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Grove DJ, Russell PJ, Kearse MG. To initiate or not to initiate: A critical assessment of eIF2A, eIF2D, and MCT-1·DENR to deliver initiator tRNA to ribosomes. WILEY INTERDISCIPLINARY REVIEWS. RNA 2024; 15:e1833. [PMID: 38433101 PMCID: PMC11260288 DOI: 10.1002/wrna.1833] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/31/2023] [Revised: 01/15/2024] [Accepted: 01/17/2024] [Indexed: 03/05/2024]
Abstract
Selection of the correct start codon is critical for high-fidelity protein synthesis. In eukaryotes, this is typically governed by a multitude of initiation factors (eIFs), including eIF2·GTP that directly delivers the initiator tRNA (Met-tRNAi Met ) to the P site of the ribosome. However, numerous reports, some dating back to the early 1970s, have described other initiation factors having high affinity for the initiator tRNA and the ability of delivering it to the ribosome, which has provided a foundation for further work demonstrating non-canonical initiation mechanisms using alternative initiation factors. Here we provide a critical analysis of current understanding of eIF2A, eIF2D, and the MCT-1·DENR dimer, the evidence surrounding their ability to initiate translation, their implications in human disease, and lay out important key questions for the field. This article is categorized under: RNA Interactions with Proteins and Other Molecules > RNA-Protein Complexes Translation > Mechanisms Translation > Regulation.
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Affiliation(s)
- Daisy J. Grove
- The Ohio State Biochemistry Program, Department of Biological Chemistry, Center for RNA Biology, The Ohio State University, Columbus, Ohio, USA
| | - Paul J. Russell
- The Ohio State Biochemistry Program, Department of Biological Chemistry, Center for RNA Biology, The Ohio State University, Columbus, Ohio, USA
- The Cellular, Molecular, Biochemical Sciences Program, Department of Biological Chemistry, Center for RNA Biology, The Ohio State University, Columbus, Ohio, USA
| | - Michael G. Kearse
- The Ohio State Biochemistry Program, Department of Biological Chemistry, Center for RNA Biology, The Ohio State University, Columbus, Ohio, USA
- The Cellular, Molecular, Biochemical Sciences Program, Department of Biological Chemistry, Center for RNA Biology, The Ohio State University, Columbus, Ohio, USA
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2
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Deng M, Xiong C, He ZK, Bin Q, Song JZ, Li W, Qin J. MCTS1 as a Novel Prognostic Biomarker and Its Correlation With Immune Infiltrates in Breast Cancer. Front Genet 2022; 13:825901. [PMID: 35295953 PMCID: PMC8918534 DOI: 10.3389/fgene.2022.825901] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2021] [Accepted: 02/04/2022] [Indexed: 01/22/2023] Open
Abstract
Multiple copies in T‐cell lymphoma‐1 (MCTS1) plays an important role in various cancers; however, its effects on patient prognosis and immune infiltration in breast cancer remain unclear. In this study, the expression profiles and clinical information of patients with breast cancer were obtained from the Cancer Genome Atlas (TCGA) database. Using the Wilcoxon rank-sum test, the MCTS1 expression levels were compared between breast cancer and normal breast tissues. Functional enrichment analyses were performed to explore the potential signaling pathways and biological functions that are involved. Immune cell infiltration was assessed using single-sample gene set enrichment analysis. The UALCAN and MethSurv databases were used to analyze the methylation status of the MCTS1. The Kaplan-Meier method and Cox regression analysis were used to identify the prognostic value of MCTS1. A nomogram was constructed to predict the overall survival (OS) rates at one-, three-, and five-years post-cancer diagnosis. MCTS1 was overexpressed in breast cancer and significantly associated with the M pathological stage, histological type, PAM50, and increased age. MCTS1 overexpression contributes to a significant decline in OS and disease-specific survival. Multivariate Cox analysis identified MCTS1 as an independent negative prognostic marker of OS. The OS nomogram was generated with a concordance index of 0.715. Similarly, the hypomethylation status of MCTS1 is also associated with poor prognosis. Functional enrichment analysis indicated that the enriched pathways included the reactive oxygen species signaling pathway, MYC targets, interferon alpha response, immune response regulating signaling pathway, and leukocyte migration. Moreover, the overexpression of MCTS1 was negatively correlated with the levels of immune cell infiltration of natural killer cells, CD8+ T cells, effector memory T cells, and plasmacytoid dendritic cells. Therefore, MCTS1 maybe a novel prognostic biomarker.
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Affiliation(s)
- Mei Deng
- Department of Radiation Oncology, Affiliated Hospital of Guilin Medical University, Guilin, China
- *Correspondence: Mei Deng,
| | - Chao Xiong
- Department of Information, Affiliated Hospital of Guilin Medical University, Guilin, China
| | - Zhuo-Kai He
- Department of Radiation Oncology, Affiliated Hospital of Guilin Medical University, Guilin, China
| | - Qiong Bin
- Department of Radiation Oncology, Affiliated Hospital of Guilin Medical University, Guilin, China
| | - Jing-Zhi Song
- Department of Radiation Oncology, Affiliated Hospital of Guilin Medical University, Guilin, China
| | - Wei Li
- Department of Radiation Oncology, Affiliated Hospital of Guilin Medical University, Guilin, China
| | - Jie Qin
- Department of Nuclear Medicine, Affiliated Hospital of Guilin Medical University, Guilin, China
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Clemm von Hohenberg K, Müller S, Schleich S, Meister M, Bohlen J, Hofmann TG, Teleman AA. Cyclin B/CDK1 and Cyclin A/CDK2 phosphorylate DENR to promote mitotic protein translation and faithful cell division. Nat Commun 2022; 13:668. [PMID: 35115540 PMCID: PMC8813921 DOI: 10.1038/s41467-022-28265-0] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2021] [Accepted: 01/12/2022] [Indexed: 12/11/2022] Open
Abstract
DENR and MCTS1 have been identified as oncogenes in several different tumor entities. The heterodimeric DENR·MCTS1 protein complex promotes translation of mRNAs containing upstream Open Reading Frames (uORFs). We show here that DENR is phosphorylated on Serine 73 by Cyclin B/CDK1 and Cyclin A/CDK2 at the onset of mitosis, and then dephosphorylated as cells exit mitosis. Phosphorylation of Ser73 promotes mitotic stability of DENR protein and prevents its cleavage at Asp26. This leads to enhanced translation of mRNAs involved in mitosis. Indeed, we find that roughly 40% of all mRNAs with elevated translation in mitosis are DENR targets. In the absence of DENR or of Ser73 phosphorylation, cells display elevated levels of aberrant mitoses and cell death. This provides a mechanism how the cell cycle regulates translation of a subset of mitotically relevant mRNAs during mitosis. The cell cycle regulates translation during mitosis by controlling DENR stability. Here, the authors show the non-canonical translation initiation complex DENR·MCTS1 is phosphorylated during mitosis by CDK1 and 2, enabling the translation of genes needed for proper mitotic progression.
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Affiliation(s)
- Katharina Clemm von Hohenberg
- German Cancer Research Center (DKFZ), 69120, Heidelberg, Germany.,Heidelberg University, 69120, Heidelberg, Germany.,CellNetworks-Cluster of Excellence, Heidelberg University, Heidelberg, Germany.,Department of Medicine III, Universitätsmedizin Mannheim, 68167, Mannheim, Germany
| | - Sandra Müller
- German Cancer Research Center (DKFZ), 69120, Heidelberg, Germany.,Heidelberg University, 69120, Heidelberg, Germany
| | - Sibylle Schleich
- German Cancer Research Center (DKFZ), 69120, Heidelberg, Germany.,Heidelberg University, 69120, Heidelberg, Germany
| | - Matthias Meister
- Division of Viral Transformation Mechanisms, German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Jonathan Bohlen
- German Cancer Research Center (DKFZ), 69120, Heidelberg, Germany.,Heidelberg University, 69120, Heidelberg, Germany.,CellNetworks-Cluster of Excellence, Heidelberg University, Heidelberg, Germany.,Laboratory of Human Genetics of Infectious Diseases, Necker Branch, INSERM U1163, Paris, France.,University of Paris, Imagine Institute, Paris, France
| | - Thomas G Hofmann
- Institute of Toxicology, University Medical Center Mainz at the Johannes Gutenberg University of Mainz, Mainz, Germany
| | - Aurelio A Teleman
- German Cancer Research Center (DKFZ), 69120, Heidelberg, Germany. .,Heidelberg University, 69120, Heidelberg, Germany. .,CellNetworks-Cluster of Excellence, Heidelberg University, Heidelberg, Germany.
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4
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Huang Z, Su Q, Li W, Ren H, Huang H, Wang A. MCTS1 promotes invasion and metastasis of oral cancer by modifying the EMT process. ANNALS OF TRANSLATIONAL MEDICINE 2021; 9:997. [PMID: 34277797 PMCID: PMC8267330 DOI: 10.21037/atm-21-2361] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/01/2021] [Accepted: 05/28/2021] [Indexed: 12/12/2022]
Abstract
Background The oncogene, malignant T-cell-amplified sequence 1 (MCTS1), has been found to be highly expressed in a variety of cancer cell lines. It has been shown to be involved in cell cycle progression and to confer a growth advantage for lymphomas and breast cancer. Nevertheless, the role of MCTS1 in contributing to the development of oral cancer remains elusive. Methods We analyzed the gene expression profiles of MCTS1 in normal oral keratinocytes and cancerous cells. Cellular proliferation, invasion, and migration experiments were performed to detect the effect of MCTS1 on the biological evolution of oral cancer. The in vitro results were verified by the in vivo lymphatic metastasis test. The underlying mechanism of MCTS1 in promoting oral cancer invasion and metastasis correlated with the epithelial-mesenchymal transition (EMT) process as revealed by western blotting. Results The results showed that MCTS1 was aberrantly expressed in oral cancer cells. MCTS1 overexpression significantly promoted tumor cell growth, proliferation, migration, and invasion. MCTS1-mediated lymphatic metastasis was verified in vivo using an intraplantar tumor model. Biomarkers associated with EMT progression were positively or negatively regulated upon knockdown or overexpression of MCTS1, respectively. Conclusions Higher MCTS1 expression in oral cancer may be connected with an unfavorable prognosis due to involvement of MCTS1. MCTS1 potentiates the growth and proliferation of oral cancer cells and subsequent metastasis by regulating cell cycle and modifying the EMT process. Keywords Oral cancer; oncogene; malignant T-cell-amplified sequence 1 (MCTS1); metastasis; invasion.
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Affiliation(s)
- Zhexun Huang
- Department of Oral and Maxillofacial Surgery, the First Affiliated Hospital, Sun Yat-sen University, Guangzhou, China
| | - Qiao Su
- Animal Experiment Center, the First Affiliated Hospital, Sun Yat-sen University, Guangzhou, China
| | - Wuguo Li
- Animal Experiment Center, the First Affiliated Hospital, Sun Yat-sen University, Guangzhou, China
| | - Hui Ren
- Department of Oral and Maxillofacial Surgery, the First Affiliated Hospital, Sun Yat-sen University, Guangzhou, China
| | - Huiqiang Huang
- Department of Medical Oncology, Sun Yat-sen University Cancer Center, Guangzhou, China.,State Key Laboratory of Oncology in South China, Guangzhou, China; Collaborative Innovation Center for Cancer Medicine, Guangzhou, China
| | - Anxun Wang
- Department of Oral and Maxillofacial Surgery, the First Affiliated Hospital, Sun Yat-sen University, Guangzhou, China
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The oncogene Mct-1 promotes progression of hepatocellular carcinoma via enhancement of Yap-mediated cell proliferation. Cell Death Discov 2021; 7:57. [PMID: 33753742 PMCID: PMC7985373 DOI: 10.1038/s41420-021-00413-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2020] [Revised: 12/22/2020] [Accepted: 01/15/2021] [Indexed: 12/24/2022] Open
Abstract
Malignant T-cell-amplified sequence 1 (Mct-1) has been reported as an oncogene in multiple malignant diseases. However, the function of Mct-1 in hepatocellular carcinoma (HCC) and the molecular mechanisms underlying tumor progression have not been explored. In this study, Mct-1 expression levels in HCC tissues and cells were detected by quantitative real-time PCR and western blotting. Mct-1 shRNAs and overexpression vector were transfected into HCC cells to downregulate or upregulate Mct-1 expression. In vitro and in vivo assays were performed to investigate the function of Mct-1 in cell proliferation and apoptosis. RNA sequencing analysis (RNA-seq) was performed to explore differences in gene expression when silenced Mct-1 expression. Mct-1 was upregulated in HCC specimens and cell lines, and higher expression of Mct-1 was predictive of poor survival. Overexpression of Mct-1 was shown to promote cell proliferation and repress cell apoptosis both in vitro and in vivo. The results of RNA-seq indicated that knockdown of Mct-1 suppressed Yap expression, while the results of the luciferase assay also revealed that Mct-1 increases the activity of the Yap promoter. Restoration of Yap expression in Mct-1 knockdown cells partially recovered the promotion of cell proliferation and inhibition of apoptosis. Collectively, these results indicate that Mct-1 acts as a tumor promoter gene in HCC progression by up-regulating Yap expression and, thus, could serve a novel potential diagnostic and prognostic biomarker for HCC.
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Lomakin IB, Stolboushkina EA, Vaidya AT, Zhao C, Garber MB, Dmitriev SE, Steitz TA. Crystal Structure of the Human Ribosome in Complex with DENR-MCT-1. Cell Rep 2018; 20:521-528. [PMID: 28723557 DOI: 10.1016/j.celrep.2017.06.025] [Citation(s) in RCA: 44] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2017] [Revised: 05/12/2017] [Accepted: 06/07/2017] [Indexed: 12/24/2022] Open
Abstract
The repertoire of the density-regulated protein (DENR) and the malignant T cell-amplified sequence 1 (MCT-1/MCTS1) oncoprotein was recently expanded to include translational control of a specific set of cancer-related mRNAs. DENR and MCT-1 form the heterodimer, which binds to the ribosome and operates at both translation initiation and reinitiation steps, though by a mechanism that is yet unclear. Here, we determined the crystal structure of the human small ribosomal subunit in complex with DENR-MCT-1. The structure reveals the location of the DENR-MCT-1 dimer bound to the small ribosomal subunit. The binding site of the C-terminal domain of DENR on the ribosome has a striking similarity with those of canonical initiation factor 1 (eIF1), which controls the fidelity of translation initiation and scanning. Our findings elucidate how the DENR-MCT-1 dimer interacts with the ribosome and have functional implications for the mechanism of unconventional translation initiation and reinitiation.
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Affiliation(s)
- Ivan B Lomakin
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06520-8114, USA.
| | - Elena A Stolboushkina
- Institute of Protein Research, Russian Academy of Sciences, Pushchino, Moscow Region 142290, Russia; Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, Moscow 119991, Russia
| | - Anand T Vaidya
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06520-8114, USA
| | - Chenguang Zhao
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06520-8114, USA
| | - Maria B Garber
- Institute of Protein Research, Russian Academy of Sciences, Pushchino, Moscow Region 142290, Russia
| | - Sergey E Dmitriev
- Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, Moscow 119991, Russia; Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow 119234, Russia
| | - Thomas A Steitz
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06520-8114, USA; Howard Hughes Medical Institute, Yale University, New Haven, CT 06520-8114, USA.
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7
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Weisser M, Schäfer T, Leibundgut M, Böhringer D, Aylett CHS, Ban N. Structural and Functional Insights into Human Re-initiation Complexes. Mol Cell 2017; 67:447-456.e7. [PMID: 28732596 DOI: 10.1016/j.molcel.2017.06.032] [Citation(s) in RCA: 53] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2017] [Revised: 06/14/2017] [Accepted: 06/27/2017] [Indexed: 02/05/2023]
Abstract
After having translated short upstream open reading frames, ribosomes can re-initiate translation on the same mRNA. This process, referred to as re-initiation, controls the translation of a large fraction of mammalian cellular mRNAs, many of which are important in cancer. Key ribosomal binding proteins involved in re-initiation are the eukaryotic translation initiation factor 2D (eIF2D) or the homologous complex of MCT-1/DENR. We determined the structures of these factors bound to the human 40S ribosomal subunit in complex with initiator tRNA positioned on an mRNA start codon in the P-site using a combination of cryoelectron microscopy and X-ray crystallography. The structures, supported by biochemical experiments, reveal how eIF2D emulates the function of several canonical translation initiation factors by using three independent, flexibly connected RNA binding domains to simultaneously monitor codon-anticodon interactions in the ribosomal P-site and position the initiator tRNA.
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Affiliation(s)
- Melanie Weisser
- Department of Biology, Institute of Molecular Biology and Biophysics, Otto-Stern-Weg 5, ETH Zurich, CH-8093 Zurich, Switzerland
| | - Tanja Schäfer
- Department of Biology, Institute of Molecular Biology and Biophysics, Otto-Stern-Weg 5, ETH Zurich, CH-8093 Zurich, Switzerland
| | - Marc Leibundgut
- Department of Biology, Institute of Molecular Biology and Biophysics, Otto-Stern-Weg 5, ETH Zurich, CH-8093 Zurich, Switzerland
| | - Daniel Böhringer
- Department of Biology, Institute of Molecular Biology and Biophysics, Otto-Stern-Weg 5, ETH Zurich, CH-8093 Zurich, Switzerland
| | | | - Nenad Ban
- Department of Biology, Institute of Molecular Biology and Biophysics, Otto-Stern-Weg 5, ETH Zurich, CH-8093 Zurich, Switzerland.
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8
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Li Y, Zhao Y, Zhou X, Ni W, Dai Z, Yang D, Hao J, Luo L, Liu Y, Luo X, Zhao X. Cytotoxic Indole Alkaloid 3α-Acetonyltabersonine Induces Glioblastoma Apoptosis via Inhibition of DNA Damage Repair. Toxins (Basel) 2017; 9:toxins9050150. [PMID: 28452946 PMCID: PMC5450698 DOI: 10.3390/toxins9050150] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2017] [Revised: 04/16/2017] [Accepted: 04/19/2017] [Indexed: 01/17/2023] Open
Abstract
Cytotoxic indole alkaloids from Melodinus suaveolens, which belongs to the toxic plant family Apocynaceae, demonstrated impressive antitumor activities in many tumor types, but less application in glioblastoma, which is the lethal brain tumor. In the present study, we reported the anti-glioblastoma activity of an indole alkaloid, 3α-acetonyltabersonine, which was isolated from Melodinus suaveolens. 3α-acetonyltabersonine was cytotoxic to glioblastoma cell lines (U87 and T98G) and stem cells at low concentrations. We verified 3α-acetonyltabersonine could suppress tumor cell proliferation and cause apoptosis in glioblastoma stem cells (GSCs). Moreover, detailed investigation of transcriptome study and Western blotting analysis indicated the mitogen activated protein kinase (MAPK) pathway was activated by phosphorylation upon 3α-acetonyltabersonine treatment. Additionally, we found 3α-acetonyltabersonine inhibited DNA damage repair procedures, the accumulated DNA damage stimulated activation of MAPK pathway and, finally, induced apoptosis. Further evidence was consistently obtained from vivo experiments on glioblastoma mouse model: treatment of 3α-acetonyltabersonine could exert pro-apoptotic function and prolong the life span of tumor-bearing mice. These results in vitro and in vivo suggested that 3α-acetonyltabersonine could be a potential candidate antitumor agent.
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Affiliation(s)
- Yuan Li
- Key Laboratory of Animal Models and Human Disease Mechanisms of Chinese Academy of Sciences and Yunnan Province, Kunming Institute of Zoology, Chinese Academy of Sciences, 21 Qingsong Road, Kunming 650203, China.
- Kunming College of Life Science, University of Chinese Academy of Sciences, 19 Qingsong Road, Kunming 650203, China.
- Graduate School, University of Chinese Academy of Sciences, 19 Yuquan Road, Beijing 100049, China.
- Division of Science and Technology, Kunming University of Science and Technology, 727 South Jingming Road, Kunming 650500, China.
| | - Yunli Zhao
- State Key Laboratory of Phytochemistry and Plant Resources in West China, Kunming Institute of Botany, Chinese Academy of Sciences, 132 Lanhei Road, Kunming 650201, China.
| | - Xia Zhou
- Key Laboratory of Animal Models and Human Disease Mechanisms of Chinese Academy of Sciences and Yunnan Province, Kunming Institute of Zoology, Chinese Academy of Sciences, 21 Qingsong Road, Kunming 650203, China.
- Kunming College of Life Science, University of Chinese Academy of Sciences, 19 Qingsong Road, Kunming 650203, China.
- Graduate School, University of Chinese Academy of Sciences, 19 Yuquan Road, Beijing 100049, China.
| | - Wei Ni
- Department of Neurosurgery, Tumor Hospital of Yunnan Province, 519 Kunzhou Road, Kunming 650000, China.
| | - Zhi Dai
- Key Laboratory of Animal Models and Human Disease Mechanisms of Chinese Academy of Sciences and Yunnan Province, Kunming Institute of Zoology, Chinese Academy of Sciences, 21 Qingsong Road, Kunming 650203, China.
- Kunming College of Life Science, University of Chinese Academy of Sciences, 19 Qingsong Road, Kunming 650203, China.
- Graduate School, University of Chinese Academy of Sciences, 19 Yuquan Road, Beijing 100049, China.
| | - Dong Yang
- Key Laboratory of Animal Models and Human Disease Mechanisms of Chinese Academy of Sciences and Yunnan Province, Kunming Institute of Zoology, Chinese Academy of Sciences, 21 Qingsong Road, Kunming 650203, China.
| | - Junjun Hao
- State Key Lab of Genetic Resources and Evolution, Kunming Institute of Zoology, Chinese Academy of Sciences, 21 Qingsong Road, Kunming 650203, China.
| | - Lin Luo
- Department of Neurosurgery, Tumor Hospital of Yunnan Province, 519 Kunzhou Road, Kunming 650000, China.
| | - Yaping Liu
- State Key Laboratory of Phytochemistry and Plant Resources in West China, Kunming Institute of Botany, Chinese Academy of Sciences, 132 Lanhei Road, Kunming 650201, China.
| | - Xiaodong Luo
- State Key Laboratory of Phytochemistry and Plant Resources in West China, Kunming Institute of Botany, Chinese Academy of Sciences, 132 Lanhei Road, Kunming 650201, China.
| | - Xudong Zhao
- Key Laboratory of Animal Models and Human Disease Mechanisms of Chinese Academy of Sciences and Yunnan Province, Kunming Institute of Zoology, Chinese Academy of Sciences, 21 Qingsong Road, Kunming 650203, China.
- Kunming Primate Research Center, Chinese Academy of Sciences, 32 East Jiaochang Road, Kunming 650223, China.
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Holcik M. Could the eIF2α-Independent Translation Be the Achilles Heel of Cancer? Front Oncol 2015; 5:264. [PMID: 26636041 PMCID: PMC4659918 DOI: 10.3389/fonc.2015.00264] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2015] [Accepted: 11/12/2015] [Indexed: 12/24/2022] Open
Abstract
Eukaryotic initiation factor eIF2 is a key component of the ternary complex whose role is to deliver initiator tRNA into the ribosome. A variety of stimuli, both physiologic and pathophysiologic activate eIF2 kinases that phosphorylate the α subunit of eIF2, preventing it from forming the ternary complex, thus attenuating cellular protein synthesis. Paradoxically, in cancer cells, the phosphorylation of eIF2α is associated with activation of survival pathways. This review explores the recently emerged novel mechanism of eIF2α-independent translation initiation. This mechanism, which appears to be shared by some RNA viruses and Internal Ribosome Entry Site-containing cellular mRNAs and utilizes auxiliary proteins, such as eIF5B, eIF2D, and MCT-1, is responsible for the selective translation of cancer-associated genes and could represent a weak point amenable to specific targeting for the treatment of cancer.
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Affiliation(s)
- Martin Holcik
- Department of Pediatrics, Apoptosis Research Centre, Children's Hospital of Eastern Ontario Research Institute, University of Ottawa , Ottawa, ON , Canada
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10
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Schleich S, Strassburger K, Janiesch PC, Koledachkina T, Miller KK, Haneke K, Cheng YS, Kuechler K, Stoecklin G, Duncan KE, Teleman AA. DENR-MCT-1 promotes translation re-initiation downstream of uORFs to control tissue growth. Nature 2014; 512:208-212. [PMID: 25043021 PMCID: PMC4134322 DOI: 10.1038/nature13401] [Citation(s) in RCA: 122] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2013] [Accepted: 04/23/2014] [Indexed: 01/01/2023]
Abstract
During cap-dependent eukaryotic translation initiation, ribosomes scan messenger RNA from the 5' end to the first AUG start codon with favourable sequence context. For many mRNAs this AUG belongs to a short upstream open reading frame (uORF), and translation of the main downstream ORF requires re-initiation, an incompletely understood process. Re-initiation is thought to involve the same factors as standard initiation. It is unknown whether any factors specifically affect translation re-initiation without affecting standard cap-dependent translation. Here we uncover the non-canonical initiation factors density regulated protein (DENR) and multiple copies in T-cell lymphoma-1 (MCT-1; also called MCTS1 in humans) as the first selective regulators of eukaryotic re-initiation. mRNAs containing upstream ORFs with strong Kozak sequences selectively require DENR-MCT-1 for their proper translation, yielding a novel class of mRNAs that can be co-regulated and that is enriched for regulatory proteins such as oncogenic kinases. Collectively, our data reveal that cells have a previously unappreciated translational control system with a key role in supporting proliferation and tissue growth.
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Affiliation(s)
- Sibylle Schleich
- German Cancer Research Center (DKFZ), Heidelberg, Germany
- Center for Molecular Neurobiology (ZMNH), University Medical Center Hamburg-Eppendorf (UKE), Falkenried 94, 20251 Hamburg, Germany
| | | | - Philipp Christoph Janiesch
- Center for Molecular Neurobiology (ZMNH), University Medical Center Hamburg-Eppendorf (UKE), Falkenried 94, 20251 Hamburg, Germany
| | - Tatyana Koledachkina
- Center for Molecular Neurobiology (ZMNH), University Medical Center Hamburg-Eppendorf (UKE), Falkenried 94, 20251 Hamburg, Germany
| | - Katharine K Miller
- Center for Molecular Neurobiology (ZMNH), University Medical Center Hamburg-Eppendorf (UKE), Falkenried 94, 20251 Hamburg, Germany
| | - Katharina Haneke
- German Cancer Research Center (DKFZ), Heidelberg, Germany
- Zentrum für Molekulare Biologie der Universität Heidelberg (ZMBH), DKFZ-ZMBH Alliance, Heidelberg, Germany
| | | | - Katrin Kuechler
- Center for Molecular Neurobiology (ZMNH), University Medical Center Hamburg-Eppendorf (UKE), Falkenried 94, 20251 Hamburg, Germany
| | - Georg Stoecklin
- German Cancer Research Center (DKFZ), Heidelberg, Germany
- Zentrum für Molekulare Biologie der Universität Heidelberg (ZMBH), DKFZ-ZMBH Alliance, Heidelberg, Germany
| | - Kent E Duncan
- Center for Molecular Neurobiology (ZMNH), University Medical Center Hamburg-Eppendorf (UKE), Falkenried 94, 20251 Hamburg, Germany
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11
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Shih HJ, Chen HH, Chen YA, Wu MH, Liou GG, Chang WW, Chen L, Wang LH, Hsu HL. Targeting MCT-1 oncogene inhibits Shc pathway and xenograft tumorigenicity. Oncotarget 2013; 3:1401-15. [PMID: 23211466 PMCID: PMC3717801 DOI: 10.18632/oncotarget.688] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
Overexpression of Shc adaptor proteins is associated with mitogenesis, carcinogenesis and metastasis. Multiple copies in T-cell malignancy 1 (MCT-1) oncoprotein promotes cell proliferation, survival and tumorigenic effects. Our current data show that MCT-1 is a novel regulator of Shc-Ras-MEK-ERK signaling and MCT-1 is significantly co-activated with Shc gene in human carcinomas. The knockdown of MCT-1 enhances apoptotic cell death accompanied with the activation of caspases and cleavage of caspase substrates under environmental stress. The cancer cell proliferation, chemo-resistance and tumorigenic capacity are proved to be effectively suppressed by targeting MCT-1. Accordingly, an important linkage between MCT-1 oncogenicity and Shc pathway in tumor development has now been established. Promoting MCT-1 expression by gene hyperactivation may be recognized as a tumor marker and MCT-1 may serve as a molecular target of cancer therapy.
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Affiliation(s)
- Hung-Ju Shih
- Institute of Molecular and Genomic Medicine, National Health Research Institutes, Taiwan
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Shih HJ, Chu KL, Wu MH, Wu PH, Chang WW, Chu JS, Wang LHC, Takeuchi H, Ouchi T, Hsu HL. The involvement of MCT-1 oncoprotein in inducing mitotic catastrophe and nuclear abnormalities. Cell Cycle 2012; 11:934-52. [PMID: 22336915 DOI: 10.4161/cc.11.5.19452] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Centrosome amplification and chromosome abnormality are frequently identified in neoplasia and tumorigenesis. However, the mechanisms underlying these defects remain unclear. We here identify that MCT-1 is a centrosomal oncoprotein involved in mitosis. Knockdown of MCT-1 protein results in intercellular bridging, chromosome mis-congregation, cytokinesis delay, and mitotic death. Introduction of MCT-1 oncogene into the p53 deficient cells (MCT-1-p53), the mitotic checkpoint kinases and proteins are deregulated synergistically. These biochemical alterations are accompanied with increased frequencies of cytokinesis failure, multi-nucleation, and centrosome amplification in subsequent cell cycle. As a result, the incidences of polyploidy and aneuploidy are progressively induced by prolonged cell cultivation or further promoted by sustained spindle damage on MCT-1-p53 background. These data show that the oncoprotein perturbs centrosome structure and mitotic progression, which provide the molecular aspect of chromsomal abnormality in vitro and the information for understanding the stepwise progression of tumors under oncogenic stress.
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Affiliation(s)
- Hung-Ju Shih
- Institute of Molecular and Genomic Medicine, National Health Research Institutes, Miaoli, Taiwan
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The novel anti-MEK small molecule AZD6244 induces BIM-dependent and AKT-independent apoptosis in diffuse large B-cell lymphoma. Blood 2011; 118:1052-61. [PMID: 21628402 DOI: 10.1182/blood-2011-03-340109] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
The RAS/RAF/MEK/ERK signaling pathway has been largely unexplored as a potential therapeutic target in lymphoma. The novel 2nd generation anti-MEK small molecule, AZD6244, down-regulated its direct downstream target, phospho-ERK (pERK) in germinal center and nongerminal center diffuse large B-cell lymphoma (DLBCL) cell lines and primary cells. Similar decreased pERK levels were noted despite constitutive activation (CA) of MEK. Consequently, several lymphoma-related ERK substrates were down-regulated by AZD6244 including MCT-1, c-Myc, Bcl-2, Mcl-1, and CDK1/2. AZD6244 induced time- and dose-dependent antiproliferation and apoptosis in all DLBCL cell lines and fresh/primary cells (IC(50) 100nM-300nM). Furthermore, AZD6244 resulted in significantly less tumor compared with control in an in vivo DLBCL SCID xenograft model. Cell death was associated with cleaved PARP, caspases-8, -9, and -3, and apoptosis was caspase-dependent. In addition, there was stabilization of FoxO3a, activation of BIM and PUMA, and a significant decrease in c-Myc transcripts. Moreover, siRNA knockdown of BIM abrogated AZD6244-related apoptosis, while shRNA knockdown of ERK minimally sensitized cells. Finally, manipulation of AKT with transfection of OCI-LY3 cells with CA-AKT or through chemical inhibition (LY294002) had minimal effect on AZD6244-induced cell death. Altogether, these findings show that the novel anti-MEK agent, AZD6244, induced apoptosis in DLBCL and that cell death was BIM-dependent.
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Wilson WH, Hernandez-Ilizaliturri FJ, Dunleavy K, Little RF, O'Connor OA. Novel disease targets and management approaches for diffuse large B-cell lymphoma. Leuk Lymphoma 2011; 51 Suppl 1:1-10. [PMID: 20658952 DOI: 10.3109/10428194.2010.500045] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Diffuse large B-cell lymphoma (DLBCL) responds well to treatment with CHOP and the R-CHOP regimen, but a subset of patients still fail to achieve complete or durable responses. Recent advances in gene expression profiling have led to the identification of three different subtypes of DLBCL, and confirmed that patients with the activated B-cell (ABC) disease subtype are less likely to respond well to CHOP-based regimens than those with germinal centre B-cell-type (GCB) disease. This discovery could herald the use of gene expression profiling to aid treatment decisions in DLBCL, and help identify the most effective management strategies for patients. Treatment options for patients with relapsed or refractory DLBCL are limited and several novel agents are being developed to address this unmet clinical need. Novel agents developed to treat plasma cell disorders such as multiple myeloma have shown promising activity in patients with NHL. Indeed, the immunomodulatory agent lenalidomide and the proteasome inhibitors bortezomib and carfilzomib, as single agents or in combination with chemotherapy, have already demonstrated promising activity in patients with the ABC subtype of DLBCL. One should not be complacent however when applying these agents to new disease types, because dose and drug scheduling can have marked effects on the responses achieved with investigational agents. As more targeted agents are developed, the timing of administration with other agents in clinical trials will become increasingly important to ensure maximal efficacy while minimizing side effects.
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Affiliation(s)
- Wyndham H Wilson
- Metabolism Branch, Center for Cancer Research, National Cancer Institute, Bethesda, MD 20892, USA.
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16
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Targeting the translational machinery as a novel treatment strategy for hematologic malignancies. Blood 2010; 115:2127-35. [PMID: 20075156 DOI: 10.1182/blood-2009-09-220020] [Citation(s) in RCA: 78] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
The dysregulation of protein synthesis evident in the transformed phenotype has opened up a burgeoning field of research in cancer biology. Translation initiation has recently been shown to be a common downstream target of signal transduction pathways deregulated in cancer and initiated by mutated/overexpressed oncogenes and tumor suppressors. The overexpression and/or activation of proteins involved in translation initiation such as eIF4E, mTOR, and eIF4G have been shown to induce a malignant phenotype. Therefore, understanding the mechanisms that control protein synthesis is emerging as an exciting new research area with significant potential for developing innovative therapies. This review highlights molecules that are activated or dysregulated in hematologic malignancies, and promotes the transformed phenotype through the deregulation of protein synthesis. Targeting these proteins with small molecule inhibitors may constitute a novel therapeutic approach in the treatment of cancer.
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Dai B, Zhao XF, Hagner P, Shapiro P, Mazan-Mamczarz K, Zhao S, Natkunam Y, Gartenhaus RB. Extracellular signal-regulated kinase positively regulates the oncogenic activity of MCT-1 in diffuse large B-cell lymphoma. Cancer Res 2009; 69:7835-43. [PMID: 19789340 DOI: 10.1158/0008-5472.can-09-1606] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
The MCT-1 oncogene was originally identified from lymphoma cell lines. Herein we establish that MCT-1 is highly expressed in 85% of human diffuse large B-cell lymphomas (DLBCL) and that knocking down MCT-1 by a specific short hairpin RNA in DLBCL cells induces apoptosis, supporting a critical role for MCT-1 in DLBCL cell survival. However, the mechanism underlying MCT-1 regulation is largely unknown. We find that MCT-1 is phosphorylated and up-regulated by extracellular signal-regulated kinase (ERK). Furthermore, by using a small inhibitory molecule targeting ERK, we interrupted MCT-1 phosphorylation and stability. Significantly, cells with distinct levels of MCT-1 protein displayed differential sensitivity to ERK inhibitor-induced apoptosis. Treatment with the ERK inhibitor showed marked in vivo antitumor activity in a human DLBCL xenograft model. Our findings establish a functional molecular interaction between MCT-1 and the MEK/ERK signaling pathway and suggest that the activation of MCT-1 function by its upstream kinase ERK plays an important role in lymphomagenesis.
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Affiliation(s)
- Bojie Dai
- University of Maryland Greenebaum Cancer Center, Baltimore, MD 21201, USA
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Kasiappan R, Shih HJ, Chu KL, Chen WT, Liu HP, Huang SF, Choy CO, Shu CL, Din R, Chu JS, Hsu HL. Loss of p53 and MCT-1 Overexpression Synergistically Promote Chromosome Instability and Tumorigenicity. Mol Cancer Res 2009; 7:536-48. [PMID: 19372582 DOI: 10.1158/1541-7786.mcr-08-0422] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Affiliation(s)
- Ravi Kasiappan
- National Health Research Institutes, Taiwan, Republic of China
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