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Baños-Jaime B, Corrales-Guerrero L, Pérez-Mejías G, Rejano-Gordillo CM, Velázquez-Campoy A, Martínez-Cruz LA, Martínez-Chantar ML, De la Rosa MA, Díaz-Moreno I. Phosphorylation at the disordered N-end makes HuR accumulate and dimerize in the cytoplasm. Nucleic Acids Res 2024; 52:8552-8565. [PMID: 38966993 PMCID: PMC11317137 DOI: 10.1093/nar/gkae564] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2023] [Revised: 05/30/2024] [Accepted: 07/02/2024] [Indexed: 07/06/2024] Open
Abstract
Human antigen R (HuR) is an RNA binding protein mainly involved in maintaining the stability and controlling the translation of mRNAs, critical for immune response, cell survival, proliferation and apoptosis. Although HuR is a nuclear protein, its mRNA translational-related function occurs at the cytoplasm, where the oligomeric form of HuR is more abundant. However, the regulation of nucleo-cytoplasmic transport of HuR and its connection with protein oligomerization remain unclear. In this work, we describe the phosphorylation of Tyr5 as a new hallmark for HuR activation. Our biophysical, structural and computational assays using phosphorylated and phosphomimetic HuR proteins demonstrate that phosphorylation of Tyr5 at the disordered N-end stretch induces global changes on HuR dynamics and conformation, modifying the solvent accessible surface of the HuR nucleo-cytoplasmic shuttling (HNS) sequence and releasing regions implicated in HuR dimerization. These findings explain the preferential cytoplasmic accumulation of phosphorylated HuR in HeLa cells, aiding to comprehend the mechanisms underlying HuR nucleus-cytoplasm shuttling and its later dimerization, both of which are relevant in HuR-related pathogenesis.
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Affiliation(s)
- Blanca Baños-Jaime
- Institute for Chemical Research (IIQ), Scientific Research Center "Isla de la Cartuja" (cicCartuja), University of Seville - CSIC, Seville 41092, Spain
| | - Laura Corrales-Guerrero
- Institute for Chemical Research (IIQ), Scientific Research Center "Isla de la Cartuja" (cicCartuja), University of Seville - CSIC, Seville 41092, Spain
| | - Gonzalo Pérez-Mejías
- Institute for Chemical Research (IIQ), Scientific Research Center "Isla de la Cartuja" (cicCartuja), University of Seville - CSIC, Seville 41092, Spain
| | - Claudia M Rejano-Gordillo
- Centre for Biomedical Research Network of Hepatic and Digestive Diseases (CIBERehd), Madrid 28029, Spain
- Liver Disease Lab, BRTA CIC bioGUNE, Derio 48160 Bizkaia, Spain
- Department of Biochemistry and Molecular Biology, Faculty of Sciences, University of Extremadura; University Institute of Biosanitary Research of Extremadura (INUBE), Badajoz 06071, Spain
| | - Adrián Velázquez-Campoy
- Institute for Biocomputation and Physic of Complex Systems (BIFI), Joint Unit GBsC-CSIC-BIFI, University of Zaragoza, Zaragoza 50018, Spain
- Departament of Biochemistry and Molecular and Cellular Biology, University of Zaragoza, Zaragoza 50009, Spain
- Institute for Health Research of Aragón (IIS Aragon), Zaragoza 50009, Spain
| | - Luis Alfonso Martínez-Cruz
- Centre for Biomedical Research Network of Hepatic and Digestive Diseases (CIBERehd), Madrid 28029, Spain
- Liver Disease Lab, BRTA CIC bioGUNE, Derio 48160 Bizkaia, Spain
| | - María Luz Martínez-Chantar
- Centre for Biomedical Research Network of Hepatic and Digestive Diseases (CIBERehd), Madrid 28029, Spain
- Liver Disease Lab, BRTA CIC bioGUNE, Derio 48160 Bizkaia, Spain
| | - Miguel A De la Rosa
- Institute for Chemical Research (IIQ), Scientific Research Center "Isla de la Cartuja" (cicCartuja), University of Seville - CSIC, Seville 41092, Spain
| | - Irene Díaz-Moreno
- Institute for Chemical Research (IIQ), Scientific Research Center "Isla de la Cartuja" (cicCartuja), University of Seville - CSIC, Seville 41092, Spain
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Alemi F, Poornajaf Y, Hosseini F, Vahedian V, Gharekhani M, Shoorei H, Taheri M. Interaction between lncRNAs and RNA-binding proteins (RBPs) influences DNA damage response in cancer chemoresistance. Mol Biol Rep 2024; 51:308. [PMID: 38366290 DOI: 10.1007/s11033-024-09288-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2023] [Accepted: 01/25/2024] [Indexed: 02/18/2024]
Abstract
The DNA damage response (DDR) is a crucial cellular signaling pathway activated in response to DNA damage, including damage caused by chemotherapy. Chemoresistance, which refers to the resistance of cancer cells to the effects of chemotherapy, poses a significant challenge in cancer treatment. Understanding the relationship between DDR and chemoresistance is vital for devising strategies to overcome this resistance and improve treatment outcomes. Long non-coding RNAs (lncRNAs) are a class of RNA molecules that do not code for proteins but play important roles in various biological processes, including cancer development and chemoresistance. RNA-binding proteins (RBPs) are a group of proteins that bind to RNA molecules and regulate their functions. The interaction between lncRNAs and RBPs has been found to regulate gene expression at the post-transcriptional level, thereby influencing various cellular processes, including DDR signaling pathways. Multiple studies have demonstrated that lncRNAs can interact with RBPs to modulate the expression of genes involved in cancer chemoresistance by impacting DDR signaling pathways. Conversely, RBPs can regulate the expression and function of lncRNAs involved in DDR. Exploring these interactions can provide valuable insights for the development of innovative therapeutic approaches to overcome chemoresistance in cancer patients. This review article aims to summarize recent research on the interaction between lncRNAs and RBPs during cancer chemotherapy, with a specific focus on DDR pathways.
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Affiliation(s)
- Forough Alemi
- Department of Biochemistry and Clinical Laboratories, Faculty of Medicine, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Yadollah Poornajaf
- Faculty of Medicine, Birjand University of Medical Sciences, Birjand, Iran
| | - Foroogh Hosseini
- Department of Biological Sciences, Lehigh University, Bethlehem, PA, USA
| | - Vahid Vahedian
- Department of Medical Clinic, Division of Hematology/Oncology and Cellular Therapy, Faculty of Medicine, University of Sao Paulo (FMUSP), Sao Paulo, Brazil
| | - Mahdi Gharekhani
- Clinical Research Development Unit of Tabriz Valiasr Hospital, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Hamed Shoorei
- Clinical Research Development Unit of Tabriz Valiasr Hospital, Tabriz University of Medical Sciences, Tabriz, Iran.
- Rooyesh Infertility Center, Birjand University of Medical Sciences, Birjand, Iran.
- Cellular and Molecular Research Center, Birjand University of Medical Sciences, Birjand, Iran.
| | - Mohammad Taheri
- Institute of Human Genetics, Jena University Hospital, Jena, Germany.
- Urology and Nephrology Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
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Troschel FM, Eich HT, Greve B. Tackling the HuRdle of radioresistance: a radiation perspective on the RNA-binding protein HuR. Transl Cancer Res 2023; 12:3223-3226. [PMID: 38192977 PMCID: PMC10774030 DOI: 10.21037/tcr-23-1866] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2023] [Accepted: 11/22/2023] [Indexed: 01/10/2024]
Affiliation(s)
| | - Hans Theodor Eich
- Department of Radiation Oncology, Münster University Hospital, Münster, Germany
| | - Burkhard Greve
- Department of Radiation Oncology, Münster University Hospital, Münster, Germany
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Mehta M, Raguraman R, Ramesh R, Munshi A. RNA binding proteins (RBPs) and their role in DNA damage and radiation response in cancer. Adv Drug Deliv Rev 2022; 191:114569. [PMID: 36252617 PMCID: PMC10411638 DOI: 10.1016/j.addr.2022.114569] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2022] [Revised: 09/27/2022] [Accepted: 09/29/2022] [Indexed: 01/24/2023]
Abstract
Traditionally majority of eukaryotic gene expression is influenced by transcriptional and post-transcriptional events. Alterations in the expression of proteins that act post-transcriptionally can affect cellular signaling and homeostasis. RNA binding proteins (RBPs) are a family of proteins that specifically bind to RNAs and are involved in post-transcriptional regulation of gene expression and important cellular processes such as cell differentiation and metabolism. Deregulation of RNA-RBP interactions and any changes in RBP expression or function can lead to various diseases including cancer. In cancer cells, RBPs play an important role in regulating the expression of tumor suppressors and oncoproteins involved in various cell-signaling pathways. Several RBPs such as HuR, AUF1, RBM38, LIN28, RBM24, tristetrapolin family and Musashi play critical roles in various types of cancers and their aberrant expression in cancer cells makes them an attractive therapeutic target for cancer treatment. In this review we provide an overview of i). RBPs involved in cancer progression and their mechanism of action ii). the role of RBPs, including HuR, in breast cancer progression and DNA damage response and iii). explore RBPs with emphasis on HuR as therapeutic target for breast cancer therapy.
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Affiliation(s)
- Meghna Mehta
- Department of Radiation Oncology, The University of Oklahoma Health Sciences Center, Oklahoma City, OK 73013, USA; Stephenson Cancer Center, The University of Oklahoma Health Sciences Center, Oklahoma City, OK 73013, USA
| | - Rajeswari Raguraman
- Department of Pathology, The University of Oklahoma Health Sciences Center, Oklahoma City, OK 73013, USA; Stephenson Cancer Center, The University of Oklahoma Health Sciences Center, Oklahoma City, OK 73013, USA
| | - Rajagopal Ramesh
- Department of Pathology, The University of Oklahoma Health Sciences Center, Oklahoma City, OK 73013, USA; Stephenson Cancer Center, The University of Oklahoma Health Sciences Center, Oklahoma City, OK 73013, USA
| | - Anupama Munshi
- Department of Radiation Oncology, The University of Oklahoma Health Sciences Center, Oklahoma City, OK 73013, USA; Stephenson Cancer Center, The University of Oklahoma Health Sciences Center, Oklahoma City, OK 73013, USA.
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AU-Rich Element RNA Binding Proteins: At the Crossroads of Post-Transcriptional Regulation and Genome Integrity. Int J Mol Sci 2021; 23:ijms23010096. [PMID: 35008519 PMCID: PMC8744917 DOI: 10.3390/ijms23010096] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2021] [Revised: 12/17/2021] [Accepted: 12/18/2021] [Indexed: 12/14/2022] Open
Abstract
Genome integrity must be tightly preserved to ensure cellular survival and to deter the genesis of disease. Endogenous and exogenous stressors that impose threats to genomic stability through DNA damage are counteracted by a tightly regulated DNA damage response (DDR). RNA binding proteins (RBPs) are emerging as regulators and mediators of diverse biological processes. Specifically, RBPs that bind to adenine uridine (AU)-rich elements (AREs) in the 3' untranslated region (UTR) of mRNAs (AU-RBPs) have emerged as key players in regulating the DDR and preserving genome integrity. Here we review eight established AU-RBPs (AUF1, HuR, KHSRP, TIA-1, TIAR, ZFP36, ZFP36L1, ZFP36L2) and their ability to maintain genome integrity through various interactions. We have reviewed canonical roles of AU-RBPs in regulating the fate of mRNA transcripts encoding DDR genes at multiple post-transcriptional levels. We have also attempted to shed light on non-canonical roles of AU-RBPs exploring their post-translational modifications (PTMs) and sub-cellular localization in response to genotoxic stresses by various factors involved in DDR and genome maintenance. Dysfunctional AU-RBPs have been increasingly found to be associated with many human cancers. Further understanding of the roles of AU-RBPS in maintaining genomic integrity may uncover novel therapeutic strategies for cancer.
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Ravel-Chapuis A, Haghandish A, Daneshvar N, Jasmin BJ, Côté J. A novel CARM1-HuR axis involved in muscle differentiation and plasticity misregulated in spinal muscular atrophy. Hum Mol Genet 2021; 31:1453-1470. [PMID: 34791230 DOI: 10.1093/hmg/ddab333] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2021] [Revised: 10/19/2021] [Accepted: 10/19/2021] [Indexed: 11/14/2022] Open
Abstract
Spinal muscular atrophy (SMA) is characterized by the loss of alpha motor neurons in the spinal cord and a progressive muscle weakness and atrophy. SMA is caused by loss-of-function mutations and/or deletions in the survival of motor neuron (SMN) gene. The role of SMN in motor neurons has been extensively studied, but its function and the consequences of its loss in muscle has also emerged as a key aspect of SMA pathology. In this study, we explore the molecular mechanisms involved in muscle defects in SMA. First, we show in C2C12 myoblasts, that arginine methylation by CARM1 controls myogenic differentiation. More specifically, the methylation of HuR on K217 regulates HuR levels and subcellular localization during myogenic differentiation, and the formation of myotubes. Furthermore, we demonstrate that SMN and HuR interact in C2C12 myoblasts. Interestingly, the SMA-causing E134K point mutation within the SMN Tudor domain, and CARM1 depletion, modulate the SMN-HuR interaction. In addition, using the Smn2B/- mouse model, we report that CARM1 levels are markedly increased in SMA muscles and that HuR fails to properly respond to muscle denervation, thereby affecting the regulation of its mRNA targets. Altogether, our results show a novel CARM1-HuR axis in the regulation of muscle differentiation and plasticity as well as in the aberrant regulation of this axis caused by the absence of SMN in SMA muscle. With the recent developments of therapeutics targeting motor neurons, this study further indicates the need for more global therapeutic approaches for SMA.
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Affiliation(s)
- Aymeric Ravel-Chapuis
- Department of Cellular and Molecular Medicine, Faculty of Medicine, University of Ottawa, Ottawa, ON K1H 8M5, Canada
- Eric Poulin Centre for Neuromuscular Disease, Faculty of Medicine, University of Ottawa, Ottawa, ON K1H 8M5, Canada
| | - Amir Haghandish
- Department of Cellular and Molecular Medicine, Faculty of Medicine, University of Ottawa, Ottawa, ON K1H 8M5, Canada
- Eric Poulin Centre for Neuromuscular Disease, Faculty of Medicine, University of Ottawa, Ottawa, ON K1H 8M5, Canada
| | - Nasibeh Daneshvar
- Department of Cellular and Molecular Medicine, Faculty of Medicine, University of Ottawa, Ottawa, ON K1H 8M5, Canada
- Eric Poulin Centre for Neuromuscular Disease, Faculty of Medicine, University of Ottawa, Ottawa, ON K1H 8M5, Canada
| | - Bernard J Jasmin
- Department of Cellular and Molecular Medicine, Faculty of Medicine, University of Ottawa, Ottawa, ON K1H 8M5, Canada
- Eric Poulin Centre for Neuromuscular Disease, Faculty of Medicine, University of Ottawa, Ottawa, ON K1H 8M5, Canada
| | - Jocelyn Côté
- Department of Cellular and Molecular Medicine, Faculty of Medicine, University of Ottawa, Ottawa, ON K1H 8M5, Canada
- Eric Poulin Centre for Neuromuscular Disease, Faculty of Medicine, University of Ottawa, Ottawa, ON K1H 8M5, Canada
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Vadivel Gnanasundram S, Bonczek O, Wang L, Chen S, Fahraeus R. p53 mRNA Metabolism Links with the DNA Damage Response. Genes (Basel) 2021; 12:1446. [PMID: 34573428 PMCID: PMC8465283 DOI: 10.3390/genes12091446] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2021] [Revised: 09/10/2021] [Accepted: 09/13/2021] [Indexed: 12/14/2022] Open
Abstract
Human cells are subjected to continuous challenges by different genotoxic stress attacks. DNA damage leads to erroneous mutations, which can alter the function of oncogenes or tumor suppressors, resulting in cancer development. To circumvent this, cells activate the DNA damage response (DDR), which mainly involves cell cycle regulation and DNA repair processes. The tumor suppressor p53 plays a pivotal role in the DDR by halting the cell cycle and facilitating the DNA repair processes. Various pathways and factors participating in the detection and repair of DNA have been described, including scores of RNA-binding proteins (RBPs) and RNAs. It has become increasingly clear that p53's role is multitasking, and p53 mRNA regulation plays a prominent part in the DDR. This review is aimed at covering the p53 RNA metabolism linked to the DDR and highlights the recent findings.
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Affiliation(s)
| | - Ondrej Bonczek
- Department of Medical Biosciences, Umeå University, 901-87 Umeå, Sweden; (O.B.); (L.W.); (S.C.)
- RECAMO, Masaryk Memorial Cancer Institute, Zluty Kopec 7, 656-53 Brno, Czech Republic
| | - Lixiao Wang
- Department of Medical Biosciences, Umeå University, 901-87 Umeå, Sweden; (O.B.); (L.W.); (S.C.)
| | - Sa Chen
- Department of Medical Biosciences, Umeå University, 901-87 Umeå, Sweden; (O.B.); (L.W.); (S.C.)
| | - Robin Fahraeus
- Department of Medical Biosciences, Umeå University, 901-87 Umeå, Sweden; (O.B.); (L.W.); (S.C.)
- RECAMO, Masaryk Memorial Cancer Institute, Zluty Kopec 7, 656-53 Brno, Czech Republic
- Inserm UMRS1131, Institut de Genetique Moleculaire, Universite Paris 7, Hopital St Louis, F-75010 Paris, France
- International Centre for Cancer Vaccine Science, University of Gdansk, 80-822 Gdansk, Poland
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8
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Krismer K, Bird MA, Varmeh S, Handly ED, Gattinger A, Bernwinkler T, Anderson DA, Heinzel A, Joughin BA, Kong YW, Cannell IG, Yaffe MB. Transite: A Computational Motif-Based Analysis Platform That Identifies RNA-Binding Proteins Modulating Changes in Gene Expression. Cell Rep 2021; 32:108064. [PMID: 32846122 PMCID: PMC8204639 DOI: 10.1016/j.celrep.2020.108064] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2019] [Revised: 06/28/2020] [Accepted: 08/03/2020] [Indexed: 12/13/2022] Open
Abstract
RNA-binding proteins (RBPs) play critical roles in regulating gene expression by modulating splicing, RNA stability, and protein translation. Stimulus-induced alterations in RBP function contribute to global changes in gene expression, but identifying which RBPs are responsible for the observed changes remains an unmet need. Here, we present Transite, a computational approach that systematically infers RBPs influencing gene expression through changes in RNA stability and degradation. As a proof of principle, we apply Transite to RNA expression data from human patients with non-small-cell lung cancer whose tumors were sampled at diagnosis or after recurrence following treatment with platinum-based chemotherapy. Transite implicates known RBP regulators of the DNA damage response and identifies hnRNPC as a new modulator of chemotherapeutic resistance, which we subsequently validated experimentally. Transite serves as a framework for the identification of RBPs that drive cell-state transitions and adds additional value to the vast collection of publicly available gene expression datasets. Krismer et al. present a computational approach to identify RNA-binding proteins (RBPs) that modulate post-transcriptional control of gene expression using RNA expression data as inputs. By applying this approach to publicly available patient datasets, they identify and experimentally confirm that the RBP hnRNPC contributes to chemotherapy resistance in lung cancer.
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Affiliation(s)
- Konstantin Krismer
- Computer Science and Artificial Intelligence Laboratory, Massachusetts Institute of Technology, 32 Vassar Street, Cambridge, MA 02139, USA; Center for Precision Cancer Medicine, Massachusetts Institute of Technology, 500 Main Street, Cambridge, MA 02142, USA; Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, 500 Main Street, Cambridge, MA 02142, USA; Department of Biological Engineering, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139, USA; Department for Medical and Bioinformatics, University of Applied Sciences Upper Austria, Softwarepark 11, 4232 Hagenberg, Austria
| | - Molly A Bird
- Center for Precision Cancer Medicine, Massachusetts Institute of Technology, 500 Main Street, Cambridge, MA 02142, USA; Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, 500 Main Street, Cambridge, MA 02142, USA; Department of Biological Engineering, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139, USA
| | - Shohreh Varmeh
- Center for Precision Cancer Medicine, Massachusetts Institute of Technology, 500 Main Street, Cambridge, MA 02142, USA; Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, 500 Main Street, Cambridge, MA 02142, USA
| | - Erika D Handly
- Center for Precision Cancer Medicine, Massachusetts Institute of Technology, 500 Main Street, Cambridge, MA 02142, USA; Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, 500 Main Street, Cambridge, MA 02142, USA; Department of Biological Engineering, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139, USA
| | - Anna Gattinger
- Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, 500 Main Street, Cambridge, MA 02142, USA; Department for Medical and Bioinformatics, University of Applied Sciences Upper Austria, Softwarepark 11, 4232 Hagenberg, Austria
| | - Thomas Bernwinkler
- Center for Precision Cancer Medicine, Massachusetts Institute of Technology, 500 Main Street, Cambridge, MA 02142, USA; Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, 500 Main Street, Cambridge, MA 02142, USA; Department for Medical and Bioinformatics, University of Applied Sciences Upper Austria, Softwarepark 11, 4232 Hagenberg, Austria
| | - Daniel A Anderson
- Synthetic Biology Center, Massachusetts Institute of Technology, 500 Technology Square, Cambridge, MA 02139, USA; Department of Biological Engineering, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139, USA
| | - Andreas Heinzel
- Department for Medical and Bioinformatics, University of Applied Sciences Upper Austria, Softwarepark 11, 4232 Hagenberg, Austria
| | - Brian A Joughin
- Center for Precision Cancer Medicine, Massachusetts Institute of Technology, 500 Main Street, Cambridge, MA 02142, USA; Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, 500 Main Street, Cambridge, MA 02142, USA; Department of Biological Engineering, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139, USA
| | - Yi Wen Kong
- Center for Precision Cancer Medicine, Massachusetts Institute of Technology, 500 Main Street, Cambridge, MA 02142, USA; Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, 500 Main Street, Cambridge, MA 02142, USA.
| | - Ian G Cannell
- Center for Precision Cancer Medicine, Massachusetts Institute of Technology, 500 Main Street, Cambridge, MA 02142, USA; Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, 500 Main Street, Cambridge, MA 02142, USA; Cancer Research UK Cambridge Institute, University of Cambridge, Li Ka Shing Centre, Robinson Way, Cambridge CB2 0RE, UK.
| | - Michael B Yaffe
- Center for Precision Cancer Medicine, Massachusetts Institute of Technology, 500 Main Street, Cambridge, MA 02142, USA; Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, 500 Main Street, Cambridge, MA 02142, USA; Department of Biological Engineering, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139, USA; Broad Institute of MIT and Harvard, 415 Main Street, Cambridge, MA 02142, USA; Department of Biology, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139, USA; Divisions of Acute Care Surgery, Trauma and Surgical Critical Care, and Surgical Oncology, Beth Israel Deaconess Medical Center, 330 Brookline Avenue, Boston, MA 02215, USA.
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Mohammadi E, Sadoughi F, Younesi S, Karimian A, Asemi Z, Farsad-Akhtar N, Jahanbakhshi F, Jamilian H, Yousefi B. The molecular mechanism of nuclear signaling for degradation of cytoplasmic DNA: Importance in DNA damage response and cancer. DNA Repair (Amst) 2021; 103:103115. [PMID: 33915415 DOI: 10.1016/j.dnarep.2021.103115] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2021] [Revised: 04/03/2021] [Accepted: 04/04/2021] [Indexed: 11/17/2022]
Abstract
This review summarizes and addresses non-coding RNAs (rRNA, tRNA, Vault and Y RNA, snRNA, and miRNA) cytoplasmic decay pathways, the molecules, enzymes, and modifications such as uridylation, which play vital roles in the degradation processes in various eukaryotic organisms. Plus, SIRT1's role in fundamental cellular processes, including autophagy, DNA repair, DNA damage response (DDR), and the molecular mechanisms, is explored. Further, the HuR (an RNA-binding protein) impact on the expression of genes following DNA damage, and the pathways that regulate HuR function, which is through phosphorylation by Chk1/Cdk1 and Chk2, are specified. Finally, the role of DIF1/ Rnr2-Rnr4 in DDR has been discussed.
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Affiliation(s)
- Erfan Mohammadi
- Drug Applied Research Center, Tabriz University of Medical Sciences, Tabriz, Iran; Department of Biology, Faculty of Natural Sciences, University of Tabriz, Tabriz, Iran.
| | - Fatemeh Sadoughi
- Research Center for Biochemistry and Nutrition in Metabolic Diseases, Institute for Basic Sciences, Kashan University of Medical Sciences, Kashan, Iran.
| | - Simin Younesi
- School of Health and Biomedical Sciences RMIT University, Melbourne, Vic., Australia.
| | - Ansar Karimian
- Drug Applied Research Center, Tabriz University of Medical Sciences, Tabriz, Iran.
| | - Zatollah Asemi
- Research Center for Biochemistry and Nutrition in Metabolic Diseases, Institute for Basic Sciences, Kashan University of Medical Sciences, Kashan, Iran.
| | - Nader Farsad-Akhtar
- Department of Biology, Faculty of Natural Sciences, University of Tabriz, Tabriz, Iran.
| | - Fahime Jahanbakhshi
- Department of Gynecology and Obstetrics, School of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
| | - Hamidreza Jamilian
- Department of Psychiatry, Arak University of Medical Sciences, Arak, Iran.
| | - Bahman Yousefi
- Drug Applied Research Center, Tabriz University of Medical Sciences, Tabriz, Iran.
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STAU2 protein level is controlled by caspases and the CHK1 pathway and regulates cell cycle progression in the non-transformed hTERT-RPE1 cells. BMC Mol Cell Biol 2021; 22:16. [PMID: 33663378 PMCID: PMC7934504 DOI: 10.1186/s12860-021-00352-y] [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: 08/21/2020] [Accepted: 02/22/2021] [Indexed: 11/10/2022] Open
Abstract
Background Staufen2 (STAU2) is an RNA binding protein involved in the posttranscriptional regulation of gene expression. In neurons, STAU2 is required to maintain the balance between differentiation and proliferation of neural stem cells through asymmetric cell division. However, the importance of controlling STAU2 expression for cell cycle progression is not clear in non-neuronal dividing cells. We recently showed that STAU2 transcription is inhibited in response to DNA-damage due to E2F1 displacement from the STAU2 gene promoter. We now study the regulation of STAU2 steady-state levels in unstressed cells and its consequence for cell proliferation. Results CRISPR/Cas9-mediated and RNAi-dependent STAU2 depletion in the non-transformed hTERT-RPE1 cells both facilitate cell proliferation suggesting that STAU2 expression influences pathway(s) linked to cell cycle controls. Such effects are not observed in the CRISPR STAU2-KO cancer HCT116 cells nor in the STAU2-RNAi-depleted HeLa cells. Interestingly, a physiological decrease in the steady-state level of STAU2 is controlled by caspases. This effect of peptidases is counterbalanced by the activity of the CHK1 pathway suggesting that STAU2 partial degradation/stabilization fines tune cell cycle progression in unstressed cells. A large-scale proteomic analysis using STAU2/biotinylase fusion protein identifies known STAU2 interactors involved in RNA translation, localization, splicing, or decay confirming the role of STAU2 in the posttranscriptional regulation of gene expression. In addition, several proteins found in the nucleolus, including proteins of the ribosome biogenesis pathway and of the DNA damage response, are found in close proximity to STAU2. Strikingly, many of these proteins are linked to the kinase CHK1 pathway, reinforcing the link between STAU2 functions and the CHK1 pathway. Indeed, inhibition of the CHK1 pathway for 4 h dissociates STAU2 from proteins involved in translation and RNA metabolism. Conclusions These results indicate that STAU2 is involved in pathway(s) that control(s) cell proliferation, likely via mechanisms of posttranscriptional regulation, ribonucleoprotein complex assembly, genome integrity and/or checkpoint controls. The mechanism by which STAU2 regulates cell growth likely involves caspases and the kinase CHK1 pathway. Supplementary Information The online version contains supplementary material available at 10.1186/s12860-021-00352-y.
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11
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Ionizing Radiation and Translation Control: A Link to Radiation Hormesis? Int J Mol Sci 2020; 21:ijms21186650. [PMID: 32932812 PMCID: PMC7555331 DOI: 10.3390/ijms21186650] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2020] [Accepted: 09/04/2020] [Indexed: 02/06/2023] Open
Abstract
Protein synthesis, or mRNA translation, is one of the most energy-consuming functions in cells. Translation of mRNA into proteins is thus highly regulated by and integrated with upstream and downstream signaling pathways, dependent on various transacting proteins and cis-acting elements within the substrate mRNAs. Under conditions of stress, such as exposure to ionizing radiation, regulatory mechanisms reprogram protein synthesis to translate mRNAs encoding proteins that ensure proper cellular responses. Interestingly, beneficial responses to low-dose radiation exposure, known as radiation hormesis, have been described in several models, but the molecular mechanisms behind this phenomenon are largely unknown. In this review, we explore how differences in cellular responses to high- vs. low-dose ionizing radiation are realized through the modulation of molecular pathways with a particular emphasis on the regulation of mRNA translation control.
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Murphy MR, Kleiman FE. Connections between 3' end processing and DNA damage response: Ten years later. WILEY INTERDISCIPLINARY REVIEWS. RNA 2020; 11:e1571. [PMID: 31657151 PMCID: PMC7295566 DOI: 10.1002/wrna.1571] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/23/2019] [Revised: 09/10/2019] [Accepted: 09/17/2019] [Indexed: 12/23/2022]
Abstract
Ten years ago we reviewed how the cellular DNA damage response (DDR) is controlled by changes in the functional and structural properties of nuclear proteins, resulting in a timely coordinated control of gene expression that allows DNA repair. Expression of genes that play a role in DDR is regulated not only at transcriptional level during mRNA biosynthesis but also by changing steady-state levels due to turnover of the transcripts. The 3' end processing machinery, which is important in the regulation of mRNA stability, is involved in these gene-specific responses to DNA damage. Here, we review the latest mechanistic connections described between 3' end processing and DDR, with a special emphasis on alternative polyadenylation, microRNA and RNA binding proteins-mediated deadenylation, and discuss the implications of deregulation of these steps in DDR and human disease. This article is categorized under: RNA Processing > 3' End Processing RNA-Based Catalysis > Miscellaneous RNA-Catalyzed Reactions RNA in Disease and Development > RNA in Disease.
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Affiliation(s)
- Michael Robert Murphy
- Department of Chemistry, Hunter College and Biochemistry Program, The Graduate Center, City University of New York, New York, New York
| | - Frida Esther Kleiman
- Department of Chemistry, Hunter College and Biochemistry Program, The Graduate Center, City University of New York, New York, New York
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Yang X, Sun X, Wu J, Ma J, Si P, Yin L, Zhang Y, Yan LJ, Zhang C. Regulation of the SIRT1 signaling pathway in NMDA-induced Excitotoxicity. Toxicol Lett 2020; 322:66-76. [PMID: 31945382 DOI: 10.1016/j.toxlet.2020.01.009] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2019] [Revised: 10/12/2019] [Accepted: 01/12/2020] [Indexed: 12/20/2022]
Abstract
Silent Information Regulator 1 (SIRT1), an NAD+-dependent deacetylase, contributes to the neuroprotective effect. However, intracellular signaling pathways that affect SIRT1 function remain unknown. It is well known that N-methyl-D-aspartate (NMDA) receptor activation induces calcium influx which then activates PKC, and SIRT1 is a mRNA target for HuR protein. We hypothesize that Ca2+-PKC-HuR-SIRT1 pathway modulates SIRT1 function. The present study is to investigate the potential pathway of SIRT1 in the SH-SY5Y cell line as an in vitro model of NMDA-induced neurotoxicity. The results showed that: (1) SIRT1 levels were downregulated in NMDA model; (2) NMDA induced an increase in serine phosphorylation of HuR, while inhibition of serine phosphorylation of HuR increased SIRT1 levels, promoting cell survival; (3) PKC inhibitor (Gö 6976) reversed NMDA insults and also suppressed serine phosphorylation of HuR; (4) 1,2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid (BAPTA-AM), an intracellular calcium chelator, fully reversed NMDA insults and also inhibited PKC activity evoked by NMDA. These results indicate that intracellular elevated Ca2+ activates PKC, which phosphorylates HuR and then promotes SIRT1 mRNA decay and subsequent neuronal death in NMDA model. Therefore, the study suggests that inhibition of Ca2+-PKC-HuR-SIRT1 pathway could be an effective strategy for preventing certain neurological diseases related to NMDA excitotoxicity.
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Affiliation(s)
- Xiaorong Yang
- Key Laboratory of Cellular Physiology (Shanxi Medical University), Ministry of Education, and the Department of Physiology, Shanxi Medical University, #56 Xin Jian South Road, Taiyuan 030001, Shanxi Province, PR China.
| | - Xuefei Sun
- Key Laboratory of Cellular Physiology (Shanxi Medical University), Ministry of Education, and the Department of Physiology, Shanxi Medical University, #56 Xin Jian South Road, Taiyuan 030001, Shanxi Province, PR China; The People's Hospital of Funing, Qinhuangdao 066300, Hebei Province, PR China
| | - Jinzi Wu
- Department of Pharmaceutical Sciences, UNT System College of Pharmacy, University of North Texas Health Science Center, Fort Worth, TX 76107, USA
| | - Jinteng Ma
- Key Laboratory of Cellular Physiology (Shanxi Medical University), Ministry of Education, and the Department of Physiology, Shanxi Medical University, #56 Xin Jian South Road, Taiyuan 030001, Shanxi Province, PR China
| | - Peipei Si
- Key Laboratory of Cellular Physiology (Shanxi Medical University), Ministry of Education, and the Department of Physiology, Shanxi Medical University, #56 Xin Jian South Road, Taiyuan 030001, Shanxi Province, PR China; Key Laboratory of Neurology of Hebei Province, The Second Hospital of Hebei Medical University, Shijiazhuang 050071, Hebei Province, PR China
| | - Litian Yin
- Key Laboratory of Cellular Physiology (Shanxi Medical University), Ministry of Education, and the Department of Physiology, Shanxi Medical University, #56 Xin Jian South Road, Taiyuan 030001, Shanxi Province, PR China
| | - Yu Zhang
- Key Laboratory of Cellular Physiology (Shanxi Medical University), Ministry of Education, and the Department of Physiology, Shanxi Medical University, #56 Xin Jian South Road, Taiyuan 030001, Shanxi Province, PR China
| | - Liang-Jun Yan
- Department of Pharmaceutical Sciences, UNT System College of Pharmacy, University of North Texas Health Science Center, Fort Worth, TX 76107, USA
| | - Ce Zhang
- Key Laboratory of Cellular Physiology (Shanxi Medical University), Ministry of Education, and the Department of Physiology, Shanxi Medical University, #56 Xin Jian South Road, Taiyuan 030001, Shanxi Province, PR China
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Andrade D, Mehta M, Griffith J, Oh S, Corbin J, Babu A, De S, Chen A, Zhao YD, Husain S, Roy S, Xu L, Aube J, Janknecht R, Gorospe M, Herman T, Ramesh R, Munshi A. HuR Reduces Radiation-Induced DNA Damage by Enhancing Expression of ARID1A. Cancers (Basel) 2019; 11:cancers11122014. [PMID: 31847141 PMCID: PMC6966656 DOI: 10.3390/cancers11122014] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2019] [Revised: 11/25/2019] [Accepted: 11/29/2019] [Indexed: 12/11/2022] Open
Abstract
Tumor suppressor ARID1A, a subunit of the chromatin remodeling complex SWI/SNF, regulates cell cycle progression, interacts with the tumor suppressor TP53, and prevents genomic instability. In addition, ARID1A has been shown to foster resistance to cancer therapy. By promoting non-homologous end joining (NHEJ), ARID1A enhances DNA repair. Consequently, ARID1A has been proposed as a promising therapeutic target to sensitize cancer cells to chemotherapy and radiation. Here, we report that ARID1A is regulated by human antigen R (HuR), an RNA-binding protein that is highly expressed in a wide range of cancers and enables resistance to chemotherapy and radiation. Our results indicate that HuR binds ARID1A mRNA, thereby increasing its stability in breast cancer cells. We further find that ARID1A expression suppresses the accumulation of DNA double-strand breaks (DSBs) caused by radiation and can rescue the loss of radioresistance triggered by HuR inhibition, suggesting that ARID1A plays an important role in HuR-driven resistance to radiation. Taken together, our work shows that HuR and ARID1A form an important regulatory axis in radiation resistance that can be targeted to improve radiotherapy in breast cancer patients.
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Affiliation(s)
- Daniel Andrade
- Department of Radiation Oncology, The University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA; (D.A.); (M.M.); (J.G.); (T.H.)
- Stephenson Cancer Center, The University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA; (S.O.); (A.B.); (Y.D.Z.); (R.J.); (R.R.)
| | - Meghna Mehta
- Department of Radiation Oncology, The University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA; (D.A.); (M.M.); (J.G.); (T.H.)
- Stephenson Cancer Center, The University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA; (S.O.); (A.B.); (Y.D.Z.); (R.J.); (R.R.)
| | - James Griffith
- Department of Radiation Oncology, The University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA; (D.A.); (M.M.); (J.G.); (T.H.)
| | - Sangphil Oh
- Stephenson Cancer Center, The University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA; (S.O.); (A.B.); (Y.D.Z.); (R.J.); (R.R.)
- Department of Cell Biology, The University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA
| | - Joshua Corbin
- Department of Pathology, The University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA; (J.C.)
| | - Anish Babu
- Stephenson Cancer Center, The University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA; (S.O.); (A.B.); (Y.D.Z.); (R.J.); (R.R.)
- Department of Pathology, The University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA; (J.C.)
| | - Supriyo De
- National Institute on Aging, National Institutes of Health, Baltimore, MD 21224, USA; (S.D.); (M.G.)
| | - Allshine Chen
- Department of Biostatistics and Epidemiology, The University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA;
| | - Yan D. Zhao
- Stephenson Cancer Center, The University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA; (S.O.); (A.B.); (Y.D.Z.); (R.J.); (R.R.)
- Department of Biostatistics and Epidemiology, The University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA;
| | - Sanam Husain
- Department of Pathology, The University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA; (J.C.)
| | - Sudeshna Roy
- Division of Chemical Biology and Medicinal Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA (J.A.)
| | - Liang Xu
- Department of Molecular Biosciences, University of Kansas Medical Center, Kansas City, KS 66160, USA;
| | - Jeffrey Aube
- Division of Chemical Biology and Medicinal Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA (J.A.)
| | - Ralf Janknecht
- Stephenson Cancer Center, The University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA; (S.O.); (A.B.); (Y.D.Z.); (R.J.); (R.R.)
- Department of Cell Biology, The University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA
- Department of Pathology, The University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA; (J.C.)
| | - Myriam Gorospe
- National Institute on Aging, National Institutes of Health, Baltimore, MD 21224, USA; (S.D.); (M.G.)
| | - Terence Herman
- Department of Radiation Oncology, The University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA; (D.A.); (M.M.); (J.G.); (T.H.)
- Stephenson Cancer Center, The University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA; (S.O.); (A.B.); (Y.D.Z.); (R.J.); (R.R.)
| | - Rajagopal Ramesh
- Stephenson Cancer Center, The University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA; (S.O.); (A.B.); (Y.D.Z.); (R.J.); (R.R.)
- Department of Pathology, The University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA; (J.C.)
- Graduate Program in Biomedical Sciences, The University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA
| | - Anupama Munshi
- Department of Radiation Oncology, The University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA; (D.A.); (M.M.); (J.G.); (T.H.)
- Stephenson Cancer Center, The University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA; (S.O.); (A.B.); (Y.D.Z.); (R.J.); (R.R.)
- Correspondence: ; Tel.: +1-405-271-6102; Fax: +1-405-271-2141
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Torun A, Enayat S, Sheraj I, Tunçer S, Ülgen DH, Banerjee S. Butyrate mediated regulation of RNA binding proteins in the post-transcriptional regulation of inflammatory gene expression. Cell Signal 2019; 64:109410. [DOI: 10.1016/j.cellsig.2019.109410] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2019] [Revised: 08/28/2019] [Accepted: 08/31/2019] [Indexed: 12/16/2022]
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Inhibition of Caspase-2 Translation by the mRNA Binding Protein HuR: A Novel Path of Therapy Resistance in Colon Carcinoma Cells? Cells 2019; 8:cells8080797. [PMID: 31366165 PMCID: PMC6721497 DOI: 10.3390/cells8080797] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2019] [Revised: 07/26/2019] [Accepted: 07/29/2019] [Indexed: 12/28/2022] Open
Abstract
An increased expression and cytoplasmic abundance of the ubiquitous RNA binding protein human antigen R (HuR) is critically implicated in the dysregulated control of post- transcriptional gene expression during colorectal cancer development and is frequently associated with a high grade of malignancy and therapy resistance. Regardless of the fact that HuR elicits a broad cell survival program by increasing the stability of mRNAs coding for prominent anti-apoptotic factors, recent data suggest that HuR is critically involved in the regulation of translation, particularly, in the internal ribosome entry site (IRES) controlled translation of cell death regulatory proteins. Accordingly, data from human colon carcinoma cells revealed that HuR maintains constitutively reduced protein and activity levels of caspase-2 through negative interference with IRES-mediated translation. This review covers recent advances in the understanding of mechanisms underlying HuR's modulatory activity on IRES-triggered translation. With respect to the unique regulatory features of caspase-2 and its multiple roles (e.g., in DNA-damage-induced apoptosis, cell cycle regulation and maintenance of genomic stability), the pathophysiological consequences of negative caspase-2 regulation by HuR and its impact on therapy resistance of colorectal cancers will be discussed in detail. The negative HuR-caspase-2 axis may offer a novel target for tumor sensitizing therapies.
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Díaz-Muñoz MD, Turner M. Uncovering the Role of RNA-Binding Proteins in Gene Expression in the Immune System. Front Immunol 2018; 9:1094. [PMID: 29875770 PMCID: PMC5974052 DOI: 10.3389/fimmu.2018.01094] [Citation(s) in RCA: 51] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2018] [Accepted: 05/02/2018] [Indexed: 12/29/2022] Open
Abstract
Fighting external pathogens requires an ever-changing immune system that relies on tight regulation of gene expression. Transcriptional control is the first step to build efficient responses while preventing immunodeficiencies and autoimmunity. Post-transcriptional regulation of RNA editing, location, stability, and translation are the other key steps for final gene expression, and they are all controlled by RNA-binding proteins (RBPs). Nowadays we have a deep understanding of how transcription factors control the immune system but recent evidences suggest that post-transcriptional regulation by RBPs is equally important for both development and activation of immune responses. Here, we review current knowledge about how post-transcriptional control by RBPs shapes our immune system and discuss the perspective of RBPs being the key players of a hidden immune cell epitranscriptome.
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Affiliation(s)
- Manuel D Díaz-Muñoz
- Centre de Physiopathologie Toulouse-Purpan, INSERM UMR1043/CNRS U5282, Toulouse, France
| | - Martin Turner
- Laboratory of Lymphocyte Signalling and Development, The Babraham Institute, Cambridge, United Kingdom
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18
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Alfano L, Costa C, Caporaso A, Antonini D, Giordano A, Pentimalli F. HUR protects NONO from degradation by mir320, which is induced by p53 upon UV irradiation. Oncotarget 2018; 7:78127-78139. [PMID: 27816966 PMCID: PMC5363649 DOI: 10.18632/oncotarget.13002] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2016] [Accepted: 10/12/2016] [Indexed: 12/13/2022] Open
Abstract
UV radiations challenge genomic stability and are a recognized cancer risk factor. We previously found that the RNA-binding protein NONO regulates the intra-S phase checkpoint and its silencing impaired HeLa and melanoma cell response to UV-induced DNA damage. Here we investigated the mechanisms underlying NONO regulation upon UVC treatment. We found that UVC rays induce the expression of mir320a, which can indeed target NONO. However, despite mir320a induction, NONO mRNA and protein expression are not affected by UVC. We found through RNA immunoprecipitation that UVC rays induce the ubiquitous RNA-binding protein HUR to bind NONO 5′UTR in a site overlapping mir320a binding site. Both HUR silencing and its pharmacological inhibition induced NONO downregulation following UVC exposure, whereas concomitant mir320a silencing restored NONO stability. UVC-mediated mir320a upregulation is triggered by p53 binding to its promoter, which lies within a region marked by H3K4me3 and H3K27ac signals upon UVC treatment. Silencing mir320a sensitizes cells to DNA damage. Overall our findings reveal a new mechanism whereby HUR protects NONO from mir320-mediated degradation upon UVC exposure and identify a new component within the complex network of players underlying the DNA damage response adding mir320a to the list of p53-regulated targets upon genotoxic stress.
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Affiliation(s)
- Luigi Alfano
- Oncology Research Center of Mercogliano (CROM), Istituto Nazionale Per Lo Studio E La Cura Dei Tumori "Fondazione Giovanni Pascale", IRCCS, Naples, 80131, Italy
| | - Caterina Costa
- Oncology Research Center of Mercogliano (CROM), Istituto Nazionale Per Lo Studio E La Cura Dei Tumori "Fondazione Giovanni Pascale", IRCCS, Naples, 80131, Italy
| | - Antonella Caporaso
- Department of Medicine, Surgery and Neuroscience, University of Siena and Istituto Toscano Tumori (ITT), Siena, 53100, Italy
| | | | - Antonio Giordano
- Department of Medicine, Surgery and Neuroscience, University of Siena and Istituto Toscano Tumori (ITT), Siena, 53100, Italy.,Sbarro Institute for Cancer Research and Molecular Medicine, Center for Biotechnology, College of Science and Technology, Temple University, Philadelphia PA, 19122, USA
| | - Francesca Pentimalli
- Oncology Research Center of Mercogliano (CROM), Istituto Nazionale Per Lo Studio E La Cura Dei Tumori "Fondazione Giovanni Pascale", IRCCS, Naples, 80131, Italy.,Sbarro Institute for Cancer Research and Molecular Medicine, Center for Biotechnology, College of Science and Technology, Temple University, Philadelphia PA, 19122, USA
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Transcriptional and post-transcriptional regulation of the ionizing radiation response by ATM and p53. Sci Rep 2017; 7:43598. [PMID: 28256581 PMCID: PMC5335570 DOI: 10.1038/srep43598] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2016] [Accepted: 01/25/2017] [Indexed: 12/19/2022] Open
Abstract
In response to ionizing radiation (IR), cells activate a DNA damage response (DDR) pathway to re-program gene expression. Previous studies using total cellular RNA analyses have shown that the stress kinase ATM and the transcription factor p53 are integral components required for induction of IR-induced gene expression. These studies did not distinguish between changes in RNA synthesis and RNA turnover and did not address the role of enhancer elements in DDR-mediated transcriptional regulation. To determine the contribution of synthesis and degradation of RNA and monitor the activity of enhancer elements following exposure to IR, we used the recently developed Bru-seq, BruChase-seq and BruUV-seq techniques. Our results show that ATM and p53 regulate both RNA synthesis and stability as well as enhancer element activity following exposure to IR. Importantly, many genes in the p53-signaling pathway were coordinately up-regulated by both increased synthesis and RNA stability while down-regulated genes were suppressed either by reduced synthesis or stability. Our study is the first of its kind that independently assessed the effects of ionizing radiation on transcription and post-transcriptional regulation in normal human cells.
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Wamsley JJ, Issaeva N, An H, Lu X, Donehower LA, Yarbrough WG. LZAP is a novel Wip1 binding partner and positive regulator of its phosphatase activity in vitro. Cell Cycle 2016; 16:213-223. [PMID: 28027003 DOI: 10.1080/15384101.2016.1261767] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
The phosphatase Wip1 attenuates the DNA damage response (DDR) by removing phosphorylation marks from a number of DDR proteins (p53, MDM2, Chk1/2, p38). Wip1 also dephosphorylates and inactivates RelA. Notably, LZAP, a putative tumor suppressor, has been linked to dephosphorylation of several of these substrates, including RelA, p38, Chk1, and Chk2. LZAP has no known catalytic activity or functional motifs, suggesting that it exerts its effects through interaction with other proteins. Here we show that LZAP binds Wip1 and stimulates its phosphatase activity. LZAP had been previously shown to bind many Wip1 substrates (RelA, p38, Chk1/2), and our results show that LZAP also binds the previously identified Wip1 substrate, MDM2. This work identifies 2 novel Wip1 substrates, ERK1 and HuR, and demonstrates that HuR is a binding partner of LZAP. Pleasingly, LZAP potentiated Wip1 catalytic activity toward each substrate tested, regardless of whether full-length substrates or phosphopeptides were utilized. Since this effect was observed on ERK1, which does not bind LZAP, as well as for each of 7 peptides tested, we hypothesize that LZAP binding to the substrate is not required for this effect and that LZAP directly binds Wip1 to augment its phosphatase activity.
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Affiliation(s)
- J Jacob Wamsley
- a Department of Surgery, Division of Otolaryngology , Yale University , New Haven , CT , USA
| | - Natalia Issaeva
- a Department of Surgery, Division of Otolaryngology , Yale University , New Haven , CT , USA.,b Yale Cancer Center, Yale University , New Haven , CT , USA
| | - Hanbing An
- c Department of Surgery , Vanderbilt University , Nashville , TN , USA
| | - Xinyuan Lu
- d Department of Medicine , University of California San Francisco , San Francisco , CA , USA
| | - Lawrence A Donehower
- e Department of Molecular Virology and Microbiology , Baylor College of Medicine , Houston , TX , USA
| | - Wendell G Yarbrough
- a Department of Surgery, Division of Otolaryngology , Yale University , New Haven , CT , USA.,b Yale Cancer Center, Yale University , New Haven , CT , USA.,f Department of Pathology , Yale University , New Haven , CT , USA
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Mueller M, Oppliger B, Joerger-Messerli M, Reinhart U, Barnea E, Paidas M, Kramer BW, Surbek DV, Schoeberlein A. Wharton's Jelly Mesenchymal Stem Cells Protect the Immature Brain in Rats and Modulate Cell Fate. Stem Cells Dev 2016; 26:239-248. [PMID: 27842457 DOI: 10.1089/scd.2016.0108] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
The development of a mammalian brain is a complex and long-lasting process. Not surprisingly, preterm birth is the leading cause of death in newborns and children. Advances in perinatal care reduced mortality, but morbidity still represents a major burden. New therapeutic approaches are thus desperately needed. Given that mesenchymal stem/stromal cells (MSCs) emerged as a promising candidate for cell therapy, we transplanted MSCs derived from the Wharton's Jelly (WJ-MSCs) to reduce the burden of immature brain injury in a murine animal model. WJ-MSCs transplantation resulted in protective activity characterized by reduced myelin loss and astroglial activation. WJ-MSCs improved locomotor behavior as well. To address the underlying mechanisms, we tested the key regulators of responses to DNA-damaging agents, such as cyclic AMP-dependent protein kinase/calcium-dependent protein kinase (PKA/PKC), cyclin-dependent kinase (CDK), ataxia-telangiectasia-mutated/ATM- and Rad3-related (ATM/ATR) substrates, protein kinase B (Akt), and 14-3-3 binding protein partners. We characterized WJ-MSCs using a specific profiler polymerase chain reaction array. We provide evidence that WJ-MSCs target pivotal regulators of the cell fate such as CDK/14-3-3/Akt signaling. We identified leukemia inhibitory factor as a potential candidate of WJ-MSCs' induced modifications as well. We hypothesize that WJ-MSCs may exert adaptive responses depending on the type of injury they are facing, making them prominent candidates for cell therapy in perinatal injuries.
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Affiliation(s)
- Martin Mueller
- 1 Department of Clinical Research, University of Bern , Bern, Switzerland .,2 Department of Obstetrics and Gynecology, University of Bern , Bern, Switzerland .,3 Department of Obstetrics, Gynecology, and Reproductive Sciences, Yale University School of Medicine , New Haven, Connecticut
| | - Byron Oppliger
- 1 Department of Clinical Research, University of Bern , Bern, Switzerland .,2 Department of Obstetrics and Gynecology, University of Bern , Bern, Switzerland
| | - Marianne Joerger-Messerli
- 1 Department of Clinical Research, University of Bern , Bern, Switzerland .,2 Department of Obstetrics and Gynecology, University of Bern , Bern, Switzerland
| | - Ursula Reinhart
- 1 Department of Clinical Research, University of Bern , Bern, Switzerland .,2 Department of Obstetrics and Gynecology, University of Bern , Bern, Switzerland
| | - Eytan Barnea
- 4 Society for the Investigation of Early Pregnancy and BioIncept LLC , Cherry Hill, New Jersey
| | - Michael Paidas
- 3 Department of Obstetrics, Gynecology, and Reproductive Sciences, Yale University School of Medicine , New Haven, Connecticut
| | - Boris W Kramer
- 5 Department of Pediatrics, Maastricht University Medical Center (MUMC) , Maastricht, the Netherlands .,6 Division Neuroscience, Department of Neuropsychology, School of Mental Health and Neuroscience (MHeNS), Maastricht University , Maastricht, the Netherlands
| | - Daniel V Surbek
- 1 Department of Clinical Research, University of Bern , Bern, Switzerland .,2 Department of Obstetrics and Gynecology, University of Bern , Bern, Switzerland
| | - Andreina Schoeberlein
- 1 Department of Clinical Research, University of Bern , Bern, Switzerland .,2 Department of Obstetrics and Gynecology, University of Bern , Bern, Switzerland
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Wahba A, Lehman SL, Tofilon PJ. Radiation-induced translational control of gene expression. TRANSLATION (AUSTIN, TEX.) 2016; 5:e1265703. [PMID: 28702276 PMCID: PMC5501380 DOI: 10.1080/21690731.2016.1265703] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/10/2016] [Revised: 11/17/2016] [Accepted: 11/23/2016] [Indexed: 10/20/2022]
Abstract
Radiation-induced gene expression has long been hypothesized to protect against cell death. Defining this process would provide not only insight into the mechanisms mediating cell survival after radiation exposure, but also a novel source of targets for radiosensitization. However, whereas the radiation-induced gene expression profiles using total cellular mRNA have been generated for cell lines as well as normal tissues, with few exception, the changes in mRNA do not correlate with changes in the corresponding protein. The traditional approach to profiling gene expression, i.e., using total cellular RNA, does not take into account posttranscriptional regulation. In this review, we describe the use of gene expression profiling of polysome-bound RNA to establish that radiation modifies gene expression via translational control. Because changes in polysome-bound mRNA correlate with changes in protein, analysis of the translational profiles provides a unique data set for investigating the mechanisms mediating cellular radioresponse.
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Affiliation(s)
- Amy Wahba
- Radiation Oncology Branch, National Cancer Institute, Bethesda, MD, USA
| | - Stacey L. Lehman
- Radiation Oncology Branch, National Cancer Institute, Bethesda, MD, USA
| | - Philip J. Tofilon
- Radiation Oncology Branch, National Cancer Institute, Bethesda, MD, USA
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23
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Guo J, Lv J, Chang S, Chen Z, Lu W, Xu C, Liu M, Pang X. Inhibiting cytoplasmic accumulation of HuR synergizes genotoxic agents in urothelial carcinoma of the bladder. Oncotarget 2016; 7:45249-45262. [PMID: 27303922 PMCID: PMC5216720 DOI: 10.18632/oncotarget.9932] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2016] [Accepted: 05/28/2016] [Indexed: 11/25/2022] Open
Abstract
HuR, an RNA-binding protein, post-transcriptionally regulates nearly 4% of encoding proteins implicated in cell survival. Here we show that HuR is required for the efficacy of chemotherapies in urothelial carcinoma of the bladder. We identify pyrvinium pamoate, an FDA-approved anthelminthic drug, as a novel HuR inhibitor that dose-dependently inhibited cytoplasmic accumulation of HuR. Combining pyrvinium pamoate with chemotherapeutic agents (e.g. cisplatin, doxorubicin, vincristine and oxaliplatin) not only led to enhanced cytotoxicity in bladder cancer cells but also synergistically suppressed the growth of patient-derived bladder tumor xenografts in mice (P < 0.001). Mechanistically, pyrvinium pamoate promoted nuclear import of HuR by activating the AMP-activated kinase/importin α1 cascade and blocked HuR nucleo-cytoplasmic translocation by inhibiting the checkpoint kinase1/cyclin-dependent kinase 1 pathway. Notably, pyrvinium pamoate-additive treatment increased DNA double-strand breaks as indicated by elevated γH2AX expression, suggesting an involvement of DNA damage response. We further found that pyrvinium pamoate dramatically downregulated several key DNA repair genes in genotoxically-stressed cells, including DNA ligase IV and BRCA2, leading to unbearable genomic instability and cell death. Collectively, our findings are the first to characterize a clinical HuR inhibitor and provide a novel therapeutically tractable strategy by targeting cytoplasmic translocation of HuR for treatment of urothelial carcinoma of the bladder.
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Affiliation(s)
- Jiawei Guo
- Shanghai Key Laboratory of Regulatory Biology, Institute of Biomedical Sciences and School of Life Sciences, East China Normal University, Shanghai 200241, China
| | - Jing Lv
- Shanghai Key Laboratory of Regulatory Biology, Institute of Biomedical Sciences and School of Life Sciences, East China Normal University, Shanghai 200241, China
| | - Siyu Chang
- Shanghai Key Laboratory of Regulatory Biology, Institute of Biomedical Sciences and School of Life Sciences, East China Normal University, Shanghai 200241, China
| | - Zhi Chen
- Shanghai Key Laboratory of Regulatory Biology, Institute of Biomedical Sciences and School of Life Sciences, East China Normal University, Shanghai 200241, China
| | - Weiqiang Lu
- Shanghai Key Laboratory of Regulatory Biology, Institute of Biomedical Sciences and School of Life Sciences, East China Normal University, Shanghai 200241, China
| | - Chuanliang Xu
- Department of Urology, Shanghai Changhai Hospital, Second Military Medical University, Shanghai 200433, China
| | - Mingyao Liu
- Shanghai Key Laboratory of Regulatory Biology, Institute of Biomedical Sciences and School of Life Sciences, East China Normal University, Shanghai 200241, China
- Institute of Biosciences and Technology, Department of Molecular and Cellular Medicine, Texas A&M University Health Science Center, Houston, Texas 77030, USA
| | - Xiufeng Pang
- Shanghai Key Laboratory of Regulatory Biology, Institute of Biomedical Sciences and School of Life Sciences, East China Normal University, Shanghai 200241, China
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24
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Mukherjee J, Ohba S, See WL, Phillips JJ, Molinaro AM, Pieper RO. PKM2 uses control of HuR localization to regulate p27 and cell cycle progression in human glioblastoma cells. Int J Cancer 2016; 139:99-111. [PMID: 26874904 PMCID: PMC6615049 DOI: 10.1002/ijc.30041] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2015] [Revised: 01/27/2016] [Accepted: 02/01/2016] [Indexed: 01/01/2023]
Abstract
The M2 isoform of pyruvate kinase (PK) is upregulated in most cancers including glioblastoma. Although PKM2 has been reported to use dual kinase activities to regulate cell growth, it also interacts with phosphotyrosine (pY)-containing peptides independently of its kinase activity. The potential for PKM2 to use the binding of pY-containing proteins to control tumor growth has not been fully examined. We here describe a novel mechanism by which PKM2 interacts in the nucleus with the RNA binding protein HuR to regulate HuR sub-cellular localization, p27 levels, cell cycle progression and glioma cell growth. Suppression of PKM2 in U87, T98G and LN319 glioma cells resulted in increased p27 levels, defects in entry into mitosis, increased centrosome number, and decreased cell growth. These effects could be reversed by shRNA targeting p27. The increased levels of p27 in PKM2 knock-down cells were caused by a loss of the nuclear interaction between PKM2 and HuR, and a subsequent cytoplasmic re-distribution of HuR, which in turn led to increased cap-independent p27 mRNA translation. Consistent with these results, the alterations in p27 mRNA translation, cell cycle progression and cell growth caused by PKM2 suppression could be reversed in vitro and in vivo by suppression of HuR or p27 levels, or by introduction of forms of PKM2 that could bind pY, regardless of their kinase activity. These results define a novel mechanism by which PKM2 regulates glioma cell growth, and also define a novel set of potential therapeutic targets along the PKM2-HuR-p27 pathway.
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Affiliation(s)
- Joydeep Mukherjee
- The Department of Neurological Surgery and the Brain Tumor Research Center, Helen Diller Family Comprehensive Cancer Center, University of California-San Francisco, San Francisco, CA, 94158
| | - Shigeo Ohba
- The Department of Neurological Surgery and the Brain Tumor Research Center, Helen Diller Family Comprehensive Cancer Center, University of California-San Francisco, San Francisco, CA, 94158
| | - Wendy L See
- The Department of Neurological Surgery and the Brain Tumor Research Center, Helen Diller Family Comprehensive Cancer Center, University of California-San Francisco, San Francisco, CA, 94158
| | - Joanna J Phillips
- The Department of Neurological Surgery and the Brain Tumor Research Center, Helen Diller Family Comprehensive Cancer Center, University of California-San Francisco, San Francisco, CA, 94158
| | - Annette M Molinaro
- The Department of Neurological Surgery and the Brain Tumor Research Center, Helen Diller Family Comprehensive Cancer Center, University of California-San Francisco, San Francisco, CA, 94158
| | - Russell O Pieper
- The Department of Neurological Surgery and the Brain Tumor Research Center, Helen Diller Family Comprehensive Cancer Center, University of California-San Francisco, San Francisco, CA, 94158
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25
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Leijon H, Salmenkivi K, Heiskanen I, Hagström J, Louhimo J, Heikkilä P, Ristimäki A, Paavonen T, Metso S, Mäenpää H, Haglund C, Arola J. HuR in pheochromocytomas and paragangliomas - overexpression in verified malignant tumors. APMIS 2016; 124:757-63. [DOI: 10.1111/apm.12571] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2016] [Accepted: 05/23/2016] [Indexed: 12/12/2022]
Affiliation(s)
- Helena Leijon
- Department of Pathology; University of Helsinki and Helsinki University Hospital; Helsinki Finland
| | - Kaisa Salmenkivi
- Department of Pathology; University of Helsinki and Helsinki University Hospital; Helsinki Finland
| | - Ilkka Heiskanen
- Department of Surgery; University of Helsinki and Helsinki University Hospital; Helsinki Finland
| | - Jaana Hagström
- Department of Pathology; University of Helsinki and Helsinki University Hospital; Helsinki Finland
- Department of Oral Pathology; University of Helsinki and Helsinki University Hospital; Helsinki Finland
| | - Johanna Louhimo
- Department of Surgery; University of Helsinki and Helsinki University Hospital; Helsinki Finland
| | - Päivi Heikkilä
- Department of Pathology; University of Helsinki and Helsinki University Hospital; Helsinki Finland
| | - Ari Ristimäki
- Department of Pathology; University of Helsinki and Helsinki University Hospital; Helsinki Finland
- Genome-Scale Biology; Research Programs Unit; University of Helsinki; Helsinki Finland
| | - Timo Paavonen
- Department of Pathology; Fimlab Laboratories; Tampere University Hospital; Tampere Finland
- School of Medicine; University of Tampere; Tampere Finland
| | - Saara Metso
- Department of Internal Medicine; Tampere University Hospital; Tampere Finland
- School of Medicine; University of Tampere; Tampere Finland
| | - Hanna Mäenpää
- Department of Oncology; University of Helsinki and Helsinki University Hospital; Helsinki Finland
| | - Caj Haglund
- Department of Surgery; University of Helsinki and Helsinki University Hospital; Helsinki Finland
- Translational Cancer Biology; Research Programs Unit; University of Helsinki; Helsinki Finland
| | - Johanna Arola
- Department of Pathology; University of Helsinki and Helsinki University Hospital; Helsinki Finland
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26
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Vlasova-St Louis I, Bohjanen PR. Feedback Regulation of Kinase Signaling Pathways by AREs and GREs. Cells 2016; 5:cells5010004. [PMID: 26821046 PMCID: PMC4810089 DOI: 10.3390/cells5010004] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2015] [Revised: 01/20/2016] [Accepted: 01/20/2016] [Indexed: 12/18/2022] Open
Abstract
In response to environmental signals, kinases phosphorylate numerous proteins, including RNA-binding proteins such as the AU-rich element (ARE) binding proteins, and the GU-rich element (GRE) binding proteins. Posttranslational modifications of these proteins lead to a significant changes in the abundance of target mRNAs, and affect gene expression during cellular activation, proliferation, and stress responses. In this review, we summarize the effect of phosphorylation on the function of ARE-binding proteins ZFP36 and ELAVL1 and the GRE-binding protein CELF1. The networks of target mRNAs that these proteins bind and regulate include transcripts encoding kinases and kinase signaling pathways (KSP) components. Thus, kinase signaling pathways are involved in feedback regulation, whereby kinases regulate RNA-binding proteins that subsequently regulate mRNA stability of ARE- or GRE-containing transcripts that encode components of KSP.
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Affiliation(s)
- Irina Vlasova-St Louis
- Department of Medicine, University of Minnesota, Minneapolis, MN 55455, USA.
- Department of Microbiology, University of Minnesota, Minneapolis, MN 55455, USA.
| | - Paul R Bohjanen
- Department of Medicine, University of Minnesota, Minneapolis, MN 55455, USA.
- Center for Infectious Diseases and Microbiology Translational Research, University of Minnesota, Minneapolis, MN 55455, USA.
- Department of Microbiology, University of Minnesota, Minneapolis, MN 55455, USA.
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27
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Shkreta L, Chabot B. The RNA Splicing Response to DNA Damage. Biomolecules 2015; 5:2935-77. [PMID: 26529031 PMCID: PMC4693264 DOI: 10.3390/biom5042935] [Citation(s) in RCA: 100] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2015] [Revised: 09/20/2015] [Accepted: 10/16/2015] [Indexed: 12/29/2022] Open
Abstract
The number of factors known to participate in the DNA damage response (DDR) has expanded considerably in recent years to include splicing and alternative splicing factors. While the binding of splicing proteins and ribonucleoprotein complexes to nascent transcripts prevents genomic instability by deterring the formation of RNA/DNA duplexes, splicing factors are also recruited to, or removed from, sites of DNA damage. The first steps of the DDR promote the post-translational modification of splicing factors to affect their localization and activity, while more downstream DDR events alter their expression. Although descriptions of molecular mechanisms remain limited, an emerging trend is that DNA damage disrupts the coupling of constitutive and alternative splicing with the transcription of genes involved in DNA repair, cell-cycle control and apoptosis. A better understanding of how changes in splice site selection are integrated into the DDR may provide new avenues to combat cancer and delay aging.
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Affiliation(s)
- Lulzim Shkreta
- Microbiologie et d'Infectiologie, Faculté de Médecine et des Sciences de la Santé, Université de Sherbrooke, Sherbrooke, QC J1E 4K8, Canada.
| | - Benoit Chabot
- Microbiologie et d'Infectiologie, Faculté de Médecine et des Sciences de la Santé, Université de Sherbrooke, Sherbrooke, QC J1E 4K8, Canada.
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28
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Osera C, Martindale JL, Amadio M, Kim J, Yang X, Moad CA, Indig FE, Govoni S, Abdelmohsen K, Gorospe M, Pascale A. Induction of VEGFA mRNA translation by CoCl2 mediated by HuR. RNA Biol 2015; 12:1121-30. [PMID: 26325091 DOI: 10.1080/15476286.2015.1085276] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Vascular endothelial growth factor (VEGF) A is a master regulator of neovascularization and angiogenesis. VEGFA is potently induced by hypoxia and by pathological conditions including diabetic retinopathy and tumorigenesis. Fine-tuning of VEGFA expression by different stimuli is important for maintaining tissue vascularization and organ homeostasis. Here, we tested the effect of the hypoxia mimetic cobalt chloride (CoCl2) on VEGFA expression in human cervical carcinoma HeLa cells. We found that CoCl2 increased the levels of VEGFA mRNA and VEGFA protein without affecting VEGFA mRNA stability. Biotin pulldown analysis to capture the RNA-binding proteins (RBPs) bound to VEGFA mRNA followed by mass spectrometry analysis revealed that the RBP HuR [human antigen R, a member of the embryonic lethal abnormal vision (ELAV) family of proteins], interacts with VEGFA mRNA. VEGFA mRNA-tagging experiments showed that exposure to CoCl2 increases the interaction of HuR with VEGFA mRNA and promoted the colocalization of HuR and the distal part of the VEGFA 3'-untranslated region (UTR) in the cytoplasm. We propose that under hypoxia-like conditions, HuR enhances VEGFA mRNA translation.
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Affiliation(s)
- Cecilia Osera
- a Laboratory of Genetics, National Institute on Aging-Intramural Research Program, NIH ; Baltimore , MD USA.,b Laboratory of Cellular and Molecular Neuropharmacology, Department of Drug Sciences, Section of Pharmacology, University of Pavia ; Pavia , Italy
| | - Jennifer L Martindale
- a Laboratory of Genetics, National Institute on Aging-Intramural Research Program, NIH ; Baltimore , MD USA
| | - Marialaura Amadio
- b Laboratory of Cellular and Molecular Neuropharmacology, Department of Drug Sciences, Section of Pharmacology, University of Pavia ; Pavia , Italy
| | - Jiyoung Kim
- a Laboratory of Genetics, National Institute on Aging-Intramural Research Program, NIH ; Baltimore , MD USA
| | - Xiaoling Yang
- a Laboratory of Genetics, National Institute on Aging-Intramural Research Program, NIH ; Baltimore , MD USA
| | - Christopher A Moad
- a Laboratory of Genetics, National Institute on Aging-Intramural Research Program, NIH ; Baltimore , MD USA
| | - Fred E Indig
- a Laboratory of Genetics, National Institute on Aging-Intramural Research Program, NIH ; Baltimore , MD USA
| | - Stefano Govoni
- b Laboratory of Cellular and Molecular Neuropharmacology, Department of Drug Sciences, Section of Pharmacology, University of Pavia ; Pavia , Italy
| | - Kotb Abdelmohsen
- a Laboratory of Genetics, National Institute on Aging-Intramural Research Program, NIH ; Baltimore , MD USA
| | - Myriam Gorospe
- a Laboratory of Genetics, National Institute on Aging-Intramural Research Program, NIH ; Baltimore , MD USA
| | - Alessia Pascale
- b Laboratory of Cellular and Molecular Neuropharmacology, Department of Drug Sciences, Section of Pharmacology, University of Pavia ; Pavia , Italy
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29
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DeMicco A, Naradikian MS, Sindhava VJ, Yoon JH, Gorospe M, Wertheim GB, Cancro MP, Bassing CH. B Cell-Intrinsic Expression of the HuR RNA-Binding Protein Is Required for the T Cell-Dependent Immune Response In Vivo. THE JOURNAL OF IMMUNOLOGY 2015; 195:3449-62. [PMID: 26320247 DOI: 10.4049/jimmunol.1500512] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/03/2015] [Accepted: 08/03/2015] [Indexed: 11/19/2022]
Abstract
The HuR RNA-binding protein posttranscriptionally controls expression of genes involved in cellular survival, proliferation, and differentiation. To determine roles of HuR in B cell development and function, we analyzed mice with B lineage-specific deletion of the HuR gene. These HuRΔ/Δ mice have reduced numbers of immature bone marrow and mature splenic B cells, with only the former rescued by p53 inactivation, indicating that HuR supports B lineage cells through developmental stage-specific mechanisms. Upon in vitro activation, HuRΔ/Δ B cells have a mild proliferation defect and impaired ability to produce mRNAs that encode IgH chains of secreted Abs, but no deficiencies in survival, isotype switching, or expression of germinal center (GC) markers. In contrast, HuRΔ/Δ mice have minimal serum titers of all Ab isotypes, decreased numbers of GC and plasma B cells, and few peritoneal B-1 B cells. Moreover, HuRΔ/Δ mice have severely decreased GCs, T follicular helper cells, and high-affinity Abs after immunization with a T cell-dependent Ag. This failure of HuRΔ/Δ mice to mount a T cell-dependent Ab response contrasts with the ability of HuRΔ/Δ B cells to become GC-like in vitro, indicating that HuR is essential for aspects of B cell activation unique to the in vivo environment. Consistent with this notion, we find in vitro stimulated HuRΔ/Δ B cells exhibit modestly reduced surface expression of costimulatory molecules whose expression is similarly decreased in humans with common variable immunodeficiency. HuRΔ/Δ mice provide a model to identify B cell-intrinsic factors that promote T cell-dependent immune responses in vivo.
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Affiliation(s)
- Amy DeMicco
- Division of Cancer Pathobiology, Department of Pathology and Laboratory Medicine, Center for Childhood Cancer Research, Children's Hospital of Philadelphia, Philadelphia, PA 19104; Cell and Molecular Biology Graduate Group, Department of Pathology and Laboratory Medicine, Abramson Family Cancer Research Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104
| | - Martin S Naradikian
- Immunology Graduate Group, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104; Department of Pathology and Laboratory Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104
| | - Vishal J Sindhava
- Department of Pathology and Laboratory Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104
| | - Je-Hyun Yoon
- Laboratory of Genetics, National Institute on Aging-Intramural Research Program, National Institutes of Health, Baltimore, MD 21224; and
| | - Myriam Gorospe
- Laboratory of Genetics, National Institute on Aging-Intramural Research Program, National Institutes of Health, Baltimore, MD 21224; and
| | - Gerald B Wertheim
- Department of Pathology and Laboratory Medicine, Children's Hospital of Philadelphia, Philadelphia, PA 19104
| | - Michael P Cancro
- Immunology Graduate Group, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104; Department of Pathology and Laboratory Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104
| | - Craig H Bassing
- Division of Cancer Pathobiology, Department of Pathology and Laboratory Medicine, Center for Childhood Cancer Research, Children's Hospital of Philadelphia, Philadelphia, PA 19104; Cell and Molecular Biology Graduate Group, Department of Pathology and Laboratory Medicine, Abramson Family Cancer Research Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104;
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30
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Hausburg MA, Doles JD, Clement SL, Cadwallader AB, Hall MN, Blackshear PJ, Lykke-Andersen J, Olwin BB. Post-transcriptional regulation of satellite cell quiescence by TTP-mediated mRNA decay. eLife 2015; 4:e03390. [PMID: 25815583 PMCID: PMC4415119 DOI: 10.7554/elife.03390] [Citation(s) in RCA: 102] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2014] [Accepted: 03/26/2015] [Indexed: 12/20/2022] Open
Abstract
Skeletal muscle satellite cells in their niche are quiescent and upon muscle injury, exit quiescence, proliferate to repair muscle tissue, and self-renew to replenish the satellite cell population. To understand the mechanisms involved in maintaining satellite cell quiescence, we identified gene transcripts that were differentially expressed during satellite cell activation following muscle injury. Transcripts encoding RNA binding proteins were among the most significantly changed and included the mRNA decay factor Tristetraprolin. Tristetraprolin promotes the decay of MyoD mRNA, which encodes a transcriptional regulator of myogenic commitment, via binding to the MyoD mRNA 3′ untranslated region. Upon satellite cell activation, p38α/β MAPK phosphorylates MAPKAP2 and inactivates Tristetraprolin, stabilizing MyoD mRNA. Satellite cell specific knockdown of Tristetraprolin precociously activates satellite cells in vivo, enabling MyoD accumulation, differentiation and cell fusion into myofibers. Regulation of mRNAs by Tristetraprolin appears to function as one of several critical post-transcriptional regulatory mechanisms controlling satellite cell homeostasis. DOI:http://dx.doi.org/10.7554/eLife.03390.001 When muscles are damaged, they can repair themselves to some extent by making new muscle cells. These develop from groups of cells called satellite cells, which are found near the surface of muscle fibers. Once the muscle is injured, the satellite cells are activated and can divide to form two cells with different properties. One remains a satellite cell, while the other forms a ‘myoblast’ that eventually fuses into a mature muscle fiber. Under normal conditions the satellite cells remain in a dormant state and do not divide, but it is not clear how they maintain this dormant state. To create a protein, the gene that encodes it is first ‘transcribed’ to produce a molecule called mRNA, which is then used as a template to build the protein. A protein called Tristetraprolin (TTP) can bind to mRNA molecules and cause them to break down or decay, and so TTP can prevent the mRNA from being used to make a protein. Hausburg, Doles et al. analyzed satellite cells from uninjured muscle and compared them with those from injured tissue. This revealed that when injured, the satellite cells reduced the abundance of several mRNAs, including TTP. Further investigation found that in satellite cells from uninjured tissue, TTP causes the decay of mRNA molecules that are used to produce a protein called MyoD. As MyoD helps the satellite cells to specialize, this decay therefore prevents the formation of myoblasts and keeps the satellite cells in a dormant state. In contrast, damage to the muscle tissue activates a signaling pathway that ultimately inactivates TTP. This enables more of the MyoD protein to be made and the myoblast population to expand. When Hausburg, Doles et al. experimentally reduced the levels of TTP inside satellite cells, the cells developed into myoblasts even when the tissue was uninjured. Thus, TTP is an important regulator that allows satellite cells to remain in a dormant state. In dormant adult stem cells, regulation of protein availability by RNA binding proteins, such as TTP, may co-ordinate rapid changes in metabolic state to promptly repair injured tissue. A major challenge will be to identify the group of proteins involved and determine the precise mechanisms involved in regulating their availability. DOI:http://dx.doi.org/10.7554/eLife.03390.002
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Affiliation(s)
- Melissa A Hausburg
- Department of Molecular, Cellular, and Developmental Biology, University of Colorado Boulder, Boulder, United States
| | - Jason D Doles
- Department of Molecular, Cellular, and Developmental Biology, University of Colorado Boulder, Boulder, United States
| | - Sandra L Clement
- Department of Molecular, Cellular, and Developmental Biology, University of Colorado Boulder, Boulder, United States
| | - Adam B Cadwallader
- Department of Molecular, Cellular, and Developmental Biology, University of Colorado Boulder, Boulder, United States
| | - Monica N Hall
- Department of Molecular, Cellular, and Developmental Biology, University of Colorado Boulder, Boulder, United States
| | - Perry J Blackshear
- Department of Molecular, Cellular, and Developmental Biology, University of Colorado Boulder, Boulder, United States
| | - Jens Lykke-Andersen
- Department of Molecular, Cellular, and Developmental Biology, University of Colorado Boulder, Boulder, United States
| | - Bradley B Olwin
- Department of Molecular, Cellular, and Developmental Biology, University of Colorado Boulder, Boulder, United States
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31
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Growth factor dependent regulation of centrosome function and genomic instability by HuR. Biomolecules 2015; 5:263-81. [PMID: 25803745 PMCID: PMC4384122 DOI: 10.3390/biom5010263] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2014] [Revised: 03/06/2015] [Accepted: 03/11/2015] [Indexed: 01/10/2023] Open
Abstract
The mRNA binding protein HuR is over expressed in cancer cells and contributes to disease progression through post-transcriptional regulation of mRNA. The regulation of HuR and how this relates to glioma is the focus of this report. SRC and c-Abl kinases regulate HuR sub-cellular trafficking and influence accumulation in the pericentriolar matrix (PCM) via a growth factor dependent signaling mechanism. Growth factor stimulation of glioma cell lines results in the associate of HuR with the PCM and amplification of centrosome number. This process is regulated by tyrosine phosphorylation of HuR and is abolished by mutating tyrosine residues. HuR is overexpressed in tumor samples from patients with glioblastoma and associated with a reduced survival. These findings suggest HuR plays a significant role in centrosome amplification and genomic instability, which contributes to a worse disease outcome.
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32
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Kotta-Loizou I, Giaginis C, Theocharis S. Clinical significance of HuR expression in human malignancy. Med Oncol 2014; 31:161. [PMID: 25112469 DOI: 10.1007/s12032-014-0161-y] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2014] [Accepted: 08/01/2014] [Indexed: 12/28/2022]
Abstract
Hu-antigen R (HuR) is an RNA-binding protein that regulates the stability, translation, and nucleus-to-cytoplasm translocation of target mRNAs. The aim of the present review was to summarize and present the currently available information in the English literature on HuR expression in various human tumors, verifying its possible clinical significance. HuR function is directly linked to its subcellular localization. In normal cells, HuR is mostly localized in the nucleus, while in malignant cells, an increase in cytoplasmic HuR levels has been noted, in both cell lines and tissue samples. Moreover, in malignancy, elevated HuR expression levels and cytoplasmic immunohistochemical pattern have been correlated with advanced clinicopathological parameters and altered expression levels of proteins implicated in neoplasia. Additionally, elevated HuR expression levels and mainly cytoplasmic immunohistochemical pattern were correlated with decreased patients' survival rate in various human tumors. HuR is a putative drug target for cancer therapy, since it is expressed ubiquitously in malignant clinical samples and has an apparently consistent role in tumor formation and progression.
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Affiliation(s)
- Ioly Kotta-Loizou
- Division of Cell and Molecular Biology, Imperial College London, London, UK
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33
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Nachmani D, Gutschner T, Reches A, Diederichs S, Mandelboim O. RNA-binding proteins regulate the expression of the immune activating ligand MICB. Nat Commun 2014; 5:4186. [PMID: 24924487 DOI: 10.1038/ncomms5186] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2014] [Accepted: 05/22/2014] [Indexed: 12/28/2022] Open
Abstract
The recognition of stress-induced ligands by the activating receptor NKG2D expressed on cytotoxic lymphocytes is crucial for the prevention and containment of various diseases and is also one of the best-studied examples of how danger is sensed by the immune system. Still, however, the mechanisms leading to the expression of the NKG2D ligands are far from being completely understood. Here, we use an unbiased and systematic RNA pull-down approach combined with mass spectrometry to identify six RNA-binding proteins (RBPs) that bind and regulate the expression of MICB, one of the major stress-induced ligands of NKG2D. We further demonstrate that at least two of the identified RBPs function during genotoxic stress. Our data provide insights into stress recognition and hopefully open new therapeutic venues.
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Affiliation(s)
- Daphna Nachmani
- The Lautenberg Center for General and Tumor Immunology, The BioMedical Research Institute Israel Canada of the Faculty of Medicine, The Hebrew University Hadassah Medical School, 91120 Jerusalem, Israel
| | - Tony Gutschner
- Helmholtz-University-Group "Molecular RNA Biology & Cancer", German Cancer Research Center DKFZ and Institute of Pathology, University Hospital Heidelberg, D-69120 Heidelberg, Germany
| | - Adi Reches
- The Lautenberg Center for General and Tumor Immunology, The BioMedical Research Institute Israel Canada of the Faculty of Medicine, The Hebrew University Hadassah Medical School, 91120 Jerusalem, Israel
| | - Sven Diederichs
- Helmholtz-University-Group "Molecular RNA Biology & Cancer", German Cancer Research Center DKFZ and Institute of Pathology, University Hospital Heidelberg, D-69120 Heidelberg, Germany
| | - Ofer Mandelboim
- The Lautenberg Center for General and Tumor Immunology, The BioMedical Research Institute Israel Canada of the Faculty of Medicine, The Hebrew University Hadassah Medical School, 91120 Jerusalem, Israel
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34
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Abstract
Unlike other Rho GTPases, RhoB is rapidly induced by DNA damage, and its expression level decreases during cancer progression. Because inefficient repair of DNA double-strand breaks (DSBs) can lead to cancer, we investigated whether camptothecin, an anticancer drug that produces DSBs, induces RhoB expression and examined its role in the camptothecin-induced DNA damage response. We show that in camptothecin-treated cells, DSBs induce RhoB expression by a mechanism that depends notably on Chk2 and its substrate HuR, which binds to RhoB mRNA and protects it against degradation. RhoB-deficient cells fail to dephosphorylate γH2AX following camptothecin removal and show reduced efficiency of DSB repair by homologous recombination. These cells also show decreased activity of protein phosphatase 2A (PP2A), a phosphatase for γH2AX and other DNA damage and repair proteins. Thus, we propose that DSBs activate a Chk2-HuR-RhoB pathway that promotes PP2A-mediated dephosphorylation of γH2AX and DSB repair. Finally, we show that RhoB-deficient cells accumulate endogenous γH2AX and chromosomal abnormalities, suggesting that RhoB loss increases DSB-mediated genomic instability and tumor progression.
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Lal S, Burkhart RA, Beeharry N, Bhattacharjee V, Londin ER, Cozzitorto JA, Romeo C, Jimbo M, Norris ZA, Yeo CJ, Sawicki JA, Winter JM, Rigoutsos I, Yen TJ, Brody JR. HuR posttranscriptionally regulates WEE1: implications for the DNA damage response in pancreatic cancer cells. Cancer Res 2014; 74:1128-40. [PMID: 24536047 DOI: 10.1158/0008-5472.can-13-1915] [Citation(s) in RCA: 78] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
HuR (ELAV1), an RNA-binding protein abundant in cancer cells, primarily resides in the nucleus, but under specific stress (e.g., gemcitabine), HuR translocates to the cytoplasm in which it tightly modulates the expression of mRNA survival cargo. Here, we demonstrate for the first time that stressing pancreatic ductal adenocarcinoma (PDA) cells by treatment with DNA-damaging anticancer agents (mitomycin C, oxaliplatin, cisplatin, carboplatin, and a PARP inhibitor) results in HuR's translocation from the nucleus to the cytoplasm. Importantly, silencing HuR in PDA cells sensitized the cells to these agents, whereas overexpressing HuR caused resistance. HuR's role in the efficacy of DNA-damaging agents in PDA cells was, in part, attributed to the acute upregulation of WEE1 by HuR. WEE1, a mitotic inhibitor kinase, regulates the DNA damage repair pathway, and therapeutic inhibition of WEE1 in combination with chemotherapy is currently in early phase trials for the treatment of cancer. We validate WEE1 as a HuR target in vitro and in vivo by demonstrating (i) direct binding of HuR to WEE1's mRNA (a discrete 56-bp region residing in the 3' untranslated region) and (ii) HuR siRNA silencing and overexpression directly affects the protein levels of WEE1, especially after DNA damage. HuR's positive regulation of WEE1 increases γ-H2AX levels, induces Cdk1 phosphorylation, and promotes cell-cycle arrest at the G2-M transition. We describe a novel mechanism that PDA cells use to protect against DNA damage in which HuR posttranscriptionally regulates the expression and downstream function of WEE1 upon exposure to DNA-damaging agents.
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Affiliation(s)
- Shruti Lal
- Authors' Affiliations: Department of Surgery, Division of Surgical Research, Jefferson Pancreas, Biliary and Related Cancer Center, Jefferson Medical College; Computational Medicine Center; Kimmel Cancer Center, Thomas Jefferson University; Fox Chase Cancer Center, Philadelphia; and Lankenau Institute for Medical Research, Wynnewood, Pennsylvania
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Dutertre M, Lambert S, Carreira A, Amor-Guéret M, Vagner S. DNA damage: RNA-binding proteins protect from near and far. Trends Biochem Sci 2014; 39:141-9. [DOI: 10.1016/j.tibs.2014.01.003] [Citation(s) in RCA: 76] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2013] [Revised: 01/20/2014] [Accepted: 01/20/2014] [Indexed: 12/14/2022]
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A recently evolved class of alternative 3'-terminal exons involved in cell cycle regulation by topoisomerase inhibitors. Nat Commun 2014; 5:3395. [PMID: 24577238 DOI: 10.1038/ncomms4395] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2013] [Accepted: 02/06/2014] [Indexed: 12/13/2022] Open
Abstract
Alternative 3'-terminal exons, which use intronic polyadenylation sites, are generally less conserved and expressed at lower levels than the last exon of genes. Here we discover a class of human genes, in which the last exon appeared recently during evolution, and the major gene product uses an alternative 3'-terminal exon corresponding to the ancestral last exon of the gene. This novel class of alternative 3'-terminal exons are downregulated on a large scale by doxorubicin, a cytostatic drug targeting topoisomerase II, and play a role in cell cycle regulation, including centromere-kinetochore assembly. The RNA-binding protein HuR/ELAVL1 is a major regulator of this specific set of alternative 3'-terminal exons. HuR binding to the alternative 3'-terminal exon in the pre-messenger RNA promotes its splicing, and is reduced by topoisomerase inhibitors. These findings provide new insights into the evolution, function and molecular regulation of alternative 3'-terminal exons.
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Al-Khalaf HH, Aboussekhra A. ATR controls the UV-related upregulation of the CDKN1A mRNA in a Cdk1/HuR-dependent manner. Mol Carcinog 2013; 53:979-87. [PMID: 23813879 DOI: 10.1002/mc.22066] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2013] [Revised: 05/13/2013] [Accepted: 05/31/2013] [Indexed: 11/10/2022]
Abstract
Ultraviolet (UV) light is a carcinogenic agent that upregulates the expression of several genes involved in various cellular processes, including cell cycle checkpoints and apoptosis. The universal cyclin-dependent kinase inhibitor p21(WAF1/Cip1) plays major roles in these processes, and the level of its corresponding message increases several times in response to UV-induced DNA damage. This upregulation is mainly posttranscriptional owing to HuR-dependent mRNA stabilization. Since the protein kinase Atr plays major roles during the cellular response to UV damage, we sought to investigate its possible implication in the stabilization of the p21(WAF1/Cip1) coding mRNA. We have shown that the UV-dependent accumulation of the CDKN1A mRNA is indeed under the control of the Atr protein kinase. Upon UV damage, Atr allows nuclear-cytoplasmic shuttling of the HuR protein, which binds the CDKN1A mRNA and reduces its turnover. This ATR-dependent effect is mediated through UV-related phosphorylation/inactivation of the Cdk1 protein kinase by Atr, which leads to the dissociation of HuR from Cdk1. Indeed, inhibition or shRNA specific knockdown of CDK1 in ATR-deficient cells enhanced the cytoplasmic level of HuR and restored the CDKN1A mRNA upregulation in response to UV damage. These results show that ATR stabilizes the CDKN1A message in response to UV damage through Cdk1-related cytoplasmic accumulation of HuR.
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Affiliation(s)
- Huda H Al-Khalaf
- Department of Molecular Oncology, King Faisal Specialist Hospital and Research Center, Riyadh, Kingdom of Saudi Arabia; The Joint Center for Genomics Research, King Abdulaziz City for Science and Technology, Riyadh, Kingdom of Saudi Arabia
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Impairment of FOS mRNA stabilization following translation arrest in granulocytes from myelodysplastic syndrome patients. PLoS One 2013; 8:e61107. [PMID: 23593403 PMCID: PMC3625160 DOI: 10.1371/journal.pone.0061107] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2012] [Accepted: 03/05/2013] [Indexed: 02/06/2023] Open
Abstract
Although quantitative and qualitative granulocyte defects have been described in myelodysplastic syndromes (MDS), the underlying molecular basis of granulocyte dysfunction in MDS is largely unknown. We recently found that FOS mRNA elevation under translation-inhibiting stimuli was significantly smaller in granulocytes from MDS patients than in healthy individuals. The aim of this study is to clarify the cause of the impaired FOS induction in MDS. We first examined the mechanisms of FOS mRNA elevation using granulocytes from healthy donors cultured with the translation inhibitor emetine. Emetine increased both transcription and mRNA stability of FOS. p38 MAPK inhibition abolished the emetine-induced increase of FOS transcription but did not affect FOS mRNA stabilization. The binding of an AU-rich element (ARE)-binding protein HuR to FOS mRNA containing an ARE in 3'UTR was increased by emetine, and the knockdown of HuR reduced the FOS mRNA stabilizing effect of emetine. We next compared the emetine-induced transcription and mRNA stabilization of FOS between MDS patients and healthy controls. Increased rates of FOS transcription by emetine were similar in MDS and controls. In the absence of emetine, FOS mRNA decayed to nearly 17% of initial levels in 45 min in both groups. In the presence of emetine, however, 76.7±19.8% of FOS mRNA remained after 45 min in healthy controls, versus 37.9±25.5% in MDS (P<0.01). To our knowledge, this is the first report demonstrating attenuation of stress-induced FOS mRNA stabilization in MDS granulocytes.
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Dassi E, Zuccotti P, Leo S, Provenzani A, Assfalg M, D’Onofrio M, Riva P, Quattrone A. Hyper conserved elements in vertebrate mRNA 3'-UTRs reveal a translational network of RNA-binding proteins controlled by HuR. Nucleic Acids Res 2013; 41:3201-16. [PMID: 23376935 PMCID: PMC3597683 DOI: 10.1093/nar/gkt017] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2012] [Revised: 12/20/2012] [Accepted: 12/26/2012] [Indexed: 02/06/2023] Open
Abstract
Little is known regarding the post-transcriptional networks that control gene expression in eukaryotes. Additionally, we still need to understand how these networks evolve, and the relative role played in them by their sequence-dependent regulatory factors, non-coding RNAs (ncRNAs) and RNA-binding proteins (RBPs). Here, we used an approach that relied on both phylogenetic sequence sharing and conservation in the whole mapped 3'-untranslated regions (3'-UTRs) of vertebrate species to gain knowledge on core post-transcriptional networks. The identified human hyper conserved elements (HCEs) were predicted to be preferred binding sites for RBPs and not for ncRNAs, namely microRNAs and long ncRNAs. We found that the HCE map identified a well-known network that post-transcriptionally regulates histone mRNAs. We were then able to discover and experimentally confirm a translational network composed of RNA Recognition Motif (RRM)-type RBP mRNAs that are positively controlled by HuR, another RRM-type RBP. HuR shows a preference for these RBP mRNAs bound in stem-loop motifs, confirming its role as a 'regulator of regulators'. Analysis of the transcriptome-wide HCE distribution revealed a profile of prevalently small clusters separated by unconserved intercluster RNA stretches, which predicts the formation of discrete small ribonucleoprotein complexes in the 3'-UTRs.
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Affiliation(s)
- Erik Dassi
- Laboratory of Translational Genomics, Centre for Integrative Biology, University of Trento, Trento, via delle Regole, 101 38123 Mattarello (TN) Italy, Department of Medical Biotechnology and Translational Medicine, University of Milan, Milan, via Viotti, 3/5 20133 Milano, Italy, Laboratory of Genomic Screening, Centre for Integrative Biology, University of Trento, Trento, via delle Regole, 101 38123 Mattarello (TN) Italy and Department of Biotechnology, University of Verona, Province of Verona, Ca' Vignal 1, Strada Le Grazie 15 37134 Verona, Italy
| | - Paola Zuccotti
- Laboratory of Translational Genomics, Centre for Integrative Biology, University of Trento, Trento, via delle Regole, 101 38123 Mattarello (TN) Italy, Department of Medical Biotechnology and Translational Medicine, University of Milan, Milan, via Viotti, 3/5 20133 Milano, Italy, Laboratory of Genomic Screening, Centre for Integrative Biology, University of Trento, Trento, via delle Regole, 101 38123 Mattarello (TN) Italy and Department of Biotechnology, University of Verona, Province of Verona, Ca' Vignal 1, Strada Le Grazie 15 37134 Verona, Italy
| | - Sara Leo
- Laboratory of Translational Genomics, Centre for Integrative Biology, University of Trento, Trento, via delle Regole, 101 38123 Mattarello (TN) Italy, Department of Medical Biotechnology and Translational Medicine, University of Milan, Milan, via Viotti, 3/5 20133 Milano, Italy, Laboratory of Genomic Screening, Centre for Integrative Biology, University of Trento, Trento, via delle Regole, 101 38123 Mattarello (TN) Italy and Department of Biotechnology, University of Verona, Province of Verona, Ca' Vignal 1, Strada Le Grazie 15 37134 Verona, Italy
| | - Alessandro Provenzani
- Laboratory of Translational Genomics, Centre for Integrative Biology, University of Trento, Trento, via delle Regole, 101 38123 Mattarello (TN) Italy, Department of Medical Biotechnology and Translational Medicine, University of Milan, Milan, via Viotti, 3/5 20133 Milano, Italy, Laboratory of Genomic Screening, Centre for Integrative Biology, University of Trento, Trento, via delle Regole, 101 38123 Mattarello (TN) Italy and Department of Biotechnology, University of Verona, Province of Verona, Ca' Vignal 1, Strada Le Grazie 15 37134 Verona, Italy
| | - Michael Assfalg
- Laboratory of Translational Genomics, Centre for Integrative Biology, University of Trento, Trento, via delle Regole, 101 38123 Mattarello (TN) Italy, Department of Medical Biotechnology and Translational Medicine, University of Milan, Milan, via Viotti, 3/5 20133 Milano, Italy, Laboratory of Genomic Screening, Centre for Integrative Biology, University of Trento, Trento, via delle Regole, 101 38123 Mattarello (TN) Italy and Department of Biotechnology, University of Verona, Province of Verona, Ca' Vignal 1, Strada Le Grazie 15 37134 Verona, Italy
| | - Mariapina D’Onofrio
- Laboratory of Translational Genomics, Centre for Integrative Biology, University of Trento, Trento, via delle Regole, 101 38123 Mattarello (TN) Italy, Department of Medical Biotechnology and Translational Medicine, University of Milan, Milan, via Viotti, 3/5 20133 Milano, Italy, Laboratory of Genomic Screening, Centre for Integrative Biology, University of Trento, Trento, via delle Regole, 101 38123 Mattarello (TN) Italy and Department of Biotechnology, University of Verona, Province of Verona, Ca' Vignal 1, Strada Le Grazie 15 37134 Verona, Italy
| | - Paola Riva
- Laboratory of Translational Genomics, Centre for Integrative Biology, University of Trento, Trento, via delle Regole, 101 38123 Mattarello (TN) Italy, Department of Medical Biotechnology and Translational Medicine, University of Milan, Milan, via Viotti, 3/5 20133 Milano, Italy, Laboratory of Genomic Screening, Centre for Integrative Biology, University of Trento, Trento, via delle Regole, 101 38123 Mattarello (TN) Italy and Department of Biotechnology, University of Verona, Province of Verona, Ca' Vignal 1, Strada Le Grazie 15 37134 Verona, Italy
| | - Alessandro Quattrone
- Laboratory of Translational Genomics, Centre for Integrative Biology, University of Trento, Trento, via delle Regole, 101 38123 Mattarello (TN) Italy, Department of Medical Biotechnology and Translational Medicine, University of Milan, Milan, via Viotti, 3/5 20133 Milano, Italy, Laboratory of Genomic Screening, Centre for Integrative Biology, University of Trento, Trento, via delle Regole, 101 38123 Mattarello (TN) Italy and Department of Biotechnology, University of Verona, Province of Verona, Ca' Vignal 1, Strada Le Grazie 15 37134 Verona, Italy
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Hsia TC, Tu CY, Chen YJ, Wei YL, Yu MC, Hsu SC, Tsai SL, Chen WS, Yeh MH, Yen CJ, Yu YL, Huang TC, Huang CY, Hung MC, Huang WC. Lapatinib-mediated cyclooxygenase-2 expression via epidermal growth factor receptor/HuR interaction enhances the aggressiveness of triple-negative breast cancer cells. Mol Pharmacol 2013; 83:857-69. [PMID: 23355539 DOI: 10.1124/mol.112.082743] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Lapatinib, a dual epidermal growth factor receptor (EGFR)/human epidermal growth factor receptor 2 (HER2) kinase inhibitor, showed clinical benefits in advanced HER2-positive breast cancer patients. Because some triple-negative breast cancers (TNBCs) frequently overexpress EGFR, the antitumor activity of lapatinib in such diseases was also tested. However, the results showed a worse event-free survival rate. It remains unknown whether and how lapatinib elicits the aggressiveness of such cancer cells. In this study, our results demonstrated that lapatinib facilitated axillary and lung metastases of triple-negative MDA-MB-231 breast cancer cells without affecting their viability, leading to worse survival in orthotopic xenograft mice. The lapatinib-increased motility was attributed by the elevation of EGFR through the downregulation of microRNA-7 and by the subsequent overexpression of cyclooxygenase-2 (COX-2). Strikingly, independent of its kinase activity, the elevated EGFR at least partly stabilized COX-2 expression by enhancing the binding of HuR to COX-2 mRNA. Our results suggest that lapatinib may increase the migration and invasion of MDA-MB-231 cells by upregulating EGFR and COX-2 through the downregulation of microRNA-7, providing a potential explanation for the worse clinical outcome of TNBC patients who receive lapatinib-based treatment. These findings also shed new light on the molecular mechanism of COX-2 mRNA stabilization by EGFR in a kinase-independent manner.
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Affiliation(s)
- Te-Chun Hsia
- Department of Internal Medicine, China Medical University and Hospital, Taichung, Taiwan
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42
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Banadakoppa M, Liebenthal D, Nowak DE, Urvil P, Yallampalli U, Wilson GM, Kishor A, Yallampalli C. Role of transcription factor Sp1 and RNA binding protein HuR in the downregulation of Dr+ Escherichia coli receptor protein decay accelerating factor (DAF or CD55) by nitric oxide. FEBS J 2013; 280:840-54. [PMID: 23176121 DOI: 10.1111/febs.12073] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2012] [Revised: 09/13/2012] [Accepted: 11/21/2012] [Indexed: 12/12/2022]
Abstract
We previously reported that nitric oxide (NO) reduces the rate of bacteremia and maternal mortality in pregnant rats with uterine infection by Escherichia coli expressing the Dr Fimbria (Dr(+) ). The epithelial invasion of Dr(+) E. coli is dependent on the expression level of its cellular receptor decay accelerating factor (DAF). NO reduces the rate of bacteremia by downregulating the expression of DAF. In this study, we elucidated the role of transcription factor Sp1 and RNA binding protein HuR in the downregulation of human DAF by NO. We generated a series of deletion mutant constructs of DAF gene 5'-untranslated region and mapped the NO-response region upstream to the core promoter region of the DAF gene. One of the several Sp1 binding sites in the DAF 5'-untranslated region was located within the NO-response region. The binding of Sp1 to this site was inhibited by NO. Furthermore, NO also promoted the degradation of DAF mRNA. The 3'-untranslated region of DAF harbors an AU-rich element and this element destabilized the mRNA transcript. NO promoted the rapid degradation of DAF mRNA by inhibiting the binding of mRNA stabilizing protein HuR to this AU-rich region. The inhibition of binding of HuR to the AU-rich region was due to the S-nitrosylation of one or more cysteine residues by NO. Thus, these data reveal the molecular mediators of transcriptional and post-transcriptional regulation of DAF by NO with implications in pathophysiology related to DAF.
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Affiliation(s)
- Manu Banadakoppa
- Department of Obstetrics and Gynecology, University of Texas Medical Branch, Galveston, TX 77555, USA
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43
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Damgaard CK, Lykke-Andersen J. Regulation of ARE-mRNA Stability by Cellular Signaling: Implications for Human Cancer. Cancer Treat Res 2013; 158:153-80. [PMID: 24222358 DOI: 10.1007/978-3-642-31659-3_7] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
During recent years, it has become clear that regulation of mRNA stability is an important event in the control of gene expression. The stability of a large class of mammalian mRNAs is regulated by AU-rich elements (AREs) located in the mRNA 3' UTRs. mRNAs with AREs are inherently labile but as a response to different cellular cues they can become either stabilized, allowing expression of a given gene, or further destabilized to silence their expression. These tightly regulated mRNAs include many that encode growth factors, proto-oncogenes, cytokines, and cell cycle regulators. Failure to properly regulate their stability can therefore lead to uncontrolled expression of factors associated with cell proliferation and has been implicated in several human cancers. A number of transfactors that recognize AREs and regulate the translation and degradation of ARE-mRNAs have been identified. These transfactors are regulated by signal transduction pathways, which are often misregulated in cancers. This chapter focuses on the function of ARE-binding proteins with an emphasis on their regulation by signaling pathways and the implications for human cancer.
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44
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Venigalla RKC, Turner M. RNA-binding proteins as a point of convergence of the PI3K and p38 MAPK pathways. Front Immunol 2012; 3:398. [PMID: 23272005 PMCID: PMC3530045 DOI: 10.3389/fimmu.2012.00398] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2012] [Accepted: 12/10/2012] [Indexed: 12/26/2022] Open
Abstract
Understanding the mechanisms by which signal transduction pathways mediate changes in RNA abundance requires the examination of the fate of RNA from its transcription to its degradation. Evidence suggests that RNA abundance is partly regulated by post-transcriptional mechanisms affecting RNA decay and this in turn is modulated by some of the same signaling pathways that control transcription. Furthermore, the translation of mRNA is a key regulatory step that is influenced by signal transduction. These processes are regulated, in part, by RNA-binding proteins (RBPs) which bind to sequence-specific RNA elements. The function of RBPs is controlled and co-ordinated by phosphorylation. Based on the current literature we hypothesize that RBPs may be a point of convergence for the activity of different kinases such as phosphoinositide-3-kinase and mitogen-activated protein kinase which regulate RBP localization and function.
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Affiliation(s)
- Ram K C Venigalla
- Laboratory of Lymphocyte Signalling and Development, The Babraham Institute Babraham, UK
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45
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Chu PC, Chuang HC, Kulp SK, Chen CS. The mRNA-stabilizing factor HuR protein is targeted by β-TrCP protein for degradation in response to glycolysis inhibition. J Biol Chem 2012; 287:43639-50. [PMID: 23115237 DOI: 10.1074/jbc.m112.393678] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
The mRNA-stabilizing protein HuR acts a stress response protein whose function and/or protein stability are modulated by diverse stress stimuli through posttranslational modifications. Here, we report a novel mechanism by which metabolic stress facilitates proteasomal degradation of HuR in cancer cells. In response to the glucose transporter inhibitor CG-5, HuR translocates to the cytoplasm, where it is targeted by the ubiquitin E3 ligase β-TrCP1 for degradation. The cytoplasmic localization of HuR is facilitated by PKCα-mediated phosphorylation at Ser-318 as the Ser-318 → alanine substitution abolishes the ability of the resulting HuR to bind PKCα and to undergo nuclear export. The mechanistic link between β-TrCP1 and HuR degradation was supported by the ability of ectopically expressed β-TrCP1 to mimic CG-5 to promote HuR degradation and by the protective effect of dominant negative inhibition of β-TrCP1 on HuR ubiquitination and degradation. Substrate targeting of HuR by β-TrCP1 was further verified by coimmunoprecipitation and in vitro GST pull-down assays and by the identification of a β-TrCP1 recognition site. Although HuR does not contain a DSG destruction motif, we obtained evidence that β-TrCP1 recognizes an unconventional motif, (296)EEAMAIAS(304), in the RNA recognition motif 3. Furthermore, mutational analysis indicates that IKKα-dependent phosphorylation at Ser-304 is crucial to the binding of HuR to β-TrCP1. Mechanistically, this HuR degradation pathway differs from that reported for heat shock and hypoxia, which underlies the complexity in the regulation of HuR turnover under different stress stimuli. The ability of glycolysis inhibitors to target the expression of oncogenic proteins through HuR degradation might foster novel strategies for cancer therapy.
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Affiliation(s)
- Po-Chen Chu
- Division of Medicinal Chemistry, College of Pharmacy and Comprehensive Cancer Center, The Ohio State University, Columbus, Ohio 43221, USA
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46
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St Laurent G, Shtokalo D, Heydarian M, Palyanov A, Babiy D, Zhou J, Kumar A, Urcuqui-Inchima S. Insights from the HuR-interacting transcriptome: ncRNAs, ubiquitin pathways, and patterns of secondary structure dependent RNA interactions. Mol Genet Genomics 2012; 287:867-79. [PMID: 23052832 DOI: 10.1007/s00438-012-0722-8] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2012] [Accepted: 09/17/2012] [Indexed: 12/22/2022]
Abstract
The HuR protein regulates the expression of thousands of cellular transcripts by modulating mRNA splicing, trafficking, translation, and stability. Although it serves as a model of RNA-protein interactions, many features of HuR's interactions with RNAs remain unknown. In this report, we deployed the cryogenic RNA immunoprecipitation technique to analyze HuR-interacting RNAs with the Affymetrix all-exon microarray platform. We revealed several thousand novel HuR-interacting RNAs, including hundreds of non-coding RNAs such as natural antisense transcripts from stress responsive loci. To gain insight into the mechanisms of specificity and sensitivity of HuR's interaction with its target RNAs, we searched HuR-interacting RNAs for composite patterns of primary sequence and secondary structure. We provide evidence that secondary structures of 66-75 nucleotides enhance HuR's recognition of its specific RNA targets composed of short primary sequence patterns. We validated thousands of these RNAs by analysis of overlap with recently published findings, including HuR's interaction with RNAs in the pathways of RNA splicing and stability. Finally, we observed a striking enrichment for members of ubiquitin ligase pathways among the HuR-interacting mRNAs, suggesting a new role for HuR in the regulation of protein degradation to mirror its known function in protein translation.
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Affiliation(s)
- Georges St Laurent
- Grupo de Inmunovirologia, Universidad de Antioquia, Calle 67 Número 53-108, Medellin, Antioquia, Colombia.
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Dickson AM, Anderson JR, Barnhart MD, Sokoloski KJ, Oko L, Opyrchal M, Galanis E, Wilusz CJ, Morrison TE, Wilusz J. Dephosphorylation of HuR protein during alphavirus infection is associated with HuR relocalization to the cytoplasm. J Biol Chem 2012; 287:36229-38. [PMID: 22915590 DOI: 10.1074/jbc.m112.371203] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
We have demonstrated previously that the cellular HuR protein binds U-rich elements in the 3' untranslated region (UTR) of Sindbis virus RNA and relocalizes from the nucleus to the cytoplasm upon Sindbis virus infection in 293T cells. In this study, we show that two alphaviruses, Ross River virus and Chikungunya virus, lack the conserved high-affinity U-rich HuR binding element in their 3' UTRs but still maintain the ability to interact with HuR with nanomolar affinities through alternative binding elements. The relocalization of HuR protein occurs during Sindbis infection of multiple mammalian cell types as well as during infections with three other alphaviruses. Interestingly, the relocalization of HuR is not a general cellular reaction to viral infection, as HuR protein remained largely nuclear during infections with dengue and measles virus. Relocalization of HuR in a Sindbis infection required viral gene expression, was independent of the presence of a high-affinity U-rich HuR binding site in the 3' UTR of the virus, and was associated with an alteration in the phosphorylation state of HuR. Sindbis virus-induced HuR relocalization was mechanistically distinct from the movement of HuR observed during a cellular stress response, as there was no accumulation of caspase-mediated HuR cleavage products. Collectively, these data indicate that virus-induced HuR relocalization to the cytoplasm is specific to alphavirus infections and is associated with distinct posttranslational modifications of this RNA-binding protein.
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Affiliation(s)
- Alexa M Dickson
- Department of Microbiology, Immunology, and Pathology, Colorado State University, Fort Collins, Colorado 80523, USA
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48
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The H19 lincRNA is a developmental reservoir of miR-675 that suppresses growth and Igf1r. Nat Cell Biol 2012; 14:659-65. [PMID: 22684254 PMCID: PMC3389517 DOI: 10.1038/ncb2521] [Citation(s) in RCA: 640] [Impact Index Per Article: 53.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2011] [Accepted: 05/10/2012] [Indexed: 12/15/2022]
Abstract
The H19 large intergenic noncoding RNA (lincRNA) is one of the most highly abundant and conserved transcripts in mammalian development, being expressed in both embryonic and extraembryonic cell lineages, yet its physiological function is unknown. Here we show that miR-675, a microRNA (miRNA) embedded within H19’s first exon, is expressed exclusively in the placenta from the gestational time point when placental growth normally ceases, and placentas that lack H19 continue to grow. Overexpression of miR-675 in a range of embryonic and extraembryonic cell lines results in their reduced proliferation; targets of the miRNA are upregulated in the H19 null placenta, including the growth promoting Insulin-like growth factor 1 receptor (Igf1r). Moreover, the excision of miR-675 from H19 is dynamically regulated by the stress response RNA binding protein HuR. These results suggest that H19’s main physiological role is in limiting growth of the placenta prior to birth, by regulated processing of miR-675. The controlled release of miR-675 from H19 may also allow rapid inhibition of cell proliferation in response to cellular stress or oncogenic signals.
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Abstract
Nucleolin is a multifunctional protein localized primarily in the nucleolus, but also found in the nucleoplasm, cytoplasm and cell membrane. It is involved in several aspects of DNA metabolism, and participates extensively in RNA regulatory mechanisms, including transcription, ribosome assembly, mRNA stability and translation, and microRNA processing. Nucleolin's implication in disease is linked to its ability to associate with target RNAs via its four RNA-binding domains and its arginine/glycin-rich domain. By modulating the post-transcriptional fate of target mRNAs, which typically bear AU-rich and/or G-rich elements, nucleolin has been linked to cellular events that influence disease, notably cell proliferation and protection against apoptotic death. Through its diverse RNA functions, nucleolin is increasingly implicated in pathological processes, particularly cancer and viral infection. Here, we review the RNA-binding activities of nucleolin, its influence on gene expression patterns, and its impact upon diseases. We also discuss the rising interest in targeting nucleolin therapeutically.
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Affiliation(s)
- Kotb Abdelmohsen
- Laboratory of Molecular Biology and Immunology, National Institute on Aging-Intramural Research Program, National Institutes of Health, Baltimore, MD, USA.
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Downregulation of HuR as a new mechanism of doxorubicin resistance in breast cancer cells. Mol Cancer 2012; 11:13. [PMID: 22436134 PMCID: PMC3325864 DOI: 10.1186/1476-4598-11-13] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2011] [Accepted: 03/21/2012] [Indexed: 11/10/2022] Open
Abstract
Background HuR, an RNA binding protein involved in the post-transcriptional regulation of a wide spectrum of mRNAs, has been demonstrated to be a determinant of carcinogenesis and tumor aggressiveness in several cancer types. In this study, we investigated the role of HuR in the apoptosis and in the chemoresistance induced by the widely used anticancer drug doxorubicin in human breast cancer cells (MCF-7). Results We showed that HuR acts in the early phase of cell response to doxorubicin, being induced to translocate into the cytoplasm upon phosphorylation. Reducing HuR levels diminished the apoptotic response to doxorubicin. Doxorubicin-induced apoptosis was also correlated with the presence of HuR in the cytoplasm. Rottlerin, which was able to block HuR nuclear export, had correspondingly antagonistic effects with doxorubicin on cell toxicity. The proapoptotic activity of HuR was not due to cleavage to an active form, as was previously reported. In in vitro selected doxorubicin resistant MCF-7 cells (MCF-7/doxoR) overexpressing the multidrug resistance (MDR) related ABCG2 transporter, we observed a significant HuR downregulation that was paralleled by a corresponding downregulation of HuR targets and by loss of rottlerin toxicity. Restoration of HuR expression in these cells resensitized MCF-7/doxoR cells to doxorubicin, reactivating the apoptotic response. Conclusions The present study shows that HuR is necessary to elicit the apoptotic cell response to doxorubicin and that restoration of HuR expression in resistant cells resensitizes them to the action of this drug, thereby identifying HuR as a key protein in doxorubicin pharmacology.
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