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  1. Article ; Online: Targeted pharmacologic inhibition of S-phase kinase-associated protein 2 (SKP2) mediated cell cycle regulation in lung and other RB-Related cancers: A brief review of current status and future prospects.

    Elahi, Abul H / Morales, Cordelia S / Xu, Xiaoliang L / Eliades, Alexia / Patsalis, Philippos C / Abramson, David H / Jhanwar, Suresh C

    Advances in biological regulation

    2023  Volume 88, Page(s) 100964

    Abstract: Small cell lung cancer (SCLC) often exhibits Rb deficiency, TRβ and p130 deletion, and SKP2 amplification, suggesting TRβ inactivation and SKP2 activation. It is reported that SKP2 targeted therapy is effective in some cancers in vitro and in vivo, but ... ...

    Abstract Small cell lung cancer (SCLC) often exhibits Rb deficiency, TRβ and p130 deletion, and SKP2 amplification, suggesting TRβ inactivation and SKP2 activation. It is reported that SKP2 targeted therapy is effective in some cancers in vitro and in vivo, but it is not reported for the treatment of SCLC and retinoblastoma. SKP2 is the synthetic lethal gene in SCLC and retinoblastoma, so SKP2 can be used for targeted therapy in SCLC and retinoblastoma. RB1 knockout mice develop several kinds of tumors, but Rb1 and SKP2 double knockout mice are healthy, suggesting that SKP2 targeted therapy may have significant effects on Rb deficient cancers with less side effects, and if successful in SCLC and retinoblastoma in vitro and in animal model, such compounds may be promising for the clinical treatment of SCLC, retinoblastoma, and variety of Rb deficient cancers. Previously our studies showed that retinoblastomas exhibit retinal cone precursor properties and depend on cone-specific thyroid hormone receptor β2 (TRβ2) and SKP2 signaling. In this study, we sought to suppress SCLC and retinoblastoma cell growth by SKP2 inhibitors as a prelude to targeted therapy in vitro and in vivo. We knocked down TRβ2 and SKP2 or over-expressed p27 in SCLC and retinoblastoma cell lines to investigate SKP2 and p27 signaling alterations. The SCLC cell lines H209 as well as retinoblastoma cell lines Y79, WERI, and RB177 were treated with SKP2 inhibitor C1 at different concentrations, following which Western blotting, Immunostaining, and cell cycle kinetics studies were performed to study SKP2 and p27 expression ubiquitination, to determine impact on cell cycle regulation and growth inhibition. TRβ2 knockdown in Y79, RB177 and H209 caused SKP2 downregulation and degradation, p27 up-regulation, and S phase arrest, whereas, SKP2 knockdown or p27 over-expression caused p27 accumulation and G1-S phase arrest. In the cell lines Y79, WERI, RB177, and H209 treatment with C1 caused SKP2 ubiquitination and degradation, p27 de-ubiquitination and accumulation, and cell growth arrest. SKP2 inhibitor C1 significantly suppressed retinoblastoma as well as SCLC cell growth by SKP2 degradation and p27 accumulation. In vivo study also showed inhibition of tumor growth with C1 treatment. Potential limitations of the success of such a therapeutic approach and its translational application in human primary tumors, and alternative approaches to overcome such limitations are briefly discussed for the treatment of retinoblastoma, SCLC and other RB-related cancers.
    MeSH term(s) Mice ; Animals ; Humans ; Retinoblastoma/drug therapy ; Retinoblastoma/genetics ; Retinoblastoma/metabolism ; S-Phase Kinase-Associated Proteins/genetics ; S-Phase Kinase-Associated Proteins/metabolism ; Retinoblastoma Protein/genetics ; Retinoblastoma Protein/metabolism ; Cell Line, Tumor ; Cell Cycle ; Mice, Knockout ; Retinal Neoplasms ; Lung/pathology
    Chemical Substances S-Phase Kinase-Associated Proteins ; Retinoblastoma Protein
    Language English
    Publishing date 2023-03-14
    Publishing country England
    Document type Review ; Journal Article ; Research Support, Non-U.S. Gov't
    ZDB-ID 2667413-0
    ISSN 2212-4934 ; 2212-4926
    ISSN (online) 2212-4934
    ISSN 2212-4926
    DOI 10.1016/j.jbior.2023.100964
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  2. Article ; Online: Effect of hyperglycaemic conditions on the response of human periodontal ligament fibroblasts to mechanical stretching.

    Papadopoulou, Adamantia / Todaro, Alexia / Eliades, Theodore / Kletsas, Dimitris

    European journal of orthodontics

    2019  Volume 41, Issue 6, Page(s) 583–590

    Abstract: Objectives: The aim of the present study was to investigate the impact of high glucose concentration on the response of human periodontal ligament fibroblasts (PDLFs) to cyclic tensile strain.: Materials and methods: Human PDLFs were incubated under ... ...

    Abstract Objectives: The aim of the present study was to investigate the impact of high glucose concentration on the response of human periodontal ligament fibroblasts (PDLFs) to cyclic tensile strain.
    Materials and methods: Human PDLFs were incubated under normal or high glucose conditions, and then were subjected to cyclic tensile stretching (8 per cent extension, 1 Hz). Gene expression was determined by quantitative real-time polymerase chain reaction. Intracellular reactive oxygen species (ROS) were determined by the 2',7'-dichlorofluorescein-diacetate assay, activation of mitogen-activated protein kinase (MAPK) was monitored by western analysis and osteoblastic differentiation was estimated with Alizarin Red-S staining.
    Results: Cyclic tensile stretching of PDLF leads to an immediate activation of extracellular signal-regulated kinase (ERK) and c-Jun N-terminal kinase (JNK), as well as to the increased expression of the transcription factor c-fos, known to regulate many osteogenesis-related genes. At later time points, the alkaline phosphatase and osteopontin genes were also upregulated. Hyperglycaemic conditions inhibited these effects. High glucose conditions were unable to increase ROS levels, but they increased the medium's osmolality. Finally, increase of osmolality mimics the inhibitory effect of hyperglycaemia on MAPK activation, c-fos and osteoblast-specific gene markers' upregulation, as well as osteogenic differentiation capacity.
    Conclusion: Our findings indicate that under high glucose conditions, human PDLFs fail to adequately respond to mechanical deformation, while their strain-elicited osteoblast differentiation ability is deteriorated. The aforementioned effects are most probably mediated by the increased osmolality under hyperglycaemic conditions.
    MeSH term(s) Alkaline Phosphatase ; Cell Differentiation ; Cells, Cultured ; Fibroblasts ; Humans ; Hyperglycemia ; Osteogenesis ; Periodontal Ligament
    Chemical Substances Alkaline Phosphatase (EC 3.1.3.1)
    Language English
    Publishing date 2019-08-21
    Publishing country England
    Document type Journal Article ; Research Support, Non-U.S. Gov't
    ZDB-ID 423731-6
    ISSN 1460-2210 ; 0141-5387
    ISSN (online) 1460-2210
    ISSN 0141-5387
    DOI 10.1093/ejo/cjz051
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  3. Article: Proof-of-Concept Pilot Study on Comprehensive Spatiotemporal Intra-Patient Heterogeneity for Colorectal Cancer With Liver Metastasis.

    Kyrochristos, Ioannis D / Glantzounis, Georgios K / Goussia, Anna / Eliades, Alexia / Achilleos, Achilleas / Tsangaras, Kyriakos / Hadjidemetriou, Irene / Elpidorou, Marilena / Ioannides, Marios / Koumbaris, George / Mitsis, Michail / Patsalis, Philippos C / Roukos, Dimitrios

    Frontiers in oncology

    2022  Volume 12, Page(s) 855463

    Abstract: Introduction: The mechanisms underlying high drug resistance and relapse rates after multi-modal treatment in patients with colorectal cancer (CRC) and liver metastasis (LM) remain poorly understood.: Objective: We evaluate the potential ... ...

    Abstract Introduction: The mechanisms underlying high drug resistance and relapse rates after multi-modal treatment in patients with colorectal cancer (CRC) and liver metastasis (LM) remain poorly understood.
    Objective: We evaluate the potential translational implications of intra-patient heterogeneity (IPH) comprising primary and matched metastatic intratumor heterogeneity (ITH) coupled with circulating tumor DNA (ctDNA) variability.
    Methods: A total of 122 multi-regional tumor and perioperative liquid biopsies from 18 patients were analyzed
    Results: The proportion of patients with ITH were 53% and 56% in primary CRC and LM respectively, while 35% of patients harbored
    Conclusion: Our proof-of-concept prospective study provides initial evidence on potential clinical superiority of IPH and warrants the conduction of precision oncology trials to evaluate the clinical utility of I PH-driven matched therapy.
    Language English
    Publishing date 2022-03-23
    Publishing country Switzerland
    Document type Journal Article
    ZDB-ID 2649216-7
    ISSN 2234-943X
    ISSN 2234-943X
    DOI 10.3389/fonc.2022.855463
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  4. Article ; Online: Proof-of-Concept Pilot Study on Comprehensive Spatiotemporal Intra-Patient Heterogeneity for Colorectal Cancer With Liver Metastasis

    Ioannis D. Kyrochristos / Georgios K. Glantzounis / Anna Goussia / Alexia Eliades / Achilleas Achilleos / Kyriakos Tsangaras / Irene Hadjidemetriou / Marilena Elpidorou / Marios Ioannides / George Koumbaris / Michail Mitsis / Philippos C. Patsalis / Dimitrios Roukos

    Frontiers in Oncology, Vol

    2022  Volume 12

    Abstract: IntroductionThe mechanisms underlying high drug resistance and relapse rates after multi-modal treatment in patients with colorectal cancer (CRC) and liver metastasis (LM) remain poorly understood.ObjectiveWe evaluate the potential translational ... ...

    Abstract IntroductionThe mechanisms underlying high drug resistance and relapse rates after multi-modal treatment in patients with colorectal cancer (CRC) and liver metastasis (LM) remain poorly understood.ObjectiveWe evaluate the potential translational implications of intra-patient heterogeneity (IPH) comprising primary and matched metastatic intratumor heterogeneity (ITH) coupled with circulating tumor DNA (ctDNA) variability.MethodsA total of 122 multi-regional tumor and perioperative liquid biopsies from 18 patients were analyzed via targeted next-generation sequencing (NGS).ResultsThe proportion of patients with ITH were 53% and 56% in primary CRC and LM respectively, while 35% of patients harbored de novo mutations in LM indicating spatiotemporal tumor evolution and the necessity of multiregional analysis. Among the 56% of patients with alterations in liquid biopsies, de novo mutations in cfDNA were identified in 25% of patients, which were undetectable in both CRC and LM. All 17 patients with driver alterations harbored mutations targetable by molecularly targeted drugs, either approved or currently under evaluation.ConclusionOur proof-of-concept prospective study provides initial evidence on potential clinical superiority of IPH and warrants the conduction of precision oncology trials to evaluate the clinical utility of I PH-driven matched therapy.
    Keywords actionable mutations ; circulating variability ; comprehensive intra-patient heterogeneity ; intratumor heterogeneity ; next-generation sequencing ; precision cancer medicine ; Neoplasms. Tumors. Oncology. Including cancer and carcinogens ; RC254-282
    Subject code 610 ; 616
    Language English
    Publishing date 2022-03-01T00:00:00Z
    Publisher Frontiers Media S.A.
    Document type Article ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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  5. Article ; Online: Investigation of Clinically Significant Molecular Aberrations in Patients with Prostate Cancer: Implications for Personalized Treatment, Prognosis and Genetic Testing.

    Fountzilas, Elena / Kouspou, Maria / Eliades, Alexia / Papadopoulou, Kyriaki / Bournakis, Evangelos / Goussia, Anna / Tsiatas, Marinos / Achilleos, Achilleas / Tsangaras, Kyriakos / Billioud, Gaetan / Loizides, Charalambos / Lemesios, Christos / Kypri, Elena / Ioannides, Marios / Koumbaris, George / Levva, Sofia / Vakalopoulos, Ioannis / Paliouras, Athanasios / Pervana, Stavroula /
    Koinis, Filippos / Bumci, Redi / Christopoulou, Athina / Meditskou, Soultana / Psyrri, Amanda / Boukovinas, Ioannis / Visvikis, Anastasios / Karavasilis, Vasilios / Koukoulis, George K / Kotsakis, Athanasios / Giannakis, Dimitrios / Fountzilas, George / Patsalis, Philippos C

    International journal of molecular sciences

    2023  Volume 24, Issue 14

    Abstract: The data on tumor molecular profiling of European patients with prostate cancer is limited. Our aim was to evaluate the prevalence and prognostic and predictive values of gene alterations in unselected patients with prostate cancer. The presence of gene ... ...

    Abstract The data on tumor molecular profiling of European patients with prostate cancer is limited. Our aim was to evaluate the prevalence and prognostic and predictive values of gene alterations in unselected patients with prostate cancer. The presence of gene alterations was assessed in patients with histologically confirmed prostate cancer using the ForeSENTIA
    MeSH term(s) Male ; Humans ; Aged ; Precision Medicine ; Prospective Studies ; Prostatic Neoplasms/diagnosis ; Prostatic Neoplasms/genetics ; Prostatic Neoplasms/therapy ; Genetic Testing
    Language English
    Publishing date 2023-07-23
    Publishing country Switzerland
    Document type Journal Article
    ZDB-ID 2019364-6
    ISSN 1422-0067 ; 1422-0067 ; 1661-6596
    ISSN (online) 1422-0067
    ISSN 1422-0067 ; 1661-6596
    DOI 10.3390/ijms241411834
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  6. Article ; Online: FOXF1 inhibits hematopoietic lineage commitment during early mesoderm specification.

    Fleury, Maud / Eliades, Alexia / Carlsson, Peter / Lacaud, Georges / Kouskoff, Valerie

    Development (Cambridge, England)

    2015  Volume 142, Issue 19, Page(s) 3307–3320

    Abstract: The molecular mechanisms orchestrating early mesoderm specification are still poorly understood. In particular, how alternate cell fate decisions are regulated in nascent mesoderm remains mostly unknown. In the present study, we investigated both in ... ...

    Abstract The molecular mechanisms orchestrating early mesoderm specification are still poorly understood. In particular, how alternate cell fate decisions are regulated in nascent mesoderm remains mostly unknown. In the present study, we investigated both in vitro in differentiating embryonic stem cells, and in vivo in gastrulating embryos, the lineage specification of early mesodermal precursors expressing or not the Forkhead transcription factor FOXF1. Our data revealed that FOXF1-expressing mesoderm is derived from FLK1(+) progenitors and that in vitro this transcription factor is expressed in smooth muscle and transiently in endothelial lineages, but not in hematopoietic cells. In gastrulating embryos, FOXF1 marks most extra-embryonic mesoderm derivatives including the chorion, the allantois, the amnion and a subset of endothelial cells. Similarly to the in vitro situation, FOXF1 expression is excluded from the blood islands and blood cells. Further analysis revealed an inverse correlation between hematopoietic potential and FOXF1 expression in vivo with increased commitment toward primitive erythropoiesis in Foxf1-deficient embryos, whereas FOXF1-enforced expression in vitro was shown to repress hematopoiesis. Altogether, our data establish that during gastrulation, FOXF1 marks all posterior primitive streak extra-embryonic mesoderm derivatives with the remarkable exception of the blood lineage. Our study further suggests that this transcription factor is implicated in actively restraining the specification of mesodermal progenitors to hematopoiesis.
    MeSH term(s) Cell Differentiation/physiology ; Cell Line ; Cell Lineage/physiology ; Flow Cytometry ; Forkhead Transcription Factors/metabolism ; Gene Expression Profiling ; Gene Transfer Techniques ; Hematopoietic Stem Cells/cytology ; Humans ; Immunohistochemistry ; Mesoderm/embryology ; Microarray Analysis ; Plasmids/genetics
    Chemical Substances FOXF1 protein, human ; Forkhead Transcription Factors
    Language English
    Publishing date 2015-08-20
    Publishing country England
    Document type Journal Article ; Research Support, Non-U.S. Gov't
    ZDB-ID 90607-4
    ISSN 1477-9129 ; 0950-1991
    ISSN (online) 1477-9129
    ISSN 0950-1991
    DOI 10.1242/dev.124685
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  7. Article ; Online: Oxidases and reactive oxygen species during hematopoiesis: a focus on megakaryocytes.

    Eliades, Alexia / Matsuura, Shinobu / Ravid, Katya

    Journal of cellular physiology

    2012  Volume 227, Issue 10, Page(s) 3355–3362

    Abstract: Reactive oxygen species (ROS), generated as a result of various reactions, control an array of cellular processes. The role of ROS during megakaryocyte (MK) development has been a subject of interest and research. The bone marrow niche is a site of MK ... ...

    Abstract Reactive oxygen species (ROS), generated as a result of various reactions, control an array of cellular processes. The role of ROS during megakaryocyte (MK) development has been a subject of interest and research. The bone marrow niche is a site of MK differentiation and maturation. In this environment, a gradient of oxygen tension, from normoxia to hypoxia results in different levels of ROS, impacting cellular physiology. This article provides an overview of major sources of ROS, their implication in different signaling pathways, and their effect on cellular physiology, with a focus on megakaryopoiesis. The importance of ROS-generating oxidases in MK biology and pathology, including myelofibrosis, is also described.
    MeSH term(s) Animals ; Hematopoiesis/physiology ; Humans ; Megakaryocytes/cytology ; Megakaryocytes/metabolism ; Oxidoreductases/metabolism ; Reactive Oxygen Species/metabolism
    Chemical Substances Reactive Oxygen Species ; Oxidoreductases (EC 1.-)
    Language English
    Publishing date 2012-02-13
    Publishing country United States
    Document type Journal Article ; Research Support, N.I.H., Extramural ; Review
    ZDB-ID 3116-1
    ISSN 1097-4652 ; 0021-9541
    ISSN (online) 1097-4652
    ISSN 0021-9541
    DOI 10.1002/jcp.24071
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  8. Article ; Online: ETV2 expression marks blood and endothelium precursors, including hemogenic endothelium, at the onset of blood development.

    Wareing, Sarah / Eliades, Alexia / Lacaud, Georges / Kouskoff, Valerie

    Developmental dynamics : an official publication of the American Association of Anatomists

    2012  Volume 241, Issue 9, Page(s) 1454–1464

    Abstract: Background: ETV2 has been identified as an important player in embryonic hematopoiesis. However, the cell populations in which this transcription factor is expressed and operates during blood specification remain to be fully characterized. Here we ... ...

    Abstract Background: ETV2 has been identified as an important player in embryonic hematopoiesis. However, the cell populations in which this transcription factor is expressed and operates during blood specification remain to be fully characterized. Here we address these issues using ES cells and a transgenic mouse line expressing green fluorescent protein (GFP) under the control of ETV2 regulatory elements, allowing us to observe the tight association between ETV2 expression and the initiation of hematopoiesis.
    Results: Both in differentiating ES cells and gastrulating embryos ETV2::GFP is mostly found co-expressed with endothelial markers and defines a subset of cells with greatly enriched primitive erythroid potential. Upon culture ETV2::GFP cells rapidly up-regulate CD41, down-regulate endothelium cell surface markers and generate definitive hematopoietic progenitors. Altogether these characteristics represent the hallmark of hemogenic endothelium cells, a specialized endothelium originating from the hemangioblast and giving rise to hematopoietic cells. Importantly, ETV2 deficiency results in a complete absence of hemogenic endothelium in differentiating ES cells and gastrulating embryos.
    Conclusions: Altogether our data reveal that ETV2 marks hemogenic endothelium in gastrulating embryos and is absolutely required for the formation of this precursor at the onset of hematopoiesis. These results enhance our understanding of embryonic hematopoiesis and the factors driving hemogenic endothelium specification.
    MeSH term(s) Animals ; Biomarkers/metabolism ; Blood/metabolism ; Embryo, Mammalian ; Endothelium, Vascular/embryology ; Endothelium, Vascular/metabolism ; Gastrulation/genetics ; Gene Expression Regulation, Developmental/physiology ; Green Fluorescent Proteins/genetics ; Green Fluorescent Proteins/metabolism ; Hemangioblasts/metabolism ; Hemangioblasts/physiology ; Hematopoiesis/genetics ; Hematopoiesis/physiology ; Hematopoietic Stem Cells/metabolism ; Hematopoietic Stem Cells/physiology ; Mice ; Mice, Transgenic ; Neovascularization, Physiologic/genetics ; Transcription Factors/genetics ; Transcription Factors/metabolism ; Transcription Factors/physiology ; Transgenes ; Validation Studies as Topic
    Chemical Substances Biomarkers ; ER71 protein, mouse ; Transcription Factors ; enhanced green fluorescent protein ; Green Fluorescent Proteins (147336-22-9)
    Language English
    Publishing date 2012-07-16
    Publishing country United States
    Document type Journal Article ; Research Support, Non-U.S. Gov't
    ZDB-ID 1102541-4
    ISSN 1097-0177 ; 1058-8388
    ISSN (online) 1097-0177
    ISSN 1058-8388
    DOI 10.1002/dvdy.23825
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  9. Article ; Online: New roles for cyclin E in megakaryocytic polyploidization.

    Eliades, Alexia / Papadantonakis, Nikolaos / Ravid, Katya

    The Journal of biological chemistry

    2010  Volume 285, Issue 24, Page(s) 18909–18917

    Abstract: Megakaryocytes are platelet precursor cells that undergo endomitosis. During this process, repeated rounds of DNA synthesis are characterized by lack of late anaphase and cytokinesis. Physiologically, the majority of the polyploid megakaryocytes in the ... ...

    Abstract Megakaryocytes are platelet precursor cells that undergo endomitosis. During this process, repeated rounds of DNA synthesis are characterized by lack of late anaphase and cytokinesis. Physiologically, the majority of the polyploid megakaryocytes in the bone marrow are cell cycle arrested. As previously reported, cyclin E is essential for megakaryocyte polyploidy; however, it has remained unclear whether up-regulated cyclin E is an inducer of polyploidy in vivo. We found that cyclin E is up-regulated upon stimulation of primary megakaryocytes by thrombopoietin. Transgenic mice in which elevated cyclin E expression is targeted to megakaryocytes display an increased ploidy profile. Examination of S phase markers, specifically proliferating cell nuclear antigen, cyclin A, and 5-bromo-2-deoxyuridine reveals that cyclin E promotes progression to S phase and cell cycling. Interestingly, analysis of Cdc6 and Mcm2 indicates that cyclin E mediates its effect by promoting the expression of components of the pre-replication complex. Furthermore, we show that up-regulated cyclin E results in the up-regulation of cyclin B1 levels, suggesting an additional mechanism of cyclin E-mediated ploidy increase. These findings define a key role for cyclin E in promoting megakaryocyte entry into S phase and hence, increase in the number of cell cycling cells and in augmenting polyploidization.
    MeSH term(s) Animals ; Blood Platelets/metabolism ; Bone Marrow/metabolism ; Cyclin B1/metabolism ; Cyclin E/chemistry ; Cyclins/metabolism ; DNA/chemistry ; Deoxyuridine/analogs & derivatives ; Deoxyuridine/metabolism ; Gene Expression Regulation ; Megakaryocytes/metabolism ; Mice ; Mice, Transgenic ; Polyploidy ; S Phase ; Thrombopoietin/metabolism
    Chemical Substances Cyclin B1 ; Cyclin E ; Cyclins ; 5-bromoethynyl-2'-deoxyuridine (80384-36-7) ; DNA (9007-49-2) ; Thrombopoietin (9014-42-0) ; Deoxyuridine (W78I7AY22C)
    Language English
    Publishing date 2010-04-14
    Publishing country United States
    Document type Journal Article ; Research Support, N.I.H., Extramural
    ZDB-ID 2997-x
    ISSN 1083-351X ; 0021-9258
    ISSN (online) 1083-351X
    ISSN 0021-9258
    DOI 10.1074/jbc.M110.102145
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  10. Article: New Roles for Cyclin E in Megakaryocytic Polyploidization

    Eliades, Alexia / Papadantonakis, Nikolaos / Ravid, Katya

    Journal of biological chemistry. 2010 June 11, v. 285, no. 24

    2010  

    Abstract: Megakaryocytes are platelet precursor cells that undergo endomitosis. During this process, repeated rounds of DNA synthesis are characterized by lack of late anaphase and cytokinesis. Physiologically, the majority of the polyploid megakaryocytes in the ... ...

    Abstract Megakaryocytes are platelet precursor cells that undergo endomitosis. During this process, repeated rounds of DNA synthesis are characterized by lack of late anaphase and cytokinesis. Physiologically, the majority of the polyploid megakaryocytes in the bone marrow are cell cycle arrested. As previously reported, cyclin E is essential for megakaryocyte polyploidy; however, it has remained unclear whether up-regulated cyclin E is an inducer of polyploidy in vivo. We found that cyclin E is up-regulated upon stimulation of primary megakaryocytes by thrombopoietin. Transgenic mice in which elevated cyclin E expression is targeted to megakaryocytes display an increased ploidy profile. Examination of S phase markers, specifically proliferating cell nuclear antigen, cyclin A, and 5-bromo-2-deoxyuridine reveals that cyclin E promotes progression to S phase and cell cycling. Interestingly, analysis of Cdc6 and Mcm2 indicates that cyclin E mediates its effect by promoting the expression of components of the pre-replication complex. Furthermore, we show that up-regulated cyclin E results in the up-regulation of cyclin B1 levels, suggesting an additional mechanism of cyclin E-mediated ploidy increase. These findings define a key role for cyclin E in promoting megakaryocyte entry into S phase and hence, increase in the number of cell cycling cells and in augmenting polyploidization.
    Language English
    Dates of publication 2010-0611
    Size p. 18909-18917.
    Publishing place American Society for Biochemistry and Molecular Biology
    Document type Article
    ZDB-ID 2997-x
    ISSN 1083-351X ; 0021-9258
    ISSN (online) 1083-351X
    ISSN 0021-9258
    Database NAL-Catalogue (AGRICOLA)

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