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Oncolytic HSV: Underpinnings of Tumor Susceptibility. Viruses 2021; 13:v13071408. [PMID: 34372614 PMCID: PMC8310378 DOI: 10.3390/v13071408] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2021] [Revised: 07/03/2021] [Accepted: 07/14/2021] [Indexed: 12/12/2022] Open
Abstract
Oncolytic herpes simplex virus (oHSV) is a therapeutic modality that has seen substantial success for the treatment of cancer, though much remains to be improved. Commonly attenuated through the deletion or alteration of the γ134.5 neurovirulence gene, the basis for the success of oHSV relies in part on the malignant silencing of cellular pathways critical for limiting these viruses in healthy host tissue. However, only recently have the molecular mechanisms underlying the success of these treatments begun to emerge. Further clarification of these mechanisms can strengthen rational design approaches to develop the next generation of oHSV. Herein, we review our current understanding of the molecular basis for tumor susceptibility to γ134.5-attenuated oHSV, with particular focus on the malignant suppression of nucleic acid sensing, along with strategies meant to improve the clinical efficacy of these therapeutic viruses.
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Vo DK, Engler A, Stoimenovski D, Hartig R, Kaehne T, Kalinski T, Naumann M, Haybaeck J, Nass N. Interactome Mapping of eIF3A in a Colon Cancer and an Immortalized Embryonic Cell Line Using Proximity-Dependent Biotin Identification. Cancers (Basel) 2021; 13:cancers13061293. [PMID: 33799492 PMCID: PMC7999522 DOI: 10.3390/cancers13061293] [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: 02/16/2021] [Revised: 03/08/2021] [Accepted: 03/11/2021] [Indexed: 12/12/2022] Open
Abstract
Translation initiation comprises complex interactions of eukaryotic initiation factor (eIF) subunits and the structural elements of the mRNAs. Translation initiation is a key process for building the cell's proteome. It not only determines the total amount of protein synthesized but also controls the translation efficiency for individual transcripts, which is important for cancer or ageing. Thus, understanding protein interactions during translation initiation is one key that contributes to understanding how the eIF subunit composition influences translation or other pathways not yet attributed to eIFs. We applied the BioID technique to two rapidly dividing cell lines (the immortalized embryonic cell line HEK-293T and the colon carcinoma cell line HCT-166) in order to identify interacting proteins of eIF3A, a core subunit of the eukaryotic initiation factor 3 complex. We identified a total of 84 interacting proteins, with very few proteins being specific to one cell line. When protein biosynthesis was blocked by thapsigargin-induced endoplasmic reticulum (ER) stress, the interacting proteins were considerably smaller in number. In terms of gene ontology, although eIF3A interactors are mainly part of the translation machinery, protein folding and RNA binding were also found. Cells suffering from ER-stress show a few remaining interactors which are mainly ribosomal proteins or involved in RNA-binding.
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Affiliation(s)
- Diep-Khanh Vo
- Department of Pathology, Medical Faculty, Otto-von-Guericke University Magdeburg, D-39120 Magdeburg, Germany; (D.-K.V.); (D.S.); (T.K.); (J.H.)
| | - Alexander Engler
- Institute of Experimental Internal Medicine, Medical Faculty, Otto von Guericke University, D-39120 Magdeburg, Germany; (A.E.); (T.K.); (M.N.)
| | - Darko Stoimenovski
- Department of Pathology, Medical Faculty, Otto-von-Guericke University Magdeburg, D-39120 Magdeburg, Germany; (D.-K.V.); (D.S.); (T.K.); (J.H.)
| | - Roland Hartig
- Institute of Molecular and Clinical Immunology, Otto von Guericke University Magdeburg, Leipziger Str. 44, D-39120 Magdeburg, Germany;
| | - Thilo Kaehne
- Institute of Experimental Internal Medicine, Medical Faculty, Otto von Guericke University, D-39120 Magdeburg, Germany; (A.E.); (T.K.); (M.N.)
| | - Thomas Kalinski
- Department of Pathology, Medical Faculty, Otto-von-Guericke University Magdeburg, D-39120 Magdeburg, Germany; (D.-K.V.); (D.S.); (T.K.); (J.H.)
| | - Michael Naumann
- Institute of Experimental Internal Medicine, Medical Faculty, Otto von Guericke University, D-39120 Magdeburg, Germany; (A.E.); (T.K.); (M.N.)
| | - Johannes Haybaeck
- Department of Pathology, Medical Faculty, Otto-von-Guericke University Magdeburg, D-39120 Magdeburg, Germany; (D.-K.V.); (D.S.); (T.K.); (J.H.)
- Department of Pathology, Neuropathology, and Molecular Pathology, Medical University of Innsbruck, A-6020 Innsbruck, Austria
- Department of Pathology, Diagnostic & Research Center for Molecular BioMedicine, Institute of Pathology, Medical University of Graz, A-8010 Graz, Austria
- Center for Biomarker Research in Medicine, A-8010 Graz, Austria
| | - Norbert Nass
- Department of Pathology, Medical Faculty, Otto-von-Guericke University Magdeburg, D-39120 Magdeburg, Germany; (D.-K.V.); (D.S.); (T.K.); (J.H.)
- Correspondence:
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Lee YS, Kunkeaw N, Lee YS. Protein kinase R and its cellular regulators in cancer: An active player or a surveillant? WILEY INTERDISCIPLINARY REVIEWS-RNA 2019; 11:e1558. [PMID: 31231984 DOI: 10.1002/wrna.1558] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/09/2019] [Revised: 05/24/2019] [Accepted: 05/28/2019] [Indexed: 12/12/2022]
Abstract
Protein kinase R (PKR), originally known as an antiviral protein, senses various stresses as well as pathogen-driven double-stranded RNAs. Thereby activated PKR provokes diverse downstream events, including eIF2α phosphorylation and nuclear factor kappa-light-chain-enhancer of activated B cells activation. Consequently, PKR induces apoptosis and inflammation, both of which are highly important in cancer as much as its original antiviral role. Therefore, cellular proteins and RNAs should tightly control PKR activity. PKR and its regulators are often dysregulated in cancer and it is undoubted that such dysregulation contributes to tumorigenesis. However, PKR's precise role in cancer is still in debate, due to incomprehensible and even contradictory data. In this review, we introduce important cellular PKR regulators and discuss about their roles in cancer. Among them, we pay particular attention to nc886, a PKR repressor noncoding RNA that has been identified relatively recently, because its expression pattern in cancer can explain interesting yet obscure oncologic aspects of PKR. Based on nc886 and its regulation of PKR, we have proposed a tumor surveillance model, which reconciles contradictory data about PKR in cancer. This article is categorized under: Regulatory RNAs/RNAi/Riboswitches > Regulatory RNAs RNA Interactions with Proteins and Other Molecules > Protein-RNA Interactions: Functional Implications.
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Affiliation(s)
- Yong Sun Lee
- Department of Cancer Biomedical Science, Graduate School of Cancer Science and Policy, National Cancer Center, Goyang, Korea
| | - Nawapol Kunkeaw
- Institute of Molecular Biosciences, Mahidol University, Nakhon Pathom, Thailand
| | - Yeon-Su Lee
- Division of Clinical Research, Research Institute, National Cancer Center, Goyang, Korea
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Ciribilli Y, Singh P, Inga A, Borlak J. c-Myc targeted regulators of cell metabolism in a transgenic mouse model of papillary lung adenocarcinoma. Oncotarget 2018; 7:65514-65539. [PMID: 27602772 PMCID: PMC5323172 DOI: 10.18632/oncotarget.11804] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2016] [Accepted: 08/24/2016] [Indexed: 12/31/2022] Open
Abstract
c-Myc's role in pulmonary cancer metabolism is uncertain. We therefore investigated c-Myc activity in papillary lung adenocarcinomas (PLAC). Genomics revealed 90 significantly regulated genes (> 3-fold) coding for cell growth, DNA metabolism, RNA processing and ribosomal biogenesis and bioinformatics defined c-Myc binding sites (TFBS) at > 95% of up-regulated genes. EMSA assays at 33 novel TFBS evidenced DNA binding activity and ChIP-seq data retrieved from public repositories confirmed these to be c-Myc bound. Dual-luciferase gene reporter assays developed for RNA-Terminal-Phosphate-Cyclase-Like-1(RCL1), Ribosomal-Protein-SA(RPSA), Nucleophosmin/Nucleoplasmin-3(NPM3) and Hexokinase-1(HK1) confirmed c-Myc functional relevance and ChIP assays with HEK293T cells over-expressing ectopic c-Myc demonstrated enriched c-Myc occupancy at predicted TFBS for RCL1, NPM3, HK1 and RPSA. Note, c-Myc recruitment on chromatin was comparable to the positive controls CCND2 and CDK4. Computational analyses defined master regulators (MR), i.e. heterogeneous nuclear ribonucleoprotein A1, nucleolin, the apurinic/apyrimidinic endonuclease 1, triosephosphate-isomerase 1, folate transporter (SLC19A1) and nucleophosmin to influence activity of up to 90% of PLAC-regulated genes. Their expression was induced by 3-, 3-, 6-, 3-, 11- and 7-fold, respectively. STRING analysis confirmed protein-protein-interactions of regulated genes and Western immunoblotting of fatty acid synthase, serine hydroxyl-methyltransferase 1, arginine 1 and hexokinase 2 showed tumor specific induction. Published knock down studies confirmed these proteins to induce apoptosis by disrupting neoplastic lipogenesis, by endorsing uracil accumulation and by suppressing arginine metabolism and glucose-derived ribonucleotide biosynthesis. Finally, translational research demonstrated high expression of MR and of 47 PLAC up-regulated genes to be associated with poor survival in lung adenocarcinoma patients (HR 3.2 p < 0.001) thus, providing a rationale for molecular targeted therapies in PLACs.
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Affiliation(s)
- Yari Ciribilli
- Centre for Integrative Biology (CIBIO), University of Trento, 38123 Povo (TN), Italy
| | - Prashant Singh
- Centre for Pharmacology and Toxicology, Hannover Medical School, 30625 Hannover, Germany
| | - Alberto Inga
- Centre for Integrative Biology (CIBIO), University of Trento, 38123 Povo (TN), Italy
| | - Jürgen Borlak
- Centre for Pharmacology and Toxicology, Hannover Medical School, 30625 Hannover, Germany
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Retrospective Proteomic Screening of 100 Breast Cancer Tissues. Proteomes 2017; 5:proteomes5030015. [PMID: 28686225 PMCID: PMC5620532 DOI: 10.3390/proteomes5030015] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2017] [Revised: 06/20/2017] [Accepted: 07/04/2017] [Indexed: 12/18/2022] Open
Abstract
The present investigation has been conducted on one hundred tissue fragments of breast cancer, collected and immediately cryopreserved following the surgical resection. The specimens were selected from patients with invasive ductal carcinoma of the breast, the most frequent and potentially aggressive type of mammary cancer, with the objective to increase the knowledge of breast cancer molecular markers potentially useful for clinical applications. The proteomic screening; by 2D-IPG and mass spectrometry; allowed us to identify two main classes of protein clusters: proteins expressed ubiquitously at high levels in all patients; and proteins expressed sporadically among the same patients. Within the group of ubiquitous proteins, glycolytic enzymes and proteins with anti-apoptotic activity were predominant. Among the sporadic ones, proteins involved in cell motility, molecular chaperones and proteins involved in the detoxification appeared prevalent. The data of the present study indicates that the primary tumor growth is reasonably supported by concurrent events: the inhibition of apoptosis and stimulation of cellular proliferation, and the increased expression of glycolytic enzymes with multiple functions. The second phase of the evolution of the tumor can be prematurely scheduled by the occasional presence of proteins involved in cell motility and in the defenses of the oxidative stress. We suggest that this approach on large-scale 2D-IPG proteomics of breast cancer is currently a valid tool that offers the opportunity to evaluate on the same assay the presence and recurrence of individual proteins, their isoforms and short forms, to be proposed as prognostic indicators and susceptibility to metastasis in patients operated on for invasive ductal carcinoma of the breast.
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Fung SK, Zou T, Cao B, Lee PY, Fung YME, Hu D, Lok CN, Che CM. Cyclometalated Gold(III) Complexes Containing N-Heterocyclic Carbene Ligands Engage Multiple Anti-Cancer Molecular Targets. Angew Chem Int Ed Engl 2017. [DOI: 10.1002/ange.201612583] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Affiliation(s)
- Sin Ki Fung
- State Key Laboratory of Synthetic Chemistry; Institute of Molecular Functional Materials; Chemical Biology Centre and Department of Chemistry; The University of Hong Kong; Pokfulam Road Hong Kong China
| | - Taotao Zou
- State Key Laboratory of Synthetic Chemistry; Institute of Molecular Functional Materials; Chemical Biology Centre and Department of Chemistry; The University of Hong Kong; Pokfulam Road Hong Kong China
| | - Bei Cao
- State Key Laboratory of Synthetic Chemistry; Institute of Molecular Functional Materials; Chemical Biology Centre and Department of Chemistry; The University of Hong Kong; Pokfulam Road Hong Kong China
| | - Pui-Yan Lee
- State Key Laboratory of Synthetic Chemistry; Institute of Molecular Functional Materials; Chemical Biology Centre and Department of Chemistry; The University of Hong Kong; Pokfulam Road Hong Kong China
| | - Yi Man Eva Fung
- State Key Laboratory of Synthetic Chemistry; Institute of Molecular Functional Materials; Chemical Biology Centre and Department of Chemistry; The University of Hong Kong; Pokfulam Road Hong Kong China
| | - Di Hu
- State Key Laboratory of Synthetic Chemistry; Institute of Molecular Functional Materials; Chemical Biology Centre and Department of Chemistry; The University of Hong Kong; Pokfulam Road Hong Kong China
| | - Chun-Nam Lok
- State Key Laboratory of Synthetic Chemistry; Institute of Molecular Functional Materials; Chemical Biology Centre and Department of Chemistry; The University of Hong Kong; Pokfulam Road Hong Kong China
| | - Chi-Ming Che
- State Key Laboratory of Synthetic Chemistry; Institute of Molecular Functional Materials; Chemical Biology Centre and Department of Chemistry; The University of Hong Kong; Pokfulam Road Hong Kong China
- HKU Shenzhen Institute of Research and Innovation; Shenzhen 518053 China
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Fung SK, Zou T, Cao B, Lee PY, Fung YME, Hu D, Lok CN, Che CM. Cyclometalated Gold(III) Complexes Containing N-Heterocyclic Carbene Ligands Engage Multiple Anti-Cancer Molecular Targets. Angew Chem Int Ed Engl 2017; 56:3892-3896. [PMID: 28247451 DOI: 10.1002/anie.201612583] [Citation(s) in RCA: 98] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2016] [Indexed: 01/03/2023]
Abstract
Metal N-heterocyclic carbene (NHC) complexes are a promising class of anti-cancer agents displaying potent in vitro and in vivo activities. Taking a multi-faceted approach employing two clickable photoaffinity probes, herein we report the identification of multiple molecular targets for anti-cancer active pincer gold(III) NHC complexes. These complexes display potent and selective cytotoxicity against cultured cancer cells and in vivo anti-tumor activities in mice bearing xenografts of human cervical and lung cancers. Our experiments revealed the specific engagement of the gold(III) complexes with multiple cellular targets, including HSP60, vimentin, nucleophosmin, and YB-1, accompanied by expected downstream mechanisms of action. Additionally, PtII and PdII analogues can also bind the cellular proteins targeted by the gold(III) complexes, uncovering a distinct pincer cyclometalated metal-NHC scaffold in the design of anti-cancer metal medicines with multiple molecular targets.
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Affiliation(s)
- Sin Ki Fung
- State Key Laboratory of Synthetic Chemistry, Institute of Molecular Functional Materials, Chemical Biology Centre and Department of Chemistry, The University of Hong Kong, Pokfulam Road, Hong Kong, China
| | - Taotao Zou
- State Key Laboratory of Synthetic Chemistry, Institute of Molecular Functional Materials, Chemical Biology Centre and Department of Chemistry, The University of Hong Kong, Pokfulam Road, Hong Kong, China
| | - Bei Cao
- State Key Laboratory of Synthetic Chemistry, Institute of Molecular Functional Materials, Chemical Biology Centre and Department of Chemistry, The University of Hong Kong, Pokfulam Road, Hong Kong, China
| | - Pui-Yan Lee
- State Key Laboratory of Synthetic Chemistry, Institute of Molecular Functional Materials, Chemical Biology Centre and Department of Chemistry, The University of Hong Kong, Pokfulam Road, Hong Kong, China
| | - Yi Man Eva Fung
- State Key Laboratory of Synthetic Chemistry, Institute of Molecular Functional Materials, Chemical Biology Centre and Department of Chemistry, The University of Hong Kong, Pokfulam Road, Hong Kong, China
| | - Di Hu
- State Key Laboratory of Synthetic Chemistry, Institute of Molecular Functional Materials, Chemical Biology Centre and Department of Chemistry, The University of Hong Kong, Pokfulam Road, Hong Kong, China
| | - Chun-Nam Lok
- State Key Laboratory of Synthetic Chemistry, Institute of Molecular Functional Materials, Chemical Biology Centre and Department of Chemistry, The University of Hong Kong, Pokfulam Road, Hong Kong, China
| | - Chi-Ming Che
- State Key Laboratory of Synthetic Chemistry, Institute of Molecular Functional Materials, Chemical Biology Centre and Department of Chemistry, The University of Hong Kong, Pokfulam Road, Hong Kong, China.,HKU Shenzhen Institute of Research and Innovation, Shenzhen, 518053, China
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Li S, Zhang X, Zhou Z, Huang Z, Liu L, Huang Z. Downregulation of nucleophosmin expression inhibited proliferation and induced apoptosis in salivary gland adenoid cystic carcinoma. J Oral Pathol Med 2016; 46:175-181. [PMID: 27501253 DOI: 10.1111/jop.12482] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/08/2016] [Indexed: 11/29/2022]
Abstract
BACKGROUND This study aimed to explore the relationship between nucleophosmin (NPM1) and patient clinical characteristics. Moreover, we investigated the effect of NPM1 in tumor proliferation and apoptosis of salivary gland adenoid cystic carcinoma (SACC). MATERIALS AND METHODS NPM1 expression was examined in 74 specimens of SACC and 31 non-cancerous epithelium adjacent to carcinoma (NCEAC) by immunohistochemistry (IHC). RNA interference technology was used to silence NPM1 expression in SACC cells. We used transwell culture assay, cell counting kit-8 tests, and colony formation assay to test the proliferation, cisplatin resistance, migration, and invasiveness of SACC cells. RESULTS The nuclear and cytoplasmic expression of NPM1 in SACC tissue was overexpressed and was tightly linked to perineural invasion and lymph node metastasis. The downregulation of NPM1 inhibited proliferation and induced apoptosis in SACC cells. Knockdown of NPM1 expression had no effect on chemoresistance migration, or invasiveness. CONCLUSIONS NPM1 may play an important role in tumor progress in SACC and is a potential biomarker for SACC.
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Affiliation(s)
- Shihao Li
- Guangdong Provincial Key Laboratory of Malignant Tumor Epigenetics and Gene Regulation, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou, China.,Departments of Oral and Maxillofacial Surgery, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou, China
| | - Xinyu Zhang
- Department of Oral-maxillofacial Head and Neck Surgery, Ninth People's Hospital, College of Stomatology, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Zhechong Zhou
- Department of stomatology, The First Affiliated hospital, GuangDong Pharmaceutical University, Guangzhou, China
| | - Zixian Huang
- Guangdong Provincial Key Laboratory of Malignant Tumor Epigenetics and Gene Regulation, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou, China.,Departments of Oral and Maxillofacial Surgery, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou, China
| | - Liu Liu
- Department of Oral-maxillofacial Head and Neck Surgery, Ninth People's Hospital, College of Stomatology, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Zhiquan Huang
- Guangdong Provincial Key Laboratory of Malignant Tumor Epigenetics and Gene Regulation, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou, China.,Departments of Oral and Maxillofacial Surgery, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou, China
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Marchal JA, Lopez GJ, Peran M, Comino A, Delgado JR, García-García JA, Conde V, Aranda FM, Rivas C, Esteban M, Garcia MA. The impact of PKR activation: from neurodegeneration to cancer. FASEB J 2014; 28:1965-74. [PMID: 24522206 DOI: 10.1096/fj.13-248294] [Citation(s) in RCA: 81] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
An inverse association between cancer and neurodegeneration is plausible because these biological processes share several genes and signaling pathways. Whereas uncontrolled cell proliferation and decreased apoptotic cell death governs cancer, excessive apoptosis contributes to neurodegeneration. Protein kinase R (PKR), an interferon-inducible double-stranded RNA protein kinase, is involved in both diseases. PKR activation blocks global protein synthesis through eIF2α phosphorylation, leading to cell death in response to a variety of cellular stresses. However, PKR also has the dual role of activating the nuclear factor κ-B pathway, promoting cell proliferation. Whereas PKR is recognized for its negative effects on neurodegenerative diseases, in part, inducing high level of apoptosis, the role of PKR activation in cancer remains controversial. In general, PKR is considered to have a tumor suppressor function, and some clinical data show a correlation between suppressed or inactivated PKR and a poor prognosis for several cancers. However, other studies show high PKR expression and activation levels in various cancers, suggesting that PKR might contribute to neoplastic progression. Understanding the cellular factors and signals involved in the regulation of PKR in these age-related diseases is relevant and may have important clinical implications. The present review highlights the current knowledge on the role of PKR in neurodegeneration and cancer, with special emphasis on its regulation and clinical implications.
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Affiliation(s)
- Juan A Marchal
- 1University Hospital Virgen de las Nieves, Azpitarte sn., Granada E-18012, Spain.
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Donnelly N, Gorman AM, Gupta S, Samali A. The eIF2α kinases: their structures and functions. Cell Mol Life Sci 2013; 70:3493-511. [PMID: 23354059 PMCID: PMC11113696 DOI: 10.1007/s00018-012-1252-6] [Citation(s) in RCA: 587] [Impact Index Per Article: 53.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2012] [Revised: 12/16/2012] [Accepted: 12/20/2012] [Indexed: 01/02/2023]
Abstract
Cell signaling in response to an array of diverse stress stimuli converges on the phosphorylation of the α-subunit of eukaryotic initiation factor 2 (eIF2). Phosphorylation of eIF2α on serine 51 results in a severe decline in de novo protein synthesis and is an important strategy in the cell's armory against stressful insults including viral infection, the accumulation of misfolded proteins, and starvation. The phosphorylation of eIF2α is carried out by a family of four kinases, PERK (PKR-like ER kinase), PKR (protein kinase double-stranded RNA-dependent), GCN2 (general control non-derepressible-2), and HRI (heme-regulated inhibitor). Each primarily responds to a distinct type of stress or stresses. Thus, while significant sequence similarity exists between the eIF2α kinases in their kinase domains, underlying their common role in phosphorylating eIF2α, additional unique features determine the regulation of these four proteins, that is, what signals activate them. This review will describe the structure of each eIF2α kinase and discuss how this is linked to their activation and function. In parallel to the general translational attenuation elicited by eIF2α kinase activation the translation of stress-induced mRNAs, most notably activating transcription factor 4 (ATF4) is enhanced and these set in motion cascades of gene expression constituting the integrated stress response (ISR), which seek to remediate stress and restore homeostasis. Depending on the cellular context and concurrent signaling pathways active, however, translational attenuation can also facilitate apoptosis. Accordingly, the role of the kinases in determining cell fate will also be discussed.
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Affiliation(s)
- Neysan Donnelly
- Apoptosis Research Center, National University of Ireland, Galway, Ireland
- School of Natural Sciences, National University of Ireland, Galway, Ireland
- Present Address: Department of Molecular Cell Biology, Max Planck Institute of Biochemistry, Am Klopferspitz 18, Martinsried, Munich, 82152 Germany
| | - Adrienne M. Gorman
- Apoptosis Research Center, National University of Ireland, Galway, Ireland
- School of Natural Sciences, National University of Ireland, Galway, Ireland
| | - Sanjeev Gupta
- Apoptosis Research Center, National University of Ireland, Galway, Ireland
- School of Medicine, National University of Ireland, Galway, Ireland
| | - Afshin Samali
- Apoptosis Research Center, National University of Ireland, Galway, Ireland
- School of Natural Sciences, National University of Ireland, Galway, Ireland
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Proteome analysis of vaccinia virus IHD-W-infected HEK 293 cells with 2-dimensional gel electrophoresis and MALDI-PSD-TOF MS of on solid phase support N-terminally sulfonated peptides. Virol J 2011; 8:380. [PMID: 21806805 PMCID: PMC3169512 DOI: 10.1186/1743-422x-8-380] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2011] [Accepted: 08/01/2011] [Indexed: 11/14/2022] Open
Abstract
Background Despite the successful eradication of smallpox by the WHO-led vaccination programme, pox virus infections remain a considerable health threat. The possible use of smallpox as a bioterrorism agent as well as the continuous occurrence of zoonotic pox virus infections document the relevance to deepen the understanding for virus host interactions. Since the permissiveness of pox infections is independent of hosts surface receptors, but correlates with the ability of the virus to infiltrate the antiviral host response, it directly depends on the hosts proteome set. In this report the proteome of HEK293 cells infected with Vaccinia Virus strain IHD-W was analyzed by 2-dimensional gel electrophoresis and MALDI-PSD-TOF MS in a bottom-up approach. Results The cellular and viral proteomes of VACV IHD-W infected HEK293 cells, UV-inactivated VACV IHD-W-treated as well as non-infected cells were compared. Derivatization of peptides with 4-sulfophenyl isothiocyanate (SPITC) carried out on ZipTipμ-C18 columns enabled protein identification via the peptides' primary sequence, providing improved s/n ratios as well as signal intensities of the PSD spectra. The expression of more than 24 human proteins was modulated by the viral infection. Effects of UV-inactivated and infectious viruses on the hosts' proteome concerning energy metabolism and proteins associated with gene expression and protein-biosynthesis were quite similar. These effects might therefore be attributed to virus entry and virion proteins. However, the modulation of proteins involved in apoptosis was clearly correlated to infectious viruses. Conclusions The proteome analysis of infected cells provides insight into apoptosis modulation, regulation of cellular gene expression and the regulation of energy metabolism. The confidence of protein identifications was clearly improved by the peptides' derivatization with SPITC on a solid phase support. Some of the identified proteins have not been described in the context of poxvirus infections before and need to be further characterised to identify their meaning for apoptosis modulation and pathogenesis.
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Colombo E, Alcalay M, Pelicci PG. Nucleophosmin and its complex network: a possible therapeutic target in hematological diseases. Oncogene 2011; 30:2595-609. [PMID: 21278791 DOI: 10.1038/onc.2010.646] [Citation(s) in RCA: 164] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Nucleophosmin (NPM, also known as B23, numatrin or NO38) is a ubiquitously expressed phosphoprotein belonging to the nucleoplasmin family of chaperones. NPM is mainly localized in the nucleolus where it exerts many of its functions, but a proportion of the protein continuously shuttles between the nucleus and the cytoplasm. A growing number of cellular proteins have been described as physical interactors of NPM, and consequently, NPM is thought to have a relevant role in diverse cellular functions, including ribosome biogenesis, centrosome duplication, DNA repair and response to stress. NPM has been implicated in the pathogenesis of several human malignancies and intriguingly, it has been described both as an activating oncogene and a tumor suppressor, depending on cell type and protein levels. In fact, increased NPM expression is associated with different types of solid tumors whereas an impairment of NPM function is characteristic of a subgroup of hematolologic malignancies. A large body of experimental evidence links the deregulation of specific NPM functions to cellular transformation, yet the molecular mechanisms through which NPM contributes to tumorigenesis remain elusive. In this review, we have summarized current knowledge concerning NPM functions, and attempted to interpret its multifaceted and sometimes apparently contradictory activities in the context of both normal cellular homeostasis and neoplastic transformation.
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Affiliation(s)
- E Colombo
- Department of Experimental Oncology, European Institute of Oncology, Milan, Italy.
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The Multifunctional Nucleolar Protein Nucleophosmin/NPM/B23 and the Nucleoplasmin Family of Proteins. THE NUCLEOLUS 2011. [PMCID: PMC7121557 DOI: 10.1007/978-1-4614-0514-6_10] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The nucleophosmin (NPM)/nucleoplasmin family of nuclear chaperones has three members: NPM1, NPM2, and NPM3. Nuclear chaperones serve to ensure proper assembly of nucleosomes and proper formation of higher order structures of chromatin. In fact, this family of proteins has such diverse functions in cellular processes such as chromatin remodeling, ribosome biogenesis, genome stability, centrosome replication, cell cycle, transcriptional regulation, apoptosis, and tumor suppression. Of the members of this family, NPM1 is the most studied and is the main focus of this review. NPM2 and NPM3 are less well characterized, and are also discussed wherever appropriate. The structure–function relationship of NPM proteins has largely been worked out. Other than the many processes in which NPM1 takes part, the major interest comes from its involvement in human cancers, particularly acute myeloid leukemia (AML). Its significance stems from the fact that AML with mutated NPM1 accounts for ∼30% of all AML cases and usually has good prognosis. Its clinical importance also comes from its involvement in virus replication, particularly in the era of outbreaks of infectious diseases.
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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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Galli A, Ceni E, Mello T, Polvani S, Tarocchi M, Buccoliero F, Lisi F, Cioni L, Ottanelli B, Foresta V, Mastrobuoni G, Moneti G, Pieraccini G, Surrenti C, Milani S. Thiazolidinediones inhibit hepatocarcinogenesis in hepatitis B virus-transgenic mice by peroxisome proliferator-activated receptor gamma-independent regulation of nucleophosmin. Hepatology 2010; 52:493-505. [PMID: 20683949 DOI: 10.1002/hep.23669] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
UNLABELLED Antidiabetic thiazolidinediones (TZD) have in vitro antiproliferative effect in epithelial cancers, including hepatocellular carcinoma (HCC). The effective anticancer properties and the underlying molecular mechanisms of these drugs in vivo remain unclear. In addition, the primary biological target of TZD, the ligand-dependent transcription factor peroxisome proliferator-activated receptor gamma (PPARgamma), is up-regulated in HCC and seems to provide tumor-promoting responses. The aim of our study was to evaluate whether chronic administration of TZD may affect hepatic carcinogenesis in vivo in relation to PPARgamma expression and activity. The effect of TZD oral administration for 26 weeks was tested on tumor formation in PPARgamma-expressing and PPARgamma-deficient mouse models of hepatic carcinogenesis. Proteomic analysis was performed in freshly isolated hepatocytes by differential in gel electrophoresis and mass spectrometry analysis. Identified TZD targets were confirmed in cultured PPARgamma-deficient hepatocytes. TZD administration in hepatitis B virus (HBV)-transgenic mice (TgN[Alb1HBV]44Bri) reduced tumor incidence in the liver, inhibiting hepatocyte proliferation and increasing apoptosis. PPARgamma deletion in hepatocytes of HBV-transgenic mice (Tg[HBV]CreKOgamma) did not modify hepatic carcinogenesis but increased the TZD antitumorigenic effect. Proteomic analysis identified nucleophosmin (NPM) as a TZD target in PPARgamma-deficient hepatocytes. TZD inhibited NPM expression at protein and messenger RNA levels and decreased NPM promoter activity. TZD inhibition of NPM was associated with the induction of p53 phosphorylation and p21 expression. CONCLUSION These findings suggest that chronic administration of TZD has anticancer activity in the liver via inhibition of NPM expression and indicate that these drugs might be useful for HCC chemoprevention and treatment.
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Affiliation(s)
- Andrea Galli
- Gastroenterology Unit, Department of Clinical Pathophysiology, University of Florence, Florence, Italy.
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Du W, Zhou Y, Pike S, Pang Q. NPM phosphorylation stimulates Cdk1, overrides G2/M checkpoint and increases leukemic blasts in mice. Carcinogenesis 2009; 31:302-10. [PMID: 19933706 DOI: 10.1093/carcin/bgp270] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
An elevated level of nucleophosmin (NPM) is often found in actively proliferative cells including human tumors. To identify the regulatory role for NPM phosphorylation in proliferation and cell cycle control, a series of mutants targeting the consensus cyclin-dependent kinase (CDK) phosphorylation sites was created to mimic or abrogate either single-site or multi-site phosphorylation. Simultaneous inactivation of two CDK phosphorylation sites at Ser10 and Ser70 (NPM-AA) induced G(2)/M cell cycle arrest, phosphorylation of Cdk1 at Tyr15 (Cdc2(Tyr15)) and increased cytoplasmic accumulation of Cdc25C. Strikingly, stress-induced Cdk1(Tyr15) and Cdc25C sequestration was suppressed by expression of a phosphomimetic NPM mutant created on the same CDK sites (S10E/S70E, NPM-EE). Further analysis revealed that phosphorylation of NPM at both Ser10 and Ser70 was required for proper interaction between Cdk1 and Cdc25C. Moreover, NPM-EE directly bound to Cdc25C and prevented phosphorylation of Cdc25C at Ser216 during mitosis. Finally, NPM-EE overrided stress-induced G(2)/M arrest and increased leukemia blasts in a NOD/SCID xenograft model. Thus, these findings reveal a novel function of NPM on regulation of cell cycle progression, in which phosphorylation of NPM controls cell cycle progression at G(2)/M transition through modulation of Cdk1 and Cdc25C activities.
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Affiliation(s)
- Wei Du
- Division of Experimental Hematology and Cancer Biology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229, USA
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Meani N, Alcalay M. Role of nucleophosmin in acute myeloid leukemia. Expert Rev Anticancer Ther 2009; 9:1283-94. [PMID: 19761432 DOI: 10.1586/era.09.84] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Nucleophosmin (NPM) is a nucleolar phosphoprotein implicated in the regulation of multiple cellular functions, which possesses both oncogenic and tumor-suppressor properties. Mutations of the NPM1 gene leading to the expression of a cytoplasmic mutant protein, NPMc+, are the most frequent genetic abnormalities found in acute myeloid leukemias. Acute myeloid leukemias with mutated NPM1 have distinct characteristics, including a significant association with a normal karyotype, involvement of different hematopoietic lineages, a specific gene-expression profile and clinically, a better response to induction therapy and a favorable prognosis. NPMc+ maintains the capacity of wild-type NPM to interact with a variety of cellular proteins, and impairs their activity by delocalizing them to the cytoplasm. In this review we summarize recent discoveries concerning NPM function, and discuss their possible impact on the pathogenesis of acute myeloid leukemias with mutated NPM1.
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Affiliation(s)
- Natalia Meani
- Istituto Europeo di Oncologia, IFOM-IEO Campus, Via Adamello 16, 20139 Milan, Italy.
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Ranjan P, Bowzard JB, Schwerzmann JW, Jeisy-Scott V, Fujita T, Sambhara S. Cytoplasmic nucleic acid sensors in antiviral immunity. Trends Mol Med 2009; 15:359-68. [PMID: 19665430 DOI: 10.1016/j.molmed.2009.06.003] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2009] [Revised: 06/10/2009] [Accepted: 06/10/2009] [Indexed: 12/17/2022]
Abstract
The innate immune system uses pattern recognition receptors (PRRs) to sense invading microbes and initiate a rapid protective response. PRRs bind and are activated by structural motifs, such as nucleic acids or bacterial and fungal cell wall components, collectively known as pathogen-associated molecular patterns. PRRs that recognize pathogen-derived nucleic acids are present in vesicular compartments and in the cytosol of most cell types. Here, we review recent studies of these cytosolic sensors, focusing on the nature of the ligands for DNA-dependent activator of interferon (DAI)-regulatory factors, absent in melanoma 2 (AIM2), and the retinoic acid-inducible gene I-like helicase (RLH) family of receptors, the basis of ligand recognition and the signaling pathways triggered by the activation of these receptors. An increased understanding of these molecular aspects of innate immunity will guide the development of novel antiviral therapeutics.
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Affiliation(s)
- Priya Ranjan
- Influenza Division, Centers for Disease Control and Prevention, Atlanta, GA 30333, USA
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Mittelstadt M, Frump A, Khuu T, Fowlkes V, Handy I, Patel CV, Patel RC. Interaction of human tRNA-dihydrouridine synthase-2 with interferon-induced protein kinase PKR. Nucleic Acids Res 2007; 36:998-1008. [PMID: 18096616 PMCID: PMC2241914 DOI: 10.1093/nar/gkm1129] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
PKR is an interferon (IFN)-induced protein kinase, which is involved in regulation of antiviral innate immunity, stress signaling, cell proliferation and programmed cell death. Although a low amount of PKR is expressed ubiquitously in all cell types in the absence of IFNs, PKR expression is induced at transcriptional level by IFN. PKR's enzymatic activity is activated by its binding to one of its activators. Double-stranded (ds) RNA, protein activator PACT and heparin are the three known activators of PKR. Activation of PKR in cells leads to a general block in protein synthesis due to phosphorylation of eIF2α on serine 51 by PKR. PKR activation is regulated very tightly in mammalian cells and a prolonged activation of PKR leads to apoptosis. Thus, positive and negative regulation of PKR activation is important for cell viability and function. The studies presented here describe human dihydrouridine synthase-2 (hDUS2) as a novel regulator of PKR. We originally identified hDUS2 as a protein interacting with PACT in a yeast two-hybrid screen. Further characterization revealed that hDUS2 also interacts with PKR through its dsRNA binding/dimerization domain and inhibits its kinase activity. Our results suggest that hDUS2 may act as a novel inhibitor of PKR in cells.
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Affiliation(s)
- Megan Mittelstadt
- Department of Biological Sciences, University of South Carolina Columbia, SC 29208, USA
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Garcia MA, Muñoz-Fontela C, Collado M, Marcos-Villar L, Esteban M, Rivas C. Novel and unexpected role for the tumor suppressor ARF in viral infection surveillance. Future Virol 2007. [DOI: 10.2217/17460794.2.6.625] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Virus infection induces the synthesis of interferons which, in turn, stimulate the expression of hundreds of cellular genes, any of those denominated viral-stress-inducible genes. Among interferon-upregulated genes, also triggered by oncogenic viruses, several tumor-suppressor genes can also be listed. A correlation between the tumor suppressor alternative reading frame (ARF) and virus replication was noted some time ago. Yang and colleagues in 2001 demonstrated that p14ARF modulated the cytolytic effect of the E1B-deleted adenovirus ONYX-015 in mesothelioma cells with wild-type p53, and expression of p14ARF attenuated the cytolytic effect of the virus. Later, in 2006, Garcia and colleagues identified ARF as a gene product with a role in reducing the sensitivity of cells to infection by several viruses, showing an inverse relationship between doses of ARF and levels of virus replication. Additionally, the same authors presented a number of experiments designed to illustrate the molecular mechanisms underlying the decrease of virus replication upon ARF overexpression, demonstrating a p53-independent ARF function. ARF is the latest tumor suppressor added to the list of the cellular genes upregulated by type I interferon that possesses antiviral activity. The antiviral role of other tumor suppressor pathways targeted by both interferons and oncogenic viruses requires further investigation.
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Affiliation(s)
- Maria Angel Garcia
- Centro Nacional de Biotecnología CSIC, Campus Universidad Autónoma, Madrid 28049, Spain
| | - Cesar Muñoz-Fontela
- Mount Sinai School of Medicine, Dept of Oncological Sciences, One Gustave L. Levy Place. Box 1130, NY 10029, USA
| | - Manuel Collado
- Spanish National Cancer Centre (CNIO), 3 Melchor Fernández Almagro, Madrid 28029, Spain
| | - Laura Marcos-Villar
- Universidad Complutense de Madrid, Departamento de Microbiología II, Plaza Ramón y Cajal s/n, Madrid 28040, Spain
| | - Mariano Esteban
- Centro Nacional de Biotecnología, CSIC, Campus Universidad Autónoma, Madrid 28049, Spain
| | - Carmen Rivas
- Centro Nacional de Biotecnología, CSIC, Campus Universidad Autónoma, Madrid 28049, Spain
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Park YD, Lyou YJ, Yang JM. Two-dimensional electrophoresis analyses of atopic dermatitis and the chances to detect new candidate proteins by the variations in immobilized pH gradient strips. J Dermatol Sci 2007; 47:9-17. [PMID: 17353112 DOI: 10.1016/j.jdermsci.2007.02.004] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2006] [Revised: 01/18/2007] [Accepted: 02/13/2007] [Indexed: 01/11/2023]
Abstract
BACKGROUND Proteomic approaches, one of the high-throughput technologies, have been used to search for the proteins that are abnormally expressed in human diseases. The atopic dermatitis (AD)-associated genes or proteins are gradually being reported. OBJECTIVE In accordance with recent reports, we conducted the serial proteomic studies to compare with the protein expression level and to find a critical protein associated with AD. METHODS We applied two-dimensional electrophoresis (2-DE) coupled with MADI-TOF as well as LC-MS/MS to detect dysregulated protein in the AD proteome obtained from the patient-derived primary cells. Real-time PCR was also conducted to compare with the proteomic results in the transcriptional level. RESULTS We successfully detected new AD-associated proteins in the AD-derived fibroblasts 2D-PAGE studies due to the IPG strip variations after conducting MALDI-TOF mass spectrometry and identification of the proteins. From the real-time PCR quantifications, we found that the altered expression of caldesmon 1 isoform 5, nucleophosmin 1, esterase D and chloride intracellular channel 4 were well matched both at the transcriptional and translational levels, and this suggested that these proteins may have important involvement with the pathogenesis of AD. CONCLUSION By simply repeating the trials with changing the commercial strips with different lot numbers in the 2D-PAGE analysis, this provided us with new finding in the AD-derived samples. This approach we used may increase the chances of finding new candidate proteins in the clinical samples and it may also be applicable for proteomic studies of other diseases.
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Affiliation(s)
- Yong-Doo Park
- Department of Dermatology, Sungkyunkwan University School of Medicine, Samsung Medical Center, Seoul 135-710, Republic of Korea
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Ganapathi KA, Austin KM, Lee CS, Dias A, Malsch MM, Reed R, Shimamura A. The human Shwachman-Diamond syndrome protein, SBDS, associates with ribosomal RNA. Blood 2007; 110:1458-65. [PMID: 17475909 PMCID: PMC1975835 DOI: 10.1182/blood-2007-02-075184] [Citation(s) in RCA: 113] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Shwachman-Diamond syndrome (SDS) is an autosomal recessive disorder characterized by bone marrow failure, exocrine pancreatic dysfunction, and leukemia predisposition. Mutations in the SBDS gene are identified in most patients with SDS. SBDS encodes a highly conserved protein of unknown function. Data from SBDS orthologs suggest that SBDS may play a role in ribosome biogenesis or RNA processing. Human SBDS is enriched in the nucleolus, the major cellular site of ribosome biogenesis. Here we report that SBDS nucleolar localization is dependent on active rRNA transcription. Cells from patients with SDS or Diamond-Blackfan anemia are hypersensitive to low doses of actinomycin D, an inhibitor of rRNA transcription. The addition of wild-type SBDS complements the actinomycin D hypersensitivity of SDS patient cells. SBDS migrates together with the 60S large ribosomal subunit in sucrose gradients and coprecipitates with 28S ribosomal RNA (rRNA). Loss of SBDS is not associated with a discrete block in rRNA maturation or with decreased levels of the 60S ribosomal subunit. SBDS forms a protein complex with nucleophosmin, a multifunctional protein implicated in ribosome biogenesis and leukemogenesis. Our studies support the addition of SDS to the growing list of human bone marrow failure syndromes involving the ribosome.
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Affiliation(s)
- Karthik A Ganapathi
- Department of Pediatric Hematology, Children's Hospital Boston, Boston, MA, USA
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García MA, Meurs EF, Esteban M. The dsRNA protein kinase PKR: virus and cell control. Biochimie 2007; 89:799-811. [PMID: 17451862 DOI: 10.1016/j.biochi.2007.03.001] [Citation(s) in RCA: 471] [Impact Index Per Article: 27.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2007] [Accepted: 03/02/2007] [Indexed: 10/23/2022]
Abstract
The IFN-induced double-stranded RNA-dependent protein kinase (PKR) is one of the four mammalian serine-threonine kinases (the three others being HRI, GCN2 and PERK) that phosphorylate the eIF2 alpha translation initiation factor, in response to stress signals, mainly as a result of viral infections. eIF2 alpha phosphorylation results in arrest of translation of both cellular and viral mRNAs, an efficient way to inhibit virus replication. The particularity of PKR is to activate by binding to dsRNA through two N terminal dsRNA binding motifs (dsRBM). PKR activation during a viral infection represents a threat for several viruses, which have therefore evolved to express PKR inhibitors, such as the Vaccinia E3L and K3L proteins. The function of PKR can also be regulated by cellular proteins, either positively (RAX/PACT; Mda7) or negatively (p58IPK, TRBP, nucleophosmin, Hsp90/70). PKR can provoke apoptosis, in part through its ability to control protein translation, but the situation appears to be more complex, as NF-kappaB, ATF-3 and p53 have also been implicated. PKR-induced apoptosis involves mainly the FADD/caspase 8 pathway, while the mitochondrial APAF/caspase 9 pathway is also engaged. As a consequence of the effects of PKR on translation, transcription and apoptosis, PKR can function to control cell growth and cell differentiation, and its activity can be controlled by the action of several oncogenes.
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Affiliation(s)
- M A García
- Department of Molecular and Cellular Biology, Centro Nacional de Biotecnología, CSIC, Ciudad Universitaria Cantoblanco, 28049 Madrid, Spain
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Abstract
It was in the 1930s that telomeres (from the Greek telos = end and meros = part) were first recognized as essential structures at the ends of the chromosomes and were shown to be important for chromosomal stability (Muller HJ: The remaking of chromosomes. The Collecting Net-Woods Hole 1938: 13: 181-198, McClintock B, The stability of broken ends of chromosomes in Zea mays. Genetics 1041: 26: 234-282). However, it was only in 1978 that the first telomeric sequence was identified -- in the protocoa Tetrahymena, a single cell organism that at a certain stage of development has many identical minichromosomes with twice as many telomeres (Blackburn EH and Gall JG. A tandemly repeated sequence at the termini of the extrachromosomal ribosomal RNA genes in Tetrahymena. J. Mol. Biol. 1978: 120: 33-53.). Today we know that telomeres form specialized, three-dimensional DNA-protein structures and fulfil important capping functions. Besides, telomeric DNA is essential as ''access DNA'' for those cells that are not able to counteract loss of DNA during replication because they do not express telomerase, the enzyme responsible for telomere length maintenance. Since telomerase is mostly found in tumor cells and inhibition correlates with telomere shortening and finally growth inhibition, telomerase and lately also the telomeres themselves have become attractive targets for anti-cancer therapy. This review aims to critically throw light on different therapeutical approaches and comes to the conclusion that telomeres may be the better targets for cancer therapeutics.
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Affiliation(s)
- Petra Boukamp
- Department of Genetics and Skin Carcinogenesis, German Cancer Research Center, Heidelberg, Germany.
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García MA, Gil J, Ventoso I, Guerra S, Domingo E, Rivas C, Esteban M. Impact of protein kinase PKR in cell biology: from antiviral to antiproliferative action. Microbiol Mol Biol Rev 2007; 70:1032-60. [PMID: 17158706 PMCID: PMC1698511 DOI: 10.1128/mmbr.00027-06] [Citation(s) in RCA: 590] [Impact Index Per Article: 34.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
The double-stranded RNA-dependent protein kinase PKR is a critical mediator of the antiproliferative and antiviral effects exerted by interferons. Not only is PKR an effector molecule on the cellular response to double-stranded RNA, but it also integrates signals in response to Toll-like receptor activation, growth factors, and diverse cellular stresses. In this review, we provide a detailed picture on how signaling downstream of PKR unfolds and what are the ultimate consequences for the cell fate. PKR activation affects both transcription and translation. PKR phosphorylation of the alpha subunit of eukaryotic initiation factor 2 results in a blockade on translation initiation. However, PKR cannot avoid the translation of some cellular and viral mRNAs bearing special features in their 5' untranslated regions. In addition, PKR affects diverse transcriptional factors such as interferon regulatory factor 1, STATs, p53, activating transcription factor 3, and NF-kappaB. In particular, how PKR triggers a cascade of events involving IKK phosphorylation of IkappaB and NF-kappaB nuclear translocation has been intensively studied. At the cellular and organism levels PKR exerts antiproliferative effects, and it is a key antiviral agent. A point of convergence in both effects is that PKR activation results in apoptosis induction. The extent and strength of the antiviral action of PKR are clearly understood by the findings that unrelated viral proteins of animal viruses have evolved to inhibit PKR action by using diverse strategies. The case for the pathological consequences of the antiproliferative action of PKR is less understood, but therapeutic strategies aimed at targeting PKR are beginning to offer promising results.
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Affiliation(s)
- M A García
- Department of Molecular and Cellular Biology, Centro Nacional de Biotecnología, Ciudad Universitaria Cantoblanco, 28049 Madrid, Spain
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Pelletier CL, Maggi LB, Brady SN, Scheidenhelm DK, Gutmann DH, Weber JD. TSC1 sets the rate of ribosome export and protein synthesis through nucleophosmin translation. Cancer Res 2007; 67:1609-17. [PMID: 17308101 PMCID: PMC2859708 DOI: 10.1158/0008-5472.can-06-2875] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Nucleophosmin (B23) is a nucleolar phosphoprotein that has been implicated in numerous cellular processes. In particular, nucleophosmin interacts with nucleolar components of newly synthesized ribosomes to promote ribosome nuclear export. Nucleophosmin is a classic mitogen-induced protein, with changes in its expression correlating with growth factor stimulation. In this study, we examined the underlying mechanism of nucleophosmin induction and showed that hyperproliferative signals emanating from oncogenic H-Ras(V12) cause tremendous increases in nucleophosmin protein expression. Nucleophosmin protein accumulation was dependent on mammalian target of rapamycin (mTOR) activation, as rapamycin completely prevented nucleophosmin induction. Consistent with this finding, genetic ablation of Tsc1, a major upstream inhibitor of mTOR, resulted in nucleophosmin protein induction through increased translation of existing nucleophosmin mRNAs. Increases in nucleophosmin protein accumulation were suppressed by reintroduction of TSC1. Induction of nucleophosmin through Tsc1 loss resulted in a greater pool of actively translating ribosomes in the cytoplasm, higher overall rates of protein synthesis, and increased cell proliferation, all of which were dependent on efficient nucleophosmin nuclear export. Nucleophosmin protein accumulation in the absence of Tsc1 promoted the nuclear export of maturing ribosome subunits, providing a mechanistic link between TSC1/mTOR signaling, nucleophosmin-mediated nuclear export of ribosome subunits, protein synthesis levels, and cell growth.
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Affiliation(s)
- Corey L. Pelletier
- Division of Molecular Oncology, Department of Internal Medicine, Siteman Cancer Center, Washington University School of Medicine, St. Louis, Missouri
| | - Leonard B. Maggi
- Division of Molecular Oncology, Department of Internal Medicine, Siteman Cancer Center, Washington University School of Medicine, St. Louis, Missouri
| | - Suzanne N. Brady
- Division of Molecular Oncology, Department of Internal Medicine, Siteman Cancer Center, Washington University School of Medicine, St. Louis, Missouri
| | | | - David H. Gutmann
- Department of Neurology, Washington University School of Medicine, St. Louis, Missouri
| | - Jason D. Weber
- Division of Molecular Oncology, Department of Internal Medicine, Siteman Cancer Center, Washington University School of Medicine, St. Louis, Missouri
- Department of Cell Biology, Washington University School of Medicine, St. Louis, Missouri
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Mayer D, Molawi K, Martínez-Sobrido L, Ghanem A, Thomas S, Baginsky S, Grossmann J, García-Sastre A, Schwemmle M. Identification of cellular interaction partners of the influenza virus ribonucleoprotein complex and polymerase complex using proteomic-based approaches. J Proteome Res 2007; 6:672-82. [PMID: 17269724 PMCID: PMC2577182 DOI: 10.1021/pr060432u] [Citation(s) in RCA: 184] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Cellular factors that associate with the influenza A viral ribonucleoprotein (vRNP) are presumed to play important roles in the viral life cycle. To date, interaction screens using individual vRNP components, such as the nucleoprotein or viral polymerase subunits, have revealed few cellular interaction partners. To improve this situation, we performed comprehensive, proteomics-based screens to identify cellular factors associated with the native vRNP and viral polymerase complexes. Reconstituted vRNPs were purified from human cells using Strep-tagged viral nucleoprotein (NP-Strep) as bait, and co-purified cellular factors were identified by mass spectrometry (MS). In parallel, reconstituted native influenza A polymerase complexes were isolated using tandem affinity purification (TAP)-tagged polymerase subunits as bait, and co-purified cellular factors were again identified by MS. Using these techniques, we identified 41 proteins that co-purified with NP-Strep-enriched vRNPs and four cellular proteins that co-purified with the viral polymerase complex. Two of the polymerase-associated factors, importin-beta3 and PARP-1, represent novel interaction partners. Most cellular proteins previously shown to interact with either viral NP and/or vRNP were also identified using our method, demonstrating its sensitivity. Co-immunoprecipitation studies in virus-infected cells using selected novel interaction partners, including nucleophosmin (NPM), confirmed their association with vRNP. Immunofluorescence analysis further revealed that NPM is recruited to sites of viral transcription and replication in infected cells. Additionally, overexpression of NPM resulted in increased viral polymerase activity, indicating its role in viral RNA synthesis. In summary, the proteomics-based approaches used in this study represent powerful tools to identify novel vRNP-associated cellular factors for further characterization.
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Affiliation(s)
- Daniel Mayer
- Department of Virology, Institute for Medical Microbiology and Hygiene, University of Freiburg, Germany
| | - Kaaweh Molawi
- Department of Virology, Institute for Medical Microbiology and Hygiene, University of Freiburg, Germany
- Department of Microbiology, Box 1124, Mount Sinai School of Medicine, 1 Gustave L Levy Place, New York, NY 10029
| | - Luis Martínez-Sobrido
- Department of Microbiology, Box 1124, Mount Sinai School of Medicine, 1 Gustave L Levy Place, New York, NY 10029
| | - Alexander Ghanem
- Department of Virology, Institute for Medical Microbiology and Hygiene, University of Freiburg, Germany
| | - Stefan Thomas
- Department of Virology, Institute for Medical Microbiology and Hygiene, University of Freiburg, Germany
| | - Sacha Baginsky
- Institute of Plant Sciences, Swiss Federal Institute of Technology. ETH Zentrum, LFW E, CH-8092 Zurich, Switzerland
| | - Jonas Grossmann
- Institute of Plant Sciences, Swiss Federal Institute of Technology. ETH Zentrum, LFW E, CH-8092 Zurich, Switzerland
| | - Adolfo García-Sastre
- Department of Microbiology, Box 1124, Mount Sinai School of Medicine, 1 Gustave L Levy Place, New York, NY 10029
| | - Martin Schwemmle
- Department of Virology, Institute for Medical Microbiology and Hygiene, University of Freiburg, Germany
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28
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Bennett RL, Blalock WL, Abtahi DM, Pan Y, Moyer SA, May WS. RAX, the PKR activator, sensitizes cells to inflammatory cytokines, serum withdrawal, chemotherapy, and viral infection. Blood 2006; 108:821-9. [PMID: 16861340 PMCID: PMC1617065 DOI: 10.1182/blood-2005-11-006817] [Citation(s) in RCA: 69] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
While the interferon (IFN)-inducible double-stranded RNA (dsRNA)-dependent protein kinase PKR is reported to initiate apoptosis in some instances, the mechanism by which diverse stress stimuli activate PKR remains unknown. Now we report that RAX, the only known cellular activator for PKR, initiates PKR activation in response to a broad range of stresses including serum deprivation, cytotoxic cytokine or chemotherapy treatment, or viral infection. Thus, knock-down of RAX expression by 80% using small interfering RNA (siRNA) prevents IFNgamma/tumor necrosis factor alpha (TNFalpha)-induced PKR activation and eIF2alpha phosphorylation, IkappaB degradation, IRF-1 expression, and STAT1 phosphorylation, resulting in enhanced murine embryonic fibroblast (MEF) cell survival. In contrast, expression of exogenous RAX, but not of the nonphosphorylatable, dominant-negative RAX(S18A) mutant, sensitizes cells to IFNgamma/TNFalpha, mitomycin C (MMC), or serum deprivation in association with increased PKR activity and apoptosis. Furthermore, RAX(S18A) expression in Fanconi anemia complementation group C-null MEF cells not only prevents PKR activation but also blocks hypersensitivity to IFNgamma/TNFalpha or mitomycin C that results in enhanced apoptosis. In addition, reduced RAX expression facilitates productive viral infection with vesicular stomatitis virus (VSV) and promotes anchorage-independent colony growth of MEF cells. Collectively, these data indicate that RAX may function as a negative regulator of growth that is required to activate PKR in response to a broad range of apoptosis-inducing stress.
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Affiliation(s)
- Richard L Bennett
- Department of Immunology and Molecular Genetics, Shands Cancer Center, University of Florida, Gainesville, USA
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29
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García MA, Collado M, Muñoz-Fontela C, Matheu A, Marcos-Villar L, Arroyo J, Esteban M, Serrano M, Rivas C. Antiviral action of the tumor suppressor ARF. EMBO J 2006; 25:4284-92. [PMID: 16957780 PMCID: PMC1570439 DOI: 10.1038/sj.emboj.7601302] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2006] [Accepted: 07/27/2006] [Indexed: 01/12/2023] Open
Abstract
Oncogenic viruses frequently target the pathways controlled by tumor suppressor genes, suggesting an extra function for these proteins as antiviral factors. The control exerted by the tumor suppressor Arf on cellular proliferation is crucial to restrict tumor development; however, a potential contribution of Arf to prevent viral infectivity has remained unexplored. In the present study, we investigated the consequences of loss or increased expression of Arf on viral infection. Our results reveal that ARF expression is induced by interferon and after viral infection. Furthermore, we show that ARF protects against viral infection in a gene dosage-dependent manner, and that this antiviral action is mediated in part by PKR through a mechanism that involves ARF-induced release of PKR from nucleophosmin complexes. Finally, Arf-null mice were hypersensitive to viral infection compared to wild-type mice. Together, our results reveal a novel and unexpected role for the tumor suppressor ARF in viral infection surveillance.
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Affiliation(s)
- María A García
- Centro Nacional de Biotecnología (CNB), Universidad Autónoma de Madrid, Madrid, Spain
| | - Manuel Collado
- Spanish National Cancer Centre (CNIO), 3 Melchor Fernández Almagro, Madrid, Spain
| | - César Muñoz-Fontela
- Departamento de Microbiología II, Universidad Complutense de Madrid (UCM), Plaza Ramón y Cajal s/n, Madrid, Spain
| | - Ander Matheu
- Spanish National Cancer Centre (CNIO), 3 Melchor Fernández Almagro, Madrid, Spain
| | - Laura Marcos-Villar
- Departamento de Microbiología II, Universidad Complutense de Madrid (UCM), Plaza Ramón y Cajal s/n, Madrid, Spain
| | - Javier Arroyo
- Departamento de Microbiología II, Universidad Complutense de Madrid (UCM), Plaza Ramón y Cajal s/n, Madrid, Spain
| | - Mariano Esteban
- Centro Nacional de Biotecnología (CNB), Universidad Autónoma de Madrid, Madrid, Spain
| | - Manuel Serrano
- Spanish National Cancer Centre (CNIO), 3 Melchor Fernández Almagro, Madrid, Spain
- Spanish National Cancer Center (CNIO), 3 Melchor Fernández Almagro, Madrid 28029, Spain. Tel.: +34 91 7328032; Fax: +34 91 7328028; E-mail:
| | - Carmen Rivas
- Departamento de Microbiología II, Universidad Complutense de Madrid (UCM), Plaza Ramón y Cajal s/n, Madrid, Spain
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30
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Abstract
NPM1 is a crucial gene to consider in the context of the genetics and biology of cancer. NPM1 is frequently overexpressed, mutated, rearranged and deleted in human cancer. Traditionally regarded as a tumour marker and a putative proto-oncogene, it has now also been attributed with tumour-suppressor functions. Therefore, NPM can contribute to oncogenesis through many mechanisms. The aim of this review is to analyse the role of NPM in cancer, and examine how deregulated NPM activity (either gain or loss of function) can contribute to tumorigenesis.
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Affiliation(s)
- Silvia Grisendi
- Cancer Biology & Genetics Program, Department of Pathology, Sloan-Kettering Institute, Memorial Sloan-Kettering Cancer Center, New York, New York 10021, USA
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31
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Sarioglu H, Brandner S, Jacobsen C, Meindl T, Schmidt A, Kellermann J, Lottspeich F, Andrae U. Quantitative analysis of 2,3,7,8-tetrachlorodibenzo-p-dioxin-induced proteome alterations in 5L rat hepatoma cells using isotope-coded protein labels. Proteomics 2006; 6:2407-21. [PMID: 16548065 DOI: 10.1002/pmic.200500680] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
In an effort to contribute to a better understanding of the hepatic toxicity of the ubiquitous environmental pollutant and hepatocarcinogen 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), a comprehensive quantitative proteome analysis was performed on 5L rat hepatoma cells exposed to 1 nM TCDD for 8 h. Changes in the abundances of individual protein species in TCDD-treated cells as compared to untreated cells were analysed using the nongel-based isotope-coded protein label (ICPL) method [Schmidt, A., Kellermann, J., Lottspeich, F., Proteomics 2005, 5, 4-15]. 89 proteins were identified as up- or down-regulated by TCDD. For the majority of the altered proteins, an impact of TCDD on their abundance had not been known before. Due to the physicochemical properties or the translational regulation of a large number of the affected proteins, their alteration would have escaped detection by gel-based methods for proteome analysis and by standard mRNA expression profiling, respectively. The identified proteins with TCDD-altered abundance include several proteins implicated in cell cycle regulation, growth factor signalling and the control of apoptosis. The results thus provide new starting-points for the investigation of specific aspects of the toxicity and carcinogenicity of dioxin in liver.
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Affiliation(s)
- Hakan Sarioglu
- GSF - Forschungszentrum für Umwelt und Gesundheit, Institut für Toxikologie, Neuherberg, Germany
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32
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Sautkina EN, Potapenko NA, Vladimirova NM. State of nucleolar proteins B23/nucleophosmin and UBF in HeLa cells during apoptosis induced by tumor necrosis factor. BIOCHEMISTRY (MOSCOW) 2006; 71:634-43. [PMID: 16827655 DOI: 10.1134/s0006297906060071] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
The structural state of two major nucleolar proteins, UBF and B23/nucleophosmin (both monomeric and oligomeric forms), was for the first time established in HeLa cells treated with apoptosis inducers: tumor necrosis factor (TNF-alpha), emetine, and their combination. The treatment of the cells with either TNF-alpha or emetine did not induce apoptosis and affect the state of UBF and nucleophosmin (both monomers and oligomers). Apoptosis was rather pronounced only if HeLa cells were treated with a mixture of TNF-alpha and emetine. States of the UBF and B23 proteins were analyzed in samples containing 25, 45, and 100% of cells with apoptotic nuclei. It was shown by immunoblotting that TNF-alpha-induced apoptosis of HeLa cells was associated with proteolysis of UBF and production of a 76-kD fragment, the content of which increased in correlation with the fraction of apoptotically changed cells. The N- and C-terminal amino acid sequences of UBF and its 76-kD fragment were characterized, and the site of the apoptosis-induced specific proteolysis was identified. As differentiated from UBF, protein B23 did not undergo proteolytic degradation during the TNF-alpha-induced apoptosis of HeLa cells and its content was unchanged even in the cell fraction with fragmentation of virtually all nuclei. However, the ratio between the monomeric and oligomeric states of B23 protein was changed in apoptotic cells, and apoptosis-specific forms of nucleophosmin were detected.
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Affiliation(s)
- E N Sautkina
- Shemyakin and Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, 117997, Russia.
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Li J, Sejas DP, Rani R, Koretsky T, Bagby GC, Pang Q. Nucleophosmin regulates cell cycle progression and stress response in hematopoietic stem/progenitor cells. J Biol Chem 2006; 281:16536-45. [PMID: 16608843 DOI: 10.1074/jbc.m601386200] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Nucleophosmin (NPM) is a multifunctional protein frequently overexpressed in actively proliferating cells. Strong evidence indicates that NPM is required for embryonic development and genomic stability. Here we report that NPM enhances the proliferative potential of hematopoietic stem cells (HSCs) and increases their survival upon stress challenge. Both short term liquid culture and clonogenic progenitor cell assays show a selective expansion of NPM-overexpressing HSCs. Interestingly, HSCs infected with NPM retrovirus show significantly reduced commitment to myeloid differentiation compared with vector-transduced cells, and majority of the NPM-overexpressing cells remains primitive during a 5-day culture. Bone marrow transplantation experiments demonstrate that NPM promotes the self-renewal of long term repopulating HSCs while attenuated their commitment to myeloid differentiation. NPM overexpression induces rapid entry of HSCs into the cell cycle and suppresses the expression of several negative cell cycle regulators that are associated with G(1)-to-S transition. NPM knockdown elevates expression of these negative regulators and exacerbates stress-induced cell cycle arrest. Finally, overexpression of NPM promotes the survival and recovery of HSCs and progenitors after exposure to DNA damage, oxidative stress, and hematopoietic injury both in vivo and in vitro. DNA repair kinetics study suggests that NPM has a role in reducing the susceptibility of chromosomal DNA to damage rather than promoting DNA damage repair. Together, these results indicate that NPM plays an important role in hematopoiesis via mechanisms involving modulation of HSC/progenitor cell cycle progression and stress response.
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Affiliation(s)
- June Li
- Division of Experimental Hematology, Cincinnati Children's Hospital Medical Center, 3333 Burnet Avenue, Cincinnati, OH 45229, USA
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Li J, Zhang X, Sejas DP, Pang Q. Negative regulation of p53 by nucleophosmin antagonizes stress-induced apoptosis in human normal and malignant hematopoietic cells. Leuk Res 2005; 29:1415-23. [PMID: 15964625 DOI: 10.1016/j.leukres.2005.05.005] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2005] [Revised: 04/30/2005] [Accepted: 05/03/2005] [Indexed: 11/28/2022]
Abstract
Nucleophosmin (NPM) is a multifunctional protein frequently overexpressed in actively proliferating cells including tumor and stem cells. Here we show that NPM acts as a cellular p53 negative regulator to protect normal and malignant hematopoietic cells from stress-induced apoptosis. Overexpression of NPM suppresses stress-induced apoptosis in the granulocyte-macrophage colony-stimulating factor (GM-CSF)-dependent myeloid cell line MO7e and the lymphoblast HSC536 cells derived from a Fanconi anemia (FA) patient. In addition, suppression of NPM expression by small interfering RNA targeting NPM in normal lymphoblasts and FA-associated acute myelogenous leukemia (AML) cells increases DNA damage-induced apoptosis. However, overexpression of the mutant NPMDeltaC, which lacks the p53-interacting domain, fails to confer cellular resistance to stress-induced apoptosis, suggesting that NPM protects cells from apoptotic cell death through a mechanism involving p53. Indeed, using the genetically matched p53 wild-type (WT) and null mouse bone marrow (BM) cells, we demonstrate that forced expression of NPM protects against ionizing irradiation (IR)-induced apoptosis of WT but not p53-null BM cells. Moreover, NPM inhibits IR-induced p53 transactivation, and interacts with p53 in hematopoietic cells. Thus, these results indicate an important role for NPM in regulation of p53-dependent apoptotic response and implicate a potential effect in cancer therapy.
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Affiliation(s)
- June Li
- Division of Experimental Hematology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229, USA
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35
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Macé G, Bogliolo M, Guervilly JH, Dugas du Villard JA, Rosselli F. 3R coordination by Fanconi anemia proteins. Biochimie 2005; 87:647-58. [PMID: 15935541 DOI: 10.1016/j.biochi.2005.05.003] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Fanconi anemia (FA) is a recessive cancer prone syndrome featuring bone marrow failure and hypersensitivity to DNA crosslinks. Nine FA genes have been isolated so far. The biochemical function(s) of the FA proteins remain(s) poorly determined. However, a large consensus exists on the evidence that, to cope with DNA cross-links, a cell needs a functional FA pathway. In this review, we resume current understanding of how the FA pathway works in response to DNA damage and how it is integrated in a complex network of proteins involved in the maintenance of the genetic stability.
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Affiliation(s)
- Gaëtane Macé
- Institut Gustave-Roussy PR2, UPR2169 du CNRS, 39, rue Camille-Desmoulins, 94805 Villejuif cedex, France
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36
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Oh S, Im H, Oh E, Lee J, Khim JY, Mun J, Kim Y, Lee E, Kim J, Sul D. Effects of benzo(a)pyrene on protein expression in Jurkat T-cells. Proteomics 2005; 4:3514-26. [PMID: 15529408 DOI: 10.1002/pmic.200400981] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous environmental pollutants of air, water and soil, and are produced by the incomplete combustion of organic materials. The International Agency for Research on Cancer has characterized PAHs as carcinogens. In this study, we investigated the effects of benzo(a)pyrene (B(a)P), which is the most carcinogenic member of the PAHs, on Jurkat cell protein by proteomic analysis. Jurkat cells were treated with various concentrations of B(a)P (0, 2.5, 5, 10, 20 or 40 microM) for 24 or 48 h and 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium and lactate dehydrogenase assays were carried out to determine cytotoxicity and a Comet assay was used to determinate genotoxicity. The cytotoxicity assays showed that 2.5 microM of B(a)P was the maximal concentration that did not cause any toxicity, but nevertheless, at this level B(a)P produced significant DNA damage in Jurkat cells at 48 h. Proteomic analysis using three different pI ranges and large two-dimensional gel electrophoresis showed 3427 protein spots. A total of 46 (13 up- and 33 down-regulated) proteins were identified as biomarkers of B(a)P and showed dose-dependent expressions in Jurkat T-cell line exposed to B(a)P. Of these, 27 protein spots were identified by matrix-assisted laser desorption/ionization-time of flight mass spectrometry. Two functionally differentiated protein groups were found. The protein group involving apoptosis and tumor suppression were found to be up-regulated, and B(a)P down-regulated enzyme was involved in energy metabolism, DNA synthesis and in cell structure and motility.
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Affiliation(s)
- Sangnam Oh
- School of Life Sciences and Biotechnology, Korea University, Seoul, Korea
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