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Zhang Y, Tie Q, Bao Z, Shao Z, Zhang L. Inhibition of miR-15a-5p Promotes the Chemoresistance to Pirarubicin in Hepatocellular Carcinoma via Targeting eIF4E. Comput Math Methods Med 2021; 2021:6468405. [PMID: 34812269 PMCID: PMC8605919 DOI: 10.1155/2021/6468405] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/19/2021] [Revised: 10/25/2021] [Accepted: 10/26/2021] [Indexed: 01/10/2023]
Abstract
Chemoresistance has become a primary hurdle in the therapeutic outcome of hepatocellular carcinoma. Substantial evidences have demonstrated that microRNAs (miRNAs) are closely associated with the chemoresistance of hepatocellular carcinoma (HCC). Our investigation is aimed at testifying the influence of microRNA-15a-5p (miR-15a-5p)/eukaryotic translation initiation factor 4E (eIF4E) on hepatocellular carcinoma resistance to pirarubicin (THP). In our study, miR-15a-5p expression was increased in THP-treated HepG2 cells. Downregulation of miR-15a-5p blocked cell growth and elevated cell apoptosis of HepG2 cells treated with THP. Moreover, eIF4E was verified as a direct target of miR-15a-5p by binding its 3'-UTR, which was confirmed by luciferase report experiment. Additionally, eIF4E was negatively associated with the miR-15a-5p expression in HepG2 cells. Mechanically, eIF4E was proven as a specific downstream of miR-15a-5p and mediated the effects of miR-15a-5p on cell viability and apoptosis of HepG2 cells treated with THP. These findings supported that miR-15a-5p facilitated THP resistance of hepatocellular carcinoma cells by modulating eIF4E, thus providing an experimental basis that miR-15a-5p might act as a novel diagnostic target in hepatocellular carcinoma resistance to THP.
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Affiliation(s)
- Ying Zhang
- Jianhu County People's Hospital, Yancheng, 224700 Jiangsu, China
| | - Qingsong Tie
- Jianhu County People's Hospital, Yancheng, 224700 Jiangsu, China
| | - Zhiwei Bao
- Jianhu County People's Hospital, Yancheng, 224700 Jiangsu, China
| | - Zhi Shao
- Jianhu County People's Hospital, Yancheng, 224700 Jiangsu, China
| | - Lan Zhang
- Jianhu County People's Hospital, Yancheng, 224700 Jiangsu, China
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2
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Zhu Y, Wang C, Li M, Yang X. Targeting of MNK/eIF4E overcomes chemoresistance in cervical cancer. J Pharm Pharmacol 2021; 73:1418-1426. [PMID: 34254647 DOI: 10.1093/jpp/rgab094] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2020] [Accepted: 06/07/2021] [Indexed: 11/14/2022]
Abstract
OBJECTIVES Eukaryotic translation initiation factor 4E (eIF4E) is activated in cancers in response to stress. This is regulated by MAP kinase interacting serine/threonine kinase (MNK) in cancerous but not normal cells. Chemoresistance causes treatment failure in advanced cervical cancer. In this study, we addressed chemotherapy effects on eIF4E for cervical cancer and reversal effects by MNK inhibitor cercosporamide for chemo-resistance mitigation. METHODS Cell assays and mouse tumour models were used to determine the efficacy of cercosporamide. Western blotting was applied to understand the affected cell signaling after cercosporamide treatment. KEY FINDINGS Cercosporamide spared normal cervical epithelial cells. On cervical cancer cell lines, it showed inhibition of cell growth and migration, and induced apoptosis. Cercosporamide was effective on chemoresistant cancer cells and augmented the efficiency of doxorubicin and cisplatin both in vitro and in vivo. Cercosporamide suppressed eIF4E signaling. Of note, chemotherapy increased p-eIF4E. Cercosporamide abolished chemotherapy-induced eIF4E activation. The higher level of p-eIF4E in cancer cells compared with normal cervical epithelial cells explains the preferential toxicity of cercosporamide. CONCLUSIONS This work demonstrates the ability of cercosporamide to overcome chemoresistance and highlight preferential inhibition of eIF4E via MNK inhibition in cervical cancer.
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Affiliation(s)
- Yuanyuan Zhu
- Department of Oncology, Xiangyang No.1 People's Hospital, Hubei University of Medicine, Xiangyang, Hubei, China
| | - Changying Wang
- Department of Oncology, Xiangyang No.1 People's Hospital, Hubei University of Medicine, Xiangyang, Hubei, China
| | - Mingqun Li
- Department of Obstetrics and Gynecology, Xiangyang No.1 People's Hospital, Hubei University of Medicine, Xiangyang, Hubei, China
| | - Xiaoyu Yang
- Department of Oncology, Xiangyang No.1 People's Hospital, Hubei University of Medicine, Xiangyang, Hubei, China
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3
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Fang C, Xie H, Zhao J, Wang W, Hou H, Zhang B, Zhou D, Geng X. eIF4E-eIF4G complex inhibition synergistically enhances the effect of sorafenib in hepatocellular carcinoma. Anticancer Drugs 2021; 32:822-828. [PMID: 33783376 PMCID: PMC8366763 DOI: 10.1097/cad.0000000000001074] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2020] [Revised: 03/04/2021] [Indexed: 12/29/2022]
Abstract
The clinical efficacy of sorafenib in hepatocellular carcinoma (HCC) is disappointing due to its low response rate and high rates of adverse effects. The eukaryotic translation initiation factor 4F (eIF4F) complex, mainly consisting of eIF4E-eukaryotic translation initiation factor 4G (eIF4G) interaction, is involved in the induction of drug resistance. Herein, we aimed to demonstrate that eIF4E-eIF4G complex inhibition enhanced the effect of sorafenib. The antiproliferation effect of combined treatment was evaluated by MTT assay and colony formation assay. Flow cytometry was used to detect the early cell apoptosis and cell cycle. The specific mechanism was demonstrated using western blot and lentivirus transfection. The combination of sorafenib with eIF4E-eIF4G inhibitors 4E1RCat (structural) or 4EGI-1 (competitive) synergistically inhibited the cell viability and colony formation ability of HCC cells. Moreover, the combined treatment induced more early apoptosis than sorafenib alone through downregulating the Bcl-2 expression. Besides, the coadministration of sorafenib and 4E1RCat or 4EGI-1 synergistically inhibited the expressions of eIF4E, eIF4G and phospho-4E-BP1 in HCC cells while blocking the phosphorylation of 4E-BP1 with lentiviral transfection failed to increase the sensitivity of HCC cells to sorafenib treatment. PI3K-AKT-mTOR signaling was also inhibited by the combined treatment. In a word, eIF4E-eIF4G complex inhibition synergistically enhances the effect of sorafenib in HCC treatment.
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Affiliation(s)
- Chao Fang
- Department of Hepatobiliary Surgery, The Second Affiliated Hospital of Anhui Medical University
| | - Haishen Xie
- Department of Hepatobiliary Surgery, The Second Affiliated Hospital of Anhui Medical University
| | - Jun Zhao
- Department of Hepatobiliary Surgery, The Second Affiliated Hospital of Anhui Medical University
| | - Weichen Wang
- Department of Hepatobiliary Surgery, The Second Affiliated Hospital of Anhui Medical University
| | - Hui Hou
- Department of Hepatobiliary Surgery, The Second Affiliated Hospital of Anhui Medical University
| | - Bin Zhang
- Department of Hepatobiliary Surgery, The Second Affiliated Hospital of Anhui Medical University
| | - Dachen Zhou
- Department of Hepatobiliary Surgery, The Second Affiliated Hospital of Anhui Medical University
| | - Xiaoping Geng
- Department of Hepatobiliary Surgery, The Second Affiliated Hospital of Anhui Medical University
- Department of Hepatobiliary Surgery, The First Affiliated Hospital of Anhui Medical University, Hefei, Anhui, PR China
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4
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Jacobson BA, Ahmad Z, Chen S, Waldusky G, Dillenburg M, Stoian E, Cambron DA, Patel AJ, Patel MR, Wagner CR, Kratzke RA. 4Ei-10 interdiction of oncogenic cap-mediated translation as therapy for non-small cell lung cancer. Invest New Drugs 2021; 39:636-643. [PMID: 33230623 DOI: 10.1007/s10637-020-01036-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2020] [Accepted: 11/18/2020] [Indexed: 11/28/2022]
Abstract
In order to suppress 5' cap-mediated translation a highly available inhibitor of the interaction between the 5' mRNA cap and the eIF4E complex has been developed. 4Ei-10 is a member of the class of ProTide compounds and has elevated membrane permeability and is a strong active chemical antagonist for eIF4E. Once taken up by cells it is converted by anchimeric activation of the lipophilic 2-(methylthio) ethyl protecting group and after that Hint1 P-N bond cleavage to N7-(p-chlorophenoxyethyl) guanosine 5'-monophosphate (7-Cl-Ph-Ethyl-GMP). Using this powerful interaction, it has been demonstrated that 4Ei-10 inhibits non-small cell lung cancer (NSCLC) cell growth. In addition, treatment of NSCLC cells with 4Ei-10 results in suppression of translation and diminished expression of a cohort of cellular proteins important to maintaining the malignant phenotype and resisting apoptosis such as Bcl-2, survivin, and ornithine decarboxylase (ODC). Finally, as a result of targeting the translation of anti-apoptotic proteins, NSCLC cells are synergized to be more sensitive to the existing anti-neoplastic treatment gemcitabine currently used in NSCLC therapy.
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Affiliation(s)
- Blake A Jacobson
- Department of Medicine, University of Minnesota, Minneapolis, MN, USA
| | - Zeeshan Ahmad
- Department of Medicine, University of Minnesota, Minneapolis, MN, USA
| | | | | | - Maxwell Dillenburg
- Department of Medicinal Chemistry, University of Minnesota, Minneapolis, MN, USA
| | | | | | - Anil J Patel
- Department of Medicine, University of Minnesota, Minneapolis, MN, USA
| | - Manish R Patel
- Department of Medicine, University of Minnesota, Minneapolis, MN, USA
| | - Carston R Wagner
- Department of Medicinal Chemistry, University of Minnesota, Minneapolis, MN, USA
| | - Robert A Kratzke
- Department of Medicine, University of Minnesota, Minneapolis, MN, USA.
- Division of Heme-Onc-Transplant, University of Minnesota Medical School, MMC 480, 420 Delaware St SE, Minneapolis, MN, 55455, USA.
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Gallagher EE, Song JM, Menon A, Mishra LD, Chmiel AF, Garner AL. Consideration of Binding Kinetics in the Design of Stapled Peptide Mimics of the Disordered Proteins Eukaryotic Translation Initiation Factor 4E-Binding Protein 1 and Eukaryotic Translation Initiation Factor 4G. J Med Chem 2019; 62:4967-4978. [PMID: 31033289 PMCID: PMC6679956 DOI: 10.1021/acs.jmedchem.9b00068] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Protein disorder plays a crucial role in signal transduction and is key for many cellular processes including transcription, translation, and cell cycle. Within the intrinsically disordered protein interactome, the α-helix is commonly used for binding, which is induced via a disorder-to-order transition. Because the targeting of protein-protein interactions (PPIs) remains an important challenge in medicinal chemistry, efforts have been made to mimic this secondary structure for rational inhibitor design through the use of stapled peptides. Cap-dependent mRNA translation is regulated by two disordered proteins, 4E-BP1 and eIF4G, that inhibit or stimulate the activity of the m7G cap-binding translation initiation factor, eIF4E, respectively. Both use an α-helical motif for eIF4E binding, warranting the investigation of stapled peptide mimics for manipulating eIF4E PPIs. Herein, we describe our efforts toward this goal, resulting in the synthesis of a cell-active stapled peptide for further development in manipulating aberrant cap-dependent translation in human diseases.
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Affiliation(s)
- Erin E Gallagher
- Department of Medicinal Chemistry, College of Pharmacy , University of Michigan , 1600 Huron Parkway, NCRC B520 , Ann Arbor , Michigan 48109 , United States
| | - James M Song
- Program in Chemical Biology , University of Michigan , 210 Washtenaw Avenue , Ann Arbor , Michigan 48109 , United States
| | - Arya Menon
- Department of Medicinal Chemistry, College of Pharmacy , University of Michigan , 1600 Huron Parkway, NCRC B520 , Ann Arbor , Michigan 48109 , United States
| | - Lauren D Mishra
- Department of Medicinal Chemistry, College of Pharmacy , University of Michigan , 1600 Huron Parkway, NCRC B520 , Ann Arbor , Michigan 48109 , United States
| | - Alyah F Chmiel
- Department of Medicinal Chemistry, College of Pharmacy , University of Michigan , 1600 Huron Parkway, NCRC B520 , Ann Arbor , Michigan 48109 , United States
| | - Amanda L Garner
- Department of Medicinal Chemistry, College of Pharmacy , University of Michigan , 1600 Huron Parkway, NCRC B520 , Ann Arbor , Michigan 48109 , United States
- Program in Chemical Biology , University of Michigan , 210 Washtenaw Avenue , Ann Arbor , Michigan 48109 , United States
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6
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Lucchesi CA, Zhang J, Ma B, Chen M, Chen X. Disruption of the Rbm38-eIF4E Complex with a Synthetic Peptide Pep8 Increases p53 Expression. Cancer Res 2019; 79:807-818. [PMID: 30591552 PMCID: PMC6377842 DOI: 10.1158/0008-5472.can-18-2209] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2018] [Revised: 11/05/2018] [Accepted: 12/18/2018] [Indexed: 02/07/2023]
Abstract
Rbm38 is a p53 target and an RNA-binding protein known to suppress p53 translation by preventing eukaryotic translation initiation factor 4E (eIF4E) from binding to p53 mRNA. In this study, we show that synthetic peptides corresponding to the binding interface between Rbm38 and eIF4E, including an 8 amino acid peptide (Pep8) derived from Rbm38, are effective in relieving Rbm38-mediated repression of p53. Molecular simulations showed that Ser-6 in Pep8 forms a hydrogen bond with Asp-202 in eIF4E. Substitution of Ser-6 with Lys, but not with Asp, enhanced the ability of Pep8 to inhibit the Rbm38-eIF4E complex. Importantly, Pep8 alone or together with a low dose of doxorubicin potently induced p53 expression and suppressed colony and tumor sphere formation and xenograft tumors in Rbm38- and p53-dependent manners. Together, we conclude that modulating the Rbm38-eIF4E complex may be explored as a therapeutic strategy for cancers that carry wild-type p53. SIGNIFICANCE: Disruption of the Rbm38-eIF4E complex via synthetic peptides induces wild-type p53 expression, suppresses tumor growth and progression, and may serve as a novel cancer therapeutic strategy.
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Affiliation(s)
- Christopher A Lucchesi
- Comparative Oncology Laboratory, Schools of Veterinary Medicine and Medicine, University of California, Davis, Davis, California
| | - Jin Zhang
- Comparative Oncology Laboratory, Schools of Veterinary Medicine and Medicine, University of California, Davis, Davis, California
| | - Buyong Ma
- Basic Science Program, Leidos Biomedical Research, Inc., Cancer and Inflammation Program, National Cancer Institute, Frederick, Maryland
| | - Mingyi Chen
- Department of Pathology, UT Southwestern Medical Center, Dallas, Texas
| | - Xinbin Chen
- Comparative Oncology Laboratory, Schools of Veterinary Medicine and Medicine, University of California, Davis, Davis, California.
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Ruibin W, Zheng X, Chen J, Zhang X, Yang X, Lin Y. Micro RNA-1298 opposes the effects of chronic oxidative stress on human trabecular meshwork cells via targeting on EIF4E3. Biomed Pharmacother 2018; 100:349-357. [PMID: 29453044 DOI: 10.1016/j.biopha.2018.02.001] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2017] [Revised: 01/23/2018] [Accepted: 02/02/2018] [Indexed: 02/05/2023] Open
Abstract
OBJECTIVE This study aimed to investigate the effect and potential mechanism of miR-1298 in the progression of human trabecular meshwork (HTM) cells. MATERIAL AND METHODS Expression of miR-1298 was assessed by quantitative real time PCR (qRT-PCR), as well as in HTM-1 and HTM-2 cells. Mature miR-1298 mimic, miR-1298 inhibitor, and si-EIF4E3 and their corresponding controls were transfected into HTM-1 and HTM-2 to obtain stable HTM cells. Luciferase reporter assay was used to verify regulation between miR-1298 and EIF4E3. Cytotoxicity and Oxidative damage were assessed using commercial kits, and apoptosis was determined using flow cytometry. ECM and apoptosis related factors were determined using qRT-PCR and western blotting, as well as the pathway related factors. RESULTS The expression of miR-1298 was significantly decreased both in glaucoma and HTM cells. MiR-1298 mimic could significantly inhibit the increase of cytotoxicity, apoptosis, accumulation of carbonylated proteins and ECM induced by COS, but miR-1298 inhibitor could obviously promote the increase effects caused by COS in HTM cells. EIF4E3 was a downstream target of miR-1298. Sliced EIF4E3 could significantly inhibit the increase effects induced miR-1298 inhibitor in HTM cells under COS. The expression levels of TGF-β2 and Smad4 were significantly increased, and Wnt3a and β-cantenin were obviously decreased under COS, and miR-1298 inhibitor could markedly promote this increase effect, while sliced EIF4E3 could reverse the effect of miR-1298 under COS. CONCLUSIONS miR-1298 could protect HTM cells to against damage caused by COS via inhibiting TGF-β2/Smad4 pathway and activating canonical Wnt pathway.
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Affiliation(s)
- Wu Ruibin
- Department of Ophthalmolog, The First Affiliated Hospital of Shantou University Medical College, Shantou, Guangdong, 515000, China.
| | - Xiaowei Zheng
- Department of Ophthalmolog, The First Affiliated Hospital of Shantou University Medical College, Shantou, Guangdong, 515000, China
| | - Jiaying Chen
- Department of Ophthalmolog, The First Affiliated Hospital of Shantou University Medical College, Shantou, Guangdong, 515000, China
| | - Xinyi Zhang
- Department of Ophthalmolog, The First Affiliated Hospital of Shantou University Medical College, Shantou, Guangdong, 515000, China
| | - Xiayin Yang
- Department of Ophthalmolog, The First Affiliated Hospital of Shantou University Medical College, Shantou, Guangdong, 515000, China
| | - Yuxian Lin
- Department of Ophthalmolog, The First Affiliated Hospital of Shantou University Medical College, Shantou, Guangdong, 515000, China
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8
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Jin S, Chang IH, Kim JW, Whang YM, Kim HJ, Hong SA, Lee TJ. Identification of Downstream Genes of the mTOR Pathway that Predict Recurrence and Progression in Non-Muscle Invasive High-Grade Urothelial Carcinoma of the Bladder. J Korean Med Sci 2017; 32:1327-1336. [PMID: 28665070 PMCID: PMC5494333 DOI: 10.3346/jkms.2017.32.8.1327] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/18/2017] [Accepted: 05/13/2017] [Indexed: 12/23/2022] Open
Abstract
Microarray analysis was used to investigate the lack of identified mammalian target of rapamycin (mTOR) pathway downstream genes to overcome cross-talk at non-muscle invasive high-grade (HG)-urothelial carcinoma (UC) of the bladder, gene expression patterns, gene ontology, and gene clustering by triple (p70S6K, S6K, and eIF4E) small interfering RNAs (siRNAs) or rapamycin in 5637 and T24 cell lines. We selected mTOR pathway downstream genes that were suppressed by siRNAs more than 2-fold, or were up-regulated or down-regulated by rapamycin more than 2-fold. We validated mTOR downstream genes with immunohistochemistry using a tissue microarray (TMA) of 125 non-muscle invasive HG-UC patients and knockout study to evaluate the synergistic effect with rapamycin. The microarray analysis selected mTOR pathway downstream genes consisting of 4 rapamycin up-regulated genes (FABP4, H19, ANXA10, and UPK3A) and 4 rapamycin down-regulated genes (FOXD3, ATP7A, plexin D1, and ADAMTS5). In the TMA, FABP4, and ATP7A were more expressed at T1 and FOXD3 was at Ta. ANXA10 and ADAMTS5 were more expressed in tumors ≤ 3 cm in diameter. In a multivariate Cox regression model, ANXA10 was a significant predictor of recurrence and ATP7A was a significant predictor of progression in non-muscle invasive HG-UC of the bladder. In an ATP7A knock-out model, rapamycin treatment synergistically inhibited cell viability, wound healing, and invasion ability compared to rapamycin only. Activity of the ANXA10 and ATP7A mTOR pathway downstream genes might predict recurrence and progression in non-muscle invasive HG-UC of the bladder. ATP7A knockout overcomes rapamycin cross-talk.
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Affiliation(s)
- Subin Jin
- Department of Urology, Chung-Ang University College of Medicine, Seoul, Korea
| | - In Ho Chang
- Department of Urology, Chung-Ang University College of Medicine, Seoul, Korea
| | - Jin Wook Kim
- Department of Urology, Chung-Ang University College of Medicine, Seoul, Korea
| | - Young Mi Whang
- Department of Urology, Chung-Ang University College of Medicine, Seoul, Korea
| | - Ha Jeong Kim
- Department of Agricultural Biology, National Academy of Agricultural Science, Rural Development Administration, Jeonju, Korea
| | - Soon Auck Hong
- Department of Pathology, Soonchunhyang University College of Medicine, Cheonan, Korea
| | - Tae Jin Lee
- Department of Pathology, Chung-Ang University College of Medicine, Seoul, Korea.
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9
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Lahr RM, Fonseca BD, Ciotti GE, Al-Ashtal HA, Jia JJ, Niklaus MR, Blagden SP, Alain T, Berman AJ. La-related protein 1 (LARP1) binds the mRNA cap, blocking eIF4F assembly on TOP mRNAs. eLife 2017; 6:e24146. [PMID: 28379136 PMCID: PMC5419741 DOI: 10.7554/elife.24146] [Citation(s) in RCA: 112] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2016] [Accepted: 04/04/2017] [Indexed: 01/07/2023] Open
Abstract
The 5'terminal oligopyrimidine (5'TOP) motif is a cis-regulatory RNA element located immediately downstream of the 7-methylguanosine [m7G] cap of TOP mRNAs, which encode ribosomal proteins and translation factors. In eukaryotes, this motif coordinates the synchronous and stoichiometric expression of the protein components of the translation machinery. La-related protein 1 (LARP1) binds TOP mRNAs, regulating their stability and translation. We present crystal structures of the human LARP1 DM15 region in complex with a 5'TOP motif, a cap analog (m7GTP), and a capped cytidine (m7GpppC), resolved to 2.6, 1.8 and 1.7 Å, respectively. Our binding, competition, and immunoprecipitation data corroborate and elaborate on the mechanism of 5'TOP motif binding by LARP1. We show that LARP1 directly binds the cap and adjacent 5'TOP motif of TOP mRNAs, effectively impeding access of eIF4E to the cap and preventing eIF4F assembly. Thus, LARP1 is a specialized TOP mRNA cap-binding protein that controls ribosome biogenesis.
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Affiliation(s)
- Roni M Lahr
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, United States
| | - Bruno D Fonseca
- Children’s Hospital of Eastern Ontario Research Institute, Ottawa, Canada
| | - Gabrielle E Ciotti
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, United States
| | - Hiba A Al-Ashtal
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, United States
| | - Jian-Jun Jia
- Children’s Hospital of Eastern Ontario Research Institute, Ottawa, Canada
| | - Marius R Niklaus
- Children’s Hospital of Eastern Ontario Research Institute, Ottawa, Canada
| | - Sarah P Blagden
- Department of Oncology, University of Oxford, Oxford, United Kingdom
| | - Tommy Alain
- Children’s Hospital of Eastern Ontario Research Institute, Ottawa, Canada
| | - Andrea J Berman
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, United States
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10
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Abstract
Translational control plays a critical role in the regulation of gene expression in eukaryotes and affects many essential cellular processes, including proliferation, apoptosis and differentiation. Under most circumstances, translational control occurs at the initiation step at which the ribosome is recruited to the mRNA. The eukaryotic translation initiation factor 4E (eIF4E), as part of the eIF4F complex, interacts first with the mRNA and facilitates the recruitment of the 40S ribosomal subunit. The activity of eIF4E is regulated at many levels, most profoundly by two major signalling pathways: PI3K (phosphoinositide 3-kinase)/Akt (also known and Protein Kinase B, PKB)/mTOR (mechanistic/mammalian target of rapamycin) and Ras (rat sarcoma)/MAPK (mitogen-activated protein kinase)/Mnk (MAPK-interacting kinases). mTOR directly phosphorylates the 4E-BPs (eIF4E-binding proteins), which are inhibitors of eIF4E, to relieve translational suppression, whereas Mnk phosphorylates eIF4E to stimulate translation. Hyperactivation of these pathways occurs in the majority of cancers, which results in increased eIF4E activity. Thus, translational control via eIF4E acts as a convergence point for hyperactive signalling pathways to promote tumorigenesis. Consequently, recent works have aimed to target these pathways and ultimately the translational machinery for cancer therapy.
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Affiliation(s)
- Nadeem Siddiqui
- Department of Biochemistry and Goodman Cancer Research Centre, McGill University, 1160 Pine Avenue West, Montreal, Quebec, Canada H3A 1A3
| | - Nahum Sonenberg
- Department of Biochemistry and Goodman Cancer Research Centre, McGill University, 1160 Pine Avenue West, Montreal, Quebec, Canada H3A 1A3
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11
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Wiegering A, Uthe FW, Jamieson T, Ruoss Y, Hüttenrauch M, Küspert M, Pfann C, Nixon C, Herold S, Walz S, Taranets L, Germer CT, Rosenwald A, Sansom OJ, Eilers M. Targeting Translation Initiation Bypasses Signaling Crosstalk Mechanisms That Maintain High MYC Levels in Colorectal Cancer. Cancer Discov 2015; 5:768-781. [PMID: 25934076 PMCID: PMC5166973 DOI: 10.1158/2159-8290.cd-14-1040] [Citation(s) in RCA: 69] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2014] [Accepted: 04/29/2015] [Indexed: 11/16/2022]
Abstract
UNLABELLED Deregulated expression of MYC is a driver of colorectal carcinogenesis, suggesting that inhibiting MYC may have significant therapeutic value. The PI3K and mTOR pathways control MYC turnover and translation, respectively, providing a rationale to target both pathways to inhibit MYC. Surprisingly, inhibition of PI3K does not promote MYC turnover in colon carcinoma cells, but enhances MYC expression because it promotes FOXO-dependent expression of growth factor receptors and MAPK-dependent transcription of MYC. Inhibition of mTOR fails to inhibit translation of MYC, because levels of 4EBPs are insufficient to fully sequester eIF4E and because an internal ribosomal entry site element in the 5'-untranslated region of the MYC mRNA permits translation independent of eIF4E. A small-molecule inhibitor of the translation factor eIF4A, silvestrol, bypasses the signaling feedbacks, reduces MYC translation, and inhibits tumor growth in a mouse model of colorectal tumorigenesis. We propose that targeting translation initiation is a promising strategy to limit MYC expression in colorectal tumors. SIGNIFICANCE Inhibiting MYC function is likely to have a significant therapeutic impact in colorectal cancers. Here, we explore several strategies to target translation initiation in order to block MYC expression. We show that a small-molecule inhibitor of eIF4A inhibits MYC expression and suppresses tumor growth in vivo.
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Affiliation(s)
- Armin Wiegering
- Theodor Boveri Institute, Biocenter, University of Würzburg, Am Hubland, 97074 Würzburg, Germany
- University Hospital Würzburg, Department of General, Visceral, Vascular and Pediatric Surgery, Würzburg, Germany
| | - Friedrich W. Uthe
- Theodor Boveri Institute, Biocenter, University of Würzburg, Am Hubland, 97074 Würzburg, Germany
| | - Thomas Jamieson
- CRUK Beatson Institute, Garscube Estate, Switchback Road, Glasgow, G61 1BD, UK
| | - Yvonne Ruoss
- Theodor Boveri Institute, Biocenter, University of Würzburg, Am Hubland, 97074 Würzburg, Germany
| | - Melanie Hüttenrauch
- Theodor Boveri Institute, Biocenter, University of Würzburg, Am Hubland, 97074 Würzburg, Germany
| | - Maritta Küspert
- Department of Biochemistry, Biocenter, University of Würzburg, Am Hubland, 97074 Würzburg, Germany
| | - Christina Pfann
- Theodor Boveri Institute, Biocenter, University of Würzburg, Am Hubland, 97074 Würzburg, Germany
| | - Colin Nixon
- CRUK Beatson Institute, Garscube Estate, Switchback Road, Glasgow, G61 1BD, UK
| | - Steffi Herold
- Theodor Boveri Institute, Biocenter, University of Würzburg, Am Hubland, 97074 Würzburg, Germany
| | - Susanne Walz
- Theodor Boveri Institute, Biocenter, University of Würzburg, Am Hubland, 97074 Würzburg, Germany
- Comprehensive Cancer Center Mainfranken, University of Würzburg, Josef-Schneider-Str. 6, 97080 Würzburg, Germany
| | - Lyudmyla Taranets
- Comprehensive Cancer Center Mainfranken, University of Würzburg, Josef-Schneider-Str. 6, 97080 Würzburg, Germany
| | - Christoph-Thomas Germer
- University Hospital Würzburg, Department of General, Visceral, Vascular and Pediatric Surgery, Würzburg, Germany
- Comprehensive Cancer Center Mainfranken, University of Würzburg, Josef-Schneider-Str. 6, 97080 Würzburg, Germany
| | - Andreas Rosenwald
- Comprehensive Cancer Center Mainfranken, University of Würzburg, Josef-Schneider-Str. 6, 97080 Würzburg, Germany
- Institute of Pathology, University of Würzburg, Josef-Schneider-Strasse 2, 97080 Würzburg, Germany
| | - Owen J Sansom
- CRUK Beatson Institute, Garscube Estate, Switchback Road, Glasgow, G61 1BD, UK
| | - Martin Eilers
- Theodor Boveri Institute, Biocenter, University of Würzburg, Am Hubland, 97074 Würzburg, Germany
- Comprehensive Cancer Center Mainfranken, University of Würzburg, Josef-Schneider-Str. 6, 97080 Würzburg, Germany
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12
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Chi BH, Kim SJ, Seo HK, Seo HH, Lee SJ, Kwon JK, Lee TJ, Chang IH. P70S6K and Elf4E dual inhibition is essential to control bladder tumor growth and progression in orthotopic mouse non-muscle invasive bladder tumor model. J Korean Med Sci 2015; 30:308-16. [PMID: 25729255 PMCID: PMC4330487 DOI: 10.3346/jkms.2015.30.3.308] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/02/2014] [Accepted: 11/10/2014] [Indexed: 11/20/2022] Open
Abstract
We investigated how the dual inhibition of the molecular mechanism of the mammalian target of the rapamycin (mTOR) downstreams, P70S6 kinase (P70S6K) and eukaryotic initiation factor 4E (eIF4E), can lead to a suppression of the proliferation and progression of urothelial carcinoma (UC) in an orthotopic mouse non-muscle invasive bladder tumor (NMIBT) model. A KU-7-luc cell intravesically instilled orthotopic mouse NMIBC model was monitored using bioluminescence imaging (BLI) in vivo by interfering with different molecular components using rapamycin and siRNA technology. We then analyzed the effects on molecular activation status, cell growth, proliferation, and progression. A high concentration of rapamycin (10 µM) blocked both P70S6K and elF4E phosphorylation and inhibited cell proliferation in the KU-7-luc cells. It also reduced cell viability and proliferation more than the transfection of siRNA against p70S6K or elF4E. The groups with dual p70S6K and elF4E siRNA, and rapamycin reduced tumor volume and lamina propria invasion more than the groups with p70S6K or elF4E siRNA instillation, although all groups reduced photon density compared to the control. These findings suggest that both the mTOR pathway downstream of eIF4E and p70S6K can be successfully inhibited by high dose rapamycin only, and p70S6K and Elf4E dual inhibition is essential to control bladder tumor growth and progression.
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Affiliation(s)
- Byung Hoon Chi
- Department of Urology, Chung-Ang University College of Medicine, Seoul, Korea
| | - Soon-Ja Kim
- Biomedical Science, Department of Medicine, Chung-Ang University Graduate School, Seoul, Korea
| | - Ho Kyung Seo
- Center for Prostate Cancer, Research Institute, National Cancer Center, Goyang, Korea
| | - Hye-Hyun Seo
- Genitourinary Cancer Branch, Research Institute, National Cancer Center, Goyang, Korea
| | - Sang-Jin Lee
- Genitourinary Cancer Branch, Research Institute, National Cancer Center, Goyang, Korea
| | - Jong Kyou Kwon
- Department of Urology, Chung-Ang University College of Medicine, Seoul, Korea
| | - Tae-Jin Lee
- Department of Pathology, Chung-Ang University College of Medicine, Seoul, Korea
| | - In Ho Chang
- Department of Urology, Chung-Ang University College of Medicine, Seoul, Korea
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13
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Oridate N, Kim HJ, Xu X, Lotan R. Growth inhibition of head and neck squamous carcinoma cells by small interfering RNAs targeting eIF4E or cyclin D1 alone or combined with cisplatin. Cancer Biol Ther 2014; 4:318-23. [PMID: 15846092 DOI: 10.4161/cbt.4.3.1504] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Head and neck squamous cell carcinomas (HNSCCs) exhibit an increased expression of the translation initiation factor eIF4E and the cell-cycle regulator cyclin D1 (CCND1). Both stimulate cell cycle progression and transform squamous epithelial cells. We used small interfering RNAs (siRNAs) to silence the expression of eIF4E and CCND1 in HNSCC UMSCC22B cells and analyzed the effects of reduced levels of these proteins on colony formation. Transfection of either eIF4E or CCND1 siRNAs decreased the levels of their targeted proteins and inhibited cell growth. siRNA-mediated decrease of eIF4E has led to decreases in the expression of CCND1, basic fibroblast growth factor and vascular endothelial growth factor. Combination of these siRNAs and cisplatin showed more than additive inhibition of colony formation. These findings demonstrate that siRNA silencing of either eIF4E or CCND1 leads to inhibition of the growth of HNSCC cells and suggest that these siRNAs alone or combined with conventional cytotoxic agents may be useful for therapy of HNSCCs.
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Affiliation(s)
- Nobuhiko Oridate
- Department of Thoracic/Head and Neck Medicical Oncology, The University of Texas M.D. Anderson Cancer Center, Houston, Texas 77030-4095, USA
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14
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Jacobson BA, Thumma SC, Jay-Dixon J, Patel MR, Dubear Kroening K, Kratzke MG, Etchison RG, Konicek BW, Graff JR, Kratzke RA. Targeting eukaryotic translation in mesothelioma cells with an eIF4E-specific antisense oligonucleotide. PLoS One 2013; 8:e81669. [PMID: 24260583 PMCID: PMC3832430 DOI: 10.1371/journal.pone.0081669] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2013] [Accepted: 10/17/2013] [Indexed: 12/25/2022] Open
Abstract
BACKGROUND Aberrant cap-dependent translation is implicated in tumorigenesis in multiple tumor types including mesothelioma. In this study, disabling the eIF4F complex by targeting eIF4E with eIF4E-specific antisense oligonucleotide (4EASO) is assessed as a therapy for mesothelioma. METHODS Mesothelioma cells were transfected with 4EASO, designed to target eIF4E mRNA, or mismatch-ASO control. Cell survival was measured in mesothelioma treated with 4EASO alone or combined with either gemcitabine or pemetrexed. Levels of eIF4E, ODC, Bcl-2 and β-actin were assessed following treatment. Binding to a synthetic cap-analogue was used to study the strength of eIF4F complex activation following treatment. RESULTS eIF4E level and the formation of eIF4F cap-complex decreased in response to 4EASO, but not mismatch control ASO, resulting in cleavage of PARP indicating apoptosis. 4EASO treatment resulted in dose dependent decrease in eIF4E levels, which corresponded to cytotoxicity of mesothelioma cells. 4EASO resulted in decreased levels of eIF4E in non-malignant LP9 cells, but this did not correspond to increased cytotoxicity. Proteins thought to be regulated by cap-dependent translation, Bcl-2 and ODC, were decreased upon treatment with 4EASO. Combination therapy of 4EASO with pemetrexed or gemcitabine further reduced cell number. CONCLUSION 4EASO is a novel drug that causes apoptosis and selectively reduces eIF4E levels, eIF4F complex formation, and proliferation of mesothelioma cells. eIF4E knockdown results in decreased expression of anti-apoptotic and pro-growth proteins and enhances chemosensitivity.
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Affiliation(s)
- Blake A. Jacobson
- Department of Medicine, University of Minnesota, Minneapolis, Minnesota, United States of America
| | - Saritha C. Thumma
- Department of Medicine, University of Minnesota, Minneapolis, Minnesota, United States of America
| | - Joseph Jay-Dixon
- Department of Medicine, University of Minnesota, Minneapolis, Minnesota, United States of America
| | - Manish R. Patel
- Department of Medicine, University of Minnesota, Minneapolis, Minnesota, United States of America
| | - K. Dubear Kroening
- Department of Biological Sciences, University of Wisconsin-Fox Valley, Menasha, Wisconsin, United States of America
| | - Marian G. Kratzke
- Research Service, Minneapolis Veterans Affairs Medical Center, Minneapolis, Minnesota, United States of America
| | - Ryan G. Etchison
- Department of Medicine, University of Minnesota, Minneapolis, Minnesota, United States of America
| | - Bruce W. Konicek
- Lilly Research Laboratories, Eli Lilly and Company, Indianapolis, Indiana, United States of America
| | - Jeremy R. Graff
- Lilly Research Laboratories, Eli Lilly and Company, Indianapolis, Indiana, United States of America
| | - Robert A. Kratzke
- Department of Medicine, University of Minnesota, Minneapolis, Minnesota, United States of America
- * E-mail:
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15
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Nasr Z, Dow LE, Paquet M, Chu J, Ravindar K, Somaiah R, Deslongchamps P, Porco Jr JA, Lowe SW, Pelletier J. Suppression of eukaryotic initiation factor 4E prevents chemotherapy-induced alopecia. BMC Pharmacol Toxicol 2013; 14:58. [PMID: 24219888 PMCID: PMC4225821 DOI: 10.1186/2050-6511-14-58] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2013] [Accepted: 11/08/2013] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Chemotherapy-induced hair loss (alopecia) (CIA) is one of the most feared side effects of chemotherapy among cancer patients. There is currently no pharmacological approach to minimize CIA, although one strategy that has been proposed involves protecting normal cells from chemotherapy by transiently inducing cell cycle arrest. Proof-of-concept for this approach, known as cyclotherapy, has been demonstrated in cell culture settings. METHODS The eukaryotic initiation factor (eIF) 4E is a cap binding protein that stimulates ribosome recruitment to mRNA templates during the initiation phase of translation. Suppression of eIF4E is known to induce cell cycle arrest. Using a novel inducible and reversible transgenic mouse model that enables RNAi-mediated suppression of eIF4E in vivo, we assessed the consequences of temporal eIF4E suppression on CIA. RESULTS Our results demonstrate that transient inhibition of eIF4E protects against cyclophosphamide-induced alopecia at the organismal level. At the cellular level, this protection is associated with an accumulation of cells in G1, reduced apoptotic indices, and was phenocopied using small molecule inhibitors targeting the process of translation initiation. CONCLUSIONS Our data provide a rationale for exploring suppression of translation initiation as an approach to prevent or minimize cyclophosphamide-induced alopecia.
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Affiliation(s)
- Zeina Nasr
- Departments of Biochemistry, McGill University, Montreal, Quebec H3G 1Y6, Canada
| | - Lukas E Dow
- Memorial Sloan-Kettering Cancer Center, New York, USA
| | - Marilene Paquet
- Département de Pathologie et de Microbiologie, Faculté de Médecine Vétérinaire, Université de Montréal, Saint-Hyacinthe, Québec J2S 2 M2, Canada
| | - Jennifer Chu
- Departments of Biochemistry, McGill University, Montreal, Quebec H3G 1Y6, Canada
| | - Kontham Ravindar
- Départment de Chimie, Université Laval, Ste-Foy, Quebec G1V 0A6, Canada
| | - Ragam Somaiah
- Départment de Chimie, Université Laval, Ste-Foy, Quebec G1V 0A6, Canada
| | | | - John A Porco Jr
- Center for Methodology and Library Development, Boston University, 590 Commonwealth Ave., Boston, MA 02215, USA
| | - Scott W Lowe
- Memorial Sloan-Kettering Cancer Center, New York, USA
- Howard Hughes Medical Institute, New York, NY 10065, USA
| | - Jerry Pelletier
- Departments of Biochemistry, McGill University, Montreal, Quebec H3G 1Y6, Canada
- Department of Oncology, McGill University, Montreal, Quebec H3G 1Y6, Canada
- The Rosalind and Morris Goodman Cancer Research Center, McGill University, Montreal, Quebec H3G 1Y6, Canada
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16
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Redondo N, García-Moreno M, Sanz MA, Carrasco L. Translation of viral mRNAs that do not require eIF4E is blocked by the inhibitor 4EGI-1. Virology 2013; 444:171-80. [PMID: 23870416 PMCID: PMC7111898 DOI: 10.1016/j.virol.2013.06.008] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2013] [Revised: 03/31/2013] [Accepted: 06/07/2013] [Indexed: 11/18/2022]
Abstract
High throughput screening has rendered new inhibitors of eukaryotic protein synthesis. One such molecule, 4EGI-1 has been reported to selectively block the initiation factor eIF4E. We have investigated the action of this inhibitor on translation directed by several viral mRNAs which, in principle, do not utilize eIF4E. We found that 4EGI-1 inhibits translation directed by poliovirus IRES, in rabbit reticulocyte lysates, to a similar extent as capped mRNA. Moreover, 4EGI-1 inhibits translation driven by poliovirus IRES, both in vitro and in cultured cells, despite cleavage of eIF4G by picornavirus proteases. Finally, translation of vesicular stomatitis virus mRNAs and Sindbis virus subgenomic mRNA is blocked by 4EGI-1 in infected cells to a similar extent as cellular mRNAs. These findings cast doubt on the selective action of this inhibitor, and suggest that this molecule may affect other steps in protein synthesis unrelated to cap recognition by eIF4E.
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Affiliation(s)
- Natalia Redondo
- Centro de Biología Molecular Severo Ochoa (CSIC-UAM), c/Nicolás Cabrera, 1 Universidad Autónoma de Madrid, Cantoblanco 28049, Madrid, Spain.
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17
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Bollmann F, Fechir K, Nowag S, Koch K, Art J, Kleinert H, Pautz A. Human inducible nitric oxide synthase (iNOS) expression depends on chromosome region maintenance 1 (CRM1)- and eukaryotic translation initiation factor 4E (elF4E)-mediated nucleocytoplasmic mRNA transport. Nitric Oxide 2013; 30:49-59. [PMID: 23471078 DOI: 10.1016/j.niox.2013.02.083] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2012] [Revised: 02/15/2013] [Accepted: 02/25/2013] [Indexed: 12/31/2022]
Abstract
Human inducible nitric oxide synthase (iNOS) is regulated on the expressional level mostly by post-transcriptional mechanisms modulating the mRNA stability. Another important step in the control of eukaryotic gene expression is the nucleocytoplasmic mRNA transport. Most cellular mRNAs are exported via the TAP/Nxt complex of proteins. However, some mRNAs are transported by a different mechanism involving the nuclear export receptor CRM1. Treatment of DLD-1 cells with the CRM1 inhibitor leptomycin B (LMB) or anti-CRM1 siRNAs reduced cytokine-induced iNOS expression. We could demonstrate that the iNOS mRNA is exported from the nucleus in a CRM1-dependent manner. Since CRM1 itself does not possess any RNA binding affinity, an adapter protein is needed to mediate CRM1-dependent mRNA export. Western blot experiments showed that the eukaryotic translation initiation factor eIF4E is retained in the nucleus after LMB treatment. Blockade of eIF4E by ribavirin or overexpression of the promyelocytic leukemia protein (PML) decreased iNOS expression due to reduced iNOS mRNA export from the nucleus. Transfection experiments provide evidence that the 3'-untranslated region of the iNOS mRNA is involved in eIF4E-mediated iNOS mRNA transport. In summary, CRM1 and eIF4E seem to play an important role in the nucleocytoplasmic export of human iNOS mRNA.
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Affiliation(s)
- Franziska Bollmann
- Department of Pharmacology, University Medical Center of the Johannes Gutenberg University Mainz, D 55101 Mainz, Germany
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18
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Pettersson F, Yau C, Dobocan MC, Culjkovic-Kraljacic B, Retrouvey H, Puckett R, Flores LM, Krop IE, Rousseau C, Cocolakis E, Borden KLB, Benz CC, Miller WH. Ribavirin treatment effects on breast cancers overexpressing eIF4E, a biomarker with prognostic specificity for luminal B-type breast cancer. Clin Cancer Res 2011; 17:2874-84. [PMID: 21415224 DOI: 10.1158/1078-0432.ccr-10-2334] [Citation(s) in RCA: 99] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
PURPOSE We have evaluated the eukaryotic translation initiation factor 4E (eIF4E) as a potential biomarker and therapeutic target in breast cancer. eIF4E facilitates nuclear export and translation of specific, growth-stimulatory mRNAs and is frequently overexpressed in cancer. EXPERIMENTAL DESIGN Breast cancer cells were treated with ribavirin, an inhibitor of eIF4E, and effects on cell proliferation and on known mRNA targets of eIF4E were determined. eIF4E expression was assessed, at the mRNA and protein level, in breast cancer cell lines and in skin biopsies from patients with metastatic disease. Additionally, pooled microarray data from 621 adjuvant untreated, node-negative breast cancers were analyzed for eIF4E expression levels and correlation with distant metastasis-free survival (DMFS), overall and within each intrinsic breast cancer subtype. RESULTS At clinically relevant concentrations, ribavirin reduced cell proliferation and suppressed clonogenic potential, correlating with reduced mRNA export and protein expression of important eIF4E targets. This effect was suppressed by knockdown of eIF4E. Although eIF4E expression is elevated in all breast cancer cell lines, variability in ribavirin responsiveness was observed, indicating that other factors contribute to an eIF4E-dependent phenotype. Assessment of the prognostic value of high eIF4E mRNA in patient tumors found that significant discrimination between good and poor outcome groups was observed only in luminal B cases, suggesting that a specific molecular profile may predict response to eIF4E-targeted therapy. CONCLUSIONS Inhibition of eIF4E is a potential breast cancer therapeutic strategy that may be especially promising against specific molecular subtypes and in metastatic as well as primary tumors.
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MESH Headings
- Antimetabolites, Antineoplastic/pharmacology
- Antimetabolites, Antineoplastic/therapeutic use
- Biomarkers, Tumor/genetics
- Biomarkers, Tumor/metabolism
- Breast Neoplasms/classification
- Breast Neoplasms/diagnosis
- Breast Neoplasms/drug therapy
- Breast Neoplasms/genetics
- Carcinoma/classification
- Carcinoma/diagnosis
- Carcinoma/drug therapy
- Carcinoma/genetics
- Cell Line, Tumor
- Cells, Cultured
- Eukaryotic Initiation Factor-4E/antagonists & inhibitors
- Eukaryotic Initiation Factor-4E/genetics
- Eukaryotic Initiation Factor-4E/metabolism
- Female
- Gene Expression Regulation, Neoplastic/drug effects
- Gene Knockdown Techniques
- Humans
- Mammary Glands, Human/metabolism
- Mammary Glands, Human/pathology
- Organ Specificity/genetics
- Prognosis
- RNA, Small Interfering/pharmacology
- Ribavirin/pharmacology
- Ribavirin/therapeutic use
- Up-Regulation/drug effects
- Up-Regulation/genetics
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Affiliation(s)
- Filippa Pettersson
- Lady Davis Institute & Segal Cancer Centre of the Jewish General Hospital, McGill University, Montréal, Canada
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19
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Ghosh B, Benyumov AO, Ghosh P, Jia Y, Avdulov S, Dahlberg PS, Peterson M, Smith K, Polunovsky VA, Bitterman PB, Wagner CR. Nontoxic chemical interdiction of the epithelial-to-mesenchymal transition by targeting cap-dependent translation. ACS Chem Biol 2009; 4:367-77. [PMID: 19351181 PMCID: PMC2796976 DOI: 10.1021/cb9000475] [Citation(s) in RCA: 70] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Normal growth and development depends upon high fidelity regulation of cap-dependent translation initiation, a process that is usurped and redirected in cancer to mediate acquisition of malignant properties. The epithelial-to-mesenchymal transition (EMT) is a key translationally regulated step in the development of epithelial cancers and pathological tissue fibrosis. To date, no compounds targeting EMT have been developed. Here we report the synthesis of a novel class of histidine triad nucleotide binding protein (HINT)-dependent pronucleotides that interdict EMT by negatively regulating the association of eIF4E with the mRNA cap. Compound eIF4E inhibitor-1 potently inhibited cap-dependent translation in a dose-dependent manner in zebrafish embryos without causing developmental abnormalities and prevented eIF4E from triggering EMT in zebrafish ectoderm explants without toxicity. Metabolism studies with whole cell lysates demonstrated that the prodrug was rapidly converted into 7-BnGMP. Thus we have successfully developed the first nontoxic small molecule able to inhibit EMT, a key process in the development of epithelial cancer and tissue fibrosis, by targeting the interaction of eIF4E with the mRNA cap and demonstrated the tractability of zebrafish as a model organism for studying agents that modulate EMT. Our work provides strong motivation for the continued development of compounds designed to normalize cap-dependent translation as novel chemo-preventive agents and therapeutics for cancer and fibrosis.
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Affiliation(s)
- Brahma Ghosh
- Department of Medicinal Chemistry, University of Minnesota, Minneapolis, MN 55455, USA
| | - Alexey O. Benyumov
- Department of Medicine, University of Minnesota, Minneapolis, MN 55455, USA
| | - Phalguni Ghosh
- Department of Medicinal Chemistry, University of Minnesota, Minneapolis, MN 55455, USA
| | - Yan Jia
- Department of Medicinal Chemistry, University of Minnesota, Minneapolis, MN 55455, USA
| | - Svetlana Avdulov
- Department of Medicine, University of Minnesota, Minneapolis, MN 55455, USA
| | - Peter S. Dahlberg
- Department of Medicine, University of Minnesota, Minneapolis, MN 55455, USA
| | - Mark Peterson
- Department of Medicine, University of Minnesota, Minneapolis, MN 55455, USA
| | - Karen Smith
- Department of Medicine, University of Minnesota, Minneapolis, MN 55455, USA
| | | | - Peter B. Bitterman
- Department of Medicine, University of Minnesota, Minneapolis, MN 55455, USA
| | - Carston R. Wagner
- Department of Medicinal Chemistry, University of Minnesota, Minneapolis, MN 55455, USA
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20
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Beaudoin ME, Poirel VJ, Krushel LA. Regulating amyloid precursor protein synthesis through an internal ribosomal entry site. Nucleic Acids Res 2008; 36:6835-47. [PMID: 18953033 PMCID: PMC2588504 DOI: 10.1093/nar/gkn792] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2008] [Revised: 09/14/2008] [Accepted: 10/10/2008] [Indexed: 12/31/2022] Open
Abstract
Expression of amyloid precursor protein (APP) is critical to the etiology of Alzheimer's disease (AD). Consequently, regulating APP expression is one approach to block disease progression. To this end, APP can be targeted at the levels of transcription, translation, and protein stability. Little is currently known about the translation of APP mRNA. Here, we report that endogenous APP mRNA is translated in neural cell lines via an internal ribosome entry site (IRES) located in the 5'-untranslated leader. The functional unit of the APP IRES is located within the 5' 50 nucleotides of the 5'-leader. In addition, we found that the APP IRES is positively regulated by two conditions correlated with AD, increased intracellular iron concentration and ischemia. Interestingly, the enhancement of APP IRES activity is dependent upon de novo transcription. Taken together, our data suggest that internal initiation of translation of the APP mRNA is an important mode for synthesis of APP, a mechanism which is regulated by conditions that also contribute to AD.
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Affiliation(s)
- Monique E. Beaudoin
- Neurosciences Program, Department of Biochemistry and Molecular Genetics and Department of Pharmacology, University of Colorado Denver School of Medicine, Aurora, CO 80045, USA
| | - Vincent-Joseph Poirel
- Neurosciences Program, Department of Biochemistry and Molecular Genetics and Department of Pharmacology, University of Colorado Denver School of Medicine, Aurora, CO 80045, USA
| | - Leslie A. Krushel
- Neurosciences Program, Department of Biochemistry and Molecular Genetics and Department of Pharmacology, University of Colorado Denver School of Medicine, Aurora, CO 80045, USA
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21
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Burgui I, Yángüez E, Sonenberg N, Nieto A. Influenza virus mRNA translation revisited: is the eIF4E cap-binding factor required for viral mRNA translation? J Virol 2007; 81:12427-38. [PMID: 17855553 PMCID: PMC2168979 DOI: 10.1128/jvi.01105-07] [Citation(s) in RCA: 69] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2007] [Accepted: 08/30/2007] [Indexed: 11/20/2022] Open
Abstract
Influenza virus mRNAs bear a short capped oligonucleotide sequence at their 5' ends derived from the host cell pre-mRNAs by a "cap-snatching" mechanism, followed immediately by a common viral sequence. At their 3' ends, they contain a poly(A) tail. Although cellular and viral mRNAs are structurally similar, influenza virus promotes the selective translation of its mRNAs despite the inhibition of host cell protein synthesis. The viral polymerase performs the cap snatching and binds selectively to the 5' common viral sequence. As viral mRNAs are recognized by their own cap-binding complex, we tested whether viral mRNA translation occurs without the contribution of the eIF4E protein, the cellular factor required for cap-dependent translation. Here, we show that influenza virus infection proceeds normally in different situations of functional impairment of the eIF4E factor. In addition, influenza virus polymerase binds to translation preinitiation complexes, and furthermore, under conditions of decreased eIF4GI association to cap structures, an increase in eIF4GI binding to these structures was found upon influenza virus infection. This is the first report providing evidence that influenza virus mRNA translation proceeds independently of a fully active translation initiation factor (eIF4E). The data reported are in agreement with a role of viral polymerase as a substitute for the eIF4E factor for viral mRNA translation.
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Affiliation(s)
- Idoia Burgui
- Centro Nacional de Biotecnología, CSIC Cantoblanco, 28049, Madrid, Spain
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22
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Piñeiro D, González VM, Hernández-Jiménez M, Salinas M, Martín ME. Translation regulation after taxol treatment in NIH3T3 cells involves the elongation factor (eEF)2. Exp Cell Res 2007; 313:3694-706. [PMID: 17825817 DOI: 10.1016/j.yexcr.2007.07.025] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2007] [Revised: 07/24/2007] [Accepted: 07/24/2007] [Indexed: 02/08/2023]
Abstract
Changes to the translational machinery that occur during apoptosis have been described in the last few years. The two principal ways in which translational factors are modified during apoptosis are: (i) changes in protein phosphorylation and (ii) specific proteolytic cleavages. Taxol, a member of a new class of anti-tubulin drugs, is currently used in chemotherapeutic treatments of different types of cancers. We have previously demonstrated that taxol induces calpain-mediated apoptosis in NIH3T3 cells [Piñeiro et al., Exp. Cell Res., 2007, 313:369-379]. In this study we found that translation was significantly inhibited during taxol-induced apoptosis in these cells. We have studied the phosphorylation status and expression levels of eIF2a, eIF4E, eIF4G and the regulatory protein 4E-BP1, all of which are implicated in translation regulation. We found that taxol treatment did not induce changes in eIF2alpha phosphorylation, but strongly decreased eIF4G, eIF4E and 4E-BP1 expression levels. MDL28170, a specific inhibitor of calpain, prevented reduction of eIF4G, but not of eIF4E or 4E-BP1 levels. Moreover, the calpain inhibitor did not block taxol-induced translation inhibition. All together these findings demonstrated that none of these factors are responsible for the taxol-induced protein synthesis inhibition. On the contrary, taxol treatment increased elongation factor eEF2 phosphorylation in a calpain-independent manner, supporting a role for eEF2 in taxol-induced translation inhibition.
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Affiliation(s)
- David Piñeiro
- Departamento de Bioquímica-Investigación, Hospital Ramón y Cajal, 28034 Madrid, Spain
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23
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Humphreys DT, Westman BJ, Martin DIK, Preiss T. MicroRNAs control translation initiation by inhibiting eukaryotic initiation factor 4E/cap and poly(A) tail function. Proc Natl Acad Sci U S A 2005; 102:16961-6. [PMID: 16287976 PMCID: PMC1287990 DOI: 10.1073/pnas.0506482102] [Citation(s) in RCA: 439] [Impact Index Per Article: 23.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
MicroRNAs (miRNAs) repress translation of target mRNAs by interaction with partially mismatched sequences in their 3' UTR. The mechanism by which they act on translation has remained largely obscure. We examined the translation of mRNAs containing four partially mismatched miRNA-binding sites in the 3' UTR in HeLa cells cotransfected with a cognate miRNA. The mRNAs were prepared by in vitro transcription and were engineered to employ different modes of translation initiation. We find that the 5' cap structure and the 3' poly(A) tail are each necessary but not sufficient for full miRNA-mediated repression of mRNA translation. Replacing the cap structure with an internal ribosome entry site from either the cricket paralysis virus or the encephalomyocarditis virus impairs miRNA-mediated repression. Collectively, these results demonstrate that miRNAs interfere with the initiation step of translation and implicate the cap-binding protein eukaryotic initiation factor 4E as a molecular target.
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Affiliation(s)
- David T Humphreys
- Molecular Genetics Program, Victor Chang Cardiac Research Institute (VCCRI), 384 Victoria Street, Darlinghurst (Sydney) NSW 2010, Australia
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Ghosh P, Park C, Peterson MS, Bitterman PB, Polunovsky VA, Wagner CR. Synthesis and evaluation of potential inhibitors of eIF4E cap binding to 7-methyl GTP. Bioorg Med Chem Lett 2005; 15:2177-80. [PMID: 15808492 DOI: 10.1016/j.bmcl.2005.01.080] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2004] [Revised: 01/25/2005] [Accepted: 01/27/2005] [Indexed: 11/30/2022]
Abstract
Cap-dependent translation is initiated by the binding of eIF4E to capped mRNA (m(7)GpppN). We have prepared a small library of 7-methyl guanosine nucleoside and nucleotide analogs and evaluated their ability to inhibit eIF4E binding to 7-methyl GTP with a competitive eIF4E binding immunoassay. 5'-H-Phosphonate derivatives in which the 2'- and 3'-riboside hydroxyls were tethered together by an isopropylidene group were shown to be a new class of inhibitors of eIF4E binding to capped mRNA.
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Affiliation(s)
- Phalguni Ghosh
- Department of Medicinal Chemistry, University of Minnesota, Minneapolis, MN 55455, USA
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25
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Salaün P, Boulben S, Mulner-Lorillon O, Bellé R, Sonenberg N, Morales J, Cormier P. Embryonic-stage-dependent changes in the level of eIF4E-binding proteins during early development of sea urchin embryos. J Cell Sci 2005; 118:1385-94. [PMID: 15769855 DOI: 10.1242/jcs.01716] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The eukaryotic initiation factor 4E (eIF4E)-binding proteins (4E-BPs) inhibit translation initiation by binding eIF4E and preventing recruitment of the translation machinery to mRNA. We have previously shown that fertilization of sea urchin eggs triggers eIF4E-4E-BP complex dissociation and 4E-BP degradation. Here, we show that microinjection of eIF4E-binding motif peptide into unfertilized eggs delays the onset of the first mitosis triggered by fertilization, demonstrating that dissociation of the eIF4E-4E-BP complex is functionally important for the first mitotic division in sea urchin embryos. We also show by gel filtration analyses that eIF4E is present in unfertilized eggs as an 80 kDa molecular mass complex containing 4E-BP and a new 4E-BP of 40 kDa. Fertilization triggers the dissociation of eIF4E from these two 4E-BPs and triggers the rapid recruitment of eIF4E into a high-molecular-mass complex. Release of eIF4E from the two 4E-BPs is correlated with a decrease in the total level of both 4E-BPs following fertilization. Abundance of the two 4E-BPs has been monitored during embryonic development. The level of the two proteins remains very low during the rapid cleavage stage of early development and increases 8 hours after fertilization. These results demonstrate that these two 4E-BPs are down- and upregulated during the embryonic development of sea urchins. Consequently, these data suggest that eIF4E availability to other partners represents an important determinant of the early development of sea urchin embryos.
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Affiliation(s)
- Patrick Salaün
- Station Biologique de Roscoff, Cycle Cellulaire et Développement, Unité Mer et Santé (UMR 7150), Université Pierre et Marie Curie (EI 37), Centre National de la Recherche Scientifique (CNRS), BP 74, 29682 Roscoff Cedex, France
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26
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Abstract
Eukaryotic messenger RNAs contain a modified guanosine, termed a cap, at their 5' ends. Translation of mRNAs requires the binding of an initiation factor, eIF4E, to the cap structure. Here, we describe a family of proteins that through a shared sequence regulate cap-dependent translation. The biological importance of this translational regulation is immense, and affects such processes as cell growth, development, oncogenic transformation and perhaps even axon pathfinding and memory consolidation.
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Affiliation(s)
- Joel D Richter
- Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, Massachusetts 01605, USA.
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Topisirovic I, Ruiz-Gutierrez M, Borden KLB. Phosphorylation of the eukaryotic translation initiation factor eIF4E contributes to its transformation and mRNA transport activities. Cancer Res 2005; 64:8639-42. [PMID: 15574771 DOI: 10.1158/0008-5472.can-04-2677] [Citation(s) in RCA: 201] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The eukaryotic translation initiation factor eIF4E is dysregulated in a wide variety of human cancers. In the cytoplasm, eIF4E acts in the rate-limiting step of translation initiation whereas in the nucleus, eIF4E forms nuclear bodies and promotes the nucleo-cytoplasmic export of a subset of growth-promoting mRNAs including cyclin D1. The only known post-translational modification of eIF4E is its phosphorylation at S209. Many studies have examined the role of phosphorylation on cap-dependent translation. However, no studies to date have explored the role of phosphorylation on the ability of eIF4E to transform cells. Using mutagenesis and separately a small molecular inhibitor of eIF4E phosphorylation, we show that eIF4E phosphorylation enhances both its mRNA transport function and its transformation activity in cell culture. Thus, phosphorylation of nuclear eIF4E seems to be an important step in control of the mRNA transport and thus the transforming properties of eIF4E.
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Affiliation(s)
- Ivan Topisirovic
- Structural Biology Program, Department of Physiology and Biophysics, Mount Sinai School of Medicine, New York University, New York, New York, USA
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Zuberek J, Jemielity J, Jablonowska A, Stepinski J, Dadlez M, Stolarski R, Darzynkiewicz E. Influence of electric charge variation at residues 209 and 159 on the interaction of eIF4E with the mRNA 5' terminus. Biochemistry 2004; 43:5370-9. [PMID: 15122903 DOI: 10.1021/bi030266t] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Eukaryotic translation initiation factor 4E (eIF4E) is essential for efficient protein synthesis in cap-dependent translation. The protein specifically binds the cap structure at the mRNA 5' terminus and facilitates the assembly of the mRNA with other initiation factors and the 40S ribosomal subunit. Phosphorylation of eIF4E is implicated in the regulation of the initiation step of translation. However, the molecular mechanism of this regulation still remains unclear. To address this problem, we have determined the binding affinities of eIF4E specifically mutated at position 209 or 159 for a series of novel mono- and dinucleotide cap analogues by a fluorometric time-synchronized titration method. A 1.5-3-fold reduction in the affinity of cap for the S209E mutant and a 1-2-fold increase in the affinity of cap for the S209K mutant, depending on the negative charge of phosphate chains, indicate that phosphorylation at Ser209 creates electrostatic repulsion between the protein and the negatively charged cap structure. The inhibition of the ability to bind cap analogues by the K159A mutant and its phosphorylated counterpart shows significant participation of Lys159 in the binding of the capped mRNA. Both structural modifications, phosphorylation and the replacement of lysine with alanine, result in an increase in the negative Gibbs free energy of association that is proportional to the length of the cap phosphate chain and additive, i.e., equal to the sum of the individual destabilizing changes of DeltaG degrees. The possible implication of these results for the mechanism of control of eIF4E by phosphorylation, especially for the "clamping model", is discussed.
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Affiliation(s)
- Joanna Zuberek
- Department of Biophysics, Institute of Experimental Physics, Warsaw University, 93 Zwirki i Wigury Street, 02-089 Warsaw, Poland
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Abstract
The contribution of the mRNA cap-binding protein, eIF-4E, to malignant transformation and progression has been illuminated over the past decade. eIF-4E overexpression has been demonstrated in human tumors of the breast, head and neck, colon, prostate, bladder, cervix and lung, and has been related to disease progression. Overexpression of eIF-4E in experimental models dramatically alters cellular morphology, enhances proliferation and induces cellular transformation, tumorigenesis and metastasis. Conversely, blocking eIF-4E function by expression of antisense RNA, or overexpression of the inhibitory eIF-4E binding proteins (4E-BPs), suppresses cellular transformation, tumor growth, tumor invasiveness and metastasis. Although eIF-4E regulates the recruitment of mRNA to ribosomes, and thereby globally regulates cap-dependent protein synthesis, eIF-4E contributes to malignancy by selectively enabling the translation of a limited pool of mRNAs--those that generally encode key proteins involved in cellular growth, angiogenesis, survival and malignancy (e.g. cyclin D1, c-myc, vascular endothelial growth factor, matrix metalloprotease 9). A deeper understanding of the role of eIF-4E in regulating the translation of the diverse gene products involved in all aspects of malignancy will improve the capacity to exploit eIF-4E as a therapeutic target and as a marker for human cancer progression.
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Affiliation(s)
- Arrigo De Benedetti
- Department of Biochemistry and Molecular Biology, Louisiana State University Medical Center, Shreveport, 1501 Kings Highway, PO Box 33932, Shreveport, LA 71130, USA.
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Nimmanapalli R, Bali P, O'Bryan E, Fuino L, Guo F, Wu J, Houghton P, Bhalla K. Arsenic trioxide inhibits translation of mRNA of bcr-abl, resulting in attenuation of Bcr-Abl levels and apoptosis of human leukemia cells. Cancer Res 2003; 63:7950-8. [PMID: 14633726] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/27/2023]
Abstract
Present studies demonstrate that treatment with arsenic trioxide (AT) lowered ectopically expressed or endogenous levels of Bcr-Abl protein, as well as induced apoptosis of Bcr-Abl-expressing cultured and primary chronic myeloid leukemia cells, including those refractory to imatinib mesylate. Treatment with AT neither affected bcr-abl mRNA transcript levels nor promoted the proteasomal degradation of Bcr-Abl. Importantly, in [(35)S]methionine-labeled leukemia cells, exposure to AT rapidly lowered the levels of the newly synthesized Bcr-Abl, indicating inhibition of bcr-abl mRNA translation. Treatment with AT rapidly inhibited the activity of 3-phosphoinositide-dependent protein kinase-1, as well as of p70 S6 kinase-1. p70 S6 kinase-1 is known to be a positive regulator of the translation of a group of mRNAs that possesses a long and highly structured 5'-untranslated region (UTR) containing a tract of oligopyrimidines (TOP). Because bcr-abl mRNA was discovered to possess a long and highly structured 5'-UTR containing a 12-pyrimidine TOP sequence in its 5'-UTR, we determined the effect of AT in Jurkat cells with ectopic expression of a 5'-UTR-deleted mutant of the bcr-abl gene, i.e., Jurkat/Bcr-Abl (5'UTR-) cells. Treatment with AT neither lowered the levels of the 5'-UTR-deleted mutant of Bcr-Abl nor induced apoptosis of Jurkat/Bcr-Abl (5'UTR-) cells. Taken together, these findings demonstrate a novel mechanism by which AT down-regulates Bcr-Abl levels and induces apoptosis of Bcr-Abl-positive chronic myelogenous leukemia cells.
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MESH Headings
- 3-Phosphoinositide-Dependent Protein Kinases
- 5' Untranslated Regions
- Apoptosis/drug effects
- Apoptosis/genetics
- Arsenic Trioxide
- Arsenicals/pharmacology
- Down-Regulation/drug effects
- Eukaryotic Initiation Factor-4E/antagonists & inhibitors
- Eukaryotic Initiation Factor-4E/metabolism
- Fusion Proteins, bcr-abl/antagonists & inhibitors
- Fusion Proteins, bcr-abl/biosynthesis
- Fusion Proteins, bcr-abl/genetics
- Genes, abl/drug effects
- Genes, abl/genetics
- HL-60 Cells
- Humans
- Jurkat Cells
- Leukemia, Myelogenous, Chronic, BCR-ABL Positive/genetics
- Leukemia, Myelogenous, Chronic, BCR-ABL Positive/metabolism
- Oxides/pharmacology
- Protein Biosynthesis/drug effects
- Protein Serine-Threonine Kinases/antagonists & inhibitors
- Protein Serine-Threonine Kinases/metabolism
- RNA, Messenger/antagonists & inhibitors
- RNA, Messenger/genetics
- RNA, Messenger/metabolism
- Ribosomal Protein S6 Kinases, 70-kDa/antagonists & inhibitors
- Ribosomal Protein S6 Kinases, 70-kDa/metabolism
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Affiliation(s)
- Ramadevi Nimmanapalli
- Interdisciplinary Oncology Program, Moffitt Cancer Center and Research Institute, University of South Florida, 12902 Magnolia Drive, Tampa, FL 33612, USA
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Yang YJ, Zhang YL, Lai ZS, Wang JD, Wu BP, Wang YD. [Contribution of eukaryotic initiation factor-4E inhibition to heparanase expression and activity in human colon adenocarcinoma cell line LS-174T]. Zhonghua Zhong Liu Za Zhi 2003; 25:542-5. [PMID: 14690557] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 04/27/2023]
Abstract
OBJECTIVE To determine whether the eukaryotic initiation factor-4E (eIF-4E) is involved in the cap-dependent translational regulation of heparanase and study the correlation between heparanase expression and metastatic potential of LS-174T cells. METHODS The protein and mRNA levels of inhibited eIF-4E were tested by Western blot and RT-PCR. Heparanase activity was defined as the ability to degrade high molecular weight (40-100 000) radiolabeled ((35)S) heparan sulfate (HS) substrate into low molecular weight (5-15 000) HS fragments. The invasive potential of tumor cells in vitro was observed by Matrigel invasion assay system. RESULTS The 20-mer antisense oligonucleotide (asODN) against eIF-4E specifically and significantly inhibited eIF-4E expression at both transcriptional and translational levels. The expression and the activity of heparanase were effectively lowered, which further decreased the invasive potential of LS-174T. CONCLUSION eIF-4E, probably being involved in translational regulation of heparanase in colon adenocarcinoma cell line LS-174T, can be a particularly interesting target for heparanase regulation, based on of its critical function.
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Affiliation(s)
- Yu-jie Yang
- Institute of Digestive Diseases, Nanfang Hospital, First Military Medical University, Guangzhou 510515, China
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Yang YJ, Zhang YL, Li X, Dan HL, Lai ZS, Wang JD, Wang QY, Cui HH, Sun Y, Wang YD. Contribution of eIF-4E inhibition to the expression and activity of heparanase in human colon adenocarcinoma cell line: LS-174T. World J Gastroenterol 2003; 9:1707-12. [PMID: 12918105 PMCID: PMC4611528 DOI: 10.3748/wjg.v9.i8.1707] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
AIM: Heparanase degrades heparan sulfate proteoglycans (HSPGs) and is a critical mediator of tumor metastasis and angiogenesis. Recently, it has been cloned as a single gene family and found to be a potential target for antimetastasis drugs. However, the molecular basis for the regulation of heparanase expression is still not quite clear. The aim of this study was to determine whether the expression of eukaryotic initiation factor 4E (eIF-4E) correlated with the heparanase level in tumor cells and to explore the correlation between heparanase expression and metastatic potential of LS-174T cells.
METHODS: A 20-mer antisense s-oligodeoxynucleotide (asODN) targeted against the translation start site of eIF-4E mRNA was introduced into LS-174T cells by lipid-mediated DNA-transfection. eIF-4E protein and mRNA levels were detected by Western blot analysis and RT-PCR, respectively. Heparanase activity was defined as the ability to degrade high molecular weight (40-100 kDa) radiolabeled HS (heparan sulfate) substrate into low molecular weight (5-15 kDa) HS fragments that could be differentiated by gel filtration chromatography. The invasive potential of tumor cell in vitro was observed by using a Matrigel invasion assay system.
RESULTS: The 20-mer asODN against eIF-4E specifically and significantly inhibited eIF-4E expression at both transcriptional and translational levels. As a result, the expression and activity of heparanase were effectively retarded and the decreased activity of heparanase resulted in the decreased invasive potential of LS-174T.
CONCLUSION: eIF-4E is involved in the regulation of heparanase production in colon adenocarcinoma cell line LS-174T, and its critical function makes it a particularly interesting target for heparanase regulation. This targeting strategy in antisense chemistry may have practical applications in experimental or clinical anti-metastatic gene therapy of human colorectal carcinoma.
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Affiliation(s)
- Yu-Jie Yang
- Chinese PLA Institute of Digestive Disease, Nanfang Hospital, First Military Medical University, Guangzhou 510515, Guangdong Province, China.
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Yang YJ, Zhang YL, Lai ZS, Cui HH, Zhong SS, Liu YH. Effect of eIF-4E inhibition on heparanase mRNA and its expression in colon adenocarcinoma cell. Di Yi Jun Yi Da Xue Xue Bao 2003; 23:655-8. [PMID: 12865212] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 03/03/2023]
Abstract
OBJECTIVE To verify whether inhibition of the overexpressed eukaryotic initiation factor-4E (eIF-4E) in human colon adenocarcinoma cell line LS-174T may facilitate the degradation of heparanase mRNA and alter the translation and expression levels of heparanase protein. METHODS A 20-mer antisense s-oligodeoxynucleotide (asODN) targeted against the translation start site of eIF-4E mRNA was introduced into LS-174T cells by means of lipid-mediated DNA-transfection, followed by Western blotting analysis and reverse transcription-PCR to determine eIF-4E protein and mRNA levels, respectively. Northern methods was applied to determine heparanase mRNA expression level, with the alterations of heparanase expression assessed by Western blotting analysis. RESULTS The 20-mer asODN against eIF-4E specifically and significantly inhibited eIF-4E protein expression, and as a result, a significant reduction in heparanase mRNA level was observed by Northern blotting in conjunction with significantly decreased heparanase protein expression. CONCLUSION The inhibition of eIF-4E strongly reduces the stability of heparanase mRNA in colon adenocarcinoma cell line LS-174T and results in an apparent reduction in the expression of heparanase protein.
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Affiliation(s)
- Yu-jie Yang
- Institute of Digestive Diseases of PLA, Nanfang Hospital, First Military Medical University, Guangzhou 510515, China.
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Topisirovic I, Culjkovic B, Cohen N, Perez JM, Skrabanek L, Borden KL. The proline-rich homeodomain protein, PRH, is a tissue-specific inhibitor of eIF4E-dependent cyclin D1 mRNA transport and growth. EMBO J 2003; 22:689-703. [PMID: 12554669 PMCID: PMC140753 DOI: 10.1093/emboj/cdg069] [Citation(s) in RCA: 129] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The translation initiation factor eIF4E is involved in the modulation of cellular growth. In the nucleus, where eIF4E is associated with PML nuclear bodies, eIF4E mediates nucleocytoplasmic transport of specific transcripts, and this contributes to its transformation activity. Surprisingly, we found that a trans cription factor, the proline-rich homeodomain protein PRH, is a negative regulator of eIF4E in myeloid cells, interacting with eIF4E through a conserved binding site typically found in translational regulators. Through this interaction, PRH inhibits eIF4E-dependent mRNA transport and subsequent transformation. These activities of PRH are independent of its transcriptional functions. Further, we found that 199 homeodomain proteins contain potential eIF4E-binding sites. Thus, there could be many tissue-specific regulators of eIF4E. These findings provide a model for regulation of a general factor, eIF4E, in tissue- specific contexts, and suggest that its regulation is important in differentiation and development.
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Affiliation(s)
| | | | | | | | - Lucy Skrabanek
- Structural Biology Program and
Institute for Computational Biomedicine, Department of Physiology and Biophysics, Mount Sinai School of Medicine, New York University, One Gustave Levy Place, New York, NY 10029, USA Corresponding author e-mail:
| | - Katherine L.B. Borden
- Structural Biology Program and
Institute for Computational Biomedicine, Department of Physiology and Biophysics, Mount Sinai School of Medicine, New York University, One Gustave Levy Place, New York, NY 10029, USA Corresponding author e-mail:
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