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Afroz T, Skrisovska L, Belloc E, Guillén-Boixet J, Méndez R, Allain FHT. A fly trap mechanism provides sequence-specific RNA recognition by CPEB proteins. Genes Dev 2014; 28:1498-514. [PMID: 24990967 PMCID: PMC4083092 DOI: 10.1101/gad.241133.114] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
How CPEB RNA-binding proteins regulate cytoplasmic polyadenylation and translation is poorly understood. Allain and colleagues report the structures of the tandem RNA recognition motifs (RRMs) of two human paralogs (CPEB1 and CPEB4) in their free and RNA-bound states. Structural and functional studies reveal how RNA binding by CPEB proteins leads to an optimal positioning of the N-terminal and zinc-binding domains at the 3′ UTR, which favors the nucleation of ribonucleoprotein complexes for translation regulation. This study provides the molecular basis for the translational regulatory circuit established by CPEB proteins. Cytoplasmic changes in polyA tail length is a key mechanism of translational control and is implicated in germline development, synaptic plasticity, cellular proliferation, senescence, and cancer progression. The presence of a U-rich cytoplasmic polyadenylation element (CPE) in the 3′ untranslated regions (UTRs) of the responding mRNAs gives them the selectivity to be regulated by the CPE-binding (CPEB) family of proteins, which recognizes RNA via the tandem RNA recognition motifs (RRMs). Here we report the solution structures of the tandem RRMs of two human paralogs (CPEB1 and CPEB4) in their free and RNA-bound states. The structures reveal an unprecedented arrangement of RRMs in the free state that undergo an original closure motion upon RNA binding that ensures high fidelity. Structural and functional characterization of the ZZ domain (zinc-binding domain) of CPEB1 suggests a role in both protein–protein and protein–RNA interactions. Together with functional studies, the structures reveal how RNA binding by CPEB proteins leads to an optimal positioning of the N-terminal and ZZ domains at the 3′ UTR, which favors the nucleation of the functional ribonucleoprotein complexes for translation regulation.
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Affiliation(s)
- Tariq Afroz
- Institute of Molecular Biology and Biophysics, Eidgenössische Technische Hochschule (ETH) Zurich, CH-8093 Zürich, Switzerland
| | - Lenka Skrisovska
- Institute of Molecular Biology and Biophysics, Eidgenössische Technische Hochschule (ETH) Zurich, CH-8093 Zürich, Switzerland
| | - Eulàlia Belloc
- Institute for Research in Biomedicine, 08028 Barcelona, Spain
| | | | - Raúl Méndez
- Institute for Research in Biomedicine, 08028 Barcelona, Spain; Institució Catalana de Recerca i Estudis Avançats (ICREA), 08010 Barcelona, Spain
| | - Frédéric H-T Allain
- Institute of Molecular Biology and Biophysics, Eidgenössische Technische Hochschule (ETH) Zurich, CH-8093 Zürich, Switzerland
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102
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Schelhorn C, Gordon JMB, Ruiz L, Alguacil J, Pedroso E, Macias MJ. RNA recognition and self-association of CPEB4 is mediated by its tandem RRM domains. Nucleic Acids Res 2014; 42:10185-95. [PMID: 25081215 PMCID: PMC4150798 DOI: 10.1093/nar/gku700] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2014] [Revised: 07/11/2014] [Accepted: 07/19/2014] [Indexed: 11/12/2022] Open
Abstract
Cytoplasmic polyadenylation is regulated by the interaction of the cytoplasmic polyadenylation element binding proteins (CPEB) with cytoplasmic polyadenylation element (CPE) containing mRNAs. The CPEB family comprises four paralogs, CPEB1-4, each composed of a variable N-terminal region, two RNA recognition motif (RRM) and a C-terminal ZZ-domain. We have characterized the RRM domains of CPEB4 and their binding properties using a combination of biochemical, biophysical and NMR techniques. Isothermal titration calorimetry, NMR and electrophoretic mobility shift assay experiments demonstrate that both the RRM domains are required for an optimal CPE interaction and the presence of either one or two adenosines in the two most commonly used consensus CPE motifs has little effect on the affinity of the interaction. Both the single RRM1 and the tandem RRM1-RRM2 have the ability to dimerize, although representing a minor population. Self-association does not affect the proteins' ability to interact with RNA as demonstrated by ion mobility-mass spectrometry. Chemical shift effects measured by NMR of the apo forms of the RRM1-RRM2 samples indicate that the two domains are orientated toward each other. NMR titration experiments show that residues on the β-sheet surface on RRM1 and at the C-terminus of RRM2 are affected upon RNA binding. We propose a model of the CPEB4 RRM1-RRM2-CPE complex that illustrates the experimental data.
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Affiliation(s)
- Constanze Schelhorn
- Institute for Research in Biomedicine (IRB Barcelona), Baldiri Reixac 10, Barcelona 08028, Spain
| | - James M B Gordon
- Institute for Research in Biomedicine (IRB Barcelona), Baldiri Reixac 10, Barcelona 08028, Spain
| | - Lidia Ruiz
- Institute for Research in Biomedicine (IRB Barcelona), Baldiri Reixac 10, Barcelona 08028, Spain
| | - Javier Alguacil
- Departament de Química Orgànica and IBUB, Universitat de Barcelona, Martí i Franquès 1-11, 08028 Barcelona, Spain
| | - Enrique Pedroso
- Departament de Química Orgànica and IBUB, Universitat de Barcelona, Martí i Franquès 1-11, 08028 Barcelona, Spain
| | - Maria J Macias
- Institute for Research in Biomedicine (IRB Barcelona), Baldiri Reixac 10, Barcelona 08028, Spain Catalan Institution for Research and Advanced Studies (ICREA), Passeig Lluis Companys 23, Barcelona 08010, Spain
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103
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Ivshina M, Lasko P, Richter JD. Cytoplasmic polyadenylation element binding proteins in development, health, and disease. Annu Rev Cell Dev Biol 2014; 30:393-415. [PMID: 25068488 DOI: 10.1146/annurev-cellbio-101011-155831] [Citation(s) in RCA: 154] [Impact Index Per Article: 15.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
The cytoplasmic polyadenylation element binding (CPEB) proteins are sequence-specific mRNA binding proteins that control translation in development, health, and disease. CPEB1, the founding member of this family, has become an important model for illustrating general principles of translational control by cytoplasmic polyadenylation in gametogenesis, cancer etiology, synaptic plasticity, learning, and memory. Although the biological functions of the other members of this protein family in vertebrates are just beginning to emerge, it is already evident that they, too, mediate important processes, such as cancer etiology and higher cognitive function. In Drosophila, the CPEB proteins Orb and Orb2 play key roles in oogenesis and in neuronal function, as do related proteins in Caenorhabditis elegans and Aplysia. We review the biochemical features of the CPEB proteins, discuss their activities in several biological systems, and illustrate how understanding CPEB activity in model organisms has an important impact on neurological disease.
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Affiliation(s)
- Maria Ivshina
- Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, Massachusetts 01605;
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104
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Martínez-Bosch N, Fernández-Barrena MG, Moreno M, Ortiz-Zapater E, Munné-Collado J, Iglesias M, André S, Gabius HJ, Hwang RF, Poirier F, Navas C, Guerra C, Fernández-Zapico ME, Navarro P. Galectin-1 drives pancreatic carcinogenesis through stroma remodeling and Hedgehog signaling activation. Cancer Res 2014; 74:3512-24. [PMID: 24812270 PMCID: PMC4332591 DOI: 10.1158/0008-5472.can-13-3013] [Citation(s) in RCA: 90] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Despite some advances, pancreatic ductal adenocarcinoma (PDAC) remains generally refractory to current treatments. Desmoplastic stroma, a consistent hallmark of PDAC, has emerged as a major source of therapeutic resistance and thus potentially promising targets for improved treatment. The glycan-binding protein galectin-1 (Gal1) is highly expressed in PDAC stroma, but its roles there have not been studied. Here we report functions and molecular pathways of Gal1 that mediate its oncogenic properties in this setting. Genetic ablation of Gal1 in a mouse model of PDAC (EIa-myc mice) dampened tumor progression by inhibiting proliferation, angiogenesis, desmoplasic reaction and by stimulating a tumor-associated immune response, yielding a 20% increase in relative lifesplan. Cellular analyses in vitro and in vivo suggested these effects were mediated through the tumor microenvironment. Importantly, acinar-to-ductal metaplasia, a crucial step for initiation of PDAC, was found to be regulated by Gal1. Mechanistic investigations revealed that Gal1 promoted Hedgehog pathway signaling in PDAC cells and stromal fibroblasts as well as in Ela-myc tumors. Taken together, our findings establish a function for Gal1 in tumor-stroma crosstalk in PDAC and provide a preclinical rationale for Gal1 targeting as a microenvironment-based therapeutic strategy.
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Affiliation(s)
| | - Maite G Fernández-Barrena
- Schulze Center for Novel Therapeutics, Division of Oncology Research, Mayo Clinic, Rochester, Minnesota
| | | | | | - Jessica Munné-Collado
- Authors' Affiliations: Cancer Research Program and Department of Pathology, IMIM (Hospital del Mar Medical Research Institute), Barcelona
| | - Mar Iglesias
- Authors' Affiliations: Cancer Research Program and Department of Pathology, IMIM (Hospital del Mar Medical Research Institute), Barcelona
| | - Sabine André
- Institut für Physiologische Chemie, Tierärztliche Fakultät, Ludwig-Maximilians-Universität, München, Germany; and
| | - Hans-Joachim Gabius
- Institut für Physiologische Chemie, Tierärztliche Fakultät, Ludwig-Maximilians-Universität, München, Germany; and
| | - Rosa F Hwang
- Department of Surgical Oncology, Division of Surgery, The University of Texas MD Anderson Cancer Center, Houston, Texas
| | - Françoise Poirier
- Institute Jacques Monod, CNRS UMR7592, Université Paris Diderot, Paris, France
| | | | | | - Martin E Fernández-Zapico
- Schulze Center for Novel Therapeutics, Division of Oncology Research, Mayo Clinic, Rochester, Minnesota
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105
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Vislovukh A, Vargas TR, Polesskaya A, Groisman I. Role of 3’-untranslated region translational control in cancer development, diagnostics and treatment. World J Biol Chem 2014; 5:40-57. [PMID: 24600513 PMCID: PMC3942541 DOI: 10.4331/wjbc.v5.i1.40] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/28/2013] [Revised: 11/22/2013] [Accepted: 12/19/2013] [Indexed: 02/05/2023] Open
Abstract
The messenger RNA 3’-untranslated region (3’UTR) plays an important role in regulation of gene expression on the posttranscriptional level. The 3’UTR controls gene expression via orchestrated interaction between the structural components of mRNAs (cis-element) and the specific trans-acting factors (RNA binding proteins and non-coding RNAs). The crosstalk of these factors is based on the binding sequences and/or direct protein-protein interaction, or just functional interaction. Much new evidence that has accumulated supports the idea that several RNA binding factors can bind to common mRNA targets: to the non-overlapping binding sites or to common sites in a competitive fashion. Various factors capable of binding to the same RNA can cooperate or be antagonistic in their actions. The outcome of the collective function of all factors bound to the same mRNA 3’UTR depends on many circumstances, such as their expression levels, affinity to the binding sites, and localization in the cell, which can be controlled by various physiological conditions. Moreover, the functional and/or physical interactions of the factors binding to 3’UTR can change the character of their actions. These interactions vary during the cell cycle and in response to changing physiological conditions. Abnormal functioning of the factors can lead to disease. In this review we will discuss how alterations of these factors or their interaction can affect cancer development and promote or enhance the malignant phenotype of cancer cells. Understanding these alterations and their impact on 3’UTR-directed posttranscriptional gene regulation will uncover promising new targets for therapeutic intervention and diagnostics. We will also discuss emerging new tools in cancer diagnostics and therapy based on 3’UTR binding factors and approaches to improve them.
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106
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Tsai LY, Chang YW, Lin PY, Chou HJ, Liu TJ, Lee PT, Huang WH, Tsou YL, Huang YS. CPEB4 knockout mice exhibit normal hippocampus-related synaptic plasticity and memory. PLoS One 2013; 8:e84978. [PMID: 24386439 PMCID: PMC3875571 DOI: 10.1371/journal.pone.0084978] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2013] [Accepted: 11/27/2013] [Indexed: 11/18/2022] Open
Abstract
Regulated RNA translation is critical to provide proteins needed to maintain persistent modification of synaptic strength, which underlies the molecular basis of long-term memory (LTM). Cytoplasmic polyadenylation element-binding proteins (CPEBs) are sequence-specific RNA-binding proteins and regulate translation in various tissues. All four CPEBs in vertebrates are expressed in the brain, including the hippocampal neurons, suggesting their potential roles in translation-dependent plasticity and memory. Although CPEB1 and CPEB3 have been shown to control specific kinds of hippocampus-related LTM, the role of CPEB2 and CPEB4 in learning and memory remains elusive. Thus, we generated CPEB4 knockout (KO) mice and analyzed them using several behavioral tests. No difference was found in the anxiety level, motor coordination, hippocampus-dependent learning and memory between the KO mice and their wild-type (WT) littermates. Electrophysiological recordings of multiple forms of synaptic plasticity in the Schaffer collateral pathway-CA1 neurons also showed normal responses in the KO hippocampal slices. Morphological analyses revealed that the CPEB4-lacking pyramidal neurons possessed slightly elongated dendritic spines. Unlike its related family members, CPEB1 and CPEB3, CPEB4 seems to be dispensable for hippocampus-dependent plasticity, learning and memory.
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Affiliation(s)
- Li-Yun Tsai
- Institute of Biomedical Sciences, Academia Sinica, Taipei, Taiwan
| | - Yu-Wei Chang
- Institute of Biomedical Sciences, Academia Sinica, Taipei, Taiwan
- Graduate Institute of Life Sciences, National Defense Medical Center, Taipei, Taiwan
| | - Pei-Yi Lin
- Institute of Biomedical Sciences, Academia Sinica, Taipei, Taiwan
| | - Hsin-Jung Chou
- Institute of Biomedical Sciences, Academia Sinica, Taipei, Taiwan
| | - Ta-Jen Liu
- Institute of Biomedical Sciences, Academia Sinica, Taipei, Taiwan
- Institute of Neuroscience, National Yang-Ming University, Taipei, Taiwan
| | - Ping-Tao Lee
- Institute of Biomedical Sciences, Academia Sinica, Taipei, Taiwan
| | - Wen-Hsuan Huang
- Institute of Biomedical Sciences, Academia Sinica, Taipei, Taiwan
| | - Yueh-Liang Tsou
- Institute of Biomedical Sciences, Academia Sinica, Taipei, Taiwan
| | - Yi-Shuian Huang
- Institute of Biomedical Sciences, Academia Sinica, Taipei, Taiwan
- Graduate Institute of Life Sciences, National Defense Medical Center, Taipei, Taiwan
- Institute of Neuroscience, National Yang-Ming University, Taipei, Taiwan
- * E-mail:
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107
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Xu H, Liu B. CPEB4 is a candidate biomarker for defining metastatic cancers and directing personalized therapies. Med Hypotheses 2013; 81:875-7. [DOI: 10.1016/j.mehy.2013.08.030] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2013] [Revised: 07/31/2013] [Accepted: 08/23/2013] [Indexed: 11/17/2022]
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108
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van Vliet-Ostaptchouk JV, den Hoed M, Luan J, Zhao JH, Ong KK, van der Most PJ, Wong A, Hardy R, Kuh D, van der Klauw MM, Bruinenberg M, Khaw KT, Wolffenbuttel BHR, Wareham NJ, Snieder H, Loos RJF. Pleiotropic effects of obesity-susceptibility loci on metabolic traits: a meta-analysis of up to 37,874 individuals. Diabetologia 2013; 56:2134-46. [PMID: 23827965 DOI: 10.1007/s00125-013-2985-y] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/17/2013] [Accepted: 06/12/2013] [Indexed: 12/21/2022]
Abstract
AIMS/HYPOTHESIS Genetic pleiotropy may contribute to the clustering of obesity and metabolic conditions. We assessed whether genetic variants that are robustly associated with BMI and waist-to-hip ratio (WHR) also influence metabolic and cardiovascular traits, independently of obesity-related traits, in meta-analyses of up to 37,874 individuals from six European population-based studies. METHODS We examined associations of 32 BMI and 14 WHR loci, individually and combined in two genetic predisposition scores (GPSs), with glycaemic traits, blood lipids and BP, with and without adjusting for BMI and/or WHR. RESULTS We observed significant associations of BMI-increasing alleles at five BMI loci with lower levels of 2 h glucose (RBJ [also known as DNAJC27], QPTCL: effect sizes -0.068 and -0.107 SD, respectively), HDL-cholesterol (SLC39A8: -0.065 SD, MTCH2: -0.039 SD), and diastolic BP (SLC39A8: -0.069 SD), and higher and lower levels of LDL- and total cholesterol (QPTCL: 0.041 and 0.042 SDs, respectively, FLJ35779 [also known as POC5]: -0.042 and -0.041 SDs, respectively) (all p < 2.4 × 10(-4)), independent of BMI. The WHR-increasing alleles at two WHR loci were significantly associated with higher proinsulin (GRB14: 0.069 SD) and lower fasting glucose levels (CPEB4: -0.049 SD), independent of BMI and WHR. A higher GPS-BMI was associated with lower systolic BP (-0.005 SD), diastolic BP (-0.006 SD) and 2 h glucose (-0.013 SD), while a higher GPS-WHR was associated with lower HDL-cholesterol (-0.015 SD) and higher triacylglycerol levels (0.014 SD) (all p < 2.9 × 10(-3)), independent of BMI and/or WHR. CONCLUSIONS/INTERPRETATION These pleiotropic effects of obesity-susceptibility loci provide novel insights into mechanisms that link obesity with metabolic abnormalities.
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Affiliation(s)
- J V van Vliet-Ostaptchouk
- Department of Endocrinology, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
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109
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Cho KS, Joo SH, Choi CS, Kim KC, Ko HM, Park JH, Kim P, Hur J, Lee SH, Bahn GH, Ryu JH, Lee J, Han SH, Kwon KJ, Shin CY. Glucose deprivation reversibly down-regulates tissue plasminogen activator via proteasomal degradation in rat primary astrocytes. Life Sci 2013; 92:929-37. [DOI: 10.1016/j.lfs.2013.03.011] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2012] [Revised: 03/12/2013] [Accepted: 03/20/2013] [Indexed: 11/30/2022]
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110
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Campbell ZT, Bhimsaria D, Valley CT, Rodriguez-Martinez JA, Menichelli E, Williamson JR, Ansari AZ, Wickens M. Cooperativity in RNA-protein interactions: global analysis of RNA binding specificity. Cell Rep 2013; 1:570-81. [PMID: 22708079 DOI: 10.1016/j.celrep.2012.04.003] [Citation(s) in RCA: 93] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
The control and function of RNA are governed by the specificity of RNA binding proteins. Here, we describe a method for global unbiased analysis of RNA-protein interactions that uses in vitro selection, high-throughput sequencing, and sequence-specificity landscapes. The method yields affinities for a vast array of RNAs in a single experiment, including both low- and high-affinity sites. It is reproducible and accurate. Using this approach,we analyzed members of the PUF (Pumilio and FBF) family of eukaryotic mRNA regulators. Our data identify effects of a specific protein partner on PUF-RNA interactions, reveal subsets of target sites not previously detected, and demonstrate that designer PUF proteins can precisely alter specificity. The approach described here is, in principle, broadly applicable for analysis of any molecule that binds RNA, including proteins, nucleic acids, and small molecules.
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Affiliation(s)
- Zachary T Campbell
- Department of Biochemistry, University of Wisconsin-Madison, 433 Babcock Drive, Madison, WI 53706-1554, USA
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111
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Ciafrè SA, Galardi S. microRNAs and RNA-binding proteins: a complex network of interactions and reciprocal regulations in cancer. RNA Biol 2013; 10:935-42. [PMID: 23696003 PMCID: PMC4111733 DOI: 10.4161/rna.24641] [Citation(s) in RCA: 120] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
In the last decade, an ever-growing number of connections between microRNAs (miRNAs) and RNA-binding proteins (RBPs) have uncovered a new level of complexity of gene expression regulation in cancer. In this review, we examine several aspects of the functional interactions between miRNAs and RBPs in cancer models. We will provide examples of reciprocal regulation: miRNAs regulating the expression of RBPs, or the converse, where an RNA-binding protein specifically regulates the expression of a specific miRNA, or when an RBP can exert a widespread effect on miRNAs via the modulation of a key protein for miRNA production or function. Moreover, we will focus on the ever-growing number of functional interactions that have been discovered in the last few years: RBPs that were shown to cooperate with microRNAs in the downregulation of shared target mRNAs or, on the contrary, that inhibit microRNA action, thus resulting in a protection of the specific target mRNAs. We surely need to obtain a deeper comprehension of such intricate networks to have a chance of understanding and, thus, fighting cancer.
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Affiliation(s)
- Silvia Anna Ciafrè
- Department of Biomedicine and Prevention, University of Rome Tor Vergata, Via Montpellier, Roma, Italy.
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112
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D'Ambrogio A, Nagaoka K, Richter JD. Translational control of cell growth and malignancy by the CPEBs. Nat Rev Cancer 2013; 13:283-90. [PMID: 23446545 DOI: 10.1038/nrc3485] [Citation(s) in RCA: 88] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
The cytoplasmic polyadenylation element binding proteins (CPEBs) associate with specific sequences in mRNA 3' untranslated regions to promote translation. They do so by inducing cytoplasmic polyadenylation, which requires specialized poly(A) polymerases. Aberrant expression of these proteins correlates with certain types of cancer, indicating that cytoplasmic RNA 3' end processing is important in the control of growth. Several CPEB-regulated mRNAs govern cell cycle progression, regulate senescence, establish cell polarity, and promote tumorigenesis and metastasis. In this Opinion article, we discuss the emerging evidence that indicates a key role for the CPEBs in cancer biology.
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Affiliation(s)
- Andrea D'Ambrogio
- The Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, Massachusetts 01605, USA
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113
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Ruggero D. Translational control in cancer etiology. Cold Spring Harb Perspect Biol 2013; 5:cshperspect.a012336. [PMID: 22767671 DOI: 10.1101/cshperspect.a012336] [Citation(s) in RCA: 221] [Impact Index Per Article: 20.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The link between perturbations in translational control and cancer etiology is becoming a primary focus in cancer research. It has now been established that genetic alterations in several components of the translational apparatus underlie spontaneous cancers as well as an entire class of inherited syndromes known as "ribosomopathies" associated with increased cancer susceptibility. These discoveries have illuminated the importance of deregulations in translational control to very specific cellular processes that contribute to cancer etiology. In addition, a growing body of evidence supports the view that deregulation of translational control is a common mechanism by which diverse oncogenic pathways promote cellular transformation and tumor development. Indeed, activation of these key oncogenic pathways induces rapid and dramatic translational reprogramming both by increasing overall protein synthesis and by modulating specific mRNA networks. These translational changes promote cellular transformation, impacting almost every phase of tumor development. This paradigm represents a new frontier in the multihit model of cancer formation and offers significant promise for innovative cancer therapies. Current research, in conjunction with cutting edge technologies, will further enable us to explore novel mechanisms of translational control, functionally identify translationally controlled mRNA groups, and unravel their impact on cellular transformation and tumorigenesis.
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Affiliation(s)
- Davide Ruggero
- Helen Diller Cancer Center, School of Medicine, University of California, San Francisco, CA 94158, USA.
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114
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Abstract
Cytoplasmic polyadenylation element-binding protein 1 (CPEB1) is an mRNA-binding protein present in both neurons and glia. CPEB1 is capable of both repressing mRNA translation and activating it depending upon its phosphorylation state. CPEB1-bound mRNAs are held in translational dormancy until CPEB1 is phosphorylated, leading to the cytoplasmic polyadenylation of the bound mRNA that triggers translation. Here, we show that CPEB1 can bind to and regulate translation of the mRNA-encoding metadherin (MTDH, also known as AEG-1 and Lyric) in the rat glioblastoma cell line CNS1. MTDH/AEG-1 is being revealed as a critical signaling molecule in tumor progression, playing roles in invasion, metastasis, and chemoresistance. By using a mutant of CPEB1 that cannot be phosphorylated (thereby holding target mRNAs in translational arrest), we show that inhibiting CPEB1-mediated translation blocks MTDH/AEG-1 expression in vitro and inhibits glioblastomas tumor growth in vivo. CPEB1-mediated translation is likely to impact several signaling pathways that may promote tumor progression, but we present evidence suggesting a role in directed cell migration in glioblastoma cells. In addition, reporter mRNA containing CPEB1-binding sites is transported to the leading edge of migrating cells and translated, whereas the same mRNA with point mutations in the binding sites is synthesized perinuclearly. Our findings show that CPEB1 is hyperactive in rat glioblastoma cells and is regulating an important cohort of mRNAs whose increased translation is fueling the progression of tumor proliferation and dispersal in the brain. Thus, targeting CPEB1-mediated mRNA translation might be a sound therapeutic approach.
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Affiliation(s)
- Dawn M Kochanek
- Department of Molecular, Cellular & Developmental Biology, 260 Whitney Ave, KBT 338, Box 208103, New Haven, CT 06520, USA
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115
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Tian Q, Liang L, Ding J, Zha R, Shi H, Wang Q, Huang S, Guo W, Ge C, Chen T, Li J, He X. MicroRNA-550a acts as a pro-metastatic gene and directly targets cytoplasmic polyadenylation element-binding protein 4 in hepatocellular carcinoma. PLoS One 2012; 7:e48958. [PMID: 23145039 PMCID: PMC3492136 DOI: 10.1371/journal.pone.0048958] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2012] [Accepted: 10/02/2012] [Indexed: 12/22/2022] Open
Abstract
MicroRNAs (miRNAs) are a class of small, non-coding RNA molecules that are often found at chromosomal breakpoints and play a vital role in human cancer. Our previous study found that miR-550a, a frequently amplified miRNA on 7p14.3, was upregulated in hepatocellular carcinoma (HCC). However, the possible functions and molecular mechanisms of miR-550a in HCC remain unknown. In this study, gain-of-function and loss-of-function assays revealed that miR-550a markedly promoted HCC cell migration and invasion. In addition, we discovered that cytoplasmic polyadenylation element binding protein 4 (CPEB4) was a potential target of miR-550a in HCC. Further analyses showed that knockdown of CPEB4 expression significantly facilitated HCC cell migration and invasion, which phenocopied the effects of miR-550a on HCC cells. Moreover, a decrease in CPEB4 expression mediated miR-550a-induced liver cancer cell migration and invasion. Interestingly, CPEB4 is frequently downregulated in HCC, and its expression levels correlate with the overall survival of HCC patients. Together, these results suggested that this newly identified miR-550a-CPEB4 axis may be involved in HCC cell metastasis. Moreover, the expression levels of CPEB4 could be used to predict outcomes in HCC patients. Our findings provide novel potential targets for HCC therapy and prognosis.
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Affiliation(s)
- Qi Tian
- State Key Laboratory of Oncogenes and Related Genes, Shanghai Cancer Institute, Renji Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Linhui Liang
- State Key Laboratory of Oncogenes and Related Genes, Shanghai Cancer Institute, Renji Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Jie Ding
- State Key Laboratory of Oncogenes and Related Genes, Shanghai Cancer Institute, Renji Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Ruopeng Zha
- State Key Laboratory of Oncogenes and Related Genes, Shanghai Cancer Institute, Renji Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Haibing Shi
- State Key Laboratory of Oncogenes and Related Genes, Shanghai Cancer Institute, Renji Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Qifeng Wang
- State Key Laboratory of Oncogenes and Related Genes, Shanghai Cancer Institute, Renji Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Shenglin Huang
- State Key Laboratory of Oncogenes and Related Genes, Shanghai Cancer Institute, Renji Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Weijie Guo
- State Key Laboratory of Oncogenes and Related Genes, Shanghai Cancer Institute, Renji Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Chao Ge
- State Key Laboratory of Oncogenes and Related Genes, Shanghai Cancer Institute, Renji Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Taoyang Chen
- Qi Dong Liver Cancer Institute, Qi Dong, Jiangsu, China
| | - Jinjun Li
- State Key Laboratory of Oncogenes and Related Genes, Shanghai Cancer Institute, Renji Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Xianghuo He
- State Key Laboratory of Oncogenes and Related Genes, Shanghai Cancer Institute, Renji Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
- * E-mail:
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116
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Fernández-Miranda G, Méndez R. The CPEB-family of proteins, translational control in senescence and cancer. Ageing Res Rev 2012; 11:460-72. [PMID: 22542725 DOI: 10.1016/j.arr.2012.03.004] [Citation(s) in RCA: 115] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2012] [Revised: 03/14/2012] [Accepted: 03/27/2012] [Indexed: 12/31/2022]
Abstract
Cytoplasmic elongation of the poly(A) tail was originally identified as a mechanism to activate maternal mRNAs, stored as silent transcripts with short poly(A) tails, during meiotic progression. A family of RNA-binding proteins named CPEBs, which recruit the translational repression or cytoplasmic polyadenylation machineries to their target mRNAs, directly mediates cytoplasmic polyadenylation. Recent years have witnessed an explosion of studies showing that CPEBs are not only expressed in a variety of somatic tissues, but have essential functions controlling gene expression in time and space in the adult organism. These "new" functions of the CPEBs include regulating the balance between senescence and proliferation and its pathological manifestation, tumor development. In this review, we summarize current knowledge on the functions of the CPEB-family of proteins in the regulation of cell proliferation, their target mRNAs and the mechanism controlling their activities.
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117
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Floor SL, Dumont JE, Maenhaut C, Raspe E. Hallmarks of cancer: of all cancer cells, all the time? Trends Mol Med 2012; 18:509-15. [PMID: 22795735 DOI: 10.1016/j.molmed.2012.06.005] [Citation(s) in RCA: 79] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2012] [Revised: 06/15/2012] [Accepted: 06/15/2012] [Indexed: 01/17/2023]
Abstract
In two landmark articles, Hanahan and Weinberg synthesized into one conceptual framework 'the hallmarks of cancer', a massive amount of information describing the characteristics of a cancer cell. Although this is neither the intention nor the belief of the authors, hallmarks are often interpreted as applying to a canonic cancer cell, or equally to all cells within a cancer. In this article, we clarify the separate concepts of causes, oncogenic events, signal transduction programs, and hallmarks to show that there is no unimodal relation between these concepts but a complex network of interrelations that vary in different cells, between cells, and at different times in any given cell. We consider cancer as an evolving, dynamic, and heterogeneous system, explaining, at least in part, the difficulty of treating cancer and supporting the use of simultaneous, multitarget therapies.
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Affiliation(s)
- Sébastien L Floor
- Institute for Interdisciplinary Research in Human Molecular Biology (IRIBHM), Université Libre de Bruxelles, B-1070 Brussels, Belgium
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118
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Weill L, Belloc E, Bava FA, Méndez R. Translational control by changes in poly(A) tail length: recycling mRNAs. Nat Struct Mol Biol 2012; 19:577-85. [PMID: 22664985 DOI: 10.1038/nsmb.2311] [Citation(s) in RCA: 233] [Impact Index Per Article: 19.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Beyond the well-known function of poly(A) tail length in mRNA stability, recent years have witnessed an explosion of information about how changes in tail length and the selection of alternative polyadenylation sites contribute to the translational regulation of a large portion of the genome. The mechanisms and factors mediating nuclear and cytoplasmic changes in poly(A) tail length have been studied in great detail, the targets of these mechanisms have been identified--in some cases by genome-wide screenings--and changes in poly(A) tail length are now implicated in a number of physiological and pathological processes. However, in very few cases have all three levels--mechanisms, targets and functions--been studied together.
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Affiliation(s)
- Laure Weill
- Institute for Research in Biomedicine-IRB Barcelona, Barcelona, Spain
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119
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Versatility of RNA-Binding Proteins in Cancer. Comp Funct Genomics 2012; 2012:178525. [PMID: 22666083 PMCID: PMC3359819 DOI: 10.1155/2012/178525] [Citation(s) in RCA: 81] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2011] [Accepted: 02/28/2012] [Indexed: 01/22/2023] Open
Abstract
Posttranscriptional gene regulation is a rapid and efficient process to adjust the proteome of a cell to a changing environment. RNA-binding proteins (RBPs) are the master regulators of mRNA processing and translation and are often aberrantly expressed in cancer. In addition to well-studied transcription factors, RBPs are emerging as fundamental players in tumor development. RBPs and their mRNA targets form a complex network that plays a crucial role in tumorigenesis. This paper describes mechanisms by which RBPs influence the expression of well-known oncogenes, focusing on precise examples that illustrate the versatility of RBPs in posttranscriptional control of cancer development. RBPs appeared very early in evolution, and new RNA-binding domains and combinations of them were generated in more complex organisms. The identification of RBPs, their mRNA targets, and their mechanism of action have provided novel potential targets for cancer therapy.
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120
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Campbell ZT, Menichelli E, Friend K, Wu J, Kimble J, Williamson JR, Wickens M. Identification of a conserved interface between PUF and CPEB proteins. J Biol Chem 2012; 287:18854-62. [PMID: 22496444 DOI: 10.1074/jbc.m112.352815] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Members of the PUF (Pumilio and FBF) and CPEB (cytoplasmic polyadenylation element-binding) protein families collaborate to regulate mRNA expression throughout eukaryotes. Here, we focus on the physical interactions between members of these two families, concentrating on Caenorhabditis elegans FBF-2 and CPB-1. To localize the site of interaction on FBF-2, we identified conserved amino acids within C. elegans PUF proteins. Deletion of an extended loop containing several conserved residues abolished binding to CPB-1. We analyzed alanine substitutions at 13 individual amino acids in FBF-2, each identified via its conservation. Multiple single point mutations disrupted binding to CPB-1 but not to RNA. Position Tyr-479 was particularly critical as multiple substitutions to other amino acids at this position did not restore binding. The complex of FBF-2 and CPB-1 repressed translation of an mRNA containing an FBF binding element. Repression required both proteins and was disrupted by FBF-2 alleles that failed to bind CPB-1 or RNA. The equivalent loop in human PUM2 is required for binding to human CPEB3 in vitro, although the primary sequences of the human and C. elegans PUF proteins have diverged in that region. Our findings define a key region in PUF/CPEB interactions and imply a conserved platform through which PUF proteins interact with their protein partners.
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Affiliation(s)
- Zachary T Campbell
- Department of Biochemistry, University of Wisconsin, Madison, Wisconsin 53706, USA
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