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New insights into transcriptional and leukemogenic mechanisms of AML1-ETO and E2A fusion proteins. ACTA ACUST UNITED AC 2016; 11:285-304. [PMID: 28261265 DOI: 10.1007/s11515-016-1415-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
BACKGROUND Nearly 15% of acute myeloid leukemia (AML) cases are caused by aberrant expression of AML1-ETO, a fusion protein generated by the t(8;21) chromosomal translocation. Since its discovery, AML1-ETO has served as a prototype to understand how leukemia fusion proteins deregulate transcription to promote leukemogenesis. Another leukemia fusion protein, E2A-Pbx1, generated by the t(1;19) translocation, is involved in acute lymphoblastic leukemias (ALLs). While AML1-ETO and E2A-Pbx1 are structurally unrelated fusion proteins, we have recently shown that a common axis, the ETO/E-protein interaction, is involved in the regulation of both fusion proteins, underscoring the importance of studying protein-protein interactions in elucidating the mechanisms of leukemia fusion proteins. OBJECTIVE In this review, we aim to summarize these new developments while also providing a historic overview of the related early studies. METHODS A total of 218 publications were reviewed in this article, a majority of which were published after 2004.We also downloaded 3D structures of AML1-ETO domains from Protein Data Bank and provided a systematic summary of their structures. RESULTS By reviewing the literature, we summarized early and recent findings on AML1-ETO, including its protein-protein interactions, transcriptional and leukemogenic mechanisms, as well as the recently reported involvement of ETO family corepressors in regulating the function of E2A-Pbx1. CONCLUSION While the recent development in genomic and structural studies has clearly demonstrated that the fusion proteins function by directly regulating transcription, a further understanding of the underlying mechanisms, including crosstalk with other transcription factors and cofactors, and the protein-protein interactions in the context of native proteins, may be necessary for the development of highly targeted drugs for leukemia therapy.
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Kikuchi H, Nakayama M, Kuribayashi F, Mimuro H, Imajoh-Ohmi S, Nishitoh H, Takami Y, Nakayama T. Paired box gene 5 isoforms A and B have different functions in transcriptional regulation of B cell development-related genes in immature B cells. Microbiol Immunol 2016; 59:426-31. [PMID: 26094714 DOI: 10.1111/1348-0421.12272] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2015] [Revised: 06/03/2015] [Accepted: 06/04/2015] [Indexed: 12/26/2022]
Abstract
The transcription factor paired box gene 5 (Pax5) is essential for B cell development. In this study, complementation analyses in Pax5-deficient DT40 cells showed that three Pax5 isoforms Pax5A, Pax5B and Pax5BΔEx8 (another spliced isoform of Pax5B lacking exon 8) exhibit distinct roles in transcriptional regulation of six B cell development-related genes (activation-induced cytidine deaminase, Aiolos, BTB and CNC homology 2, B cell lymphoma-6, early B cell factor 1, origin binding factor-1 genes), transcriptions of which are remarkably down-regulated by Pax5-deficiency. Moreover, ectopic expression study shows that these Pax5 isoforms may regulate themselves and each other at the transcriptional level.
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Affiliation(s)
- Hidehiko Kikuchi
- Section of Biochemistry and Molecular Biology, Department of Medical Sciences, Faculty of Medicine, University of Miyazaki, 5200, Kihara, Kiyotake, Miyazaki 889-1692.,Division of Bacteriology, Department of Infectious Diseases Control, International Research Center for Infectious Diseases, Institute of Medical Science, University of Tokyo, 4-6-1 Shirokanedai, Minato-ku, Tokyo 108-8639
| | - Masami Nakayama
- Section of Biochemistry and Molecular Biology, Department of Medical Sciences, Faculty of Medicine, University of Miyazaki, 5200, Kihara, Kiyotake, Miyazaki 889-1692
| | - Futoshi Kuribayashi
- Division of Bacteriology, Department of Infectious Diseases Control, International Research Center for Infectious Diseases, Institute of Medical Science, University of Tokyo, 4-6-1 Shirokanedai, Minato-ku, Tokyo 108-8639.,Department of Biochemistry, Kawasaki Medical School, 577, Matsushima, Kurashiki, Okayama 701-0192
| | - Hitomi Mimuro
- Division of Bacteriology, Department of Infectious Diseases Control, International Research Center for Infectious Diseases, Institute of Medical Science, University of Tokyo, 4-6-1 Shirokanedai, Minato-ku, Tokyo 108-8639
| | - Shinobu Imajoh-Ohmi
- Laboratory Center for Proteomics Research, Graduate School of Frontier Sciences, Institute of Medical Science, University of Tokyo, 4-6-1 Shirokanedai, Minato-ku, Tokyo 108-8639, Japan
| | - Hideki Nishitoh
- Section of Biochemistry and Molecular Biology, Department of Medical Sciences, Faculty of Medicine, University of Miyazaki, 5200, Kihara, Kiyotake, Miyazaki 889-1692
| | - Yasunari Takami
- Section of Biochemistry and Molecular Biology, Department of Medical Sciences, Faculty of Medicine, University of Miyazaki, 5200, Kihara, Kiyotake, Miyazaki 889-1692
| | - Tatsuo Nakayama
- Section of Biochemistry and Molecular Biology, Department of Medical Sciences, Faculty of Medicine, University of Miyazaki, 5200, Kihara, Kiyotake, Miyazaki 889-1692
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Prolactin levels correlate with abnormal B cell maturation in MRL and MRL/lpr mouse models of systemic lupus erythematosus-like disease. Clin Dev Immunol 2013; 2013:287469. [PMID: 24454471 PMCID: PMC3878598 DOI: 10.1155/2013/287469] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2013] [Accepted: 09/22/2013] [Indexed: 12/15/2022]
Abstract
Prolactin (PRL) plays an important role in modulating the immune response. In B cells, PRL enhances antibody production, including antibodies with self-specificity. In this study, our aims were to determine the level of PRL receptor expression during bone-marrow B-cell development and to assess whether the presence of high PRL serum concentrations influences absolute numbers of developing populations and disease outcome in lupus-prone murine models. We observed that the PRL-receptor is expressed in early bone-marrow B-cell; the expression in lupus-prone mice, which had the highest level of expression in pro-B cells and immature cells, differed from that in wild-type mice. These expression levels did not significantly change in response to hyperprolactinemia; however, populations of pro-B and immature cells from lupus-prone strains showed a decrease in the absolute numbers of cells with high PRL-receptor expression in response to PRL. Because immature self-reactive B cells are constantly being eliminated, we assessed the expression of survival factor BIRC5, which is more highly expressed in both pro-B and immature B-cells in response to PRL and correlates with the onset of disease. These results identify an important role of PRL in the early stages of the B-cell maturation process: PRL may promote the survival of self-reactive clones.
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Kikuchi H, Nakayama M, Takami Y, Kuribayashi F, Nakayama T. EBF1 acts as a powerful repressor of Blimp-1 gene expression in immature B cells. Biochem Biophys Res Commun 2012; 422:780-5. [PMID: 22634309 DOI: 10.1016/j.bbrc.2012.05.099] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2012] [Accepted: 05/17/2012] [Indexed: 01/09/2023]
Abstract
The transcription factor, early B cell factor 1 (EBF1) with an atypical zinc-finger and helix-loop-helix motif, is essential for development and differentiation of lymphocytes. In mice, EBF1 is involved in the generation of pre-pro B cells (the first specified progenitors of B cells) from common lymphoid progenitors (CLPs) and transcription regulations of various genes involved in B cell-development, for instance, mb-1 and Pax5. During B lymphopoiesis, interestingly, EBF1 is detected throughout from CLPs to mature B cells. However, in immature B cells, the physiological role of EBF1 remains to be elucidated. Here, by analyzing EBF1-deficient DT40 cells, EBF1(-/-), generated by us, we show that EBF1-deficiency caused significant increases (to ∼800%) in both mRNA and protein levels of B lymphocyte-induced maturation protein-1 (Blimp-1), the master gene for plasma cell differentiation. In addition, both transcription and protein synthesis of Blimp-1 were remarkably down-regulated (to ∼20%) by re-expression (over-expression) of EBF1. Chromatin immunoprecipitation assay revealed that EBF1 binds to proximal 5'-upstream regions around two putative EBF1 binding motifs of the gene in vivo. These results suggest that EBF1 takes part in transcriptional regulations of the Blimp-1 gene in immature B cells, and may play a key role in B cell differentiation. This is the first report on a novel EBF1 function in immature B cells as a powerful repressor of Blimp-1 gene expression.
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Affiliation(s)
- Hidehiko Kikuchi
- Section of Biochemistry and Molecular Biology, Department of Medical Sciences, Miyazaki Medical College, University of Miyazaki, 5200 Kihara, Kiyotake, Miyazaki 889-1692, Japan.
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Kikuchi H, Nakayama M, Takami Y, Kuribayashi F, Nakayama T. Possible involvement of Helios in controlling the immature B cell functions via transcriptional regulation of protein kinase Cs. RESULTS IN IMMUNOLOGY 2011; 1:88-94. [PMID: 24371557 DOI: 10.1016/j.rinim.2011.11.002] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/03/2011] [Revised: 11/09/2011] [Accepted: 11/09/2011] [Indexed: 01/10/2023]
Abstract
The transcription factor Ikaros family consists of five zinc-finger proteins: Ikaros, Aiolos, Helios, Eos and Pegasus; these proteins except Pegasus are essential for development and differentiation of lymphocytes. However, in B lymphocytes, the physiological role of Helios remains to be elucidated yet, because its expression level is very low. Here, we generated the Helios-deficient DT40 cells, Helios (-/-), and showed that the Helios-deficiency caused significant increases in transcriptions of four protein kinase Cs (PKCs); PKC-δ, PKC-ε, PKC-η and PKC-ζ, whereas their expressions were drastically down-regulated in the Aiolos-deficient DT40 cells, Aiolos (-/-). In addition, Helios (-/-) was remarkably resistant against phorbol 12-myristate 13-acetate (PMA)/ionomycin treatment, which mimics the B cell receptor (BCR)-mediated stimulation. In the presence of PMA/ionomycin, their viability was remarkably higher than that of DT40, and their DNA fragmentation was less severe than that of DT40 in the opposite manner for the Aiolos-deficiency. The resistance against the PMA/ionomycin-induced apoptosis of Helios (-/-) was sensitive to Rottlerin but not to Go6976. In addition, the Helios-deficiency caused remarkable up-regulation of the Rottlerin-sensitive superoxide (O2 (-))-generating activity. These data suggest that Helios may contribute to the regulation of the BCR-mediated apoptosis and O2 (-)-generating activity, via transcriptional regulation of these four PKCs (especially PKC-δ) in immature B lymphocytes. Together with previous data, our findings may significantly help in the understanding of the B lymphocyte-specific expressions of PKC genes and molecular mechanisms of both the BCR-mediated apoptosis involved in negative selection and the O2 (-)-generating system in immature B lymphocytes.
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Affiliation(s)
- Hidehiko Kikuchi
- Section of Biochemistry and Molecular Biology, Department of Medical Sciences, Miyazaki Medical College, University of Miyazaki, 5200 Kihara, Kiyotake, Miyazaki 889-1692, Japan
| | - Masami Nakayama
- Section of Biochemistry and Molecular Biology, Department of Medical Sciences, Miyazaki Medical College, University of Miyazaki, 5200 Kihara, Kiyotake, Miyazaki 889-1692, Japan
| | - Yasunari Takami
- Section of Biochemistry and Molecular Biology, Department of Medical Sciences, Miyazaki Medical College, University of Miyazaki, 5200 Kihara, Kiyotake, Miyazaki 889-1692, Japan
| | - Futoshi Kuribayashi
- Department of Biochemistry, Kawasaki Medical School, Kurashiki, Okayama 701-0192, Japan
| | - Tatsuo Nakayama
- Section of Biochemistry and Molecular Biology, Department of Medical Sciences, Miyazaki Medical College, University of Miyazaki, 5200 Kihara, Kiyotake, Miyazaki 889-1692, Japan
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Kikuchi H, Kuribayashi F, Takami Y, Imajoh-Ohmi S, Nakayama T. GCN5 regulates the activation of PI3K/Akt survival pathway in B cells exposed to oxidative stress via controlling gene expressions of Syk and Btk. Biochem Biophys Res Commun 2011; 405:657-61. [DOI: 10.1016/j.bbrc.2011.01.088] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2011] [Accepted: 01/25/2011] [Indexed: 01/08/2023]
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Kikuchi H, Kuribayashi F, Kiwaki N, Nakayama T. Curcumin dramatically enhances retinoic acid-induced superoxide generating activity via accumulation of p47-phox and p67-phox proteins in U937 cells. Biochem Biophys Res Commun 2010; 395:61-5. [PMID: 20346917 DOI: 10.1016/j.bbrc.2010.03.136] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2010] [Accepted: 03/20/2010] [Indexed: 11/19/2022]
Abstract
The membrane bound cytochrome b558 composed of large gp91-phox and small p22-phox subunits, and cytosolic proteins p40-, p47- and p67-phox are important components of superoxide (O(2)(-))-generating system in phagocytes and B lymphocytes. A lack of this system in phagocytes is known to cause serious life-threatening infections. Here, we describe that curcumin, a polyphenol responsible for the yellow color of curry spice turmeric, dramatically activates the O(2)(-)-generating system during retinoic acid (RA)-induced differentiation of human monoblastic leukemia U937 cells to macrophage-like cells. When U937 cells were cultured in the presence of RA and curcumin, the O(2)(-)-generating activity increased more than 4-fold compared with that in the absence of the latter. Semiquantitative RT-PCR showed that co-treatment with RA and curcumin slightly enhanced gene expressions of the five components compared with those of the RA-treatment only. On the other hand, immunoblot analysis revealed that co-treatment with RA and curcumin caused remarkable accumulation of protein levels of p47-phox (to 7-fold) and p67-phox (to 4-fold) compared with those of the RA-treatment alone. These results suggested that curcumin dramatically enhances RA-induced O(2)(-)-generating activity via accumulation of cytosolic p47-phox and p67-phox proteins in U937 cells. Therefore, it should have the potential as an effective modifier in therapy of leukemia and/or as an immunopotentiator.
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Affiliation(s)
- Hidehiko Kikuchi
- Department of Life Science, Frontier Science Research Center, University of Miyazaki, Kiyotake, Miyazaki 889-1692, Japan
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Lacking of Aiolos accelerates pre-mature B cell apoptosis mediated by BCR signaling through elevation in cytochrome c release. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2009; 1793:1304-14. [DOI: 10.1016/j.bbamcr.2009.04.016] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/15/2009] [Revised: 04/20/2009] [Accepted: 04/27/2009] [Indexed: 01/12/2023]
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