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SHI HUAIPING, ZHANG TIANYING, YI YONGQING, MA YUE. Inhibition of the Ras-ERK pathway in mitotic COS7 cells is due to the inability of EGFR/Raf to transduce EGF signaling to downstream proteins. Oncol Rep 2016; 35:3593-9. [DOI: 10.3892/or.2016.4696] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2015] [Accepted: 02/03/2016] [Indexed: 11/05/2022] Open
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Shi H, Zhang T, Yi Y, Luo J. Investigation of MEK activity in COS7 cells entering mitosis. Mol Med Rep 2014; 10:3163-8. [PMID: 25269541 DOI: 10.3892/mmr.2014.2590] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2013] [Accepted: 05/19/2014] [Indexed: 11/05/2022] Open
Abstract
Although the mitogen-activated protein kinase (MAPK) pathway has been extensively investigated, numerous events remain unclear. In the present study, we examined mitogen-activated protein kinase kinase (MEK) expression from interphase to mitosis. Following nocodazole treatment, COS7 cells gradually became round as early as 4 h after treatment. Cyclin B1 expression gradually increased from 4 to 24 h in the presence of nocodazole. When cells were treated with nocodazole for 4 h, the level of epidermal growth factor (EGF)-mediated MEK phosphorylation did not significantly change between nocodazole-untreated and -treated (4 h) cells (P>0.05). However, EGF-mediated MEK phosphorylation was significantly inhibited upon treatment with nocodazole for 8 and 24 h compared to nocodazole-untreated cells (P<0.05). MEK phosphorylation levels were comparable between 1, 5, 10 and 50 ng/ml EGF treatments. Phorbol 12-myristic 13-acetate (PMA) did not activate MEK in mitotic cells. Following treatment of COS7 cells at the interphase with AG1478 or U0126, MEK phosphorylation was blocked. In addition, the investigation of the expression of proteins downstream of MEK demonstrated that EGF does not significantly affect the phosphorylation level of extracellular-signal-regulated kinase (ERK), ribosomal protein S6 kinase (RSK) and Elk in mitotic cells (P>0.05). The results showed that MEK expression is gradually inhibited from cell interphase to mitosis, and that MEK downstream signaling is affected by this inhibition, which probably reflects the requirements of cell physiology during mitosis.
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Affiliation(s)
- Huaiping Shi
- College of Animal Science and Technology, Northwest A&F University, Yangling, Shaanxi 712100, P.R. China
| | - Tianying Zhang
- College of Animal Science and Technology, Northwest A&F University, Yangling, Shaanxi 712100, P.R. China
| | - Yongqing Yi
- College of Animal Science and Technology, Northwest A&F University, Yangling, Shaanxi 712100, P.R. China
| | - Jun Luo
- College of Animal Science and Technology, Northwest A&F University, Yangling, Shaanxi 712100, P.R. China
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Pike T, Widberg C, Goodall A, Payne E, Giles N, Hancock J, Gabrielli B. Truncated MEK1 is required for transient activation of MAPK signalling in G2 phase cells. Cell Signal 2013; 25:1423-8. [DOI: 10.1016/j.cellsig.2013.03.014] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2013] [Accepted: 03/16/2013] [Indexed: 02/08/2023]
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Wang QQ, Zhang ZY, Xiao JY, Yi C, Li LZ, Huang Y, Yun JP. Knockdown of nucleophosmin induces S-phase arrest in HepG2 cells. CHINESE JOURNAL OF CANCER 2011; 30:853-60. [PMID: 22098949 PMCID: PMC4013333 DOI: 10.5732/cjc.011.10362] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Nucleophosmin/B23 (NPM) is a universally expressed nucleolar phosphoprotein that participates in proliferation, apoptosis, ribosome assembly, and centrosome duplication; however, the role of NPM in cell cycle regulation is not well characterized. We investigated the mechanism by which NPM is involved in cell cycle regulation. NPM was knocked down using siRNA in HepG2 hepatoblastoma cells. NPM translocation following actinomycin D (ActD) treatment was investigated using immunofluorescent staining. Expression of NPM and other factors involved in cell cycle regulation was examined by Western blotting. Cell cycle distribution was measured using flow cytometry to detect 5-ethynyl-2'-deoxyuridine (EdU) incorporation. Cell proliferation was quantified by the MTT assay. Knockdown of NPM increased the percentage of HepG2 cells in S phase and led to decreased expression of P53 and P21Cip1/WAF1. S-phase arrest in HepG2 cells was significantly enhanced by ActD treatment. Furthermore, knockdown of NPM abrogated ActD-induced G2/M phase cell cycle arrest. Taken together, these data demonstrate that inhibition of NPM has a significant effect on the cell cycle.
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Affiliation(s)
- Qing-Qing Wang
- Department of Pathology, Sun Yat-sen University Cancer Center, Guangzhou, Guangdong, People's Republic of China
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Chambard JC, Lefloch R, Pouysségur J, Lenormand P. ERK implication in cell cycle regulation. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2007; 1773:1299-310. [PMID: 17188374 DOI: 10.1016/j.bbamcr.2006.11.010] [Citation(s) in RCA: 553] [Impact Index Per Article: 32.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/11/2006] [Revised: 11/07/2006] [Accepted: 11/10/2006] [Indexed: 11/28/2022]
Abstract
The Ras/Raf/MEK/ERK signaling cascade that integrates an extreme variety of extracellular stimuli into key biological responses controlling cell proliferation, differentiation or death is one of the most studied intracellular pathways. Here we present some evidences that have been accumulated over the last 15 years proving the requirement of ERK in the control of cell proliferation. In this review we focus (i) on the spatio-temporal control of ERK signaling, (ii) on the key cellular components linking extracellular signals to the induction and activation of cell cycle events controlling G1 to S-phase transition and (iii) on the role of ERK in the growth factor-independent G2/M phase of the cell cycle. As ERK pathway is often co-activated with the PI3 kinase signaling, we highlight some of the key points of convergence leading to a full activation of mTOR via ERK and AKT synergies. Finally, ERK and AKT targets being constitutively activated in so many human cancers, we briefly touched the cure issue of using more specific drugs in rationally selected cancer patients.
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Affiliation(s)
- Jean-Claude Chambard
- Institute of Signaling Developmental Biology and Cancer, CNRS UMR 6543, Universite de Nice-Sofia Antipolis, Centre A. Lacassagne, 33 Avenue de Valombrose, 06189 Nice, France
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Meloche S, Pouysségur J. The ERK1/2 mitogen-activated protein kinase pathway as a master regulator of the G1- to S-phase transition. Oncogene 2007; 26:3227-39. [PMID: 17496918 DOI: 10.1038/sj.onc.1210414] [Citation(s) in RCA: 820] [Impact Index Per Article: 48.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The Ras-dependent extracellular signal-regulated kinase (ERK)1/2 mitogen-activated protein (MAP) kinase pathway plays a central role in cell proliferation control. In normal cells, sustained activation of ERK1/ERK2 is necessary for G1- to S-phase progression and is associated with induction of positive regulators of the cell cycle and inactivation of antiproliferative genes. In cells expressing activated Ras or Raf mutants, hyperactivation of the ERK1/2 pathway elicits cell cycle arrest by inducing the accumulation of cyclin-dependent kinase inhibitors. In this review, we discuss the mechanisms by which activated ERK1/ERK2 regulate growth and cell cycle progression of mammalian somatic cells. We also highlight the findings obtained from gene disruption studies.
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Affiliation(s)
- S Meloche
- Departments of Pharmacology and Molecular Biology, Institut de Recherche en Immunologie et Cancérologie, Université de Montréal, Montreal, Quebec, Canada.
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Feinstein TN, Linstedt AD. Mitogen-activated protein kinase kinase 1-dependent Golgi unlinking occurs in G2 phase and promotes the G2/M cell cycle transition. Mol Biol Cell 2006; 18:594-604. [PMID: 17182854 PMCID: PMC1783781 DOI: 10.1091/mbc.e06-06-0530] [Citation(s) in RCA: 82] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Two controversies have emerged regarding the signaling pathways that regulate Golgi disassembly at the G(2)/M cell cycle transition. The first controversy concerns the role of mitogen-activated protein kinase activator mitogen-activated protein kinase kinase (MEK)1, and the second controversy concerns the participation of Golgi structure in a novel cell cycle "checkpoint." A potential simultaneous resolution is suggested by the hypothesis that MEK1 triggers Golgi unlinking in late G(2) to control G(2)/M kinetics. Here, we show that inhibition of MEK1 by RNA interference or by using the MEK1/2-specific inhibitor U0126 delayed the passage of synchronized HeLa cells into M phase. The MEK1 requirement for normal mitotic entry was abrogated if Golgi proteins were dispersed before M phase by treatment of cells with brefeldin A or if GRASP65, which links Golgi stacks into a ribbon network, was depleted. Imaging revealed that unlinking of the Golgi apparatus begins before M phase, is independent of cyclin-dependent kinase 1 activation, and requires MEK signaling. Furthermore, expression of the GRASP family member GRASP55 after alanine substitution of its MEK1-dependent mitotic phosphorylation sites inhibited both late G(2) Golgi unlinking and the G(2)/M transition. Thus, MEK1 plays an in vivo role in Golgi reorganization, which regulates cell cycle progression.
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Affiliation(s)
- Timothy N. Feinstein
- Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, PA 15213
| | - Adam D. Linstedt
- Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, PA 15213
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Mogila V, Xia F, Li WX. An intrinsic cell cycle checkpoint pathway mediated by MEK and ERK in Drosophila. Dev Cell 2006; 11:575-82. [PMID: 17011495 PMCID: PMC3095892 DOI: 10.1016/j.devcel.2006.08.010] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2006] [Revised: 07/06/2006] [Accepted: 08/22/2006] [Indexed: 11/29/2022]
Abstract
Cell cycle checkpoints are surveillance mechanisms that safeguard genome integrity. While the extrinsic pathways that halt the cell cycle in response to DNA damages have been well documented, the intrinsic pathways that ensure orderly progression of cell cycle events are not well understood. We demonstrate that Drosophila MEK and ERK constitute an essential intrinsic checkpoint pathway that restrains cell cycle progression in the absence of DNA damage and also responds to ionizing radiation to arrest the cell cycle. Embryos lacking MEK exhibit faster and extra division cycles and fail to undergo timely midblastula transition (MBT) or arrest following ionizing radiation. Conversely, constitutively activated MEK causes cell cycle arrest. Further, MEK activation in the early embryo is cell cycle-dependent and Raf independent and increases in response to ionizing radiation or in the absence of Chk1. Thus, MEK/ERK activation is required for multiple checkpoints and is essential for orderly cell cycle progression.
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Affiliation(s)
- Vladic Mogila
- Department of Biomedical Genetics University of Rochester Medical Center Rochester, New York 14642
| | - Fan Xia
- Department of Biomedical Genetics University of Rochester Medical Center Rochester, New York 14642
| | - Willis X. Li
- Department of Biomedical Genetics University of Rochester Medical Center Rochester, New York 14642
- Correspondence:
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Shinohara M, Mikhailov AV, Aguirre-Ghiso JA, Rieder CL. Extracellular signal-regulated kinase 1/2 activity is not required in mammalian cells during late G2 for timely entry into or exit from mitosis. Mol Biol Cell 2006; 17:5227-40. [PMID: 17035635 PMCID: PMC1679686 DOI: 10.1091/mbc.e06-04-0284] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
Extracellular signal-regulated kinase (ERK)1/2 activity is reported to be required in mammalian cells for timely entry into and exit from mitosis (i.e., the G2-mitosis [G2/M] and metaphase-anaphase [M/A] transitions). However, it is unclear whether this involvement reflects a direct requirement for ERK1/2 activity during these transitions or for activating gene transcription programs at earlier stages of the cell cycle. To examine these possibilities, we followed live cells in which ERK1/2 activity was inhibited through late G2 and mitosis. We find that acute inhibition of ERK1/2 during late G2 and through mitosis does not affect the timing of the G2/M or M/A transitions in normal or transformed human cells, nor does it impede spindle assembly, inactivate the p38 stress-activated checkpoint during late G2 or the spindle assembly checkpoint during mitosis. Using CENP-F as a marker for progress through G2, we also show that sustained inhibition of ERK1/2 transiently delays the cell cycle in early/mid-G2 via a p53-dependent mechanism. Together, our data reveal that ERK1/2 activity is required in early G2 for a timely entry into mitosis but that it does not directly regulate cell cycle progression from late G2 through mitosis in normal or transformed mammalian cells.
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Affiliation(s)
- Mio Shinohara
- *Division of Molecular Medicine, Wadsworth Center, New York State Department of Health, Albany, NY 12201
- Department of Biomedical Sciences, School of Public Health, and
| | - Alexei V. Mikhailov
- *Division of Molecular Medicine, Wadsworth Center, New York State Department of Health, Albany, NY 12201
- Department of Biomedical Sciences, School of Public Health, and
| | - Julio A. Aguirre-Ghiso
- Department of Biomedical Sciences, School of Public Health, and
- Gen*NY*Sis Center for Excellence in Cancer Genomics, State University of New York, Albany, NY 12144; and
| | - Conly L. Rieder
- *Division of Molecular Medicine, Wadsworth Center, New York State Department of Health, Albany, NY 12201
- Department of Biomedical Sciences, School of Public Health, and
- Marine Biology Laboratory, Woods Hole, MA 02543
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Bergstralh DT, Conti BJ, Moore CB, Brickey WJ, Taxman DJ, Ting JPY. Global functional analysis of nucleophosmin in Taxol response, cancer, chromatin regulation, and ribosomal DNA transcription. Exp Cell Res 2006; 313:65-76. [PMID: 17069796 PMCID: PMC1805482 DOI: 10.1016/j.yexcr.2006.09.016] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2006] [Revised: 09/14/2006] [Accepted: 09/18/2006] [Indexed: 11/28/2022]
Abstract
Analysis of lung cancer response to chemotherapeutic agents showed the accumulation of a Taxol-induced protein that reacted with an anti-phospho-MEK1/2 antibody. Mass spectroscopy identified the protein as nucleophosmin/B23 (NPM), a multifunctional protein with diverse roles: ribosome biosynthesis, p53 regulation, nuclear-cytoplasmic shuttling, and centrosome duplication. Our work demonstrates that following cellular exposure to mitosis-arresting agents, NPM is phosphorylated and its chromatographic property is altered, suggesting changes in function during mitosis. To determine the functional relevance of NPM, its expression in tumor cells was reduced by siRNA. Cells with reduced NPM were treated with Taxol followed by microarray profiling accompanied by gene/protein pathway analyses. These studies demonstrate several expected and unexpected consequences of NPM depletion. The predominant downstream effectors of NPM are genes involved in cell proliferation, cancer, and the cell cycle. In congruence with its role in cancer, NPM is over-expressed in primary malignant lung cancer tissues. We also demonstrate a role for NPM in the expression of genes encoding SET (TAF1beta) and the histone methylase SET8. Additionally, we show that NPM is required for a previously unobserved G2/M upregulation of TAF1A, which encodes the rDNA transcription factor TAF(I)48. These results demonstrate multi-faceted functions of NPM that can affect cancer cells.
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Affiliation(s)
- Daniel T Bergstralh
- Curriculum in Genetics and Molecular Biology, Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA.
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