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Wilson RB, Kozlov AM, Hatam Tehrani H, Twumasi-Ankrah JS, Chen YJ, Borrelli MJ, Sawyez CG, Maini S, Shepherd TG, Cumming RC, Betts DH, Borradaile NM. Elongation factor 1A1 regulates metabolic substrate preference in mammalian cells. J Biol Chem 2024; 300:105684. [PMID: 38272231 PMCID: PMC10891338 DOI: 10.1016/j.jbc.2024.105684] [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: 08/04/2023] [Revised: 12/28/2023] [Accepted: 01/09/2024] [Indexed: 01/27/2024] Open
Abstract
Eukaryotic elongation factor 1A1 (EEF1A1) is canonically involved in protein synthesis but also has noncanonical functions in diverse cellular processes. Previously, we identified EEF1A1 as a mediator of lipotoxicity and demonstrated that chemical inhibition of EEF1A1 activity reduced mouse liver lipid accumulation. These findings suggested a link between EEF1A1 and metabolism. Therefore, we investigated its role in regulating metabolic substrate preference. EEF1A1-deficient Chinese hamster ovary (2E2) cells displayed reduced media lactate accumulation. These effects were also observed with EEF1A1 knockdown in human hepatocyte-like HepG2 cells and in WT Chinese hamster ovary and HepG2 cells treated with selective EEF1A inhibitors, didemnin B, or plitidepsin. Extracellular flux analyses revealed decreased glycolytic ATP production and increased mitochondrial-to-glycolytic ATP production ratio in 2E2 cells, suggesting a more oxidative metabolic phenotype. Correspondingly, fatty acid oxidation was increased in 2E2 cells. Both 2E2 cells and HepG2 cells treated with didemnin B exhibited increased neutral lipid content, which may be required to support elevated oxidative metabolism. RNA-seq revealed a >90-fold downregulation of a rate-limiting glycolytic enzyme, hexokinase 2, which we confirmed through immunoblotting and enzyme activity assays. Pathway enrichment analysis identified downregulations in TNFA signaling via NFKB and MYC targets. Correspondingly, nuclear abundances of RELB and MYC were reduced in 2E2 cells. Thus, EEF1A1 deficiency may perturb glycolysis by limiting NFKB- and MYC-mediated gene expression, leading to decreased hexokinase expression and activity. This is the first evidence of a role for a translation elongation factor, EEF1A1, in regulating metabolic substrate utilization in mammalian cells.
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Affiliation(s)
- Rachel B Wilson
- Department of Physiology and Pharmacology, Schulich School of Medicine and Dentistry, Western University, London, Ontario, Canada
| | | | - Helia Hatam Tehrani
- Department of Physiology and Pharmacology, Schulich School of Medicine and Dentistry, Western University, London, Ontario, Canada
| | - Jessica S Twumasi-Ankrah
- Department of Physiology and Pharmacology, Schulich School of Medicine and Dentistry, Western University, London, Ontario, Canada
| | - Yun Jin Chen
- Department of Physiology and Pharmacology, Schulich School of Medicine and Dentistry, Western University, London, Ontario, Canada
| | - Matthew J Borrelli
- The Mary & John Knight Translational Ovarian Cancer Research Unit, London Regional Cancer Program, London, Ontario, Canada; Department of Anatomy and Cell Biology, Schulich School of Medicine and Dentistry, Western University, London, Ontario, Canada
| | - Cynthia G Sawyez
- Department of Physiology and Pharmacology, Schulich School of Medicine and Dentistry, Western University, London, Ontario, Canada
| | - Siddhant Maini
- Department of Physiology and Pharmacology, Schulich School of Medicine and Dentistry, Western University, London, Ontario, Canada
| | - Trevor G Shepherd
- The Mary & John Knight Translational Ovarian Cancer Research Unit, London Regional Cancer Program, London, Ontario, Canada; Department of Anatomy and Cell Biology, Schulich School of Medicine and Dentistry, Western University, London, Ontario, Canada; Department of Oncology, Schulich School of Medicine and Dentistry, Western University, London, Ontario, Canada; Department of Obstetrics and Gynaecology, Schulich School of Medicine and Dentistry, Western University, London, Ontario, Canada
| | - Robert C Cumming
- Department of Biology, Western University, London, Ontario, Canada; Genetics and Development Division, The Children's Health Research Institute, Lawson Health Research Institute, London, Ontario, Canada
| | - Dean H Betts
- Department of Physiology and Pharmacology, Schulich School of Medicine and Dentistry, Western University, London, Ontario, Canada; Department of Biology, Western University, London, Ontario, Canada; Department of Obstetrics and Gynaecology, Schulich School of Medicine and Dentistry, Western University, London, Ontario, Canada; Genetics and Development Division, The Children's Health Research Institute, Lawson Health Research Institute, London, Ontario, Canada
| | - Nica M Borradaile
- Department of Physiology and Pharmacology, Schulich School of Medicine and Dentistry, Western University, London, Ontario, Canada.
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2
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Hernández G, Vazquez-Pianzola P. eIF4E as a molecular wildcard in metazoans RNA metabolism. Biol Rev Camb Philos Soc 2023; 98:2284-2306. [PMID: 37553111 DOI: 10.1111/brv.13005] [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: 02/09/2023] [Revised: 07/01/2023] [Accepted: 07/25/2023] [Indexed: 08/10/2023]
Abstract
The evolutionary origin of eukaryotes spurred the transition from prokaryotic-like translation to a more sophisticated, eukaryotic translation. During this process, successive gene duplication of a single, primordial eIF4E gene encoding the mRNA cap-binding protein eukaryotic translation initiation factor 4E (eIF4E) gave rise to a plethora of paralog genes across eukaryotes that underwent further functional diversification in RNA metabolism. The ability to take different roles is due to eIF4E promiscuity in binding many partner proteins, rendering eIF4E a highly versatile and multifunctional player that functions as a molecular wildcard. Thus, in metazoans, eIF4E paralogs are involved in various processes, including messenger RNA (mRNA) processing, export, translation, storage, and decay. Moreover, some paralogs display differential expression in tissues and developmental stages and show variable biochemical properties. In this review, we discuss recent advances shedding light on the functional diversification of eIF4E in metazoans. We emphasise humans and two phylogenetically distant species which have become paradigms for studies on development, namely the fruit fly Drosophila melanogaster and the roundworm Caenorhabditis elegans.
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Affiliation(s)
- Greco Hernández
- mRNA and Cancer Laboratory, Unit of Biomedical Research on Cancer, National Institute of Cancer (Instituto Nacional de Cancerología, INCan), 22 San Fernando Ave., Tlalpan, Mexico City, 14080, Mexico
| | - Paula Vazquez-Pianzola
- Institute of Cell Biology, University of Bern, Baltzerstrasse 4, Berne, 3012, Switzerland
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3
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Pallikkuth S, Andre M, Ovens F, Davis S, Chavez J, McDonald C, Raymond A, El-Hage N, Carrico A, Shembade N, Chen Z, Pahwa S. An Overview of Miami CDEIPI and a Showcase of Team Science and Cutting-Edge Research Driven by Students. J Acquir Immune Defic Syndr 2023; 94:S93-S98. [PMID: 37707855 PMCID: PMC11267984 DOI: 10.1097/qai.0000000000003254] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/15/2023]
Abstract
BACKGROUND The Miami-CFAR Diversity, Equity & Inclusion Pathway Initiative (Miami CDEIPI) is designed to promote a diverse scientific workforce that reflects the communities at the highest risk of HIV in South Florida. SETTING AND METHODS The focus of the Miami CDEIPI is to help train the next generation of Underrepresented Minorities (URM) and Black, Indigenous, People of Color (BIPOC) in HIV/AIDS-related research through a team science experience. The Miami CDEIPI objectives are to facilitate the interaction of URM/BIPOC students with the network of CFAR-affiliated investigators and to enable these students to access the cutting-edge technologies at the Miami-CFAR and the Sylvester Comprehensive Cancer Center and other resources at the University of Miami. RESULTS Five URM/BIPOC students supported by the program in year 1 have been carrying out projects in collaboration with mentors at their parent institution and Miami-CFAR investigators. The students used the state-of-the-art laboratories and core facilities. They began their research with a proposal designed to integrate the cutting-edge technologies now available to them. Their training included participation in Miami-CFAR-sponsored activities such as seminars, an annual conference, and a national HIV workshop. Candidates in the Miami CDEIPI are in the process of developing their research proposals, integrating cutting-edge technologies into their doctoral dissertation research. Their projects are now in the completion phase. CONCLUSIONS The Miami CDEIPI focuses its resources on one of the conspicuous gaps in the career paths of URM/BIPOC researchers-the dearth of leading URM/BIPOC scientists in the field. The Miami CDEIPI provides a professional network that supports the participation of URM/BIPOC trainees in innovative research and career skill training.
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Affiliation(s)
- Suresh Pallikkuth
- Department of Microbiology and Immunology, Center for AIDS research, University of Miami School of Medicine, Miami, FL, USA
| | - Mickensone Andre
- Department of Immunology and Nanomedicine, Herbert Wertheim College of Medicine, Miami, FL 33199, USA
| | - Florida Ovens
- Department of Immunology and Nanomedicine, Herbert Wertheim College of Medicine, Miami, FL 33199, USA
| | - Sheldon Davis
- Department of Microbiology and Immunology, Center for AIDS research, University of Miami School of Medicine, Miami, FL, USA
| | - Jennifer Chavez
- Department of Public Health Sciences, University of Miami Miller School of Medicine, Miami, FL, United States of America
| | - Christian McDonald
- Department of Microbiology and Immunology, Center for AIDS research, University of Miami School of Medicine, Miami, FL, USA
| | - Andrea Raymond
- Department of Immunology and Nanomedicine, Herbert Wertheim College of Medicine, Miami, FL 33199, USA
| | - Nazira El-Hage
- Department of Immunology and Nanomedicine, Herbert Wertheim College of Medicine, Miami, FL 33199, USA
| | - Adam Carrico
- Department of Public Health Sciences, University of Miami Miller School of Medicine, Miami, FL, United States of America
| | - Noula Shembade
- Department of Microbiology and Immunology, Center for AIDS research, University of Miami School of Medicine, Miami, FL, USA
| | - Zhibin Chen
- Department of Microbiology and Immunology, Center for AIDS research, University of Miami School of Medicine, Miami, FL, USA
| | - Savita Pahwa
- Department of Microbiology and Immunology, Center for AIDS research, University of Miami School of Medicine, Miami, FL, USA
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4
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Liang M, Hody C, Yammine V, Soin R, Sun Y, Lin X, Tian X, Meurs R, Perdrau C, Delacourt N, Oumalis M, Andris F, Conrard L, Kruys V, Gueydan C. eIF4EHP promotes Ldh mRNA translation in and fruit fly adaptation to hypoxia. EMBO Rep 2023; 24:e56460. [PMID: 37144276 PMCID: PMC10328074 DOI: 10.15252/embr.202256460] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2022] [Revised: 04/16/2023] [Accepted: 04/21/2023] [Indexed: 05/06/2023] Open
Abstract
Hypoxia induces profound modifications in the gene expression program of eukaryotic cells due to lowered ATP supply resulting from the blockade of oxidative phosphorylation. One significant consequence of oxygen deprivation is the massive repression of protein synthesis, leaving a limited set of mRNAs to be translated. Drosophila melanogaster is strongly resistant to oxygen fluctuations; however, the mechanisms allowing specific mRNA to be translated into hypoxia are still unknown. Here, we show that Ldh mRNA encoding lactate dehydrogenase is highly translated into hypoxia by a mechanism involving a CA-rich motif present in its 3' untranslated region. Furthermore, we identified the cap-binding protein eIF4EHP as a main factor involved in 3'UTR-dependent translation under hypoxia. In accordance with this observation, we show that eIF4EHP is necessary for Drosophila development under low oxygen concentrations and contributes to Drosophila mobility after hypoxic challenge. Altogether, our data bring new insight into mechanisms contributing to LDH production and Drosophila adaptation to oxygen variations.
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Affiliation(s)
- Manfei Liang
- Laboratoire de Biologie Moléculaire du GèneUniversité libre de Bruxelles (ULB)GosseliesBelgium
- Present address:
Medical Science and Technology Innovation CenterShandong First Medical UniversityJinanChina
| | - Clara Hody
- Laboratoire de Biologie Moléculaire du GèneUniversité libre de Bruxelles (ULB)GosseliesBelgium
| | - Vanessa Yammine
- Laboratoire de Biologie Moléculaire du GèneUniversité libre de Bruxelles (ULB)GosseliesBelgium
| | - Romuald Soin
- Laboratoire de Biologie Moléculaire du GèneUniversité libre de Bruxelles (ULB)GosseliesBelgium
| | - Yuqiu Sun
- Laboratoire de Biologie Moléculaire du GèneUniversité libre de Bruxelles (ULB)GosseliesBelgium
| | - Xing Lin
- Laboratoire de Biologie Moléculaire du GèneUniversité libre de Bruxelles (ULB)GosseliesBelgium
| | - Xiaoying Tian
- Laboratoire de Biologie Moléculaire du GèneUniversité libre de Bruxelles (ULB)GosseliesBelgium
| | - Romane Meurs
- Laboratoire de Biologie Moléculaire du GèneUniversité libre de Bruxelles (ULB)GosseliesBelgium
| | - Camille Perdrau
- Laboratoire de Biologie Moléculaire du GèneUniversité libre de Bruxelles (ULB)GosseliesBelgium
| | - Nadège Delacourt
- Laboratoire de Biologie Moléculaire du GèneUniversité libre de Bruxelles (ULB)GosseliesBelgium
| | - Marina Oumalis
- Laboratoire de Biologie Moléculaire du GèneUniversité libre de Bruxelles (ULB)GosseliesBelgium
| | - Fabienne Andris
- Laboratoire d'Immunobiologie, Faculté des SciencesUniversité libre de Bruxelles (ULB)GosseliesBelgium
| | - Louise Conrard
- Center of Microscopy and Molecular Imaging (CMMI)Université libre de Bruxelles (ULB)GosseliesBelgium
| | - Véronique Kruys
- Laboratoire de Biologie Moléculaire du GèneUniversité libre de Bruxelles (ULB)GosseliesBelgium
| | - Cyril Gueydan
- Laboratoire de Biologie Moléculaire du GèneUniversité libre de Bruxelles (ULB)GosseliesBelgium
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5
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Montiel-Dávalos A, Ayala Y, Hernández G. The dark side of mRNA translation and the translation machinery in glioblastoma. Front Cell Dev Biol 2023; 11:1086964. [PMID: 36994107 PMCID: PMC10042294 DOI: 10.3389/fcell.2023.1086964] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2022] [Accepted: 03/03/2023] [Indexed: 03/14/2023] Open
Abstract
Among the different types of cancer affecting the central nervous system (CNS), glioblastoma (GB) is classified by the World Health Organization (WHO) as the most common and aggressive CNS cancer in adults. GB incidence is more frequent among persons aged 45–55 years old. GB treatments are based on tumor resection, radiation, and chemotherapies. The current development of novel molecular biomarkers (MB) has led to a more accurate prediction of GB progression. Moreover, clinical, epidemiological, and experimental studies have established genetic variants consistently associated with the risk of suffering GB. However, despite the advances in these fields, the survival expectancy of GB patients is still shorter than 2 years. Thus, fundamental processes inducing tumor onset and progression remain to be elucidated. In recent years, mRNA translation has been in the spotlight, as its dysregulation is emerging as a key cause of GB. In particular, the initiation phase of translation is most involved in this process. Among the crucial events, the machinery performing this phase undergoes a reconfiguration under the hypoxic conditions in the tumor microenvironment. In addition, ribosomal proteins (RPs) have been reported to play translation-independent roles in GB development. This review focuses on the research elucidating the tight relationship between translation initiation, the translation machinery, and GB. We also summarize the state-of-the-art drugs targeting the translation machinery to improve patients’ survival. Overall, the recent advances in this field are shedding new light on the dark side of translation in GB.
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6
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Ho JD, Cunningham TA, Krieger JR, Schatz JH, Lee S. MATRIX platform to analyze translation machinery remodeling in glioblastoma cells. STAR Protoc 2022; 3:101919. [PMID: 36595908 PMCID: PMC9763746 DOI: 10.1016/j.xpro.2022.101919] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2022] [Revised: 09/05/2022] [Accepted: 11/18/2022] [Indexed: 12/14/2022] Open
Abstract
Here, we present a protocol using MATRIX (mass spectrometry analysis of active translation factors using ribosome density fractionation and isotopic labeling experiments) platform to investigate changes of the protein synthesis machinery in U87MG glioblastoma cells in response to the rocaglate silvestrol. This protocol describes steps to perform SILAC (stable isotope labeling by amino acids in cell culture), ribosome density fractionation, protein isolation, and mass spectrometry analysis. This approach can be applied to study any adaptive remodeling of protein synthesis machineries. For complete details on the use and execution of this protocol, please refer to Ho et al. (2021).1.
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Affiliation(s)
- J.J. David Ho
- Sylvester Comprehensive Cancer Center, Miller School of Medicine, University of Miami, Miami, FL 33136, USA,Division of Hematology, Department of Medicine, Miller School of Medicine, University of Miami, Miami, FL 33136, USA,Corresponding author
| | - Tyler A. Cunningham
- Sylvester Comprehensive Cancer Center, Miller School of Medicine, University of Miami, Miami, FL 33136, USA,Medical Scientist Training Program, Miller School of Medicine, University of Miami, Miami, FL 33136, USA,Molecular and Cellular Pharmacology Graduate Program, Miller School of Medicine, University of Miami, Miami, FL 33136, USA
| | | | - Jonathan H. Schatz
- Sylvester Comprehensive Cancer Center, Miller School of Medicine, University of Miami, Miami, FL 33136, USA,Division of Hematology, Department of Medicine, Miller School of Medicine, University of Miami, Miami, FL 33136, USA,Corresponding author
| | - Stephen Lee
- Sylvester Comprehensive Cancer Center, Miller School of Medicine, University of Miami, Miami, FL 33136, USA,Department of Biochemistry and Molecular Biology, Miller School of Medicine, University of Miami, Miami, FL 33136, USA,Corresponding author
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7
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Kazan R, Bourgeois G, Lazennec-Schurdevin C, Larquet E, Mechulam Y, Coureux PD, Schmitt E. Role of aIF5B in archaeal translation initiation. Nucleic Acids Res 2022; 50:6532-6548. [PMID: 35694843 PMCID: PMC9226500 DOI: 10.1093/nar/gkac490] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2022] [Revised: 05/20/2022] [Accepted: 05/25/2022] [Indexed: 01/22/2023] Open
Abstract
In eukaryotes and in archaea late steps of translation initiation involve the two initiation factors e/aIF5B and e/aIF1A. In eukaryotes, the role of eIF5B in ribosomal subunit joining is established and structural data showing eIF5B bound to the full ribosome were obtained. To achieve its function, eIF5B collaborates with eIF1A. However, structural data illustrating how these two factors interact on the small ribosomal subunit have long been awaited. The role of the archaeal counterparts, aIF5B and aIF1A, remains to be extensively addressed. Here, we study the late steps of Pyrococcus abyssi translation initiation. Using in vitro reconstituted initiation complexes and light scattering, we show that aIF5B bound to GTP accelerates subunit joining without the need for GTP hydrolysis. We report the crystallographic structures of aIF5B bound to GDP and GTP and analyze domain movements associated to these two nucleotide states. Finally, we present the cryo-EM structure of an initiation complex containing 30S bound to mRNA, Met-tRNAiMet, aIF5B and aIF1A at 2.7 Å resolution. Structural data shows how archaeal 5B and 1A factors cooperate to induce a conformation of the initiator tRNA favorable to subunit joining. Archaeal and eukaryotic features of late steps of translation initiation are discussed.
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Affiliation(s)
- Ramy Kazan
- Laboratoire de Biologie Structurale de la Cellule, BIOC, Ecole polytechnique, CNRS, Institut Polytechnique de Paris, 91128 Palaiseau cedex, France
| | - Gabrielle Bourgeois
- Laboratoire de Biologie Structurale de la Cellule, BIOC, Ecole polytechnique, CNRS, Institut Polytechnique de Paris, 91128 Palaiseau cedex, France
| | - Christine Lazennec-Schurdevin
- Laboratoire de Biologie Structurale de la Cellule, BIOC, Ecole polytechnique, CNRS, Institut Polytechnique de Paris, 91128 Palaiseau cedex, France
| | - Eric Larquet
- Laboratoire de Physique de la Matière Condensée, PMC, Ecole polytechnique, CNRS, Institut Polytechnique de Paris, 91128 Palaiseau cedex, France
| | - Yves Mechulam
- Laboratoire de Biologie Structurale de la Cellule, BIOC, Ecole polytechnique, CNRS, Institut Polytechnique de Paris, 91128 Palaiseau cedex, France
| | - Pierre-Damien Coureux
- Laboratoire de Biologie Structurale de la Cellule, BIOC, Ecole polytechnique, CNRS, Institut Polytechnique de Paris, 91128 Palaiseau cedex, France
| | - Emmanuelle Schmitt
- Laboratoire de Biologie Structurale de la Cellule, BIOC, Ecole polytechnique, CNRS, Institut Polytechnique de Paris, 91128 Palaiseau cedex, France
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8
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Probabilistic models of uORF-mediated ATF4 translation control. Math Biosci 2021; 343:108762. [PMID: 34883107 DOI: 10.1016/j.mbs.2021.108762] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2021] [Revised: 10/21/2021] [Accepted: 10/21/2021] [Indexed: 01/08/2023]
Abstract
ATF4 is a key transcription factor that activates transcription of genes needed to respond to cellular stress. Although the mRNA encoding ATF4 is present at constant levels in the cell during the initial response, translation of ATF4 increases under conditions of cellular stress while the global translation rate decreases. We study two models for the control system that regulates the translation of ATF4, both based on the Vattem-Wek hypothesis. This hypothesis is based on a race to reload, following the translation of a small upstream open reading frame (uORF), the ternary complex that brings the initiator tRNA to the ribosome as the 40S subunit scans along the mRNA, encountering first a start codon for an inhibitory uORF whose reading frame overlaps the start of the ATF4 coding sequence. We develop a pair of simple, analytic, probabilistic models, one of which assumes all nucleotide triplets have identical kinetic properties, while the other recognizes the existence of triplets at which the ternary complex loads more efficiently. We also consider two different functions representing the dependence of the rate of initiation at uORF1 on the ternary complex concentration. In keeping with the theme of this Special Issue, we studied the properties of these models in a Maple document, which can easily be modified to consider different parameters, translation rate initiation functions, and so on.
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9
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Priming, Triggering, Adaptation and Senescence (PTAS): A Hypothesis for a Common Damage Mechanism of Steatohepatitis. Int J Mol Sci 2021; 22:ijms222212545. [PMID: 34830427 PMCID: PMC8624051 DOI: 10.3390/ijms222212545] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2021] [Revised: 11/18/2021] [Accepted: 11/19/2021] [Indexed: 11/17/2022] Open
Abstract
Understanding the pathomechanism of steatohepatitis (SH) is hampered by the difficulty of distinguishing between causes and consequences, by the broad spectrum of aetiologies that can produce the phenotype, and by the long time-span during which SH develops, often without clinical symptoms. We propose that SH develops in four phases with transitions: (i) priming lowers stress defence; (ii) triggering leads to acute damage; (iii) adaptation, possibly associated with cellular senescence, mitigates tissue damage, leads to the phenotype, and preserves liver function at a lower level; (iv) finally, senescence prevents neoplastic transformation but favours fibrosis (cirrhosis) and inflammation and further reduction in liver function. Escape from senescence eventually leads to hepatocellular carcinoma. This hypothesis for a pathomechanism of SH is supported by clinical and experimental observations. It allows organizing the various findings to uncover remaining gaps in our knowledge and, finally, to provide possible diagnostic and intervention strategies for each stage of SH development.
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10
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Ho JJD, Cunningham TA, Manara P, Coughlin CA, Arumov A, Roberts ER, Osteen A, Kumar P, Bilbao D, Krieger JR, Lee S, Schatz JH. Proteomics reveal cap-dependent translation inhibitors remodel the translation machinery and translatome. Cell Rep 2021; 37:109806. [PMID: 34644561 PMCID: PMC8558842 DOI: 10.1016/j.celrep.2021.109806] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2021] [Revised: 07/28/2021] [Accepted: 09/16/2021] [Indexed: 12/15/2022] Open
Abstract
Tactical disruption of protein synthesis is an attractive therapeutic strategy, with the first-in-class eIF4A-targeting compound zotatifin in clinical evaluation for cancer and COVID-19. The full cellular impact and mechanisms of these potent molecules are undefined at a proteomic level. Here, we report mass spectrometry analysis of translational reprogramming by rocaglates, cap-dependent initiation disruptors that include zotatifin. We find effects to be far more complex than simple “translational inhibition” as currently defined. Translatome analysis by TMT-pSILAC (tandem mass tag-pulse stable isotope labeling with amino acids in cell culture mass spectrometry) reveals myriad upregulated proteins that drive hitherto unrecognized cytotoxic mechanisms, including GEF-H1-mediated anti-survival RHOA/JNK activation. Surprisingly, these responses are not replicated by eIF4A silencing, indicating a broader translational adaptation than currently understood. Translation machinery analysis by MATRIX (mass spectrometry analysis of active translation factors using ribosome density fractionation and isotopic labeling experiments) identifies rocaglate-specific dependence on specific translation factors including eEF1ε1 that drive translatome remodeling. Our proteome-level interrogation reveals that the complete cellular response to these historical “translation inhibitors” is mediated by comprehensive translational landscape remodeling. Tactical protein synthesis inhibition is actively pursued as a cancer therapy that bypasses signaling redundancies limiting current strategies. Ho et al. show that rocaglates, first identified as inhibitors of eIF4A activity, globally reprogram cellular translation at both protein synthesis machinery and translatome levels, inducing cytotoxicity through anti-survival GEF-H1/RHOA/JNK signaling.
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Affiliation(s)
- J J David Ho
- Sylvester Comprehensive Cancer Center, University of Miami Miller School of Medicine, Miami, FL 33136, USA; Division of Hematology, Department of Medicine, University of Miami Miller School of Medicine, Miami, FL 33136, USA.
| | - Tyler A Cunningham
- Sylvester Comprehensive Cancer Center, University of Miami Miller School of Medicine, Miami, FL 33136, USA; Medical Scientist Training Program, University of Miami Miller School of Medicine, Miami, FL 33136, USA; Molecular and Cellular Pharmacology Graduate Program, University of Miami Miller School of Medicine, Miami, FL 33136, USA
| | - Paola Manara
- Sylvester Comprehensive Cancer Center, University of Miami Miller School of Medicine, Miami, FL 33136, USA; Sheila and David Fuente Graduate Program in Cancer Biology, University of Miami Miller School of Medicine, Miami, FL 33136, USA
| | - Caroline A Coughlin
- Sylvester Comprehensive Cancer Center, University of Miami Miller School of Medicine, Miami, FL 33136, USA; Medical Scientist Training Program, University of Miami Miller School of Medicine, Miami, FL 33136, USA; Sheila and David Fuente Graduate Program in Cancer Biology, University of Miami Miller School of Medicine, Miami, FL 33136, USA
| | - Artavazd Arumov
- Sylvester Comprehensive Cancer Center, University of Miami Miller School of Medicine, Miami, FL 33136, USA; Sheila and David Fuente Graduate Program in Cancer Biology, University of Miami Miller School of Medicine, Miami, FL 33136, USA
| | - Evan R Roberts
- Sylvester Comprehensive Cancer Center, University of Miami Miller School of Medicine, Miami, FL 33136, USA; Cancer Modeling Shared Resource, Sylvester Comprehensive Cancer Center, University of Miami Miller School of Medicine, Miami, FL 33136, USA
| | - Ashanti Osteen
- Sylvester Comprehensive Cancer Center, University of Miami Miller School of Medicine, Miami, FL 33136, USA; Cancer Modeling Shared Resource, Sylvester Comprehensive Cancer Center, University of Miami Miller School of Medicine, Miami, FL 33136, USA
| | - Preet Kumar
- Sylvester Comprehensive Cancer Center, University of Miami Miller School of Medicine, Miami, FL 33136, USA; Division of Hematology, Department of Medicine, University of Miami Miller School of Medicine, Miami, FL 33136, USA
| | - Daniel Bilbao
- Sylvester Comprehensive Cancer Center, University of Miami Miller School of Medicine, Miami, FL 33136, USA; Cancer Modeling Shared Resource, Sylvester Comprehensive Cancer Center, University of Miami Miller School of Medicine, Miami, FL 33136, USA
| | | | - Stephen Lee
- Sylvester Comprehensive Cancer Center, University of Miami Miller School of Medicine, Miami, FL 33136, USA; Department of Biochemistry and Molecular Biology, University of Miami Miller School of Medicine, Miami, FL 33136, USA
| | - Jonathan H Schatz
- Sylvester Comprehensive Cancer Center, University of Miami Miller School of Medicine, Miami, FL 33136, USA; Division of Hematology, Department of Medicine, University of Miami Miller School of Medicine, Miami, FL 33136, USA.
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11
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Chukka PAR, Wetmore SD, Thakor N. Established and Emerging Regulatory Roles of Eukaryotic Translation Initiation Factor 5B (eIF5B). Front Genet 2021; 12:737433. [PMID: 34512736 PMCID: PMC8430213 DOI: 10.3389/fgene.2021.737433] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2021] [Accepted: 08/10/2021] [Indexed: 12/21/2022] Open
Abstract
Translational control (TC) is one the crucial steps that dictate gene expression and alter the outcome of physiological process like programmed cell death, metabolism, and proliferation in a eukaryotic cell. TC occurs mainly at the translation initiation stage. The initiation factor eIF5B tightly regulates global translation initiation and facilitates the expression of a subset of proteins involved in proliferation, inhibition of apoptosis, and immunosuppression under stress conditions. eIF5B enhances the expression of these survival proteins to allow cancer cells to metastasize and resist chemotherapy. Using eIF5B as a biomarker or drug target could help with diagnosis and improved prognosis, respectively. To achieve these goals, it is crucial to understand the role of eIF5B in translational regulation. This review recapitulates eIF5B's regulatory roles in the translation initiation of viral mRNA as well as the cellular mRNAs in cancer and stressed eukaryotic cells.
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Affiliation(s)
- Prakash Amruth Raj Chukka
- Department of Chemistry and Biochemistry, University of Lethbridge, Lethbridge, AB, Canada.,Southern Alberta Genome Sciences Centre (SAGSC), University of Lethbridge, Lethbridge, AB, Canada.,Alberta RNA Research and Training Institute (ARRTI), University of Lethbridge, Lethbridge, AB, Canada.,Canadian Centre of Research in Advanced Fluorine Technologies (C-CRAFT), University of Lethbridge, Lethbridge, AB, Canada
| | - Stacey D Wetmore
- Department of Chemistry and Biochemistry, University of Lethbridge, Lethbridge, AB, Canada.,Southern Alberta Genome Sciences Centre (SAGSC), University of Lethbridge, Lethbridge, AB, Canada.,Alberta RNA Research and Training Institute (ARRTI), University of Lethbridge, Lethbridge, AB, Canada.,Canadian Centre of Research in Advanced Fluorine Technologies (C-CRAFT), University of Lethbridge, Lethbridge, AB, Canada
| | - Nehal Thakor
- Department of Chemistry and Biochemistry, University of Lethbridge, Lethbridge, AB, Canada.,Southern Alberta Genome Sciences Centre (SAGSC), University of Lethbridge, Lethbridge, AB, Canada.,Department of Biological Sciences, University of Lethbridge, Lethbridge, AB, Canada.,Department of Neuroscience, Canadian Centre for Behavioral Neuroscience (CCBN), University of Lethbridge, Lethbridge, AB, Canada.,Arnie Charbonneau Cancer Institute, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada
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12
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Fabbri L, Chakraborty A, Robert C, Vagner S. The plasticity of mRNA translation during cancer progression and therapy resistance. Nat Rev Cancer 2021; 21:558-577. [PMID: 34341537 DOI: 10.1038/s41568-021-00380-y] [Citation(s) in RCA: 89] [Impact Index Per Article: 29.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 06/14/2021] [Indexed: 02/07/2023]
Abstract
Translational control of mRNAs during gene expression allows cells to promptly and dynamically adapt to a variety of stimuli, including in neoplasia in response to aberrant oncogenic signalling (for example, PI3K-AKT-mTOR, RAS-MAPK and MYC) and microenvironmental stress such as low oxygen and nutrient supply. Such translational rewiring allows rapid, specific changes in the cell proteome that shape specific cancer phenotypes to promote cancer onset, progression and resistance to anticancer therapies. In this Review, we illustrate the plasticity of mRNA translation. We first highlight the diverse mechanisms by which it is regulated, including by translation factors (for example, eukaryotic initiation factor 4F (eIF4F) and eIF2), RNA-binding proteins, tRNAs and ribosomal RNAs that are modulated in response to aberrant intracellular pathways or microenvironmental stress. We then describe how translational control can influence tumour behaviour by impacting on the phenotypic plasticity of cancer cells as well as on components of the tumour microenvironment. Finally, we highlight the role of mRNA translation in the cellular response to anticancer therapies and its promise as a key therapeutic target.
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Affiliation(s)
- Lucilla Fabbri
- Institut Curie, PSL Research University, CNRS UMR3348, INSERM U1278, Orsay, France
- Université Paris Sud, Université Paris-Saclay, CNRS UMR3348, INSERM U1278, Orsay, France
- Equipe Labellisée Ligue Nationale Contre le Cancer, Orsay, France
| | - Alina Chakraborty
- Institut Curie, PSL Research University, CNRS UMR3348, INSERM U1278, Orsay, France
- Université Paris Sud, Université Paris-Saclay, CNRS UMR3348, INSERM U1278, Orsay, France
- Equipe Labellisée Ligue Nationale Contre le Cancer, Orsay, France
| | - Caroline Robert
- INSERM U981, Gustave Roussy Cancer Campus, Villejuif, France
- Université Paris-Sud, Université Paris-Saclay, Kremlin-Bicêtre, France
- Dermato-Oncology, Gustave Roussy Cancer Campus, Villejuif, France
| | - Stéphan Vagner
- Institut Curie, PSL Research University, CNRS UMR3348, INSERM U1278, Orsay, France.
- Université Paris Sud, Université Paris-Saclay, CNRS UMR3348, INSERM U1278, Orsay, France.
- Equipe Labellisée Ligue Nationale Contre le Cancer, Orsay, France.
- Dermato-Oncology, Gustave Roussy Cancer Campus, Villejuif, France.
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13
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Suresh S, O'Donnell KA. Translational Control of Immune Evasion in Cancer. Trends Cancer 2021; 7:580-582. [PMID: 33972197 PMCID: PMC8262573 DOI: 10.1016/j.trecan.2021.04.002] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2021] [Revised: 04/09/2021] [Accepted: 04/12/2021] [Indexed: 11/21/2022]
Abstract
Mechanisms that control translation play important roles in tumor progression and metastasis. Emerging evidence has revealed that dysregulated translation also impacts immune evasion in response to cellular or oncogenic stress. Here, we summarize current knowledge regarding the translational control of immune checkpoints and implications for cancer immunotherapies.
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Affiliation(s)
- Shruthy Suresh
- Department of Molecular Biology, University of Texas Southwestern (UTSW) Medical Center, Dallas, TX 75390, USA
| | - Kathryn A O'Donnell
- Department of Molecular Biology, University of Texas Southwestern (UTSW) Medical Center, Dallas, TX 75390, USA; Harold C. Simmons Comprehensive Cancer Center, UTSW Medical Center, Dallas, TX 75390, USA; Hamon Center for Regenerative Science and Medicine, UTSW Medical Center, Dallas, TX 75390, USA.
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14
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Ho JJD, Man JHS, Schatz JH, Marsden PA. Translational remodeling by RNA-binding proteins and noncoding RNAs. WILEY INTERDISCIPLINARY REVIEWS-RNA 2021; 12:e1647. [PMID: 33694288 DOI: 10.1002/wrna.1647] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/21/2020] [Revised: 02/09/2021] [Accepted: 02/10/2021] [Indexed: 12/14/2022]
Abstract
Responsible for generating the proteome that controls phenotype, translation is the ultimate convergence point for myriad upstream signals that influence gene expression. System-wide adaptive translational reprogramming has recently emerged as a pillar of cellular adaptation. As classic regulators of mRNA stability and translation efficiency, foundational studies established the concept of collaboration and competition between RNA-binding proteins (RBPs) and noncoding RNAs (ncRNAs) on individual mRNAs. Fresh conceptual innovations now highlight stress-activated, evolutionarily conserved RBP networks and ncRNAs that increase the translation efficiency of populations of transcripts encoding proteins that participate in a common cellular process. The discovery of post-transcriptional functions for long noncoding RNAs (lncRNAs) was particularly intriguing given their cell-type-specificity and historical definition as nuclear-functioning epigenetic regulators. The convergence of RBPs, lncRNAs, and microRNAs on functionally related mRNAs to enable adaptive protein synthesis is a newer biological paradigm that highlights their role as "translatome (protein output) remodelers" and reinvigorates the paradigm of "RNA operons." Together, these concepts modernize our understanding of cellular stress adaptation and strategies for therapeutic development. This article is categorized under: RNA Interactions with Proteins and Other Molecules > Protein-RNA Interactions: Functional Implications Translation > Translation Regulation Regulatory RNAs/RNAi/Riboswitches > Regulatory RNAs.
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Affiliation(s)
- J J David Ho
- Sylvester Comprehensive Cancer Center, Miller School of Medicine, University of Miami, Miami, Florida, USA.,Division of Hematology, Department of Medicine, Miller School of Medicine, University of Miami, Miami, Florida, USA
| | - Jeffrey H S Man
- Keenan Research Centre, Li Ka Shing Knowledge Institute, St. Michael's Hospital, Toronto, Ontario, Canada.,Department of Medicine, University of Toronto, Toronto, Ontario, Canada.,Department of Respirology, University Health Network, Latner Thoracic Research Laboratories, University of Toronto, Toronto, Ontario, Canada
| | - Jonathan H Schatz
- Sylvester Comprehensive Cancer Center, Miller School of Medicine, University of Miami, Miami, Florida, USA.,Division of Hematology, Department of Medicine, Miller School of Medicine, University of Miami, Miami, Florida, USA
| | - Philip A Marsden
- Keenan Research Centre, Li Ka Shing Knowledge Institute, St. Michael's Hospital, Toronto, Ontario, Canada.,Department of Medicine, University of Toronto, Toronto, Ontario, Canada
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15
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Bressler KR, Ross JA, Ilnytskyy S, Vanden Dungen K, Taylor K, Patel K, Zovoilis A, Kovalchuk I, Thakor N. Depletion of eukaryotic initiation factor 5B (eIF5B) reprograms the cellular transcriptome and leads to activation of endoplasmic reticulum (ER) stress and c-Jun N-terminal kinase (JNK). Cell Stress Chaperones 2021; 26:253-264. [PMID: 33123915 PMCID: PMC7736443 DOI: 10.1007/s12192-020-01174-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2020] [Revised: 10/13/2020] [Accepted: 10/18/2020] [Indexed: 12/17/2022] Open
Abstract
During the integrated stress response (ISR), global translation initiation is attenuated; however, noncanonical mechanisms allow for the continued translation of specific transcripts. Eukaryotic initiation factor 5B (eIF5B) has been shown to play a critical role in canonical translation as well as in noncanonical mechanisms involving internal ribosome entry site (IRES) and upstream open reading frame (uORF) elements. The uORF-mediated translation regulation of activating transcription factor 4 (ATF4) mRNA plays a pivotal role in the cellular ISR. Our recent study confirmed that eIF5B depletion removes uORF2-mediated repression of ATF4 translation, which results in the upregulation of growth arrest and DNA damage-inducible protein 34 (GADD34) transcription. Accordingly, we hypothesized that eIF5B depletion may reprogram the transcriptome profile of the cell. Here, we employed genome-wide transcriptional analysis on eIF5B-depleted cells. Further, we validate the up- and downregulation of several transcripts from our RNA-seq data using RT-qPCR. We identified upregulated pathways including cellular response to endoplasmic reticulum (ER) stress, and mucin-type O-glycan biosynthesis, as well as downregulated pathways of transcriptional misregulation in cancer and T cell receptor signaling. We also confirm that depletion of eIF5B leads to activation of the c-Jun N-terminal kinase (JNK) arm of the mitogen-activated protein kinase (MAPK) pathway. This data suggests that depletion of eIF5B reprograms the cellular transcriptome and influences critical cellular processes such as ER stress and ISR.
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Affiliation(s)
- Kamiko R Bressler
- Department of Chemistry and Biochemistry, University of Lethbridge, 4401 University Drive W, Lethbridge, Alberta, T1K 3M4, Canada
- Cumming School of Medicine, University of Calgary, 3280 Hospital Drive NW, Calgary, Alberta, T2N 4Z6, Canada
| | - Joseph A Ross
- Department of Chemistry and Biochemistry, University of Lethbridge, 4401 University Drive W, Lethbridge, Alberta, T1K 3M4, Canada
- Chinook Contract Research Inc., 97 East Lake Ramp NE, Airdrie, Alberta, T4A 2 K4, Canada
| | - Slava Ilnytskyy
- Department of Biological Sciences, University of Lethbridge, 4401 University Drive W, Lethbridge, Alberta, T1K 3M4, Canada
| | - Keiran Vanden Dungen
- Department of Chemistry and Biochemistry, University of Lethbridge, 4401 University Drive W, Lethbridge, Alberta, T1K 3M4, Canada
| | - Katrina Taylor
- Department of Chemistry and Biochemistry, University of Lethbridge, 4401 University Drive W, Lethbridge, Alberta, T1K 3M4, Canada
| | - Kush Patel
- Department of Chemistry and Biochemistry, University of Lethbridge, 4401 University Drive W, Lethbridge, Alberta, T1K 3M4, Canada
| | - Athanasios Zovoilis
- Department of Chemistry and Biochemistry, University of Lethbridge, 4401 University Drive W, Lethbridge, Alberta, T1K 3M4, Canada
- Canadian Centre for Behavioral Neuroscience (CCBN), Department of Neuroscience, University of Lethbridge, 4401 University Drive W, Lethbridge, Alberta, T1K 3M4, Canada
- Southern Alberta Genome Sciences Centre (SAGSC), University of Lethbridge, 4401 University Drive W, Lethbridge, Alberta, T1K 3 M4, Canada
| | - Igor Kovalchuk
- Department of Biological Sciences, University of Lethbridge, 4401 University Drive W, Lethbridge, Alberta, T1K 3M4, Canada
- Southern Alberta Genome Sciences Centre (SAGSC), University of Lethbridge, 4401 University Drive W, Lethbridge, Alberta, T1K 3 M4, Canada
| | - Nehal Thakor
- Department of Chemistry and Biochemistry, University of Lethbridge, 4401 University Drive W, Lethbridge, Alberta, T1K 3M4, Canada.
- Department of Biological Sciences, University of Lethbridge, 4401 University Drive W, Lethbridge, Alberta, T1K 3M4, Canada.
- Canadian Centre for Behavioral Neuroscience (CCBN), Department of Neuroscience, University of Lethbridge, 4401 University Drive W, Lethbridge, Alberta, T1K 3M4, Canada.
- Southern Alberta Genome Sciences Centre (SAGSC), University of Lethbridge, 4401 University Drive W, Lethbridge, Alberta, T1K 3 M4, Canada.
- Arnie Charbonneau Cancer Institute, Cumming School of Medicine, University of Calgary, 3280 Hospital Drive NW, Calgary, Alberta, T2N 4Z6, Canada.
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16
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Hajj GNM, Nunes PBC, Roffe M. Genome-wide translation patterns in gliomas: An integrative view. Cell Signal 2020; 79:109883. [PMID: 33321181 DOI: 10.1016/j.cellsig.2020.109883] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2020] [Revised: 12/01/2020] [Accepted: 12/11/2020] [Indexed: 02/06/2023]
Abstract
Gliomas are the most frequent tumors of the central nervous system (CNS) and include the highly malignant glioblastoma (GBM). Characteristically, gliomas have translational control deregulation related to overactivation of signaling pathways such as PI3K/AKT/mTORC1 and Ras/ERK1/2. Thus, mRNA translation appears to play a dominant role in glioma gene expression patterns. The, analysis of genome-wide translated transcripts, together known as the translatome, may reveal important information for understanding gene expression patterns in gliomas. This review provides a brief overview of translational control mechanisms altered in gliomas with a focus on the current knowledge related to the translatomes of glioma cells and murine glioma models. We present an integrative meta-analysis of selected glioma translatome data with the aim of identifying recurrent patterns of gene expression preferentially regulated at the level of translation and obtaining clues regarding the pathological significance of these alterations. Re-analysis of several translatome datasets was performed to compare the translatomes of glioma models with those of their non-tumor counterparts and to document glioma cell responses to radiotherapy and MNK modulation. The role of recurrently altered genes in the context of translational control and tumorigenesis are discussed.
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Affiliation(s)
- Glaucia Noeli Maroso Hajj
- International Research Institute, A.C.Camargo Cancer Center, Rua Taguá, 440, São Paulo ZIP Code: 01508-010, Brazil; National Institute of Oncogenomics and Innovation, Brazil.
| | - Paula Borzino Cordeiro Nunes
- International Research Institute, A.C.Camargo Cancer Center, Rua Taguá, 440, São Paulo ZIP Code: 01508-010, Brazil
| | - Martin Roffe
- International Research Institute, A.C.Camargo Cancer Center, Rua Taguá, 440, São Paulo ZIP Code: 01508-010, Brazil; National Institute of Oncogenomics and Innovation, Brazil.
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17
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Ho JJD, Schatz JH, Uniacke J, Lee S. Jekyll and Hyde: Activating the Hypoxic Translational Machinery. Trends Biochem Sci 2020; 46:171-174. [PMID: 33309326 DOI: 10.1016/j.tibs.2020.11.006] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2020] [Revised: 11/09/2020] [Accepted: 11/12/2020] [Indexed: 12/29/2022]
Abstract
Global translational remodeling has emerged as a principal mechanism of biological adaptation. Oxygen deficiency (hypoxia) disables the basal protein synthesis machinery ('Jekyll') and activates a hypoxic translational architecture ('Hyde') to drive translatome remodeling. Independent from mRNA-level fluctuations, this newer paradigm modernizes a field traditionally dominated by the hypoxia-inducible factor (HIF) transcriptional program.
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Affiliation(s)
- J J David Ho
- Sylvester Comprehensive Cancer Center, Miller School of Medicine, University of Miami, Miami, FL 33136, USA; Division of Hematology, Department of Medicine, Miller School of Medicine, University of Miami, Miami, FL 33136, USA
| | - Jonathan H Schatz
- Sylvester Comprehensive Cancer Center, Miller School of Medicine, University of Miami, Miami, FL 33136, USA; Division of Hematology, Department of Medicine, Miller School of Medicine, University of Miami, Miami, FL 33136, USA
| | - Jim Uniacke
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario N1G 2W1, Canada
| | - Stephen Lee
- Sylvester Comprehensive Cancer Center, Miller School of Medicine, University of Miami, Miami, FL 33136, USA; Department of Biochemistry and Molecular Biology, Miller School of Medicine, University of Miami, Miami, FL 33136, USA.
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18
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Ross JA, Ahn BY, King J, Bressler KR, Senger DL, Thakor N. Eukaryotic initiation factor 5B (eIF5B) regulates temozolomide-mediated apoptosis in brain tumour stem cells (BTSCs). Biochem Cell Biol 2020; 98:647-652. [DOI: 10.1139/bcb-2019-0329] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Glioblastoma multiforme (GBM) is among the deadliest cancers, owing in part to complex inter- and intra-tumor heterogeneity and the presence of a population of stem-like cells called brain tumour stem cells (BTSCs/BTICs). These cancer stem cells survive treatment and confer resistance to the current therapies — namely, radiation and the chemotherapeutic, temozolomide (TMZ). TMZ induces cell death by alkylating DNA, and BTSCs resist this mechanism via a robust DNA damage response. Hence, recent studies aimed to sensitize BTSCs to TMZ using combination therapy, such as inhibition of DNA repair machinery. We have previously demonstrated in established GBM cell lines that eukaryotic initiation factor 5B (eIF5B) promotes the translation of pro-survival and anti-apoptotic proteins. Consequently, silencing eIF5B sensitizes these cells to TRAIL-induced apoptosis. However, established cell lines do not always recapitulate the features of human glioma. Therefore, we investigated this mechanism in patient-derived BTSCs. We show that silencing eIF5B leads to increased TMZ sensitivity in two BTSC lines: BT25 and BT48. Depletion of eIF5B decreases the levels of anti-apoptotic proteins in BT48 and sensitizes these cells to TMZ-induced activation of caspase-3, cleavage of PARP, and apoptosis. We suggest that eIF5B represents a rational target to sensitize GBM tumors to the current standard-of-care.
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Affiliation(s)
- Joseph A. Ross
- Alberta RNA Research and Training Institute, Department of Chemistry and Biochemistry, University of Lethbridge, Lethbridge, Alberta, Canada
| | - Bo Young Ahn
- Arnie Charbonneau Cancer Institute, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Jennifer King
- Arnie Charbonneau Cancer Institute, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Kamiko R. Bressler
- Alberta RNA Research and Training Institute, Department of Chemistry and Biochemistry, University of Lethbridge, Lethbridge, Alberta, Canada
| | - Donna L. Senger
- Arnie Charbonneau Cancer Institute, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
- Clark H. Smith Brain Tumour Centre, University of Calgary, Calgary, Alberta, Canada
- Department of Oncology, University of Calgary, Calgary, Alberta, Canada
| | - Nehal Thakor
- Alberta RNA Research and Training Institute, Department of Chemistry and Biochemistry, University of Lethbridge, Lethbridge, Alberta, Canada
- Arnie Charbonneau Cancer Institute, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
- Canadian Centre for Behavioral Neuroscience, Department of Neuroscience, University of Lethbridge, Lethbridge, Alberta, Canada
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19
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Balukoff NC, Ho JJD, Theodoridis PR, Wang M, Bokros M, Llanio LM, Krieger JR, Schatz JH, Lee S. A translational program that suppresses metabolism to shield the genome. Nat Commun 2020; 11:5755. [PMID: 33188200 PMCID: PMC7666154 DOI: 10.1038/s41467-020-19602-2] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2019] [Accepted: 10/22/2020] [Indexed: 12/22/2022] Open
Abstract
Translatome reprogramming is a primary determinant of protein levels during stimuli adaptation. This raises the question: what are the translatome remodelers that reprogram protein output to activate biochemical adaptations. Here, we identify a translational pathway that represses metabolism to safeguard genome integrity. A system-wide MATRIX survey identified the ancient eIF5A as a pH-regulated translation factor that responds to fermentation-induced acidosis. TMT-pulse-SILAC analysis identified several pH-dependent proteins, including the mTORC1 suppressor Tsc2 and the longevity regulator Sirt1. Sirt1 operates as a pH-sensor that deacetylates nuclear eIF5A during anaerobiosis, enabling the cytoplasmic export of eIF5A/Tsc2 mRNA complexes for translational engagement. Tsc2 induction inhibits mTORC1 to suppress cellular metabolism and prevent acidosis-induced DNA damage. Depletion of eIF5A or Tsc2 leads to metabolic re-initiation and proliferation, but at the expense of incurring substantial DNA damage. We suggest that eIF5A operates as a translatome remodeler that suppresses metabolism to shield the genome.
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Affiliation(s)
- Nathan C Balukoff
- Department of Biochemistry and Molecular Biology, Miller School of Medicine, University of Miami, Miami, FL, 33136, USA
- Sylvester Comprehensive Cancer Center, Miller School of Medicine, University of Miami, Miami, FL, 33136, USA
| | - J J David Ho
- Department of Biochemistry and Molecular Biology, Miller School of Medicine, University of Miami, Miami, FL, 33136, USA
- Sylvester Comprehensive Cancer Center, Miller School of Medicine, University of Miami, Miami, FL, 33136, USA
- Division of Hematology, Department of Medicine, Miller School of Medicine, University of Miami, Miami, FL, 33136, USA
| | - Phaedra R Theodoridis
- Department of Biochemistry and Molecular Biology, Miller School of Medicine, University of Miami, Miami, FL, 33136, USA
- Sylvester Comprehensive Cancer Center, Miller School of Medicine, University of Miami, Miami, FL, 33136, USA
| | - Miling Wang
- Department of Biochemistry and Molecular Biology, Miller School of Medicine, University of Miami, Miami, FL, 33136, USA
- Sylvester Comprehensive Cancer Center, Miller School of Medicine, University of Miami, Miami, FL, 33136, USA
| | - Michael Bokros
- Department of Biochemistry and Molecular Biology, Miller School of Medicine, University of Miami, Miami, FL, 33136, USA
- Sylvester Comprehensive Cancer Center, Miller School of Medicine, University of Miami, Miami, FL, 33136, USA
| | - Lis M Llanio
- Department of Biochemistry and Molecular Biology, Miller School of Medicine, University of Miami, Miami, FL, 33136, USA
| | - Jonathan R Krieger
- The SickKids Proteomics, Analytics, Robotics & Chemical Biology Centre (SPARC Biocentre), The Hospital for Sick Children, Toronto, ON, M5G 1×8, Canada
- Bioinformatics Solutions Inc., Waterloo, ON, N2L 6J2, Canada
| | - Jonathan H Schatz
- Sylvester Comprehensive Cancer Center, Miller School of Medicine, University of Miami, Miami, FL, 33136, USA
- Division of Hematology, Department of Medicine, Miller School of Medicine, University of Miami, Miami, FL, 33136, USA
| | - Stephen Lee
- Department of Biochemistry and Molecular Biology, Miller School of Medicine, University of Miami, Miami, FL, 33136, USA.
- Sylvester Comprehensive Cancer Center, Miller School of Medicine, University of Miami, Miami, FL, 33136, USA.
- Department of Urology, Miller School of Medicine, University of Miami, Miami, FL, 33136, USA.
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20
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Schmitt E, Coureux PD, Kazan R, Bourgeois G, Lazennec-Schurdevin C, Mechulam Y. Recent Advances in Archaeal Translation Initiation. Front Microbiol 2020; 11:584152. [PMID: 33072057 PMCID: PMC7531240 DOI: 10.3389/fmicb.2020.584152] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2020] [Accepted: 08/24/2020] [Indexed: 12/20/2022] Open
Abstract
Translation initiation (TI) allows accurate selection of the initiation codon on a messenger RNA (mRNA) and defines the reading frame. In all domains of life, translation initiation generally occurs within a macromolecular complex made up of the small ribosomal subunit, the mRNA, a specialized methionylated initiator tRNA, and translation initiation factors (IFs). Once the start codon is selected at the P site of the ribosome and the large subunit is associated, the IFs are released and a ribosome competent for elongation is formed. However, even if the general principles are the same in the three domains of life, the molecular mechanisms are different in bacteria, eukaryotes, and archaea and may also vary depending on the mRNA. Because TI mechanisms have evolved lately, their studies bring important information about the evolutionary relationships between extant organisms. In this context, recent structural data on ribosomal complexes and genome-wide studies are particularly valuable. This review focuses on archaeal translation initiation highlighting its relationships with either the eukaryotic or the bacterial world. Eukaryotic features of the archaeal small ribosomal subunit are presented. Ribosome evolution and TI mechanisms diversity in archaeal branches are discussed. Next, the use of leaderless mRNAs and that of leadered mRNAs having Shine-Dalgarno sequences is analyzed. Finally, the current knowledge on TI mechanisms of SD-leadered and leaderless mRNAs is detailed.
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Affiliation(s)
- Emmanuelle Schmitt
- Laboratoire de Biologie Structurale de la Cellule, BIOC, Ecole Polytechnique, CNRS-UMR7654, Institut Polytechnique de Paris, Palaiseau, France
| | - Pierre-Damien Coureux
- Laboratoire de Biologie Structurale de la Cellule, BIOC, Ecole Polytechnique, CNRS-UMR7654, Institut Polytechnique de Paris, Palaiseau, France
| | - Ramy Kazan
- Laboratoire de Biologie Structurale de la Cellule, BIOC, Ecole Polytechnique, CNRS-UMR7654, Institut Polytechnique de Paris, Palaiseau, France
| | - Gabrielle Bourgeois
- Laboratoire de Biologie Structurale de la Cellule, BIOC, Ecole Polytechnique, CNRS-UMR7654, Institut Polytechnique de Paris, Palaiseau, France
| | - Christine Lazennec-Schurdevin
- Laboratoire de Biologie Structurale de la Cellule, BIOC, Ecole Polytechnique, CNRS-UMR7654, Institut Polytechnique de Paris, Palaiseau, France
| | - Yves Mechulam
- Laboratoire de Biologie Structurale de la Cellule, BIOC, Ecole Polytechnique, CNRS-UMR7654, Institut Polytechnique de Paris, Palaiseau, France
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21
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Ho JJD, Balukoff NC, Theodoridis PR, Wang M, Krieger JR, Schatz JH, Lee S. A network of RNA-binding proteins controls translation efficiency to activate anaerobic metabolism. Nat Commun 2020; 11:2677. [PMID: 32472050 PMCID: PMC7260222 DOI: 10.1038/s41467-020-16504-1] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2019] [Accepted: 04/30/2020] [Indexed: 01/30/2023] Open
Abstract
Protein expression evolves under greater evolutionary constraint than mRNA levels, and translation efficiency represents a primary determinant of protein levels during stimuli adaptation. This raises the question as to the translatome remodelers that titrate protein output from mRNA populations. Here, we uncover a network of RNA-binding proteins (RBPs) that enhances the translation efficiency of glycolytic proteins in cells responding to oxygen deprivation. A system-wide proteomic survey of translational engagement identifies a family of oxygen-regulated RBPs that functions as a switch of glycolytic intensity. Tandem mass tag-pulse SILAC (TMT-pSILAC) and RNA sequencing reveals that each RBP controls a unique but overlapping portfolio of hypoxic responsive proteins. These RBPs collaborate with the hypoxic protein synthesis apparatus, operating as a translation efficiency checkpoint that integrates upstream mRNA signals to activate anaerobic metabolism. This system allows anoxia-resistant animals and mammalian cells to initiate anaerobic glycolysis and survive hypoxia. We suggest that an oxygen-sensitive RBP cluster controls anaerobic metabolism to confer hypoxia tolerance. mRNA translation efficiency is regulated in response to stimuli. Here the authors employ mass spectrometry analysis of ribosome fractions and show that under hypoxia, oxygen-sensitive RNA binding proteins enhance the translation efficiency of glycolysis pathway transcripts.
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Affiliation(s)
- J J David Ho
- Department of Biochemistry and Molecular Biology, Miller School of Medicine, University of Miami, Miami, FL, 33136, USA.,Sylvester Comprehensive Cancer Center, Miller School of Medicine, University of Miami, Miami, FL, 33136, USA.,Division of Hematology, Department of Medicine, Miller School of Medicine, University of Miami, Miami, FL, 33136, USA
| | - Nathan C Balukoff
- Department of Biochemistry and Molecular Biology, Miller School of Medicine, University of Miami, Miami, FL, 33136, USA.,Sylvester Comprehensive Cancer Center, Miller School of Medicine, University of Miami, Miami, FL, 33136, USA
| | - Phaedra R Theodoridis
- Department of Biochemistry and Molecular Biology, Miller School of Medicine, University of Miami, Miami, FL, 33136, USA.,Sylvester Comprehensive Cancer Center, Miller School of Medicine, University of Miami, Miami, FL, 33136, USA
| | - Miling Wang
- Department of Biochemistry and Molecular Biology, Miller School of Medicine, University of Miami, Miami, FL, 33136, USA.,Sylvester Comprehensive Cancer Center, Miller School of Medicine, University of Miami, Miami, FL, 33136, USA
| | - Jonathan R Krieger
- The SickKids Proteomics, Analytics, Robotics & Chemical Biology Centre (SPARC Biocentre), The Hospital for Sick Children, Toronto, ON, M5G 1X8, Canada.,Bioinformatics Solutions Inc., Waterloo, ON, N2L 6J2, Canada
| | - Jonathan H Schatz
- Sylvester Comprehensive Cancer Center, Miller School of Medicine, University of Miami, Miami, FL, 33136, USA.,Division of Hematology, Department of Medicine, Miller School of Medicine, University of Miami, Miami, FL, 33136, USA
| | - Stephen Lee
- Department of Biochemistry and Molecular Biology, Miller School of Medicine, University of Miami, Miami, FL, 33136, USA. .,Sylvester Comprehensive Cancer Center, Miller School of Medicine, University of Miami, Miami, FL, 33136, USA. .,Department of Urology, Miller School of Medicine, University of Miami, Miami, 33136, USA.
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22
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Suresh S, Chen B, Zhu J, Golden RJ, Lu C, Evers BM, Novaresi N, Smith B, Zhan X, Schmid V, Jun S, Karacz CM, Peyton M, Zhong L, Wen Z, Sathe AA, Xing C, Behrens C, Wistuba II, Xiao G, Xie Y, Fu YX, Minna JD, Mendell JT, O'Donnell KA. eIF5B drives integrated stress response-dependent translation of PD-L1 in lung cancer. NATURE CANCER 2020; 1:533-545. [PMID: 32984844 PMCID: PMC7511089 DOI: 10.1038/s43018-020-0056-0] [Citation(s) in RCA: 67] [Impact Index Per Article: 16.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/03/2019] [Accepted: 03/17/2020] [Indexed: 12/24/2022]
Abstract
Cancer cells express high levels of PD-L1, a ligand of the PD-1 receptor on T cells, allowing tumors to suppress T cell activity. Clinical trials utilizing antibodies that disrupt the PD-1/PD-L1 checkpoint have yielded remarkable results, with anti-PD-1 immunotherapy approved as first-line therapy for lung cancer patients. We used CRISPR-based screening to identify regulators of PD-L1 in human lung cancer cells, revealing potent induction of PD-L1 upon disruption of heme biosynthesis. Impairment of heme production activates the integrated stress response (ISR), allowing bypass of inhibitory upstream open reading frames in the PD-L1 5' UTR, resulting in enhanced PD-L1 translation and suppression of anti-tumor immunity. We demonstrated that ISR-dependent PD-L1 translation requires the translation initiation factor eIF5B. eIF5B overexpression, which is frequent in lung adenocarcinomas and associated with poor prognosis, is sufficient to induce PD-L1. These findings illuminate mechanisms of immune checkpoint activation and identify targets for therapeutic intervention.
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Affiliation(s)
- Shruthy Suresh
- Department of Molecular Biology, UT Southwestern Medical Center, Dallas, TX, USA
| | - BeiBei Chen
- Quantitative Biomedical Research Center, UT Southwestern Medical Center, Dallas, TX, USA
- Department of Population and Data Sciences, UT Southwestern Medical Center, Dallas, TX, USA
| | - Jingfei Zhu
- Department of Molecular Biology, UT Southwestern Medical Center, Dallas, TX, USA
| | - Ryan J Golden
- Department of Molecular Biology, UT Southwestern Medical Center, Dallas, TX, USA
- Department of Pathology and Laboratory Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Changzheng Lu
- Department of Pathology, UT Southwestern Medical Center, Dallas, TX, United States
| | - Bret M Evers
- Department of Pathology, UT Southwestern Medical Center, Dallas, TX, United States
| | - Nicole Novaresi
- Department of Molecular Biology, UT Southwestern Medical Center, Dallas, TX, USA
| | - Bethany Smith
- Department of Molecular Biology, UT Southwestern Medical Center, Dallas, TX, USA
| | - Xiaowei Zhan
- Department of Population and Data Sciences, UT Southwestern Medical Center, Dallas, TX, USA
| | - Vanessa Schmid
- Eugene McDermott Center for Human Growth and Development, UT Southwestern Medical Center, Dallas, TX, USA
| | - Sojeong Jun
- Children's Research Institute, UT Southwestern Medical Center, Dallas, TX, USA
| | - Chelsea M Karacz
- Department of Pathology, UT Southwestern Medical Center, Dallas, TX, United States
| | - Michael Peyton
- Harold C. Simmons Comprehensive Cancer Center, UT Southwestern Medical Center, Dallas, TX, USA
- Hamon Center for Therapeutic Oncology Research, UT Southwestern Medical Center, Dallas, TX, USA
| | - Lin Zhong
- Department of Population and Data Sciences, UT Southwestern Medical Center, Dallas, TX, USA
| | - Zhuoyu Wen
- Department of Population and Data Sciences, UT Southwestern Medical Center, Dallas, TX, USA
| | - Adwait Amod Sathe
- Eugene McDermott Center for Human Growth and Development, UT Southwestern Medical Center, Dallas, TX, USA
| | - Chao Xing
- Department of Population and Data Sciences, UT Southwestern Medical Center, Dallas, TX, USA
- Eugene McDermott Center for Human Growth and Development, UT Southwestern Medical Center, Dallas, TX, USA
| | - Carmen Behrens
- Department of Thoracic Head and Neck Medical Oncology, MD Anderson Cancer Center, Houston, TX, USA
| | - Ignacio I Wistuba
- Department of Thoracic Head and Neck Medical Oncology, MD Anderson Cancer Center, Houston, TX, USA
- Department of Translational Molecular Pathology, MD Anderson Cancer Center, Houston, TX, USA
| | - Guanghua Xiao
- Department of Population and Data Sciences, UT Southwestern Medical Center, Dallas, TX, USA
| | - Yang Xie
- Quantitative Biomedical Research Center, UT Southwestern Medical Center, Dallas, TX, USA
- Department of Population and Data Sciences, UT Southwestern Medical Center, Dallas, TX, USA
| | - Yang-Xin Fu
- Department of Pathology, UT Southwestern Medical Center, Dallas, TX, United States
| | - John D Minna
- Harold C. Simmons Comprehensive Cancer Center, UT Southwestern Medical Center, Dallas, TX, USA
- Hamon Center for Therapeutic Oncology Research, UT Southwestern Medical Center, Dallas, TX, USA
- Department of Pharmacology, UT Southwestern Medical Center, Dallas, TX, USA
| | - Joshua T Mendell
- Department of Molecular Biology, UT Southwestern Medical Center, Dallas, TX, USA
- Harold C. Simmons Comprehensive Cancer Center, UT Southwestern Medical Center, Dallas, TX, USA
- Hamon Center for Regenerative Medicine, UT Southwestern Medical Center, Dallas, TX, USA
- Howard Hughes Medical Institute, Chevy Chase, MD, USA
| | - Kathryn A O'Donnell
- Department of Molecular Biology, UT Southwestern Medical Center, Dallas, TX, USA.
- Harold C. Simmons Comprehensive Cancer Center, UT Southwestern Medical Center, Dallas, TX, USA.
- Hamon Center for Regenerative Medicine, UT Southwestern Medical Center, Dallas, TX, USA.
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23
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Läsche M, Emons G, Gründker C. Shedding New Light on Cancer Metabolism: A Metabolic Tightrope Between Life and Death. Front Oncol 2020; 10:409. [PMID: 32300553 PMCID: PMC7145406 DOI: 10.3389/fonc.2020.00409] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2020] [Accepted: 03/09/2020] [Indexed: 12/13/2022] Open
Abstract
Since the earliest findings of Otto Warburg, who discovered the first metabolic differences between lactate production of cancer cells and non-malignant tissues in the 1920s, much time has passed. He explained the increased lactate levels with dysfunctional mitochondria and aerobic glycolysis despite adequate oxygenation. Meanwhile, we came to know that mitochondria remain instead functional in cancer cells; hence, metabolic drift, rather than being linked to dysfunctional mitochondria, was found to be an active act of direct response of cancer cells to cell proliferation and survival signals. This metabolic drift begins with the use of sugars and the full oxidative phosphorylation via the mitochondrial respiratory chain to form CO2, and it then leads to the formation of lactic acid via partial oxidation. In addition to oncogene-driven metabolic reprogramming, the oncometabolites themselves alter cell signaling and are responsible for differentiation and metastasis of cancer cells. The aberrant metabolism is now considered a major characteristic of cancer within the past 15 years. However, the proliferating anabolic growth of a tumor and its spread to distal sites of the body is not explainable by altered glucose metabolism alone. Since a tumor consists of malignant cells and its tumor microenvironment, it was important for us to understand the bilateral interactions between the primary tumor and its microenvironment and the processes underlying its successful metastasis. We here describe the main metabolic pathways and their implications in tumor progression and metastasis. We also portray that metabolic flexibility determines the fate of the cancer cell and ultimately the patient. This flexibility must be taken into account when deciding on a therapy, since singular cancer therapies only shift the metabolism to a different alternative path and create resistance to the medication used. As with Otto Warburg in his days, we primarily focused on the metabolism of mitochondria when dealing with this scientific question.
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Affiliation(s)
- Matthias Läsche
- Department of Gynecology and Obstetrics, University Medicine Göttingen, Göttingen, Germany
| | - Günter Emons
- Department of Gynecology and Obstetrics, University Medicine Göttingen, Göttingen, Germany
| | - Carsten Gründker
- Department of Gynecology and Obstetrics, University Medicine Göttingen, Göttingen, Germany
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24
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Brumwell A, Fell L, Obress L, Uniacke J. Hypoxia influences polysome distribution of human ribosomal protein S12 and alternative splicing of ribosomal protein mRNAs. RNA (NEW YORK, N.Y.) 2020; 26:361-371. [PMID: 31911497 PMCID: PMC7025504 DOI: 10.1261/rna.070318.119] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/08/2019] [Accepted: 01/02/2020] [Indexed: 06/10/2023]
Abstract
Ribosomes were once considered static in their composition because of their essential role in protein synthesis and kingdom-wide conservation. The existence of tolerated mutations in select ribosomal proteins (RPs), such as in Diamond-Blackfan anemia, is evidence that not all ribosome components are essential. Heterogeneity in the protein composition of eukaryotic ribosomes is an emerging concept with evidence that different pools of ribosomes exist with transcript-specificity. Here, we show that the polysome association of ribosomal proteins is altered by low oxygen (hypoxia), a feature of the tumor microenvironment, in human cells. We quantified ribosomal protein abundance in actively translating polysomes of normoxic and hypoxic HEK293 cells by tandem mass tags mass spectrometry. Our data suggest that RPS12 (eS12) is enriched in hypoxic monosomes, which increases the heavy polysome association of structured transcripts APAF-1 and XIAP. Furthermore, hypoxia induced five alternative splicing events within a subset of RP mRNAs in cell lines. One of these events in RPS24 (eS24 protein) alters the coding sequence to produce two protein isoforms that can incorporate into ribosomes. This splicing event is greatly induced in spheroids and correlates with tumor hypoxia in human prostate cancer. Our data suggest that hypoxia may influence the composition of the human ribosome through changes in RP incorporation and the production of hypoxia-specific RP isoforms.
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Affiliation(s)
- Andrea Brumwell
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario N1G 2W1, Canada
| | - Leslie Fell
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario N1G 2W1, Canada
| | - Lindsay Obress
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario N1G 2W1, Canada
| | - James Uniacke
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario N1G 2W1, Canada
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25
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Chen HH, Tarn WY. uORF-mediated translational control: recently elucidated mechanisms and implications in cancer. RNA Biol 2019; 16:1327-1338. [PMID: 31234713 DOI: 10.1080/15476286.2019.1632634] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Protein synthesis is tightly regulated, and its dysregulation can contribute to the pathology of various diseases, including cancer. Increased or selective translation of mRNAs can promote cancer cell proliferation, metastasis and tumor expansion. Translational control is one of the most important means for cells to quickly adapt to environmental stresses. Adaptive translation involves various alternative mechanisms of translation initiation. Upstream open reading frames (uORFs) serve as a major regulator of stress-responsive translational control. Since recent advances in omics technologies including ribo-seq have expanded our knowledge of translation, we discuss emerging mechanisms for uORF-mediated translation regulation and its impact on cancer cell biology. A better understanding of dysregulated translational control of uORFs in cancer would facilitate the development of new strategies for cancer therapy.
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Affiliation(s)
- Hung-Hsi Chen
- Institute of Biomedical Sciences, Academia Sinica , Taipei , Taiwan
| | - Woan-Yuh Tarn
- Institute of Biomedical Sciences, Academia Sinica , Taipei , Taiwan
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26
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Start Codon Recognition in Eukaryotic and Archaeal Translation Initiation: A Common Structural Core. Int J Mol Sci 2019; 20:ijms20040939. [PMID: 30795538 PMCID: PMC6412873 DOI: 10.3390/ijms20040939] [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: 12/05/2018] [Revised: 02/11/2019] [Accepted: 02/13/2019] [Indexed: 01/12/2023] Open
Abstract
Understanding molecular mechanisms of ribosomal translation sheds light on the emergence and evolution of protein synthesis in the three domains of life. Universally, ribosomal translation is described in three steps: initiation, elongation and termination. During initiation, a macromolecular complex assembled around the small ribosomal subunit selects the start codon on the mRNA and defines the open reading frame. In this review, we focus on the comparison of start codon selection mechanisms in eukaryotes and archaea. Eukaryotic translation initiation is a very complicated process, involving many initiation factors. The most widespread mechanism for the discovery of the start codon is the scanning of the mRNA by a pre-initiation complex until the first AUG codon in a correct context is found. In archaea, long-range scanning does not occur because of the presence of Shine-Dalgarno (SD) sequences or of short 5′ untranslated regions. However, archaeal and eukaryotic translation initiations have three initiation factors in common: e/aIF1, e/aIF1A and e/aIF2 are directly involved in the selection of the start codon. Therefore, the idea that these archaeal and eukaryotic factors fulfill similar functions within a common structural ribosomal core complex has emerged. A divergence between eukaryotic and archaeal factors allowed for the adaptation to the long-range scanning process versus the SD mediated prepositioning of the ribosome.
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27
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Ross JA, Dungen KV, Bressler KR, Fredriksen M, Khandige Sharma D, Balasingam N, Thakor N. Eukaryotic initiation factor 5B (eIF5B) provides a critical cell survival switch to glioblastoma cells via regulation of apoptosis. Cell Death Dis 2019; 10:57. [PMID: 30670698 PMCID: PMC6342974 DOI: 10.1038/s41419-018-1283-5] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2018] [Revised: 11/29/2018] [Accepted: 12/07/2018] [Indexed: 12/26/2022]
Abstract
Physiological stress conditions attenuate global mRNA translation via modifications of key eukaryotic initiation factors. However, non-canonical translation initiation mechanisms allow cap-independent translation of certain mRNAs. We have previously demonstrated that eIF5B promotes cap-independent translation of the mRNA encoding the antiapoptotic factor, XIAP, during cellular stress. Here, we show that depletion of eIF5B sensitizes glioblastoma multiforme cells to TRAIL-induced apoptosis by a pathway involving caspases-8, −9, and −7, with no significant effect on cell cycle progression. eIF5B promotes evasion of apoptosis by promoting the translation of several IRES-containing mRNAs, encoding the antiapoptotic proteins XIAP, Bcl-xL, cIAP1, and c-FLIPS. We also show that eIF5B promotes translation of nuclear factor erythroid 2-related factor 2 and suggest that reactive oxygen species contribute to increased apoptosis under conditions of eIF5B depletion. Finally, eIF5B depletion leads to decreased activation of the canonical NF-κB pathway. Taken together, our data suggest that eIF5B represents a regulatory node, allowing cancer cells to evade apoptosis by promoting the translation of pro-survival proteins from IRES-containing mRNAs.
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Affiliation(s)
- Joseph A Ross
- Department of Chemistry and Biochemistry, University of Lethbridge, 4401 University Drive W, Lethbridge, AB, T1K 3M4, Canada
| | - Keiran Vanden Dungen
- Department of Chemistry and Biochemistry, University of Lethbridge, 4401 University Drive W, Lethbridge, AB, T1K 3M4, Canada
| | - Kamiko R Bressler
- Department of Chemistry and Biochemistry, University of Lethbridge, 4401 University Drive W, Lethbridge, AB, T1K 3M4, Canada
| | - Mikayla Fredriksen
- Department of Chemistry and Biochemistry, University of Lethbridge, 4401 University Drive W, Lethbridge, AB, T1K 3M4, Canada
| | - Divya Khandige Sharma
- Department of Chemistry and Biochemistry, University of Lethbridge, 4401 University Drive W, Lethbridge, AB, T1K 3M4, Canada
| | - Nirujah Balasingam
- Department of Chemistry and Biochemistry, University of Lethbridge, 4401 University Drive W, Lethbridge, AB, T1K 3M4, Canada
| | - Nehal Thakor
- Department of Chemistry and Biochemistry, University of Lethbridge, 4401 University Drive W, Lethbridge, AB, T1K 3M4, Canada. .,Canadian Centre for Behavioral Neuroscience (CCBN), Department of Neuroscience, University of Lethbridge, 4401 University Drive W, Lethbridge, AB, T1K 3M4, Canada. .,Arnie Charbonneau Cancer Institute, Cumming School of Medicine, University of Calgary, 3280 Hospital Drive NW, Calgary, AB, T2N 4Z6, Canada.
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28
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Ross JA, Bressler KR, Thakor N. Eukaryotic Initiation Factor 5B (eIF5B) Cooperates with eIF1A and eIF5 to Facilitate uORF2-Mediated Repression of ATF4 Translation. Int J Mol Sci 2018; 19:E4032. [PMID: 30551605 PMCID: PMC6321046 DOI: 10.3390/ijms19124032] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2018] [Revised: 12/08/2018] [Accepted: 12/10/2018] [Indexed: 12/20/2022] Open
Abstract
A variety of cellular stresses lead to global translation attenuation due to phosphorylation of the alpha subunit of eukaryotic initiation factor 2 (eIF2), which decreases the availability of the eIF2-GTP-Met-tRNAi ternary complex. However, a subset of mRNAs continues to be translated by non-canonical mechanisms under these conditions. In fact, although translation initiation of activating transcription factor 4 (ATF4) is normally repressed by an upstream open reading frame (uORF), a decreased availability of ternary complex leads to increased translation of the main ATF4-coding ORF. We show here that siRNA-mediated depletion of eIF5B-which can substitute for eIF2 in delivering Met-tRNAi-leads to increased levels of ATF4 protein in mammalian cells. This de-repression is not due to phosphorylation of eIF2α under conditions of eIF5B depletion. Although eIF5B depletion leads to a modest increase in the steady-state levels of ATF4 mRNA, we show by polysome profiling that the depletion of eIF5B enhances ATF4 expression primarily at the level of translation. Moreover, eIF5B silencing increases the expression of an ATF4-luciferase translational reporter by a mechanism requiring the repressive uORF2. Further experiments suggest that eIF5B cooperates with eIF1A and eIF5, but not eIF2A, to facilitate the uORF2-mediated repression of ATF4 translation.
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Affiliation(s)
- Joseph A Ross
- Department of Chemistry and Biochemistry, University of Lethbridge, 4401 University Drive W, Lethbridge, AB T1K 3M4, Canada.
| | - Kamiko R Bressler
- Department of Chemistry and Biochemistry, University of Lethbridge, 4401 University Drive W, Lethbridge, AB T1K 3M4, Canada.
| | - Nehal Thakor
- Department of Chemistry and Biochemistry, University of Lethbridge, 4401 University Drive W, Lethbridge, AB T1K 3M4, Canada.
- Canadian Centre for Behavioral Neuroscience (CCBN), Department of Neuroscience, University of Lethbridge, 4401 University Drive W, Lethbridge, AB T1K 3M4, Canada.
- Arnie Charbonneau Cancer Institute, Cumming School of Medicine, University of Calgary, 3280 Hospital Drive NW, Calgary, AB T2N 4Z6, Canada.
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29
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Stonyte V, Boye E, Grallert B. Regulation of global translation during the cell cycle. J Cell Sci 2018; 131:jcs.220327. [PMID: 30072440 DOI: 10.1242/jcs.220327] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2018] [Accepted: 07/20/2018] [Indexed: 01/10/2023] Open
Abstract
It is generally accepted that global translation varies during the cell cycle and is low during mitosis. However, addressing this issue is challenging because it involves cell synchronization, which evokes stress responses that, in turn, affect translation rates. Here, we have used two approaches to measure global translation rates in different cell-cycle phases. First, synchrony in different cell-cycle phases was obtained involving the same stress, by using temperature-sensitive mutants. Second, translation and DNA content were measured by flow cytometry in exponentially growing, single cells. We found no major variation in global translation rates through the cell cycle in either fission yeast or mammalian cells. We also measured phosphorylation of eukaryotic initiation factor-2α, an event that is thought to downregulate global translation in mitosis. In contrast with the prevailing view, eIF2α phosphorylation correlated poorly with downregulation of global translation and ectopically induced eIF2α phosphorylation inhibited global translation only at high levels.
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Affiliation(s)
- Vilte Stonyte
- Department of Radiation Biology, Institute for Cancer Research, Montebello, 0379 Oslo University Hospital, Oslo, Norway
| | - Erik Boye
- Department of Radiation Biology, Institute for Cancer Research, Montebello, 0379 Oslo University Hospital, Oslo, Norway
| | - Beáta Grallert
- Department of Radiation Biology, Institute for Cancer Research, Montebello, 0379 Oslo University Hospital, Oslo, Norway
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30
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Battling for Ribosomes: Translational Control at the Forefront of the Antiviral Response. J Mol Biol 2018; 430:1965-1992. [PMID: 29746850 DOI: 10.1016/j.jmb.2018.04.040] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2018] [Revised: 04/24/2018] [Accepted: 04/27/2018] [Indexed: 01/05/2023]
Abstract
In the early stages of infection, gaining control of the cellular protein synthesis machinery including its ribosomes is the ultimate combat objective for a virus. To successfully replicate, viruses unequivocally need to usurp and redeploy this machinery for translation of their own mRNA. In response, the host triggers global shutdown of translation while paradoxically allowing swift synthesis of antiviral proteins as a strategy to limit collateral damage. This fundamental conflict at the level of translational control defines the outcome of infection. As part of this special issue on molecular mechanisms of early virus-host cell interactions, we review the current state of knowledge regarding translational control during viral infection with specific emphasis on protein kinase RNA-activated and mammalian target of rapamycin-mediated mechanisms. We also describe recent technological advances that will allow unprecedented insight into how viruses and host cells battle for ribosomes.
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