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Fernandez A, Monsen PJ, Platanias LC, Schiltz GE. Medicinal chemistry approaches to target the MNK-eIF4E axis in cancer. RSC Med Chem 2023; 14:1060-1087. [PMID: 37360400 PMCID: PMC10285747 DOI: 10.1039/d3md00121k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2023] [Accepted: 05/08/2023] [Indexed: 06/28/2023] Open
Abstract
Aberrant translation of proteins that promote cell proliferation is an essential factor that defines oncogenic processes and cancer. The process for ribosomal translation of proteins from mRNA requires an essential initiation step which is controlled by the protein eIF4E, which binds the RNA 5'-cap and forms the eIF4F complex that subsequently translates protein. Typically, eIF4E is activated by phosphorylation on Ser209 by MNK1 and MNK2 kinases. Substantial work has shown that eIF4E and MNK1/2 are dysregulated in many cancers and this axis has therefore become an active area of interest for developing new cancer therapeutics. This review summarizes and discusses recent work to develop small molecules that target different steps in the MNK-eIF4E axis as potential cancer therapeutics. The aim of this review is to cover the breadth of different molecular approaches being taken and the medicinal chemistry basis for their optimization and testing as new cancer therapeutics.
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Affiliation(s)
- Ann Fernandez
- Department of Chemistry, Northwestern University Evanston IL 60208 USA
| | - Paige J Monsen
- Department of Chemistry, Northwestern University Evanston IL 60208 USA
| | - Leonidas C Platanias
- Robert H. Lurie Comprehensive Cancer Center Chicago IL 60611 USA
- Division of Hematology-Oncology, Department of Medicine, Feinberg School of Medicine, Northwestern University Chicago IL 60611 USA
- Department of Medicine, Jesse Brown Veterans Affairs Medical Center Chicago IL 60612 USA
| | - Gary E Schiltz
- Department of Chemistry, Northwestern University Evanston IL 60208 USA
- Robert H. Lurie Comprehensive Cancer Center Chicago IL 60611 USA
- Department of Pharmacology, Northwestern University Feinberg School of Medicine Chicago IL 60611 USA
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2
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Lothong M, Sakares W, Rojsitthisak P, Tanikawa C, Matsuda K, Yodsurang V. Collagen XVII inhibits breast cancer cell proliferation and growth through deactivation of the AKT/mTOR signaling pathway. PLoS One 2021; 16:e0255179. [PMID: 34293053 PMCID: PMC8297889 DOI: 10.1371/journal.pone.0255179] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2021] [Accepted: 07/10/2021] [Indexed: 12/12/2022] Open
Abstract
Collagen XVII (COL17), a cell-matrix adhesion protein, has been found to be suppressed in breast cancer. Our previous data demonstrated a preventive role of COL17 in breast cancer invasiveness. The present study used the stable COL17-overexpressing MCF7 and MDA-MB-231 cells to reveal an anti-proliferative effect of COL17 on breast cancer cell through mTOR deactivation. Cell proliferation was negatively correlated with the expression level of COL17 in a concentration-dependent manner in both conventional and three-dimensional (3D) culture systems. The correlation was confirmed by decreased expression of the proliferative marker Ki67 in COL17-expressing cells. In addition, overexpression of COL17 reduced the clonogenicity and growth of the cells. We demonstrated that COL17 affects the AKT/mTOR signaling pathway by deactivation of AKT, mTOR and downstream effectors, particularly 4EBP1. Moreover, mice xenografted with high COL17-expressing cells exhibited delayed tumor progression and prolonged survival time. The high expression of COL17A1 gene encoding COL17 is associated with low-proliferation tumors, extended tumor-free period, and overall survival of breast cancer patients. In conclusion, our results revealed the novel function of COL17 using in vitro and in vivo models and elucidated the related pathway in breast cancer cell growth and proliferation.
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Affiliation(s)
- Muttarin Lothong
- Faculty of Pharmaceutical Sciences, Department of Pharmacology and Physiology, Chulalongkorn University, Bangkok, Thailand
| | - Watchara Sakares
- Faculty of Pharmaceutical Sciences, Department of Pharmacology and Physiology, Chulalongkorn University, Bangkok, Thailand
| | - Pornchai Rojsitthisak
- Natural Products for Ageing and Chronic Diseases Research Unit, Chulalongkorn University, Bangkok, Thailand
- Faculty of Pharmaceutical Sciences, Department of Food and Pharmaceutical Chemistry, Chulalongkorn University, Bangkok, Thailand
| | - Chizu Tanikawa
- Laboratory of Genome Technology, Human Genome Center, The Institute of Medical Science, The University of Tokyo, Tokyo, Japan
| | - Koichi Matsuda
- Laboratory of Genome Technology, Human Genome Center, The Institute of Medical Science, The University of Tokyo, Tokyo, Japan
- Department of Computational Biology and Medical Sciences, Laboratory of Clinical Genome Sequencing, Graduate School of Frontier Sciences, The University of Tokyo, Tokyo, Japan
| | - Varalee Yodsurang
- Faculty of Pharmaceutical Sciences, Department of Pharmacology and Physiology, Chulalongkorn University, Bangkok, Thailand
- Preclinical Toxicity and Efficacy Assessment of Medicines and Chemicals Research Cluster, Chulalongkorn University, Bangkok, Thailand
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3
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Odle RI, Florey O, Ktistakis NT, Cook SJ. CDK1, the Other 'Master Regulator' of Autophagy. Trends Cell Biol 2020; 31:95-107. [PMID: 33272830 DOI: 10.1016/j.tcb.2020.11.001] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2020] [Revised: 10/30/2020] [Accepted: 11/03/2020] [Indexed: 12/13/2022]
Abstract
Autophagy and cap-dependent mRNA translation are tightly regulated by the mechanistic target of rapamycin complex 1 (mTORC1) signalling complex in response to nutrient availability. However, the regulation of these processes, and mTORC1 itself, is different during mitosis, and this has remained an area of significant controversy; for example, studies have argued that autophagy is either repressed or highly active during mitosis. Recent studies have shown that autophagy initiation is repressed, and cap-dependent mRNA translation is maintained during mitosis despite mTORC1 activity being repressed. This is achieved in large part by a switch from mTORC1- to cyclin-dependent kinase 1 (CDK1)-mediated regulation. Here, we review the history and recent advances and seek to present a unifying model to inform the future study of autophagy and mTORC1 during mitosis.
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Affiliation(s)
- Richard I Odle
- Signalling Laboratory, The Babraham Institute, Babraham Research Campus, Cambridge, CB22 3AT, UK
| | - Oliver Florey
- Signalling Laboratory, The Babraham Institute, Babraham Research Campus, Cambridge, CB22 3AT, UK
| | - Nicholas T Ktistakis
- Signalling Laboratory, The Babraham Institute, Babraham Research Campus, Cambridge, CB22 3AT, UK
| | - Simon J Cook
- Signalling Laboratory, The Babraham Institute, Babraham Research Campus, Cambridge, CB22 3AT, UK.
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4
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Odle RI, Walker SA, Oxley D, Kidger AM, Balmanno K, Gilley R, Okkenhaug H, Florey O, Ktistakis NT, Cook SJ. An mTORC1-to-CDK1 Switch Maintains Autophagy Suppression during Mitosis. Mol Cell 2020; 77:228-240.e7. [PMID: 31733992 PMCID: PMC6964153 DOI: 10.1016/j.molcel.2019.10.016] [Citation(s) in RCA: 64] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2019] [Revised: 07/19/2019] [Accepted: 10/10/2019] [Indexed: 01/09/2023]
Abstract
Since nuclear envelope breakdown occurs during mitosis in metazoan cells, it has been proposed that macroautophagy must be inhibited to maintain genome integrity. However, repression of macroautophagy during mitosis remains controversial and mechanistic detail limited to the suggestion that CDK1 phosphorylates VPS34. Here, we show that initiation of macroautophagy, measured by the translocation of the ULK complex to autophagic puncta, is repressed during mitosis, even when mTORC1 is inhibited. Indeed, mTORC1 is inactive during mitosis, reflecting its failure to localize to lysosomes due to CDK1-dependent RAPTOR phosphorylation. While mTORC1 normally represses autophagy via phosphorylation of ULK1, ATG13, ATG14, and TFEB, we show that the mitotic phosphorylation of these autophagy regulators, including at known repressive sites, is dependent on CDK1 but independent of mTOR. Thus, CDK1 substitutes for inhibited mTORC1 as the master regulator of macroautophagy during mitosis, uncoupling autophagy regulation from nutrient status to ensure repression of macroautophagy during mitosis.
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Affiliation(s)
- Richard I Odle
- Signalling Laboratory, The Babraham Institute, Babraham Research Campus, Cambridge CB22 3AT, UK.
| | - Simon A Walker
- Imaging Facility, The Babraham Institute, Babraham Research Campus, Cambridge CB22 3AT, UK
| | - David Oxley
- Proteomics Facility, The Babraham Institute, Babraham Research Campus, Cambridge CB22 3AT, UK
| | - Andrew M Kidger
- Signalling Laboratory, The Babraham Institute, Babraham Research Campus, Cambridge CB22 3AT, UK
| | - Kathryn Balmanno
- Signalling Laboratory, The Babraham Institute, Babraham Research Campus, Cambridge CB22 3AT, UK
| | - Rebecca Gilley
- Signalling Laboratory, The Babraham Institute, Babraham Research Campus, Cambridge CB22 3AT, UK
| | - Hanneke Okkenhaug
- Imaging Facility, The Babraham Institute, Babraham Research Campus, Cambridge CB22 3AT, UK
| | - Oliver Florey
- Signalling Laboratory, The Babraham Institute, Babraham Research Campus, Cambridge CB22 3AT, UK
| | - Nicholas T Ktistakis
- Signalling Laboratory, The Babraham Institute, Babraham Research Campus, Cambridge CB22 3AT, UK
| | - Simon J Cook
- Signalling Laboratory, The Babraham Institute, Babraham Research Campus, Cambridge CB22 3AT, UK.
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5
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Barroso-Chinea P, Luis-Ravelo D, Fumagallo-Reading F, Castro-Hernandez J, Salas-Hernandez J, Rodriguez-Nuñez J, Febles-Casquero A, Cruz-Muros I, Afonso-Oramas D, Abreu-Gonzalez P, Moratalla R, Millan MJ, Gonzalez-Hernandez T. DRD3 (dopamine receptor D3) but not DRD2 activates autophagy through MTORC1 inhibition preserving protein synthesis. Autophagy 2019; 16:1279-1295. [PMID: 31538542 DOI: 10.1080/15548627.2019.1668606] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Growing evidence shows that autophagy is deficient in neurodegenerative and psychiatric diseases, and that its induction may have beneficial effects in these conditions. However, as autophagy shares signaling pathways with cell death and interferes with protein synthesis, prolonged use of autophagy inducers available nowadays is considered unwise. The search for novel autophagy inducers indicates that DRD2 (dopamine receptor 2)-DRD3 ligands may also activate autophagy, though critical aspects of the action mechanisms and effects of dopamine ligands on autophagy are still unknown. In order to shed light on this issue, DRD2- and DRD3-overexpressing cells and drd2 KO, drd3 KO and wild-type mice were treated with the DRD2-DRD3 agonist pramipexole. The results revealed that pramipexole induces autophagy through MTOR inhibition and a DRD3-dependent but DRD2-independent mechanism. DRD3 activated AMPK followed by inhibitory phosphorylation of RPTOR, MTORC1 and RPS6KB1 inhibition and ULK1 activation. Interestingly, despite RPS6KB1 inhibition, the activity of RPS6 was maintained through activation of the MAPK1/3-RPS6KA pathway, and the activity of MTORC1 kinase target EIF4EBP1 along with protein synthesis and cell viability, were also preserved. This pattern of autophagy through MTORC1 inhibition without suppression of protein synthesis, contrasts with that of direct allosteric and catalytic MTOR inhibitors and opens up new opportunities for G protein-coupled receptor ligands as autophagy inducers in the treatment of neurodegenerative and psychiatric diseases. ABBREVIATIONS AKT/Protein kinase B: thymoma viral proto-oncogene 1; AMPK: AMP-activated protein kinase; BECN1: beclin 1; EGFP: enhanced green fluorescent protein; EIF4EBP1/4E-BP1: eukaryotic translation initiation factor 4E binding protein 1; GPCR; G protein-coupled receptor; GFP: green fluorescent protein; HEK: human embryonic kidney; MAP1LC3/LC3: microtubule-associated protein 1 light chain 3; MAP2K/MEK: mitogen-activated protein kinase kinase; MAPK1/ERK2: mitogen-activated protein kinase 1; MAPK3/ERK1: mitogen-activated protein kinase 3; MDA: malonildialdehyde; MTOR: mechanistic target of rapamycin kinase; MTT: 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide; PPX: pramipexole; RPTOR/raptor: regulatory associated protein of MTOR, complex 1; RPS6: ribosomal protein S6; RPS6KA/p90S6K: ribosomal protein S6 kinase A; RPS6KB1/p70S6K: ribosomal protein S6 kinase B1; SQSTM1/p62: sequestosome 1; ULK1: unc-51 like autophagy activating kinase 1; WT: wild type.
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Affiliation(s)
- Pedro Barroso-Chinea
- Departamento de Ciencias Médicas Básicas, Facultad de Medicina, Universidad de La Laguna , Tenerife, Spain.,Instituto de Tecnologías Biomédicas (ITB), Universidad de La Laguna , Tenerife, Spain
| | - Diego Luis-Ravelo
- Departamento de Ciencias Médicas Básicas, Facultad de Medicina, Universidad de La Laguna , Tenerife, Spain.,Instituto de Tecnologías Biomédicas (ITB), Universidad de La Laguna , Tenerife, Spain
| | - Felipe Fumagallo-Reading
- Departamento de Ciencias Médicas Básicas, Facultad de Medicina, Universidad de La Laguna , Tenerife, Spain.,Instituto de Tecnologías Biomédicas (ITB), Universidad de La Laguna , Tenerife, Spain
| | - Javier Castro-Hernandez
- Departamento de Ciencias Médicas Básicas, Facultad de Medicina, Universidad de La Laguna , Tenerife, Spain
| | - Josmar Salas-Hernandez
- Departamento de Ciencias Médicas Básicas, Facultad de Medicina, Universidad de La Laguna , Tenerife, Spain.,Instituto de Tecnologías Biomédicas (ITB), Universidad de La Laguna , Tenerife, Spain
| | - Julia Rodriguez-Nuñez
- Departamento de Ciencias Médicas Básicas, Facultad de Medicina, Universidad de La Laguna , Tenerife, Spain
| | - Alejandro Febles-Casquero
- Departamento de Ciencias Médicas Básicas, Facultad de Medicina, Universidad de La Laguna , Tenerife, Spain
| | - Ignacio Cruz-Muros
- Departamento de Ciencias Médicas Básicas, Facultad de Medicina, Universidad de La Laguna , Tenerife, Spain.,Instituto de Tecnologías Biomédicas (ITB), Universidad de La Laguna , Tenerife, Spain
| | - Domingo Afonso-Oramas
- Departamento de Ciencias Médicas Básicas, Facultad de Medicina, Universidad de La Laguna , Tenerife, Spain.,Instituto de Tecnologías Biomédicas (ITB), Universidad de La Laguna , Tenerife, Spain
| | - Pedro Abreu-Gonzalez
- Departamento de Ciencias Médicas Básicas, Facultad de Medicina, Universidad de La Laguna , Tenerife, Spain
| | - Rosario Moratalla
- Departamento de Biología Funcional y de Sistemas. Instituto Cajal, Consejo Superior de Investigaciones Científicas , Madrid, Spain.,CIBERNED, ISCIII , Madrid, Spain
| | - Mark J Millan
- Department of Psychopharmacology, Institut Centre de Recherches Servier , Paris, France
| | - Tomas Gonzalez-Hernandez
- Departamento de Ciencias Médicas Básicas, Facultad de Medicina, Universidad de La Laguna , Tenerife, Spain.,Instituto de Tecnologías Biomédicas (ITB), Universidad de La Laguna , Tenerife, Spain
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6
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Anda S, Grallert B. Cell-Cycle-Dependent Regulation of Translation: New Interpretations of Old Observations in Light of New Approaches. Bioessays 2019; 41:e1900022. [PMID: 31210378 DOI: 10.1002/bies.201900022] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2019] [Revised: 04/29/2019] [Indexed: 12/22/2022]
Abstract
It is a long-standing view that global translation varies during the cell cycle and is much lower in mitosis than in other cell-cycle phases. However, the central papers in the literature are not in agreement about the extent of downregulation in mitosis, ranging from a dramatic decrease to only a marginal reduction. Herein, it is argued that the discrepancy derives from technical challenges. Cell-cycle-dependent variations are most conveniently studied in synchronized cells, but the synchronization methods by themselves often evoke stress responses that, in turn, affect translation rates. Further, it is argued that previously reported cell-cycle-dependent changes in the global translation rate to a large extent reflect responses to the synchronization methods. Recent findings strongly suggest that the global translation rate is not regulated in a cell-cycle-dependent manner. Novel techniques allowing a genome-wide analysis of translational profiles suggest that the extent and importance of selective translational regulation associated with cell-cycle transitions have been underestimated. Therefore, the main question is which messenger RNAs (mRNAs) are translated, rather than whether the global translation rate is decreased.
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Affiliation(s)
- Silje Anda
- Department of Radiation Biology, Institute for Cancer Research, Oslo University Hospital, 0379, Oslo, Norway
| | - Beáta Grallert
- Department of Radiation Biology, Institute for Cancer Research, Oslo University Hospital, 0379, Oslo, Norway
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7
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Rutkovsky AC, Yeh ES, Guest ST, Findlay VJ, Muise-Helmericks RC, Armeson K, Ethier SP. Eukaryotic initiation factor 4E-binding protein as an oncogene in breast cancer. BMC Cancer 2019; 19:491. [PMID: 31122207 PMCID: PMC6533768 DOI: 10.1186/s12885-019-5667-4] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2018] [Accepted: 05/01/2019] [Indexed: 02/08/2023] Open
Abstract
BACKGROUND Eukaryotic Initiation Factor 4E-Binding Protein (EIF4EBP1, 4EBP1) is overexpressed in many human cancers including breast cancer, yet the role of 4EBP1 in breast cancer remains understudied. Despite the known role of 4EBP1 as a negative regulator of cap-dependent protein translation, 4EBP1 is predicted to be an essential driving oncogene in many cancer cell lines in vitro, and can act as a driver of cancer cell proliferation. EIF4EBP1 is located within the 8p11-p12 genomic locus, which is frequently amplified in breast cancer and is known to predict poor prognosis and resistance to endocrine therapy. METHODS Here we evaluated the effect of 4EBP1 targeting using shRNA knock-down of expression of 4EBP1, as well as response to the mTORC targeted drug everolimus in cell lines representing different breast cancer subtypes, including breast cancer cells with the 8p11-p12 amplicon, to better define a context and mechanism for oncogenic 4EBP1. RESULTS Using a genome-scale shRNA screen on the SUM panel of breast cancer cell lines, we found 4EBP1 to be a strong hit in the 8p11 amplified SUM-44 cells, which have amplification and overexpression of 4EBP1. We then found that knock-down of 4EBP1 resulted in dramatic reductions in cell proliferation in 8p11 amplified breast cancer cells as well as in other luminal breast cancer cell lines, but had little or no effect on the proliferation of immortalized but non-tumorigenic human mammary epithelial cells. Kaplan-Meier analysis of EIF4EBP1 expression in breast cancer patients demonstrated that overexpression of this gene was associated with reduced relapse free patient survival across all breast tumor subtypes. CONCLUSIONS These results are consistent with an oncogenic role of 4EBP1 in luminal breast cancer and suggests a role for this protein in cell proliferation distinct from its more well-known role as a regulator of cap-dependent translation.
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Affiliation(s)
- Alexandria C. Rutkovsky
- Department of Pathology and Laboratory Medicine, Medical University of South Carolina, 171 Ashley Avenue, MSC 908, Charleston, SC 29425 USA
- Hollings Cancer Center, Medical University of South Carolina, 86 Jonathan Lucas Street, Charleston, SC 29425 USA
| | - Elizabeth S. Yeh
- Department of Cell and Molecular Pharmacology and Experimental Therapeutics, Medical University of South Carolina, 173 Ashley Avenue, BSB 358, MSC 509, Charleston, SC 29425 USA
- Hollings Cancer Center, Medical University of South Carolina, 86 Jonathan Lucas Street, Charleston, SC 29425 USA
| | - Stephen T. Guest
- Department of Computational Medicine and Bioinformatics, University of Michigan, 500 S. State Street, Ann Arbor, MI 48109 USA
| | - Victoria J. Findlay
- Department of Pathology and Laboratory Medicine, Medical University of South Carolina, 171 Ashley Avenue, MSC 908, Charleston, SC 29425 USA
| | - Robin C. Muise-Helmericks
- Department of Regenerative Medicine and Cell Biology, Medical University of South Carolina, 173 Ashley Avenue, BSB 601, MSC 508, Charleston, SC 29425 USA
| | - Kent Armeson
- Hollings Cancer Center, Medical University of South Carolina, 86 Jonathan Lucas Street, Charleston, SC 29425 USA
- Department of Public Health Sciences, Medical University of South Carolina, 135 Cannon Street Suite 303 MSC 835, Charleston, USA
| | - Stephen P. Ethier
- Department of Pathology and Laboratory Medicine, Medical University of South Carolina, 171 Ashley Avenue, MSC 908, Charleston, SC 29425 USA
- Hollings Cancer Center, Medical University of South Carolina, 86 Jonathan Lucas Street, Charleston, SC 29425 USA
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8
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Reappraisal to the study of 4E-BP1 as an mTOR substrate – A normative critique. Eur J Cell Biol 2017; 96:325-336. [DOI: 10.1016/j.ejcb.2017.03.013] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2017] [Revised: 03/31/2017] [Accepted: 03/31/2017] [Indexed: 12/20/2022] Open
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9
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Jansova D, Koncicka M, Tetkova A, Cerna R, Malik R, del Llano E, Kubelka M, Susor A. Regulation of 4E-BP1 activity in the mammalian oocyte. Cell Cycle 2017; 16:927-939. [PMID: 28272965 PMCID: PMC5462087 DOI: 10.1080/15384101.2017.1295178] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2016] [Revised: 01/31/2017] [Accepted: 02/08/2017] [Indexed: 01/03/2023] Open
Abstract
Fully grown mammalian oocytes utilize transcripts synthetized and stored during earlier development. RNA localization followed by a local translation is a mechanism responsible for the regulation of spatial and temporal gene expression. Here we show that the mouse oocyte contains 3 forms of cap-dependent translational repressor expressed on the mRNA level: 4E-BP1, 4E-BP2 and 4E-BP3. However, only 4E-BP1 is present as a protein in oocytes, it becomes inactivated by phosphorylation after nuclear envelope breakdown and as such it promotes cap-dependent translation after NEBD. Phosphorylation of 4E-BP1 can be seen in the oocytes after resumption of meiosis but it is not detected in the surrounding cumulus cells, indicating that 4E-BP1 promotes translation at a specific cell cycle stage. Our immunofluorescence analyses of 4E-BP1 in oocytes during meiosis I showed an even localization of global 4E-BP1, as well as of its 4E-BP1 (Thr37/46) phosphorylated form. On the other hand, 4E-BP1 phosphorylated on Ser65 is localized at the spindle poles, and 4E-BP1 phosphorylated on Thr70 localizes on the spindle. We further show that the main positive regulators of 4E-BP1 phosphorylation after NEBD are mTOR and CDK1 kinases, but not PLK1 kinase. CDK1 exerts its activity toward 4E-BP1 phosphorylation via phosphorylation and activation of mTOR. Moreover, both CDK1 and phosphorylated mTOR co-localize with 4E-BP1 phosphorylated on Thr70 on the spindle at the onset of meiotic resumption. Expression of the dominant negative 4E-BP1 mutant adversely affects translation and results in spindle abnormality. Taken together, our results show that the phosphorylation of 4E-BP1 promotes translation at the onset of meiosis to support the spindle assembly and suggest an important role of CDK1 and mTOR kinases in this process. We also show that the mTOR regulatory pathway is present in human oocytes and is likely to function in a similar way as in mouse oocytes.
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Affiliation(s)
- Denisa Jansova
- Institute of Animal Physiology and Genetics, ASC, Libechov, Czech Republic
| | - Marketa Koncicka
- Institute of Animal Physiology and Genetics, ASC, Libechov, Czech Republic
| | - Anna Tetkova
- Institute of Animal Physiology and Genetics, ASC, Libechov, Czech Republic
| | - Renata Cerna
- Institute of Animal Physiology and Genetics, ASC, Libechov, Czech Republic
| | - Radek Malik
- Institute of Molecular Genetics, ASCR, Prague, Czech Republic
| | - Edgar del Llano
- Institute of Animal Physiology and Genetics, ASC, Libechov, Czech Republic
| | - Michal Kubelka
- Institute of Animal Physiology and Genetics, ASC, Libechov, Czech Republic
| | - Andrej Susor
- Institute of Animal Physiology and Genetics, ASC, Libechov, Czech Republic
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10
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Akiyama M, Sowa Y, Taniguchi T, Watanabe M, Yogosawa S, Kitawaki J, Sakai T. Three Combined Treatments, a Novel HDAC Inhibitor OBP-801/YM753, 5-Fluorouracil, and Paclitaxel, Induce G₂ Phase Arrest Through the p38 Pathway in Human Ovarian Cancer Cells. Oncol Res 2017; 25:1245-1252. [PMID: 28117030 PMCID: PMC7841106 DOI: 10.3727/096504017x14850164661097] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
Ovarian cancer is the most lethal disease among gynecological malignancies. More effective therapy is required to counter high recurrence rates and chemotherapy resistance. We investigated the efficacy and molecular mechanisms of three combined treatments (TCTs)—a novel histone deacetylase (HDAC) inhibitor OBP-801/YM753, 5-fluorouracil (5-FU), and paclitaxel (PTX)—in human ovarian cancer SKOV-3 and OVCAR-3 cells. The inhibition of cell growth was stronger with TCTs than with each single agent and with two combined treatments. The TCTs significantly induce G2 phase arrest in both cell lines. We then analyzed the molecular mechanisms and found that the TCTs increased the phosphorylation of p38 (Thr180/Tyr182), decreased the expression of CDC25C, and increased the phosphorylation of CDC2 (Tyr15), an inactive form of CDC2. To examine the responsibilities of the p38 pathway for G2 phase arrest induced by the TCTs, we employed the p38 inhibitor SB203580. SB203580 inhibited G2 phase arrest, suppression of CDC25C, and phosphorylation of CDC2 (Tyr15) induced by the TCTs. These results suggest that the TCTs can induce G2 phase arrest through activation of the p38 signaling pathway. We therefore believe that this combination is promising as a novel therapeutic strategy against ovarian cancer.
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11
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Yu ZJ, Luo HH, Shang ZF, Guan H, Xiao BB, Liu XD, Wang Y, Huang B, Zhou PK. Stabilization of 4E-BP1 by PI3K kinase and its involvement in CHK2 phosphorylation in the cellular response to radiation. Int J Med Sci 2017; 14:452-461. [PMID: 28539821 PMCID: PMC5441037 DOI: 10.7150/ijms.18329] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/13/2016] [Accepted: 03/01/2017] [Indexed: 11/16/2022] Open
Abstract
Objectives: 4E-BP1 is a family member of eIF4E binding proteins (4E-BPs) which act as the suppressors of cap-dependent translation of RNA via competitively associating with cap-bound eIF4E. RNA translation regulation is an important manner to control the cellular responses to a series of stress conditions such as ionizing radiation (IR)-induced DNA damage response and cell cycle controlling. This study aimed to determine the mechanism of 4E-BP1 stabilization and its potential downstream target(s) in the response to IR. Methods: PI3Ks kinase inhibitors were used to determine the signaling control of 4E-BP1 phosphorylation and protein stability. shRNA strategy was employed to silence the expression of 4E-BP1 in HeLa and HepG2 cells, and determine its effect on the irradiation-induced CHK2 phosphorylation. The protein degradation/stability was investigated by western blotting on the condition of blocking novel protein synthesis by cycloheximide (CHX). Results: The phosphorylation of 4E-BP1 at Thr37/46 was significantly increased in both HepG2 and HeLa cells by ionizing radiation. Depression of 4E-BP1 by shRNA strategy resulted in an incomplete G2 arrest at the early stage of 2 hours post-irradiation, as well as a higher accumulation of mitotic cells at 10 and 12 hours post-irradiation as compared to the control cells. Consistently, the CHK2 phosphorylation at Thr68 induced by IR was also attenuated by silencing 4E-BP1 expression. Both PI3K and DNA-PKcs kinase inhibitors significantly decreased the protein level of 4E-BP1, which was associated with the accelerated degradation mediated by ubiquitination-proteasome pathway. Conclusion: PI3K kinase activity is necessary for maintaining 4E-BP1 stability. Our results also suggest 4E-BP1 a novel biological role of regulating cell cycle G2 checkpoint in responding to IR stress in association with controlling CHK2 phosphorylation.
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Affiliation(s)
- Zi-Jian Yu
- Department of Hepatobiliary Surgery, the First Affiliated Hospital, University of South China, Hengyang, Hunan Province 421001, P.R. China
| | - Hui-Hui Luo
- Institute for Environmental Medicine and Radiation Health, the College of Public Health, University of South China, Hengyang, Hunan Province 421001, P.R. China.,Department of Radiation Toxicology and Oncology, Beijing Key Laboratory for Radiobiology (BKLRB), Beijing Institute of Radiation Medicine, 100850 Beijing, P.R. China
| | - Zeng-Fu Shang
- School of Radiation Medicine and Protection, Medical College of Soochow University, Collaborative Innovation Center of Radiation Medicine of Jiangsu Higher Education Institutions, Suzhou, Jiangsu Province 215123, P.R. China
| | - Hua Guan
- Department of Radiation Toxicology and Oncology, Beijing Key Laboratory for Radiobiology (BKLRB), Beijing Institute of Radiation Medicine, 100850 Beijing, P.R. China
| | - Bei-Bei Xiao
- School of Radiation Medicine and Protection, Medical College of Soochow University, Collaborative Innovation Center of Radiation Medicine of Jiangsu Higher Education Institutions, Suzhou, Jiangsu Province 215123, P.R. China
| | - Xiao-Dan Liu
- Department of Radiation Toxicology and Oncology, Beijing Key Laboratory for Radiobiology (BKLRB), Beijing Institute of Radiation Medicine, 100850 Beijing, P.R. China
| | - Yu Wang
- Department of Radiation Toxicology and Oncology, Beijing Key Laboratory for Radiobiology (BKLRB), Beijing Institute of Radiation Medicine, 100850 Beijing, P.R. China
| | - Bo Huang
- Institute for Environmental Medicine and Radiation Health, the College of Public Health, University of South China, Hengyang, Hunan Province 421001, P.R. China
| | - Ping-Kun Zhou
- Institute for Environmental Medicine and Radiation Health, the College of Public Health, University of South China, Hengyang, Hunan Province 421001, P.R. China.,Department of Radiation Toxicology and Oncology, Beijing Key Laboratory for Radiobiology (BKLRB), Beijing Institute of Radiation Medicine, 100850 Beijing, P.R. China
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12
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Abstract
Eukaryotic translation initiation factor 4E (eIF4E)-binding protein 1 (4E-BP1) is a member of a family of translation repressor proteins, and a well-known substrate of mechanistic target of rapamycin (mTOR) signaling pathway. Phosphorylation of 4E-BP1 causes its release from eIF4E to allow cap-dependent translation to proceed. Recently, 4E-BP1 was shown to be phosphorylated by other kinases besides mTOR, and overexpression of 4E-BP1 was found in different human carcinomas. In this review, we summarize the novel findings on mTOR independent 4E-BP1 phosphorylation in carcinomas. The implications of overexpression and possible multi-function of 4E-BP1 are also discussed.
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Affiliation(s)
- Xiaoyu Qin
- a Department of Oncology , Shanghai Ninth People's Hospital, Shanghai Jiaotong University School of Medicine , Shanghai , China
| | - Bin Jiang
- a Department of Oncology , Shanghai Ninth People's Hospital, Shanghai Jiaotong University School of Medicine , Shanghai , China
| | - Yanjie Zhang
- a Department of Oncology , Shanghai Ninth People's Hospital, Shanghai Jiaotong University School of Medicine , Shanghai , China
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13
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Lv T, Wang Q, Cromie M, Liu H, Tang S, Song Y, Gao W. Twist1-mediated 4E-BP1 regulation through mTOR in non-small cell lung cancer. Oncotarget 2016; 6:33006-18. [PMID: 26360779 PMCID: PMC4741745 DOI: 10.18632/oncotarget.5026] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2015] [Accepted: 07/31/2015] [Indexed: 01/16/2023] Open
Abstract
Twist1 overexpression corresponds with poor survival in non-small cell lung cancer (NSCLC), but the underlining mechanism is not clear. The objective of the present study was to investigate the tumorigenic role of Twist1 and its related molecular mechanisms in NSCLC. Twist1 was overexpressed in 34.7% of NSCLC patients. The survival rate was significantly lower in patients with high Twist1 expression than low expression (P < 0.05). Twist1 expression levels were higher in H1650 cells, but relatively lower in H1975 cells. H1650 with stable Twist1 knockdown, H1650shTw, demonstrated a significantly slower rate of wound closure; however, H1975 with stable Twist1 overexpression, H1975Over, had an increased motility velocity. A significant decrease in colony number and size was observed in H1650shTw, but a significant increase in colony number was found in H1975Over (P < 0.05). Tumor growth significantly decreased in mice implanted with H1650shTw compared to H1650 (P < 0.05). 4E-BP1 and p53 gene expressions were increased, but p-4E-BP1 and p-mTOR protein expressions were decreased in H1650shTw. However, 4E-BP1 gene expression was decreased, while p-4E-BP1 and p-mTOR protein expressions were increased in H1975Over. p-4E-BP1 was overexpressed in 24.0% of NSCLC patients. Survival rate was significantly lower in patients with high p-4E-BP1 expression than low p-4E-BP1 (P < 0.01). A significant correlation was found between Twist1 and p-4E-BP1 (P < 0.01). A total of 13 genes in RT-PCR array showed significant changes in H1650shTw. Altogether, Twist1 is correlated with p-4E-BP1 in predicting the prognostic outcome of NSCLC. Inhibition of Twist1 decreases p-4E-BP1 expression possibly through downregulating p-mTOR and increasing p53 expression in NSCLC.
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Affiliation(s)
- Tangfeng Lv
- Department of Environmental Toxicology, The Institute of Environmental and Human Health, Texas Tech University, Lubbock, Texas 79416, United States of America.,Department of Respiratory Medicine, Jinling Hospital, Nanjing, Jiangsu 210002, China
| | - Qian Wang
- Department of Environmental Toxicology, The Institute of Environmental and Human Health, Texas Tech University, Lubbock, Texas 79416, United States of America.,Department of Respiratory Medicine, Jiangsu Province Hospital of Chinese Medicine, Affiliated Hospital of Nanjing University of Chinese Medicine, Nanjing, Jiangsu 210029, China
| | - Meghan Cromie
- Department of Environmental Toxicology, The Institute of Environmental and Human Health, Texas Tech University, Lubbock, Texas 79416, United States of America
| | - Hongbing Liu
- Department of Respiratory Medicine, Jinling Hospital, Nanjing, Jiangsu 210002, China
| | - Song Tang
- Department of Environmental Toxicology, The Institute of Environmental and Human Health, Texas Tech University, Lubbock, Texas 79416, United States of America
| | - Yong Song
- Department of Respiratory Medicine, Jinling Hospital, Nanjing, Jiangsu 210002, China
| | - Weimin Gao
- Department of Environmental Toxicology, The Institute of Environmental and Human Health, Texas Tech University, Lubbock, Texas 79416, United States of America
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14
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Martínez-Sáez E, Peg V, Ortega-Aznar A, Martínez-Ricarte F, Camacho J, Hernández-Losa J, Ferreres Piñas JC, Ramón Y Cajal S. peIF4E as an independent prognostic factor and a potential therapeutic target in diffuse infiltrating astrocytomas. Cancer Med 2016; 5:2501-12. [PMID: 27440383 PMCID: PMC5055163 DOI: 10.1002/cam4.817] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2016] [Revised: 06/07/2016] [Accepted: 06/13/2016] [Indexed: 12/19/2022] Open
Abstract
Malignant transformation in tumors is a complex process requiring accumulation of numerous oncogenic abnormalities. Brain tumors show considerable phenotypic and genetic heterogeneity. In a series comprising diffuse infiltrating astrocytomas (DIA) and reactive gliosis, we investigated the main factors associated with signaling pathways. We assessed expression levels and their association with tumor progression and survival. We studied 19 grade II astrocytomas, 25 anaplastic astrocytomas (grade III), 60 glioblastomas (grade IV), and 15 cases of reactive gliosis. Epidermal growth factor receptor (EGFR), pMAPK, 4E‐BP1, p4E‐BP1, pS6, eIF4E, and peIF4E expression levels were evaluated using immunohistochemistry. Expression levels were semiquantitatively evaluated using a histoscore. Immunohistochemistry and PCR were used for IDH1 mutations. Statistical analysis was based on the following tests: chi‐square, Student's t, Pearson correlation, Spearman's rho, and Mann–Whitney; ROC and Kaplan–Meier curves were constructed. A significant increase was observed between grades for expression of total and phosphorylated 4E‐BP1 and for eIF4E, Ki67, EGFR, and cyclin D1. Although expression of EGFR, eIF4E, and Ki67 correlated with survival, only peIF4E was an independent predictor of survival in the multivariate analysis. Combining the evaluation of different proteins enables us to generate helpful diagnostic nomograms. In conclusion, cell signaling pathways are activated in DIAs; peIF4E is an independent prognostic factor and a promising therapeutic target. Joint analysis of the expression of 4E‐BP1 and peIF4E could be helpful in the diagnosis of glioblastoma multiforme in small biopsy samples.
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Affiliation(s)
- Elena Martínez-Sáez
- Department of Pathology, Vall d'Hebron University Hospital, Barcelona, Spain. .,Department of Morphological Sciences, Universitat Autònoma de Barcelona, Barcelona, Spain.
| | - Vicente Peg
- Department of Pathology, Vall d'Hebron University Hospital, Barcelona, Spain.,Department of Morphological Sciences, Universitat Autònoma de Barcelona, Barcelona, Spain
| | | | | | - Jessica Camacho
- Department of Pathology, Vall d'Hebron University Hospital, Barcelona, Spain.,Department of Morphological Sciences, Universitat Autònoma de Barcelona, Barcelona, Spain
| | | | | | - Santiago Ramón Y Cajal
- Department of Pathology, Vall d'Hebron University Hospital, Barcelona, Spain. .,Department of Morphological Sciences, Universitat Autònoma de Barcelona, Barcelona, Spain.
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15
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Mitotic protein kinase CDK1 phosphorylation of mRNA translation regulator 4E-BP1 Ser83 may contribute to cell transformation. Proc Natl Acad Sci U S A 2016; 113:8466-71. [PMID: 27402756 DOI: 10.1073/pnas.1607768113] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Mammalian target of rapamycin (mTOR)-directed eukaryotic translation initiation factor 4E-binding protein 1 (4E-BP1) phosphorylation promotes cap-dependent translation and tumorigenesis. During mitosis, cyclin-dependent kinase 1 (CDK1) substitutes for mTOR and fully phosphorylates 4E-BP1 at canonical sites (T37, T46, S65, and T70) and the noncanonical S83 site, resulting in a mitosis-specific hyperphosphorylated δ isoform. Colocalization studies with a phospho-S83 specific antibody indicate that 4E-BP1 S83 phosphorylation accumulates at centrosomes during prophase, peaks at metaphase, and decreases through telophase. Although S83 phosphorylation of 4E-BP1 does not affect general cap-dependent translation, expression of an alanine substitution mutant 4E-BP1.S83A partially reverses rodent cell transformation induced by Merkel cell polyomavirus small T antigen viral oncoprotein. In contrast to inhibitory mTOR 4E-BP1 phosphorylation, these findings suggest that mitotic CDK1-directed phosphorylation of δ-4E-BP1 may yield a gain of function, distinct from translation regulation, that may be important in tumorigenesis and mitotic centrosome function.
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16
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CDK1 substitutes for mTOR kinase to activate mitotic cap-dependent protein translation. Proc Natl Acad Sci U S A 2015; 112:5875-82. [PMID: 25883264 PMCID: PMC4434708 DOI: 10.1073/pnas.1505787112] [Citation(s) in RCA: 98] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Mitosis is commonly thought to be associated with reduced cap-dependent protein translation. Here we show an alternative control mechanism for maintaining cap-dependent translation during mitosis revealed by a viral oncoprotein, Merkel cell polyomavirus small T (MCV sT). We find MCV sT to be a promiscuous E3 ligase inhibitor targeting the anaphase-promoting complex, which increases cell mitogenesis. MCV sT binds through its Large T stabilization domain region to cell division cycle protein 20 (Cdc20) and, possibly, cdc20 homolog 1 (Cdh1) E3 ligase adapters. This activates cyclin-dependent kinase 1/cyclin B1 (CDK1/CYCB1) to directly hyperphosphorylate eukaryotic initiation factor 4E (eIF4E)-binding protein (4E-BP1) at authentic sites, generating a mitosis-specific, mechanistic target of rapamycin (mTOR) inhibitor-resistant δ phospho-isoform not present in G1-arrested cells. Recombinant 4E-BP1 inhibits capped mRNA reticulocyte translation, which is partially reversed by CDK1/CYCB1 phosphorylation of 4E-BP1. eIF4G binding to the eIF4E-m(7)GTP cap complex is resistant to mTOR inhibition during mitosis but sensitive during interphase. Flow cytometry, with and without sT, reveals an orthogonal pH3(S10+) mitotic cell population having higher inactive p4E-BP1(T37/T46+) saturation levels than pH3(S10-) interphase cells. Using a Click-iT flow cytometric assay to directly measure mitotic protein synthesis, we find that most new protein synthesis during mitosis is cap-dependent, a result confirmed using the eIF4E/4G inhibitor drug 4E1RCat. For most cell lines tested, cap-dependent translation levels were generally similar between mitotic and interphase cells, and the majority of new mitotic protein synthesis was cap-dependent. These findings suggest that mitotic cap-dependent translation is generally sustained during mitosis by CDK1 phosphorylation of 4E-BP1 even under conditions of reduced mTOR signaling.
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17
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Zhu HL, Xie SM, Fang M, Zhang JJ, Weng ZP, Zhong XY. 4E-BP1 regulates the sensitivity of human glioma cells to chemotherapy through PI3K/Akt/mTOR-independent pathway. Neuropathology 2013; 34:227-35. [PMID: 24354477 DOI: 10.1111/neup.12085] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2013] [Revised: 10/31/2013] [Accepted: 11/01/2013] [Indexed: 12/19/2022]
Abstract
Drug resistance is one of the most formidable obstacles for treatment of glioma. Eukaryotic initiation factor 4E-binding protein (4E-BP1), a key component in the rate-limiting step of protein translation initiation, is closely associated with poor prognosis in multiple tumor types. However, it is unclear whether 4E-BP1 is involved in the drug resistance of human glioma. Herein we show that the expression of 4E-BP1 in human SWOZ2-BCNU drug-resistant glioma cells is significantly lower than that of the parent SWOZ2 cell line. Moreover, down-regulation of 4E-BP1 by short interfering RNA significantly impaired the sensitivity of SWOZ2 and U251 cells to carmustine (BCNU). Furthermore, overexpression of 4E-BP1 with plasmid transfection regained this sensitivity. Clinical studies showed that the expression levels of 4E-BP1 in primary glioma tissues were markedly higher than those of recrudescent glioma tissues. Taken together, our results suggest that 4E-BP1 is a novel protein that contributes to acquired drug resistance and it may be a potential target for reversing drug resistance in human glioma.
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Affiliation(s)
- Hui-Li Zhu
- The First Affiliated Hospital of Jinan University, Guangzhou, China; Department of Pathology, Medical College of Jinan University, Guangzhou, China
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18
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Shang ZF, Yu L, Li B, Tu WZ, Wang Y, Liu XD, Guan H, Huang B, Rang WQ, Zhou PK. 4E-BP1 participates in maintaining spindle integrity and genomic stability via interacting with PLK1. Cell Cycle 2012; 11:3463-71. [PMID: 22918237 PMCID: PMC3466556 DOI: 10.4161/cc.21770] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
The essential function of eIF4E-binding protein 1 (4E-BP1) in translation initiation has been well established; however, the role of 4E-BP1 in normal cell cycle progression is coming to attention. Here, we revealed the role of 4E-BP1 on mitotic regulation and chromosomal DNA dynamics during mitosis. First, we have observed the co-localization of the phosphorylated 4E-BP1 at T37/46 with Polo-like kinase 1 (PLK1) at the centrosomes during. Depression of 4E-BP1 by small interfering RNA in HepG2 or HeLa cells resulted in an increased outcome of polyploidy and aberrant mitosis, including chromosomal DNA misaligned and multi-polar spindles or multiple centrosomes. We observed that 4E-BP1 interacted with PLK1 directly in vitro and in vivo in mitotic cells, and the C-terminal aa 77-118 of 4E-BP1 mediates its interaction with PLK1. PLK1 can phosphorylate 4E-BP1 in vitro. Furthermore, the depletion of 4E-BP1 sensitized HepG2 and HeLa cells to the microtubule disruption agent paclitaxel. These results demonstrate that 4E-BP1, beyond its role in translation regulation, can function as a regulator of mitosis via interacting with PLK1, and possibly plays a role in genomic stability maintaining.
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Affiliation(s)
- Zeng-Fu Shang
- Department of Radiation Toxicology and Oncology; Beijing Institute of Radiation Medicine; Beijing, PR China
| | - Lan Yu
- Division of Molecular Radiation Biology; Department of Radiation Oncology; University of Texas Southwestern Medical Center at Dallas; Dallas, TX USA
| | - Bing Li
- Department of Radiation Toxicology and Oncology; Beijing Institute of Radiation Medicine; Beijing, PR China
| | - Wen-Zhi Tu
- Department of Radiation Toxicology and Oncology; Beijing Institute of Radiation Medicine; Beijing, PR China
- Institute for Environmental Medicine and Radiation Hygiene; The College of Public Health; University of South China; Hengyang, PR China
| | - Yu Wang
- Department of Radiation Toxicology and Oncology; Beijing Institute of Radiation Medicine; Beijing, PR China
| | - Xiao-Dan Liu
- Department of Radiation Toxicology and Oncology; Beijing Institute of Radiation Medicine; Beijing, PR China
| | - Hua Guan
- Department of Radiation Toxicology and Oncology; Beijing Institute of Radiation Medicine; Beijing, PR China
| | - Bo Huang
- Institute for Environmental Medicine and Radiation Hygiene; The College of Public Health; University of South China; Hengyang, PR China
| | - Wei-Qing Rang
- Institute for Environmental Medicine and Radiation Hygiene; The College of Public Health; University of South China; Hengyang, PR China
| | - Ping-Kun Zhou
- Department of Radiation Toxicology and Oncology; Beijing Institute of Radiation Medicine; Beijing, PR China
- Institute for Environmental Medicine and Radiation Hygiene; The College of Public Health; University of South China; Hengyang, PR China
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19
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Chen CH, Liao CH, Chang YL, Guh JH, Pan SL, Teng CM. Protopine, a novel microtubule-stabilizing agent, causes mitotic arrest and apoptotic cell death in human hormone-refractory prostate cancer cell lines. Cancer Lett 2011; 315:1-11. [PMID: 22033245 DOI: 10.1016/j.canlet.2011.09.042] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2011] [Revised: 09/22/2011] [Accepted: 09/29/2011] [Indexed: 10/16/2022]
Abstract
In this study, we investigated the anticancer effect of protopine on human hormone-refractory prostate cancer (HRPC) cells. Protopine exhibited an anti-proliferative effect by induction of tubulin polymerization and mitotic arrest, which ultimately led to apoptotic cell death. The data suggest that protopine increased the activity of cyclin-dependent kinase 1 (Cdk1)/cyclin B1 complex and that contributed to cell apoptosis by modulating mitochondria-mediated signaling pathways, such as Bcl-2 phosphorylation and Mcl-1 down-regulation. In conclusion, the data suggest that protopine is a novel microtubule stabilizer with anticancer activity in HRPC cells through apoptotic pathway by modulating Cdk1 activity and Bcl-2 family of proteins.
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Affiliation(s)
- Chun-Han Chen
- Pharmacological Institute, College of Medicine, National Taiwan University, Taipei, ROC
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20
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Abstract
Background The appropriate control of mitotic entry and exit is reliant on a series of interlocking signaling events that coordinately drive the biological processes required for accurate cell division. Overlaid onto these signals that promote orchestrated cell division are checkpoints that ensure appropriate mitotic spindle formation, a lack of DNA damage, kinetochore attachment, and that each daughter cell has the appropriate complement of DNA. We recently discovered that AMP-activated protein kinase (AMPK) modulates the G2/M phase of cell cycle progression in part through its suppression of mammalian target of rapamycin (mTOR) signaling. AMPK directly phosphorylates the critical mTOR binding partner raptor inhibiting mTORC1 (mTOR-raptor rapamycin sensitive mTOR kinase complex 1). As mTOR has been previously tied to mitotic control, we examined further how raptor may contribute to this process. Methodology/Principal Findings We have discovered that raptor becomes highly phosphorylated in cells in mitosis. Utilizing tandem mass spectrometry, we identified a number of novel phosphorylation sites in raptor, and using phospho-specific antibodies demonstrated that raptor becomes phosphorylated on phospho-serine/threonine-proline sites in mitosis. A combination of site-directed mutagenesis in a tagged raptor cDNA and analysis with a series of new phospho-specific antibodies generated against different sites in raptor revealed that Serine 696 and Threonine 706 represent two key sites in raptor phosphorylated in mitosis. We demonstrate that the mitotic cyclin-dependent kinase cdc2/CDK1 is the kinase responsible for phosphorylating these sites, and its mitotic partner Cyclin B efficiently coimmunoprecipitates with raptor in mitotic cells. Conclusions/Significance This study demonstrates that the key mTOR binding partner raptor is directly phosphorylated during mitosis by cdc2. This reinforces previous studies suggesting that mTOR activity is highly regulated and important for mitotic progression, and points to a direct modulation of the mTORC1 complex during mitosis.
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21
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La Merrill M, Gordon RR, Hunter KW, Threadgill DW, Pomp D. Dietary fat alters pulmonary metastasis of mammary cancers through cancer autonomous and non-autonomous changes in gene expression. Clin Exp Metastasis 2010; 27:107-16. [PMID: 20151316 DOI: 10.1007/s10585-009-9302-7] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2009] [Accepted: 12/02/2009] [Indexed: 01/10/2023]
Abstract
Metastasis virulence, a significant contributor to breast cancer prognosis, is influenced by environmental factors like diet. We previously demonstrated in an F2 mouse population generated from a cross between the M16i polygenic obese and MMTV-PyMT mammary cancer models that high fat diet (HFD) decreases mammary cancer latency and increases pulmonary metastases compared to a matched control diet (MCD). Genetic analysis detected eight modifier loci for pulmonary metastasis, and diet significantly interacted with all eight loci. Here, gene expression microarray analysis was performed on mammary cancers from these mice. Despite the substantial dietary impact on metastasis and its interaction with metastasis modifiers, HFD significantly altered the expression of only five genes in mammary tumors; four of which, including serum amyloid A (Saa), are downstream of the tumor suppressor PTEN. Conversely, HFD altered the expression of 211 hepatic genes in a set of tumor free F2 control mice. Independent of diet, pulmonary metastasis virulence correlates with mammary tumor expression of genes involved in endocrine cancers, inflammation, angiogenesis, and invasion. The most significant virulence-associated network harbored genes also found in human adipose or mammary tissue, and contained upregulated Vegfa as a central node. Additionally, expression of Btn1a1, a gene physically located near a putative cis-acting eQTL on chromosome 13 and one of the metastasis modifiers, correlates with metastasis virulence. These data support the existence of diet-dependent and independent cancer modifier networks underlying differential susceptibility to mammary cancer metastasis and suggest that diet influences cancer metastasis virulence through tumor autonomous and non-autonomous mechanisms.
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Affiliation(s)
- Michele La Merrill
- Department of Preventive Medicine, Mount Sinai School of Medicine, Box 1057, New York, NY 10029, USA.
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22
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Williams BW, Chang JJ, Chi RM, Marker PH, Frethem CD, Le CT, Kratzke RA, Kirstein MN. Cap-dependent translation blockade and fixed dose-rate gemcitabine: interaction in an in vitro bioreactor system. Cancer Lett 2009; 284:37-46. [PMID: 19442436 DOI: 10.1016/j.canlet.2009.04.006] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2008] [Revised: 04/02/2009] [Accepted: 04/03/2009] [Indexed: 01/13/2023]
Abstract
Translation initiation commences with the binding of eIF-4F to the mRNA 5'-end cap. eIF-4F binds the cap structure via its eIF-4E subunit, which is the rate-limiting step for the initiation of translation. This pathway can be inhibited by 4E-binding proteins (4E-BPs). The present study investigated prolonged gemcitabine infusion in combination with reduced eIF-4E function on NSCLC cell viability in an in vitro bioreactor system. To assess attachment to the hollow fibers, cells with dominant active 4E-BP1 were first analyzed by scanning electron microscopy. Cells were treated with 0.5- or 2.5h (fixed dose rate) infusion (same total dose), simulating human plasma gemcitabine concentration-time profiles. An interaction was observed between fixed dose rate infusion gemcitabine and presence of dominant active 4E-BP1. We conclude that cap-dependent translation blockade and fixed dose rate infusion gemcitabine treatment results in a significant interaction affecting cell viability in vitro.
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Affiliation(s)
- Brent W Williams
- Department of Experimental and Clinical Pharmacology, College of Pharmacy and Comprehensive Cancer Center, University of Minnesota, 717 Delaware St. SE, Minneapolis, MN 55414, USA
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23
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Rapamycin differentially inhibits S6Ks and 4E-BP1 to mediate cell-type-specific repression of mRNA translation. Proc Natl Acad Sci U S A 2008; 105:17414-9. [PMID: 18955708 DOI: 10.1073/pnas.0809136105] [Citation(s) in RCA: 652] [Impact Index Per Article: 40.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
The mammalian translational initiation machinery is a tightly controlled system that is composed of eukaryotic initiation factors, and which controls the recruitment of ribosomes to mediate cap-dependent translation. Accordingly, the mTORC1 complex functionally controls this cap-dependent translation machinery through the phosphorylation of its downstream substrates 4E-BPs and S6Ks. It is generally accepted that rapamycin, a specific inhibitor of mTORC1, is a potent translational repressor. Here we report the unexpected discovery that rapamycin's ability to regulate cap-dependent translation varies significantly among cell types. We show that this effect is mechanistically caused by rapamycin's differential effect on 4E-BP1 versus S6Ks. While rapamycin potently inhibits S6K activity throughout the duration of treatment, 4E-BP1 recovers in phosphorylation within 6 h despite initial inhibition (1-3 h). This reemerged 4E-BP1 phosphorylation is rapamycin-resistant but still requires mTOR, Raptor, and mTORC1's activity. Therefore, these results explain how cap-dependent translation can be maintained in the presence of rapamycin. In addition, we have also defined the condition by which rapamycin can control cap-dependent translation in various cell types. Finally, we show that mTOR catalytic inhibitors are effective inhibitors of the rapamycin-resistant phenotype.
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24
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Armengol G, Rojo F, Castellví J, Iglesias C, Cuatrecasas M, Pons B, Baselga J, Ramón y Cajal S. 4E-binding protein 1: a key molecular "funnel factor" in human cancer with clinical implications. Cancer Res 2007; 67:7551-5. [PMID: 17699757 DOI: 10.1158/0008-5472.can-07-0881] [Citation(s) in RCA: 211] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
In an attempt to identify molecules that clearly reflect the oncogenic role of cell signaling pathways in human tumors, we propose a concept we term "funnel factor", a factor where several oncogenic signals converge and drive the proliferative signal downstream. In studies done in various tumor types, the expression of key cell signaling factors, including Her1 and Her2 growth factor receptors, as well as the RAS-RAF-mitogen-activated protein kinase and the phosphatidylinositol 3-kinase-AKT-mammalian target of rapamycin pathways was correlated with the associated clinicopathologic characteristics of these tumors. The downstream factors p70, S6, 4E-binding protein 1 (4E-BP1), and eukaryotic translation initiation factor 4E, which play a critical role in the control of protein synthesis, survival, and cell growth, were also analyzed. We found that phosphorylated 4E-BP1 (p-4E-BP1) expression in breast, ovary, and prostate tumors is associated with malignant progression and an adverse prognosis regardless of the upstream oncogenic alterations. Thus, p-4E-BP1 seems to act as a funnel factor for an essential oncogenic capability of tumor cells, self-sufficiency in growth signals, and could be a highly relevant molecular marker of malignant potential. Further investigation into this concept may identify additional funnel factors in the oncogenic pathways and provide potential therapeutic targets.
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Affiliation(s)
- Gemma Armengol
- Department of Pathology, Vall d'Hebron University Hospital, Barcelona, Spain
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25
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Tsuda N, Chang DZ, Mine T, Efferson C, García-Sastre A, Wang X, Ferrone S, Ioannides CG. Taxol Increases the Amount and T Cell–Activating Ability of Self-Immune Stimulatory Multimolecular Complexes Found in Ovarian Cancer Cells. Cancer Res 2007; 67:8378-87. [PMID: 17804754 DOI: 10.1158/0008-5472.can-07-0327] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
It has been proposed that chemotherapy enhances tumor antigen (TA)-specific immunity. The molecular form of TA from ovarian tumor that activates cellular immunity is unknown. We report here identification of a novel molecular form of immunogenic TA for CD8(+) cells named self-immune stimulatory multimolecular complexes (ISMMC). ISMMC consist of a molecular complex of polyosome/ribosome-bound ubiquitinated nascent HER-2 polypeptides. This complex is chaperoned by heat shock protein Gp96, which mediates ISMMC uptake by antigen-presenting cells through the scavenger receptor CD91. RNAs in ISMMC stimulate immature dendritic cells to secrete interleukin 12 and induce IFN-gamma in peripheral blood mononuclear cells. ISMMC dissociate, retrotranslocate from the lysosome to cytoplasm, and are processed to peptides by the proteasome. At subpharmacologic doses, Taxol increased the amount of ISMMC by three to four times and modified their composition by inducing the attachment of cochaperones of HSP70, such as the mitotic-phase phosphoprotein 11J. On a total protein basis, Taxol induced ISMMC, expanded more CD8(+) cells, activated more CD56(+) NKG2D(+) cells to produce IFN-gamma, and were more potent inducers of high T-cell receptor density Perforin(+) cells than native ISMMC and peptide E75. Elucidation of the composition of ISMMC and identification of adducts formed by Taxol should be important for developing molecular cancer vaccines.
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Affiliation(s)
- Naotake Tsuda
- Department of Gynecologic Oncology, The University of Texas M D Anderson Cancer Center, Houston, TX 77030, USA
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Darwiche N, El-Banna S, Gali-Muhtasib H. Cell cycle modulatory and apoptotic effects of plant-derived anticancer drugs in clinical use or development. Expert Opin Drug Discov 2007; 2:361-79. [DOI: 10.1517/17460441.2.3.361] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
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