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Novák B, Tyson JJ. The bistable mitotic switch in fission yeast. Mol Biol Cell 2024; 35:ar77. [PMID: 38598296 DOI: 10.1091/mbc.e24-03-0142] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/12/2024] Open
Abstract
In favorable conditions, eukaryotic cells proceed irreversibly through the cell division cycle (G1-S-G2-M) in order to produce two daughter cells with the same number and identity of chromosomes of their progenitor. The integrity of this process is maintained by "checkpoints" that hold a cell at particular transition points of the cycle until all requisite events are completed. The crucial functions of these checkpoints seem to depend on irreversible bistability of the underlying checkpoint control systems. Bistability of cell cycle transitions has been confirmed experimentally in frog egg extracts, budding yeast cells and mammalian cells. For fission yeast cells, a recent paper by Patterson et al. (2021) provides experimental evidence for an abrupt transition from G2 phase into mitosis, and we show that these data are consistent with a stochastic model of a bistable switch governing the G2/M checkpoint. Interestingly, our model suggests that their experimental data could also be explained by a reversible/sigmoidal switch, and stochastic simulations confirm this supposition. We propose a simple modification of their experimental protocol that could provide convincing evidence for (or against) bistability of the G2/M transition in fission yeast.
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Affiliation(s)
- Béla Novák
- Department of Biochemistry, Oxford University, Oxford OX1 3QU, UK
| | - John J Tyson
- Department of Biological Sciences, Virginia Polytechnic Institute & State University, Blacksburg, VA 24061
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Mironov AA, Beznoussenko GV. Opinion: On the Way towards the New Paradigm of Atherosclerosis. Int J Mol Sci 2022; 23:ijms23042152. [PMID: 35216269 PMCID: PMC8879789 DOI: 10.3390/ijms23042152] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2021] [Revised: 02/11/2022] [Accepted: 02/11/2022] [Indexed: 02/07/2023] Open
Abstract
Atherosclerosis is a multicausal disease characterized by the formation of cholesterol-containing plaque in the pronounced intima nearest to the heart's elastic-type arteries that have high levels of blood circulation. Plaques are formed due to arterial pressure-induced damage to the endothelium in areas of turbulent blood flow. It is found in the majority of the Western population, including young people. This denies the monogenic mechanism of atherogenesis. In 1988, Orekhov et al. and Kawai et al. discovered that the presence of atherogenic (modified, including oxidized ones) LDLs is necessary for atherogenesis. On the basis of our discovery, suggesting that the overloading of enterocytes with lipids could lead to the formation of modified LDLs, we proposed a new hypothesis explaining the main factors of atherogenesis. Indeed, when endothelial cells are damaged and then pass through the G2 phase of their cell cycle they secrete proteins into their basement membrane. This leads to thickening of the basement membrane and increases its affinity to LDL especially for modified ones. When the enterocyte transcytosis pathway is overloaded with fat, very large chylomicrons are formed, which have few sialic acids, circulate in the blood for a long time, undergo oxidation, and can induce the production of autoantibodies. It is the sialic acids that shield the short forks of the polysaccharide chains to which autoantibodies are produced. Here, these data are evaluated from the point of view of our new model.
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Pal A, Sengupta S, Kundu R. Tiliacora racemosa leaves induce oxidative stress mediated DNA damage leading to G2/M phase arrest and apoptosis in cervical cancer cells SiHa. J Ethnopharmacol 2021; 269:113686. [PMID: 33309918 DOI: 10.1016/j.jep.2020.113686] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/20/2020] [Revised: 12/03/2020] [Accepted: 12/07/2020] [Indexed: 06/12/2023]
Abstract
ETHNOPHARMACOLOGICAL RELEVANCE The Menispermaceae plant Tiliacora racemosa is immensely popular in Indian traditional Ayurvedic medicine as "Krishnavetra" for its remarkable anti-cancerous property, and is commonly used by tribal population for the treatment of skin infections, snake bites and filariasis. AIM OF THE STUDY This present study intends to identify the modus operandi behind the cytotoxic activity of Tiliacora racemosa leaves in cervical cancer cells SiHa. Focus has been instilled in the ability of the plant extract to target multiple signaling pathways leading to cell cycle arrest and cell death in SiHa cells, followed by a pharmacological characterization to identify the bioactive principle. MATERIALS AND METHODS T. racemosa leaves extracted in methanol, ethyl acetate, hexane and aqueous solvent were screened for cytotoxicity in HeLa, SiHa, C33A (cervical cancer cells) and HEK cells by MTT assay. SiHa cells were treated with the most potent extract (TRM). Cellular morphology, clonogenic and wound healing potential, presence of intracellular ROS and NO, lipid peroxidation, activity of cellular antioxidants (SOD, CAT, GSH), DNA damage detection by comet assay and localisation of γ-H2AX foci, intracellular expression of PARP-1, Bax/Bcl2 and caspase-3, loss in mitochondrial membrane potential by JC1 (flow cytometry) and Rh123 (microscopy), cell cycle analysis, Annexin-FITC assay, AO/EtBr microscopy and apoptotic proteome profiling were undertaken in the treated cells. All the related proteins were studied by immunoblots. Effect of NAC (ROS-scavenger) on cell viability, DNA damage and apoptosis were studied. Phytochemical characterization of all TR extracts was followed by LC-MS analysis of TRM and isolated alkaloid of TR was assessed for cytotoxicity. RESULTS The methanol extract of T. racemosa (TRM) rich in bisbenzylisoquinoline and other alkaloids impeded the proliferation of cervical cancer cells SiHa in vitro through disruption of cellular redox homeostasis caused by increase in cellular ROS and NO with concomitant decrease in the cellular antioxidants. Double-stranded DNA damage was noted from γH2AX foci accumulation and Parp-1 activation leading to ATM-Chk2-p53 pathway arresting the cells at G2/M-phase through cyclin B1 inhibition. The mitochondrial membrane potential was also disturbed leading to caspase-3 dependent apoptotic induction by both extrinsic and intrinsic pathway. Immunoblots show TRM also inhibited PI3K/Akt and NFκB pathway. NAC pre-treatment rescued the cell viability proving DNA damage and apoptosis to be direct consequences of ROS overproduction. Lastly, the therapeutic potential of T. racemosa is was hypothesized to be possibly derived from its alkaloid content. CONCLUSION This study proves the age old ethnnopharmacological anticancer role of T. racemosa. The leaf extracts inhibited the anomalous proliferation of SiHa cells by virtue of G2/M-phase cell cycle arrest and apoptotic cell death. Oxidative stress mediated double stranded DNA damage paved the way towards apoptotic cell death through multiple routes, including PI3K/Akt/NFκB pathway. The abundant alkaloid content of T. racemosa was denoted as the probable responsible cytotoxic principle.
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Affiliation(s)
- Asmita Pal
- Cell Biology Laboratory, Department of Botany, University of Calcutta, 35, Ballygunge Circular Road, Kolkata, 700019, India
| | - Soumee Sengupta
- Cell Biology Laboratory, Department of Botany, University of Calcutta, 35, Ballygunge Circular Road, Kolkata, 700019, India
| | - Rita Kundu
- Cell Biology Laboratory, Department of Botany, University of Calcutta, 35, Ballygunge Circular Road, Kolkata, 700019, India.
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Otsuki L, Brand AH. Dorsal-Ventral Differences in Neural Stem Cell Quiescence Are Induced by p57 KIP2/Dacapo. Dev Cell 2019; 49:293-300.e3. [PMID: 30905769 PMCID: PMC6486397 DOI: 10.1016/j.devcel.2019.02.015] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2018] [Revised: 01/28/2019] [Accepted: 02/15/2019] [Indexed: 12/27/2022]
Abstract
Quiescent neural stem cells (NSCs) in the adult brain are regenerative cells that could be activated therapeutically to repair damage. It is becoming apparent that quiescent NSCs exhibit heterogeneity in their propensity for activation and in the progeny that they generate. We discovered recently that NSCs undergo quiescence in either G0 or G2 in the Drosophila brain, challenging the notion that all quiescent stem cells are G0 arrested. We found that G2-quiescent NSCs become activated prior to G0 NSCs. Here, we show that the cyclin-dependent kinase inhibitor Dacapo (Dap; ortholog of p57KIP2) determines whether NSCs enter G0 or G2 quiescence during embryogenesis. We demonstrate that the dorsal patterning factor, Muscle segment homeobox (Msh; ortholog of MSX1/2/3) binds directly to the Dap locus and induces Dap expression in dorsal NSCs, resulting in G0 arrest, while more ventral NSCs undergo G2 quiescence. Our results reveal region-specific regulation of stem cell quiescence. p57/Dap determines whether neural stem cells enter G0 quiescence or G2 quiescence The dorsal patterning factor MSX/Msh promotes p57/Dap expression and G0 quiescence Ventral stem cells instead express NKX/Vnd and undergo G2 quiescence Stem cells undergo distinct types of quiescence depending on axial identity
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Affiliation(s)
- Leo Otsuki
- The Gurdon Institute and Department of Physiology, Development and Neuroscience, University of Cambridge, Tennis Court Road, Cambridge CB2 1QN, UK
| | - Andrea H Brand
- The Gurdon Institute and Department of Physiology, Development and Neuroscience, University of Cambridge, Tennis Court Road, Cambridge CB2 1QN, UK.
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Halim VA, García-Santisteban I, Warmerdam DO, van den Broek B, Heck AJR, Mohammed S, Medema RH. Doxorubicin-induced DNA Damage Causes Extensive Ubiquitination of Ribosomal Proteins Associated with a Decrease in Protein Translation. Mol Cell Proteomics 2018; 17:2297-2308. [PMID: 29438997 PMCID: PMC6283304 DOI: 10.1074/mcp.ra118.000652] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2018] [Indexed: 11/06/2022] Open
Abstract
Protein posttranslational modifications (PTMs) play a central role in the DNA damage response. In particular, protein phosphorylation and ubiquitination have been shown to be essential in the signaling cascade that coordinates break repair with cell cycle progression. Here, we performed whole-cell quantitative proteomics to identify global changes in protein ubiquitination that are induced by DNA double-strand breaks. In total, we quantified more than 9,400 ubiquitin sites and found that the relative abundance of ∼10% of these sites was altered in response to DNA double-strand breaks. Interestingly, a large proportion of ribosomal proteins, including those from the 40S as well as the 60S subunit, were ubiquitinated in response to DNA damage. In parallel, we discovered that DNA damage leads to the inhibition of ribosome function. Taken together, these data uncover the ribosome as a major target of the DNA damage response.
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Affiliation(s)
- Vincentius A Halim
- Biomolecular Mass Spectrometry and Proteomics Group, Bijvoet Center for Biomolecular Research and Utrecht Institute for Pharmaceutical Sciences, Utrecht University, 3584 CH Utrecht, The Netherlands; Netherlands Proteomics Centre, 3584 CH Utrecht, The Netherlands; Division of Cell Biology and Cancer Genomics Center, Netherlands Cancer Institute, 1066 CX Amsterdam, The Netherlands
| | - Iraia García-Santisteban
- Division of Cell Biology and Cancer Genomics Center, Netherlands Cancer Institute, 1066 CX Amsterdam, The Netherlands; Department of Genetics, Physical Anthropology and Animal Physiology, University of the Basque Country (UPV/EHU), Leioa, Spain
| | - Daniel O Warmerdam
- Division of Cell Biology and Cancer Genomics Center, Netherlands Cancer Institute, 1066 CX Amsterdam, The Netherlands; European Research Institute for the Biology of Ageing, University Medical Center Groningen, 9713 AV Groningen, The Netherlands
| | - Bram van den Broek
- Division of Cell Biology and Cancer Genomics Center, Netherlands Cancer Institute, 1066 CX Amsterdam, The Netherlands
| | - Albert J R Heck
- Biomolecular Mass Spectrometry and Proteomics Group, Bijvoet Center for Biomolecular Research and Utrecht Institute for Pharmaceutical Sciences, Utrecht University, 3584 CH Utrecht, The Netherlands; Netherlands Proteomics Centre, 3584 CH Utrecht, The Netherlands
| | - Shabaz Mohammed
- Biomolecular Mass Spectrometry and Proteomics Group, Bijvoet Center for Biomolecular Research and Utrecht Institute for Pharmaceutical Sciences, Utrecht University, 3584 CH Utrecht, The Netherlands; Netherlands Proteomics Centre, 3584 CH Utrecht, The Netherlands; Department of Biochemistry, University of Oxford, OX13TA Oxford, United Kingdom; Chemistry Research Laboratory, Department of Chemistry, University of Oxford, OX13TA Oxford, United Kingdom
| | - René H Medema
- Division of Cell Biology and Cancer Genomics Center, Netherlands Cancer Institute, 1066 CX Amsterdam, The Netherlands.
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Kapuy O, Vinod PK, Bánhegyi G, Novák B. Systems-level feedback regulation of cell cycle transitions in Ostreococcus tauri. Plant Physiol Biochem 2018; 126:39-46. [PMID: 29499434 DOI: 10.1016/j.plaphy.2018.02.010] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/23/2017] [Revised: 02/08/2018] [Accepted: 02/10/2018] [Indexed: 06/08/2023]
Abstract
Ostreococcus tauri is the smallest free-living unicellular organism with one copy of each core cell cycle genes in its genome. There is a growing interest in this green algae due to its evolutionary origin. Since O. tauri is diverged early in the green lineage, relatively close to the ancestral eukaryotic cell, it might hold a key phylogenetic position in the eukaryotic tree of life. In this study, we focus on the regulatory network of its cell division cycle. We propose a mathematical modelling framework to integrate the existing knowledge of cell cycle network of O. tauri. We observe that feedback loop regulation of both G1/S and G2/M transitions in O. tauri is conserved, which can make the transition bistable. This is essential to make the transition irreversible as shown in other eukaryotic organisms. By performing sequence analysis, we also predict the presence of the Greatwall/PP2A pathway in the cell cycle of O. tauri. Since O. tauri cell cycle machinery is conserved, the exploration of the dynamical characteristic of the cell division cycle will help in further understanding the regulation of cell cycle in higher eukaryotes.
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Affiliation(s)
- Orsolya Kapuy
- Semmelweis University, Department of Medical Chemistry, Molecular Biology and Pathobiochemistry, Budapest, Hungary.
| | - P K Vinod
- Centre for Computational Natural Sciences and Bioinformatics, International Institute of Information Technology, Hyderabad, India
| | - Gábor Bánhegyi
- Semmelweis University, Department of Medical Chemistry, Molecular Biology and Pathobiochemistry, Budapest, Hungary
| | - Béla Novák
- University of Oxford, Oxford Centre for Integrative Systems Biology, Oxford, United Kingdom
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Shi Y, Guo S, Wang Y, Liu X, Li Q, Li T. Lamprey Prohibitin2 Arrest G2/M Phase Transition of HeLa Cells through Down-regulating Expression and Phosphorylation Level of Cell Cycle Proteins. Sci Rep 2018; 8:3932. [PMID: 29500418 PMCID: PMC5834496 DOI: 10.1038/s41598-018-22212-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2017] [Accepted: 02/20/2018] [Indexed: 01/13/2023] Open
Abstract
Prohibitin 2(PHB2) is a member of the SFPH trans-membrane family proteins. It is a highly conserved and functionally diverse protein that plays an important role in preserving the structure and function of the mitochondria. In this study, the lamprey PHB2 gene was expressed in HeLa cells to investigate its effect on cell proliferation. The effect of Lm-PHB2 on the proliferation of HeLa cells was determined by treating the cells with pure Lm-PHB2 protein followed by MTT assay. Using the synchronization method with APC-BrdU and PI double staining revealed rLm-PHB2 treatment induced the decrease of both S phase and G0/G1 phase and then increase of G2/M phase. Similarly, cells transfected with pEGFP-N1-Lm-PHB2 also exhibited remarkable reduction in proliferation. Western blot and quantitative real-time PCR(qRT-PCR) assays suggested that Lm-PHB2 caused cell cycle arrest in HeLa cells through inhibition of CDC25C and CCNB1 expression. According to our western blot analysis, Lm-PHB2 was also found to reduce the expression level of Wee1 and PLK1 and the phosphorylation level of CCNB1, CDC25C and CDK1 in HeLa cells. Lamprey prohibitin 2 could arrest G2/M phase transition of HeLa cells through down-regulating expression and phosphorylation level of cell cycle proteins.
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Affiliation(s)
- Ying Shi
- College of Life Sciences, Lamprey Research Center, Liaoning Provincial Key Laboratory of Biotechnology and Drug discovery, Liaoning Normal University, Dalian, 116081, China
| | - Sicheng Guo
- College of Life Sciences, Lamprey Research Center, Liaoning Provincial Key Laboratory of Biotechnology and Drug discovery, Liaoning Normal University, Dalian, 116081, China
| | - Ying Wang
- 210th Hospital of PLA, Dalian, 116011, China
| | - Xin Liu
- College of Life Sciences, Lamprey Research Center, Liaoning Provincial Key Laboratory of Biotechnology and Drug discovery, Liaoning Normal University, Dalian, 116081, China
| | - Qingwei Li
- College of Life Sciences, Lamprey Research Center, Liaoning Provincial Key Laboratory of Biotechnology and Drug discovery, Liaoning Normal University, Dalian, 116081, China.
| | - Tiesong Li
- College of Life Sciences, Lamprey Research Center, Liaoning Provincial Key Laboratory of Biotechnology and Drug discovery, Liaoning Normal University, Dalian, 116081, China.
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Abstract
This chapter describes a microfluidic device that enables immobilization and culturing of single rod-shaped S. pombe cells in a stand-up mode. The wide-band electrical impedance spectroscopy (EIS) has been integrated in the microfluidic device to continuously measure cell growth of single S. pombe cells. Cell growth curves showing cellular and intracellular features at high spatiotemporal resolution can be obtained from EIS signals. The features include longitudinal cell elongation in the G2 phase, mitosis, and cell division during an entire cell cycle of S. pombe cells. Microfluidics-based EIS systems provide, hence, a tool for dynamic single-cell studies.
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Affiliation(s)
- Zhen Zhu
- Southeast University, Key Laboratory of MEMS of Ministry of Education, Nanjing, China.
| | - Olivier Frey
- Department of Biosystems Science and Engineering, ETH Zurich, Basel, Switzerland
| | - Andreas Hierlemann
- Department of Biosystems Science and Engineering, ETH Zurich, Basel, Switzerland
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Bártová E, Suchánková J, Legartová S, Malyšková B, Hornáček M, Skalníková M, Mašata M, Raška I, Kozubek S. PCNA is recruited to irradiated chromatin in late S-phase and is most pronounced in G2 phase of the cell cycle. Protoplasma 2017; 254:2035-2043. [PMID: 28168519 DOI: 10.1007/s00709-017-1076-1] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/21/2016] [Accepted: 01/09/2017] [Indexed: 06/06/2023]
Abstract
DNA repair is a complex process that prevents genomic instability. Many proteins play fundamental roles in regulating the optimal repair of DNA lesions. Proliferating cell nuclear antigen (PCNA) is a key factor that initiates recombination-associated DNA synthesis after injury. Here, in very early S-phase, we show that the fluorescence intensity of mCherry-tagged PCNA after local micro-irradiation was less than the fluorescence intensity of non-irradiated mCherry-PCNA-positive replication foci. However, PCNA protein accumulated at locally irradiated chromatin in very late S-phase of the cell cycle, and this effect was more pronounced in the following G2 phase. In comparison to the dispersed form of PCNA, a reduced mobile fraction appeared in PCNA-positive replication foci during S-phase, and we observed similar recovery time after photobleaching at locally induced DNA lesions. This diffusion of mCherry-PCNA in micro-irradiated regions was not affected by cell cycle phases. We also studied the link between function of PCNA and A-type lamins in late S-phase. We found that the accumulation of PCNA at micro-irradiated chromatin is identical in wild-type and A-type lamin-deficient cells. Only micro-irradiation of the nuclear interior, and thus the irradiation of internal A-type lamins, caused the fluorescence intensity of mCherry-tagged PCNA to increase. In summary, we showed that PCNA begins to play a role in DNA repair in late S-phase and that PCNA function in repair is maintained during the G2 phase of the cell cycle. However, PCNA mobility is reduced after local micro-irradiation regardless of the cell cycle phase.
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Affiliation(s)
- Eva Bártová
- Institute of Biophysics, Academy of Sciences of the Czech Republic, v.v.i., Královopolská 135, 612 65, Brno, Czech Republic.
| | - Jana Suchánková
- Institute of Biophysics, Academy of Sciences of the Czech Republic, v.v.i., Královopolská 135, 612 65, Brno, Czech Republic
| | - Soňa Legartová
- Institute of Biophysics, Academy of Sciences of the Czech Republic, v.v.i., Královopolská 135, 612 65, Brno, Czech Republic
| | - Barbora Malyšková
- Institute of Biophysics, Academy of Sciences of the Czech Republic, v.v.i., Královopolská 135, 612 65, Brno, Czech Republic
| | - Matúš Hornáček
- Institute of Cellular Biology and Pathology, the First Faculty of Medicine, Charles University in Prague, Albertov 4, 128 01, Prague, Czech Republic
| | - Magdalena Skalníková
- Institute of Cellular Biology and Pathology, the First Faculty of Medicine, Charles University in Prague, Albertov 4, 128 01, Prague, Czech Republic
| | - Martin Mašata
- Institute of Cellular Biology and Pathology, the First Faculty of Medicine, Charles University in Prague, Albertov 4, 128 01, Prague, Czech Republic
| | - Ivan Raška
- Institute of Cellular Biology and Pathology, the First Faculty of Medicine, Charles University in Prague, Albertov 4, 128 01, Prague, Czech Republic
| | - Stanislav Kozubek
- Institute of Biophysics, Academy of Sciences of the Czech Republic, v.v.i., Královopolská 135, 612 65, Brno, Czech Republic
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Gheghiani L, Loew D, Lombard B, Mansfeld J, Gavet O. PLK1 Activation in Late G2 Sets Up Commitment to Mitosis. Cell Rep 2017; 19:2060-2073. [PMID: 28591578 DOI: 10.1016/j.celrep.2017.05.031] [Citation(s) in RCA: 123] [Impact Index Per Article: 17.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2016] [Revised: 04/08/2017] [Accepted: 05/09/2017] [Indexed: 11/15/2022] Open
Abstract
Commitment to mitosis must be tightly coordinated with DNA replication to preserve genome integrity. While we have previously established that the timely activation of CyclinB1-Cdk1 in late G2 triggers mitotic entry, the upstream regulatory mechanisms remain unclear. Here, we report that Polo-like kinase 1 (Plk1) is required for entry into mitosis during an unperturbed cell cycle and is rapidly activated shortly before CyclinB1-Cdk1. We determine that Plk1 associates with the Cdc25C1 phosphatase and induces its phosphorylation before mitotic entry. Plk1-dependent Cdc25C1 phosphosites are sufficient to promote mitotic entry, even when Plk1 activity is inhibited. Furthermore, we find that activation of Plk1 during G2 relies on CyclinA2-Cdk activity levels. Our findings thus elucidate a critical role for Plk1 in CyclinB1-Cdk1 activation and mitotic entry and outline how CyclinA2-Cdk, an S-promoting factor, poises cells for commitment to mitosis.
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Affiliation(s)
- Lilia Gheghiani
- Sorbonne Universités, UPMC University Paris 06, UFR927, 75005 Paris, France; CNRS UMR 8200, 94805 Villejuif, France; Gustave Roussy Cancer Campus, 94805 Villejuif, France
| | - Damarys Loew
- Institut Curie, PSL Research University, LSMP, 75248 Paris, France
| | | | - Jörg Mansfeld
- Cell Cycle, Biotechnology Center, Technische Universität Dresden, 01307 Dresden, Germany
| | - Olivier Gavet
- Sorbonne Universités, UPMC University Paris 06, UFR927, 75005 Paris, France; CNRS UMR 8200, 94805 Villejuif, France; Gustave Roussy Cancer Campus, 94805 Villejuif, France.
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Zhang B, Wang G, Xu X, Yang S, Zhuang T, Wang G, Ren H, Cheng SY, Jiang Q, Zhang C. DAZ-interacting Protein 1 (Dzip1) Phosphorylation by Polo-like Kinase 1 (Plk1) Regulates the Centriolar Satellite Localization of the BBSome Protein during the Cell Cycle. J Biol Chem 2017; 292:1351-1360. [PMID: 27979967 PMCID: PMC5270478 DOI: 10.1074/jbc.m116.765438] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2016] [Revised: 12/13/2016] [Indexed: 12/29/2022] Open
Abstract
The function of the primary cilia, which is assembled in most vertebrate cells, is achieved by transport in and out of kinds of signaling receptors. The BBSome protein complex could recognize and target membrane proteins to the cilia, but how the BBSome itself is transported into the cilia is poorly understood. Here we demonstrate that the centrosome protein Dzip1 mediates the assembly of the BBSome-Dzip1-PCM1 complex in the centriolar satellites (CS) at the G0 phase for ciliary translocation of the BBSome. Phosphorylation of Dzip1 at Ser-210 by Plk1 (polo-like kinase 1) during the G2 phase promotes disassembly of this complex, resulting in removal of Dzip1 and the BBSome from the CS. Inhibiting the kinase activity of Plk1 maintains the CS localization of the BBSome and Dzip1 at the G2 phase. Collectively, our findings reveal the cell cycle-dependent regulation of BBSome transport to the CS and highlight a potential mechanism that the BBSome-mediated signaling pathways are accordingly regulated during the cell cycle.
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Affiliation(s)
- Boyan Zhang
- From the Key Laboratory of Cell Proliferation and Differentiation of the Ministry of Education and the State Key Laboratory of Membrane Biology, College of Life Sciences, Peking University, Beijing 100871 and
| | - Gang Wang
- From the Key Laboratory of Cell Proliferation and Differentiation of the Ministry of Education and the State Key Laboratory of Membrane Biology, College of Life Sciences, Peking University, Beijing 100871 and
| | - Xiaowei Xu
- From the Key Laboratory of Cell Proliferation and Differentiation of the Ministry of Education and the State Key Laboratory of Membrane Biology, College of Life Sciences, Peking University, Beijing 100871 and
| | - Sisi Yang
- From the Key Laboratory of Cell Proliferation and Differentiation of the Ministry of Education and the State Key Laboratory of Membrane Biology, College of Life Sciences, Peking University, Beijing 100871 and
| | - Tenghan Zhuang
- From the Key Laboratory of Cell Proliferation and Differentiation of the Ministry of Education and the State Key Laboratory of Membrane Biology, College of Life Sciences, Peking University, Beijing 100871 and
| | - Guopeng Wang
- From the Key Laboratory of Cell Proliferation and Differentiation of the Ministry of Education and the State Key Laboratory of Membrane Biology, College of Life Sciences, Peking University, Beijing 100871 and
| | - He Ren
- From the Key Laboratory of Cell Proliferation and Differentiation of the Ministry of Education and the State Key Laboratory of Membrane Biology, College of Life Sciences, Peking University, Beijing 100871 and
| | - Steven Y Cheng
- the Department of Developmental Genetics, School of Basic Medical Sciences, Nanjing Medical University, Nanjing 210029, China
| | - Qing Jiang
- From the Key Laboratory of Cell Proliferation and Differentiation of the Ministry of Education and the State Key Laboratory of Membrane Biology, College of Life Sciences, Peking University, Beijing 100871 and
| | - Chuanmao Zhang
- From the Key Laboratory of Cell Proliferation and Differentiation of the Ministry of Education and the State Key Laboratory of Membrane Biology, College of Life Sciences, Peking University, Beijing 100871 and
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Bajar BT, Lam AJ, Badiee RK, Oh YH, Chu J, Zhou XX, Kim N, Kim BB, Chung M, Yablonovitch AL, Cruz BF, Kulalert K, Tao JJ, Meyer T, Su XD, Lin MZ. Fluorescent indicators for simultaneous reporting of all four cell cycle phases. Nat Methods 2016; 13:993-996. [PMID: 27798610 PMCID: PMC5548384 DOI: 10.1038/nmeth.4045] [Citation(s) in RCA: 121] [Impact Index Per Article: 15.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2016] [Accepted: 09/21/2016] [Indexed: 12/23/2022]
Abstract
A robust method for simultaneous visualization of all four cell cycle phases in living cells is highly desirable. We developed an intensiometric reporter of the transition from S to G2 phase and engineered a far-red fluorescent protein, mMaroon1, to visualize chromatin condensation in mitosis. We combined these new reporters with the previously described Fucci system to create Fucci4, a set of four orthogonal fluorescent indicators that together resolve all cell cycle phases.
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Affiliation(s)
- Bryce T Bajar
- Department of Bioengineering, Stanford University, Stanford, California, USA
- Department of Pediatrics, Stanford University, Stanford, California, USA
- School of Life Sciences, Peking University, Beijing, China
| | - Amy J Lam
- Department of Bioengineering, Stanford University, Stanford, California, USA
- Department of Pediatrics, Stanford University, Stanford, California, USA
| | - Ryan K Badiee
- Department of Biological Sciences, Stanford University, Stanford, California, USA
| | - Young-Hee Oh
- Department of Bioengineering, Stanford University, Stanford, California, USA
- Department of Pediatrics, Stanford University, Stanford, California, USA
- Department of Neurobiology, Stanford University, Stanford, California, USA
| | - Jun Chu
- Department of Bioengineering, Stanford University, Stanford, California, USA
- Department of Pediatrics, Stanford University, Stanford, California, USA
| | - Xin X Zhou
- Department of Bioengineering, Stanford University, Stanford, California, USA
- Department of Pediatrics, Stanford University, Stanford, California, USA
- Department of Neurobiology, Stanford University, Stanford, California, USA
| | - Namdoo Kim
- Department of Bioengineering, Stanford University, Stanford, California, USA
- Department of Pediatrics, Stanford University, Stanford, California, USA
- Department of Neurobiology, Stanford University, Stanford, California, USA
| | - Benjamin B Kim
- Department of Bioengineering, Stanford University, Stanford, California, USA
- Department of Pediatrics, Stanford University, Stanford, California, USA
- Department of Neurobiology, Stanford University, Stanford, California, USA
| | - Mingyu Chung
- Department of Chemical and Systems Biology, Stanford University, Stanford, California, USA
| | | | - Barney F Cruz
- Department of Chemistry, Stanford University, Stanford, California, USA
| | - Kanokwan Kulalert
- Department of Chemical Engineering, Stanford University, Stanford, California, USA
| | - Jacqueline J Tao
- Department of Bioengineering, Stanford University, Stanford, California, USA
| | - Tobias Meyer
- Department of Chemical and Systems Biology, Stanford University, Stanford, California, USA
| | - Xiao-Dong Su
- School of Life Sciences, Peking University, Beijing, China
| | - Michael Z Lin
- Department of Bioengineering, Stanford University, Stanford, California, USA
- Department of Pediatrics, Stanford University, Stanford, California, USA
- Department of Neurobiology, Stanford University, Stanford, California, USA
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13
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Mickelson-Young L, Wear E, Mulvaney P, Lee TJ, Szymanski ES, Allen G, Hanley-Bowdoin L, Thompson W. A flow cytometric method for estimating S-phase duration in plants. J Exp Bot 2016; 67:6077-6087. [PMID: 27697785 PMCID: PMC5100020 DOI: 10.1093/jxb/erw367] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
The duration of the DNA synthesis stage (S phase) of the cell cycle is fundamental in our understanding of cell cycle kinetics, cell proliferation, and DNA replication timing programs. Most S-phase duration estimates that exist for plants are based on indirect measurements. We present a method for directly estimating S-phase duration by pulse-labeling root tips or actively dividing suspension cells with the halogenated thymidine analog 5-ethynl-2'-deoxyuridine (EdU) and analyzing the time course of replication with bivariate flow cytometry. The transition between G1 and G2 DNA contents can be followed by measuring the mean DNA content of EdU-labeled S-phase nuclei as a function of time after the labeling pulse. We applied this technique to intact root tips of maize (Zea mays L.), rice (Oryza sativa L.), barley (Hordeum vulgare L.), and wheat (Triticum aestivum L.), and to actively dividing cell cultures of Arabidopsis (Arabidopsis thaliana (L.) Heynh.) and rice. Estimates of S-phase duration in root tips were remarkably consistent, varying only by ~3-fold, although the genome sizes of the species analyzed varied >40-fold.
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Affiliation(s)
- Leigh Mickelson-Young
- Department of Plant and Microbial Biology, North Carolina State University, Raleigh, NC 27695, USA
| | - Emily Wear
- Department of Plant and Microbial Biology, North Carolina State University, Raleigh, NC 27695, USA
| | - Patrick Mulvaney
- Department of Plant and Microbial Biology, North Carolina State University, Raleigh, NC 27695, USA
| | - Tae-Jin Lee
- Department of Horticultural Science, North Carolina State University, Raleigh, NC 27695, USA
- Present address: Syngenta Crop Protection, LLC, Research Triangle Park, NC 27709, USA
| | - Eric S Szymanski
- Department of Plant and Microbial Biology, North Carolina State University, Raleigh, NC 27695, USA
- Present address: Department of Biochemistry, Duke University, Durham, NC 27710, USA
| | - George Allen
- Department of Horticultural Science, North Carolina State University, Raleigh, NC 27695, USA
| | - Linda Hanley-Bowdoin
- Department of Plant and Microbial Biology, North Carolina State University, Raleigh, NC 27695, USA
| | - William Thompson
- Department of Plant and Microbial Biology, North Carolina State University, Raleigh, NC 27695, USA
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14
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Tian S, Wu J, Li F, Zou J, Liu Y, Zhou B, Bai Y, Sun MX. NtKRP, a kinesin-12 protein, regulates embryo/seed size and seed germination via involving in cell cycle progression at the G2/M transition. Sci Rep 2016; 6:35641. [PMID: 27779252 PMCID: PMC5078848 DOI: 10.1038/srep35641] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2016] [Accepted: 10/03/2016] [Indexed: 01/01/2023] Open
Abstract
Kinesins comprise a superfamily of microtubule-based motor proteins involved in essential processes in plant development, but few kinesins have been functionally identified during seed development. Especially, few kinesins that regulate cell division during embryogenesis have been identified. Here we report the functional characterization of NtKRP, a motor protein of the kinesin-12 family. NtKRP is predominantly expressed in embryos and embryonic roots. NtKRP RNAi lines displayed reductions in cell numbers in the meristematic zone, in embryonic root length, and in mature embryo and seed sizes. Furthermore, we also show that CDKA;1 binds to NtKRP at the consensus phosphorylation sites and that the decreased cell numbers in NtKRP-silenced embryos are due to a delay in cell division cycle at the G2/M transition. In addition, binding between the cargo-binding tail domain of NtKRP and CDKA; 1 was also determined. Our results reveal a novel molecular pathway that regulates embryo/seed development and critical role of kinesin in temporal and spatial regulation of a specific issue of embryo developmental.
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Affiliation(s)
- Shujuan Tian
- College of Life Sciences, State Key Laboratory of Hybrid Rice, Wuhan University, Wuhan, 430072, China
| | - Jingjing Wu
- College of Life Sciences, State Key Laboratory of Hybrid Rice, Wuhan University, Wuhan, 430072, China
| | - Fen Li
- College of Life Sciences, State Key Laboratory of Hybrid Rice, Wuhan University, Wuhan, 430072, China
- College of Life Science, Henan Normal University, Xinxiang 453007, China
| | - Jianwei Zou
- College of Life Sciences, State Key Laboratory of Hybrid Rice, Wuhan University, Wuhan, 430072, China
| | - Yuwen Liu
- College of Life Sciences, State Key Laboratory of Hybrid Rice, Wuhan University, Wuhan, 430072, China
| | - Bing Zhou
- College of Life Sciences, State Key Laboratory of Hybrid Rice, Wuhan University, Wuhan, 430072, China
| | - Yang Bai
- College of Life Sciences, State Key Laboratory of Hybrid Rice, Wuhan University, Wuhan, 430072, China
| | - Meng-Xiang Sun
- College of Life Sciences, State Key Laboratory of Hybrid Rice, Wuhan University, Wuhan, 430072, China
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15
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Abstract
The Golgi complex of mammalian cells is composed of stacks of flattened cisternae that are connected by tubules to form a continuous membrane system, also known as the Golgi ribbon. At the onset of mitosis, the Golgi ribbon is progressively fragmented into small tubular-vesicular clusters and it is reconstituted before completion of cytokinesis. The investigation of the mechanisms behind this reversible cycle of disassembly and reassembly has led to the identification of structural Golgi proteins and regulators. Moreover, these studies allowed to discover that disassembly of the ribbon is necessary for cell entry into mitosis. Here, we describe an in vitro assay that reproduces the mitotic Golgi fragmentation and that has been successfully employed to identify many important mechanisms and proteins involved in the mitotic Golgi reorganization.
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Affiliation(s)
- Inmaculada Ayala
- Institute of Protein Biochemistry, National Research Council of Italy, Via P. Castellino 111, 80131, Naples, Italy.
| | - Antonino Colanzi
- Institute of Protein Biochemistry, National Research Council of Italy, Via P. Castellino 111, 80131, Naples, Italy
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16
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Thoompumkal IJ, Subba Rao MRK, Kumaraswamy A, Krishnan R, Mahalingam S. GNL3L Is a Nucleo-Cytoplasmic Shuttling Protein: Role in Cell Cycle Regulation. PLoS One 2015; 10:e0135845. [PMID: 26274615 PMCID: PMC4537249 DOI: 10.1371/journal.pone.0135845] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2015] [Accepted: 07/27/2015] [Indexed: 01/01/2023] Open
Abstract
GNL3L is an evolutionarily conserved high molecular weight GTP binding nucleolar protein belonging to HSR1-MMR1 subfamily of GTPases. The present investigation reveals that GNL3L is a nucleo-cytoplasmic shuttling protein and its export from the nucleus is sensitive to Leptomycin B. Deletion mutagenesis reveals that the C-terminal domain (amino acids 501–582) is necessary and sufficient for the export of GNL3L from the nucleus and the exchange of hydrophobic residues (M567, L570 and 572) within the C-terminal domain impairs this process. Results from the protein-protein interaction analysis indicate that GNL3L interaction with CRM1 is critical for its export from the nucleus. Ectopic expression of GNL3L leads to lesser accumulation of cells in the ‘G2/M’ phase of cell cycle whereas depletion of endogenous GNL3L results in ‘G2/M’ arrest. Interestingly, cell cycle analysis followed by BrdU labeling assay indicates that significantly increased DNA synthesis occurs in cells expressing nuclear export defective mutant (GNL3L∆NES) compared to the wild type or nuclear import defective GNL3L. Furthermore, increased hyperphosphorylation of Rb at Serine 780 and the upregulation of E2F1, cyclins A2 and E1 upon ectopic expression of GNL3L∆NES results in faster ‘S’ phase progression. Collectively, the present study provides evidence that GNL3L is exported from the nucleus in CRM1 dependent manner and the nuclear localization of GNL3L is important to promote ‘S’ phase progression during cell proliferation.
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Affiliation(s)
- Indu Jose Thoompumkal
- Laboratory of Molecular Virology and Cell Biology, Department of Biotechnology, Bhupat and Jyoti Mehta School of Biosciences, Indian Institute of Technology-Madras, Chennai, 600 036, India
| | - Malireddi Rama Krishna Subba Rao
- Laboratory of Molecular Virology and Cell Biology, Department of Biotechnology, Bhupat and Jyoti Mehta School of Biosciences, Indian Institute of Technology-Madras, Chennai, 600 036, India
| | - Anbarasu Kumaraswamy
- Laboratory of Molecular Virology and Cell Biology, Department of Biotechnology, Bhupat and Jyoti Mehta School of Biosciences, Indian Institute of Technology-Madras, Chennai, 600 036, India
- National Cancer Tissue Biobank, Department of Biotechnology, Bhupat and Jyoti Mehta School of Biosciences, Indian Institute of Technology-Madras, Chennai, 600 036, India
| | - Rehna Krishnan
- Laboratory of Molecular Virology and Cell Biology, Department of Biotechnology, Bhupat and Jyoti Mehta School of Biosciences, Indian Institute of Technology-Madras, Chennai, 600 036, India
| | - Sundarasamy Mahalingam
- Laboratory of Molecular Virology and Cell Biology, Department of Biotechnology, Bhupat and Jyoti Mehta School of Biosciences, Indian Institute of Technology-Madras, Chennai, 600 036, India
- National Cancer Tissue Biobank, Department of Biotechnology, Bhupat and Jyoti Mehta School of Biosciences, Indian Institute of Technology-Madras, Chennai, 600 036, India
- * E-mail:
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17
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Rashid NN, Yusof R, Watson RJ. A B-myb--DREAM complex is not critical to regulate the G2/M genes in HPV-transformed cell lines. Anticancer Res 2014; 34:6557-6563. [PMID: 25368258] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
BACKGROUND/AIM It is well-established that HPV E7 proteins, encoded by human papillomavirus (HPV) genes, frequently associated with cervical cancers bind avidly to the retinoblastoma (RB) family of pocket proteins and disrupt their association with members of the E2F transcription factor family. Our previous study showed that the repressive p130-dimerization partner, RB-like, E2F and multi-vulval class (DREAM) complex was disrupted by HPV16 E7 proteins in order to maintain the viral replication in CaSki cells. However, we would like to address whether the activator B-myb-DREAM complex is critical in regulating the replication and mitosis phase since our previous study showed increased B-myb-DREAM expression in HPV-transformed cell lines when compared to control cells. RESULTS The association of B-myb with both LIN-54 and LIN-9 was equally decreased by depleting LIN-54 in CaSki cells. Flow cytometry analysis showed that LIN-54 depletion caused an increased proportion of G2/M cells in T98G, SiHa and CaSki cells. The mRNA levels of certain S/G2 genes such as cyclin B, aurora kinase A and Polo-like kinase 1 have demonstrated a marginal increased in CaSki-Lin-54-depleted cells when compared to SiHa- and T98G-Lin-54-depleted cells. We further confirmed this experiment by depleting the B-myb itself in CaSki cells and the results showed the same pattern of cell cycle and mRNA levels for S/G2 genes when compared to LIN-54- and LIN-9-depleted cells. CONCLUSION The B-myb-DREAM complex might not be vital for progression through mitosis in cells lacking a G1/S checkpoint and not as crucial as the p130-DREAM complex for the survival of the HPV virus.
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Affiliation(s)
- Nurshamimi Nor Rashid
- Section of Virology, Department of Medicine, Imperial College London, London, U.K. Department of Molecular Medicine, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia
| | - Rohana Yusof
- Department of Molecular Medicine, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia
| | - Roger J Watson
- Section of Virology, Department of Medicine, Imperial College London, London, U.K. Institute of Biomedical Research, College of Medical and Dental Sciences, University of Birmingham, Birmingham, U.K
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18
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Abstract
Chemical inhibitors of the G2 checkpoint can sensitize p53-defective cancer cells to DNA damage and several are in preclinical or clinical development. These compounds are commonly thought to increase killing at the G2/M transition by forcing cells to divide with unrepaired DNA. We examined the effects of the ATM/ATR inhibitor caffeine and the Chk1 inhibitor isogranulatimide on the clonogenic survival of two p53-defective cell lines, MCF7-mp53 and HCT-116 p53-/- cells, when added at different times after exposure to ionizing radiation. Exposure 16-24 h after irradiation, when G2 arrest is maximal, forced premature entry into mitosis but increased clonogenic survival. Radiosensitization occurred mostly upon exposure between 2 and 16 h after irradiation, correlating with S-phase traversal. These results suggest that inhibition of the S phase activities of ATM/ATR and Chk1 may be more relevant to radiosensitization of p53-defective cells than G2 checkpoint abrogation and that careful scheduling of combination treatments might be required for synergistic antitumour effects in vivo.
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Affiliation(s)
- Christopher M Sturgeon
- Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, British Columbia, Canada
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19
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Su C, Deaton RA, Iglewsky MA, Valencia TG, Grant SR. PKN Activation via Transforming Growth Factor-β1 (TGF-β1) Receptor Signaling Delays G2/M Phase Transition in Vascular Smooth Muscle Cells. Cell Cycle 2014; 6:739-49. [PMID: 17374997 DOI: 10.4161/cc.6.6.3985] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
The transition of vascular smooth muscle cells (VSMCs) from G2 phase into the M (mitosis) phase of the cell cycle is a tightly controlled process. As an arterial SMC prepares for a G2/M transition, the cell has primed the Cdc2/cyclinB1 complex for activation by the phosphorylation of threonine-161 residue on Cdc2. This phosphorylation is necessary but not sufficient for the VSMC to enter into the M phase. In order to enter into mitosis, a phosphatase, Cdc25C, must first dephosphorylate two other critical residues: tyrosine-15 and threonine-14. If Cdc25C phosphatase activity is blocked, VSMC entry into mitosis is delayed. However, how the activity of Cdc25C is regulated has not been fully illustrated. In an earlier published study we have demonstrated that exposure of the VSMC line, PAC-1, to Transforming growth factor-beta1 (TGF-beta1), activated PKN (a RhoA-dependent kinase). Here we show that exposure to TGF-beta1 delays the G2/M transition by 2 hrs in G1/S synchronized and released PAC-1 culture. This delay is abolished by the RhoA kinase inhibitors, HA1077 or Y-27632. More importantly, RNAi knockdown of PKN expression prevents the G2/M transition delay induced by TGF-beta1. Changes in PKN activity temporally correlates to the G2/M transition timing. Moreover, Cdc25C is phosphorylated by the TGF-beta1-activated PKN. PKN and Cdc25C coimmunoprecipitate with each other. Finally, PKN and Cdc25C colocalize to the nuclear region only during the critical period of time prior to entry into the M phase. Our data demonstrate that Cdc25C activity is negatively regulated by TGF-beta1-stimulated PKN. Once activated through TGF-beta1 signaling, PKN binds to and phosphorylates Cdc25C. The physical interaction and phosphorylation result in an inactivation of Cdc25C and delay the VSMC entry into the M stage of the cell cycle.
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Affiliation(s)
- Chang Su
- Department of Integrative Physiology, Cardiovascular Research Institute, University of North Texas Health Science Center, Fort Worth, Texas 76107, USA
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20
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Nakai N, Fujita R, Kawano F, Takahashi K, Ohira T, Shibaguchi T, Nakata K, Ohira Y. Retardation of C2C12 myoblast cell proliferation by exposure to low-temperature atmospheric plasma. J Physiol Sci 2014; 64:365-75. [PMID: 25034108 PMCID: PMC10717780 DOI: 10.1007/s12576-014-0328-5] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2014] [Accepted: 06/27/2014] [Indexed: 10/25/2022]
Abstract
As the first step in evaluating the possibility of low-temperature atmospheric plasma for clinical applications in the treatment of rhabdomyosarcoma (RMS), we determined the effects of plasma exposure on C2C12 myoblasts. The low-temperature atmospheric plasma was generated through an electrical discharge in argon gas. One minute of plasma exposure every 24 h inhibited the cell proliferation, whereas myoblast differentiation was not affected. Plasma exposure increased the phosphorylation of ERK and JNK at 30 min after the exposure, but the phosphorylation of both was decreased to less than control levels at 1 and 4 h after the exposure. Plasma exposure increased the percentage of cells in the G2/M phase at 8 h after the exposure. In conclusion, plasma exposure retarded the proliferation of C2C12 myoblasts by G2/M arrest. Therefore, plasma exposure can be a possible treatment for the anti-proliferative effects of malignant tumors, such as RMS, without affecting differentiated skeletal muscle cells.
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Affiliation(s)
- Naoya Nakai
- Department of Health and Sports Sciences, Graduate School of Medicine, Osaka University, 1-17 Machikaneyama-cho, Toyonaka, Osaka, 560-0043, Japan,
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21
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Jung HW, Park I, Ghil S. Cannabinoid receptor activation inhibits cell cycle progression by modulating 14-3-3β. Cell Mol Biol Lett 2014; 19:347-60. [PMID: 25002257 PMCID: PMC6275927 DOI: 10.2478/s11658-014-0200-x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2013] [Accepted: 07/01/2014] [Indexed: 11/20/2022] Open
Abstract
Cannabinoids display various pharmacological activities, including tumor regression, anti-inflammatory and neuroprotective effects. To investigate the molecular mechanisms underlying the pharmacological effects of cannabinoids, we used a yeast two-hybrid system to screen a mouse brain cDNA library for proteins interacting with type 1 cannabinoid receptor (CB1R). Using the intracellular loop 3 of CB1R as bait, we identified 14-3-3β as an interacting partner of CB1R and confirmed their interaction using affinity-binding assays. 14-3-3β has been reported to induce a cell cycle delay at the G2/M phase. We tested the effects of cannabinoids on cell cycle progression in HeLa cells synchronized using a double-thymidine block-and-release protocol and found an increase in the population of G2/M phase cells. We further found that CB1R activation augmented the interaction of 14-3-3β with Wee1 and Cdc25B, and promoted phosphorylation of Cdc2 at Tyr-15. These results suggest that cannabinoids induce cell cycle delay at the G2/M phase by activating 14-3-3β.
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Affiliation(s)
- Hye-Won Jung
- Department of Life Science, Kyonggi University, Suwon, 443-760 Republic of Korea
| | - Inae Park
- Department of Life Science, Kyonggi University, Suwon, 443-760 Republic of Korea
| | - Sungho Ghil
- Department of Life Science, Kyonggi University, Suwon, 443-760 Republic of Korea
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22
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Zhang H, Xiong ZM, Cao K. Mechanisms controlling the smooth muscle cell death in progeria via down-regulation of poly(ADP-ribose) polymerase 1. Proc Natl Acad Sci U S A 2014; 111:E2261-70. [PMID: 24843141 PMCID: PMC4050581 DOI: 10.1073/pnas.1320843111] [Citation(s) in RCA: 69] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Hutchinson-Gilford progeria syndrome (HGPS) is a severe human premature aging disorder caused by a lamin A mutant named progerin. Death occurs at a mean age of 13 y from cardiovascular problems. Previous studies revealed loss of vascular smooth muscle cells (SMCs) in the media of large arteries in a patient with HGPS and two mouse models, suggesting a causal connection between the SMC loss and cardiovascular malfunction. However, the mechanisms of how progerin leads to massive SMC loss are unknown. In this study, using SMCs differentiated from HGPS induced pluripotent stem cells, we show that HGPS SMCs exhibit a profound proliferative defect, which is primarily caused by caspase-independent cell death. Importantly, progerin accumulation stimulates a powerful suppression of PARP1 and consequently triggers an activation of the error-prone nonhomologous end joining response. As a result, most HGPS SMCs exhibit prolonged mitosis and die of mitotic catastrophe. This study demonstrates a critical role of PARP1 in mediating SMC loss in patients with HGPS and elucidates a molecular pathway underlying the progressive SMC loss in progeria.
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Affiliation(s)
- Haoyue Zhang
- Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, MD 20742
| | - Zheng-Mei Xiong
- Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, MD 20742
| | - Kan Cao
- Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, MD 20742
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23
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Niu Y, Wang Z, Huang H, Zhong S, Cai W, Xie Y, Shi G. Activated pregnane X receptor inhibits cervical cancer cell proliferation and tumorigenicity by inducing G2/M cell-cycle arrest. Cancer Lett 2014; 347:88-97. [PMID: 24486740 DOI: 10.1016/j.canlet.2014.01.026] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2013] [Revised: 01/02/2014] [Accepted: 01/24/2014] [Indexed: 02/05/2023]
Abstract
Pregnane X receptor (PXR) regulates cell proliferation and carcinogenesis in female reproductive tissue. We showed that PXR was expressed in cervical cells and tissue samples. PXR were lower or greatly diminished in cancer tissues compared to normal control. Functionally, activation of human PXR by rifampicin or ectopic expression of constitutively-activated human VP-PXR inhibited cervical cell proliferation. Constitutively-activated VP-PXR attenuated CaSki and HeLa xenograft tumor growth in nude mice compared with control. The cellular proliferation inhibition of PXR by causing G2/M cell-cycle arrest is involved up-regulation of Cullin1-3, MAD2L1, and down-regulation of ANAPC2 and CDKN1A. Our data suggests that PXR signaling inhibits tumor cell proliferation in vitro and cervical carcinoma growth in vivo.
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Affiliation(s)
- Yongdong Niu
- Department of Pharmacology, Shantou University Medical College, Guangdong, China
| | - Ziliang Wang
- Cancer Research Laboratory, Fudan University Shanghai Cancer Center, Department of Oncology, Fudan University, Shanghai, China
| | - Haihua Huang
- Department of Pathology, Second Affiliated Hospital of Shantou University Medical College, Guangdong, China
| | - Shuping Zhong
- Department of Biochemistry and Molecular Biology, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA
| | - Wenfeng Cai
- Department of Pharmacology, Shantou University Medical College, Guangdong, China
| | - Yangmin Xie
- Department of Experimental Animal Center, Medical College of Shantou University, Guangdong, China
| | - Ganggang Shi
- Department of Pharmacology, Shantou University Medical College, Guangdong, China.
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24
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Abstract
β-catenin plays a pivotal role in organogenesis and oncogenesis. Alterations in β-catenin expression are common in pancreatic cancer, which is an extremely aggressive malignancy with a notably poor prognosis. In this report, we analyzed the apoptotic activity of withanolide-D (witha-D), a steroidal lactone that was purified from an Indian medicinal plant, Withania somnifera, and its underlying mechanism of action. Witha-D induced apoptosis in pancreatic ductal adenocarcinoma cells by prompting cell-cycle arrest at the G2/M phase. This lactone abrogated β-catenin signaling in these cells regardless of disease grade, mutational status, and gemcitabine sensitivity. Witha-D also upregulated E-cadherin in most cells, thereby supporting the inversion of the epithelial-mesenchymal transition. Furthermore, the Akt/Gsk3β kinase cascade was identified as a critical mediator of G2/M regulation and β-catenin signaling. Witha-D deactivated Akt, which failed to promote Gsk3β deactivation phosphorylation. Consequently, activated Gsk3β facilitated β-catenin destruction in pancreatic carcinoma cells. The knockdown of Chk1 and Chk2 further activated Akt and reversed the molecular signal. Taken together, the results of the current study represent the first evidence of β-catenin signal crosstalk during the G2/M phase by functionally inactivating Akt via witha-D treatment in pancreatic cancer cells. In conclusion, this finding suggests the potential identification of a new lead molecule in the treatment of pancreatic adenocarcinoma.
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Affiliation(s)
- Sayantani Sarkar
- Cancer Biology and Inflammatory Disorder Division, Council of Scientific and Industrial Research-Indian Institute of Chemical Biology, 4, Raja S.C. Mallick Road, Kolkata 700032, West Bengal, India Bio-Processing Unit, Department of Bio-Technology, Govt. of India, Mohali, Punjab, India
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Matsumoto Y. [Smart choice between two DNA double-strand break repair mechanisms]. Igaku Butsuri 2014; 34:57-64. [PMID: 25693292] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
DNA double-strand break (DSB) is considered most deleterious among radiation-induced DNA damages and most relevant to the biological effects of radiation. In eukaryotic cells, DSB is repaired mainly through two pathways: non-homologous end-joining (NHEJ) and homologous recombination (HR). These repair pathways seem to play complementary roles. NHEJ is considered less accurate than HR, but HR is available only in late S and G2 phases in vertebrates. Recent studies elucidated how cells choose one from these two pathways depending on the circumstance: cell cycle phase, complexity of DNA damage and chromatin structure.
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Araki S, Kato K, Suzuki T, Okumura T, Machida Y, Ito M. Cosuppression of NtmybA1 and NtmybA2 causes downregulation of G2/M phaseexpressed genes and negatively affects both cell division and expansion in tobacco. Plant Signal Behav 2013; 8:doi: 10.4161/psb.26780. [PMID: 24494234 PMCID: PMC4091115 DOI: 10.4161/psb.26780] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/18/2013] [Revised: 10/10/2013] [Accepted: 10/10/2013] [Indexed: 06/03/2023]
Abstract
During the plant cell cycle, genes preferentially expressed at the G2/M phase are regulated by R1R2R3-type Myb transcription factors. To address the function of 2 tobacco R1R2R3-Myb proteins, NtmybA1 and NtmybA2, we generated transgenic tobacco plants in which endogenous NtmybA2 transcripts were significantly decreased, presumably due to cosuppression triggered by the presence of the NtmybA2 transgene. These lines showed a concomitant downregulation of structurally related NtmybA1 and many G2/M-expressed genes. In the cosuppression plants, we found a dwarf phenotype due to both reduced cell size and decreased cell number. Our results provide evidence confirming our previous view that NtmybA1 and NtmybA2 may regulate cell expansion as well as cell division by transcriptionally activating many G2/M-expressed genes in tobacco.
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Affiliation(s)
- Satoshi Araki
- Division of Biological Science; Graduate School of Science; Nagoya University; Chikusa-ku, Nagoya, Japan
| | - Kiichi Kato
- Graduate School of Bioagricultural Sciences; Nagoya University; Chikusa, Nagoya, Japan
| | - Toshiya Suzuki
- Graduate School of Bioagricultural Sciences; Nagoya University; Chikusa, Nagoya, Japan
- JST; CREST; Chikusa, Nagoya, Japan
| | - Toru Okumura
- Graduate School of Bioagricultural Sciences; Nagoya University; Chikusa, Nagoya, Japan
| | - Yasunori Machida
- Division of Biological Science; Graduate School of Science; Nagoya University; Chikusa-ku, Nagoya, Japan
| | - Masaki Ito
- Graduate School of Bioagricultural Sciences; Nagoya University; Chikusa, Nagoya, Japan
- JST; CREST; Chikusa, Nagoya, Japan
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Araki S, Kato K, Suzuki T, Okumura T, Machida Y, Ito M. Cosuppression of NtmybA1 and NtmybA2 causes downregulation of G2/M phaseexpressed genes and negatively affects both cell division and expansion in tobacco. Plant Signal Behav 2013; 8:doi: 10.4161/psb.26780. [PMID: 24494234 PMCID: PMC4091115] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Received: 09/18/2013] [Revised: 10/10/2013] [Accepted: 10/10/2013] [Indexed: 12/16/2023]
Abstract
During the plant cell cycle, genes preferentially expressed at the G2/M phase are regulated by R1R2R3-type Myb transcription factors. To address the function of 2 tobacco R1R2R3-Myb proteins, NtmybA1 and NtmybA2, we generated transgenic tobacco plants in which endogenous NtmybA2 transcripts were significantly decreased, presumably due to cosuppression triggered by the presence of the NtmybA2 transgene. These lines showed a concomitant downregulation of structurally related NtmybA1 and many G2/M-expressed genes. In the cosuppression plants, we found a dwarf phenotype due to both reduced cell size and decreased cell number. Our results provide evidence confirming our previous view that NtmybA1 and NtmybA2 may regulate cell expansion as well as cell division by transcriptionally activating many G2/M-expressed genes in tobacco.
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Affiliation(s)
- Satoshi Araki
- Division of Biological Science; Graduate School of Science; Nagoya University; Chikusa-ku, Nagoya, Japan
| | - Kiichi Kato
- Graduate School of Bioagricultural Sciences; Nagoya University; Chikusa, Nagoya, Japan
| | - Toshiya Suzuki
- Graduate School of Bioagricultural Sciences; Nagoya University; Chikusa, Nagoya, Japan
- JST; CREST; Chikusa, Nagoya, Japan
| | - Toru Okumura
- Graduate School of Bioagricultural Sciences; Nagoya University; Chikusa, Nagoya, Japan
| | - Yasunori Machida
- Division of Biological Science; Graduate School of Science; Nagoya University; Chikusa-ku, Nagoya, Japan
| | - Masaki Ito
- Graduate School of Bioagricultural Sciences; Nagoya University; Chikusa, Nagoya, Japan
- JST; CREST; Chikusa, Nagoya, Japan
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Salotti J, Dias MH, Koga MM, Armelin HA. Fibroblast growth factor 2 causes G2/M cell cycle arrest in ras-driven tumor cells through a Src-dependent pathway. PLoS One 2013; 8:e72582. [PMID: 23991123 PMCID: PMC3753234 DOI: 10.1371/journal.pone.0072582] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2011] [Accepted: 07/17/2013] [Indexed: 11/26/2022] Open
Abstract
We recently reported that paracrine Fibroblast Growth Factor 2 (FGF2) triggers senescence in Ras-driven Y1 and 3T3Ras mouse malignant cell lines. Here, we show that although FGF2 activates mitogenic pathways in these Ras-dependent malignant cells, it can block cell proliferation and cause a G2/M arrest. These cytostatic effects of FGF2 are inhibited by PD173074, an FGF receptor (FGFR) inhibitor. To determine which downstream pathways are induced by FGF2, we tested specific inhibitors targeting mitogen-activated protein kinase (MEK), phosphatidylinositol 3 kinase (PI3K) and protein kinase C (PKC). We show that these classical mitogenic pathways do not mediate the cytostatic activity of FGF2. On the other hand, the inhibition of Src family kinases rescued Ras-dependent malignant cells from the G2/M irreversible arrest induced by FGF2. Taken together, these data indicate a growth factor-sensitive point in G2/M that likely involves FGFR/Ras/Src pathway activation in a MEK, PI3K and PKC independent manner.
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Affiliation(s)
- Jacqueline Salotti
- Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, São Paulo, Brazil
| | - Matheus H. Dias
- Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, São Paulo, Brazil
- Instituto Butantan, CATcepid, São Paulo, Brazil
| | - Marianna M. Koga
- Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, São Paulo, Brazil
| | - Hugo A. Armelin
- Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, São Paulo, Brazil
- Instituto Butantan, CATcepid, São Paulo, Brazil
- * E-mail:
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Yong KJ, Milenic DE, Baidoo KE, Brechbiel MW. Sensitization of tumor to ²¹²Pb radioimmunotherapy by gemcitabine involves initial abrogation of G2 arrest and blocked DNA damage repair by interference with Rad51. Int J Radiat Oncol Biol Phys 2013; 85:1119-26. [PMID: 23200172 PMCID: PMC3594422 DOI: 10.1016/j.ijrobp.2012.09.015] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2012] [Revised: 09/05/2012] [Accepted: 09/14/2012] [Indexed: 12/22/2022]
Abstract
PURPOSE To elucidate the mechanism of the therapeutic efficacy of targeted α-particle radiation therapy using (212)Pb-TCMC-trastuzumab together with gemcitabine for treatment of disseminated peritoneal cancers. METHODS AND MATERIALS Mice bearing human colon cancer LS-174T intraperitoneal xenografts were pretreated with gemcitabine, followed by (212)Pb-TCMC-trastuzumab and compared with controls. RESULTS Treatment with (212)Pb-TCMC-trastuzumab increased the apoptotic rate in the S-phase-arrested tumors induced by gemcitabine at earlier time points (6 to 24 hours). (212)Pb-TCMC-trastuzumab after gemcitabine pretreatment abrogated G2/M arrest at the same time points, which may be associated with the inhibition of Chk1 phosphorylation and, in turn, cell cycle perturbation, resulting in apoptosis. (212)Pb-TCMC-trastuzumab treatment after gemcitabine pretreatment caused depression of DNA synthesis, DNA double-strand breaks, accumulation of unrepaired DNA, and down-regulation of Rad51 protein, indicating that DNA damage repair was blocked. In addition, modification in the chromatin structure of p21 may be associated with transcriptionally repressed chromatin states, indicating that the open structure was delayed at earlier time points. CONCLUSION These findings suggest that the cell-killing efficacy of (212)Pb-TCMC-trastuzumab after gemcitabine pretreatment may be associated with abrogation of the G2/M checkpoint, inhibition of DNA damage repair, and chromatin remodeling.
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Affiliation(s)
- Kwon Joong Yong
- Radioimmune & Inorganic Chemistry Section, Radiation Oncology Branch, National Cancer Institute, National Institutes of Health, Bethesda MD
| | - Diane E. Milenic
- Radioimmune & Inorganic Chemistry Section, Radiation Oncology Branch, National Cancer Institute, National Institutes of Health, Bethesda MD
| | - Kwamena E. Baidoo
- Radioimmune & Inorganic Chemistry Section, Radiation Oncology Branch, National Cancer Institute, National Institutes of Health, Bethesda MD
| | - Martin W. Brechbiel
- Radioimmune & Inorganic Chemistry Section, Radiation Oncology Branch, National Cancer Institute, National Institutes of Health, Bethesda MD
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Qian W, Choi S, Gibson GA, Watkins SC, Bakkenist CJ, Van Houten B. Mitochondrial hyperfusion induced by loss of the fission protein Drp1 causes ATM-dependent G2/M arrest and aneuploidy through DNA replication stress. J Cell Sci 2012; 125:5745-57. [PMID: 23015593 PMCID: PMC4074216 DOI: 10.1242/jcs.109769] [Citation(s) in RCA: 156] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Mitochondrial fission and fusion cycles are integrated with cell cycle progression. In this paper, we demonstrate that the inhibition of mitochondrial fission protein Drp1 causes an unexpected delay in G2/M cell cycle progression and aneuploidy. In investigating the underlying molecular mechanism, we revealed that inhibiting Drp1 triggers replication stress, which is mediated by a hyperfused mitochondrial structure and unscheduled expression of cyclin E in the G2 phase. This persistent replication stress then induces an ATM-dependent activation of the G2 to M transition cell cycle checkpoint. Knockdown of ATR, an essential kinase in preventing replication stress, significantly enhanced DNA damage and cell death of Drp1-deficienct cells. Persistent mitochondrial hyperfusion also induces centrosomal overamplification and chromosomal instability, which are causes of aneuploidy. Analysis using cells depleted of mitochondrial DNA revealed that these events are not mediated by the defects in mitochondrial ATP production and reactive oxygen species (ROS) generation. Thus dysfunctional mitochondrial fission directly induces genome instability by replication stress, which then initiates the DNA damage response. Our findings provide a novel mechanism that contributes to the cellular dysfunction and diseases associated with altered mitochondrial dynamics.
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Affiliation(s)
- Wei Qian
- Department of Pharmacology and Chemical Biology, Hillman Cancer CenterPittsburgh, PA 15213USA
- The University of Pittsburgh Cancer Institute, Hillman Cancer CenterPittsburgh, PA 15213USA
| | - Serah Choi
- Medical Scientist Training Program, Molecular Pharmacology Graduate Program, Hillman Cancer CenterPittsburgh, PA 15213USA
- The University of Pittsburgh Cancer Institute, Hillman Cancer CenterPittsburgh, PA 15213USA
| | - Gregory A. Gibson
- Department of Cell Biology and Physiology, Center for Biological Imaging, University of Pittsburgh, Pittsburgh, PA 15261, USA
| | - Simon C. Watkins
- Department of Cell Biology and Physiology, Center for Biological Imaging, University of Pittsburgh, Pittsburgh, PA 15261, USA
| | - Christopher J. Bakkenist
- Department of Pharmacology and Chemical Biology, Hillman Cancer CenterPittsburgh, PA 15213USA
- Department of Radiation Oncology, University of Pittsburgh School of Medicine and, Hillman Cancer CenterPittsburgh, PA 15213USA
- The University of Pittsburgh Cancer Institute, Hillman Cancer CenterPittsburgh, PA 15213USA
| | - Bennett Van Houten
- Department of Pharmacology and Chemical Biology, Hillman Cancer CenterPittsburgh, PA 15213USA
- The University of Pittsburgh Cancer Institute, Hillman Cancer CenterPittsburgh, PA 15213USA
- Author for correspondence ()
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Deng W, Pang PS, Tsang CM, Hau PM, Yip YL, Cheung ALM, Tsao SW. Epstein-Barr virus-encoded latent membrane protein 1 impairs G2 checkpoint in human nasopharyngeal epithelial cells through defective Chk1 activation. PLoS One 2012; 7:e39095. [PMID: 22761726 PMCID: PMC3382577 DOI: 10.1371/journal.pone.0039095] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2012] [Accepted: 05/18/2012] [Indexed: 11/19/2022] Open
Abstract
Nasopharyngeal carcinoma (NPC) is a common cancer in Southeast Asia, particularly in southern regions of China. EBV infection is closely associated with NPC and has long been postulated to play an etiological role in the development of NPC. However, the role of EBV in malignant transformation of nasopharyngeal epithelial cells remains enigmatic. The current hypothesis of NPC development is that premalignant nasopharyngeal epithelial cells harboring genetic alterations support EBV infection and expression of EBV genes induces further genomic instability to facilitate the development of NPC. The latent membrane protein 1 (LMP1) is a well-documented EBV-encoded oncogene. The involvement of LMP1 in human epithelial malignancies has been implicated, but the mechanisms of oncogenic actions of LMP1, particularly in nasopharyngeal cells, are unclear. Here we observed that LMP1 expression in nasopharyngeal epithelial cells impaired G2 checkpoint, leading to formation of unrepaired chromatid breaks in metaphases after γ-ray irradiation. We further found that defective Chk1 activation was involved in the induction of G2 checkpoint defect in LMP1-expressing nasopharyngeal epithelial cells. Impairment of G2 checkpoint could result in loss of the acentrically broken chromatids and propagation of broken centric chromatids in daughter cells exiting mitosis, which facilitates chromosome instability. Our findings suggest that LMP1 expression facilitates genomic instability in cells under genotoxic stress. Elucidation of the mechanisms involved in LMP1-induced genomic instability in nasopharyngeal epithelial cells will shed lights on the understanding of role of EBV infection in NPC development.
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Affiliation(s)
- Wen Deng
- Department of Anatomy, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, China
| | - Pei Shin Pang
- Department of Anatomy, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, China
| | - Chi Man Tsang
- Department of Anatomy, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, China
| | - Pok Man Hau
- Department of Anatomy, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, China
| | - Yim Ling Yip
- Department of Anatomy, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, China
| | - Annie L. M. Cheung
- Department of Anatomy, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, China
| | - Sai Wah Tsao
- Department of Anatomy, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, China
- * E-mail:
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Kwintkiewicz J, Padilla-Banks E, Jefferson WN, Jacobs IM, Wade PA, Williams CJ. Metastasis-associated protein 3 (MTA3) regulates G2/M progression in proliferating mouse granulosa cells. Biol Reprod 2012; 86:1-8. [PMID: 22075476 PMCID: PMC3316264 DOI: 10.1095/biolreprod.111.096032] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2011] [Revised: 09/18/2011] [Accepted: 10/25/2011] [Indexed: 01/10/2023] Open
Abstract
Metastasis-associated protein 3 (MTA3) is a constituent of the Mi-2/nucleosome remodeling and deacetylase (NuRD) protein complex that regulates gene expression by altering chromatin structure and can facilitate cohesin loading onto DNA. The biological function of MTA3 within the NuRD complex is unknown. Herein, we show that MTA3 was expressed highly in granulosa cell nuclei of all ovarian follicle stages and at lower levels in corpora lutea. We tested the hypothesis that MTA3-NuRD complex function is required for granulosa cell proliferation. In the ovary, MTA3 interacted with NuRD proteins CHD4 and HDAC1 and the core cohesin complex protein RAD21. In cultured mouse primary granulosa cells, depletion of endogenous MTA3 using RNA interference slowed cell proliferation; this effect was rescued by coexpression of exogenous MTA3. Slowing of cell proliferation correlated with a significant decrease in cyclin B1 and cyclin B2 expression. Granulosa cell populations lacking MTA3 contained a significantly higher percentage of cells in G2/M phase and a lower percentage in S phase compared with control cells. Furthermore, MTA3 depletion slowed entry into M phase as indicated by reduced phosphorylation of histone H3 at serine 10. These findings provide the first evidence to date that MTA3 interacts with NuRD and cohesin complex proteins in the ovary in vivo and regulates G2/M progression in proliferating granulosa cells.
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Affiliation(s)
- Jakub Kwintkiewicz
- Reproductive Medicine Group, Laboratory of Reproductive and Developmental Toxicology, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, North Carolina
| | - Elizabeth Padilla-Banks
- Reproductive Medicine Group, Laboratory of Reproductive and Developmental Toxicology, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, North Carolina
| | - Wendy N. Jefferson
- Reproductive Medicine Group, Laboratory of Reproductive and Developmental Toxicology, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, North Carolina
| | - Ilana M. Jacobs
- Reproductive Medicine Group, Laboratory of Reproductive and Developmental Toxicology, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, North Carolina
| | - Paul A. Wade
- Eukaryotic Transcriptional Regulation Group, Laboratory of Molecular Carcinogenesis, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, North Carolina
| | - Carmen J. Williams
- Eukaryotic Transcriptional Regulation Group, Laboratory of Molecular Carcinogenesis, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, North Carolina
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Abstract
During the meiotic cycles in starfish oocytes, MAP kinase (MAPK) is involved in the meta-I arrest, the meiosis I to II transition, and the arrest at pronucleus stage (G1 and/or G2 phase). The eventual fate, either development or death, of mature eggs is also under the control of MAPK. Starfish oocytes are thus a useful model system to study multiple functions of skillful MAPK.
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Affiliation(s)
- Takeo Kishimoto
- Laboratory of Cell and Developmental Biology, Graduate School of Bioscience, Tokyo Institute of Technology, Nagatsuta 4259, Midoriku, Yokohama 226-8501, Japan.
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Abstract
All previous studies on the yeast metabolome have yielded a plethora of information on the components, function and organisation of low molecular mass and macromolecular components involved in the cellular metabolic network. Here we emphasise that an understanding of the global dynamics of the metabolome in vivo requires elucidation of the temporal dynamics of metabolic processes on many time-scales. We illustrate this using the 40 min oscillation in respiratory activity displayed in auto-synchronous continuously grown cultures of Saccharomyces cerevisiae, where respiration cycles between a phase of increased respiration (oxidative phase) and decreased respiration (reductive phase). Thereby an ultradian clock, i.e. a timekeeping device that runs through many cycles during one day, is involved in the co-ordination of the vast majority of events and processes in yeast. Through continuous online measurements, we first show that mitochondrial and redox physiology are intertwined to produce the temporal landscape on which cellular events occur. Next we look at the higher order processes of DNA duplication and mitochondrial structure to reveal that both events are choreographed during the respiratory cycles. Furthermore, spectral analysis using the discrete Fourier transformation of high-resolution (10 Hz) time-series of NAD(P)H confirms the existence of higher frequency components of biological origin and that these follow a scale-free architecture even in stable oscillating modes. A different signal-processing approach using discrete wavelet transformations (DWT) indicates that there is a significant contribution to the overall signal from ` ~5, ~ 10 and ~ 20-minutes cycles and the amplitudes of these cycles are phase-dependent. Further investigation (derivative of Gaussian continuous wavelet transformation) reveals that the observed 20-minutes cycles are actually confined to the reductive phase and consist of two ~15-minutes cycles. Moreover, the 5 and 10-minutes cycles are restricted to the oxidative phase of the cycle. The mitochondrial origin of these signals was confirmed by pulse-injection of the cytochrome c oxidase inhibitor H(2)S. We next discuss how these multi-oscillatory states can impinge on the apparently complex reactome (represented as a phase diagram of 1,650 chemical species that show oscillatory behaviour). We conclude that biological processes can be considerably more comprehensible when dynamic in vivo time-structure is taken into account.
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Affiliation(s)
- Kalesh Sasidharan
- Institute for Advanced Biosciences, Keio University, Nipponkoku 403-1, Daihouji, Tsuruoka City, Yamagata 997-0017, Japan.
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Leung L, Klopper AV, Grill SW, Harris WA, Norden C. Apical migration of nuclei during G2 is a prerequisite for all nuclear motion in zebrafish neuroepithelia. Development 2011; 138:5003-13. [PMID: 22028032 PMCID: PMC3201665 DOI: 10.1242/dev.071522] [Citation(s) in RCA: 101] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/15/2011] [Indexed: 11/20/2022]
Abstract
Nuclei in the proliferative pseudostratified epithelia of vastly different organisms exhibit a characteristic dynamics - the so-called interkinetic nuclear migration (IKNM). Although these movements are thought to be intimately tied to the cell cycle, little is known about the relationship between IKNM and distinct phases of the cell cycle and the role that this association plays in ensuring balanced proliferation and subsequent differentiation. Here, we perform a quantitative analysis of modes of nuclear migration during the cell cycle using a marker that enables the first unequivocal differentiation of all four phases in proliferating neuroepithelial cells in vivo. In zebrafish neuroepithelia, nuclei spend the majority of the cell cycle in S phase, less time in G1, with G2 and M being noticeably shorter still in comparison. Correlating cell cycle phases with nuclear movements shows that IKNM comprises rapid apical nuclear migration during G2 phase and stochastic nuclear motion during G1 and S phases. The rapid apical migration coincides with the onset of G2, during which we find basal actomyosin accumulation. Inhibiting the transition from G2 to M phase induces a complete stalling of nuclei, indicating that IKNM and cell cycle continuation cannot be uncoupled and that progression from G2 to M is a prerequisite for rapid apical migration. Taken together, these results suggest that IKNM involves an actomyosin-driven contraction of cytoplasm basal to the nucleus during G2, and that the stochastic nuclear movements observed in other phases arise passively due to apical migration in neighboring cells.
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Affiliation(s)
- Louis Leung
- Max Planck Institute of Molecular Cell Biology and Genetics, Pfotenhauerstraße 108, 01307 Dresden, Germany
| | - Abigail V. Klopper
- Max Planck Institute of Molecular Cell Biology and Genetics, Pfotenhauerstraße 108, 01307 Dresden, Germany
- Max Planck Institute for the Physics of Complex Systems, Nöthnitzer Straße 38, 01187 Dresden, Germany
| | - Stephan W. Grill
- Max Planck Institute of Molecular Cell Biology and Genetics, Pfotenhauerstraße 108, 01307 Dresden, Germany
- Max Planck Institute for the Physics of Complex Systems, Nöthnitzer Straße 38, 01187 Dresden, Germany
| | - William A. Harris
- Department of Physiology, Development and Neuroscience, University of Cambridge, Downing Street, Cambridge, CB2 3DY, UK
| | - Caren Norden
- Max Planck Institute of Molecular Cell Biology and Genetics, Pfotenhauerstraße 108, 01307 Dresden, Germany
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Barnitz RA, Chaigne-Delalande B, Bolton DL, Lenardo MJ. Exposed hydrophobic residues in human immunodeficiency virus type 1 Vpr helix-1 are important for cell cycle arrest and cell death. PLoS One 2011; 6:e24924. [PMID: 21949789 PMCID: PMC3174981 DOI: 10.1371/journal.pone.0024924] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2010] [Accepted: 08/24/2011] [Indexed: 12/28/2022] Open
Abstract
The human immunodeficiency virus type 1 (HIV-1) accessory protein viral protein R (Vpr) is a major determinant for virus-induced G2/M cell cycle arrest and cytopathicity. Vpr is thought to perform these functions through the interaction with partner proteins. The NMR structure of Vpr revealed solvent exposed hydrophobic amino acids along helices 1 and 3 of Vpr, which could be putative protein binding domains. We previously showed that the hydrophobic patch along helix-3 was important for G2/M blockade and cytopathicity. Mutations of the exposed hydrophobic residues along helix-1 were found to reduce Vpr-induced cell cycle arrest and cell death as well. The levels of toxicity during virion delivery of Vpr correlated with G2/M arrest. Thus, the exposed hydrophobic amino acids in the amino-terminal helix-1 are important for the cell cycle arrest and cytopathicity functions of Vpr.
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Affiliation(s)
- R. Anthony Barnitz
- Laboratory of Immunology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, United States of America
- Immunology Graduate Group, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Benjamin Chaigne-Delalande
- Laboratory of Immunology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Diane L. Bolton
- Laboratory of Immunology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Michael J. Lenardo
- Laboratory of Immunology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, United States of America
- Immunology Graduate Group, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
- * E-mail:
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Bogomazova AN, Lagarkova MA, Tskhovrebova LV, Shutova MV, Kiselev SL. Error-prone nonhomologous end joining repair operates in human pluripotent stem cells during late G2. Aging (Albany NY) 2011; 3:584-96. [PMID: 21685510 PMCID: PMC3164367 DOI: 10.18632/aging.100336] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Genome stability of human embryonic stem cells (hESC) is an important issue because even minor genetic alterations can negatively impact cell functionality and safety. The incorrect repair of DNA double-stranded breaks (DSBs) is the ultimate cause of the formation of chromosomal aberrations. Using G2 radiosensitivity assay, we analyzed chromosomal aberrations in pluripotent stem cells and somatic cells. The chromatid exchange aberration rates in hESCs increased manifold 2 hours after irradiation as compared with their differentiated derivatives, but the frequency of radiation-induced chromatid breaks was similar. The rate of radiation-induced chromatid exchanges in hESCs and differentiated cells exhibited a quadratic dose response, revealing two-hit mechanism of exchange formation suggesting that a non-homologous end joining (NHEJ) repair may contribute to their formation. Inhibition of DNA-PK, a key NHEJ component, by NU7026 resulted in a significant decrease in radiation-induced chromatid exchanges in hESCs but not in somatic cells. In contrast, NU7026 treatment increased the frequency of radiation-induced breaks to a similar extent in pluripotent and somatic cells. Thus, DNA-PK dependent NHEJ efficiently participates in the elimination of radiation-induced chromatid breaks during the late G2 in both cell types and DNA-PK activity leads to a high level of misrejoining specifically in pluripotent cells.
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Mir SE, De Witt Hamer PC, Krawczyk PM, Balaj L, Claes A, Niers JM, Van Tilborg AA, Zwinderman AH, Geerts D, Kaspers GJ, Vandertop WP, Cloos J, Tannous BA, Wesseling P, Aten JA, Noske DP, Van Noorden CJ, Würdinger T. In silico analysis of kinase expression identifies WEE1 as a gatekeeper against mitotic catastrophe in glioblastoma. Cancer Cell 2010; 18:244-57. [PMID: 20832752 PMCID: PMC3115571 DOI: 10.1016/j.ccr.2010.08.011] [Citation(s) in RCA: 221] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/21/2009] [Revised: 03/29/2010] [Accepted: 08/03/2010] [Indexed: 12/12/2022]
Abstract
Kinases execute pivotal cellular functions and are therefore widely investigated as potential targets in anticancer treatment. Here we analyze the kinase gene expression profiles of various tumor types and reveal the wee1 kinase to be overexpressed in glioblastomas. We demonstrate that WEE1 is a major regulator of the G(2) checkpoint in glioblastoma cells. Inhibition of WEE1 by siRNA or small molecular compound in cells exposed to DNA damaging agents results in abrogation of the G(2) arrest, premature termination of DNA repair, and cell death. Importantly, we show that the small-molecule inhibitor of WEE1 sensitizes glioblastoma to ionizing radiation in vivo. Our results suggest that inhibition of WEE1 kinase holds potential as a therapeutic approach in treatment of glioblastoma.
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Affiliation(s)
- Shahryar E. Mir
- Neuro-oncology Research Group, Departments of Neurosurgery and Pediatric Oncology/Hematology, VU University Medical Center, 1081 HV, Amsterdam, the Netherlands
| | - Philip C. De Witt Hamer
- Neuro-oncology Research Group, Departments of Neurosurgery and Pediatric Oncology/Hematology, VU University Medical Center, 1081 HV, Amsterdam, the Netherlands
| | | | - Leonora Balaj
- Neuro-oncology Research Group, Departments of Neurosurgery and Pediatric Oncology/Hematology, VU University Medical Center, 1081 HV, Amsterdam, the Netherlands
| | - An Claes
- Department of Pathology, Radboud University Nijmegen Medical Centre, 6525 GA, Nijmegen, the Netherlands
| | - Johanna M. Niers
- Neuro-oncology Research Group, Departments of Neurosurgery and Pediatric Oncology/Hematology, VU University Medical Center, 1081 HV, Amsterdam, the Netherlands
- Molecular Neurogenetics Unit, Department of Neurology, Massachusetts General Hospital and Harvard Medical School, Charlestown, MA 02113, USA
| | | | - Aeilko H. Zwinderman
- Department of Clinical Epidemiology and Biostatistics, Academic Medical Center, University of Amsterdam, 1100 DD, Amsterdam, the Netherlands
| | | | - Gertjan J.L. Kaspers
- Neuro-oncology Research Group, Departments of Neurosurgery and Pediatric Oncology/Hematology, VU University Medical Center, 1081 HV, Amsterdam, the Netherlands
| | - W. Peter Vandertop
- Neuro-oncology Research Group, Departments of Neurosurgery and Pediatric Oncology/Hematology, VU University Medical Center, 1081 HV, Amsterdam, the Netherlands
| | - Jacqueline Cloos
- Neuro-oncology Research Group, Departments of Neurosurgery and Pediatric Oncology/Hematology, VU University Medical Center, 1081 HV, Amsterdam, the Netherlands
| | - Bakhos A. Tannous
- Molecular Neurogenetics Unit, Department of Neurology, Massachusetts General Hospital and Harvard Medical School, Charlestown, MA 02113, USA
| | - Pieter Wesseling
- Department of Pathology, Radboud University Nijmegen Medical Centre, 6525 GA, Nijmegen, the Netherlands
| | | | - David P. Noske
- Neuro-oncology Research Group, Departments of Neurosurgery and Pediatric Oncology/Hematology, VU University Medical Center, 1081 HV, Amsterdam, the Netherlands
| | | | - Thomas Würdinger
- Neuro-oncology Research Group, Departments of Neurosurgery and Pediatric Oncology/Hematology, VU University Medical Center, 1081 HV, Amsterdam, the Netherlands
- Molecular Neurogenetics Unit, Department of Neurology, Massachusetts General Hospital and Harvard Medical School, Charlestown, MA 02113, USA
- Correspondence:
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Belzile JP, Abrahamyan LG, Gérard FCA, Rougeau N, Cohen ÉA. Formation of mobile chromatin-associated nuclear foci containing HIV-1 Vpr and VPRBP is critical for the induction of G2 cell cycle arrest. PLoS Pathog 2010; 6:e1001080. [PMID: 20824083 PMCID: PMC2932712 DOI: 10.1371/journal.ppat.1001080] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2010] [Accepted: 07/28/2010] [Indexed: 02/06/2023] Open
Abstract
HIV-1 Viral protein R (Vpr) induces a cell cycle arrest at the G2/M phase by activating the ATR DNA damage/stress checkpoint. Recently, we and several other groups showed that Vpr performs this activity by recruiting the DDB1-CUL4A (VPRBP) E3 ubiquitin ligase. While recruitment of this E3 ubiquitin ligase complex has been shown to be required for G2 arrest, the subcellular compartment where this complex forms and functionally acts is unknown. Herein, using immunofluorescence and confocal microscopy, we show that Vpr forms nuclear foci in several cell types including HeLa cells and primary CD4+ T-lymphocytes. These nuclear foci contain VPRBP and partially overlap with DNA repair foci components such as γ-H2AX, 53BP1 and RPA32. While treatment with the non-specific ATR inhibitor caffeine or depletion of VPRBP by siRNA did not inhibit formation of Vpr nuclear foci, mutations in the C-terminal domain of Vpr and cytoplasmic sequestration of Vpr by overexpression of Gag-Pol resulted in impaired formation of these nuclear structures and defective G2 arrest. Consistently, we observed that G2 arrest-competent sooty mangabey Vpr could form these foci but not its G2 arrest-defective paralog Vpx, suggesting that formation of Vpr nuclear foci represents a critical early event in the induction of G2 arrest. Indeed, we found that Vpr could associate to chromatin via its C-terminal domain and that it could form a complex with VPRBP on chromatin. Finally, analysis of Vpr nuclear foci by time-lapse microscopy showed that they were highly mobile and stable structures. Overall, our results suggest that Vpr recruits the DDB1-CUL4A (VPRBP) E3 ligase to these nuclear foci and uses these mobile structures to target a chromatin-bound cellular substrate for ubiquitination in order to induce DNA damage/replication stress, ultimately leading to ATR activation and G2 cell cycle arrest. HIV-1, the causative agent of AIDS, encodes several proteins termed accessory, which play a critical role in viral pathogenesis. One of these accessory proteins, viral protein R (Vpr), has been found to block normal cell division. This impairment of cell division by Vpr is thought to increase viral replication and to trigger immune cell death. However, how Vpr is able to block cell growth remains unknown. We and other investigators recently showed that Vpr was performing this activity by interacting with a cellular protein complex involved in ubiquitination. Ubiquitination is characterized by the conjugation of a small protein called ubiquitin to various other proteins to regulate their degradation or activities. In this report, we demonstrate that Vpr forms mobile punctuate structures called foci on the DNA of host cells. We also show that formation of these foci by Vpr is required to block cell division. We propose that Vpr recruits the ubiquitination complex to these nuclear foci and uses these mobile structures to target a DNA-bound cellular protein for degradation, resulting in the activation of a host cell response leading to a cell division block. Identification of the unknown cellular factor targeted by Vpr will contribute to the understanding of the role of Vpr during HIV infection and AIDS pathogenesis.
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Affiliation(s)
- Jean-Philippe Belzile
- Laboratory of Human Retrovirology, Institut de Recherches Cliniques de Montréal (IRCM), Montreal, Quebec, Canada
| | - Levon G. Abrahamyan
- Laboratory of Human Retrovirology, Institut de Recherches Cliniques de Montréal (IRCM), Montreal, Quebec, Canada
| | - Francine C. A. Gérard
- Laboratory of Human Retrovirology, Institut de Recherches Cliniques de Montréal (IRCM), Montreal, Quebec, Canada
| | - Nicole Rougeau
- Laboratory of Human Retrovirology, Institut de Recherches Cliniques de Montréal (IRCM), Montreal, Quebec, Canada
| | - Éric A. Cohen
- Laboratory of Human Retrovirology, Institut de Recherches Cliniques de Montréal (IRCM), Montreal, Quebec, Canada
- Department of Microbiology and Immunology, Université de Montréal, Montreal, Quebec, Canada
- * E-mail:
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Lee J, Jeong Y, Jeong S, Rhee K. Centrobin/NIP2 is a microtubule stabilizer whose activity is enhanced by PLK1 phosphorylation during mitosis. J Biol Chem 2010; 285:25476-84. [PMID: 20511645 PMCID: PMC2919111 DOI: 10.1074/jbc.m109.099127] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2009] [Revised: 05/24/2010] [Indexed: 11/06/2022] Open
Abstract
Centrobin/NIP2 is a centrosomal protein that is required for centrosome duplication. It is also critical for microtubule organization in both interphase and mitotic cells. In the present study, we observed that centrobin is phosphorylated in a cell cycle stage-specific manner, reaching its maximum at M phase. PLK1 is a kinase that is responsible for M phase-specific phosphorylation of centrobin. The microtubule forming activity of centrobin was enhanced by PLK1 phosphorylation. Furthermore, mitotic spindles were not assembled properly with the phospho-resistant mutant of centrobin. Based on these results, we propose that centrobin functions as a microtubule stabilizing factor and PLK1 enhances centrobin activity for proper spindle formation during mitosis.
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Affiliation(s)
- Jungmin Lee
- From the Department of Biological Sciences, Seoul National University, Seoul 151-747, Korea
| | - Yeontae Jeong
- From the Department of Biological Sciences, Seoul National University, Seoul 151-747, Korea
| | - Saimi Jeong
- From the Department of Biological Sciences, Seoul National University, Seoul 151-747, Korea
| | - Kunsoo Rhee
- From the Department of Biological Sciences, Seoul National University, Seoul 151-747, Korea
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Liu XS, Li H, Song B, Liu X. Polo-like kinase 1 phosphorylation of G2 and S-phase-expressed 1 protein is essential for p53 inactivation during G2 checkpoint recovery. EMBO Rep 2010; 11:626-32. [PMID: 20577264 PMCID: PMC2920445 DOI: 10.1038/embor.2010.90] [Citation(s) in RCA: 77] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2010] [Revised: 05/25/2010] [Accepted: 05/26/2010] [Indexed: 11/09/2022] Open
Abstract
In response to G2 DNA damage, the p53 pathway is activated to lead to cell-cycle arrest, but how p53 is eliminated during the subsequent recovery process is poorly understood. It has been established that Polo-like kinase 1 (Plk1) controls G2 DNA-damage recovery. However, whether Plk1 activity contributes to p53 inactivation during this process is unknown. In this study, we show that G2 and S-phase-expressed 1 (GTSE1) protein, a negative regulator of p53, is required for G2 checkpoint recovery and that Plk1 phosphorylation of GTSE1 at Ser 435 promotes its nuclear localization, and thus shuttles p53 out of the nucleus to lead to its degradation during the recovery.
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Affiliation(s)
- X Shawn Liu
- Department of Biochemistry, Purdue University, 175 S. University Street, West Lafayette, Indiana 47907, USA
| | - Hongchang Li
- Department of Biochemistry, Purdue University, 175 S. University Street, West Lafayette, Indiana 47907, USA
| | - Bing Song
- Department of Biological Sciences, Purdue University, 175 S. University Street, West Lafayette, Indiana 47907, USA
| | - Xiaoqi Liu
- Department of Biochemistry, Purdue University, 175 S. University Street, West Lafayette, Indiana 47907, USA
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Chang CC, Lee JJ, Chiang CW, Jayakumar T, Hsiao G, Hsieh CY, Sheu JR. Inhibitory effect of PMC, a potent hydrophilic α-tocopherol derivative, on vascular smooth muscle cell proliferation: the pivotal role of PKC-α translocation. Pharm Biol 2010; 48:938-946. [PMID: 20673182 DOI: 10.3109/13880200903305526] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
CONTENT Vascular smooth muscle cells (VSMCs) play a major role in the pathogenesis of atherosclerosis and restenosis, and thus the excessive proliferation of VSMCs contributes to neointimal thickening during atherosclerosis and restenosis. PMC (2,2,5,7,8-pentamethyl-6-hydroxychromane) is the most potent hydrophilic derivative of the alpha-tocopherols; it acts as a potent anti-inflammatory and free-radical scavenger. OBJECTIVE The present study was designed to examine the inhibitory mechanisms of PMC in VSMC proliferation. MATERIALS AND METHODS VSMC proliferation and cytotoxicity were measured by MTT and LDH assays, respectively. The cell cycle and translocation of PKC-alpha in VSMCs were used by flow cytometry and confocal microscope, respectively. To detect PKC-alpha translocation and activation in VSMCs, immunoblotting was performed in the present study. RESULTS In this study, we demonstrate an anti-proliferative effect of PMC in VSMCs. Concentration-dependent inhibition of serum-induced VSMC proliferation was observed in PMC (20 and 50 muM)-treated cells. PMC pretreatment also arrested VSMC cell cycle progression at the G2/M phase. Furthermore, PMC exhibited obvious inhibitory effects on phorbol 12-myristate 13-acetate (PMA)-induced protein kinase C (PKC)-alpha translocation and phospho-(Ser/Thr) substrate phosphorylation. DISCUSSION AND CONCLUSION The inhibitory mechanisms of PMC on VSMC proliferation is mediated, at least in part, by inhibition of PKC-alpha translocation and causes cell cycle arrest in the G2/M phase. PMC treatment may represent a novel approach for lowering the risk of or improving function in abnormal VSMC proliferation-related vascular diseases.
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MESH Headings
- Animals
- Cell Division/drug effects
- Cell Division/physiology
- Cell Proliferation/drug effects
- Cells, Cultured
- Chromans/isolation & purification
- Chromans/pharmacology
- G2 Phase/drug effects
- G2 Phase/physiology
- Muscle, Smooth, Vascular/cytology
- Muscle, Smooth, Vascular/drug effects
- Muscle, Smooth, Vascular/enzymology
- Myocytes, Smooth Muscle/cytology
- Myocytes, Smooth Muscle/drug effects
- Myocytes, Smooth Muscle/enzymology
- Protein Kinase C-alpha/antagonists & inhibitors
- Protein Kinase C-alpha/metabolism
- Protein Kinase C-alpha/physiology
- Protein Transport/drug effects
- Protein Transport/physiology
- Rats
- Rats, Wistar
- alpha-Tocopherol/isolation & purification
- alpha-Tocopherol/pharmacology
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Ramírez-Valle F, Badura ML, Braunstein S, Narasimhan M, Schneider RJ. Mitotic raptor promotes mTORC1 activity, G(2)/M cell cycle progression, and internal ribosome entry site-mediated mRNA translation. Mol Cell Biol 2010; 30:3151-64. [PMID: 20439490 PMCID: PMC2897579 DOI: 10.1128/mcb.00322-09] [Citation(s) in RCA: 77] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2009] [Revised: 04/21/2009] [Accepted: 04/26/2010] [Indexed: 01/17/2023] Open
Abstract
The mTOR signaling complex integrates signals from growth factors and nutrient availability to control cell growth and proliferation, in part through effects on the protein-synthetic machinery. Protein synthesis rates fluctuate throughout the cell cycle but diminish significantly during the G(2)/M transition. The fate of the mTOR complex and its role in coordinating cell growth and proliferation signals with protein synthesis during mitosis remain unknown. Here we demonstrate that the mTOR complex 1 (mTORC1) pathway, which stimulates protein synthesis, is actually hyperactive during mitosis despite decreased protein synthesis and reduced activity of mTORC1 upstream activators. We describe previously unknown G(2)/M-specific phosphorylation of a component of mTORC1, the protein raptor, and demonstrate that mitotic raptor phosphorylation alters mTORC1 function during mitosis. Phosphopeptide mapping and mutational analysis demonstrate that mitotic phosphorylation of raptor facilitates cell cycle transit through G(2)/M. Phosphorylation-deficient mutants of raptor cause cells to delay in G(2)/M, whereas depletion of raptor causes cells to accumulate in G(1). We identify cyclin-dependent kinase 1 (cdk1 [cdc2]) and glycogen synthase kinase 3 (GSK3) pathways as two probable mitosis-regulated protein kinase pathways involved in mitosis-specific raptor phosphorylation and altered mTORC1 activity. In addition, mitotic raptor promotes translation by internal ribosome entry sites (IRES) on mRNA during mitosis and is demonstrated to be associated with rapamycin resistance. These data suggest that this pathway may play a role in increased IRES-dependent mRNA translation during mitosis and in rapamycin insensitivity.
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Affiliation(s)
- Francisco Ramírez-Valle
- Department of Microbiology and NYU Cancer Institute, New York University School of Medicine, New York, New York 10016
| | - Michelle L. Badura
- Department of Microbiology and NYU Cancer Institute, New York University School of Medicine, New York, New York 10016
| | - Steve Braunstein
- Department of Microbiology and NYU Cancer Institute, New York University School of Medicine, New York, New York 10016
| | - Manisha Narasimhan
- Department of Microbiology and NYU Cancer Institute, New York University School of Medicine, New York, New York 10016
| | - Robert J. Schneider
- Department of Microbiology and NYU Cancer Institute, New York University School of Medicine, New York, New York 10016
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Plate M, Li T, Wang Y, Mo X, Zhang Y, Ma D, Han W. Identification and characterization of CMTM4, a novel gene with inhibitory effects on HeLa cell growth through Inducing G2/M phase accumulation. Mol Cells 2010; 29:355-61. [PMID: 20213316 DOI: 10.1007/s10059-010-0038-7] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2009] [Revised: 12/06/2009] [Accepted: 12/07/2009] [Indexed: 10/19/2022] Open
Abstract
Human CMTM is a novel gene family consisting of CKLF and CMTM1-8. CMTM4 is the most conserved gene and has three RNA splicing forms designated as CMTM4-v1, -v2 and -v3, but in many types of tissue and cell lines, only CMTM4-v1 and -v2 could be detected. CMTM4-v2 is the full length cDNA product, which has been highly conserved during evolution. CMTM4-v1 and -v2 are broadly expressed in normal types of tissue. They are distributed on the cell membrane and across the cytoplasm in a speckled pattern. Overexpression of CMTM4-v1 and -v2 can inhibit HeLa cell growth via G2/M phase accumulation without inducing apoptosis. Therefore, CMTM4 might be an important gene involved in cell growth and cell cycle regulation.
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Affiliation(s)
- Markus Plate
- Center for Human Disease Genomics, Department of Immunology, School of Basic Medical Science, Health Science Center, Peking University, Beijing, 100191, China
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Kim JA, Lee J, Margolis RL, Fotedar R. SP600125 suppresses Cdk1 and induces endoreplication directly from G2 phase, independent of JNK inhibition. Oncogene 2010; 29:1702-16. [PMID: 20062077 PMCID: PMC3145494 DOI: 10.1038/onc.2009.464] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2009] [Revised: 10/14/2009] [Accepted: 10/22/2009] [Indexed: 12/20/2022]
Abstract
Cell cycle controls ensure that DNA replication (S phase) follows mitosis resulting in two precise copies of the genome. A failure of the control mechanisms can result in multiple rounds of DNA replication without cell division. In endoreplication, cells with replicated genomes bypass mitosis, then replicate their DNA again, resulting in polyploidy. Endoreplication from G2 phase lacks all hallmarks of mitosis. Using synchronized cells, we show that the c-Jun N-terminal kinase (JNK) inhibitor, SP600125, prevents the entry of cells into mitosis and leads to endoreplication of DNA from G2 phase. We show that cells proceed from G2 phase to replicate their DNA in the absence of mitosis. This effect of SP600125 is independent of its suppression of JNK activity. Instead, the inhibitory effect of SP600125 on mitotic entry predominantly occurs upstream of Aurora A kinase and Polo-like kinase 1, resulting in a failure to remove the inhibitory phosphorylation of Cdk1. Importantly, our results directly show that the inhibition of Cdk1 activity and the persistence of Cdk2 activity in G2 cells induces endoreplication without mitosis. Furthermore, endoreplication from G2 phase is independent of p53 control.
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Affiliation(s)
- JA Kim
- Sidney Kimmel Cancer Center, San Diego, CA, USA
| | - J Lee
- Sidney Kimmel Cancer Center, San Diego, CA, USA
| | - RL Margolis
- Sidney Kimmel Cancer Center, San Diego, CA, USA
- Burnham Institute for Medical Research, La Jolla, CA, USA
| | - R Fotedar
- Sidney Kimmel Cancer Center, San Diego, CA, USA
- Burnham Institute for Medical Research, La Jolla, CA, USA
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van Vugt MATM, Gardino AK, Linding R, Ostheimer GJ, Reinhardt HC, Ong SE, Tan CS, Miao H, Keezer SM, Li J, Pawson T, Lewis TA, Carr SA, Smerdon SJ, Brummelkamp TR, Yaffe MB. A mitotic phosphorylation feedback network connects Cdk1, Plk1, 53BP1, and Chk2 to inactivate the G(2)/M DNA damage checkpoint. PLoS Biol 2010; 8:e1000287. [PMID: 20126263 PMCID: PMC2811157 DOI: 10.1371/journal.pbio.1000287] [Citation(s) in RCA: 175] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2009] [Accepted: 12/11/2009] [Indexed: 12/18/2022] Open
Abstract
DNA damage checkpoints arrest cell cycle progression to facilitate DNA repair. The ability to survive genotoxic insults depends not only on the initiation of cell cycle checkpoints but also on checkpoint maintenance. While activation of DNA damage checkpoints has been studied extensively, molecular mechanisms involved in sustaining and ultimately inactivating cell cycle checkpoints are largely unknown. Here, we explored feedback mechanisms that control the maintenance and termination of checkpoint function by computationally identifying an evolutionary conserved mitotic phosphorylation network within the DNA damage response. We demonstrate that the non-enzymatic checkpoint adaptor protein 53BP1 is an in vivo target of the cell cycle kinases Cyclin-dependent kinase-1 and Polo-like kinase-1 (Plk1). We show that Plk1 binds 53BP1 during mitosis and that this interaction is required for proper inactivation of the DNA damage checkpoint. 53BP1 mutants that are unable to bind Plk1 fail to restart the cell cycle after ionizing radiation-mediated cell cycle arrest. Importantly, we show that Plk1 also phosphorylates the 53BP1-binding checkpoint kinase Chk2 to inactivate its FHA domain and inhibit its kinase activity in mammalian cells. Thus, a mitotic kinase-mediated negative feedback loop regulates the ATM-Chk2 branch of the DNA damage signaling network by phosphorylating conserved sites in 53BP1 and Chk2 to inactivate checkpoint signaling and control checkpoint duration.
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Affiliation(s)
- Marcel A. T. M. van Vugt
- David H. Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, Massachusetts, United States of America
| | - Alexandra K. Gardino
- David H. Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, Massachusetts, United States of America
| | - Rune Linding
- Cellular and Molecular Logic Team Integrative Network Biology initiative (INBi) Section of Cell and Molecular Biology, The Institute of Cancer Research, London, United Kingdom
| | - Gerard J. Ostheimer
- David H. Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, Massachusetts, United States of America
- Departments of Biological Engineering and Biology, Massachusetts Institute of Technology, Cambridge, Massachusetts, United States of America
| | - H. Christian Reinhardt
- David H. Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, Massachusetts, United States of America
| | - Shao-En Ong
- Broad Institute of Harvard and MIT, Cambridge, Massachusetts, United States of America
| | - Chris S. Tan
- Samuel Lunenfeld Research Institute, Mount Sinai Hospital, Toronto, Canada
| | - Hua Miao
- Broad Institute of Harvard and MIT, Cambridge, Massachusetts, United States of America
| | - Susan M. Keezer
- Cell Signaling Technologies, Danvers, Massachusetts, United States of America
| | - Jeijin Li
- Division of Molecular Structure, Medical Research Council (MRC) National Institute for Medical Research, London, United Kingdom
| | - Tony Pawson
- Broad Institute of Harvard and MIT, Cambridge, Massachusetts, United States of America
| | - Timothy A. Lewis
- Broad Institute of Harvard and MIT, Cambridge, Massachusetts, United States of America
| | - Steven A. Carr
- Broad Institute of Harvard and MIT, Cambridge, Massachusetts, United States of America
| | - Stephen J. Smerdon
- Division of Molecular Structure, Medical Research Council (MRC) National Institute for Medical Research, London, United Kingdom
| | - Thijn R. Brummelkamp
- Whitehead Institute, Massachusetts Institute of Technology, Cambridge, Massachusetts, United States of America
| | - Michael B. Yaffe
- David H. Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, Massachusetts, United States of America
- Departments of Biological Engineering and Biology, Massachusetts Institute of Technology, Cambridge, Massachusetts, United States of America
- Broad Institute of Harvard and MIT, Cambridge, Massachusetts, United States of America
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48
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Tang L, Zhang Y, Pan H, Luo Q, Zhu XM, Dong MY, Leung PCK, Sheng JZ, Huang HF. Involvement of cyclin B1 in progesterone-mediated cell growth inhibition, G2/M cell cycle arrest, and apoptosis in human endometrial cell. Reprod Biol Endocrinol 2009; 7:144. [PMID: 19968870 PMCID: PMC2797512 DOI: 10.1186/1477-7827-7-144] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/16/2009] [Accepted: 12/07/2009] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Progesterone plays an important role in the proliferation and differentiation of human endometrial cells (hECs). Large-dose treatment with progesterone has been used for treatment of endometrial proliferative disorders. However, the mechanisms behind remain unknown. METHODS To investigate the role of cyclin B1 in proliferation and differentiation of hECs in menstrual cycle, the expression of cyclin B1 throughout the menstrual cycle was evaluated in hECs. To determine the effects of progesterone on the proliferation, cell cycle progression and apoptosis of hECs and to test if cyclin B1 is involved in these effects, progesterone and/or Alsterpaullone (Alp, a specific inhibitor of Cyclin B1/Cdc2) were added to primary hECs. Cellular proliferation was evaluated with MTT test, cell cycle with propidium iodide (PI) staining and flow cytometry, apoptosis with FITC-Annexin V and the expression of cyclin B1 with Western blotting. RESULTS The expression level of cyclin B1 in secretory endometria was significantly lower than in proliferative endometria (p < 0.01). Progesterone significantly inhibited the growth of hECs in a concentration-dependent manner (P < 0.01). The treatment with progesterone significantly decreased the expression of cyclin B1, increased the proportions of cell in G2/M phase, and apoptotic cells (P < 0.05 for all). The presence of Alp significantly enhanced the effects of progesterone on cyclin B1 down-regulation, G2/M cell cycle arrest and induction of apoptosis (P < 0.01 for all). CONCLUSION Our findings suggest that cyclin B1 is a critical factor in proliferation and differentiation of hECs. Progesterone may inhibit cell proliferation, mediate G2/M cell cycle arrest and induce apoptosis in hECs via down-regulating Cyclin B1.
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Affiliation(s)
- Li Tang
- Department of Reproductive Endocrinology, Women's Hospital, School of Medicine, Zhejiang University, Hangzhou, China
- Department of Reproductive Endocrinology, The First People's Hospital of Yunnan Province, Yunnan, China
| | - Yu Zhang
- Department of Reproductive Endocrinology, Women's Hospital, School of Medicine, Zhejiang University, Hangzhou, China
| | - Hong Pan
- Department of Reproductive Endocrinology, Women's Hospital, School of Medicine, Zhejiang University, Hangzhou, China
| | - Qiong Luo
- Department of Reproductive Endocrinology, Women's Hospital, School of Medicine, Zhejiang University, Hangzhou, China
| | - Xiao-Ming Zhu
- Department of Reproductive Endocrinology, Women's Hospital, School of Medicine, Zhejiang University, Hangzhou, China
| | - Min-Yue Dong
- Department of Reproductive Endocrinology, Women's Hospital, School of Medicine, Zhejiang University, Hangzhou, China
| | - Peter CK Leung
- Department of Obstetrics and Gynaecology, Child and Family Research Institute, University of British Columbia, Vancouver, British Columbia V6H 3V5, Canada
| | - Jian-Zhong Sheng
- Department of Pathology and Pathophysiology, School of Medicine, Zhejiang University, Hangzhou, China
| | - He-Feng Huang
- Department of Reproductive Endocrinology, Women's Hospital, School of Medicine, Zhejiang University, Hangzhou, China
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Browaeys-Poly E, Perdereau D, Lescuyer A, Burnol AF, Cailliau K. Akt interaction with PLC(gamma) regulates the G(2)/M transition triggered by FGF receptors from MDA-MB-231 breast cancer cells. Anticancer Res 2009; 29:4965-4969. [PMID: 20044603] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
BACKGROUND/AIM Estrogen-independent breast cancer cell growth is under the control of fibroblast growth factors receptors (FGFRs), but the role of phospholipase C gamma (PLC(gamma)) and Akt, the downstream effectors activated by FGFRs, in cell proliferation is still unresolved. MATERIALS AND METHODS FGFRs from highly invasive MDA-MB-231 cells were expressed in Xenopus oocyte, a powerful model system to assess the G(2)/M checkpoint regulation. Under FGF1 stimulation, an analysis of the progression in the M-phase of the cell cycle and of the Akt signaling cascades were performed using the phosphatidylinositol-3-kinase inhibitor, LY294002, and a mimetic peptide of the SH3 domain of PLC(gamma). RESULTS Activated Akt binds and phosphorylates PLC(gamma) before Akt targets the tumor suppressor Chfr. Disruption of the Akt-PLC(gamma) interaction directs Akt binding to Chfr and accelerates the alleviation of the G(2)/M checkpoint. CONCLUSION The PLC(gamma)-Akt interaction, triggered by FGF receptors from estrogen-independent breast cancer cells MDA-MB-231, regulates progression in the M-phase of the cell cycle.
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Affiliation(s)
- Edith Browaeys-Poly
- Laboratoire de Régulation des Signaux de Division, Université Lille 1 Sciences et Technologies, 59655 Villeneuve d'Ascq, France
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Schmit TL, Zhong W, Setaluri V, Spiegelman VS, Ahmad N. Targeted depletion of Polo-like kinase (Plk) 1 through lentiviral shRNA or a small-molecule inhibitor causes mitotic catastrophe and induction of apoptosis in human melanoma cells. J Invest Dermatol 2009; 129:2843-53. [PMID: 19554017 PMCID: PMC2799787 DOI: 10.1038/jid.2009.172] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Melanoma, one of the most lethal forms of skin cancer, remains resistant to currently available treatments. Therefore, additional target-based approaches are needed for the management of this neoplasm. Polo-like kinase 1 (Plk1) has been shown to be a crucial regulator of mitotic entry, progression, and exit. Elevated Plk1 level has been associated with aggressiveness of several cancer types and with poor disease prognosis. However, the role of Plk1 in melanoma is not well established. Here, we show that Plk1 is overexpressed in both clinical tissue specimens and cultured human melanoma cells (WM115, A375, and HS294T) when compared with normal skin tissues and cultured normal melanocytes, respectively. Furthermore, Plk1 gene knockdown through Plk1-specific shRNA or its activity inhibition by a small-molecule inhibitor resulted in a significant decrease in the viability and growth of melanoma cells without affecting normal human melanocytes. In addition, Plk1 inhibition resulted in a significant (i) decrease in clonogenic survival, (ii) multiple mitotic errors, (iii) G(2)/M cell-cycle arrest, and (iv) apoptosis of melanoma cells. This study suggests that Plk1 may have a functional relevance toward melanoma development and/or progression. We suggest that the targeting of Plk1 may be a viable approach for the treatment of melanoma.
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Affiliation(s)
- Travis L. Schmit
- Department of Dermatology, University of Wisconsin, Madison, WI
- Molecular and Environmental Toxicology Center, University of Wisconsin, Madison, WI
| | - Weixiong Zhong
- Department of Pathology and Laboratory Medicine, University of Wisconsin, Madison, WI
- University of Wisconsin Paul P. Carbone Comprehensive Cancer Center; University of Wisconsin, Madison, WI
| | - Vijayasaradhi Setaluri
- Department of Dermatology, University of Wisconsin, Madison, WI
- Molecular and Environmental Toxicology Center, University of Wisconsin, Madison, WI
- University of Wisconsin Paul P. Carbone Comprehensive Cancer Center; University of Wisconsin, Madison, WI
| | - Vladimir S. Spiegelman
- Department of Dermatology, University of Wisconsin, Madison, WI
- Molecular and Environmental Toxicology Center, University of Wisconsin, Madison, WI
- University of Wisconsin Paul P. Carbone Comprehensive Cancer Center; University of Wisconsin, Madison, WI
| | - Nihal Ahmad
- Department of Dermatology, University of Wisconsin, Madison, WI
- Molecular and Environmental Toxicology Center, University of Wisconsin, Madison, WI
- University of Wisconsin Paul P. Carbone Comprehensive Cancer Center; University of Wisconsin, Madison, WI
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