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Wang PF, Wang X, Liu M, Zeng Z, Lin C, Xu W, Ma W, Wang J, Xiang Q, Johnston RN, Liu H, Liu SL. The Oncogenic Functions of Insulin-like Growth Factor 2 mRNA-Binding Protein 3 in Human Carcinomas. Curr Pharm Des 2020; 26:3939-3954. [PMID: 32282295 DOI: 10.2174/1381612826666200413080936] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2019] [Accepted: 04/01/2020] [Indexed: 02/07/2023]
Abstract
IGF2BP3 (also known as IMP3, KOC), a member of the insulin-like growth factor mRNA-binding protein family (IMPs), has been a research target in recent studies of promoting embryo development and exacerbating cancer. IGF2BP3 is ubiquitously expressed in early embryogenesis stages but limited in postembryonic stages, which is important in many physiological aspects such as stem cell renewal, morphological development and metabolism. A large number of studies show that IGF2BP3 interacts with many kinds of non-coding RNAs and proteins to promote cancer cell proliferation and metastasis and inhibit cancer cell apoptosis. As IGF2BP3 is highly expressed in advanced cancers and associated with poor overall survival rates of patients, it may be a potential molecular marker in cancer diagnosis for the detection of cancerous tissues and an indicator of cancer stages. Therefore, anti-IGF2BP3 drugs or monoclonal antibodies are expected as new therapeutic methods in cancer treatment. This review summarizes recent findings among IGF2BP3, RNA and proteins in cancer processes, with a focus on its cancer-promoting mechanisms and potential application as a new biomarker for cancer diagnosis and treatment.
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Affiliation(s)
- Peng-Fei Wang
- Genomics Research Center (State-Province Key Laboratories of Biomedicine-Pharmaceutics of China), College of Pharmacy, Harbin Medical University, Harbin, 150081, China
| | - Xiaoyu Wang
- Genomics Research Center (State-Province Key Laboratories of Biomedicine-Pharmaceutics of China), College of Pharmacy, Harbin Medical University, Harbin, 150081, China
| | - Min Liu
- Genomics Research Center (State-Province Key Laboratories of Biomedicine-Pharmaceutics of China), College of Pharmacy, Harbin Medical University, Harbin, 150081, China
| | - Zheng Zeng
- Genomics Research Center (State-Province Key Laboratories of Biomedicine-Pharmaceutics of China), College of Pharmacy, Harbin Medical University, Harbin, 150081, China
| | - Caiji Lin
- Genomics Research Center (State-Province Key Laboratories of Biomedicine-Pharmaceutics of China), College of Pharmacy, Harbin Medical University, Harbin, 150081, China
| | - Wenwen Xu
- Genomics Research Center (State-Province Key Laboratories of Biomedicine-Pharmaceutics of China), College of Pharmacy, Harbin Medical University, Harbin, 150081, China
| | - Wenqing Ma
- Genomics Research Center (State-Province Key Laboratories of Biomedicine-Pharmaceutics of China), College of Pharmacy, Harbin Medical University, Harbin, 150081, China
| | - Jiali Wang
- Genomics Research Center (State-Province Key Laboratories of Biomedicine-Pharmaceutics of China), College of Pharmacy, Harbin Medical University, Harbin, 150081, China
| | - Qian Xiang
- Genomics Research Center (State-Province Key Laboratories of Biomedicine-Pharmaceutics of China), College of Pharmacy, Harbin Medical University, Harbin, 150081, China
| | - Randal N Johnston
- Department of Biochemistry and Molecular Biology, University of Calgary, Calgary, T2N1N4, Canada
| | - Huidi Liu
- Genomics Research Center (State-Province Key Laboratories of Biomedicine-Pharmaceutics of China), College of Pharmacy, Harbin Medical University, Harbin, 150081, China
| | - Shu-Lin Liu
- Genomics Research Center (State-Province Key Laboratories of Biomedicine-Pharmaceutics of China), College of Pharmacy, Harbin Medical University, Harbin, 150081, China
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Pickard A, Durzynska J, McCance DJ, Barton ER. The IGF axis in HPV associated cancers. MUTATION RESEARCH-REVIEWS IN MUTATION RESEARCH 2017; 772:67-77. [PMID: 28528691 DOI: 10.1016/j.mrrev.2017.01.002] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/26/2016] [Revised: 01/30/2017] [Accepted: 01/30/2017] [Indexed: 02/07/2023]
Abstract
Human papillomaviruses (HPV) infect and replicate in stratified epithelium at cutaneous and mucosal surfaces. The proliferation and maintenance of keratinocytes, the cells which make up this epithelium, are controlled by a number of growth factor receptors such as the keratinocyte growth factor receptor (KGFR, also called fibroblast growth factor receptor 2b (FGFR2b)), the epithelial growth factor receptor (EGFR) and the insulin-like growth factor receptors 1 and 2 (IGF1R and IGF2R). In this review, we will delineate the mutation, gene transcription, translation and processing of the IGF axis within HPV associated cancers. The IGFs are key for developmental and postnatal growth of almost all tissues; we explore whether this crucial axis has been hijacked by HPV.
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MESH Headings
- Cell Proliferation
- ErbB Receptors/genetics
- ErbB Receptors/metabolism
- Gene Expression Regulation, Neoplastic
- Humans
- Keratinocytes/cytology
- Keratinocytes/virology
- Neoplasms/genetics
- Neoplasms/virology
- Papillomaviridae/pathogenicity
- Receptor, Fibroblast Growth Factor, Type 2/genetics
- Receptor, Fibroblast Growth Factor, Type 2/metabolism
- Receptor, IGF Type 1
- Receptor, IGF Type 2/genetics
- Receptor, IGF Type 2/metabolism
- Receptors, Somatomedin/genetics
- Receptors, Somatomedin/metabolism
- Somatomedins/genetics
- Somatomedins/metabolism
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Affiliation(s)
- Adam Pickard
- Centre for Cancer Research and Cell Biology, Queen's University Belfast, Belfast, BT9 7AE, UK; Wellcome Centre for Cell Matrix Research, University of Manchester, M13 9PL, UK.
| | - Julia Durzynska
- Department of Molecular Virology, Institute of Experimental Biology, A. Mickiewicz University, ul. Umultowska 89, 61-614, Poznań, Poland; Department of Applied Physiology and Kinesiology, College of Health and Human Performance, University of Florida, Gainesville, FL, USA
| | - Dennis J McCance
- Department of Pathology, University of New Mexico, Albuquerque, NM, USA
| | - Elisabeth R Barton
- Department of Applied Physiology and Kinesiology, College of Health and Human Performance, University of Florida, Gainesville, FL, USA
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Dynkevich Y, Rother KI, Whitford I, Qureshi S, Galiveeti S, Szulc AL, Danoff A, Breen TL, Kaviani N, Shanik MH, Leroith D, Vigneri R, Koch CA, Roth J. Tumors, IGF-2, and hypoglycemia: insights from the clinic, the laboratory, and the historical archive. Endocr Rev 2013; 34:798-826. [PMID: 23671155 DOI: 10.1210/er.2012-1033] [Citation(s) in RCA: 143] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Tumors of mesenchymal and epithelial origin produce IGF-2, which activates pathways in the tumors. In a minority of patients, the tumors (hepatomas, fibromas, and fibrosarcomas are the most common among many) release into the circulation enough IGF-2-related peptides to mimic the fasting hypoglycemia characteristic of patients with insulin-producing islet-cell tumors. Rarely, markedly elevated IGF-2 levels produce somatic changes suggestive of acromegaly. Typically, the elevated IGF-2 levels are associated with suppressed plasma levels of insulin, IGF-1, and GH. Complicating the pathophysiology are the IGF binding proteins (IGFBPs) that can bind IGF-2 and IGF-1, modifying hormone metabolism and action. IGFBP concentrations are often altered in the presence of these tumors. At the cellular level, the 3 hormone-related ligands, IGF-2, IGF-1, and insulin, all bind to 4 (or more) types of IGF-1 receptor (IGF-1R) and insulin receptor (IR). Each receptor has its own characteristic affinity for each ligand, a tyrosine kinase, and overlapping profiles of action in the target cells. The IGF-2R, in addition to binding mannose-6-phosphate-containing proteins, provides an IGF-2 degradation pathway. Recent evidence suggests IGF-2R involvement also in signal transduction. Surgery, the treatment of choice, can produce a cure. For patients not cured by surgery, multiple therapies exist, for the tumor and for hypoglycemia. Potential future therapeutic approaches are sketched. From 1910 to 1930, hypoglycemia, insulin, insulinomas, and non-islet-cell tumors were recognized. The latter third of the century witnessed the emergence of the immunoassay for insulin; the IGFs, their binding proteins, and assays to measure them; and receptors for the insulin-related peptides as well as the intracellular pathways beyond the receptor. In closing, we replace non-islet-cell tumor hypoglycemia, an outdated and misleading label, with IGF-2-oma, self-explanatory and consistent with names of other hormone-secreting tumors.
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Affiliation(s)
- Yevgeniya Dynkevich
- MD, FACP, Investigator, Feinstein Institute for Medical Research, Laboratory of Diabetes and Diabetes-Related Research, 350 Community Drive, Manhasset, NY 11030.
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Liao B, Hu Y, Brewer G. RNA-binding protein insulin-like growth factor mRNA-binding protein 3 (IMP-3) promotes cell survival via insulin-like growth factor II signaling after ionizing radiation. J Biol Chem 2011; 286:31145-52. [PMID: 21757716 DOI: 10.1074/jbc.m111.263913] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Ionizing radiation (IR) induces proapoptotic gene expression programs that inhibit cell survival. These programs often involve RNA-binding proteins that associate with their mRNA targets to elicit changes in mRNA stability and/or translation. The RNA-binding protein IMP-3 is an oncofetal protein overexpressed in many human malignancies. IMP-3 abundance correlates with tumor aggressiveness and poor prognosis. As such, IMP-3 is proving to be a highly significant biomarker in surgical pathology. Among its many mRNA targets, IMP-3 binds to and promotes translation of insulin-like growth factor II (IGFII) mRNA. Our earlier studies showed that reducing IMP-3 abundance with siRNAs reduced proliferation of human K562 chronic myeloid leukemia cells because of reduced IGF-II biosynthesis. However, the role of IMP-3 in apoptosis is unknown. Here, we have used IR-induced apoptosis of K562 cells as a model to explore a role for IMP-3 in cell survival. Knockdown of IMP-3 with siRNA increased susceptibility of cells to IR-induced apoptosis and led to reduced IGF-II production. Gene reporter assays revealed that IMP-3 acts through the 5' UTR of IGFII mRNA during apoptosis to promote translation. Finally, culture of IR-treated cells with recombinant IGF-II partially reversed the effects of IMP-3 knockdown on IR-induced apoptosis. Together, these results indicate that IMP-3 acts in part through the IGF-II pathway to promote cell survival in response to IR. Thus, IMP-3 might serve as a new drug target to increase sensitivity of CML cells or other cancers to IR therapy.
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Affiliation(s)
- Baisong Liao
- Department of Molecular Genetics, Microbiology, and Immunology, University of Medicine and Dentistry of New Jersey, Robert Wood Johnson Medical School, Piscataway, New Jersey 08854, USA
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Leautaud V, Demple B. Regulation of heme oxygenase-1 mRNA deadenylation and turnover in NIH3T3 cells by nitrosative or alkylation stress. BMC Mol Biol 2007; 8:116. [PMID: 18096048 PMCID: PMC2246143 DOI: 10.1186/1471-2199-8-116] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2007] [Accepted: 12/20/2007] [Indexed: 11/22/2022] Open
Abstract
Background Heme oxygenase-1 (HO-1) catalizes heme degradation, and is considered one of the most sensitive indicators of cellular stress. Previous work in human fibroblasts has shown that HO-1 expression is induced by NO, and that transcriptional induction is only partially responsible; instead, the HO-1 mRNA half-life is substantially increased in response to NO. The mechanism of this stabilization remains unknown. Results In NIH3T3 murine fibroblasts, NO exposure increased the half-life of the HO-1 transcript from ~1.6 h to 11 h, while treatments with CdCl2, NaAsO2 or H2O2 increased the half-life only up to 5 h. Although poly(A) tail shortening can be rate-limiting in mRNA degradation, the HO-1 mRNA deadenylation rate in NO-treated cells was ~65% of that in untreated controls. In untreated cells, HO-1 poly(A) removal proceeded until 30–50 nt remained, followed by rapid mRNA decay. In NO-treated cells, HO-1 deadenylation stopped with the mRNA retaining poly(A) tails 30–50 nt long. We hypothesize that NO treatment stops poly(A) tail shortening at the critical 30- to 50-nt length. This is not a general mechanism for the post-transcriptional regulation of HO-1 mRNA. Methyl methane sulfonate also stabilized HO-1 mRNA, but that was associated with an 8-fold decrease in the deadenylation rate compared to that of untreated cells. Another HO-1 inducer, CdCl2, caused a strong increase in the mRNA level without affecting the HO-1 mRNA half-life. Conclusion The regulation of HO-1 mRNA levels in response to cellular stress can be induced by transcriptional and different post-transcriptional events that act independently, and vary depending on the stress inducer. While NO appears to stabilize HO-1 mRNA by preventing the final steps of deadenylation, methyl methane sulfonate achieves stabilization through the regulation of earlier stages of deadenylation.
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Affiliation(s)
- Veronica Leautaud
- Department of Genetics and Complex Diseases, Harvard School of Public Health, 665 Huntington Avenue, Boston, MA 02115, USA.
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Abstract
Insulin-like growth factor 2 (IGF2) is an imprinted gene expressed in most tissues affecting lean muscle content in mice, pigs and cattle. We previously identified the bovine IGF2 c.-292C>T SNP in the non-translated exon 2. Using this SNP, we demonstrated biallelic expression of IGF2 after birth. Seven alternatively spliced mRNA transcripts of IGF2 were expressed among 15 tissues. An IGF2 pseudogene (psiIGF2) was identified with sequence identical to at least IGF2 exons 2 and 3 without the intervening intron. The biallelic expression of this c.-292C>T SNP was associated with an increase in rib eye area (REA) in two populations of cattle, with the C.-292C allele associated with a 10% increase. A significant association with per cent fat was found in one of the populations.
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Affiliation(s)
- J J Goodall
- Department of Animal and Poultry Science, University of Saskatchewan, Saskatoon, SK S7N 5A8, Canada.
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Finoux AL, Séraphin B. In Vivo Targeting of the Yeast Pop2 Deadenylase Subunit to Reporter Transcripts Induces Their Rapid Degradation and Generates New Decay Intermediates. J Biol Chem 2006; 281:25940-7. [PMID: 16793769 DOI: 10.1074/jbc.m600132200] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Deadenylation is the rate-limiting step of mRNA decay, yet little is known about the mechanism regulating this process. In yeast, deadenylation is mainly mediated by the Pop2-Ccr4 complex. We tested whether the selective recruitment of this deadenylase to target mRNAs was sufficient to stimulate their decay in vivo. For this purpose, the Pop2 factor was fused to a U1A RNA binding domain while U1A binding sites were inserted in untranslated regions of a reporter transcript. Analysis of the reporter fate in strains expressing the Pop2-U1A-RBD fusion demonstrated a specific activation of target mRNA decay. Increased mRNA degradation involved accumulation of deadenylated mRNAs that was not detected when the control factors Dcp2 or Pub1 were tethered to the same transcript. The rapid target mRNA degradation was also accompanied by the appearance of new decay intermediates generated by the 3' -5' trimming of the corresponding 3' -untranslated region. Interestingly, this process was not mediated by the exosome but may result from the activity of the Pop2-Ccr4 deadenylase itself. These results indicate that selective recruitment of the Pop2-Ccr4 deadenylase is sufficient to activate mRNA decay, even though this process can also be stimulated by additional mechanisms. Furthermore, deadenylase recruitment affects the downstream path of mRNA decay.
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Affiliation(s)
- Anne-Laure Finoux
- Equipe Labelisée La Ligue, Centre de Génétique Moléculaire, CNRS Unite Propre de Recherche 2167 Associée à l'Université P. et M. Curie, Avenue de la Terrasse, 91198 Gif sur Yvette Cedex, France
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Zekri L, Chebli K, Tourrière H, Nielsen FC, Hansen TVO, Rami A, Tazi J. Control of fetal growth and neonatal survival by the RasGAP-associated endoribonuclease G3BP. Mol Cell Biol 2005; 25:8703-16. [PMID: 16166649 PMCID: PMC1265751 DOI: 10.1128/mcb.25.19.8703-8716.2005] [Citation(s) in RCA: 65] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The regulation of mRNA stability plays a major role in the control of gene expression during cell proliferation, differentiation, and development. Here, we show that inactivation of the RasGAP-associated endoribonuclease (G3BP)-encoding gene leads to embryonic lethality and growth retardation. G3BP-/- mice that survived to term exhibited increased apoptotic cell death in the central nervous system and neonatal lethality. Both in mouse embryonic fibroblasts and during development, the absence of G3BP altered the expression of essential growth factors, among which imprinted gene products and growth arrest-specific mRNAs were outstanding. The results demonstrate that G3BP is essential for proper embryonic growth and development by mediating the coordinate expression of multiple imprinted growth-regulatory transcripts.
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Affiliation(s)
- Latifa Zekri
- Institut de Génétique Moléculaire de Montpellier UMR 5535, IFR 122, Centre National de Recherche Scientifique, 1919 route de Mende, 34293 Montpellier, France
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Meyer S, Temme C, Wahle E. Messenger RNA turnover in eukaryotes: pathways and enzymes. Crit Rev Biochem Mol Biol 2005; 39:197-216. [PMID: 15596551 DOI: 10.1080/10409230490513991] [Citation(s) in RCA: 243] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
The control of mRNA degradation is an important component of the regulation of gene expression since the steady-state concentration of mRNA is determined both by the rates of synthesis and of decay. Two general pathways of mRNA decay have been described in eukaryotes. Both pathways share the exonucleolytic removal of the poly(A) tail (deadenylation) as the first step. In one pathway, deadenylation is followed by the hydrolysis of the cap and processive degradation of the mRNA body by a 5' exonuclease. In the second pathway, the mRNA body is degraded by a complex of 3' exonucleases before the remaining cap structure is hydrolyzed. This review discusses the proteins involved in the catalysis and control of both decay pathways.
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Affiliation(s)
- Sylke Meyer
- Institut für Biochemie, Martin-Luther-Universität Halle-Wittenberg, Halle, Germany
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Liao B, Patel M, Hu Y, Charles S, Herrick DJ, Brewer G. Targeted Knockdown of the RNA-binding Protein CRD-BP Promotes Cell Proliferation via an Insulin-like Growth Factor II-dependent Pathway in Human K562 Leukemia Cells. J Biol Chem 2004; 279:48716-24. [PMID: 15355996 DOI: 10.1074/jbc.m405853200] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The c-myc mRNA coding region determinant-binding protein (CRD-BP) was first identified as a masking protein that stabilizes c-myc mRNA in a cell-free mRNA degradation system. Thus, CRD-BP is thought to promote cell proliferation by maintaining c-Myc at critical levels. CRD-BP also appears to be an oncofetal protein, based upon its expression during mammalian development and in some tumors. By using K562 leukemia cells as a model, we show that CRD-BP gene silencing by RNA interference significantly promoted proliferation, indicating an inhibitory effect of CRD-BP on proliferation. Unexpectedly, CRD-BP knockdown had no discernible effect on c-myc mRNA levels. CRD-BP is also known as insulin-like growth factor II (IGF-II) mRNA-binding protein-1. It has been reported to repress translation of a luciferase reporter mRNA containing an IGF-II 5'-untranslated region known as leader 3 but not one containing IGF-II leader 4. CRD-BP knockdown markedly increased IGF-II mRNA and protein levels but did not alter translation of luciferase reporter mRNAs containing 5'-untranslated regions consisting of either IGF-II leader 3 or leader 4. Addition of antibody against IGF-II to cell cultures inhibited the proliferative effect of CRD-BP knockdown, suggesting that regulation of IGF-II gene expression, rather than c-myc mRNA levels, mediates the proliferative effect of CRD-BP knockdown. Thus, we have identified a dominant function for CRD-BP in cell proliferation of human K562 cells, involving a possible IGF-II-dependent mechanism that appears independent of its ability to serve as a c-myc mRNA masking protein.
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Affiliation(s)
- Baisong Liao
- Department of Molecular Genetics, Microbiology, and Immunology, Robert Wood Johnson Medical School, University of Medicine and Dentistry of New Jersey, Piscataway, New Jersey 08854, USA
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Abstract
Eukaryotic mRNAs are primarily degraded by removal of the 3' poly(A) tail, followed either by cleavage of the 5' cap structure (decapping) and 5'->3' exonucleolytic digestion, or by 3' to 5' degradation. mRNA decapping represents a critical step in turnover because this permits the degradation of the mRNA and is a site of numerous control inputs. Recent analyses suggest decapping of an mRNA consists of four central and related events. These include removal, or inactivation, of the poly(A) tail as an inhibitor of decapping, exit from active translation, assembly of a decapping complex on the mRNA, and sequestration of the mRNA into discrete cytoplasmic foci where decapping can occur. Each of these steps is a demonstrated, or potential, site for the regulation of mRNA decay. We discuss the decapping process in the light of these central properties, which also suggest fundamental aspects of cytoplasmic mRNA physiology that connect decapping, translation, and storage of mRNA.
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Affiliation(s)
- Jeff Coller
- Howard Hughes Medical Institute, Department of Molecular and Cellular Biology, University of Arizona, Tucson, Arizona 85721, USA.
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Abstract
Understanding gene expression control requires defining the molecular and cellular basis of mRNA turnover. We have previously shown that the human decapping factors hDcp2 and hDcp1a are concentrated in specific cytoplasmic structures. Here, we show that hCcr4, hDcp1b, hLsm, and rck/p54 proteins related to 5'-3' mRNA decay also localize to these structures, whereas DcpS, which is involved in cap nucleotide catabolism, is nuclear. Functional analysis using fluorescence resonance energy transfer revealed that hDcp1a and hDcp2 interact in vivo in these structures that were shown to differ from the previously described stress granules. Our data indicate that these new structures are dynamic, as they disappear when mRNA breakdown is abolished by treatment with inhibitors. Accumulation of poly(A)(+) RNA in these structures, after RNAi-mediated inactivation of the Xrn1 exonuclease, demonstrates that they represent active mRNA decay sites. The occurrence of 5'-3' mRNA decay in specific subcellular locations in human cells suggests that the cytoplasm of eukaryotic cells may be more organized than previously anticipated.
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Affiliation(s)
- Nicolas Cougot
- Equipe labellisée La Ligue, Centre de Génétique Moléculaire, Centre National de la Recherche Scientifique, Avenue de la Terrasse, 91198 Gif sur Yvette, France
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Kim EJ, Holthuizen PE, Park HS, Ha YL, Jung KC, Park JHY. Trans-10,cis-12-conjugated linoleic acid inhibits Caco-2 colon cancer cell growth. Am J Physiol Gastrointest Liver Physiol 2002; 283:G357-67. [PMID: 12121883 DOI: 10.1152/ajpgi.00495.2001] [Citation(s) in RCA: 76] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
A commercially available mixture of conjugated linoleic acid (CLA) isomers decreases colon cancer cell growth. We compared the individual potencies of the two main isomers in this mixture [cis-9,trans-11 (c9t11) and trans-10,cis-12 (t10c12)] and assessed whether decreased cell growth is related to changes in secretion of insulin-like growth factor II (IGF-II) and/or IGF-binding proteins (IGFBPs), which regulate Caco-2 cell proliferation. Cells were incubated in serum-free medium with different concentrations of the individual CLA isomers. t10c12 CLA dose dependently decreased viable cell number (55 +/- 3% reduction 96 h after adding 5 microM t10c12 CLA). t10c12 CLA induced apoptosis and decreased DNA synthesis, whereas c9t11 CLA had no effect. Immunoblot analysis of 24-h serum-free conditioned medium using a monoclonal anti-IGF-II antibody revealed that Caco-2 cells secreted both a mature 7,500 molecular weight (M(r)) IGF-II and higher M(r) forms of IGF-II. The levels of the higher M(r) and the mature form of IGF-II were decreased 50 +/- 3% and 22 +/- 2%, respectively, by 5 microM t10c12 CLA. c9t11 CLA had no effect. Ligand blot analysis of conditioned medium using 125I-labeled IGF-II revealed that t10c12 CLA slightly decreased IGFBP-2 production; c9t11 CLA had no effect. Exogenous IGF-II reversed t10c12 CLA-induced growth inhibition and apoptosis. These results indicate that CLA-inhibited Caco-2 cell growth is caused by t10c12 CLA and may be mediated by decreasing IGF-II secretion in Caco-2 cells.
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Affiliation(s)
- Eun J Kim
- Division of Life Sciences, Hallym University, Chunchon 200-702, Korea
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