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Sample records for cell cycle related

  1. Cell Cycle Related Differentiation of Bone Marrow Cells into Lung Cells

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    Dooner, Mark; Aliotta, Jason M.; Pimental, Jeffrey; Dooner, Gerri J.; Abedi, Mehrdad; Colvin, Gerald; Liu, Qin; Weier, Heinz-Ulli; Dooner, Mark S.; Quesenberry, Peter J.

    2007-12-31

    Green-fluorescent protein (GFP) labeled marrow cells transplanted into lethally irradiated mice can be detected in the lungs of transplanted mice and have been shown to express lung specific proteins while lacking the expression of hematopoietic markers. We have studied marrow cells induced to transit cell cycle by exposure to IL-3, IL-6, IL-11 and steel factor at different times of culture corresponding to different phases of cell cycle. We have found that marrow cells at the G1/S interface have a 3-fold increase in cells which assume a lung phenotype and that this increase is no longer seen in late S/G2. These cells have been characterized as GFP{sup +} CD45{sup -} and GFP{sup +} cytokeratin{sup +}. Thus marrow cells with the capacity to convert into cells with a lung phenotype after transplantation show a reversible increase with cytokine induced cell cycle transit. Previous studies have shown the phenotype of bone marrow stem cells fluctuates reversibly as these cells traverse cell cycle, leading to a continuum model of stem cell regulation. The present studies indicate that marrow stem cell production of nonhematopoietic cells also fluctuates on a continuum.

  2. The neural crest cell cycle is related to phases of migration in the head

    Science.gov (United States)

    Ridenour, Dennis A.; McLennan, Rebecca; Teddy, Jessica M.; Semerad, Craig L.; Haug, Jeffrey S.; Kulesa, Paul M.

    2014-01-01

    Embryonic cells that migrate long distances must critically balance cell division in order to maintain stream dynamics and population of peripheral targets. Yet details of individual cell division events and how cell cycle is related to phases of migration remain unclear. Here, we examined these questions using the chick cranial neural crest (NC). In vivo time-lapse imaging revealed that a typical migrating NC cell division event lasted ∼1 hour and included four stereotypical steps. Cell tracking showed that dividing NC cells maintained position relative to non-dividing neighbors. NC cell division orientation and the time and distance to first division after neural tube exit were stochastic. To address how cell cycle is related to phases of migration, we used FACs analysis to identify significant spatiotemporal differences in NC cell cycle profiles. Two-photon photoconversion of single and small numbers of mKikGR-labeled NC cells confirmed that lead NC cells exhibited a nearly fourfold faster doubling time after populating the branchial arches. By contrast, Ki-67 staining showed that one out of every five later emerging NC cells exited the cell cycle after reaching proximal head targets. The relatively quiescent mitotic activity during NC cell migration to the branchial arches was altered when premigratory cells were reduced in number by tissue ablation. Together, our results provide the first comprehensive details of the pattern and dynamics of cell division events during cranial NC cell migration. PMID:24550117

  3. Aberrant expression of cell cycle and material metabolism related genes contributes to hepatocellular carcinoma occurrence.

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    Yan, Hongxian; Li, Zhaohui; Shen, Quan; Wang, Qian; Tian, Jianguo; Jiang, Qingfeng; Gao, Linbo

    2017-04-01

    This study aims to deepen our understanding of the molecular mechanism underlying the occurrence of hepatocellular carcinoma (HCC). We first downloaded a gene expression profile dataset GSE29721 (10 HCC and 10 control samples) from Gene Expression Omnibus database (http://www.ncbi.nlm.nih.gov/geo/). Differentially expressed genes (DEGs) were identified by the paired t-test using limma package. Pathway and functional enrichment analyses were performed with DAVID tools. Transcription factors were annotated with TRANSFAC database and tumor associated genes (TAGs) were annotated with TAG and TSGene databases. Protein-protein interaction (PPI) network was conducted using STRING online tool and function module was further identified with BioNet package. Totally, 527 up-regulated DEGs and 587 down-regulated DEGs were identified. GO functional and KEGG pathway enrichment analyses showed that the up-regulated DEGs were mainly related to cell division and cell cycle, while the down-regulated DEGs were largely related to material metabolism, especially secondary metabolism. Proteins encoded by DEGs CDK1, BUB1, CDC20, NCAPG, NDC80, CDCA8, MAD2L1, CCNB1, CCNA2 and BIRC5 were hub genes with high degrees in the PPI network; further module analysis detected a subnetwork consisting of 55 proteins, such as CYP2B6, ACAA1, BHMT and ALDH2. Taken together, aberrant expression of cell cycle related genes (e.g., CDK1, CCNA2, CCNB1, BUB1, MAD2L1 and CDC20) and material metabolism related genes (e.g., CYP2B6, ACAA1, BHMT and ALDH2) may contribute to HCC occurrence. Copyright © 2017 Elsevier GmbH. All rights reserved.

  4. Radiation effects on cultured mouse embryos in relation to cell division cycle

    International Nuclear Information System (INIS)

    Domon, M.

    1982-01-01

    The authors have worked with mouse embryos in vitro asking first, what are the suitable parameters to define the radiation sensitivity of embryos, and second what is a major factor determining it. The LD 50 was adopted as a parameter of the radiation sensitivity of a population in a mouse embryo system in culture. The fertilized ova were collected into Whitten's medium at various times during the pronuclear and 2-cell stages of development. They were irradiated in chambers with X-rays at doses of 0 to 800 rads. After the embryos were cultured, a set of the lethal fractions for various X-ray doses were obtained. Regarding the radiation sensitivity variation of the embryos, the LD 50 varied from 100 to 200 rads during the pronuclear stage and from 100 to 600 rads during the 2-cell stage. The embryos during the pronuclear stage were most radioresistant at early G 2 phase, followed by an increase in the sensitivity. The embryos during the 2-cell stage were also most radioresistant at early G 2 phase and were more sensitive when they got close to either the first or the second cleavage division. Furthermore, it seems that the factor 6 of the large variation was due to the extremely long G 2 period, 14 hrs for the 2-cell embryos. That is, the pooled 2-cell embryos were in a relative sense well synchronized with G 2 phase. In contrast, the synchrony was poor during the pronuclear stage, which led to less variation of the LD 50 for the pronuclear embryos. It is concluded that during the early cleavage stages of mice, radiosensitivity is mainly governed by the content of cells of various cell cycle ages in the embryo. (Namekawa, K.)

  5. Regulation of Microtubule, Apoptosis, and Cell Cycle-Related Genes by Taxotere in Prostate Cancer Cells Analyzed by Microarray

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    Yiwei Li

    2004-03-01

    Full Text Available Taxotere showed antitumor activity against solid tumors including prostate cancer. However, the molecular mechanism(s of action of Taxotere has not been fully elucidated. In order to establish such molecular mechanism(s in both hormone-insensitive (PC3 and hormone-sensitive (LNCaP prostate cancer cells, comprehensive gene expression profiles were obtained by Affymetrix Human Genome U133A Array. The RNA from the cells treated with 2 nM Taxotere was subjected to microarray analysis. We found that a total of 166, 365, and 1785 genes showed greater than twofold change in PC3 cells after 6, 36, and 72 hours of treatment, respectively compared to 57, 823, and 964 genes in LNCaP cells. The expression of tubulin was decreased, whereas the expression of microtubuleassociated proteins was increased in Taxotere-treated prostate cancer cells, confirming the microtubuletargeting effect of Taxotere. Clustering analysis showed downregulation of some genes for cell proliferation and cell cycle. In contrast, Taxotere upregulated some genes that are related to induction of apoptosis and cell cycle arrest. From these results, we conclude that Taxotere caused alterations of a large number of genes, many of which may contribute to the molecular mechanism(s by which Taxotere affects prostate cancer cells. Further molecular studies are needed in order to determine the cause and effect relationships between these genes altered by Taxotere. Nevertheless, our results could be further exploited for devising strategies to optimize therapeutic effects of Taxotere for the treatment of prostate cancer.

  6. Colorectal cancer cell-derived microvesicles are enriched in cell cycle-related mRNAs that promote proliferation of endothelial cells

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    Kim Yoon-Keun

    2009-11-01

    Full Text Available Abstract Background Various cancer cells, including those of colorectal cancer (CRC, release microvesicles (exosomes into surrounding tissues and peripheral circulation. These microvesicles can mediate communication between cells and affect various tumor-related processes in their target cells. Results We present potential roles of CRC cell-derived microvesicles in tumor progression via a global comparative microvesicular and cellular transcriptomic analysis of human SW480 CRC cells. We first identified 11,327 microvesicular mRNAs involved in tumorigenesis-related processes that reflect the physiology of donor CRC cells. We then found 241 mRNAs enriched in the microvesicles above donor cell levels, of which 27 were involved in cell cycle-related processes. Network analysis revealed that most of the cell cycle-related microvesicle-enriched mRNAs were associated with M-phase activities. The integration of two mRNA datasets showed that these M-phase-related mRNAs were differentially regulated across CRC patients, suggesting their potential roles in tumor progression. Finally, we experimentally verified the network-driven hypothesis by showing a significant increase in proliferation of endothelial cells treated with the microvesicles. Conclusion Our study demonstrates that CRC cell-derived microvesicles are enriched in cell cycle-related mRNAs that promote proliferation of endothelial cells, suggesting that microvesicles of cancer cells can be involved in tumor growth and metastasis by facilitating angiogenesis-related processes. This information will help elucidate the pathophysiological functions of tumor-derived microvesicles, and aid in the development of cancer diagnostics, including colorectal cancer.

  7. Cellular distribution of cell cycle-related molecules in the renal tubules of rats treated with renal carcinogens for 28 days: relationship between cell cycle aberration and carcinogenesis.

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    Taniai, Eriko; Hayashi, Hitomi; Yafune, Atsunori; Watanabe, Maiko; Akane, Hirotoshi; Suzuki, Kazuhiko; Mitsumori, Kunitoshi; Shibutani, Makoto

    2012-09-01

    Some renal carcinogens can induce karyomegaly, which reflects aberrant cell division in the renal tubules, from the early stages of exposure. To clarify the cell cycle-related changes during the early stages of renal carcinogenesis, we performed immunohistochemical analysis of tubular cells in male F344 rats treated with carcinogenic doses of representative renal carcinogens for 28 days. For this purpose, the karyomegaly-inducing carcinogens ochratoxin A (OTA), ferric nitrilotriacetic acid, and monuron, and the non-karyomegaly-inducing carcinogens tris(2-chloroethyl) phosphate and potassium bromate were examined. For comparison, a karyomegaly-inducing non-carcinogen, p-nitrobenzoic acid, and a non-carcinogenic non-karyomegaly-inducing renal toxicant, acetaminophen, were also examined. The outer stripe of the outer medulla (OSOM) and the cortex + OSOM were subjected to morphometric analysis of immunoreactive proximal tubular cells. Renal carcinogens, irrespective of their karyomegaly-inducing potential, increased proximal tubular cell proliferation accompanied by an increase in topoisomerase IIα-immunoreactive cells, suggesting a reflection of cell proliferation. Karyomegaly-inducing carcinogens increased nuclear Cdc2-, γH2AX-, and phosphorylated Chk2-immunoreactive cells in both areas, the former two acting in response to DNA damage and the latter one suggestive of sustained G₂. OTA, an OSOM-targeting carcinogen, could easily be distinguished from untreated controls and non-carcinogens by evaluation of molecules responding to DNA damage and G₂/M transition in the OSOM. Thus, all renal carcinogens examined facilitated proximal tubular proliferation by repeated short-term treatment. Among these, karyomegaly-inducing carcinogens may cause DNA damage and G₂ arrest in the target tubular cells.

  8. Reversible regulation of cell cycle-related genes by epigallocatechin gallate for hibernation of neonatal human tarsal fibroblasts.

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    Bae, Jung Yoon; Kanamune, Jun; Han, Dong-Wook; Matsumura, Kazuaki; Hyon, Suong-Hyu

    2009-01-01

    We investigated the hibernation effect of epigallocatechin-3-O-gallate (EGCG) on neonatal human tarsal fibroblasts (nHTFs) by analyzing the expression of cell cycle-related genes. EGCG application to culture media moderately inhibited the growth of nHTFs, and the removal of EGCG from culture media led to complete recovery of cell growth. EGCG resulted in a slight decrease in the cell population of the S and G(2)/M phases of cell cycle with concomitant increase in that of the G(0)/G(1) phase, but this cell cycle profile was restored to the initial level after EGCG removal. The expression of cyclin D1 (CCND1), CCNE2, CCN-dependent kinase 6 (CDK6), and CDK2 was restored, whereas that of CCNA, CCNB1, and CDK1 was irreversibly attenuated. The expression of a substantial number of genes analyzed by cDNA microarray was affected by EGCG application, and these affected expression levels were restored to the normal levels after EGCG removal. We also found the incorporation of FITC-EGCG into the cytosol of nHTFs and its further nuclear translocation, which might lead to the regulation of the exogenous signals directed to genes for cellular responses including proliferation and cell cycle progression. These results suggest that EGCG temporarily affects not only genes related to the cell cycle but also various other cellular functions.

  9. Influence of vitamin D on cell cycle, apoptosis, and some apoptosis related molecules in systemic lupus erythematosus

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    Nafise Tabasi

    2015-11-01

    Full Text Available Objective(s:Genetic and environmental factors are involved in the pathogenesis of systemic lupus erythematosus (SLE. Autoreactive lymphocytes are cleared through apoptosis and any disturbance in the apoptosis or clearance of apoptotic cells may disturb tolerance and lead to autoimmunity. Vitamin D has anti-proliferative effects and controls cell cycle progression. In this study we investigated the effects of vitamin D on cell cycle and apoptosis induction in lupus patients. Materials and Methods:Isolated peripheral blood mononuclear cells (PBMCs from 25 SLE patients were cultured in the presence of 50 nM of 1,25(OH2D3; then one part of the cells were stained with FITC labeled Annexin V and PI and were analyzed for apoptosis determination. For gene expression assessment of FasL, Bcl-2 and Bax, RNA was extracted from one another part of the cells, cDNA was synthesized and gene expression analysis was performed using Real time PCR. An additional part of the cells were treated with PI and the cell cycle was analyzed using flowcytometer. Results: The mean number of early apoptotic cells in vitamin D treated cells decreased significantly (18.48±7.9% compared to untreated cells (22.02±9.4% (P=0.008. Cell cycle analysis showed a significant increase in G1 phase in vitamin D treated cells (67.33±5.2% compared to non treated ones (60.77±5.7% (P =0.02. Vitamin D up-regulated the expression levels of Bcl-2 by (18.87 fold increase, and down-regulated expression of Bax (23% and FasL (25%. Conclusion:Vitamin D has regulatory effects on cell cycle progression, apoptosis and apoptosis related molecules in lupus patients.

  10. CHANGES IN ENDOGENOUS CYTOKININ CONCENTRATIONS IN CHLORELLA (CHLOROPHYCEAE) IN RELATION TO LIGHT AND THE CELL CYCLE

    Czech Academy of Sciences Publication Activity Database

    Stirk, W. A.; van Staden, J.; Novák, Ondřej; Doležal, Karel; Strnad, Miroslav; Dobrev, Petre; Sipos, G.; Oerdoeg, V.; Balint, P.

    2011-01-01

    Roč. 47, č. 2 (2011), s. 291-301 ISSN 0022-3646 R&D Projects: GA ČR GA301/08/1649; GA ČR GA206/09/1284 Institutional research plan: CEZ:AV0Z50380511 Keywords : cell cycle * Chlorella * cis-zeatin * cytokinins * N6-(2-isopentenyl)adenine Subject RIV: EF - Botanics Impact factor: 2.071, year: 2011

  11. Cell growth and division cycle

    International Nuclear Information System (INIS)

    Darzynkiewicz, Z.

    1986-01-01

    The concept of the cell cycle in its present form was introduced more than three decades ago. Studying incorporation of DNA precursors by autoradiography, these authors observed that DNA synthesis in individual cells was discontinuous and occupied a discrete portion of the cell life (S phase). Mitotic division was seen to occur after a certain period of time following DNA replication. A distinct time interval between mitosis and DNA replication was also apparent. Thus, the cell cycle was subdivided into four consecutive phases, G/sub 1/, S, G/sub 2/, and M. The G/sub 1/ and G/sub 2/ phases represented the ''gaps'' between mitosis and the start of DNA replication, and between the end of DNA replication and the onset of mitosis, respectively. The cell cycle was defined as the interval between the midpoint of mitosis and the midpoint of the subsequent mitosis of the daughter cell(s). The authors' present knowledge on the cell cycle benefited mostly from the development of four different techniques: autoradiography, time-lapse cinematography, cell synchronization and flow cytometry. Of these, autoradiography has been the most extensively used, especially during the past two decades. By providing a means to analyse incorporation of precursors of DNA, RNA or proteins by individual cells and, in combination with various techniques of cell synchronization, autoradiography yielded most of the data fundamental to the current understanding of the cell cycle-related phenomena. Kinetics of cell progression through the cell cycle could be analysed in great detail after development of such sophisticated autoradiographic approaches as measurements of the fraction of labeled mitoses (''FLM curves'') or multiple sequential cell labelling with /sup 3/H- and /sup 14/C-TdR

  12. PARP-2 regulates cell cycle-related genes through histone deacetylation and methylation independently of poly(ADP-ribosyl)ation

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    Liang, Ya-Chen; Hsu, Chiao-Yu; Yao, Ya-Li; Yang, Wen-Ming

    2013-01-01

    Highlights: ► PARP-2 acts as a transcription co-repressor independently of PARylation activity. ► PARP-2 recruits HDAC5, 7, and G9a and generates repressive chromatin. ► PARP-2 is recruited to the c-MYC promoter by DNA-binding factor YY1. ► PARP-2 represses cell cycle-related genes and alters cell cycle progression. -- Abstract: Poly(ADP-ribose) polymerase-2 (PARP-2) catalyzes poly(ADP-ribosyl)ation (PARylation) and regulates numerous nuclear processes, including transcription. Depletion of PARP-2 alters the activity of transcription factors and global gene expression. However, the molecular action of how PARP-2 controls the transcription of target promoters remains unclear. Here we report that PARP-2 possesses transcriptional repression activity independently of its enzymatic activity. PARP-2 interacts and recruits histone deacetylases HDAC5 and HDAC7, and histone methyltransferase G9a to the promoters of cell cycle-related genes, generating repressive chromatin signatures. Our findings propose a novel mechanism of PARP-2 in transcriptional regulation involving specific protein–protein interactions and highlight the importance of PARP-2 in the regulation of cell cycle progression

  13. PARP-2 regulates cell cycle-related genes through histone deacetylation and methylation independently of poly(ADP-ribosyl)ation

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    Liang, Ya-Chen; Hsu, Chiao-Yu [Institute of Molecular Biology, National Chung Hsing University, Taichung 40227, Taiwan (China); Yao, Ya-Li [Department of Biotechnology, Asia University, Taichung 41354, Taiwan (China); Yang, Wen-Ming, E-mail: yangwm@nchu.edu.tw [Institute of Molecular Biology, National Chung Hsing University, Taichung 40227, Taiwan (China)

    2013-02-01

    Highlights: ► PARP-2 acts as a transcription co-repressor independently of PARylation activity. ► PARP-2 recruits HDAC5, 7, and G9a and generates repressive chromatin. ► PARP-2 is recruited to the c-MYC promoter by DNA-binding factor YY1. ► PARP-2 represses cell cycle-related genes and alters cell cycle progression. -- Abstract: Poly(ADP-ribose) polymerase-2 (PARP-2) catalyzes poly(ADP-ribosyl)ation (PARylation) and regulates numerous nuclear processes, including transcription. Depletion of PARP-2 alters the activity of transcription factors and global gene expression. However, the molecular action of how PARP-2 controls the transcription of target promoters remains unclear. Here we report that PARP-2 possesses transcriptional repression activity independently of its enzymatic activity. PARP-2 interacts and recruits histone deacetylases HDAC5 and HDAC7, and histone methyltransferase G9a to the promoters of cell cycle-related genes, generating repressive chromatin signatures. Our findings propose a novel mechanism of PARP-2 in transcriptional regulation involving specific protein–protein interactions and highlight the importance of PARP-2 in the regulation of cell cycle progression.

  14. Overexpression of Zwint predicts poor prognosis and promotes the proliferation of hepatocellular carcinoma by regulating cell-cycle-related proteins

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    Ying H

    2018-02-01

    Full Text Available Hanning Ying,1,2 Zhiyao Xu,3 Mingming Chen,1,2 Senjun Zhou,1,2 Xiao Liang,1,2 Xiujun Cai1,2 1Department of General Surgery, 2Key Laboratory of Endoscopic Technique Research of Zhejiang Province, 3Central Lab of Biomedical Research Center, School of Medicine, Sir Run Run Shaw Hospital, Zhejiang University, Hangzhou, China Introduction: Zwint, a centromere-complex component required for the mitotic spindle checkpoint, has been reported to be overexpressed in different human cancers, but it has not been studied in human hepatocellular carcinoma (HCC.Materials and methods: The role of Zwint in hepatocellular carcinoma cell proliferation capacities was evaluated by using cell counting kit-8 (CCK8, flow cytometry, clone formation and tumor formation assay in nude mice. Western blot analysis and qPCR assay were performed to assess Zwint interacting with cell-cycle-related proteins.Results: We report that ZWINT mRNA and protein expression were upregulated in HCC samples and cell lines. An independent set of 106 HCC-tissue pairs and corresponding noncancerous tissues was evaluated for Zwint expression using immunohistochemistry, and elevated Zwint expression in HCC tissues was significantly correlated with clinicopathological features, such as tumor size and number. Kaplan–Meier survival and Cox regression analysis revealed that high expression of Zwint was correlated with poor overall survival and a greater tendency for tumor recurrence. Ectopic expression of Zwint promoted HCC-cell proliferation, and Zwint expression affected the expression of several cell-cycle proteins, including PCNA, cyclin B1, Cdc25C and CDK1.Conclusion: Our findings suggest that upregulation of Zwint may contribute to the progression of HCC and may be a prognostic biomarker and potential therapeutic target for treating HCC. Keywords: Zwint, hepatocellular carcinoma, HCC, prognosis, cell proliferation, cell cycle

  15. Regulation of cell cycle activity in the embryo of barley seeds during germination as related to grain hydration.

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    Gendreau, Emmanuel; Romaniello, Sébastien; Barad, Sophie; Leymarie, Juliette; Benech-Arnold, Roberto; Corbineau, Françoise

    2008-01-01

    Various studies indicate that cell division is a post-germination phenomenon, with radicle protrusion occurring by cell elongation, while others demonstrate that induction of the cell cycle occurs in osmo-conditioned seeds prior to radicle growth. The aim of the present work was to investigate the occurrence of the cell cycle during germination as related to grain hydration, using: (i) a flow cytometry technique to estimate the percentage of cell nuclei in G(1) and G(2) phases of the cell cycle; and (ii) reverse transcription-PCR (RT-PCR) in order to characterize the expression of the genes encoding cyclin-dependent kinases (CDKA1, CDKB1, and CDKD1) and cyclins (CYCA3, CYCB1, and CYCD4), the main genes involved in the cell cycle and its regulation. Radicle tips of embryos were isolated from seeds placed for various times on water at 30 degrees C and from grains partially hydrated at moisture contents ranging from 11% to 51% fresh weight (FW), which prevent radicle elongation. Abscisic acid (ABA) contents of the embryos during seed germination at 30 degrees C and after 48 h of partial hydration were also measured. In dry embryos, cells are mostly arrested in the G(1) phase of the cell cycle (82%), the remaining cells being in the G(2) phase, and the ABA content of the embryo was 432.7 ng g(-1) dry weight (DW). Seed imbibition was associated with a sharp decrease in ABA content as early as 5 h, while the cell cycle reactivation was a late process taking place approximately 4-6 h prior to radicle protrusion. Hydration of seeds resulted in a decrease in embryo ABA content, but it remained at a high level (207-273 ng g(-1) DW) even after 48 h at 0.41-0.51 g H2O g(-1) FW. The cell population of the radicle tips in the G(2) phase of the cell cycle, i.e. 4C nuclei, increased from 9% up to 34% at a moisture content of 51% FW. In dry seeds, CDKA1 and CDKD1 mRNAs were present at low levels, but transcripts of CDKB1, CYCA3, CYCB1, and CYCD4 were not detected. Radicle

  16. Analysis of Cell Cycle Dynamics using Probabilistic Cell Cycle Models

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    Gurkan-Cavusoglu, Evren; Schupp, Jane E.; Kinsella, Timothy J.; Loparo, Kenneth A.

    2013-01-01

    In this study, we develop asynchronous probabilistic cell cycle models to quantitatively assess the effect of ionizing radiation on a human colon cancer cell line. We use both synchronous and asynchronous cell populations and follow treated cells for up to 2 cell cycle times. The model outputs quantify the changes in cell cycle dynamics following ionizing radiation treatment, principally in the duration of both G1 and G2/M phases. PMID:22254270

  17. SCTR regulates cell cycle-related genes toward anti-proliferation in normal breast cells while having pro-proliferation activity in breast cancer cells.

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    Kang, Seongeun; Kim, Byungtak; Kang, Han-Sung; Jeong, Gookjoo; Bae, Hansol; Lee, Hyunkyung; Lee, Seungyeon; Kim, Sun Jung

    2015-11-01

    Secretin receptor (SCTR), the G-protein coupled receptor (GPCR) for secretin, has been observed to be upregulated in a few tumor types while downregulated in others, promoting or suppressing the proliferation of tumor cells, respectively. However, little is known about the molecular regulatory mechanism of dysregulation in cancer. In the present study, an analysis of the biological pathways affected by methylation in breast cancer using the methylome databases revealed that GPCRs played a major part in the affected pathway. SCTR, one of the dysregulated GPCRs, showed hypermethylation (pcells identified the G2/M stage checkpoint as the top-scored pathway. Cell cycle-related genes were all upregulated or downregulated suppressing cell proliferation. However, the overexpression of SCTR in MCF-7 cells led to a 35% increase of the cell proliferation index and 2.1-fold increase of cellular migration. Our findings indicate that SCTR suppresses the proliferation of normal breast cells, while the gene stimulates the proliferation and migration of cancer cells being downregulated by promoter methylation.

  18. An La-related protein controls cell cycle arrest by nuclear retrograde transport of tRNAs during diapause formation in Artemia.

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    Chen, Dian-Fu; Lin, Cheng; Wang, Hong-Liang; Zhang, Li; Dai, Li; Jia, Sheng-Nan; Zhou, Rong; Li, Ran; Yang, Jin-Shu; Yang, Fan; Clegg, James S; Nagasawa, Hiromichi; Yang, Wei-Jun

    2016-03-03

    In eukaryotes, tRNA trafficking between the nucleus and cytoplasm is a complex process connected with cell cycle regulation. Such trafficking is therefore of fundamental importance in cell biology, and disruption of this process has grave consequences for cell viability and survival. To cope with harsh habitats, Artemia has evolved a special reproductive mode to release encysted embryos in which cell division can be maintained in a dormancy state for a long period. Using Artemia as a peculiar model of the cell cycle, an La-related protein from Artemia, named Ar-Larp, was found to bind to tRNA and accumulate in the nucleus, leading to cell cycle arrest and controlling the onset of diapause formation in Artemia. Furthermore, exogenous gene expression of Ar-Larp could induce cell cycle arrest in cancer cells and suppress tumor growth in a xenograft mouse model, similar to the results obtained in diapause embryos of Artemia. Our study of tRNA trafficking indicated that Ar-Larp controls cell cycle arrest by binding to tRNAs and influencing their retrograde movement from the cytoplasm to the nucleus, which is connected to pathways involved in cell cycle checkpoints. These findings in Artemia offer new insights into the mechanism underlying cell cycle arrest regulation, as well as providing a potentially novel approach to study tRNA retrograde movement from the cytoplasm to the nucleus.

  19. Sequence of neuron origin and neocortical laminar fate: relation to cell cycle of origin in the developing murine cerebral wall

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    Takahashi, T.; Goto, T.; Miyama, S.; Nowakowski, R. S.; Caviness, V. S. Jr

    1999-01-01

    Neurons destined for each region of the neocortex are known to arise approximately in an "inside-to-outside" sequence from a pseudostratified ventricular epithelium (PVE). This sequence is initiated rostrolaterally and propagates caudomedially. Moreover, independently of location in the PVE, the neuronogenetic sequence in mouse is divisible into 11 cell cycles that occur over a 6 d period. Here we use a novel "birth hour" method that identifies small cohorts of neurons born during a single 2 hr period, i.e., 10-20% of a single cell cycle, which corresponds to approximately 1.5% of the 6 d neuronogenetic period. This method shows that neurons arising with the same cycle of the 11 cycle sequence in mouse have common laminar fates even if they arise from widely separated positions on the PVE (neurons of fields 1 and 40) and therefore arise at different embryonic times. Even at this high level of temporal resolution, simultaneously arising cells occupy more than one cortical layer, and there is substantial overlap in the distributions of cells arising with successive cycles. We demonstrate additionally that the laminar representation of cells arising with a given cycle is little if at all modified over the early postnatal interval of histogenetic cell death. We infer from these findings that cell cycle is a neuronogenetic counting mechanism and that this counting mechanism is integral to subsequent processes that determine cortical laminar fate.

  20. [Quercetin regulates cell cycle-related gene expression in a model of glucose-oxygen deprivation in astrocytes].

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    Yao, Fang; Zhang, Lanlan; Yuan, Zhaohu; Zeng, Yong; Wu, Bingyi

    2013-09-01

    To study the effect of quercetin on gene expression in astrocytes after glucose-oxygen deprivation and the underlying mechanism. The primary cultured astrocytes were randomly divided into glucose-oxygen deprivation group (only treated with glucose-oxygen deprivation for 4 hours) and glucose-oxygen deprivation combined with quercetin-treated group (glucose-oxygen deprivation for 4 hours combined with quercetin treatment for 24 hours). Their mRNA expressions were analyzed by the large-scale oligo microarray. The differential genes obtained were further confirmed by real-time quantitative PCR (qRT-PCR). Compared with the glucose-oxygen deprivation group, the glucose-oxygen deprivation combined with quercetin-treated group presented the changes in the expressions of 31 genes that were related to cell cycle, of which 5 genes were up-regulated and 26 were down-regulated. Six of those differential genes were confirmed by qRT-PCR and the result of their differential expressions was consistent with that by large-scale oligo microarray. Quercetin can regulate some of cell cycle-related genes in astrocytes after glucose-oxygen deprivation.

  1. The Addiction-Related Protein ANKK1 is Differentially Expressed During the Cell Cycle in Neural Precursors.

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    España-Serrano, Laura; Guerra Martín-Palanco, Noelia; Montero-Pedrazuela, Ana; Pérez-Santamarina, Estela; Vidal, Rebeca; García-Consuegra, Inés; Valdizán, Elsa María; Pazos, Angel; Palomo, Tomás; Jiménez-Arriero, Miguel Ángel; Guadaño-Ferraz, Ana; Hoenicka, Janet

    2017-05-01

    TaqIA is a polymorphism associated with addictions and dopamine-related traits. It is located in the ankyrin repeat and kinase domain containing 1 gene (ANKK1) nearby the gene for the dopamine D2 receptor (D2R). Since ANKK1 function is unknown, TaqIA-associated traits have been explained only by differences in D2R. Here we report ANKK1 studies in mouse and human brain using quantitative real-time PCR, Western blot, immunohistochemistry, and flow cytometry. ANKK1 mRNA and protein isoforms vary along neurodevelopment in the human and mouse brain. In mouse adult brain ANKK1 is located in astrocytes, nuclei of postmitotic neurons and neural precursors from neurogenic niches. In both embryos and adults, nuclei of neural precursors show significant variation of ANKK1 intensity. We demonstrate a correlation between ANKK1 and the cell cycle. Cell synchronization experiments showed a significant increment of ANKK1-kinase in mitotic cells while ANKK1-kinase overexpression affects G1 and M phase that were found to be modulated by ANKK1 alleles and apomorphine treatment. Furthermore, during embryonic neurogenesis ANKK1 was expressed in slow-dividing neuroblasts and rapidly dividing precursors which are mitotic cells. These results suggest a role of ANKK1 during the cell cycle in neural precursors thus providing biological support to brain structure involvement in the TaqIA-associated phenotypes. © The Author 2016. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

  2. γ-Carboxymuconolactone decarboxylase: a novel cell cycle-related basal body protein in the early branching eukaryote Trichomonas vaginalis.

    Science.gov (United States)

    Cheng, Wei-Hung; Huang, Kuo-Yang; Huang, Po-Jung; Lee, Chi-Ching; Yeh, Yuan-Ming; Ku, Fu-Man; Lin, Rose; Cheng, Mei-Ling; Chiu, Cheng-Hsun; Tang, Petrus

    2017-09-26

    γ-Carboxymuconolactone decarboxylase (CMD) participates in the β-ketoadipate pathway, which catalyzes aromatic compounds to produce acetyl- or succinyl-CoA, in prokaryotes and yeast. Our previous study demonstrated that expression of a CMD homologue that contains two signatures (dualCMD) is negatively regulated by iron in Trichomonas vaginalis. However, we were not able to identify the components of the β-ketoadipate pathway in the parasite's genome. These observations prompted us to investigate the biological functions of this novel CMD homologue in T. vaginalis. The specific anti-TvCMD1 antibody was generated, and the expression of TvCMD1 in T. vaginalis cultured under iron-rich and iron-deficient were evaluated. Phylogenetic, metabolomic and substrate induction (protocatechuate and benzoate) analysis were conducted to clarify the function of dualCMD in trichomonad cells. Subcellular localization of TvCMD1 was observed by confocal microscopy. The cell cycle-related role of TvCMD1 was assessed by treating cells with G2/M inhibitor nocodazole. We confirmed that T. vaginalis is not able to catabolize the aromatic compounds benzoate and protocatechuate, which are known substrates of the β-ketoadipate pathway. Using immunofluorescence microscopy, we found that TvCMD1 is spatially associated with the basal body, a part of the cytoskeletal organizing center in T. vaginalis. TvCMD1 accumulated upon treatment with the G2/M inhibitor nocodazole. Additionally, TvCMD1 was expressed and transported to/from the basal body during cytokinesis, suggesting that TvCMD1 plays a role in cell division. We demonstrated that TvCMD1 is unlikely to participate in the β-ketoadipate pathway and demonstrated that it is a novel basal body-localizing (associated) protein. This model sheds light on the importance of genes that are acquired laterally in the coevolution of ancient protists, which surprisingly functions in cell cycle regulation of T. vaginalis.

  3. Apoptosis by antitumor agents and other factors in relation to cell cycle checkpoints

    International Nuclear Information System (INIS)

    Kondo, Sohei

    1995-01-01

    More than a cancer patients died in 1993 after treatment with antineoplastic derivatives of 5-fluorouracil and the antiherpes drug Sorivudine. This paper gives a short review of previous reports showing that killing of cells by 5-fluorouracil and other antitumor agents, including radiation at high doses, results from activation of apoptosis in the G2 phase. On the other hand, apoptosis of lymphocytes by radiation at low doses and treatment with other agents is known to occur in the G1 phase. The cells dying in the G1 or G2 phase could share the same final self-killing steps. For these common steps, I assume a mitotic catastrophe model, in which commitment to self-killing results from premature activation of the mitosis machinery, and propose a concept of a 'G1/G2 death circuit' for cells dying in the G1/G2 phase by short circuit to the M phase. Based on this model, reported modes of cell death, spontaneously occurring or after treatment with various agents, are classified by the phase of dying cells. The associations of incomplete apoptosis with production of chromosomal aberrations and prevention of tumorigenesis by complete apoptosis of carcinogen-treated cells are discussed. A presumptive rule for differentiation of G1 apoptosis and G2 apoptosis is proposed. (author)

  4. OSBP-related protein 8 (ORP8) interacts with Homo sapiens sperm associated antigen 5 (SPAG5) and mediates oxysterol interference of HepG2 cell cycle

    Energy Technology Data Exchange (ETDEWEB)

    Zhong, Wenbin [Department of Biotechnology, Jinan University, Guangzhou 510632 (China); Zhou, You [Minerva Foundation Institute for Medical Research, Helsinki (Finland); Li, Jiwei [Department of Biotechnology, Jinan University, Guangzhou 510632 (China); Mysore, Raghavendra [Minerva Foundation Institute for Medical Research, Helsinki (Finland); Luo, Wei; Li, Shiqian [Department of Biotechnology, Jinan University, Guangzhou 510632 (China); Chang, Mau-Sun [Institute of Biochemical Sciences, National Taiwan University, No. 1, Taipei, Taiwan (China); Olkkonen, Vesa M. [Minerva Foundation Institute for Medical Research, Helsinki (Finland); Yan, Daoguang, E-mail: tydg@jnu.edu.cn [Department of Biotechnology, Jinan University, Guangzhou 510632 (China)

    2014-04-01

    We earlier identified OSBP-related protein 8 (ORP8) as an endoplasmic reticulum/nuclear envelope oxysterol-binding protein implicated in cellular lipid homeostasis, migration, and organization of the microtubule cytoskeleton. Here, a yeast two-hybrid screen identified Homo sapiens sperm associated antigen 5 (SPAG5)/Astrin as interaction partner of ORP8. The putative interaction was further confirmed by pull-down and co-immunoprecipitation assays. ORP8 did not colocalize with kinetochore-associated SPAG5 in mitotic HepG2 or HuH7 cells, but overexpressed ORP8 was capable of recruiting SPAG5 onto endoplasmic reticulum membranes in interphase cells. In our experiments, 25-hydroxycholesterol (25OHC) retarded the HepG2 cell cycle, causing accumulation in G2/M phase; ORP8 overexpression resulted in the same phenotype. Importantly, ORP8 knock-down dramatically inhibited the oxysterol effect on HepG2 cell cycle, suggesting a mediating role of ORP8. Furthermore, knock-down of SPAG5 significantly reduced the effects of both ORP8 overexpression and 25OHC on the cell cycle, placing SPAG5 downstream of the two cell-cycle interfering factors. Taken together, the present results suggest that ORP8 may via SPAG5 mediate oxysterol interference of the HepG2 cell cycle. - Highlights: • The oxysterol-binding protein ORP8 was found to interact with the mitotic regulator SPAG5/Astrin. • Treatment of HepG2 cells with 25-hydroxycholesterol caused cell cycle retardation in G2/M. • ORP8 overexpression caused a similar G2/M accumulation, and ORP8 knock-down reversed the 25-hydroxycholesterol effect. • Reduction of cellular of SPAG5/Astrin reversed the cell cycle effects of both 25-hydroxycholesterol and ORP8 overexpression. • Our results suggest that ORP8 mediates via SPAG5/Astrin the oxysterol interference of HepG2 cell cycle.

  5. OSBP-related protein 8 (ORP8) interacts with Homo sapiens sperm associated antigen 5 (SPAG5) and mediates oxysterol interference of HepG2 cell cycle

    International Nuclear Information System (INIS)

    Zhong, Wenbin; Zhou, You; Li, Jiwei; Mysore, Raghavendra; Luo, Wei; Li, Shiqian; Chang, Mau-Sun; Olkkonen, Vesa M.; Yan, Daoguang

    2014-01-01

    We earlier identified OSBP-related protein 8 (ORP8) as an endoplasmic reticulum/nuclear envelope oxysterol-binding protein implicated in cellular lipid homeostasis, migration, and organization of the microtubule cytoskeleton. Here, a yeast two-hybrid screen identified Homo sapiens sperm associated antigen 5 (SPAG5)/Astrin as interaction partner of ORP8. The putative interaction was further confirmed by pull-down and co-immunoprecipitation assays. ORP8 did not colocalize with kinetochore-associated SPAG5 in mitotic HepG2 or HuH7 cells, but overexpressed ORP8 was capable of recruiting SPAG5 onto endoplasmic reticulum membranes in interphase cells. In our experiments, 25-hydroxycholesterol (25OHC) retarded the HepG2 cell cycle, causing accumulation in G2/M phase; ORP8 overexpression resulted in the same phenotype. Importantly, ORP8 knock-down dramatically inhibited the oxysterol effect on HepG2 cell cycle, suggesting a mediating role of ORP8. Furthermore, knock-down of SPAG5 significantly reduced the effects of both ORP8 overexpression and 25OHC on the cell cycle, placing SPAG5 downstream of the two cell-cycle interfering factors. Taken together, the present results suggest that ORP8 may via SPAG5 mediate oxysterol interference of the HepG2 cell cycle. - Highlights: • The oxysterol-binding protein ORP8 was found to interact with the mitotic regulator SPAG5/Astrin. • Treatment of HepG2 cells with 25-hydroxycholesterol caused cell cycle retardation in G2/M. • ORP8 overexpression caused a similar G2/M accumulation, and ORP8 knock-down reversed the 25-hydroxycholesterol effect. • Reduction of cellular of SPAG5/Astrin reversed the cell cycle effects of both 25-hydroxycholesterol and ORP8 overexpression. • Our results suggest that ORP8 mediates via SPAG5/Astrin the oxysterol interference of HepG2 cell cycle

  6. Peroxisome proliferator-activated receptors (PPAR) agonists affect cell viability, apoptosis and expression of cell cycle related proteins in cell lines of glial brain tumors

    Czech Academy of Sciences Publication Activity Database

    Straková, N.; Ehrmann, J.; Bartoš, Jan; Malíková, J.; Doležel, Jaroslav; Kolář, Z.

    2005-01-01

    Roč. 52, - (2005), s. 126-136 ISSN 0028-2685 Institutional research plan: CEZ:AV0Z50380511; CEZ:AV0Z5038910 Keywords : PPAR * glioplasma * cell cycle Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 0.731, year: 2005

  7. Expression patterns of cell cycle components in sporadic and neurofibromatosis type 1-related malignant peripheral nerve sheath tumors

    NARCIS (Netherlands)

    Agesen, Trude Holmeide; Florenes, Viva Ann; Molenaar, Willemina M.; Lind, Guro E.; Berner, Jeane-Marie; Plaat, Boudewijn E.C.; Komdeur, Rudy; Myklebost, Ola; van den Berg, Eva; Lothe, Ragnhild A.

    The molecular biology underlying the development of highly malignant peripheral nerve sheath tumors (MPNSTs) remains mostly unknown. In the present study, the expression pattern of 10 selected cell cycle components is investigated in a series of 15 MPNSTs from patients with (n = 9) or without (n =

  8. Protein tyrosine nitration in the cell cycle

    International Nuclear Information System (INIS)

    Jia, Min; Mateoiu, Claudia; Souchelnytskyi, Serhiy

    2011-01-01

    Highlights: → Enrichment of 3-nitrotyrosine containing proteins from cells synchronized in different phases of the cell cycle. → Identification of 76 tyrosine nitrated proteins that change expression during the cell cycle. → Nineteen identified proteins were previously described as regulators of cell proliferation. -- Abstract: Nitration of tyrosine residues in proteins is associated with cell response to oxidative/nitrosative stress. Tyrosine nitration is relatively low abundant post-translational modification that may affect protein functions. Little is known about the extent of protein tyrosine nitration in cells during progression through the cell cycle. Here we report identification of proteins enriched for tyrosine nitration in cells synchronized in G0/G1, S or G2/M phases of the cell cycle. We identified 27 proteins in cells synchronized in G0/G1 phase, 37 proteins in S phase synchronized cells, and 12 proteins related to G2/M phase. Nineteen of the identified proteins were previously described as regulators of cell proliferation. Thus, our data indicate which tyrosine nitrated proteins may affect regulation of the cell cycle.

  9. Light-dark (12:12) cycle of carbon and nitrogen metabolism in Crocosphaera watsonii WH8501: relation to the cell cycle.

    Science.gov (United States)

    Dron, Anthony; Rabouille, Sophie; Claquin, Pascal; Le Roy, Bertrand; Talec, Amélie; Sciandra, Antoine

    2012-04-01

    This study provides with original data sets on the physiology of the unicellular diazotrophic cyanobacterium Crocosphaera watsonii WH8501, maintained in continuous culture in conditions of obligate diazotrophy. Cultures were exposed to a 12:12 light-dark regime, representative of what they experience in nature and where growth is expected to be balanced. Nitrogen and carbon metabolism were monitored at high frequency and their dynamics was compared with the cell cycle. Results reveal a daily cycle in the physiological and biochemical parameters, tightly constrained by the timely decoupled processes of N(2) fixation and carbon acquisition. The cell division rate increased concomitantly to carbon accumulation and peaked 6 h into the light. The carbon content reached a maximum at the end of the light phase. N(2) fixation occurred mostly during the dark period and peaked between 9 and 10 h into the night, while DNA synthesis, reflected by DNA fluorescence, increased until the end of the night. Consequently, cells in G1- and S-phases present a marked decrease in their C:N ratio. Nitrogen acquisition through N(2) fixation exceeded 1.3- to 3-fold the nitrogen requirements for growth, suggesting that important amounts of nitrogen are excreted even under conditions supposed to favour balanced, carbon and nitrogen acquisitions. © 2011 Society for Applied Microbiology and Blackwell Publishing Ltd.

  10. Roles of Rad51 protein in homologous recombination in mammalian cells: relation with repair, replication and cell cycle

    International Nuclear Information System (INIS)

    Lambert, S.

    2001-01-01

    Homologous recombination (HR) is a fundamental process, allowing a faithful repair. In mammalian, MmRAD51, which is the homologue of Saccharomyces cerevisiae ScRAD51 key protein for HR, is an essential gene. This work is based on the characterisation of viable hyper and hypo-recombinant cell lines specifically affected in the Rad51 pathway. By expressing wild type and dominant negative forms of MmRad51, we demonstrated that Rad51 pathway participates to the repair by HR to induced DNA damages. However, inhibition of the Rad 51 pathway does not affect cell viability, spontaneously or after irradiation, whereas, radiation induced HR is inhibited. In the presence of DNA damages during late S and G2/M phase, inhibition of Rad51 pathway induced chromosomal aberrations, leading to a transient arrest in mitosis. This arrest is associated with an increased of cell death. However, a fraction of cells can escape from this transient arrest by forming tetraploid cells, associated with an absence of chromalid separation. Thus, in response to impaired Rad51 pathway, mitotic checkpoints seems to play an essential role. In line with this, we showed that the essential function of Rad51 is p53-dependent, which is in agreement with the role of p53 in tetraploidy inhibition. Our results suggest that the Rad51 protein could participate to the control of mitotic checkpoints and thus to the maintenance of genetic stability. This function could involve other Rad51 partners such as the tumour suppressors BRCA1, BRCA2 and p53. (author) [fr

  11. Tram system related cycling injuries.

    Science.gov (United States)

    Maempel, J F; Mackenzie, S P; Stirling, P H C; McCann, C; Oliver, C W; White, T O

    2018-01-24

    Understanding of tram-system related cycling injuries (TSRCI) is poor. The aim of this study was to report the spectrum of injuries, demographics and social deprivation status of patients. Secondary aims included assessment of accident circumstances, effects of TSRCI on patients' confidence cycling, together with time off work and cycling. A retrospective review of patients presenting to emergency services across all hospitals in Edinburgh and West Lothian with tram related injuries between May 2009 and April 2016 was undertaken. Medical records and imagining were analysed and patients were contacted by telephone. 191 cyclists (119 males, 72 females) were identified. 63 patients sustained one or more fractures or dislocations. Upper limb fractures/dislocations occurred in 55, lower limb fractures in 8 and facial fractures in 2. Most patients demonstrated low levels of socioeconomic deprivation. In 142 cases, the wheel was caught in tram-tracks, while in 32 it slid on tracks. The latter occurred more commonly in wet conditions (p = 0.028). 151 patients answered detailed questionnaires. Ninety-eight were commuting. 112 patients intended to cross tramlines and 65 accidents occurred at a junction. Eighty patients reported traffic pressures contributed to their accident. 120 stated that their confidence was affected and 24 did not resume cycling. Female gender (p < 0.001) and presence of a fracture/dislocation (p = 0.012) were independent predictors of negative effects on confidence. Patients sustaining a fracture/dislocation spent more time off work (median 5 days vs 1, p < 0.001) and cycling (median 57 days vs 21, p < 0.001). TSRCI occur predominantly in young to middle-aged adults with low levels of socioeconomic deprivation, most commonly when bicycle wheels get caught in tram-tracks. They result in various injuries, frequently affecting the upper limb. Traffic pressures are commonly implicated. Most patients report negative effects on confidence

  12. Fueling the Cell Division Cycle.

    Science.gov (United States)

    Salazar-Roa, María; Malumbres, Marcos

    2017-01-01

    Cell division is a complex process with high energy demands. However, how cells regulate the generation of energy required for DNA synthesis and chromosome segregation is not well understood. Recent data suggest that changes in mitochondrial dynamics and metabolic pathways such as oxidative phosphorylation (OXPHOS) and glycolysis crosstalk with, and are tightly regulated by, the cell division machinery. Alterations in energy availability trigger cell-cycle checkpoints, suggesting a bidirectional connection between cell division and general metabolism. Some of these connections are altered in human disease, and their manipulation may help in designing therapeutic strategies for specific diseases including cancer. We review here recent studies describing the control of metabolism by the cell-cycle machinery. Copyright © 2016 Elsevier Ltd. All rights reserved.

  13. Effects of low dose radiation on tumor apoptosis, cell cycle progression and changes of apoptosis-related protein bcl-2 in tumor-bearing mice

    International Nuclear Information System (INIS)

    Yu Hongsheng; Fei Conghe; Shen Fangzhen; Liang Jun

    2003-01-01

    Objective: To study the effect of low dose radiation (LDR) on tumor apoptosis, cell cycle progression and changes of apoptosis-related protein bcl-2 in tumor-bearing mice. Methods: Kunming stain male mice were implanted with S180 sarcoma cells in the left inguen subcutaneously as an in situ experimental animal model. Seven days after implantation, the mice were given 75 mGy whole-body γ-irradiation. At 24 and 48 h after irradiation, all mice were sacrificed to measure the tumor volume, and tumor cell apoptosis, cell cycle progression were analyzed by flow cytometry. The expression of apoptosis-related protein bcl-2 and the apoptotic rate of tumor cells were observed by immunohistochemistry and electron microscopy. Results: Tumor growth was significantly slowed down after LDR (P 1 phase and the expression of bcl-2 protein decreased at 24 h. Apoptotic rate of tumor cells increased significantly at 48 h after LDR. Conclusion: LDR could cause a G 1 -phase arrest and increase the apoptosis of tumor cells through the low level of apoptosis-related protein bcl-2 in the tumor-bearing mice. The organized immune function and anti-tumor ability are markedly increased after LDR. The study provides practical evidence of clinical application to cancer treatment

  14. Effects of in vitro exposure to diarrheic toxin producer Prorocentrum lima on gene expressions related to cell cycle regulation and immune response in Crassostrea gigas.

    Science.gov (United States)

    de Jesús Romero-Geraldo, Reyna; García-Lagunas, Norma; Hernández-Saavedra, Norma Yolanda

    2014-01-01

    Crassostrea gigas accumulates diarrheic shellfish toxins (DSP) associated to Prorocentrum lima of which Okadaic acid (OA) causes specific inhibitions of serine and threonine phosphatases 1 and 2A. Its toxic effects have been extensively reported in bivalve mollusks at cellular and physiological levels, but genomic approaches have been scarcely studied. Acute and sub-chronic exposure effects of P. lima were investigated on farmed juvenile C. gigas (3-5 mm). The Pacific oysters were fed with three dinoflagellate concentrations: 0.3, 3, and 30 ×10(3) cells mL-1 along with a nontoxic control diet of Isochrysis galbana. The effects of P. lima on C. gigas were followed by analyzing expression levels of a total of four genes, three involved in cell cycle regulation and one in immune response by polymerase chain reaction and real time quantitative PCR, where changes in time and cell concentration were found. The highest expression levels were found in oysters fed 3 × 10(3) cells mL-1 at 168 h for the cycle regulator p21 protein (9 fold), chromatin assembly factor 1 p55 subunit (8 fold), elongation factor 2 (2 fold), and lipopolysaccharide/β-1, 3 glucan binding protein (13 fold above base line). Additionally, the transcript level of all the genes decreased in oysters fed wich the mixed diet 30 × 10(3) cells mL-1 of dinoflagellate after 72 h and was lowest in the chromatin assembly factor 1 p55 subunit (0.9 fold below baseline). On C. gigas the whole cell ingestion of P lima caused a clear mRNA modulation expression of the genes involved in cell cycle regulation and immune system. Over-expression could be related to DNA damage, disturbances in cell cycle continuity, probably a genotoxic effect, as well as an activation of its innate immune system as first line of defense.

  15. Effects of in vitro exposure to diarrheic toxin producer Prorocentrum lima on gene expressions related to cell cycle regulation and immune response in Crassostrea gigas.

    Directory of Open Access Journals (Sweden)

    Reyna de Jesús Romero-Geraldo

    Full Text Available BACKGROUND: Crassostrea gigas accumulates diarrheic shellfish toxins (DSP associated to Prorocentrum lima of which Okadaic acid (OA causes specific inhibitions of serine and threonine phosphatases 1 and 2A. Its toxic effects have been extensively reported in bivalve mollusks at cellular and physiological levels, but genomic approaches have been scarcely studied. METHODOLOGY/PRINCIPAL FINDINGS: Acute and sub-chronic exposure effects of P. lima were investigated on farmed juvenile C. gigas (3-5 mm. The Pacific oysters were fed with three dinoflagellate concentrations: 0.3, 3, and 30 ×10(3 cells mL-1 along with a nontoxic control diet of Isochrysis galbana. The effects of P. lima on C. gigas were followed by analyzing expression levels of a total of four genes, three involved in cell cycle regulation and one in immune response by polymerase chain reaction and real time quantitative PCR, where changes in time and cell concentration were found. The highest expression levels were found in oysters fed 3 × 10(3 cells mL-1 at 168 h for the cycle regulator p21 protein (9 fold, chromatin assembly factor 1 p55 subunit (8 fold, elongation factor 2 (2 fold, and lipopolysaccharide/β-1, 3 glucan binding protein (13 fold above base line. Additionally, the transcript level of all the genes decreased in oysters fed wich the mixed diet 30 × 10(3 cells mL-1 of dinoflagellate after 72 h and was lowest in the chromatin assembly factor 1 p55 subunit (0.9 fold below baseline. CONCLUSIONS: On C. gigas the whole cell ingestion of P lima caused a clear mRNA modulation expression of the genes involved in cell cycle regulation and immune system. Over-expression could be related to DNA damage, disturbances in cell cycle continuity, probably a genotoxic effect, as well as an activation of its innate immune system as first line of defense.

  16. Structure related effects of flavonoid aglycones on cell cycle progression of HepG2 cells: Metabolic activation of fisetin and quercetin by catechol-O-methyltransferase (COMT).

    Science.gov (United States)

    Poór, Miklós; Zrínyi, Zita; Kőszegi, Tamás

    2016-10-01

    Dietary flavonoids are abundant in the Plant Kingdom and they are extensively studied because of their manifold pharmacological activities. Recent studies highlighted that cell cycle arrest plays a key role in their antiproliferative effect in different tumor cells. However, structure-activity relationship of flavonoids is poorly characterized. In our study the influence of 18 flavonoid aglycones (as well as two metabolites) on cell cycle distribution was investigated. Since flavonoids are extensively metabolized by liver cells, HepG2 tumor cell line was applied, considering the potential metabolic activation/inactivation of flavonoids. Our major observations are the followings: (1) Among the tested compounds diosmetin, fisetin, apigenin, lutelin, and quercetin provoked spectacular extent of G2/M phase cell cycle arrest. (2) Inhibition of catechol-O-methyltransferase enzyme by entacapone decreased the antiproliferative effects of fisetin and quercetin. (3) Geraldol and isorhamnetin (3'-O-methylated metabolites of fisetin and quercetin, respectively) demonstrated significantly higher antiproliferative effect on HepG2 cells compared to the parent compounds. Based on these results, O-methylated flavonoid metabolites or their chemically modified derivatives may be suitable candidates of tumor therapy in the future. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

  17. Cell cycle control across the eukaryotic kingdom.

    Science.gov (United States)

    Harashima, Hirofumi; Dissmeyer, Nico; Schnittger, Arp

    2013-07-01

    Almost two billion years of evolution have generated a vast and amazing variety of eukaryotic life with approximately 8.7 million extant species. Growth and reproduction of all of these organisms depend on faithful duplication and distribution of their chromosomes to the newly forming daughter cells in a process called the cell cycle. However, most of what is known today about cell cycle control comes from a few model species that belong to the unikonts; that is, to only one of five 'supergroups' that comprise the eukaryotic kingdom. Recently, analyzing species from distantly related clades is providing insights into general principles of cell cycle regulation and shedding light on its evolution. Here, referring to animal and fungal as opposed to non-unikont systems, especially flowering plants from the archaeplastid supergroup, we compare the conservation of central cell cycle regulator functions, the structure of network topologies, and the evolutionary dynamics of substrates of core cell cycle kinases. Copyright © 2013 Elsevier Ltd. All rights reserved.

  18. Dynamic changes in the genomic localization of DNA replication-related element binding factor during the cell cycle.

    Science.gov (United States)

    Gurudatta, B V; Yang, Jingping; Van Bortle, Kevin; Donlin-Asp, Paul G; Corces, Victor G

    2013-05-15

    DREF was first characterized for its role in the regulation of transcription of genes encoding proteins involved in DNA replication and found to interact with sequences similar to the DNA recognition motif of the BEAF-32 insulator protein. Insulators are DNA-protein complexes that mediate intra- and inter-chromosome interactions. Several DNA-binding insulator proteins have been described in Drosophila, including BEAF-32, dCTCF and Su(Hw). Here we find that DREF and BEAF-32 co-localize at the same genomic sites, but their enrichment shows an inverse correlation. Furthermore, DREF co-localizes in the genome with other insulator proteins, suggesting that the function of this protein may require components of Drosophila insulators. This is supported by the finding that mutations in insulator proteins modulate DREF-induced cell proliferation. DREF persists bound to chromatin during mitosis at a subset of sites where it also co-localizes with dCTCF, BEAF-32 and CP190. These sites are highly enriched for sites where Orc2 and Mcm2 are present during interphase and at the borders of topological domains of chromosomes defined by Hi-C. The results suggest that DREF and insulator proteins may help maintain chromosome organization during the cell cycle and mark a subset of genomic sites for the assembly of pre-replication complexes and gene bookmarking during the M/G1 transition.

  19. In Vitro Antiproliferative Effect of Arthrocnemum indicum Extracts on Caco-2 Cancer Cells through Cell Cycle Control and Related Phenol LC-TOF-MS Identification

    Directory of Open Access Journals (Sweden)

    Mondher Boulaaba

    2013-01-01

    Full Text Available This study aimed to determinate phenolic contents and antioxidant activities of the halophyte Arthrocnemum indicum shoot extracts. Moreover, the anticancer effect of this plant on human colon cancer cells and the likely underlying mechanisms were also investigated, and the major phenols were identified by LC-ESI-TOF-MS. Results showed that shoot extracts had an antiproliferative effect of about 55% as compared to the control and were characterised by substantial total polyphenol content (19 mg GAE/g DW and high antioxidant activity (IC50=40 μg/mL for DPPH test. DAPI staining revealed that these extracts decrease DNA synthesis and reduce the proliferation of Caco-2 cells which were stopped at the G2/M phase. The changes in the cell-cycle-associated proteins (cyclin B1, p38, Erk1/2, Chk1, and Chk2 correlate with the changes in cell cycle distribution. Eight phenolic compounds were also identified. In conclusion, A. indicum showed interesting antioxidant capacities associated with a significant antiproliferative effect explained by a cell cycle blocking at the G2/M phase. Taken together, these data suggest that A. indicum could be a promising candidate species as a source of anticancer molecules.

  20. Virus manipulation of cell cycle.

    Science.gov (United States)

    Nascimento, R; Costa, H; Parkhouse, R M E

    2012-07-01

    Viruses depend on host cell resources for replication and access to those resources may be limited to a particular phase of the cell cycle. Thus manipulation of cell cycle is a commonly employed strategy of viruses for achieving a favorable cellular environment. For example, viruses capable of infecting nondividing cells induce S phase in order to activate the host DNA replication machinery and provide the nucleotide triphosphates necessary for viral DNA replication (Flemington in J Virol 75:4475-4481, 2001; Sullivan and Pipas in Microbiol Mol Biol Rev 66:179-202, 2002). Viruses have developed several strategies to subvert the cell cycle by association with cyclin and cyclin-dependent kinase complexes and molecules that regulate their activity. Viruses tend to act on cellular proteins involved in a network of interactions in a way that minimal protein-protein interactions lead to a major effect. The complex and interactive nature of intracellular signaling pathways controlling cell division affords many opportunities for virus manipulation strategies. Taking the maxim "Set a thief to catch a thief" as a counter strategy, however, provides us with the very same virus evasion strategies as "ready-made tools" for the development of novel antivirus therapeutics. The most obvious are attenuated virus vaccines with critical evasion genes deleted. Similarly, vaccines against viruses causing cancer are now being successfully developed. Finally, as viruses have been playing chess with our cell biology and immune responses for millions of years, the study of their evasion strategies will also undoubtedly reveal new control mechanisms and their corresponding cellular intracellular signaling pathways.

  1. Apoptosis Induction by Polygonum minus Is Related to Antioxidant Capacity, Alterations in Expression of Apoptotic-Related Genes, and S-Phase Cell Cycle Arrest in HepG2 Cell Line

    Directory of Open Access Journals (Sweden)

    Mohd Alfazari Mohd Ghazali

    2014-01-01

    Full Text Available Polygonum minus (Polygonaceae is a medicinal herb distributed throughout eastern Asia. The present study investigated antiproliferative effect of P. minus and its possible mechanisms. Four extracts (petroleum ether, methanol, ethyl acetate, and water were prepared by cold maceration. Extracts were subjected to phytochemical screening, antioxidant, and antiproliferative assays; the most bioactive was fractionated using vacuum liquid chromatography into seven fractions (F1–F7. Antioxidant activity was measured via total phenolic content (TPC, 2,2-diphenyl-1-picrylhydrazyl (DPPH, and ferric reducing antioxidant power (FRAP assays. Antiproliferative activity was evaluated using 3-(4,5-dimethylthiazol-2-yl-2,5-diphenyltetrazolium bromide (MTT assay. Most active fraction was tested for apoptosis induction and cell cycle arrest in HepG2 cells using flow cytometry and confocal microscopy. Apoptotic-related gene expression was studied by RT-PCR. Ethyl acetate extract was bioactive in initial assays. Its fraction, F7, exhibited highest antioxidant capacity (TPC; 113.16±6.2 mg GAE/g extract, DPPH; EC50: 30.5±3.2 μg/mL, FRAP; 1169±20.3 μmol Fe (II/mg extract and selective antiproliferative effect (IC50: 25.75±1.5 μg/mL. F7 induced apoptosis in concentration- and time-dependent manner and caused cell cycle arrest at S-phase. Upregulation of proapoptotic genes (Bax, p53, and caspase-3 and downregulation of antiapoptotic gene, Bcl-2, were observed. In conclusion, F7 was antiproliferative to HepG2 cells by inducing apoptosis, cell cycle arrest, and via antioxidative effects.

  2. Methoxychlor and triclosan stimulates ovarian cancer growth by regulating cell cycle- and apoptosis-related genes via an estrogen receptor-dependent pathway.

    Science.gov (United States)

    Kim, Joo-Young; Yi, Bo-Rim; Go, Ryeo-Eun; Hwang, Kyung-A; Nam, Ki-Hoan; Choi, Kyung-Chul

    2014-05-01

    Methoxychlor and triclosan are emergent or suspected endocrine-disrupting chemicals (EDCs). Methoxychlor [MXC; 1,1,1-trichlor-2,2-bis (4-methoxyphenyl) ethane] is an organochlorine pesticide that has been primarily used since dichlorodiphenyltrichloroethane (DDT) was banned. In addition, triclosan (TCS) is used as a common component of soaps, deodorants, toothpastes, and other hygiene products at concentrations up to 0.3%. In the present study, the potential impact of MXC and TCS on ovarian cancer cell growth and underlying mechanism(s) was examined following their treatments in BG-1 ovarian cancer cells. As results, MXC and TCS induced BG-1 cell growth via regulating cyclin D1, p21 and Bax genes related with cell cycle and apoptosis. A methylthiazolyldiphenyl-tetrazolium bromide (MTT) assay confirmed that the proliferation of BG-1 ovarian cancer cells was stimulated by MXC (10(-6), 10(-7), 10(-8), and 10(-9)M) or TCS (10(-6), 10(-7), 10(-8), and 10(-9)M). Treatment of BG-1 cells with MXC or TCS resulted in the upregulation of cyclin D1 and downregulation of p21 and Bax transcriptions. In addition, the protein level of cyclin D1 was increased by MXC or TCS while p21 and Bax protein levels appeared to be reduced in these cells. Furthermore, MXC- or TCS-induced alterations of these genes were reversed in the presence of ICI 182,780 (10(-7)M), suggesting that the changes in these gene expressions may be regulated by an ER-dependent signaling pathway. In conclusion, the results of our investigation indicate that two potential EDCs, MXC and TCS, may stimulate ovarian cancer growth by regulating cell cycle- and apoptosis-related genes via an ER-dependent pathway. Copyright © 2014 Elsevier B.V. All rights reserved.

  3. Cell cycle regulation of hematopoietic stem or progenitor cells.

    Science.gov (United States)

    Hao, Sha; Chen, Chen; Cheng, Tao

    2016-05-01

    The highly regulated process of blood production is achieved through the hierarchical organization of hematopoietic stem cell (HSC) subsets and their progenies, which differ in self-renewal and differentiation potential. Genetic studies in mice have demonstrated that cell cycle is tightly controlled by the complex interplay between extrinsic cues and intrinsic regulatory pathways involved in HSC self-renewal and differentiation. Deregulation of these cellular programs may transform HSCs or hematopoietic progenitor cells (HPCs) into disease-initiating stem cells, and can result in hematopoietic malignancies such as leukemia. While previous studies have shown roles for some cell cycle regulators and related signaling pathways in HSCs and HPCs, a more complete picture regarding the molecular mechanisms underlying cell cycle regulation in HSCs or HPCs is lacking. Based on accumulated studies in this field, the present review introduces the basic components of the cell cycle machinery and discusses their major cellular networks that regulate the dormancy and cell cycle progression of HSCs. Knowledge on this topic would help researchers and clinicians to better understand the pathogenesis of relevant blood disorders and to develop new strategies for therapeutic manipulation of HSCs.

  4. Multi-tasking Sulf1/Sulf2 enzymes do not only facilitate extracellular cell signalling but also participate in cell cycle related nuclear events.

    Science.gov (United States)

    Krishnakumar, Kavithanjali; Chakravorty, Ishani; Foy, Wendy; Allen, Steve; Justo, Tiago; Mukherjee, Abir; Dhoot, Gurtej K

    2018-03-01

    This study demonstrates highly dynamic spatial and temporal pattern of SULF1/SULF2 expression in a number of neuronal cell types growing in normal culture medium that included their transient nuclear mobilisation. Their nuclear translocation became particularly apparent during cell proliferation as both SULF1/SULF2 demonstrated not only cell membrane associated expression, their known site of function but also transient nuclear mobilisation during nuclear cell division. Nuclear localisation was apparent not only by immunocytochemical staining but also confirmed by immunoblotting staining of isolated nuclear fractions of C6, U87 and N2A cells. Immunocytochemical analysis demonstrated rapid nuclear exit of both SULF1/SULF2 following cell division that was slightly delayed but not blocked in a fraction of the polyploid cells observed in C6 cells. The overexpression of both Sulf1 and Sulf2 genes in C6 and U87 cells markedly promoted in vitro growth of these cells accompanied by nuclear mobilisation while inhibition of both these genes inhibited cell proliferation with little or no nuclear SULF1/SULF2 mobilisation. SULF1/SULF2 activity in these cells thus demonstrated a clear co-ordination of extracellular cell signalling with nuclear events related to cell proliferation. Crown Copyright © 2018. Published by Elsevier Inc. All rights reserved.

  5. 17-AAG mediated targeting of Hsp90 limits tert activity in peritoneal sarcoma related malignant ascites by downregulating cyclin D1 during cell cycle entry.

    Science.gov (United States)

    Chaklader, M; Das, P; Pereira, J A; Law, A; Chattopadhyay, S; Chatterjee, R; Mondal, A; Law, S

    2012-07-01

    Peritoneal or retro-peritoneal sarcomatosis related malignant ascites formation is a rare but serious consequence of the locoregional metastatic event. The present work aimed to study the effect of the Hsp90 inhibitor (17-AAG), an ansamycin analog, on cell cycle and DNA replication specific chaperone-clients interaction in the event of peritoneal sarcoma related malignant ascites formation in mouse model at the late stage of malignant growth. We administered 17-AAG, an Hsp90 inhibitor, divided doses (330 μg/kg b.w./day for first five days then next ten days with166 μg/kg b.w./day) through intra-peritoneal route of inbred Swiss albino mice bearing full grown peritoneal malignant ascites of sarcoma-180. Our study was evaluated by peripheral blood hemogram analysis, malignant ascitic cytology, cell viability test, survival time and mitotic indexing. Furthermore, flowcytometric HSP90, TERT, CyclinD1, PCNA and GM-CSF expression analysis has been considered for special objective of the study. Our experimental efforts reduced the aggressive proliferation of malignant ascites by drastic downregulation of TERT and cyclin D1 on the verge of cell cycle entry along with DNA replication processivity factor PCNA by directly modulating their folding machinery - heat shock protein 90. Consequently, we observed that malignant ascitic cells became error prone during the event of karyokinesis and produced micronucleus containing malignant cells with low viability. Peripheral neutrophilia due to over-expression of GM-CSF by the peritoneal malignant ascites were also controlled by the treatment with 17-AAG and overall, the treatment modality improved the median survival time. Finally we can conclude that 17AAG administration might serve as a prospective pharmacological agent for the management of peritoneal sarcoma related malignant ascites and throws light towards prolonged survival of the patients concerned.

  6. Subversion of Cell Cycle Regulatory Mechanisms by HIV

    OpenAIRE

    Rice, Andrew P.; Kimata, Jason T.

    2015-01-01

    To establish a productive infection, HIV-1 must counteract cellular innate immune mechanisms and redirect cellular process towards viral replication. Recent studies have discovered that HIV-1 and other primate immunodeficiency viruses subvert cell cycle regulatory mechanisms to achieve these ends. The viral Vpr and Vpx proteins target cell cycle controls to counter innate immunity. The cell cycle-related protein Cyclin L2 is also utilized to counter innate immunity. The viral Tat protein util...

  7. "Constructing" the Cell Cycle in 3D

    Science.gov (United States)

    Koc, Isil; Turan, Merve

    2012-01-01

    The cycle of duplication and division, known as the "cell cycle," is the essential mechanism by which all living organisms reproduce. This activity allows students to develop an understanding of the main events that occur during the typical eukaryotic cell cycle mostly in the process of mitotic phase that divides the duplicated genetic material…

  8. Transcriptional profiling of arbuscular mycorrhizal roots exposed to high levels of phosphate reveals the repression of cell cycle-related genes and secreted protein genes in Rhizophagus irregularis.

    Science.gov (United States)

    Sugimura, Yusaku; Saito, Katsuharu

    2017-02-01

    The development of arbuscular mycorrhiza (AM) is strongly suppressed under high-phosphate (Pi) conditions. To investigate AM fungal responses during the suppression of AM by high Pi, we performed an RNA-seq analysis of Rhizophagus irregularis colonizing Lotus japonicus roots at different levels of Pi (20, 100, 300, and 500 μM). AM fungal colonization decreased markedly under high-Pi conditions. In total, 163 fungal genes were differentially expressed among the four Pi treatments. Among these genes, a cell cycle-regulatory gene, cyclin-dependent kinase CDK1, and several DNA replication- and mitosis-related genes were repressed under high-Pi conditions. More than 20 genes encoding secreted proteins were also downregulated by high-Pi conditions, including the strigolactone-induced putative secreted protein 1 gene that enhances AM fungal colonization. In contrast, the expression of genes related to aerobic respiration and transport in R. irregularis were largely unaffected. Our data suggest that high Pi suppresses the expression of genes associated with fungal cell cycle progression or that encode secreted proteins that may be required for intercellular hyphal growth and arbuscule formation. However, high Pi has little effect on the transcriptional regulation of the primary metabolism or transport in preformed fungal structures.

  9. Epigenetic dynamics across the cell cycle

    DEFF Research Database (Denmark)

    Kheir, Tony Bou; Lund, Anders H.

    2010-01-01

    Progression of the mammalian cell cycle depends on correct timing and co-ordination of a series of events, which are managed by the cellular transcriptional machinery and epigenetic mechanisms governing genome accessibility. Epigenetic chromatin modifications are dynamic across the cell cycle...... a correct inheritance of epigenetic chromatin modifications to daughter cells. In this chapter, we summarize the current knowledge on the dynamics of epigenetic chromatin modifications during progression of the cell cycle....

  10. Cell division cycle 45 promotes papillary thyroid cancer progression via regulating cell cycle.

    Science.gov (United States)

    Sun, Jing; Shi, Run; Zhao, Sha; Li, Xiaona; Lu, Shan; Bu, Hemei; Ma, Xianghua

    2017-05-01

    Cell division cycle 45 was reported to be overexpressed in some cancer-derived cell lines and was predicted to be a candidate oncogene in cervical cancer. However, the clinical and biological significance of cell division cycle 45 in papillary thyroid cancer has never been investigated. We determined the expression level and clinical significance of cell division cycle 45 using The Cancer Genome Atlas, quantitative real-time polymerase chain reaction, and immunohistochemistry. A great upregulation of cell division cycle 45 was observed in papillary thyroid cancer tissues compared with adjacent normal tissues. Furthermore, overexpression of cell division cycle 45 positively correlates with more advanced clinical characteristics. Silence of cell division cycle 45 suppressed proliferation of papillary thyroid cancer cells via G1-phase arrest and inducing apoptosis. The oncogenic activity of cell division cycle 45 was also confirmed in vivo. In conclusion, cell division cycle 45 may serve as a novel biomarker and a potential therapeutic target for papillary thyroid cancer.

  11. Molecular mechanisms controlling the cell cycle in embryonic stem cells.

    Science.gov (United States)

    Abdelalim, Essam M

    2013-12-01

    Embryonic stem (ES) cells are originated from the inner cell mass of a blastocyst stage embryo. They can proliferate indefinitely, maintain an undifferentiated state (self-renewal), and differentiate into any cell type (pluripotency). ES cells have an unusual cell cycle structure, consists mainly of S phase cells, a short G1 phase and absence of G1/S checkpoint. Cell division and cell cycle progression are controlled by mechanisms ensuring the accurate transmission of genetic information from generation to generation. Therefore, control of cell cycle is a complicated process, involving several signaling pathways. Although great progress has been made on the molecular mechanisms involved in the regulation of ES cell cycle, many regulatory mechanisms remain unknown. This review summarizes the current knowledge about the molecular mechanisms regulating the cell cycle of ES cells and describes the relationship existing between cell cycle progression and the self-renewal.

  12. Tumor Suppressors and Cell-Cycle Proteins in Lung Cancer

    Directory of Open Access Journals (Sweden)

    Alfonso Baldi

    2011-01-01

    Full Text Available The cell cycle is the cascade of events that allows a growing cell to duplicate all its components and split into two daughter cells. Cell cycle progression is mediated by the activation of a highly conserved family of protein kinases, the cyclin-dependent kinases (CDKs. CDKs are also regulated by related proteins called cdk inhibitors grouped into two families: the INK4 inhibitors (p16, p15, p19, and p18 and the Cip/Kip inhibitors (p21, p27, and p53. Several studies report the importance of cell-cycle proteins in the pathogenesis and the prognosis of lung cancer. This paper will review the most recent data from the literature about the regulation of cell cycle. Finally, based essentially on the data generated in our laboratory, the expression, the diagnostic, and prognostic significance of cell-cycle molecules in lung cancer will be examined.

  13. Role of Protein Phosphorylation in the Regulation of Cell Cycle and DNA-Related Processes in Bacteria

    DEFF Research Database (Denmark)

    Garcia-Garcia, Transito; Poncet, Sandrine; Derouiche, Abderahmane

    2016-01-01

    In all living organisms, the phosphorylation of proteins modulates various aspects of their functionalities. In eukaryotes, protein phosphorylation plays a key role in cell signaling, gene expression, and differentiation. Protein phosphorylation is also involved in the global control of DNA repli...

  14. Cell cycle control by components of cell anchorage

    OpenAIRE

    Gad, Annica

    2005-01-01

    Extracellular factors, such as growth factors and cell anchorage to the extracellular matrix, control when and where cells may proliferate. This control is abolished when a normal cell transforms into a tumour cell. The control of cell proliferation by cell anchorage was elusive and less well studied than the control by growth factors. Therefore, we aimed to clarify at what points in the cell cycle and through which molecular mechanisms cell anchorage controls cell cycle pro...

  15. Stretched cell cycle model for proliferating lymphocytes

    Science.gov (United States)

    Dowling, Mark R.; Kan, Andrey; Heinzel, Susanne; Zhou, Jie H. S.; Marchingo, Julia M.; Wellard, Cameron J.; Markham, John F.; Hodgkin, Philip D.

    2014-01-01

    Stochastic variation in cell cycle time is a consistent feature of otherwise similar cells within a growing population. Classic studies concluded that the bulk of the variation occurs in the G1 phase, and many mathematical models assume a constant time for traversing the S/G2/M phases. By direct observation of transgenic fluorescent fusion proteins that report the onset of S phase, we establish that dividing B and T lymphocytes spend a near-fixed proportion of total division time in S/G2/M phases, and this proportion is correlated between sibling cells. This result is inconsistent with models that assume independent times for consecutive phases. Instead, we propose a stretching model for dividing lymphocytes where all parts of the cell cycle are proportional to total division time. Data fitting based on a stretched cell cycle model can significantly improve estimates of cell cycle parameters drawn from DNA labeling data used to monitor immune cell dynamics. PMID:24733943

  16. Lactobacillus decelerates cervical epithelial cell cycle progression.

    Directory of Open Access Journals (Sweden)

    Katarina Vielfort

    Full Text Available We investigated cell cycle progression in epithelial cervical ME-180 cells during colonization of three different Lactobacillus species utilizing live cell microscopy, bromodeoxyuridine incorporation assays, and flow cytometry. The colonization of these ME-180 cells by L. rhamnosus and L. reuteri, originating from human gastric epithelia and saliva, respectively, was shown to reduce cell cycle progression and to cause host cells to accumulate in the G1 phase of the cell cycle. The G1 phase accumulation in L. rhamnosus-colonized cells was accompanied by the up-regulation and nuclear accumulation of p21. By contrast, the vaginal isolate L. crispatus did not affect cell cycle progression. Furthermore, both the supernatants from the lactic acid-producing L. rhamnosus colonies and lactic acid added to cell culture media were able to reduce the proliferation of ME-180 cells. In this study, we reveal the diversity of the Lactobacillus species to affect host cell cycle progression and demonstrate that L. rhamnosus and L. reuteri exert anti-proliferative effects on human cervical carcinoma cells.

  17. Cell cycle entry in C. elegans development

    NARCIS (Netherlands)

    Korzelius, J.P.

    2010-01-01

    Cell division is controlled by a mechanism that uses Cyclins, in association with their Cyclin-dependent kinase partners (Cdk’s), to regulate the transitions in the cell cycle.Studies in mammalian cell culture and single cell eukaryotes such as budding and fission yeast have uncovered much about how

  18. Developmental kinetics of the first cell cycles of bovine in vitro produced embryos in relation to their in vitro viability and sex

    DEFF Research Database (Denmark)

    Holm, Peter; Shukri, N. M.; Vajta, Gábor

    1998-01-01

    The development of bovine IVP-embryos was observed in a time-lapse culture system to determine cell cycle lengths of 1) embryos that developed into compact morulae (CM) or blastocysts (BL) within 174 h after insemination (viable), 2) embryos that arrested during earlier stages (nonviable) and 3...... were included (n=392), and the times of cleavage events noted. After culture, 100 CM or BL were randomly selected for sexing by PCR. BL developed equally well in the time-lapse and control culture systems (36 vs 38. The respective lengths of the first 4 cell cycles of viable embryos were 32.0 + 3.9, g...

  19. Cell cycle control factors and skeletal development

    Directory of Open Access Journals (Sweden)

    Toru Ogasawara

    2013-05-01

    Full Text Available In the oral and maxillofacial region, conditions such as delayed bone healing after tooth extraction, bone fracture, trauma-induced bone or cartilage defects, and tumors or birth defects are common, and it is necessary to identify the molecular mechanisms that control skeletogenesis or the differentiation of cells, in order to establish new treatment strategies for these conditions. Multiple studies have been conducted to investigate the involvement of factors that may be crucial for skeletogenesis or the differentiation of cells, including transcription factors, growth factors and cell cycle factors. Several genetically engineered mouse models of cell cycle factors have been generated in research seeking to identify cell cycle factor(s involved in the differentiation of cells, carcinogenesis, etc. Many groups have also reported the importance of cell cycle factors in the differentiation of osteoblasts, osteoclasts, chondrocytes and other cell types. Herein, we review the phenotypes of the genetically engineered mouse models of cell cycle factors with a particular focus on the size, body weight and skeletal abnormalities of the mice, and we discuss the potential of cell cycle factors as targets of clinical applications.

  20. Cell cycle checkpoints: methods and protocols

    Directory of Open Access Journals (Sweden)

    Carlo Alberto Redi

    2012-09-01

    Full Text Available As it is well known at the end of each cell cycle step there are checkpoints to verify that DNA duplication and segregation (among other events met every requirements before the cell is allowed to proceed to the next step. Multiple signaling molecules, notably cyclins and the cyclin-dependent kinases (CDKs, play major roles in the cell cycle checkpoint’s control....

  1. Endothelial cell subpopulations in vitro: cell volume, cell cycle, and radiosensitivity

    International Nuclear Information System (INIS)

    Rubin, D.B.; Drab, E.A.; Bauer, K.D.

    1989-01-01

    Vascular endothelial cells (EC) are important clinical targets of radiation and other forms of free radical/oxidant stresses. In this study, we found that the extent of endothelial damage may be determined by the different cytotoxic responses of EC subpopulations. The following characteristics of EC subpopulations were examined: (1) cell volume; (2) cell cycle position; and (3) cytotoxic indexes for both acute cell survival and proliferative capacity after irradiation (137Cs, gamma, 0-10 Gy). EC cultured from bovine aortas were separated by centrifugal elutriation into subpopulations of different cell volumes. Through flow cytometry, we found that cell volume was related to the cell cycle phase distribution. The smallest EC were distributed in G1 phase and the larger cells were distributed in either early S, middle S, or late S + G2M phases. Cell cycle phase at the time of irradiation was not associated with acute cell loss. However, distribution in the cell cycle did relate to cell survival based on proliferative capacity (P less than 0.01). The order of increasing radioresistance was cells in G1 (D0 = 110 cGy), early S (135 cGy), middle S (145 cGy), and late S + G2M phases (180 cGy). These findings (1) suggest an age-related response to radiation in a nonmalignant differentiated cell type and (2) demonstrate EC subpopulations in culture

  2. Regulation of the cell cycle by irradiation

    International Nuclear Information System (INIS)

    Akashi, Makoto

    1995-01-01

    The molecular mechanism of cell proliferation is extremely complex; deregulation results in neoplastic transformation. In eukaryotes, proliferation of cells is finely regulated through the cell cycle. Studies have shown that the cell cycle is regulated by s series of enzymes known as cyclin-dependent kinases (CDKs). The activities of CDKs are controlled by their association with regulatory subunits, cyclins; the expression of cyclins and the activation of the different cyclin-CDK complexes are required for the cell to cycle. Thus, the cell cycle is regulated by activating and inhibiting phosphorylation of the CDK subunits and this program has internal check points at different stages of the cell cycle. When cells are exposed to external insults such as DNA damaging agents, negative regulation of the cell cycle occurs; arrest in either G1 or G2 stage is induced to prevent the cells from prematurely entering into the next stage before DNA is repaired. Recently, a potent inhibitor of CDKs, which inhibits the phosphorylation of retinoblastoma susceptibility (Rb) gene product by cyclin A-CDK2, cyclin E-CDK2, cyclin D1-CDK4, and cyclin D2-CDK4 complexes has been identified. This protein named WAF1, Sdi1, Cip1, or p21 (a protein of Mr 21,000) contains a p53-binding site in its promoter and studies have reported that the expression of WAF1 was directly regulated by p53; cells with loss of p53 activity due to mutational alteration were unable to induce WAF1. This chapter will be focused on the mechanisms of the cell cycle including inhibitors of CDKs, and the induction of WAF1 by irradiation through a pathway independent of p53 will be also described. (author)

  3. Regulation of the cell cycle by irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Akashi, Makoto [National Inst. of Radiological Sciences, Chiba (Japan)

    1995-12-01

    The molecular mechanism of cell proliferation is extremely complex; deregulation results in neoplastic transformation. In eukaryotes, proliferation of cells is finely regulated through the cell cycle. Studies have shown that the cell cycle is regulated by s series of enzymes known as cyclin-dependent kinases (CDKs). The activities of CDKs are controlled by their association with regulatory subunits, cyclins; the expression of cyclins and the activation of the different cyclin-CDK complexes are required for the cell to cycle. Thus, the cell cycle is regulated by activating and inhibiting phosphorylation of the CDK subunits and this program has internal check points at different stages of the cell cycle. When cells are exposed to external insults such as DNA damaging agents, negative regulation of the cell cycle occurs; arrest in either G1 or G2 stage is induced to prevent the cells from prematurely entering into the next stage before DNA is repaired. Recently, a potent inhibitor of CDKs, which inhibits the phosphorylation of retinoblastoma susceptibility (Rb) gene product by cyclin A-CDK2, cyclin E-CDK2, cyclin D1-CDK4, and cyclin D2-CDK4 complexes has been identified. This protein named WAF1, Sdi1, Cip1, or p21 (a protein of Mr 21,000) contains a p53-binding site in its promoter and studies have reported that the expression of WAF1 was directly regulated by p53; cells with loss of p53 activity due to mutational alteration were unable to induce WAF1. This chapter will be focused on the mechanisms of the cell cycle including inhibitors of CDKs, and the induction of WAF1 by irradiation through a pathway independent of p53 will be also described. (author)

  4. Cell cycle activation by plant parasitic nematodes

    NARCIS (Netherlands)

    Goverse, A.; Almeida Engler, de J.; Verhees, J.; Krol, van der S.; Helder, J.; Gheysen, G.

    2000-01-01

    Sedentary nematodes are important pests of crop plants. They are biotrophic parasites that can induce the (re)differentiation of either differentiated or undifferentiated plant cells into specialized feeding cells. This (re)differentiation includes the reactivation of the cell cycle in specific

  5. Transcriptional landscape of the human cell cycle.

    Science.gov (United States)

    Liu, Yin; Chen, Sujun; Wang, Su; Soares, Fraser; Fischer, Martin; Meng, Feilong; Du, Zhou; Lin, Charles; Meyer, Clifford; DeCaprio, James A; Brown, Myles; Liu, X Shirley; He, Housheng Hansen

    2017-03-28

    Steady-state gene expression across the cell cycle has been studied extensively. However, transcriptional gene regulation and the dynamics of histone modification at different cell-cycle stages are largely unknown. By applying a combination of global nuclear run-on sequencing (GRO-seq), RNA sequencing (RNA-seq), and histone-modification Chip sequencing (ChIP-seq), we depicted a comprehensive transcriptional landscape at the G0/G1, G1/S, and M phases of breast cancer MCF-7 cells. Importantly, GRO-seq and RNA-seq analysis identified different cell-cycle-regulated genes, suggesting a lag between transcription and steady-state expression during the cell cycle. Interestingly, we identified genes actively transcribed at early M phase that are longer in length and have low expression and are accompanied by a global increase in active histone 3 lysine 4 methylation (H3K4me2) and histone 3 lysine 27 acetylation (H3K27ac) modifications. In addition, we identified 2,440 cell-cycle-regulated enhancer RNAs (eRNAs) that are strongly associated with differential active transcription but not with stable expression levels across the cell cycle. Motif analysis of dynamic eRNAs predicted Kruppel-like factor 4 (KLF4) as a key regulator of G1/S transition, and this identification was validated experimentally. Taken together, our combined analysis characterized the transcriptional and histone-modification profile of the human cell cycle and identified dynamic transcriptional signatures across the cell cycle.

  6. Protein migration from transplanted nuclei in Amoeba proteus. I. The relation to the cell cycle and RNA migration, as studied by autoradiography

    Energy Technology Data Exchange (ETDEWEB)

    Mills, K.I.; Bell, L.G.

    1982-11-01

    Autoradiography has been used to examine the migration of proteins from a radioactivity labelled amoeba nucleus following transplantation into an unlabelled homophasic amoeba. Nuclei were transferred at three times in the cell cycle coinciding with DNA synthesis (4 h post-division); a peak of RNA synthesis (25 h); and a relative lull in synthetic activity (43 h). Six amino acids were added individually to the culture medium to label the nuclear proteins. Migration of the proteins from the donor nucleui and least with proteins labelled with the basic amino acids. All amino acids exhibited the greatest extent of migration following the 25-h transfers, i.e., coinciding with a peak of RNA synthesis at 26-27.5 h. Actinomycin D (actD) inhibition of RNA synthesis reduced, but did not eliminate the extent of protein migration from the transplanted nucleus, thus indicating the existence of two classes of migratory proteins. Firstly, proteins, associated with RNA transport, which migrated mainly into the host cytoplasm. The second class migrated into the host nucleus from the transplanted nucleus, irrespective of RNA synthesis. The shuttling character of the latter class of proteins is consistent with a role of regulation of nuclear activity.

  7. Cell-cycle inhibition by Helicobacter pylori L-asparaginase.

    Directory of Open Access Journals (Sweden)

    Claudia Scotti

    Full Text Available Helicobacter pylori (H. pylori is a major human pathogen causing chronic gastritis, peptic ulcer, gastric cancer, and mucosa-associated lymphoid tissue lymphoma. One of the mechanisms whereby it induces damage depends on its interference with proliferation of host tissues. We here describe the discovery of a novel bacterial factor able to inhibit the cell-cycle of exposed cells, both of gastric and non-gastric origin. An integrated approach was adopted to isolate and characterise the molecule from the bacterial culture filtrate produced in a protein-free medium: size-exclusion chromatography, non-reducing gel electrophoresis, mass spectrometry, mutant analysis, recombinant protein expression and enzymatic assays. L-asparaginase was identified as the factor responsible for cell-cycle inhibition of fibroblasts and gastric cell lines. Its effect on cell-cycle was confirmed by inhibitors, a knockout strain and the action of recombinant L-asparaginase on cell lines. Interference with cell-cycle in vitro depended on cell genotype and was related to the expression levels of the concurrent enzyme asparagine synthetase. Bacterial subcellular distribution of L-asparaginase was also analysed along with its immunogenicity. H. pylori L-asparaginase is a novel antigen that functions as a cell-cycle inhibitor of fibroblasts and gastric cell lines. We give evidence supporting a role in the pathogenesis of H. pylori-related diseases and discuss its potential diagnostic application.

  8. Cell-Cycle Inhibition by Helicobacter pylori L-Asparaginase

    Science.gov (United States)

    Scotti, Claudia; Sommi, Patrizia; Pasquetto, Maria Valentina; Cappelletti, Donata; Stivala, Simona; Mignosi, Paola; Savio, Monica; Chiarelli, Laurent Roberto; Valentini, Giovanna; Bolanos-Garcia, Victor M.; Merrell, Douglas Scott; Franchini, Silvia; Verona, Maria Luisa; Bolis, Cristina; Solcia, Enrico; Manca, Rachele; Franciotta, Diego; Casasco, Andrea; Filipazzi, Paola; Zardini, Elisabetta; Vannini, Vanio

    2010-01-01

    Helicobacter pylori (H. pylori) is a major human pathogen causing chronic gastritis, peptic ulcer, gastric cancer, and mucosa-associated lymphoid tissue lymphoma. One of the mechanisms whereby it induces damage depends on its interference with proliferation of host tissues. We here describe the discovery of a novel bacterial factor able to inhibit the cell-cycle of exposed cells, both of gastric and non-gastric origin. An integrated approach was adopted to isolate and characterise the molecule from the bacterial culture filtrate produced in a protein-free medium: size-exclusion chromatography, non-reducing gel electrophoresis, mass spectrometry, mutant analysis, recombinant protein expression and enzymatic assays. L-asparaginase was identified as the factor responsible for cell-cycle inhibition of fibroblasts and gastric cell lines. Its effect on cell-cycle was confirmed by inhibitors, a knockout strain and the action of recombinant L-asparaginase on cell lines. Interference with cell-cycle in vitro depended on cell genotype and was related to the expression levels of the concurrent enzyme asparagine synthetase. Bacterial subcellular distribution of L-asparaginase was also analysed along with its immunogenicity. H. pylori L-asparaginase is a novel antigen that functions as a cell-cycle inhibitor of fibroblasts and gastric cell lines. We give evidence supporting a role in the pathogenesis of H. pylori-related diseases and discuss its potential diagnostic application. PMID:21085483

  9. Subversion of Cell Cycle Regulatory Mechanisms by HIV.

    Science.gov (United States)

    Rice, Andrew P; Kimata, Jason T

    2015-06-10

    To establish a productive infection, HIV-1 must counteract cellular innate immune mechanisms and redirect cellular processes toward viral replication. Recent studies have discovered that HIV-1 and other primate immunodeficiency viruses subvert cell cycle regulatory mechanisms to achieve these ends. The viral Vpr and Vpx proteins target cell cycle controls to counter innate immunity. The cell-cycle-related protein Cyclin L2 is also utilized to counter innate immunity. The viral Tat protein utilizes Cyclin T1 to activate proviral transcription, and regulation of Cyclin T1 levels in CD4(+) T cells has important consequences for viral replication and latency. This review will summarize this emerging evidence that primate immunodeficiency viruses subvert cell cycle regulatory mechanisms to enhance replication. Copyright © 2015 Elsevier Inc. All rights reserved.

  10. 2-Aminopurine overrides multiple cell cycle checkpoints in BHK cells.

    OpenAIRE

    Andreassen, P R; Margolis, R L

    1992-01-01

    BHK cells blocked at any of several points in the cell cycle override their drug-induced arrest and proceed in the cycle when exposed concurrently to the protein kinase inhibitor 2-aminopurine (2-AP). For cells arrested at various points in interphase, 2-AP-induced cell cycle progression is made evident by arrival of the drug-treated cell population in mitosis. Cells that have escaped from mimosine G1 arrest, from hydroxyurea or aphidicolin S-phase arrest, or from VM-26-induced G2 arrest subs...

  11. A hybrid mammalian cell cycle model

    Directory of Open Access Journals (Sweden)

    Vincent Noël

    2013-08-01

    Full Text Available Hybrid modeling provides an effective solution to cope with multiple time scales dynamics in systems biology. Among the applications of this method, one of the most important is the cell cycle regulation. The machinery of the cell cycle, leading to cell division and proliferation, combines slow growth, spatio-temporal re-organisation of the cell, and rapid changes of regulatory proteins concentrations induced by post-translational modifications. The advancement through the cell cycle comprises a well defined sequence of stages, separated by checkpoint transitions. The combination of continuous and discrete changes justifies hybrid modelling approaches to cell cycle dynamics. We present a piecewise-smooth version of a mammalian cell cycle model, obtained by hybridization from a smooth biochemical model. The approximate hybridization scheme, leading to simplified reaction rates and binary event location functions, is based on learning from a training set of trajectories of the smooth model. We discuss several learning strategies for the parameters of the hybrid model.

  12. Differential expression of cell cycle and WNT pathway-related genes accounts for differences in the growth and differentiation potential of Wharton's jelly and bone marrow-derived mesenchymal stem cells.

    Science.gov (United States)

    Batsali, Aristea K; Pontikoglou, Charalampos; Koutroulakis, Dimitrios; Pavlaki, Konstantia I; Damianaki, Athina; Mavroudi, Irene; Alpantaki, Kalliopi; Kouvidi, Elisavet; Kontakis, George; Papadaki, Helen A

    2017-04-26

    In view of the current interest in exploring the clinical use of mesenchymal stem cells (MSCs) from different sources, we performed a side-by-side comparison of the biological properties of MSCs isolated from the Wharton's jelly (WJ), the most abundant MSC source in umbilical cord, with bone marrow (BM)-MSCs, the most extensively studied MSC population. MSCs were isolated and expanded from BM aspirates of hematologically healthy donors (n = 18) and from the WJ of full-term neonates (n = 18). We evaluated, in parallel experiments, the MSC immunophenotypic, survival and senescence characteristics as well as their proliferative potential and cell cycle distribution. We also assessed the expression of genes associated with the WNT- and cell cycle-signaling pathway and we performed karyotypic analysis through passages to evaluate the MSC genomic stability. The hematopoiesis-supporting capacity of MSCs from both sources was investigated by evaluating the clonogenic cells in the non-adherent fraction of MSC co-cultures with BM or umbilical cord blood-derived CD34 + cells and by measuring the hematopoietic cytokines levels in MSC culture supernatants. Finally, we evaluated the ability of MSCs to differentiate into adipocytes and osteocytes and the effect of the WNT-associated molecules WISP-1 and sFRP4 on the differentiation potential of WJ-MSCs. Both ex vivo-expanded MSC populations showed similar morphologic, immunophenotypic, survival and senescence characteristics and acquired genomic alterations at low frequency during passages. WJ-MSCs exhibited higher proliferative potential, possibly due to upregulation of genes that stimulate cell proliferation along with downregulation of genes related to cell cycle inhibition. WJ-MSCs displayed inferior lineage priming and differentiation capacity toward osteocytes and adipocytes, compared to BM-MSCs. This finding was associated with differential expression of molecules related to WNT signaling, including WISP1 and sFRP4

  13. Impact of the cell division cycle on gene circuits

    Science.gov (United States)

    Bierbaum, Veronika; Klumpp, Stefan

    2015-12-01

    In growing cells, protein synthesis and cell growth are typically not synchronous, and, thus, protein concentrations vary over the cell division cycle. We have developed a theoretical description of genetic regulatory systems in bacteria that explicitly considers the cell division cycle to investigate its impact on gene expression. We calculate the cell-to-cell variations arising from cells being at different stages in the division cycle for unregulated genes and for basic regulatory mechanisms. These variations contribute to the extrinsic noise observed in single-cell experiments, and are most significant for proteins with short lifetimes. Negative autoregulation buffers against variation of protein concentration over the division cycle, but the effect is found to be relatively weak. Stronger buffering is achieved by an increased protein lifetime. Positive autoregulation can strongly amplify such variation if the parameters are set to values that lead to resonance-like behaviour. For cooperative positive autoregulation, the concentration variation over the division cycle diminishes the parameter region of bistability and modulates the switching times between the two stable states. The same effects are seen for a two-gene mutual-repression toggle switch. By contrast, an oscillatory circuit, the repressilator, is only weakly affected by the division cycle.

  14. Fuel cell hybrid taxi life cycle analysis

    Energy Technology Data Exchange (ETDEWEB)

    Baptista, Patricia, E-mail: patricia.baptista@ist.utl.pt [IDMEC-Instituto Superior Tecnico, Universidade Tecnica de Lisboa, Av. Rovisco Pais, 1, 1049-001 Lisboa (Portugal); Ribau, Joao; Bravo, Joao; Silva, Carla [IDMEC-Instituto Superior Tecnico, Universidade Tecnica de Lisboa, Av. Rovisco Pais, 1, 1049-001 Lisboa (Portugal); Adcock, Paul; Kells, Ashley [Intelligent Energy, Charnwood Building, HolywellPark, Ashby Road, Loughborough, LE11 3GR (United Kingdom)

    2011-09-15

    A small fleet of classic London Taxis (Black cabs) equipped with hydrogen fuel cell power systems is being prepared for demonstration during the 2012 London Olympics. This paper presents a Life Cycle Analysis for these vehicles in terms of energy consumption and CO{sub 2} emissions, focusing on the impacts of alternative vehicle technologies for the Taxi, combining the fuel life cycle (Tank-to-Wheel and Well-to-Tank) and vehicle materials Cradle-to-Grave. An internal combustion engine diesel taxi was used as the reference vehicle for the currently available technology. This is compared to battery and fuel cell vehicle configurations. Accordingly, the following energy pathways are compared: diesel, electricity and hydrogen (derived from natural gas steam reforming). Full Life Cycle Analysis, using the PCO-CENEX drive cycle, (derived from actual London Taxi drive cycles) shows that the fuel cell powered vehicle configurations have lower energy consumption (4.34 MJ/km) and CO{sub 2} emissions (235 g/km) than both the ICE Diesel (9.54 MJ/km and 738 g/km) and the battery electric vehicle (5.81 MJ/km and 269 g/km). - Highlights: > A Life Cycle Analysis of alternative vehicle technologies for the London Taxi was performed. > The hydrogen powered vehicles have the lowest energy consumption and CO{sub 2} emissions results. > A hydrogen powered solution can be a sustainable alternative in a full life cycle framework.

  15. Fuel cell hybrid taxi life cycle analysis

    International Nuclear Information System (INIS)

    Baptista, Patricia; Ribau, Joao; Bravo, Joao; Silva, Carla; Adcock, Paul; Kells, Ashley

    2011-01-01

    A small fleet of classic London Taxis (Black cabs) equipped with hydrogen fuel cell power systems is being prepared for demonstration during the 2012 London Olympics. This paper presents a Life Cycle Analysis for these vehicles in terms of energy consumption and CO 2 emissions, focusing on the impacts of alternative vehicle technologies for the Taxi, combining the fuel life cycle (Tank-to-Wheel and Well-to-Tank) and vehicle materials Cradle-to-Grave. An internal combustion engine diesel taxi was used as the reference vehicle for the currently available technology. This is compared to battery and fuel cell vehicle configurations. Accordingly, the following energy pathways are compared: diesel, electricity and hydrogen (derived from natural gas steam reforming). Full Life Cycle Analysis, using the PCO-CENEX drive cycle, (derived from actual London Taxi drive cycles) shows that the fuel cell powered vehicle configurations have lower energy consumption (4.34 MJ/km) and CO 2 emissions (235 g/km) than both the ICE Diesel (9.54 MJ/km and 738 g/km) and the battery electric vehicle (5.81 MJ/km and 269 g/km). - Highlights: → A Life Cycle Analysis of alternative vehicle technologies for the London Taxi was performed. → The hydrogen powered vehicles have the lowest energy consumption and CO 2 emissions results. → A hydrogen powered solution can be a sustainable alternative in a full life cycle framework.

  16. A nuclear glutathione cycle within the cell cycle.

    Science.gov (United States)

    Diaz Vivancos, Pedro; Wolff, Tonja; Markovic, Jelena; Pallardó, Federico V; Foyer, Christine H

    2010-10-15

    The complex antioxidant network of plant and animal cells has the thiol tripeptide GSH at its centre to buffer ROS (reactive oxygen species) and facilitate cellular redox signalling which controls growth, development and defence. GSH is found in nearly every compartment of the cell, including the nucleus. Transport between the different intracellular compartments is pivotal to the regulation of cell proliferation. GSH co-localizes with nuclear DNA at the early stages of proliferation in plant and animal cells. Moreover, GSH recruitment and sequestration in the nucleus during the G1- and S-phases of the cell cycle has a profound impact on cellular redox homoeostasis and on gene expression. For example, the abundance of transcripts encoding stress and defence proteins is decreased when GSH is sequestered in the nucleus. The functions of GSHn (nuclear GSH) are considered in the present review in the context of whole-cell redox homoeostasis and signalling, as well as potential mechanisms for GSH transport into the nucleus. We also discuss the possible role of GSHn as a regulator of nuclear proteins such as histones and PARP [poly(ADP-ribose) polymerase] that control genetic and epigenetic events. In this way, a high level of GSH in the nucleus may not only have an immediate effect on gene expression patterns, but also contribute to how cells retain a memory of the cellular redox environment that is transferred through generations.

  17. Improved Gene Targeting through Cell Cycle Synchronization.

    Directory of Open Access Journals (Sweden)

    Vasiliki Tsakraklides

    Full Text Available Gene targeting is a challenge in organisms where non-homologous end-joining is the predominant form of recombination. We show that cell division cycle synchronization can be applied to significantly increase the rate of homologous recombination during transformation. Using hydroxyurea-mediated cell cycle arrest, we obtained improved gene targeting rates in Yarrowia lipolytica, Arxula adeninivorans, Saccharomyces cerevisiae, Kluyveromyces lactis and Pichia pastoris demonstrating the broad applicability of the method. Hydroxyurea treatment enriches for S-phase cells that are active in homologous recombination and enables previously unattainable genomic modifications.

  18. Flavonoids: from cell cycle regulation to biotechnology.

    Science.gov (United States)

    Woo, Ho-Hyung; Jeong, Byeong Ryong; Hawes, Martha C

    2005-03-01

    Flavonoids have been proposed to play diverse roles in plant growth and development, including defense, symbiosis, pollen development and male fertility, polar auxin transport, and protection against ultraviolet radiation. Recently, a new role in cell cycle regulation has emerged. Genetic alteration of glucuronide metabolism by altered expression of a Pisum sativum UDP-glucuronosyltransferase (PsUGT1) results in an altered cell cycle in pea, alfalfa, and Arabidopsis. In alfalfa, altered expression of PsUGT1 results in accumulation of a flavonoid-like compound that suppresses growth of cultured cells. The results are consistent with the hypothesis that PsUGT1 functions by controlling cellular levels of a factor controlling cell cycle (FCC).

  19. p27kip1-independent cell cycle regulation by MYC

    NARCIS (Netherlands)

    Berns, K.; Martins, C.; Dannenberg, J.-H.; Berns, A.J.M.; Riele, H. te; Bernards, R.A.

    2000-01-01

    MYC transcription factors are potent stimulators of cell proliferation. It has been suggested that the CDK-inhibitor p27kip1 is a critical G1 phase cell cycle target of c-MYC. We show here that mouse embryo fibroblasts deficient for both p27kip1 and the related p21cip1 are still responsive to

  20. Cell cycle in egg cell and its progression during zygotic development in rice.

    Science.gov (United States)

    Sukawa, Yumiko; Okamoto, Takashi

    2018-03-01

    Rice egg is arrested at G1 phase probably by OsKRP2. After fusion with sperm, karyogamy, OsWEE1-mediated parental DNA integrity in zygote nucleus, zygote progresses cell cycle to produce two-celled embryo. In angiosperms, female and male gametes exist in gametophytes after the complementation of meiosis and the progression of nuclear/cell division of the haploid cell. Within the embryo sac, the egg cell is specially differentiated for fertilization and subsequent embryogenesis, and cellular programs for embryonic development, such as restarting the cell cycle and de novo gene expression, are halted. There is only limited knowledge about how the cell cycle in egg cells restarts toward zygotic division, although the conversion of the cell cycle from a quiescent and arrested state to an active state is the most evident transition of cell status from egg cell to zygote. This is partly due to the difficulty in direct access and analysis of egg cells, zygotes and early embryos, which are deeply embedded in ovaries. In this study, precise relative DNA amounts in the nuclei of egg cells, developing zygotes and cells of early embryos were measured, and the cell cycle of a rice egg cell was estimated as the G1 phase with a 1C DNA level. In addition, increases in DNA content in zygote nuclei via karyogamy and DNA replication were also detectable according to progression of the cell cycle. In addition, expression profiles for cell cycle-related genes in egg cells and zygotes were also addressed, and it was suggested that OsKRP2 and OsWEE1 function in the inhibition of cell cycle progression in egg cells and in checkpoint of parental DNA integrity in zygote nucleus, respectively.

  1. Do lipids shape the eukaryotic cell cycle?

    Science.gov (United States)

    Furse, Samuel; Shearman, Gemma C

    2018-01-01

    Successful passage through the cell cycle presents a number of structural challenges to the cell. Inceptive studies carried out in the last five years have produced clear evidence of modulations in the lipid profile (sometimes referred to as the lipidome) of eukaryotes as a function of the cell cycle. This mounting body of evidence indicates that lipids play key roles in the structural transformations seen across the cycle. The accumulation of this evidence coincides with a revolution in our understanding of how lipid composition regulates a plethora of biological processes ranging from protein activity through to cellular signalling and membrane compartmentalisation. In this review, we discuss evidence from biological, chemical and physical studies of the lipid fraction across the cell cycle that demonstrate that lipids are well-developed cellular components at the heart of the biological machinery responsible for managing progress through the cell cycle. Furthermore, we discuss the mechanisms by which this careful control is exercised. Crown Copyright © 2017. Published by Elsevier B.V. All rights reserved.

  2. Choosing Cell Fate Through a Dynamic Cell Cycle.

    Science.gov (United States)

    Chen, Xinyue; Hartman, Amaleah; Guo, Shangqin

    2015-01-01

    A close relationship between proliferation and cell fate specification has been well documented in many developmental systems. In addition to the gradual cell fate changes accompanying normal development and tissue homeostasis, it is now commonly appreciated that cell fate could also undergo drastic changes, as illustrated by the induction of pluripotency from many differentiated somatic cell types during the process of Yamanaka reprogramming. Strikingly, the drastic cell fate change induced by Yamanaka factors (Oct4, Sox2, Klf4, and c-Myc) is preceded by extensive cell cycle acceleration. Prompted by our recent discovery that progression toward pluripotency from rare somatic cells could bypass the stochastic phase of reprogramming and that a key feature of these somatic cells is an ultrafast cell cycle (~8 h/cycle), we assess whether cell cycle dynamics could provide a general framework for controlling cell fate. Several potential mechanisms on how cell cycle dynamics may impact cell fate determination by regulating chromatin, key transcription factor concentration, or their interactions are discussed. Specific challenges and implications for studying and manipulating cell fate are considered.

  3. K+ channels and cell cycle progression in tumor cells

    Directory of Open Access Journals (Sweden)

    HALIMA eOUADID-AHIDOUCH

    2013-08-01

    Full Text Available K+ ions play a major role in many cellular processes. The deregulation of K+ signaling is associated with a variety of diseases such as hypertension, atherosclerosis, or diabetes. K+ ions are important for setting the membrane potential, the driving force for Ca2+ influx, and regulate volume of growing cells. Moreover, it is increasingly recognized that K+ channels control cell proliferation through a novel signaling mechanisms triggered and modulated independently of ion fluxes. In cancer, aberrant expression, regulation and/or sublocalization of K+ channels can alter the downstream signals that converge on the cell cycle machinery. Various K+ channels are involved in cell cycle progression and are needed only at particular stages of the cell cycle. Consistent with this idea, the expression of Eag1 and HERG channels fluctuate along the cell cycle. Despite of acquired knowledge, our understanding of K+ channels functioning in cancer cells requires further studies. These include identifying the molecular mechanisms controling the cell cycle machinery. By understanding how K+ channels regulate cell cycle progression in cancer cells, we will gain insights into how cancer cells subvert the need for K+ signal and its downstream targets to proliferate.

  4. Transcriptional control of the cell cycle.

    Science.gov (United States)

    Sánchez, I; Dynlacht, B D

    1996-06-01

    Although a significant amount of evidence has demonstrated that there are intimate connections between transcriptional controls and cell cycle regulation, the precise mechanisms underlying these connections remain largely obscure. A number of recent advances have helped to define how critical cell cycle regulators, such as the retinoblastoma family of tumor suppressor proteins and the cyclin-dependent kinases, might function on a biochemical level and how such mechanisms of action have been conserved not only in the regulation of transcription by all three RNA polymerases but also across species lines. In addition, the use of in vivo techniques has begun to explain how the activity of the E2F transcription factor family is tied to the cell cycle dependent expression of target genes.

  5. A low protein diet during pregnancy provokes a lasting shift of hepatic expression of genes related to cell cycle throughout ontogenesis in a porcine model

    Directory of Open Access Journals (Sweden)

    Oster Michael

    2012-03-01

    Full Text Available Abstract Background In rodent models and in humans the impact of gestational diets on the offspring's phenotype was shown experimentally and epidemiologically. Adverse environmental conditions during fetal development provoke an intrauterine adaptive response termed 'fetal programming', which may lead to both persistently biased responsiveness to extrinsic factors and permanent consequences for the organismal phenotype. This leads to the hypothesis that the offspring's transcriptome exhibits short-term and long-term changes, depending on the maternal diet. In order to contribute to a comprehensive inventory of genes and functional networks that are targets of nutritional programming initiated during fetal life, we applied whole-genome microarrays for expression profiling in a longitudinal experimental design covering prenatal, perinatal, juvenile, and adult ontogenetic stages in a porcine model. Pregnant sows were fed either a gestational low protein diet (LP, 6% CP or an adequate protein diet (AP, 12% CP. All offspring was nursed by foster sows receiving standard diets. After weaning, all offspring was fed standard diets ad libitum. Results Analyses of the hepatic gene expression of the offspring at prenatal (94 dies post conceptionem, dpc and postnatal stages (1, 28, 188 dies post natum, dpn included comparisons between dietary groups within stages as well as comparisons between ontogenetic stages within diets to separate diet-specific transcriptional changes and maturation processes. We observed differential expression of genes related to lipid metabolism (e.g. Fatty acid metabolism, Biosynthesis of steroids, Synthesis and degradation of ketone bodies, FA elongation in mitochondria, Bile acid synthesis and cell cycle regulation (e.g. Mitotic roles of PLK, G1/S checkpoint regulation, G2/M DNA damage checkpoint regulation. Notably, at stage 1 dpn no regulation of a distinct pathway was found in LP offspring. Conclusions The transcriptomic

  6. CGGBP1 regulates cell cycle in cancer cells

    Directory of Open Access Journals (Sweden)

    Uhrbom Lene

    2011-07-01

    Full Text Available Abstract Background CGGBP1 is a CGG-triplet repeat binding protein, which affects transcription from CGG-triplet-rich promoters such as the FMR1 gene and the ribosomal RNA gene clusters. Earlier, we reported some previously unknown functions of CGGBP1 in gene expression during heat shock stress response. Recently we had found CGGBP1 to be a cell cycle regulatory midbody protein required for normal cytokinetic abscission in normal human fibroblasts, which have all the cell cycle regulatory mechanisms intact. Results In this study we explored the role of CGGBP1 in the cell cycle in various cancer cell lines. CGGBP1 depletion by RNA interference in tumor-derived cells caused an increase in the cell population at G0/G1 phase and reduced the number of cells in the S phase. CGGBP1 depletion also increased the expression of cell cycle regulatory genes CDKN1A and GAS1, associated with reductions in histone H3 lysine 9 trimethylation in their promoters. By combining RNA interference and genetic mutations, we found that the role of CGGBP1 in cell cycle involves multiple mechanisms, as single deficiencies of CDKN1A, GAS1 as well as TP53, INK4A or ARF failed to rescue the G0/G1 arrest caused by CGGBP1 depletion. Conclusions Our results show that CGGBP1 expression is important for cell cycle progression through multiple parallel mechanisms including the regulation of CDKN1A and GAS1 levels.

  7. SUV2, which encodes an ATR-related cell cycle checkpoint and putative plant ATRIP, is required for aluminium-dependent root growth inhibition in Arabidopsis.

    Science.gov (United States)

    Sjogren, Caroline A; Larsen, Paul B

    2017-09-01

    A suppressor mutagenesis screen was conducted in order to identify second site mutations that could reverse the extreme hypersensitivity to aluminium (Al) seen for the Arabidopsis mutant, als3-1. From this screen, it was found that a loss-of-function mutation in the previously described SUV2 (SENSITIVE TO UV 2), which encodes a putative plant ATRIP homologue that is a component of the ATR-dependent cell checkpoint response, reversed the als3-1 phenotype. This included prevention of hallmarks associated with als3-1 including Al-dependent terminal differentiation of the root tip and transition to endoreduplication. From this analysis, SUV2 was determined to be required for halting cell cycle progression and triggering loss of the quiescent centre (QC) following exposure to Al. In conjunction with this, SUV2 was found to have a similar role as ATR, ALT2 and SOG1 in Al-dependent stoppage of root growth, all of which are required for promotion of expression of a suite of genes that likely are part of an Al-dependent DNA damage transcriptional response. This work argues that these Al response factors work together to detect Al-dependent damage and subsequently activate a DNA damage response pathway that halts the cell cycle and subsequently promotes QC differentiation and entrance into endocycling. © 2017 John Wiley & Sons Ltd.

  8. Inhibition of protein kinase C in PHA-activated PBMC treated with anti-HLA class I monoclonal antibody is associated to decreased proliferation and expression of cell cycle related genes.

    Science.gov (United States)

    Rita, S; Michele, R; Patrizia, O; Alessansdra, B; Sara, B; Enrico, G

    1994-01-01

    Treatment of PHA-activated PBMC with anti-HLA class I monoclonal antibody (mAb 01.65) shows: 1) depletion of particulate protein Kinase C (PKC) and partial reduction of cytosolic PKC after only 10 min.; 2) inhibition of tritiated thymidine (3H-Td) incorporation; 3) slowing down of cell cycle; 4) reduced expression of four cell cycle related genes. These findings suggest that the depletion of PKC is reflected on the cell cycle progression and expression of cell cycle related genes. We studied, in PHA-activated PBMC cultures, the effect of N-N-Staurosporine (StSp) acting as PKC inhibitor at nanomolar concentrations, alone and combined with mAb 01.65. StSp, inhibits the proliferative response of PHA stimulated PBMC in a competitive fashion with mAb 01.65. We report here that StSp alone and combined with mAb 01.65 affects also the expression of c-myc and cdc2 and the membrane expression of two proliferation markers: IL-2R (CD25) and TfR (CD71).

  9. Control points within the cell cycle

    International Nuclear Information System (INIS)

    Van't Hof, J.

    1984-01-01

    Evidence of the temporal order of chromosomal DNA replication argues favorably for the view that the cell cycle is controlled by genes acting in sequence whose time of expression is determined by mitosis and the amount of nuclear DNA (2C vs 4C) in the cell. Gl and G2 appear to be carbohydrate dependent in that cells starved of either carbohydrate of phosphate fail to make these transitions. Cells deprived of nitrate, however, fail only at Gl to S transition indicating that the controls that operate in G1 differ from those that operate in G2. 46 references, 5 figures

  10. Cell cycle and apoptosis genes in atherosclerosis

    NARCIS (Netherlands)

    Boesten, Lianne Simone Mirjam

    2006-01-01

    The work described in this thesis was aimed at identifying the role of cell cycle and apoptosis genes in atherosclerosis. Atherosclerosis is the primary cause of cardiovascular disease, a disorder occurring in the large and medium-sized arteries of the body. Although in the beginning 90s promising

  11. The sweet side of the cell cycle.

    Science.gov (United States)

    Tan, Ee Phie; Duncan, Francesca E; Slawson, Chad

    2017-04-15

    Cell division (mitosis) and gamete production (meiosis) are fundamental requirements for normal organismal development. The mammalian cell cycle is tightly regulated by different checkpoints ensuring complete and precise chromosomal segregation and duplication. In recent years, researchers have become increasingly interested in understanding how O -GlcNAc regulates the cell cycle. The O -GlcNAc post-translation modification is an O -glycosidic bond of a single β- N -acetylglucosamine sugar to serine/threonine residues of intracellular proteins. This modification is sensitive toward changes in nutrient levels in the cellular environment making O -GlcNAc a nutrient sensor capable of influencing cell growth and proliferation. Numerous studies have established that O-GlcNAcylation is essential in regulating mitosis and meiosis, while loss of O-GlcNAcylation is lethal in growing cells. Moreover, aberrant O-GlcNAcylation is linked with cancer and chromosomal segregation errors. In this review, we will discuss how O -GlcNAc controls different aspects of the cell cycle with a particular emphasis on mitosis and meiosis. © 2017 The Author(s); published by Portland Press Limited on behalf of the Biochemical Society.

  12. Analysis of cell cycle-related proteins in gastric intramucosal differentiated-type cancers based on mucin phenotypes: a novel hypothesis of early gastric carcinogenesis based on mucin phenotype

    Directory of Open Access Journals (Sweden)

    Matsushita Hiroo

    2010-06-01

    Full Text Available Abstract Background Abnormalities of cell cycle regulators are common features in human cancers, and several of these factors are associated with the early development of gastric cancers. However, recent studies have shown that gastric cancer tumorigenesis was characterized by mucin expression. Thus, expression patterns of cell cycle-related proteins were investigated in the early phase of differentiated-type gastric cancers to ascertain any mechanistic relationships with mucin phenotypes. Methods Immunostaining for Cyclins D1, A, E, and p21, p27, p53 and β-catenin was used to examine impairments of the cell cycle in 190 gastric intramucosal differentiated-type cancers. Mucin phenotypes were determined by the expressions of MUC5AC, MUC6, MUC2 and CD10. A Ki-67 positive rate (PR was also examined. Results Overexpressions of p53, cyclin D1 and cyclin A were significantly more frequent in a gastric phenotype than an intestinal phenotype. Cyclin A was overexpressed in a mixed phenotype compared with an intestinal phenotype, while p27 overexpression was more frequent in an intestinal phenotype than in a mixed phenotype. Reduction of p21 was a common feature of the gastric intramucosal differentiated-type cancers examined. Conclusions Our results suggest that the levels of some cell cycle regulators appear to be associated with mucin phenotypes of early gastric differentiated-type cancers.

  13. Cell cycle regulation and radiation-induced cell death

    International Nuclear Information System (INIS)

    Favaudon, V.

    2000-01-01

    Tight control of cell proliferation is mandatory to prevent cancer formation as well as to normal organ development and homeostasis. This occurs through checkpoints that operate in both time and space and are involved in the control of numerous pathways including DNA replication and transcription, cell cycle progression, signal transduction and differentiation. Moreover, evidence has accumulated to show that apoptosis is tightly connected with the regulation of cell cycle progression. In this paper we describe the main pathways that determine checkpoints in the cell cycle and apoptosis. It is also recalled that in solid tumors radiation-induced cell death occurs most frequently through non-apoptotic mechanisms involving oncosis, and mitotic or delayed cell death. (author)

  14. The cell cycle as a brake for β-cell regeneration from embryonic stem cells.

    Science.gov (United States)

    El-Badawy, Ahmed; El-Badri, Nagwa

    2016-01-13

    The generation of insulin-producing β cells from stem cells in vitro provides a promising source of cells for cell transplantation therapy in diabetes. However, insulin-producing cells generated from human stem cells show deficiency in many functional characteristics compared with pancreatic β cells. Recent reports have shown molecular ties between the cell cycle and the differentiation mechanism of embryonic stem (ES) cells, assuming that cell fate decisions are controlled by the cell cycle machinery. Both β cells and ES cells possess unique cell cycle machinery yet with significant contrasts. In this review, we compare the cell cycle control mechanisms in both ES cells and β cells, and highlight the fundamental differences between pluripotent cells of embryonic origin and differentiated β cells. Through critical analysis of the differences of the cell cycle between these two cell types, we propose that the cell cycle of ES cells may act as a brake for β-cell regeneration. Based on these differences, we discuss the potential of modulating the cell cycle of ES cells for the large-scale generation of functionally mature β cells in vitro. Further understanding of the factors that modulate the ES cell cycle will lead to new approaches to enhance the production of functional mature insulin-producing cells, and yield a reliable system to generate bona fide β cells in vitro.

  15. α-Mangostin Induces Apoptosis and Cell Cycle Arrest in Oral Squamous Cell Carcinoma Cell

    Directory of Open Access Journals (Sweden)

    Hyun-Ho Kwak

    2016-01-01

    Full Text Available Mangosteen has long been used as a traditional medicine and is known to have antibacterial, antioxidant, and anticancer effects. Although the effects of α-mangostin, a natural compound extracted from the pericarp of mangosteen, have been investigated in many studies, there is limited data on the effects of the compound in human oral squamous cell carcinoma (OSCC. In this study, α-mangostin was assessed as a potential anticancer agent against human OSCC cells. α-Mangostin inhibited cell proliferation and induced cell death in OSCC cells in a dose- and time-dependent manner with little to no effect on normal human PDLF cells. α-Mangostin treatment clearly showed apoptotic evidences such as nuclear fragmentation and accumulation of annexin V and PI-positive cells on OSCC cells. α-Mangostin treatment also caused the collapse of mitochondrial membrane potential and the translocation of cytochrome c from the mitochondria into the cytosol. The expressions of the mitochondria-related proteins were activated by α-mangostin. Treatment with α-mangostin also induced G1 phase arrest and downregulated cell cycle-related proteins (CDK/cyclin. Hence, α-mangostin specifically induces cell death and inhibits proliferation in OSCC cells via the intrinsic apoptosis pathway and cell cycle arrest at the G1 phase, suggesting that α-mangostin may be an effective agent for the treatment of OSCC.

  16. A combined gas cooled nuclear reactor and fuel cell cycle

    Science.gov (United States)

    Palmer, David J.

    Rising oil costs, global warming, national security concerns, economic concerns and escalating energy demands are forcing the engineering communities to explore methods to address these concerns. It is the intention of this thesis to offer a proposal for a novel design of a combined cycle, an advanced nuclear helium reactor/solid oxide fuel cell (SOFC) plant that will help to mitigate some of the above concerns. Moreover, the adoption of this proposal may help to reinvigorate the Nuclear Power industry while providing a practical method to foster the development of a hydrogen economy. Specifically, this thesis concentrates on the importance of the U.S. Nuclear Navy adopting this novel design for its nuclear electric vessels of the future with discussion on efficiency and thermodynamic performance characteristics related to the combined cycle. Thus, the goals and objectives are to develop an innovative combined cycle that provides a solution to the stated concerns and show that it provides superior performance. In order to show performance, it is necessary to develop a rigorous thermodynamic model and computer program to analyze the SOFC in relation with the overall cycle. A large increase in efficiency over the conventional pressurized water reactor cycle is realized. Both sides of the cycle achieve higher efficiencies at partial loads which is extremely important as most naval vessels operate at partial loads as well as the fact that traditional gas turbines operating alone have poor performance at reduced speeds. Furthermore, each side of the cycle provides important benefits to the other side. The high temperature exhaust from the overall exothermic reaction of the fuel cell provides heat for the reheater allowing for an overall increase in power on the nuclear side of the cycle. Likewise, the high temperature helium exiting the nuclear reactor provides a controllable method to stabilize the fuel cell at an optimal temperature band even during transients helping

  17. SAMHD1 controls cell cycle status, apoptosis and HIV-1 infection in monocytic THP-1 cells

    International Nuclear Information System (INIS)

    Bonifati, Serena; Daly, Michele B.; St Gelais, Corine; Kim, Sun Hee; Hollenbaugh, Joseph A.; Shepard, Caitlin; Kennedy, Edward M.; Kim, Dong-Hyun; Schinazi, Raymond F.; Kim, Baek; Wu, Li

    2016-01-01

    SAMHD1 limits HIV-1 infection in non-dividing myeloid cells by decreasing intracellular dNTP pools. HIV-1 restriction by SAMHD1 in these cells likely prevents activation of antiviral immune responses and modulates viral pathogenesis, thus highlighting a critical role of SAMHD1 in HIV-1 physiopathology. Here, we explored the function of SAMHD1 in regulating cell proliferation, cell cycle progression and apoptosis in monocytic THP-1 cells. Using the CRISPR/Cas9 technology, we generated THP-1 cells with stable SAMHD1 knockout. We found that silencing of SAMHD1 in cycling cells stimulates cell proliferation, redistributes cell cycle population in the G 1 /G 0 phase and reduces apoptosis. These alterations correlated with increased dNTP levels and more efficient HIV-1 infection in dividing SAMHD1 knockout cells relative to control. Our results suggest that SAMHD1, through its dNTPase activity, affects cell proliferation, cell cycle distribution and apoptosis, and emphasize a key role of SAMHD1 in the interplay between cell cycle regulation and HIV-1 infection.

  18. SAMHD1 controls cell cycle status, apoptosis and HIV-1 infection in monocytic THP-1 cells

    Energy Technology Data Exchange (ETDEWEB)

    Bonifati, Serena [Center for Retrovirus Research, Department of Veterinary Biosciences, The Ohio State University, Columbus, OH (United States); Daly, Michele B. [Center for Drug Discovery, Department of Pediatrics, School of Medicine, Emory University, Atlanta, GA (United States); St Gelais, Corine; Kim, Sun Hee [Center for Retrovirus Research, Department of Veterinary Biosciences, The Ohio State University, Columbus, OH (United States); Hollenbaugh, Joseph A.; Shepard, Caitlin [Center for Drug Discovery, Department of Pediatrics, School of Medicine, Emory University, Atlanta, GA (United States); Kennedy, Edward M. [Department of Molecular Genetics and Microbiology, Duke University, Durham, NC (United States); Kim, Dong-Hyun [Department of Pharmacy, School of Pharmacy, Kyung-Hee University, Seoul (Korea, Republic of); Schinazi, Raymond F. [Center for Drug Discovery, Department of Pediatrics, School of Medicine, Emory University, Atlanta, GA (United States); Kim, Baek, E-mail: baek.kim@emory.edu [Center for Drug Discovery, Department of Pediatrics, School of Medicine, Emory University, Atlanta, GA (United States); Department of Pharmacy, School of Pharmacy, Kyung-Hee University, Seoul (Korea, Republic of); Wu, Li, E-mail: wu.840@osu.edu [Center for Retrovirus Research, Department of Veterinary Biosciences, The Ohio State University, Columbus, OH (United States)

    2016-08-15

    SAMHD1 limits HIV-1 infection in non-dividing myeloid cells by decreasing intracellular dNTP pools. HIV-1 restriction by SAMHD1 in these cells likely prevents activation of antiviral immune responses and modulates viral pathogenesis, thus highlighting a critical role of SAMHD1 in HIV-1 physiopathology. Here, we explored the function of SAMHD1 in regulating cell proliferation, cell cycle progression and apoptosis in monocytic THP-1 cells. Using the CRISPR/Cas9 technology, we generated THP-1 cells with stable SAMHD1 knockout. We found that silencing of SAMHD1 in cycling cells stimulates cell proliferation, redistributes cell cycle population in the G{sub 1}/G{sub 0} phase and reduces apoptosis. These alterations correlated with increased dNTP levels and more efficient HIV-1 infection in dividing SAMHD1 knockout cells relative to control. Our results suggest that SAMHD1, through its dNTPase activity, affects cell proliferation, cell cycle distribution and apoptosis, and emphasize a key role of SAMHD1 in the interplay between cell cycle regulation and HIV-1 infection.

  19. Short-Stalked Prosthecomicrobium hirschii Cells Have a Caulobacter-Like Cell Cycle.

    Science.gov (United States)

    Williams, Michelle; Hoffman, Michelle D; Daniel, Jeremy J; Madren, Seth M; Dhroso, Andi; Korkin, Dmitry; Givan, Scott A; Jacobson, Stephen C; Brown, Pamela J B

    2016-02-01

    The dimorphic alphaproteobacterium Prosthecomicrobium hirschii has both short-stalked and long-stalked morphotypes. Notably, these morphologies do not arise from transitions in a cell cycle. Instead, the maternal cell morphology is typically reproduced in daughter cells, which results in microcolonies of a single cell type. In this work, we further characterized the short-stalked cells and found that these cells have a Caulobacter-like life cycle in which cell division leads to the generation of two morphologically distinct daughter cells. Using a microfluidic device and total internal reflection fluorescence (TIRF) microscopy, we observed that motile short-stalked cells attach to a surface by means of a polar adhesin. Cells attached at their poles elongate and ultimately release motile daughter cells. Robust biofilm growth occurs in the microfluidic device, enabling the collection of synchronous motile cells and downstream analysis of cell growth and attachment. Analysis of a draft P. hirschii genome sequence indicates the presence of CtrA-dependent cell cycle regulation. This characterization of P. hirschii will enable future studies on the mechanisms underlying complex morphologies and polymorphic cell cycles. Bacterial cell shape plays a critical role in regulating important behaviors, such as attachment to surfaces, motility, predation, and cellular differentiation; however, most studies on these behaviors focus on bacteria with relatively simple morphologies, such as rods and spheres. Notably, complex morphologies abound throughout the bacteria, with striking examples, such as P. hirschii, found within the stalked Alphaproteobacteria. P. hirschii is an outstanding candidate for studies of complex morphology generation and polymorphic cell cycles. Here, the cell cycle and genome of P. hirschii are characterized. This work sets the stage for future studies of the impact of complex cell shapes on bacterial behaviors. Copyright © 2016, American Society for

  20. Identification of new ovulation-related genes in humans by comparing the transcriptome of granulosa cells before and after ovulation triggering in the same controlled ovarian stimulation cycle

    DEFF Research Database (Denmark)

    Wissing, M L; Kristensen, S G; Andersen, C Y

    2014-01-01

    of a mature oocyte and remodeling into a corpus luteum. A wide range of mediators of final follicle maturation has been identified in rodents, non-human primates and cows. STUDY DESIGN, SIZE, DURATION: Prospective cohort study including 24 women undergoing ovarian stimulation with the long gonadotrophin....... In silico analysis for top upstream regulators of the ovulatory trigger suggested--besides LH--TNF, IGF1, PGR, AR, EGR1 (early growth response 1), ERK1/2 (extracellular signal regulated kinase 1/2) and CDKN1A (cyclin-dependent kinase inhibitor 1A) as potential mediators of the LH/hCG response. LIMITATIONS......, REASONS FOR CAUTION: The present dataset was generated from women under hormonal stimulation. However, comparison with a macaque natural cycle whole follicle ovulation dataset revealed major overlap, supporting the idea that the ovulation-related genes found in this study are relevant in the human natural...

  1. MicroRNA-Related DNA Repair/Cell-Cycle Genes Independently Associated With Relapse After Radiation Therapy for Early Breast Cancer

    Energy Technology Data Exchange (ETDEWEB)

    Gee, Harriet E., E-mail: harriet.gee@sydney.edu.au [The Kinghorn Cancer Centre & Cancer Research Division, Garvan Institute of Medical Research, Darlinghurst, NSW (Australia); The Chris O' Brien Lifehouse, Missenden Road, Camperdown, NSW (Australia); Central Clinical School, Sydney Medical School, University of Sydney, NSW (Australia); Buffa, Francesca M.; Harris, Adrian L. [Department of Medical Oncology, The University of Oxford, Oxford (United Kingdom); Toohey, Joanne M.; Carroll, Susan L. [The Chris O' Brien Lifehouse, Missenden Road, Camperdown, NSW (Australia); Cooper, Caroline L. [Central Clinical School, Sydney Medical School, University of Sydney, NSW (Australia); Department of Tissue Pathology and Diagnostic Oncology, Royal Prince Alfred Hospital, Camperdown, NSW (Australia); Beith, Jane [The Chris O' Brien Lifehouse, Missenden Road, Camperdown, NSW (Australia); McNeil, Catriona [The Kinghorn Cancer Centre & Cancer Research Division, Garvan Institute of Medical Research, Darlinghurst, NSW (Australia); The Chris O' Brien Lifehouse, Missenden Road, Camperdown, NSW (Australia); Carmalt, Hugh; Mak, Cindy; Warrier, Sanjay [The Chris O' Brien Lifehouse, Missenden Road, Camperdown, NSW (Australia); Holliday, Anne [The Kinghorn Cancer Centre & Cancer Research Division, Garvan Institute of Medical Research, Darlinghurst, NSW (Australia); Selinger, Christina; Beckers, Rhiannon [Department of Tissue Pathology and Diagnostic Oncology, Royal Prince Alfred Hospital, Camperdown, NSW (Australia); Kennedy, Catherine [Central Clinical School, Sydney Medical School, University of Sydney, NSW (Australia); Graham, Peter [Department of Radiation Oncology, Cancer Care Centre, St. George Hospital, Kogarah, NSW (Australia); Swarbrick, Alexander [The Kinghorn Cancer Centre & Cancer Research Division, Garvan Institute of Medical Research, Darlinghurst, NSW (Australia); St Vincent' s Clinical School, Faculty of Medicine, University of NSW, Kensington, NSW (Australia); and others

    2015-12-01

    Purpose: Local recurrence and distant failure after adjuvant radiation therapy for breast cancer remain significant clinical problems, incompletely predicted by conventional clinicopathologic markers. We had previously identified microRNA-139-5p and microRNA-1274a as key regulators of breast cancer radiation response in vitro. The purpose of this study was to investigate standard clinicopathologic markers of local recurrence in a contemporary series and to establish whether putative target genes of microRNAs involved in DNA repair and cell cycle control could better predict radiation therapy response in vivo. Methods and Materials: With institutional ethics board approval, local recurrence was measured in a contemporary, prospectively collected series of 458 patients treated with radiation therapy after breast-conserving surgery. Additionally, independent publicly available mRNA/microRNA microarray expression datasets totaling >1000 early-stage breast cancer patients, treated with adjuvant radiation therapy, with >10 years of follow-up, were analyzed. The expression of putative microRNA target biomarkers—TOP2A, POLQ, RAD54L, SKP2, PLK2, and RAG1—were correlated with standard clinicopathologic variables using 2-sided nonparametric tests, and to local/distant relapse and survival using Kaplan-Meier and Cox regression analysis. Results: We found a low rate of isolated local recurrence (1.95%) in our modern series, and that few clinicopathologic variables (such as lymphovascular invasion) were significantly predictive. In multiple independent datasets (n>1000), however, high expression of RAD54L, TOP2A, POLQ, and SKP2 significantly correlated with local recurrence, survival, or both in univariate and multivariate analyses (P<.001). Low RAG1 expression significantly correlated with local recurrence (multivariate, P=.008). Additionally, RAD54L, SKP2, and PLK2 may be predictive, being prognostic in radiation therapy–treated patients but not in untreated matched

  2. Exosomes Secreted by Toxoplasma gondii-Infected L6 Cells: Their Effects on Host Cell Proliferation and Cell Cycle Changes.

    Science.gov (United States)

    Kim, Min Jae; Jung, Bong-Kwang; Cho, Jaeeun; Song, Hyemi; Pyo, Kyung-Ho; Lee, Ji Min; Kim, Min-Kyung; Chai, Jong-Yil

    2016-04-01

    Toxoplasma gondii infection induces alteration of the host cell cycle and cell proliferation. These changes are not only seen in directly invaded host cells but also in neighboring cells. We tried to identify whether this alteration can be mediated by exosomes secreted by T. gondii-infected host cells. L6 cells, a rat myoblast cell line, and RH strain of T. gondii were selected for this study. L6 cells were infected with or without T. gondii to isolate exosomes. The cellular growth patterns were identified by cell counting with trypan blue under confocal microscopy, and cell cycle changes were investigated by flow cytometry. L6 cells infected with T. gondii showed decreased proliferation compared to uninfected L6 cells and revealed a tendency to stay at S or G2/M cell phase. The treatment of exosomes isolated from T. gondii-infected cells showed attenuation of cell proliferation and slight enhancement of S phase in L6 cells. The cell cycle alteration was not as obvious as reduction of the cell proliferation by the exosome treatment. These changes were transient and disappeared at 48 hr after the exosome treatment. Microarray analysis and web-based tools indicated that various exosomal miRNAs were crucial for the regulation of target genes related to cell proliferation. Collectively, our study demonstrated that the exosomes originating from T. gondii could change the host cell proliferation and alter the host cell cycle.

  3. Cell reprogramming modelled as transitions in a hierarchy of cell cycles

    Science.gov (United States)

    Hannam, Ryan; Annibale, Alessia; Kühn, Reimer

    2017-10-01

    We construct a model of cell reprogramming (the conversion of fully differentiated cells to a state of pluripotency, known as induced pluripotent stem cells, or iPSCs) which builds on key elements of cell biology viz. cell cycles and cell lineages. Although reprogramming has been demonstrated experimentally, much of the underlying processes governing cell fate decisions remain unknown. This work aims to bridge this gap by modelling cell types as a set of hierarchically related dynamical attractors representing cell cycles. Stages of the cell cycle are characterised by the configuration of gene expression levels, and reprogramming corresponds to triggering transitions between such configurations. Two mechanisms were found for reprogramming in a two level hierarchy: cycle specific perturbations and a noise induced switching. The former corresponds to a directed perturbation that induces a transition into a cycle-state of a different cell type in the potency hierarchy (mainly a stem cell) whilst the latter is a priori undirected and could be induced, e.g. by a (stochastic) change in the cellular environment. These reprogramming protocols were found to be effective in large regimes of the parameter space and make specific predictions concerning reprogramming dynamics which are broadly in line with experimental findings.

  4. Regulatory mechanism of radiation-induced cancer cell death by the change of cell cycle

    Energy Technology Data Exchange (ETDEWEB)

    Jeong, Soo Jin; Jeong, Min Ho; Jang, Ji Yeon [College of Medicine, Donga Univ., Pusan (Korea, Republic of)

    2003-09-01

    In our previous study, we have shown the main cell death pattern induced by irradiation or protein tyrosine kinase (PTK) inhibitors in K562 human myelogenous leukemic cell line. Death of the cells treated with irradiation alone was characterized by mitotic catastrophe and typical radiation-induced apoptosis was accelerated by herbimycin A (HMA). Both types of cell death were inhibited by genistein. In this study, we investigated the effects of HMA and genistein on cell cycle regulation and its correlation with the alterations of radiation-induced cell death. K562 cells in exponential growth phase were used for this study. The cells were irradiated with 10 Gy using 6 MeV Linac (200-300 cGy/min). Immediately after irradiation, cells were treated with 250 nM of HMA or 25{mu}M of genistein. The distributions of cell cycle, the expressions of cell cycle-related protein, the activities of cyclin-dependent kinase, and the yield of senescence and differentiation were analyzed. X-irradiated cells were arrested in the G2 phase of the cell cycle but unlike the p53-positive cells, they were not able to sustain the cell cycle arrest. An accumulation of cells in G2 phase of first cell-cycle post-treatment and an increase of cyclin B1 were correlated with spontaneous, premature, chromosome condensation and mitotic catastrophe. HMA induced rapid G2 checkpoint abrogation and concomitant p53-independent G1 accumulation HMA-induced cell cycle modifications correlated with the increase of cdc2 kinase activity, the decrease of the expressions of cyclins E and A and of CDK2 kinase activity, and the enhancement of radiation-induced apoptosis. Genistein maintained cells that were arrested in the G2-phase, decreased the expressions of cyclin B1 and cdc25C and cdc2 kinase activity, increased the expression of p16, and sustained senescence and megakaryocytic differentiation. The effects of HMA and genistein on the radiation-induced cell death of K562 cells were closely related to the cell

  5. Pertanggungjawaban Sosial Universitas: Implementasi Model Cycle Relations

    Directory of Open Access Journals (Sweden)

    Lina Sinatra Wijaya

    2016-10-01

    Full Text Available The competition among Higher Education is getting tougher. They need to do their best in order to maintain their existence and getting more students coming to their institutions. One way to achieve that goal is through carrying out Corporate Social Responsibility (CSR programs or University Social Responsibility (USR for university. This study tries to investigate the implementation of ‘Cycle Relations’ model in CSR to increase the intake of Higher Education. This study involved seven Higher Educations and nineteen High schools in Central Java. In collecting the data, it used a depth-interview method with all the related parties in this study. The result showed that most of the Higher Education institutions have implemented Corporate Social Responsibility program in various ways. Their target audience included the high schools, society, and parents.  From the model implementation, it showed that the CSR program did have an impact towards the intake in their institution. However, one important thing to consider is that the role of the teachers at schools was quite significant in influencing the students to choose which university to go.  This reflects that although the Higher Education institution have planned and carried out CSR programs according to what the target audiences’ need, it does not guarantee that it will have direct impact towards their intake because the influence of teacher is quite significant. It may have a bigger impact in long term as the target audiences know the quality and contribution of the Higher Education institutions.

  6. Alteration of cell cycle progression by Sindbis virus infection

    Energy Technology Data Exchange (ETDEWEB)

    Yi, Ruirong; Saito, Kengo [Department of Molecular Virology, Graduate School of Medicine, Chiba University Graduate School of Medicine, 1-8-1 Inohana, Chiba 260-8670 (Japan); Isegawa, Naohisa [Laboratory Animal Center, Graduate School of Medicine, Chiba University Graduate School of Medicine, 1-8-1 Inohana, Chiba 260-8670 (Japan); Shirasawa, Hiroshi, E-mail: sirasawa@faculty.chiba-u.jp [Department of Molecular Virology, Graduate School of Medicine, Chiba University Graduate School of Medicine, 1-8-1 Inohana, Chiba 260-8670 (Japan)

    2015-07-10

    We examined the impact of Sindbis virus (SINV) infection on cell cycle progression in a cancer cell line, HeLa, and a non-cancerous cell line, Vero. Cell cycle analyses showed that SINV infection is able to alter the cell cycle progression in both HeLa and Vero cells, but differently, especially during the early stage of infection. SINV infection affected the expression of several cell cycle regulators (CDK4, CDK6, cyclin E, p21, cyclin A and cyclin B) in HeLa cells and caused HeLa cells to accumulate in S phase during the early stage of infection. Monitoring SINV replication in HeLa and Vero cells expressing cell cycle indicators revealed that SINV which infected HeLa cells during G{sub 1} phase preferred to proliferate during S/G{sub 2} phase, and the average time interval for viral replication was significantly shorter in both HeLa and Vero cells infected during G{sub 1} phase than in cells infected during S/G{sub 2} phase. - Highlights: • SINV infection was able to alter the cell cycle progression of infected cancer cells. • SINV infection can affect the expression of cell cycle regulators. • SINV infection exhibited a preference for the timing of viral replication among the cell cycle phases.

  7. Mitochondrial regulation of cell cycle progression through SLC25A43

    Energy Technology Data Exchange (ETDEWEB)

    Gabrielson, Marike; Reizer, Edwin [School of Health and Medical Sciences, Faculty of Medicine and Health, Örebro University, SE 70182 Örebro (Sweden); Stål, Olle [Department of Clinical and Experimental Medicine, Linköping University, SE 58185 Linköping (Sweden); Department of Oncology, Linköping University, SE 58185 Linköping (Sweden); Tina, Elisabet, E-mail: elisabet.tina@regionorebrolan.se [Department of Clinical Research Laboratory, Faculty of Medicine and Health, Örebro University, SE 70182 Örebro (Sweden)

    2016-01-22

    An increasing body of evidence is pointing towards mitochondrial regulation of the cell cycle. In a previous study of HER2-positive tumours we could demonstrate a common loss in the gene encoding for the mitochondrial transporter SLC25A43 and also a significant relation between SLC25A43 protein expression and S-phase fraction. Here, we investigated the consequence of suppressed SLC25A43 expression on cell cycle progression and proliferation in breast epithelial cells. In the present study, we suppressed SLC25A43 using siRNA in immortalised non-cancerous breast epithelial MCF10A cells and HER2-positive breast cancer cells BT-474. Viability, apoptosis, cell proliferation rate, cell cycle phase distribution, and nuclear Ki-67 and p21, were assessed by flow cytometry. Cell cycle related gene expressions were analysed using real-time PCR. We found that SLC25A43 knockdown in MCF10A cells significantly inhibited cell cycle progression during G{sub 1}-to-S transition, thus significantly reducing the proliferation rate and fraction of Ki-67 positive MCF10A cells. In contrast, suppressed SLC25A43 expression in BT-474 cells resulted in a significantly increased proliferation rate together with an enhanced G{sub 1}-to-S transition. This was reflected by an increased fraction of Ki-67 positive cells and reduced level of nuclear p21. In line with our previous results, we show a role for SLC25A43 as a regulator of cell cycle progression and proliferation through a putative mitochondrial checkpoint. These novel data further strengthen the connection between mitochondrial function and the cell cycle, both in non-malignant and in cancer cells. - Highlights: • Proposed cell cycle regulation through the mitochondrial transporter SLC25A43. • SLC25A43 alters cell proliferation rate and cell cycle progression. • Suppressed SLC25A43 influences transcription of cell cycle regulatory genes.

  8. Salidroside induces cell-cycle arrest and apoptosis in human breast cancer cells

    International Nuclear Information System (INIS)

    Hu, Xiaolan; Zhang, Xianqi; Qiu, Shuifeng; Yu, Daihua; Lin, Shuxin

    2010-01-01

    Research highlights: → Salidroside inhibits the growth of human breast cancer cells. → Salidroside induces cell-cycle arrest of human breast cancer cells. → Salidroside induces apoptosis of human breast cancer cell lines. -- Abstract: Recently, salidroside (p-hydroxyphenethyl-β-D-glucoside) has been identified as one of the most potent compounds isolated from plants of the Rhodiola genus used widely in traditional Chinese medicine, but pharmacokinetic data on the compound are unavailable. We were the first to report the cytotoxic effects of salidroside on cancer cell lines derived from different tissues, and we found that human breast cancer MDA-MB-231 cells (estrogen receptor negative) were sensitive to the inhibitory action of low-concentration salidroside. To further investigate the cytotoxic effects of salidroside on breast cancer cells and reveal possible ER-related differences in response to salidroside, we used MDA-MB-231 cells and MCF-7 cells (estrogen receptor-positive) as models to study possible molecular mechanisms; we evaluated the effects of salidroside on cell growth characteristics, such as proliferation, cell cycle duration, and apoptosis, and on the expression of apoptosis-related molecules. Our results demonstrated for the first time that salidroside induces cell-cycle arrest and apoptosis in human breast cancer cells and may be a promising candidate for breast cancer treatment.

  9. Salidroside induces cell-cycle arrest and apoptosis in human breast cancer cells

    Energy Technology Data Exchange (ETDEWEB)

    Hu, Xiaolan, E-mail: huxiaolan1998@yahoo.com.cn [Department of Pathology and Pathophysiology, Zhejiang University School of Medicine, Hangzhou (China); Zhang, Xianqi [The 2nd Affiliated Hospital of Zhejiang University School of Medicine, Hangzhou (China); Qiu, Shuifeng [Department of Pathology and Pathophysiology, Zhejiang University School of Medicine, Hangzhou (China); Yu, Daihua; Lin, Shuxin [Fourth Military Medical University, Xi' an (China)

    2010-07-16

    Research highlights: {yields} Salidroside inhibits the growth of human breast cancer cells. {yields} Salidroside induces cell-cycle arrest of human breast cancer cells. {yields} Salidroside induces apoptosis of human breast cancer cell lines. -- Abstract: Recently, salidroside (p-hydroxyphenethyl-{beta}-D-glucoside) has been identified as one of the most potent compounds isolated from plants of the Rhodiola genus used widely in traditional Chinese medicine, but pharmacokinetic data on the compound are unavailable. We were the first to report the cytotoxic effects of salidroside on cancer cell lines derived from different tissues, and we found that human breast cancer MDA-MB-231 cells (estrogen receptor negative) were sensitive to the inhibitory action of low-concentration salidroside. To further investigate the cytotoxic effects of salidroside on breast cancer cells and reveal possible ER-related differences in response to salidroside, we used MDA-MB-231 cells and MCF-7 cells (estrogen receptor-positive) as models to study possible molecular mechanisms; we evaluated the effects of salidroside on cell growth characteristics, such as proliferation, cell cycle duration, and apoptosis, and on the expression of apoptosis-related molecules. Our results demonstrated for the first time that salidroside induces cell-cycle arrest and apoptosis in human breast cancer cells and may be a promising candidate for breast cancer treatment.

  10. P27 in cell cycle control and cancer

    DEFF Research Database (Denmark)

    Møller, Michael Boe

    2000-01-01

    In order to survive, cells need tight control of cell cycle progression. The control mechanisms are often lost in human cancer cells. The cell cycle is driven forward by cyclin-dependent kinases (CDKs). The CDK inhibitors (CKIs) are important regulators of the CDKs. As the name implies, CKIs were...

  11. Analysis of Cell Cycle Switches in Drosophila Oogenesis.

    Science.gov (United States)

    Jia, Dongyu; Huang, Yi-Chun; Deng, Wu-Min

    2015-01-01

    The study of Drosophila oogenesis provides invaluable information about signaling pathway regulation and cell cycle programming. During Drosophila oogenesis, a string of egg chambers in each ovariole progressively develops toward maturity. Egg chamber development consists of 14 stages. From stage 1 to stage 6 (mitotic cycle), main-body follicle cells undergo mitotic divisions. From stage 7 to stage 10a (endocycle), follicle cells cease mitosis but continue three rounds of endoreduplication. From stage 10b to stage 13 (gene amplification), instead of whole genome duplication, follicle cells selectively amplify specific genomic regions, mostly for chorion production. So far, Drosophila oogenesis is one of the most well studied model systems used to understand cell cycle switches, which furthers our knowledge about cell cycle control machinery and sheds new light on potential cancer treatments. Here, we give a brief summary of cell cycle switches, the associated signaling pathways and factors, and the detailed experimental procedures used to study the cell cycle switches.

  12. KOH concentration effect on cycle life of nickel-hydrogen cells. III - Cycle life test

    Science.gov (United States)

    Lim, H. S.; Verzwyvelt, S. A.

    1988-01-01

    A cycle life test of Ni/H2 cells containing electrolytes of various KOH concentrations and a sintered type nickel electrode was carried out at 23 C using a 45 min accelerated low earth orbit (LEO) cycle regime at 80 percent depth of discharge. One of three cells containing 26 percent KOH has achieved over 28,000 cycles, and the other two 19,000 cycles, without a sign of failure. Two other cells containing 31 percent KOH electrolyte, which is the concentration presently used in aerospace cells, failed after 2,979 and 3,620 cycles. This result indicates that the cycle life of the present type of Ni/H2 cells may be extended by a factor of 5 to 10 simply by lowering the KOH concentration. Long cycle life of a Ni/H2 battery at high depth-of-discharge operation is desired, particularly for an LEO spacecraft application. Typically, battery life of about 30,000 cycles is required for a five year mission in an LEO. Such a cycle life with presently available cells can be assured only at a very low depth-of-discharge operation. Results of testing already show that the cycle life of an Ni/H2 cell is tremendously improved by simply using an electrolyte of low KOH concentration.

  13. Chloroplast Dysfunction Causes Multiple Defects in Cell Cycle Progression in the Arabidopsis crumpled leaf Mutant

    KAUST Repository

    Hudik, Elodie

    2014-07-18

    The majority of research on cell cycle regulation is focused on the nuclear events that govern the replication and segregation of the genome between the two daughter cells. However, eukaryotic cells contain several compartmentalized organelles with specialized functions, and coordination among these organelles is required for proper cell cycle progression, as evidenced by the isolation of several mutants in which both organelle function and overall plant development were affected. To investigate how chloroplast dysfunction affects the cell cycle, we analyzed the crumpled leaf (crl) mutant of Arabidopsis (Arabidopsis thaliana), which is deficient for a chloroplastic protein and displays particularly severe developmental defects. In the crl mutant, we reveal that cell cycle regulation is altered drastically and that meristematic cells prematurely enter differentiation, leading to reduced plant stature and early endoreduplication in the leaves. This response is due to the repression of several key cell cycle regulators as well as constitutive activation of stress-response genes, among them the cell cycle inhibitor SIAMESE-RELATED5. One unique feature of the crl mutant is that it produces aplastidic cells in several organs, including the root tip. By investigating the consequence of the absence of plastids on cell cycle progression, we showed that nuclear DNA replication occurs in aplastidic cells in the root tip, which opens future research prospects regarding the dialogue between plastids and the nucleus during cell cycle regulation in higher plants.

  14. Cell cycle checkpoints: reversible when possible, irreversible when needed

    NARCIS (Netherlands)

    Krenning, L.

    2015-01-01

    Cell cycle checkpoints are reversible in nature, and can prevent progression into the next cell cycle phase if needed. In the case of DNA damage, cells can prevent progression from G1 into S phase, and from G2 into mitosis in the presence of DNA double strand breaks. Following DNA repair, these

  15. Eukaryotic checkpoints are absent in the cell division cycle of ...

    Indian Academy of Sciences (India)

    Unknown

    are known to control the cell cycle of most eukaryotes, these genes may be structurally altered and their equiva- lent function yet to be ... points controlling the cell division of these organisms? Is the cell division cycle of these organisms ..... mitotic-phase inhibitor and may become a useful tool for studies on the relationship ...

  16. Indirect-fired gas turbine dual fuel cell power cycle

    Science.gov (United States)

    Micheli, Paul L.; Williams, Mark C.; Sudhoff, Frederick A.

    1996-01-01

    A fuel cell and gas turbine combined cycle system which includes dual fuel cell cycles combined with a gas turbine cycle wherein a solid oxide fuel cell cycle operated at a pressure of between 6 to 15 atms tops the turbine cycle and is used to produce CO.sub.2 for a molten carbonate fuel cell cycle which bottoms the turbine and is operated at essentially atmospheric pressure. A high pressure combustor is used to combust the excess fuel from the topping fuel cell cycle to further heat the pressurized gas driving the turbine. A low pressure combustor is used to combust the excess fuel from the bottoming fuel cell to reheat the gas stream passing out of the turbine which is used to preheat the pressurized air stream entering the topping fuel cell before passing into the bottoming fuel cell cathode. The CO.sub.2 generated in the solid oxide fuel cell cycle cascades through the system to the molten carbonate fuel cell cycle cathode.

  17. Mitochondrial dynamics and the cell cycle

    Directory of Open Access Journals (Sweden)

    Penny M.A. Kianian

    2014-05-01

    Full Text Available Nuclear-mitochondrial (NM communication impacts many aspects of plant development including vigor, sterility and viability. Dynamic changes in mitochondrial number, shape, size, and cellular location takes place during the cell cycle possibly impacting the process itself and leading to distribution of this organelle into daughter cells. The genes that underlie these changes are beginning to be identified in model plants such as Arabidopsis. In animals disruption of the drp1 gene, a homolog to the plant drp3A and drp3B, delays mitochondrial division. This mutation results in increased aneuploidy due to chromosome mis-segregation. It remains to be discovered if a similar outcome is observed in plants. Alloplasmic lines provide an opportunity to understand the communication between the cytoplasmic organelles and the nucleus. Examples of studies in these lines, especially from the extensive collection in wheat, point to the role of mitochondria in chromosome movement, pollen fertility and other aspects of development. Genes involved in NM interaction also are believed to play a critical role in evolution of species and interspecific cross incompatibilities.

  18. Cell cycle control by the thyroid hormone in neuroblastoma cells

    International Nuclear Information System (INIS)

    Garcia-Silva, Susana; Perez-Juste, German; Aranda, Ana

    2002-01-01

    The thyroid hormone (T3) blocks proliferation and induces differentiation of neuroblastoma N2a-β cells that overexpress the β1 isoform of the T3 receptor. An element in the region responsible for premature termination of transcription mediates a rapid repression of c-myc gene expression by T3. The hormone also causes a decrease of cyclin D1 gene transcription, and is able to antagonize the activation of the cyclin D1 promoter by Ras. In addition, a strong and sustained increase of the levels of the cyclin kinase inhibitor (CKI) p27 Kip1 are found in T3-treated cells. The increased levels of p27 Kip1 lead to a marked inhibition of the kinase activity of the cyclin-CDK2 complexes. As a consequence of these changes, retinoblastoma proteins are hypophosphorylated in T3-treated N2a-β cells, and progression through the restriction point in the cell cycle is blocked

  19. Cell cycle controls: potential targets for chemical carcinogens?

    OpenAIRE

    Afshari, C A; Barrett, J C

    1993-01-01

    The progression of the cell cycle is controlled by the action of both positive and negative growth regulators. The key players in this activity include a family of cyclins and cyclin-dependent kinases, which are themselves regulated by other kinases and phosphatases. Maintenance of balanced cell cycle controls may be directly linked to genomic stability. Loss of the check-points involved in cell cycle control may result in unrepaired DNA damage during DNA synthesis or mitosis leading to genet...

  20. Immunohistochemical study of the expression of cell cycle regulating proteins at different stages of bladder cancer

    DEFF Research Database (Denmark)

    Primdahl, Hanne; von der Maase, Hans; Sørensen, Flemming Brandt

    2002-01-01

    PURPOSE: The cell cycle is known to be deregulated in cancer. We therefore analyzed the expression of the cell cycle related proteins p21, p27, p16, Rb, and L-myc by immunohistochemical staining of bladder tumors.METHODS: The tissue material consisted of bladder tumors from three groups of patients...

  1. Quantitative characterization of cell behaviors through cell cycle progression via automated cell tracking.

    Directory of Open Access Journals (Sweden)

    Yuliang Wang

    Full Text Available Cell behaviors are reflections of intracellular tension dynamics and play important roles in many cellular processes. In this study, temporal variations in cell geometry and cell motion through cell cycle progression were quantitatively characterized via automated cell tracking for MCF-10A non-transformed breast cells, MCF-7 non-invasive breast cancer cells, and MDA-MB-231 highly metastatic breast cancer cells. A new cell segmentation method, which combines the threshold method and our modified edge based active contour method, was applied to optimize cell boundary detection for all cells in the field-of-view. An automated cell-tracking program was implemented to conduct live cell tracking over 40 hours for the three cell lines. The cell boundary and location information was measured and aligned with cell cycle progression with constructed cell lineage trees. Cell behaviors were studied in terms of cell geometry and cell motion. For cell geometry, cell area and cell axis ratio were investigated. For cell motion, instantaneous migration speed, cell motion type, as well as cell motion range were analyzed. We applied a cell-based approach that allows us to examine and compare temporal variations of cell behavior along with cell cycle progression at a single cell level. Cell body geometry along with distribution of peripheral protrusion structures appears to be associated with cell motion features. Migration speed together with motion type and motion ranges are required to distinguish the three cell-lines examined. We found that cells dividing or overlapping vertically are unique features of cell malignancy for both MCF-7 and MDA-MB-231 cells, whereas abrupt changes in cell body geometry and cell motion during mitosis are unique to highly metastatic MDA-MB-231 cells. Taken together, our live cell tracking system serves as an invaluable tool to identify cell behaviors that are unique to malignant and/or highly metastatic breast cancer cells.

  2. Lower concentrations of blueberry polyphenolic-rich extract differentially alter HepG2 cell proliferation and expression of genes related to cell-cycle, oxidation and epigenetic machinery

    Science.gov (United States)

    In vitro cancer models have been used to study the effect of relatively high concentrations (>200 ug/ml) of phenolic plant extracts upon cell proliferation. In this study we report that the treatment of human hepatocarcinoma HepG2 cells with lower concentrations of blueberry phenolic extract (6.5-10...

  3. Protein kinase C signaling and cell cycle regulation

    OpenAIRE

    Black, Adrian R.; Black, Jennifer D.

    2013-01-01

    A link between T cell proliferation and the protein kinase C (PKC) family of serine/threonine kinases has been recognized for about thirty years. However, despite the wealth of information on PKC-mediated control of T cell activation, understanding of the effects of PKCs on the cell cycle machinery in this cell type remains limited. Studies in other systems have revealed important cell cycle-specific effects of PKC signaling that can either positively or negatively impact proliferation. Th...

  4. Effects of Auraptene on IGF-1 Stimulated Cell Cycle Progression in the Human Breast Cancer Cell Line, MCF-7

    Directory of Open Access Journals (Sweden)

    Prasad Krishnan

    2012-01-01

    Full Text Available Auraptene is being investigated for its chemopreventive effects in many models of cancer including skin, colon, prostate, and breast. Many mechanisms of action including anti-inflammatory, antiproliferative, and antiapoptotic effects are being suggested for the chemopreventive properties of auraptene. We have previously shown in the N-methylnitrosourea induced mammary carcinogenesis model that dietary auraptene (500 ppm significantly delayed tumor latency. The delay in time to tumor corresponded with a significant reduction in cyclin D1 protein expression in the tumors. Since cyclin D1 is a major regulator of cell cycle, we further studied the effects of auraptene on cell cycle and the genes related to cell cycle in MCF-7 cells. Here we show that auraptene significantly inhibited IGF-1 stimulated S phase of cell cycle in MCF-7 cells and significantly changed the transcription of many genes involved in cell cycle.

  5. The ubiquitin-proteasome system in glioma cell cycle control

    Directory of Open Access Journals (Sweden)

    Vlachostergios Panagiotis J

    2012-07-01

    Full Text Available Abstract A major determinant of cell fate is regulation of cell cycle. Tight regulation of this process is lost during the course of development and progression of various tumors. The ubiquitin-proteasome system (UPS constitutes a universal protein degradation pathway, essential for the consistent recycling of a plethora of proteins with distinct structural and functional roles within the cell, including cell cycle regulation. High grade tumors, such as glioblastomas have an inherent potential of escaping cell cycle control mechanisms and are often refractory to conventional treatment. Here, we review the association of UPS with several UPS-targeted proteins and pathways involved in regulation of the cell cycle in malignant gliomas, and discuss the potential role of UPS inhibitors in reinstitution of cell cycle control.

  6. Effect of fenhexamid and cyprodinil on the expression of cell cycle- and metastasis-related genes via an estrogen receptor-dependent pathway in cellular and xenografted ovarian cancer models

    International Nuclear Information System (INIS)

    Go, Ryeo-Eun; Kim, Cho-Won; Choi, Kyung-Chul

    2015-01-01

    ABSTRACT: Fenhexamid and cyprodinil are antifungal agents (pesticides) used for agriculture, and are present at measurable amounts in fruits and vegetables. In the current study, the effects of fenhexamid and cyprodinil on cancer cell proliferation and metastasis were examined. Additionally, the protein expression levels of cyclin D1 and cyclin E as well as cathepsin D were analyzed in BG-1 ovarian cancer cells that express estrogen receptors (ERs). The cells were cultured with 0.1% dimethyl sulfoxide (DMSO; control), 17β-estradiol (E2; 10 −9 M), and fenhexamid or cyprodinil (10 –5 –10 −7 M). Results of a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay showed that fenhexamid and cyprodinil increased BG-1 cell proliferation about 1.5 to 2 times similar to E2 (5 times) compared to the control. When the cells were co-treated with ICI 182,780 (10 −8 M), an ER antagonist, the proliferation of pesticide-treated BG-1 cells was decreased to the level of the control. A wound healing assay revealed that the pesticides reduced the disrupted area in the BG-1 cell monolayer similar to E2. Protein levels of cyclin D1 and E as well as cathepsin D were increased by fenhexamid and cyprodinil. This effect was reversed by co-treatment with ICI 182,780. In a xenograft mouse model with transplanted BG-1 cells, cyprodinil significantly increased tumor mass formation about 2 times as did E2 (6 times) compared to the vehicle (0.1% DMSO) over an 80-day period. In contrast, fenhexamid did not promote ovarian tumor formation in this mouse model. Cyprodinil also induced cell proliferation along with the expression of proliferating cell nuclear antigen (PCNA) and cathepsin D in tumor tissues similar to E2. Taken together, these results imply that fenhexamid and cyprodinil may have disruptive effects on ER-expressing cancer by altering the cell cycle- and metastasis-related gene expression via an ER-dependent pathway. - Highlights: • Fenhexamid and

  7. Dysplasia in view of the cell cycle

    Directory of Open Access Journals (Sweden)

    RG Steinbeck

    2009-06-01

    Full Text Available Dysplasia is linked to altered tissue architecture. The lesion belongs into the diagnostic field of human pathology and is highly relevant for the clinical physician, because it breaks the criteria of hyperplasia and regeneration. Dysplasia is a precancerous disorder leading in all probability to malignant transformation if not treated. However, different descriptions do apply for dysplasia in different human tissues, and conventional pathology cannot arrive at unequivocal stringency. In contrast to the previous situation, now, dysplasia is defined by a unifying concept, which works upon cell cycle criteria. The decisive element for the proposed definition is unbalanced segregation of chromosomes and persistent genomic asymmetry through telophase, leading to aneuploid interphase nuclei. Progress of dysplasia can be estimated from the frequency of pathologic mitoses that directly measure cellular proliferation. In routine work, progress of dysplasia shall be quantified by frequency increase of aneuploidy in the increasing fraction of proliferating interphase nuclei. Thus, dysplasia is defined not only by aberrations from healthy histological architecture and normal cytological differentiation, but also by violations of the DNA standard from mitotic nuclei. The proposed classification of dysplasia measures the frequency of pathologic mitoses and the degree of genomic alterations in interphase nuclei. Both these criteria discriminate between low-grade and highgrade dysplasia and ascertain the malignant potential of a dysplastic lesion.

  8. Tempol inhibits growth of As4.1 juxtaglomerular cells via cell cycle arrest and apoptosis.

    Science.gov (United States)

    Han, Yong Hwan; Park, Woo Hyun

    2012-03-01

    A stable nitroxide 4-hydroxy-2,2,6,6-tetramethylpiperidine-N-osyl (Tempol) is widely used as an antioxidant in vitro and in vivo. In this study, we investigated the effects of Tempol on the growth of As4.1 juxtaglomerular cells in relation to cell cycle and cell death. Tempol dose-dependently decreased the growth of As4.1 cells with an IC50 of ~1 mM at 48 h. DNA flow cytometry analysis and BrdU staining indicated that Tempol induced S phase arrest, which is accompanied by a downregulation of cyclin A. Tempol also induced apoptotic cell death, which was accompanied by the loss of mitochondrial membrane potential (MMP; ∆Ψm), an activation of caspase-3 and cleavage of poly(ADP-ribose)polymerase-1 (PARP-1). Furthermore, Tempol increased reactive oxygen species (ROS) levels, and the phosphorylation of extracellular signal-regulated kinase (ERK) and c-Jun N-terminal kinase (JNK). MEK and JNK inhibitors significantly attenuated a growth inhibition in Tempol-treated As4.1 cells. In conclusion, Tempol inhibited the growth of As4.1 cells via cell cycle arrest and apoptosis. Tempol also activated ERK and JNK signaling, which was responsible for cell growth inhibition. Our present data provide useful information for the toxicological effects of Tempol in juxtaglomerular cells in relation to cell growth inhibition and cell death.

  9. Successive relaxation cycles during long-time cell aggregate rounding after uni-axial compression.

    Science.gov (United States)

    Pajic-Lijakovic, Ivana; Milivojevic, Milan

    2017-06-01

    The mean features of cell surface rearrangement during cell aggregate rounding after uni-axial compression between parallel plates are considered. This is based on long-time rheological modeling approaches in order to shed further light on collective cell migration. Many aspects of cell migration at the supra-cellular level, such as the coordination between surrounding migrating cell groups that leads to uncorrelated motility, have remained unclear. Aggregate shape changes during rounding are considered depending on the size and homogeneity of 2-D and 3-D cell aggregates. Cell aggregate shape changes that are taking place during successive relaxation cycles have various relaxation rates per cycle. Every relaxation rate is related to the corresponding cell migrating state. If most of the cells migrate per cycle, the relaxation rate is maximal. If most of the cells are in a resting state per cycle, the relaxation rate is nearing zero. If some cell groups migrate while the others, at the same time, stay in a resting state, the relaxation rate is lower than that obtained for the migrating cells. The relaxation rates per cycles are not random, but they have a tendency to gather around two or three values indicating an organized cell migrating pattern. Such behavior suggests that uncorrelated motility during collective cell migration in one cycle induces a decrease of the relaxation rate in the next cycle caused by an accumulation of cells in the resting state. However, cells have the ability to overcome these perturbations and re-establish an ordered migrating trend in the next cycle. These perturbations of the cell migrating state are more pronounced for: (1) more mobile cells, (2) a heterogeneous cell population, and (3) a larger cell population under the same experimental conditions.

  10. Age-related decrements in cycling and running perfor- mance

    African Journals Online (AJOL)

    Enrique

    This study examined age-related decrements in athletic performance during running and cycling activi- ties. Design. The age group winning times for males aged between 18 and 70 years competing in the 1999 Argus cycle tour (103 km) and 1999 Comrades running marathon (90 km), South Africa's premier endurance.

  11. Glucose capped silver nanoparticles induce cell cycle arrest in HeLa cells.

    Science.gov (United States)

    Panzarini, Elisa; Mariano, Stefania; Vergallo, Cristian; Carata, Elisabetta; Fimia, Gian Maria; Mura, Francesco; Rossi, Marco; Vergaro, Viviana; Ciccarella, Giuseppe; Corazzari, Marco; Dini, Luciana

    2017-06-01

    This study aims to determine the interaction (uptake and biological effects on cell viability and cell cycle progression) of glucose capped silver nanoparticles (AgNPs-G) on human epithelioid cervix carcinoma (HeLa) cells, in relation to amount, 2×10 3 or 2×10 4 NPs/cell, and exposure time, up to 48h. The spherical and well dispersed AgNPs (30±5nm) were obtained by using glucose as reducing agent in a green synthesis method that ensures to stabilize AgNPs avoiding cytotoxic soluble silver ions Ag + release. HeLa cells take up abundantly and rapidly AgNPs-G resulting toxic to cells in amount and incubation time dependent manner. HeLa cells were arrested at S and G2/M phases of the cell cycle and subG1 population increased when incubated with 2×10 4 AgNPs-G/cell. Mitotic index decreased accordingly. The dissolution experiments demonstrated that the observed effects were due only to AgNPs-G since glucose capping prevents Ag + release. The AgNPs-G influence on HeLa cells viability and cell cycle progression suggest that AgNPs-G, alone or in combination with chemotherapeutics, may be exploited for the development of novel antiproliferative treatment in cancer therapy. However, the possible influence of the cell cycle on cellular uptake of AgNPs-G and the mechanism of AgNPs entry in cells need further investigation. Copyright © 2017 Elsevier B.V. All rights reserved.

  12. Characterization and functional analysis of a slow-cycling subpopulation in colorectal cancer enriched by cell cycle inducer combined chemotherapy.

    Science.gov (United States)

    Wu, Feng-Hua; Mu, Lei; Li, Xiao-Lan; Hu, Yi-Bing; Liu, Hui; Han, Lin-Tao; Gong, Jian-Ping

    2017-10-03

    The concept of cancer stem cells has been proposed in various malignancies including colorectal cancer. Recent studies show direct evidence for quiescence slow-cycling cells playing a role in cancer stem cells. There exists an urgent need to isolate and better characterize these slow-cycling cells. In this study, we developed a new model to enrich slow-cycling tumor cells using cell-cycle inducer combined with cell cycle-dependent chemotherapy in vitro and in vivo . Our results show that Short-term exposure of colorectal cancer cells to chemotherapy combined with cell-cycle inducer enriches for a cell-cycle quiescent tumor cell population. Specifically, these slow-cycling tumor cells exhibit increased chemotherapy resistance in vitro and tumorigenicity in vivo . Notably, these cells are stem-cell like and participate in metastatic dormancy. Further exploration indicates that slow-cycling colorectal cancer cells in our model are less sensitive to cytokine-induced-killer cell mediated cytotoxic killing in vivo and in vitro . Collectively, our cell cycle inducer combined chemotherapy exposure model enriches for a slow-cycling, dormant, chemo-resistant tumor cell sub-population that are resistant to cytokine induced killer cell based immunotherapy. Studying unique signaling pathways in dormant tumor cells enriched by cell cycle inducer combined chemotherapy treatment is expected to identify novel therapeutic targets for preventing tumor recurrence.

  13. Eukaryotic checkpoints are absent in the cell division cycle of ...

    Indian Academy of Sciences (India)

    Unknown

    checkpoints' which are known to regulate the eukaryotic cell cycle may be absent or altered in. E. histolytica. [Banerjee S, Das S and Lohia A 2002 Eukaryotic checkpoints are absent in the cell division cycle of Entamoeba histolytica; J. Biosci. (Suppl.

  14. Variety in intracellular diffusion during the cell cycle

    DEFF Research Database (Denmark)

    Selhuber-Unkel, C.; Yde, P.; Berg-Sørensen, Kirstine

    2009-01-01

    Schizosaccharomyces Pombe using optical tweezers. The cell cycle was divided into interphase and mitotic cell division, and the mitotic cell division was further subdivided in its stages. During all stages of the cell cycle, the granules predominantly underwent subdiffusive motion, characterized by an exponent......During the cell cycle, the organization of the cytoskeletal network undergoes dramatic changes. In order to reveal possible changes of the viscoelastic properties in the intracellular space during the cell cycle we investigated the diffusion of endogenous lipid granules within the fission yeast...... a that is also linked to the viscoelastic moduli of the cytoplasm. The exponent a was significantly smaller during interphase than during any stage of the mitotic cell division, signifying that the cytoplasm was more elastic during interphase than during division. We found no significant differences...

  15. Tcf3 and cell cycle factors contribute to butyrate resistance in colorectal cancer cells

    International Nuclear Information System (INIS)

    Chiaro, Christopher; Lazarova, Darina L.; Bordonaro, Michael

    2012-01-01

    Highlights: ► We investigate mechanisms responsible for butyrate resistance in colon cancer cells. ► Tcf3 modulates butyrate’s effects on Wnt activity and cell growth in resistant cells. ► Tcf3 modulation of butyrate’s effects differ by cell context. ► Cell cycle factors are overexpressed in the resistant cells. ► Reversal of altered gene expression can enhance the anti-cancer effects of butyrate. -- Abstract: Butyrate, a fermentation product of dietary fiber, inhibits clonal growth in colorectal cancer (CRC) cells dependent upon the fold induction of Wnt activity. We have developed a CRC cell line (HCT-R) that, unlike its parental cell line, HCT-116, does not respond to butyrate exposure with hyperactivation of Wnt signaling and suppressed clonal growth. PCR array analyses revealed Wnt pathway-related genes, the expression of which differs between butyrate-sensitive HCT-116 CRC cells and their butyrate-resistant HCT-R cell counterparts. We identified overexpression of Tcf3 as being partially responsible for the butyrate-resistant phenotype, as this DNA-binding protein suppresses the hyperinduction of Wnt activity by butyrate. Consequently, Tcf3 knockdown in HCT-R cells restores their sensitivity to the effects of butyrate on Wnt activity and clonal cell growth. Interestingly, the effects of overexpressed Tcf3 differ between HCT-116 and HCT-R cells; thus, in HCT-116 cells Tcf3 suppresses proliferation without rendering the cells resistant to butyrate. In HCT-R cells, however, the overexpression of Tcf3 inhibits Wnt activity, and the cells are still able to proliferate due to the higher expression levels of cell cycle factors, particularly those driving the G 1 to S transition. Knowledge of the molecular mechanisms determining the variable sensitivity of CRC cells to butyrate may assist in developing approaches that prevent or reverse butyrate resistance.

  16. Tcf3 and cell cycle factors contribute to butyrate resistance in colorectal cancer cells

    Energy Technology Data Exchange (ETDEWEB)

    Chiaro, Christopher, E-mail: cchiaro@tcmedc.org [Department of Basic Sciences, The Commonwealth Medical College, 525 Pine Street, Scranton, PA 18509 (United States); Lazarova, Darina L., E-mail: dlazarova@tcmedc.org [Department of Basic Sciences, The Commonwealth Medical College, 525 Pine Street, Scranton, PA 18509 (United States); Bordonaro, Michael, E-mail: mbordonaro@tcmedc.org [Department of Basic Sciences, The Commonwealth Medical College, 525 Pine Street, Scranton, PA 18509 (United States)

    2012-11-09

    Highlights: Black-Right-Pointing-Pointer We investigate mechanisms responsible for butyrate resistance in colon cancer cells. Black-Right-Pointing-Pointer Tcf3 modulates butyrate's effects on Wnt activity and cell growth in resistant cells. Black-Right-Pointing-Pointer Tcf3 modulation of butyrate's effects differ by cell context. Black-Right-Pointing-Pointer Cell cycle factors are overexpressed in the resistant cells. Black-Right-Pointing-Pointer Reversal of altered gene expression can enhance the anti-cancer effects of butyrate. -- Abstract: Butyrate, a fermentation product of dietary fiber, inhibits clonal growth in colorectal cancer (CRC) cells dependent upon the fold induction of Wnt activity. We have developed a CRC cell line (HCT-R) that, unlike its parental cell line, HCT-116, does not respond to butyrate exposure with hyperactivation of Wnt signaling and suppressed clonal growth. PCR array analyses revealed Wnt pathway-related genes, the expression of which differs between butyrate-sensitive HCT-116 CRC cells and their butyrate-resistant HCT-R cell counterparts. We identified overexpression of Tcf3 as being partially responsible for the butyrate-resistant phenotype, as this DNA-binding protein suppresses the hyperinduction of Wnt activity by butyrate. Consequently, Tcf3 knockdown in HCT-R cells restores their sensitivity to the effects of butyrate on Wnt activity and clonal cell growth. Interestingly, the effects of overexpressed Tcf3 differ between HCT-116 and HCT-R cells; thus, in HCT-116 cells Tcf3 suppresses proliferation without rendering the cells resistant to butyrate. In HCT-R cells, however, the overexpression of Tcf3 inhibits Wnt activity, and the cells are still able to proliferate due to the higher expression levels of cell cycle factors, particularly those driving the G{sub 1} to S transition. Knowledge of the molecular mechanisms determining the variable sensitivity of CRC cells to butyrate may assist in developing approaches that

  17. Variation in traction forces during cell cycle progression.

    Science.gov (United States)

    Vianay, Benoit; Senger, Fabrice; Alamos, Simon; Anjur-Dietrich, Maya; Bearce, Elizabeth; Cheeseman, Bevan; Lee, Lisa; Théry, Manuel

    2018-02-01

    Tissue morphogenesis results from the interplay between cell growth and mechanical forces. While the impact of geometrical confinement and mechanical forces on cell proliferation has been fairly well characterised, the inverse relationship is much less understood. Here, we investigated how traction forces vary during cell cycle progression. Cell shape was constrained on micropatterned substrates in order to distinguish variations in cell contractility from cell size increase. We performed traction force measurements of asynchronously dividing cells expressing a cell-cycle reporter, to obtain measurements of contractile forces generated during cell division. We found that forces tend to increase as cells progress through G1, before reaching a plateau in S phase, and then decline during G2. While cell size increases regularly during cell cycle progression, traction forces follow a biphasic behaviour based on specific and opposite regulation of cell contractility during early and late growth phases. These results highlight the key role of cellular signalling in the regulation of cell contractility, independently of cell size and shape. Non-monotonous variations of cell contractility during cell cycle progression are likely to impact the mechanical regulation of tissue homoeostasis in a complex and non-linear manner. © 2018 Société Française des Microscopies and Société de Biologie Cellulaire de France. Published by John Wiley & Sons Ltd.

  18. Chromatin association of UHRF1 during the cell cycle

    KAUST Repository

    Al-Gashgari, Bothayna

    2017-05-01

    Ubiquitin-like with PHD and RING Finger domains 1 (UHRF1) is a nuclear protein that associates with chromatin. Regardless of the various functions of UHRF1 in the cell, one of its more important functions is its role in the maintenance of DNA methylation patterns by the recruitment of DNMT1. Studies on UHRF1 based on this function have revealed the importance of UHRF1 during the cell cycle. Moreover, based on different studies various factors were described to be involved in the regulation of UHRF1 with different functionalities that can control its binding affinity to different targets on chromatin. These factors are regulated differently in a cell cycle specific manner. In light of this, we propose that UHRF1 has different binding behaviors during the cell cycle in regard to its association with chromatin. In this project, we first analyzed the binding behavior of endogenous UHRF1 from different unsynchronized cell systems in pull-down assays with peptides and oligonucleotides. Moreover, to analyze UHRF1 binding behavior during the cell cycle, we used two different approaches. First we sorted Jurkat and HT1080 cells based on their cell cycle stage using FACS analysis. Additionally, we synchronized HeLa cells to different stages of the cell cycle by chemical treatments, and used extracts from cellsorting and cell synchronization experiments for pull-down assays. We observed that UHRF1 in different cell systems has different preferences in regard to its binding to H3 unmodified and H3K9me3. Moreover, we detected that UHRF1, in general, displays different patterns between different stages of cell cycle; however, we cannot draw a final model for UHRF1 binding pattern during cell cycle.

  19. Resveratrol causes cell cycle arrest, decreased collagen synthesis, and apoptosis in rat intestinal smooth muscle cells.

    Science.gov (United States)

    Garcia, Patricia; Schmiedlin-Ren, Phyllissa; Mathias, Jason S; Tang, Huaijing; Christman, Gregory M; Zimmermann, Ellen M

    2012-02-01

    One of the most difficult and treatment-resistant complications of Crohn's disease is the development of fibrotic intestinal strictures due to mesenchymal cell hyperplasia and collagen deposition. Resveratrol, a phytoalexin found in berries, peanuts, grapes, and red wine, has been shown to inhibit fibrosis in vasculature, heart, lung, kidney, liver, and esophagus in animal models. Resveratrol has also been shown to inhibit oxidation, inflammation, and cell proliferation and to decrease collagen synthesis in several cell types or animal models. The aim of this study was to determine whether resveratrol has antifibrotic effects on intestinal smooth muscle cells. Responses to resveratrol by cultured smooth muscle cells isolated from colons of untreated Lewis rats were examined; this rat strain is used in a model of Crohn's disease with prominent intestinal fibrosis. A relative decrease in cell numbers following treatment with 50 and 100 μM resveratrol was evident at 24 h (P ≤ 0.005). This effect was largely due to cell cycle arrest, with an increase in the percent of cells in S phase from 8 to 25-35% (P intestinal smooth muscle cell numbers through its effects on cell cycle arrest and apoptosis and also decreases collagen synthesis by the cells. These effects could be useful in preventing the smooth muscle cell hyperplasia and collagen deposition that characterize stricture formation in Crohn's disease.

  20. Genome organization during the cell cycle: unity in division.

    Science.gov (United States)

    Golloshi, Rosela; Sanders, Jacob T; McCord, Rachel Patton

    2017-09-01

    During the cell cycle, the genome must undergo dramatic changes in structure, from a decondensed, yet highly organized interphase structure to a condensed, generic mitotic chromosome and then back again. For faithful cell division, the genome must be replicated and chromosomes and sister chromatids physically segregated from one another. Throughout these processes, there is feedback and tension between the information-storing role and the physical properties of chromosomes. With a combination of recent techniques in fluorescence microscopy, chromosome conformation capture (Hi-C), biophysical experiments, and computational modeling, we can now attribute mechanisms to many long-observed features of chromosome structure changes during cell division. Apparent conflicts that arise when integrating the concepts from these different proposed mechanisms emphasize that orchestrating chromosome organization during cell division requires a complex system of factors rather than a simple pathway. Cell division is both essential for and threatening to proper genome organization. As interphase three-dimensional (3D) genome structure is quite static at a global level, cell division provides an important window of opportunity to make substantial changes in 3D genome organization in daughter cells, allowing for proper differentiation and development. Mistakes in the process of chromosome condensation or rebuilding the structure after mitosis can lead to diseases such as cancer, premature aging, and neurodegeneration. WIREs Syst Biol Med 2017, 9:e1389. doi: 10.1002/wsbm.1389 For further resources related to this article, please visit the WIREs website. © 2017 Wiley Periodicals, Inc.

  1. Cyclin A2: a genuine cell cycle regulator?

    Science.gov (United States)

    Bendris, Nawal; Loukil, Abdelhalim; Cheung, Caroline; Arsic, Nikola; Rebouissou, Cosette; Hipskind, Robert; Peter, Marion; Lemmers, Bénédicte; Blanchard, Jean Marie

    2012-12-01

    Abstract Cyclin A2 belongs to the core cell cycle regulators and participates in the control of both S phase and mitosis. However, several observations suggest that it is also endowed with other functions, and our recent data shed light on its involvement in cytoskeleton dynamic and cell motility. From the transcription of its gene to its posttranslational modifications, cyclin A2 regulation reveals the complexity of the regulatory network shaping cell cycle progression. We summarize our current knowledge on this cell cycle regulator and discuss recent findings raising the possibility that cyclin A2 might play a much broader role in epithelial tissues homeostasis.

  2. The Cell Cycle: An Activity Using Paper Plates to Represent Time Spent in Phases of the Cell Cycle

    Science.gov (United States)

    Scherer, Yvette D.

    2014-01-01

    In this activity, students are given the opportunity to combine skills in math and geometry for a biology lesson in the cell cycle. Students utilize the data they collect and analyze from an online onion-root-tip activity to create a paper-plate time clock representing a 24-hour cell cycle. By dividing the paper plate into appropriate phases of…

  3. Sparstolonin B inhibits pro-angiogenic functions and blocks cell cycle progression in endothelial cells.

    Science.gov (United States)

    Bateman, Henry R; Liang, Qiaoli; Fan, Daping; Rodriguez, Vanessa; Lessner, Susan M

    2013-01-01

    Sparstolonin B (SsnB) is a novel bioactive compound isolated from Sparganium stoloniferum, an herb historically used in Traditional Chinese Medicine as an anti-tumor agent. Angiogenesis, the process of new capillary formation from existing blood vessels, is dysregulated in many pathological disorders, including diabetic retinopathy, tumor growth, and atherosclerosis. In functional assays, SsnB inhibited endothelial cell tube formation (Matrigel method) and cell migration (Transwell method) in a dose-dependent manner. Microarray experiments with human umbilical vein endothelial cells (HUVECs) and human coronary artery endothelial cells (HCAECs) demonstrated differential expression of several hundred genes in response to SsnB exposure (916 and 356 genes, respectively, with fold change ≥2, pcell types showed significant overlap, including genes associated with cell proliferation and cell cycle. Flow cytometric cell cycle analysis of HUVECs treated with SsnB showed an increase of cells in the G1 phase and a decrease of cells in the S phase. Cyclin E2 (CCNE2) and Cell division cycle 6 (CDC6) are regulatory proteins that control cell cycle progression through the G1/S checkpoint. Both CCNE2 and CDC6 were downregulated in the microarray data. Real Time quantitative PCR confirmed that gene expression of CCNE2 and CDC6 in HUVECs was downregulated after SsnB exposure, to 64% and 35% of controls, respectively. The data suggest that SsnB may exert its anti-angiogenic properties in part by downregulating CCNE2 and CDC6, halting progression through the G1/S checkpoint. In the chick chorioallantoic membrane (CAM) assay, SsnB caused significant reduction in capillary length and branching number relative to the vehicle control group. Overall, SsnB caused a significant reduction in angiogenesis (ANOVA, p<0.05), demonstrating its ex vivo efficacy.

  4. Host Actin Polymerization Tunes the Cell Division Cycle of an Intracellular Pathogen

    Directory of Open Access Journals (Sweden)

    M. Sloan Siegrist

    2015-04-01

    Full Text Available Growth and division are two of the most fundamental capabilities of a bacterial cell. While they are well described for model organisms growing in broth culture, very little is known about the cell division cycle of bacteria replicating in more complex environments. Using a D-alanine reporter strategy, we found that intracellular Listeria monocytogenes (Lm spend a smaller proportion of their cell cycle dividing compared to Lm growing in broth culture. This alteration to the cell division cycle is independent of bacterial doubling time. Instead, polymerization of host-derived actin at the bacterial cell surface extends the non-dividing elongation period and compresses the division period. By decreasing the relative proportion of dividing Lm, actin polymerization biases the population toward cells with the highest propensity to form actin tails. Thus, there is a positive-feedback loop between the Lm cell division cycle and a physical interaction with the host cytoskeleton.

  5. S-phase-dependent cell cycle disturbances caused by Aleutian mink disease parvovirus

    DEFF Research Database (Denmark)

    Oleksiewicz, M.B.; Alexandersen, Søren

    1997-01-01

    arrest occurred exclusively in cells containing de novo-synthesized viral nonstructural (NS) proteins. Production of ADV NS proteins, indicative of ADV replication, was triggered during S-phase traverse. The NS+ cells that were generated during later parts of S phase did not undergo cytokinesis...... with subthreshold levels of ADV products through the late S/G(2) block and, consequently, that the binary pattern of ADV-induced cell cycle arrest may be governed merely by viral replication levels within a single S phase. Flow cytometric analysis of propidium iodide fluorescence and bromodeoxyuridine uptake showed......We examined replication of the autonomous parovirus Aleutian mink disease parovirus (ADV) in relation to cell cycle progression of permissive Crandell feline kidney (CRFK) cells. Flow cytometric analysis showed that ADV caused a composite, binary pattern of cell cycle arrest. ADV-induced cell cycle...

  6. Retinal degeneration depends on Bmi1 function and reactivation of cell cycle proteins.

    Science.gov (United States)

    Zencak, Dusan; Schouwey, Karine; Chen, Danian; Ekström, Per; Tanger, Ellen; Bremner, Rod; van Lohuizen, Maarten; Arsenijevic, Yvan

    2013-02-12

    The epigenetic regulator Bmi1 controls proliferation in many organs. Reexpression of cell cycle proteins such as cyclin-dependent kinases (CDKs) is a hallmark of neuronal apoptosis in neurodegenerative diseases. Here we address the potential role of Bmi1 as a key regulator of cell cycle proteins during neuronal apoptosis. We show that several cell cycle proteins are expressed in different models of retinal degeneration and required in the Rd1 photoreceptor death process. Deleting E2f1, a downstream target of CDKs, provided temporary protection in Rd1 mice. Most importantly, genetic ablation of Bmi1 provided extensive photoreceptor survival and improvement of retinal function in Rd1 mice, mediated by a decrease in cell cycle markers and regulators independent of p16(Ink4a) and p19(Arf). These data reveal that Bmi1 controls the cell cycle-related death process, highlighting this pathway as a promising therapeutic target for neuroprotection in retinal dystrophies.

  7. Glucose-ABL1-TOR Signaling Modulates Cell Cycle Tuning to Control Terminal Appressorial Cell Differentiation.

    Science.gov (United States)

    Marroquin-Guzman, Margarita; Sun, Guangchao; Wilson, Richard A

    2017-01-01

    The conserved target of rapamycin (TOR) pathway integrates growth and development with available nutrients, but how cellular glucose controls TOR function and signaling is poorly understood. Here, we provide functional evidence from the devastating rice blast fungus Magnaporthe oryzae that glucose can mediate TOR activity via the product of a novel carbon-responsive gene, ABL1, in order to tune cell cycle progression during infection-related development. Under nutrient-free conditions, wild type (WT) M. oryzae strains form terminal plant-infecting cells (appressoria) at the tips of germ tubes emerging from three-celled spores (conidia). WT appressorial development is accompanied by one round of mitosis followed by autophagic cell death of the conidium. In contrast, Δabl1 mutant strains undergo multiple rounds of accelerated mitosis in elongated germ tubes, produce few appressoria, and are abolished for autophagy. Treating WT spores with glucose or 2-deoxyglucose phenocopied Δabl1. Inactivating TOR in Δabl1 mutants or glucose-treated WT strains restored appressorium formation by promoting mitotic arrest at G1/G0 via an appressorium- and autophagy-inducing cell cycle delay at G2/M. Collectively, this work uncovers a novel glucose-ABL1-TOR signaling axis and shows it engages two metabolic checkpoints in order to modulate cell cycle tuning and mediate terminal appressorial cell differentiation. We thus provide new molecular insights into TOR regulation and cell development in response to glucose.

  8. Brucella abortus Cell Cycle and Infection Are Coordinated.

    Science.gov (United States)

    De Bolle, Xavier; Crosson, Sean; Matroule, Jean-Yves; Letesson, Jean-Jacques

    2015-12-01

    Brucellae are facultative intracellular pathogens. The recent development of methods and genetically engineered strains allowed the description of cell-cycle progression of Brucella abortus, including unipolar growth and the ordered initiation of chromosomal replication. B. abortus cell-cycle progression is coordinated with intracellular trafficking in the endosomal compartments. Bacteria are first blocked at the G1 stage, growth and chromosome replication being resumed shortly before reaching the intracellular proliferation compartment. The control mechanisms of cell cycle are similar to those reported for the bacterium Caulobacter crescentus, and they are crucial for survival in the host cell. The development of single-cell analyses could also be applied to other bacterial pathogens to investigate their cell-cycle progression during infection. Copyright © 2015 Elsevier Ltd. All rights reserved.

  9. Protein kinase C signaling and cell cycle regulation

    Directory of Open Access Journals (Sweden)

    Adrian R Black

    2013-01-01

    Full Text Available A link between T cell proliferation and the protein kinase C (PKC family of serine/threonine kinases has been recognized for about thirty years. However, despite the wealth of information on PKC-mediated control of T cell activation, understanding of the effects of PKCs on the cell cycle machinery in this cell type remains limited. Studies in other systems have revealed important cell cycle-specific effects of PKC signaling that can either positively or negatively impact proliferation. The outcome of PKC activation is highly context-dependent, with the precise cell cycle target(s and overall effects determined by the specific isozyme involved, the timing of PKC activation, the cell type, and the signaling environment. Although PKCs can regulate all stages of the cell cycle, they appear to predominantly affect G0/G1 and G2. PKCs can modulate multiple cell cycle regulatory molecules, including cyclins, cyclin-dependent kinases (cdks, cdk inhibitors and cdc25 phosphatases; however, evidence points to Cip/Kip cdk inhibitors and D-type cyclins as key mediators of PKC-regulated cell cycle-specific effects. Several PKC isozymes can target Cip/Kip proteins to control G0/G1→S and/or G2→M transit, while effects on D-type cyclins regulate entry into and progression through G1. Analysis of PKC signaling in T cells has largely focused on its roles in T cell activation; thus, observed cell cycle effects are mainly positive. A prominent role is emerging for PKCθ, with non-redundant functions of other isozymes also described. Additional evidence points to PKCδ as a negative regulator of the cell cycle in these cells. As in other cell types, context-dependent effects of individual isozymes have been noted in T cells, and Cip/Kip cdk inhibitors and D-type cyclins appear to be major PKC targets. Future studies are anticipated to take advantage of the similarities between these various systems to enhance understanding of PKC-mediated cell cycle regulation in

  10. Prevention, Evaluation, and Rehabilitation of Cycling-Related Injury.

    Science.gov (United States)

    Kotler, Dana H; Babu, Ashwin N; Robidoux, Greg

    2016-01-01

    The unique quality of the bicycle is its ability to accommodate a wide variety of injuries and disabilities. Cycling for recreation, transportation, and competition is growing nationwide, and has proven health and societal benefits. The demands of each type of cycling dictate the necessary equipment, as well as potential for injury. Prevention of cycling-related injury in both the athlete and the recreational cyclist involves understanding the common mechanisms for both traumatic and overuse injury, and early correction of strength and flexibility imbalances, technique errors, and bicycle fit.

  11. Estrogen receptor alpha is cell cycle-regulated and regulates the cell cycle in a ligand-dependent fashion.

    Science.gov (United States)

    JavanMoghadam, Sonia; Weihua, Zhang; Hunt, Kelly K; Keyomarsi, Khandan

    2016-06-17

    Estrogen receptor alpha (ERα) has been implicated in several cell cycle regulatory events and is an important predictive marker of disease outcome in breast cancer patients. Here, we aimed to elucidate the mechanism through which ERα influences proliferation in breast cancer cells. Our results show that ERα protein is cell cycle-regulated in human breast cancer cells and that the presence of 17-β-estradiol (E2) in the culture medium shortened the cell cycle significantly (by 4.5 hours, P fashion. These results provide the rationale for an effective treatment strategy that includes a cell cycle inhibitor in combination with a drug that lowers estrogen levels, such as an aromatase inhibitor, and an antiestrogen that does not result in the degradation of ERα, such as tamoxifen.

  12. Cell cycle progression in response to oxygen levels.

    Science.gov (United States)

    Ortmann, Brian; Druker, Jimena; Rocha, Sonia

    2014-09-01

    Hypoxia' or decreases in oxygen availability' results in the activation of a number of different responses at both the whole organism and the cellular level. These responses include drastic changes in gene expression, which allow the organism (or cell) to cope efficiently with the stresses associated with the hypoxic insult. A major breakthrough in the understanding of the cellular response to hypoxia was the discovery of a hypoxia sensitive family of transcription factors known as the hypoxia inducible factors (HIFs). The hypoxia response mounted by the HIFs promotes cell survival and energy conservation. As such, this response has to deal with important cellular process such as cell division. In this review, the integration of oxygen sensing with the cell cycle will be discussed. HIFs, as well as other components of the hypoxia pathway, can influence cell cycle progression. The role of HIF and the cell molecular oxygen sensors in the control of the cell cycle will be reviewed.

  13. The Mammalian Cell Cycle Regulates Parvovirus Nuclear Capsid Assembly

    Science.gov (United States)

    Riolobos, Laura; Domínguez, Carlos; Kann, Michael; Almendral, José M.

    2015-01-01

    It is unknown whether the mammalian cell cycle could impact the assembly of viruses maturing in the nucleus. We addressed this question using MVM, a reference member of the icosahedral ssDNA nuclear parvoviruses, which requires cell proliferation to infect by mechanisms partly understood. Constitutively expressed MVM capsid subunits (VPs) accumulated in the cytoplasm of mouse and human fibroblasts synchronized at G0, G1, and G1/S transition. Upon arrest release, VPs translocated to the nucleus as cells entered S phase, at efficiencies relying on cell origin and arrest method, and immediately assembled into capsids. In synchronously infected cells, the consecutive virus life cycle steps (gene expression, proteins nuclear translocation, capsid assembly, genome replication and encapsidation) proceeded tightly coupled to cell cycle progression from G0/G1 through S into G2 phase. However, a DNA synthesis stress caused by thymidine irreversibly disrupted virus life cycle, as VPs became increasingly retained in the cytoplasm hours post-stress, forming empty capsids in mouse fibroblasts, thereby impairing encapsidation of the nuclear viral DNA replicative intermediates. Synchronously infected cells subjected to density-arrest signals while traversing early S phase also blocked VPs transport, resulting in a similar misplaced cytoplasmic capsid assembly in mouse fibroblasts. In contrast, thymidine and density arrest signals deregulating virus assembly neither perturbed nuclear translocation of the NS1 protein nor viral genome replication occurring under S/G2 cycle arrest. An underlying mechanism of cell cycle control was identified in the nuclear translocation of phosphorylated VPs trimeric assembly intermediates, which accessed a non-conserved route distinct from the importin α2/β1 and transportin pathways. The exquisite cell cycle-dependence of parvovirus nuclear capsid assembly conforms a novel paradigm of time and functional coupling between cellular and virus life

  14. The Mammalian Cell Cycle Regulates Parvovirus Nuclear Capsid Assembly.

    Science.gov (United States)

    Gil-Ranedo, Jon; Hernando, Eva; Riolobos, Laura; Domínguez, Carlos; Kann, Michael; Almendral, José M

    2015-06-01

    It is unknown whether the mammalian cell cycle could impact the assembly of viruses maturing in the nucleus. We addressed this question using MVM, a reference member of the icosahedral ssDNA nuclear parvoviruses, which requires cell proliferation to infect by mechanisms partly understood. Constitutively expressed MVM capsid subunits (VPs) accumulated in the cytoplasm of mouse and human fibroblasts synchronized at G0, G1, and G1/S transition. Upon arrest release, VPs translocated to the nucleus as cells entered S phase, at efficiencies relying on cell origin and arrest method, and immediately assembled into capsids. In synchronously infected cells, the consecutive virus life cycle steps (gene expression, proteins nuclear translocation, capsid assembly, genome replication and encapsidation) proceeded tightly coupled to cell cycle progression from G0/G1 through S into G2 phase. However, a DNA synthesis stress caused by thymidine irreversibly disrupted virus life cycle, as VPs became increasingly retained in the cytoplasm hours post-stress, forming empty capsids in mouse fibroblasts, thereby impairing encapsidation of the nuclear viral DNA replicative intermediates. Synchronously infected cells subjected to density-arrest signals while traversing early S phase also blocked VPs transport, resulting in a similar misplaced cytoplasmic capsid assembly in mouse fibroblasts. In contrast, thymidine and density arrest signals deregulating virus assembly neither perturbed nuclear translocation of the NS1 protein nor viral genome replication occurring under S/G2 cycle arrest. An underlying mechanism of cell cycle control was identified in the nuclear translocation of phosphorylated VPs trimeric assembly intermediates, which accessed a non-conserved route distinct from the importin α2/β1 and transportin pathways. The exquisite cell cycle-dependence of parvovirus nuclear capsid assembly conforms a novel paradigm of time and functional coupling between cellular and virus life

  15. Dual Pressure versus Hybrid Recuperation in an Integrated Solid Oxide Fuel Cell Cycle – Steam Cycle

    DEFF Research Database (Denmark)

    Rokni, Masoud

    2014-01-01

    A SOFC (solid oxide fuel cell) cycle running on natural gas was integrated with a ST (steam turbine) cycle. The fuel is desulfurized and pre-reformed before entering the SOFC. A burner was used to combust the remaining fuel after the SOFC stacks. The off-gases from the burner were used to produce...... steam in a HRSG (heat recovery steam generator). The bottoming steam cycle was modeled with two configurations: (1) a simple single pressure level and (2) a dual pressure level with both a reheat and a pre-heater. The SOFC stacks in the present SOFC-ST hybrid cycles were not pressurized. The dual...... pressure configuration steam cycle combined with SOFC cycle (SOFC-ST) was new and has not been studied previously. In each of the configuration, a hybrid recuperator was used to recovery the remaining energy of the off-gases after the HRSG. Thus, four different plants system setups were compared to each...

  16. The Chlamydomonas reinhardtii LI818 gene represents a distant relative of the cabI/II genes that is regulated during the cell cycle and in response to illumination.

    Science.gov (United States)

    Savard, F; Richard, C; Guertin, M

    1996-11-01

    In the green unicellular alga Chlamydomonas reinhardtii, as in higher plants, the expression of the genes encoding the chlorophyll a/b-binding (CAB) polypeptides associated with photosystem I (PSI) and photosystem II (PSII) is regulated by endogenous (circadian clock) and exogenous signals (light and temperature). The circadian clock ensures that the oscillation in the levels of the different cab mRNAs is continuously kept in phase with light/dark (LD) cycles and is maximal by the middle of the day. On the other hand, light controls the amplitude of the oscillations. We report here the cloning and characterization of the C. reinhardtii LI818 gene, which identifies a CAB-related polypeptide and whose expression is regulated quite differently from the cab I/II genes. We show: (1) that in LD synchronized Chlamydomonas cells LI818 mRNA accumulation is subject to dual regulation that involves separable regulation by light and an endogenous oscillator; (2) that LI818 mRNA is fully expressed several hours before the cab I/II mRNAs and that the latter accumulate concomitantly; (3) that blocking the electron flow through PSII using DCMU prevents cells from accumulating cab I/II mRNAs but not LI818 mRNA and (4) that the accumulation of LI818 mRNA is abolished by blocking cytoplasmic protein synthesis, suggesting that these regulatory mechanisms are mediated by labile proteins.

  17. Studies on regulation of the cell cycle in fission yeast.

    Directory of Open Access Journals (Sweden)

    Miroslava Požgajová

    2015-05-01

    Full Text Available All living organisms including plants and animals are composed of millions of cells. These cells perform different functions for the organism although they possess the same chromosomes and carry the same genetic information. Thus, to be able to understand multicellular organism we need to understand the life cycle of individual cells from which the organism comprises. The cell cycle is the life cycle of a single cell in the plant or animal body. It involves series of events in which components of the cell doubles and afterwards equally segregate into daughter cells. Such process ensures growth of the organism, and specialized reductional cell division which leads to production of gamets, assures sexual reproduction. Cell cycle is divided in the G1, S, G2 and M phase. Two gap-phases (G1 and G2 separate S phase (or synthesis and M phase which stays either for mitosis or meiosis. Essential for normal life progression and reproduction is correct chromosome segregation during mitosis and meiosis. Defects in the division program lead to aneuploidy, which in turn leads to birth defects, miscarriages or cancer. Even thou, researchers invented much about the regulation of the cell cycle, there is still long way to understand the complexity of the regulatory machineries that ensure proper segregation of chromosomes. In this paper we would like to describe techniques and materials we use for our studies on chromosome segregation in the model organism Schizosaccharomyces pombe.

  18. Cell cycle arrest and cell survival induce reverse trends of cardiolipin remodeling.

    Directory of Open Access Journals (Sweden)

    Yu-Jen Chao

    Full Text Available Cell survival from the arrested state can be a cause of the cancer recurrence. Transition from the arrest state to the growth state is highly regulated by mitochondrial activity, which is related to the lipid compositions of the mitochondrial membrane. Cardiolipin is a critical phospholipid for the mitochondrial integrity and functions. We examined the changes of cardiolipin species by LC-MS in the transition between cell cycle arrest and cell reviving in HT1080 fibrosarcoma cells. We have identified 41 cardiolipin species by MS/MS and semi-quantitated them to analyze the detailed changes of cardiolipin species. The mass spectra of cardiolipin with the same carbon number form an envelope, and the C64, C66, C68, C70 C72 and C74 envelopes in HT1080 cells show a normal distribution in the full scan mass spectrum. The cardiolipin quantity in a cell decreases while entering the cell cycle arrest, but maintains at a similar level through cell survival. While cells awakening from the arrested state and preparing itself for replication, the groups with short acyl chains, such as C64, C66 and C68 show a decrease of cardiolipin percentage, but the groups with long acyl chains, such as C70 and C72 display an increase of cardiolipin percentage. Interestingly, the trends of the cardiolipin species changes during the arresting state are completely opposite to cell growing state. Our results indicate that the cardiolipin species shift from the short chain to long chain cardiolipin during the transition from cell cycle arrest to cell progression.

  19. Life cycle assessment of a wind farm and related externalities

    DEFF Research Database (Denmark)

    Schleisner, Liselotte

    2000-01-01

    This paper concentrates on the assessment of energy and emissions related to the production and manufacture of materials for an offshore wind farm as well as a wind farm on land based on a life cycle analysis (LCA) model. In Denmark a model has been developed for life cycle assessments of differe......, and the model is demonstrated for two wind farms. The externalities for the wind farms are reported, showing the importance of life cycle assessment for renewable energy technologies. (C) 2000 Elsevier Science Ltd. All rights reserved.......This paper concentrates on the assessment of energy and emissions related to the production and manufacture of materials for an offshore wind farm as well as a wind farm on land based on a life cycle analysis (LCA) model. In Denmark a model has been developed for life cycle assessments of different...... materials. The model is able to assess the energy use related to the production, transportation and manufacture of 1 kg of material. The energy use is divided into fuels used in order to estimate the emissions through the life cycle. In the paper the model and the attached assumptions are described...

  20. Zebularine inhibits the growth of A549 lung cancer cells via cell cycle arrest and apoptosis.

    Science.gov (United States)

    You, Bo Ra; Park, Woo Hyun

    2014-11-01

    Zebularine (Zeb) is a DNA methyltransferase (DNMT) inhibitor to that has an anti-tumor effect. Here, we evaluated the anti-growth effect of Zeb on A549 lung cancer cells in relation to reactive oxygen species (ROS) levels. Zeb inhibited the growth of A549 cells with an IC50 of approximately 70 µM at 72 h. Cell cycle analysis indicated that Zeb induced an S phase arrest in A549 cells. Zeb also induced A549 cell death, which was accompanied by the loss of mitochondrial membrane potential (MMP; ΔΨm ), Bcl-2 decrease, Bax increase, p53 increase and activation of caspase-3 and -8. In contrast, Zeb mildly inhibited the growth of human pulmonary fibroblast (HPF) normal cells and lead to a G1 phase arrest. Zeb did not induce apoptosis in HPF cells. In relation to ROS level, Zeb increased ROS level in A549 cells and induced glutathione (GSH) depletion. The well-known antioxidant, N-acetyl cysteine (NAC) prevented the death of Zeb-treated A549 cells. Moreover, Zeb increased the level of thioredoxin reductase 1 (TrxR1) in A549 cells. While the overexpression of TrxR1 attenuated death and ROS level in Zeb-treated A549 cells, the downregulation of TrxR1 intensified death and ROS level in these cells. In conclusion, Zeb inhibited the growth of A549 lung cancer cells via cell cycle arrest and apoptosis. The inhibition was influenced by ROS and TrxR1 levels. © 2013 Wiley Periodicals, Inc.

  1. Krebs cycle rewired for macrophage and dendritic cell effector functions.

    Science.gov (United States)

    Ryan, Dylan Gerard; O'Neill, Luke A J

    2017-10-01

    The Krebs cycle is an amphibolic pathway operating in the mitochondrial matrix of all eukaryotic organisms. In response to proinflammatory stimuli, macrophages and dendritic cells undergo profound metabolic remodelling to support the biosynthetic and bioenergetic requirements of the cell. Recently, it has been discovered that this metabolic shift also involves the rewiring of the Krebs cycle to regulate cellular metabolic flux and the accumulation of Krebs cycle intermediates, notably, citrate, succinate and fumarate. Interestingly, a new role for Krebs cycle intermediates as signalling molecules and immunomodulators that dictate the inflammatory response has begun to emerge. This review will discuss the latest developments in Krebs cycle rewiring and immune cell effector functions, with a particular focus on the regulation of cytokine production. © 2017 Federation of European Biochemical Societies.

  2. Microsporidia infection impacts the host cell's cycle and reduces host cell apoptosis

    Science.gov (United States)

    Higes, Mariano; Sagastume, Soledad; Juarranz, Ángeles; Dias-Almeida, Joyce; Budge, Giles E.; Meana, Aránzazu; Boonham, Neil

    2017-01-01

    Intracellular parasites can alter the cellular machinery of host cells to create a safe haven for their survival. In this regard, microsporidia are obligate intracellular fungal parasites with extremely reduced genomes and hence, they are strongly dependent on their host for energy and resources. To date, there are few studies into host cell manipulation by microsporidia, most of which have focused on morphological aspects. The microsporidia Nosema apis and Nosema ceranae are worldwide parasites of honey bees, infecting their ventricular epithelial cells. In this work, quantitative gene expression and histology were studied to investigate how these two parasites manipulate their host’s cells at the molecular level. Both these microsporidia provoke infection-induced regulation of genes involved in apoptosis and the cell cycle. The up-regulation of buffy (which encodes a pro-survival protein) and BIRC5 (belonging to the Inhibitor Apoptosis protein family) was observed after infection, shedding light on the pathways that these pathogens use to inhibit host cell apoptosis. Curiously, different routes related to cell cycle were modified after infection by each microsporidia. In the case of N. apis, cyclin B1, dacapo and E2F2 were up-regulated, whereas only cyclin E was up-regulated by N. ceranae, in both cases promoting the G1/S phase transition. This is the first report describing molecular pathways related to parasite-host interactions that are probably intended to ensure the parasite’s survival within the cell. PMID:28152065

  3. Regulation of cell cycle by the anaphase spindle midzone

    Directory of Open Access Journals (Sweden)

    Sluder Greenfield

    2004-12-01

    Full Text Available Abstract Background A number of proteins accumulate in the spindle midzone and midbody of dividing animal cells. Besides proteins essential for cytokinesis, there are also components essential for interphase functions, suggesting that the spindle midzone and/or midbody may play a role in regulating the following cell cycle. Results We microsurgically severed NRK epithelial cells during anaphase or telophase, such that the spindle midzone/midbody was associated with only one of the daughter cells. Time-lapse recording of cells severed during early anaphase indicated that the cell with midzone underwent cytokinesis-like cortical contractions and progressed normally through the interphase, whereas the cell without midzone showed no cortical contraction and an arrest or substantial delay in the progression of interphase. Similar microsurgery during telophase showed a normal progression of interphase for both daughter cells with or without the midbody. Microsurgery of anaphase cells treated with cytochalasin D or nocodazole indicated that interphase progression was independent of cortical ingression but dependent on microtubules. Conclusions We conclude that the mitotic spindle is involved in not only the separation of chromosomes but also the regulation of cell cycle. The process may involve activation of components in the spindle midzone that are required for the cell cycle, and/or degradation of components that are required for cytokinesis but may interfere with the cell cycle.

  4. Genome-wide examination of myoblast cell cycle withdrawal duringdifferentiation

    Energy Technology Data Exchange (ETDEWEB)

    Shen, Xun; Collier, John Michael; Hlaing, Myint; Zhang, Leanne; Delshad, Elizabeth H.; Bristow, James; Bernstein, Harold S.

    2002-12-02

    Skeletal and cardiac myocytes cease division within weeks of birth. Although skeletal muscle retains limited capacity for regeneration through recruitment of satellite cells, resident populations of adult myocardial stem cells have not been identified. Because cell cycle withdrawal accompanies myocyte differentiation, we hypothesized that C2C12 cells, a mouse myoblast cell line previously used to characterize myocyte differentiation, also would provide a model for studying cell cycle withdrawal during differentiation. C2C12 cells were differentiated in culture medium containing horse serum and harvested at various time points to characterize the expression profiles of known cell cycle and myogenic regulatory factors by immunoblot analysis. BrdU incorporation decreased dramatically in confluent cultures 48 hr after addition of horse serum, as cells started to form myotubes. This finding was preceded by up-regulation of MyoD, followed by myogenin, and activation of Bcl-2. Cyclin D1 was expressed in proliferating cultures and became undetectable in cultures containing 40 percent fused myotubes, as levels of p21(WAF1/Cip1) increased and alpha-actin became detectable. Because C2C12 myoblasts withdraw from the cell cycle during myocyte differentiation following a course that recapitulates this process in vivo, we performed a genome-wide screen to identify other gene products involved in this process. Using microarrays containing approximately 10,000 minimally redundant mouse sequences that map to the UniGene database of the National Center for Biotechnology Information, we compared gene expression profiles between proliferating, differentiating, and differentiated C2C12 cells and verified candidate genes demonstrating differential expression by RT-PCR. Cluster analysis of differentially expressed genes revealed groups of gene products involved in cell cycle withdrawal, muscle differentiation, and apoptosis. In addition, we identified several genes, including DDAH2 and Ly

  5. Methyl Jasmonate: Putative Mechanisms of Action on Cancer Cells Cycle, Metabolism, and Apoptosis

    OpenAIRE

    Cesari, Italo Mario; Carvalho, Erika; Figueiredo Rodrigues, Mariana; Mendonça, Bruna dos Santos; Amôedo, Nivea Dias; Rumjanek, Franklin David

    2014-01-01

    Methyl jasmonate (MJ), an oxylipid that induces defense-related mechanisms in plants, has been shown to be active against cancer cells both in vitro and in vivo, without affecting normal cells. Here we review most of the described MJ activities in an attempt to get an integrated view and better understanding of its multifaceted modes of action. MJ (1) arrests cell cycle, inhibiting cell growth and proliferation, (2) causes cell death through the intrinsic/extrinsic proapoptotic, p53-independe...

  6. Flow Cytometry Analysis of Cell Cycle and Specific Cell Synchronization with Butyrate.

    Science.gov (United States)

    Li, Cong-Jun

    2017-01-01

    Synchronized cells have been invaluable in many kinds of cell cycle and cell proliferation studies. Butyrate induces cell cycle arrest and apoptosis in MDBK cells. We explore the possibility of using butyrate-blocked cells to obtain synchronized cells and we characterize the properties of butyrate-induced cell cycle arrest. The site of growth inhibition and cell cycle arrest was analyzed using 5-bromo-2'-deoxyuridine (BrdU) incorporation and flow cytometry analyses. Exposure of MDBK cells to 10 mM butyrate caused growth inhibition and cell cycle arrest in a reversible manner. Butyrate affected the cell cycle at a specific point both immediately after mitosis and at a very early stage of the G1 phase. After release from butyrate arrest, MDBK cells underwent synchronous cycles of DNA synthesis and transited through the S phase. It takes at least 8 h for butyrate-induced G1-synchronized cells to begin the progression into the S phase. One cycle of cell division for MDBK cells is about 20 h. By combining BrdU incorporation and DNA content analysis, not only can the overlapping of different cell populations be eliminated, but the frequency and nature of individual cells that have synthesized DNA can be determined.

  7. Arctigenin induces cell cycle arrest by blocking the phosphorylation of Rb via the modulation of cell cycle regulatory proteins in human gastric cancer cells.

    Science.gov (United States)

    Jeong, Jin Boo; Hong, Se Chul; Jeong, Hyung Jin; Koo, Jin Suk

    2011-10-01

    Gastric cancer is a leading cause of cancer-related deaths, worldwide being second only to lung cancer as a cause of death. Arctigenin, a representative dibenzylbutyrolactone lignan, occurs in a variety of plants. However, the molecular mechanisms of arctigenin for anti-tumor effect on gastric cancer have not been examined. This study examined the biological effects of arctigenin on the human gastric cancer cell line SNU-1 and AGS. Cell proliferation was determined by MTT assay. In MTT assay, the proliferation of SNU-1 and AGS cells was significantly inhibited by arctigenin in a time and dose dependent manner, as compared with SNU-1 and AGS cells cultured in the absence of arctigenin. Inhibition of cell proliferation by arctigenin was in part associated with apoptotic cell death, as shown by changes in the expression ratio of Bcl-2 to Bax by arctigenin. Also, arctigenin blocked cell cycle arrest from G(1) to S phase by regulating the expression of cell cycle regulatory proteins such as Rb, cyclin D1, cyclin E, CDK4, CDK2, p21Waf1/Cip1 and p15 INK4b. The antiproliferative effect of arctigenin on SNU-1 and AGS gastric cancer cells revealed in this study suggests that arctigenin has intriguing potential as a chemopreventive or chemotherapeutic agent. Crown Copyright © 2011. Published by Elsevier B.V. All rights reserved.

  8. The Complex Relationship between Liver Cancer and the Cell Cycle: A Story of Multiple Regulations

    Energy Technology Data Exchange (ETDEWEB)

    Bisteau, Xavier [Institute of Molecular and Cell Biology (IMCB), A*STAR (Agency for Science, Technology and Research), 61 Biopolis Drive, Proteos#3-09, Singapore 138673 (Singapore); Caldez, Matias J.; Kaldis, Philipp, E-mail: kaldis@imcb.a-star.edu.sg [Institute of Molecular and Cell Biology (IMCB), A*STAR (Agency for Science, Technology and Research), 61 Biopolis Drive, Proteos#3-09, Singapore 138673 (Singapore); National University of Singapore (NUS), Department of Biochemistry, Singapore 117597 (Singapore)

    2014-01-13

    The liver acts as a hub for metabolic reactions to keep a homeostatic balance during development and growth. The process of liver cancer development, although poorly understood, is related to different etiologic factors like toxins, alcohol, or viral infection. At the molecular level, liver cancer is characterized by a disruption of cell cycle regulation through many molecular mechanisms. In this review, we focus on the mechanisms underlying the lack of regulation of the cell cycle during liver cancer, focusing mainly on hepatocellular carcinoma (HCC). We also provide a brief summary of novel therapies connected to cell cycle regulation.

  9. Cell division cycle 20 promotes cell proliferation and invasion and inhibits apoptosis in osteosarcoma cells.

    Science.gov (United States)

    Shang, Guanning; Ma, Xu; Lv, Gang

    2018-01-01

    Cdc20 (cell division cycle 20 homologue) has been reported to exhibit an oncogenic role in human tumorigenesis. However, the function of Cdc20 in osteosarcoma (OS) has not been investigated. In the current study, we aim to explore the role of Cdc20 in human OS cells. Multiple approaches were used to measure cell growth, apoptosis, cell cycle, migration and invasion in OS cells after depletion of Cdc20 or overexpression of Cdc20. We found that down-regulation of Cdc20 inhibited cell growth, induced apoptosis and triggered cell cycle arrest in OS cells. Moreover, Cdc20 down-regulation let to inhibition of cell migration and invasion in OS cells. Consistently, overexpression of Cdc20 in OS cells promoted cell growth, inhibited apoptosis, enhanced cell migration and invasion. Mechanistically, our Western blotting results showed that overexpression of Cdc20 reduced the expression of Bim and p21, whereas depletion of Cdc20 upregulated Bim and p21 levels in OS cells. Altogether, our findings demonstrated that Cdc20 exerts its oncogenic role partly due to regulation of Bim and p21 in OS cells, suggesting that targeting Cdc20 could be useful for the treatment of OS.

  10. Cellular Clocks : Coupled Circadian Dispatch and Cell Division Cycles

    NARCIS (Netherlands)

    Merrow, Martha; Roenneberg, Till

    2004-01-01

    Gating of cell division by the circadian clock is well known, yet its mechanism is little understood. Genetically tractable model systems have led to new hypotheses and questions concerning the coupling of these two cellular cycles.

  11. Technoeconomy of different solid oxide fuel cell based hybrid cycle

    DEFF Research Database (Denmark)

    Rokni, Masoud

    2014-01-01

    Gas turbine, steam turbine and heat engine (Stirling engine) is used as bottoming cycle for a solid oxide fuel cell plant to compare different plants efficiencies, CO2 emissionsand plants cost in terms of $/kW. Each plant is then integrated with biomass gasification and finally six plants...... configurations are compared with each other. Technoeconomy is used when calculating the cost if the plants. It is found that when a solid oxide fuel cell plant is combined with a gas turbine cycle then the plant efficiency will be the highest one while if a biomass gasification plant is integrated...... with these hybrid cycles then integrated biomass gasification with solid oxide fuel cell and steam cycle will have the highest plant efficiency. The cost of solid oxide fuel cell with steam plant is found to be the lowest one with a value of about 1030$/kW....

  12. Does Arabidopsis thaliana DREAM of cell cycle control?

    OpenAIRE

    Fischer, Martin; DeCaprio, James A

    2015-01-01

    Strict temporal control of cell cycle gene expression is essential for all eukaryotes including animals and plants. DREAM complexes have been identified in worm, fly, and mammals, linking several distinct transcription factors to coordinate gene expression throughout the cell cycle. In this issue of The EMBO Journal, Kobayashi et al (2015) identify distinct activator and repressor complexes for genes expressed during the G2 and M phases in Arabidopsis that can be temporarily separated during ...

  13. Cell cycle regulation by the bacterial nucleoid

    OpenAIRE

    Adams, David William; Wu, Ling Juan; Errington, Jeff

    2014-01-01

    Division site selection presents a fundamental challenge to all organisms. Bacterial cells are small and the chromosome (nucleoid) often fills most of the cell volume. Thus, in order to maximise fitness and avoid damaging the genetic material, cell division must be tightly co-ordinated with chromosome replication and segregation. To achieve this, bacteria employ a number of different mechanisms to regulate division site selection. One such mechanism, termed nucleoid occlusion, allows the nucl...

  14. A data integration approach for cell cycle analysis oriented to model simulation in systems biology

    Directory of Open Access Journals (Sweden)

    Mosca Ettore

    2007-08-01

    Full Text Available Abstract Background The cell cycle is one of the biological processes most frequently investigated in systems biology studies and it involves the knowledge of a large number of genes and networks of protein interactions. A deep knowledge of the molecular aspect of this biological process can contribute to making cancer research more accurate and innovative. In this context the mathematical modelling of the cell cycle has a relevant role to quantify the behaviour of each component of the systems. The mathematical modelling of a biological process such as the cell cycle allows a systemic description that helps to highlight some features such as emergent properties which could be hidden when the analysis is performed only from a reductionism point of view. Moreover, in modelling complex systems, a complete annotation of all the components is equally important to understand the interaction mechanism inside the network: for this reason data integration of the model components has high relevance in systems biology studies. Description In this work, we present a resource, the Cell Cycle Database, intended to support systems biology analysis on the Cell Cycle process, based on two organisms, yeast and mammalian. The database integrates information about genes and proteins involved in the cell cycle process, stores complete models of the interaction networks and allows the mathematical simulation over time of the quantitative behaviour of each component. To accomplish this task, we developed, a web interface for browsing information related to cell cycle genes, proteins and mathematical models. In this framework, we have implemented a pipeline which allows users to deal with the mathematical part of the models, in order to solve, using different variables, the ordinary differential equation systems that describe the biological process. Conclusion This integrated system is freely available in order to support systems biology research on the cell cycle and

  15. Thermally regenerative hydrogen/oxygen fuel cell power cycles

    Science.gov (United States)

    Morehouse, J. H.

    1986-01-01

    Two innovative thermodynamic power cycles are analytically examined for future engineering feasibility. The power cycles use a hydrogen-oxygen fuel cell for electrical energy production and use the thermal dissociation of water for regeneration of the hydrogen and oxygen. The TDS (thermal dissociation system) uses a thermal energy input at over 2000 K to thermally dissociate the water. The other cycle, the HTE (high temperature electrolyzer) system, dissociates the water using an electrolyzer operating at high temperature (1300 K) which receives its electrical energy from the fuel cell. The primary advantages of these cycles is that they are basically a no moving parts system, thus having the potential for long life and high reliability, and they have the potential for high thermal efficiency. Both cycles are shown to be classical heat engines with ideal efficiency close to Carnot cycle efficiency. The feasibility of constructing actual cycles is investigated by examining process irreversibilities and device efficiencies for the two types of cycles. The results show that while the processes and devices of the 2000 K TDS exceed current technology limits, the high temperature electrolyzer system appears to be a state-of-the-art technology development. The requirements for very high electrolyzer and fuel cell efficiencies are seen as determining the feasbility of the HTE system, and these high efficiency devices are currently being developed. It is concluded that a proof-of-concept HTE system experiment can and should be conducted.

  16. DNA Damage and Cell Cycle Arrest Induced by Protoporphyrin IX in Sarcoma 180 Cells

    Directory of Open Access Journals (Sweden)

    Qing Li

    2013-09-01

    Full Text Available Background: Porphyrin derivatives have been widely used in photodynamic therapy as effective sensitizers. Protoporphyrin IX (PpIX, a well-known hematoporphyrin derivative component, shows great potential to enhance light induced tumor cell damage. However, PpIX alone could also exert anti-tumor effects. The mechanisms underlying those direct effects are incompletely understood. This study thus investigated the putative mechanisms underlying the anti-tumor effects of PpIX on sarcoma 180 (S180 cells. Methods: S180 cells were treated with different concentrations of PpIX. Following the treatment, cell viability was evaluated by the 3-(4, 5- dimethylthiazol-2-yl-2, 5-diphenyltetrazoliumbromide (MTT assay; Disruption of mitochondrial membrane potential was measured by flow cytometry; The trans-location of apoptosis inducer factor (AIF from mitochondria to nucleus was visualized by confocal laser scanning microscopy; DNA damage was detected by single cell gel electrophoresis; Cell cycle distribution was analyzed by DNA content with flow cytometry; Cell cycle associated proteins were detected by western blotting. Results: PpIX (≥ 1 µg/ml significantly inhibited proliferation and reduced viability of S180 cells in a dose-dependent manner. PpIX rapidly and significantly triggered mitochondrial membrane depolarization, AIF (apoptosis inducer factor translocation from mitochondria to nucleus and DNA damage, effects partially relieved by the specific inhibitor of MPTP (mitochondrial permeability transition pore. Furthermore, S phase arrest and upregulation of the related proteins of P53 and P21 were observed following 12 and 24 h PpIX exposure. Conclusion: PpIX could inhibit tumor cell proliferation by induction of DNA damage and cell cycle arrest in the S phase.

  17. The cell cycle of the planctomycete Gemmata obscuriglobus with respect to cell compartmentalization

    Directory of Open Access Journals (Sweden)

    Fuerst John A

    2009-01-01

    well as DNA confirmed the behaviour of the nucleoid and nucleoid envelope during cell division. Electron microscopy of cryosubstituted cells confirmed deductions from light microscopy concerning nucleoid presence in relation to the stage of budding, and showed that the nucleoid was observed to occur in both mother and bud cells only at later budding stages. It further suggested that nucleoid envelope formed only after the nucleoid was translocated into the bud, since envelopes only appeared in more mature buds, while naked nucleoids occurred in smaller buds. Nucleoid envelope appeared to originate from the intracytoplasmic membranes (ICM of both mother cell and bud. There was always a connecting passage between mother cell and bud during the budding process until separation of the two cells. The division cycle of the nucleated planctomycete G. obscuriglobus appears to be a complex process in which chromosomal DNA is transported to the daughter cell bud after initial formation of the bud, and this can be performed repeatedly by a single mother cell. Conclusion The division cycle of the nucleated planctomycete G. obscuriglobus is a complex process in which chromosomal nucleoid DNA is transported to the daughter cell bud after initial formation of a bud without nucleoid. The new bud nucleoid is initially naked and not surrounded by membrane, but eventually acquires a complete nucleoid envelope consisting of two closely apposed membranes as occurs in the mother cell. The membranes of the new nucleoid envelope surrounding the bud nucleoid are derived from intracytoplasmic membranes of both the mother cell and the bud. The cell division of G. obscuriglobus displays some unique features not known in cells of either prokaryotes or eukaryotes.

  18. The timing of T cell priming and cycling

    Directory of Open Access Journals (Sweden)

    Reinhard eObst

    2015-11-01

    Full Text Available The proliferation of specific lymphocytes is the central tenet of the clonal selection paradigm. Antigen recognition by T cells triggers a series of events that produces expanded clones of differentiated effector cells. TCR signaling events are detectable within seconds and minutes and are likely to continue for hours and days in vivo. Here, I review the work done on the importance of TCR signals in the later part of the expansion phase of the primary T cell response, primarily regarding the regulation of the cell cycle in CD4+ and CD8+ cells. The results suggest a degree of programming by early signals for effector differentiation, particularly in the CD8+ T cell compartment, with optimal expansion supported by persistent antigen presentation later on. Differences to CD4+ T cell expansion and new avenues towards a molecular understanding of cell cycle regulation in lymphocytes are discussed.

  19. The Dynamical Mechanisms of the Cell Cycle Size Checkpoint

    International Nuclear Information System (INIS)

    Feng Shi-Fu; Yang Ling; Yan Jie; Liu Zeng-Rong

    2012-01-01

    Cell division must be tightly coupled to cell growth in order to maintain cell size, whereas the mechanisms of how initialization of mitosis is regulated by cell size remain to be elucidated. We develop a mathematical model of the cell cycle, which incorporates cell growth to investigate the dynamical properties of the size checkpoint in embryos of Xenopus laevis. We show that the size checkpoint is naturally raised from a saddle-node bifurcation, and in a mutant case, the cell loses its size control ability due to the loss of this saddle-node point

  20. BENZO[a]PYRENE DIOL EPOXIDE PERTURBATION OF CELL CYCLE KINETICS OF SYNCHRONIZED MOUSE LIVER EPITHELIAL CELLS

    Energy Technology Data Exchange (ETDEWEB)

    Pearlman, A.L.; Navsky, B.N.; Bartholomew, J.C

    1980-07-01

    A cell cycle synchronization system is described for the analysis of the perturbation of cell cycle kinetics and the cycle-phase specificity of chemicals and other agents. We used the system to study the effects of ({+-})r-7, t-8-dihydroxy-t-9, 10-oxy-7,8,9,10-tetrahydrobenzo[a]pyrene (BaP diol epoxide) upon the cell cycle of mouse liver epithelial cells(NMuLi). BaP diol epoxide(0.6 uM) was added to replated cultures of NMuLi cells that had been synchronized in various stages of the cell cycle by centrifugal elutriation. DNA histograms were obtained by flow cytometry as a function of time after replating. The data were analyzed by a computer modeling routine and reduced to a few graphs illustrating the 'net effects' of the BaP diol epoxide relative to controls. BaP diol epoxide slowed S-phase traversal in all samples relative to their respective control. Traversal through G{sub 2}M was also slowed by at least 50%. BaP diol epoxide had no apparent effect upon G{sub 1} traversal by cycling cells, but delayed the recruitment of quiescent G{sub 0} cells by about 2 hrs. The methods described constitute a powerful new approach for probing the cell cycle effects of a wide variety of agents. The present system appears to be extremely sensitive and capable of characterizing the action of agents on each phase of the cell cycle. The methods are automatable and would allow for the assay and possible differential characterization of mutagens and carcinogens.

  1. Induction of apoptosis and antiproliferative activity of naringenin in human epidermoid carcinoma cell through ROS generation and cell cycle arrest.

    Directory of Open Access Journals (Sweden)

    Md Sultan Ahamad

    Full Text Available A natural predominant flavanone naringenin, especially abundant in citrus fruits, has a wide range of pharmacological activities. The search for antiproliferative agents that reduce skin carcinoma is a task of great importance. The objective of this study was to analyze the anti-proliferative and apoptotic mechanism of naringenin using MTT assay, DNA fragmentation, nuclear condensation, change in mitochondrial membrane potential, cell cycle kinetics and caspase-3 as biomarkers and to investigate the ability to induce reactive oxygen species (ROS initiating apoptotic cascade in human epidermoid carcinoma A431 cells. Results showed that naringenin exposure significantly reduced the cell viability of A431 cells (p<0.01 with a concomitant increase in nuclear condensation and DNA fragmentation in a dose dependent manner. The intracellular ROS generation assay showed statistically significant (p<0.001 dose-related increment in ROS production for naringenin. It also caused naringenin-mediated epidermoid carcinoma apoptosis by inducing mitochondrial depolarization. Cell cycle study showed that naringenin induced cell cycle arrest in G0/G1 phase of cell cycle and caspase-3 analysis revealed a dose dependent increment in caspase-3 activity which led to cell apoptosis. This study confirms the efficacy of naringenin that lead to cell death in epidermoid carcinoma cells via inducing ROS generation, mitochondrial depolarization, nuclear condensation, DNA fragmentation, cell cycle arrest in G0/G1 phase and caspase-3 activation.

  2. Cell cycles and proliferation patterns in Haematococcus pluvialis

    Science.gov (United States)

    Zhang, Chunhui; Liu, Jianguo; Zhang, Litao

    2017-09-01

    Most studies on Haematococcus pluvialis have been focused on cell growth and astaxanthin accumulation; far less attention has been paid to cell cycles and proliferation patterns. The purpose of this study was to clarify cell cycles and proliferation patterns in H. pluvialis microscopically using a camera and video recorder system. The complicated life history of H. pluvialis can be divided into two stages: the motile stage and the non-motile stage. All the cells can be classified into forms as follows: motile cell, nonmotile cell, zoospore and aplanospore. The main cell proliferation, both in the motile phase and non-motile phase in H. pluvialis, is by asexual reproduction. Under normal growth conditions, a motile cell usually produces two, sometimes four, and exceptionally eight zoospores. Under unfavorable conditions, the motile cell loses its flagella and transforms into a non-motile cell, and the non-motile cell usually produces 2, 4 or 8 aplanospores, and occasionally 20-32 aplanospores, which further develop into non-motile cells. Under suitable conditions, the non-motile cell is also able to release zoospores. The larger non-motile cells produce more than 16 zoospores, and the smaller ones produce 4 or 8 zoospores. Vegetative reproduction is by direct cell division in the motile phase and by occasional cell budding in the non-motile phase. There is, as yet, no convincing direct evidence for sexual reproduction.

  3. Effect of sodium butyrate on cell proliferation and cell cycle in porcine intestinal epithelial (IPEC-J2) cells.

    Science.gov (United States)

    Qiu, Yueqin; Ma, Xianyong; Yang, Xuefen; Wang, Li; Jiang, Zongyong

    2017-04-01

    Conflicting results have been reported that butyrate in normal piglets leads either to an increase or to a decrease of jejunal villus length, implying a possible effect on the proliferation of enterocytes. No definitive study was found for the biological effects of butyrate in porcine jejunal epithelial cells. The present study used IPEC-J2 cells, a non-transformed jejunal epithelial line to evaluate the direct effects of sodium butyrate on cell proliferation, cell cycle regulation, and apoptosis. Low concentrations (0.5 and 1 mM) of butyrate had no effect on cell proliferation. However, at 5 and 10 mM, sodium butyrate significantly decreased cell viability, accompanied by reduced levels of p-mTOR and PCNA protein. Sodium butyrate, in a dose-dependent manner, induced cell cycle arrest in G0/G1 phase and reduced the numbers of cells in S phase. In addition, relative expression of p21, p27, and pro-apoptosis bak genes, and protein levels of p21Waf1/Cip1, p27Kip1, cyclinD3, CDK4, and Cleave-caspase3 were increased by higher concentrations of sodium butyrate (1, 5, 10 mM), and the levels of cyclinD1 and CDK6 were reduced by 5 and 10 mM butyrate. Butyrate increased the phosphorylated form of the signaling molecule p38 and phosphorylated JNK. In conclusion, the present in vitro study indicated that sodium butyrate inhibited the proliferation of IPEC-J2 cells by inducing cell cycle arrest in the G0/G1 phase of cell cycles and by increasing apoptosis at high concentrations.

  4. Metformin inhibits cell cycle progression of B-cell chronic lymphocytic leukemia cells

    Science.gov (United States)

    Bruno, Silvia; Ledda, Bernardetta; Tenca, Claudya; Ravera, Silvia; Orengo, Anna Maria; Mazzarello, Andrea Nicola; Pesenti, Elisa; Casciaro, Salvatore; Racchi, Omar; Ghiotto, Fabio; Marini, Cecilia; Sambuceti, Gianmario; DeCensi, Andrea; Fais, Franco

    2015-01-01

    B-cell chronic lymphocytic leukemia (CLL) was believed to result from clonal accumulation of resting apoptosis-resistant malignant B lymphocytes. However, it became increasingly clear that CLL cells undergo, during their life, iterative cycles of re-activation and subsequent clonal expansion. Drugs interfering with CLL cell cycle entry would be greatly beneficial in the treatment of this disease. 1, 1-Dimethylbiguanide hydrochloride (metformin), the most widely prescribed oral hypoglycemic agent, inexpensive and well tolerated, has recently received increased attention for its potential antitumor activity. We wondered whether metformin has apoptotic and anti-proliferative activity on leukemic cells derived from CLL patients. Metformin was administered in vitro either to quiescent cells or during CLL cell activation stimuli, provided by classical co-culturing with CD40L-expressing fibroblasts. At doses that were totally ineffective on normal lymphocytes, metformin induced apoptosis of quiescent CLL cells and inhibition of cell cycle entry when CLL were stimulated by CD40-CD40L ligation. This cytostatic effect was accompanied by decreased expression of survival- and proliferation-associated proteins, inhibition of signaling pathways involved in CLL disease progression and decreased intracellular glucose available for glycolysis. In drug combination experiments, metformin lowered the apoptotic threshold and potentiated the cytotoxic effects of classical and novel antitumor molecules. Our results indicate that, while CLL cells after stimulation are in the process of building their full survival and cycling armamentarium, the presence of metformin affects this process. PMID:26265439

  5. Age-related decrements in cycling and running performance ...

    African Journals Online (AJOL)

    South African Journal of Sports Medicine ... This study examined age-related decrements in athletic performance during running and cycling activities. ... These findings establish a trend that there is 'accelerated' aging during running which can perhaps be attributed to the increased weight-bearing stress on the muscles ...

  6. Albumin Suppresses Human Hepatocellular Carcinoma Proliferation and the Cell Cycle

    Directory of Open Access Journals (Sweden)

    Shunsuke Nojiri

    2014-03-01

    Full Text Available Many investigations have revealed that a low recurrence rate of hepatocellular carcinoma (HCC is associated with high serum albumin levels in patients; therefore, high levels of serum albumin are a major indicator of a favorable prognosis. However, the mechanism inhibiting the proliferation of HCC has not yet been elucidated, so we investigated the effect of serum albumin on HCC cell proliferation. Hep3B was cultured in MEM with no serum or containing 5 g/dL human albumin. As control samples, Prionex was added to generate the same osmotic pressure as albumin. After 24-h incubation, the expressions of α-fetoprotein (AFP, p53, p21, and p57 were evaluated with real-time PCR using total RNA extracted from the liver. Protein expressions and the phosphorylation of Rb (retinoblastoma were determined by Western blot analysis using total protein extracted from the liver. For flow cytometric analysis of the cell cycle, FACS analysis was performed. The percentages of cell cycle distribution were evaluated by PI staining, and all samples were analyzed employing FACScalibur (BD with appropriate software (ModFit LT; BD. The cell proliferation assay was performed by counting cells with using a Scepter handy automated cell counter (Millipore. The mRNA levels of AFP relative to Alb(−: Alb(−, Alb(+, and Prionex, were 1, 0.7 ± 0.2 (p < 0.001 for Alb(−, and 1 ± 0.3, respectively. The mRNA levels of p21 were 1, 1.58 ± 0.4 (p = 0.007 for Alb(− and p = 0.004 for Prionex, and 0.8 ± 0.2, respectively. The mRNA levels of p57 were 1, 4.4 ± 1.4 (p = 0.002 for Alb(− and Prionex, and 1.0 ± 0.1, respectively. The protein expression levels of Rb were similar in all culture media. The phosphorylation of P807/811 and P780 of Rb protein was reduced in Alb(+. More cells in the G0/G1 phase and fewer cells in S and G2/M phases were obtained in Alb(+ than in Alb(− (G0/G1: 60.9%, 67.7%, 61.5%; G2/M: 16.5%, 13.1%, 15.6%; S: 22.6%, 19.2%, 23.0%, Alb(−, Alb

  7. Estradiol partially recapitulates murine pituitary cell cycle response to pregnancy.

    Science.gov (United States)

    Toledano, Yoel; Zonis, Svetlana; Ren, Song-Guang; Wawrowsky, Kolja; Chesnokova, Vera; Melmed, Shlomo

    2012-10-01

    Because pregnancy and estrogens both induce pituitary lactotroph hyperplasia, we assessed the expression of pituitary cell cycle regulators in two models of murine pituitary hyperplasia. Female mice were assessed during nonpregnancy, pregnancy, day of delivery, and postpartum. We also implanted estradiol (E(2)) pellets in female mice and studied them for 2.5 months. Pituitary weight in female mice increased 2-fold after E(2) administration and 1.4-fold at day of delivery, compared with placebo-treated or nonpregnant females. Pituitary proliferation, as assessed by proliferating cell nuclear antigen and/or Ki-67 staining, increased dramatically during both mid-late pregnancy and E(2) administration, and lactotroph hyperplasia was also observed. Pregnancy induced pituitary cell cycle proliferative and inhibitory responses at the G(1)/S checkpoint. Differential cell cycle regulator expression included cyclin-dependent kinase inhibitors, p21(Cip1), p27(Kip1), and cyclin D1. Pituitary cell cycle responses to E(2) administration partially recapitulated those effects observed at mid-late pregnancy, coincident with elevated circulating mouse E(2), including increased expression of proliferating cell nuclear antigen, Ki-67, p15(INK4b), and p21(Cip1). Nuclear localization of pituitary p21(Cip1) was demonstrated at mid-late pregnancy but not during E(2) administration, suggesting a cell cycle inhibitory role for p21(Cip1) in pregnancy, yet a possible proproliferative role during E(2) administration. Most observed cell cycle protein alterations were reversed postpartum. Murine pituitary meets the demand for prolactin during lactation associated with induction of both cell proliferative and inhibitory pathways, mediated, at least partially, by estradiol.

  8. Sensitivity to radiation and cycle-active drugs as a function of stem cell compartment repletion

    International Nuclear Information System (INIS)

    Degowin, R.L.; Gibson, D.P.

    1976-01-01

    We have studied the sensitivity of normal mouse hemopoietic tissue to radiation and cycle-active drugs in relation to stem cell compartment repletion. Recovery of erythropoiesis in endogenous spleen colonies, blood reticulocytes, and 30-day survivals were determined in mice after an initial large dose of partial-body irradiation. We found that the normal stem cell compartment is more sensitive to cycle-independent modes of therapy, like radiation and cyclophosphamide, than it is to cycle-active agents like cytosine arabinoside and methotrexate. The depleted stem cell compartment exhibits marked sensitivity to cycle-independent agents but less to cycle-active agents, which, however, suppress its recovery more than they do the normal. The overshoot phase of recovery is relatively resistant to either cycle-independent or cycle-active agents. A reticulocytosis following a reticulocytopenia signals the overshoot phase of stem cell compartment recovery and relatively increased resistance. These findings may prove useful in designing chemotherapy regimens and in anticipating marrow recovery in planning for supportive care in patients with neoplastic disease

  9. Cell cycle kinetic analysis of colorectal neoplasms using a new automated immunohistochemistry-based cell cycle detection method.

    Science.gov (United States)

    Tomono, Ayako; Itoh, Tomoo; Yanagita, Emmy; Imagawa, Naoko; Kakeji, Yoshihiro

    2015-01-01

    We have recently developed a new method called the immunohistochemistry-based cell cycle detection (iCCD), which allows the determination of cell cycle phases on a cell-by-cell basis. This automated procedure can be performed on tissue sections and involves triple immunostaining for geminin, cdt1, and γ H2A.X, which are nuclear proteins expressed sequentially, with a few overlaps, during the cell cycle. In the current study, we applied this technique to resected specimens of colorectal neoplasm to determine the usefulness of iCCD for the pathological examination of colorectal cancers. We examined 141 cases of colorectal cancers. Normal mucosa and adenomas were analyzed as controls. In nonneoplastic mucosa, we observed a pattern of distribution of the cells positive for these cell cycle markers. Adenomas showed a slight distortion in this pattern, the geminin-positive cells, indicative of S/G2/M phase, were localized in the upper one-third region of the crypts. In neoplastic mucosa, the marker expression pattern was disorganized. Compared with normal mucosa, colorectal neoplasms showed an increased proportion of geminin-positive cells and decreased percentages of cdt1-positive cells (G1 phase). However, we did not find significant difference in the expression pattern between adenomas and carcinomas. Cellular proportions were correlated with clinicopathological parameters such as microscopic vascular invasion and pT stages. In cases of preoperative adjuvant therapy, the proportion of geminin-positive cells decreased, whereas that of γ H2A.X-positive cells (indicative of apoptosis/degeneration) increased significantly. We believe that this novel method can be applied to clinical samples to evaluate cell cycle kinetics and the effects of preoperative adjuvant therapy in colorectal cancers.

  10. The Thermodynamics of the Krebs Cycle and Related Compounds

    Science.gov (United States)

    Miller, Stanley L.; Smith-Magowan, David

    1990-07-01

    A survey is made of the enthalpies of formation, third law entropies and Gibbs energies available for Krebs cycle and related compounds. These include formate, acetate, succinate, fumarate, glycine, alanine, aspartate and glutamate. The potential of the NAD+/NADH couple is recalculated based on the ethanol/acetaldehyde and isopropanol/acetone equilibria. The reported enzyme catalyzed equilibrium constants of the Krebs cycle reactions are evaluated with estimated errors. These 28 equilibria form a network of reactions that is solved by a least squares regression procedure giving Gibbs energies of formation for 21 Krebs cycle and related compounds. They appear to be accurate to ±0.4 kJṡmol-1 for some compounds but ±1 kJṡmol-1 in less favorable cases. This procedure indicates which third law ΔfG and enzyme equilibria are inaccurate, and allows very accurate ΔfG to be determined for compounds related to the Krebs cycle by measuring enzyme equilibrium constants.

  11. Polyplex exposure inhibits cell cycle, increases inflammatory response, and can cause protein expression without cell division.

    Science.gov (United States)

    Matz, Rebecca L; Erickson, Blake; Vaidyanathan, Sriram; Kukowska-Latallo, Jolanta F; Baker, James R; Orr, Bradford G; Banaszak Holl, Mark M

    2013-04-01

    We sought to evaluate the relationship between cell division and protein expression when using commercial poly(ethylenimine) (PEI)-based polyplexes. The membrane dye PKH26 was used to assess cell division, and cyan fluorescent protein (CFP) was used to monitor protein expression. When analyzed at the whole population level, a greater number of cells divided than expressed protein, regardless of the level of protein expression observed, giving apparent consistency with the hypothesis that protein expression requires cells to pass through mitosis in order for the transgene to overcome the nuclear membrane. However, when the polyplex-exposed population was evaluated for the amount of division in the protein-expressing subpopulation, it was observed that substantial amounts of expression had occurred in the absence of division. Indeed, in HeLa S3 cells, this represented the majority of expressing cells. Of interest, the doubling time for both cell lines was slowed by ~2-fold upon exposure to polyplexes. This change was not altered by the origin of the plasmid DNA (pDNA) transgene promoter (cytomegalovirus (CMV) or elongation factor-1 alpha (EF1α)). Gene expression arrays in polyplex-exposed HeLa S3 cells showed upregulation of cell cycle arrest genes and downregulation of genes related to mitosis. Chemokine, interleukin, and toll-like receptor genes were also upregulated, suggesting activation of proinflammatory pathways. In summary, we find evidence that a cell division-independent expression pathway exists, and that polyplex exposure slows cell division and increases inflammatory response.

  12. Cell cycle regulation by the bacterial nucleoid.

    Science.gov (United States)

    Adams, David William; Wu, Ling Juan; Errington, Jeff

    2014-12-01

    Division site selection presents a fundamental challenge to all organisms. Bacterial cells are small and the chromosome (nucleoid) often fills most of the cell volume. Thus, in order to maximise fitness and avoid damaging the genetic material, cell division must be tightly co-ordinated with chromosome replication and segregation. To achieve this, bacteria employ a number of different mechanisms to regulate division site selection. One such mechanism, termed nucleoid occlusion, allows the nucleoid to protect itself by acting as a template for nucleoid occlusion factors, which prevent Z-ring assembly over the DNA. These factors are sequence-specific DNA-binding proteins that exploit the precise organisation of the nucleoid, allowing them to act as both spatial and temporal regulators of bacterial cell division. The identification of proteins responsible for this process has provided a molecular understanding of nucleoid occlusion but it has also prompted the realisation that substantial levels of redundancy exist between the diverse systems that bacteria employ to ensure that division occurs in the right place, at the right time.

  13. Molecular signature of cell cycle exit induced in human T lymphoblasts by IL-2 withdrawal

    Directory of Open Access Journals (Sweden)

    Pfeifer Aleksandra

    2009-06-01

    Full Text Available Abstract Background The molecular mechanisms of cell cycle exit are poorly understood. Studies on lymphocytes at cell cycle exit after growth factor deprivation have predominantly focused on the initiation of apoptosis. We aimed to study gene expression profile of primary and immortalised IL-2-dependent human T cells forced to exit the cell cycle by growth factor withdrawal, before apoptosis could be evidenced. Results By the Affymetrix microarrays HG-U133 2.0 Plus, 53 genes were distinguished as differentially expressed before and soon after IL-2 deprivation. Among those, PIM1, BCL2, IL-8, HBEGF, DUSP6, OSM, CISH, SOCS2, SOCS3, LIF and IL13 were down-regulated and RPS24, SQSTM1, TMEM1, LRRC8D, ECOP, YY1AP1, C1orf63, ASAH1, SLC25A46 and MIA3 were up-regulated. Genes linked to transcription, cell cycle, cell growth, proliferation and differentiation, cell adhesion, and immune functions were found to be overrepresented within the set of the differentially expressed genes. Conclusion Cell cycle exit of the growth factor-deprived T lymphocytes is characterised by a signature of differentially expressed genes. A coordinate repression of a set of genes known to be induced during T cell activation is observed. However, growth arrest following exit from the cell cycle is actively controlled by several up-regulated genes that enforce the non-dividing state. The identification of genes involved in cell cycle exit and quiescence provides new hints for further studies on the molecular mechanisms regulating the non-dividing state of a cell, the mechanisms closely related to cancer development and to many biological processes.

  14. Cyclebase 3.0: a multi-organism database on cell-cycle regulation and phenotypes.

    Science.gov (United States)

    Santos, Alberto; Wernersson, Rasmus; Jensen, Lars Juhl

    2015-01-01

    The eukaryotic cell division cycle is a highly regulated process that consists of a complex series of events and involves thousands of proteins. Researchers have studied the regulation of the cell cycle in several organisms, employing a wide range of high-throughput technologies, such as microarray-based mRNA expression profiling and quantitative proteomics. Due to its complexity, the cell cycle can also fail or otherwise change in many different ways if important genes are knocked out, which has been studied in several microscopy-based knockdown screens. The data from these many large-scale efforts are not easily accessed, analyzed and combined due to their inherent heterogeneity. To address this, we have created Cyclebase--available at http://www.cyclebase.org--an online database that allows users to easily visualize and download results from genome-wide cell-cycle-related experiments. In Cyclebase version 3.0, we have updated the content of the database to reflect changes to genome annotation, added new mRNA and protein expression data, and integrated cell-cycle phenotype information from high-content screens and model-organism databases. The new version of Cyclebase also features a new web interface, designed around an overview figure that summarizes all the cell-cycle-related data for a gene. © The Author(s) 2014. Published by Oxford University Press on behalf of Nucleic Acids Research.

  15. Establishment of human papillomavirus infection requires cell cycle progression.

    Directory of Open Access Journals (Sweden)

    Dohun Pyeon

    2009-02-01

    Full Text Available Human papillomaviruses (HPVs are DNA viruses associated with major human cancers. As such there is a strong interest in developing new means, such as vaccines and microbicides, to prevent HPV infections. Developing the latter requires a better understanding of the infectious life cycle of HPVs. The HPV infectious life cycle is closely linked to the differentiation state of the stratified epithelium it infects, with progeny virus only made in the terminally differentiating suprabasal compartment. It has long been recognized that HPV must first establish its infection within the basal layer of stratified epithelium, but why this is the case has not been understood. In part this restriction might reflect specificity of expression of entry receptors. However, this hypothesis could not fully explain the differentiation restriction of HPV infection, since many cell types can be infected with HPVs in monolayer cell culture. Here, we used chemical biology approaches to reveal that cell cycle progression through mitosis is critical for HPV infection. Using infectious HPV16 particles containing the intact viral genome, G1-synchronized human keratinocytes as hosts, and early viral gene expression as a readout for infection, we learned that the recipient cell must enter M phase (mitosis for HPV infection to take place. Late M phase inhibitors had no effect on infection, whereas G1, S, G2, and early M phase cell cycle inhibitors efficiently prevented infection. We conclude that host cells need to pass through early prophase for successful onset of transcription of the HPV encapsidated genes. These findings provide one reason why HPVs initially establish infections in the basal compartment of stratified epithelia. Only this compartment of the epithelium contains cells progressing through the cell cycle, and therefore it is only in these cells that HPVs can establish their infection. By defining a major condition for cell susceptibility to HPV infection, these

  16. A conserved cell growth cycle can account for the environmental stress responses of divergent eukaryotes

    Science.gov (United States)

    Slavov, Nikolai; Airoldi, Edoardo M.; van Oudenaarden, Alexander; Botstein, David

    2012-01-01

    The respiratory metabolic cycle in budding yeast (Saccharomyces cerevisiae) consists of two phases that are most simply defined phenomenologically: low oxygen consumption (LOC) and high oxygen consumption (HOC). Each phase is associated with the periodic expression of thousands of genes, producing oscillating patterns of gene expression found in synchronized cultures and in single cells of slowly growing unsynchronized cultures. Systematic variation in the durations of the HOC and LOC phases can account quantitatively for well-studied transcriptional responses to growth rate differences. Here we show that a similar mechanism—transitions from the HOC phase to the LOC phase—can account for much of the common environmental stress response (ESR) and for the cross-protection by a preliminary heat stress (or slow growth rate) to subsequent lethal heat stress. Similar to the budding yeast metabolic cycle, we suggest that a metabolic cycle, coupled in a similar way to the ESR, in the distantly related fission yeast, Schizosaccharomyces pombe, and in humans can explain gene expression and respiratory patterns observed in these eukaryotes. Although metabolic cycling is associated with the G0/G1 phase of the cell division cycle of slowly growing budding yeast, transcriptional cycling was detected in the G2 phase of the division cycle in fission yeast, consistent with the idea that respiratory metabolic cycling occurs during the phases of the cell division cycle associated with mass accumulation in these divergent eukaryotes. PMID:22456505

  17. Perspectives in cell cycle regulation: lessons from an anoxic vertebrate.

    Science.gov (United States)

    Biggar, Kyle K; Storey, Kenneth B

    2009-12-01

    The ability of an animal, normally dependent on aerobic respiration, to suspend breathing and enter an anoxic state for long term survival is clearly a fascinating feat, and has been the focus of numerous biochemical studies. When anoxia tolerant turtles are faced with periods of oxygen deprivation, numerous physiological and biochemical alterations take place in order to facilitate vital reductions in ATP consumption. Such strategies include reversible post-translational modifications as well as the implementation of translation and transcription controls facilitating metabolic depression. Although it is clear that anoxic survival relies on the suppression of ATP consuming processes, the state of the cell cycle in anoxia tolerant vertebrates remain elusive. Several anoxia tolerant invertebrate and embryonic vertebrate models display cell cycle arrest when presented with anoxic stress. Despite this, the cell cycle has not yet been characterized for anoxia tolerant turtles. Understanding how vertebrates respond to anoxia can have important clinical implications. Uncontrollable cellular proliferation and hypoxic tumor progression are inescapably linked in vertebrate tissues. Consequentially, the molecular mechanisms controlling these processes have profound clinical consequences. This review article will discuss the theory of cell cycle arrest in anoxic vertebrates and more specifically, the control of the retinoblastoma pathway, the molecular markers of cell cycle arrest, the activation of checkpoint kinases, and the possibility of translational controls implemented by microRNAs.

  18. Cell Division, a new open access online forum for and from the cell cycle community

    Directory of Open Access Journals (Sweden)

    Kaldis Philipp

    2006-04-01

    Full Text Available Abstract Cell Division is a new, open access, peer-reviewed online journal that publishes cutting-edge articles, commentaries and reviews on all exciting aspects of cell cycle control in eukaryotes. A major goal of this new journal is to publish timely and significant studies on the aberrations of the cell cycle network that occur in cancer and other diseases.

  19. Cell-cycle-dependent efficacy of photodynamic therapy with ATX-S10(Na).

    Science.gov (United States)

    Sano, Munetaka; Furuta, Takahisa; Takahira, Kenichiro; Kajimura, Masayoshi; Hanai, Hiroyuki; Kohno, Eiji; Hirano, Toru; Hishida, Akira

    2005-01-01

    Photodynamic therapy (PDT) is a useful strategy for treating various cancers. Details of the mechanisms of PDT have not been made clear yet. We intended to study the efficacy of PDT in relation to the cell cycle. HeLa S3 cells were synchronized by the thymidine block method. Cells in different cell cycle phases after release were treated with the water-soluble photosensitizer, ATX-S10(Na). The cellular viability after PDT was determined by the MTT assay. Intracellular levels of ATX-S10(Na) in different cell cycle phases were also determined. We found that cells in the S and G(2)/M phases were hypersensitive to PDT with ATX-S10(Na) in comparison with those in the G(1) phase, and that cellular levels of ATX-S10(Na) were increased in cells in the S and G(2)/M phases compared to those in the G(1) phase. We conclude that cellular ATX-S10(Na) levels differ among the different cell cycle phases, which is associated with the cell-cycle-dependent efficacy of PDT with ATX-S10(Na).

  20. Expression of cell cycle proteins in male breast carcinoma

    Directory of Open Access Journals (Sweden)

    Senger Jenna-Lynn

    2010-02-01

    Full Text Available Abstract Introduction Male breast cancer (MBC is a rare, yet potentially aggressive disease. Although literature regarding female breast cancer (FBC is extensive, little is known about the etiopathogenesis of male breast cancer. Studies from our laboratory show that MBCs have a distinct immunophenotypic profile, suggesting that the etiopathogenesis of MBC is different from FBCs. The aim of this study was to evaluate and correlate the immunohistochemical expression of cell cycle proteins in male breast carcinoma to significant clinico-biological endpoints. Methods 75 cases of MBC were identified using the records of the Saskatchewan Cancer Agency over 26 years (1970-1996. Cases were reviewed and analyzed for the immunohistochemical expression of PCNA, Ki67, p27, p16, p57, p21, cyclin-D1 and c-myc and correlated to clinico-biological endpoints of tumor size, node status, stage of the disease, and disease free survival (DFS. Results Decreased DFS was observed in the majority of tumors that overexpressed PCNA (98%, p = 0.004. The overexpression of PCNA was inversely correlated to the expression of Ki67 which was predominantly negative (78.3%. Cyclin D1 was overexpressed in 83.7% of cases. Cyclin D1 positive tumors were smaller than 2 cm (55.6%, p = 0.005, had a low incidence of lymph node metastasis (38.2%, p = 0.04 and were associated with increased DFS of >150 months (p = 0.04. Overexpression of c-myc (90% was linked with a higher incidence of node negativity (58.3%, p = 0.006 and increased DFS (p = 0.04. p27 over expression was associated with decreased lymph node metastasis (p = 0.04. P21 and p57 positive tumors were related to decreased DFS (p = 0.04. Though p16 was overexpressed in 76.6%, this did not reach statistical significance with DFS (p = 0.06 or nodal status (p = 0.07. Conclusion Aberrant cell cycle protein expression supports our view that these are important pathways involved in the etiopathogenesis of MBC. Tumors with overexpression

  1. Regulation of apoptosis and cell cycle in irradiated mouse brain

    Energy Technology Data Exchange (ETDEWEB)

    Oh, Won Yong; Song, Mi Hee; Hung, Eun Ji; Seong, Jin Sil; Suh, Chang Ok [College of Medicine, Yonsei Univ., Seoul (Korea, Republic of)

    2001-06-01

    To investigate the regulation of apoptosis and cell cycle in mouse brain irradiation. 8-week old male mice, C57B 1/6J were given whole body {gamma} -radiation with a single dose of 25 Gy using Cobalt 60 irradiator. At different times 1, 2, 4, 8 and 24hr after irradiation, mice were killed and brain tissues were collected. Apoptotic cells were scored by TUNEL assay. Expression of p53, Bcl-2, and Bax and cell cycle regulating molecules; cyclins BI, D1, E and cdk2, cdk4, p34{sup cdc2} were analysed by Western blotting. Cell cycle was analysed by flow cytometry. The peak of radiation induced apoptosis is shown at 8 hour after radiation. With a single 25 Gy irradiation, the peak of apoptotic index in C57B1/6J is 24.0{+-}0.25 (p<0.05) at 8 hour after radiation. Radiation upregulated the expression of p53/tubulin, Bax/tubulin, and Bcl-2/tubulin with 1.3, 1.1 and 1.45 fold increase, respectively were shown at the peak level at 8 hour after radiation. The levels of cell cycle regulating molecules after radiation are not changed significantly except cyclin D1 with 1.3 fold increase. Fractions of Go-G 1, G2-M and S phase in the cell cycle does not specific changes by time. In mouse brain tissue, radiation induced apoptosis is particularly shown in a specific area, subependyma. These results and lack of radiation induced changes in cell cycle offer better understanding of radiation response of normal brain tissue.

  2. Drug-Free Approach To Study the Unusual Cell Cycle of Giardia intestinalis

    Science.gov (United States)

    Horlock-Roberts, Kathleen; Reaume, Chase; Dayer, Guillem; Ouellet, Christine; Cook, Nicholas

    2017-01-01

    ABSTRACT Giardia intestinalis is a protozoan parasite that causes giardiasis, a form of severe and infectious diarrhea. Despite the importance of the cell cycle in the control of proliferation and differentiation during a giardia infection, it has been difficult to study this process due to the absence of a synchronization procedure that would not induce cellular damage resulting in artifacts. We utilized counterflow centrifugal elutriation (CCE), a size-based separation technique, to successfully obtain fractions of giardia cultures enriched in G1, S, and G2. Unlike drug-induced synchronization of giardia cultures, CCE did not induce double-stranded DNA damage or endoreplication. We observed increases in the appearance and size of the median body in the cells from elutriation fractions corresponding to the progression of the cell cycle from early G1 to late G2. Consequently, CCE could be used to examine the dynamics of the median body and other structures and organelles in the giardia cell cycle. For the cell cycle gene expression studies, the actin-related gene was identified by the program geNorm as the most suitable normalizer for reverse transcription-quantitative PCR (RT-qPCR) analysis of the CCE samples. Ten of 11 suspected cell cycle-regulated genes in the CCE fractions have expression profiles in giardia that resemble those of higher eukaryotes. However, the RNA levels of these genes during the cell cycle differ less than 4-fold to 5-fold, which might indicate that large changes in gene expression are not required by giardia to regulate the cell cycle. IMPORTANCE Giardias are among the most commonly reported intestinal protozoa in the world, with infections seen in humans and over 40 species of animals. The life cycle of giardia alternates between the motile trophozoite and the infectious cyst. The regulation of the cell cycle controls the proliferation of giardia trophozoites during an active infection and contains the restriction point for the

  3. Identification of a novel EGF-sensitive cell cycle checkpoint

    International Nuclear Information System (INIS)

    Walker, Francesca; Zhang Huihua; Burgess, Antony W.

    2007-01-01

    The site of action of growth factors on mammalian cell cycle has been assigned to the boundary between the G1 and S phases. We show here that Epidermal Growth Factor (EGF) is also required for mitosis. BaF/3 cells expressing the EGFR (BaF/wtEGFR) synthesize DNA in response to EGF, but arrest in S-phase. We have generated a cell line (BaF/ERX) with defective downregulation of the EGFR and sustained activation of EGFR signalling pathways: these cells undergo mitosis in an EGF-dependent manner. The transit of BaF/ERX cells through G2/M strictly requires activation of EGFR and is abolished by AG1478. This phenotype is mimicked by co-expression of ErbB2 in BaF/wtEGFR cells, and abolished by inhibition of the EGFR kinase, suggesting that sustained signalling of the EGFR, through impaired downregulation of the EGFR or heterodimerization, is required for completion of the cycle. We have confirmed the role of EGFR signalling in the G2/M phase of the cell cycle using a human tumor cell line which overexpresses the EGFR and is dependent on EGFR signalling for growth. These findings unmask an EGF-sensitive checkpoint, helping to understand the link between sustained EGFR signalling, proliferation and the acquisition of a radioresistant phenotype in cancer cells

  4. Cell Death and Cell Cycle Arrest of Silene latifolia Stamens and Pistils After Microbotryum lychnidis-dioicae Infection.

    Science.gov (United States)

    Kawamoto, Hiroki; Yamanaka, Kaori; Koizumi, Ayako; Hirata, Aiko; Kawano, Shigeyuki

    2017-02-01

    Mechanisms of suppression of pistil primordia in male flowers and of stamen primordia in female flowers differ in diclinous plants. In this study, we investigated how cell death and cell cycle arrest are related to flower organ formation in Silene latifolia. Using in situ hybridization and a TUNEL (terminal deoxynucleotidyl transferase dUTP nick end labeling) assay, we detected both cell cycle arrest and cell death in suppressed stamens of female flowers and suppressed pistils of male flowers in S. latifolia. In female flowers infected with Microbotryum lychnidis-dioicae, developmental suppression of stamens is released, and cell cycle arrest and cell death do not occur. Smut spores are formed in S. latifolia anthers infected with M. lychnidis-dioicae, followed by cell death in the endothelium, middle layer, tapetal cells and pollen mother cells. Cell death is difficult to detect using a fluorescein isothiocyanate-labeled TUNEL assay due to strong autofluorescence in the anther. We therefore combined a TUNEL assay in an infrared region with transmission electron microscopy to detect cell death in anthers. We show that following infection by M. lychnidis-dioicae, a TUNEL signal was not detected in the endothelium, middle layer or pollen mother cells, and cell death with outflow of cell contents, including the nucleoplast, was observed in tapetal cells. © The Author 2016. Published by Oxford University Press on behalf of Japanese Society of Plant Physiologists. All rights reserved. For permissions, please email: journals.permissions@oup.com.

  5. Canthin-6-one induces cell death, cell cycle arrest and differentiation in human myeloid leukemia cells.

    Science.gov (United States)

    Vieira Torquato, Heron F; Ribeiro-Filho, Antonio C; Buri, Marcus V; Araújo Júnior, Roberto T; Pimenta, Renata; de Oliveira, José Salvador R; Filho, Valdir C; Macho, Antonio; Paredes-Gamero, Edgar J; de Oliveira Martins, Domingos T

    2017-04-01

    Canthin-6-one is a natural product isolated from various plant genera and from fungi with potential antitumor activity. In the present study, we evaluate the antitumor effects of canthin-6-one in human myeloid leukemia lineages. Kasumi-1 lineage was used as a model for acute myeloid leukemia. Cells were treated with canthin-6-one and cell death, cell cycle and differentiation were evaluated in both total cells (Lin + ) and leukemia stem cell population (CD34 + CD38 - Lin -/low ). Among the human lineages tested, Kasumi-1 was the most sensitive to canthin-6-one. Canthin-6-one induced cell death with apoptotic (caspase activation, decrease of mitochondrial potential) and necrotic (lysosomal permeabilization, double labeling of annexin V/propidium iodide) characteristics. Moreover, canthin-6-one induced cell cycle arrest at G 0 /G 1 (7μM) and G 2 (45μM) evidenced by DNA content, BrdU incorporation and cyclin B1/histone 3 quantification. Canthin-6-one also promoted differentiation of Kasumi-1, evidenced by an increase in the expression of myeloid markers (CD11b and CD15) and the transcription factor PU.1. Furthermore, a reduction of the leukemic stem cell population and clonogenic capability of stem cells were observed. These results show that canthin-6-one can affect Kasumi-1 cells by promoting cell death, cell cycle arrest and cell differentiation depending on concentration used. Canthin-6-one presents an interesting cytotoxic activity against leukemic cells and represents a promising scaffold for the development of molecules for anti-leukemic applications, especially by its anti-leukemic stem cell activity. Copyright © 2017 Elsevier B.V. All rights reserved.

  6. Cell cycle phase specificity of putative cyclin-dependent kinase variants in synchronized alfalfa cells.

    Science.gov (United States)

    Magyar, Z; Mészáros, T; Miskolczi, P; Deák, M; Fehér, A; Brown, S; Kondorosi, E; Athanasiadis, A; Pongor, S; Bilgin, M; Bakó, L; Koncz, C; Dudits, D

    1997-02-01

    The eukaryotic cell division cycle is coordinated by cyclin-dependent kinases (CDKs), represented by a single major serine/threonine kinase in yeasts (Cdc2/CDC28) and a family of kinases (CDK1 to CDK8) in human cells. Previously, two cdc2 homologs, cdc2MsA and cdc2MsB, have been identified in alfalfa (Medicago sativa). By isolating cDNAs using a cdc2MsA probe, we demonstrate here that at least four additional cdc2 homologous genes are expressed in the tetraploid alfalfa. Proteins encoded by the new cdc2MsC to cdc2MsF cDNAs share the characteristic functional domains of CDKs with the conserved and plant-specific sequence elements. Transcripts from cdc2MsA, cdc2MsB, cdc2MsC, and cdc2MsE genes are synthesized throughout the cell cycle, whereas the amounts of cdc2MsD and cdc2MsF mRNAs peak during G2-to-M phases. The translation of Cdc2MsA/B, Cdc2MsD, and Cdc2MsF proteins follows the pattern of transcript accumulation. The multiplicity of kinase complexes with cell cycle phase-dependent activities was revealed by in vitro phosphorylation experiments. Proteins bound to p13suc1-Sepharose or immunoprecipitated with Cdc2MsA/B antibodies from cells at G1-to-S and G2-to-M phase boundaries showed elevated kinase activities. the Cdc2MsF antibodies separated a G2-to-M phase-related kinase complex. Detection of histone H1 phosphorylation activities in fractions immunoprecipitated with antimitotic cyclin (CyclinMs2) antibodies from G2-to-M phase cells indicates the complex formation between this cyclin and a kinase partner in alfalfa. The observed fluctuation of transcript levels, amounts, and activities of kinases in different cell cycle phases reflects a multilevel regulatory system during cell cycle progression in plants.

  7. Pyridine nucleotide cycling and control of intracellular redox state in relation to poly (ADP-ribose) polymerase activity and nuclear localization of glutathione during exponential growth of Arabidopsis cells in culture.

    Science.gov (United States)

    Pellny, Till K; Locato, Vittoria; Vivancos, Pedro Diaz; Markovic, Jelena; De Gara, Laura; Pallardó, Federico V; Foyer, Christine H

    2009-05-01

    Pyridine nucleotides, ascorbate and glutathione are major redox metabolites in plant cells, with specific roles in cellular redox homeostasis and the regulation of the cell cycle. However, the regulation of these metabolite pools during exponential growth and their precise functions in the cell cycle remain to be characterized. The present analysis of the abundance of ascorbate, glutathione, and pyridine nucleotides during exponential growth of Arabidopsis cells in culture provides evidence for the differential regulation of each of these redox pools. Ascorbate was most abundant early in the growth cycle, but glutathione was low at this point. The cellular ascorbate to dehydroascorbate and reduced glutathione (GSH) to glutathione disulphide ratios were high and constant but the pyridine nucleotide pools were largely oxidized over the period of exponential growth and only became more reduced once growth had ceased. The glutathione pool increased in parallel with poly (ADP-ribose) polymerase (PARP) activities and with increases in the abundance of PARP1 and PARP2 mRNAs at a time of high cell cycle activity as indicated by transcriptome information. Marked changes in the intracellular partitioning of GSH between the cytoplasm and nucleus were observed. Extension of the exponential growth phase by dilution or changing the media led to increases in the glutathione and nicotinamide adenine dinucleotide, oxidized form (NAD)-plus-nicotinamide adenine dinucleotide, reduced form (NADH) pools and to higher NAD/NADH ratios but the nicotinamide adenine dinucleotide phosphate, oxidized form (NADP)-plus-nicotinamide adenine dinucleotide phosphate, reduced form (NADPH) pool sizes, and NAPD/NADPH ratios were much less affected. The ascorbate, glutathione, and pyridine nucleotide pools and PARP activity decreased before the exponential growth phase ended. We conclude that there are marked changes in intracellular redox state during the growth cycle but that redox homeostasis is

  8. Angular-dependent light scattering from cancer cells in different phases of the cell cycle.

    Science.gov (United States)

    Lin, Xiaogang; Wan, Nan; Weng, Lingdong; Zhou, Yong

    2017-10-10

    Cancer cells in different phases of the cell cycle result in significant differences in light scattering properties. In order to harvest cancer cells in particular phases of the cell cycle, we cultured cancer cells through the process of synchronization. Flow cytometric analysis was applied to check the results of cell synchronization and prepare for light scattering measurements. Angular-dependent light scattering measurements of cancer cells arrested in the G1, S, and G2 phases have been performed. Based on integral calculations for scattering intensities from 5° to 10° and from 110° to 150°, conclusions have been reached. Clearly, the sizes of the cancer cells in different phases of the cell cycle dominated the forward scatter. Accompanying the increase of cell size with the progression of the cell cycle, the forward scattering intensity also increased. Meanwhile, the DNA content of cancer cells in every phase of the cell cycle is responsible for light scattering at large scatter angles. The higher the DNA content of cancer cells was, the greater the positive effect on the high-scattering intensity. As expected, understanding the relationships between the light scattering from cancer cells and cell cycles will aid in the development of cancer diagnoses. Also, it may assist in the guidance of antineoplastic drugs clinically.

  9. Analysis of cell flow and cell loss following X-irradiation using sequential investigation of the total number of cells in the various parts of the cell cycle

    International Nuclear Information System (INIS)

    Skog, S.; Tribukait, B.

    1985-01-01

    The cell flow and cell loss of an in vivo growing Ehrlich ascites tumour were calculated by sequential estimation of changes in total number of cells in the cell cycle compartments. Normal growth was compared with the grossly disturbed cell flow evident after a 5 Gy X-irradiation. The doubling time of normal, exponentially growing cells was 24 hr. The generation time was 21 hr and the potential doubling time was 21 hr. Thus, the growth fraction was 1.0 and the cell loss rate about 0.5%/hr. Following irradiation, a transiently increased relative outflow rate from all cell cycle compartments was found at about 3 and 40 hr, and from S phase at 24 hr after irradiation. Increase in cell loss as well as non-viable cells was observed at 24 hr after irradiation at the time of release of the irradiation-induced G 2 blockage. The experiments show the applicability and limitations of cell flow and cell loss calculations by sequential analysis of the total number of cells in the various parts of the cell cycle. (author)

  10. Evolution of cell cycle control: same molecular machines, different regulation

    DEFF Research Database (Denmark)

    de Lichtenberg, Ulrik; Jensen, Thomas Skøt; Brunak, Søren

    2007-01-01

    or deactivated at specific stages during the cell cycle through a wide variety of mechanisms including transcriptional regulation, phosphorylation, subcellular translocation and targeted degradation. In a series of integrative analyses of different genome-scale data sets, we have studied how these different...... layers of regulation together control the activity of cell cycle complexes and how this regulation has evolved. The results show surprisingly poor conservation of both the transcriptional and the post-translation regulation of individual genes and proteins; however, the changes in one layer of regulation...... are often mirrored by changes in other layers, implying that independent layers of control coevolve. By taking a bird's eye view of the cell cycle, we demonstrate how the modular organization of cellular systems possesses a built-in flexibility, which allows evolution to find many different solutions...

  11. Evolution of cell cycle control: same molecular machines, different regulation

    DEFF Research Database (Denmark)

    de Lichtenberg, Ulrik; Jensen, Thomas Skøt; Brunak, Søren

    2007-01-01

    Decades of research has together with the availability of whole genomes made it clear that many of the core components involved in the cell cycle are conserved across eukaryotes, both functionally and structurally. These proteins are organized in complexes and modules that are activated...... or deactivated at specific stages during the cell cycle through a wide variety of mechanisms including transcriptional regulation, phosphorylation, subcellular translocation and targeted degradation. In a series of integrative analyses of different genome-scale data sets, we have studied how these different...... layers of regulation together control the activity of cell cycle complexes and how this regulation has evolved. The results show surprisingly poor conservation of both the transcriptional and the post-translation regulation of individual genes and proteins; however, the changes in one layer of regulation...

  12. Sepiapterin Reductase Mediates Chemical Redox Cycling in Lung Epithelial Cells*

    Science.gov (United States)

    Yang, Shaojun; Jan, Yi-Hua; Gray, Joshua P.; Mishin, Vladimir; Heck, Diane E.; Laskin, Debra L.; Laskin, Jeffrey D.

    2013-01-01

    In the lung, chemical redox cycling generates highly toxic reactive oxygen species that can cause alveolar inflammation and damage to the epithelium, as well as fibrosis. In this study, we identified a cytosolic NADPH-dependent redox cycling activity in mouse lung epithelial cells as sepiapterin reductase (SPR), an enzyme important for the biosynthesis of tetrahydrobiopterin. Human SPR was cloned and characterized. In addition to reducing sepiapterin, SPR mediated chemical redox cycling of bipyridinium herbicides and various quinones; this activity was greatest for 1,2-naphthoquinone followed by 9,10-phenanthrenequinone, 1,4-naphthoquinone, menadione, and 2,3-dimethyl-1,4-naphthoquinone. Whereas redox cycling chemicals inhibited sepiapterin reduction, sepiapterin had no effect on redox cycling. Additionally, inhibitors such as dicoumarol, N-acetylserotonin, and indomethacin blocked sepiapterin reduction, with no effect on redox cycling. Non-redox cycling quinones, including benzoquinone and phenylquinone, were competitive inhibitors of sepiapterin reduction but noncompetitive redox cycling inhibitors. Site-directed mutagenesis of the SPR C-terminal substrate-binding site (D257H) completely inhibited sepiapterin reduction but had minimal effects on redox cycling. These data indicate that SPR-mediated reduction of sepiapterin and redox cycling occur by distinct mechanisms. The identification of SPR as a key enzyme mediating chemical redox cycling suggests that it may be important in generating cytotoxic reactive oxygen species in the lung. This activity, together with inhibition of sepiapterin reduction by redox-active chemicals and consequent deficiencies in tetrahydrobiopterin, may contribute to tissue injury. PMID:23640889

  13. Modulations of cell cycle checkpoints during HCV associated disease

    Directory of Open Access Journals (Sweden)

    Jafri Wasim

    2009-08-01

    Full Text Available Abstract Background Impaired proliferation of hepatocytes has been reported in chronic Hepatitis C virus infection. Considering the fundamental role played by cell cycle proteins in controlling cell proliferation, altered regulation of these proteins could significantly contribute to HCV disease progression and subsequent hepatocellular carcinoma (HCC. This study aimed to identify the alterations in cell cycle genes expression with respect to early and advanced disease of chronic HCV infection. Methods Using freshly frozen liver biopsies, mRNA levels of 84 cell cycle genes in pooled RNA samples from patients with early or advanced fibrosis of chronic HCV infection were studied. To associate mRNA levels with respective protein levels, four genes (p27, p15, KNTC1 and MAD2L1 with significant changes in mRNA levels (> 2-fold, p-value Results In the early fibrosis group, increased mRNA levels of cell proliferation genes as well as cell cycle inhibitor genes were observed. In the advanced fibrosis group, DNA damage response genes were up-regulated while those associated with chromosomal stability were down-regulated. Increased expression of CDK inhibitor protein p27 was consistent with its mRNA level detected in early group while the same was found to be negatively associated with liver fibrosis. CDK inhibitor protein p15 was highly expressed in both early and advanced group, but showed no correlation with fibrosis. Among the mitotic checkpoint regulators, expression of KNTC1 was significantly reduced in advanced group while MAD2L1 showed a non-significant decrease. Conclusion Collectively these results are suggestive of a disrupted cell cycle regulation in HCV-infected liver. The information presented here highlights the potential of identified proteins as predictive factors to identify patients with high risk of cell transformation and HCC development.

  14. An apoptotic cell cycle mutant in Saccharomyces cerevisiae

    DEFF Research Database (Denmark)

    Villadsen, Ingrid

    1996-01-01

    The simple eukaryote Saccharomyces cerevisiae has proved to be a useful organism for elucidating the mechanisms that govern cell cycle progression in eukaryotic cells. The excellent in vivo system permits a cell cycle study using temperature sensitive mutants. In addition, it is possible to study...... many genes and gene products from higher eukaryotes in Saccharomyces cerevisiae because many genes and biological processes are homologous or similar in lower and in higher eukaryotes. The highly developed methods of genetics and molecular biology greatly facilitates studies of higher eukaryotic...... processes.Programmmed cell death with apoptosis plays a major role in development and homeostatis in most, if not all, animal cells. Apoptosis is a morphologically distinct form of death, that requires the activation of a highly regulated suicide program. Saccharomyces cerevisiae provides a new system...

  15. Does Arabidopsis thaliana DREAM of cell cycle control?

    Science.gov (United States)

    Fischer, Martin; DeCaprio, James A

    2015-08-04

    Strict temporal control of cell cycle gene expression is essential for all eukaryotes including animals and plants. DREAM complexes have been identified in worm, fly, and mammals, linking several distinct transcription factors to coordinate gene expression throughout the cell cycle. In this issue of The EMBO Journal, Kobayashi et al (2015) identify distinct activator and repressor complexes for genes expressed during the G2 and M phases in Arabidopsis that can be temporarily separated during proliferating and post‐mitotic stages of development. The complexes incorporate specific activator and repressor MYB and E2F transcription factors and indicate the possibility of the existence of multiple DREAM complexes in plants.

  16. Meta-analysis reveals conserved cell cycle transcriptional network across multiple human cell types.

    Science.gov (United States)

    Giotti, Bruno; Joshi, Anagha; Freeman, Tom C

    2017-01-05

    Cell division is central to the physiology and pathology of all eukaryotic organisms. The molecular machinery underpinning the cell cycle has been studied extensively in a number of species and core aspects of it have been found to be highly conserved. Similarly, the transcriptional changes associated with this pathway have been studied in different organisms and different cell types. In each case hundreds of genes have been reported to be regulated, however there seems to be little consensus in the genes identified across different studies. In a recent comparison of transcriptomic studies of the cell cycle in different human cell types, only 96 cell cycle genes were reported to be the same across all studies examined. Here we perform a systematic re-examination of published human cell cycle expression data by using a network-based approach to identify groups of genes with a similar expression profile and therefore function. Two clusters in particular, containing 298 transcripts, showed patterns of expression consistent with cell cycle occurrence across the four human cell types assessed. Our analysis shows that there is a far greater conservation of cell cycle-associated gene expression across human cell types than reported previously, which can be separated into two distinct transcriptional networks associated with the G 1 /S-S and G 2 -M phases of the cell cycle. This work also highlights the benefits of performing a re-analysis on combined datasets.

  17. Role of Kupffer Cells in Thioacetamide-Induced Cell Cycle Dysfunction

    Directory of Open Access Journals (Sweden)

    Mirandeli Bautista

    2011-09-01

    Full Text Available It is well known that gadolinium chloride (GD attenuates drug-induced hepatotoxicity by selectively inactivating Kupffer cells. In the present study the effect of GD in reference to cell cycle and postnecrotic liver regeneration induced by thioacetamide (TA in rats was studied. Two months male rats, intraveously pretreated with a single dose of GD (0.1 mmol/Kg, were intraperitoneally injected with TA (6.6 mmol/Kg. Samples of blood and liver were obtained from rats at 0, 12, 24, 48, 72 and 96 h following TA intoxication. Parameters related to liver damage were determined in blood. In order to evaluate the mechanisms involved in the post-necrotic regenerative state, the levels of cyclin D and cyclin E as well as protein p27 and Proliferating Cell Nuclear Antigen (PCNA were determined in liver extracts because of their roles in the control of cell cycle check-points. The results showed that GD significantly reduced the extent of necrosis. Noticeable changes were detected in the levels of cyclin D1, cyclin E, p27 and PCNA when compared to those induced by thioacetamide. Thus GD pre-treatment reduced TA-induced liver injury and accelerated the postnecrotic liver regeneration. These results demonstrate that Kupffer cells are involved in TA-induced liver and also in the postnecrotic proliferative liver states.

  18. High doses of bisphosphonates reduce osteoblast-like cell proliferation by arresting the cell cycle and inducing apoptosis.

    Science.gov (United States)

    Manzano-Moreno, Francisco Javier; Ramos-Torrecillas, Javier; De Luna-Bertos, Elvira; Ruiz, Concepción; García-Martínez, Olga

    2015-04-01

    The study objective was to evaluate the effect on osteoblast growth of high concentrations of three nitrogen-containing bisphosphonates (pamidronate, alendronate, and ibandronate) and one non-nitrogen-containing bisphosphonate (clodronate), using the MG-63 cell line as an osteoblast model, in order to determine the role of osteoblasts in bisphosphonate-related osteonecrosis of the jaw (BRONJ). Osteoblasts were incubated in culture medium with different doses of pamidronate, alendronate, ibandronate or clodronate. The proliferative capacity of the osteoblasts was determined by spectrophotometry (MTT-based) at 24 h of culture. Flow cytometry was used to determine the percentage of cells in each cell cycle phase (G0/G1, G2/M, and S) and to discriminate apoptotic cell death from necrotic cell death in the cell cycle at 24 h of treatment. All the bisphosphonates assayed produced a significant and dose-dependent reduction in MG-63 proliferation at the high doses assayed (10(-4) and 5 × 10(-5) M) in comparison with controls (p bisphosphonates significantly arrested the cell cycle in phase G0/G1 at doses of 10(-4) and 5 × 10(-5) M, increasing the percentage of cells in this phase (p bisphosphonates can reduce the proliferation of MG-63 osteoblast-like cells by arresting the cell cycle and inducing apoptosis/necrosis. Copyright © 2015 European Association for Cranio-Maxillo-Facial Surgery. Published by Elsevier Ltd. All rights reserved.

  19. Single-cell RNA-seq reveals changes in cell cycle and differentiation programs upon aging of hematopoietic stem cells

    Science.gov (United States)

    Kowalczyk, Monika S.; Tirosh, Itay; Heckl, Dirk; Rao, Tata Nageswara; Dixit, Atray; Haas, Brian J.; Schneider, Rebekka K.; Wagers, Amy J.; Ebert, Benjamin L.; Regev, Aviv

    2015-01-01

    Both intrinsic cell state changes and variations in the composition of stem cell populations have been implicated as contributors to aging. We used single-cell RNA-seq to dissect variability in hematopoietic stem cell (HSC) and hematopoietic progenitor cell populations from young and old mice from two strains. We found that cell cycle dominates the variability within each population and that there is a lower frequency of cells in the G1 phase among old compared with young long-term HSCs, suggesting that they traverse through G1 faster. Moreover, transcriptional changes in HSCs during aging are inversely related to those upon HSC differentiation, such that old short-term (ST) HSCs resemble young long-term (LT-HSCs), suggesting that they exist in a less differentiated state. Our results indicate both compositional changes and intrinsic, population-wide changes with age and are consistent with a model where a relationship between cell cycle progression and self-renewal versus differentiation of HSCs is affected by aging and may contribute to the functional decline of old HSCs. PMID:26430063

  20. The Design Space of the Embryonic Cell Cycle Oscillator.

    Science.gov (United States)

    Mattingly, Henry H; Sheintuch, Moshe; Shvartsman, Stanislav Y

    2017-08-08

    One of the main tasks in the analysis of models of biomolecular networks is to characterize the domain of the parameter space that corresponds to a specific behavior. Given the large number of parameters in most models, this is no trivial task. We use a model of the embryonic cell cycle to illustrate the approaches that can be used to characterize the domain of parameter space corresponding to limit cycle oscillations, a regime that coordinates periodic entry into and exit from mitosis. Our approach relies on geometric construction of bifurcation sets, numerical continuation, and random sampling of parameters. We delineate the multidimensional oscillatory domain and use it to quantify the robustness of periodic trajectories. Although some of our techniques explore the specific features of the chosen system, the general approach can be extended to other models of the cell cycle engine and other biomolecular networks. Copyright © 2017 Biophysical Society. Published by Elsevier Inc. All rights reserved.

  1. Cell cycle control by a minimal Cdk network.

    Directory of Open Access Journals (Sweden)

    Claude Gérard

    2015-02-01

    Full Text Available In present-day eukaryotes, the cell division cycle is controlled by a complex network of interacting proteins, including members of the cyclin and cyclin-dependent protein kinase (Cdk families, and the Anaphase Promoting Complex (APC. Successful progression through the cell cycle depends on precise, temporally ordered regulation of the functions of these proteins. In light of this complexity, it is surprising that in fission yeast, a minimal Cdk network consisting of a single cyclin-Cdk fusion protein can control DNA synthesis and mitosis in a manner that is indistinguishable from wild type. To improve our understanding of the cell cycle regulatory network, we built and analysed a mathematical model of the molecular interactions controlling the G1/S and G2/M transitions in these minimal cells. The model accounts for all observed properties of yeast strains operating with the fusion protein. Importantly, coupling the model's predictions with experimental analysis of alternative minimal cells, we uncover an explanation for the unexpected fact that elimination of inhibitory phosphorylation of Cdk is benign in these strains while it strongly affects normal cells. Furthermore, in the strain without inhibitory phosphorylation of the fusion protein, the distribution of cell size at division is unusually broad, an observation that is accounted for by stochastic simulations of the model. Our approach provides novel insights into the organization and quantitative regulation of wild type cell cycle progression. In particular, it leads us to propose a new mechanistic model for the phenomenon of mitotic catastrophe, relying on a combination of unregulated, multi-cyclin-dependent Cdk activities.

  2. Plant Characteristics of an Integrated Solid Oxide Fuel Cell Cycle and a Steam Cycle

    DEFF Research Database (Denmark)

    Rokni, Masoud

    2010-01-01

    hydrocarbons in an adiabatic steam reformer (ASR). The pre-treated fuel then entered to the anode side of the SOFC. The remaining fuels after the SOFC stacks entered a catalytic burner for further combusting. The burned gases from the burner were then used to produce steam for the Rankine cycle in a heat......Plant characteristics of a system containing a solid oxide fuel cell (SOFC) cycle on the top of a Rankine cycle were investigated. Natural gas (NG) was used as the fuel for the plant. A desulfurization reactor removes the sulfur content in the fuel, while a pre-reformer broke down the heavier...... and the pre-reformer reactor had no effect on the plant efficiency, which was also true when decreasing the anode temperature. However, increasing the cathode temperature had a significant effect on the plant efficiency. In addition, decreasing the SOFC utilization factor from 0.8 to 0.7, increases the plant...

  3. Increasing water cycle extremes in California and in relation to ENSO cycle under global warming.

    Science.gov (United States)

    Yoon, Jin-Ho; Wang, S-Y Simon; Gillies, Robert R; Kravitz, Ben; Hipps, Lawrence; Rasch, Philip J

    2015-10-21

    Since the winter of 2013-2014, California has experienced its most severe drought in recorded history, causing statewide water stress, severe economic loss and an extraordinary increase in wildfires. Identifying the effects of global warming on regional water cycle extremes, such as the ongoing drought in California, remains a challenge. Here we analyse large-ensemble and multi-model simulations that project the future of water cycle extremes in California as well as to understand those associations that pertain to changing climate oscillations under global warming. Both intense drought and excessive flooding are projected to increase by at least 50% towards the end of the twenty-first century; this projected increase in water cycle extremes is associated with a strengthened relation to El Niño and the Southern Oscillation (ENSO)--in particular, extreme El Niño and La Niña events that modulate California's climate not only through its warm and cold phases but also its precursor patterns.

  4. Increasing water cycle extremes in California and in relation to ENSO cycle under global warming

    Science.gov (United States)

    Yoon, Jin-Ho; Wang, S-Y Simon; Gillies, Robert R.; Kravitz, Ben; Hipps, Lawrence; Rasch, Philip J.

    2015-01-01

    Since the winter of 2013–2014, California has experienced its most severe drought in recorded history, causing statewide water stress, severe economic loss and an extraordinary increase in wildfires. Identifying the effects of global warming on regional water cycle extremes, such as the ongoing drought in California, remains a challenge. Here we analyse large-ensemble and multi-model simulations that project the future of water cycle extremes in California as well as to understand those associations that pertain to changing climate oscillations under global warming. Both intense drought and excessive flooding are projected to increase by at least 50% towards the end of the twenty-first century; this projected increase in water cycle extremes is associated with a strengthened relation to El Niño and the Southern Oscillation (ENSO)—in particular, extreme El Niño and La Niña events that modulate California's climate not only through its warm and cold phases but also its precursor patterns. PMID:26487088

  5. Eukaryotic checkpoints are absent in the cell division cycle of ...

    Indian Academy of Sciences (India)

    It has also been shown that although this organism contains sequence homologs of genes which are known to control the cell cycle of most eukaryotes, these genes may be structurally altered and their equivalent function yet to be demonstrated in amoeba. The available information suggests that surveillance mechanisms ...

  6. Cell-Cycle-Dependent Reconfiguration of the DNA Methylome during Terminal Differentiation of Human B Cells into Plasma Cells

    Directory of Open Access Journals (Sweden)

    Gersende Caron

    2015-11-01

    Full Text Available Molecular mechanisms underlying terminal differentiation of B cells into plasma cells are major determinants of adaptive immunity but remain only partially understood. Here we present the transcriptional and epigenomic landscapes of cell subsets arising from activation of human naive B cells and differentiation into plasmablasts. Cell proliferation of activated B cells was linked to a slight decrease in DNA methylation levels, but followed by a committal step in which an S phase-synchronized differentiation switch was associated with an extensive DNA demethylation and local acquisition of 5-hydroxymethylcytosine at enhancers and genes related to plasma cell identity. Downregulation of both TGF-β1/SMAD3 signaling and p53 pathway supported this final step, allowing the emergence of a CD23-negative subpopulation in transition from B cells to plasma cells. Remarkably, hydroxymethylation of PRDM1, a gene essential for plasma cell fate, was coupled to progression in S phase, revealing an intricate connection among cell cycle, DNA (hydroxymethylation, and cell fate determination.

  7. The influence of reactive oxygen species on cell cycle progression in mammalian cells.

    Science.gov (United States)

    Verbon, Eline Hendrike; Post, Jan Andries; Boonstra, Johannes

    2012-12-10

    Cell cycle regulation is performed by cyclins and cyclin dependent kinases (CDKs). Recently, it has become clear that reactive oxygen species (ROS) influence the presence and activity of these enzymes and thereby control cell cycle progression. In this review, we first describe the discovery of enzymes specialized in ROS production: the NADPH oxidase (NOX) complexes. This discovery led to the recognition of ROS as essential players in many cellular processes, including cell cycle progression. ROS influence cell cycle progression in a context-dependent manner via phosphorylation and ubiquitination of CDKs and cell cycle regulatory molecules. We show that ROS often regulate ubiquitination via intermediate phosphorylation and that phosphorylation is thus the major regulatory mechanism influenced by ROS. In addition, ROS have recently been shown to be able to activate growth factor receptors. We will illustrate the diverse roles of ROS as mediators in cell cycle regulation by incorporating phosphorylation, ubiquitination and receptor activation in a model of cell cycle regulation involving EGF-receptor activation. We conclude that ROS can no longer be ignored when studying cell cycle progression. Copyright © 2012 Elsevier B.V. All rights reserved.

  8. Cell-cycle regulatory proteins in human wound healing

    DEFF Research Database (Denmark)

    Bartkova, Jirina; Grøn, Birgitte; Dabelsteen, Erik

    2003-01-01

    the abundance of most of the CKIs, including p27Kip1, p57Kip2, p15ink4b and p18ink4c, was relatively maintained in the migrating epithelial tongue. These data indicate that downmodulation of several G(1)/S-phase cyclins and a relative excess of CKIs may cooperate to ensure the quiescent state of migrating......-cycle regulators critical for G(1)-phase progression and S-phase entry was here analysed immunohistochemically. Compared to normal human mucosa, epithelia migrating to cover 2- or 3-day-old wounds made either in vivo or in an organotypic cell culture all showed loss of the proliferation marker Ki67 and cyclins D(1......) and A, and reduced expression of cyclins D(3) and E, the cyclin D-dependent kinase 4 (CDK4), the MCM7 component of DNA replication origin complexes and the retinoblastoma protein pRb. Among the CDK inhibitors (CKIs), p16ink4a and p21Cip1 were moderately increased and decreased, respectively, whereas...

  9. NSA2, a novel nucleolus protein regulates cell proliferation and cell cycle

    International Nuclear Information System (INIS)

    Zhang, Heyu; Ma, Xi; Shi, Taiping; Song, Quansheng; Zhao, Hongshan; Ma, Dalong

    2010-01-01

    NSA2 (Nop seven-associated 2) was previously identified in a high throughput screen of novel human genes associated with cell proliferation, and the NSA2 protein is evolutionarily conserved across different species. In this study, we revealed that NSA2 is broadly expressed in human tissues and cultured cell lines, and located in the nucleolus of the cell. Both of the putative nuclear localization signals (NLSs) of NSA2, also overlapped with nucleolar localization signals (NoLSs), are capable of directing nucleolar accumulation. Moreover, over-expression of the NSA2 protein promoted cell growth in different cell lines and regulated the G1/S transition in the cell cycle. SiRNA silencing of the NSA2 transcript attenuated the cell growth and dramatically blocked the cell cycle in G1/S transition. Our results demonstrated that NSA2 is a nucleolar protein involved in cell proliferation and cell cycle regulation.

  10. CXCR3 surface expression in human airway epithelial cells: cell cycle dependence and effect on cell proliferation.

    Science.gov (United States)

    Aksoy, Mark O; Yang, Yi; Ji, Rong; Reddy, P J; Shahabuddin, Syed; Litvin, Judith; Rogers, Thomas J; Kelsen, Steven G

    2006-05-01

    We recently demonstrated that human bronchial epithelial cells (HBEC) constitutively express the CXC chemokine receptor CXCR3, which when activated, induces directed cell migration. The present study in HBEC examined the relative expression of the CXCR3 splice variants CXCR3-A and -B, cell cycle dependence of CXCR3 expression, and the effects of the CXCR3 ligand, the interferon-gamma-inducible CXC chemokine I-TAC/CXCL11, on DNA synthesis and cell proliferation. Both CXCR3-A and -B mRNA, assessed by real-time RT-PCR, were expressed in normal HBEC (NHBEC) and the HBEC line 16-HBE. However, CXCR3-B mRNA was 39- and 6-fold greater than CXCR3-A mRNA in NHBEC and 16-HBE, respectively. Although most HBEC (>80%) assessed by flow cytometry and immunofluorescence microscopy contained intracellular CXCR3, only a minority (75%) were in the S + G(2)/M phases of the cell cycle. Stimulation of CXCR3 with I-TAC enhanced thymidine incorporation and cell proliferation and increased p38 and ERK1/2 phosphorylation. These data indicate that 1) human airway epithelial cells primarily express CXCR3-B mRNA, 2) surface expression of CXCR3 is largely confined to the S + G(2)/M phases of the cell cycle, and 3) activation of CXCR3 induces DNA synthesis, cell proliferation, and activation of MAPK pathways. We speculate that activation of CXCR3 exerts a mitogenic effect in HBEC, which may be important during airway mucosal injury in obstructive airway diseases such as asthma and chronic obstructive pulmonary disease.

  11. Pseudolaric acid B induced cell cycle arrest, autophagy and senescence in murine fibrosarcoma l929 cell.

    Science.gov (United States)

    Yu, Jing hua; Liu, Chun yu; Zheng, Gui bin; Zhang, Li Ying; Yan, Ming hui; Zhang, Wen yan; Meng, Xian ying; Yu, Xiao fang

    2013-01-01

    PAB induced various cancer cell apoptosis, cell cycle arrest and senescence. But in cell line murine fibrosarcoma L929, PAB did not induce apoptosis, but autophagy, therefore it was thought by us as a good model to research the relationship of cell cycle arrest, autophagy and senescence bypass apoptosis. Inhibitory ratio was assessed by 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) analysis. Phase contrast microscopy visualized cell morphology. Hoechst 33258 staining for nuclear change, propidium iodode (PI) staining for cell cycle, monodansylcadaverine (MDC) staining for autophagy, and rodanmine 123 staining for mitochondrial membrane potential (MMP) were measured by fluorescence microscopy or flowcytometry. Apoptosis was determined by DNA ladder test. Protein kinase C (PKC) activity was detected by PKC assay kit. SA-β-galactosidase assay was used to detect senescence. Protein expression was examined by western blot. PAB inhibited L929 cell growth in time-and dose-dependent manner. At 12 h, 80 μmol/L PAB induced obvious mitotic arrest; at 24 h, PAB began to induce autophagy; at 36 h, cell-treated with PAB slip into G1 cell cycle; and 3 d PAB induced senescence. In time sequence PAB induced firstly cell cycle arrest, then autophagy, then slippage into G1 phase, lastly senescence. Senescent cells had high level of autophagy, inhibiting autophagy led to apoptosis, and no senescence. PAB activated PKC activity to induce cell cycle arrest, autophagy and senescence, inhibiting PKC activity suppressed cell cycle arrest, autophagy and senescence. PAB induced cell cycle arrest, autophagy and senescence in murine fibrosarcoma L929 cell through PKC.

  12. Influence of the mycotoxins alpha- and beta-zearalenol and deoxynivalenol on the cell cycle of cultured porcine endometrial cells.

    Science.gov (United States)

    Tiemann, U; Viergutz, T; Jonas, L; Schneider, F

    2003-01-01

    The present study investigated the effects of the mycotoxins alpha-zearalenol (alpha-ZOL) and beta-zearalenol (beta-ZOL) at concentrations of 7.5, 15, and 30 microM, and deoxynivalenol (DON) at concentrations of 0.94, 1.88, and 3.76 microM on cell cycle distribution (propidium iodide, PI staining) in combination with the proliferating cell nuclear antigen (PCNA) by flow cytometry. The viability of porcine uterine cells was not impaired at 30 microM alpha-ZOL, whereas beta-ZOL at this concentration and 3.76 microM DON significantly decreased cell number. Some cells showed ultrastructural features of cell death indicated by swollen mitochondria, disrupted cell membranes, and many vacuoles. After 24 and 48h of exposure to alpha-ZOL (7.5, 15, or 30 microM), the cell cycle distribution was still comparable to the control groups. An anti-proliferative effect of beta-ZOL and DON was detected by a significant reduction in the S-phase together with arrest of cells in the G(0)/G(1)-phase. The results show that beta-ZOL (7.5, 15, or 30 microM) and DON (0.94, 1.88, or 3.76 microM) control the progression of cells through the cycle by decreasing S-phase and arresting cells in the G(0)/G(1)-phase of the cell cycle. A significant decrease in the expression of the proliferation marker PCNA amounts indicates that beta-ZOL and DON disengaged cells from active cycling. We confirm that alpha-ZOL possesses a relative binding affinity to porcine uterine cytoplasmic estrogen receptor.

  13. Dimethylfumarate induces cell cycle arrest and apoptosis via regulating intracellular redox systems in HeLa cells.

    Science.gov (United States)

    Han, Guocan; Zhou, Qiang

    2016-12-01

    Dimethylfumarate (DMF) is cytotoxic to several kinds of cells and serves as an anti-tumor drug. This study was designed to investigate the effects and underlying mechanism of DMF on cervical cancer cells. HeLa cells were cultured and treated with 0, 50, 100, 150, and 200 μM DMF, respectively. After 24 h, cell growth was evaluated using Cell Counting Kit-8 (CCK-8) assay and the cell cycle was examined using flow cytometry. In addition, cell apoptosis was detected by Annexin V/propidium iodide (PI) staining and the expressions of caspase-3 and poly-ADP-ribose polymerase (PARP) were detected using western blotting. The redox-related factors were then assessed. Furthermore, all of the indicators were detected in HeLa cells after combined treatment of DMF and N-acetyl-L-cysteine (NAC, an oxygen-free radical scavenger). The cell number and cell growth of HeLa were obviously inhibited by DMF in a dose-dependent manner, as the cell cycle was arrested at G0/G1 phase (P HeLa cells were markedly increased, and the expression levels of caspase-3 and PARP were significantly increased in a DMF concentration-dependent way (P cell proliferation and apoptosis of HeLa cells was mainly related to the intracellular redox systems by depletion of intracellular GSH.

  14. Cycling Memory CD4+ T Cells in HIV Disease Have a Diverse T Cell Receptor Repertoire and a Phenotype Consistent with Bystander Activation

    Science.gov (United States)

    Jiang, Wei; Younes, Souheil-Antoine; Funderburg, Nicholas T.; Mudd, Joseph C.; Espinosa, Enrique; Davenport, Miles P.; Babineau, Denise C.; Sieg, Scott F.

    2014-01-01

    ABSTRACT The mechanisms of increased memory CD4+ T cell cycling in HIV disease are incompletely understood but have been linked to antigen stimulation, homeostatic signals, or exposure to microbial products and the inflammatory cytokines that they induce. We examined the phenotype and Vβ family distribution in cycling memory CD4+ T cells among 52 healthy and 59 HIV-positive (HIV+) donors. Cycling memory CD4+ T cells were proportionally more frequent in subjects with HIV infection than in controls, more often expressed CD38 and PD-1, and less frequently expressed OX40 and intracellular CD40L. OX40 expression on memory CD4+ T cells was induced in vitro by anti-CD3, interleukin-2 (IL-2), IL-7, or IL-15 but not by Toll-like receptor ligands. In HIV+ donors, memory CD4+ T cell cycling was directly related to plasma lipopolysaccharide (LPS) levels, to plasma HIV RNA levels, and to memory CD8+ T cell cycling and was inversely related to peripheral blood CD4+ T cell counts but not to the levels of IL-2, IL-7, or IL-15, while in HIV-negative donors, memory CD4+ T cell cycling was related to IL-7 levels and negatively related to the plasma levels of LPS. In both controls and HIV+ donors, cycling memory CD4+ T cells had a broad distribution of Vβ families comparable to that of noncycling cells. Increased memory CD4+ T cell cycling in HIV disease is reflective of generalized immune activation and not driven primarily by cognate peptide stimulation or exposure to common gamma-chain cytokines. This cycling may be a consequence of exposure to microbial products, to plasma viremia, or, otherwise, to proinflammatory cytokines. IMPORTANCE This work provides evidence that the increased memory CD4+ T cell cycling in HIV infection is not a result of cognate peptide recognition but, rather, is more likely related to the inflammatory environment of HIV infection. PMID:24522925

  15. Effects of γ-radiation on cell growth, cell cycle and promoter methylation of 22 cell cycle genes in the 1321NI astrocytoma cell line.

    Science.gov (United States)

    Alghamian, Yaman; Abou Alchamat, Ghalia; Murad, Hossam; Madania, Ammar

    2017-09-01

    DNA damage caused by radiation initiates biological responses affecting cell fate. DNA methylation regulates gene expression and modulates DNA damage pathways. Alterations in the methylation profiles of cell cycle regulating genes may control cell response to radiation. In this study we investigated the effect of ionizing radiation on the methylation levels of 22 cell cycle regulating genes in correlation with gene expression in 1321NI astrocytoma cell line. 1321NI cells were irradiated with 2, 5 or 10Gy doses then analyzed after 24, 48 and 72h for cell viability using MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazoliu bromide) assay. Flow cytometry were used to study the effect of 10Gy irradiation on cell cycle. EpiTect Methyl II PCR Array was used to identify differentially methylated genes in irradiated cells. Changes in gene expression was determined by qPCR. Azacytidine treatment was used to determine whether DNA methylation affectes gene expression. Our results showed that irradiation decreased cell viability and caused cell cycle arrest at G2/M. Out of 22 genes tested, only CCNF and RAD9A showed some increase in DNA methylation (3.59% and 3.62%, respectively) after 10Gy irradiation, and this increase coincided with downregulation of both genes (by 4 and 2 fold, respectively). with azacytidine confirmed that expression of CCNF and RAD9A genes was regulated by methylation. 1321NI cell line is highly radioresistant and that irradiation of these cells with a 10Gy dose increases DNA methylation of CCNF and RAD9A genes. This dose down-regulates these genes, favoring G2/M arrest. Copyright © 2017 Medical University of Bialystok. Published by Elsevier B.V. All rights reserved.

  16. Progesterone arrested cell cycle progression through progesterone receptor isoform A in pancreatic neuroendocrine neoplasm.

    Science.gov (United States)

    Yazdani, Samaneh; Kasajima, Atsuko; Onodera, Yoshiaki; McNamara, Keely May; Ise, Kazue; Nakamura, Yasuhiro; Tachibana, Tomoyoshi; Motoi, Fuyuhiko; Unno, Michiaki; Sasano, Hironobu

    2018-04-01

    In pancreatic neuroendocrine neoplasms (Pan-NEN) progesterone signaling has been shown to have both inhibitory and stimulatory effects on cell proliferation. The ability of progesterone to inhibit tumor proliferation is of particular interest and is suggested to be mediated through the less abundantly expressed progesterone receptor (PR) isoform A (PRA). To date the mechanistic processes underlying this inhibition of proliferation remain unclear. To examine the mechanism of PRA actions, the human Pan-NEN cell line QGP-1, that endogenously expresses PR isoform B (PRB) without PRA, was transfected with PRA. PRA transfection suppressed the majority of cell cycle related genes increased by progesterone including cyclin A2 (CCNA2), cyclin B1 (CCNB1), cyclin-dependent kinase 1 (CDK1) and cyclin-dependent kinase 2 (CDK2). Importantly, following progesterone administration cell cycle distribution was shifted to S and G2/M phases in the naïve cell line but in PRA-transfected cells, this effect was suppressed. To see if these mechanistic insights were confirmed in patient samples PRA, PRB, CCNA2, CCNB, CDK1 and CDK2 immunoreactivities were assessed in Pan-NEN cases. Higher levels of cell cycle markers were associated with higher WHO grade tumors and correlations between the markers suggested formation of cyclin/CDK activated complexes in S and G2/M phases. PRA expression was associated with inverse correlation of all cell cycle markers. Collectively, these results indicate that progesterone signals through PRA negatively regulates cell cycle progression through suppressing S and G2/M phases and downregulation of cell cycle phases specific cyclins/CDKs. Copyright © 2018 Elsevier Ltd. All rights reserved.

  17. Cyclebase 3.0: a multi-organism database on cell-cycle regulation and phenotypes

    DEFF Research Database (Denmark)

    Santos Delgado, Alberto; Wernersson, Rasmus; Jensen, Lars Juhl

    2015-01-01

    are not easily accessed, analyzed and combined due to their inherent heterogeneity. To address this, we have created Cyclebase-available at http://www.cyclebase.org-an online database that allows users to easily visualize and download results from genome-wide cell-cycle-related experiments. In Cyclebase version...... 3.0, we have updated the content of the database to reflect changes to genome annotation, added new mRNAand protein expression data, and integrated cell-cycle phenotype information from high-content screens and model-organism databases. The new version of Cyclebase also features a new web interface......, designed around an overview figure that summarizes all the cell-cycle-related data for a gene....

  18. Effects of caffeine on protein phosphorylation and cell cycle progression in X-irradiated two-cell mouse embryos

    International Nuclear Information System (INIS)

    Jung, Th.; Streffer, C.

    1992-01-01

    To understand the mechanism of the caffeine-induced uncoupling of mitosis and the cellular reactions to DNA-damaging agents, the authors studied the effects of caffeine treatment on cell cycle progression and protein phosphorylation in two-cell mouse embryos after X-irradiation. Caffeine alone had no effect on timing of and changes in phosphorylation associated with the embryonic cell cycle. In combination with X-rays, caffeine was able to override the radiation induced G 2 block and restored normal timing of these phosphorylation changes after X-irradiation. New additional changes in protein phosphorylation appeared after the combined treatment. Isobutyl-methylxanthine (IBMX), a substance chemically related to caffeine but a more specific inhibitor of the phosphodiesterase that breaks down cyclic AMP, reduced radiation induced G 2 block from 4 to 5 h to about 1 h and restored the cell cycle associated changes in protein phosphorylation. (author)

  19. On the Relation Between Spotless Days and the Sunspot Cycle

    Science.gov (United States)

    Wilson, Robert M.; Hathaway, David H.

    2005-01-01

    Spotless days are examined as a predictor for the size and timing of a sunspot cycle. For cycles 16-23 the first spotless day for a new cycle, which occurs during the decline of the old cycle, is found to precede minimum amplitude for the new cycle by about approximately equal to 34 mo, having a range of 25-40 mo. Reports indicate that the first spotless day for cycle 24 occurred in January 2004, suggesting that minimum amplitude for cycle 24 should be expected before April 2007, probably sometime during the latter half of 2006. If true, then cycle 23 will be classified as a cycle of shorter period, inferring further that cycle 24 likely will be a cycle of larger than average minimum and maximum amplitudes and faster than average rise, peaking sometime in 2010.

  20. Isolation of cell cycle-dependent gamma ray-sensitive Chinese hamster ovary cell

    International Nuclear Information System (INIS)

    Stamato, T.D.; Weinstein, R.; Giaccia, A.; Mackenzie, L.

    1983-01-01

    A technique for the isolation of gamma ray-sensitive Chinese hamster ovary (CHO) cell mutants is described, which uses nylon cloth replica plating and photography with dark-field illumination to directly monitor colonies for growth after gamma irradiation. Two gamma ray-sensitive mutants were isolated using this method. One of these cells (XR-1) had a two-slope survival curve: an initial steep slope and then a flattening of the curve at about 10% survival. Subsequently, it was found that this cell is sensitive to gamma irradiation in G1, early S, and late G2 phases of the cell cycle, whereas in the resistant phase (late S phase) its survival approaches that of the parental cells. The D37 in the sensitive G1 period is approximately 30 rads, compared with 300 rads of the parental cell. This mutant cell is also sensitive to killing by the DNA breaking agent, bleomycin, but is relatively insensitive to UV light and ethyl methane sulfonate, suggesting that the defect is specific for agents that produce DNA strand breakage

  1. Astaxanthin Inhibits Proliferation and Induces Apoptosis and Cell Cycle Arrest of Mice H22 Hepatoma Cells.

    Science.gov (United States)

    Shao, Yiye; Ni, Yanbo; Yang, Jing; Lin, Xutao; Li, Jun; Zhang, Lixia

    2016-06-23

    BACKGROUND It is widely recognized that astaxanthin (ASX), a member of the carotenoid family, has strong biological activities including antioxidant, anti-inflammation, and immune-modulation activities. Previous studies have confirmed that ASX can effectively inhibit hepatoma cells in vitro. MATERIAL AND METHODS MTT was used to assay proliferation of mice H22 cells, and flow cytometry was used to determine apoptosis and cell cycle arrest of H22 cells in vitro and in vivo. Moreover, anti-tumor activity of ASX was observed in mice. RESULTS ASX inhibited the proliferation of H22 cells, promoted cell necrosis, and induced cell cycle arrest in G2 phase in vitro and in vivo. CONCLUSIONS This study indicated that ASX can inhibit proliferation and induce apoptosis and cell cycle arrest in mice H22 hepatoma cells in vitro and in vivo.

  2. Chemical dissection of the cell cycle: probes for cell biology and anti-cancer drug development.

    Science.gov (United States)

    Senese, S; Lo, Y C; Huang, D; Zangle, T A; Gholkar, A A; Robert, L; Homet, B; Ribas, A; Summers, M K; Teitell, M A; Damoiseaux, R; Torres, J Z

    2014-10-16

    Cancer cell proliferation relies on the ability of cancer cells to grow, transition through the cell cycle, and divide. To identify novel chemical probes for dissecting the mechanisms governing cell cycle progression and cell division, and for developing new anti-cancer therapeutics, we developed and performed a novel cancer cell-based high-throughput chemical screen for cell cycle modulators. This approach identified novel G1, S, G2, and M-phase specific inhibitors with drug-like properties and diverse chemotypes likely targeting a broad array of processes. We further characterized the M-phase inhibitors and highlight the most potent M-phase inhibitor MI-181, which targets tubulin, inhibits tubulin polymerization, activates the spindle assembly checkpoint, arrests cells in mitosis, and triggers a fast apoptotic cell death. Importantly, MI-181 has broad anti-cancer activity, especially against BRAF(V600E) melanomas.

  3. Akt1 intramitochondrial cycling is a crucial step in the redox modulation of cell cycle progression.

    Directory of Open Access Journals (Sweden)

    Valeria Gabriela Antico Arciuch

    2009-10-01

    Full Text Available Akt is a serine/threonine kinase involved in cell proliferation, apoptosis, and glucose metabolism. Akt is differentially activated by growth factors and oxidative stress by sequential phosphorylation of Ser(473 by mTORC2 and Thr(308 by PDK1. On these bases, we investigated the mechanistic connection of H(2O(2 yield, mitochondrial activation of Akt1 and cell cycle progression in NIH/3T3 cell line with confocal microscopy, in vivo imaging, and directed mutagenesis. We demonstrate that modulation by H(2O(2 entails the entrance of cytosolic P-Akt1 Ser(473 to mitochondria, where it is further phosphorylated at Thr(308 by constitutive PDK1. Phosphorylation of Thr(308 in mitochondria determines Akt1 passage to nuclei and triggers genomic post-translational mechanisms for cell proliferation. At high H(2O(2, Akt1-PDK1 association is disrupted and P-Akt1 Ser(473 accumulates in mitochondria in detriment to nuclear translocation; accordingly, Akt1 T308A is retained in mitochondria. Low Akt1 activity increases cytochrome c release to cytosol leading to apoptosis. As assessed by mass spectra, differential H(2O(2 effects on Akt1-PDK interaction depend on the selective oxidation of Cys(310 to sulfenic or cysteic acids. These results indicate that Akt1 intramitochondrial-cycling is central for redox modulation of cell fate.

  4. Arecoline decreases interleukin-6 production and induces apoptosis and cell cycle arrest in human basal cell carcinoma cells

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Li-Wen [Department of Medical Laboratory Science and Biotechnology, Kaohsiung Medical University, Kaohsiung 80708, Taiwan (China); Hsieh, Bau-Shan; Cheng, Hsiao-Ling [Department of Biochemistry, Faculty of Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung 80708, Taiwan (China); Hu, Yu-Chen [Graduate Institute of Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung 80708, Taiwan (China); Chang, Wen-Tsan [Graduate Institute of Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung 80708, Taiwan (China); Division of Hepatobiliarypancreatic Surgery, Department of Surgery, Kaohsiung Medical University Hospital, Kaohsiung 80708, Taiwan (China); Chang, Kee-Lung, E-mail: Chang.KeeLung@msa.hinet.net [Department of Biochemistry, Faculty of Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung 80708, Taiwan (China); Graduate Institute of Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung 80708, Taiwan (China)

    2012-01-15

    Arecoline, the most abundant areca alkaloid, has been reported to decrease interleukin-6 (IL-6) levels in epithelial cancer cells. Since IL-6 overexpression contributes to the tumorigenic potency of basal cell carcinoma (BCC), this study was designed to investigate whether arecoline altered IL-6 expression and its downstream regulation of apoptosis and the cell cycle in cultured BCC-1/KMC cells. BCC-1/KMC cells and a human keratinocyte cell line, HaCaT, were treated with arecoline at concentrations ranging from 10 to 100 μg/ml, then IL-6 production and expression of apoptosis- and cell cycle progress-related factors were examined. After 24 h exposure, arecoline inhibited BCC-1/KMC cell growth and decreased IL-6 production in terms of mRNA expression and protein secretion, but had no effect on HaCaT cells. Analysis of DNA fragmentation and chromatin condensation showed that arecoline induced apoptosis of BCC-1/KMC cells in a dose-dependent manner, activated caspase-3, and decreased expression of the anti-apoptotic protein Bcl-2. In addition, arecoline induced progressive and sustained accumulation of BCC-1/KMC cells in G2/M phase as a result of reducing checkpoint Cdc2 activity by decreasing Cdc25C phosphatase levels and increasing p53 levels. Furthermore, subcutaneous injection of arecoline led to decreased BCC-1/KMC tumor growth in BALB/c mice by inducing apoptosis. This study demonstrates that arecoline has potential for preventing BCC tumorigenesis by reducing levels of the tumor cell survival factor IL-6, increasing levels of the tumor suppressor factor p53, and eliciting cell cycle arrest, followed by apoptosis. Highlights: ► Arecoline has potential to prevent against basal cell carcinoma tumorigenesis. ► It has more effectiveness on BCC as compared with a human keratinocyte cell line. ► Mechanisms involved including reducing tumor cells’ survival factor IL-6, ► Decreasing Cdc25C phosphatase, enhancing tumor suppressor factor p53, ► Eliciting G2/M

  5. Androgen Receptors Expression in Pituitary of Male Viscacha in relation to Growth and Reproductive Cycle

    Directory of Open Access Journals (Sweden)

    Verónica Palmira Filippa

    2015-01-01

    Full Text Available The aim of this work was to study the androgen receptors (AR expression in pituitary pars distalis (PD of male viscachas in relation to growth and reproductive cycle. AR were detected by immunocytochemistry and quantified by image analysis. Pituitary glands from fetus, immature, prepubertal, and adult viscachas during their reproductive cycle were used. In the fetal PD, the immunoreactivity (ir was mainly cytoplasmic. In immature and prepubertal animals, AR-ir was cytoplasmic (ARc-ir and nuclear (ARn-ir in medial region. In adult animals, ARn-ir cells were numerous at caudal end. AR regionalization varied between the PD zones in relation to growth. In immature animals, the ARn-ir increased whereas the cytoplasmic expression decreased in relation to the fetal glands. The percentage of ARc-ir cells increased in prepubertal animals whereas the nuclear AR expression was predominant in adult viscachas. The AR expression changed in adults, showing minimum percentage in the gonadal regression period. The variation of nuclear AR expression was directly related with testosterone concentration. These results demonstrated variations in the immunostaining pattern, regionalization, and number of AR-ir cells throughout development, growth, and reproductive cycle, suggesting the involvement of AR in the regulation of the pituitary activity of male viscacha.

  6. Effects of [3H]UdR on the cell-cycle progression of L1210 cells

    International Nuclear Information System (INIS)

    Darzynkiewicz, Z.; Carter, S.; Kimmel, M.

    1984-01-01

    Tritium-labelled uridine (( 3 H)UdR)perturbs progression of L1210 cells through the mitotic cycle. A slowdown of G 2 cells is observed 2 hr after addition of 0.5-5.0 μci/ml of ( 3 H)UdR into cultures. At 2.5-5.0 μCi/ml of ( 3 H)UdR a slowdown of cell progression through S is also apparent. Additionally, there is an increase in the number of cells with DNA values higher than 4C in cultures growing in the presence of ( 3 H)UdR for 8-24 hr. A pulse of ( 3 H)UdR of 2 hr duration labels predominantly (95%) cellular RNA. The first cell-cycle effects (G 2 slowdown) are observed when the amount of the incorporated ( 3 H)UdR is such that, on average there are fewer than thirty-six ( 3 H) decays per cell which corresponds to approximately 12-19 rads. The S-phase slowdown is seen at a dose of incorporated ( 3 H)UdR twice as high as that inducing G 2 effects. The specific localization of ( 3 H)UdR in nucleoli, peripheral nucleoplasm and in cytoplasm, as well as differences in the kinetics of the incorporation in relation to phases of the cell cycle are discussed. Mathematical modelling of the cell-cycle effects of ( 3 H)UdR is provided. (author)

  7. Lineage correlations of single cell division time as a probe of cell-cycle dynamics.

    Science.gov (United States)

    Sandler, Oded; Mizrahi, Sivan Pearl; Weiss, Noga; Agam, Oded; Simon, Itamar; Balaban, Nathalie Q

    2015-03-26

    Stochastic processes in cells are associated with fluctuations in mRNA, protein production and degradation, noisy partition of cellular components at division, and other cell processes. Variability within a clonal population of cells originates from such stochastic processes, which may be amplified or reduced by deterministic factors. Cell-to-cell variability, such as that seen in the heterogeneous response of bacteria to antibiotics, or of cancer cells to treatment, is understood as the inevitable consequence of stochasticity. Variability in cell-cycle duration was observed long ago; however, its sources are still unknown. A central question is whether the variance of the observed distribution originates from stochastic processes, or whether it arises mostly from a deterministic process that only appears to be random. A surprising feature of cell-cycle-duration inheritance is that it seems to be lost within one generation but to be still present in the next generation, generating poor correlation between mother and daughter cells but high correlation between cousin cells. This observation suggests the existence of underlying deterministic factors that determine the main part of cell-to-cell variability. We developed an experimental system that precisely measures the cell-cycle duration of thousands of mammalian cells along several generations and a mathematical framework that allows discrimination between stochastic and deterministic processes in lineages of cells. We show that the inter- and intra-generation correlations reveal complex inheritance of the cell-cycle duration. Finally, we build a deterministic nonlinear toy model for cell-cycle inheritance that reproduces the main features of our data. Our approach constitutes a general method to identify deterministic variability in lineages of cells or organisms, which may help to predict and, eventually, reduce cell-to-cell heterogeneity in various systems, such as cancer cells under treatment.

  8. Lineage-specific interface proteins match up the cell cycle and differentiation in embryo stem cells

    DEFF Research Database (Denmark)

    Re, Angela; Workman, Christopher; Waldron, Levi

    2014-01-01

    The shortage of molecular information on cell cycle changes along embryonic stem cell (ESC) differentiation prompts an in silico approach, which may provide a novel way to identify candidate genes or mechanisms acting in coordinating the two programs. We analyzed germ layer specific gene expression...... changes during the cell cycle and ESC differentiation by combining four human cell cycle transcriptome profiles with thirteen in vitro human ESC differentiation studies. To detect cross-talk mechanisms we then integrated the transcriptome data that displayed differential regulation with protein...... interaction data. A new class of non-transcriptionally regulated genes was identified, encoding proteins which interact systematically with proteins corresponding to genes regulated during the cell cycle or cell differentiation, and which therefore can be seen as interface proteins coordinating the two...

  9. Growth inhibition and cell cycle arrest effects of epigallocatechin gallate in the NBT-II bladder tumour cell line.

    Science.gov (United States)

    Chen, J J; Ye, Z-Q; Koo, M W L

    2004-05-01

    To examine the growth inhibition and cell cycle arrest effects of epigallocatechin gallate (EGCG), a major constituent of green tea polyphenols, on the NBT-II bladder tumour cell line. Growth inhibition and cell cycle arrest effects of EGCG were evaluated by the tetrazolium assay, flow cytometry and apoptotic DNA ladder tests. The cell cycle-related oncogene and protein expressions in NBT-II bladder tumour cells, when incubated with EGCG, were detected with reverse transcription-polymerase chain reaction (RT-PCR) and Western blot analysis. EGCG inhibited growth of the NBT-II bladder tumour cells in a dose- and time-dependent manner. Flow cytometry showed a G0/G1 arrest in cells when cultured with EGCG at doses of 10, 20 or 40 micro mol/L for 48 or 72 h. The apoptotic DNA ladder test showed that EGCG at 10 micro mol/L induced early apoptosis after 48 h of incubation. A down-regulation of cyclin D1 was detected by RT-PCR when the cells were incubated with EGCG (20 micro mol/L for 48 h. EGCG also down-regulated protein expression of cyclin D1, cyclin-dependent kinase 4/6 and phosphorylated retinoblastoma protein, in both a time- and dose-dependent manner, when detected by Western blot. EGCG had growth inhibition and cell-cycle arrest effects in NBT-II bladder tumour cells by down-regulating the cyclin D1, cyclin-dependent kinase 4/6 and retinoblastoma protein machinery for regulating cell-cycle progression.

  10. LTA4H regulates cell cycle and skin carcinogenesis.

    Science.gov (United States)

    Oi, Naomi; Yamamoto, Hiroyuki; Langfald, Alyssa; Bai, Ruihua; Lee, Mee-Hyun; Bode, Ann M; Dong, Zigang

    2017-07-01

    Leukotriene A4 hydrolase (LTA4H), a bifunctional zinc metallo-enzyme, is reportedly overexpressed in several human cancers. Our group has focused on LTA4H as a potential target for cancer prevention and/or therapy. In the present study, we report that LTA4H is a key regulator of cell cycle at the G0/G1 phase acting by negatively regulating p27 expression in skin cancer. We found that LTA4H is overexpressed in human skin cancer tissue. Knocking out LTA4H significantly reduced skin cancer development in the 7,12-dimethylbenz(a)anthracene (DMBA)-initiated/12-O-tetradecanoylphorbol-13-acetate (TPA)-promoted two-stage skin cancer mouse model. LTA4H depletion dramatically decreased anchorage-dependent and -independent skin cancer cell growth by inducing cell cycle arrest at the G0/G1 phase. Moreover, our findings showed that depletion of LTA4H enhanced p27 protein stability, which was associated with decreased phosphorylation of CDK2 at Thr160 and inhibition of the CDK2/cyclin E complex, resulting in down-regulated p27 ubiquitination. These findings indicate that LTA4H is critical for skin carcinogenesis and is an important mediator of cell cycle and the data begin to clarify the mechanisms of LTA4H's role in cancer development. © The Author 2017. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  11. The cell cycle checkpoint inhibitors in the treatment of leukemias.

    Science.gov (United States)

    Ghelli Luserna di Rora', A; Iacobucci, I; Martinelli, G

    2017-03-29

    The inhibition of the DNA damage response (DDR) pathway in the treatment of cancers has recently reached an exciting stage with several cell cycle checkpoint inhibitors that are now being tested in several clinical trials in cancer patients. Although the great amount of pre-clinical and clinical data are from the solid tumor experience, only few studies have been done on leukemias using specific cell cycle checkpoint inhibitors. This review aims to summarize the most recent data found on the biological mechanisms of the response to DNA damages highlighting the role of the different elements of the DDR pathway in normal and cancer cells and focusing on the main genetic alteration or aberrant gene expression that has been found on acute and chronic leukemias. This review, for the first time, outlines the most important pre-clinical and clinical data available on the efficacy of cell cycle checkpoint inhibitors in single agent and in combination with different agents normally used for the treatment of acute and chronic leukemias.

  12. Profiling of Hepatocellular Carcinoma Cell Cycle Regulating Genes Targeted by Calycosin

    Directory of Open Access Journals (Sweden)

    Dongqing Zhang

    2013-01-01

    Full Text Available We cocultured calycosin with human hepatocellular carcinoma cell line (BEL-7402 to investigate the effect on cell proliferation. Calycosin can markedly block the cell growth in G1 phase (P<0.01 on the IC50 concentration. There were seventeen genes involved in cell-cycle regulation showing differentially expressed in treated cells detected by gene chip. Eight genes were upregulated and nine genes were downregulated. Downregulated TFDP-1, CDKN2D, and SPK2 and upregulated CDC2 and CCNB1 might affect cell cycle of tumor cells. Furthermore, we checked the transcription pattern using 2D gel method to find different expression of proteins in human hepatocellular carcinoma cells after exposure to calycosin. Fourteen proteins were identified by matrix-assisted laser desorption/ionization-time of flight-mass spectrometry (MALDI-TOF-MS. Twelve proteins expression were increased such as transgelin 2, pyridoxine 5′-phosphate, stress-induced-phosphoprotein 1, peroxiredoxin 1, endoplasmic reticulum protein 29, and phosphoglycerate mutase 1. Only thioredoxin peroxidase and high-mobility group box1 proteins’ expression decreased. Both genes and proteins changes might be relate to the mechanism of antitumor effect under treatment of calycosin. In conclusion, calycosin has a potential effect to inhibit the BEL-7402 cell growth by inhibiting some oncogene expression and increasing anticancer genes expression, what is more, by blocking cell cycle.

  13. Therapeutic potential of targeting cell division cycle associated 5 for oral squamous cell carcinoma.

    Science.gov (United States)

    Tokuzen, Norihiko; Nakashiro, Koh-ichi; Tanaka, Hiroshi; Iwamoto, Kazuki; Hamakawa, Hiroyuki

    2016-01-19

    Molecularly targeted drugs are used in the treatment of a variety of malignant tumors, but this approach to developing novel therapies for oral squamous cell carcinoma (OSCC) has lagged behind the progress seen for other cancers. We have attempted to find appropriate molecular targets for OSCC and identified cell division cycle associated 5 (CDCA5) as a cancer-related gene which was overexpressed in all the human OSCC cells tested by microarray analysis. In this study, we investigated the expression and function of CDCA5 in OSCC. First, we confirmed that CDCA5 was overexpressed in 4 human OSCC cell lines by quantitative RT-PCR and Western blotting. We then tested the effect of synthetic small interfering RNAs specific for CDCA5 on the growth and invasion of human OSCC cells. Knockdown of CDCA5 markedly inhibited the growth of OSCC cells in vitro and in vivo. We also examined the expression of CDCA5 protein in 80 cases of OSCC immunohistochemically and found a significant association between CDCA5 expression levels and overall survival. These results suggest that CDCA5 functions as a critical gene supporting OSCC progression and that targeting CDCA5 may be a useful therapeutic strategy for OSCC.

  14. Systematic identification of yeast cell cycle transcription factors using multiple data sources

    Directory of Open Access Journals (Sweden)

    Li Wen-Hsiung

    2008-12-01

    Full Text Available Abstract Background Eukaryotic cell cycle is a complex process and is precisely regulated at many levels. Many genes specific to the cell cycle are regulated transcriptionally and are expressed just before they are needed. To understand the cell cycle process, it is important to identify the cell cycle transcription factors (TFs that regulate the expression of cell cycle-regulated genes. Results We developed a method to identify cell cycle TFs in yeast by integrating current ChIP-chip, mutant, transcription factor binding site (TFBS, and cell cycle gene expression data. We identified 17 cell cycle TFs, 12 of which are known cell cycle TFs, while the remaining five (Ash1, Rlm1, Ste12, Stp1, Tec1 are putative novel cell cycle TFs. For each cell cycle TF, we assigned specific cell cycle phases in which the TF functions and identified the time lag for the TF to exert regulatory effects on its target genes. We also identified 178 novel cell cycle-regulated genes, among which 59 have unknown functions, but they may now be annotated as cell cycle-regulated genes. Most of our predictions are supported by previous experimental or computational studies. Furthermore, a high confidence TF-gene regulatory matrix is derived as a byproduct of our method. Each TF-gene regulatory relationship in this matrix is supported by at least three data sources: gene expression, TFBS, and ChIP-chip or/and mutant data. We show that our method performs better than four existing methods for identifying yeast cell cycle TFs. Finally, an application of our method to different cell cycle gene expression datasets suggests that our method is robust. Conclusion Our method is effective for identifying yeast cell cycle TFs and cell cycle-regulated genes. Many of our predictions are validated by the literature. Our study shows that integrating multiple data sources is a powerful approach to studying complex biological systems.

  15. Hippo signaling controls cell cycle and restricts cell plasticity in planarians.

    Directory of Open Access Journals (Sweden)

    Nídia de Sousa

    2018-01-01

    Full Text Available The Hippo pathway plays a key role in regulating cell turnover in adult tissues, and abnormalities in this pathway are consistently associated with human cancers. Hippo was initially implicated in the control of cell proliferation and death, and its inhibition is linked to the expansion of stem cells and progenitors, leading to larger organ size and tumor formation. To understand the mechanism by which Hippo directs cell renewal and promotes stemness, we studied its function in planarians. These stem cell-based organisms are ideal models for the analysis of the complex cellular events underlying tissue renewal in the whole organism. hippo RNA interference (RNAi in planarians decreased apoptotic cell death, induced cell cycle arrest, and could promote the dedifferentiation of postmitotic cells. hippo RNAi resulted in extensive undifferentiated areas and overgrowths, with no effect on body size or cell number. We propose an essential role for hippo in controlling cell cycle, restricting cell plasticity, and thereby preventing tumoral transformation.

  16. Host actin polymerization tunes the cell division cycle of an intracellular pathogen.

    Science.gov (United States)

    Siegrist, M Sloan; Aditham, Arjun K; Espaillat, Akbar; Cameron, Todd A; Whiteside, Sarah A; Cava, Felipe; Portnoy, Daniel A; Bertozzi, Carolyn R

    2015-04-28

    Growth and division are two of the most fundamental capabilities of a bacterial cell. While they are well described for model organisms growing in broth culture, very little is known about the cell division cycle of bacteria replicating in more complex environments. Using a D-alanine reporter strategy, we found that intracellular Listeria monocytogenes (Lm) spend a smaller proportion of their cell cycle dividing compared to Lm growing in broth culture. This alteration to the cell division cycle is independent of bacterial doubling time. Instead, polymerization of host-derived actin at the bacterial cell surface extends the non-dividing elongation period and compresses the division period. By decreasing the relative proportion of dividing Lm, actin polymerization biases the population toward cells with the highest propensity to form actin tails. Thus, there is a positive-feedback loop between the Lm cell division cycle and a physical interaction with the host cytoskeleton. Copyright © 2015 The Authors. Published by Elsevier Inc. All rights reserved.

  17. Extracellular matrix-dependent myosin dynamics during G1-S phase cell cycle progression in hepatocytes

    International Nuclear Information System (INIS)

    Bhadriraju, Kiran; Hansen, Linda K.

    2004-01-01

    Cell spreading and proliferation are tightly coupled in anchorage-dependent cells. While adhesion-dependent proliferation signals require an intact actin cytoskeleton, and some of these signals such as ERK activation have been characterized, the role of myosin in spreading and cell cycle progression under different extracellular matrix (ECM) conditions is not known. Studies presented here examine changes in myosin activity in freshly isolated hepatocytes under ECM conditions that promote either proliferation (high fibronectin density) or growth arrest (low fibronectin density). Three different measures were obtained and related to both spreading and cell cycle progression: myosin protein levels and association with cytoskeleton, myosin light chain phosphorylation, and its ATPase activity. During the first 48 h in culture, corresponding with transit through G1 phase, there was a six-fold increase in both myosin protein levels and myosin association with actin cytoskeleton. There was also a steady increase in myosin light chain phosphorylation and ATPase activity with spreading, which did not occur in non-spread, growth-arrested cells on low density of fibronectin. Myosin-inhibiting drugs blocked ERK activation, cyclin D1 expression, and S phase entry. Overexpression of the cell cycle protein cyclin D1 overcame both ECM-dependent and actomyosin-dependent inhibition of DNA synthesis, suggesting that cyclin D1 is a key event downstream of myosin-dependent cell cycle regulation

  18. Linalool Induces Cell Cycle Arrest and Apoptosis in Leukemia Cells and Cervical Cancer Cells through CDKIs

    Directory of Open Access Journals (Sweden)

    Mei-Yin Chang

    2015-11-01

    Full Text Available Plantaginaceae, a popular traditional Chinese medicine, has long been used for treating various diseases from common cold to cancer. Linalool is one of the biologically active compounds that can be isolated from Plantaginaceae. Most of the commonly used cytotoxic anticancer drugs have been shown to induce apoptosis in susceptible tumor cells. However, the signaling pathway for apoptosis remains undefined. In this study, the cytotoxic effect of linalool on human cancer cell lines was investigated. Water-soluble tetrazolium salts (WST-1 based colorimetric cellular cytotoxicity assay, was used to test the cytotoxic ability of linalool against U937 and HeLa cells, and flow cytometry (FCM and genechip analysis were used to investigate the possible mechanism of apoptosis. These results demonstrated that linalool exhibited a good cytotoxic effect on U937 and HeLa cells, with the IC50 value of 2.59 and 11.02 μM, respectively, compared with 5-FU with values of 4.86 and 12.31 μM, respectively. After treating U937 cells with linalool for 6 h, we found an increased sub-G1 peak and a dose-dependent phenomenon, whereby these cells were arrested at the G0/G1 phase. Furthermore, by using genechip analysis, we observed that linalool can promote p53, p21, p27, p16, and p18 gene expression. Therefore, this study verified that linalool can arrest the cell cycle of U937 cells at the G0/G1 phase and can arrest the cell cycle of HeLa cells at the G2/M phase. Its mechanism facilitates the expression of the cyclin-dependent kinases inhibitors (CDKIs p53, p21, p27, p16, and p18, as well as the non-expression of cyclin-dependent kinases (CDKs activity.

  19. Linalool Induces Cell Cycle Arrest and Apoptosis in Leukemia Cells and Cervical Cancer Cells through CDKIs.

    Science.gov (United States)

    Chang, Mei-Yin; Shieh, Den-En; Chen, Chung-Chi; Yeh, Ching-Sheng; Dong, Huei-Ping

    2015-11-26

    Plantaginaceae, a popular traditional Chinese medicine, has long been used for treating various diseases from common cold to cancer. Linalool is one of the biologically active compounds that can be isolated from Plantaginaceae. Most of the commonly used cytotoxic anticancer drugs have been shown to induce apoptosis in susceptible tumor cells. However, the signaling pathway for apoptosis remains undefined. In this study, the cytotoxic effect of linalool on human cancer cell lines was investigated. Water-soluble tetrazolium salts (WST-1) based colorimetric cellular cytotoxicity assay, was used to test the cytotoxic ability of linalool against U937 and HeLa cells, and flow cytometry (FCM) and genechip analysis were used to investigate the possible mechanism of apoptosis. These results demonstrated that linalool exhibited a good cytotoxic effect on U937 and HeLa cells, with the IC50 value of 2.59 and 11.02 μM, respectively, compared with 5-FU with values of 4.86 and 12.31 μM, respectively. After treating U937 cells with linalool for 6 h, we found an increased sub-G1 peak and a dose-dependent phenomenon, whereby these cells were arrested at the G0/G1 phase. Furthermore, by using genechip analysis, we observed that linalool can promote p53, p21, p27, p16, and p18 gene expression. Therefore, this study verified that linalool can arrest the cell cycle of U937 cells at the G0/G1 phase and can arrest the cell cycle of HeLa cells at the G2/M phase. Its mechanism facilitates the expression of the cyclin-dependent kinases inhibitors (CDKIs) p53, p21, p27, p16, and p18, as well as the non-expression of cyclin-dependent kinases (CDKs) activity.

  20. Synchronization of Green Algae by Light and Dark Regimes for Cell Cycle and Cell Division Studies.

    Science.gov (United States)

    Hlavová, Monika; Vítová, Milada; Bišová, Kateřina

    2016-01-01

    A synchronous population of cells is one of the prerequisites for studying cell cycle processes such as DNA replication, nuclear and cellular division. Green algae dividing by multiple fission represent a unique single cell system enabling the preparation of highly synchronous cultures by application of a light-dark regime similar to what they experience in nature. This chapter provides detailed protocols for synchronization of different algal species by alternating light-dark cycles; all critical points are discussed extensively. Moreover, detailed information on basic analysis of cell cycle progression in such cultures is presented, including analyses of nuclear, cellular, and chloroplast divisions. Modifications of basic protocols that enable changes in cell cycle progression are also suggested so that nuclear or chloroplast divisions can be followed separately.

  1. Life-cycle analysis of product integrated polymer solar cells

    DEFF Research Database (Denmark)

    Espinosa Martinez, Nieves; García-Valverde, Rafael; Krebs, Frederik C

    2011-01-01

    A life cycle analysis (LCA) on a product integrated polymer solar module is carried out in this study. These assessments are well-known to be useful in developmental stages of a product in order to identify the bottlenecks for the up-scaling in its production phase for several aspects spanning from...... economics through design to functionality. An LCA study was performed to quantify the energy use and greenhouse gas (GHG) emissions from electricity use in the manufacture of a light-weight lamp based on a plastic foil, a lithium-polymer battery, a polymer solar cell, printed circuitry, blocking diode......, switch and a white light emitting semiconductor diode. The polymer solar cell employed in this prototype presents a power conversion efficiency in the range of 2 to 3% yielding energy payback times (EPBT) in the range of 1.3–2 years. Based on this it is worthwhile to undertake a life-cycle study...

  2. Cell identity bookmarking through heterogeneous chromatin landscape maintenance during the cell cycle.

    Science.gov (United States)

    Luo, Huaibing; Xi, Yanping; Li, Wei; Li, Jin; Li, Yan; Dong, Shihua; Peng, Lina; Liu, Yaping; Yu, Wenqiang

    2017-11-01

    Genetic and epigenetic information are faithfully duplicated and accurately transmitted to daughter cells to preserve cell identity during the cell cycle. However, how the chromatin-based epigenetic information beyond DNA sequence is stably transmitted along with the disruption and re-establishment of chromatin structure within a cell cycle remains largely unexplored. Through comprehensive analysis DNA methylation and nucleosome positioning patterns of HepG2 cells in G0/G1, early S, late S and G2/M phases, we found that DNA methylation may act as the prime element for epigenetic inheritance after replication, as DNA methylation was extremely stable in each cell cycle phase, while nucleosome occupancy showed notable phase dependent fluctuation. Nucleosome-Secured Regions (NSRs) occupied by polycomb-repressed chromatin played a role in repressing the irrelevant cell type-specific genes and were essential for preventing irrelevant transcription factors binding, while the well-defined Nucleosome-Depleted Regions (NDRs) marked the genes crucial for cell identity maintenance. Chromatin structure at NSRs and NDRs was well maintained throughout the cell cycle, which played crucial roles in steadily preserving the transcriptional identity of the cell to fulfill cell identity maintenance. Collectively, our results demonstrated that while chromatin architecture underwent dynamic changes during cell cycle progression, DNA methylation together with NSRs and NDRs were stable epigenetic elements that were required for faithful transmission to the daughter cell to accurately maintain cell identity during the cell cycle. © The Author 2017. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  3. Thermodynamic analysis of an integrated solid oxide fuel cell cycle with a rankine cycle

    International Nuclear Information System (INIS)

    Rokni, Masoud

    2010-01-01

    Hybrid systems consisting of solid oxide fuel cells (SOFC) on the top of a steam turbine (ST) are investigated. The plants are fired by natural gas (NG). A desulfurization reactor removes the sulfur content in the fuel while a pre-reformer breaks down the heavier hydro-carbons. The pre-treated fuel enters then into the anode side of the SOFC. The remaining fuels after the SOFC stacks enter a burner for further burning. The off-gases are then used to produce steam for a Rankine cycle in a heat recovery steam generator (HRSG). Different system setups are suggested. Cyclic efficiencies up to 67% are achieved which is considerably higher than the conventional combined cycles (CC). Both adiabatic steam reformer (ASR) and catalytic partial oxidation (CPO) fuel pre-reformer reactors are considered in this investigation.

  4. RNAi in Drosophila S2 cells as a tool for studying cell cycle progression.

    Science.gov (United States)

    Bettencourt-Dias, Mónica; Goshima, Gohta

    2009-01-01

    Genetic studies on model organisms, particularly yeasts and Drosophila melanogaster, have proven powerful in identifying the cell cycle machinery and its regulatory mechanisms. In more recent years RNAi has been used in a variety of genome-wide screens and single molecule studies to elucidate the mechanisms of cell cycle progression. In Drosophila cultured cells, RNAi is extremely simple, and a strong effect can be observed by adding the dsRNA to the cultured cells, with few complications of off-target effects. Functions in cell cycle progression can be followed by a variety of assays. One of the advantages of these cells is that they allow high-resolution spatiotemporal observations to be made by microscopy, with no particular complexity in terms of media and temperature. Here we discuss protocols for RNAi in Drosophila S2 culture cells, followed by the study of mitotic progression, through immunocytochemistry, live imaging, and flow cytometry analysis.

  5. The Cell Cycle Timing of Human Papillomavirus DNA Replication.

    Science.gov (United States)

    Reinson, Tormi; Henno, Liisi; Toots, Mart; Ustav, Mart; Ustav, Mart

    2015-01-01

    Viruses manipulate the cell cycle of the host cell to optimize conditions for more efficient viral genome replication. One strategy utilized by DNA viruses is to replicate their genomes non-concurrently with the host genome; in this case, the viral genome is amplified outside S phase. This phenomenon has also been described for human papillomavirus (HPV) vegetative genome replication, which occurs in G2-arrested cells; however, the precise timing of viral DNA replication during initial and stable replication phases has not been studied. We developed a new method to quantitate newly synthesized DNA levels and used this method in combination with cell cycle synchronization to show that viral DNA replication is initiated during S phase and is extended to G2 during initial amplification but follows the replication pattern of cellular DNA during S phase in the stable maintenance phase. E1 and E2 protein overexpression changes the replication time from S only to both the S and G2 phases in cells that stably maintain viral episomes. These data demonstrate that the active synthesis and replication of the HPV genome are extended into the G2 phase to amplify its copy number and the duration of HPV genome replication is controlled by the level of the viral replication proteins E1 and E2. Using the G2 phase for genome amplification may be an important adaptation that allows exploitation of changing cellular conditions during cell cycle progression. We also describe a new method to quantify newly synthesized viral DNA levels and discuss its benefits for HPV research.

  6. Mast cells dysregulate apoptotic and cell cycle genes in mucosal squamous cell carcinoma

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    Davis Paul

    2006-12-01

    Full Text Available Abstract Background Mucosal squamous cell carcinoma of the head and neck is a disease of high mortality and morbidity. Interactions between the squamous cell carcinoma and the host's local immunity, and how the latter contributes to the biological behavior of the tumor are unclear. In vivo studies have demonstrated sequential mast cell infiltration and degranulation during squamous cell carcinogenesis. The degree of mast cell activation correlates closely with distinct phases of hyperkeratosis, dysplasia, carcinoma in-situ and invasive carcinoma. However, the role of mast cells in carcinogenesis is unclear. Aim This study explores the effects of mast cells on the proliferation and gene expression profile of mucosal squamous cell carcinoma using human mast cell line (HMC-1 and human glossal squamous cell carcinoma cell line (SCC25. Methods HMC-1 and SCC25 were co-cultured in a two-compartment chamber, separated by a polycarbonate membrane. HMC-1 was stimulated to degranulate with calcium ionophore A23187. The experiments were done in quadruplicate. Negative controls were established where SCC25 were cultured alone without HMC-1. At 12, 24, 48 and 72 hours, proliferation and viability of SCC25 were assessed with MTT colorimetric assay. cDNA microarray was employed to study differential gene expression between co-cultured and control SCC25. Results HMC-1/SCC25 co-culture resulted in suppression of growth rate for SCC-25 (34% compared with 110% for the control by 72 hours, p Conclusion We show that mast cells have a direct inhibitory effect on the proliferation of mucosal squamous cell carcinoma in vitro by dysregulating key genes in apoptosis and cell cycle control.

  7. Hippo signaling controls cell cycle and restricts cell plasticity in planarians

    Science.gov (United States)

    de Sousa, Nídia; Rodríguez-Esteban, Gustavo; Rojo-Laguna, Jose Ignacio; Saló, Emili

    2018-01-01

    The Hippo pathway plays a key role in regulating cell turnover in adult tissues, and abnormalities in this pathway are consistently associated with human cancers. Hippo was initially implicated in the control of cell proliferation and death, and its inhibition is linked to the expansion of stem cells and progenitors, leading to larger organ size and tumor formation. To understand the mechanism by which Hippo directs cell renewal and promotes stemness, we studied its function in planarians. These stem cell–based organisms are ideal models for the analysis of the complex cellular events underlying tissue renewal in the whole organism. hippo RNA interference (RNAi) in planarians decreased apoptotic cell death, induced cell cycle arrest, and could promote the dedifferentiation of postmitotic cells. hippo RNAi resulted in extensive undifferentiated areas and overgrowths, with no effect on body size or cell number. We propose an essential role for hippo in controlling cell cycle, restricting cell plasticity, and thereby preventing tumoral transformation. PMID:29357350

  8. A phase synchronization clustering algorithm for identifying interesting groups of genes from cell cycle expression data

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    Tcha Hong

    2008-01-01

    Full Text Available Abstract Background The previous studies of genome-wide expression patterns show that a certain percentage of genes are cell cycle regulated. The expression data has been analyzed in a number of different ways to identify cell cycle dependent genes. In this study, we pose the hypothesis that cell cycle dependent genes are considered as oscillating systems with a rhythm, i.e. systems producing response signals with period and frequency. Therefore, we are motivated to apply the theory of multivariate phase synchronization for clustering cell cycle specific genome-wide expression data. Results We propose the strategy to find groups of genes according to the specific biological process by analyzing cell cycle specific gene expression data. To evaluate the propose method, we use the modified Kuramoto model, which is a phase governing equation that provides the long-term dynamics of globally coupled oscillators. With this equation, we simulate two groups of expression signals, and the simulated signals from each group shares their own common rhythm. Then, the simulated expression data are mixed with randomly generated expression data to be used as input data set to the algorithm. Using these simulated expression data, it is shown that the algorithm is able to identify expression signals that are involved in the same oscillating process. We also evaluate the method with yeast cell cycle expression data. It is shown that the output clusters by the proposed algorithm include genes, which are closely associated with each other by sharing significant Gene Ontology terms of biological process and/or having relatively many known biological interactions. Therefore, the evaluation analysis indicates that the method is able to identify expression signals according to the specific biological process. Our evaluation analysis also indicates that some portion of output by the proposed algorithm is not obtainable by the traditional clustering algorithm with

  9. Cell-cycle research with synchronous cultures: an evaluation

    Science.gov (United States)

    Helmstetter, C. E.; Thornton, M.; Grover, N. B.

    2001-01-01

    The baby-machine system, which produces new-born Escherichia coli cells from cultures immobilized on a membrane, was developed many years ago in an attempt to attain optimal synchrony with minimal disturbance of steady-state growth. In the present article, we put forward a model to describe the behaviour of cells produced by this method, and provide quantitative evaluation of the parameters involved, at each of four different growth rates. Considering the high level of selection achievable with this technique and the natural dispersion in interdivision times, we believe that the output of the baby machine is probably close to optimal in terms of both quality and persistence of synchrony. We show that considerable information on events in the cell cycle can be obtained from populations with age distributions very much broader than those achieved with the baby machine and differing only modestly from steady state. The data presented here, together with the long and fruitful history of findings employing the baby-machine technique, suggest that minimisation of stress on cells is the single most important factor for successful cell-cycle analysis.

  10. Toona Sinensis Extracts Induced Cell Cycle Arrest and Apoptosis in the Human Lung Large Cell Carcinoma

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    Cheng-Yuan Wang

    2010-02-01

    Full Text Available Toona sinensis extracts have been shown to exhibit anti-cancer effects in human ovarian cancer cell lines, human promyelocytic leukemia cells and human lung adenocarcinoma. Its safety has also been confirmed in animal studies. However, its anti-cancer properties in human lung large cell carcinoma have not been studied. Here, we used a powder obtained by freeze-drying the super-natant of centrifuged crude extract from Toona sinensis leaves (TSL-1 to treat the human lung carcinoma cell line H661. Cell viability was evaluated by the 3-(4-,5-dimethylthiazol-2-yl-2,5-diphenyl tetrazolium bromide assay. Flow cytometry analysis revealed that TSL-1 blocked H661 cell cycle progression. Western blot analysis showed decreased expression of cell cycle proteins that promote cell cycle progression, including cyclin-dependent kinase 4 and cyclin D1, and increased the expression of proteins that inhibit cell cycle progression, including p27. Furthermore, flow cytometry analysis showed that TSL-1 induced H661 cell apoptosis. Western blot analysis showed that TSL-1 reduced the expression of the anti-apoptotic protein B-cell lymphoma 2, and degraded the DNA repair protein, poly(ADP-ribose polymerase. TSL-1 shows potential as a novel therapeutic agent or for use as an adjuvant for treating human lung large cell carcinoma.

  11. Molten salt actinide recycler & transforming system and related fuel cycles

    International Nuclear Information System (INIS)

    Ignatiev, V.V.; Feynberg, O.S.

    2015-01-01

    The achievement of a safe, reliable, low waste, flexible, self-sustainable and cheap nuclear power system is the priority task. A study is under progress to examine the feasibility of MOlten Salt Actinide Recycler & Transforming (MOSART) system without and with U-Th support fuelled with different compositions of transuranic elements trifluorides from spent LWR fuel. New design options with homogeneous core and fuel salt with high enough solubility for transuranic elements trifluorides are being examined because of new goals. Consideration is aiming to optimise core neutronic and thermal hydraulic performance, fuel salt / container material, fuel clean up and safety related parameters for MOSART system. Experimental data base created was used for further development of MOSART flowsheet as applied to consumption of transuranic elements trifluorides while extracting their energy. The flexibility of single fluid MOSART concept fuel cycle is underlined, e.g. possibility of its operation in self-sustainable mode using different loadings and feedings. (author)

  12. Pitx2 expression promotes p21 expression and cell cycle exit in neural stem cells.

    Science.gov (United States)

    Heldring, Nina; Joseph, Bertrand; Hermanson, Ola; Kioussi, Chrissa

    2012-11-01

    Cortical development is a complex process that involves many events including proliferation, cell cycle exit and differentiation that need to be appropriately synchronized. Neural stem cells (NSCs) isolated from embryonic cortex are characterized by their ability of self-renewal under continued maintenance of multipotency. Cell cycle progression and arrest during development is regulated by numerous factors, including cyclins, cyclin dependent kinases and their inhibitors. In this study, we exogenously expressed the homeodomain transcription factor Pitx2, usually expressed in postmitotic progenitors and neurons of the embryonic cortex, in NSCs with low expression of endogenous Pitx2. We found that Pitx2 expression induced a rapid decrease in proliferation associated with an accumulation of NSCs in G1 phase. A search for potential cell cycle inhibitors responsible for such cell cycle exit of NSCs revealed that Pitx2 expression caused a rapid and dramatic (≉20-fold) increase in expression of the cell cycle inhibitor p21 (WAF1/Cip1). In addition, Pitx2 bound directly to the p21 promoter as assessed by chromatin immunoprecipitation (ChIP) in NSCs. Surprisingly, Pitx2 expression was not associated with an increase in differentiation markers, but instead the expression of nestin, associated with undifferentiated NSCs, was maintained. Our results suggest that Pitx2 promotes p21 expression and induces cell cycle exit in neural progenitors.

  13. Clustered localization of STAT3 during the cell cycle detected by super-resolution fluorescence microscopy

    Science.gov (United States)

    Gao, Jing; Chen, Junling; Cai, Mingjun; Xu, Haijiao; Jiang, Junguang; Tong, Ti; Wang, Hongda

    2017-06-01

    Signal transducer and activator of transcription 3 (STAT3) plays a key role in various cellular processes such as cell proliferation, differentiation, apoptosis and immune responses. In particular, STAT3 has emerged as a potential molecular target for cancer therapy. The functional role and standard activation mechanism of STAT3 have been well studied, however, the spatial distribution of STAT3 during the cell cycle is poorly known. Therefore, it is indispensable to study STAT3 spatial arrangement and nuclear-cytoplasimic localization at the different phase of cell cycle in cancer cells. By direct stochastic optical reconstruction microscopy imaging, we find that STAT3 forms various number and size of clusters at the different cell-cycle stage, which could not be clearly observed by conventional fluorescent microscopy. STAT3 clusters get more and larger gradually from G1 to G2 phase, during which time transcription and other related activities goes on consistently. The results suggest that there is an intimate relationship between the clustered characteristic of STAT3 and the cell-cycle behavior. Meanwhile, clustering would facilitate STAT3 rapid response to activating signals due to short distances between molecules. Our data might open a new door to develop an antitumor drug for inhibiting STAT3 signaling pathway by destroying its clusters.

  14. Whi7 is an unstable cell-cycle repressor of the Start transcriptional program.

    Science.gov (United States)

    Gomar-Alba, Mercè; Méndez, Ester; Quilis, Inma; Bañó, M Carmen; Igual, J Carlos

    2017-08-24

    Start is the main decision point in eukaryotic cell cycle in which cells commit to a new round of cell division. It involves the irreversible activation of a transcriptional program by G1 CDK-cyclin complexes through the inactivation of Start transcriptional repressors, Whi5 in yeast or Rb in mammals. Here we provide novel keys of how Whi7, a protein related at sequence level to Whi5, represses Start. Whi7 is an unstable protein, degraded by the SCF Grr1 ubiquitin-ligase, whose stability is cell cycle regulated by CDK1 phosphorylation. Importantly, Whi7 associates to G1/S gene promoters in late G1 acting as a repressor of SBF-dependent transcription. Our results demonstrate that Whi7 is a genuine paralog of Whi5. In fact, both proteins collaborate in Start repression bringing to light that yeast cells, as occurs in mammalian cells, rely on the combined action of multiple transcriptional repressors to block Start transition.The commitment of cells to a new cycle of division involves inactivation of the Start transcriptional repressor Whi5. Here the authors show that the sequence related protein Whi7 associates to G1/S gene promoters in late G1 and collaborates with Whi5 in Start repression.

  15. Changes in phosphorus magnetic resonance spectra during the cell cycle of phosphorus limited phased culture of Candida utilis

    International Nuclear Information System (INIS)

    Dawson, P.S.S.; MacDonald, J.C.

    1987-01-01

    Cell extracts, serially obtained from Candida utilis grown in continuous (synchrony) culture under phosphate limitation during an 8-h cycle and examined by NMR spectroscopy, revealed changes in polyphosphate content during the cycle period: other phosphorus containing components showed relatively little change. Initially zero, the polyphosphate content increased rapidly to a maximum after 30 min that coincided with exhaustion of phosphate from the culture, and then decreased slowly back to zero at the end of the cycle. The results suggest that polyphosphate, usually considered to function as a reserve material, actively participates during the cell cycle. 12 refs.; 1 figure; 1 table

  16. Electrofishing power requirements in relation to duty cycle

    Science.gov (United States)

    Miranda, L.E.; Dolan, C.R.

    2004-01-01

    Under controlled laboratory conditions we measured the electrical peak power required to immobilize (i.e., narcotize or tetanize) fish of various species and sizes with duty cycles (i.e., percentage of time a field is energized) ranging from 1.5% to 100%. Electrofishing effectiveness was closely associated with duty cycle. Duty cycles of 10-50% required the least peak power to immobilize fish; peak power requirements increased gradually above 50% duty cycle and sharply below 10%. Small duty cycles can increase field strength by making possible higher instantaneous peak voltages that allow the threshold power needed to immobilize fish to radiate farther away from the electrodes. Therefore, operating within the 10-50% range of duty cycles would allow a larger radius of immobilization action than operating with higher duty cycles. This 10-50% range of duty cycles also coincided with some of the highest margins of difference between the electrical power required to narcotize and that required to tetanize fish. This observation is worthy of note because proper use of duty cycle could help reduce the mortality associated with tetany documented by some authors. Although electrofishing with intermediate duty cycles can potentially increase effectiveness of electrofishing, our results suggest that immobilization response is not fully accounted for by duty cycle because of a potential interaction between pulse frequency and duration that requires further investigation.

  17. Cell death patterns in Arabidopsis cells subjected to four physiological stressors indicate multiple signalling pathways and cell cycle phase specificity.

    Science.gov (United States)

    Pathirana, Ranjith; West, Phillip; Hedderley, Duncan; Eason, Jocelyn

    2017-03-01

    Corpse morphology, nuclear DNA fragmentation, expression of senescence-associated genes (SAG) and cysteine protease profiles were investigated to understand cell death patterns in a cell cycle-synchronised Arabidopsis thaliana cell suspension culture treated with four physiological stressors in the late G2 phase. Within 4 h of treatment, polyethylene glycol (PEG, 20 %), mannose (100 mM) and hydrogen peroxide (2 mM) caused DNA fragmentation coinciding with cell permeability to Evans Blue (EB) and produced corpse morphology corresponding to apoptosis-like programmed cell death (AL-PCD) with cytoplasmic retraction from the cell wall. Ethylene (8 mL per 250-mL flask) caused permeability of cells to EB without concomitant nuclear DNA fragmentation and cytoplasmic retraction, suggesting necrotic cell death. Mannose inducing glycolysis block and PEG causing dehydration resulted in relatively similar patterns of upregulation of SAG suggesting similar cell death signalling pathways for these two stress factors, whereas hydrogen peroxide caused unique patterns indicating an alternate pathway for cell death induced by oxidative stress. Ethylene did not cause appreciable changes in SAG expression, confirming necrotic cell death. Expression of AtDAD, BoMT1 and AtSAG2 genes, previously shown to be associated with plant senescence, also changed rapidly during AL-PCD in cultured cells. The profiles of nine distinct cysteine protease-active bands ranging in size from ca. 21.5 to 38.5 kDa found in the control cultures were also altered after treatment with the four stressors, with mannose and PEG again producing similar patterns. Results also suggest that cysteine proteases may have a role in necrotic cell death.

  18. HERG K+ channel-dependent apoptosis and cell cycle arrest in human glioblastoma cells.

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    Ingo Staudacher

    Full Text Available Glioblastoma (GB is associated with poor patient survival owing to uncontrolled tumor proliferation and resistance to apoptosis. Human ether-a-go-go-related gene K(+ channels (hERG; Kv11.1, KCNH2 are expressed in multiple cancer cells including GB and control cell proliferation and death. We hypothesized that pharmacological targeting of hERG protein would inhibit tumor growth by inducing apoptosis of GB cells. The small molecule hERG ligand doxazosin induced concentration-dependent apoptosis of human LNT-229 (EC50 = 35 µM and U87MG (EC50 = 29 µM GB cells, accompanied by cell cycle arrest in the G0/G1 phase. Apoptosis was associated with 64% reduction of hERG protein. HERG suppression via siRNA-mediated knock down mimicked pro-apoptotic effects of doxazosin. Antagonism of doxazosin binding by the non-apoptotic hERG ligand terazosin resulted in rescue of protein expression and in increased survival of GB cells. At the molecular level doxazosin-dependent apoptosis was characterized by activation of pro-apoptotic factors (phospho-erythropoietin-producing human hepatocellular carcinoma receptor tyrosine kinase A2, phospho-p38 mitogen-activated protein kinase, growth arrest and DNA damage inducible gene 153, cleaved caspases 9, 7, and 3, and by inactivation of anti-apoptotic poly-ADP-ribose-polymerase, respectively. In summary, this work identifies doxazosin as small molecule compound that promotes apoptosis and exerts anti-proliferative effects in human GB cells. Suppression of hERG protein is a crucial molecular event in GB cell apoptosis. Doxazosin and future derivatives are proposed as novel options for more effective GB treatment.

  19. Identification of sugarcane cDNAs encoding components of the cell cycle machinery

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    Andrietta Mírian Helene

    2001-01-01

    Full Text Available Data on cell cycle research in plants indicate that the majority of the fundamental regulators are conserved with other eukaryotes, but the controlling mechanisms imposed on them, and their integration into growth and development is unique to plants. To date, most studies on cell division have been conducted in dicot plants. However, monocot plants have distinct developmental strategies that will affect the regulation of cell division at the meristems. In order to advance our understanding how cell division is integrated with the basic mechanisms controlling cell growth and development in monocots, we took advantage of the sugarcane EST Project (Sucest to carry an exhaustive data mining to identify components of the cell cycle machinery. Results obtained include the description of distinct classes of cyclin-dependent kinases (CDKs; A, B, D, and H-type cyclins; CDK-interacting proteins, CDK-inhibitory and activating kinases, pRB and E2F transcription factors. Most sugarcane cell cycle genes seem to be member of multigene families. Like in dicot plants, CDKa transcription is not restricted to tissues with elevated meristematic activity, but the vast majority of CDKb-related ESTs are found in regions of high proliferation rates. Expression of CKI genes is far more abundant in regions of less cell division, notably in lateral buds. Shared expression patterns for a group of clusters was unraveled by transcriptional profiling, and we suggest that similar approaches could be used to identify genes that are part of the same regulatory network.

  20. Stressing the cell cycle in senescence and aging.

    Science.gov (United States)

    Chandler, Hollie; Peters, Gordon

    2013-12-01

    Senescence represents a permanent exit from the cell cycle and its role in curtailing the proliferation of damaged and potentially oncogenic cells has relevance both as a front-line defense against cancer and as an underlying cause of aging. The retinoblastoma protein (RB) and p53 tumor suppressors are central to the process and the growth arrest is primarily implemented by the cyclin-dependent kinase (CDK) inhibitors, p16INK4a and p21CIP1. In contrast to terminal differentiation, senescence is a general response to a diverse range of cellular stresses and is typically accompanied by a characteristic set of phenotypic changes. Of particular note is a secretory program whose autocrine and paracrine effects can advertize the presence of senescent cells within a tissue and promote their clearance by the immune system. In this short review, we will highlight recent advances in understanding the relationship between senescence and aging and the distinction between senescence and terminal differentiation, from a cell cycle perspective. Copyright © 2013 Elsevier Ltd. All rights reserved.

  1. Cell cycle arrest and biochemical changes accompanying cell death in harmful dinoflagellates following exposure to bacterial algicide IRI-160AA

    Science.gov (United States)

    Pokrzywinski, Kaytee L.; Tilney, Charles L.; Warner, Mark E.; Coyne, Kathryn J.

    2017-03-01

    Bacteria may play a role in regulating harmful algal blooms, but little is known about the biochemical and physiological changes associated with cell death induced by algicidal bacteria. Previous work characterized an algicidal exudate (IRI-160AA) produced by Shewanella sp. IRI-160 that is effective against dinoflagellates, while having little to no effect on other phytoplankton species in laboratory culture experiments. The objective of this study was to evaluate biochemical changes associated with cell death and impacts on the cell cycle in three dinoflagellate species (Prorocentrum minimum, Karlodinium veneficum and Gyrodinium instriatum) after exposure to IRI-160AA. In this study, IRI-160AA induced cell cycle arrest in all dinoflagellates examined. Several indicators for programmed cell death (PCD) that are often observed in phytoplankton in response to a variety of stressors were also evaluated. Cell death was accompanied by significant increases in DNA degradation, intra- and extracellular ROS concentrations and DEVDase (caspase-3 like) protease activity, which have been associated with PCD in other phytoplankton species. Overall, results of this investigation provide strong evidence that treatment with the bacterial algicide, IRI-160AA results in cell cycle arrest and induces biochemical changes consistent with stress-related cell death responses observed in other phytoplankton.

  2. Pfaffosidic Fraction from Hebanthe paniculata Induces Cell Cycle Arrest and Caspase-3-Induced Apoptosis in HepG2 Cells

    Directory of Open Access Journals (Sweden)

    Tereza Cristina da Silva

    2015-01-01

    Full Text Available Hebanthe paniculata roots (formerly Pfaffia paniculata and popularly known as Brazilian ginseng show antineoplastic, chemopreventive, and antiproliferative properties. Functional properties of these roots and their extracts are usually attributed to the pfaffosidic fraction, which is composed mainly by pfaffosides A–F. However, the therapeutic potential of this fraction in cancer cells is not yet entirely understood. This study aimed to analyze the antitumoral effects of the purified pfaffosidic fraction or saponinic fraction on the human hepatocellular carcinoma HepG2 cell line. Cellular viability, proliferation, and apoptosis were evaluated, respectively, by MTT assay, BrdU incorporation, activated caspase-3 immunocytochemistry, and DNA fragmentation assay. Cell cycle was analyzed by flow cytometry and the cell cycle-related proteins were analyzed by quantitative PCR and Western blot. The cells exposed to pfaffosidic fraction had reduced viability and cellular growth, induced G2/M at 48 h or S at 72 h arrest, and increased sub-G1 cell population via cyclin E downregulation, p27KIP1 overexpression, and caspase-3-induced apoptosis, without affecting the DNA integrity. Antitumoral effects of pfaffosidic fraction from H. paniculata in HepG2 cells originated by multimechanisms of action might be associated with cell cycle arrest in the S phase, by CDK2 and cyclin E downregulation and p27KIP1 overexpression, besides induction of apoptosis through caspase-3 activation.

  3. Thermodynamic Analysis of an Integrated Solid Oxide Fuel Cell Cycle with a Rankine Cycle

    DEFF Research Database (Denmark)

    Rokni, Masoud

    2010-01-01

    Hybrid systems consisting of Solid Oxide Fuel Cells (SOFC) on the top of a Steam Turbine (ST) are investigated. The plants are fired by natural gas (NG). A desulfurization reactor removes the sulfur content in the fuel while a pre-reformer breaks down the heavier hydrocarbons. The pre-treated fue......% are achieved which is considerably higher than the conventional Combined Cycles (CC). Both ASR (Adiabatic Steam Reformer) and CPO (Catalytic Partial Oxidation) fuel pre-reformer reactors are considered in this investigation.......Hybrid systems consisting of Solid Oxide Fuel Cells (SOFC) on the top of a Steam Turbine (ST) are investigated. The plants are fired by natural gas (NG). A desulfurization reactor removes the sulfur content in the fuel while a pre-reformer breaks down the heavier hydrocarbons. The pre-treated fuel...

  4. Effect of norcantharidin on the proliferation, apoptosis, and cell cycle of human mesangial cells.

    Science.gov (United States)

    Ye, Kun; Wei, Qiaoyu; Gong, Zhifeng; Huang, Yunfeng; Liu, Hong; Li, Ying; Peng, Xiaomei

    2017-11-01

    Norcantharidin (NCTD) regulates immune system function and reduces proteinuria. We sought to investigate the effect of NCTD on proliferation, apoptosis and cell cycle of cultured human mesangial cells (HMC) in vitro. HMC cells were divided into a normal control group, and various concentrations of NCTD group (2.5, 5, 10, 20, or 40 μg/mL). Cell proliferation was determined by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, apoptosis was detected by Annexin V/propidium iodide (PI) assays, and morphological analysis was performed by Hoechest 33258 staining. Finally, cell cycle was analyzed by flow cytometry. NCTD dose and time dependently inhibits HMC proliferation significantly (p Cell-cycle analysis revealed that the number of cells in the G2 phase increased significantly, whereas the fraction of cells in the S phase decreased, especially 24 h after 5 μg/ml NCTD treatment. NCTD inhibits HMC cell proliferation, induces apoptosis, and affects the cell cycle.

  5. Sub-minute Phosphoregulation of Cell Cycle Systems during Plasmodium Gamete Formation

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    Brandon M. Invergo

    2017-11-01

    Full Text Available Summary: The transmission of malaria parasites to mosquitoes relies on the rapid induction of sexual reproduction upon their ingestion into a blood meal. Haploid female and male gametocytes become activated and emerge from their host cells, and the males enter the cell cycle to produce eight microgametes. The synchronized nature of gametogenesis allowed us to investigate phosphorylation signaling during its first minute in Plasmodium berghei via a high-resolution time course of the phosphoproteome. This revealed an unexpectedly broad response, with proteins related to distinct cell cycle events undergoing simultaneous phosphoregulation. We implicate several protein kinases in the process, and we validate our analyses on the plant-like calcium-dependent protein kinase 4 (CDPK4 and a homolog of serine/arginine-rich protein kinases (SRPK1. Mutants in these kinases displayed distinct phosphoproteomic disruptions, consistent with differences in their phenotypes. The results reveal the central role of protein phosphorylation in the atypical cell cycle regulation of a divergent eukaryote. : Invergo et al. measure a phosphoproteomic time course during a life cycle transition of a malarial parasite. They observed broad phosphoregulation on a sub-minute scale, including simultaneous regulation of replication- and mitosis-related proteins. Their analyses reveal conserved phosphorylation patterns, and they highlight functional roles of specific protein kinases during this process. Keywords: gametogenesis, proteomics, signal transduction, ARK2, CRK5

  6. Simulation of Cell Group Formation Regulated by Coordination Number, Cell Cycle and Duplication Frequency

    Directory of Open Access Journals (Sweden)

    Shigehiro Hashimoto

    2013-08-01

    Full Text Available The effects of coordination number, a cell cycle and duplication frequency on cell-group formation have been investigated in a computer simulation. In the simulation, multiplication occurs in the last three steps of a cell cycle with a probability function to give variations in the interval. Each cell has a constant coordination number: four or six. When a cell gets surrounded by adjacent cells, its status changes from an active stage to a resting stage. Each cell repeats multiplication, and disappears when the times of multiplication reach to the limit. Variation was made in the coordination number, in the interval of multiplication and in the limited times of multiplication. The cells of the colony, which have the larger number of coordination, have reached the larger maximum population and disappeared earlier.

  7. Fuel cycle related parametric study considering long lived actinide production, decay heat and fuel cycle performances

    International Nuclear Information System (INIS)

    Raepsaet, X.; Damian, F.; Lenain, R.; Lecomte, M.

    2001-01-01

    One of the very attractive HTGR reactor characteristics is its highly versatile and flexible core that can fulfil a wide range of diverse fuel cycles. Based on a GTMHR-600 MWth reactor, analyses of several fuel cycles were carried out without taking into account common fuel particle performance limits (burnup, fast fluence, temperature). These values are, however, indicated in each case. Fuel derived from uranium, thorium and a wide variety of plutonium grades has been considered. Long-lived actinide production and total residual decay heat were evaluated for the various types of fuel. The results presented in this papers provide a comparison of the potential and limits of each fuel cycle and allow to define specific cycles offering lowest actinide production and residual heat associated with a long life cycle. (author)

  8. Prp19 Arrests Cell Cycle via Cdc5L in Hepatocellular Carcinoma Cells

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    Renzheng Huang

    2017-04-01

    Full Text Available Pre-mRNA processing factor 19 (Prp19 is involved in many cellular events including pre-mRNA processing and DNA damage response. Recently, it has been identified as a candidate oncogene in hepatocellular carcinoma (HCC. However, the role of Prp19 in tumor biology is still elusive. Here, we reported that Prp19 arrested cell cycle in HCC cells via regulating G2/M transition. Mechanistic insights revealed that silencing Prp19 inhibited the expression of cell division cycle 5-like (Cdc5L via repressing the translation of Cdc5L mRNA and facilitating lysosome-mediated degradation of Cdc5L in HCC cells. Furthermore, we found that silencing Prp19 induced cell cycle arrest could be partially resumed by overexpressing Cdc5L. This work implied that Prp19 participated in mitotic progression and thus could be a promising therapeutic target of HCC.

  9. Sulforaphane induces cell cycle arrest and apoptosis in acute lymphoblastic leukemia cells.

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    Koramit Suppipat

    Full Text Available Acute lymphoblastic leukemia (ALL is the most common hematological cancer in children. Although risk-adaptive therapy, CNS-directed chemotherapy, and supportive care have improved the survival of ALL patients, disease relapse is still the leading cause of cancer-related death in children. Therefore, new drugs are needed as frontline treatments in high-risk disease and as salvage agents in relapsed ALL. In this study, we report that purified sulforaphane, a natural isothiocyanate found in cruciferous vegetables, has anti-leukemic properties in a broad range of ALL cell lines and primary lymphoblasts from pediatric T-ALL and pre-B ALL patients. The treatment of ALL leukemic cells with sulforaphane resulted in dose-dependent apoptosis and G2/M cell cycle arrest, which was associated with the activation of caspases (3, 8, and 9, inactivation of PARP, p53-independent upregulation of p21(CIP1/WAF1, and inhibition of the Cdc2/Cyclin B1 complex. Interestingly, sulforaphane also inhibited the AKT and mTOR survival pathways in most of the tested cell lines by lowering the levels of both total and phosphorylated proteins. Finally, the administration of sulforaphane to the ALL xenograft models resulted in a reduction of tumor burden, particularly following oral administration, suggesting a potential role as an adjunctive agent to improve the therapeutic response in high-risk ALL patients with activated AKT signaling.

  10. Cell cycle dependency of 67gallium uptake and cytotoxicity in human cell lines of hematological malignancies.

    Science.gov (United States)

    Van Leeuwen-Stok, E A; Jonkhoff, A R; Visser-Platier, A W; Dräger, L M; Teule, G J; Huijgens, P C; Schuurhuis, G J

    1998-11-01

    67Gallium (67Ga) is a radionuclide which accumulates in hematological malignancies and is used for diagnostic imaging. We investigated in this in vitro study the cell cycle dependency of cellular uptake and cytotoxicity of 67Ga. Cell cycle synchronization of cells was achieved by counterflow centrifugal elutriation and the use of cytostatic drugs. The human lymphoma cell lines U-937 and U-715 were used and in elutriation experiments we also used the leukemic cell line HL-60. The transferrin receptor (CD71) expression, 67Ga uptake and cell proliferation inhibition were the parameters measured. We also studied cytotoxicity in various schedules for combination of 67Ga and drugs and the residual proliferative capacity was measured. The CD71 expression in the three cell lines increased from 106-177% on S phase cells and from 118-233% on G2M cells, as compared to the G0/G1 cell fraction. The 67Ga uptake varied from 108-127% for S cells and 128-139% for G2M cells. The drugs chosen induced cell cycle phase accumulation in S and/or G2M phase during preincubation. 67Ga preincubation induced accumulation in the G2M phase. Almost all combinations of 67Ga and drugs resulted in a non-interactive effect, except for methotrexate which resulted in an antagonistic effect. No preferential effect of any of the incubation schemes was seen. CD71 expression and 67Ga uptake were increased in S and G2M cells. Combination of 67Ga with drugs which arrest cells in these cell cycle phases did not result in a change in cytotoxicity. However, these results implicate that 67Ga and the cytostatic drugs tested except for methotrexate might be used together or sequentially in therapy.

  11. Protective effect of deoxyribonucleosides on UV-irradiated human peripheral blood T-lymphocytes: possibilities for the selective killing of either cycling or non-cycling cells.

    Science.gov (United States)

    Green, M H; Waugh, A P; Lowe, J E; Harcourt, S A; Clingen, P H; Cole, J; Arlett, C F

    1996-02-19

    Non-cycling human T-lymphocytes from normal subjects show a 10-fold greater sensitivity than fibroblasts to UV-B (280-315 nm) irradiation from a Westinghouse FS20 lamp, but only a 2.7-fold greater sensitivity to UV-C (254 nm) irradiation. Hypersensitivity is associated with a deficiency in the rejoining of excision breaks. Non-cycling T-lymphocytes have extremely low deoxyribonucleotide pools. Addition to the medium of the four deoxyribonucleosides, each at a concentration of 10(-5) M, substantially increases survival and reduces the persistence of excision-related strand breaks following UV-B or UV-C irradiation (Yew and Johnson (1979) Biochim. Biophys. Acta 562, 240-241; Green et al. (1994) Mutation Res., 315, 25-32). UV-resistance of T-lymphocytes is also increased by stimulating the cells into cycle. The addition of deoxyribonucleosides does not further enhance survival of cycling cells and they do not reach the level of resistance achieved by non-cycling cells in the presence of deoxyribonucleosides. We suggest that two opposing effects are in operation. Cells out of cycle can show increased resistance to DNA damage in the absence of division but they also have reduced deoxyribonucleotide pools, which may limit DNA repair. With UV-B irradiation, the exceptionally low dNTP pools in non-cycling T-lymphocytes cause this second effect to predominate. In contrast, with ionising radiation, which forms highly cytotoxic double-strand breaks, non-cycling human T-lymphocytes are slightly more resistant than fibroblasts. Non-cycling cells such as T-lymphocytes should be especially sensitive to agents which produce a high proportion of read excisable damage, but should show normal resistance to agents which highly toxic lesions. It may be possible by choice of DNA damaging agent and manipulation of cellular deoxyribonucleotide pools, to choose regimes which will selectively kill either cycling or non-cycling cells and to improve the efficacy of standard therapeutic

  12. Curcumin Induces Autophagy, Apoptosis, and Cell Cycle Arrest in Human Pancreatic Cancer Cells

    Directory of Open Access Journals (Sweden)

    Yaping Zhu

    2017-01-01

    Full Text Available Objective. Curcumin is an active extract from turmeric. The aim of this study was to identify the underlying mechanism of curcumin on PCa cells and the role of autophagy in this process. Methods. The inhibitory effect of curcumin on the growth of PANC1 and BxPC3 cell lines was detected by CCK-8 assay. Cell cycle distribution and apoptosis were tested by flow cytometry. Autophagosomes were tested by cell immunofluorescence assay. The protein expression was detected by Western blot. The correlation between LC3II/Bax and cell viability was analyzed. Results. Curcumin inhibited the cell proliferation in a dose- and time-dependent manner. Curcumin could induce cell cycle arrest at G2/M phase and apoptosis of PCa cells. The autophagosomes were detected in the dosing groups. Protein expression of Bax and LC3II was upregulated, while Bcl2 was downregulated in the high dosing groups of curcumin. There was a significant negative correlation between LC3II/Bax and cell viability. Conclusions. Autophagy could be triggered by curcumin in the treatment of PCa. Apoptosis and cell cycle arrest also participated in this process. These findings imply that curcumin is a multitargeted agent for PCa cells. In addition, autophagic cell death may predominate in the high concentration groups of curcumin.

  13. American cranberry (Vaccinium macrocarpon) extract affects human prostate cancer cell growth via cell cycle arrest by modulating expression of cell cycle regulators.

    Science.gov (United States)

    Déziel, Bob; MacPhee, James; Patel, Kunal; Catalli, Adriana; Kulka, Marianna; Neto, Catherine; Gottschall-Pass, Katherine; Hurta, Robert

    2012-05-01

    Prostate cancer is one of the most common cancers in the world, and its prevalence is expected to increase appreciably in the coming decades. As such, more research is necessary to understand the etiology, progression and possible preventative measures to delay or to stop the development of this disease. Recently, there has been interest in examining the effects of whole extracts from commonly harvested crops on the behaviour and progression of cancer. Here, we describe the effects of whole cranberry extract (WCE) on the behaviour of DU145 human prostate cancer cells in vitro. Following treatment of DU145 human prostate cancer cells with 10, 25 and 50 μg ml⁻¹ of WCE, respectively for 6 h, WCE significantly decreased the cellular viability of DU145 cells. WCE also decreased the proportion of cells in the G2-M phase of the cell cycle and increased the proportion of cells in the G1 phase of the cell cycle following treatment of cells with 25 and 50 μg ml⁻¹ treatment of WCE for 6 h. These alterations in cell cycle were associated with changes in cell cycle regulatory proteins and other cell cycle associated proteins. WCE decreased the expression of CDK4, cyclin A, cyclin B1, cyclin D1 and cyclin E, and increased the expression of p27. Changes in p16(INK4a) and pRBp107 protein expression levels also were evident, however, the changes noted in p16(INK4a) and pRBp107 protein expression levels were not statistically significant. These findings demonstrate that phytochemical extracts from the American cranberry (Vaccinium macrocarpon) can affect the behaviour of human prostate cancer cells in vitro and further support the potential health benefits associated with cranberries.

  14. Stable Regulation of Cell Cycle Events in Mycobacteria: Insights From Inherently Heterogeneous Bacterial Populations

    Science.gov (United States)

    Logsdon, Michelle M.; Aldridge, Bree B.

    2018-01-01

    Model bacteria, such as E. coli and B. subtilis, tightly regulate cell cycle progression to achieve consistent cell size distributions and replication dynamics. Many of the hallmark features of these model bacteria, including lateral cell wall elongation and symmetric growth and division, do not occur in mycobacteria. Instead, mycobacterial growth is characterized by asymmetric polar growth and division. This innate asymmetry creates unequal birth sizes and growth rates for daughter cells with each division, generating a phenotypically heterogeneous population. Although the asymmetric growth patterns of mycobacteria lead to a larger variation in birth size than typically seen in model bacterial populations, the cell size distribution is stable over time. Here, we review the cellular mechanisms of growth, division, and cell cycle progression in mycobacteria in the face of asymmetry and inherent heterogeneity. These processes coalesce to control cell size. Although Mycobacterium smegmatis and Mycobacterium bovis Bacillus Calmette-Guérin (BCG) utilize a novel model of cell size control, they are similar to previously studied bacteria in that initiation of DNA replication is a key checkpoint for cell division. We compare the regulation of DNA replication initiation and strategies used for cell size homeostasis in mycobacteria and model bacteria. Finally, we review the importance of cellular organization and chromosome segregation relating to the physiology of mycobacteria and consider how new frameworks could be applied across the wide spectrum of bacterial diversity. PMID:29619019

  15. On climatic changes related to the 22-year solar cycle

    Science.gov (United States)

    Schuurmans, C. J. E.

    1974-01-01

    The 22-year or double sunspot cycle as a cause for longitudinal displacements of atmospheric semi-permanent centers of action is studied. A difference in frequency of occurence of Icelandic lows between the two halves of the double sunspot cycle during winter seasons is found.

  16. HCdc14A is involved in cell cycle regulation of human brain vascular endothelial cells following injury induced by high glucose, free fatty acids and hypoxia.

    Science.gov (United States)

    Su, Jingjing; Zhou, Houguang; Tao, Yinghong; Guo, Zhuangli; Zhang, Shuo; Zhang, Yu; Huang, Yanyan; Tang, Yuping; Hu, Renming; Dong, Qiang

    2015-01-01

    Cell cycle processes play a vital role in vascular endothelial proliferation and dysfunction. Cell division cycle protein 14 (Cdc14) is an important cell cycle regulatory phosphatase. Previous studies in budding yeast demonstrated that Cdc14 could trigger the inactivation of mitotic cyclin-dependent kinases (Cdks), which are required for mitotic exit and cytokinesis. However, the exact function of human Cdc14 (hCdc14) in cell cycle regulation during vascular diseases is yet to be elucidated. There are two HCdc14 homologs: hCdc14A and hCdc14B. In the current study, we investigated the potential role of hCdc14A in high glucose-, free fatty acids (FFAs)-, and hypoxia-induced injury in cultured human brain vascular endothelial cells (HBVECs). Data revealed that high glucose, FFA, and hypoxia down-regulated hCdc14A expression remarkably, and also affected the expression of other cell cycle-related proteins such as cyclin B, cyclin D, cyclin E, and p53. Furthermore, the combined addition of the three stimuli largely blocked cell cycle progression, decreased cell proliferation, and increased apoptosis. We also determined that hCdc14A was localized mainly to centrosomes during interphase and spindles during mitosis using confocal microscopy, and that it could affect the expression of other cycle-related proteins. More importantly, the overexpression of hCdc14A accelerated cell cycle progression, enhanced cell proliferation, and promoted neoplastic transformation, whereas the knockdown of hCdc14A using small interfering RNA produced the opposite effects. Therefore, these findings provide novel evidence that hCdc14A might be involved in cell cycle regulation in cultured HBVECs during high glucose-, FFA-, and hypoxia-induced injury. Copyright © 2014 Elsevier Inc. All rights reserved.

  17. Large-Scale Analysis of CRISPR/Cas9 Cell-Cycle Knockouts Reveals the Diversity of p53-Dependent Responses to Cell-Cycle Defects.

    Science.gov (United States)

    McKinley, Kara L; Cheeseman, Iain M

    2017-02-27

    Defining the genes that are essential for cellular proliferation is critical for understanding organismal development and identifying high-value targets for disease therapies. However, the requirements for cell-cycle progression in human cells remain incompletely understood. To elucidate the consequences of acute and chronic elimination of cell-cycle proteins, we generated and characterized inducible CRISPR/Cas9 knockout human cell lines targeting 209 genes involved in diverse cell-cycle processes. We performed single-cell microscopic analyses to systematically establish the effects of the knockouts on subcellular architecture. To define variations in cell-cycle requirements between cultured cell lines, we generated knockouts across cell lines of diverse origins. We demonstrate that p53 modulates the phenotype of specific cell-cycle defects through distinct mechanisms, depending on the defect. This work provides a resource to broadly facilitate robust and long-term depletion of cell-cycle proteins and reveals insights into the requirements for cell-cycle progression. Copyright © 2017 Elsevier Inc. All rights reserved.

  18. Refined life-cycle assessment of polymer solar cells

    DEFF Research Database (Denmark)

    Lenzmann, F.; Kroon, J.; Andriessen, R.

    2011-01-01

    A refined life-cycle assessment of polymer solar cells is presented with a focus on critical components, i.e. the transparent conductive ITO layer and the encapsulation components. This present analysis gives a comprehensive sketch of the full environmental potential of polymer-OPV in comparison...... with other PV technologies. It is shown that on a m2 basis the environmental characteristics of polymer-OPV are highly beneficial, while on a watt-peak and on a kWh basis, these benefits are - at the current level of the development - still (over-)compensated by low module efficiency and limited lifetime...

  19. Maid (GCIP) is involved in cell cycle control of hepatocytes

    DEFF Research Database (Denmark)

    Sonnenberg-Riethmacher, Eva; Wüstefeld, Torsten; Miehe, Michaela

    2007-01-01

    . Therefore, we studied the role of Maid during cell cycle progression after partial hepatectomy (PH). Lack of Maid expression after PH was associated with a delay in G1/S-phase progression as evidenced by delayed cyclinA expression and DNA replication in Maid-deficient mice. However, at later time points......The function of Maid (GCIP), a cyclinD-binding helix-loop-helix protein, was analyzed by targeted disruption in mice. We show that Maid function is not required for normal embryonic development. However, older Maid-deficient mice-in contrast to wild-type controls--develop hepatocellular carcinomas...

  20. INTEGRATED GASIFICATION COMBINED CYCLE PROJECT 2 MW FUEL CELL DEMONSTRATION

    Energy Technology Data Exchange (ETDEWEB)

    FuelCell Energy

    2005-05-16

    With about 50% of power generation in the United States derived from coal and projections indicating that coal will continue to be the primary fuel for power generation in the next two decades, the Department of Energy (DOE) Clean Coal Technology Demonstration Program (CCTDP) has been conducted since 1985 to develop innovative, environmentally friendly processes for the world energy market place. The 2 MW Fuel Cell Demonstration was part of the Kentucky Pioneer Energy (KPE) Integrated Gasification Combined Cycle (IGCC) project selected by DOE under Round Five of the Clean Coal Technology Demonstration Program. The participant in the CCTDP V Project was Kentucky Pioneer Energy for the IGCC plant. FuelCell Energy, Inc. (FCE), under subcontract to KPE, was responsible for the design, construction and operation of the 2 MW fuel cell power plant. Duke Fluor Daniel provided engineering design and procurement support for the balance-of-plant skids. Colt Engineering Corporation provided engineering design, fabrication and procurement of the syngas processing skids. Jacobs Applied Technology provided the fabrication of the fuel cell module vessels. Wabash River Energy Ltd (WREL) provided the test site. The 2 MW fuel cell power plant utilizes FuelCell Energy's Direct Fuel Cell (DFC) technology, which is based on the internally reforming carbonate fuel cell. This plant is capable of operating on coal-derived syngas as well as natural gas. Prior testing (1992) of a subscale 20 kW carbonate fuel cell stack at the Louisiana Gasification Technology Inc. (LGTI) site using the Dow/Destec gasification plant indicated that operation on coal derived gas provided normal performance and stable operation. Duke Fluor Daniel and FuelCell Energy developed a commercial plant design for the 2 MW fuel cell. The plant was designed to be modular, factory assembled and truck shippable to the site. Five balance-of-plant skids incorporating fuel processing, anode gas oxidation, heat recovery

  1. Centrosome/Cell cycle uncoupling and elimination in the endoreduplicating intestinal cells of C. elegans.

    Science.gov (United States)

    Lu, Yu; Roy, Richard

    2014-01-01

    The centrosome cycle is most often coordinated with mitotic cell division through the activity of various essential cell cycle regulators, consequently ensuring that the centriole is duplicated once, and only once, per cell cycle. However, this coupling can be altered in specific developmental contexts; for example, multi-ciliated cells generate hundreds of centrioles without any S-phase requirement for their biogenesis, while Drosophila follicle cells eliminate their centrosomes as they begin to endoreduplicate. In order to better understand how the centrosome cycle and the cell cycle are coordinated in a developmental context we use the endoreduplicating intestinal cell lineage of C. elegans to address how novel variations of the cell cycle impact this important process. In C. elegans, the larval intestinal cells undergo one nuclear division without subsequent cytokinesis, followed by four endocycles that are characterized by successive rounds of S-phase. We monitored the levels of centriolar/centrosomal markers and found that centrosomes lose their pericentriolar material following the nuclear division that occurs during the L1 stage and is thereafter never re-gained. The centrioles then become refractory to S phase regulators that would normally promote duplication during the first endocycle, after which they are eliminated during the L2 stage. Furthermore, we show that SPD-2 plays a central role in the numeral regulation of centrioles as a potential target of CDK activity. On the other hand, the phosphorylation on SPD-2 by Polo-like kinase, the transcriptional regulation of genes that affect centriole biogenesis, and the ubiquitin/proteasome degradation pathway, contribute collectively to the final elimination of the centrioles during the L2 stage.

  2. Centrosome/Cell cycle uncoupling and elimination in the endoreduplicating intestinal cells of C. elegans.

    Directory of Open Access Journals (Sweden)

    Yu Lu

    Full Text Available The centrosome cycle is most often coordinated with mitotic cell division through the activity of various essential cell cycle regulators, consequently ensuring that the centriole is duplicated once, and only once, per cell cycle. However, this coupling can be altered in specific developmental contexts; for example, multi-ciliated cells generate hundreds of centrioles without any S-phase requirement for their biogenesis, while Drosophila follicle cells eliminate their centrosomes as they begin to endoreduplicate. In order to better understand how the centrosome cycle and the cell cycle are coordinated in a developmental context we use the endoreduplicating intestinal cell lineage of C. elegans to address how novel variations of the cell cycle impact this important process. In C. elegans, the larval intestinal cells undergo one nuclear division without subsequent cytokinesis, followed by four endocycles that are characterized by successive rounds of S-phase. We monitored the levels of centriolar/centrosomal markers and found that centrosomes lose their pericentriolar material following the nuclear division that occurs during the L1 stage and is thereafter never re-gained. The centrioles then become refractory to S phase regulators that would normally promote duplication during the first endocycle, after which they are eliminated during the L2 stage. Furthermore, we show that SPD-2 plays a central role in the numeral regulation of centrioles as a potential target of CDK activity. On the other hand, the phosphorylation on SPD-2 by Polo-like kinase, the transcriptional regulation of genes that affect centriole biogenesis, and the ubiquitin/proteasome degradation pathway, contribute collectively to the final elimination of the centrioles during the L2 stage.

  3. Remote sensing of wetland parameters related to carbon cycling

    Science.gov (United States)

    Bartlett, David S.; Johnson, Robert W.

    1985-01-01

    Measurement of the rates of important biogeochemical fluxes on regional or global scales is vital to understanding the geochemical and climatic consequences of natural biospheric processes and of human intervention in those processes. Remote data gathering and interpretation techniques were used to examine important cycling processes taking place in wetlands over large geographic expanses. Large area estimation of vegetative biomass and productivity depends upon accurate, consistent measurements of canopy spectral reflectance and upon wide applicability of algorithms relating reflectance to biometric parameters. Results of the use of airborne multispectral scanner data to map above-ground biomass in a Delaware salt marsh are shown. The mapping uses an effective algorithm linking biomass to measured spectral reflectance and a means to correct the scanner data for large variations in the angle of observation of the canopy. The consistency of radiometric biomass algorithms for marsh grass when they are applied over large latitudinal and tidal range gradients were also examined. Results of a 1 year study of methane emissions from tidal wetlands along a salinity gradient show marked effects of temperature, season, and pore-water chemistry in mediating flux to the atmosphere.

  4. Robust synchronization of coupled circadian and cell cycle oscillators in single mammalian cells

    Science.gov (United States)

    Bieler, Jonathan; Cannavo, Rosamaria; Gustafson, Kyle; Gobet, Cedric; Gatfield, David; Naef, Felix

    2014-01-01

    Circadian cycles and cell cycles are two fundamental periodic processes with a period in the range of 1 day. Consequently, coupling between such cycles can lead to synchronization. Here, we estimated the mutual interactions between the two oscillators by time-lapse imaging of single mammalian NIH3T3 fibroblasts during several days. The analysis of thousands of circadian cycles in dividing cells clearly indicated that both oscillators tick in a 1:1 mode-locked state, with cell divisions occurring tightly 5 h before the peak in circadian Rev-Erbα-YFP reporter expression. In principle, such synchrony may be caused by either unidirectional or bidirectional coupling. While gating of cell division by the circadian cycle has been most studied, our data combined with stochastic modeling unambiguously show that the reverse coupling is predominant in NIH3T3 cells. Moreover, temperature, genetic, and pharmacological perturbations showed that the two interacting cellular oscillators adopt a synchronized state that is highly robust over a wide range of parameters. These findings have implications for circadian function in proliferative tissues, including epidermis, immune cells, and cancer. PMID:25028488

  5. Increasing water cycle extremes in California and in relation to ENSO cycle under global warming

    OpenAIRE

    Yoon, Jin-Ho; Wang, S-Y Simon; Gillies, Robert R.; Kravitz, Ben; Hipps, Lawrence; Rasch, Philip J.

    2015-01-01

    Since the winter of 2013–2014, California has experienced its most severe drought in recorded history, causing statewide water stress, severe economic loss and an extraordinary increase in wildfires. Identifying the effects of global warming on regional water cycle extremes, such as the ongoing drought in California, remains a challenge. Here we analyse large-ensemble and multi-model simulations that project the future of water cycle extremes in California as well as to understand those assoc...

  6. Ni-YSZ solid oxide fuel cell anode behavior upon redox cycling based on electrical characterization

    DEFF Research Database (Denmark)

    Klemensø, Trine; Mogensen, Mogens Bjerg

    2006-01-01

    Ni-YSZ cermets are a prevalent material used for solid oxide fuel cells. However, the cermet degrades upon redox cycling. The degradation is related to microstructural changes, but knowledge of the mechanisms has been limited. DC conductivity measurements were performed on cermets and cermets......, where the Ni component was removed, before, during and after redox cycling the cermet. The cermet conductivity degraded over time due to sintering of the nickel phase. Following oxidizing events, the conductivity of the cermets improved, whereas the conductivity of the YSZ phase decreased. A model...

  7. Ni-YSZ solid oxide fuel cell anode behavior upon redox cycling based on electrical characterization

    DEFF Research Database (Denmark)

    Klemensø, Trine; Mogensen, Mogens Bjerg

    2007-01-01

    Nickel (Ni)—yttria-stabilized zirconia (YSZ) cermets are a prevalent material used for solid oxide fuel cells. The cermet degrades upon redox cycling. The degradation is related to microstructural changes, but knowledge of the mechanisms has been limited. Direct current conductivity measurements...... were performed on cermets and cermets where the Ni component was removed. Measurements were carried out before, during, and after redox cycling the cermet. The cermet conductivity degraded over time due to sintering of the nickel phase. Following oxidizing events, the conductivity of the cermets...

  8. Effect of particle irradiation on cell cycle progression

    Energy Technology Data Exchange (ETDEWEB)

    Eguchi, Kiyomi [National Inst. of Radiological Sciences, Chiba (Japan); Ohara, Hiroshi

    1997-02-01

    We studied effects of fractionated exposure of heavy ion beams with high linear energy transfer (LET). Asynchronous V79 cells were irradiated by He-3 or C ion beam at cyclotron at NIRS (12 MeV/u, LET{approx_equal} 20-250 keV/{mu}m). Extent of recovery of sublethal damage (SLDR) decreased with increasing LET. At the highest LET tested, the enhancement of cell killing (potentiation) was observed. Flow cytometry data showed the more efficient accumulation of cells at a G2/M phase at 4 h after irradiation by high LET particle beams than by X-rays. This potentiation might be caused by partial synchronization at a cell cycle position (s) where cells are sensitive to heavy ion exposure. When carbon ion beam with spread-out Bragg peak (SBP) at the RIKEN Ring Cyclotron (initial energy=135 MeV/u) were split into 2 equal exposure at 12-hr-interval, SLDR was observed at the entrance of the beam. In contrast, little recovery was observed at middle or distal peak positions. These results showed the benefits of carbon ion beam for cancer therapy, because we can expect some recovery in normal tissue at entrance of the beam, whereas no recovery in tumor at SBP. (author)

  9. Loratadine dysregulates cell cycle progression and enhances the effect of radiation in human tumor cell lines

    International Nuclear Information System (INIS)

    Soule, Benjamin P; Simone, Nicole L; DeGraff, William G; Choudhuri, Rajani; Cook, John A; Mitchell, James B

    2010-01-01

    The histamine receptor-1 (H1)-antagonist, loratadine has been shown to inhibit growth of human colon cancer xenografts in part due to cell cycle arrest in G2/M. Since this is a radiation sensitive phase of the cell cycle, we sought to determine if loratadine modifies radiosensitivity in several human tumor cell lines with emphasis on human colon carcinoma (HT29). Cells were treated with several doses of loratadine at several time points before and after exposure to radiation. Radiation dose modifying factors (DMF) were determined using full radiation dose response survival curves. Cell cycle phase was determined by flow cytometry and the expression of the cell cycle-associated proteins Chk1, pChk1 ser345 , and Cyclin B was analyzed by western blot. Loratadine pre-treatment of exponentially growing cells (75 μM, 24 hours) increased radiation-induced cytotoxicity yielding a radiation DMF of 1.95. However, treatment of plateau phase cells also yielded a DMF of 1.3 suggesting that mechanisms other than cell cycle arrest also contribute to loratadine-mediated radiation modification. Like irradiation, loratadine initially induced G2/M arrest and activation of the cell-cycle associated protein Chk1 to pChk1 ser345 , however a subsequent decrease in expression of total Chk1 and Cyclin B correlated with abrogation of the G2/M checkpoint. Analysis of DNA repair enzyme expression and DNA fragmentation revealed a distinct pattern of DNA damage in loratadine-treated cells in addition to enhanced radiation-induced damage. Taken together, these data suggest that the observed effects of loratadine are multifactorial in that loratadine 1) directly damages DNA, 2) activates Chk1 thereby promoting G2/M arrest making cells more susceptible to radiation-induced DNA damage and, 3) downregulates total Chk1 and Cyclin B abrogating the radiation-induced G2/M checkpoint and allowing cells to re-enter the cell cycle despite the persistence of damaged DNA. Given this unique possible

  10. Loratadine dysregulates cell cycle progression and enhances the effect of radiation in human tumor cell lines

    Directory of Open Access Journals (Sweden)

    Cook John A

    2010-02-01

    Full Text Available Abstract Background The histamine receptor-1 (H1-antagonist, loratadine has been shown to inhibit growth of human colon cancer xenografts in part due to cell cycle arrest in G2/M. Since this is a radiation sensitive phase of the cell cycle, we sought to determine if loratadine modifies radiosensitivity in several human tumor cell lines with emphasis on human colon carcinoma (HT29. Methods Cells were treated with several doses of loratadine at several time points before and after exposure to radiation. Radiation dose modifying factors (DMF were determined using full radiation dose response survival curves. Cell cycle phase was determined by flow cytometry and the expression of the cell cycle-associated proteins Chk1, pChk1ser345, and Cyclin B was analyzed by western blot. Results Loratadine pre-treatment of exponentially growing cells (75 μM, 24 hours increased radiation-induced cytotoxicity yielding a radiation DMF of 1.95. However, treatment of plateau phase cells also yielded a DMF of 1.3 suggesting that mechanisms other than cell cycle arrest also contribute to loratadine-mediated radiation modification. Like irradiation, loratadine initially induced G2/M arrest and activation of the cell-cycle associated protein Chk1 to pChk1ser345, however a subsequent decrease in expression of total Chk1 and Cyclin B correlated with abrogation of the G2/M checkpoint. Analysis of DNA repair enzyme expression and DNA fragmentation revealed a distinct pattern of DNA damage in loratadine-treated cells in addition to enhanced radiation-induced damage. Taken together, these data suggest that the observed effects of loratadine are multifactorial in that loratadine 1 directly damages DNA, 2 activates Chk1 thereby promoting G2/M arrest making cells more susceptible to radiation-induced DNA damage and, 3 downregulates total Chk1 and Cyclin B abrogating the radiation-induced G2/M checkpoint and allowing cells to re-enter the cell cycle despite the persistence of

  11. IAEA Activities in the Area of Fast Reactors and Related Fuels and Fuel Cycles

    International Nuclear Information System (INIS)

    Monti, S.; Basak, U.; Dyck, G.; Inozemtsev, V.; Toti, A.; Zeman, A.

    2013-01-01

    Summary: • The IAEA role to support fast reactors and associated fuel cycle development programmes; • Main IAEA activities on fast reactors and related fuel and fuel cycle technology; • Main IAEA deliverables on fast reactors and related fuel and fuel cycle technology

  12. Nek1 silencing slows down DNA repair and blocks DNA damage-induced cell cycle arrest.

    Science.gov (United States)

    Pelegrini, Alessandra Luíza; Moura, Dinara Jaqueline; Brenner, Bethânia Luise; Ledur, Pitia Flores; Maques, Gabriela Porto; Henriques, João Antônio Pegas; Saffi, Jenifer; Lenz, Guido

    2010-09-01

    Never in mitosis A (NIMA)-related kinases (Nek) are evolutionarily conserved proteins structurally related to the Aspergillus nidulans mitotic regulator NIMA. Nek1 is one of the 11 isoforms of the Neks identified in mammals. Different lines of evidence suggest the participation of Nek1 in response to DNA damage, which is also supported by the interaction of this kinase with proteins involved in DNA repair pathways and cell cycle regulation. In this report, we show that cells with Nek1 knockdown (KD) through stable RNA interference present a delay in DNA repair when treated with methyl-methanesulfonate (MMS), hydrogen peroxide (H(2)O(2)) and cisplatin (CPT). In particular, interstrand cross links induced by CPT take much longer to be resolved in Nek1 KD cells when compared to wild-type (WT) cells. In KD cells, phosphorylation of Chk1 in response to CPT was strongly reduced. While WT cells accumulate in G(2)/M after DNA damage with MMS and H(2)O(2), Nek1 KD cells do not arrest, suggesting that G(2)/M arrest induced by the DNA damage requires Nek1. Surprisingly, CPT-treated Nek1 KD cells arrest with a 4N DNA content similar to WT cells. This deregulation in cell cycle control in Nek1 KD cells leads to an increased sensitivity to genotoxic agents when compared to WT cells. These results suggest that Nek1 is involved in the beginning of the cellular response to genotoxic stress and plays an important role in preventing cell death induced by DNA damage.

  13. Analysis of redox relationships in the plant cell cycle: determinations of ascorbate, glutathione and poly (ADPribose)polymerase (PARP) in plant cell cultures.

    Science.gov (United States)

    Foyer, Christine H; Pellny, Till K; Locato, Vittoria; De Gara, Laura

    2008-01-01

    Reactive oxygen species (ROS) and low molecular weight antioxidants, such as glutathione and ascorbate, are powerful signaling molecules that participate in the control of plant growth and development, and modulate progression through the mitotic cell cycle. Enhanced reactive oxygen species accumulation or low levels of ascorbate or glutathione cause the cell cycle to arrest and halt progression especially through the G1 checkpoint. Plant cell suspension cultures have proved to be particularly useful tools for the study of cell cycle regulation. Here we provide effective and accurate methods for the measurement of changes in the cellular ascorbate and glutathione pools and the activities of related enzymes such poly (ADP-ribose) polymerase during mitosis and cell expansion, particularly in cell suspension cultures. These methods can be used in studies seeking to improve current understanding of the roles of redox controls on cell division and cell expansion.

  14. The Analysis of Cell Cycle, Proliferation, and Asymmetric Cell Division by Imaging Flow Cytometry.

    Science.gov (United States)

    Filby, Andrew; Day, William; Purewal, Sukhveer; Martinez-Martin, Nuria

    2016-01-01

    Measuring cellular DNA content by conventional flow cytometry (CFC) and fluorescent DNA-binding dyes is a highly robust method for analysing cell cycle distributions within heterogeneous populations. However, any conclusions drawn from single-parameter DNA analysis alone can often be confounded by the asynchronous nature of cell proliferation. We have shown that by combining fluorescent DNA stains with proliferation tracking dyes and antigenic staining for mitotic cells one can elucidate the division history and cell cycle position of any cell within an asynchronously dividing population. Furthermore if one applies this panel to an imaging flow cytometry (IFC) system then the spatial information allows resolution of the four main mitotic phases and the ability to study molecular distributions within these populations. We have employed such an approach to study the prevalence of asymmetric cell division (ACD) within activated immune cells by measuring the distribution of key fate determining molecules across the plane of cytokinesis in a high-throughput, objective, and internally controlled manner. Moreover the ability to perform high-resolution, temporal dissection of the cell division process lends itself perfectly to investigating the influence chemotherapeutic agents exert on the proliferative capacity of transformed cell lines. Here we describe the method in detail and its application to both ACD and general cell cycle analysis.

  15. Daughter-cell-specific modulation of nuclear pore complexes controls cell cycle entry during asymmetric division.

    Science.gov (United States)

    Kumar, Arun; Sharma, Priyanka; Gomar-Alba, Mercè; Shcheprova, Zhanna; Daulny, Anne; Sanmartín, Trinidad; Matucci, Irene; Funaya, Charlotta; Beato, Miguel; Mendoza, Manuel

    2018-04-01

    The acquisition of cellular identity is coupled to changes in the nuclear periphery and nuclear pore complexes (NPCs). Whether and how these changes determine cell fate remain unclear. We have uncovered a mechanism that regulates NPC acetylation to direct cell fate after asymmetric division in budding yeast. The lysine deacetylase Hos3 associates specifically with daughter cell NPCs during mitosis to delay cell cycle entry (Start). Hos3-dependent deacetylation of nuclear basket and central channel nucleoporins establishes daughter-cell-specific nuclear accumulation of the transcriptional repressor Whi5 during anaphase and perinuclear silencing of the G1/S cyclin gene CLN2 in the following G1 phase. Hos3-dependent coordination of both events restrains Start in daughter, but not in mother, cells. We propose that deacetylation modulates transport-dependent and transport-independent functions of NPCs, leading to differential cell cycle progression in mother and daughter cells. Similar mechanisms might regulate NPC functions in specific cell types and/or cell cycle stages in multicellular organisms.

  16. Change of cell cycle arrest of tumor cell lines after 60Co γ-irradiation

    International Nuclear Information System (INIS)

    Tang Yi; Liu Wenli; Zhou Jianfeng; Gao Qinglei; Wu Jianhong

    2003-01-01

    Objective: To observe the cell cycle arrest changes in peripheral blood mononuclear cells (PBMNCs) of normal persons and several kinds of tumor cell lines after 60 Co γ-irradiation. Methods: PBMNCs of normal persons, HL-60, K562, SiHA and 113 tumor cell lines were irradiated with 60 Co γ-rays at the absorbed doses of 6, 10,15 Gy. Cell cycles changes were checked 6, 12, 24, 48 and 60 h after the irradiation. Results: A stasis state was observed in normal person PBMNCs, 95 percents of which were in G 1 phase, and they still remained stasis after the irradiation. Except the 113 cell line manifesting G 1 phase arrest, all other tumor cell lines showed G 2 /M phase arrest after irradiation. The radiation sensitivity of HL-60 was higher than that of SiHA cell line. Conclusion: Different cell lines have different cell cycle arrest reaction to radiation and their radiation sensitivity are also different

  17. Andrographolide induces cell cycle arrest at G2/M phase and cell death in HepG2 cells via alteration of reactive oxygen species.

    Science.gov (United States)

    Li, Jieliang; Cheung, Hon-Yeung; Zhang, Zhiqiang; Chan, Gallant K L; Fong, Wang-Fun

    2007-07-30

    The cytotoxicity of andrographolide to HepG2 human hepatoma cells was investigated in the present study. Growth of HepG2 cells was affected in the presence of andrographolide with an IC(50) of 40.2 microM after 48 h treatment. Flow cytometric analysis and DNA fragmentation assay revealed that andrographolide induced cell cycle arrest at G2/M phase and a late apoptosis of the cells. The occurrence of cell cycle arrest was accompanied by the collapse of mitochondrial membrane potential (MMP) and an intracellular increase of hydrogen peroxide (H(2)O(2)) but a decrease of superoxide radicals (O(2)(-)) and reduced glutathione. In the treated cells, expression of Bax as well as the transcriptional controller of this pro-apoptotic gene, p53, was upregulated but not other apoptotic proteins such as Bad, Bcl-2 and Bcl-X(L). Although the activity of caspase-3, which has direct effect on apoptosis, was also enhanced by the presence of andrographolide, cell death of HepG2 could neither be prevented by a specific inhibitor of capsase-3 nor the pan-caspase inhibitor-zVAD (Val-Ala-Asp), indicating that it was a caspase-independent cell death. Since the overall percentage of apoptotic cells was relatively small throughout the experimental studies, we conclude that the cytotoxic effect of andrographolide on HepG2 cells is primary attributed to the induction of cell cycle arrest via the alteration of cellular redox status.

  18. Timing robustness in the budding and fission yeast cell cycles.

    KAUST Repository

    Mangla, Karan

    2010-02-01

    Robustness of biological models has emerged as an important principle in systems biology. Many past analyses of Boolean models update all pending changes in signals simultaneously (i.e., synchronously), making it impossible to consider robustness to variations in timing that result from noise and different environmental conditions. We checked previously published mathematical models of the cell cycles of budding and fission yeast for robustness to timing variations by constructing Boolean models and analyzing them using model-checking software for the property of speed independence. Surprisingly, the models are nearly, but not totally, speed-independent. In some cases, examination of timing problems discovered in the analysis exposes apparent inaccuracies in the model. Biologically justified revisions to the model eliminate the timing problems. Furthermore, in silico random mutations in the regulatory interactions of a speed-independent Boolean model are shown to be unlikely to preserve speed independence, even in models that are otherwise functional, providing evidence for selection pressure to maintain timing robustness. Multiple cell cycle models exhibit strong robustness to timing variation, apparently due to evolutionary pressure. Thus, timing robustness can be a basis for generating testable hypotheses and can focus attention on aspects of a model that may need refinement.

  19. Gankyrin, the 26 S proteasome, the cell cycle and cancer.

    Science.gov (United States)

    Mayer, R J; Fujita, J

    2006-11-01

    The known molecular players in cell-cycle control are much studied, not only to learn more about this intricate system, but also to understand the molecular features of oncogenic transformation. Infrequently, new players are discovered that change the interpretation of cell-cycle control. Gankyrin is one such player and was discovered in yeast two-hybrid screens as a new proteasomal subunit that interacts specifically with the S6b (rpt3) AAA (ATPase associated with various cellular activities) ATPase, which, with five other AAAs, are present in the so-called base of the 19 S regulator of the 26 S proteasome. Gankyrin is also the first liver oncogene. Gankyrin is found in other complexes that contain Rb (retinoblastoma protein) and the ubiquitin protein ligase Mdm2 (murine double minute 2). Gankyrin increases the hyperphosphorylation of Rb and therefore activates E2F-dependent transcription of DNA synthesis genes. Additionally, gankyrin, by binding to Mdm2, increases the ubiquitylation and degradation of p53 and prevents apoptosis. Gankyrin controls the functions of two major tumour suppressors and, when overexpressed, causes hepatocellular carcinoma.

  20. TIMP-3 recruits quiescent hematopoietic stem cells into active cell cycle and expands multipotent progenitor pool.

    Science.gov (United States)

    Nakajima, Hideaki; Ito, Miyuki; Smookler, David S; Shibata, Fumi; Fukuchi, Yumi; Morikawa, Yoshihiro; Ikeda, Yuichi; Arai, Fumio; Suda, Toshio; Khokha, Rama; Kitamura, Toshio

    2010-11-25

    Regulating transition of hematopoietic stem cells (HSCs) between quiescent and cycling states is critical for maintaining homeostasis of blood cell production. The cycling states of HSCs are regulated by the extracellular factors such as cytokines and extracellular matrix; however, the molecular circuitry for such regulation remains elusive. Here we show that tissue inhibitor of metalloproteinase-3 (TIMP-3), an endogenous regulator of metalloproteinases, stimulates HSC proliferation by recruiting quiescent HSCs into the cell cycle. Myelosuppression induced TIMP-3 in the bone marrow before hematopoietic recovery. Interestingly, TIMP-3 enhanced proliferation of HSCs and promoted expansion of multipotent progenitors, which was achieved by stimulating cell-cycle entry of quiescent HSCs without compensating their long-term repopulating activity. Surprisingly, this effect did not require metalloproteinase inhibitory activity of TIMP-3 and was possibly mediated through a direct inhibition of angiopoietin-1 signaling, a critical mediator for HSC quiescence. Furthermore, bone marrow recovery from myelosuppression was accelerated by over-expression of TIMP-3, and in turn, impaired in TIMP-3-deficient animals. These results suggest that TIMP-3 may act as a molecular cue in response to myelosuppression for recruiting dormant HSCs into active cell cycle and may be clinically useful for facilitating hematopoietic recovery after chemotherapy or ex vivo expansion of HSCs.

  1. Sphingosine 1-phosphate regulates proliferation, cell cycle and apoptosis of hepatocellular carcinoma cells via syndecan-1.

    Science.gov (United States)

    Zeng, Ye; Liu, Xiaoheng; Yan, Zhiping; Xie, Linshen

    2017-11-24

    Sphingosine 1-phosphate (S1P) plays an important role in hepatocarcinogenesis. We previously demonstrated that S1P induced epithelial-mesenchymal transition of hepatocellular carcinoma (HCC) cells via an MMP-7/Syndecan-1/TGF-β autocrine loop. In the present study, we investigated the regulative role of S1P in cell survival and progression of HCC cells, and tested whether syndecan-1 is required in the S1P action. After transfected with syndecan-1 shRNA, HepG2 and SMMC7721 cells were treated with S1P for 72 h, and then cell proliferation was detected by CCK8 assay, and cell cycle progression and cell apoptosis were detected by flow cytometry. The levels of apoptosis markers including cleaved-Caspase-3 and cleaved-PARP in SMMC7721 cells were examined by western blotting. Results showed that S1P significantly enhanced cell proliferation in HCC cells, which was significantly inhibited by syndecan-1 shRNA. S1P induced the cell proportion in S phase in HCC cells, whereas S1P decreased the proportion of cells in both early and late apoptosis. Syndecan-1 shRNA induced the G2/M arrest in the presence of S1P. In the syndecan-1 shRNA transfected HCC cells, the proportions of late and early apoptotic cells, and levels of cleaved-Caspase-3 and cleaved-PARP were significantly increased in cells with or without S1P treatment. Thus, S1P augments the proportion of cells in S phase of the cell cycle that might translate to enhance HCC cell proliferation and inhibit the cell apoptosis via syndecan-1. Copyright © 2017 Elsevier Ltd. All rights reserved.

  2. SPARC expression induces cell cycle arrest via STAT3 signaling pathway in medulloblastoma cells

    Energy Technology Data Exchange (ETDEWEB)

    Chetty, Chandramu [Department of Cancer Biology and Pharmacology, University of Illinois College of Medicine at Peoria, One Illini Drive, Peoria, IL-61605 (United States); Dontula, Ranadheer [Section of Hematology/Oncology, Department of Medicine, University of Illinois College of Medicine at Chicago, 840 South Wood Street, Suite 820-E, Chicago, IL-60612 (United States); Ganji, Purnachandra Nagaraju [Department of Cancer Biology and Pharmacology, University of Illinois College of Medicine at Peoria, One Illini Drive, Peoria, IL-61605 (United States); Gujrati, Meena [Department of Pathology, University of Illinois College of Medicine at Peoria, One Illini Drive, Peoria, IL-61605 (United States); Lakka, Sajani S., E-mail: slakka@uic.edu [Section of Hematology/Oncology, Department of Medicine, University of Illinois College of Medicine at Chicago, 840 South Wood Street, Suite 820-E, Chicago, IL-60612 (United States)

    2012-01-13

    Highlights: Black-Right-Pointing-Pointer Ectopic expression of SPARC impaired cell proliferation in medulloblastoma cells. Black-Right-Pointing-Pointer SPARC expression induces STAT3 mediated cell cycle arrest in medulloblastoma cells. Black-Right-Pointing-Pointer SPARC expression significantly inhibited pre-established tumor growth in nude-mice. -- Abstract: Dynamic cell interaction with ECM components has profound influence in cancer progression. SPARC is a component of the ECM, impairs the proliferation of different cell types and modulates tumor cell aggressive features. We previously reported that SPARC expression significantly impairs medulloblastoma tumor growth in vivo. In this study, we demonstrate that expression of SPARC inhibits medulloblastoma cell proliferation. MTT assay indicated a dose-dependent reduction in tumor cell proliferation in adenoviral mediated expression of SPARC full length cDNA (Ad-DsRed-SP) in D425 and UW228 cells. Flow cytometric analysis showed that Ad-DsRed-SP-infected cells accumulate in the G2/M phase of cell cycle. Further, immunoblot and immunoprecipitation analyses revealed that SPARC induced G2/M cell cycle arrest was mediated through inhibition of the Cyclin-B-regulated signaling pathway involving p21 and Cdc2 expression. Additionally, expression of SPARC decreased STAT3 phosphorylation at Tyr-705; constitutively active STAT3 expression reversed SPARC induced G2/M arrest. Ad-DsRed-SP significantly inhibited the pre-established orthotopic tumor growth and tumor volume in nude-mice. Immunohistochemical analysis of tumor sections from mice treated with Ad-DsRed-SP showed decreased immunoreactivity for pSTAT3 and increased immunoreactivity for p21 compared to tumor section from mice treated with mock and Ad-DsRed. Taken together our studies further reveal that STAT3 plays a key role in SPARC induced G2/M arrest in medulloblastoma cells. These new findings provide a molecular basis for the mechanistic understanding of the

  3. AIB1 regulates the ovarian cancer cell cycle through TUG1.

    Science.gov (United States)

    Li, L; Gan, Z-H; Qin, L; Jiao, S-H; Shi, Y

    2017-12-01

    To explore the mechanism of amplified in breast cancer 1 (AIB1) to promote ovarian cancer progress. Cor correlation analysis was performed to obtain the top 100 lncRNAs that were positively correlated with AIB1. The relationship of taurine upregulated gene 1 (TUG1) and clinicopathological characteristics. Moreover, Gene Ontology (GO) and Gene Set Enrichment Analysis (GSEA) were performed to predict the biological process where TUG1 may be involved in. At last, Cell Counting Kit-8 (CCK-8), colon formation and flow cytometry were conducted to explore the biological process that TUG1 may influence. Meanwhile, Western blot was performed to explore the mechanism of TUG1. In this study, it was found that P73 antisense RNA 1T (TP73-AS1), LINC00654 and TUG1 had the tumor-promoting effect in the top 100 lncRNAs that were positively correlated with AIB1. The expression level of TUG1 was significantly decreased after intervention of AIB1. Then, the clinical data were analyzed and the results showed that TUG1 was related to the tumor residue, tumor staging, tumor grade and lymph node metastasis. Moreover, the bioinformatics analysis revealed that TUG1 was mainly involved in the regulation of cell cycle. After intervention in TUG1, it was found that the cell proliferation capacity was significantly decreased, and the cell cycle was arrested in G1 phase. Finally, Western blot revealed that the expressions of G1 phase-related proteins were significantly changed. This study indicated that AIB1 regulates the cycle of ovarian cancer cells through TUG1. This study proved that AIB1 can regulate the cell cycle through regulating TUG1.

  4. Casticin impairs cell growth and induces cell apoptosis via cell cycle arrest in human oral cancer SCC-4 cells.

    Science.gov (United States)

    Chou, Guan-Ling; Peng, Shu-Fen; Liao, Ching-Lung; Ho, Heng-Chien; Lu, Kung-Wen; Lien, Jin-Cherng; Fan, Ming-Jen; La, Kuang-Chi; Chung, Jing-Gung

    2018-02-01

    Casticin, a polymethoxyflavone, present in natural plants, has been shown to have biological activities including anti-cancer activities. Herein, we investigated the anti-oral cancer activity of casticin on SCC-4 cells in vitro. Viable cells, cell cycle distribution, apoptotic cell death, reactive oxygen species (ROS) production, and Ca 2+ production, levels of ΔΨ m and caspase activity were measured by flow cytometric assay. Cell apoptosis associated protein expressions were examined by Western blotting and confocal laser microscopy. Results indicated that casticin induced cell morphological changes, DNA condensation and damage, decreased the total viable cells, induced G 2 /M phase arrest in SCC-4 cells. Casticin promoted ROS and Ca 2+ productions, decreases the levels of ΔΨ m , promoted caspase-3, -8, and -9 activities in SCC-4 cells. Western blotting assay demonstrated that casticin affect protein level associated with G2/M phase arrest and apoptosis. Confocal laser microscopy also confirmed that casticin increased the translocation of AIF and cytochrome c in SCC-4 cells. In conclusion, casticin decreased cell number through G 2 /M phase arrest and the induction of cell apoptosis through caspase- and mitochondria-dependent pathways in SCC-4 cells. © 2017 Wiley Periodicals, Inc.

  5. Controlling kinase activity during the cell cycle: from the DNA damage response to mitosis

    NARCIS (Netherlands)

    Bruinsma, W.

    2014-01-01

    The cell cycle is the process through which cells execute cell division. This is essential for many basal processes such as organismal development, tissue maintenance and reproduction. Disruption of the cell cycle, for example by damaged DNA, can have vast consequences and can lead to many diseases

  6. ATR Kinase Inhibition Protects Non-cycling Cells from the Lethal Effects of DNA Damage and Transcription Stress*

    Science.gov (United States)

    Kemp, Michael G.; Sancar, Aziz

    2016-01-01

    ATR (ataxia telangiectasia and Rad-3-related) is a protein kinase that maintains genome stability and halts cell cycle phase transitions in response to DNA lesions that block DNA polymerase movement. These DNA replication-associated features of ATR function have led to the emergence of ATR kinase inhibitors as potential adjuvants for DNA-damaging cancer chemotherapeutics. However, whether ATR affects the genotoxic stress response in non-replicating, non-cycling cells is currently unknown. We therefore used chemical inhibition of ATR kinase activity to examine the role of ATR in quiescent human cells. Although ATR inhibition had no obvious effects on the viability of non-cycling cells, inhibition of ATR partially protected non-replicating cells from the lethal effects of UV and UV mimetics. Analyses of various DNA damage response signaling pathways demonstrated that ATR inhibition reduced the activation of apoptotic signaling by these agents in non-cycling cells. The pro-apoptosis/cell death function of ATR is likely due to transcription stress because the lethal effects of compounds that block RNA polymerase movement were reduced in the presence of an ATR inhibitor. These results therefore suggest that whereas DNA polymerase stalling at DNA lesions activates ATR to protect cell viability and prevent apoptosis, the stalling of RNA polymerases instead activates ATR to induce an apoptotic form of cell death in non-cycling cells. These results have important implications regarding the use of ATR inhibitors in cancer chemotherapy regimens. PMID:26940878

  7. Piperine causes G1 phase cell cycle arrest and apoptosis in melanoma cells through checkpoint kinase-1 activation.

    Directory of Open Access Journals (Sweden)

    Neel M Fofaria

    Full Text Available In this study, we determined the cytotoxic effects of piperine, a major constituent of black and long pepper in melanoma cells. Piperine treatment inhibited the growth of SK MEL 28 and B16 F0 cells in a dose and time-dependent manner. The growth inhibitory effects of piperine were mediated by cell cycle arrest of both the cell lines in G1 phase. The G1 arrest by piperine correlated with the down-regulation of cyclin D1 and induction of p21. Furthermore, this growth arrest by piperine treatment was associated with DNA damage as indicated by phosphorylation of H2AX at Ser139, activation of ataxia telangiectasia and rad3-related protein (ATR and checkpoint kinase 1 (Chk1. Pretreatment with AZD 7762, a Chk1 inhibitor not only abrogated the activation of Chk1 but also piperine mediated G1 arrest. Similarly, transfection of cells with Chk1 siRNA completely protected the cells from G1 arrest induced by piperine. Piperine treatment caused down-regulation of E2F1 and phosphorylation of retinoblastoma protein (Rb. Apoptosis induced by piperine was associated with down-regulation of XIAP, Bid (full length and cleavage of Caspase-3 and PARP. Furthermore, our results showed that piperine treatment generated ROS in melanoma cells. Blocking ROS by tiron protected the cells from piperine mediated cell cycle arrest and apoptosis. These results suggest that piperine mediated ROS played a critical role in inducing DNA damage and activation of Chk1 leading to G1 cell cycle arrest and apoptosis.

  8. Discovery of a Splicing Regulator Required for Cell Cycle Progression

    Energy Technology Data Exchange (ETDEWEB)

    Suvorova, Elena S.; Croken, Matthew; Kratzer, Stella; Ting, Li-Min; Conde de Felipe, Magnolia; Balu, Bharath; Markillie, Lye Meng; Weiss, Louis M.; Kim, Kami; White, Michael W.

    2013-02-01

    In the G1 phase of the cell division cycle, eukaryotic cells prepare many of the resources necessary for a new round of growth including renewal of the transcriptional and protein synthetic capacities and building the machinery for chromosome replication. The function of G1 has an early evolutionary origin and is preserved in single and multicellular organisms, although the regulatory mechanisms conducting G1 specific functions are only understood in a few model eukaryotes. Here we describe a new G1 mutant from an ancient family of apicomplexan protozoans. Toxoplasma gondii temperature-sensitive mutant 12-109C6 conditionally arrests in the G1 phase due to a single point mutation in a novel protein containing a single RNA-recognition-motif (TgRRM1). The resulting tyrosine to asparagine amino acid change in TgRRM1 causes severe temperature instability that generates an effective null phenotype for this protein when the mutant is shifted to the restrictive temperature. Orthologs of TgRRM1 are widely conserved in diverse eukaryote lineages, and the human counterpart (RBM42) can functionally replace the missing Toxoplasma factor. Transcriptome studies demonstrate that gene expression is downregulated in the mutant at the restrictive temperature due to a severe defect in splicing that affects both cell cycle and constitutively expressed mRNAs. The interaction of TgRRM1 with factors of the tri-SNP complex (U4/U6 & U5 snRNPs) indicate this factor may be required to assemble an active spliceosome. Thus, the TgRRM1 family of proteins is an unrecognized and evolutionarily conserved class of splicing regulators. This study demonstrates investigations into diverse unicellular eukaryotes, like the Apicomplexa, have the potential to yield new insights into important mechanisms conserved across modern eukaryotic kingdoms.

  9. Mechanisms involved in alternariol-induced cell cycle arrest

    Energy Technology Data Exchange (ETDEWEB)

    Solhaug, A., E-mail: Anita.Solhaug@vetinst.no [Norwegian Veterinary Institute, Oslo (Norway); Vines, L.L. [Michigan State University, Department of Food Science and Human Nutrition, East Lansing, MI (United States); Ivanova, L.; Spilsberg, B. [Norwegian Veterinary Institute, Oslo (Norway); Holme, J.A. [Norwegian Institute of Public Health, Division of Environmental Medicine, Oslo (Norway); Pestka, J. [Michigan State University, Department of Food Science and Human Nutrition, East Lansing, MI (United States); Collins, A. [University of Oslo, Department of Nutrition, Faculty of Medicine, Oslo (Norway); Eriksen, G.S. [Norwegian Veterinary Institute, Oslo (Norway)

    2012-10-15

    Alternariol (AOH), a mycotoxin produced by Alternaria sp, is often found as a contaminant in fruit and cereal products. Here we employed the murine macrophage cell line RAW 264.7 to test the hypothesis that AOH causes toxicity as a response to DNA damage. AOH at concentrations of 15-30 {mu}M almost completely blocked cell proliferation. Within 30 min treatment, AOH (30 {mu}M) significantly increased the level of reactive oxygen species (ROS). Furthermore, DNA base oxidations as well as DNA strand breaks and/or alkaline labile sites were detected by the comet assay after 2 h exposure of AOH. Cell death (mostly necrosis) was observed after prolonged exposure to the highest concentration of AOH (60 {mu}M for 24 and 48 h) in our study. The DNA damage response involved phosphorylation (activation) of histone H2AX and check point kinase-1- and 2 (Chk-1/2). Moreover, AOH activated p53 and increased the expression of p21, Cyclin B, MDM2, and Sestrin 2; likewise the level of several miRNA was affected. AOH-induced Sestrin 2 expression was regulated by p53 and could at least partly be inhibited by antioxidants, suggesting a role of ROS in the response. Interestingly, the addition of antioxidants did not inhibit cell cycle arrest. Although the formation of ROS by itself was not directly linked cell proliferation, AOH-induced DNA damage and resulting transcriptional changes in p21, MDM2, and Cyclin B likely contribute to the reduced cell proliferation; while Sestrin 2 would contribute to the oxidant defense.

  10. Simulation of the Prokaryotic Cell Cycle at http://simon.bio.uva.nl/cellcycle/

    Directory of Open Access Journals (Sweden)

    Arieh Zaritsky

    2012-02-01

    Full Text Available The bacterial Cell Cycle is presented using the Simulation program CCSim, which employs four parameters related to time (inter-division τ, replication C, division D and size (mass at replication initiation Mi, sufficient to describe and compare bacterial cells under various conditions. The parameter values can be altered and the effects of the alterations can be seen. CCSim is easy to use and presents the kinetics of cell growth in a digestible format. Replicating chromosomes and growing bacillary cells are coupled to parameters that affect the cell cycle and animated. It serves as an educational tool to teach bacteriology and to compare experimental observations with the model best describing cell growth thus improve our understanding of regulatory mechanisms. Examples are displayed of transitions between known physiological states that are consistent with experimental results, including one that explains strange observations. The program predicts enhanced division frequencies after a period of slow replication under thymine limitation if a minimal distance (Eclipse exists between successive replisomes, as observed. Missing features and ways to improve, extend and refine CCSim are proposed, for both single cells and random populations under steady-states of exponential growth and during well-defined transitions. Future improvements and extensions are proposed for single cells and populations.

  11. Simulation of the Prokaryotic Cell Cycle at simon.bio.uva.nl/cellcycle/

    Directory of Open Access Journals (Sweden)

    Charles E. Helmstetter

    2012-02-01

    Full Text Available The bacterial Cell Cycle is presented using the Simulation program CCSim, which employs four parameters related to time (inter-division τ, replication C, division D and size (mass at replication initiation Mi, sufficient to describe and compare bacterial cells under various conditions. The parameter values can be altered and the effects of the alterations can be seen. CCSim is easy to use and presents the kinetics of cell growth in a digestible format. Replicating chromosomes and growing bacillary cells are coupled to parameters that affect the cell cycle and animated. It serves as an educational tool to teach bacteriology and to compare experimental observations with the model best describing cell growth thus improve our understanding of regulatory mechanisms. Examples are displayed of transitions between known physiological states that are consistent with experimental results, including one that explains strange observations. The program predicts enhanced division frequencies after a period of slow replication under thymine limitation if a minimal distance (Eclipse exists between successive replisomes, as observed. Missing features and ways to improve, extend and refine CCSim are proposed, for both single cells and random populations under steady-states of exponential growth and during well-defined transitions. Future improvements and extensions are proposed for single cells and populations.

  12. Butyrate induces reactive oxygen species production and affects cell cycle progression in human gingival fibroblasts.

    Science.gov (United States)

    Chang, M-C; Tsai, Y-L; Chen, Y-W; Chan, C-P; Huang, C-F; Lan, W-C; Lin, C-C; Lan, W-H; Jeng, J-H

    2013-02-01

    Short-chain fatty acids, such as butyric acid and propionic acid, are metabolic by-products generated by periodontal microflora such as Porphyromonas gingivalis, and contribute to the pathogenesis of periodontitis. However, the effects of butyrate on the biological activities of gingival fibroblasts (GFs) are not well elucidated. Human GFs were exposed to various concentrations of butyrate (0.5-16 mm) for 24 h. Viable cells that excluded trypan blue were counted. Cell cycle distribution of GFs was analyzed by propidium iodide-staining flow cytometry. Cellular reactive oxygen species (ROS) production was measured by flow cytometry using 2',7'-dichlorofluorescein (DCF). Total RNA and protein lysates were isolated and subjected to RT-PCR using specific primers or to western blotting using specific antibodies, respectively. Butyrate inhibited the growth of GFs, as indicated by a decrease in the number of viable cells. This event was associated with an induction of G0/G1 and G2/M cell cycle arrest by butyrate (4-16 mm) in GFs. However, no marked apoptosis of GFs was noted in this experimental condition. Butyrate (> 2 mm) inhibited the expression of cdc2, cdc25C and cyclinB1 mRNAs and reduced the levels of Cdc2, Cdc25C and cyclinB1 proteins in GFs, as determined using RT-PCR and western blotting, respectively. This toxic effect of butyrate was associated with the production of ROS. These results suggest that butyrate generated by periodontal pathogens may be involved in the pathogenesis of periodontal diseases via the induction of ROS production and the impairment of cell growth, cell cycle progression and expression of cell cycle-related genes in GFs. These events are important in the initiation and prolongation of inflammatory processes in periodontal diseases. © 2012 John Wiley & Sons A/S.

  13. Cell-cycle-dependent regulation of cell motility and determination of the role of Rac1

    DEFF Research Database (Denmark)

    Walmod, Peter S.; Hartmann-Petersen, Rasmus; Prag, S.

    2004-01-01

    was accompanied by changes in morphology reflecting the larger volume of cells in G2 than in G1. Furthermore, L-cells and HeLa-cells appeared to be less adherent in the G2 phase. Transfection of L-cells with constitutively active Rac1 led to a general increase in the speed and rate of diffusion in G2 to levels...... comparable to those of control cells in G1. In contrast, transfection with dominant-negative Rac1 reduced cell speed and resulted in cellular displacements, which were identical in G1 and G2. These observations indicate that migration of cultured cells is regulated in a cell-cycle-dependent manner......, and that an enhancement of Rac1 activity is sufficient for a delay of the reduced cell displacement otherwise seen in G2....

  14. S100 protein expression in human melanoma cells: Comparison of levels of expression among different cell lines and individual cells in different phases of the cell cycle

    Energy Technology Data Exchange (ETDEWEB)

    Marks, A.; O' Hanlon, D.; Dunn, R. (Univ. of Toronto, Ontario (Canada)); Petsche, D.; Baumal, R. (Hospital for Sick Children, Toronto, Ontario (Canada)); Kwong, P.C.; Stead, R. (McMaster Univ., Hamilton, Ontario (Canada)); Liao, S.K. (McMaster Univ., Hamilton, Ontario (Canada) Biotherapeutics, Inc., Franklin, TN (United States))

    1990-03-01

    The synthesis of S100 protein in cultured human melanoma cells was examined using metabolic labeling with ({sup 35}S)methionine, immunoprecipitation with anti-S100 protein antiserum, and polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulfate. Six of seven cell lines derived from melanomas synthesized relatively large amounts of S100 protein, whereas three cell lines derived from normal melanocytes synthesized lesser amounts. Synthesis of S100 protein was not detected in 10 human cell lines of non-neuroectodermal origin. Analysis of poly(A{sup +}) RNA form one melanoma cell line by Northern blot hybridization with a probe specific for the {beta} subunit of rat S100 protein revealed a single mRNA species of 1.0 kb coding for the human protein. Flow cytometric analysis of individual cells of two melanoma cell lines and the rat glioma cell line C6 indicated that G0/G1 cells were heterogeneous with respect to S100 protein expression, while almost all the cells in S+G2+M expressed S100 protein. These results suggest that expression of S100 protein in G0/G1 could be a prerequisite for progression of the cells through the cell cycle.

  15. Impaired germ cell development due to compromised cell cycle progression in Skp2-deficient mice

    Directory of Open Access Journals (Sweden)

    Nakayama Keiko

    2006-04-01

    Full Text Available Abstract Background The gonads are responsible for the production of germ cells through both mitosis and meiosis. Skp2 is the receptor subunit of an SCF-type ubiquitin ligase and is a major regulator of the progression of cells into S phase of the cell cycle, which it promotes by mediating the ubiquitin-dependent degradation of p27, an inhibitor of cell proliferation. However, the role of the Skp2-p27 pathway in germ cell development remains elusive. Results We now show that disruption of Skp2 in mice results in a marked impairment in the fertility of males, with the phenotypes resembling Sertoli cell-only syndrome in men. Testes of Skp2-/- mice manifested pronounced germ cell hypoplasia accompanied by massive apoptosis in spermatogenic cells. Flow cytometry revealed an increased prevalence of polyploidy in spermatozoa, suggesting that the aneuploidy of these cells is responsible for the induction of apoptosis. Disruption of the p27 gene of Skp2-/- mice restored germ cell development, indicating that the testicular hypoplasia of Skp2-/- animals is attributable to the antiproliferative effect of p27 accumulation. Conclusion Our results thus suggest that compromised cell cycle progression caused by the accumulation of p27 results in aneuploidy and the induction of apoptosis in gonadal cells of Skp2-/- mice. The consequent reduction in the number of mature gametes accounts for the decreased fertility of these animals. These findings reinforce the importance of the Skp2-p27 pathway in cell cycle regulation and in germ cell development.

  16. Downregulation of HDAC9 inhibits cell proliferation and tumor formation by inducing cell cycle arrest in retinoblastoma

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Yiting; Wu, Dan; Xia, Fengjie; Xian, Hongyu; Zhu, Xinyue [Medical School of Nanjing University, Department of Ophthalmology, Jinling Hospital, Nanjing, 210002 (China); Cui, Hongjuan, E-mail: hcui@swu.edu.cn [State Key Laboratory of Silkworm Genome Biology, Institute of Sericulture and Systems Biology, Southwest University, Chongqing, 400716 (China); Huang, Zhenping, E-mail: huangzhenping19633@163.com [Medical School of Nanjing University, Department of Ophthalmology, Jinling Hospital, Nanjing, 210002 (China)

    2016-04-29

    Histone deacetylase 9 (HDAC9) is a member of class II HDACs, which regulates a wide variety of normal and abnormal physiological functions. Recently, HDAC9 has been found to be overexpressed in some types of human cancers. However, the role of HDAC9 in retinoblastoma remains unclear. In this study, we found that HDAC9 was commonly expressed in retinoblastoma tissues and HDAC9 was overexpressed in prognostically poor retinoblastoma patients. Through knocking down HDAC9 in Y79 and WERI-Rb-1 cells, the expression level of HDAC9 was found to be positively related to cell proliferation in vitro. Further investigation indicated that knockdown HDAC9 could significantly induce cell cycle arrest at G1 phase in retinoblastoma cells. Western blot assay showed downregulation of HDAC9 could significantly decrease cyclin E2 and CDK2 expression. Lastly, xenograft study in nude mice showed that downregulation of HDAC9 inhibited tumor growth and development in vivo. Therefore, our results suggest that HDAC9 could serve as a novel potential therapeutic target in the treatment of retinoblastoma. - Highlights: • High expression of HDAC9 correlates with poor patient prognosis. • Downregulation of HDAC9 inhibits cell proliferation in retinoblastoma cells. • Downregulation of HDAC9 induces cell cycle arrest at G1 phase in retinoblastoma cells. • Downregulation of HDAC9 suppresses tumor growth in nude mice.

  17. Downregulation of HDAC9 inhibits cell proliferation and tumor formation by inducing cell cycle arrest in retinoblastoma

    International Nuclear Information System (INIS)

    Zhang, Yiting; Wu, Dan; Xia, Fengjie; Xian, Hongyu; Zhu, Xinyue; Cui, Hongjuan; Huang, Zhenping

    2016-01-01

    Histone deacetylase 9 (HDAC9) is a member of class II HDACs, which regulates a wide variety of normal and abnormal physiological functions. Recently, HDAC9 has been found to be overexpressed in some types of human cancers. However, the role of HDAC9 in retinoblastoma remains unclear. In this study, we found that HDAC9 was commonly expressed in retinoblastoma tissues and HDAC9 was overexpressed in prognostically poor retinoblastoma patients. Through knocking down HDAC9 in Y79 and WERI-Rb-1 cells, the expression level of HDAC9 was found to be positively related to cell proliferation in vitro. Further investigation indicated that knockdown HDAC9 could significantly induce cell cycle arrest at G1 phase in retinoblastoma cells. Western blot assay showed downregulation of HDAC9 could significantly decrease cyclin E2 and CDK2 expression. Lastly, xenograft study in nude mice showed that downregulation of HDAC9 inhibited tumor growth and development in vivo. Therefore, our results suggest that HDAC9 could serve as a novel potential therapeutic target in the treatment of retinoblastoma. - Highlights: • High expression of HDAC9 correlates with poor patient prognosis. • Downregulation of HDAC9 inhibits cell proliferation in retinoblastoma cells. • Downregulation of HDAC9 induces cell cycle arrest at G1 phase in retinoblastoma cells. • Downregulation of HDAC9 suppresses tumor growth in nude mice.

  18. Imaging Nuclear Morphology and Organization in Cleared Plant Tissues Treated with Cell Cycle Inhibitors.

    Science.gov (United States)

    de Souza Junior, José Dijair Antonino; de Sa, Maria Fatima Grossi; Engler, Gilbert; Engler, Janice de Almeida

    2016-01-01

    Synchronization of root cells through chemical treatment can generate a large number of cells blocked in specific cell cycle phases. In plants, this approach can be employed for cell suspension cultures and plant seedlings. To identify plant cells in the course of the cell cycle, especially during mitosis in meristematic tissues, chemical inhibitors can be used to block cell cycle progression. Herein, we present a simplified and easy-to-apply protocol to visualize mitotic figures, nuclei morphology, and organization in whole Arabidopsis root apexes. The procedure is based on tissue clearing, and fluorescent staining of nuclear DNA with DAPI. The protocol allows carrying out bulk analysis of nuclei and cell cycle phases in root cells and will be valuable to investigate mutants like overexpressing lines of genes disturbing the plant cell cycle.

  19. Testicular cell cytoskeleton in the newt, Triturus marmoratus marmoratus, during the annual cycle.

    Science.gov (United States)

    Ramos, P; De Miguel, M P; Arenas, M I; Fraile, B; Paniagua, R

    1996-04-15

    Light and electron microscopy immunohistochemical studies and Western blotting analysis of cytoskeletal proteins have been carried out in the testis of the marbled newt (Triturus marmoratus marmoratus) during the annual testicular cycle. The present findings revealed homologies and differences with regard to those reported in the testes of mammals and other vertebrates. Changes in immunohistochemical expression have also been detected in the course of the annual cycle. Actin and tubulin, which were scanty and diffusely located in spermatogonia and spermatocytes, increased their expression and reorganized during spermiogenesis. Vimentin and keratin, undetected in spermatogonia and spermatocytes, were expressed in differentiating spermatids and spermatozoa. In these cells, actin might be related with the connection of the axial fiber to the undulating membrane and the coordination of movement by both structures, while vimentin might be involved in the maintenance of the spatial relationship between the axoneme and the marginal fiber. During the first stages of spermatogenesis, the cytoplasm of Sertoli cells (follicular cells) showed a diffuse immunoreaction to actin, myosin, and tubulin and no vimentin immunolabeling. In advanced spermiogenesis, the follicular cells showed an intense immunoreaction to actin, myosin, tubulin, and vimentin in the apical projections that surrounded the spermatid heads. These apical cytoskeletal components might be involved in spermatid elongation, since the spermatids display no manchette, and in spermatozoon positioning and grouping. The colocalization of myosin and actin in the follicular cells suggests that actin filaments from contractile bundles and that contraction might be involved in changes in the Sertoli cell shape that accompany germ cell development during spermatogenesis. The interstitial cells immunostained to actin, myosin, tubulin, and vimentin. These cells, together with follicular cells, seemed to form the glandular

  20. The cell cycle regulators p15, p16, p18 and p19 : functions and regulation during normal cell cycle and in multistep carcinogenesis

    OpenAIRE

    Thullberg, Minna

    2000-01-01

    The tumor suppressor protein p16INK4a and its family members p15INK4b, p18INK4c and p19INK4d (the INK4 proteins) inhibit the cyclin-dependent kinases CDK4 and CDK6, which are key regulators of the retinoblastoma protein (pRb). pRb guards entry into the S phase of the mammalian cell division cycle (the cell cycle), a process evolved to ensure balanced cell proliferation. Deregulation of the cell cycle including the 'RB pathway' may have devastating consequences such as develo...

  1. Measuring cell cycle progression kinetics with metabolic labeling and flow cytometry.

    Science.gov (United States)

    Fleisig, Helen; Wong, Judy

    2012-05-22

    Precise control of the initiation and subsequent progression through the various phases of the cell cycle are of paramount importance in proliferating cells. Cell cycle division is an integral part of growth and reproduction and deregulation of key cell cycle components have been implicated in the precipitating events of carcinogenesis. Molecular agents in anti-cancer therapies frequently target biological pathways responsible for the regulation and coordination of cell cycle division. Although cell cycle kinetics tend to vary according to cell type, the distribution of cells amongst the four stages of the cell cycle is rather consistent within a particular cell line due to the consistent pattern of mitogen and growth factor expression. Genotoxic events and other cellular stressors can result in a temporary block of cell cycle progression, resulting in arrest or a temporary pause in a particular cell cycle phase to allow for instigation of the appropriate response mechanism. The ability to experimentally observe the behavior of a cell population with reference to their cell cycle progression stage is an important advance in cell biology. Common procedures such as mitotic shake off, differential centrifugation or flow cytometry-based sorting are used to isolate cells at specific stages of the cell cycle. These fractionated, cell cycle phase-enriched populations are then subjected to experimental treatments. Yield, purity and viability of the separated fractions can often be compromised using these physical separation methods. As well, the time lapse between separation of the cell populations and the start of experimental treatment, whereby the fractionated cells can progress from the selected cell cycle stage, can pose significant challenges in the successful implementation and interpretation of these experiments. Other approaches to study cell cycle stages include the use of chemicals to synchronize cells. Treatment of cells with chemical inhibitors of key

  2. Nuclear Localization of Diacylglycerol Kinase Alpha in K562 Cells Is Involved in Cell Cycle Progression.

    Science.gov (United States)

    Poli, Alessandro; Fiume, Roberta; Baldanzi, Gianluca; Capello, Daniela; Ratti, Stefano; Gesi, Marco; Manzoli, Lucia; Graziani, Andrea; Suh, Pann-Ghill; Cocco, Lucio; Follo, Matilde Y

    2017-09-01

    Phosphatidylinositol (PI) signaling is an essential regulator of cell motility and proliferation. A portion of PI metabolism and signaling takes place in the nuclear compartment of eukaryotic cells, where an array of kinases and phosphatases localize and modulate PI. Among these, Diacylglycerol Kinases (DGKs) are a class of phosphotransferases that phosphorylate diacylglycerol and induce the synthesis of phosphatidic acid. Nuclear DGKalpha modulates cell cycle progression, and its activity or expression can lead to changes in the phosphorylated status of the Retinoblastoma protein, thus, impairing G1/S transition and, subsequently, inducing cell cycle arrest, which is often uncoupled with apoptosis or autophagy induction. Here we report for the first time not only that the DGKalpha isoform is highly expressed in the nuclei of human erythroleukemia cell line K562, but also that its nuclear activity drives K562 cells through the G1/S transition during cell cycle progression. J. Cell. Physiol. 232: 2550-2557, 2017. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

  3. Andrographolide inhibits proliferation and induces cell cycle arrest and apoptosis in human melanoma cells.

    Science.gov (United States)

    Liu, Guo; Chu, Haihan

    2018-04-01

    Andrographolide (Andro), a natural compound isolated from Andrographis paniculata , has been demonstrated to have anticancer efficacy in several types of tumors. In the present study, the anticancer effects and mechanism of Andro in human malignant melanoma were investigated. Cell viability analysis was performed using an MTT assay and the effect of Andro on the cell cycle and apoptosis of human malignant melanoma cells was determined by flow cytometry. Western blot analysis was performed to evaluate the protein expression levels of human malignant melanoma cells following treatment with Andro. The results revealed that Andro potently inhibited cell proliferation by inducing G2/M cell-cycle arrest in human malignant melanoma C8161 and A375 cell lines. In addition, treatment with Andro induced apoptosis, which was associated with the cleavage of poly(adenosine diphosphate-ribose) polymerase and activation of caspase-3. It was observed that Andro induced activation of the c-Jun N-terminal kinase and p38 signaling pathway, which may be connected with cell cycle arrest and apoptosis. In conclusion, the results demonstrated that Andro may be a promising and effective agent for antitumor therapy against human malignant melanoma.

  4. Cell cycle phase of nondividing cells in aging human cell cultures determined by DNA content and chromosomal constitution

    International Nuclear Information System (INIS)

    Yanishevsky, R.M.

    1975-01-01

    Human diploid cell cultures, strain WI-38, have a finite proliferative capacity and have been proposed as a model of biological aging. To identify the cell cycle phase of the nondividing cells, cultures of various ages were exposed to 3 Hdt for 48 hours to label dividing cells, then the cycle phase was identified for individual cells by one of two methods, and finally, the proliferative status of the same cells was scored by autoradiographic evidence of 3 HdT uptake. The methods to identify the cycle phase were: determination of DNA strain content by Feulgen scanning cytophotometry, and determination of chromosome constitution by the technique of premature chromosome condensation (PCC). Preliminary experiments showed the effect of continuous exposure to various levels of 3 HdT on cell growth. High levels of 3 HdT inhibited cell cycle traverse: the cell number and labeling index curves reached a plateau; the cell volume increased; the cells accumulated with 4C DNA contents and it appeared that they blocked in G 2 phase. This pattern is consistent with a radiation effect. (U.S.)

  5. Timing of initiation of macronuclear DNA synthesis is set during the preceding cell cycle in Paramecium tetraurelia: analysis of the effects of abrupt changes in nutrient level

    Energy Technology Data Exchange (ETDEWEB)

    Ching, A.S.L.; Berger, J.D.

    1986-11-01

    In many eukaryotic organisms, initiation of DNA synthesis is associated with a major control point within the cell cycle and reflects the commitment of the cell to the DNA replication-division portion of the cell cycle. In paramecium, the timing of DNA synthesis initiation is established prior to fission during the preceding cell cycle. DNA synthesis normally starts at 0.25 in the cell cycle. When dividing cells are subjected to abrupt nutrient shift-up by transfer from a chemostat culture to medium with excess food, or shift-down from a well-fed culture to exhausted medium, DNA synthesis initiation in the post-shift cell cycle occurs at 0.25 of the parental cell cycle and not at either 0.25 in the post-shift cell cycle or at 0.25 in the equilibrium cell cycle produced under the post-shift conditions. The long delay prior to initiation of DNA synthesis following nutritional shift-up is not a consequence of continued slow growth because the rate of protein synthesis increases rapidly to the normal level after shift-up. Analysis of the relation between increase in cell mass and initiation of DNA synthesis following nutritional shifts indicates that increase in cell mass, per se, is neither a necessary nor a sufficient condition for initiation of DNA synthesis, in spite of the strong association between accumulation of cell mass and initiation of DNA synthesis in cells growing under steady-state conditions.

  6. Timing of initiation of macronuclear DNA synthesis is set during the preceding cell cycle in Paramecium tetraurelia: analysis of the effects of abrupt changes in nutrient level

    International Nuclear Information System (INIS)

    Ching, A.S.L.; Berger, J.D.

    1986-01-01

    In many eukaryotic organisms, initiation of DNA synthesis is associated with a major control point within the cell cycle and reflects the commitment of the cell to the DNA replication-division portion of the cell cycle. In paramecium, the timing of DNA synthesis initiation is established prior to fission during the preceding cell cycle. DNA synthesis normally starts at 0.25 in the cell cycle. When dividing cells are subjected to abrupt nutrient shift-up by transfer from a chemostat culture to medium with excess food, or shift-down from a well-fed culture to exhausted medium, DNA synthesis initiation in the post-shift cell cycle occurs at 0.25 of the parental cell cycle and not at either 0.25 in the post-shift cell cycle or at 0.25 in the equilibrium cell cycle produced under the post-shift conditions. The long delay prior to initiation of DNA synthesis following nutritional shift-up is not a consequence of continued slow growth because the rate of protein synthesis increases rapidly to the normal level after shift-up. Analysis of the relation between increase in cell mass and initiation of DNA synthesis following nutritional shifts indicates that increase in cell mass, per se, is neither a necessary nor a sufficient condition for initiation of DNA synthesis, in spite of the strong association between accumulation of cell mass and initiation of DNA synthesis in cells growing under steady-state conditions

  7. Abnormal mitosis triggers p53-dependent cell cycle arrest in human tetraploid cells.

    Science.gov (United States)

    Kuffer, Christian; Kuznetsova, Anastasia Yurievna; Storchová, Zuzana

    2013-08-01

    Erroneously arising tetraploid mammalian cells are chromosomally instable and may facilitate cell transformation. An increasing body of evidence shows that the propagation of mammalian tetraploid cells is limited by a p53-dependent arrest. The trigger of this arrest has not been identified so far. Here we show by live cell imaging of tetraploid cells generated by an induced cytokinesis failure that most tetraploids arrest and die in a p53-dependent manner after the first tetraploid mitosis. Furthermore, we found that the main trigger is a mitotic defect, in particular, chromosome missegregation during bipolar mitosis or spindle multipolarity. Both a transient multipolar spindle followed by efficient clustering in anaphase as well as a multipolar spindle followed by multipolar mitosis inhibited subsequent proliferation to a similar degree. We found that the tetraploid cells did not accumulate double-strand breaks that could cause the cell cycle arrest after tetraploid mitosis. In contrast, tetraploid cells showed increased levels of oxidative DNA damage coinciding with the p53 activation. To further elucidate the pathways involved in the proliferation control of tetraploid cells, we knocked down specific kinases that had been previously linked to the cell cycle arrest and p53 phosphorylation. Our results suggest that the checkpoint kinase ATM phosphorylates p53 in tetraploid cells after abnormal mitosis and thus contributes to proliferation control of human aberrantly arising tetraploids.

  8. Business cycles and the financial performance of fuel cell companies

    International Nuclear Information System (INIS)

    Henriques, I.; Sadorsky, P.

    2005-01-01

    Fuel cells are expected to play a major role in a hydrogen powered world. They will provide power to homes, modes of transportation and appliances. Hydrogen is the most abundant element in nature, but it must be extracted in order to be usable. It can be produced from oil, natural gas and coal or from renewable sources such as biomass, thermal or nuclear reactions. Fuel cells running on hydrogen extracted from non renewable resources have an efficiency of 30 per cent, which is twice as efficient as an internal combustion engine. The greatest barrier to mass commercialization is the cost of making hydrogen-powered auto engines. Also, an infrastructure must be developed to refill hydrogen cars. One solution is to build a hydrogen highway using the existing natural gas grid to produce hydrogen and sell it at existing filling stations. The cost of building 12,000 refueling pumps in urban areas which will provide access to 70 per cent of America's population is estimated at $10 to $15 billion. This paper described the vector autoregression (VAR) model which empirically examines the relationship between financial performance of fuel cell companies and business cycles. It was used to measure how sensitive the financial performance of fuel cell companies are to changes in macroeconomic activity. A four variable VAR model was developed to examine the relationship between stock prices, oil prices and interest rates. It was shown that the stock prices of fuel cell companies are affected by shocks to technology stock prices and oil prices, with the former having a longer lasting impact. These results add to the growing literature that oil price movements are not as important as once thought. 15 refs., 3 tabs., 3 figs

  9. Cyclebase.org: version 2.0, an updated comprehensive, multi-species repository of cell cycle experiments and derived analysis results

    DEFF Research Database (Denmark)

    Jensen, Lars Juhl; Wernersson, Rasmus; Brunak, Søren

    2010-01-01

    Cell division involves a complex series of events orchestrated by thousands of molecules. To study this process, researchers have employed mRNA expression profiling of synchronously growing cell cultures progressing through the cell cycle. These experiments, which have been carried out in several...... organisms, are not easy to access, combine and evaluate. Complicating factors include variation in interdivision time between experiments and differences in relative duration of each cell-cycle phase across organisms. To address these problems, we created Cyclebase, an online resource of cell-cycle......-related experiments. This database provides an easy-to-use web interface that facilitates visualization and download of genome-wide cell-cycle data and analysis results. Data from different experiments are normalized to a common timescale and are complimented with key cell-cycle information and derived analysis...

  10. An Examination of Sunspot Number Rates of Growth and Decay in Relation to the Sunspot Cycle

    Science.gov (United States)

    Wilson, Robert M.; Hathaway, David H.

    2006-01-01

    On the basis of annual sunspot number averages, sunspot number rates of growth and decay are examined relative to both minimum and maximum amplitudes and the time of their occurrences using cycles 12 through present, the most reliably determined sunspot cycles. Indeed, strong correlations are found for predicting the minimum and maximum amplitudes and the time of their occurrences years in advance. As applied to predicting sunspot minimum for cycle 24, the next cycle, its minimum appears likely to occur in 2006, especially if it is a robust cycle similar in nature to cycles 17-23.

  11. Optimization of immunolocalization of cell cycle proteins in human corneal endothelial cells

    Science.gov (United States)

    He, Zhiguo; Campolmi, Nelly; Ha Thi, Binh-Minh; Dumollard, Jean-Marc; Peoc’h, Michel; Garraud, Olivier; Piselli, Simone; Gain, Philippe

    2011-01-01

    Purpose En face observation of corneal endothelial cells (ECs) using flat-mounted whole corneas is theoretically much more informative than observation of cross-sections that show only a few cells. Nevertheless, it is not widespread for immunolocalization (IL) of proteins, probably because the endothelium, a superficial monolayer, behaves neither like a tissue in immunohistochemistry (IHC) nor like a cell culture in immunocytochemistry (ICC). In our study we optimized IL for ECs of flat-mounted human corneas to study the expression of cell cycle-related proteins. Methods We systematically screened 15 fixation and five antigen retrieval (AR) methods on 118 human fresh or stored corneas (organ culture at 31 °C), followed by conventional immunofluorescence labeling. First, in an attempt to define a universal protocol, we selected combinations able to correctly localize four proteins that are perfectly defined in ECs (zonula occludens-1 [ZO-1] and actin) or ubiquitous (heterogeneous nuclear ribonucleoprotein L [hnRNP L] and histone H3). Second, we screened protocols adapted to the revelation of 9 cell cycle proteins: Ki67, proliferating cell nuclear antigen (PCNA), minichromosome maintenance protein 2 (MCM2), cyclin D1, cyclin E, cyclin A, p16Ink4a, p21Cip1 and p27Kip1. Primary antibody controls (positive controls) were performed on both epithelial cells of the same, simultaneously-stained whole corneas, and by ICC on human ECs in in vitro non-confluent cultures. Both controls are known to contain proliferating cells. IL efficiency was evaluated by two observers in a masked fashion. Correct localization at optical microscopy level in ECs was define as clear labeling with no background, homogeneous staining, agreement with previous works on ECs and/or protein functions, as well as a meaningful IL in proliferating cells of both controls. Results The common fixation with 4% formaldehyde (gold standard for IHC) failed to reveal 12 of the 13 proteins. In contrast, they

  12. Iodine-131 treatment of thyroid cancer cells leads to suppression of cell proliferation followed by induction of cell apoptosis and cell cycle arrest by regulation of B-cell translocation gene 2-mediated JNK/NF-κB pathways

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, L.M.; Pang, A.X., E-mail: zhaoliming515@126.com [Department of Nuclear Medicine, Linyi People' s Hospital, Linyi (China); Department of Urology, Linyi People' s Hospital, Linyi (China)

    2017-10-01

    Iodine-131 ({sup 131}I) is widely used for the treatment of thyroid-related diseases. This study aimed to investigate the expression of p53 and BTG2 genes following {sup 131}I therapy in thyroid cancer cell line SW579 and the possible underlying mechanism. SW579 human thyroid squamous carcinoma cells were cultured and treated with {sup 131}I. They were then assessed for {sup 131}I uptake, cell viability, apoptosis, cell cycle arrest, p53 expression, and BTG2 gene expression. SW579 cells were transfected with BTG2 siRNA, p53 siRNA and siNC and were then examined for the same aforementioned parameters. When treated with a JNK inhibitor of SP600125 and {sup 131}I or with a NF-kB inhibitor of BMS-345541 and {sup 131}I, non-transfected SW579 cells were assessed in JNK/NFkB pathways. It was observed that {sup 131}I significantly inhibited cell proliferation, promoted cell apoptosis and cell cycle arrest. Both BTG2 and p53 expression were enhanced in a dose-dependent manner. An increase in cell viability by up-regulation in Bcl2 gene, a decrease in apoptosis by enhanced CDK2 gene expression and a decrease in cell cycle arrest at G{sub 0}/G{sub 1} phase were also observed in SW579 cell lines transfected with silenced BTG2 gene. When treated with SP600125 and {sup 131}I, the non transfected SW579 cell lines significantly inhibited JNK pathway, NF-kB pathway and the expression of BTG2. However, when treated with BMS-345541 and {sup 131}I, only the NF-kB pathway was suppressed. {sup 131}I suppressed cell proliferation, induced cell apoptosis, and promoted cell cycle arrest of thyroid cancer cells by up-regulating B-cell translocation gene 2-mediated activation of JNK/NF--κB pathways. (author)

  13. Hesperidin inhibits HeLa cell proliferation through apoptosis mediated by endoplasmic reticulum stress pathways and cell cycle arrest

    International Nuclear Information System (INIS)

    Wang, Yaoxian; Yu, Hui; Zhang, Jin; Gao, Jing; Ge, Xin; Lou, Ge

    2015-01-01

    Hesperidin (30, 5, 9-dihydroxy-40-methoxy-7-orutinosyl flavanone) is a flavanone that is found mainly in citrus fruits and has been shown to have some anti-neoplastic effects. The aim of the present study was to investigate the effect of hesperidin on apoptosis in human cervical cancer HeLa cells and to identify the mechanism involved. Cells were treated with hesperidin (0, 20, 40, 60, 80, and 100 μM) for 24, 48, or 72 h and relative cell viability was assessed using the 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide (MTT) assay. Hesperidin inhibited the proliferation of HeLa cells in a concentration- and time-dependent manner. Hesperidin-induced apoptosis in HeLa cells was characterized by increased nuclear condensation and DNA fragmentation. Furthermore, increased levels of GADD153/CHOP and GRP78 indicated hesperidin-induced apoptosis in HeLa cells involved a caspase-dependent pathway, presumably downstream of the endoplasmic reticulum stress pathway. Both of these proteins are hallmarks of endoplasmic reticulum stress. Hesperidin also promoted the formation of reactive oxygen species, mobilization of intracellular Ca 2+ , loss of mitochondrial membrane potential (ΔΨm), increased release of cytochrome c and apoptosis-inducing factor from mitochondria, and promoted capase-3 activation. It also arrested HeLa cells in the G0/G1 phase in the cell cycle by downregulating the expression of cyclinD1, cyclinE1, and cyclin-dependent kinase 2 at the protein level. The effect of hesperidin was also verified on the human colon cancer cell HT-29 cells. We concluded that hesperidin inhibited HeLa cell proliferation through apoptosis involving endoplasmic reticulum stress pathways and cell cycle arrest

  14. Quantitative proteomic analysis of cell cycle of the dinoflagellate Prorocentrum donghaiense (Dinophyceae.

    Directory of Open Access Journals (Sweden)

    Da-Zhi Wang

    Full Text Available Dinoflagellates are the major causative agents of harmful algal blooms in the coastal zone, which has resulted in adverse effects on the marine ecosystem and public health, and has become a global concern. Knowledge of cell cycle regulation in proliferating cells is essential for understanding bloom dynamics, and so this study compared the protein profiles of Prorocentrum donghaiense at different cell cycle phases and identified differentially expressed proteins using 2-D fluorescence difference gel electrophoresis combined with MALDI-TOF-TOF mass spectrometry. The results showed that the synchronized cells of P. donghaiense completed a cell cycle within 24 hours and cell division was phased with the diurnal cycle. Comparison of the protein profiles at four cell cycle phases (G1, S, early and late G2/M showed that 53 protein spots altered significantly in abundance. Among them, 41 were identified to be involved in a variety of biological processes, e.g. cell cycle and division, RNA metabolism, protein and amino acid metabolism, energy and carbon metabolism, oxidation-reduction processes, and ABC transport. The periodic expression of these proteins was critical to maintain the proper order and function of the cell cycle. This study, to our knowledge, for the first time revealed the major biological processes occurring at different cell cycle phases which provided new insights into the mechanisms regulating the cell cycle and growth of dinoflagellates.

  15. The changes of stage distribution of seminiferous epithelium cycle and its correlations with Leydig cell stereological parameters in aging men.

    Science.gov (United States)

    Huang, Rui; Zhu, Wei-Jie; Li, Jing; Gu, Yi-Qun

    2014-12-01

    To evaluate the changes of stage distribution of seminiferous epithelium cycle and its correlations with Leydig cell stereological parameters in aging men. Point counting method was used to analyze the stereological parameters of Leydig cells. The stage number of seminiferous epithelium cycle was calculated in the same testicular tissue samples which were used for Leydig cell stereological analysis. The aging group had shown more severe pathological changes as well as higher pathologic scores than the young group. Compared with the control group, the volume density (VV) and surface density (NA) of Leydig cells in the aging group were increased significantly. The stage number of seminiferous epithelium cycle in the aging group was decreased coincidently compared to the young group. Leydig cell Vv in the young group has a positive relationship with stages I, II, III, V and VI of seminiferous epithelium cycle, and Leydig cell NA and numerical density (NV) were positively related to stage IV. However, only the correlation between NV and stage II was found in the aging group. The stage number of seminiferous epithelium cycle was decreased in aging testes. Changes in the stage distribution in aging testes were related to the Leydig cell stereological parameters which presented as a sign of morphological changes. Copyright © 2014 Elsevier GmbH. All rights reserved.

  16. Episodic angioedema with eosinophilia (Gleich syndrome) is a multilineage cell cycling disorder.

    Science.gov (United States)

    Khoury, Paneez; Herold, Jacqueline; Alpaugh, Alexandra; Dinerman, Ellen; Holland-Thomas, Nicole; Stoddard, Jennifer; Gurprasad, Shakuntala; Maric, Irina; Simakova, Olga; Schwartz, Lawrence B; Fong, Juelia; Lee, Chyi-Chia Richard; Xi, Liqiang; Wang, Zengfeng; Raffeld, Mark; Klion, Amy D

    2015-03-01

    Episodic angioedema with eosinophilia (Gleich syndrome) is a rare disorder characterized by episodes of angioedema and eosinophilia that occur at monthly intervals and resolve spontaneously without therapy. Despite the striking periodicity of this disorder, its similarity to other cyclic hematopoietic disorders with multilineage involvement has not been assessed. To characterize the involvement of cell lineages in the etiology and pathogenesis of episodic angioedema with eosinophilia, four subjects were evaluated by blood counts and other analyses over the course of 1-2 months. Surface marker expression was assessed on T cells by flow cytometry and clonality by polymerase chain reaction. Intracellular cytokine evaluation, bone marrow and skin biopsies were performed during different parts of the cycle. Cycling of multiple cell lineages, including neutrophils, lymphocytes and eosinophils, was observed in the four subjects with the disorder with a periodicity of 25-35 days. An aberrant CD3(-)CD4(+) T-cell population was detected in all four subjects, and T-cell receptor rearrangement studies showed a clonal pattern in three subjects. A peak of type II cytokines was detected in the serum of subjects prior to the onset of symptoms and eosinophil cycling and corresponded to ex-vivo type II cytokines detected intracellularly in CD3(+)CD4(+)CD154(+) T cells. Although the etiology of episodic angioedema with eosinophilia is not yet known, multiple lineages, including lymphocytes, neutrophils and mast cells, are involved and may be related to disease pathogenesis. Whether these cells act directly or promote eosinophilia and eosinophil activation remains to be elucidated. All subjects gave informed consent and were evaluated under an Institutional Review Board-approved protocol (NCT00001406). Copyright© Ferrata Storti Foundation.

  17. Early mitotic degradation of the homeoprotein HOXC10 is potentially linked to cell cycle progression.

    Science.gov (United States)

    Gabellini, Davide; Colaluca, Ivan N; Vodermaier, Hartmut C; Biamonti, Giuseppe; Giacca, Mauro; Falaschi, Arturo; Riva, Silvano; Peverali, Fiorenzo A

    2003-07-15

    Hox proteins are transcription factors involved in controlling axial patterning, leukaemias and hereditary malformations. Here, we show that HOXC10 oscillates in abundance during the cell cycle, being targeted for degradation early in mitosis by the ubiquitin-dependent proteasome pathway. Among abdominal-B subfamily members, the mitotic proteolysis of HOXC10 appears unique, since the levels of the paralogous HOXD10 and the related homeoprotein HOXC13 are constant throughout the cell cycle. When two destruction box motifs (D-box) are mutated, HOXC10 is stabilized and cells accumulate in metaphase. HOXC10 appears to be a new prometaphase target of the anaphase-promoting complex (APC), since its degradation coincides with cyclin A destruction and is suppressed by expression of a dominant-negative form of UbcH10, an APC-associated ubiquitin-conjugating enzyme. Moreover, HOXC10 co-immunoprecipitates the APC subunit CDC27, and its in vitro degradation is reduced in APC-depleted extracts or by competition with the APC substrate cyclin A. These data imply that HOXC10 is a homeoprotein with the potential to influence mitotic progression, and might provide a link between developmental regulation and cell cycle control.

  18. Phylogenetic analysis of the Neks reveals early diversification of ciliary-cell cycle kinases.

    Directory of Open Access Journals (Sweden)

    Jeremy D K Parker

    2007-10-01

    Full Text Available NIMA-related kinases (Neks have been studied in diverse eukaryotes, including the fungus Aspergillus and the ciliate Tetrahymena. In the former, a single Nek plays an essential role in cell cycle regulation; in the latter, which has more than 30 Neks in its genome, multiple Neks regulate ciliary length. Mammalian genomes encode an intermediate number of Neks, several of which are reported to play roles in cell cycle regulation and/or localize to centrosomes. Previously, we reported that organisms with cilia typically have more Neks than organisms without cilia, but were unable to establish the evolutionary history of the gene family.We have performed a large-scale analysis of the Nek family using Bayesian techniques, including tests of alternate topologies. We find that the Nek family had already expanded in the last common ancestor of eukaryotes, a ciliated cell which likely expressed at least five Neks. We suggest that Neks played an important role in the common ancestor in regulating cilia, centrioles, and centrosomes with respect to mitotic entry, and that this role continues today in organisms with cilia. Organisms that lack cilia generally show a reduction in the number of Nek clades represented, sometimes associated with lineage specific expansion of a single clade, as has occurred in the plants.This is the first rigorous phylogenetic analysis of a kinase family across a broad array of phyla. Our findings provide a coherent framework for the study of Neks and their roles in coordinating cilia and cell cycle progression.

  19. Influence of cell cycle on responses of MCF-7 cells to benzo[a]pyrene

    Directory of Open Access Journals (Sweden)

    Giddings Ian

    2011-06-01

    Full Text Available Abstract Background Benzo[a]pyrene (BaP is a widespread environmental genotoxic carcinogen that damages DNA by forming adducts. This damage along with activation of the aryl hydrocarbon receptor (AHR induces complex transcriptional responses in cells. To investigate whether human cells are more susceptible to BaP in a particular phase of the cell cycle, synchronised breast carcinoma MCF-7 cells were exposed to BaP. Cell cycle progression was analysed by flow cytometry, DNA adduct formation was assessed by 32P-postlabeling analysis, microarrays of 44K human genome-wide oligos and RT-PCR were used to detect gene expression (mRNA changes and Western blotting was performed to determine the expression of some proteins, including cytochrome P450 (CYP 1A1 and CYP1B1, which are involved in BaP metabolism. Results Following BaP exposure, cells evaded G1 arrest and accumulated in S-phase. Higher levels of DNA damage occurred in S- and G2/M- compared with G0/G1-enriched cultures. Genes that were found to have altered expression included those involved in xenobiotic metabolism, apoptosis, cell cycle regulation and DNA repair. Gene ontology and pathway analysis showed the involvement of various signalling pathways in response to BaP exposure, such as the Catenin/Wnt pathway in G1, the ERK pathway in G1 and S, the Nrf2 pathway in S and G2/M and the Akt pathway in G2/M. An important finding was that higher levels of DNA damage in S- and G2/M-enriched cultures correlated with higher levels of CYP1A1 and CYP1B1 mRNA and proteins. Moreover, exposure of synchronised MCF-7 cells to BaP-7,8-diol-9,10-epoxide (BPDE, the ultimate carcinogenic metabolite of BaP, did not result in significant changes in DNA adduct levels at different phases of the cell cycle. Conclusions This study characterised the complex gene response to BaP in MCF-7 cells and revealed a strong correlation between the varying efficiency of BaP metabolism and DNA damage in different phases of the cell

  20. DNA Damage, Cell Cycle Arrest, and Apoptosis Induction Caused by Lead in Human Leukemia Cells

    Directory of Open Access Journals (Sweden)

    Clement G. Yedjou

    2015-12-01

    Full Text Available In recent years, the industrial use of lead has been significantly reduced from paints and ceramic products, caulking, and pipe solder. Despite this progress, lead exposure continues to be a significant public health concern. The main goal of this research was to determine the in vitro mechanisms of lead nitrate [Pb(NO32] to induce DNA damage, apoptosis, and cell cycle arrest in human leukemia (HL-60 cells. To reach our goal, HL-60 cells were treated with different concentrations of Pb(NO32 for 24 h. Live cells and necrotic death cells were measured by the propidium idiode (PI assay using the cellometer vision. Cell apoptosis was measured by the flow cytometry and DNA laddering. Cell cycle analysis was evaluated by the flow cytometry. The result of the PI demonstrated a significant (p < 0.05 increase of necrotic cell death in Pb(NO32-treated cells, indicative of membrane rupture by Pb(NO32 compared to the control. Data generated from the comet assay indicated a concentration-dependent increase in DNA damage, showing a significant increase (p < 0.05 in comet tail-length and percentages of DNA cleavage. Data generated from the flow cytometry assessment indicated that Pb(NO32 exposure significantly (p < 0.05 increased the proportion of caspase-3 positive cells (apoptotic cells compared to the control. The flow cytometry assessment also indicated Pb(NO32 exposure caused cell cycle arrest at the G0/G1 checkpoint. The result of DNA laddering assay showed presence of DNA smear in the agarose gel with little presence of DNA fragments in the treated cells compared to the control. In summary, Pb(NO32 inhibits HL-60 cells proliferation by not only inducing DNA damage and cell cycle arrest at the G0/G1 checkpoint but also triggering the apoptosis through caspase-3 activation and nucleosomal DNA fragmentation accompanied by secondary necrosis. We believe that our study provides a new insight into the mechanisms of Pb(NO32 exposure and its associated adverse

  1. New therapeutic directions for advanced pancreatic cancer: cell cycle inhibitors, stromal modifiers and conjugated therapies.

    Science.gov (United States)

    Matera, Robert; Saif, Muhammad Wasif

    2017-09-01

    Pancreatic adenocarcinoma is a devastating malignancy with an extremely poor prognosis. These tumors progress rapidly and somewhat silently with few specific symptoms and are relatively resistant to chemotherapeutic agents. Many agents, including cell cycle inhibitors, are under development for the treatment of this cancer for which there are disappointingly few treatment options. Areas covered: Here we outline the existing approved treatments for advanced pancreatic disease and discuss a range of novel therapies currently under development including cell cycle inhibitors, stromal modifiers and conjugated therapies. We also describe the current state of the pancreatic cancer therapeutics market both past and future. Expert opinion: Despite the recent explosion of novel therapies with an array of unique targets, the core treatment of pancreatic cancer still with traditional cytotoxic agents with a few exceptions. However, as these novel treatments move through the pipeline, we are hopeful that there will soon be a number of effective options for patients with advanced pancreatic cancer.

  2. Cell cycle perturbations induced by Cisplatin in normal and tumor transformed cells

    Czech Academy of Sciences Publication Activity Database

    Mareš, Vladislav; Mazzini, G.; Lisá, Věra; Ferrari, C.; Malík, Radek; Šedo, A.

    2001-01-01

    Roč. 5, - (2001), s. 23-29 ISSN 1212-3137 Grant - others:GA UK(XC) 58/1999/C; LF UK(XC) 206019-2-"Oncology" Institutional research plan: CEZ:AV0Z5011922 Keywords : cell cycle * cisplatin * DNA content Subject RIV: FD - Oncology ; Hematology

  3. Polycyclic aromatic hydrocarbons disrupt cell cycle control in contact-inhibited rat liver oval cells

    Czech Academy of Sciences Publication Activity Database

    Kranz, A.; Andrysík, Zdeněk; Vondráček, Jan; Machala, M.; Faust, D.; Oesch, F.; Dietrich, C.

    2005-01-01

    Roč. 371, Suppl. 1 (2005), R117 ISSN 0028-1298. [Spring Meeting /46./ - Deutsche Gessellshaft fűr Experimentelle und Klinische Pharmakologie und Toxikologie. 15.03.2005-14.03.2005, Mainz] Institutional research plan: CEZ:AV0Z50040507 Keywords : AhR * cell cycle * PAU Subject RIV: BO - Biophysics

  4. Polyamine metabolism during the cell cycle of synchronized tobacco BY-2 cell line

    Czech Academy of Sciences Publication Activity Database

    Gemperlová, Lenka; Cvikrová, Milena; Fischerová, Lucie; Binarová, Pavla; Fischer, L.; Eder, Josef

    2009-01-01

    Roč. 47, č. 7 (2009), s. 584-591 ISSN 0981-9428 R&D Projects: GA AV ČR IAA500200719 Institutional research plan: CEZ:AV0Z50380511; CEZ:AV0Z50200510 Keywords : ADC * Cell cycle * DAO Subject RIV: EF - Botanics Impact factor: 2.485, year: 2009

  5. Function of trehalose and glycogen in cell cycle progression and cell viability in Saccharomyces cerevisiae

    NARCIS (Netherlands)

    Silljé, H H; Paalman, J W; ter Schure, E G; Olsthoorn, S Q; Verkleij, A J; Boonstra, Johannes; Verrips, C T

    Trehalose and glycogen accumulate in Saccharomyces cerevisiae when growth conditions deteriorate. It has been suggested that aside from functioning as storage factors and stress protectants, these carbohydrates may be required for cell cycle progression at low growth rates under carbon limitation.

  6. Mutant p53 transfection of astrocytic cells results in altered cell cycle control, radiation sensitivity, and tumorigenicity

    International Nuclear Information System (INIS)

    Kanady, Kirk E.; Mei Su; Proulx, Gary; Malkin, David M.; Pardo, Francisco S.

    1995-01-01

    Introduction: Alterations in the p53 tumor suppressor gene are one of the most frequent genetic alterations in malignant gliomas. An understanding of the molecular genetic events leading to glial tumor progression would aid in designing therapeutic vectors for controlling these challenging tumor types. We investigated whether mutations in coding exons of the p53 gene result in functional changes altering cell cycle 'checkpoint' control and the intrinsic radiation sensitivity of glial cells. Methods: An astrocytic cell line was derived from a low grade astrocytoma and characterized to be of human karyotype and GFAP positivity. Additionally, the cellular population has never formed tumors in immune-deficient mice. At early passage ( 2 as parameters. Cell kinetic analyses after 2, 5, and 10 Gy of ionizing radiation were conducted using propidium iodide FACS analyses. Results: Overall levels of p53 expression were increased 5-10 fold in the transfected cellular populations. Astrocytic cellular populations transfected with mutant p53 revealed a statistically significant increase in levels of resistance to ionizing radiation in vitro (2-tailed test, SF2, MID). Astrocytic cellular populations transfected with mutant p53, unlike the parental cells, were tumorigenic in SCID mice. Cell kinetic analyses indicated that the untransfected cell line demonstrated dose dependent G1 and G2 arrests. Following transfection, however, the resultant cellular population demonstrated a predominant G2 arrest. Conclusions: Astrocytic cellular populations derived from low grade astrocytomas, are relatively radiation sensitive, non-tumorigenic, and have intact cell cycle ''checkpoints.'' Cellular populations resulting upon transfection of parental cells with a dominant negative p53 mutation, are relatively radiation resistant, when compared to both parental and mock-transfected cells. Transfected cells demonstrate abnormalities of cell cycle control at the G1/S checkpoint, increases in levels

  7. Backup pathways of NHEJ in cells of higher eukaryotes: Cell cycle dependence

    International Nuclear Information System (INIS)

    Iliakis, George

    2009-01-01

    DNA double-strand breaks (DSBs) induced by ionizing radiation (IR) in cells of higher eukaryotes are predominantly repaired by a pathway of non-homologous end joining (NHEJ) utilizing Ku, DNA-PKcs, DNA ligase IV, XRCC4 and XLF/Cernunnos (D-NHEJ) as central components. Work carried out in our laboratory and elsewhere shows that when this pathway is chemically or genetically compromised, cells do not shunt DSBs to homologous recombination repair (HRR) but instead use another form of NHEJ operating as a backup (B-NHEJ). Here I review our efforts to characterize this repair pathway and discuss its dependence on the cell cycle as well as on the growth conditions. I present evidence that B-NHEJ utilizes ligase III, PARP-1 and histone H1. When B-NHEJ is examined throughout the cell cycle, significantly higher activity is observed in G2 phase that cannot be attributed to HRR. Furthermore, the activity of B-NHEJ is compromised when cells enter the plateau phase of growth. Together, these observations uncover a repair pathway with unexpected biochemical constitution and interesting cell cycle and growth factor regulation. They generate a framework for investigating the mechanistic basis of HRR contribution to DSB repair.

  8. Manipulation of Cell Cycle and Chromatin Configuration by Means of Cell-Penetrating Geminin.

    Directory of Open Access Journals (Sweden)

    Yoshinori Ohno

    Full Text Available Geminin regulates chromatin remodeling and DNA replication licensing which play an important role in regulating cellular proliferation and differentiation. Transcription of the Geminin gene is regulated via an E2F-responsive region, while the protein is being closely regulated by the ubiquitin-proteasome system. Our objective was to directly transduce Geminin protein into cells. Recombinant cell-penetrating Geminin (CP-Geminin was generated by fusing Geminin with a membrane translocating motif from FGF4 and was efficiently incorporated into NIH 3T3 cells and mouse embryonic fibroblasts. The withdrawal study indicated that incorporated CP-Geminin was quickly reduced after removal from medium. We confirmed CP-Geminin was imported into the nucleus after incorporation and also that the incorporated CP-Geminin directly interacted with Cdt1 or Brahma/Brg1 as the same manner as Geminin. We further demonstrated that incorporated CP-Geminin suppressed S-phase progression of the cell cycle and reduced nuclease accessibility in the chromatin, probably through suppression of chromatin remodeling, indicating that CP-Geminin constitutes a novel tool for controlling chromatin configuration and the cell cycle. Since Geminin has been shown to be involved in regulation of stem cells and cancer cells, CP-Geminin is expected to be useful for elucidating the role of Geminin in stem cells and cancer cells, and for manipulating their activity.

  9. The global regulatory architecture of transcription during the Caulobacter cell cycle.

    Directory of Open Access Journals (Sweden)

    Bo Zhou

    2015-01-01

    Full Text Available Each Caulobacter cell cycle involves differentiation and an asymmetric cell division driven by a cyclical regulatory circuit comprised of four transcription factors (TFs and a DNA methyltransferase. Using a modified global 5' RACE protocol, we globally mapped transcription start sites (TSSs at base-pair resolution, measured their transcription levels at multiple times in the cell cycle, and identified their transcription factor binding sites. Out of 2726 TSSs, 586 were shown to be cell cycle-regulated and we identified 529 binding sites for the cell cycle master regulators. Twenty-three percent of the cell cycle-regulated promoters were found to be under the combinatorial control of two or more of the global regulators. Previously unknown features of the core cell cycle circuit were identified, including 107 antisense TSSs which exhibit cell cycle-control, and 241 genes with multiple TSSs whose transcription levels often exhibited different cell cycle timing. Cumulatively, this study uncovered novel new layers of transcriptional regulation mediating the bacterial cell cycle.

  10. CREPT and p15RS regulate cell proliferation and cycling in chicken DF-1 cells through the Wnt/β-catenin pathway.

    Science.gov (United States)

    Jin, Kai; Chen, Hao; Zuo, Qisheng; Huang, Chuanli; Zhao, Ruifeng; Yu, Xinjian; Wang, Yinjie; Zhang, Yani; Chang, Zhijie; Li, Bichu

    2018-01-01

    The CREPT (cell cycle-related and expression elevated protein in tumor, also known as RPRD1B) and p15RS (p15 INK4b -related sequence, also known as RPRD1A) have been shown to regulate cell proliferation and alter the cell cycle through Wnt/β-catenin pathway downstream genes in human. Although several studies have revealed the mechanism by which CREPT and p15RS regulate cell proliferation in human and mammals, it is still unclear how these genes function in poultry. In order to determine the function of CREPT and p15RS in chicken, we examined the expression of CREPT and p15RS in a variety of chicken tissues and DF-1 cells. Then, we determined the effect of overexpression or depletion of CREPT or p15RS, by transiently transfecting chicken DF-1 cells with overexpression and short hairpin RNA (shRNA) vectors respectively, on the regulation of cell proliferation. The results showed that CREPT and p15RS had different expression patterns and opposite effects on the cell cycling and proliferation. Knockdown of p15RS expression or overexpression of CREPT facilitated cell proliferation by promoting the cell-cycle transition from G0/G1 to S-phase and G2/M, whereas knockdown of CREPT or overexpression of p15RS inhibited cell proliferation. Mechanistically, CREPT and p15RS control DF-1 cell proliferation by regulating the expression of Wnt/β-catenin pathway downstream regulatory genes, including β-catenin, TCF4, and Cyclin D1. In conclusion, CREPT and p15RS regulate cell proliferation and the cell-cycle transition in chicken DF-1 cells by regulating the transcription of Wnt/β-catenin pathway downstream regulatory genes. © 2017 Wiley Periodicals, Inc.

  11. Cell Division, a new open access online forum for and from the cell cycle community

    OpenAIRE

    Kaldis Philipp; Pagano Michele

    2006-01-01

    Abstract Cell Division is a new, open access, peer-reviewed online journal that publishes cutting-edge articles, commentaries and reviews on all exciting aspects of cell cycle control in eukaryotes. A major goal of this new journal is to publish timely and significant studies on the aberrations of the cell cycle network that occur in cancer and other diseases.

  12. The influence of arsenic trioxide on the cell cycle, apoptosis and expression of cyclin D1 in the Jurkat cell line.

    Science.gov (United States)

    Zuryń, Agnieszka; Litwiniec, Anna; Gagat, Maciej; Drzewucka, Joanna; Gackowska, Lidia; Grzanka, Alina

    2014-10-01

    Cyclin D1 drives cell cycle progression at the G1/S transition and is believed to play a significant role in tumorigenesis, contributing to efficient proliferation of many cancer cells. Consequently, it is also recognized as an end-point biomarker of therapeutic outcome for different treatment modalities in cancer. In this study we aimed to evaluate the expression and localization of cyclin D1 in arsenic trioxide (ATO) treated Jurkat cells (lymphoblastic leukemia cell line) and to correlate these results with the extent of cell death and/or cell cycle alterations. Jurkat cells were incubated with increasing concentrations of ATO (0.2, 0.6 and 1.0μM) for 24h in standard cell culture conditions. To reach our goal we performed annexin V/PI labeling for detection of cell death and RNase/PI labeling for evaluation of cell cycle distribution, which were followed by the respective flow cytometric analyses of ATO-treated Jurkat cells. Transmission electron microscopy was applied for visualization of the cell ultrastructure. For cyclin D1 estimation a biparametric cyclinD1/cell cycle assay was done and localization of the protein was shown after immuno-labeling using light microscopy (ABC procedure) and confocal fluorescence microscopy. We found that there were no significant changes in the percentages of cyclin D1-positive cells after the treatment with ATO, but at the same time mean fluorescence intensity reflecting cyclin D1 content was gradually increasing along with the cell cycle progression, irrespective of the applied dose of the drug. On the other hand, we found a nuclear-cytoplasmic shift of this protein as a major treatment-related response, which was in good accord with an increased rate of cell death and suggested that cyclin D1 cytoplasmic degradation is an important determinant of the therapeutic efficiency of ATO in the Jurkat cell line. Copyright © 2014 Elsevier GmbH. All rights reserved.

  13. Slow-cycling stem cells in hydra contribute to head regeneration

    Science.gov (United States)

    Govindasamy, Niraimathi; Murthy, Supriya; Ghanekar, Yashoda

    2014-01-01

    ABSTRACT Adult stem cells face the challenge of maintaining tissue homeostasis by self-renewal while maintaining their proliferation potential over the lifetime of an organism. Continuous proliferation can cause genotoxic/metabolic stress that can compromise the genomic integrity of stem cells. To prevent stem cell exhaustion, highly proliferative adult tissues maintain a pool of quiescent stem cells that divide only in response to injury and thus remain protected from genotoxic stress. Hydra is a remarkable organism with highly proliferative stem cells and ability to regenerate at whole animal level. Intriguingly, hydra does not display consequences of high proliferation, such as senescence or tumour formation. In this study, we investigate if hydra harbours a pool of slow-cycling stem cells that could help prevent undesirable consequences of continuous proliferation. Hydra were pulsed with the thymidine analogue 5-ethynyl-2′-deoxyuridine (EdU) and then chased in the absence of EdU to monitor the presence of EdU-retaining cells. A significant number of undifferentiated cells of all three lineages in hydra retained EdU for about 8–10 cell cycles, indicating that these cells did not enter cell cycle. These label-retaining cells were resistant to hydroxyurea treatment and were predominantly in the G2 phase of cell cycle. Most significantly, similar to mammalian quiescent stem cells, these cells rapidly entered cell division during head regeneration. This study shows for the first time that, contrary to current beliefs, cells in hydra display heterogeneity in their cell cycle potential and the slow-cycling cells in this population enter cell cycle during head regeneration. These results suggest an early evolution of slow-cycling stem cells in multicellular animals. PMID:25432513

  14. Slow-cycling stem cells in hydra contribute to head regeneration

    Directory of Open Access Journals (Sweden)

    Niraimathi Govindasamy

    2014-11-01

    Full Text Available Adult stem cells face the challenge of maintaining tissue homeostasis by self-renewal while maintaining their proliferation potential over the lifetime of an organism. Continuous proliferation can cause genotoxic/metabolic stress that can compromise the genomic integrity of stem cells. To prevent stem cell exhaustion, highly proliferative adult tissues maintain a pool of quiescent stem cells that divide only in response to injury and thus remain protected from genotoxic stress. Hydra is a remarkable organism with highly proliferative stem cells and ability to regenerate at whole animal level. Intriguingly, hydra does not display consequences of high proliferation, such as senescence or tumour formation. In this study, we investigate if hydra harbours a pool of slow-cycling stem cells that could help prevent undesirable consequences of continuous proliferation. Hydra were pulsed with the thymidine analogue 5-ethynyl-2′-deoxyuridine (EdU and then chased in the absence of EdU to monitor the presence of EdU-retaining cells. A significant number of undifferentiated cells of all three lineages in hydra retained EdU for about 8–10 cell cycles, indicating that these cells did not enter cell cycle. These label-retaining cells were resistant to hydroxyurea treatment and were predominantly in the G2 phase of cell cycle. Most significantly, similar to mammalian quiescent stem cells, these cells rapidly entered cell division during head regeneration. This study shows for the first time that, contrary to current beliefs, cells in hydra display heterogeneity in their cell cycle potential and the slow-cycling cells in this population enter cell cycle during head regeneration. These results suggest an early evolution of slow-cycling stem cells in multicellular animals.

  15. Cell cycle stage dependent variations in drug-induced topoisomerase II mediated DNA cleavage and cytotoxicity

    International Nuclear Information System (INIS)

    Estey, E.; Adlakha, R.C.; Hittelman, W.N.; Zwelling, L.A.

    1987-01-01

    The DNA cleavage produced by 4'-(9-acridinylamino)methanesulfon-m-anisidide (m-AMSA) in mammalian cells is putatively mediated by topoisomerase II. The authors found that in synchronized HeLa cells the frequency of such cleavage was 4-15-fold greater in mitosis than in S while the DNA of G 1 and G 2 cells exhibited an intermediate susceptibility to cleavage. The hypersensitivity of mitotic DNA to m-AMSA-induced cleavage was acquired relatively abruptly in late G 2 and was lost similarly abruptly in early G 1 . The susceptibility of mitotic cells to m-AMSA-induced DNA cleavage was not clearly paralleled by an increase in topoisomerase II activity in 350 mM NaCl extracts from mitotic cells compared to similar extracts from cells in G 1 , S, or G 2 . Furthermore, equal amounts of decatenating activity from cells in mitosis and S produced equal amounts of m-AMSA-induced cleavage of simian virus 40 (SV40) DNA; i.e., the interaction between m-AMSA and extractable enzyme was similar in mitosis and S. The DNA of mitotic cells was also hypersensitive to cleavage by 4'-demethylepipodophyllotoxin 4-(4,6-O-ethylidene-β-D-glucopyranoside) (etoposide), a drug that produces topoisomerase II mediated DNA cleavage without binding to DNA. Cell cycle stage dependent fluctuations in m-AMSA-induced DNA cleavage may result from fluctuations in the structure of chromatin per se that occur during the cell cycle. Surprisingly, cell cycle stage dependent differences in m-AMSA-induced DNA cleavage did not correlate with differences in the susceptibility to the cytotoxic effects of the drug. In fact, cells in S were most sensitive to these effects. These results are an exception to the previously observed parallel between the susceptibility of mammalian cells to drug-induced DNA cleavage and the susceptibility of the cells to drug-induced cytotoxicity and indicate the complexity of any relationship between the two phenomena

  16. ALG-2 knockdown in HeLa cells results in G2/M cell cycle phase accumulation and cell death

    DEFF Research Database (Denmark)

    Høj, Berit Rahbek; la Cour, Peter Jonas Marstrand; Mollerup, Jens

    2009-01-01

    downregulation induces accumulation of HeLa cells in the G2/M cell cycle phase and increases the amount of early apoptotic and dead cells. Caspase inhibition by the pan-caspase inhibitor zVAD-fmk attenuated the increase in the amount of dead cells following ALG-2 downregulation. Thus, our results indicate...... that ALG-2 has an anti-apoptotic function in HeLa cells by facilitating the passage through checkpoints in the G2/M cell cycle phase.......ALG-2 (apoptosis-linked gene-2 encoded protein) has been shown to be upregulated in a variety of human tumors questioning its previously assumed pro-apoptotic function. The aim of the present study was to obtain insights into the role of ALG-2 in human cancer cells. We show that ALG-2...

  17. Serum starvation and thymidine double blocking achieved efficient cell cycle synchronization and altered the expression of p27, p53, bcl-2 in canine breast cancer cells.

    Science.gov (United States)

    Tong, Jinjin; Sun, Dongdong; Yang, Chao; Wang, Yingxue; Sun, Sichao; Li, Qing; Bao, Jun; Liu, Yun

    2016-04-01

    Cell synchronization is an approach to obtain cell populations of the same stage, which is a prerequisite to studying the regulation of cell cycle progression in vivo. Serum starvation and thymidine double blocking (TdR) are two important practices in studying cell cycle synchronization. However, their effects on canine cancer cells as well as the regulatory mechanisms by these two methods are poorly understood. In this study, we determined the optimum conditions of serum starvation and TdR and their effects on cell cycle synchronization. We further explored the involvement of PI3K/Akt signaling pathway in the cell cycle synchronization by investigating the expression of three key genes (p27, p53 and bcl-2). Serum starvation resulted in a reversible cell cycle arrest and synchronously progress through G0/G1. The highest percentage of CHMm cells (87.47%) in G0/G1 stage was obtained after 42 h incubation with 0.5% fetal bovine serum (FBS). TdR double blocking could arrest 98.9% of CHMm cells in G1/S phase (0 h of release), and could arrest 93.74% of CHMm cells in S phase after 4h of release. We also found that the p27, p53, bcl-2 genes were most highly expressed in G0/G1 phase. Our current work revealed that serum starvation and TdR methods could achieve sufficient synchronization of CHMm cells. Moreover, the expression of p27, p53 and bcl-2 genes was related to cyclical movements and apoptosis. Our results will provide a new insight into cell cycle regulation and reprogramming of canine cancer cells induced by serum starvation and TdR blocking. Copyright © 2016 Elsevier Ltd. All rights reserved.

  18. Methyl jasmonate: putative mechanisms of action on cancer cells cycle, metabolism, and apoptosis.

    Science.gov (United States)

    Cesari, Italo Mario; Carvalho, Erika; Figueiredo Rodrigues, Mariana; Mendonça, Bruna Dos Santos; Amôedo, Nivea Dias; Rumjanek, Franklin David

    2014-01-01

    Methyl jasmonate (MJ), an oxylipid that induces defense-related mechanisms in plants, has been shown to be active against cancer cells both in vitro and in vivo, without affecting normal cells. Here we review most of the described MJ activities in an attempt to get an integrated view and better understanding of its multifaceted modes of action. MJ (1) arrests cell cycle, inhibiting cell growth and proliferation, (2) causes cell death through the intrinsic/extrinsic proapoptotic, p53-independent apoptotic, and nonapoptotic (necrosis) pathways, (3) detaches hexokinase from the voltage-dependent anion channel, dissociating glycolytic and mitochondrial functions, decreasing the mitochondrial membrane potential, favoring cytochrome c release and ATP depletion, activating pro-apoptotic, and inactivating antiapoptotic proteins, (4) induces reactive oxygen species mediated responses, (5) stimulates MAPK-stress signaling and redifferentiation in leukemia cells, (6) inhibits overexpressed proinflammatory enzymes in cancer cells such as aldo-keto reductase 1 and 5-lipoxygenase, and (7) inhibits cell migration and shows antiangiogenic and antimetastatic activities. Finally, MJ may act as a chemosensitizer to some chemotherapics helping to overcome drug resistant. The complete lack of toxicity to normal cells and the rapidity by which MJ causes damage to cancer cells turn MJ into a promising anticancer agent that can be used alone or in combination with other agents.

  19. Methyl Jasmonate: Putative Mechanisms of Action on Cancer Cells Cycle, Metabolism, and Apoptosis

    Directory of Open Access Journals (Sweden)

    Italo Mario Cesari

    2014-01-01

    Full Text Available Methyl jasmonate (MJ, an oxylipid that induces defense-related mechanisms in plants, has been shown to be active against cancer cells both in vitro and in vivo, without affecting normal cells. Here we review most of the described MJ activities in an attempt to get an integrated view and better understanding of its multifaceted modes of action. MJ (1 arrests cell cycle, inhibiting cell growth and proliferation, (2 causes cell death through the intrinsic/extrinsic proapoptotic, p53-independent apoptotic, and nonapoptotic (necrosis pathways, (3 detaches hexokinase from the voltage-dependent anion channel, dissociating glycolytic and mitochondrial functions, decreasing the mitochondrial membrane potential, favoring cytochrome c release and ATP depletion, activating pro-apoptotic, and inactivating antiapoptotic proteins, (4 induces reactive oxygen species mediated responses, (5 stimulates MAPK-stress signaling and redifferentiation in leukemia cells, (6 inhibits overexpressed proinflammatory enzymes in cancer cells such as aldo-keto reductase 1 and 5-lipoxygenase, and (7 inhibits cell migration and shows antiangiogenic and antimetastatic activities. Finally, MJ may act as a chemosensitizer to some chemotherapics helping to overcome drug resistant. The complete lack of toxicity to normal cells and the rapidity by which MJ causes damage to cancer cells turn MJ into a promising anticancer agent that can be used alone or in combination with other agents.

  20. Identification of transcription factors linked to cell cycle regulation in Arabidopsis

    OpenAIRE

    Dehghan Nayeri, Fatemeh

    2014-01-01

    Cell cycle is an essential process in growth and development of living organisms consists of the replication and mitotic phases separated by 2 gap phases; G1 and G2. It is tightly controlled at the molecular level and especially at the level of transcription. Precise regulation of the cell cycle is of central significance for plant growth and development and transcription factors are global regulators of gene expression playing essential roles in cell cycle regulation. This study has uncovere...

  1. Feedback loops and reciprocal regulation: recurring motifs in the systems biology of the cell cycle

    OpenAIRE

    Ferrell, James E.

    2013-01-01

    The study of eukaryotic cell cycle regulation over the last several decades has led to a remarkably detailed understanding of the complex regulatory system that drives this fundamental process. This allows us to now look for recurring motifs in the regulatory system. Among these are negative feedback loops, which underpin checkpoints and generate cell cycle oscillations; positive feedback loops, which promote oscillations and make cell cycle transitions switch-like and unidirectional; and rec...

  2. Single-cell paired-end genome sequencing reveals structural variation per cell cycle

    Science.gov (United States)

    Voet, Thierry; Kumar, Parveen; Van Loo, Peter; Cooke, Susanna L.; Marshall, John; Lin, Meng-Lay; Zamani Esteki, Masoud; Van der Aa, Niels; Mateiu, Ligia; McBride, David J.; Bignell, Graham R.; McLaren, Stuart; Teague, Jon; Butler, Adam; Raine, Keiran; Stebbings, Lucy A.; Quail, Michael A.; D’Hooghe, Thomas; Moreau, Yves; Futreal, P. Andrew; Stratton, Michael R.; Vermeesch, Joris R.; Campbell, Peter J.

    2013-01-01

    The nature and pace of genome mutation is largely unknown. Because standard methods sequence DNA from populations of cells, the genetic composition of individual cells is lost, de novo mutations in cells are concealed within the bulk signal and per cell cycle mutation rates and mechanisms remain elusive. Although single-cell genome analyses could resolve these problems, such analyses are error-prone because of whole-genome amplification (WGA) artefacts and are limited in the types of DNA mutation that can be discerned. We developed methods for paired-end sequence analysis of single-cell WGA products that enable (i) detecting multiple classes of DNA mutation, (ii) distinguishing DNA copy number changes from allelic WGA-amplification artefacts by the discovery of matching aberrantly mapping read pairs among the surfeit of paired-end WGA and mapping artefacts and (iii) delineating the break points and architecture of structural variants. By applying the methods, we capture DNA copy number changes acquired over one cell cycle in breast cancer cells and in blastomeres derived from a human zygote after in vitro fertilization. Furthermore, we were able to discover and fine-map a heritable inter-chromosomal rearrangement t(1;16)(p36;p12) by sequencing a single blastomere. The methods will expedite applications in basic genome research and provide a stepping stone to novel approaches for clinical genetic diagnosis. PMID:23630320

  3. Redox Changes During the Cell Cycle in the Embryonic Root Meristem of Arabidopsis thaliana.

    Science.gov (United States)

    de Simone, Ambra; Hubbard, Rachel; de la Torre, Natanael Viñegra; Velappan, Yazhini; Wilson, Michael; Considine, Michael J; Soppe, Wim J J; Foyer, Christine H

    2017-12-20

    The aim of this study was to characterize redox changes in the nuclei and cytosol occurring during the mitotic cell cycle in the embryonic roots of germinating Arabidopsis seedlings, and to determine how redox cycling was modified in mutants with a decreased capacity for ascorbate synthesis. Using an in vivo reduction-oxidation (redox) reporter (roGFP2), we show that transient oxidation of the cytosol and the nuclei occurred at G1 in the synchronized dividing cells of the Arabidopsis root apical meristem, with reduction at G2 and mitosis. This redox cycle was absent from low ascorbate mutants in which nuclei were significantly more oxidized than controls. The cell cycle-dependent increase in nuclear size was impaired in the ascorbate-deficient mutants, which had fewer cells per unit area in the root proliferation zone. The transcript profile of the dry seeds and size of the imbibed seeds was strongly influenced by low ascorbate but germination, dormancy release and seed aging characteristics were unaffected. These data demonstrate the presence of a redox cycle within the plant cell cycle and that the redox state of the nuclei is an important factor in cell cycle progression. Controlled oxidation is a key feature of the early stages of the plant cell cycle. However, sustained mild oxidation restricts nuclear functions and impairs progression through the cell cycle leading to fewer cells in the root apical meristem. Antioxid. Redox Signal. 27, 1505-1519.

  4. LIMD1 antagonizes E2F1 activity and cell cycle progression by enhancing Rb function in cancer cells.

    Science.gov (United States)

    Mayank, Adarsh K; Sharma, Shipra; Deshwal, Ravi K; Lal, Sunil K

    2014-07-01

    Tumour suppressor genes restrain inappropriate cell growth and division, as well as stimulate cell death to maintain tissue homeostasis. Loss of function leads to abnormal cellular behaviour, including hyperproliferation of cell and perturbation of cell cycle regulation. LIMD1 is a tumour suppressor gene located at chromosome 3p21.3, a region commonly deleted in many solid malignancies. LIMD1 interacts with retinoblastoma (Rb) and is involved in Rb-mediated downregulation of E2F1-target genes. However, the role of LIMD1 in cell cycle regulation remains unclear. We propose that LIMD1 induces cell cycle arrest, utilising Rb-E2F1 axis, and show that ectopic expression of LIMD1 in A549 cells results in hypo-phosphorylation that potentiates Rb function, which correlates with downregulation of E2F1. In agreement with these observations, LIMD1 overexpression retards cell cycle progression and blocks S-phase entry, as cells accumulate in G0/G1 phase and have reduced incorporation of BrdU. Most significantly, LIMD1-dependent effects on Rb function and cell cycle are reversed on depletion of endogenous LIMD1, underscoring its centrality in Rb-mediated cell cycle regulation. Hence, our findings provide new insight into cell cycle control by Rb-LIMD1 nexus. © 2014 International Federation for Cell Biology.

  5. Growth inhibition, cell-cycle alteration and apoptosis in stimulated human peripheral blood lymphocytes by multiwalled carbon nanotube buckypaper.

    Science.gov (United States)

    Zeni, Olga; Sannino, Anna; Romeo, Stefania; Micciulla, Federico; Bellucci, Stefano; Scarfi, Maria Rosaria

    2015-02-01

    This study was designed to investigate the cytotoxicity of multiwalled carbon nanotube buckypaper (BP) in stimulated human peripheral blood lymphocytes. Materials & methods & results: BP treatment led to a delay in the cell growth, as proven by a minor increase in the cell number over time relative to that seen in untreated cells, assessed by trypan blue, resazurin and neutral red assays. The analysis of cell-cycle profile, by propidium iodide staining, indicated that BP treatment blocked cell-cycle progression by arresting cells at the G0/G1 phase. Moreover, increased apoptosis was also recorded by Annexin V-fluorescein isothiocyanate/propidium iodide staining. The results presented here demonstrate an inhibitor effect of BP on cell growth that was likely through cytostatic and cytotoxic events.

  6. KOH concentration effect on cycle life of nickel-hydrogen cells

    Science.gov (United States)

    Lim, Hong S.; Verzwyvelt, S. A.

    1987-01-01

    A cycle life test of Ni/H2 cells containing electrolytes of various KOH concentrations and a sintered type nickel electrode was carried out at 23 C using a 45 min accelerated low Earth orbit (LEO) cycle regime at 80 percent depth of discharge. One of three cells containing 26 percent KOH has achieved over 28,000 cycles, and the other two 19,000 cycles, without a sign of failure. Two other cells containing 31 percent KOH electrolyte, which is the concentration presently used in aerospace cells, failed after 2,979 and 3,620 cycles. This result indicates that the cycle life of the present type of Ni/H2 cells may be extended by a factor of 5 to 10 simply by lowering the KOH concentration. Long cycle life of a Ni/H2 battery at high depth-of-discharge operation is desired, particularly for an LEO spacecraft application. Typically, battery life of about 30,000 cycles is required for a five year mission in an LEO. Such a cycle life with presently available cells can be assured only at a very low depth-of-discharge operation. Results of testing already show that the cycle life of an Ni/H2 cell is tremendously improved by simply using an electrolyte of low KOH concentration.

  7. PDK1 regulates VDJ recombination, cell-cycle exit and survival during B-cell development.

    Science.gov (United States)

    Venigalla, Ram K C; McGuire, Victoria A; Clarke, Rosemary; Patterson-Kane, Janet C; Najafov, Ayaz; Toth, Rachel; McCarthy, Pierre C; Simeons, Frederick; Stojanovski, Laste; Arthur, J Simon C

    2013-04-03

    Phosphoinositide-dependent kinase-1 (PDK1) controls the activation of a subset of AGC kinases. Using a conditional knockout of PDK1 in haematopoietic cells, we demonstrate that PDK1 is essential for B cell development. B-cell progenitors lacking PDK1 arrested at the transition of pro-B to pre-B cells, due to a cell autonomous defect. Loss of PDK1 decreased the expression of the IgH chain in pro-B cells due to impaired recombination of the IgH distal variable segments, a process coordinated by the transcription factor Pax5. The expression of Pax5 in pre-B cells was decreased in PDK1 knockouts, which correlated with reduced expression of the Pax5 target genes IRF4, IRF8 and Aiolos. As a result, Ccnd3 is upregulated in PDK1 knockout pre-B cells and they have an impaired ability to undergo cell-cycle arrest, a necessary event for Ig light chain rearrangement. Instead, these cells underwent apoptosis that correlated with diminished expression of the pro-survival gene Bcl2A1. Reintroduction of both Pax5 and Bcl2A1 together into PDK1 knockout pro-B cells restored their ability to differentiate in vitro into mature B cells.

  8. AS160 controls eukaryotic cell cycle and proliferation by regulating the CDK inhibitor p21.

    Science.gov (United States)

    Gongpan, Pianchou; Lu, Yanting; Wang, Fang; Xu, Yuhui; Xiong, Wenyong

    2016-07-02

    AS160 (TBC1D4) has been implicated in multiple biological processes. However, the role and the mechanism of action of AS160 in the regulation of cell proliferation remain unclear. In this study, we demonstrated that AS160 knockdown led to blunted cell proliferation in multiple cell types, including fibroblasts and cancer cells. The results of cell cycle analysis showed that these cells were arrested in the G1 phase. Intriguingly, this inhibition of cell proliferation and the cell cycle arrest caused by AS160 depletion were glucose independent. Moreover, AS160 silencing led to a marked upregulation of the expression of the cyclin-dependent kinase inhibitor p21. Furthermore, whereas AS160 overexpression resulted in p21 downregulation and rescued the arrested cell cycle in AS160-depeleted cells, p21 silencing rescued the inhibited cell cycle and proliferation in the cells. Thus, our results demonstrated that AS160 regulates glucose-independent eukaryotic cell proliferation through p21-dependent control of the cell cycle, and thereby revealed a molecular mechanism of AS160 modulation of cell cycle and proliferation that is of general physiological significance.

  9. Immunodetection of aquaporin 5 in sheep salivary glands related to pasture vegetative cycle

    Directory of Open Access Journals (Sweden)

    Silvana Arrighi

    2011-10-01

    Full Text Available Mammalian aquaporins (AQPs are a family of at least 13 integral membrane proteins expressed in various epithelia, where they function as channels to permeate water and small solutes. AQP5 is widely expressed in the exocrine gland where it is likely involved in providing an appropriate amount of fluid to be secreted with granular contents. As regards AQP5 expression in the salivary glands, literature is lacking concerning domestic animal species. This study was chiefly aimed at immunohistochemically investigating the presence and localization of AQP5 in sheep mandibular and parotid glands. In addition, AQP5 immunoreactivity was comparatively evaluated in animals fed with forage containing different amounts of water related to the pasture vegetative cycle, in order to shed light on the possible response of the gland to environmental modifications. Moderate AQP5-immunoreactivity was shown at the level of the lateral surface of mandibular serous demilune cells, not affected by the pasture vegetative cycle or water content. On the contrary, the parotid gland arcinar cells showed AQP5-immunoreactivity at the level of apical and lateral plasma membrane, which was slight to very strong, according to the pasture vegetative development and interannual climatic variations. AQP5 expression is likely due to its involvement in providing appropriate saliva fluidity. Indeed, the lowest AQP5 immunoreactivity was noticed when food water content increased. (Folia Histochemica et Cytobiologica 2011; Vol. 49, No. 3, pp. 458–464

  10. Cell cycle regulation and radiation-induced cell death; Regulation du cycle cellulaire et de la mort cellulaire radio-induite

    Energy Technology Data Exchange (ETDEWEB)

    Favaudon, V. [Centre Universitaire d' Orsay, Institut Curie, Section de Recherche, Lab. Raymond-Latarjet, Unite 350 Inserm, 91 (France)

    2000-10-01

    Tight control of cell proliferation is mandatory to prevent cancer formation as well as to normal organ development and homeostasis. This occurs through checkpoints that operate in both time and space and are involved in the control of numerous pathways including DNA replication and transcription, cell cycle progression, signal transduction and differentiation. Moreover, evidence has accumulated to show that apoptosis is tightly connected with the regulation of cell cycle progression. In this paper we describe the main pathways that determine checkpoints in the cell cycle and apoptosis. It is also recalled that in solid tumors radiation-induced cell death occurs most frequently through non-apoptotic mechanisms involving oncosis, and mitotic or delayed cell death. (author)

  11. Cell division cycle 20 overexpression predicts poor prognosis for patients with lung adenocarcinoma.

    Science.gov (United States)

    Shi, Run; Sun, Qi; Sun, Jing; Wang, Xin; Xia, Wenjie; Dong, Gaochao; Wang, Anpeng; Jiang, Feng; Xu, Lin

    2017-03-01

    The cell division cycle 20, a key component of spindle assembly checkpoint, is an essential activator of the anaphase-promoting complex. Aberrant expression of cell division cycle 20 has been detected in various human cancers. However, its clinical significance has never been deeply investigated in non-small-cell lung cancer. By analyzing The Cancer Genome Atlas database and using some certain online databases, we validated overexpression of cell division cycle 20 in both messenger RNA and protein levels, explored its clinical significance, and evaluated the prognostic role of cell division cycle 20 in non-small-cell lung cancer. Cell division cycle 20 expression was significantly correlated with sex (p = 0.003), histological classification (p overexpression of cell division cycle 20 was significantly associated with bigger primary tumor size (p = 0.0023), higher MKI67 level (r = 0.7618, p Overexpression of cell division cycle 20 is associated with poor prognosis in lung adenocarcinoma patients, and its overexpression can also be used to identify high-risk groups. In conclusion, cell division cycle 20 might serve as a potential biomarker for lung adenocarcinoma patients.

  12. Dissect the Dynamic Molecular Circuits of Cell Cycle Control through Network Evolution Model

    Directory of Open Access Journals (Sweden)

    Yang Peng

    2017-01-01

    Full Text Available The molecular circuits of cell cycle control serve as a key hub to integrate from endogenous and environmental signals into a robust biological decision driving cell growth and division. Dysfunctional cell cycle control is highlighted in a wide spectrum of human cancers. More importantly the mainstay anticancer treatment such as radiation therapy and chemotherapy targets the hallmark of uncontrolled cell proliferation in cancer cells by causing DNA damage, cell cycle arrest, and cell death. Given the functional importance of cell cycle control, the regulatory mechanisms that drive the cell division have been extensively investigated in a huge number of studies by conventional single-gene approaches. However the complexity of cell cycle control renders a significant barrier to understand its function at a network level. In this study, we used mathematical modeling through modern graph theory and differential equation systems. We believe our network evolution model can help us understand the dynamic cell cycle control in tumor evolution and optimizing dosing schedules for radiation therapy and chemotherapy targeting cell cycle.

  13. VRK1 regulates Cajal body dynamics and protects coilin from proteasomal degradation in cell cycle.

    Science.gov (United States)

    Cantarero, Lara; Sanz-García, Marta; Vinograd-Byk, Hadar; Renbaum, Paul; Levy-Lahad, Ephrat; Lazo, Pedro A

    2015-06-12

    Cajal bodies (CBs) are nuclear organelles associated with ribonucleoprotein functions and RNA maturation. CBs are assembled on coilin, its main scaffold protein, in a cell cycle dependent manner. The Ser-Thr VRK1 (vaccinia-related kinase 1) kinase, whose activity is also cell cycle regulated, interacts with and phosphorylates coilin regulating assembly of CBs. Coilin phosphorylation is not necessary for its interaction with VRK1, but it occurs in mitosis and regulates coilin stability. Knockdown of VRK1 or VRK1 inactivation by serum deprivation causes a loss of coilin phosphorylation in Ser184 and of CBs formation, which are rescued with an active VRK1, but not by kinase-dead VRK1. The phosphorylation of coilin in Ser184 occurs during mitosis before assembly of CBs. Loss of coilin phosphorylation results in disintegration of CBs, and of coilin degradation that is prevented by proteasome inhibitors. After depletion of VRK1, coilin is ubiquitinated in nuclei, which is partly mediated by mdm2, but its proteasomal degradation occurs in cytosol and is prevented by blocking its nuclear export. We conclude that VRK1 is a novel regulator of CBs dynamics and stability in cell cycle by protecting coilin from ubiquitination and degradation in the proteasome, and propose a model of CB dynamics.

  14. [Effect of starvation-induced autophagy on cell cycle of tumor cells].

    Science.gov (United States)

    Ge, Jun-Na; Huang, Dan; Xiao, Tian; Wang, Zun; Li, Xiao-Lan; Xiao, Hui; Tao, De-Ding; Gong, Jian-Ping

    2008-08-01

    No serum starvation could induce autophagy and cell cycle arrest. Although autophagy and cell cycle have been widely explored, little is known about their relationship. This study was to observe the change of Cyclin expression during starvation-induced autophagy to discuss the effect of autophagy on cell cycle. In control group, HeLa cells were treated with d-Hanks solution (a medium with no serum). In experiment group, HeLa cells were treated with d-Hanks solution containing 3-methyladenine (3-MA, a specific inhibitor of autophagy). Cells were harvested after being starved for 0, 3, 6 and 12 h. Flow cytometry (FCM) and Weston blot were used to detect Cyclin and microtubule-associated protein 1 light chain 3(LC-3) which marked autophagy specifically. In control group, the expression of LC-3 protein was detected early after being starved for 3 h, and gradually increased along with starvation; the expression of Cyclin D3 and Cyclin E was decreased evidently after a short-time starvation (3 h) and descended to the minimum when cells were being starved for 6 h; the expression of Cyclin A and Cyclin B1 were apparently decreased after being starved for 6 h. In experiment group, LC-3 protein could not be detected during starvation when cells were exposed to 3-MA and the down-regulation of Cyclins was suppressed. Autophagy is involved in starvation-induced hydrolysis of Cyclins. The hydrolysis of Cyclin D3 and Cyclin E is quicker than that of Cyclin A and Cyclin B1.

  15. Expression of proliferation markers and cell cycle regulators in T cell lymphoproliferative skin disorders.

    Science.gov (United States)

    Gambichler, Thilo; Bischoff, Stefan; Bechara, Falk G; Altmeyer, Peter; Kreuter, Alexander

    2008-02-01

    Abnormal cell proliferation, which results from deregulation of the cell cycle, is fundamental in tumorigenesis. To investigate the expression of proliferation markers and cell cycle regulators in a range of T cell lymphoproliferative skin diseases. We studied skin specimens of 51 patients with parapsoriasis (PP), mycosis fungiodes (MF), or lymphomatoid papulosis (LyP). Immunohistochemistry was performed for Ki-67, proliferating cell nuclear antigen (PCNA), minichromosome maintenance protein 7 (MCM7), and p21. MF with stage IIB-IV and LyP showed a significantly greater number of Ki-67-positive cells than PP (P=0.02 and 0.001) and MF I-IIA (P=0.019 and 0.003), respectively. MCM7 staining revealed significantly higher labeling indices for MF IIB-IV and LyP when compared to PP (P=0.002 and 0.04) and MF I-IIA (P=0.0005 and 0.01), respectively. Compared to PP and MF I-IIA, MF IIB-IV was associated with significantly higher labeling indices for PCNA (P=0.006 and 0.0004). p21 staining was significantly increased in MF IIB-IV and LyP when compared to PP (P=0.006 and 0.003) and MF I-IIA (P=0.003). However, p21 staining was all in all very weak. Ki-67 and PCNA seem to be useful immunohistological parameters for the correlation with the clinical stage of MF. In the differentiation and prognostication of T cell lymphoproliferative skin disorders, MCM7 may serve as a novel biomarker which is, in contrast to Ki-67 and PCNA, stable throughout the cell cycle.

  16. Emerging role of LRRK2 in human neural progenitor cell cycle progression, survival and differentiation

    Directory of Open Access Journals (Sweden)

    Meyer Anne K

    2009-06-01

    Full Text Available Abstract Despite a comprehensive mapping of the Parkinson's disease (PD-related mRNA and protein leucine-rich repeat kinase 2 (LRRK2 in the mammalian brain, its physiological function in healthy individuals remains enigmatic. Based on its structural features and kinase properties, LRRK2 may interact with other proteins involved in signalling pathways. Here, we show a widespread LRRK2 mRNA and/or protein expression in expanded or differentiated human mesencephalic neural progenitor cells (hmNPCs and in post-mortem substantia nigra PD patients. Using small interfering RNA duplexes targeting LRRK2 in hmNPCs following their differentiation into glia and neurons, we observed a reduced number of dopaminergic neurons due to apoptosis in LRRK2 knockdown samples. LRRK2-deficient hmNPCs exhibited elevated cell cycle- and cell death-related markers. In conclusion, a reduction of LRRK2 expression in hmNPCs severely impaired dopaminergic differentiation and/or survival of dopaminergic neurons most likely via preserving or reactivating the cell cycle.

  17. Study of the G2/M cell cycle checkpoint in irradiated mammary epithelial cells overexpressing Cul-4A gene

    International Nuclear Information System (INIS)

    Gupta, Anu; Yang, L.-X.; Chen, L.-C.

    2002-01-01

    Purpose: Members of the cullin gene family are known to be involved in cell cycle control. One of the cullin genes, Cul-4A, is amplified and overexpressed in breast cancer cells. This study investigates the effect of Cul-4A overexpression upon G2/M cell cycle checkpoint after DNA damage induced by either ionizing or nonionizing radiation. Methods and Materials: The normal mammary epithelial cell line MCF10A was stably transfected with full-length Cul-4A cDNA. Independent clones of MCF10A cells that overexpress Cul-4A proteins were selected and treated with either 8 Gy of ionizing radiation or 7 J/M 2 of UV radiation. The profile of cell cycle progression and the accumulation of several cell cycle proteins were analyzed. Results: We found that overexpression of Cul-4A in MCF10A cells abrogated the G2/M cell cycle checkpoint in response to DNA damage induced by ionizing irradiation, but not to DNA damage induced by nonionizing radiation. Analysis of cell cycle proteins showed that after ionizing irradiation, p53 accumulated in the mock-transfected MCF10A cells, but not in the Cul-4A transfectants. Conclusion: Our results suggest a role for Cul-4A in tumorigenesis and/or tumor progression, possibly through disruption of cell cycle control

  18. Quantitative trait loci mapping reveals candidate pathways regulating cell cycle duration in Plasmodium falciparum

    Directory of Open Access Journals (Sweden)

    Siwo Geoffrey

    2010-10-01

    Full Text Available Abstract Background Elevated parasite biomass in the human red blood cells can lead to increased malaria morbidity. The genes and mechanisms regulating growth and development of Plasmodium falciparum through its erythrocytic cycle are not well understood. We previously showed that strains HB3 and Dd2 diverge in their proliferation rates, and here use quantitative trait loci mapping in 34 progeny from a cross between these parent clones along with integrative bioinformatics to identify genetic loci and candidate genes that control divergences in cell cycle duration. Results Genetic mapping of cell cycle duration revealed a four-locus genetic model, including a major genetic effect on chromosome 12, which accounts for 75% of the inherited phenotype variation. These QTL span 165 genes, the majority of which have no predicted function based on homology. We present a method to systematically prioritize candidate genes using the extensive sequence and transcriptional information available for the parent lines. Putative functions were assigned to the prioritized genes based on protein interaction networks and expression eQTL from our earlier study. DNA metabolism or antigenic variation functional categories were enriched among our prioritized candidate genes. Genes were then analyzed to determine if they interact with cyclins or other proteins known to be involved in the regulation of cell cycle. Conclusions We show that the divergent proliferation rate between a drug resistant and drug sensitive parent clone is under genetic regulation and is segregating as a complex trait in 34 progeny. We map a major locus along with additional secondary effects, and use the wealth of genome data to identify key candidate genes. Of particular interest are a nucleosome assembly protein (PFL0185c, a Zinc finger transcription factor (PFL0465c both on chromosome 12 and a ribosomal protein L7Ae-related on chromosome 4 (PFD0960c.

  19. Methamphetamine induces hepatotoxicity via inhibiting cell division, arresting cell cycle and activating apoptosis: In vivo and in vitro studies.

    Science.gov (United States)

    Wang, Qi; Wei, Li-Wen; Xiao, Huan-Qin; Xue, Ye; Du, Si-Hao; Liu, Yun-Gang; Xie, Xiao-Li

    2017-07-01

    Methamphetamine (METH) resulted in acute hepatic injury. However, the underlying mechanisms have not been fully clarified. In the present study, rats were treated with METH (15 mg/kg B.W.) for 8 injections (i.p.), and the levels of alanine transaminase, asparatate transaminase and ammonia in serum were significantly elevated over those in the control group, suggesting hepatic injury, which was evidenced by histopathological observation. Analysis of the liver tissues with microarray revealed differential expressions of a total of 332 genes in METH-treated rats. According to the GO and KEGG annotations, a large number of down-regulated cell cycle genes were screened out, suggesting that METH induced cell cycle arrest and deficient of cell cycle checkpoint. Related genes and proteins were confirmed by RT-qPCR and western blotting in rat livers, respectively. Moreover, treatment of Brl-3A cells with METH caused significant cytotoxic response and marked cell cycle arrest. Furthermore, overexpressions of Cidea, cleaved caspase 3 and PARP 1 in METH-treated rats indicated activation of apoptosis, while its inhibition alleviated cell death in Brl-3A cells, suggesting that activation of apoptosis took an important role in METH-induced hepatotoxicity. Taken together, the present study demonstrates that METH induced hepatotoxicity via inducing cell cycle arrest and activating apoptosis. Copyright © 2017 Elsevier Ltd. All rights reserved.

  20. Effects of cyclin D1 gene silencing on cell proliferation, cell cycle, and apoptosis of hepatocellular carcinoma cells.

    Science.gov (United States)

    Chen, Jin; Li, Xue; Cheng, Qi; Ning, Deng; Ma, Jie; Zhang, Zhi-Ping; Chen, Xiao-Ping; Jiang, Li

    2018-02-01

    This study aims to investigate the effects of Cyclin D1 silencing on cell cycle, cell proliferation, and apoptosis of hepatocellular carcinoma cells (HCC). Cells were divided into the blank group, negative control group (HCC cells transfected with control shRNA), Cyclin D1 shRNA group (HCC cells transfected with Cyclin D1 shRNA), and the normal group (human normal liver L-02 cells). Expressions of Cyclin D1, Caspase-3, Bcl-2, and C-myc were detected by RT-qPCR and Western blotting. Cell proliferation was detected by Cell Counting Kit-8. Cell cycle and apoptosis were detected by flow cytometry. Tumor xenograft in nude mice was performed to detect in vivo tumorigenesis. HCC tissues and HCC cells exhibited elevated expression levels of Cyclin D1. Cyclin D1 expression levels was found to be correlated with tumor size and tumor staging. Compared with the normal group, the blank group showed enhanced cell proliferation, a reduction in the amount of cells in G0/G1 phase, increased number cells in S and G2/M phase, reduced apoptosis, elevated expressions of Cyclin D1, Bcl-2, and C-myc, decreased Caspase-3 activity and significant tumorigenicity. In comparison with the blank group, the Cyclin D1 shRNA group revealed weakened cell proliferation, reduced cells in S and G2/M phase, increased cells in G0/G1 phase, increased Annexin V positive cell ratio, decreased expression of Cyclin D1, Bcl-2, and C-myc, elevated Caspase-3 activity and inhibited tumorigenicity. In conclusion, Cyclin D1 gene silencing suppresses cell proliferation and inhibits cell apoptosis, which may be a new target approach in the treatment and management for HCC. © 2017 Wiley Periodicals, Inc.

  1. {gamma}-irradiation deregulates cell cycle control and apoptosis in nevoid basal cell carcinomas syndrome-derived cells

    Energy Technology Data Exchange (ETDEWEB)

    Fujii, Katsunori; Miyashita, Toshiyuki; Yamada, Masao [National Children' s Medical Research Center, Tokyo (Japan); Takanashi, Jun-ichi; Sugita, Katsuo; Kohno, Yoichi; Nishie, Haruko; Yasumoto, Shin-ichiro; Furue, Masutaka

    1999-12-01

    The nevoid basal cell carcinoma syndrome (NBCCS) is an autosomal dominant disorder characterized by nevi, palmar and plantar pits, falx calcification, vertebrate anomalies and basal cell carcinomas. It is well known in NBCCS that {gamma}-irradiation to the skin induces basal cell carcinomas or causes an enlargement of the tumor size, although the details of the mechanism remain unknown. We have established lymphoblastoid cell lines from three NBCCS patients, and we present here the first evidence of abnormal cell cycle and apoptosis regulations. A novel mutation (single nucleotide deletion) in the coding region of the human patched gene, PTCH, was identified in two sibling patients, but no apparent abnormalities were detected in the gene of the remaining patient. Nevertheless, the three established cell lines showed similar features in the following analyses. Flow cytometric analyses revealed that the NBCCS-derived cells were accumulated in the G{sub 2}M phase after {gamma}-irradiation, whereas normal cells showed cell cycle arrest both in the G{sub 0}G{sub 1} and G{sub 2}M phases. The fraction of apoptotic cells after {gamma}-irradiation was smaller in the NBCCS cells. The level of p27 expression markedly decreased after {gamma}-irradiation in the NBCCS cells, although the effects of the irradiation on the expression profiles for p53, p21 and Rb did not differ in normal and NBCCS cells. These findings may provide a clue to the molecular mechanisms of tumorigenesis in NBCCS. (author)

  2. Centchroman induces redox-dependent apoptosis and cell-cycle arrest in human endometrial cancer cells.

    Science.gov (United States)

    Shyam, Hari; Singh, Neetu; Kaushik, Shweta; Sharma, Ramesh; Balapure, Anil K

    2017-04-01

    Centchroman (CC) or Ormeloxifene has been shown to induce apoptosis and cell cycle arrest in various types of cancer cells. This has, however, not been addressed for endometrial cancer cells where its (CC) mechanism of action remains unclear. This study focuses on the basis of antineoplasticity of CC by blocking the targets involved in the cell cycle, survival and apoptosis in endometrial cancer cells. Ishikawa Human Endometrial Cancer Cells were cultured under estrogen deprived medium, exposed to CC and analyzed for proliferation and apoptosis. Additionally, we also analyzed oxidative stress induced by CC. Cell viability studies confirmed the IC 50 of CC in Ishikawa cells to be 20 µM after 48 h treatment. CC arrests the cells in G0/G1 phase through cyclin D1 and cyclin E mediated pathways. Phosphatidylserine externalization, nuclear morphology changes, DNA fragmentation, PARP cleavage, and alteration of Bcl-2 family protein expression clearly suggest ongoing apoptosis in the CC treated cells. Activation of caspase 3 & 9, up-regulation of AIF and inhibition of apoptosis by z-VAD-fmk clearly explains the participation of the intrinsic pathway of programmed cell death. Further, the increase of ROS, loss of MMP, inhibition of antioxidant (MnSOD, Cu/Zn-SOD and GST) and inhibition of apoptosis with L-NAC suggests CC induced oxidative stress leading to apoptosis via mitochondria mediated pathway. Therefore, CC could be a potential therapeutic agent for the treatment of Endometrial Cancer adjunct to its utility as a contraceptive and an anti-breast cancer agent.

  3. Analysis of cell-cycle regulation following exposure of lung-derived cells to γ-rays

    Science.gov (United States)

    Trani, D.; Lucchetti, C.; Cassone, M.; D'Agostino, L.; Caputi, M.; Giordano, A.

    Acute exposure of mammalian cells to ionizing radiation results in a delay of cell-cycle progression and/or augmentation of apoptosis. Following ionizing radiation-induced DNA damage, cell-cycle arrest in the G1- or G2-phase of the cell-cycle prevents or delays DNA replication or mitosis, providing time for the DNA repair machinery to exert its function. Deregulation or failing of cell-cycle checkpoints and/or DNA repair mechanisms may lead normal cells bearing chromosome mutations to acquire neoplastic autonomy, which in turn can trigger the onset of cancer. Existing studies have focused on the impact of p53 status on the radiation response of lung cancer (LC) cell lines in terms of both cell-cycle regulation and apoptosis, while no comparative studies have been performed on the radiation response of lung derived normal and cancerous epithelial cells. To investigate the radiation response in normal and cancerous phenotypes, along with the role and impact of p53 status, and possible correlations with pRb/p105 or other proteins involved in carcinogenesis and cell-cycle regulation, we selected two lung-derived epithelial cell lines, one normal (NL20, p53 wild-type) and one non-small cell lung cancer (NSCLC), H358 (known to be p53-deficient). We compared the levels of γ-induced cell proliferation ability, cell-cycle arrest, apoptotic index, and expression levels of cell-cycle regulating and regulated proteins. The different cell sensitivity, apoptotic response and protein expression profiles resulting from our study for NL20 and H358 cells suggest that still unknown mechanisms involving p53, pRb/p105 and their target molecules might play a pivotal role in determining cell sensitivity and resistance upon exposure to ionizing radiation.

  4. Effect of silencing HOXA5 gene expression using RNA interference on cell cycle and apoptosis in Jurkat cells.

    Science.gov (United States)

    Huang, Hui-Ping; Liu, Wen-Jun; Guo, Qu-Lian; Bai, Yong-Qi

    2016-03-01

    Acute lymphocytic leukemia (ALL) is a common malignant tumor with a high morbidity rate among children, accounting for approximately 80% of leukemia cases. Although there have been improvements in the treatment of patients frequent relapse lead to a poor prognosis. The aim of the present study was to determine whether HOXA5 may be used as a target for gene therapy in leukemia in order to provide a new treatment. Mononuclear cells were extracted from the bone marrow according to the clinical research aims. After testing for ALL in the acute stage, the relative mRNA and protein expression of HOXA5 was detected in the ALL remission groups (n=25 cases per group) and the control group [n=20 cases, immune thrombocytopenia (ITP)]. Gene silencing by RNA interference (RNAi) was used to investigate the effect of silencing HOXA5 after small interfering RNA (siRNA) transfection to Jurkat cells. The HOXA5-specific siRNA was transfected to Jurkat cells using lipofectamine. The experiment was divided into the experimental group (liposomal transfection of HOXA5 targeting siRNA), the negative control group (liposomal transfection of cells with negative control siRNA) and the control group (plus an equal amount of cells and culture media only). Western blotting and quantitative fluorescent polymerase chain reaction (QF‑PCR) were used to detect the relative HOXA5 mRNA expression and protein distribution in each cell group. Cell distribution in the cell cycle and the rate of cells undergoing apoptosis were determined using flow cytometry. The expression of HOXA5 at the mRNA and protein levels in the acute phase of ALL was significantly higher than that in ALL in the remission and control groups. In cells transfected with HOXA5-specific siRNA, the expression of HOXA5 at the mRNA and protein levels decreased significantly (PJurkat cells, thus inhibiting cell proliferation.

  5. Cell cycle arrest in a model of colistin nephrotoxicity

    Science.gov (United States)

    Hack, Bradley K.; Alexander, Jessy J.; Xu, Chang; Dolan, M. Eileen; Cunningham, Patrick N.

    2013-01-01

    Colistin (polymixin E) is an antibiotic prescribed with resurging frequency for multidrug resistant gram negative bacterial infections. It is associated with nephrotoxicity in humans in up to 55% of cases. Little is known regarding genes involved in colistin nephrotoxicity. A murine model of colistin-mediated kidney injury was developed. C57/BL6 mice were administered saline or colistin at a dose of 16 mg/kg/day in 2 divided intraperitoneal doses and killed after either 3 or 15 days of colistin. After 15 days, mice exposed to colistin had elevated blood urea nitrogen (BUN), creatinine, and pathologic evidence of acute tubular necrosis and apoptosis. After 3 days, mice had neither BUN elevation nor substantial pathologic injury; however, urinary neutrophil gelatinase-associated lipocalin was elevated (P = 0.017). An Illumina gene expression array was performed on kidney RNA harvested 72 h after first colistin dose to identify differentially expressed genes early in drug treatment. Array data revealed 21 differentially expressed genes (false discovery rate < 0.1) between control and colistin-exposed mice, including LGALS3 and CCNB1. The gene signature was significantly enriched for genes involved in cell cycle proliferation. RT-PCR, immunoblot, and immunostaining validated the relevance of key genes and proteins. This murine model offers insights into the potential mechanism of colistin-mediated nephrotoxicity. Further studies will determine whether the identified genes play a causative or protective role in colistin-induced nephrotoxicity. PMID:23922129

  6. Satellite cell number and cell cycle kinetics in response to acute myotrauma in humans: immunohistochemistry versus flow cytometry

    Science.gov (United States)

    McKay, Bryon R; Toth, Kyle G; Tarnopolsky, Mark A; Parise, Gianni

    2010-01-01

    In humans, muscle satellite cell (SC) enumeration is an important measurement used to determine the myogenic response to various stimuli. To date, the standard practice for enumeration is immunohistochemistry (IHC) using antibodies against common SC markers (Pax7, NCAM). Flow cytometry (FC) analysis may provide a more rapid and quantitative determination of changes in the SC pool with potential for additional analysis not easily achievable with standard IHC. In this study, FC analysis revealed that the number of Pax7+ cells per milligram isolated from ∼50 mg of fresh tissue increased 36% 24 h after exercise-induced muscle injury (300 unilateral maximal eccentric contractions). IHC analysis of Pax7 and neural cell adhesion molecule (NCAM) appeared to sufficiently and similarly represent the expansion of SCs after injury (28–36% increase). IHC and FC data illustrated that Pax7 was the most widely expressed SC marker in muscle cross-sections and represented the majority of positive cells, while NCAM was expressed to a lesser degree. Moreover, FC and IHC demonstrated a similar percentage change 24 h after injury (36% increase, Pax7; 28% increase, NCAM). FC analysis of isolated SCs revealed that the number of Pax7+ cells per milligram in G2/M phase of the cell cycle increased 202% 24 h after injury. Number of cells per milligram in G0/G1 and cells in S-phase increased 32% and 59% respectively. Here we illustrate the use of FC as a method for enumerating SC number on a per milligram tissue basis, providing a more easily understandable relation to muscle mass (vs. percentage of myonuclei or per myofibre). Although IHC is a powerful tool for SC analysis, FC is a fast, reliable and effective method for SC quantification as well as a more informative method for cell cycle kinetics of the SC population in humans. PMID:20624792

  7. Cell cycle analysis of brain cells as a growth index in larval cod at different feeding conditions and temperatures

    Directory of Open Access Journals (Sweden)

    Rafael González-Quirós

    2007-09-01

    Full Text Available The percentage of cells dividing in a specific tissue of individual larvae can be estimated by analyzing DNA per cell by flow cytometry. An experimental test was carried out with cod (Gadus morhua larvae, with brain as the target tissue, to validate this technique as an appropriate growth index for larval fish. Standard length (SL, myotome height, and %S-phase (% of cells in the S-phase of the cell-division cycle variability were analyzed, with temperature (6 and 10°C, food level (high- and no-food and larval developmental stage (first feeding, pre-metamorphosis and post-metamorphosis as independent factors. Cod larvae grew faster (in SL and presented a higher %S-phase under high-food conditions. Larval SL increased with temperature in rearing and experimental tanks. However, there was a significant interaction between temperature and food in the %S-phase. There were no significant differences in the %S-phase between 6 and 10°C at high-food levels. We suggest that this result is a consequence of temperature-dependency of the duration of the cell cycle. In the absence of food, larvae at 10ºC had a lower %S-phase than larvae at 6°C, which may be related to increased metabolic costs with increasing temperature. Considering the effect of temperature, the mean % S-phase explained 74% of the variability in the estimated standard growth rate.

  8. [Impact of stromal interaction molecule 1 silencing on cell cycle of endothelial progenitor cells].

    Science.gov (United States)

    Kuang, Chun-Yan; Huang, Lan; Yu, Yang; Deng, Meng-Yang; Wang, Kui; Qian, De-Hui

    2011-07-01

    To investigate the effect of stromal interaction molecule 1 (STIM1) silencing on EPCs cell cycle. Rat bone marrow derived endothelial progenitor cells (EPCs) were isolated and cultured in L-DMEM with 20% FBS. Ad-si/rSTIM1 and Ad-hSTIM1 were then transfected into EPCs and the expression of STIM1 mRNA was detected by RT-PCR. The cell cycle was determined using flow cytometry analysis and intracellular free Ca2+ was measured using LSCM. Co-immunoprecipitation was performed to examine the interaction between STIM1 and TRPC1. Protein levels of inositol 1, 4, 5-trisphosphate were analyzed with ELISA assay. Forty-eight hours after transfection, the expression of STIM1 mRNA was significantly downregulated (0.37 +/- 0.02 vs. 1.00 +/- 0.02, P si/rSTIM1 group compared with control group. The cell cycle was arrested at G1 phase [(90.91 +/- 1.10)% vs. (77.10 +/- 0.56)%, P si/rSTIM1. However, cotransfection of Ad-hSTIM1 with Ad-si/rSTIM1 significantly reversed these responses. Interestingly, co-immunoprecipitation study showed that STIM1 co-precipitated with TRPC1, and IP3 levels measured by ELISA were similar among three groups (P > 0.05). siRNA-mediated knockdown of STIM1 inhibited EPCs proliferation by reducing intracellular free Ca2+ through TRPC1-SOC signaling pathway.

  9. Cell-cycle calcium transients driven by cyclic changes in inositol trisphosphate levels.

    Science.gov (United States)

    Ciapa, B; Pesando, D; Wilding, M; Whitaker, M

    1994-04-28

    Transient changes in intracellular calcium ([Ca2+]i) have been shown to punctuate the cell cycle in various types of cells in culture and in early embryos. The [Ca2+]i transients are correlated with cell-cycle events: pronuclear migration, nuclear envelope breakdown, the metaphase-anaphase transition of mitosis, and cytokinesis. Mitotic events can be induced by injecting calcium and prevented by injecting calcium chelators into the sea urchin embryo. Cell-cycle calcium transients differ from the transients linked to membrane signal transduction pathways: they are generated by an endogenous mechanism, not by plasma membrane receptor complexes, and their trigger is unknown. We report here that the phosphoinositide messenger system oscillates during the early embryonic cell cycle in the sea urchin, leading to cyclic increases in inositol trisphosphate that trigger cell-cycle [Ca2+]i transients and mitosis by calcium release from intracellular stores.

  10. Cyclin D1 overexpression, cell cycle progression and radiosensitivity in MBP cells

    International Nuclear Information System (INIS)

    Wu Lijun; Yu Zengliang

    2000-11-01

    Clones that exhibited a minimum of 7-8 fold cyclin D1 level above the parent cell lines or the vector control were obtained after transfected with the entire coding sequence of human 1.1 kb cyclin D1 cDNA. Studies showed that there was no significant difference in Radiosensitivity between over-expressing cyclin D1 and control cultures from either mouse or human origin. Using flow cytometry to access cell cycle distribution in the exponentially growth cultures of MCF10F-D1-21 and MCF10F-V-3, it was found that there was a 50 percent increase in the proportion of G2/M phase cells and 5.3 percent decrease in the proportion of G0/G1 phase cells in MCF10F-D1-21 comparing with MCF10F-V-3, though they were with the same proportion of cells in S phase

  11. Proliferating cell nuclear antigen (PCNA): a key factor in DNA replication and cell cycle regulation.

    Science.gov (United States)

    Strzalka, Wojciech; Ziemienowicz, Alicja

    2011-05-01

    PCNA (proliferating cell nuclear antigen) has been found in the nuclei of yeast, plant and animal cells that undergo cell division, suggesting a function in cell cycle regulation and/or DNA replication. It subsequently became clear that PCNA also played a role in other processes involving the cell genome. This review discusses eukaryotic PCNA, with an emphasis on plant PCNA, in terms of the protein structure and its biochemical properties as well as gene structure, organization, expression and function. PCNA exerts a tripartite function by operating as (1) a sliding clamp during DNA synthesis, (2) a polymerase switch factor and (3) a recruitment factor. Most of its functions are mediated by its interactions with various proteins involved in DNA synthesis, repair and recombination as well as in regulation of the cell cycle and chromatid cohesion. Moreover, post-translational modifications of PCNA play a key role in regulation of its functions. Finally, a phylogenetic comparison of PCNA genes suggests that the multi-functionality observed in most species is a product of evolution. Most plant PCNAs exhibit features similar to those found for PCNAs of other eukaryotes. Similarities include: (1) a trimeric ring structure of the PCNA sliding clamp, (2) the involvement of PCNA in DNA replication and repair, (3) the ability to stimulate the activity of DNA polymerase δ and (4) the ability to interact with p21, a regulator of the cell cycle. However, many plant genomes seem to contain the second, probably functional, copy of the PCNA gene, in contrast to PCNA pseudogenes that are found in mammalian genomes.

  12. Radioprotection and Cell Cycle Arrest of Intestinal Epithelial Cells by Darinaparsin, a Tumor Radiosensitizer

    Energy Technology Data Exchange (ETDEWEB)

    Tian, Junqiang; Doi, Hiroshi [Department of Radiation Oncology, School of Medicine, Stanford University, Stanford, California (United States); Saar, Matthias; Santos, Jennifer [Department of Urology, School of Medicine, Stanford University, Stanford, California (United States); Li, Xuejun; Peehl, Donna M. [Department of Radiation Oncology, School of Medicine, Stanford University, Stanford, California (United States); Knox, Susan J., E-mail: sknox@stanford.edu [Department of Radiation Oncology, School of Medicine, Stanford University, Stanford, California (United States)

    2013-12-01

    Purpose: It was recently reported that the organic arsenic compound darinaparsin (DPS) is a cytotoxin and radiosensitizer of tumor cells in vitro and in subcutaneous xenograft tumors. Surprisingly, it was also found that DPS protects normal intestinal crypt epithelial cells (CECs) from clonogenic death after ionizing radiation (IR). Here we tested the DPS radiosensitizing effect in a clinically relevant model of prostate cancer and explored the radioprotective effect and mechanism of DPS on CECs. Methods and Materials: The radiation modification effect of DPS was tested in a mouse model of orthotopic xenograft prostate cancer and of IR-induced acute gastrointestinal syndrome. The effect of DPS on CEC DNA damage and DNA damage responses was determined by immunohistochemistry. Results: In the mouse model of IR-induced gastrointestinal syndrome, DPS treatment before IR accelerated recovery from body weight loss and increased animal survival. DPS decreased post-IR DNA damage and cell death, suggesting that the radioprotective effect was mediated by enhanced DNA damage repair. Shortly after DPS injection, significant cell cycle arrest was observed in CECs at both G1/S and G2/M checkpoints, which was accompanied by the activation of cell cycle inhibitors p21 and growth arrest and DNA-damage-inducible protein 45 alpha (GADD45A). Further investigation revealed that DPS activated ataxia telangiectasia mutated (ATM), an important inducer of DNA damage repair and cell cycle arrest. Conclusions: DPS selectively radioprotected normal intestinal CECs and sensitized prostate cancer cells in a clinically relevant model. This effect may be, at least in part, mediated by DNA damage response activation and has the potential to significantly increase the therapeutic index of radiation therapy.

  13. Radioprotection and Cell Cycle Arrest of Intestinal Epithelial Cells by Darinaparsin, a Tumor Radiosensitizer

    International Nuclear Information System (INIS)

    Tian, Junqiang; Doi, Hiroshi; Saar, Matthias; Santos, Jennifer; Li, Xuejun; Peehl, Donna M.; Knox, Susan J.

    2013-01-01

    Purpose: It was recently reported that the organic arsenic compound darinaparsin (DPS) is a cytotoxin and radiosensitizer of tumor cells in vitro and in subcutaneous xenograft tumors. Surprisingly, it was also found that DPS protects normal intestinal crypt epithelial cells (CECs) from clonogenic death after ionizing radiation (IR). Here we tested the DPS radiosensitizing effect in a clinically relevant model of prostate cancer and explored the radioprotective effect and mechanism of DPS on CECs. Methods and Materials: The radiation modification effect of DPS was tested in a mouse model of orthotopic xenograft prostate cancer and of IR-induced acute gastrointestinal syndrome. The effect of DPS on CEC DNA damage and DNA damage responses was determined by immunohistochemistry. Results: In the mouse model of IR-induced gastrointestinal syndrome, DPS treatment before IR accelerated recovery from body weight loss and increased animal survival. DPS decreased post-IR DNA damage and cell death, suggesting that the radioprotective effect was mediated by enhanced DNA damage repair. Shortly after DPS injection, significant cell cycle arrest was observed in CECs at both G1/S and G2/M checkpoints, which was accompanied by the activation of cell cycle inhibitors p21 and growth arrest and DNA-damage-inducible protein 45 alpha (GADD45A). Further investigation revealed that DPS activated ataxia telangiectasia mutated (ATM), an important inducer of DNA damage repair and cell cycle arrest. Conclusions: DPS selectively radioprotected normal intestinal CECs and sensitized prostate cancer cells in a clinically relevant model. This effect may be, at least in part, mediated by DNA damage response activation and has the potential to significantly increase the therapeutic index of radiation therapy

  14. Effects of arsenite on cell cycle progression in a human bladder cancer cell line

    International Nuclear Information System (INIS)

    Hernandez-Zavala, A.; Cordova, E.; Razo, L.M. del; Cebrian, M.E.; Garrido, E.

    2005-01-01

    Bladder cancer is one of the most important diseases associated with arsenic (As) exposure in view of its high prevalence and mortality rate. Experimental studies have shown that As exposure induces cell proliferation in the bladder of sodium arsenite (iAsIII) subchronically treated mice. However, there is little available information on its effects on the cell cycle of bladder cells. Thus, our purpose was to evaluate the effects of iAsIII on cell cycle progression and the response of p53 and p21 on the human-derived epithelial bladder cell line HT1197. iAsIII treatment (1-10 μM) for 24 h induced a dose-dependent increase in the proportion of cells in S-phase, which reached 65% at the highest dose. A progressive reduction in cell proliferation was also observed. BrdU was incorporated to cellular DNA in an interrupted form, suggesting an incomplete DNA synthesis. The time-course of iAsIII effects (10 μM) showed an increase in p53 protein content and a transient increase in p21 protein levels accompanying the changes in S-phase. These effects were correlated with iAs concentrations inside the cells, which were not able to metabolize inorganic arsenic. Our findings suggest that p21 was not able to block CDK2-cyclin E complex activity and was therefore unable to arrest cells in G1 allowing their progression into the S-phase. Further studies are needed to ascertain the mechanisms underlying the effects of iAsIII on the G1 to S phase transition in bladder cells

  15. Effect of KOH concentration on LEO cycle life of IPV nickel-hydrogen flight battery cells

    Science.gov (United States)

    Smithrick, John J.; Hall, Stephen W.

    1990-01-01

    A breakthrough in the low-earth-orbit (LEO) cycle life of individual pressure vessel (IPV) nickel hydrogen battery cells is reported. The cycle life of boiler plate cells containing 26 percent potassium hydroxide (KOH) electrolyte was about 40,000 LEO cycles compared to 3500 cycles for cells containing 31 percent KOH. The effect of KOH concentration on cycle life was studied. The cycle regime was a stressful accelerated LEO, which consisted of a 27.5 min charge followed by a 17.5 min charge (2 x normal rate). The depth of discharge (DOD) was 80 percent. The cell temperature was maintained at 23 C. The next step is to validate these results using flight hardware and real time LEO test. NASA Lewis has a contract with the Naval Weapons Support Center (NWSC), Crane, Indiana to validate the boiler plate test results. Six 48 A-hr Hughes recirculation design IPV nickel-hydrogen flight battery cells are being evaluated. Three of the cells contain 26 percent KOH (test cells) and three contain 31 percent KOH (control cells). They are undergoing real time LEO cycle life testing. The cycle regime is a 90-min LEO orbit consisting of a 54-min charge followed by a 36-min discharge. The depth-of-discharge is 80 percent. The cell temperature is maintained at 10 C. The cells were cycled for over 8000 cycles in the continuing test. There were no failures for the cells containing 26 percent KOH. There were two failures, however, for the cells containing 31 percent KOH.

  16. WNT Takes Two to Tango: Molecular Links between the Circadian Clock and the Cell Cycle in Adult Stem Cells.

    Science.gov (United States)

    Matsu-Ura, Toru; Moore, Sean R; Hong, Christian I

    2018-02-01

    Like two dancers, the circadian clock and cell cycle are biological oscillators engaged in bidirectional communication, resulting in circadian clock-gated cell division cycles in species ranging from cyanobacteria to mammals. The identified mechanisms for this phenomenon have expanded beyond intracellular molecular coupling components to include intercellular connections. However, detailed molecular mechanisms, dynamics, and physiological functions of the circadian clock and cell cycle as coupled oscillators remain largely unknown. In this review, we discuss current understanding of this connection in light of recent findings that have uncovered intercellular coupling between the circadian clock in Paneth cells and the cell cycle in intestinal stem cells via WNT signaling. This extends the impact of circadian rhythms regulating the timing of cell divisions beyond the intracellular domain of homogenous cell populations into dynamic, multicellular systems. In-depth understanding of the molecular links and dynamics of these two oscillators will identify potential targets and temporal regimens for effective chronotherapy.

  17. Clonally Diverse T Cell Homeostasis Is Maintained by a Common Program of Cell-Cycle Control

    Science.gov (United States)

    Hogan, Thea; Shuvaev, Andrey; Commenges, Daniel; Yates, Andrew; Callard, Robin

    2013-01-01

    Lymphopenia induces T cells to undergo cell divisions as part of a homeostatic response mechanism. The clonal response to lymphopenia is extremely diverse, and it is unknown whether this heterogeneity represents distinct mechanisms of cell-cycle control or whether a common mechanism can account for the diversity. We addressed this question by combining in vivo and mathematical modeling of lymphopenia-induced proliferation (LIP) of two distinct T cell clonotypes. OT-I T cells undergo rapid LIP accompanied by differentiation that superficially resembles Ag-induced proliferation, whereas F5 T cells divide slowly and remain naive. Both F5 and OT-I LIP responses were most accurately described by a single stochastic division model where the rate of cell division was exponentially decreased with increasing cell numbers. The model successfully identified key biological parameters of the response and accurately predicted the homeostatic set point of each clone. Significantly, the model was successful in predicting interclonal competition between OT-I and F5 T cells, consistent with competition for the same resource(s) required for homeostatic proliferation. Our results show that diverse and heterogenous clonal T cell responses can be accounted for by a single common model of homeostasis. PMID:23475214

  18. Cell cycle age dependence for radiation-induced G2 arrest: evidence for time-dependent repair

    International Nuclear Information System (INIS)

    Rowley, R.

    1985-01-01

    Exponentially growing eucaryotic cells, irradiated in interphase, are delayed in progression to mitosis chiefly by arrest in G 2 . The sensitivity of Chinese hamster ovary cells to G 2 arrest induction by X rays increases through the cell cycle, up to the X-ray transition point (TP) in G 2 . This age response can be explained by cell cycle age-dependent changes in susceptibility of the target(s) for G 2 arrest and/or by changes in capability for postirradiation recovery from G 2 arrest damage. Discrimination between sensitivity changes and repair phenomena is possible only if the level of G 2 arrest-causing damage sustained by a cell at the time of irradiation and the level ultimately expressed as arrest can be determined. The ability of caffeine to ameliorate radiation-induced G 2 arrest, while inhibiting repair of G 2 arrest-causing damage makes such an analysis possible. In the presence of caffeine, progression of irradiated cells was relatively unperturbed, but on caffeine removal, G 2 arrest was expressed. The duration of G 2 arrest was independent of the length of the prior caffeine exposure. This finding indicates that the target for G 2 arrest induction is present throughout the cell cycle and that the level of G 2 arrest damage incurred is initially constant for all cell cycle phases. The data are consistent with the existence of a time-dependent recovery mechanism to explain the age dependence for radiation induction of G 2 arrest

  19. RPS27a promotes proliferation, regulates cell cycle progression and inhibits apoptosis of leukemia cells

    International Nuclear Information System (INIS)

    Wang, Houcai; Yu, Jing; Zhang, Lixia; Xiong, Yuanyuan; Chen, Shuying; Xing, Haiyan; Tian, Zheng; Tang, Kejing; Wei, Hui; Rao, Qing; Wang, Min; Wang, Jianxiang

    2014-01-01

    Highlights: • RPS27a expression was up-regulated in advanced-phase CML and AL patients. • RPS27a knockdown changed biological property of K562 and K562/G01 cells. • RPS27a knockdown affected Raf/MEK/ERK, P21 and BCL-2 signaling pathways. • RPS27a knockdown may be applicable for new combination therapy in CML patients. - Abstract: Ribosomal protein S27a (RPS27a) could perform extra-ribosomal functions besides imparting a role in ribosome biogenesis and post-translational modifications of proteins. The high expression level of RPS27a was reported in solid tumors, and we found that the expression level of RPS27a was up-regulated in advanced-phase chronic myeloid leukemia (CML) and acute leukemia (AL) patients. In this study, we explored the function of RPS27a in leukemia cells by using CML cell line K562 cells and its imatinib resistant cell line K562/G01 cells. It was observed that the expression level of RPS27a was high in K562 cells and even higher in K562/G01 cells. Further analysis revealed that RPS27a knockdown by shRNA in both K562 and K562G01 cells inhibited the cell viability, induced cell cycle arrest at S and G2/M phases and increased cell apoptosis induced by imatinib. Combination of shRNA with imatinib treatment could lead to more cleaved PARP and cleaved caspase-3 expression in RPS27a knockdown cells. Further, it was found that phospho-ERK(p-ERK) and BCL-2 were down-regulated and P21 up-regulated in RPS27a knockdown cells. In conclusion, RPS27a promotes proliferation, regulates cell cycle progression and inhibits apoptosis of leukemia cells. It appears that drugs targeting RPS27a combining with tyrosine kinase inhibitor (TKI) might represent a novel therapy strategy in TKI resistant CML patients

  20. RPS27a promotes proliferation, regulates cell cycle progression and inhibits apoptosis of leukemia cells

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Houcai; Yu, Jing; Zhang, Lixia; Xiong, Yuanyuan; Chen, Shuying; Xing, Haiyan; Tian, Zheng; Tang, Kejing; Wei, Hui; Rao, Qing; Wang, Min; Wang, Jianxiang, E-mail: wangjx@ihcams.ac.cn

    2014-04-18

    Highlights: • RPS27a expression was up-regulated in advanced-phase CML and AL patients. • RPS27a knockdown changed biological property of K562 and K562/G01 cells. • RPS27a knockdown affected Raf/MEK/ERK, P21 and BCL-2 signaling pathways. • RPS27a knockdown may be applicable for new combination therapy in CML patients. - Abstract: Ribosomal protein S27a (RPS27a) could perform extra-ribosomal functions besides imparting a role in ribosome biogenesis and post-translational modifications of proteins. The high expression level of RPS27a was reported in solid tumors, and we found that the expression level of RPS27a was up-regulated in advanced-phase chronic myeloid leukemia (CML) and acute leukemia (AL) patients. In this study, we explored the function of RPS27a in leukemia cells by using CML cell line K562 cells and its imatinib resistant cell line K562/G01 cells. It was observed that the expression level of RPS27a was high in K562 cells and even higher in K562/G01 cells. Further analysis revealed that RPS27a knockdown by shRNA in both K562 and K562G01 cells inhibited the cell viability, induced cell cycle arrest at S and G2/M phases and increased cell apoptosis induced by imatinib. Combination of shRNA with imatinib treatment could lead to more cleaved PARP and cleaved caspase-3 expression in RPS27a knockdown cells. Further, it was found that phospho-ERK(p-ERK) and BCL-2 were down-regulated and P21 up-regulated in RPS27a knockdown cells. In conclusion, RPS27a promotes proliferation, regulates cell cycle progression and inhibits apoptosis of leukemia cells. It appears that drugs targeting RPS27a combining with tyrosine kinase inhibitor (TKI) might represent a novel therapy strategy in TKI resistant CML patients.

  1. Rosiglitazone induces autophagy in H295R and cell cycle deregulation in SW13 adrenocortical cancer cells

    International Nuclear Information System (INIS)

    Cerquetti, Lidia; Sampaoli, Camilla; Amendola, Donatella; Bucci, Barbara; Masuelli, Laura; Marchese, Rodolfo; Misiti, Silvia; De Venanzi, Agostino; Poggi, Maurizio; Toscano, Vincenzo; Stigliano, Antonio

    2011-01-01

    Thiazolidinediones, specific peroxisome proliferator-activated receptor-γ (PPAR-γ) ligands, used in type-2 diabetes therapy, show favourable effects in several cancer cells. In this study we demonstrate that the growth of H295R and SW13 adrenocortical cancer cells is inhibited by rosiglitazone, a thiazolidinediones member, even though the mechanisms underlying this effect appeared to be cell-specific. Treatment with GW9662, a selective PPAR-γ-inhibitor, showed that rosiglitazone acts through both PPAR-γ-dependent and -independent mechanisms in H295R, while in SW13 cells the effect seems to be independent of PPAR-γ. H295R cells treated with rosiglitazone undergo an autophagic process, leading to morphological changes detectable by electron microscopy and an increased expression of specific proteins such as AMPKα and beclin-1. The autophagy seems to be independent of PPAR-γ activation and could be related to an increase in oxidative stress mediated by reactive oxygen species production with the disruption of the mitochondrial membrane potential, triggered by rosiglitazone. In SW13 cells, flow cytometry analysis showed an arrest in the G0/G1 phase of the cell cycle with a decrease of cyclin E and cdk2 activity, following the administration of rosiglitazone. Our data show the potential role of rosiglitazone in the therapeutic approach to adrenocortical carcinoma and indicate the molecular mechanisms at the base of its antiproliferative effects, which appear to be manifold and cell-specific in adrenocortical cancer lines.

  2. Rosiglitazone induces autophagy in H295R and cell cycle deregulation in SW13 adrenocortical cancer cells

    Energy Technology Data Exchange (ETDEWEB)

    Cerquetti, Lidia; Sampaoli, Camilla [Endocrinology, Department of Clinical and Molecular Medicine, Sant' Andrea Hospital, Faculty of Medicine and Psychology ' Sapienza' University of Rome, Via di Grottarossa, 1035-00189 Rome (Italy); Research Center S. Pietro Hospital, Via Cassia, 600-00189 Rome (Italy); Amendola, Donatella; Bucci, Barbara [Research Center S. Pietro Hospital, Via Cassia, 600-00189 Rome (Italy); Masuelli, Laura [Department of Experimental Medicine, ' Sapienza' University of Rome, Rome (Italy); Marchese, Rodolfo [Research Center S. Pietro Hospital, Via Cassia, 600-00189 Rome (Italy); Misiti, Silvia [Endocrinology, Department of Clinical and Molecular Medicine, Sant' Andrea Hospital, Faculty of Medicine and Psychology ' Sapienza' University of Rome, Via di Grottarossa, 1035-00189 Rome (Italy); Research Center S. Pietro Hospital, Via Cassia, 600-00189 Rome (Italy); De Venanzi, Agostino; Poggi, Maurizio; Toscano, Vincenzo [Endocrinology, Department of Clinical and Molecular Medicine, Sant' Andrea Hospital, Faculty of Medicine and Psychology ' Sapienza' University of Rome, Via di Grottarossa, 1035-00189 Rome (Italy); Stigliano, Antonio, E-mail: antonio.stigliano@uniroma1.it [Endocrinology, Department of Clinical and Molecular Medicine, Sant' Andrea Hospital, Faculty of Medicine and Psychology ' Sapienza' University of Rome, Via di Grottarossa, 1035-00189 Rome (Italy); Research Center S. Pietro Hospital, Via Cassia, 600-00189 Rome (Italy)

    2011-06-10

    Thiazolidinediones, specific peroxisome proliferator-activated receptor-{gamma} (PPAR-{gamma}) ligands, used in type-2 diabetes therapy, show favourable effects in several cancer cells. In this study we demonstrate that the growth of H295R and SW13 adrenocortical cancer cells is inhibited by rosiglitazone, a thiazolidinediones member, even though the mechanisms underlying this effect appeared to be cell-specific. Treatment with GW9662, a selective PPAR-{gamma}-inhibitor, showed that rosiglitazone acts through both PPAR-{gamma}-dependent and -independent mechanisms in H295R, while in SW13 cells the effect seems to be independent of PPAR-{gamma}. H295R cells treated with rosiglitazone undergo an autophagic process, leading to morphological changes detectable by electron microscopy and an increased expression of specific proteins such as AMPK{alpha} and beclin-1. The autophagy seems to be independent of PPAR-{gamma} activation and could be related to an increase in oxidative stress mediated by reactive oxygen species production with the disruption of the mitochondrial membrane potential, triggered by rosiglitazone. In SW13 cells, flow cytometry analysis showed an arrest in the G0/G1 phase of the cell cycle with a decrease of cyclin E and cdk2 activity, following the administration of rosiglitazone. Our data show the potential role of rosiglitazone in the therapeutic approach to adrenocortical carcinoma and indicate the molecular mechanisms at the base of its antiproliferative effects, which appear to be manifold and cell-specific in adrenocortical cancer lines.

  3. Driving cycle characterization and generation, for design and control of fuel cell buses

    NARCIS (Netherlands)

    J. Bruinsma; Bram Veenhuizen; P. van den Bosch; Edwin Tazelaar

    2009-01-01

    Optimization routines for battery, supercap and fuel cell stack in a fuel cell based propulsion system face two problems: the tendency to cycle beating and the necessity to maintain identical amounts of stored energy in battery and supercap at the start and end of the driving cycle used in the

  4. Transcription of ribosomal RNA genes is initiated in the third cell cycle of bovine embryos

    DEFF Research Database (Denmark)

    Jakobsen, Anne Sørig; Avery, Birthe; Dieleman, Steph J.

    2006-01-01

    Transcription from the embryos own ribosomal genes is initiated in most species at the same time as the maternal-embryonic transition. Recently data have indicated that a minor activation may take place during the third embryonic cell cycle in the bovine, one cell cycle before the major activatio...

  5. Quantitative Cell Cycle Analysis Based on an Endogenous All-in-One Reporter for Cell Tracking and Classification

    Directory of Open Access Journals (Sweden)

    Thomas Zerjatke

    2017-05-01

    Full Text Available Cell cycle kinetics are crucial to cell fate decisions. Although live imaging has provided extensive insights into this relationship at the single-cell level, the limited number of fluorescent markers that can be used in a single experiment has hindered efforts to link the dynamics of individual proteins responsible for decision making directly to cell cycle progression. Here, we present fluorescently tagged endogenous proliferating cell nuclear antigen (PCNA as an all-in-one cell cycle reporter that allows simultaneous analysis of cell cycle progression, including the transition into quiescence, and the dynamics of individual fate determinants. We also provide an image analysis pipeline for automated segmentation, tracking, and classification of all cell cycle phases. Combining the all-in-one reporter with labeled endogenous cyclin D1 and p21 as prime examples of cell-cycle-regulated fate determinants, we show how cell cycle and quantitative protein dynamics can be simultaneously extracted to gain insights into G1 phase regulation and responses to perturbations.

  6. Prolonged mechanical ventilation induces cell cycle arrest in newborn rat lung.

    Directory of Open Access Journals (Sweden)

    Andreas A Kroon

    Full Text Available RATIONALE: The molecular mechanism(s by which mechanical ventilation disrupts alveolar development, a hallmark of bronchopulmonary dysplasia, is unknown. OBJECTIVE: To determine the effect of 24 h of mechanical ventilation on lung cell cycle regulators, cell proliferation and alveolar formation in newborn rats. METHODS: Seven-day old rats were ventilated with room air for 8, 12 and 24 h using relatively moderate tidal volumes (8.5 mL.kg⁻¹. MEASUREMENT AND MAIN RESULTS: Ventilation for 24 h (h decreased the number of elastin-positive secondary crests and increased the mean linear intercept, indicating arrest of alveolar development. Proliferation (assessed by BrdU incorporation was halved after 12 h of ventilation and completely arrested after 24 h. Cyclin D1 and E1 mRNA and protein levels were decreased after 8-24 h of ventilation, while that of p27(Kip1 was significantly increased. Mechanical ventilation for 24 h also increased levels of p57(Kip2, decreased that of p16(INK4a, while the levels of p21(Waf/Cip1 and p15(INK4b were unchanged. Increased p27(Kip1 expression coincided with reduced phosphorylation of p27(Kip1 at Thr¹⁵⁷, Thr¹⁸⁷ and Thr¹⁹⁸ (p<0.05, thereby promoting its nuclear localization. Similar -but more rapid- changes in cell cycle regulators were noted when 7-day rats were ventilated with high tidal volume (40 mL.kg⁻¹ and when fetal lung epithelial cells were subjected to a continuous (17% elongation cyclic stretch. CONCLUSION: This is the first demonstration that prolonged (24 h of mechanical ventilation causes cell cycle arrest in newborn rat lungs; the arrest occurs in G₁ and is caused by increased expression and nuclear localization of Cdk inhibitor proteins (p27(Kip1, p57(Kip2 from the Kip family.

  7. Cell Cycle Remodeling and Zygotic Gene Activation at the Midblastula Transition.

    Science.gov (United States)

    Zhang, Maomao; Skirkanich, Jennifer; Lampson, Michael A; Klein, Peter S

    2017-01-01

    Following fertilization, vertebrate embryos delay large-scale activation of the zygotic genome from several hours in fish and amphibians to several days in mammals. Externally developing embryos also undergo synchronous and extraordinarily rapid cell divisions that are accelerated by promiscuous licensing of DNA replication origins, absence of gap phases and cell cycle checkpoints, and preloading of the egg with maternal RNAs and proteins needed to drive early development. After a species-specific number of cell divisions, the cell cycle slows and becomes asynchronous, gap phases appear, checkpoint functions are acquired, and large-scale zygotic gene activation begins. These events, along with clearance of maternal RNAs and proteins, define the maternal to zygotic transition and are coordinated at a developmental milestone termed the midblastula transition (MBT). Despite the relative quiescence of the zygotic genome in vertebrate embryos, genes required for clearance of maternal RNAs and for the initial steps in mesoderm induction are robustly transcribed before MBT. The coordination and timing of the MBT depends on a mechanism that senses the ratio of nuclear to cytoplasmic content as well as mechanisms that are independent of the nuclear-cytoplasm ratio. Changes in chromatin architecture anticipate zygotic gene activation, and maternal transcription factors identified as regulators of pluripotency play critical roles in kick-starting the transition from the proliferative, pluripotent state of the early embryo to the more lineage-committed phase of development after the MBT. This chapter describes the regulation of the cell cycle and the activation of zygotic gene expression before and after the MBT in vertebrate embryos.

  8. Transcriptional coregulation by the cell integrity mitogen-activated protein kinase Slt2 and the cell cycle regulator Swi4

    NARCIS (Netherlands)

    Baetz, K; Moffat, J; Haynes, J; Chang, M; Andrews, B

    2001-01-01

    In Saccharomyces cerevis