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Tracing the lactate shuttle to the mitochondrial reticulum. EXPERIMENTAL & MOLECULAR MEDICINE 2022; 54:1332-1347. [PMID: 36075947 PMCID: PMC9534995 DOI: 10.1038/s12276-022-00802-3] [Citation(s) in RCA: 24] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/31/2021] [Revised: 01/02/2022] [Accepted: 01/05/2022] [Indexed: 11/10/2022]
Abstract
Isotope tracer infusion studies employing lactate, glucose, glycerol, and fatty acid isotope tracers were central to the deduction and demonstration of the Lactate Shuttle at the whole-body level. In concert with the ability to perform tissue metabolite concentration measurements, as well as determinations of unidirectional and net metabolite exchanges by means of arterial–venous difference (a-v) and blood flow measurements across tissue beds including skeletal muscle, the heart and the brain, lactate shuttling within organs and tissues was made evident. From an extensive body of work on men and women, resting or exercising, before or after endurance training, at sea level or high altitude, we now know that Organ–Organ, Cell–Cell, and Intracellular Lactate Shuttles operate continuously. By means of lactate shuttling, fuel-energy substrates can be exchanged between producer (driver) cells, such as those in skeletal muscle, and consumer (recipient) cells, such as those in the brain, heart, muscle, liver and kidneys. Within tissues, lactate can be exchanged between white and red fibers within a muscle bed and between astrocytes and neurons in the brain. Within cells, lactate can be exchanged between the cytosol and mitochondria and between the cytosol and peroxisomes. Lactate shuttling between driver and recipient cells depends on concentration gradients created by the mitochondrial respiratory apparatus in recipient cells for oxidative disposal of lactate. Studies using isotope tracer technologies have significantly improved understanding of how lactate, a metabolite produced as fuel during normal metabolism and in response to exercise, moves or ‘shuttles’ throughout the body. George Brooks and colleagues at the University of California, Berkeley, USA, reviewed the history of the understanding of lactate shuttling, which has largely been informed by human studies using isotope tracer infusions during rest and exercise. Such research highlights continuous organ–organ, cell–cell, and intracellular lactate shuttling. Lactate moves between producer cells such as skeletal muscle cells and consumer cells in tissues including the heart and brain, where it is preferred over glucose as an energy source. Shuttling depends on lactate concentration gradients created by mitochondrial networks in recipient cells. Lactate is disposed of via oxidation.
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The RNA fold interactome of evolutionary conserved RNA structures in S. cerevisiae. Nat Commun 2020; 11:2789. [PMID: 32493961 PMCID: PMC7270185 DOI: 10.1038/s41467-020-16555-4] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2019] [Accepted: 04/29/2020] [Indexed: 12/17/2022] Open
Abstract
RNA-binding proteins play key roles in regulation of gene expression via recognition of structural features in RNA molecules. Here we apply a quantitative RNA pull-down approach to 186 evolutionary conserved RNA structures and report 162 interacting proteins. Unlike global RNA interactome capture, we associate individual RNA structures within messenger RNA with their interacting proteins. Of our binders 69% are known RNA-binding proteins, whereas some are previously unrelated to RNA binding and do not harbor canonical RNA-binding domains. While current knowledge about RNA-binding proteins relates to their functions at 5′ or 3′-UTRs, we report a significant number of them binding to RNA folds in the coding regions of mRNAs. Using an in vivo reporter screen and pulsed SILAC, we characterize a subset of mRNA-RBP pairs and thus connect structural RNA features to functionality. Ultimately, we here present a generic, scalable approach to interrogate the increasing number of RNA structural motifs. Previous study identified in vivo structured mRNA regions in Saccharomyces cerevisiae by dimethyl sulfate-sequencing. Here the authors use quantitative proteomics to identify protein interactors of 186 RNA folds in S. cerevisiae, providing functional links between RNA binding proteins and distinct mRNA fold.
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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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Abstract
The non-canonical initiation factors DENR and MCTS1 have been linked to cancer and autism. We recently showed in Drosophila that DENR and MCTS1 regulate translation re-initiation on transcripts containing upstream Open Reading Frames (uORFs) with strong Kozak sequences (stuORFs). Due to the medical relevance of DENR and MCTS1, it is worthwhile identifying the transcripts in human cells that depend on DENR and MCTS1 for their translation. We show here that in humans, as in Drosophila, transcripts with short stuORFs require DENR and MCTS1 for their optimal expression. In contrast to Drosophila, however, the dependence on stuORF length in human cells is very strong, so that only transcripts with very short stuORFs coding for 1 amino acid are dependent on DENR and MCTS1. This identifies circa 100 genes as putative DENR and MCTS1 translational targets. These genes are enriched for neuronal genes and G protein-coupled receptors. The identification of DENR and MCTS1 target transcripts will serve as a basis for future studies aimed at understanding the mechanistic involvement of DENR and MCTS1 in cancer and autism.
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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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Zhou JW, Li Y, Yue LX, Luo CL, Chen Y, Zhang JY. Autoantibody response to Sui1 and its tissue-specific expression in hepatocellular carcinoma. Tumour Biol 2015; 37:2547-53. [DOI: 10.1007/s13277-015-4074-y] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2015] [Accepted: 09/13/2015] [Indexed: 01/09/2023] Open
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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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Tempel W, Dimov S, Tong Y, Park HW, Hong BS. Crystal structure of human multiple copies in T-cell lymphoma-1 oncoprotein. Proteins 2012; 81:519-25. [DOI: 10.1002/prot.24198] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2012] [Revised: 09/09/2012] [Accepted: 09/19/2012] [Indexed: 12/20/2022]
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Abstract
Posttranscriptional mechanisms are now widely acknowledged to play a central role in orchestrating gene-regulatory networks in hematopoietic cell growth, differentiation, and tumorigenesis. Although much attention has focused on microRNAs as regulators of mRNA stability/translation, recent data have highlighted the role of several diverse classes of AU-rich RNA-binding protein in the regulation of mRNA decay/stabilization. AU-rich elements are found in the 3'-untranslated region of many mRNAs that encode regulators of cell growth and survival, such as cytokines and onco/tumor-suppressor proteins. These are targeted by a burgeoning number of different RNA-binding proteins. Three distinct types of AU-rich RNA binding protein (ARE poly-U-binding degradation factor-1/AUF1, Hu antigen/HuR/HuA/ELAVL1, and the tristetraprolin/ZFP36 family of proteins) are essential for normal hematopoiesis. Together with 2 further AU-rich RNA-binding proteins, nucleolin and KHSRP/KSRP, the functions of these proteins are intimately associated with pathways that are dysregulated in various hematopoietic malignancies. Significantly, all of these AU-rich RNA-binding proteins function via an interconnected network that is integrated with microRNA functions. Studies of these diverse types of RNA binding protein are providing novel insight into gene-regulatory mechanisms in hematopoiesis in addition to offering new opportunities for developing mechanism-based targeted therapeutics in leukemia and lymphoma.
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McCole RB, Loughran NB, Chahal M, Fernandes LP, Roberts RG, Fraternali F, O'Connell MJ, Oakey RJ. A case-by-case evolutionary analysis of four imprinted retrogenes. Evolution 2011; 65:1413-27. [PMID: 21166792 PMCID: PMC3107425 DOI: 10.1111/j.1558-5646.2010.01213.x] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2010] [Accepted: 11/30/2010] [Indexed: 11/29/2022]
Abstract
Retroposition is a widespread phenomenon resulting in the generation of new genes that are initially related to a parent gene via very high coding sequence similarity. We examine the evolutionary fate of four retrogenes generated by such an event; mouse Inpp5f_v2, Mcts2, Nap1l5, and U2af1-rs1. These genes are all subject to the epigenetic phenomenon of parental imprinting. We first provide new data on the age of these retrogene insertions. Using codon-based models of sequence evolution, we show these retrogenes have diverse evolutionary trajectories, including divergence from the parent coding sequence under positive selection pressure, purifying selection pressure maintaining parent-retrogene similarity, and neutral evolution. Examination of the expression pattern of retrogenes shows an atypical, broad pattern across multiple tissues. Protein 3D structure modeling reveals that a positively selected residue in U2af1-rs1, not shared by its parent, may influence protein conformation. Our case-by-case analysis of the evolution of four imprinted retrogenes reveals that this interesting class of imprinted genes, while similar in regulation and sequence characteristics, follow very varied evolutionary paths.
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Affiliation(s)
- Ruth B McCole
- Department of Medical and Molecular Genetics, King's College LondonLondon SE1 9RT, United Kingdom
- E-mail:
| | - Noeleen B Loughran
- Bioinformatics and Molecular Evolution Group, School of Biotechnology, Faculty of Science and Health, Dublin City UniversityGlasnevin Dublin 9, Ireland
- Centre for Scientific Computing & Complex Systems modeling (SCI-SYM), Dublin City UniversityGlasnevin Dublin 9, Ireland
- E-mail:
| | - Mandeep Chahal
- Department of Medical and Molecular Genetics, King's College LondonLondon SE1 9RT, United Kingdom
- E-mail:
| | - Luis P Fernandes
- Randall Division of Cell and Molecular Biophysics, King's College LondonLondon SE1 1UL, United Kingdom
- E-mail:
| | - Roland G Roberts
- Department of Medical and Molecular Genetics, King's College LondonLondon SE1 9RT, United Kingdom
- E-mail:
| | - Franca Fraternali
- Randall Division of Cell and Molecular Biophysics, King's College LondonLondon SE1 1UL, United Kingdom
- E-mail:
| | - Mary J O'Connell
- Bioinformatics and Molecular Evolution Group, School of Biotechnology, Faculty of Science and Health, Dublin City UniversityGlasnevin Dublin 9, Ireland
- Centre for Scientific Computing & Complex Systems modeling (SCI-SYM), Dublin City UniversityGlasnevin Dublin 9, Ireland
- E-mail:
| | - Rebecca J Oakey
- Department of Medical and Molecular Genetics, King's College LondonLondon SE1 9RT, United Kingdom
- E-mail:
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Skabkin MA, Skabkina OV, Dhote V, Komar AA, Hellen CUT, Pestova TV. Activities of Ligatin and MCT-1/DENR in eukaryotic translation initiation and ribosomal recycling. Genes Dev 2010; 24:1787-801. [PMID: 20713520 DOI: 10.1101/gad.1957510] [Citation(s) in RCA: 168] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Eukaryotic translation initiation begins with ribosomal recruitment of aminoacylated initiator tRNA (Met-tRNA(Met)(i)) by eukaryotic initiation factor eIF2. In cooperation with eIF3, eIF1, and eIF1A, Met-tRNA(Met)(i)/eIF2/GTP binds to 40S subunits yielding 43S preinitiation complexes that attach to the 5'-terminal region of mRNAs and then scan to the initiation codon to form 48S initiation complexes with established codon-anticodon base-pairing. Stress-activated phosphorylation of eIF2alpha reduces the level of active eIF2, globally inhibiting translation. However, translation of several viral mRNAs, including Sindbis virus (SV) 26S mRNA and mRNAs containing hepatitis C virus (HCV)-like IRESs, is wholly or partially resistant to inhibition by eIF2 phosphorylation, despite requiring Met-tRNA(Met)(i). Here we report the identification of related proteins that individually (Ligatin) or together (the oncogene MCT-1 and DENR, which are homologous to N-terminal and C-terminal regions of Ligatin, respectively) promote efficient eIF2-independent recruitment of Met-tRNA(Met)(i) to 40S/mRNA complexes, if attachment of 40S subunits to the mRNA places the initiation codon directly in the P site, as on HCV-like IRESs and, as we show here, SV 26S mRNA. In addition to their role in initiation, Ligatin and MCT-1/DENR can promote release of deacylated tRNA and mRNA from recycled 40S subunits after ABCE1-mediated dissociation of post-termination ribosomes.
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Affiliation(s)
- Maxim A Skabkin
- Department of Cell Biology, State University of New York Downstate Medical Center, Brooklyn, NY 11203, USA
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Isidor B, Pichon O, Baron S, David A, Le Caignec C. Deletion of the CUL4B gene in a boy with mental retardation, minor facial anomalies, short stature, hypogonadism, and ataxia. Am J Med Genet A 2010; 152A:175-80. [PMID: 20014135 DOI: 10.1002/ajmg.a.33152] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
The CUL4B gene encodes a member of Cullin-RING ubiquitin ligase complex. Point mutations in CUL4B were identified recently in patients with syndromic X-linked mental retardation (XLMR). Here, using oligoarray-based comparative genomic hybridization (array CGH), we identified a de novo deletion of the CUL4B gene in a boy with syndromic mental retardation, minor facial anomalies, short stature, delayed puberty, hypogonadism, relative macrocephaly, gait ataxia, and pes cavus, all manifestations described previously in patients with CUL4B point mutations. Interestingly, our patient also presented with aortic valvular "dysplasia" and vertebral anomalies similar to those seen in Scheuermann disease, both of which may also be part of this syndrome. This report further suggests that point mutations and deletions of the CUL4B gene lead to a recognizable phenotype. The association of facial anomalies, short stature, hypogonadism, and gait ataxia in a mentally retarded boy should prompt molecular analyses of the CUL4B gene.
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Affiliation(s)
- Bertrand Isidor
- Service de Génétique Médicale, Centre Hospitalier Universitaire de Nantes 7, Quai Moncousu, 44000 Nantes Cedex, France.
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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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