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Qi K, Hu X, Yu X, Cheng H, Wang C, Wang S, Wang Y, Li Y, Cao J, Pan B, Wu Q, Qiao J, Zeng L, Li Z, Xu K, Fu C. Targeting cyclin-dependent kinases 4/6 inhibits survival of megakaryoblasts in acute megakaryoblastic leukaemia. Leuk Res 2022; 120:106920. [PMID: 35872339 DOI: 10.1016/j.leukres.2022.106920] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2022] [Revised: 06/19/2022] [Accepted: 07/16/2022] [Indexed: 11/16/2022]
Abstract
Acute megakaryoblastic leukaemia (AMKL) is characterized by expansion of megakaryoblasts, which are hyper-proliferative cells that fail to undergo differentiation. Insight to the cell-cycle regulation revealed important events in early or late megakaryocytes (MKs) maturation; the cyclin-dependent kinases 4 and 6 (CDK4/6) have been reported to participate in the development of progenitor megakaryocytes, mainly by promoting cell cycle progression and DNA polyploidization. However, it remains unclear whether the continuous proliferation, but not differentiation, of megakaryoblasts is related to an aberrant regulation of CDK4/6 in AMKL. Here, we found that CDK4/6 were up regulated in patients with AMKL, and persistently maintained at a high level during the differentiation of abnormal megakaryocytes in vitro, according to a database and western blot. Additionally, AMKL cells were exceptionally reliant on the cell cycle regulators CDK4 or 6, as blocking their activity using an inhibitor or short hairpin RNA (shRNA) significantly reduced the proliferation of 6133/MPL megakaryocytes, reduced DNA polyploidy, induced apoptosis, decreased the level of phosphorylated retinoblastoma protein (p-Rb), and activation of caspase 3. Additionally, CDK4/6 inhibitors and shRNA reduced the numbers of leukemia cells in the liver and bone marrow (BM), alleviated hepatosplenomegaly, and prolonged the survival of AMKL-transplanted mice. These results suggested that blocking the activity of CDK4/6 may represent an effective approach to control megakaryoblasts in AMKL.
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Affiliation(s)
- Kunming Qi
- Blood Diseases Institute, Xuzhou Medical University, Xuzhou, China; Department of Hematology, The Affiliated Hospital of Xuzhou Medical University, Xuzhou, China; Key Laboratory of Bone Marrow Stem Cell, Jiangsu Province, Xuzhou, China
| | - Xueting Hu
- Blood Diseases Institute, Xuzhou Medical University, Xuzhou, China
| | - Xiangru Yu
- Blood Diseases Institute, Xuzhou Medical University, Xuzhou, China
| | - Hai Cheng
- Blood Diseases Institute, Xuzhou Medical University, Xuzhou, China; Department of Hematology, The Affiliated Hospital of Xuzhou Medical University, Xuzhou, China; Key Laboratory of Bone Marrow Stem Cell, Jiangsu Province, Xuzhou, China
| | - Chunqing Wang
- Blood Diseases Institute, Xuzhou Medical University, Xuzhou, China; Department of Hematology, The Affiliated Hospital of Xuzhou Medical University, Xuzhou, China
| | - Shujin Wang
- Blood Diseases Institute, Xuzhou Medical University, Xuzhou, China
| | - Ying Wang
- Blood Diseases Institute, Xuzhou Medical University, Xuzhou, China; Department of Hematology, The Affiliated Hospital of Xuzhou Medical University, Xuzhou, China; Key Laboratory of Bone Marrow Stem Cell, Jiangsu Province, Xuzhou, China
| | - Yanjie Li
- Blood Diseases Institute, Xuzhou Medical University, Xuzhou, China
| | - Jiang Cao
- Blood Diseases Institute, Xuzhou Medical University, Xuzhou, China; Department of Hematology, The Affiliated Hospital of Xuzhou Medical University, Xuzhou, China; Key Laboratory of Bone Marrow Stem Cell, Jiangsu Province, Xuzhou, China
| | - Bin Pan
- Blood Diseases Institute, Xuzhou Medical University, Xuzhou, China; Department of Hematology, The Affiliated Hospital of Xuzhou Medical University, Xuzhou, China; Key Laboratory of Bone Marrow Stem Cell, Jiangsu Province, Xuzhou, China
| | - Qingyun Wu
- Blood Diseases Institute, Xuzhou Medical University, Xuzhou, China; Department of Hematology, The Affiliated Hospital of Xuzhou Medical University, Xuzhou, China; Key Laboratory of Bone Marrow Stem Cell, Jiangsu Province, Xuzhou, China
| | - Jianlin Qiao
- Blood Diseases Institute, Xuzhou Medical University, Xuzhou, China; Department of Hematology, The Affiliated Hospital of Xuzhou Medical University, Xuzhou, China; Key Laboratory of Bone Marrow Stem Cell, Jiangsu Province, Xuzhou, China
| | - Lingyu Zeng
- Blood Diseases Institute, Xuzhou Medical University, Xuzhou, China; Department of Hematology, The Affiliated Hospital of Xuzhou Medical University, Xuzhou, China; Key Laboratory of Bone Marrow Stem Cell, Jiangsu Province, Xuzhou, China
| | - Zhenyu Li
- Blood Diseases Institute, Xuzhou Medical University, Xuzhou, China; Department of Hematology, The Affiliated Hospital of Xuzhou Medical University, Xuzhou, China; Key Laboratory of Bone Marrow Stem Cell, Jiangsu Province, Xuzhou, China
| | - Kailin Xu
- Blood Diseases Institute, Xuzhou Medical University, Xuzhou, China; Department of Hematology, The Affiliated Hospital of Xuzhou Medical University, Xuzhou, China; Key Laboratory of Bone Marrow Stem Cell, Jiangsu Province, Xuzhou, China.
| | - Chunling Fu
- Blood Diseases Institute, Xuzhou Medical University, Xuzhou, China; Department of Hematology, The Affiliated Hospital of Xuzhou Medical University, Xuzhou, China; Key Laboratory of Bone Marrow Stem Cell, Jiangsu Province, Xuzhou, China.
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VanGenderen C, Harkness TAA, Arnason TG. The role of Anaphase Promoting Complex activation, inhibition and substrates in cancer development and progression. Aging (Albany NY) 2020; 12:15818-15855. [PMID: 32805721 PMCID: PMC7467358 DOI: 10.18632/aging.103792] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2020] [Accepted: 07/14/2020] [Indexed: 02/07/2023]
Abstract
The Anaphase Promoting Complex (APC), a multi-subunit ubiquitin ligase, facilitates mitotic and G1 progression, and is now recognized to play a role in maintaining genomic stability. Many APC substrates have been observed overexpressed in multiple cancer types, such as CDC20, the Aurora A and B kinases, and Forkhead box M1 (FOXM1), suggesting APC activity is important for cell health. We performed BioGRID analyses of the APC coactivators CDC20 and CDH1, which revealed that at least 69 proteins serve as APC substrates, with 60 of them identified as playing a role in tumor promotion and 9 involved in tumor suppression. While these substrates and their association with malignancies have been studied in isolation, the possibility exists that generalized APC dysfunction could result in the inappropriate stabilization of multiple APC targets, thereby changing tumor behavior and treatment responsiveness. It is also possible that the APC itself plays a crucial role in tumorigenesis through its regulation of mitotic progression. In this review the connections between APC activity and dysregulation will be discussed with regards to cell cycle dysfunction and chromosome instability in cancer, along with the individual roles that the accumulation of various APC substrates may play in cancer progression.
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Affiliation(s)
- Cordell VanGenderen
- Department of Anatomy, Physiology and Pharmacology, University of Saskatchewan, Saskatoon, SK S7N 5E5, Canada
| | - Troy Anthony Alan Harkness
- Department of Biochemistry, Microbiology and Immunology, University of Saskatchewan, Saskatoon, SK S7N 5E5, Canada
| | - Terra Gayle Arnason
- Department of Medicine, University of Saskatchewan, Saskatoon, SK S7N 5E5, Canada.,Department of Anatomy, Physiology and Pharmacology, University of Saskatchewan, Saskatoon, SK S7N 5E5, Canada
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Noetzli LJ, French SL, Machlus KR. New Insights Into the Differentiation of Megakaryocytes From Hematopoietic Progenitors. Arterioscler Thromb Vasc Biol 2019; 39:1288-1300. [PMID: 31043076 PMCID: PMC6594866 DOI: 10.1161/atvbaha.119.312129] [Citation(s) in RCA: 140] [Impact Index Per Article: 28.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2019] [Accepted: 04/22/2019] [Indexed: 02/07/2023]
Abstract
Megakaryocytes are hematopoietic cells, which are responsible for the production of blood platelets. The traditional view of megakaryopoiesis describes the cellular journey from hematopoietic stem cells, through a hierarchical series of progenitor cells, ultimately to a mature megakaryocyte. Once mature, the megakaryocyte then undergoes a terminal maturation process involving multiple rounds of endomitosis and cytoplasmic restructuring to allow platelet formation. However, recent studies have begun to redefine this hierarchy and shed new light on alternative routes by which hematopoietic stem cells are differentiated into megakaryocytes. In particular, the origin of megakaryocytes, including the existence and hierarchy of megakaryocyte progenitors, has been redefined, as new studies are suggesting that hematopoietic stem cells originate as megakaryocyte-primed and can bypass traditional lineage checkpoints. Overall, it is becoming evident that megakaryopoiesis does not only occur as a stepwise process, but is dynamic and adaptive to biological needs. In this review, we will reexamine the canonical dogmas of megakaryopoiesis and provide an updated framework for interpreting the roles of traditional pathways in the context of new megakaryocyte biology. Visual Overview- An online visual overview is available for this article.
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Affiliation(s)
- Leila J Noetzli
- Division of Hematology, Brigham and Women’s Hospital and Department of Medicine, Harvard Medical School, Boston, MA, 02115, USA
| | - Shauna L French
- Division of Hematology, Brigham and Women’s Hospital and Department of Medicine, Harvard Medical School, Boston, MA, 02115, USA
| | - Kellie R Machlus
- Division of Hematology, Brigham and Women’s Hospital and Department of Medicine, Harvard Medical School, Boston, MA, 02115, USA
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Mok MT, Zhou J, Tang W, Zeng X, Oliver AW, Ward SE, Cheng AS. CCRK is a novel signalling hub exploitable in cancer immunotherapy. Pharmacol Ther 2018; 186:138-151. [PMID: 29360538 DOI: 10.1016/j.pharmthera.2018.01.008] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Cyclin-dependent kinase 20 (CDK20), or more commonly referred to as cell cycle-related kinase (CCRK), is the latest member of CDK family with strong linkage to human cancers. Accumulating studies have reported the consistent overexpression of CCRK in cancers arising from brain, colon, liver, lung and ovary. Such aberrant up-regulation of CCRK is clinically significant as it correlates with tumor staging, shorter patient survival and poor prognosis. Intriguingly, the signalling molecules perturbed by CCRK are divergent and cancer-specific, including the cell cycle regulators CDK2, cyclin D1, cyclin E and RB in glioblastoma, ovarian carcinoma and colorectal cancer, and KEAP1-NRF2 cytoprotective pathway in lung cancer. In hepatocellular carcinoma (HCC), CCRK mediates virus-host interaction to promote hepatitis B virus-associated tumorigenesis. Further mechanistic analyses reveal that CCRK orchestrates a self-reinforcing circuitry comprising of AR, GSK3β, β-catenin, AKT, EZH2, and NF-κB signalling for transcriptional and epigenetic regulation of oncogenes and tumor suppressor genes. Notably, EZH2 and NF-κB in this circuit have been recently shown to induce IL-6 production to facilitate tumor immune evasion. Concordantly, in a hepatoma preclinical model, ablation of Ccrk disrupts the immunosuppressive tumor microenvironment and enhances the therapeutic efficacy of immune checkpoint blockade via potentiation of anti-tumor T cell responses. In this review, we summarized the multifaceted tumor-intrinsic and -extrinsic functions of CCRK, which represents a novel signalling hub exploitable in cancer immunotherapy.
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Affiliation(s)
- Myth T Mok
- School of Biomedical Sciences, The Chinese University of Hong Kong, Hong Kong, China
| | - Jingying Zhou
- School of Biomedical Sciences, The Chinese University of Hong Kong, Hong Kong, China
| | - Wenshu Tang
- School of Biomedical Sciences, The Chinese University of Hong Kong, Hong Kong, China
| | - Xuezhen Zeng
- School of Biomedical Sciences, The Chinese University of Hong Kong, Hong Kong, China
| | - Antony W Oliver
- Genome Damage and Stability Centre, School of Life Sciences, University of Sussex, Falmer, UK
| | - Simon E Ward
- Medicines Discovery Institute, Cardiff University, Main Building, Cardiff, Wales, CF10 3AT, UK
| | - Alfred S Cheng
- School of Biomedical Sciences, The Chinese University of Hong Kong, Hong Kong, China; State Key Laboratory of Digestive Disease, The Chinese University of Hong Kong, Hong Kong, China.
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Small Molecule Supplements Improve Cultured Megakaryocyte Polyploidization by Modulating Multiple Cell Cycle Regulators. BIOMED RESEARCH INTERNATIONAL 2017; 2017:2320519. [PMID: 29201898 PMCID: PMC5671672 DOI: 10.1155/2017/2320519] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/05/2017] [Accepted: 09/07/2017] [Indexed: 01/06/2023]
Abstract
Platelets (PLTs) are produced by megakaryocytes (MKs) that completed differentiation and endomitosis. Endomitosis is an important process in which the cell replicates its DNA without cytokinesis and develops highly polyploid MK. In this study, to gain a better PLTs production, four small molecules (Rho-Rock inhibitor (RRI), nicotinamide (NIC), Src inhibitor (SI), and Aurora B inhibitor (ABI)) and their combinations were surveyed as MK culture supplements for promoting polyploidization. Three leukemia cell lines as well as primary mononuclear cells were chosen in the function and mechanism studies of the small molecules. In an optimal culture method, cells were treated with different small molecules and their combinations. The impact of the small molecules on megakaryocytic surface marker expression, polyploidy, proliferation, and apoptosis was examined for the best MK polyploidization supplement. The elaborate analysis confirmed that the combination of SI and RRI together with our MK induction system might result in efficient ploidy promotion. Our experiments demonstrated that, besides direct downregulation on the expression of cytoskeleton protein actin, SI and RRI could significantly enhance the level of cyclins through the suppression of p53 and p21. The verified small molecule combination might be further used in the in vitro PLT manufacture and clinical applications.
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Lin Z, Tan C, Qiu Q, Kong S, Yang H, Zhao F, Liu Z, Li J, Kong Q, Gao B, Barrett T, Yang GY, Zhang J, Fang D. Ubiquitin-specific protease 22 is a deubiquitinase of CCNB1. Cell Discov 2015; 1. [PMID: 27030811 PMCID: PMC4809424 DOI: 10.1038/celldisc.2015.28] [Citation(s) in RCA: 48] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
The elevated level of CCNB1 indicates more aggressive cancer and poor prognosis. However, the factors that cause CCNB1 upregulation remain enigmatic. Herein, we identify USP22 as a CCNB1 interactor and discover that both USP22 and CCNB1 are dramatically elevated with a strong positive correlation in colon cancer tissues. USP22 stabilizes CCNB1 by antagonizing proteasome-mediated degradation in a cell cycle-specific manner. Phosphorylation of USP22 by CDK1 enhances its activity in deubiquitinating CCNB1. The ubiquitin ligase anaphase-promoting complex (APC/C) targets USP22 for degradation by using the substrate adapter CDC20 during cell exit from M phase, presumably allowing CCNB1 degradation. Finally, we discover that USP22 knockdown leads to slower cell growth and reduced tumor size. Our study demonstrates that USP22 is a CCNB1 deubiquitinase, suggesting that targeting USP22 might be an effective approach to treat cancers with elevated CCNB1 expression.
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Affiliation(s)
- Zhenghong Lin
- Department of Pathology, Northwestern University Feinberg School of Medicine, Chicago, IL, USA
| | - Can Tan
- Department of Pathology, Northwestern University Feinberg School of Medicine, Chicago, IL, USA
| | - Quan Qiu
- Department of Pathology, Northwestern University Feinberg School of Medicine, Chicago, IL, USA
| | - Sinyi Kong
- Department of Pathology, Northwestern University Feinberg School of Medicine, Chicago, IL, USA
| | - Heeyoung Yang
- Department of Pathology, Northwestern University Feinberg School of Medicine, Chicago, IL, USA
| | - Fang Zhao
- Department of Pathology, Northwestern University Feinberg School of Medicine, Chicago, IL, USA
| | - Zhaojian Liu
- Department of Pathology, Northwestern University Feinberg School of Medicine, Chicago, IL, USA
| | - Jinping Li
- Department of Pathology, Northwestern University Feinberg School of Medicine, Chicago, IL, USA
| | - Qingfei Kong
- Department of Pathology, Northwestern University Feinberg School of Medicine, Chicago, IL, USA
| | - Beixue Gao
- Department of Pathology, Northwestern University Feinberg School of Medicine, Chicago, IL, USA
| | - Terry Barrett
- Department of Medicine, Northwestern University Feinberg School of Medicine, Chicago, IL, USA
| | - Guang-Yu Yang
- Department of Pathology, Northwestern University Feinberg School of Medicine, Chicago, IL, USA
| | - Jianing Zhang
- School of Life Science and Medicine, Dalian University of Technology, Panjin, China
| | - Deyu Fang
- Department of Pathology, Northwestern University Feinberg School of Medicine, Chicago, IL, USA; School of Life Science and Medicine, Dalian University of Technology, Panjin, China
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Neganova I, Tilgner K, Buskin A, Paraskevopoulou I, Atkinson SP, Peberdy D, Passos JF, Lako M. CDK1 plays an important role in the maintenance of pluripotency and genomic stability in human pluripotent stem cells. Cell Death Dis 2014; 5:e1508. [PMID: 25375373 PMCID: PMC4260724 DOI: 10.1038/cddis.2014.464] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2014] [Revised: 09/16/2014] [Accepted: 09/24/2014] [Indexed: 12/12/2022]
Abstract
Human embryonic stem cells (hESC) and induced pluripotent stem cells (hiPSC) are characterised by an unusual and tightly regulated cell cycle that has been shown to be important for the maintenance of a pluripotent phenotype. Cyclin-dependant kinase 1 (CDK1) is a key player in cell cycle regulation and particularly mitosis; however, its role has not been studied previously in hESC and hiPSC. To investigate the impacts of CDK1 downregulation, we performed RNA interference studies which in addition to expected mitotic deficiencies revealed a large range of additional phenotypes related to maintenance of pluripotency, ability to repair double strand breaks (DSBs) and commitment to apoptosis. Downregulation of CDK1 led to the loss of typical pluripotent stem cell morphology, downregulation of pluripotency markers and upregulation of a large number of differentiation markers. In addition, human pluripotent stem cells with reduced CDK1 expression accumulated a higher number of DSBs were unable to activate CHK2 expression and could not maintain G2/M arrest upon exposure to ionising radiation. CDK1 downregulation led to the accumulation of cells with abnormal numbers of mitotic organelles, multiple chromosomal abnormalities and polyploidy. Furthermore, such cells demonstrated an inability to execute apoptosis under normal culture conditions, despite a significant increase in the expression of active PARP1, resulting in tolerance and very likely further propagation of genomic instabilities and ensuing of differentiation process. On the contrary, apoptosis but not differentiation, was the preferred route for such cells when they were subjected to ionising radiation. Together these data suggest that CDK1 regulates multiple events in human pluripotent stem cells ranging from regulation of mitosis, G2/M checkpoint maintenance, execution of apoptosis, maintenance of pluripotency and genomic stability.
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Affiliation(s)
- I Neganova
- Institute of Genetic Medicine, Newcastle University, International Centre for Life, Newcastle upon Tyne NE1 3BZ, UK
| | - K Tilgner
- Institute of Genetic Medicine, Newcastle University, International Centre for Life, Newcastle upon Tyne NE1 3BZ, UK
| | - A Buskin
- Institute of Genetic Medicine, Newcastle University, International Centre for Life, Newcastle upon Tyne NE1 3BZ, UK
| | - I Paraskevopoulou
- Institute of Genetic Medicine, Newcastle University, International Centre for Life, Newcastle upon Tyne NE1 3BZ, UK
| | - S P Atkinson
- Institute of Genetic Medicine, Newcastle University, International Centre for Life, Newcastle upon Tyne NE1 3BZ, UK
| | - D Peberdy
- Institute of Genetic Medicine, Newcastle University, International Centre for Life, Newcastle upon Tyne NE1 3BZ, UK
| | - J F Passos
- Centre for Integrated Systems Biology of Ageing and Nutrition, Institute for Ageing and Health, Newcastle University, Newcastle upon Tyne NE4 5PL, UK
| | - M Lako
- Institute of Genetic Medicine, Newcastle University, International Centre for Life, Newcastle upon Tyne NE1 3BZ, UK
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Machlus KR, Italiano JE. The incredible journey: From megakaryocyte development to platelet formation. ACTA ACUST UNITED AC 2013; 201:785-96. [PMID: 23751492 PMCID: PMC3678154 DOI: 10.1083/jcb.201304054] [Citation(s) in RCA: 477] [Impact Index Per Article: 43.4] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Circulating blood platelets are specialized cells that prevent bleeding and minimize blood vessel injury. Large progenitor cells in the bone marrow called megakaryocytes (MKs) are the source of platelets. MKs release platelets through a series of fascinating cell biological events. During maturation, they become polyploid and accumulate massive amounts of protein and membrane. Then, in a cytoskeletal-driven process, they extend long branching processes, designated proplatelets, into sinusoidal blood vessels where they undergo fission to release platelets. Given the need for platelets in many pathological situations, understanding how this process occurs is an active area of research with important clinical applications.
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Affiliation(s)
- Kellie R Machlus
- Hematology Division, Department of Medicine, Brigham and Women's Hospital, Boston, MA 02115, USA
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Wang Q, Wu PC, Dong DZ, Ivanova I, Chu E, Zeliadt S, Vesselle H, Wu DY. Polyploidy road to therapy-induced cellular senescence and escape. Int J Cancer 2012; 132:1505-15. [PMID: 22945332 DOI: 10.1002/ijc.27810] [Citation(s) in RCA: 81] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2012] [Accepted: 07/31/2012] [Indexed: 12/21/2022]
Abstract
Therapy-induced cellular senescence (TCS), characterized by prolonged cell cycle arrest, is an in vivo response of human cancers to chemotherapy and radiation. Unfortunately, TCS is reversible for a subset of senescent cells, leading to cellular reproliferation and ultimately tumor progression. This invariable consequence of TCS recapitulates the clinical treatment experience of patients with advanced cancer. We report the findings of a clinicopathological study in patients with locally advanced non-small cell lung cancer demonstrating that marker of in vivo TCS following neoadjuvant therapy prognosticate adverse clinical outcome. In our efforts to elucidate key molecular pathways underlying TCS and cell cycle escape, we have previously shown that the deregulation of mitotic kinase Cdk1 and its downstream effectors are important mediators of survival and cell cycle reentry. We now report that aberrant expression of Cdk1 interferes with apoptosis and promotes the formation of polyploid senescent cells during TCS. These polyploid senescent cells represent important transition states through which escape preferentially occurs. The Cdk1 pathway is in part modulated differentially by p21 and p27 two members of the KIP cyclin-dependent kinase inhibitor family during TCS. Altogether, these studies underscore the importance of TCS in cancer therapeutics.
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Affiliation(s)
- Qin Wang
- Seattle Institute for Biomedical and Clinical Research, VA Puget Sound Health Care System, Seattle, WA 98108, USA.
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Lin YC, Sun SH, Wang FF. Suppression of Polo like kinase 1 (PLK1) by p21(Waf1) mediates the p53-dependent prevention of caspase-independent mitotic death. Cell Signal 2011; 23:1816-23. [PMID: 21726628 DOI: 10.1016/j.cellsig.2011.06.016] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2011] [Accepted: 06/20/2011] [Indexed: 01/10/2023]
Abstract
Polo-like kinase 1 (Plk1) plays key roles in many aspects of mitosis. We have previously shown that induction of p21(Waf1) by p53 is responsible for protection of cells against adriamycin-induced polyploidy formation and mitotic catastrophe. Here we show that adriamycin treatment suppressed Plk1 expression in a p53- and p21(Waf1)-dependent manner. Ablation of p21(Waf1) inhibited the adriamycin-induced p53 activation, and this inhibition was alleviated by knockdown of Plk1, suggesting that p21(Waf1)-dependent suppression of Plk1 expression is responsible for maintaining p53 activation during stress response. Plk1 associated with p53 and disrupted its interaction with target gene promoters in cells treated with adriamycin. Overexpression of Plk1 inhibited the p53-mediated prevention of caspase-independent mitotic death, but not polyploidy formation, in adriamycin-treated cells. Together our results indicate that suppression of Plk1 by p21(Waf1) is responsible for p53-dependent protection against adriamycin-induced caspase-independent mitotic death.
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Affiliation(s)
- Yi-Cheng Lin
- Institute of Biochemistry and Molecular Biology, National Yang-Ming University, Taipei, 11221, Taiwan
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Hu B, Shen KP, An HM, Wu Y, Du Q. Aqueous extract of Curcuma aromatica induces apoptosis and G2/M arrest in human colon carcinoma LS-174-T cells independent of p53. Cancer Biother Radiopharm 2011; 26:97-104. [PMID: 21348775 DOI: 10.1089/cbr.2010.0853] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
Curcuma aromatica is a common Chinese herb for treating diseases with blood stasis and has been regarded as an anticancer herb in modern clinical practice. However, the anticancer effects and related molecular mechanisms of Curcuma aromatica remain unclear. In the present study, human colon carcinoma LS-174-T cell line with wild-type p53 was used as a model cell to evaluate the anticancer effects of aqueous extract of Curcuma aromatica (AECA). AECA inhibits LS-174-T cell proliferation in a dose- and time-dependent manner and colony formation in a dose-dependent manner. AECA treatment induces apoptosis accompanied by caspase-8, -9, and -3 activation in LS-174-T cells. Moreover, blocking the activities of these caspases with a specific inhibitor significantly protected LS-174-T cells from AECA-induced apoptosis. AECA treatment also induces G2/M phase arrest in LS-174-T cells. Expression of p53 was unchanged after AECA treatment; specific silence of p53 did not influence AECA-induced apoptosis and G2/M phase arrest. Further, the expression of cyclin B1 and CDK1 was reduced by AECA. This study suggests that AECA might be effective as an antiproliferative herb for colon carcinoma, the antitumor activity of AECA may involve both extrinsic and intrinsic apoptosis, and AECA induces G2/M phase arrest via downregulation of cyclin B1 and CDK1 and without the participation of p53.
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Affiliation(s)
- Bing Hu
- The Fifth Department of Oncology and Institute of Cancer Research, Longhua Hospital, Shanghai University of Traditional Chinese Medicine, Shanghai, People's Republic of China.
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Pineault N, Cortin V, Boyer L, Garnier A, Robert A, Thérien C, Roy DC. Individual and synergistic cytokine effects controlling the expansion of cord blood CD34(+) cells and megakaryocyte progenitors in culture. Cytotherapy 2010; 13:467-80. [PMID: 21090916 DOI: 10.3109/14653249.2010.530651] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
BACKGROUND AIMS Expansion of hematopoietic progenitors ex vivo is currently investigated as a means of reducing cytopenia following stem cell transplantation. The principal objective of this study was to develop a new cytokine cocktail that would maximize the expansion of megakaryocyte (Mk) progenitors that could be used to reduce periods of thrombocytopenia. METHODS We measured the individual and synergistic effects of six cytokines [stem cell factor (SCF), FLT-3 ligand (FL), interleukin (IL)-3, IL-6, IL-9 and IL-11] commonly used to expand cord blood (CB) CD34(+) cells on the expansion of CB Mk progenitors and major myeloid populations by factorial design. RESULTS These results revealed an elaborate array of cytokine individual effects complemented by a large number of synergistic and antagonistic interaction effects. Notably, strong interactions with SCF were observed with most cytokines and its concentration level was the most influential factor for the expansion and differentiation kinetics of CB CD34(+) cells. A response surface methodology was then applied to optimize the concentrations of the selected cytokines. The newly developed cocktail composed of SCF, thrombopoietin (TPO) and FL increased the expansion of Mk progenitors and maintained efficient expansion of clonogenic progenitors and CD34(+) cells. CB cells expanded with the new cocktail were shown to provide good short- and long-term human platelet recovery and lymphomyeloid reconstitution in NOD/SCID mice. CONCLUSIONS Collectively, these results define a complex cytokine network that regulates the growth and differentiation of immature and committed hematopoietic cells in culture, and confirm that cytokine interactions have major influences on the fate of hematopoietic cells.
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Affiliation(s)
- Nicolas Pineault
- Héma-Québec, Département de Recherche et Développement, Québec City, PQ, Canada.
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Abstract
A great many cell types are necessary for the myriad capabilities of complex, multicellular organisms. One interesting aspect of this diversity of cell type is that many cells in diploid organisms are polyploid. This is called endopolyploidy and arises from cell cycles that are often characterized as "variant," but in fact are widespread throughout nature. Endopolyploidy is essential for normal development and physiology in many different organisms. Here we review how both plants and animals use variations of the cell cycle, termed collectively as endoreplication, resulting in polyploid cells that support specific aspects of development. In addition, we discuss briefly how endoreplication occurs in response to certain physiological stresses, and how it may contribute to the development of cancer. Finally, we describe the molecular mechanisms that support the onset and progression of endoreplication.
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Nakayama Y, Igarashi A, Kikuchi I, Obata Y, Fukumoto Y, Yamaguchi N. Bleomycin-induced over-replication involves sustained inhibition of mitotic entry through the ATM/ATR pathway. Exp Cell Res 2009; 315:2515-28. [PMID: 19527713 DOI: 10.1016/j.yexcr.2009.06.007] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2008] [Revised: 05/12/2009] [Accepted: 06/04/2009] [Indexed: 01/10/2023]
Abstract
Polyploid cells result in aneuploidy through aberrant chromosome segregation, possibly leading to tumorigenesis. Although polyploid cells are induced through over-replication by a variety of agents, including DNA-damaging drugs, the mechanisms that induce polyploidy have been hitherto unknown. Here, we show that treatment with bleomycin, a glycopeptide anticancer drug, induces over-replication at low cytotoxic doses. During bleomycin-induced over-replication, mitotic entry is inhibited through tyrosine phosphorylation of CDK1 along the ATM/ATR pathway in the early phase of treatment. Bleomycin-induced over-replication is inhibited by the inhibitors of the ATM/ATR pathway through abrogation of bleomycin-induced G2 arrest, and the ATM/ATR inhibitors promote cell death instead of over-replication. Following the phosphorylation of CDK1, the level of cyclin B1 is decreased in the late phase of treatment. Time-lapse imaging of clone cells that express a live cell marker of endogenous cyclin B1 revealed that cyclin B1 is degraded in G2-arrested cells upon bleomycin treatment. Our findings lead to a model of how the ATM/ATR pathway acts as a molecular switch for regulating cell fates, flipping between cell death via progress into mitosis, and over-replication via sustained G2 arrest upon DNA damage, where cyclin B1 degradation is an important factor for inducing over-replication.
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Affiliation(s)
- Yuji Nakayama
- Department of Molecular Cell Biology, Graduate School of Pharmaceutical Sciences, Chiba University, Inohana 1-8-1, Chuo-ku, Chiba, Japan.
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16
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Ullah Z, Lee CY, Depamphilis ML. Cip/Kip cyclin-dependent protein kinase inhibitors and the road to polyploidy. Cell Div 2009; 4:10. [PMID: 19490616 PMCID: PMC2697143 DOI: 10.1186/1747-1028-4-10] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2009] [Accepted: 06/02/2009] [Indexed: 02/07/2023] Open
Abstract
Cyclin-dependent kinases (CDKs) play a central role in the orderly transition from one phase of the eukaryotic mitotic cell division cycle to the next. In this context, p27Kip1 (one of the CIP/KIP family of CDK specific inhibitors in mammals) or its functional analogue in other eukarya prevents a premature transition from G1 to S-phase. Recent studies have revealed that expression of a second member of this family, p57Kip2, is induced as trophoblast stem (TS) cells differentiate into trophoblast giant (TG) cells. p57 then inhibits CDK1 activity, an enzyme essential for initiating mitosis, thereby triggering genome endoreduplication (multiple S-phases without an intervening mitosis). Expression of p21Cip1, the third member of this family, is also induced in during differentiation of TS cells into TG cells where it appears to play a role in suppressing the DNA damage response pathway. Given the fact that p21 and p57 are unique to mammals, the question arises as to whether one or both of these proteins are responsible for the induction and maintenance of polyploidy during mammalian development.
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Affiliation(s)
- Zakir Ullah
- National Institute of Child Health and Human Development, National Institutes of Health, 9000 Rockville Pike, Bethesda, MD 20892-2753, USA.
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17
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Low J, Chakravartty A, Blosser W, Dowless M, Chalfant C, Bragger P, Stancato L. Phenotypic fingerprinting of small molecule cell cycle kinase inhibitors for drug discovery. CURRENT CHEMICAL GENOMICS 2009; 3:13-21. [PMID: 20161832 PMCID: PMC2793401 DOI: 10.2174/1875397300903010013] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/21/2008] [Revised: 12/02/2008] [Accepted: 12/04/2008] [Indexed: 01/10/2023]
Abstract
Phenotypic drug discovery, primarily abandoned in the 1980’s in favor of targeted approaches to drug development, is once again demonstrating its value when used in conjunction with new technologies. Phenotypic discovery has been brought back to the fore mainly due to recent advances in the field of high content imaging (HCI). HCI elucidates cellular responses using a combination of immunofluorescent assays and computer analysis which increase both the sensitivity and throughput of phenotypic assays. Although HCI data characterize cellular responses in individual cells, these data are usually analyzed as an aggregate of the treated population and are unable to discern differentially responsive subpopulations. A collection of 44 kinase inhibitors affecting cell cycle and apoptosis were characterized with a number of univariate, bivariate, and multivariate subpopulation analyses demonstrating that each level of complexity adds additional information about the treated populations and often distinguishes between compounds with seemingly similar mechanisms of action. Finally, these subpopulation data were used to characterize compounds as they relate in chemical space.
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Affiliation(s)
- Jonathan Low
- Departments of Cancer Growth and Translational Genetics, Eli Lilly and Company, Indianapolis, IN 46265, USA
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18
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Ma D, Yu H, Lin D, Sun Y, Liu L, Liu Y, Dai B, Chen W, Cao J. S6K1 is involved in polyploidization through its phosphorylation at Thr421/Ser424. J Cell Physiol 2009; 219:31-44. [PMID: 19065636 DOI: 10.1002/jcp.21647] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Studies on polyploidization of megakaryocytes have been hampered by the lack of synchronized polyploid megakaryocytes. In this study, a relatively synchronized polyploid cell model was successfully established by employing Dami cells treated with nocodazole. In nocodazole-induced cells, cyclin B expression oscillated normally as in diploid cells and polyploid megakaryocytes. By using the nocodazole-induced Dami cell model, we found that 4E-BP1 and Thr421/Ser424 of ribosomal S6 kinase 1(S6K1) were phosphorylated mostly at M-phase in cytoplasm and oscillated in nocodazole-induced polyploid Dami cells, concomitant with increased expression of p27 and cyclin D3. However, phosphorylation of 4E-BP1 and S6K1 on Thr421/Ser424 was significantly decreased in differentiated Dami cells induced by phorbol 12-myristate 13-acetate (PMA), concomitant with increased expression of cyclin D1 and p21 and cyclin D3. Overexpression of the kinase dead form of S6K1 containing the mutation Lys 100 --> Gln in PMA-induced Dami cells increased ploidy whereas overexpression of rapamycin-resistant form of S6K1 containing the mutations Thr421 --> Glu and Ser424 --> Asp significantly dephosphorylated 4E-BP1 and reduced expression of cyclin D1, cyclin D3, p21 and p27, and slightly decreased the ploidy of PMA-induced Dami cells, compared with treatment with PMA alone. Moreover, overexpression of rapamycin-resistant form of S6K1 significantly reversed polyploidization of nocodazole-induced Dami cells. Furthermore, MAP (a novel compound synthesized recently) partly blocked the phosphorylation of S6K1 on Thr421/Ser424 and decreased the expression of p27 and polyploidization in nocodazole-induced Dami cells. Taken together, these data suggested that S6K1/4E-BP1 pathway may play an important role in polyploidization of megakaryocytes.
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Affiliation(s)
- Dongchu Ma
- Department of Experimental Medicine, Northern Hospital, Shenyang, Liaoning, China.
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19
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King WA. Chromosome variation in the embryos of domestic animals. Cytogenet Genome Res 2008; 120:81-90. [PMID: 18467828 DOI: 10.1159/000118743] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/12/2007] [Indexed: 12/30/2022] Open
Abstract
Chromosome abnormalities in the embryos of domestic animals are mostly eliminated during development. De novo chromosome abnormalities in the embryos of domestic animals have been detected in a larger proportion of embryos produced by in vitro fertilization and somatic cell nuclear transfer than in those produced by natural mating or artificial insemination. The increased incidence of abnormalities in embryos produced in vitro provides evidence for an influence of the embryo production procedures on chromosome stability. Research strategies involving cytogenetics, molecular biology and reproductive biotechnologies hold the promise of yielding insight into the mechanisms underlying chromosome instability in embryos and the impact of the in vitro environment on the chromosome make-up of embryos.
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Affiliation(s)
- W A King
- Department of Biomedical Sciences, University of Guelph, Guelph, ON, Canada.
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Itzhaki O, Skutelsky E, Kaptzan T, Siegal A, Sinai J, Schiby G, Michowitz M, Huszar M, Leibovici J. Decreased DNA ploidy may constitute a mechanism of the reduced malignant behavior of B16 melanoma in aged mice. Exp Gerontol 2008; 43:164-75. [DOI: 10.1016/j.exger.2007.12.007] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2007] [Revised: 11/03/2007] [Accepted: 11/27/2007] [Indexed: 02/08/2023]
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García P, Frampton J. The transcription factor B-Myb is essential for S-phase progression and genomic stability in diploid and polyploid megakaryocytes. J Cell Sci 2006; 119:1483-93. [PMID: 16551698 DOI: 10.1242/jcs.02870] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
The cell-cycle-regulated Myb-family transcription factor B-Myb is crucial during S phase in many diploid cell types. We have examined the expression and function of B-Myb in megakaryocytic differentiation, during which cells progress from a diploid to a polyploid state. In contrast to terminal differentiation of most haematopoietic cells, during which B-myb is rapidly downregulated, differentiation of megakaryocytes is accompanied by continued B-myb RNA and protein expression. Overexpression of B-Myb in a megakaryoblastic cell line resulted in an increase in the number of cells entering S phase and, upon induction of differentiation, the fraction of cells actively endoreplicating increased. By contrast, reduction of B-Myb levels using short interfering (si)RNA resulted in a decline in S-phase progression during both normal and endoreplicative DNA synthesis. This effect correlated with aberrant localisation of initiation of DNA replication within the nucleus and an increased fraction of cells in mitosis. Chromosomal fragmentation and other aberrations, including shorter, thicker chromatids, end-to-end fusion, and loss of a chromatid, suggest that reduced B-Myb activity is also associated with structural chromosomal instability.
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Affiliation(s)
- Paloma García
- Institute for Biomedical Research, Birmingham University Medical School, Edgbaston, Birmingham, B15 2TT, UK
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23
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King WA, Coppola G, Alexander B, Mastromonaco G, Perrault S, Nino-Soto MI, Pinton A, Joudrey EM, Betts DH. The impact of chromosomal alteration on embryo development. Theriogenology 2005; 65:166-77. [PMID: 16280155 DOI: 10.1016/j.theriogenology.2005.09.031] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Chromosome alterations, such as those affecting telomere erosion, predictably occur with each cell division, others, which involve changes to the expression and replication of the X-chromosome occur at particular stages of development, while those that involve loss or gain of chromosomes occur in a random and so far unpredictable manner. The production of embryos in vitro and by somatic cell nuclear transfer (SCNT) has been associated with altered expression of marker genes on the X-chromosome and an increased incidence of chromosomally abnormal cells during early development. In the case of SCNT embryos chromosome abnormalities may be associated with the nuclear donor cell. Telomere rebuilding subsequent to SCNT appears to vary according to species and type of donor cell used. It is speculated that the rate of telomere erosion and incidence of chromosome abnormalities affects developmental potential of early embryos and may be potential predictors of developmental outcome.
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Affiliation(s)
- W A King
- Department of Biomedical Sciences, University of Guelph, Guelph, Ont., Canada N1G 2W1.
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24
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Datta NS, Chen C, Berry JE, McCauley LK. PTHrP signaling targets cyclin D1 and induces osteoblastic cell growth arrest. J Bone Miner Res 2005; 20:1051-64. [PMID: 15883646 DOI: 10.1359/jbmr.050106] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/30/2004] [Revised: 12/11/2004] [Accepted: 01/12/2005] [Indexed: 12/23/2022]
Abstract
UNLABELLED PTHrP control of the MC3T3-E1 cell cycle machinery showed that, during differentiation, PTHrP induced G1 growth arrest. Cyclin D1 was a critical mediator as a downstream effector of cAMP, PKC, and MAPK signaling, and the process was PKA-independent. The involvement of JunB has been found critical for PTHrP effects. INTRODUCTION PTH-related protein (PTHrP) has been implicated in the control of bone cell turnover, but the mechanisms underlying its effect on osteoblast proliferation and differentiation have not been clearly defined. The mechanisms by which PTHrP impacts cell cycle proteins and the role of signaling pathways in differentiated osteoblasts were studied. MATERIALS AND METHODS To elucidate the role of PTHrP, flow cytometric analyses were performed using MC3T3-E1 and primary mouse calvarial cells. Relative protein abundance (Western blot), physical association of partners (immunoprecipitation), and kinase activities (in vitro kinase assays using either GST-Rb or H1-histone as substrates) of cell cycle-associated proteins in vehicle and PTHrP-treated 7-day differentiated cells were determined. ELISA and/or Northern blot analyses were done to evaluate JunB and cyclin D1 expression. SiRNA-mediated gene silencing experiments were performed to silence JunB protein. Finally, inhibitors of cAMP, protein kinase A (PKA), protein kinase C (PKC), and mitogen-activated protein kinase (MAPK) were used to determine involvement of different signaling pathways. RESULTS PTHrP inhibited cyclin D1 protein expression 7-fold in a dose- and time-dependent manner and increased the level of p16 protein in differentiated osteoblasts. Additionally, PTHrP reduced cyclin D1-CDK4/CDK6 and CDK1 kinase activities. Forskolin, a cAMP agonist, mimicked PTHrP action, and the PKC inhibitor, GF109203X, slightly blocked downregulation of cyclin D1, implying involvement of both cAMP and PKC. U0126, a MAPK inhibitor, alone decreased cyclin D1 protein, suggesting that the basal cyclin D1 protein is MAPK dependent. H-89, a PKA inhibitor, did not alter the effect of PTHrP on cyclin D1, suggesting a PKA-independent mechanism. Finally, expression of JunB, an activating protein-1 transcription factor, was significantly upregulated, and silencing JunB (siRNA) partially reversed the cyclin D1 response, implying involvement of JunB in the PTHrP-mediated growth arrest of MC3T3-E1 cells. CONCLUSION PTHrP upregulates JunB and reduces cyclin D1 expression while inducing G1 cell cycle arrest in differentiated osteoblasts. Such regulation could be an important determinant of the life span and bone-forming activity of osteoblasts.
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Affiliation(s)
- Nabanita S Datta
- Department of Periodontics/Prevention/Geriatrics, University of Michigan, Ann Arbor, Michigan 48109-1078, USA.
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25
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Hanada H, Takeda K, Tagami T, Nirasawa K, Akagi S, Adachi N, Takahashi S, Izaike Y, Iwamoto M, Fuchimoto DI, Miyashita N, Kubo M, Onishi A, King WA. Chromosomal instability in the cattle clones derived by somatic cell nuclear-transfer. Mol Reprod Dev 2005; 71:36-44. [PMID: 15736125 DOI: 10.1002/mrd.20283] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Cytogenetic analysis was performed on peripheral lymphocytes collected from 20 cattle clones (19 showed no overt phenotypic abnormalities except for high birth weight while 1 exhibited left forelimb contracture), the donor cell cultures from which they were derived and lymphocytes from six insemination produced control cattle. All animals and cell cultures had a modal chromosome number of 60. The frequency of abnormal cells for donor cell cultures, clones, and controls was 6.68+/-0.30%, 5.30+/-5.49%, and 5.08+/-1.04%, respectively, and did not differ significantly among the groups. There were, however, two clones derived from different donor cell cultures with high incidences of 21.29% and 20.13%, of abnormal cells consisting of pseudodiploid (near-diploid), near-triploid and near-tetraploid, and tetraploid cells. Among these two clones, one had only a few endoreduplicated nuclei although further studies are necessary to precisely define the cytological origin and nature of the abnormal cells. The clones were evaluated at multiple time points for up to 20 months of age and the incidence of abnormal lymphocytes remained stable indicating that the chromosomally abnormal nuclei found in cloned animals was not a transient event. These results show that the majority of phenotypically normal clones have normal chromosomal make up but that instability of chromosome number can occur in clones that are phenotypically normal. Therefore, cytogenetical evaluation of peripheral lymphocytes and other tissues with follow up of the phenotypical consequences of these abnormalities is warranted even in phenotypically normal clones.
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Affiliation(s)
- Hirofumi Hanada
- Department of Animal Science, Tokyo University of Agriculture, Atugi, Japan.
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26
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Fernández C, Lobo Md MDVT, Gómez-Coronado D, Lasunción MA. Cholesterol is essential for mitosis progression and its deficiency induces polyploid cell formation. Exp Cell Res 2004; 300:109-20. [PMID: 15383319 DOI: 10.1016/j.yexcr.2004.06.029] [Citation(s) in RCA: 111] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2004] [Revised: 06/24/2004] [Indexed: 12/13/2022]
Abstract
As an essential component of mammalian cell membranes, cells require cholesterol for proliferation, which is either obtained from plasma lipoproteins or synthesized intracellularly from acetyl-CoA. In addition to cholesterol, other non-sterol mevalonate derivatives are necessary for DNA synthesis, such as the phosphorylated forms of isopentane, farnesol, geranylgeraniol, and dolichol. The aim of the present study was to elucidate the role of cholesterol in mitosis. For this, human leukemia cells (HL-60) were incubated in a cholesterol-free medium and treated with SKF 104976, which inhibits cholesterol biosynthesis by blocking sterol 14alpha-demethylase, and the expression of relevant cyclins in the different phases of the cell cycle was analyzed by flow cytometry. Prolonged cholesterol starvation induced the inhibition of cytokinesis and the formation of polyploid cells, which were multinucleated and had mitotic aberrations. Supplementing the medium with cholesterol completely abolished these effects, demonstrating they were specifically due to cholesterol deficiency. This is the first evidence that cholesterol is essential for mitosis completion and that, in the absence of cholesterol, the cells fail to undergo cytokinesis, entered G1 phase at higher DNA ploidy (tetraploidy), and then progressed through S (rereplication) into G2, generating polyploid cells.
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Affiliation(s)
- Carlos Fernández
- Servicio de Bioquímica-Investigación, Hospital Ramón y Cajal, Madrid, Spain
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27
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Zhang Y, Nagata Y, Yu G, Nguyen HG, Jones MR, Toselli P, Jackson CW, Tatsuka M, Todokoro K, Ravid K. Aberrant quantity and localization of Aurora-B/AIM-1 and survivin during megakaryocyte polyploidization and the consequences of Aurora-B/AIM-1–deregulated expression. Blood 2004; 103:3717-26. [PMID: 14751927 DOI: 10.1182/blood-2003-09-3365] [Citation(s) in RCA: 57] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
AbstractMegakaryocytes skip late anaphase and cytokinesis during endomitosis. We found normal expression and localization of a fundamental regulator of mitosis, Aurora-B/AIM-1, during prophase in polyploidizing mouse bone marrow megakaryocytes. At late anaphase, however, Aurora-B/AIM-1 is absent or mislocalized. Megakaryocytes treated with a proteasome inhibitor display Aurora-B/AIM-1 properly expressed and localized to the midzone, suggesting that protein degradation contributes to this atypical appearance. In contrast, survivin, an Aurora-B/AIM-1 coregulator of mitosis, is not detected at any stage of the endomitotic cell cycle, and in most megakaryocytes proteasome inhibition does not rescue this phenotype. To further explore the importance of reduced Aurora-B/AIM-1 for polyploidization, it was overexpressed in megakaryocytes of transgenic mice. The phenotype includes increased transgenic mRNA, but not protein, in polyploidy megakaryocytes, further suggesting that Aurora-B/AIM-1 is regulated at the protein level. Aurora-B/AIM-1 protein is, however, elevated in diploid transgenic megakaryocytes. Transgenic mice also exhibit enhanced numbers of megakaryocytes with increased proliferative potential, and some mice exhibit mild decreases in ploidy level. Hence, the molecular programming involved in endomitosis is characterized by the mislocalization or absence of at least 2 critical mitotic regulators, Aurora-B/AIM-1 and survivin. Future studies will examine the impact of survivin restoration on mouse megakaryocyte polyploidization.
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Affiliation(s)
- Ying Zhang
- Department of Biochemistry, Boston University School of Medicine, 715 Albany St, K225, Boston, MA 02118.
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Hotary KB, Allen ED, Brooks PC, Datta NS, Long MW, Weiss SJ. Membrane type I matrix metalloproteinase usurps tumor growth control imposed by the three-dimensional extracellular matrix. Cell 2003; 114:33-45. [PMID: 12859896 DOI: 10.1016/s0092-8674(03)00513-0] [Citation(s) in RCA: 528] [Impact Index Per Article: 25.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Cancer cells are able to proliferate at accelerated rates within the confines of a three-dimensional (3D) extracellular matrix (ECM) that is rich in type I collagen. The mechanisms used by tumor cells to circumvent endogenous antigrowth signals have yet to be clearly defined. We find that the matrix metalloproteinase, MT1-MMP, confers tumor cells with a distinct 3D growth advantage in vitro and in vivo. The replicative advantage conferred by MT1-MMP requires pericellular proteolysis of the ECM, as proliferation is fully suppressed when tumor cells are suspended in 3D gels of protease-resistant collagen. In the absence of proteolysis, tumor cells embedded in physiologically relevant ECM matrices are trapped in a compact, spherical configuration and unable to undergo changes in cell shape or cytoskeletal reorganization required for 3D growth. These observations identify MT1-MMP as a tumor-derived growth factor that regulates proliferation by controlling cell geometry within the confines of the 3D ECM.
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Affiliation(s)
- Kevin B Hotary
- Division of Molecular Medicine and Genetics, Department of Internal Medicine, University of Michigan Comprehensive Cancer Center, University of Michigan, Ann Arbor, MI 48109, USA
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Abstract
Megakaryocytes are highly specialized precursor cells that differentiate to produce blood platelets via intermediate cytoplasmic extensions known as proplatelets. Recent advances in the understanding of megakaryocyte differentiation and platelet formation rely on a combination of genetic and cell biological studies with detailed structural analysis of cultured cells. Visualization of sequential steps in endomitosis has expanded our views on how megakaryocytes acquire polyploid DNA content, whereas studies in mouse models of platelet disorders provide clues into transcriptional pathways and those leading to the assembly of platelet-specific secretory granules. The experimental findings forge stronger links between cellular processes and molecular mechanisms, while observation of the underlying morphologic events in beginning to yield insights into the cytoskeletal mechanics of proplatelet formation. Here we review salient aspects of the emerging appreciation of the cellular and molecular basis of thrombopoiesis.
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Affiliation(s)
- J E Italiano
- Department of Medicine, Brigham & Women's Hospital and Harvard Medical School, Boston, MA, USA
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Bermejo R, Vilaboa N, Calés C. Regulation of CDC6, geminin, and CDT1 in human cells that undergo polyploidization. Mol Biol Cell 2002; 13:3989-4000. [PMID: 12429841 PMCID: PMC133609 DOI: 10.1091/mbc.e02-04-0217] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2002] [Revised: 07/23/2002] [Accepted: 08/08/2002] [Indexed: 01/10/2023] Open
Abstract
Endomitosis is the process by which mammalian megakaryocytes become polyploid during terminal differentiation. As in other endoreplicating cells, cyclin-cdk complexes are distinctly regulated, probably to overcome the strict mechanisms that prevent rereplication in most somatic cells. We have asked whether key factors involved in the assembly and licensing of replication origins are equally regulated during endomitosis. Cdc6, cdt1, and geminin expression was analyzed during differentiation of two human megakaryoblastic cell lines, HEL and K562, which respectively do and do not establish endoreplication cycles. Geminin was downregulated, whereas cdt1 levels were maintained upon differentiation of both cell lines, independently of whether cells entered extra S-phases. In contrast, cdc6 was present and remained nuclear only in differentiated endoreplicating cells. Interestingly, cdc6 protein expression was reestablished in K562 cells that underwent endomitosis after transient or stable cyclin E overexpression. The high levels of cyclin E reached in these cells appeared to influence the stabilization of cdc6 protein rather than its RNA transcription rate. Finally, cdc6 overexpression drove HEL cells into endoreplication cycles in the absence of differentiation stimuli. Our results show that both cdt1 and cdc6 are differentially regulated during megakaryocytic differentiation and suggest an active role of cdc6 in endomitosis.
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Affiliation(s)
- Rodrigo Bermejo
- Department of Biochemistry, Instituto de Investigaciones Biomédicas Alberto Sols, Universidad Autónoma de Madrid, CSIC, Arturo Duperier, 4.28029 Madrid, Spain
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Abstract
Megakaryopoiesis and subsequent thrombopoiesis occur through complex biologic steps: megakaryocyte precursors that developed from hematopoietic stem cells initially proliferate, then differentiate into mature polyploid megakaryocytes, and finally release platelets. Although a number of growth factors can augment megakaryopoiesis in vitro, thrombopoietin is a physiologic and the most potent regulator of megakaryopoiesis in vitro and in vivo. Thrombopoietin induces the growth of megakaryocyte precursors through activation of multiple signaling cascades, including Ras/mitogen-activated protein kinase (MAPK), signal transducers and activators of transcription 5 (STAT5), phosphatidylinositol 3-kinase (PI3-K)/Akt, and protein kinase C, whereas it induces megakaryocytic maturation primarily through the Ras/MAPK pathway. During the maturation step, megakaryocytes undergo polyploidization characterized by repeated rounds of DNA replication without concomitant cell division. During these rounds of replication, cytokinesis is neglected because of the down-regulated expression of AIM-1, and DNA replication occurs through the increased expression of D-type cyclins. As for transcriptional regulation during megakaryopoiesis, GATA-1 plays a central role in the lineage commitment of hematopoietic stem cells toward erythroid/megakaryocytic lineage and subsequent maturation. p45 NF-E2 is essential for platelet release from terminally differentiated megakaryocytes. At present, mutations of GATA-1, AML1, and HOXA11 genes have been found in hereditary diseases accompanying thrombocytopenia among humans.
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Affiliation(s)
- Itaru Matsumura
- Department of Hematology and Oncology, Osaka University Graduate School of Medicine, Suita, Japan
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Datta NS, Long MW. Modulation of MDM2/p53 and cyclin-activating kinase during the megakaryocyte differentiation of human erythroleukemia cells. Exp Hematol 2002; 30:158-65. [PMID: 11823051 DOI: 10.1016/s0301-472x(01)00780-9] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
OBJECTIVE This study was undertaken to address the involvement of CDK activating kinase (CAK), p53, and MDM2 proteins in the mitotic arrest associated with the acquisition of a polyploid DNA content during megakaryocyte differentiation of human erythroleukemia (HEL) cells. METHODS To evaluate this mechanism we investigated HEL cells as a model system in which there is a marked increase in DNA content during megakaryocyte differentiation induced by phorbol-diesters. Specific cell-cycle phases were separated by centrifugal elutriation and SDS PAGE and Western analysis were performed to determine the relative abundance of these proteins. Kinase assays were carried out following immunoprecipitation of cellular lysates with the antibodies to the proteins. RESULTS Polyploid HEL cells show an increase in the abundance of the CAK complex proteins, CDK7 and cyclin H, and a sixfold increase in CAK-specific activity. Increased CAK activity in polyploid HEL cells follows both the downregulation of p53 protein and its decreased association with CAK complex. Consistent with the reduction of p53, polyploid HEL cells undergo a dramatic increase in MDM2 protein abundance that in turn facilitates increased interaction of this protein with p53. CONCLUSION These observations demonstrate that deregulated expression of MDM2 and p53 during megakaryocyte differentiation allow a relaxation of the control over genomic stability, allowing further replicative rounds of DNA synthesis.
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Affiliation(s)
- Nabanita S Datta
- Department of Pediatrics and the Comprehensive Cancer Center, University of Michigan, Ann Arbor, MI, USA
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Abstract
Polyploidy, recognized by multiple copies of the haploid chromosome number, has been described in plants, insects, and in mammalian cells such as, the platelet precursors, the megakaryocytes. Several of these cell types reach high ploidy via a different cell cycle. Megakaryocytes undergo an endomitotic cell cycle, which consists of an S phase interrupted by a gap, during which the cells enter mitosis but skip anaphase B and cytokinesis. Here, we review the mechanisms that lead to this cell cycle and to polyploidy in megakaryocytes, while also comparing them to those described for other systems in which high ploidy is achieved. Overall, polyploidy is associated with an orchestrated change in expression of several genes, of which, some may be a result of high ploidy and hence a determinant of a new cell physiology, while others are inducers of polyploidization. Future studies will aim to further explore these two groups of genes.
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Affiliation(s)
- Katya Ravid
- Department of Biochemistry, Whitaker Cardiovascular Institute, Boston University School of Medicine, 715 Albany Street, Boston, MA 02118, USA.
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Ballester A, Frampton J, Vilaboa N, Calés C. Heterologous expression of the transcriptional regulator escargot inhibits megakaryocytic endomitosis. J Biol Chem 2001; 276:43413-8. [PMID: 11498537 DOI: 10.1074/jbc.m106006200] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
Certain cell types escape the strict mechanisms imposed on the majority of somatic cells to ensure the faithful inheritance of parental DNA content. This is the case in many embryonic tissues and certain adult cells such as mammalian hepatocytes and megakaryocytes. Megakaryocytic endomitosis is characterized by repeated S phases followed by abortive mitoses, resulting in mononucleated polyploid cells. Several cell cycle regulators have been proposed to play an active role in megakaryocytic polyploidization; however, little is known about upstream factors that could control endomitosis. Here we show that ectopic expression of the transcriptional repressor escargot interferes with the establishment of megakaryocytic endomitosis. Phorbol ester-induced polyploidization was inhibited in stably transfected megakaryoblastic HEL cells constitutively expressing escargot. Analysis of the expression and activity of different cell cycle factors revealed that Escargot affects the G(1)/S transition by influencing Cdk2 activity and cyclin A transcription. Nuclear proteins that specifically bind the Escargot-binding element were detected in endomitotic and non-endomitotic megakaryoblastic cells, but down-regulation occurred only during differentiation of cells that become polyploid. As Escargot was originally implicated in ploidy maintenance of Drosophila embryonic and larval cells, our results suggest that polyploidization in megakaryocytes might respond to mechanisms conserved from early development to adult cells that need to escape normal control of the diploid state.
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Affiliation(s)
- A Ballester
- Department of Biochemistry, Instituto de Investigaciones Biomédicas "Alberto Sols," Universidad Autónoma-Consejo Superior de Investigaciones Cientificas, Arturo Duperier 4, 28029 Madrid, Spain
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Carow CE, Fox NE, Kaushansky K. Kinetics of endomitosis in primary murine megakaryocytes. J Cell Physiol 2001; 188:291-303. [PMID: 11473355 DOI: 10.1002/jcp.1120] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Megakaryocytes (MKs) develop from diploid progenitor cells via successive rounds of DNA synthesis in the absence of cell division, a process termed endomitosis (EnM). While the mechanism underlying EnM is not known, studies in yeast and leukemic cell lines have suggested that it may be due to reduced levels of cyclin B1 or cdc2, leading to a decrease in mitotic kinase activity. Using flow cytometry to study EnM highly purified marrow-derived MK precursors, we found that: (1) on average, 36% of 8N-32N MKs expressed abundant cyclin B during G2/M. The percentage of cells in G2/M decreased in >64N MKs, suggesting the limit of EnM, (2) the level of cyclin B per G2/M MK increased linearly with ploidy, (3) cyclin B expression oscillated normally in polyploid MKs, (4) MPM-2, a phosphoepitope created by the action of mitotic kinases and specific to M-phase cells, was expressed in a significant fraction of polyploid MKs, and (5) there was an apparent increase of cyclin B in G1-phase in polyploid MKs. This study provides the first qualitative kinetic data regarding the cell cycle status of MKs within individual ploidy classes. It also demonstrates the feasibility of using anti-cyclin B antibody and flow cytometry to resolve G1 from G2/M populations in polyploid MKs. Finally, these findings establish that neither a relative nor absolute deficiency of mitotic kinase components is responsible for EnM, suggesting that the departure from normal cell division kinetics seen in polyploid MKs is likely due to alterations in other cell cycle regulators.
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Affiliation(s)
- C E Carow
- Department of Medicine, University of Washington, Seattle 98195-7710, USA.
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Vitrat N, Cohen-Solal K, Norol F, Guichard J, Cramer E, Vainchenker W, Wendling F, Debili N. Compared effects of Mpl ligand and other cytokines on human MK differentiation. Stem Cells 2001; 16 Suppl 2:37-51. [PMID: 11012176 DOI: 10.1002/stem.5530160707] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
The discovery of the Mpl ligand (Mpl-L), also called thrombopoietin (TPO), has facilitated in vitro investigation of human megakaryocytopoiesis. By confocal microscopy, endomitosis appeared as abortive mitosis skipping late stages of mitosis. No telophase and cytokinesis were observed. A spherical multipolar spindle which limits chromatid segregation was observed. The nuclear envelope subsequently reformed isolating all chromatids in a single nucleus. Platelet shedding was ultrastructurally studied. Platelet release occurred after formation of long cytoplasmic extensions (proplatelet formation), constriction areas delineating platelet territories. Heterogeneity in platelet size may be determined by the length of these extensions. Pegylated-recombinant human megakaryocyte growth and development factor, a truncated form of Mpl-L, was the most efficient cytokine to produce proplatelet-bearing megakaryocytes (MKs) and platelets in vitro. However, functional platelets with a normal ultrastructure could be produced in the presence of a combination of other cytokines. Finally, we investigated whether the induction of MK differentiation by the MS-5 stromal cell lines is due to Mpl-L. MS-5 cells synthesized Mpl-L transcripts and a biologically active protein. When human CD34+ cells were grown in contact or noncontact cultures with MS-5 cells, MK differentiation was observed. Soluble Mpl receptor (sMpl-Fc) addition inhibited MK growth, suggesting that the MK-promoting activity was due to Mpl-L production. Marrow stromal cell lines derived from TPO-/- mice were also able to sustain MK growth. Despite the absence of any production of Mpl-L, the sMpl-Fc continued to inhibit MK differentiation. This result suggests that the sMpl has a direct inhibitory effect and may explain the divergent results in the literature concerning the precise role of Mpl-L on the MK terminal differentiation.
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Affiliation(s)
- N Vitrat
- INSERM U362, Institut Gustave Roussy, Villejuif, France
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Kawasaki A, Matsumura I, Miyagawa JI, Ezoe S, Tanaka H, Terada Y, Tatsuka M, Machii T, Miyazaki H, Furukawa Y, Kanakura Y. Downregulation of an AIM-1 kinase couples with megakaryocytic polyploidization of human hematopoietic cells. J Cell Biol 2001; 152:275-87. [PMID: 11266445 PMCID: PMC2199624 DOI: 10.1083/jcb.152.2.275] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
During the late phase of megakaryopoiesis, megakaryocytes undergo polyploidization, which is characterized by DNA duplication without concomitant cell division. However, it remains unknown by which mechanisms this process occurs. AIM-1 and STK15 belong to the Aurora/increase-in-ploidy (Ipl)1 serine/threonine kinase family and play key roles in mitosis. In a human interleukin-3-dependent cell line, F-36P, the expressions of AIM-1 and STK15 mRNA were specifically observed at G2/M phase of the cell cycle during proliferation. In contrast, the expressions of AIM-1 and STK15 were continuously repressed during megakaryocytic polyploidization of human erythro/megakaryocytic cell lines (F-36P, K562, and CMK) treated with thrombopoietin, activated ras (H-ras(G12V)), or phorbol ester. Furthermore, their expressions were suppressed during thrombopoietin-induced polyploidization of normal human megakaryocytes. Activation of AIM-1 by the induced expression of AIM-1(wild-type) canceled TPA-induced polyploidization of K562 cells significantly, whereas that of STK15 did not. Moreover, suppression of AIM-1 by the induced expression of AIM-1 (K/R, dominant-negative type) led to polyploidization in 25% of K562 cells, whereas STK15(K/R) showed no effect. Also, the induced expression of AIM-1(K/R) in CMK cells provoked polyploidization up to 32N. These results suggested that downregulation of AIM-1 at M phase may be involved in abortive mitosis and polyploid formation of megakaryocytes.
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Affiliation(s)
- Akira Kawasaki
- Department of Hematology/Oncology, Osaka University Medical School, Osaka 565-0871, Japan
| | - Itaru Matsumura
- Department of Hematology/Oncology, Osaka University Medical School, Osaka 565-0871, Japan
| | - Jun-ichiro Miyagawa
- Department of Internal Medicine and Molecular Science, Osaka University Medical School, Osaka 565-0871, Japan
| | - Sachiko Ezoe
- Department of Hematology/Oncology, Osaka University Medical School, Osaka 565-0871, Japan
| | - Hirokazu Tanaka
- Department of Hematology/Oncology, Osaka University Medical School, Osaka 565-0871, Japan
| | - Yasuhiko Terada
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, Massachusetts 02138
| | - Masaaki Tatsuka
- Department of Regulatory Radiobiology, Research Institution for Radiation Biology and Medicine, Hiroshima University, Hiroshima 734, Japan
| | - Takashi Machii
- Department of Hematology/Oncology, Osaka University Medical School, Osaka 565-0871, Japan
| | - Hiroshi Miyazaki
- Pharmaceutical Research Laboratory, Kirin Brewery Company, Ltd., Gunma 370-1202, Japan
| | - Yusuke Furukawa
- Division of Hemopoiesis, Institute of Hematology, Jichi Medical School, Tochigi 329-04, Japan
| | - Yuzuru Kanakura
- Department of Hematology/Oncology, Osaka University Medical School, Osaka 565-0871, Japan
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Cavalloni G, Danè A, Piacibello W, Bruno S, Lamas E, Bréchot C, Aglietta M. The involvement of human-nuc gene in polyploidization of K562 cell line. Exp Hematol 2000; 28:1432-40. [PMID: 11146165 DOI: 10.1016/s0301-472x(00)00558-0] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
During megakaryocyte differentiation, the immature megakaryocyte increases its ploidy to a 2(x) DNA content by a process called endomitosis. This leads to the formation of a giant cell, the mature megakaryocyte, which gives rise to platelets. We investigated the role of human-nuc (h-nuc), a gene involved in septum formation in karyokynesis in yeast, during megakaryocytic polyploidization. Nocodazole and 12-O-tetradecanoylphorbol-13-acetate (TPA) were used to induce megakaryocytic differentiation in K562 cell line. The ploidy distribution and CD41 expression of treated K562 cells were evaluated by flow cytometry. Using quantitative reverse transcriptase polymerase chain reaction (RT-PCR), we analyzed the h-nuc mRNA expression on treated K562 cells. Mature megakaryocyte-like polyploid cells were detected at day 5-7 of treatment with nocodazole. TPA also had a similar effect on K562 cells, but it was much weaker than that of nocodazole. The analysis of ploidy of nocodazole-treated K562 cells showed that nocodazole preferentially induced polyploidization of K562 cell line with a pronounced increase of the cells 8N at day 7 of culture. Expression of CD41, a differentiation-related phenotype, was significantly induced by TPA after 7 days of treatment, showing that functional maturation was mainly induced by TPA. In contrast, there was no significant increase in CD41 expression in nocodazole-treated K562 cells, suggesting that polyploidization and functional maturation are separately regulated during megakaryocytopoiesis. RT-PCR analysis indicated that h-nuc mRNA increased after 72 hours in the presence of nocodazole, preceding the induction of polyploidization. Our data indicate that h-nuc might play a role in polyploidization during megakaryocytic differentiation via inhibition of septum formation.
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Affiliation(s)
- G Cavalloni
- Department of Biomedical Sciences and Human Oncology, Hematology/Oncology Section, University of Torino, Torino, Italy
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Genbacev O, McMaster MT, Fisher SJ. A repertoire of cell cycle regulators whose expression is coordinated with human cytotrophoblast differentiation. THE AMERICAN JOURNAL OF PATHOLOGY 2000; 157:1337-51. [PMID: 11021837 PMCID: PMC1850164 DOI: 10.1016/s0002-9440(10)64648-2] [Citation(s) in RCA: 73] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Although placental development depends on careful coordination of trophoblast proliferation and differentiation, little is known about the mitotic regulators that are key to synchronizing these events. We immunolocalized a broad range of these regulators in tissue sections of the maternal-fetal interface (first trimester through term) that contained floating villi (which include cytotrophoblasts differentiating into syncytiotrophoblasts) and anchoring villi (which include cytotrophoblasts differentiating into invasive cells). Trophoblast populations at the maternal-fetal interface stained for 16 of the cell cycle regulators whose expression we studied. The staining patterns changed as a function of both differentiation and gestational age. Differentiation along the invasive pathway was associated with entrance into, then permanent withdrawal from, the cell cycle, as evidenced by the orchestrated expression of cyclins, their catalytic subunits, and inhibitors. Surprisingly, we found coexpression of molecules that regulate different portions of the cell cycle in the syncytium. These data, which constitute one of the few examples to date of in situ localization of an extensive repertoire of mitotic regulators, provide the basis for studies aimed at understanding factors that lead to abnormal placentation.
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Affiliation(s)
- O Genbacev
- Departments of Stomatology, Obstetrics, Gynecology and Reproductive Sciences, Pharmaceutical Chemistry, and Anatomy, University of California San Francisco, San Francisco, California, USA
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40
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Eipers PG, Kale S, Taichman RS, Pipia GG, Swords NA, Mann KG, Long MW. Bone marrow accessory cells regulate human bone precursor cell development. Exp Hematol 2000; 28:815-25. [PMID: 10907643 DOI: 10.1016/s0301-472x(00)00183-1] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
OBJECTIVE Much remains to be learned about the intimate relationship between bone marrow and its surrounding tissue: the bone. We hypothesized that bone marrow accessory cell populations might regulate the development of human bone precursor cells. MATERIALS AND METHODS We used immunologic phenotyping, and isolation methods to fractionate subpopulations of nonadherent, low-density (NALD) human bone marrow cells. These cells were examined for their ability to support the serum-free survival, proliferation, and expression of bone proteins by highly purified populations of human bone precursor cells. Quantitative assessment of the accessory cell populations as well as human bone precursor cells phenotype was performed using multiparameter flow cytometry. Bone protein expression was evaluated by immunocytochemistry, Western analysis, and enzymatic analysis (for alkaline phosphatase activity). RESULTS Human bone marrow contains a cell population that stimulates the development of purified bone precursor cells. Feeder-layer studies demonstrate that these osteopoietic accessory cells (OACs) do not require cell-cell interaction to promote bone precursor cell development but, rather, produce soluble molecules responsible for their effects. Flow cytometric analyses reveal that bone marrow derived B cells, T cells, macrophages, natural killer cells, and endothelial cells do not produce this stimulatory factor. The (growth) factor cannot be replaced by addition of exogenous cytokines. The isolation of human transforming growth factor beta receptor type II (TGF-betaRII)-positive cells increases OAC-specific activity in bone cell ex vivo expansion cultures. Moreover, isolation of OAC bone marrow cells characterized by high TGF-betaRII expression, relatively low cellular complexity, and small size yields a population that is highly enriched for OACs. CONCLUSION We conclude that human bone marrow contains a population of OACs that are an obligate requirement for the early phases of bone cell development ex vivo.
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Affiliation(s)
- P G Eipers
- Department of Pediatrics, University of Michigan, Ann Arbor, USA
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41
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García P, Frampton J, Ballester A, Calés C. Ectopic expression of cyclin E allows non-endomitotic megakaryoblastic K562 cells to establish re-replication cycles. Oncogene 2000; 19:1820-33. [PMID: 10777216 DOI: 10.1038/sj.onc.1203494] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Megakaryocytes become polyploid by entering a truncated cell cycle, consisting of alternate S phases and abortive mitoses. We have investigated the regulation of the G1/S transition by comparing two megakaryoblastic cell lines, HEL and K562, which respectively do or do not become polyploid in response to phorbol esters. A pronounced downregulation of cyclin A, and to a lesser extent of cyclin E, occurred in K562 cells during the first 24 h after TPA treatment, in contrast with re-replicating HEL cells, in which both cyclins were present in individual G2/M cells. Transactivation experiments suggested that the absence of cyclin A in differentiated K562 cells could be due to a TPA-mediated inhibition of its transcription. To investigate the potential role of cyclin E in the establishment of re-replication cycles, we isolated K562 clones constitutively expressing cyclin E. The resulting clones, and also K562 cells transiently expressing cyclin E, entered re-replication cycles when treated with TPA. The transcriptional activity of the cyclin A promoter was not inhibited after TPA treatment, and although the levels of cyclin A fluctuated during further re-replication cycles, they never decreased below S phase levels. We conclude that the presence of cyclin E in megakaryoblastic G2/M cells determines cyclin A expression and allows the entrance into an extra S phase.
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Affiliation(s)
- P García
- Departamento de Bioquímica, Instituto de Investigaciones Biomédicas A. Sols, Universidad Autónoma-CSIC, Madrid, Spain
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De Rycke J, Sert V, Comayras C, Tasca C. Sequence of lethal events in HeLa cells exposed to the G2 blocking cytolethal distending toxin. Eur J Cell Biol 2000; 79:192-201. [PMID: 10777111 DOI: 10.1078/s0171-9335(04)70022-9] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
The bacterial cytolethal distending toxin (CDT) was previously shown to block the cell cycle of several cell lines at stage G2 through inactivation of the cyclin-dependent kinase Cdkl and without induction of DNA strand breaks. In the present study, we have analyzed, using various methods of analytical cytometry, the progressive transformation and delayed lethal events in the tumor-derived HeLa cell line temporarily exposed to CDT. The cell proliferation arrest induced by CDT was irreversible but, starting about two days after exposure, the G2 block released partially, concomitantly with a decline in the level of Cdkl phosphorylation. This partial release resulted in endoreduplication, leading to the emergence of a significant subpopulation of cells with a 8C DNA content, and by multipolar abortive mitosis which accounted for the mortality recorded 2 and 3 days after exposure. The other major lethal event was a micronucleation process which started to be significant about 3 days after exposure and amplified later on. Both multipolar abortive mitosis and micronucleation appeared topologically related to centrosomal amplification.
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Affiliation(s)
- J De Rycke
- UMR 960 de Microbiologie Moléculaire, Institut National de la Recherche Agronomique and Ecole Nationale Vétérinaire, Toulouse, France.
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Jones SR, Kimler BF, Justice WM, Rider V. Transit of normal rat uterine stromal cells through G1 phase of the cell cycle requires progesterone-growth factor interactions. Endocrinology 2000; 141:637-48. [PMID: 10650945 DOI: 10.1210/endo.141.2.7332] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Understanding of cell cycle regulation in hormonally responsive cells lags behind studies in other systems because few models have been available to identify the role of steroid hormones and their receptors in this process. This study investigates progesterone-dependent effects on the progression of normal uterine stromal cells through early G1 phase of the cell cycle. Quiescent rat uterine stromal cells were stimulated to reenter the cell cycle by adding serum-free medium containing medroxyprogesterone acetate (MPA) and basic fibroblast growth factor (FGF). [3H]thymidine incorporation increased significantly (P = 0.025) in cells stimulated with both FGF alone and MPA plus FGF compared with the control cells. Moreover, cells stimulated with MPA plus FGF incorporated significantly more (P = 0.01) [3H]thymidine than cells treated with FGF alone, suggesting requisite interactions between progesterone and FGF for stromal cell entry into S phase. Flow cytometric analysis of stimulated stromal cells showed FGF alone and MPA plus FGF increased significantly (P = 0.002) the percentage of cells in S phase at 12 h. Incorporation of bromodeoxyuridine into stromal cell nuclei indicated that FGF alone and MPA plus FGF increased the percentage of cells entering S phase at 18 and 24 h compared with the control cells. In addition, MPA plus FGF increased significantly (P = 0.001) the number of cells entering S phase at 24 h compared with FGF alone and sustained S phase entry compared with FGF alone, MPA alone, or the control cells. Stromal cells inhibited from G1 reentry by inhibition of mitosis showed accelerated entry into S phase in response to MPA plus FGF compared with FGF alone. Cyclin D1 messenger RNA increased in stromal cells treated with MPA plus FGF at 9, 12, and 15 h. Addition of RU 486 to cells stimulated with MPA plus FGF for 9 h reduced cyclin D1 messenger RNA accumulation by 40%. Western blot analysis of cyclin D1 immunoprecipitates indicated complex formation with both cyclin-dependent kinase 4 (Cdk4) and cyclin dependent kinase 6 (Cdk6). Cyclin D1-Cdk complexes and kinase activity correlated temporally with increased cyclin D1 expression in cells cultured with MPA plus FGF. Taken together, these results show that progesterone-FGF interactions increase cyclin D1 expression, correlating with accelerated stromal cell entry into S phase compared with cells treated with FGF alone. Moreover, progesterone plus FGF sustains the timing of stimulation for transit of uterine stromal cells through G1 into S phase compared with FGF alone.
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Affiliation(s)
- S R Jones
- Division of Molecular Biology and Biochemistry, School of Biological Sciences, University of Missouri-Kansas City, 64110, USA
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Falcieri E, Bassini A, Pierpaoli S, Luchetti F, Zamai L, Vitale M, Guidotti L, Zauli G. Ultrastructural characterization of maturation, platelet release, and senescence of human cultured megakaryocytes. THE ANATOMICAL RECORD 2000; 258:90-9. [PMID: 10603452 DOI: 10.1002/(sici)1097-0185(20000101)258:1<90::aid-ar10>3.0.co;2-g] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
The aim of this study was to evaluate the ultrastructural features of human megakaryocytes cultured in vitro. For this purpose, pluripotent CD34(+) (cluster of differentiation 34) hematopoietic progenitor cells, obtained from the peripheral blood of healthy adult donors, were differentiated along the megakaryocytic lineage in liquid cultures by the addition of the megakaryocyte-specific growth factor thrombopoietin (TPO, 100 ng/ml). After only 6-8 days, virtually all of the CD34-derived cells expressed the early megakaryocytic CD61 antigen, while, after 15-16 days, most cells also expressed the late megakaryocytic CD42a antigen. Ultrastructural analysis of cells obtained after 7 days of culture showed aspects typical of developing megakaryocytes (MK), such as formation of platelet territories and cytoplasmic fragmentation. At later (15-16 day) culture times, two distinct cell populations were observed: fully developed megakaryocytes releasing platelets into the culture medium and senescent megakaryocytes, characterized by morphological features of apoptosis. Analysis of DNA fragmentation in these cells revealed that apoptosis in megakaryocytes occurred in the absence of the internucleosomic cleavage, which is characteristic of most, but not all, types of apoptosis in cells of hematopoietic origin. On the other hand, flow cytometry of the DNA content of senescent megakaryocytes showed a subdiploid peak that was likely due to a loss of micronuclei during processing.
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Affiliation(s)
- E Falcieri
- Institute of Anatomy and Physiology, University of Urbino, 61029 Urbino, Italy.
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Zimmet J, Ravid K. Polyploidy: occurrence in nature, mechanisms, and significance for the megakaryocyte-platelet system. Exp Hematol 2000; 28:3-16. [PMID: 10658672 DOI: 10.1016/s0301-472x(99)00124-1] [Citation(s) in RCA: 143] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
OBJECTIVE Polyploidy, the state of having greater than the diploid content of DNA, has been recognized in a variety cells. Among these cell types, the megakaryocytes are classified as obligate polyploid cells, developing a polyploid DNA content regularly during the normal life cycle of the organism, while other cells may become polyploid only in response to certain stimuli. The objective of this review is to briefly describe the different cell cycle alterations that may lead to high ploidy, while focusing on the megakaryocyte and the importance of high ploidy to platelet level and function. MATERIALS AND METHODS Relevant articles appearing in scientific journals and books published in the United States and in Europe during the years 1910-1999 were used as resources for this review. We selected fundamental studies related to cell cycle regulation as well as studies relevant to the regulation of the endomitotic cell cycle in megakaryocytes. Also surveyed were publications describing the relevance of high ploidy to high platelet count and to platelet reactivity, in normal situations and in a disease state. RESULTS Different cells may achieve polyploidy through different alterations in the cell cycle machinery. CONCLUSIONS While upregulation of cyclin D3 further augments ploidy in polyploidizing megakaryocytes in vivo, future investigation should aim to explore how normal megakaryocytes may initiate the processes of skipping late anaphase and cytokinesis associated with high ploidy. In humans, under normal conditions, megakaryocyte ploidy correlates with platelet volume, and large platelets are highly reactive. This may not apply, however, to the disease state.
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Affiliation(s)
- J Zimmet
- Department of Biochemistry and Whitaker Cardiovascular Institute, Boston University School of Medicine, Mass. 02118, USA
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De Souza CP, Ye XS, Osmani SA. Checkpoint defects leading to premature mitosis also cause endoreplication of DNA in Aspergillus nidulans. Mol Biol Cell 1999; 10:3661-74. [PMID: 10564263 PMCID: PMC25657 DOI: 10.1091/mbc.10.11.3661] [Citation(s) in RCA: 46] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
The G2 DNA damage and slowing of S-phase checkpoints over mitosis function through tyrosine phosphorylation of NIMX(cdc2) in Aspergillus nidulans. We demonstrate that breaking these checkpoints leads to a defective premature mitosis followed by dramatic rereplication of genomic DNA. Two additional checkpoint functions, uvsB and uvsD, also cause the rereplication phenotype after their mutation allows premature mitosis in the presence of low concentrations of hydroxyurea. uvsB is shown to encode a rad3/ATR homologue, whereas uvsD displays homology to rad26, which has only previously been identified in Schizosaccharomyces pombe. uvsB(rad3) and uvsD(rad26) have G2 checkpoint functions over mitosis and another function essential for surviving DNA damage. The rereplication phenotype is accompanied by lack of NIME(cyclinB), but ectopic expression of active nondegradable NIME(cyclinB) does not arrest DNA rereplication. DNA rereplication can also be induced in cells that enter mitosis prematurely because of lack of tyrosine phosphorylation of NIMX(cdc2) and impaired anaphase-promoting complex function. The data demonstrate that lack of checkpoint control over mitosis can secondarily cause defects in the checkpoint system that prevents DNA rereplication in the absence of mitosis. This defines a new mechanism by which endoreplication of DNA can be triggered and maintained in eukaryotic cells.
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Affiliation(s)
- C P De Souza
- Henry Hood Research Program, Weis Center for Research, Pennsylvania State University College of Medicine, Danville, Pennsylvania 17822, USA
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Harrison LE, Wang QM, Studzinski GP. 1,25-dihydroxyvitamin D3-induced retardation of the G2/M traverse is associated with decreased levels of p34cdc2 in HL60 cells. J Cell Biochem 1999. [DOI: 10.1002/(sici)1097-4644(19991101)75:2<226::aid-jcb5>3.0.co;2-l] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
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Thrombopoietin-Induced Activation of the Mitogen-Activated Protein Kinase (MAPK) Pathway in Normal Megakaryocytes: Role in Endomitosis. Blood 1999. [DOI: 10.1182/blood.v94.4.1273] [Citation(s) in RCA: 163] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
Abstract
Thrombopoietin (TPO) plays a critical role in megakaryocyte proliferation and differentiation. Using various cultured cell lines, several recent studies have implicated the mitogen-activated protein kinase (MAPK) pathway in megakaryocyte differentiation. In the study reported here, we examined the role played by thrombopoietin-induced MAPK activity in a cytokine-dependent cell line (BAF3/Mpl) and in primary murine megakaryocytes. In both systems, extracellular signal-regulated protein kinase (ERK) 1 and 2 MAPK phosphorylation was rapidly induced by TPO stimulation. To identify the Mpl domain responsible for MAPK activation, BAF3 cells expressing truncated forms of the Mpl receptor were studied. Phosphorylation of ERKs did not require elements of the cytoplasmic signaling domain distal to Box 2 and was not dependent on phosphorylation of the adapter protein Shc. ERK activation in murine megakaryocytes was maximal at 10 minutes and was markedly decreased over the subsequent 3 hours. Next, the physiologic consequences of MAPK inhibition were studied. Using the MAPK kinase (MEK) inhibitor, PD 98059, blockade of MAPK activity substantially reduced TPO-dependent proliferation in BAF3/Mpl cells and markedly decreased mean megakaryocyte ploidy in cultures. To exclude an indirect effect of MAPK inhibition on stromal cells in whole bone marrow, CD41+ cells were selected and then cultured in TPO. The number of polyploid megakaryocytes derived from the CD41-selected cells was also significantly reduced by MEK inhibition, as was their geometric mean ploidy. These studies show an important role for MAPK in TPO-induced endomitosis and underscore the value of primary cells when studying the physiologic effects of signaling pathways.
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Thrombopoietin-Induced Activation of the Mitogen-Activated Protein Kinase (MAPK) Pathway in Normal Megakaryocytes: Role in Endomitosis. Blood 1999. [DOI: 10.1182/blood.v94.4.1273.416k04_1273_1282] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
Thrombopoietin (TPO) plays a critical role in megakaryocyte proliferation and differentiation. Using various cultured cell lines, several recent studies have implicated the mitogen-activated protein kinase (MAPK) pathway in megakaryocyte differentiation. In the study reported here, we examined the role played by thrombopoietin-induced MAPK activity in a cytokine-dependent cell line (BAF3/Mpl) and in primary murine megakaryocytes. In both systems, extracellular signal-regulated protein kinase (ERK) 1 and 2 MAPK phosphorylation was rapidly induced by TPO stimulation. To identify the Mpl domain responsible for MAPK activation, BAF3 cells expressing truncated forms of the Mpl receptor were studied. Phosphorylation of ERKs did not require elements of the cytoplasmic signaling domain distal to Box 2 and was not dependent on phosphorylation of the adapter protein Shc. ERK activation in murine megakaryocytes was maximal at 10 minutes and was markedly decreased over the subsequent 3 hours. Next, the physiologic consequences of MAPK inhibition were studied. Using the MAPK kinase (MEK) inhibitor, PD 98059, blockade of MAPK activity substantially reduced TPO-dependent proliferation in BAF3/Mpl cells and markedly decreased mean megakaryocyte ploidy in cultures. To exclude an indirect effect of MAPK inhibition on stromal cells in whole bone marrow, CD41+ cells were selected and then cultured in TPO. The number of polyploid megakaryocytes derived from the CD41-selected cells was also significantly reduced by MEK inhibition, as was their geometric mean ploidy. These studies show an important role for MAPK in TPO-induced endomitosis and underscore the value of primary cells when studying the physiologic effects of signaling pathways.
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Abstract
Development and growth of all organisms involves the faithful reproduction of cells and requires that the genome be accurately replicated and equally partitioned between two cellular progeny. In human cells, faithful segregation of the genome is accomplished by an elaborate macromolecular machine, the mitotic spindle. It is not difficult to envision how defects in components of this complex machine molecules that control its organization and function and regulators that temporally couple spindle operation to other cell cycle events could lead to chromosome missegregation. Recent evidence indicates that the persistent missegregation of chromosomes result in gains and losses of chromosomes and may be an important cause of aneuploidy. This form of chromosome instability may contribute to tumor development and progression by facilitating loss of heterozygocity (LOH) and the phenotypic expression of mutated tumor suppressor genes, and by favoring polysomy of chromosomes that harbor oncogenes. In this review, we will discuss mitotic defects that cause chromosome missegregation, examine components and regulatory mechanisms of the mitotic machine implicated in cancer, and explore mechanisms by which chromosome missegregation could lead to cancer.
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Affiliation(s)
- G A Pihan
- Department of Pathology and Program in Molecu-$blar Medicine, University of Massachusetts Medical School, 373 Plantation Street, Worcester, MA, 01605, USA
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