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Qiu X, He H, Zeng H, Tong X, Zhang C, Liu Y, Liao Z, Liu Q. Integrative transcriptome analysis identifies MYBL2 as a poor prognosis marker for osteosarcoma and a pan-cancer marker of immune infiltration. Genes Dis 2024; 11:101004. [PMID: 38292182 PMCID: PMC10825309 DOI: 10.1016/j.gendis.2023.04.035] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2022] [Revised: 03/23/2023] [Accepted: 04/29/2023] [Indexed: 02/01/2024] Open
Abstract
MYBL2 (MYB proto-oncogene like 2) is an emerging prognostic marker for malignant tumors, and its potential role in osteosarcoma and its relationship with immune infiltration in pan-cancer is yet to be elucidated. We constructed a transcription factor activity profile of osteosarcoma using the single-cell regulatory network inference algorithm based on single-cell RNA sequencing data obtained from the Gene Expression Omnibus. Subsequently, we calculated the extent of MYBL2 activation in malignant proliferative osteoblasts. We also explored the association between MYBL2 and chemotherapy resistance in osteosarcoma. Furthermore, we systematically correlated MYBL2 with immunological signatures in the tumor microenvironment in pan-cancer, including immune cell infiltration, immune checkpoints, and tumor immunotherapy prognosis. Finally, we developed and validated a risk score (MRGS), derived an osteosarcoma risk score nomogram based on MRGS, and tested its ability to predict prognosis. MYBL2 and gene enrichment analyses in osteosarcoma and pan-cancer revealed that MYBL2 was positively correlated with cell proliferation and tumor immune pathways. MYBL2 expression positively correlated with SLC19A1 in pan-cancer and osteosarcoma cell lines. Pan-cancer immune infiltration analysis revealed that MYBL2 was correlated with myeloid-derived suppressor cells, Th2 cell infiltration, CD276, RELT gene expression, and tumor mutation burden. In summary, MYBL2 regulates proliferation, progression, and immune infiltration in osteosarcoma and pan-cancer. Therefore, we found that MYBL2 could be used as a potential marker for predicting the osteosarcoma prognosis. Patients with osteosarcoma and high MYBL2 expression are theoretically more sensitive to methotrexate. An osteosarcoma prognostic nomogram can provide new ideas in the search for osteosarcoma prognostic markers.
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Affiliation(s)
- Xinzhu Qiu
- Department of Orthopaedics, Xiangya Hospital, Central South University, Changsha, Hunan 410008, China
- National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Changsha, Hunan 410008, China
- Department of Sports Medicine, Research Center of Sports Medicine, Xiangya Hospital, Central South University, Changsha, Hunan 410008, China
| | - Hongbo He
- Department of Orthopaedics, Xiangya Hospital, Central South University, Changsha, Hunan 410008, China
- National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Changsha, Hunan 410008, China
| | - Hao Zeng
- Department of Orthopaedics, Xiangya Hospital, Central South University, Changsha, Hunan 410008, China
- National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Changsha, Hunan 410008, China
| | - Xiaopeng Tong
- Department of Orthopaedics, Xiangya Hospital, Central South University, Changsha, Hunan 410008, China
- National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Changsha, Hunan 410008, China
- Department of Sports Medicine, Research Center of Sports Medicine, Xiangya Hospital, Central South University, Changsha, Hunan 410008, China
| | - Can Zhang
- Department of Orthopaedics, Xiangya Hospital, Central South University, Changsha, Hunan 410008, China
- National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Changsha, Hunan 410008, China
| | - Yupeng Liu
- Department of Orthopaedics, Xiangya Hospital, Central South University, Changsha, Hunan 410008, China
- National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Changsha, Hunan 410008, China
| | - Zhan Liao
- Department of Orthopaedics, Xiangya Hospital, Central South University, Changsha, Hunan 410008, China
- National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Changsha, Hunan 410008, China
| | - Qing Liu
- Department of Orthopaedics, Xiangya Hospital, Central South University, Changsha, Hunan 410008, China
- National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Changsha, Hunan 410008, China
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Pérez-Aguilar B, Marquardt JU, Muñoz-Delgado E, López-Durán RM, Gutiérrez-Ruiz MC, Gomez-Quiroz LE, Gómez-Olivares JL. Changes in the Acetylcholinesterase Enzymatic Activity in Tumor Development and Progression. Cancers (Basel) 2023; 15:4629. [PMID: 37760598 PMCID: PMC10526250 DOI: 10.3390/cancers15184629] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2023] [Revised: 08/22/2023] [Accepted: 08/23/2023] [Indexed: 09/29/2023] Open
Abstract
Acetylcholinesterase is a well-known protein because of the relevance of its enzymatic activity in the hydrolysis of acetylcholine in nerve transmission. In addition to the catalytic action, it exerts non-catalytic functions; one is associated with apoptosis, in which acetylcholinesterase could significantly impact the survival and aggressiveness observed in cancer. The participation of AChE as part of the apoptosome could explain the role in tumors, since a lower AChE content would increase cell survival due to poor apoptosome assembly. Likewise, the high Ach content caused by the reduction in enzymatic activity could induce cell survival mediated by the overactivation of acetylcholine receptors (AChR) that activate anti-apoptotic pathways. On the other hand, in tumors in which high enzymatic activity has been observed, AChE could be playing a different role in the aggressiveness of cancer; in this review, we propose that AChE could have a pro-inflammatory role, since the high enzyme content would cause a decrease in ACh, which has also been shown to have anti-inflammatory properties, as discussed in this review. In this review, we analyze the changes that the enzyme could display in different tumors and consider the different levels of regulation that the acetylcholinesterase undergoes in the control of epigenetic changes in the mRNA expression and changes in the enzymatic activity and its molecular forms. We focused on explaining the relationship between acetylcholinesterase expression and its activity in the biology of various tumors. We present up-to-date knowledge regarding this fascinating enzyme that is positioned as a remarkable target for cancer treatment.
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Affiliation(s)
- Benjamín Pérez-Aguilar
- Area de Medicina Experimental y Traslacional, Departamento de Ciencias de la Salud, Universidad Autónoma Metropolitana, Unidad Iztapalapa, Mexico City 09310, Mexico; (B.P.-A.); (M.C.G.-R.)
- Department of Medicine I, University of Lübeck, 23562 Lübeck, Germany;
| | - Jens U. Marquardt
- Department of Medicine I, University of Lübeck, 23562 Lübeck, Germany;
| | | | - Rosa María López-Durán
- Laboratorio de Biomembranas, Departamento de Ciencias de la Salud, Universidad Autónoma Metropolitana, Unidad Iztapalapa, Mexico City 09310, Mexico;
| | - María Concepción Gutiérrez-Ruiz
- Area de Medicina Experimental y Traslacional, Departamento de Ciencias de la Salud, Universidad Autónoma Metropolitana, Unidad Iztapalapa, Mexico City 09310, Mexico; (B.P.-A.); (M.C.G.-R.)
| | - Luis E. Gomez-Quiroz
- Area de Medicina Experimental y Traslacional, Departamento de Ciencias de la Salud, Universidad Autónoma Metropolitana, Unidad Iztapalapa, Mexico City 09310, Mexico; (B.P.-A.); (M.C.G.-R.)
| | - José Luis Gómez-Olivares
- Laboratorio de Biomembranas, Departamento de Ciencias de la Salud, Universidad Autónoma Metropolitana, Unidad Iztapalapa, Mexico City 09310, Mexico;
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Yu H, Hua Y, He Y, Wang Y, Hu X, Chen S, Liu J, Yang J, Li H. Sustained Release of MiR-217 Inhibitor by Nanoparticles Facilitates MSC-Mediated Attenuation of Neointimal Hyperplasia After Vascular Injury. Front Cardiovasc Med 2021; 8:739107. [PMID: 34708092 PMCID: PMC8542691 DOI: 10.3389/fcvm.2021.739107] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2021] [Accepted: 09/13/2021] [Indexed: 01/05/2023] Open
Abstract
Mesenchymal stem cells (MSCs) have been proven capable of differentiating into endothelial cells (ECs) and increasing vascular density in mouse ischemia models. However, the therapeutic potential of MSCs in neointimal hyperplasia after vascular injury is still not fully understood. In this study, we proposed that sustained release of miR-217 inhibitor encapsulated by nanoparticles in MSCs can enhance the therapeutic effects of MSCs on alleviating neointimal hyperplasia in a standard mouse wire injury model. We intravenously administered MSCs to mice with injured arteries and examined neointimal proliferation, endothelial differentiation and senescence. We demonstrated that MSCs localized to the luminal surface of the injured artery within 24 h after injection and subsequently differentiated into endothelial cells, inhibited neointimal proliferation and migration of vascular smooth muscle cells. Transfection of MSCs with poly lactic-co-glycolic acid nanoparticles (PLGA-NP) encapsulating an miR-217 agomir abolished endothelial differentiation as well as the therapeutic effect of MSCs. On the contrary, silencing of endogenous miR-217 improved the therapeutic efficacy of MSCs. Our study provides a new strategy of augmenting the therapeutic potency of MSCs in treatment of vascular injury.
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Affiliation(s)
- Hong Yu
- Department of Otorhinolaryngology, Tongji Medical College, Union Hospital, Huazhong University of Science and Technology, Wuhan, China
| | - Yutao Hua
- Department of Medicine, University of Alabama at Birmingham, Birmingham, AL, United States
| | - Yecheng He
- Department of Clinical Medicine, Suzhou Vocational Health College, Suzhou, China
| | - Yin Wang
- Department of Cardiovascular Surgery, Tongji Medical College, Union Hospital, Huazhong University of Science and Technology, Wuhan, China
| | - Xingjian Hu
- Department of Cardiovascular Surgery, Tongji Medical College, Union Hospital, Huazhong University of Science and Technology, Wuhan, China
| | - Si Chen
- Department of Cardiovascular Surgery, Tongji Medical College, Union Hospital, Huazhong University of Science and Technology, Wuhan, China
| | - Junwei Liu
- Department of Cardiovascular Surgery, Tongji Medical College, Union Hospital, Huazhong University of Science and Technology, Wuhan, China
| | - Junjie Yang
- Department of Anesthesiology, University of Maryland School of Medicine, Baltimore, MD, United States
| | - Huadong Li
- Department of Cardiovascular Surgery, Tongji Medical College, Union Hospital, Huazhong University of Science and Technology, Wuhan, China
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Intracellular Reactive Oxygen Species Mediate the Therapeutic Effect of Induced Pluripotent Stem Cells for Acute Kidney Injury. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2020; 2020:1609638. [PMID: 32308798 PMCID: PMC7136790 DOI: 10.1155/2020/1609638] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/17/2019] [Revised: 02/03/2020] [Accepted: 02/19/2020] [Indexed: 11/17/2022]
Abstract
Aims Treatment for acute kidney injury (AKI) is challenging. Induced pluripotent stem cells (iPSCs) have great therapeutic potential. This study sought to determine whether iPSCs attenuate AKI and the role of reactive oxygen species (ROS). Results We intravenously injected isogenic iPSCs into mice 2 h after renal ischemia-reperfusion injury (IRI). The cells were selectively trafficked to ischemia/reperfusion-injured kidney where they decreased kidney ROS and inflammatory cytokines and improved kidney function and morphology. Pretreating the cells with ROS inhibitors before administration decreased iPSC engraftment and abolished the protective effect of iPSCs. In contrast, pretreating iPSCs with hydrogen peroxide increased iPSC engraftment and therapeutic effect. Although the intravenously administered iPSCs trafficked to the IRI kidney, the cells did not differentiate into proximal or distal tubular epithelial cells. In vitro, the capabilities of the iPSC-released substances to promote proliferation and decrease apoptosis of renal epithelial cells were increased by ROS pretreatment of iPSCs. Moreover, pretreatment of the iPSCs with ROS inhibitor had the opposite effect. Similarly, moderate concentrations of ROS increased while ROS inhibitors decreased iPSC mobility, adhesion to the extracellular matrix, and mitochondrial metabolism. Innovation and Conclusion. iPSCs decreased renal ischemia/reperfusion injury mainly through iPSC-released substances. The therapeutic effect, mitochondrial metabolism, mobility, and kidney trafficking of iPSCs were ROS dependent.
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MYBL2 (B-Myb): a central regulator of cell proliferation, cell survival and differentiation involved in tumorigenesis. Cell Death Dis 2017. [PMID: 28640249 PMCID: PMC5520903 DOI: 10.1038/cddis.2017.244] [Citation(s) in RCA: 196] [Impact Index Per Article: 28.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Limitless cell proliferation, evasion from apoptosis, dedifferentiation, metastatic spread and therapy resistance: all these properties of a cancer cell contribute to its malignant phenotype and affect patient outcome. MYBL2 (alias B-Myb) is a transcription factor of the MYB transcription factor family and a physiological regulator of cell cycle progression, cell survival and cell differentiation. When deregulated in cancer cells, MYBL2 mediates the deregulation of these properties. In fact, MYBL2 is overexpressed and associated with poor patient outcome in numerous cancer entities. MYBL2 and players of its downstream transcriptional network can be used as prognostic and/or predictive biomarkers as well as potential therapeutic targets to offer less toxic and more specific anti-cancer therapies in future. In this review, we summarize current knowledge on the physiological roles of MYBL2 and highlight the impact of its deregulation on cancer initiation and progression.
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Wu Y, Zhang X, Kang X, Li N, Wang R, Hu T, Xiang M, Wang X, Yuan W, Chen A, Meng D, Chen S. Oxidative stress inhibits adhesion and transendothelial migration, and induces apoptosis and senescence of induced pluripotent stem cells. Clin Exp Pharmacol Physiol 2013; 40:626-34. [DOI: 10.1111/1440-1681.12141] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2013] [Revised: 05/30/2013] [Accepted: 06/07/2013] [Indexed: 12/25/2022]
Affiliation(s)
- Yi Wu
- Department of Physiology and Pathophysiology; Fudan University Shanghai Medical College; Shanghai China
- Department of Physiology; Ningxia Medical College; Yinchuan Ningxia China
| | - Xueqing Zhang
- Department of Physiology and Pathophysiology; Fudan University Shanghai Medical College; Shanghai China
| | - Xueling Kang
- Department of Physiology and Pathophysiology; Fudan University Shanghai Medical College; Shanghai China
| | - Ning Li
- Department of Physiology and Pathophysiology; Fudan University Shanghai Medical College; Shanghai China
| | - Rong Wang
- Department of Physiology; Ningxia Medical College; Yinchuan Ningxia China
| | - Tiantian Hu
- Department of Physiology; Ningxia Medical College; Yinchuan Ningxia China
| | - Meng Xiang
- Department of Physiology and Pathophysiology; Fudan University Shanghai Medical College; Shanghai China
| | - Xinhong Wang
- Department of Physiology and Pathophysiology; Fudan University Shanghai Medical College; Shanghai China
| | - Wenjun Yuan
- Department of Physiology; Ningxia Medical College; Yinchuan Ningxia China
| | - Alex Chen
- Department of Physiology and Pathophysiology; Fudan University Shanghai Medical College; Shanghai China
| | - Dan Meng
- Department of Physiology and Pathophysiology; Fudan University Shanghai Medical College; Shanghai China
| | - Sifeng Chen
- Department of Physiology and Pathophysiology; Fudan University Shanghai Medical College; Shanghai China
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O'Brien RN, Shen Z, Tachikawa K, Lee PA, Briggs SP. Quantitative proteome analysis of pluripotent cells by iTRAQ mass tagging reveals post-transcriptional regulation of proteins required for ES cell self-renewal. Mol Cell Proteomics 2010; 9:2238-51. [PMID: 20513800 DOI: 10.1074/mcp.m110.000281] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Embryonic stem cells and embryonal carcinoma cells share two key characteristics: pluripotency (the ability to differentiate into endoderm, ectoderm, and mesoderm) and self-renewal (the ability to grow without change in an untransformed, euploid state). Much has been done to identify and characterize transcription factors that are necessary or sufficient to maintain these characteristics. Oct-4 and Nanog are necessary to maintain pluripotency; they are down-regulated at the mRNA level by differentiation. There may be additional regulatory genes whose mRNA levels are unchanged but whose proteins are destabilized during differentiation. We generated proteome-wide, quantitative profiles of ES and embryonal carcinoma cells during differentiation, replicating a microarray-based study by Aiba et al. (Aiba, K., Sharov, A. A., Carter, M. G., Foroni, C., Vescovi, A. L., and Ko, M. S. (2006) Defining a developmental path to neural fate by global expression profiling of mouse embryonic stem cells and adult neural stem/progenitor cells. Stem Cells 24, 889-895) who triggered differentiation by treatment with 1 μM all-trans-retinoic acid. We identified several proteins whose levels decreased during differentiation in both cell types but whose mRNA levels were unchanged. We confirmed several of these cases by RT-PCR and Western blot. Racgap1 (also known as mgcRacgap) was particularly interesting because it is required for viability of preimplantation embryos and hematopoietic stem cells, and it is also required for differentiation. To confirm our observation that RACGAP-1 declines during retinoic acid-mediated differentiation, we used multiple reaction monitoring, a targeted mass spectrometry-based quantitation method, and determined that RACGAP-1 levels decline by half during retinoic acid-mediated differentiation. We knocked down Racgap-1 mRNA levels using a panel of five shRNAs. This resulted in a loss of self-renewal that correlated with the level of knockdown. We conclude that RACGAP-1 is post-transcriptionally regulated during blastocyst development to enable differentiation by inhibiting ES cell self-renewal.
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Affiliation(s)
- Robert N O'Brien
- Division of Biological Sciences, University of California San Diego, La Jolla, California 92093-0380, USA
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8
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Pluripotency maintenance mechanism of embryonic stem cells and reprogramming. Int J Hematol 2010; 91:360-72. [DOI: 10.1007/s12185-010-0517-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2009] [Accepted: 11/12/2009] [Indexed: 11/25/2022]
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Syed M, Fenoglio-Preiser C, Skau KA, Weber GF. Acetylcholinesterase supports anchorage independence in colon cancer. Clin Exp Metastasis 2008; 25:787-98. [PMID: 18612832 DOI: 10.1007/s10585-008-9192-0] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2007] [Accepted: 06/19/2008] [Indexed: 11/24/2022]
Abstract
Various roles have been attributed to Acetylcholinesterase (AChE) in cancer. Evidence exists for a pro-apoptotic function, consistent with a protective role of AChE. Because other reports suggested that upregulated AChE in some tumors may control cell adhesion, we tested the effects of AChE on anchorage independence (an essential component of metastasis) of colon tumor cells. Several AChE inhibitors dose-dependently suppressed colony formation of HTB-38 cells in soft agar. This effect of AChE was confirmed with HTB-38 cells stably overexpressing AChE. In contrast, cell proliferation was not altered by the effective doses of these chemical inhibitors or by transfected AChE. Protection from cell cycle arrest consecutive to cancer cell detachment may be conveyed by changes in cell-matrix interactions. Reflective of such changes, the AChE overexpressing cells adhered more strongly to Fibronectin than did the vector controls. The AChE-dependent adhesion was RGD-dependent and accompanied by increased c-Myb DNA-binding, suggesting that AChE upregulates an Integrin receptor via c-Myb. In support of these observations, we find AChE message and protein to be expressed in a large fraction of colon cancers and in all colon tumor cell lines analyzed, but only rarely in normal colon specimens. Our results imply a dual role for AChE in colon cancer. While the anti-apoptotic effects of AChE may be protective against early stages of tumorigenesis, this gene product may support the later stages of transformation by enhancing anchorage independent growth. The induction of Integrins could render the cells independent of microenvironmental cues and override cell cycle arrest after deadhesion.
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Affiliation(s)
- Moyeenuddin Syed
- College of Pharmacy, University of Cincinnati Academic Health Center, 3225 Eden Avenue, Cincinnati, OH 45267-0004, USA
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10
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Tarasov KV, Tarasova YS, Tam WL, Riordon DR, Elliott ST, Kania G, Li J, Yamanaka S, Crider DG, Testa G, Li RA, Lim B, Stewart CL, Liu Y, Van Eyk JE, Wersto RP, Wobus AM, Boheler KR. B-MYB is essential for normal cell cycle progression and chromosomal stability of embryonic stem cells. PLoS One 2008; 3:e2478. [PMID: 18575582 PMCID: PMC2423619 DOI: 10.1371/journal.pone.0002478] [Citation(s) in RCA: 82] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2007] [Accepted: 05/19/2008] [Indexed: 01/11/2023] Open
Abstract
Background The transcription factor B-Myb is present in all proliferating cells, and in mice engineered to remove this gene, embryos die in utero just after implantation due to inner cell mass defects. This lethal phenotype has generally been attributed to a proliferation defect in the cell cycle phase of G1. Methodology/Principal Findings In the present study, we show that the major cell cycle defect in murine embryonic stem (mES) cells occurs in G2/M. Specifically, knockdown of B-Myb by short-hairpin RNAs results in delayed transit through G2/M, severe mitotic spindle and centrosome defects, and in polyploidy. Moreover, many euploid mES cells that are transiently deficient in B-Myb become aneuploid and can no longer be considered viable. Knockdown of B-Myb in mES cells also decreases Oct4 RNA and protein abundance, while over-expression of B-MYB modestly up-regulates pou5f1 gene expression. The coordinated changes in B-Myb and Oct4 expression are due, at least partly, to the ability of B-Myb to directly modulate pou5f1 gene promoter activity in vitro. Ultimately, the loss of B-Myb and associated loss of Oct4 lead to an increase in early markers of differentiation prior to the activation of caspase-mediated programmed cell death. Conclusions/Significance Appropriate B-Myb expression is critical to the maintenance of chromosomally stable and pluripotent ES cells, but its absence promotes chromosomal instability that results in either aneuploidy or differentiation-associated cell death.
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Affiliation(s)
- Kirill V. Tarasov
- Laboratory of Cardiovascular Science, National Institute on Aging, National Institutes of Health, Baltimore, Maryland, United States of America
| | - Yelena S. Tarasova
- Laboratory of Cardiovascular Science, National Institute on Aging, National Institutes of Health, Baltimore, Maryland, United States of America
| | - Wai Leong Tam
- Stem Cell and Developmental Biology, Genome Institute of Singapore, Singapore, Singapore
| | - Daniel R. Riordon
- Laboratory of Cardiovascular Science, National Institute on Aging, National Institutes of Health, Baltimore, Maryland, United States of America
| | - Steven T. Elliott
- Department of Medicine, Johns Hopkins University, Baltimore, Maryland, United States of America
| | - Gabriela Kania
- In vitro Differentiation Group, Leibniz Institute of Plant Genetics and Crop Plant Research, Gatersleben, Germany
| | - Jinliang Li
- Laboratory of Cardiovascular Science, National Institute on Aging, National Institutes of Health, Baltimore, Maryland, United States of America
| | - Satoshi Yamanaka
- Laboratory of Cardiovascular Science, National Institute on Aging, National Institutes of Health, Baltimore, Maryland, United States of America
| | - David G. Crider
- Laboratory of Cardiovascular Science, National Institute on Aging, National Institutes of Health, Baltimore, Maryland, United States of America
| | - Gianluca Testa
- Laboratory of Cardiovascular Science, National Institute on Aging, National Institutes of Health, Baltimore, Maryland, United States of America
| | - Ronald A. Li
- Laboratory of Stem Cell Engineering & Bioelectricity, Stem Cell Institute, University of California Davis, Davis, California, United States of America
| | - Bing Lim
- Stem Cell and Developmental Biology, Genome Institute of Singapore, Singapore, Singapore
- Harvard Institutes of Medicine, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Colin L. Stewart
- Cancer and Developmental Biology Laboratory, National Cancer Institute, Frederick, Maryland, United States of America
| | - Yie Liu
- Laboratory of Molecular Genetics, National Institute on Aging, National Institutes of Health, Baltimore, Maryland, United States of America
| | - Jennifer E. Van Eyk
- Department of Medicine, Johns Hopkins University, Baltimore, Maryland, United States of America
| | - Robert P. Wersto
- Flow Cytometry Group, National Institute on Aging, National Institutes of Health, Baltimore, Maryland, United States of America
| | - Anna M. Wobus
- In vitro Differentiation Group, Leibniz Institute of Plant Genetics and Crop Plant Research, Gatersleben, Germany
| | - Kenneth R. Boheler
- Laboratory of Cardiovascular Science, National Institute on Aging, National Institutes of Health, Baltimore, Maryland, United States of America
- * E-mail:
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11
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Sharov AA, Masui S, Sharova LV, Piao Y, Aiba K, Matoba R, Xin L, Niwa H, Ko MSH. Identification of Pou5f1, Sox2, and Nanog downstream target genes with statistical confidence by applying a novel algorithm to time course microarray and genome-wide chromatin immunoprecipitation data. BMC Genomics 2008; 9:269. [PMID: 18522731 PMCID: PMC2424064 DOI: 10.1186/1471-2164-9-269] [Citation(s) in RCA: 126] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2007] [Accepted: 06/03/2008] [Indexed: 12/15/2022] Open
Abstract
Background Target genes of a transcription factor (TF) Pou5f1 (Oct3/4 or Oct4), which is essential for pluripotency maintenance and self-renewal of embryonic stem (ES) cells, have previously been identified based on their response to Pou5f1 manipulation and occurrence of Chromatin-immunoprecipitation (ChIP)-binding sites in promoters. However, many responding genes with binding sites may not be direct targets because response may be mediated by other genes and ChIP-binding site may not be functional in terms of transcription regulation. Results To reduce the number of false positives, we propose to separate responding genes into groups according to direction, magnitude, and time of response, and to apply the false discovery rate (FDR) criterion to each group individually. Using this novel algorithm with stringent statistical criteria (FDR < 0.2) to a compendium of published and new microarray data (3, 6, 12, and 24 hr after Pou5f1 suppression) and published ChIP data, we identified 420 tentative target genes (TTGs) for Pou5f1. The majority of TTGs (372) were down-regulated after Pou5f1 suppression, indicating that the Pou5f1 functions as an activator of gene expression when it binds to promoters. Interestingly, many activated genes are potent suppressors of transcription, which include polycomb genes, zinc finger TFs, chromatin remodeling factors, and suppressors of signaling. Similar analysis showed that Sox2 and Nanog also function mostly as transcription activators in cooperation with Pou5f1. Conclusion We have identified the most reliable sets of direct target genes for key pluripotency genes – Pou5f1, Sox2, and Nanog, and found that they predominantly function as activators of downstream gene expression. Thus, most genes related to cell differentiation are suppressed indirectly.
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Affiliation(s)
- Alexei A Sharov
- Developmental Genomics and Aging Section, Laboratory of Genetics, National Institute on Aging, NIH, Baltimore, MD 21224, USA.
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12
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Tarasov KV, Testa G, Tarasova YS, Kania G, Riordon DR, Volkova M, Anisimov SV, Wobus AM, Boheler KR. Linkage of pluripotent stem cell-associated transcripts to regulatory gene networks. Cells Tissues Organs 2008; 188:31-45. [PMID: 18303244 DOI: 10.1159/000118787] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
Knowledge of the transcriptional circuitry responsible for pluripotentiality and self-renewal in embryonic stem cells is tantamount to understanding early mammalian development and a prerequisite to determining their therapeutic potential. Various techniques have employed genomics to identify transcripts that were abundant in stem cells, in an attempt to define the molecular basis of 'stemness'. In this study, we have extended traditional genomic analyses to identify cis-elements that might be implicated in the control of embryonic stem cell-restricted gene promoters. The strategy relied on the generation of a problem-specific list from serial analysis of gene expression profiles and subsequent promoter analyses to identify frameworks of multiple cis-elements conserved in space and orientation among genes from the problem-specific list. Subsequent experimental data suggest that 2 novel transcription factors, B-Myb and Maz, predicted from these models, are implicated either in the maintenance of the undifferentiated stem cell state or in early steps of differentiation.
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Affiliation(s)
- Kirill V Tarasov
- Laboratory of Cardiovascular Science, National Institute on Aging, National Institutes of Health, Baltimore, MD 21224, USA
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Ogawa K, Saito A, Matsui H, Suzuki H, Ohtsuka S, Shimosato D, Morishita Y, Watabe T, Niwa H, Miyazono K. Activin-Nodal signaling is involved in propagation of mouse embryonic stem cells. J Cell Sci 2007; 120:55-65. [PMID: 17182901 DOI: 10.1242/jcs.03296] [Citation(s) in RCA: 140] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
Embryonic stem (ES) cells are self-renewing cells that maintain pluripotency to differentiate into all types of cells. Because of their potential to provide a variety of tissues for use in regenerative medicine, there is great interest in the identification of growth factors that govern these unique properties of ES cells. However, the signaling pathways controlling ES cell proliferation remain largely unknown. Since transforming growth factor beta (TGFbeta) superfamily members have been implicated in the processes of early embryogenesis, we investigated their roles in ES cell self-renewal. Inhibition of activin-Nodal-TGFbeta signaling by Smad7 or SB-431542 dramatically decreased ES cell proliferation without decreasing ES pluripotency. By contrast, inhibition of bone morphogenetic protein (BMP) signaling by Smad6 did not exhibit such effects, suggesting that activin-Nodal-TGFbeta signaling, but not BMP signaling, is indispensable for ES cell propagation. In serum-free culture, supplementation of recombinant activin or Nodal, but not TGFbeta or BMP, significantly enhanced ES cell propagation without affecting pluripotency. We also found that activin-Nodal signaling was constitutively activated in an autocrine fashion in serum-free cultured ES cells, and that inhibition of such endogenous signaling by SB-431542 decreased ES cell propagation in serum-free conditions. These findings suggest that endogenously activated autocrine loops of activin-Nodal signaling promote ES cell self-renewal.
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Affiliation(s)
- Kazuya Ogawa
- Laboratory for Pluripotent Cell Studies, RIKEN Center for Developmental Biology, 2-2-3 Minatojima-Minamimachi, Chuo-ku, Kobe 650-0047, Japan
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14
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Guo YL, Yang B. Altered cell adhesion and cell viability in a p38alpha mitogen-activated protein kinase-deficient mouse embryonic stem cell line. Stem Cells Dev 2007; 15:655-64. [PMID: 17105401 DOI: 10.1089/scd.2006.15.655] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
p38 mitogen-activated protein (MAP) kinase alpha (p38alpha) is a broadly expressed protein kinase that regulates growth and development. Most studies of p38alpha have been in somatic cells. Little is known about its function in embryonic stem (ES) cells. Using a ES cell line isolated from p38alpha knockout mouse embryos (p38alpha (-/-) ES cells), we investigated roles of p38alpha in the regulation of ES cell activities. p38alpha (-/-) ES cells displayed several altered features different from wild-type cells. The major findings are that p38alpha (-/-) ES cells have significantly increased cell adhesion to several extracelluar matrix proteins, correlating with elevated phosphorylation of focal adhesion kinase and paxillin. p38alpha (-/-) ES cells also showed increased cell viability, correlating with increased expression of survivin and activation of AKT (protein kinase B), two molecules that are known to improve cell viability. p38alpha (-/-) ES cells reach confluence faster than wild-type cells in routine cell culture. However, this is not due to a higher cell proliferation rate in p38alpha (-/-) ES cells, but rather is likely a result of improved cell adhesion and/or cell viability. Together our results indicated that p38alpha may negatively regulate mouse ES cell adhesion and viability.
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Affiliation(s)
- Yan-Lin Guo
- Department of Biological Sciences, The University of Southern Mississippi, Hattiesburg, MS 39406, USA
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15
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Abstract
Mouse embryonic stem (ES) cells are pluripotent, as they have the ability to differentiate into the various cell types of a vertebrate embryo. Pluripotency is a property of the inner cell mass (ICM), from which mouse ES cells are derived, and of the epiblast of the blastocyst. Recent extensive molecular studies of mouse ES cells have revealed the unique molecular mechanisms that govern pluripotency. These studies show that ES cells continue to self-renew because of a self-organizing network of transcription factors that prevents their differentiation and promotes their proliferation, and because of epigenetic processes that might be under the control of the pluripotent transcription factor network.
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Affiliation(s)
- Hitoshi Niwa
- RIKEN Center for Developmental Biology (CDB Laboratory for Development and Regenerative Medicine, Kobe University Graduate School of Medicine, 7-5-1 Kusunokicho, Chuo-ku, Kobe, Hyogo 6500017, Japan.
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16
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Abstract
B-Myb is an essential transcription factor involved in control of the cell cycle and the regulation of tissue-specific gene expression in a wide range of cell types. Loss of both alleles results in early embryonic lethality at E4.5-6.5. To address the function of B-Myb in later stages of embryogenesis and in specific adult tissues, a floxed B-myb allele (B-mybF) was generated. Cre-mediated deletion in vivo was demonstrated by breeding with a transgenic GATA-Cre mouse line. An intermediate allele produced in the creation of the floxed allele, in which the PGK-neo(R) cassette is present in intron 3 (B-myb(loxneo)), was deduced to be a weak hypomorph based on the later embryonic death of homozygotes compared to B-myb(-/-) embryos. To demonstrate the efficiency and possible consequences of B-myb inactivation, we performed conditional deletion in cultured MEFs and observed decreased growth that correlated with aberrant nuclear DNA replication.
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Affiliation(s)
- Paloma García
- Institute for Biomedical Research, Birmingham University Medical School, Edgbaston, United Kingdom
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17
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Nakano I, Paucar AA, Bajpai R, Dougherty JD, Zewail A, Kelly TK, Kim KJ, Ou J, Groszer M, Imura T, Freije WA, Nelson SF, Sofroniew MV, Wu H, Liu X, Terskikh AV, Geschwind DH, Kornblum HI. Maternal embryonic leucine zipper kinase (MELK) regulates multipotent neural progenitor proliferation. ACTA ACUST UNITED AC 2005; 170:413-27. [PMID: 16061694 PMCID: PMC2171475 DOI: 10.1083/jcb.200412115] [Citation(s) in RCA: 119] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Maternal embryonic leucine zipper kinase (MELK) was previously identified in a screen for genes enriched in neural progenitors. Here, we demonstrate expression of MELK by progenitors in developing and adult brain and that MELK serves as a marker for self-renewing multipotent neural progenitors (MNPs) in cultures derived from the developing forebrain and in transgenic mice. Overexpression of MELK enhances (whereas knockdown diminishes) the ability to generate neurospheres from MNPs, indicating a function in self-renewal. MELK down-regulation disrupts the production of neurogenic MNP from glial fibrillary acidic protein (GFAP)–positive progenitors in vitro. MELK expression in MNP is cell cycle regulated and inhibition of MELK expression down-regulates the expression of B-myb, which is shown to also mediate MNP proliferation. These findings indicate that MELK is necessary for proliferation of embryonic and postnatal MNP and suggest that it regulates the transition from GFAP-expressing progenitors to rapid amplifying progenitors in the postnatal brain.
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Affiliation(s)
- Ichiro Nakano
- Department of Pharmacology, David Geffen School of Medicine at the University of California, Los Angeles, Los Angeles, CA 90095, USA
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18
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Miyazaki S, Yamato E, Miyazaki JI. Regulated expression of pdx-1 promotes in vitro differentiation of insulin-producing cells from embryonic stem cells. Diabetes 2004; 53:1030-7. [PMID: 15047618 DOI: 10.2337/diabetes.53.4.1030] [Citation(s) in RCA: 201] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Embryonic stem (ES) cells can differentiate into many cell types. Recent reports have shown that ES cells can differentiate into insulin-producing cells. However, the differentiation is not efficient enough to produce insulin-secreting cells for future therapeutic use. Pdx-1, a homeodomain-containing transcription factor, is a crucial regulator for pancreatic development. We established an ES cell line in which exogenous pdx-1 expression was precisely regulated by the Tet-off system integrated into the ROSA26 locus. Using this cell line, we examined the effect of pdx-1 expression during in vitro differentiation via embryoid body formation. The results showed that pdx-1 expression clearly enhanced the expression of the insulin 2, somatostatin, Kir6.2, glucokinase, neurogenin3, p48, Pax6, PC2, and HNF6 genes in the resulting differentiated cells. Immunohistochemical examination also revealed that insulin was highly produced in most of the differentiated ES cells. Thus, exogenous expression of pdx-1 should provide a promising approach for efficiently producing insulin-secreting cells from human ES cells for future therapeutic use in diabetic patients.
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Affiliation(s)
- Satsuki Miyazaki
- Division of Stem Cell Regulation Research, Osaka University Graduate School of Medicine, Suita, Japan
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19
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Long EM, Long MA, Tsirigotis M, Gray DA. Stimulation of the murine Uchl1 gene promoter by the B-Myb transcription factor. Lung Cancer 2004; 42:9-21. [PMID: 14512183 DOI: 10.1016/s0169-5002(03)00279-4] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
It has been reported that human lung cancers frequently overexpress both the ubiquitous cell cycle transcription factor B-myb and the ubiquitin carboxyterminal hydrolase UCHL1, an enzyme whose expression is normally limited to neurons and neuroendocrine cells in the lung. A possible explanation for the co-expression of these markers is that Uchl1 is subject to transcriptional regulation by B-Myb, and in tumors the ectopic expression of UCHL1 is a direct consequence of B-Myb overexpression. We have tested this hypothesis in the mouse model system by cloning the murine Uchl1 promoter and analyzing its regulation by murine B-Myb. Expression of a luciferase reporter gene driven by the Uchl1 promoter was induced by cotransfected B-Myb, but induction was not dependent on the presence of a myb consensus binding site identified in the promoter region. B-Myb induction was dependent on the context of the Uchl1 TATA box, as has been reported for other genes. Transgenic mice expressing a truncated, constitutively active form of B-Myb in the lung epithelium showed elevated expression of UCHL1 protein. We conclude that B-Myb can stimulate expression of the Uchl1 both in cultured cells and in vivo.
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Affiliation(s)
- Elizabeth M Long
- Ottawa Regional Cancer Center, 503 Smyth Rd., Ottawa, Ont., Canada K1H 1C4
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20
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Prindull G, Zipori D. Environmental guidance of normal and tumor cell plasticity: epithelial mesenchymal transitions as a paradigm. Blood 2004; 103:2892-9. [PMID: 15070660 DOI: 10.1182/blood-2003-08-2807] [Citation(s) in RCA: 112] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Epithelial mesenchymal transitions are a remarkable example of cellular plasticity. These transitions are the hallmark of embryo development, are pivotal in cancer progression, and seem to occur infrequently in adult organisms. The reduced incidence of transitions in the adult could result from restrictive functions of the microenvironment that stabilizes adult cell phenotypes and prevents plastic behavior. Multipotential progenitor cells exhibiting a mesenchymal phenotype have been derived from various adult tissues. The ability of these cells to differentiate into all germ layer cell types, raises the question as to whether mesenchymal epithelial transitions occur in the adult organism more frequently than presently appreciated. A series of cytokines are known to promote the transitions between epithelium and mesenchyme. Moreover, several transcription factors and other intracellular regulator molecules have been conclusively shown to mediate these transitions. However, the exact molecular basis of these transitions is yet to be resolved. The identification of the restrictive mechanisms that prevent cellular transitions in adult organisms, which seem to be unleashed in cancerous tissues, may lead to the development of tools for therapeutic tissue repair and effective tumor suppression.
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Affiliation(s)
- Gregor Prindull
- Department of Molecular Cell Biology, Weizmann Institute of Science, Rehovot, , Israel
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Joaquin M, Watson RJ. The cell cycle-regulated B-Myb transcription factor overcomes cyclin-dependent kinase inhibitory activity of p57(KIP2) by interacting with its cyclin-binding domain. J Biol Chem 2003; 278:44255-64. [PMID: 12947099 DOI: 10.1074/jbc.m308953200] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The cell cycle-regulated B-Myb transcription factor is required for early embryonic development and is implicated in regulating cell growth and differentiation. In addition to its transcriptional regulatory properties, recent data indicate that B-Myb can release active cyclin/Cdk2 activity from the retinoblastoma-related p107 protein by directly interacting with the p107 N terminus. As this p107 domain has homology to the cyclin-binding domains of the p21(Waf1/Cip1) family of cyclin-dependent kinase inhibitors (CKIs), we investigated in this study whether B-Myb could also interact with these CKIs. No in vivo interaction was found with either p21(Waf1/Cip1) or p27(KIP1), however, binding to p57(KIP2) was readily detectable in both in vivo and in vitro assays. The B-Myb-interacting region of p57(KIP2) mapped to the cyclin-binding domain. Consistent with this, B-Myb competed with cyclin A2 for binding to p57(KIP2), resulting in release of active cyclin/Cdk2 kinase. Moreover, B-Myb partially overcame the ability of p57(KIP2) to induce G1 arrest in Saos-2 cells. Despite similarities with previous p107 studies, the B-Myb domains required for interaction with p57(KIP2) were quite different from those implicated for p107. Thus, it is evident that B-Myb may promote cell proliferation by a non-transcriptional mechanism that involves release of active cyclin/Cdk2 from p57(KIP2) as well as p107.
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Affiliation(s)
- Manel Joaquin
- Ludwig Institute for Cancer Research and Department of Virology, Faculty of Medicine, Imperial College London, Norfolk Place, London W2 1PG, United Kingdom
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22
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Petrovas C, Jeay S, Lewis RE, Sonenshein GE. B-Myb repressor function is regulated by cyclin A phosphorylation and sequences within the C-terminal domain. Oncogene 2003; 22:2011-20. [PMID: 12673206 DOI: 10.1038/sj.onc.1206231] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
B-Myb is a widely expressed member of the myb oncogene family that has been shown to act as either an activator or repressor of gene transcription in a cell-type-specific fashion. For example, in aortic smooth muscle cells B-Myb represses transcription of the alpha2(V) collagen gene. Recently, phosphorylation of B-Myb by cyclin A was shown to enhance greatly its ability to transactivate. Here, we have tested the effects of cyclin A on the ability of B-Myb to repress. We report that coexpression of cyclin A abolished repression of the alpha2(V) collagen promoter, whereas a dominant-negative cyclin-dependent kinase 2 (cdk2) enhanced repression by ectopic and endogenous B-Myb protein. Mutation of 10 of 22 putative cyclin A sites, which greatly reduces the effects of cyclin A on transactivation by B-Myb, had no effect on the ability of cyclin A to alleviate B-Myb-mediated repression of alpha2(V) collagen promoter activity. Furthermore, the stability of the mutant B-Myb protein was largely unaffected by cyclin A, although ectopic expression of cyclin A enhanced the rate of decay of wild-type B-Myb protein. Thus, the mechanisms of repression and activation appear distinct, for example, mediated by different critical phosphorylation sites or protein-protein interactions. B-Myb mutants with either deletion of aa 374-581 (B-Myb-Mut3) or C-terminal truncation beyond aa 491 (B-Myb-491) positively regulated alpha2(V) collagen promoter activity, and were not affected by cyclin A. Thus, our findings indicate that the ability of B-Myb to function as a repressor of matrix promoter activity is abolished by cyclin A, and maps the sites mediating negative regulation by B-Myb to the region between aa 491 and 582.
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Golembieski WA, Rempel SA. cDNA array analysis of SPARC-modulated changes in glioma gene expression. J Neurooncol 2002; 60:213-26. [PMID: 12510773 DOI: 10.1023/a:1021167211131] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
We have demonstrated that secreted protein acidic and rich in cysteine (SPARC) is highly expressed in human gliomas and it promotes glioma invasion and delays tumor growth in vitro and in vivo. cDNA array analyses were performed to determine whether SPARC, which interacts at the cell surface, has an impact on intracellular signaling and downstream gene expression changes, which might account for some of its effects on invasion and growth. Using a doxycycline (dox)-controlled gene expression system, two cDNA array analyses were performed using a parental U87T2 clone (-SPARC) transfected with the dox-controlled transactivator and a U87T2 parental-derived SPARC-transfected clone, A2b2 (+SPARC). Array analysis performed between the parental and the SPARC-transfected clone (-dox) identified 13 upregulated genes and 14 downregulated genes. With the exception of PAI-1 and MMP2, the identified genes are novel with respect to SPARC's mechanism of action. Array analysis performed using the SPARC-transfected clone ( +/- dox) identified 2 types of gene regulation; one reversible upon SPARC suppression, the other irreversible. Two of the SPARC-induced genes, BIGH3 (irreversible by dox) and PAI-1 (reversible by dox) were further studied in additional SPARC-transfected clones, human astrocytoma tissues, and human glioma cell lines by RT-PCR and Northern blot analyses. The results indicate that: (1) the array results were validated, (2) the dox regulation was validated, and (3) the differential expression identified by the array analyses was present between normal brain and in human astrocytoma tissues and cell lines. Therefore, we conclude that these cDNA array analyses provide candidate genes involved in SPARC-mediated effects on glioma cell cycle progression, signaling, and migration, and that SPARC may induce reversible and irreversible gene expression changes. Further investigation of these candidates may shed insights into SPARC's role in glioma cell proliferation and invasion, and potential use as a therapeutic target.
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Affiliation(s)
- William A Golembieski
- Barbara Jane Levy Laboratory of Molecular Neuro-Oncology, Hermelin Brain Tumor Center, Department of Neurosurgery, Henry Ford Health Sciences Center, Detroit, MI 48202, USA
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