The IG heavy locus (IGH) was involved in 27 translocations (77.1%), the IG κ locus (IGK) in 1 (2.9%) and the IG λ locus (IGL) in 7 (20.0%). The chromosome band partners of the IG translocations were 18q21 in 16 cases (45.7%), 11q13 and 19q13 in 4 cases each (11.4% each), 8q24 in 3 cases (8.6%), 7q21 in 2 cases (5.7%), whereas 6 other bands were involved once (2.9% each). At present, 35 partner chromosomal bands have been described, but the partner gene has solely been identified in 10 translocations. CLL associated with IG gene translocations is characterized by atypical cell morphology, including plasmacytoid characteristics, and the propensity of being enriched in prolymphocytes. The IG heavy chain variable region (IGHV) mutational status varies between translocations, those with unmutated IGHV presumably involving cells at an earlier stage of B-cell lineage. All the partner genes thus far identified are involved in the control of cell proliferation and/or apoptosis. The translocated partner gene becomes transcriptionally deregulated as a consequence of its transposition into the IG locus. With the exception of t(14;18)(q32;q21) and its variants, prognosis appears to be poor for the other translocations. Therefore, searching for translocations involving not only IGH, but also IGL and IGK, by banding and molecular cytogenetics is required. Furthermore, it is important to identify the partner gene to ensure the patients receive the optimal treatment.
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Affiliation(s)
- MARC DE BRAEKELEER
- Faculty of Medicine and Health Sciences, University of Brest, Brest, France
- National Institute of Health and Medical Research (INSERM U1078), Brest, France
- Department of Cytogenetics and Reproductive Biology, Morvan Hospital, Regional University Hospital Center of Brest (CHRU), Brest, France
| | - CORINE TOUS
- Department of Cytogenetics and Reproductive Biology, Morvan Hospital, Regional University Hospital Center of Brest (CHRU), Brest, France
| | - NADIA GUÉGANIC
- Faculty of Medicine and Health Sciences, University of Brest, Brest, France
- National Institute of Health and Medical Research (INSERM U1078), Brest, France
| | - MARIE-JOSÉE LE BRIS
- Department of Cytogenetics and Reproductive Biology, Morvan Hospital, Regional University Hospital Center of Brest (CHRU), Brest, France
| | - AUDREY BASINKO
- National Institute of Health and Medical Research (INSERM U1078), Brest, France
- Department of Cytogenetics and Reproductive Biology, Morvan Hospital, Regional University Hospital Center of Brest (CHRU), Brest, France
| | - FRÉDÉRIC MOREL
- Faculty of Medicine and Health Sciences, University of Brest, Brest, France
- National Institute of Health and Medical Research (INSERM U1078), Brest, France
- Department of Cytogenetics and Reproductive Biology, Morvan Hospital, Regional University Hospital Center of Brest (CHRU), Brest, France
| | - NATHALIE DOUET-GUILBERT
- Faculty of Medicine and Health Sciences, University of Brest, Brest, France
- National Institute of Health and Medical Research (INSERM U1078), Brest, France
- Department of Cytogenetics and Reproductive Biology, Morvan Hospital, Regional University Hospital Center of Brest (CHRU), Brest, France
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The roles of Polycomb group proteins in hematopoietic stem cells and hematological malignancies. Int J Hematol 2016; 103:634-42. [PMID: 27086351 DOI: 10.1007/s12185-016-2011-5] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2016] [Revised: 04/07/2016] [Accepted: 04/07/2016] [Indexed: 12/19/2022]
Abstract
Polycomb group (PcG) proteins are epigenetic regulatory factors that maintain the repression of target gene expression through histone modification. PcG proteins control the repression of genes that regulate differentiation and the cell cycle in the maintenance of hematopoietic stem cells (HSC). Moreover, abnormalities in expression level and mutations in PcG genes have been reported in various types of cancer, including hematological malignancies. In this review, we present an overview of the roles of PcG proteins in HSC and various types of hematological malignancies.
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The BMI1 polycomb protein represses cyclin G2-induced autophagy to support proliferation in chronic myeloid leukemia cells. Leukemia 2015; 29:1993-2002. [PMID: 25925206 DOI: 10.1038/leu.2015.112] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2014] [Revised: 03/27/2015] [Accepted: 03/30/2015] [Indexed: 12/16/2022]
Abstract
The BMI1 polycomb protein regulates self-renewal, proliferation and survival of cancer-initiating cells essentially through epigenetic repression of the CDKN2A tumor suppressor locus. We demonstrate here for the first time that BMI1 also prevents autophagy in chronic myeloid leukemia (CML) cell lines, to support their proliferation and clonogenic activity. Using chromatin immunoprecipitation, we identified CCNG2/cyclin G2 (CCNG2) as a direct BMI1 target. BMI1 downregulation in CD34+ CML cells by PTC-209 pharmacological treatment or shBMI1 transduction triggered CCNG2 expression and decreased clonogenic activity. Also, ectopic expression of CCNG2 in CD34+ CML cells strongly decreased their clonogenicity. CCNG2 was shown to act by disrupting the phosphatase 2A complex, which activates a PKCζ-AMPK-JNK-ERK pathway that engages autophagy. We observed that BMI1 and CCNG2 levels evolved inversely during the progression of CML towards an acute deadly phase, and therefore hypothesized that BMI1 could support acute transformation of CML through the silencing of a CCNG2-mediated tumor-suppressive autophagy response.
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Skvarova Kramarzova K, Fiser K, Mejstrikova E, Rejlova K, Zaliova M, Fornerod M, Drabkin HA, van den Heuvel-Eibrink MM, Stary J, Trka J, Starkova J. Homeobox gene expression in acute myeloid leukemia is linked to typical underlying molecular aberrations. J Hematol Oncol 2014; 7:94. [PMID: 25539595 PMCID: PMC4310032 DOI: 10.1186/s13045-014-0094-0] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2014] [Accepted: 12/04/2014] [Indexed: 02/02/2023] Open
Abstract
Background Although distinct patterns of homeobox (HOX) gene expression have been described in defined cytogenetic and molecular subsets of patients with acute myeloid leukemia (AML), it is unknown whether these patterns are the direct result of transcriptional alterations or rather represent the differentiation stage of the leukemic cell. Method To address this question, we used qPCR to analyze mRNA expression of HOXA and HOXB genes in bone marrow (BM) samples of 46 patients with AML and sorted subpopulations of healthy BM cells. These various stages of myeloid differentiation represent matched counterparts of morphological subgroups of AML. To further study the transcriptional alterations of HOX genes in hematopoiesis, we also analyzed gene expression of epigenetic modifiers in the subpopluations of healthy BM and leukemic cells. Results Unsupervised hierarchical clustering divided the AMLs into five clusters characterized by the presence of prevalent molecular genetic aberrations. Notably, the impact of genotype on HOX gene expression was significantly more pronounced than that of the differentiation stage of the blasts. This driving role of molecular aberrations was best exemplified by the repressive effect of the PML-RARa fusion gene on HOX gene expression, regardless of the presence of the FLT3/ITD mutation. Furthermore, HOX gene expression was positively correlated with mRNA levels of histone demethylases (JMJD3 and UTX) and negatively correlated with gene expression of DNA methyltranferases. No such relationships were observed in subpopulations of healthy BM cells. Conclusion Our results demonstrate that specific molecular genetic aberrations, rather than differentiation per se, underlie the observed differences in HOX gene expression in AML. Moreover, the observed correlations between epigenetic modifiers and HOX ex pression that are specific to malignant hematopoiesis, suggest their potential causal relationships. Electronic supplementary material The online version of this article (doi:10.1186/s13045-014-0094-0) contains supplementary material, which is available to authorized users.
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Salonen J, Rönnholm G, Kalkkinen N, Vihinen M. Proteomic changes during B cell maturation: 2D-DIGE approach. PLoS One 2013; 8:e77894. [PMID: 24205016 PMCID: PMC3812168 DOI: 10.1371/journal.pone.0077894] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2013] [Accepted: 09/06/2013] [Indexed: 11/18/2022] Open
Abstract
B cells play a pivotal role in adaptive immune system, since they maintain a delicate balance between recognition and clearance of foreign pathogens and tolerance to self. During maturation, B cells progress through a series of developmental stages defined by specific phenotypic surface markers and the rearrangement and expression of immunoglobulin (Ig) genes. To get insight into B cell proteome during the maturation pathway, we studied differential protein expression in eight human cell lines, which cover four distinctive developmental stages; early pre-B, pre-B, plasma cell and immature B cell upon anti-IgM stimulation. Our two-dimensional differential gel electrophoresis (2D-DIGE) and mass spectrometry based proteomic study indicates the involvement of large number of proteins with various functions. Notably, proteins related to cytoskeleton were relatively highly expressed in early pre-B and pre-B cells, whereas plasma cell proteome contained endoplasmic reticulum and Golgi system proteins. Our long time series analysis in anti-IgM stimulated Ramos B cells revealed the dynamic regulation of cytoskeleton organization, gene expression and metabolic pathways, among others. The findings are related to cellular processes in B cells and are discussed in relation to experimental information for the proteins and pathways they are involved in. Representative 2D-DIGE maps of different B cell maturation stages are available online at http://structure.bmc.lu.se/BcellProteome/.
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Affiliation(s)
- Johanna Salonen
- Institute of Biomedical Technology, University of Tampere, Tampere, Finland
- BioMediTech, Tampere, Finland
- Research Unit, Tampere University Hospital, Tampere, Finland
| | - Gunilla Rönnholm
- Institute of Biotechnology, University of Helsinki, Helsinki, Finland
| | - Nisse Kalkkinen
- Institute of Biotechnology, University of Helsinki, Helsinki, Finland
| | - Mauno Vihinen
- Institute of Biomedical Technology, University of Tampere, Tampere, Finland
- BioMediTech, Tampere, Finland
- Research Unit, Tampere University Hospital, Tampere, Finland
- Department of Experimental Medical Science, Lund University, Lund, Sweden
- * E-mail:
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Rouhigharabaei L, Ferreiro JF, Put N, Michaux L, Tousseyn T, Lefebvre C, Gardiner A, De Kelver W, Demuynck H, Verschuere J, Théate I, Vicente C, Vandenberghe P, Cools J, Wlodarska I. BMI1, the polycomb-group gene, is recurrently targeted by genomic rearrangements in progressive B-cell leukemia/lymphoma. Genes Chromosomes Cancer 2013; 52:928-44. [PMID: 23873701 DOI: 10.1002/gcc.22088] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2013] [Accepted: 06/13/2013] [Indexed: 01/10/2023] Open
Abstract
BMI1, a Polycomb-group gene located at 10p12.2, is implicated in the pathogenesis of a variety of tumors. However, the genetic molecular mechanisms underlying its aberrant expression in cancer cells remain largely unknown. In this study, we show that BMI1 is recurrently targeted by chromosomal aberrations in B-cell leukemia/lymphoma. We identified a novel t(10;14)(p12;q32)/IGH-BMI1 rearrangement and its IGL variant in six cases of chronic lymphocytic leukemia (CLL) and found that these aberrations were consistently acquired at time of disease progression and high grade transformation of leukemia (Richter syndrome). The IG-BMI1 translocations were not associated with any particular molecular subtype of CLL and the leukemias were negative for common mutations of NOTCH1 and TP53, known to increase a risk of progression and transformation in CLL. In addition, using FISH and SNP array analysis, we identified a wide range of BMI1-involving 10p12 lesions in 17 cases of mantle cell lymphoma (MCL). These aberrations included various balanced and unbalanced structural abnormalities and very frequently but not exclusively, were associated with gain of the BMI1 locus and loss of the 10p terminal sequences. These findings point to genomic instability at the 10p region in MCL which likely promotes rearrangements and deregulation of BMI1. Our findings are in line with previously published observations correlating overexpression of BMI1 with tumor progression and chemoresistance. In summary, our study provides new insights into genetic molecular mechanisms underlying aberrant expression of BMI1 in lymphoma and documents its contribution in the pathogenesis of Richter syndrome and MCL.
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Qi L, Cao JL, Hu Y, Yang JG, Ji Y, Huang J, Zhang Y, Sun DG, Xia HF, Ma X. The dynamics of polycomb group proteins in early embryonic nervous system in mouse and human. Int J Dev Neurosci 2013; 31:487-95. [PMID: 23727134 DOI: 10.1016/j.ijdevneu.2013.05.005] [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: 05/09/2013] [Accepted: 05/12/2013] [Indexed: 10/26/2022] Open
Abstract
Polycomb group (PcG) proteins are transcription regulatory proteins that control the expression of a variety of genes and the antero-posterior neural patterning from early embryogenesis. Although expression of PcG genes in the nervous system has been noticed, but the expression pattern of PcG proteins in early embryonic nervous system is still unclear. In this study, we analyzed the expression pattern of PRC1 complex members (BMI-1 and RING1B) and PRC2 complex members (EED, SUZ12 and EZH2) in early embryonic nervous system in mouse and human by Western blot and Immunohistochemistry. The results of Western blot showed that EED protein was significantly up-regulated with the increase of the day of pregnancy during the early embryogenesis in mouse. BMI-1 protein level was significantly increased from the day 10 of pregnancy, when compared with the day 9 of pregnancy. But the SUZ12, EZH2 and RING1B protein level did not change significantly. From the results of Immunohistochemistry, we found that the four PcG proteins were all expressed in the fetal brain and fetal spinal cord in mouse. In human, the expression of EED, SUZ12, and EZH2 was not significantly different in cerebral cortex and sacral spinal cord, but BMI-1 and RING1B expression was enhanced with the development of embryos in early pregnancy. Collectively, our findings showed that PRC1 and PRC2 were spatiotemporally expressed in brain and spinal cord of early embryos.
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Affiliation(s)
- Lu Qi
- Chongqing Key Laboratory of Birth Defects and Reproductive Health, Chongqing, China; Graduate Schools, Peking Union Medical College, Beijing, China; Reproductive and Genetic Center of National Research Institute for Family Planning, Beijing, China
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Polycomb-group proteins in hematopoietic stem cell regulation and hematopoietic neoplasms. Leukemia 2012; 27:523-33. [PMID: 23257781 DOI: 10.1038/leu.2012.368] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
The equilibrium between self-renewal and differentiation of hematopoietic stem cells is regulated by epigenetic mechanisms. In particular, Polycomb-group (PcG) proteins have been shown to be involved in this process by repressing genes involved in cell-cycle regulation and differentiation. PcGs are histone modifiers that reside in two multi-protein complexes: Polycomb Repressive Complex 1 and 2 (PRC1 and PRC2). The existence of multiple orthologs for each Polycomb gene allows the formation of a multitude of distinct PRC1 and PRC2 sub-complexes. Changes in the expression of individual PcG genes are likely to cause perturbations in the composition of the PRC, which affect PRC enzymatic activity and target selectivity. An interesting recent development is that aberrant expression of, and mutations in, PcG genes have been shown to occur in hematopoietic neoplasms, where they display both tumor-suppressor and oncogenic activities. We therefore comprehensively reviewed the latest research on the role of PcG genes in normal and malignant blood cell development. We conclude that future research to elucidate the compositional changes of the PRCs and methods to intervene in PRC assembly will be of great therapeutic relevance to combat hematological malignancies.
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Lee JH, Khor TO, Shu L, Su ZY, Fuentes F, Kong ANT. Dietary phytochemicals and cancer prevention: Nrf2 signaling, epigenetics, and cell death mechanisms in blocking cancer initiation and progression. Pharmacol Ther 2012; 137:153-71. [PMID: 23041058 DOI: 10.1016/j.pharmthera.2012.09.008] [Citation(s) in RCA: 160] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2012] [Accepted: 09/17/2012] [Indexed: 02/06/2023]
Abstract
Reactive metabolites from carcinogens and oxidative stress can drive genetic mutations, genomic instability, neoplastic transformation, and ultimately carcinogenesis. Numerous dietary phytochemicals in vegetables/fruits have been shown to possess cancer chemopreventive effects in both preclinical animal models and human epidemiological studies. These phytochemicals could prevent the initiation of carcinogenesis via either direct scavenging of reactive oxygen species/reactive nitrogen species (ROS/RNS) or, more importantly, the induction of cellular defense detoxifying/antioxidant enzymes. These defense enzymes mediated by Nrf2-antioxidative stress and anti-inflammatory signaling pathways can contribute to cellular protection against ROS/RNS and reactive metabolites of carcinogens. In addition, these compounds would kill initiated/transformed cancer cells in vitro and in in vivo xenografts via diverse anti-cancer mechanisms. These mechanisms include the activation of signaling kinases (e.g., JNK), caspases and the mitochondria damage/cytochrome c pathways. Phytochemicals may also have anti-cancer effects by inhibiting the IKK/NF-κB pathway, inhibiting STAT3, and causing cell cycle arrest. In addition, other mechanisms may include epigenetic alterations (e.g., inhibition of HDACs, miRNAs, and the modification of the CpG methylation of cancer-related genes). In this review, we will discuss: the current advances in the study of Nrf2 signaling; Nrf2-deficient tumor mouse models; the epigenetic control of Nrf2 in tumorigenesis and chemoprevention; Nrf2-mediated cancer chemoprevention by naturally occurring dietary phytochemicals; and the mutation or hyper-expression of the Nrf2-Keap1 signaling pathway in advanced tumor cells. The future development of dietary phytochemicals for chemoprevention must integrate in vitro signaling mechanisms, relevant biomarkers of human diseases, and combinations of different phytochemicals and/or non-toxic therapeutic drugs, including NSAIDs.
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Affiliation(s)
- Jong Hun Lee
- Center for Cancer Prevention Research, Department of Pharmaceutics, Ernest-Mario School of Pharmacy, Rutgers, the State University of New Jersey, 160 Frelinghuysen Road, Piscataway, NJ 08854, USA
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Characterization of a new ARID family transcription factor (Brightlike/ARID3C) that co-activates Bright/ARID3A-mediated immunoglobulin gene transcription. Mol Immunol 2011; 49:260-72. [PMID: 21955986 DOI: 10.1016/j.molimm.2011.08.025] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2011] [Accepted: 08/27/2011] [Indexed: 11/21/2022]
Abstract
Two members, Bright/ARID3A and Bdp/ARID3B, of the ARID (AT-Rich Interaction Domain) transcription family are distinguished by their ability to specifically bind to DNA and to self-associate via a second domain, REKLES. Bright and Bdp positively regulate immunoglobulin heavy chain gene (IgH) transcription by binding to AT-rich motifs within Matrix Associating Regions (MARs) residing within a subset of V(H) promoters and the Eμ intronic enhancer. In addition, REKLES provides Bright nuclear export function, and a small pool of Bright is directed to plasma membrane sub-domains/lipid rafts where it associates with and modulates signaling of the B cell antigen receptor (BCR). Here, we characterize a third, highly conserved, physically condensed ARID3 locus, Brightlike/ARID3C. Brightlike encodes two alternatively spliced, SUMO-I-modified isoforms that include or exclude (Δ6) the REKLES-encoding exon 6. Brightlike transcripts and proteins are expressed preferentially within B lineage lymphocytes and coordinate with highest Bright expression in activated follicular B cells. Brightlike, but not BrightlikeΔ6, undergoes nuclear-cytoplasmic shuttling with a fraction localizing within lipid rafts following BCR stimulation. Brightlike, but not BrightlikeΔ6, associates with Bright in solution, at common DNA binding sites in vitro, and is enriched at Bright binding sites in chromatin. Although possessing little transactivation capacity of its own, Brightlike significantly co-activates Bright-dependent IgH transcription with maximal activity mediated by the unsumoylated form. In sum, this report introduces Brightlike as an additional functional member of the family of ARID proteins, which should be considered in regulatory circuits, previously ascribed to be mediated by Bright.
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Nakahara O, Takamori H, Iwatsuki M, Baba Y, Sakamoto Y, Tanaka H, Chikamoto A, Horino K, Beppu T, Kanemitsu K, Honda Y, Iyama KI, Baba H. Carcinogenesis of intraductal papillary mucinous neoplasm of the pancreas: loss of microRNA-101 promotes overexpression of histone methyltransferase EZH2. Ann Surg Oncol 2011; 19 Suppl 3:S565-71. [PMID: 21932133 DOI: 10.1245/s10434-011-2068-6] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2011] [Indexed: 12/30/2022]
Abstract
BACKGROUND The mechanisms of IPMN carcinogenesis are as yet unclear. This study aimed to determine whether expression of EZH2 promotes neoplastic progression of IPMN and PDCA, and to elucidate regulation of EZH2 expression by miR-101. METHODS EZH2 mRNA and protein expression were investigated in 8 human pancreatic cancer cell lines by PCR and western blotting. Pre-miR-101 and anti-miR-101 were transfected into pancreatic cancer cells to elucidate EZH2 regulation by miR-101. To evaluate whether EZH2 modulates malignant progression of IPMN, EZH2 expression in IPMN was examined by immunohistochemistry. Next, we collected malignant and benign cells from FFPE samples of IPMNs using laser capture microdissection and extracted the RNA. miR-101 expression in IPMN was assessed using real-time PCR. RESULTS All pancreatic cancer cell lines expressed EZH2 mRNA and protein. The induction of miR-101 by transfection of pre-miR-101 in MIA PaCa-2 was closely related to a reduction in EZH2 protein production compared with control, whereas there was little difference in the expression of EZH2 mRNA. Anti-miR-101 transfected pancreatic cancer cells showed an increase in EZH2 protein, while the level of EZH2 mRNA was not elevated. Immunohistochemistry revealed that the expression of EZH2 was significantly higher in malignant than benign IPMN. Expression of miR-101 was significantly lower in malignant IPMN than benign IPMN. CONCLUSIONS MiR-101 targets EZH2 at the posttranscriptional level, and loss of miR-101 could be a trigger for the adenomacarcinoma sequence of IPMN by upregulation of EZH2. This study suggests miR-101-EZH2 blockade as a potential therapeutic target in IPMN carcinogenesis.
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Affiliation(s)
- Osamu Nakahara
- Department of Gastroenterological Surgery, Graduate School of Medical Sciences, Kumamoto University, Kumamoto, Japan
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Jacob E, Hod-Dvorai R, Ben-Mordechai OL, Boyko Y, Avni O. Dual function of polycomb group proteins in differentiated murine T helper (CD4+) cells. J Mol Signal 2011; 6:5. [PMID: 21624129 PMCID: PMC3127800 DOI: 10.1186/1750-2187-6-5] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2011] [Accepted: 05/30/2011] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Following antigen recognition, naive T helper (Th; CD4+) cells can differentiate toward one of several effector lineages such as Th1 and Th2; each expressing distinctive transcriptional profiles of cytokine genes. These cytokines eventually instruct the strategy of the immune response. In our search for factors that propagate the transcriptional programs of differentiated Th cells, we previously found that Polycomb group (PcG) proteins, which are known as epigenetic regulators that maintain repressive chromatin states, bind differentially the signature cytokine genes. Unexpectedly, their binding to the Ifng (Interferon-g) in Th1 cells and Il4 (Interleukin-4) in Th2 cells, was correlated with transcriptional activation. Therefore, in this study we aimed to determine the functional role of PcG proteins in the regulation of the expression of the signature cytokine genes. METHODS PcG proteins were knocked down in primary and established murine Th cells using transduction of lentiviruses encoding short hairpin RNAs (shRNAs) directed to Mel-18, Ezh2, Eed and Ring1A, representative of two different PcG complexes. The chromatin structure and the binding activity of PcG proteins and transcription factors at the Ifng promoter were assessed by chromatin immunoprecipitation (ChIP) assays. RESULTS Downregulation of PcG proteins was consistent with their function as positive regulators of the signature cytokine genes in primary and established Th1 and Th2 cells. Moreover, the PcG protein Mel-18 was necessary to recruit the Th1-lineage specifying transcription factor T-bet, and the T cell receptor (TCR)-inducible transcription factor NFAT1 to the Ifng promoter in Th1 cells. Nevertheless, our results suggest that PcG proteins can function also as conventional transcriptional repressors in Th cells of their known target the Hoxa7 gene. CONCLUSIONS Our data support a model whereby the non-differentially expressed PcG proteins are recruited in a Th-lineage specific manner to their target genes to enforce the maintenance of specific transcriptional programs as transcriptional repressors or activators. Although our results suggest a direct effect of PcG proteins in the regulation of cytokine gene expression, indirect functions cannot be excluded.
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Affiliation(s)
- Eyal Jacob
- Department of Immunology, Rappaport Faculty of Medicine, Technion-Israel Institute of Technology, Haifa 31096, Israel.
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16
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Nam H, Kim J, Park J, Park JC, Kim JW, Seo BM, Lee JC, Lee G. Expression profile of the stem cell markers in human Hertwig's epithelial root sheath/Epithelial rests of Malassez cells. Mol Cells 2011; 31:355-60. [PMID: 21359676 PMCID: PMC3933961 DOI: 10.1007/s10059-011-0045-3] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2010] [Revised: 01/14/2011] [Accepted: 01/14/2011] [Indexed: 12/12/2022] Open
Abstract
Hertwig's epithelial root sheath/Epithelial rests of Malassez (HERS/ERM) cells are unique epithelial cells in the periodontal ligament. They remain in periodontal tissues through-out the adult life, and it is expected that their functional role is to maintain the homeostasis of the periodontium through reciprocal interactions with other periodontal cells. In this study, we investigated whether HERS/ERM cells have primitive stem cell characteristics: those of embryonic stem cells as well as of epithelial stem cells. Primary HERS/ERM cells had typical epithelial cell morphology and characteristics and they maintained for more than five passages. They expressed epithelial stem cell-related genes: ABCG2, ANp63, p75, EpCAM, and Bmi-1. Moreover, the expression of embryonic stem cell markers such as Oct-4, Nanog, and SSEA-4 were detected. Next, we investigated whether the expression of these stem cell markers was maintained during the sub-culture process. HERS/ERM cells showed different expression levels of these stemness genes at each passage, but their expression was maintained throughout the passages. Taken together, our data suggest that a primary culture of HERS/ERM cells contains a population of primitive stem cells that express epithelial stem cell markers and embryonic stem cell markers. Furthermore, these cell populations were maintained during the sub-culturing process in our culture conditions. Therefore, our findings suggest that there is a strong possibility of accomplishing cementum tissue engineering with HERS/ERM cells.
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Affiliation(s)
| | | | | | - Joo-Cheol Park
- Department of Oral Histology-Developmental Biology, School of Dentistry, Seoul National University, Seoul 110-749, Korea
| | - Jung-Wook Kim
- Department of Pediatric Dentistry, School of Dentistry, Seoul National University, Seoul 110-749, Korea
| | - Byoung-Moo Seo
- Department of Oral and Maxillofacial Surgery, School of Dentistry, Seoul National University, Seoul 110-749, Korea
| | - Jae Cheoun Lee
- Children’s Dental Center and CDC Baby Tooth Stem Cell Bank, Seoul 135-953, Korea
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17
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Konuma T, Oguro H, Iwama A. Role of the polycomb group proteins in hematopoietic stem cells. Dev Growth Differ 2010; 52:505-16. [DOI: 10.1111/j.1440-169x.2010.01191.x] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
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18
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Oguro H, Yuan J, Ichikawa H, Ikawa T, Yamazaki S, Kawamoto H, Nakauchi H, Iwama A. Poised lineage specification in multipotential hematopoietic stem and progenitor cells by the polycomb protein Bmi1. Cell Stem Cell 2010; 6:279-86. [PMID: 20207230 DOI: 10.1016/j.stem.2010.01.005] [Citation(s) in RCA: 167] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2009] [Revised: 11/25/2009] [Accepted: 01/08/2010] [Indexed: 10/19/2022]
Abstract
Polycomb group (PcG) proteins are essential regulators of stem cells. PcG and trithorax group proteins mark developmental regulator gene promoters with bivalent domains consisting of overlapping repressive and activating histone modifications to keep them poised for activation in embryonic stem cells. Bmi1, a component of PcG complexes, maintains the self-renewal capacity of adult stem cells, but its role in multipotency remains obscure. Here we show that Bmi1 is critical for multipotency of hematopoietic stem cells (HSCs) and multipotent progenitors (MPPs). B cell lineage developmental regulator genes, Ebf1 and Pax5, appeared to be transcriptionally repressed by bivalent domains before lineage commitment. Loss of Bmi1 resulted in a resolution of bivalent domains at the Ebf1 and Pax5 loci, leading to their premature expression in HSC/MPPs accompanied by accelerated lymphoid specification and a marked reduction in HSC/MPPs. Thus, Bmi1 is required to reinforce bivalent domains at key developmental regulator gene loci to maintain lineage specification poised for activation in adult stem cells.
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Affiliation(s)
- Hideyuki Oguro
- Department of Cellular and Molecular Medicine, Graduate School of Medicine, Chiba University, Chiba 260-8670, Japan
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19
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Sasaki M, Yamaguchi J, Ikeda H, Itatsu K, Nakanuma Y. Polycomb group protein Bmi1 is overexpressed and essential in anchorage-independent colony formation, cell proliferation and repression of cellular senescence in cholangiocarcinoma: tissue and culture studies. Hum Pathol 2009; 40:1723-30. [PMID: 19695678 DOI: 10.1016/j.humpath.2009.01.027] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/24/2008] [Revised: 01/10/2009] [Accepted: 01/16/2009] [Indexed: 11/18/2022]
Abstract
Polycomb-group proteins Bmi1 is regarded as a "stemness" gene involved in the maintenance of stem cells, malignant transformation, and biologic aggressiveness of several human carcinomas. We examined the significance of the Bmi1 expression in intrahepatic cholangiocarcinoma. The expression of Bmi1 was examined in intrahepatic cholangiocarcinoma (n = 30; 9 bile ductular carcinoma, 8 intrahepatic cholangiocarcinoma of peripheral type, and 13 of hilar type) by using immunohistochemistry and real-time polymerase chain reaction. The expression level of Bmi1 was assessed in 7 cholangiocarcinoma cell lines. The effect of Bmi1 knockdown was examined in cultured cholangiocarcinoma cells (HuCCT1 and TFK-1) using small interfering RNA. Bmi1 was consistently expressed in nonneoplastic biliary epithelial cells and in all intrahepatic cholangiocarcinoma, irrespective of the location and histological degree of differentiation. The level of mRNA expression was significantly higher in 13 (81.3%) of 16 intrahepatic cholangiocarcinoma compared with the corresponding nonneoplastic tissues. All 7 cultured cholangiocarcinoma cells overexpressed Bmi1 to various degrees. The knockdown of Bmi1 resulted in decreased colony formation, decreased cell proliferation activities, and increased cellular senescence. The overexpression of polycomb-group protein Bmi1 is essential for colony formation and cell proliferation, probably by the repression of cellular senescence in intrahepatic cholangiocarcinoma.
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Affiliation(s)
- Motoko Sasaki
- Department of Human Pathology, Kanazawa University Graduate School of Medicine, Kanazawa, Japan
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20
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Abstract
The Polycomb group (PcG) proteins are transcriptional repressors that regulate lineage choices during development and differentiation. Recent studies have advanced our understanding of how the PcG proteins regulate cell fate decisions and how their deregulation potentially contributes to cancer. In this Review we discuss the emerging roles of long non-coding RNAs (ncRNAs) and a subset of transcription factors, which we call cell fate transcription factors, in the regulation of PcG association with target genes. We also speculate about how their deregulation contributes to tumorigenesis.
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Affiliation(s)
- Adrian P Bracken
- The Smurfit Institute of Genetics, Trinity College Dublin and The Adelaide & Meath Hospital, including the National Children's Hospital, Dublin, Ireland.
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21
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Nam H, Lee G. Identification of novel epithelial stem cell-like cells in human deciduous dental pulp. Biochem Biophys Res Commun 2009; 386:135-9. [PMID: 19501569 DOI: 10.1016/j.bbrc.2009.05.141] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2009] [Accepted: 05/30/2009] [Indexed: 01/09/2023]
Abstract
It is well known that interactions between epithelial components and mesenchymal components are essential for tooth development. Therefore, it has been postulated that both types of stem cells might be involved in the regeneration of dental hard tissues. Recently, mesenchymal dental pulp stem cells that have odontogenic potential were identified from human dental pulp. However, the existence of epithelial cells has never been reported in human dental pulp. In the present study, we isolated and characterized epithelial cell-like cells from human deciduous dental pulp. They had characteristic epithelial morphology and expressed epithelial markers. Moreover, they expressed epithelial stem cell-related genes such as ABCG2, Bmi-1, DeltaNp63, and p75. Taken together, our findings suggest that epithelial stem cell-like cells might exist in human deciduous dental pulp and might play a role as an epithelial component for the repair or regeneration of teeth.
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Affiliation(s)
- Hyun Nam
- Laboratory of Molecular Genetics and Stem Cell Differentiation, Dental Research Institute, School of Dentistry, Seoul National University, Seoul 110-749, Republic of Korea
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22
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The overexpression of polycomb group proteins Bmi1 and EZH2 is associated with the progression and aggressive biological behavior of hepatocellular carcinoma. J Transl Med 2008; 88:873-82. [PMID: 18591938 DOI: 10.1038/labinvest.2008.52] [Citation(s) in RCA: 109] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Polycomb-group proteins Bmi1 and EZH2 are involved in the malignant transformation and biological aggressiveness of several human carcinomas. We herein examined the significance of the Bmi1 and EZH2 expression in hepatocellular carcinoma (HCC) and its preneoplastic lesions, dysplastic nodules. The expression of Bmi1 and EZH2 were examined immunohistochemically in HCC (n=27) and dysplastic nodules (n=14), and combined hepatocellular and cholangiocarcinoma (HC-CC) (n=14). The effect of Bmi1 and EZH2 knockdown was examined in cultured HCC cells (HuH7 and HepG2) using siRNA. It was determined that Bmi1 was constantly expressed in cholangiocytes, but not in hepatocytes, and EZH2 was detected in neither cholangiocytes nor hepatocytes. Bmi1 and EZH2 were overexpressed in HCC and more extensively in HC-CC (P<0.01). Interestingly, Bmi1 and EZH2 were not overexpressed in the dysplastic nodules. The expression of Bmi1 and EZH2 was heterogeneous and associated with vascular infiltration, the histological grades, and the cell proliferation activity in HCC and HC-CC. In cultured carcinoma cells overexpressing Bmi1 and EZH2, knockdown of Bmi1 and EZH2 resulted in decreased cell proliferation activities. Therefore, the overexpression of polycomb-group proteins Bmi1 and EZH2 is associated with the malignant progression of HCC, thereby reflecting the aggressive biological behavior in HCC and HC-CC.
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23
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Jacob E, Hod-Dvorai R, Schif-Zuck S, Avni O. Unconventional association of the polycomb group proteins with cytokine genes in differentiated T helper cells. J Biol Chem 2008; 283:13471-81. [PMID: 18285333 DOI: 10.1074/jbc.m709886200] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
The cytokine transcription profiles of developing T helper 1 and T helper 2 cells are imprinted and induced appropriately following stimulation of differentiated cells. Epigenetic regulation combines several mechanisms to ensure the inheritance of transcriptional programs. We found that the expression of the polycomb group proteins, whose role in maintaining gene silencing is well documented, was induced during development in both T helper lineages. Nevertheless, the polycomb proteins, YY1, Mel-18, Ring1A, Ezh2, and Eed, bound to the Il4 and Ifng loci in a differential pattern. In contrast to the prevailing dogma, the binding activity of the polycomb proteins in differentiated T helper cells was associated with cytokine transcription. The polycomb proteins bound to the cytokine genes under resting conditions, and their binding was induced dynamically following stimulation. The recruitment of the polycomb proteins Mel-18 and Ezh2 to the cytokine promoters was inhibited in the presence of cyclosporine A, suggesting the involvement of NFAT. Considering their binding pattern at the cytokine genes and their known function in higher order folding of regulatory elements, we propose a model whereby the polycomb proteins, in some contexts, positively regulate gene expression by mediating long-distance chromosomal interactions.
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Affiliation(s)
- Eyal Jacob
- Department of Immunology, Rappaport Faculty of Medicine, Technion-Israel Institute of Technology, Haifa 31096, Israel
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24
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Inactivation of the polycomb group protein Ring1B unveils an antiproliferative role in hematopoietic cell expansion and cooperation with tumorigenesis associated with Ink4a deletion. Mol Cell Biol 2007; 28:1018-28. [PMID: 18039844 DOI: 10.1128/mcb.01136-07] [Citation(s) in RCA: 73] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Polycomb group (PcG) proteins act as positive regulators of cell proliferation. Ring1B is a PcG gene essential for embryonic development, but its contribution to cell turnover in regenerating tissues in not known. Here, we have generated a conditional mouse mutant line to study the Ring1B role in adult hematopoiesis. Mutant mice developed a hypocellular bone marrow that paradoxically contained an enlarged, hyperproliferating compartment of immature cells, with an intact differentiation potential. These alterations were associated with differential upregulation of cyclin D2, which occurred in all mutant bone marrow cells, and of p16(Ink4a), observed only in the differentiated compartment. Concurrent inactivation of Ink4a rescued the defective proliferation of maturing cells but did not affect the hyperproliferative activity of progenitors and resulted in a shortening of the onset of lymphomas induced by Ink4a inactivation. These data show that Ring1B restricts the progenitors' proliferation and promotes the proliferation of their maturing progeny by selectively altering the expression pattern of cell cycle regulators along hematopoietic differentiation. The novel antiproliferative role of Ring1B's downregulation of a cell cycle activator may play an important role in the tight control of hematopoietic cell turnover.
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25
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Chen Y, Lin MCM, Wang H, Chan CY, Jiang L, Ngai SM, Yu J, He ML, Shaw PC, Yew DT, Sung JJ, Kung HF. Proteomic analysis of EZH2 downstream target proteins in hepatocellular carcinoma. Proteomics 2007; 7:3097-104. [PMID: 17676662 DOI: 10.1002/pmic.200700019] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Enhancer of zeste homolog 2 (EZH2) is suggested to be a potential therapeutic target and a diagnostic marker for cancer. Our previous study also showed the critical role of EZH2 in hepatocellular carcinoma (HCC) tumorigenesis. The present study is aimed at revealing the comprehensive downstream pathways of EZH2 by functional proteomic profiling. Lentivirus mediated RNA interference (RNAi) was employed to knockdown EZH2 in HCC cells. The 2-DE was employed to compare the expression profile difference between parental and EZH2-knockdown HCC cells. In total, 28 spots were differentially expressed during EZH2 inhibition. Among all, 18 proteins were identified by PMF with MALDI-TOF MS. Western blotting further validated upregulation of 60S acidic ribosomal protein P0 (L10E), and downregulation of two proteins with EZH2 inhibition: stathmin1 and probable protein disulfide isomerase (PDI) ER-60 precursor (ERp57). Moreover, L10E was downregulated with overexpression of EZH2 in hepatocytes, and L10E reversed the effect of EZH2 on cell proliferation, suggesting it a downstream target of EZH2. The comprehensive and comparative analyses of proteins associated with EZH2 could further our understanding on the downstream signal cascade of EZH2 leading to tumorigenesis.
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Affiliation(s)
- Yangchao Chen
- Department of Medicine and Therapeutics, The Chinese University of Hong Kong, Shatin, Hong Kong
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26
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van Leenders GJLH, Dukers D, Hessels D, van den Kieboom SWM, Hulsbergen CA, Witjes JA, Otte AP, Meijer CJ, Raaphorst FM. Polycomb-Group Oncogenes EZH2, BMI1, and RING1 Are Overexpressed in Prostate Cancer With Adverse Pathologic and Clinical Features. Eur Urol 2007; 52:455-63. [PMID: 17134822 DOI: 10.1016/j.eururo.2006.11.020] [Citation(s) in RCA: 138] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2006] [Accepted: 11/09/2006] [Indexed: 10/23/2022]
Abstract
OBJECTIVES Polycomb group (PcG) proteins are involved in maintenance of cell identity and proliferation. The protein EZH2 is overexpressed in disseminated prostate cancer, implicating a role of PcG complexes in tumor progression. In this study, we evaluated the expression of eight members of both PcG complexes in clinicopathologically defined prostate cancer. METHODS Components of both PcG protein complexes PRC2 (EZH2, EED, YY1) and PRC1 (BMI1, RING1, HPH1, HPC1, HPC2) were immunohistochemically identified in tissue microarrays of 114 prostate cancer patients. Protein expression was semi-quantitatively scored and correlated with pathologic parameters and recurrence of prostate-specific antigen (PSA). RESULTS Whereas BMI1, RING1, HPC1 and HPH1 were all abundantly present in normal and malignant prostate epithelium, expression of EZH2 occurred in only <10% of cells. Expression of EZH2, BMI1 and RING1 were all significantly enhanced in tumours with Gleason score (GS) > or = 8, extraprostatic extension, positive surgical margins, and PSA recurrence. When only the subgroup of GS < or = 6 was considered, representing the tumour grade in the majority of needle biopsies, EZH2 and BMI1 were also predictive for PSA recurrence. In a multivariable analysis, BMI1 was the only PcG protein with an independent prognostic value. CONCLUSIONS PcG proteins EZH2, BMI1, and RING1 are associated with adverse pathologic features and clinical PSA recurrence of prostate cancer. Whereas BMI1 and RING1 are abundantly present in prostate cancer, EZH2 is expressed at relatively low levels, making it a less obvious target for therapy.
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27
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Gosling KM, Makaroff LE, Theodoratos A, Kim YH, Whittle B, Rui L, Wu H, Hong NA, Kennedy GC, Fritz JA, Yates AL, Goodnow CC, Fahrer AM. A mutation in a chromosome condensin II subunit, kleisin beta, specifically disrupts T cell development. Proc Natl Acad Sci U S A 2007; 104:12445-50. [PMID: 17640884 PMCID: PMC1941488 DOI: 10.1073/pnas.0704870104] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Condensins are ubiquitously expressed multiprotein complexes that are important for chromosome condensation and epigenetic regulation of gene transcription, but whose specific roles in vertebrates are poorly understood. We describe a mouse strain, nessy, isolated during an ethylnitrosourea screen for recessive immunological mutations. The nessy mouse has a defect in T lymphocyte development that decreases circulating T cell numbers, increases their expression of the activation/memory marker CD44, and dramatically decreases the numbers of CD4(+)CD8(+) thymocytes and their immediate DN4 precursors. A missense mutation in an unusual alternatively spliced first exon of the kleisin beta gene, a member of the condensin II complex, was shown to be responsible and act in a T cell-autonomous manner. Despite the ubiquitous expression and role of condensins, kleisin beta(nes/nes) mice were viable, fertile, and showed no defects even in the parallel pathway of B cell lymphocyte differentiation. These data define a unique lineage-specific requirement for kleisin beta in mammalian T cell differentiation.
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Affiliation(s)
| | | | | | | | - Belinda Whittle
- John Curtin School of Medical Research, and
- Australian Phenomics Facility, Australian National University, Canberra ACT 0200 Australia
| | - Lixin Rui
- John Curtin School of Medical Research, and
| | - Hua Wu
- Phenomix Corporation, San Diego, CA 92121; and
| | | | - Gavin C. Kennedy
- Plant Industries, Commonwealth Scientific and Industrial Research Organisation, Canberra ACT 2601 Australia
| | | | | | - Christopher C. Goodnow
- John Curtin School of Medical Research, and
- Australian Phenomics Facility, Australian National University, Canberra ACT 0200 Australia
| | - Aude M. Fahrer
- *School of Biochemistry and Molecular Biology
- To whom correspondence should be addressed. E-mail:
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28
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Kato Y, Koseki H, Vidal M, Nakauchi H, Iwama A. Unique composition of polycomb repressive complex 1 in hematopoietic stem cells. Int J Hematol 2007; 85:179-81. [PMID: 17322001 DOI: 10.1532/ijh97.06235] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
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van Galen JC, Muris JJF, Oudejans JJ, Vos W, Giroth CPE, Ossenkoppele GJ, Otte AP, Raaphorst FM, Meijer CJLM. Expression of the polycomb-group gene BMI1 is related to an unfavourable prognosis in primary nodal DLBCL. J Clin Pathol 2006; 60:167-72. [PMID: 16837630 PMCID: PMC1860630 DOI: 10.1136/jcp.2006.038752] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
BACKGROUND Clinical outcome in patients with diffuse large B cell lymphomas (DLBCL) is highly variable and poorly predictable. Microarray studies showed that patients with DLBCL with a germinal centre B cell-like (GCB) phenotype have a better prognosis than those with an activated B cell-like (ABC) phenotype. The BMI1 proto-oncogene was identified as one of the genes present in the signature of the ABC type of DLBCL, associated with a poor prognosis. OBJECTIVES (1) To investigate, in primary nodal DLBCL, the expression of BMI1 and its association with clinical outcome and DLBCL signature; (2) to look for an association between BMI1 expression and the expression of its putative downstream targets p14ARF and p16INK4a. RESULTS BMI1 expression was found to be associated with poor clinical outcome, but not clearly with an ABC-like phenotype of DLBCL. Expression of BMI1 was frequently, but not always, related to low levels of expression of p14ARF and p16INK4a. CONCLUSION Expression of BMI1 is associated with an unfavourable clinical outcome of primary nodal DLBCL.
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Affiliation(s)
- Joost C van Galen
- Department of Pathology, VU Medical Center, Amsterdam, The Netherlands
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30
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Abstract
Helper T cells coordinate immune responses through the production of cytokines. Th2 cells express the closely linked Il4, Il13, and Il5 cytokine genes, whereas these same genes are silenced in the Th1 lineage. The Th1/Th2 lineage choice has become a textbook example for the regulation of cell differentiation, and recent discoveries have further refined and expanded our understanding of how Th2 differentiation is initiated and reinforced by signals from antigen-presenting cells and cytokine-driven feedback loops. Epigenetic changes that stabilize the active or silent state of the Il4 locus in differentiating helper T cells have been a major focus of recent research. Overall, the field is progressing toward an integrated model of the signaling and transcription factor networks, cis-regulatory elements, epigenetic modifications, and RNA interference mechanisms that converge to determine the lineage fate and gene expression patterns of differentiating helper T cells.
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Affiliation(s)
- K Mark Ansel
- Harvard Medical School, CBR Institute for Biomedical Research, Boston, Massachusetts 02115, USA.
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31
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Muris JJF, Meijer CJLM, Ossenkoppele GJ, Vos W, Oudejans JJ. Apoptosis resistance and response to chemotherapy in primary nodal diffuse large B-cell lymphoma. Hematol Oncol 2006; 24:97-104. [PMID: 16715473 DOI: 10.1002/hon.774] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Diffuse large B-cell lymphomas (DLBCL) represent the most common type of adult malignant lymphoma in western countries and are treated with high dose combination chemotherapy. Although initially the majority of patients respond to this therapy, many do not achieve complete remission and others experience an early relapse. Several studies have shown that prediction of the clinical response to chemotherapy is possible before the start of chemotherapy treatment. Apparently, DLBCL are intrinsically either resistant or sensitive to chemotherapy-induced cell death. Differences in functional integrity of the apoptosis cascade are an important factor predicting outcome in DLBCL. In this review we discuss the possible mechanisms leading to intrinsic resistance to apoptosis and provide an explanation why strong differences in apoptosis sensitivity between DLBCL are observed. Subsequently we will focus on how differences in this intrinsic apoptosis resistance provide an explanation for the variable response to combination chemotherapy and how this can be used for further therapy tailoring.
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32
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Arisan S, Buyuktuncer ED, Palavan-Unsal N, Caşkurlu T, Cakir OO, Ergenekon E. Increased expression of EZH2, a polycomb group protein, in bladder carcinoma. Urol Int 2005; 75:252-7. [PMID: 16215315 DOI: 10.1159/000087804] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2004] [Accepted: 06/13/2005] [Indexed: 01/24/2023]
Abstract
INTRODUCTION Recent experiments have demonstrated that polycomb group gene enhancer zeste homolog 2 (EZH2) is highly expressed in many cancer types. Therefore, we aim to demonstrate EZH2 gene expression in transitional cell bladder cancer. PATIENTS AND METHODS The reverse transcriptase-polymerase chain reaction (RT-PCR) was used for detection of EZH2 mRNA levels in healthy and cancerous human bladder specimens. Also, expression of the particular protein was determined by Western blotting and immunohistochemistry to confirm RT-PCR results. RESULTS Gradually increased expression of EZH2 was detected by mRNA and protein levels in highly advanced bladder cancer specimens. In contrast, 100% of control subjects were negative for EZH2 expression. The expression of EZH2 was more frequent in G3 (92%) than G1-G2 (62-63%) and more frequent in T1-2 (72-85%) than Ta (56%). Western blot analysis results confirm the RT-PCR results. CONCLUSIONS EZH2 overexpression precedes high frequencies of proliferation and the gradual advance of bladder cancer. These observations suggest that deregulated expression of EZH2 is associated with bladder carcinoma.
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MESH Headings
- Aged
- Aged, 80 and over
- Biomarkers, Tumor/biosynthesis
- Biomarkers, Tumor/genetics
- Blotting, Western
- Carcinoma, Transitional Cell/genetics
- Carcinoma, Transitional Cell/metabolism
- Carcinoma, Transitional Cell/pathology
- DNA-Binding Proteins/biosynthesis
- DNA-Binding Proteins/genetics
- Enhancer of Zeste Homolog 2 Protein
- Female
- Follow-Up Studies
- Gene Expression Regulation, Neoplastic/physiology
- Humans
- Immunohistochemistry
- Male
- Middle Aged
- Neoplasm Staging
- Polycomb Repressive Complex 2
- Prospective Studies
- RNA, Messenger/biosynthesis
- RNA, Messenger/genetics
- Reverse Transcriptase Polymerase Chain Reaction
- Transcription Factors/biosynthesis
- Transcription Factors/genetics
- Urinary Bladder Neoplasms/genetics
- Urinary Bladder Neoplasms/metabolism
- Urinary Bladder Neoplasms/pathology
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Affiliation(s)
- Serdar Arisan
- Sisli Etfal Research and Training Hospital, 1st Urology Clinic Sisli, Istanbul, Turkey.
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33
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Cha TL, Zhou BP, Xia W, Wu Y, Yang CC, Chen CT, Ping B, Otte AP, Hung MC. Akt-mediated phosphorylation of EZH2 suppresses methylation of lysine 27 in histone H3. Science 2005; 310:306-10. [PMID: 16224021 DOI: 10.1126/science.1118947] [Citation(s) in RCA: 426] [Impact Index Per Article: 22.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Enhancer of Zeste homolog 2 (EZH2) is a methyltransferase that plays an important role in many biological processes through its ability to trimethylate lysine 27 in histone H3. Here, we show that Akt phosphorylates EZH2 at serine 21 and suppresses its methyltransferase activity by impeding EZH2 binding to histone H3, which results in a decrease of lysine 27 trimethylation and derepression of silenced genes. Our results imply that Akt regulates the methylation activity, through phosphorylation of EZH2, which may contribute to oncogenesis.
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Affiliation(s)
- Tai-Lung Cha
- Department of Molecular and Cellular Oncology, the University of Texas M. D. Anderson Cancer Center, Houston, TX 77030, USA
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34
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Cernilogar FM, Orlando V. Epigenome programming by Polycomb and Trithorax proteins. Biochem Cell Biol 2005; 83:322-31. [PMID: 15959558 DOI: 10.1139/o05-040] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Polycomb group (PcG) and Trithorax group (TrxG) proteins work, respectively, to maintain repressed or active transcription states of developmentally regulated genes through cell division. Data accumulated in the recent years have increased our understanding of the mechanisms by which PcG and TrxG proteins regulate gene expression. The discovery that histone methylation can serve as a specific mark for PcG and TrxG complexes has provided new insight into the mechanistic function of this cell-memory system.
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Abstract
Gene expression, differentiation and the specialized function of various cell types are controlled epigenetically by post-translational histone modifications. These modifications establish a "histone code" that is recognized by various regulatory proteins, thereby creating a stable pattern of gene expression. The focus of this review is to discuss how the chromatin modifications regulate immunoglobulin gene rearrangement and B cell differentiation.
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Affiliation(s)
- I-hsin Su
- Laboratory of Lymphocyte Signalling, The Rockefeller University, 1230 York Avenue, Box 301, New York, NY 10021, USA.
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36
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Breuer R, Snijders P, Sutedja G, Sewalt R, Otte A, Postmus P, Meijer C, Raaphorst F, Smit E. Expression of the p16INK4a gene product, methylation of the p16INK4a promoter region and expression of the polycomb-group gene BMI-1 in squamous cell lung carcinoma and premalignant endobronchial lesions. Lung Cancer 2005; 48:299-306. [DOI: 10.1016/j.lungcan.2004.11.026] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2004] [Revised: 11/15/2004] [Accepted: 11/23/2004] [Indexed: 10/25/2022]
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Arai S, Miyazaki T. Impaired maturation of myeloid progenitors in mice lacking novel Polycomb group protein MBT-1. EMBO J 2005; 24:1863-73. [PMID: 15889154 PMCID: PMC1142590 DOI: 10.1038/sj.emboj.7600654] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2004] [Accepted: 03/31/2005] [Indexed: 11/08/2022] Open
Abstract
Polycomb group (PcG) proteins participate in DNA-binding complexes with gene-repressing activity, many of which have been highlighted for their involvement in hematopoiesis. We have identified a putative PcG protein, termed MBT-1, that is associated with Rnf2, an in vivo interactor of PcG proteins. MBT-1 structurally resembles the H-L(3)MBT protein, whose deletion is predicted to be responsible for myeloid hematopoietic malignancies. The human MBT-1 gene is located on chromosome 6q23, a region frequently deleted in leukemia cells, and shows a transient expression spike in response to maturation-inducing stimuli in myeloid leukemia cells. MBT-1(-/-) myeloid progenitor cells exhibit a maturational deficiency but maintain normal proliferative activities. This results in the accumulation of immature myeloid progenitors and hence, a marked decrease of mature myeloid blood cells, causing the MBT-1(-/-) mice to die of anemia during a late embryonic stage. Together, we conclude that MBT-1 specifically regulates the maturational advancement of myeloid progenitor cells during transitions between two developmental stages. We also show that MBT-1 appears to influence myelopoiesis by transiently enhancing p57(KIP2) expression levels.
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Affiliation(s)
- Satoko Arai
- Center for Immunology, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Toru Miyazaki
- Center for Immunology, University of Texas Southwestern Medical Center, Dallas, TX, USA
- Center for Immunology, University of Texas Southwestern Medical Center, 6000 Harry Hines Boulevard NA7200, Dallas, TX 75390-9093, USA. Tel.: +1 214 648 7322; Fax: +1 214 648 7331; E-mail:
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38
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Raaphorst FM. Of Mice, Flies, and Man: The Emerging Role of Polycomb-Group Genes in Human Malignant Lymphomas. Int J Hematol 2005; 81:281-7. [PMID: 15914355 DOI: 10.1532/ijh97.05023] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Genes belonging to the Polycomb group (PcG) are responsible for the maintenance of cell identity and are directly involved in epigenetic gene silencing. They perform a vital role in the regulation of embryogenesis but also contribute to various adult processes, including regulation of the cell cycle and lymphopoiesis. Experimental model systems have demonstrated that enhanced expression of individual PcG genes, such as Bmi1, results in the development of B-cell and T-cell lymphomas. In humans, a growing body of work has now linked human PcG genes to various hematologic and epithelial cancers. This review focuses on the emerging role of PcG genes in the development of human malignant lymphomas.
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Affiliation(s)
- Frank M Raaphorst
- Department of Pathology, VU Medical Center, 1081 HV Amsterdam, The Netherlands.
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39
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Breuer RHJ, Snijders PJF, Smit EF, Sutedja TG, Sewalt RGAB, Otte AP, van Kemenade FJ, Postmus PE, Meijer CJLM, Raaphorst FM. Increased expression of the EZH2 polycomb group gene in BMI-1-positive neoplastic cells during bronchial carcinogenesis. Neoplasia 2005; 6:736-43. [PMID: 15720799 PMCID: PMC1531677 DOI: 10.1593/neo.04160] [Citation(s) in RCA: 95] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Polycomb group (PcG) genes are responsible for maintenance of cellular identity and contribute to regulation of the cell cycle. Recent studies have identified several PcG genes as oncogenes, and a role for PcG proteins in human oncogenesis is suspected. We investigated the expression of BMI-1 and EZH2 PcG oncogenes in human bronchial squamous cell carcinomas (SCCs) and bronchial premalignant precursor lesions (PLs). Whereas normal bronchial epithelium was associated with widespread expression of BMI-1 in resting EZH2-negative cells, neoplastic cells in lung carcinomas displayed altered expression of both BMI-1 and EZH2. Two patterns of abnormal PcG expression were observed: increased expression of BMI-1 in dividing neoplastic cells of PLs and SCCs, and enhanced expression of EZH2 and Ki-67 in BMI-1-positive cells according to severity of the histopathologic stage. We propose that altered expression of BMI-1 and EZH2 is an early event that precedes high rates of proliferation in lung cancer. Because PcG complexes are normally involved in the maintenance of cell characteristics, abnormal PcG expression may contribute to loss of cell identity.
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40
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Miyazaki M, Kawamoto H, Kato Y, Itoi M, Miyazaki K, Masuda K, Tashiro S, Ishihara H, Igarashi K, Amagai T, Kanno R, Kanno M. Polycomb group gene mel-18 regulates early T progenitor expansion by maintaining the expression of Hes-1, a target of the Notch pathway. THE JOURNAL OF IMMUNOLOGY 2005; 174:2507-16. [PMID: 15728456 DOI: 10.4049/jimmunol.174.5.2507] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Polycomb group (PcG) proteins play a role in the maintenance of cellular identity throughout many rounds of cell division through the regulation of gene expression. In this report we demonstrate that the loss of the PcG gene mel-18 impairs the expansion of the most immature T progenitor cells at a stage before the rearrangement of the TCR beta-chain gene in vivo and in vitro. This impairment of these T progenitors appears to be associated with increased susceptibility to cell death. We also show that the expression of Hes-1, one of the target genes of the Notch signaling pathway, is drastically down-regulated in early T progenitors isolated from mel-18(-/-) mice. In addition, mel-18(-/-) T precursors could not maintain the Hes-1 expression induced by Delta-like-1 in monolayer culture. Collectively, these data indicate that mel-18 contributes to the maintenance of the active state of the Hes-1 gene as a cellular memory system, thereby supporting the expansion of early T progenitors.
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Affiliation(s)
- Masaki Miyazaki
- Department of Immunology, Graduate School of Biomedical Science, Hiroshima University, Hiroshima, Japan
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41
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Abstract
Development is the process whereby a multipotent cell gives rise, through series of divisions, to progeny with successively restricted potentials. During T cell development, the process begins with a multipotent hematopoietic stem cell (HSC) in the bone marrow, moves to the thymus where early T cells or thymocytes pass through signal-initiated developmental checkpoints, and ends in the periphery where mature T cells reside. At each step along this developmental pathway, T lymphocyte progenitors must be able to turn genes on and off, creating a specialized program of gene expression, to allow further development. How is gene expression coordinated? This review will summarize what has been learned about the function of chromatin structure in generating a "blueprint" of gene expression during T cell development. This will include discussion of mechanisms of chromatin remodeling, histone modification, and heritable gene silencing. In many cases, these processes are carried out by multi-protein complexes whose components are largely ubiquitously expressed. The spatial and temporal specificity of these complexes is contributed by sequence specific DNA binding factors, some of which are cell type restricted in their expression. This review will summarize research underway to identify these key genetic "targeters." Taken together, the research reviewed here provides a glimpse into the importance of regulation of chromatin structure in T cell development and the "players" involved.
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Affiliation(s)
- Susan Winandy
- Department of Microbiology-Immunology, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA.
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42
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MacGrogan D, Kalakonda N, Alvarez S, Scandura JM, Boccuni P, Johansson B, Nimer SD. Structural integrity and expression of the L3MBTL gene in normal and malignant hematopoietic cells. Genes Chromosomes Cancer 2004; 41:203-13. [PMID: 15334543 DOI: 10.1002/gcc.20087] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
The human L3MBTL gene is located in 20q12, a region that is commonly deleted in myeloproliferative disorders (MPD), myelodysplastic syndromes (MDS), and acute myeloid leukemia (AML). L3MBTL is highly homologous to the D-lethal(3) malignant brain tumor [D-l(3)mbt] gene, which is a putative tumor-suppressor gene (TSG) identified in Drosophila and which is closely related to the Drosophila sex combs on midleg (SCM) protein, a member of the Polycomb group (PcG) family of transcriptional repressors. To examine whether L3MBTL functions as a "classic" TSG in human hematologic malignancies, we screened a panel of 17 myeloid leukemia cell lines and peripheral blood or bone marrow samples from 29 MDS and 13 MPD patients for mutations in the entire L3MBTL coding sequence, including intron/exon splice junctions. No mutations were identified, although two single nucleotide differences were found (in intron 14 and in exon 15), which were interpreted as polymorphic changes. We used real-time RT-PCR to quantify the level of L3MBTL mRNA in various normal myeloid and lymphoid cell populations. L3MBTL is expressed in normal CD34+ bone marrow cells, and we found that the pattern of L3MBTL expression was similar to that of BMI1, a well-studied PcG gene with oncogenic activity, suggesting that L3MBTL and BMI1 may be co-regulated during hematopoiesis. The expression of L3MBTL mRNA in 30 of 35 cell lines and 13 of 15 AML samples was comparable to the level of L3MBTL expression in the normal cell populations. However, five leukemia cell lines showed no L3MBTL expression, and two of the AML samples showed aberrant L3MBTL expression. These data suggest that L3MBTL is not mutated in MDS or MPD. However, given the known dosage effects of PcG proteins in regulating gene expression, reduced or absent L3MBTL expression may be relevant in some cases of myeloid leukemia.
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Affiliation(s)
- Donal MacGrogan
- Laboratory of Molecular Aspects of Hematopoiesis, Sloan Kettering Institute, New York, New York 10021, USA
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43
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Abstract
Proteins from the Polycomb group (PcG) are epigenetic chromatin modifiers involved in cancer development and also in the maintenance of embryonic and adult stem cells. The therapeutic potential of stem cells and the growing conviction that tumors contain stem cells highlights the importance of understanding the extrinsic and intrinsic circuitry controlling stem cell fate and their connections to cancer.
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Affiliation(s)
- Merel E Valk-Lingbeek
- The Netherlands Cancer Institute, Department of Molecular Genetics, Plesmanlaan 121, 1066 CX Amsterdam, The Netherlands
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44
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Raaphorst FM, Meijer CJLM, Fieret E, Blokzijl T, Mommers E, Buerger H, Packeisen J, Sewalt RAB, Otte AP, van Diest PJ. Poorly differentiated breast carcinoma is associated with increased expression of the human polycomb group EZH2 gene. Neoplasia 2004; 5:481-8. [PMID: 14965441 PMCID: PMC1502571 DOI: 10.1016/s1476-5586(03)80032-5] [Citation(s) in RCA: 146] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Polycomb group (PcG) genes contribute to the maintenance of cell identity, cell cycle regulation, and oncogenesis. We describe the expression of five PcG genes (BMI-1, RING1, HPC1, HPC2, and EZH2) innormal breast tissues, invasive breast carcinomas, and their precursors. Members of the HPC-HPH/PRC1 PcG complex, including BMI-1, RING1, HPC1, and HPC2, were detected in normal resting and cycling breast cells. The EED-EZH/PRC2 PcG complex protein EZH2 was only found in rare cycling cells, whereas normal resting breast cells were negative for EZH2. PcG gene expression patterns in ductal hyperplasia (DH), well-differentiated ductal carcinoma in situ (DCIS), and well-differentiated invasive carcinomas closely resembled the pattern in healthy cells. However, poorly differentiated DCIS and invasive carcinomas frequently expressed EZH2 in combination with HPC-HPH/PRC1 proteins. Most BMI-1/EZH2 double-positive cells in poorly differentiated DCIS were resting. Poorly differentiated invasive carcinoma displayed an enhanced rate of cell division within BMI-1/EZH2 double-positive cells. We propose that the enhanced expression of EZH2 in BMI-1(+) cells contributes to the loss of cell identity in poorly differentiated breast carcinomas, and that increased EZH2 expression precedes high frequencies of proliferation. These observations suggest that deregulated expression of EZH2 is associated with loss of differentiation and development of poorly differentiated breast cancer in humans.
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Affiliation(s)
- Frank M Raaphorst
- Department of Pathology, VU University Medical Center, BioCentrum Amsterdam, University of Amsterdam, Amsterdam, The Netherlands.
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45
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Dukers DF, van Galen JC, Giroth C, Jansen P, Sewalt RGAB, Otte AP, Kluin-Nelemans HC, Meijer CJLM, Raaphorst FM. Unique polycomb gene expression pattern in Hodgkin's lymphoma and Hodgkin's lymphoma-derived cell lines. THE AMERICAN JOURNAL OF PATHOLOGY 2004; 164:873-81. [PMID: 14982841 PMCID: PMC1613333 DOI: 10.1016/s0002-9440(10)63175-6] [Citation(s) in RCA: 95] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Human Polycomb-group (PcG) genes play a crucial role in the regulation of embryonic development and regulation of the cell cycle and hematopoiesis. PcG genes encode proteins that form two distinct PcG complexes, involved in maintenance of cell identity and gene silencing patterns. We recently showed that expression of the BMI-1 and EZH2 PcG genes is separated during normal B-cell development in germinal centers, whereas Hodgkin/Reed-Sternberg (H/RS) cells co-express BMI-1 and EZH2. In the current study, we used immunohistochemistry and immunofluorescence to determine whether the binding partners of these PcG proteins are also present in H/RS cells and H/RS-derived cell lines. PcG expression profiles were analyzed in combination with expression of the cell cycle inhibitor p16INK4a, because experimental model systems indicate that p16 is a downstream target of Bmi-1. We found that H/RS cells and HL-derived cell lines co-express all core proteins of the two known PcG complexes, including BMI-1, MEL-18, RING1, HPH1, HPC1, and -2, EED, EZH2, YY1, and the HPC2 binding partner, CtBP. Expression of HPC1 has not been found in normal mature B cells and other malignant lymphomas of B-cell origin, suggesting that the PcG expression profile of H/RS is unique. In contrast to Bmi-1 transgenic mice where p16INK4a is down-regulated, 27 of 52 BMI-1POS cases of HL revealed strong nuclear expression of p16INK4a. We propose that abnormal expression of BMI-1 and its binding partners in H/RS cells contributes to development of HL. However, abnormal expression of BMI-1 in HL is not necessarily associated with down-regulation of p16INK4a.
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Affiliation(s)
- Danny F Dukers
- Department of Pathology, Vrije Universiteit University Medical Center (VUMC), Amsterdam, The Netherlands
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46
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Raaphorst FM, Vermeer M, Fieret E, Blokzijl T, Dukers D, Sewalt RGAB, Otte AP, Willemze R, Meijer CJLM. Site-specific expression of polycomb-group genes encoding the HPC-HPH/PRC1 complex in clinically defined primary nodal and cutaneous large B-cell lymphomas. THE AMERICAN JOURNAL OF PATHOLOGY 2004; 164:533-42. [PMID: 14742259 PMCID: PMC1602277 DOI: 10.1016/s0002-9440(10)63143-4] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Polycomb-group (PcG) genes preserve cell identity by gene silencing, and contribute to regulation of lymphopoiesis and malignant transformation. We show that primary nodal large B-cell lymphomas (LBCLs), and secondary cutaneous deposits from such lymphomas, abnormally express the BMI-1, RING1, and HPH1 PcG genes in cycling neoplastic cells. By contrast, tumor cells in primary cutaneous LBCLs lacked BMI-1 expression, whereas RING1 was variably detected. Lack of BMI-1 expression was characteristic for primary cutaneous LBCLs, because other primary extranodal LBCLs originating from brain, testes, and stomach were BMI-1-positive. Expression of HPH1 was rarely detected in primary cutaneous LBCLs of the head or trunk and abundant in primary cutaneous LBCLs of the legs, which fits well with its earlier recognition as a distinct clinical pathological entity with different clinical behavior. We conclude that clinically defined subclasses of primary LBCLs display site-specific abnormal expression patterns of PcG genes of the HPC-HPH/PRC1 PcG complex. Some of these patterns (such as the expression profile of BMI-1) may be diagnostically relevant. We propose that distinct expression profiles of PcG genes results in abnormal formation of HPC-HPH/PRC1 PcG complexes, and that this contributes to lymphomagenesis and different clinical behavior of clinically defined LBCLs.
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Affiliation(s)
- Frank M Raaphorst
- Department of Pathology, Vrije Universiteit Medical Center, Amsterdam, The Netherlands.
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47
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Raaphorst FM. Self-renewal of hematopoietic and leukemic stem cells: a central role for the Polycomb-group gene Bmi-1. Trends Immunol 2004; 24:522-4. [PMID: 14552834 DOI: 10.1016/s1471-4906(03)00241-2] [Citation(s) in RCA: 65] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Self-renewal of hematopoietic stem cells is vital for the sustained daily production of blood cells. Two recent studies have shown that the Polycomb-group gene Bmi-1 is indispensable for regulation of self-renewal by normal and leukemic stem cells. This identifies Polycomb-group genes as potential targets for therapeutic intervention in leukemia, and possibly other forms of cancer.
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Affiliation(s)
- Frank M Raaphorst
- Department of Pathology, VU Medical Center, De Boelelaan 1117, 1081 HV Amsterdam, The Netherlands.
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48
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Witte V, Laffert B, Rosorius O, Lischka P, Blume K, Galler G, Stilper A, Willbold D, D'Aloja P, Sixt M, Kolanus J, Ott M, Kolanus W, Schuler G, Baur AS. HIV-1 Nef Mimics an Integrin Receptor Signal that Recruits the Polycomb Group Protein Eed to the Plasma Membrane. Mol Cell 2004; 13:179-90. [PMID: 14759364 DOI: 10.1016/s1097-2765(04)00004-8] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2003] [Revised: 11/20/2003] [Accepted: 12/01/2003] [Indexed: 11/17/2022]
Abstract
The Nef protein of human and simian immunodeficiency virus (HIV/SIV) is believed to interfere with T cell activation signals by forming a signaling complex at the plasma membrane. Composition and function of the complex are not fully understood. Here we report that Nef recruits the Polycomb Group (PcG) protein Eed, so far known as a nuclear factor and repressor of transcription, to the membrane of cells. The Nef-induced translocation of Eed led to a potent stimulation of Tat-dependent HIV transcription, implying that Eed removal from the nucleus is required for optimal Tat function. Similar to Nef action, activation of integrin receptors recruited Eed to the plasma membrane, also leading to enhanced Tat/Nef-mediated transcription. Our results suggest a link between membrane-associated activation processes and transcriptional derepression and demonstrate how HIV exploits this mechanism.
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Affiliation(s)
- Vanessa Witte
- Department of Dermatology, University of Erlangen/Nürnberg, 91052 Erlangen, Germany
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49
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Sánchez-Beato M, Sánchez E, García JF, Pérez-Rosado A, Montoya MC, Fraga M, Artiga MJ, Navarrete M, Abraira V, Morente M, Esteller M, Koseki H, Vidal M, Piris MA. Abnormal PcG protein expression in Hodgkin's lymphoma. Relation with E2F6 and NFκB transcription factors. J Pathol 2004; 204:528-37. [PMID: 15470680 DOI: 10.1002/path.1661] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The Polycomb group (PcG) of proteins comprises a family of repressors of homeobox genes that play key roles in body formation, haematopoiesis and cell cycle control. In this study, a large-scale analysis of PcG protein expression (BMI1, MEL18, PH1, RNF2, RING1, and RYBP) was performed in 321 Hodgkin's lymphoma (HL) biopsies and in reactive lymphoid tissues using tissue microarrays. The relevance of PcG proteins in HL was also investigated by the simultaneous analysis of PcG and other proteins involved in the control of cell cycle, transcription machinery and lymphoid differentiation. The analysis revealed increased expression of a set of PcG proteins (particularly RYBP and BMI1) in tumour cells in comparison with reactive lymphoid tissue. One of the most striking findings was anomalous RYBP expression in 55% of classical HL cases associated with an unfavourable response to treatment and shorter survival. The data obtained in this study also show an association of PcG proteins with E2F6 and NFkappaB transcription factors. The statistical relationship between PcG and NFkappaB activation was further explored in HL-derived cell lines treated with curcumin, an NFkappaB inhibitor, and TNFalpha. Up- or downregulation of MEL18 was paralleled by loss or gain of activated NFkappaB, which suggests that NFkappaB may regulate expression of this protein. Investigation of the relationship between E2F6 and RING1 by immunofluorescence and confocal analysis, in HL cell lines and paraffin sections, revealed co-expression of both proteins in the same tumour cells. These results allow us to propose that the formation of transcription complexes with E2F6 may modify the functional status of PcG proteins in HSR cells.
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Affiliation(s)
- Margarita Sánchez-Beato
- Molecular Pathology Programme, Centro Nacional de Investigaciones Oncológicas (CNIO), C/Melchor Fernández Almagro 3, E-28029 Madrid, Spain.
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50
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Abstract
Hematopoietic stem cells (HSCs) are at the forefront of both basic stem cell research and clinical applications. Regenerative medicine has recently become a viable form of therapy and can potentially cure several diseases. The generation of blood cells from embryonic stem cells and the manipulation of HSCs continue to provide insights into other stem cell systems. The importance of HSCs as a model of an ideal source for cell therapy is increasing.
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Affiliation(s)
- Toru Nakano
- Department of Molecular Cell Biology, Research Institute for Microbial Diseases, Osaka University, 3-1 Yamada-oka, Suita, 565-0871, Osaka, Japan.
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