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Zhou Y, Nakajima R, Shirasawa M, Fikriyanti M, Zhao L, Iwanaga R, Bradford AP, Kurayoshi K, Araki K, Ohtani K. Expanding Roles of the E2F-RB-p53 Pathway in Tumor Suppression. BIOLOGY 2023; 12:1511. [PMID: 38132337 PMCID: PMC10740672 DOI: 10.3390/biology12121511] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/06/2023] [Revised: 12/03/2023] [Accepted: 12/06/2023] [Indexed: 12/23/2023]
Abstract
The transcription factor E2F links the RB pathway to the p53 pathway upon loss of function of pRB, thereby playing a pivotal role in the suppression of tumorigenesis. E2F fulfills a major role in cell proliferation by controlling a variety of growth-associated genes. The activity of E2F is controlled by the tumor suppressor pRB, which binds to E2F and actively suppresses target gene expression, thereby restraining cell proliferation. Signaling pathways originating from growth stimulative and growth suppressive signals converge on pRB (the RB pathway) to regulate E2F activity. In most cancers, the function of pRB is compromised by oncogenic mutations, and E2F activity is enhanced, thereby facilitating cell proliferation to promote tumorigenesis. Upon such events, E2F activates the Arf tumor suppressor gene, leading to activation of the tumor suppressor p53 to protect cells from tumorigenesis. ARF inactivates MDM2, which facilitates degradation of p53 through proteasome by ubiquitination (the p53 pathway). P53 suppresses tumorigenesis by inducing cellular senescence or apoptosis. Hence, in almost all cancers, the p53 pathway is also disabled. Here we will introduce the canonical functions of the RB-E2F-p53 pathway first and then the non-classical functions of each component, which may be relevant to cancer biology.
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Affiliation(s)
- Yaxuan Zhou
- Department of Biomedical Sciences, School of Biological and Environmental Sciences, Kwansei Gakuin University, 1 Gakuen Uegahara, Sanda, Hyogo 669-1330, Japan; (Y.Z.); (R.N.); (M.S.); (M.F.); (L.Z.)
| | - Rinka Nakajima
- Department of Biomedical Sciences, School of Biological and Environmental Sciences, Kwansei Gakuin University, 1 Gakuen Uegahara, Sanda, Hyogo 669-1330, Japan; (Y.Z.); (R.N.); (M.S.); (M.F.); (L.Z.)
| | - Mashiro Shirasawa
- Department of Biomedical Sciences, School of Biological and Environmental Sciences, Kwansei Gakuin University, 1 Gakuen Uegahara, Sanda, Hyogo 669-1330, Japan; (Y.Z.); (R.N.); (M.S.); (M.F.); (L.Z.)
| | - Mariana Fikriyanti
- Department of Biomedical Sciences, School of Biological and Environmental Sciences, Kwansei Gakuin University, 1 Gakuen Uegahara, Sanda, Hyogo 669-1330, Japan; (Y.Z.); (R.N.); (M.S.); (M.F.); (L.Z.)
| | - Lin Zhao
- Department of Biomedical Sciences, School of Biological and Environmental Sciences, Kwansei Gakuin University, 1 Gakuen Uegahara, Sanda, Hyogo 669-1330, Japan; (Y.Z.); (R.N.); (M.S.); (M.F.); (L.Z.)
| | - Ritsuko Iwanaga
- Department of Obstetrics and Gynecology, University of Colorado School of Medicine, Anschutz Medical Campus, 12800 East 19th Avenue, Aurora, CO 80045, USA; (R.I.); (A.P.B.)
| | - Andrew P. Bradford
- Department of Obstetrics and Gynecology, University of Colorado School of Medicine, Anschutz Medical Campus, 12800 East 19th Avenue, Aurora, CO 80045, USA; (R.I.); (A.P.B.)
| | - Kenta Kurayoshi
- Division of Molecular Genetics, Cancer Research Institute, Kanazawa University, Kakuma-machi, Kanazawa 920-1192, Japan;
| | - Keigo Araki
- Department of Morphological Biology, Ohu University School of Dentistry, 31-1 Misumido Tomitamachi, Koriyama, Fukushima 963-8611, Japan;
| | - Kiyoshi Ohtani
- Department of Biomedical Sciences, School of Biological and Environmental Sciences, Kwansei Gakuin University, 1 Gakuen Uegahara, Sanda, Hyogo 669-1330, Japan; (Y.Z.); (R.N.); (M.S.); (M.F.); (L.Z.)
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Kung CP, Weber JD. It’s Getting Complicated—A Fresh Look at p53-MDM2-ARF Triangle in Tumorigenesis and Cancer Therapy. Front Cell Dev Biol 2022; 10:818744. [PMID: 35155432 PMCID: PMC8833255 DOI: 10.3389/fcell.2022.818744] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2021] [Accepted: 01/07/2022] [Indexed: 01/31/2023] Open
Abstract
Anti-tumorigenic mechanisms mediated by the tumor suppressor p53, upon oncogenic stresses, are our bodies’ greatest weapons to battle against cancer onset and development. Consequently, factors that possess significant p53-regulating activities have been subjects of serious interest from the cancer research community. Among them, MDM2 and ARF are considered the most influential p53 regulators due to their abilities to inhibit and activate p53 functions, respectively. MDM2 inhibits p53 by promoting ubiquitination and proteasome-mediated degradation of p53, while ARF activates p53 by physically interacting with MDM2 to block its access to p53. This conventional understanding of p53-MDM2-ARF functional triangle have guided the direction of p53 research, as well as the development of p53-based therapeutic strategies for the last 30 years. Our increasing knowledge of this triangle during this time, especially through identification of p53-independent functions of MDM2 and ARF, have uncovered many under-appreciated molecular mechanisms connecting these three proteins. Through recognizing both antagonizing and synergizing relationships among them, our consideration for harnessing these relationships to develop effective cancer therapies needs an update accordingly. In this review, we will re-visit the conventional wisdom regarding p53-MDM2-ARF tumor-regulating mechanisms, highlight impactful studies contributing to the modern look of their relationships, and summarize ongoing efforts to target this pathway for effective cancer treatments. A refreshed appreciation of p53-MDM2-ARF network can bring innovative approaches to develop new generations of genetically-informed and clinically-effective cancer therapies.
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Affiliation(s)
- Che-Pei Kung
- ICCE Institute, St. Louis, MO, United States
- Division of Molecular Oncology, Department of Medicine, St. Louis, MO, United States
- *Correspondence: Che-Pei Kung, ; Jason D. Weber,
| | - Jason D. Weber
- ICCE Institute, St. Louis, MO, United States
- Division of Molecular Oncology, Department of Medicine, St. Louis, MO, United States
- Alvin J. Siteman Cancer Center, Washington University School of Medicine, St. Louis, MO, United States
- *Correspondence: Che-Pei Kung, ; Jason D. Weber,
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3
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Repenning A, Happel D, Bouchard C, Meixner M, Verel‐Yilmaz Y, Raifer H, Holembowski L, Krause E, Kremmer E, Feederle R, Keber CU, Lohoff M, Slater EP, Bartsch DK, Bauer U. PRMT1 promotes the tumor suppressor function of p14 ARF and is indicative for pancreatic cancer prognosis. EMBO J 2021; 40:e106777. [PMID: 33999432 PMCID: PMC8246066 DOI: 10.15252/embj.2020106777] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2020] [Revised: 03/31/2021] [Accepted: 04/01/2021] [Indexed: 12/04/2022] Open
Abstract
The p14ARF protein is a well-known regulator of p53-dependent and p53-independent tumor-suppressive activities. In unstressed cells, p14ARF is predominantly sequestered in the nucleoli, bound to its nucleolar interaction partner NPM. Upon genotoxic stress, p14ARF undergoes an immediate redistribution to the nucleo- and cytoplasm, where it promotes activation of cell cycle arrest and apoptosis. Here, we identify p14ARF as a novel interaction partner and substrate of PRMT1 (protein arginine methyltransferase 1). PRMT1 methylates several arginine residues in the C-terminal nuclear/nucleolar localization sequence (NLS/NoLS) of p14ARF . In the absence of cellular stress, these arginines are crucial for nucleolar localization of p14ARF . Genotoxic stress causes augmented interaction between PRMT1 and p14ARF , accompanied by arginine methylation of p14ARF . PRMT1-dependent NLS/NoLS methylation promotes the release of p14ARF from NPM and nucleolar sequestration, subsequently leading to p53-independent apoptosis. This PRMT1-p14ARF cooperation is cancer-relevant and indicative for PDAC (pancreatic ductal adenocarcinoma) prognosis and chemotherapy response of pancreatic tumor cells. Our data reveal that PRMT1-mediated arginine methylation is an important trigger for p14ARF 's stress-induced tumor-suppressive function.
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Affiliation(s)
- Antje Repenning
- Institute for Molecular Biology and Tumor Research (IMT)Philipps‐University MarburgMarburgGermany
| | - Daniela Happel
- Institute for Molecular Biology and Tumor Research (IMT)Philipps‐University MarburgMarburgGermany
| | - Caroline Bouchard
- Institute for Molecular Biology and Tumor Research (IMT)Philipps‐University MarburgMarburgGermany
| | - Marion Meixner
- Institute for Molecular Biology and Tumor Research (IMT)Philipps‐University MarburgMarburgGermany
| | - Yesim Verel‐Yilmaz
- Department of VisceralThoracic and Vascular SurgeryUniversity Hospital MarburgPhilipps‐University MarburgMarburgGermany
| | - Hartmann Raifer
- Core Facility Flow CytometryUniversity Hospital MarburgPhilipps‐University MarburgMarburgGermany
- Institute for Med. Microbiology & Hospital HygieneUniversity Hospital MarburgPhilipps‐University MarburgMarburgGermany
| | - Lena Holembowski
- Institute for Molecular Biology and Tumor Research (IMT)Philipps‐University MarburgMarburgGermany
| | | | - Elisabeth Kremmer
- Institute of Molecular ImmunologyHelmholtz Zentrum MünchenGerman Research Center for Environmental HealthMünchenGermany
| | - Regina Feederle
- Monoclonal Antibody Core FacilityInstitute for Diabetes and ObesityHelmholtz Zentrum MünchenGerman Research Center for Environmental HealthNeuherbergGermany
| | - Corinna U Keber
- Institute for PathologyUniversity Hospital MarburgPhilipps‐University MarburgMarburgGermany
| | - Michael Lohoff
- Institute for Med. Microbiology & Hospital HygieneUniversity Hospital MarburgPhilipps‐University MarburgMarburgGermany
| | - Emily P Slater
- Department of VisceralThoracic and Vascular SurgeryUniversity Hospital MarburgPhilipps‐University MarburgMarburgGermany
| | - Detlef K Bartsch
- Department of VisceralThoracic and Vascular SurgeryUniversity Hospital MarburgPhilipps‐University MarburgMarburgGermany
| | - Uta‐Maria Bauer
- Institute for Molecular Biology and Tumor Research (IMT)Philipps‐University MarburgMarburgGermany
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Abstract
The nucleolus is a prominent subnuclear compartment, where ribosome biosynthesis takes place. Recently, the nucleolus has gained attention for its novel role in the regulation of cellular stress. Nucleolar stress is emerging as a new concept, which is characterized by diverse cellular insult-induced abnormalities in nucleolar structure and function, ultimately leading to activation of p53 or other stress signaling pathways and alterations in cell behavior. Despite a number of comprehensive reviews on this concept, straightforward and clear-cut way criteria for a nucleolar stress state, regarding the factors that elicit this state, the morphological and functional alterations as well as the rationale for p53 activation are still missing. Based on literature of the past two decades, we herein summarize the evolution of the concept and provide hallmarks of nucleolar stress. Along with updated information and thorough discussion of existing confusions in the field, we pay particular attention to the current understanding of the sensing mechanisms, i.e., how stress is integrated by p53. In addition, we propose our own emphasis regarding the role of nucleolar protein NPM1 in the hallmarks of nucleolar stress and sensing mechanisms. Finally, the links of nucleolar stress to human diseases are briefly and selectively introduced.
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Affiliation(s)
- Kai Yang
- Shanghai Key Laboratory for Tumor Microenvironment and Inflammation, Department of Biochemistry and Molecular Cell Biology, Shanghai Jiao Tong University School of Medicine, 280 South Chongqing Road, Shanghai, 200025, China.,Shanghai Key Laboratory for Prevention and Treatment of Bone and Joint Diseases with Integrated Chinese-Western Medicine, Shanghai Institute of Traumatology and Orthopedics, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, 197 Ruijin 2nd Road, Shanghai, 200025, China
| | - Jie Yang
- Shanghai Key Laboratory for Tumor Microenvironment and Inflammation, Department of Biochemistry and Molecular Cell Biology, Shanghai Jiao Tong University School of Medicine, 280 South Chongqing Road, Shanghai, 200025, China
| | - Jing Yi
- Shanghai Key Laboratory for Tumor Microenvironment and Inflammation, Department of Biochemistry and Molecular Cell Biology, Shanghai Jiao Tong University School of Medicine, 280 South Chongqing Road, Shanghai, 200025, China
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5
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Yang K, Wang M, Zhao Y, Sun X, Yang Y, Li X, Zhou A, Chu H, Zhou H, Xu J, Wu M, Yang J, Yi J. A redox mechanism underlying nucleolar stress sensing by nucleophosmin. Nat Commun 2016; 7:13599. [PMID: 27886181 PMCID: PMC5133708 DOI: 10.1038/ncomms13599] [Citation(s) in RCA: 85] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2016] [Accepted: 10/18/2016] [Indexed: 12/24/2022] Open
Abstract
The nucleolus has been recently described as a stress sensor. The nucleoplasmic translocation of nucleolar protein nucleophosmin (NPM1) is a hallmark of nucleolar stress; however, the causes of this translocation and its connection to p53 activation are unclear. Using single live-cell imaging and the redox biosensors, we demonstrate that nucleolar oxidation is a general response to various cellular stresses. During nucleolar oxidation, NPM1 undergoes S-glutathionylation on cysteine 275, which triggers the dissociation of NPM1 from nucleolar nucleic acids. The C275S mutant NPM1, unable to be glutathionylated, remains in the nucleolus under nucleolar stress. Compared with wild-type NPM1 that can disrupt the p53–HDM2 interaction, the C275S mutant greatly compromises the activation of p53, highlighting that nucleoplasmic translocation of NPM1 is a prerequisite for stress-induced activation of p53. This study elucidates a redox mechanism for the nucleolar stress sensing and may help the development of therapeutic strategies. Nucleoplasmic translocation of NPM1 is integral to nucleolar stress sensing. Here, the authors show that nucleolar oxidation is a general cellular stress response, and that oxidation-related glutathionylation of NPM1 triggers its translocation and facilitates p53 activation.
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Affiliation(s)
- Kai Yang
- Shanghai Key Laboratory for Tumor Microenvironment and Inflammation, Key Laboratory of Cell Differentiation and Apoptosis of Chinese Ministry of Education, Department of Biochemistry and Molecular Cell Biology, Shanghai Jiao Tong University School of Medicine, 280 South Chongqing Road, Shanghai 200025, China
| | - Ming Wang
- Shanghai Key Laboratory for Tumor Microenvironment and Inflammation, Key Laboratory of Cell Differentiation and Apoptosis of Chinese Ministry of Education, Department of Biochemistry and Molecular Cell Biology, Shanghai Jiao Tong University School of Medicine, 280 South Chongqing Road, Shanghai 200025, China
| | - Yuzheng Zhao
- Synthetic Biology and Biotechnology Laboratory, State Key Laboratory of Bioreactor Engineering, School of Pharmacy, East China University of Science and Technology, 130 Mei Long Road, Shanghai 200237, China
| | - Xuxu Sun
- Shanghai Key Laboratory for Tumor Microenvironment and Inflammation, Key Laboratory of Cell Differentiation and Apoptosis of Chinese Ministry of Education, Department of Biochemistry and Molecular Cell Biology, Shanghai Jiao Tong University School of Medicine, 280 South Chongqing Road, Shanghai 200025, China
| | - Yi Yang
- Synthetic Biology and Biotechnology Laboratory, State Key Laboratory of Bioreactor Engineering, School of Pharmacy, East China University of Science and Technology, 130 Mei Long Road, Shanghai 200237, China
| | - Xie Li
- Synthetic Biology and Biotechnology Laboratory, State Key Laboratory of Bioreactor Engineering, School of Pharmacy, East China University of Science and Technology, 130 Mei Long Road, Shanghai 200237, China
| | - Aiwu Zhou
- Department of Pathophysiology, Shanghai Jiao Tong University School of Medicine, 280 South Chongqing Road, Shanghai 200025, China
| | - Huilin Chu
- Shanghai Key Laboratory for Tumor Microenvironment and Inflammation, Key Laboratory of Cell Differentiation and Apoptosis of Chinese Ministry of Education, Department of Biochemistry and Molecular Cell Biology, Shanghai Jiao Tong University School of Medicine, 280 South Chongqing Road, Shanghai 200025, China
| | - Hu Zhou
- Shanghai Institute of Materia Medica, 555 Zu Chong Zhi Road, Zhang Jiang Hi-Tech Park, Shanghai 201203, China
| | - Jianrong Xu
- Department of Pharmacology, Shanghai Jiao Tong University School of Medicine, 280 South Chongqing Road, Shanghai 200025, China
| | - Mian Wu
- School of Life Sciences, University of Science and Technology of China, 96 Jinzhai Road, Hefei, Anhui 230022, China
| | - Jie Yang
- Shanghai Key Laboratory for Tumor Microenvironment and Inflammation, Key Laboratory of Cell Differentiation and Apoptosis of Chinese Ministry of Education, Department of Biochemistry and Molecular Cell Biology, Shanghai Jiao Tong University School of Medicine, 280 South Chongqing Road, Shanghai 200025, China
| | - Jing Yi
- Shanghai Key Laboratory for Tumor Microenvironment and Inflammation, Key Laboratory of Cell Differentiation and Apoptosis of Chinese Ministry of Education, Department of Biochemistry and Molecular Cell Biology, Shanghai Jiao Tong University School of Medicine, 280 South Chongqing Road, Shanghai 200025, China
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6
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Hamilton G, Abraham AG, Morton J, Sampson O, Pefani DE, Khoronenkova S, Grawenda A, Papaspyropoulos A, Jamieson N, McKay C, Sansom O, Dianov GL, O'Neill E. AKT regulates NPM dependent ARF localization and p53mut stability in tumors. Oncotarget 2014; 5:6142-67. [PMID: 25071014 PMCID: PMC4171619 DOI: 10.18632/oncotarget.2178] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2014] [Accepted: 07/07/2014] [Indexed: 12/31/2022] Open
Abstract
Nucleophosmin (NPM) is known to regulate ARF subcellular localization and MDM2 activity in response to oncogenic stress, though the precise mechanism has remained elusive. Here we describe how NPM and ARF associate in the nucleoplasm to form a MDM2 inhibitory complex. We find that oligomerization of NPM drives nucleolar accumulation of ARF. Moreover, the formation of NPM and ARF oligomers antagonizes MDM2 association with the inhibitory complex, leading to activation of MDM2 E3-ligase activity and targeting of p53. We find that AKT phosphorylation of NPM-Ser48 prevents oligomerization that results in nucleoplasmic localization of ARF, constitutive MDM2 inhibition and stabilization of p53. We also show that ARF promotes p53 mutant stability in tumors and suppresses p73 mediated p21 expression and senescence. We demonstrate that AKT and PI3K inhibitors may be effective in treatment of therapeutically resistant tumors with elevated AKT and carrying gain of function mutations in p53. Our results show that the clinical candidate AKT inhibitor MK-2206 promotes ARF nucleolar localization, reduced p53(mut) stability and increased sensitivity to ionizing radiation in a xenograft model of pancreatic cancer. Analysis of human tumors indicates that phospho-S48-NPM may be a useful biomarker for monitoring AKT activity and in vivo efficacy of AKT inhibitor treatment. Critically, we propose that combination therapy involving PI3K-AKT inhibitors would benefit from a patient stratification rationale based on ARF and p53(mut) status.
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Affiliation(s)
- Garth Hamilton
- Cancer Research UK/MRC Oxford Institute, Department of Oncology, University of Oxford, Old Road Campus, Roosevelt Drive, UK; These authors contributed equally to this work
| | - Aswin G Abraham
- Cancer Research UK/MRC Oxford Institute, Department of Oncology, University of Oxford, Old Road Campus, Roosevelt Drive, UK; These authors contributed equally to this work
| | - Jennifer Morton
- Beatson Institute for Cancer Research, Garscube Estate, Switchback Road, Glasgow, UK
| | - Oliver Sampson
- Cancer Research UK/MRC Oxford Institute, Department of Oncology, University of Oxford, Old Road Campus, Roosevelt Drive, UK
| | - Dafni E Pefani
- Cancer Research UK/MRC Oxford Institute, Department of Oncology, University of Oxford, Old Road Campus, Roosevelt Drive, UK
| | - Svetlana Khoronenkova
- Cancer Research UK/MRC Oxford Institute, Department of Oncology, University of Oxford, Old Road Campus, Roosevelt Drive, UK
| | - Anna Grawenda
- Cancer Research UK/MRC Oxford Institute, Department of Oncology, University of Oxford, Old Road Campus, Roosevelt Drive, UK
| | - Angelos Papaspyropoulos
- Cancer Research UK/MRC Oxford Institute, Department of Oncology, University of Oxford, Old Road Campus, Roosevelt Drive, UK
| | - Nigel Jamieson
- West of Scotland Pancreatic Unit and University Department of Surgery, Glasgow Royal Infirmary, Alexandra Parade. Glasgow
| | - Colin McKay
- West of Scotland Pancreatic Unit and University Department of Surgery, Glasgow Royal Infirmary, Alexandra Parade. Glasgow
| | - Owen Sansom
- Beatson Institute for Cancer Research, Garscube Estate, Switchback Road, Glasgow, UK
| | - Grigory L Dianov
- Cancer Research UK/MRC Oxford Institute, Department of Oncology, University of Oxford, Old Road Campus, Roosevelt Drive, UK
| | - Eric O'Neill
- Cancer Research UK/MRC Oxford Institute, Department of Oncology, University of Oxford, Old Road Campus, Roosevelt Drive, UK
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7
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Oyanagi M, Kaneko K, Kaneko Y, Sasaki M, Nishida C, Matsuda Y, Mitsui T. Proteomic analysis of Nipponia nippon (ID#162). Anim Sci J 2014; 85:814-32. [PMID: 24961376 DOI: 10.1111/asj.12214] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2013] [Accepted: 01/28/2014] [Indexed: 11/28/2022]
Abstract
We investigated the proteome of a female Crested Ibis (Nipponia nippon, ID#162) that died on March 10, 2010 at the Sado Japanese Crested Ibis Conservation Center. Protein preparations from the brain, trachea, liver, heart, lung, proventriculus, muscular stomach, small intestine, duodenum, ovary and neck muscle were subjected to in-solution shotgun mass spectrometry (MS)/MS analyses using an LTQ Orbitrap XL mass spectrometer. A search of the National Center for Biotechnology Information Gallus gallus databases revealed 4253 GI (GenInfo Identifier) numbers with the sum of the same 11 tissues examined in the Crested Ibis. To interpret the obtained proteomics data, it was verified in detail with the data obtained from the brain of the Crested Ibis. It has been reported that drebrin A is specifically expressed in adult chicken brain. In the shotgun proteomic analyses of the Crested Ibis, we identified drebrin A as a brain-specific protein. Furthermore, Western blotting analysis of the protein preparations from 10 tissues of the Crested Ibis and 150-day-old hens using anti-drebrin antibodies showed intensive expression of approximately 110 kDa polypeptides of drebrin in both brains. We believe firmly that the present data will contribute to initial and fundamental steps toward understanding the Crested Ibis proteome.
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Affiliation(s)
- Mitsuru Oyanagi
- Genome Research Center, Faculty of Agriculture, Niigata University, Niigata, Japan; Graduate School of Science and Technology, Niigata University, Niigata, Japan; Center for Toki and Ecological Restoration, Niigata University, Niigata, Japan
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8
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Hu W, Feng Z, Levine AJ. The Regulation of Multiple p53 Stress Responses is Mediated through MDM2. Genes Cancer 2012; 3:199-208. [PMID: 23150753 DOI: 10.1177/1947601912454734] [Citation(s) in RCA: 108] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
The MDM2 oncogene is a key negative regulator of the p53 tumor suppressor protein. MDM2 and p53 form an autoregulatory feedback loop to tightly control the proper cellular responses to various stress signals in order to prevent mutations and tumor formation. The levels and function of the MDM2 protein, an E3 ubiquitin ligase, are regulated by a wide variety of extracellular and intracellular stress signals through distinct signaling pathways and mechanisms. These signals regulate the E3 ubiquitin ligase activity of MDM2, the ability of MDM2 to interact with p53 and a number of other proteins, and the cellular localization of MDM2, which in turn impact significantly upon p53 function. This review provides an overview of the regulation of MDM2 activities by the signals and factors that regulate the MDM2 protein, including genotoxic stress signals, oncogenic activation, cell cycle transition, ribosomal stress, chronic stress, neurohormones, and microRNAs. Disruption of the proper regulation of the MDM2-p53 negative feedback loop impacts significantly upon the frequency of tumorigenesis in a host. A better understanding of the complex regulation of MDM2 and its impact upon p53 function in cells under different conditions will help to develop novel and more effective strategies for cancer therapy and prevention.
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Affiliation(s)
- Wenwei Hu
- Cancer Institute of New Jersey, University of Medicine and Dentistry of New Jersey, New Brunswick, NJ, USA
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9
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Hepatocyte odd protein shuttling (HOPS) is a bridging protein in the nucleophosmin-p19 Arf network. Oncogene 2012; 32:3350-8. [PMID: 22890319 DOI: 10.1038/onc.2012.353] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2012] [Revised: 06/26/2012] [Accepted: 06/30/2012] [Indexed: 01/03/2023]
Abstract
Nucleophosmin (NPM), a ubiquitously and abundantly expressed protein, occurs in the nucleolus, shuttling between the nucleoplasm and cytoplasm. The NPM gene is mutated in almost 30% of human acute myeloid leukemia cells. NPM interacts with p53 and p19(Arf), directs localization of p19(Arf) in the nucleolus and protects the latter from degradation. Hepatocyte odd protein shuttling (HOPS) is also a ubiquitously expressed protein that moves between the nucleus and cytoplasm. Within the nucleus of resting cells, HOPS overexpression causes cell cycle arrest in G0/G1. HOPS knockdown causes centrosome hyperamplification leading to multinucleated cells and the formation of micronuclei. We demonstrate a direct interaction of HOPS with NPM and p19(Arf), resulting in a functionally active trimeric complex. NPM appeared to regulate HOPS half-life, which, in turn, stabilized p19(Arf) and controlled its localization in the nucleolus. These findings suggest that HOPS acts as a functional bridge in the interaction between NPM and p19(Arf), providing new mechanistic insight into how NPM and p19(Arf) will oppose tumor cell proliferation.
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10
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NPM1/B23: A Multifunctional Chaperone in Ribosome Biogenesis and Chromatin Remodeling. Biochem Res Int 2010; 2011:195209. [PMID: 21152184 PMCID: PMC2989734 DOI: 10.1155/2011/195209] [Citation(s) in RCA: 226] [Impact Index Per Article: 16.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2010] [Accepted: 08/29/2010] [Indexed: 12/21/2022] Open
Abstract
At a first glance, ribosome biogenesis and chromatin remodeling are quite different processes, but they share a common problem involving interactions between charged nucleic acids and small basic proteins that may result in unwanted intracellular aggregations. The multifunctional nuclear acidic chaperone NPM1 (B23/nucleophosmin) is active in several stages of ribosome biogenesis, chromatin remodeling, and mitosis as well as in DNA repair, replication and transcription. In addition, NPM1 plays an important role in the Myc-ARF-p53 pathway as well as in SUMO regulation. However, the relative importance of NPM1 in these processes remains unclear. Provided herein is an update on the expanding list of the diverse activities and interacting partners of NPM1. Mechanisms of NPM1 nuclear export functions of NPM1 in the nucleolus and at the mitotic spindle are discussed in relation to tumor development. It is argued that the suggested function of NPM1 as a histone chaperone could explain several, but not all, of the effects observed in cells following changes in NPM1 expression. A future challenge is to understand how NPM1 is activated, recruited, and controlled to carry out its functions.
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11
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Chen D, Yoon JB, Gu W. Reactivating the ARF-p53 axis in AML cells by targeting ULF. Cell Cycle 2010; 9:2946-51. [PMID: 20699639 DOI: 10.4161/cc.9.15.12355] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
The tumor suppressor ARF plays an essential role in the cellular response to oncogenic stress mainly through activation of p53. Nucleophosmin (NPM), a multifunctional protein, forms a stable protein complex with ARF in the nucleolus and protects ARF from the proteasome-mediated degradation. Notably, NPM is mutated in about one third of acute myeloid leukaemia (AML) patients and these mutations lead to aberrant cytoplasmic dislocation of nucleophosmin (NPM-c). Cytoplasmic NPM mutants lose their abilities to retain ARF in the nucleolus and fail to stabilize ARF. Thus, activation of the ARF-p53 axis is significantly compromised in these AML cells. We have recently identified the ubiquitin ligase of ARF (ULF) as a key factor that controls ARF turnover in human cells. Here, we found that the steady levels of both ARF and p53 are very low in human acute myeloid leukaemia OCI-AML3 cells expressing cytoplamsic dislocated nucleophosmin (NPM-c). As expected, ARF is very unstable and rapidly degraded by proteasome. Nevertheless, ULF knockdown stabilizes ARF and reactivates p53 responses in these AML cells. These results further demonstrate that ULF is a bona fide E3 ligase for ARF and also suggest that ULF is an important target for activating the ARF-p53 axis in human AML cells.
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Affiliation(s)
- Delin Chen
- Institute for Cancer Genetics, and Department of Pathology and Cell Biology, College of Physicians & Surgeons, Columbia University, New York, NY, USA
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12
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Hellström AR, Sundström E, Gunnarsson U, Bed’Hom B, Tixier-Boichard M, Honaker CF, Sahlqvist AS, Jensen P, Kämpe O, Siegel PB, Kerje S, Andersson L. Sex-linked barring in chickens is controlled by the CDKN2A /B tumour suppressor locus. Pigment Cell Melanoma Res 2010; 23:521-30. [DOI: 10.1111/j.1755-148x.2010.00700.x] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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13
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Chen D, Shan J, Zhu WG, Qin J, Gu W. Transcription-independent ARF regulation in oncogenic stress-mediated p53 responses. Nature 2010; 464:624-7. [PMID: 20208519 DOI: 10.1038/nature08820] [Citation(s) in RCA: 117] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2009] [Accepted: 01/07/2010] [Indexed: 11/09/2022]
Abstract
The tumour suppressor ARF is specifically required for p53 activation under oncogenic stress. Recent studies showed that p53 activation mediated by ARF, but not that induced by DNA damage, acts as a major protection against tumorigenesis in vivo under certain biological settings, suggesting that the ARF-p53 axis has more fundamental functions in tumour suppression than originally thought. Because ARF is a very stable protein in most human cell lines, it has been widely assumed that ARF induction is mediated mainly at the transcriptional level and that activation of the ARF-p53 pathway by oncogenes is a much slower and largely irreversible process by comparison with p53 activation after DNA damage. Here we report that ARF is very unstable in normal human cells but that its degradation is inhibited in cancerous cells. Through biochemical purification, we identified a specific ubiquitin ligase for ARF and named it ULF. ULF interacts with ARF both in vitro and in vivo and promotes the lysine-independent ubiquitylation and degradation of ARF. ULF knockdown stabilizes ARF in normal human cells, triggering ARF-dependent, p53-mediated growth arrest. Moreover, nucleophosmin (NPM) and c-Myc, both of which are commonly overexpressed in cancer cells, are capable of abrogating ULF-mediated ARF ubiquitylation through distinct mechanisms, and thereby promote ARF stabilization in cancer cells. These findings reveal the dynamic feature of the ARF-p53 pathway and suggest that transcription-independent mechanisms are critically involved in ARF regulation during responses to oncogenic stress.
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Affiliation(s)
- Delin Chen
- Institute for Cancer Genetics, and Department of Pathology and Cell Biology College of Physicians & Surgeons, Columbia University, 1130 St Nicholas Avenue, New York, New York 10032, USA
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Rau R, Brown P. Nucleophosmin (NPM1) mutations in adult and childhood acute myeloid leukaemia: towards definition of a new leukaemia entity. Hematol Oncol 2009; 27:171-81. [PMID: 19569254 DOI: 10.1002/hon.904] [Citation(s) in RCA: 99] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Nucleophosmin (NPM) is a ubiquitously expressed chaperone protein that shuttles rapidly between the nucleus and cytoplasm, but predominantly resides in the nucleolus. It plays key roles in ribosome biogenesis, centrosome duplication, genomic stability, cell cycle progression and apoptosis. Somatic mutations in exon 12 of the NPM gene (NPM1) are the most frequent genetic abnormality in adult acute myeloid leukaemia (AML), found in approximately 35% of all cases and up to 60% of patients with normal karyotype (NK) AML. In children, NPM1 mutations are far less frequent, occurring in 8-10% of all AML cases, and in approximately 25% of those with a NK. NPM1 mutations lead to aberrant localization of the NPM protein into the cytoplasm, thus the designation, NPMc+ AML. NPMc+ AML is seen predominantly in patients with a NK and is essentially mutually exclusive of recurrent chromosomal translocations. Patients with NPM1 mutations are twice as likely as those who lack an NPM1 mutation to also have a FMS-like tyrosine kinase (FLT3) internal tandem duplication (ITD) mutation. NPMc+ AML is also characterized by a unique gene expression signature and microRNA signature. NPMc+ AML has important prognostic significance, as NPMc+ AML, in the absence of a coexisting FLT3-ITD mutation, is associated with a favourable outcome. NPM1 mutations have also shown great stability during disease evolution, and therefore represent a possible marker for minimal residual disease detection. Given its distinctive biologic and clinical features and its clear clinical relevance, NPMc+ AML is included as a provisional entity in the 2008 WHO classifications. There is still much to be learned about this genetic alteration, including its exact role in leukaemogenesis, how it interacts with other mutations and why it confers a more favourable prognosis. Further, it represents a potential therapeutic target warranting research aimed at identifying novel small molecules with activity in NPMc+ AML.
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Affiliation(s)
- Rachel Rau
- Departments of Oncology and Pediatrics, School of Medicine, Johns Hopkins University, Baltimore, MD, USA
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Xi L, Feber A, Gupta V, Wu M, Bergemann AD, Landreneau RJ, Litle VR, Pennathur A, Luketich JD, Godfrey TE. Whole genome exon arrays identify differential expression of alternatively spliced, cancer-related genes in lung cancer. Nucleic Acids Res 2008; 36:6535-47. [PMID: 18927117 PMCID: PMC2582617 DOI: 10.1093/nar/gkn697] [Citation(s) in RCA: 89] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Alternative processing of pre-mRNA transcripts is a major source of protein diversity in eukaryotes and has been implicated in several disease processes including cancer. In this study we have performed a genome wide analysis of alternative splicing events in lung adenocarcinoma. We found that 2369 of the 17 800 core Refseq genes appear to have alternative transcripts that are differentially expressed in lung adenocarcinoma versus normal. According to their known functions the largest subset of these genes (30.8%) is believed to be cancer related. Detailed analysis was performed for several genes using PCR, quantitative RT-PCR and DNA sequencing. We found overexpression of ERG variant 2 but not variant 1 in lung tumors and overexpression of CEACAM1 variant 1 but not variant 2 in lung tumors but not in breast or colon tumors. We also identified a novel, overexpressed variant of CDH3 and verified the existence and overexpression of a novel variant of P16 transcribed from the CDKN2A locus. These findings demonstrate how analysis of alternative pre-mRNA processing can shed additional light on differences between tumors and normal tissues as well as between different tumor types. Such studies may lead to the development of additional tools for tumor diagnosis, prognosis and therapy.
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Affiliation(s)
- Liqiang Xi
- Department of Pathology, Mount Sinai School of Medicine, New York, NY 10029, USA
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