WorldWideScience

Sample records for cell cycle progression

  1. Cell Cycle Progression of Human Cells Cultured in Rotating Bioreactor

    Science.gov (United States)

    Parks, Kelsey

    2009-01-01

    Space flight has been shown to alter the astronauts immune systems. Because immune performance is complex and reflects the influence of multiple organ systems within the host, scientists sought to understand the potential impact of microgravity alone on the cellular mechanisms critical to immunity. Lymphocytes and their differentiated immature form, lymphoblasts, play an important and integral role in the body's defense system. T cells, one of the three major types of lymphocytes, play a central role in cell-mediated immunity. They can be distinguished from other lymphocyte types, such as B cells and natural killer cells by the presence of a special receptor on their cell surface called T cell receptors. Reported studies have shown that spaceflight can affect the expression of cell surface markers. Cell surface markers play an important role in the ability of cells to interact and to pass signals between different cells of the same phenotype and cells of different phenotypes. Recent evidence suggests that cell-cycle regulators are essential for T-cell function. To trigger an effective immune response, lymphocytes must proliferate. The objective of this project is to investigate the changes in growth of human cells cultured in rotating bioreactors and to measure the growth rate and the cell cycle distribution for different human cell types. Human lymphocytes and lymphoblasts will be cultured in a bioreactor to simulate aspects of microgravity. The bioreactor is a cylindrical culture vessel that incorporates the aspects of clinostatic rotation of a solid fluid body around a horizontal axis at a constant speed, and compensates gravity by rotation and places cells within the fluid body into a sustained free-fall. Cell cycle progression and cell proliferation of the lymphocytes will be measured for a number of days. In addition, RNA from the cells will be isolated for expression of genes related in cell cycle regulations.

  2. Alteration of cell cycle progression by Sindbis virus infection

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    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.

  3. MAPK uncouples cell cycle progression from cell spreading and cytoskeletal organization in cycling cells

    OpenAIRE

    Margadant, Coert; Cremers, Lobke; Sonnenberg, Arnoud; Boonstra, Johannes

    2012-01-01

    Integrin-mediated cytoskeletal tension supports growth-factor-induced proliferation, and disruption of the actin cytoskeleton in growth factor-stimulated cells prevents the re-expression of cyclin D and cell cycle re-entry from quiescence. In contrast to cells that enter the cell cycle from G0, cycling cells continuously express cyclin D, and are subject to major cell shape changes during the cell cycle. Here, we investigated the cell cycle requirements for cytoskeletal tension and cell sprea...

  4. Ionizing radiation and cell cycle progression in ataxia telangiectasia

    International Nuclear Information System (INIS)

    Exposure of mammalian cells to ionizing radiation causes delay in normal progress through the cell cycle at a number of different checkpoints. Abnormalities in these checkpoints have been described for ataxia telangiectasia cells after irradiation. In this report we show that these abnormalities occur at different phases in the cell cycle in several ataxia telangiectasia lymphoblastoid cells. Ataxia telangiectasia cells, synchronized in late G1 phase with either mimosine or aphidicolin and exposed to radiation, showed a reduced delay in entering S phase compared to irradiated control cells. Failure to exhibit G1-phase delay in ataxia telangiectasia cells is accompanied by a reduced ability of radiation to activate the product of the tumor suppressor gene p53, a protein involved in G1/S-phase delay. When the progress of irradiated G1-phase cells was followed into the subsequent G2 and G1 phases ataxia telangiectasia cells showed a more pronounced accumulation in G2 phase than control cells. When cells were irradiated in S phase and extent of delay was more evident in G2 phase and ataxia telangiectasia cells were delayed to a greater extent. These results suggest that the lack of initial delay in both G1 and S phases to the radiosensitivity observed in this syndrome. 26 refs., 3 figs., 2 tabs

  5. Complete and limited proteolysis in cell cycle progression.

    Science.gov (United States)

    Goulet, Brigitte; Nepveu, Alain

    2004-08-01

    An important mechanism of regulation that controls progression through the cell cycle involves the timely degradation of specific regulatory proteins. In parallel to the main degradative pathways, it appears that the function of certain proteins may also be modulated by a process called limited proteolysis. We have recently shown that the CDP/Cux transcription factor is proteolytically processed at the G(1)/S transition by the cathepsin L protease. Two aspects of these findings are discussed in the context of the cell cycle. Firstly, together with the cohesin subunit Scc1 and the HCF-1 factor, CDP/Cux represents a third example whereby the process of "limited proteolysis" plays a role in the control of cell cycle progression. Secondly, our findings provides compelling evidence that the cathepsin L protease, which was believed to be obligatorily targeted through the endoplasmic reticulum to the lysosomes or the extra-cellular milieu, could also be present in the nucleus and modulate the function of transcription factors. PMID:15254406

  6. Soaking RNAi in Bombyx mori BmN4-SID1 cells arrests cell cycle progression.

    Science.gov (United States)

    Mon, Hiroaki; Li, Zhiqing; Kobayashi, Isao; Tomita, Shuichiro; Lee, JaeMan; Sezutsu, Hideki; Tamura, Toshiki; Kusakabe, Takahiro

    2013-01-01

    RNA interference (RNAi) is an evolutionarily conserved mechanism for sequence-specific gene silencing. Previously, the BmN4-SID1 cell expressing Caenorhabditis ele gans SID-1 was established, in which soaking RNAi could induce effective gene silencing. To establish its utility, 6 cell cycle progression related cDNAs, CDK1, MYC, MYB, RNRS, CDT1, and GEMININ, were isolated from the silkworm, Bombyx mori L. (Lepidoptera: Bombycidae), and their expressions were further silenced by soaking RNAi in the BmN4-SID1 cells. The cell cycle progression analysis using flow cytometer demonstrated that the small amount of double stranded RNA was enough to arrest cell cycle progression at the specific cell phases. These data suggest that RNAi in the BmN4-SID1 cells can be used as a powerful tool for loss-of-function analysis of B. mori genes. PMID:24773378

  7. CRL4Cdt2: Master coordinator of cell cycle progression and genome stability

    OpenAIRE

    Abbas, Tarek; Dutta, Anindya

    2011-01-01

    Polyubiquitin-mediated degradation of proteins plays an essential role in various physiological processes including cell cycle progression, transcription and DNA replication and repair. Increasing evidence supports a vital role for the E3 ubiquitin ligase cullin-4, in conjunction with the substrate recognition factor Cdt2 (CRL4Cdt2), for the degradation of multiple cell cycle-regulated proteins to prevent genomic instability. In addition, it is critical for normal cell cycle progression by en...

  8. 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

    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.

  9. Cdk Activity Couples Epigenetic Centromere Inheritance to Cell Cycle Progression

    OpenAIRE

    Silva, Mariana C.C.; Bodor, Dani L.; Stellfox, Madison E.; Martins, Nuno M.C.; Hochegger, Helfrid; Foltz, Daniel R.; Jansen, Lars E.T.

    2012-01-01

    Centromeres form the site of chromosome attachment to microtubules during mitosis. Identity of these loci is maintained epigenetically by nucleosomes containing the histone H3 variant CENP-A. Propagation of CENP-A chromatin is uncoupled from DNA replication initiating only during mitotic exit. We now demonstrate that inhibition of Cdk1 and Cdk2 activities is sufficient to trigger CENP-A assembly throughout the cell cycle in a manner dependent on the canonical CENP-A assembly machinery. We fur...

  10. 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.

  11. 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.

  12. Inhibition of cell cycle progression by penta-acetyl geniposide in rat C6 glioma cells

    International Nuclear Information System (INIS)

    Penta-acetyl geniposide, (Ac)5-GP, the acetylated compound of geniposide, is able to inhibit the growth of rat C6 glioma cells in culture and in the bearing rats. Our recent data indicated that the induction of cell apoptosis and cell cycle arrest at G0/gap phase 1 (G1) by (Ac)5-GP might be associated with the induction of p53 and c-Myc, and mediated via the apoptosis-related bcl-2 family proteins. In this report, we further investigated the mechanism involved in the cell cycle arrest induced by (Ac)5-GP in C6 glioma cells. The inhibitory effect of (Ac)5-GP on the cell cycle progression of C6 glioma cells which arrested cells at the G0/G1 phase was associated with a marked decrease in the protein expression of cyclin D1, and an induction in the content of cyclin-dependent kinase (cdk) inhibitor p21 protein. This effect was correlated with the elevation in p53 levels. Further immunoprecipitation studies found that, in response to the treatment, the formation of cyclin D1/cdk 4 complex declined, preventing the phosphorylation of retinoblastoma (Rb) and the subsequent dissociation of Rb/E2F complex. These results illustrated that the apoptotic effect of (Ac)5-GP, arresting cells at the G0/G1 phase, was exerted by inducing the expression of p21 that, in turn, repressed the activity of cyclin D1/cdk 4 and the phosphorylation of Rb

  13. WNT5A modulates cell cycle progression and contributes to the chemoresistance in pancreatic cancer cells

    Institute of Scientific and Technical Information of China (English)

    Wei Wei; Hui-Hui Sun; Na Li; Hong-Yue Li; Xin Li; Qiang Li; Xiao-Hong Shen

    2014-01-01

    BACKGROUND: Although there are many studies on the mechanism of chemoresistance in cancers, studies on the relations between WNT5A and chemoresistance in pancreatic cancer are rare. The present study was to examine the role of WNT5A in the regulation of cell cycle progression and in chemoresistance in pancreatic cancer tissues and cell lines. METHODS: Fresh pancreatic cancer and paracarcinoma tissues were obtained from 32 patients. The expressions of WNT5A, AKT/p-AKT and Cyclin D1 were detected by immunohistochemistry, and the correlation between WNT5A expression and clinicopathological characteristics was analyzed. The relationship between WNT5A expression and gemcitabine resistance was studied in PANC-1 and MIAPaCa2 cell lines. The effect of WNT5A on the regulation of cell cycle and gemcitabine cytotoxicity were investigated. The associations among the expressions of p-AKT, Cyclin D1 and WNT5A were also analyzed in cell lines and the effect of WNT5A on restriction-point (R-point) progression was evaluated. RESULTS: WNT5A, p-AKT and Cyclin D1 were highly expressed in pancreatic cancer tissues, and the WNT5A expression was correlated with the TNM stages. In vitro, WNT5A expression was associated with gemcitabine chemoresistance. The percentage of cells was increased in G0/G1 phase and decreased in S phase after knockdown of WNT5A in PANC-1. WNT5A promoted Cyclin D1 expression through phosphorylation of AKT which consequently enhanced G1-S transition and gemcitabine resistance. Furthermore, WNT5A enhanced the cell cycle progression toward R-point through regulation of retinoblastoma protein (pRb) and pRb-E2F complex formation. CONCLUSIONS: WNT5A induced chemoresistance by regulation of G1-S transition in pancreatic cancer cells. WNT5A might serve as a predictor of gemcitabine response and as a potential target for tumor chemotherapy.

  14. Mitochondrial regulation of cell cycle progression through SLC25A43.

    Science.gov (United States)

    Gabrielson, Marike; Reizer, Edwin; Stål, Olle; Tina, Elisabet

    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 G1-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 G1-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. PMID:26721434

  15. Effects of 60Co γ rays on the cell cycle progress of MCF-7 cells

    International Nuclear Information System (INIS)

    To investigate the effects of ionizing radiation on cell cycle progress of tumor cell lines, the human breast cancer MCF-7 cell line cultured in vitro was exposed to 60Co γ rays and the alterations in cell cycle progress after irradiation were measured by flow cytometry. The results indicated that the MCF-7 cells showed a transient S arrest continuing for about 6 h and an obvious G2 arrest continuing for about 63 h after irradiation with 5.0 Gy γ rays. S and G2 arrest culminated at 9 h and 18 h respectively after irradiation and the peak values of S and G2 arrest reached respectively 1.6 times and 6.2 times as many as normal value. The dose-effect curve examined 9 h after irradiation was quite different from that examined 18 h after irradiation. Both of the S arrest at 9 h after irradiation and the G2 arrest at 18 h after irradiation presented significant relationship with irradiation dose

  16. Morphogenesis checkpoint kinase Swe1 is the executor of lipolysis-dependent cell-cycle progression.

    Science.gov (United States)

    Chauhan, Neha; Visram, Myriam; Cristobal-Sarramian, Alvaro; Sarkleti, Florian; Kohlwein, Sepp D

    2015-03-10

    Cell growth and division requires the precise duplication of cellular DNA content but also of membranes and organelles. Knowledge about the cell-cycle-dependent regulation of membrane and storage lipid homeostasis is only rudimentary. Previous work from our laboratory has shown that the breakdown of triacylglycerols (TGs) is regulated in a cell-cycle-dependent manner, by activation of the Tgl4 lipase by the major cyclin-dependent kinase Cdc28. The lipases Tgl3 and Tgl4 are required for efficient cell-cycle progression during the G1/S (Gap1/replication phase) transition, at the onset of bud formation, and their absence leads to a cell-cycle delay. We now show that defective lipolysis activates the Swe1 morphogenesis checkpoint kinase that halts cell-cycle progression by phosphorylation of Cdc28 at tyrosine residue 19. Saturated long-chain fatty acids and phytosphingosine supplementation rescue the cell-cycle delay in the Tgl3/Tgl4 lipase-deficient strain, suggesting that Swe1 activity responds to imbalanced sphingolipid metabolism, in the absence of TG degradation. We propose a model by which TG-derived sphingolipids are required to activate the protein phosphatase 2A (PP2A(Cdc55)) to attenuate Swe1 phosphorylation and its inhibitory effect on Cdc28 at the G1/S transition of the cell cycle. PMID:25713391

  17. The Giardia cell cycle progresses independently of the anaphase-promoting complex

    OpenAIRE

    Gourguechon, Stéphane; Holt, Liam J.; Cande, W. Zacheus

    2013-01-01

    Most cell cycle regulation research has been conducted in model organisms representing a very small part of the eukaryotic domain. The highly divergent human pathogen Giardia intestinalis is ideal for studying the conservation of eukaryotic pathways. Although Giardia has many cell cycle regulatory components, its genome lacks all anaphase-promoting complex (APC) components. In the present study, we show that a single mitotic cyclin in Giardia is essential for progression into mitosis. Strikin...

  18. Requirement for TAFII250 Acetyltransferase Activity in Cell Cycle Progression

    OpenAIRE

    Dunphy, Elizabeth L.; Johnson, Theron; Auerbach, Scott s.; Wang, Edith H.

    2000-01-01

    The TATA-binding protein (TBP)-associated factor TAFII250 is the largest component of the basal transcription factor IID (TFIID). A missense mutation that maps to the acetyltransferase domain of TAFII250 induces the temperature-sensitive (ts) mutant hamster cell lines ts13 and tsBN462 to arrest in late G1. At the nonpermissive temperature (39.5°C), transcription from only a subset of protein encoding genes, including the G1 cyclins, is dramatically reduced in the mutant cells. Here we demonst...

  19. 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.

  20. Inhibitor of DNA binding 1 regulates cell cycle progression of endothelial progenitor cells through induction of Wnt2 expression.

    Science.gov (United States)

    Xia, Xi; Yu, Yang; Zhang, Li; Ma, Yang; Wang, Hong

    2016-09-01

    Endothelial injury is a risk factor for atherosclerosis. Endothelial progenitor cell (EPC) proliferation contributes to vascular injury repair. Overexpression of inhibitor of DNA binding 1 (Id1) significantly promotes EPC proliferation; however, the underlying molecular mechanism remains to be fully elucidated. The present study investigated the role of Id1 in cell cycle regulation of EPCs, which is closely associated with proliferation. Overexpression of Id1 increased the proportion of EPCs in the S/G2M phase and significantly increased cyclin D1 expression levels, while knockdown of Id1 arrested the cell cycle progression of EPCs in the G1 phase and inhibited cyclin D1 expression levels. In addition, it was demonstrated that Id1 upregulated wingless‑type mouse mammary tumor virus integration site family member 2 (Wnt2) expression levels and promoted β‑catenin accumulation and nuclear translocation. Furthermore, Wnt2 knockdown counteracted the effects of Id1 on cell cycle progression of EPCs. In conclusion, the results of the present study indicate that Id1 promoted Wnt2 expression, which accelerated cell cycle progression from G1 to S phase. This suggests that Id1 may promote cell cycle progression of EPCs, and that Wnt2 may be important in Id1 regulation of the cell cycle of EPCs. PMID:27432753

  1. Enforcing temporal control of maternal mRNA translation during oocyte cell-cycle progression

    OpenAIRE

    Arumugam, Karthik; Wang, Yiying; Hardy, Linda L.; MacNicol, Melanie C.; MacNicol, Angus M

    2009-01-01

    Meiotic cell-cycle progression in progesterone-stimulated Xenopus oocytes requires that the translation of pre-existing maternal mRNAs occur in a strict temporal order. Timing of translation is regulated through elements within the mRNA 3′ untranslated region (3′ UTR), which respond to cell cycle-dependant signalling. One element that has been previously implicated in the temporal control of mRNA translation is the cytoplasmic polyadenylation element (CPE). In this study, we show that the CPE...

  2. CDK2-dependent phosphorylation of Suv39H1 is involved in control of heterochromatin replication during cell cycle progression

    OpenAIRE

    Park, Su Hyung; Yu, Seung Eun; Chai, Young Gyu; Jang, Yeun Kyu

    2014-01-01

    Although several studies have suggested that the functions of heterochromatin regulators may be regulated by post-translational modifications during cell cycle progression, regulation of the histone methyltransferase Suv39H1 is not fully understood. Here, we demonstrate a direct link between Suv39H1 phosphorylation and cell cycle progression. We show that CDK2 phosphorylates Suv39H1 at Ser391 and these phosphorylation levels oscillate during the cell cycle, peaking at S phase and maintained d...

  3. Nuclear translocation of hARD1 contributes to proper cell cycle progression.

    Directory of Open Access Journals (Sweden)

    Ji-Hyeon Park

    Full Text Available Arrest defective 1 (ARD1 is an acetyltransferase that is highly conserved across organisms, from yeasts to humans. The high homology and widespread expression of ARD1 across multiple species and tissues signify that it serves a fundamental role in cells. Human ARD1 (hARD1 has been suggested to be involved in diverse biological processes, and its role in cell proliferation and cancer development has been recently drawing attention. However, the subcellular localization of ARD1 and its relevance to cellular function remain largely unknown. Here, we have demonstrated that hARD1 is imported to the nuclei of proliferating cells, especially during S phase. Nuclear localization signal (NLS-deleted hARD1 (hARD1ΔN, which can no longer access the nucleus, resulted in cell morphology changes and cellular growth impairment. Notably, hARD1ΔN-expressing cells showed alterations in the cell cycle and the expression levels of cell cycle regulators compared to hARD1 wild-type cells. Furthermore, these effects were rescued when the nuclear import of hARD1 was restored by exogenous NLS. Our results show that hARD1 nuclear translocation mediated by NLS is required for cell cycle progression, thereby contributing to proper cell proliferation.

  4. DREF Is Required for Efficient Growth and Cell Cycle Progression in Drosophila Imaginal Discs

    OpenAIRE

    Hyun, Joogyung; Jasper, Heinrich; Bohmann, Dirk

    2005-01-01

    Based on overexpression studies and target gene analyses, the transcription factor DNA replication-related element factor (DREF) has been proposed to regulate growth and replication in Drosophila melanogaster. Here we present loss-of-function experiments to analyze the contribution of DREF to these processes. RNA interference-mediated extinction of DREF function in vivo demonstrates a requirement for the protein for normal progression through the cell cycle and consequently for growth of imag...

  5. An Emerging Model for BAP1’s Role in Regulating Cell Cycle Progression

    OpenAIRE

    Eletr, Ziad M.; Wilkinson, Keith D.

    2011-01-01

    BRCA1-associated protein-1 (BAP1) is a 729 residue, nuclear-localized deubiquitinating enzyme (DUB) that displays tumor suppressor properties in the BAP1-null NCI-H226 lung carcinoma cell line. Studies that have altered BAP1 cellular levels or enzymatic activity have reported defects in cell cycle progression, notably at the G1/S transition. Recently BAP1 was shown to associate with the transcriptional regulator host cell factor 1 (HCF-1). The BAP1/HCF-1 interaction is mediated by the HCF-1 K...

  6. Methamphetamine alters the normal progression by inducing cell cycle arrest in astrocytes.

    Directory of Open Access Journals (Sweden)

    Austin R Jackson

    Full Text Available Methamphetamine (MA is a potent psychostimulant with a high addictive capacity, which induces many deleterious effects on the brain. Chronic MA abuse leads to cognitive dysfunction and motor impairment. MA affects many cells in the brain, but the effects on astrocytes of repeated MA exposure is not well understood. In this report, we used Gene chip array to analyze the changes in the gene expression profile of primary human astrocytes treated with MA for 3 days. Range of genes were found to be differentially regulated, with a large number of genes significantly downregulated, including NEK2, TTK, TOP2A, and CCNE2. Gene ontology and pathway analysis showed a highly significant clustering of genes involved in cell cycle progression and DNA replication. Further pathway analysis showed that the genes downregulated by multiple MA treatment were critical for G2/M phase progression and G1/S transition. Cell cycle analysis of SVG astrocytes showed a significant reduction in the percentage of cell in the G2/M phase with a concomitant increase in G1 percentage. This was consistent with the gene array and validation data, which showed that repeated MA treatment downregulated the genes associated with cell cycle regulation. This is a novel finding, which explains the effect of MA treatment on astrocytes and has clear implication in neuroinflammation among the drug abusers.

  7. Control of the cell cycle progression by the MAPK Hog1

    Directory of Open Access Journals (Sweden)

    Josep Clotet

    2013-02-01

    Full Text Available Eukaryotic cells coordinate various intracellular activities in response to environmental stresses, activating an adaptive program to maximize the probability of survival and proliferation. Cells transduce diverse cellular stimuli by multiple mitogen-activated protein kinase (MAPK cascades. MAPK are key signal transduction kinases required to respond to stress. A prototypical member of the MAPK family is the yeast high osmolarity glycerol (Hog1. Activation of Hog1 results in the generation of a set of adaptive responses that leads to the modulation of several aspects of cell physiology that are essential for cell survival, such as gene expression, translation, and morphogenesis. This review focuses on the control of cell cycle progression by Hog1 which is critical for cell survival in response to stress conditions.

  8. An emerging model for BAP1's role in regulating cell cycle progression.

    Science.gov (United States)

    Eletr, Ziad M; Wilkinson, Keith D

    2011-06-01

    BRCA1-associated protein-1 (BAP1) is a 729 residue, nuclear-localized deubiquitinating enzyme (DUB) that displays tumor suppressor properties in the BAP1-null NCI-H226 lung carcinoma cell line. Studies that have altered BAP1 cellular levels or enzymatic activity have reported defects in cell cycle progression, notably at the G1/S transition. Recently BAP1 was shown to associate with the transcriptional regulator host cell factor 1 (HCF-1). The BAP1/HCF-1 interaction is mediated by the HCF-1 Kelch domain and an HCF-1 binding motif (HBM) within BAP1. HCF-1 is modified with ubiquitin in vivo, and ectopic studies suggest BAP1 deubiquitinates HCF-1. HCF-1 is a chromatin-associated protein thought to both activate and repress transcription by linking appropriate histone-modifying enzymes to a subset of transcription factors. One known role of HCF-1 is to promote cell cycle progression at the G1/S boundary by recruiting H3K4 histone methyltransferases to the E2F1 transcription factor so that genes required for S-phase can be transcribed. Given the robust associations between BAP1/HCF-1 and HCF-1/E2Fs, it is reasonable to speculate that BAP1 influences cell proliferation at G1/S by co-regulating transcription from HCF-1/E2F-governed promoters. PMID:21484256

  9. 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

  10. Inhibitory Effects of Berberine on the Activation and Cell Cycle Progression of Human Peripheral Lymphocytes

    Institute of Scientific and Technical Information of China (English)

    Lihui Xu; Yi Liu; Xianhui He

    2005-01-01

    The immunosuppressive property of berberine, an isoquinoline alkaloid, has been well documented, but the mechanism of its action on lymphocytes has not been completely elucidated. The present study is to investigate the effect of berberine on the activation and proliferation of lymphocytes, in particular T lymphocytes. Whole peripheral blood from healthy donors was stimulated with phytohemagglutinin (PHA) alone or phorbol dibutyrate (PDB) plus ionomycin, and the expression of CD69 and CD25 on T lymphocytes was evaluated with flow cytometry.The distribution of cell cycles and cell viability were analyzed by staining with propidium iodide (PI) and 7-aminoactinomycin D (7-AAD), respectively. The results showed that 100 μmol/L and 50 μmol/L of berberine significantly inhibited CD69 expression on T cells stimulated with PDB plus ionomycin or PHA, whereas the effect of 25 μmol/L berberine was not significant. As the incubation time increased, the extent of inhibition decreased.Similarly, the expression of CD25 was also reduced by berberine in a dose-dependent manner over the concentration range of 25-100 μmol/L. Besides, this alkaloid could block lymphocyte cell cycle progression from G0/G1 phase to S and G2/M phase without phase specificity. Moreover, analysis following 7-AAD staining revealed that berberine had no significant cytotoxicity on lymphocytes. Taken together, berberine significantly inhibits the expression of activation antigens on T lymphocytes and also blocks the progression of cell cycles of lymphocytes,suggesting that berberine may exert immunosuppressive effect through inhibiting the activation and proliferation of T cells.

  11. Bioenergetic coupling between membrane transport systems and biosynthetic pathways essential for cell cycle progression

    International Nuclear Information System (INIS)

    Recently, it has been shown that there exists a point in the cell cycle (approximately 2 h prior to S phase entry) when (Na+/K+)ATPase pump activity is no longer needed for progression through the cycle. These data suggests that pump activity is critical in the biosynthetic processes which enables the cell to proceed through the G1 phase. A scheme is proposed which is currently being tested that (Na+/K+)ATPase pump activity serves as the driving force in the regulation of other membrane transport processes critical for cell proliferation. For example, in post-confluent quiescent C3H-10T1/2 fibroblasts, when [K+]/sub o/ is lowered just below the K/sub m/ of the pump for K+ there is a 10-fold increase in 3H-uridine uptake into both acid soluble and insoluble cell fractions. By modulation of the pump in this manner, glucose utilization is enhanced whereas inhibition of the pump by ouabain suppresses glucose utilization. In both methods of affecting the pump, 3H-leucine incorporation is inhibited. Electron acceptors that influence the redox state of the cell have been shown to both stimulate or inhibit cell cycle progression. Under conditions where [K+]/sub o/ is lowered, the nucleoside uptake responses observed were modified by electron acceptors depending on the ability to oxidize NAD(P)H directly or to interact with a cytochrome-like component, (e.g. phenazine methosulfate) reversed the enhanced uridine uptake and p-phenylene diamine further enhanced the uridine uptake response. These findings suggest that a plasma membrane redox system (presumably cyt-c like) is linked to nucleoside transport which is subject to (Na+/K+)ATPase activity

  12. Progestins reinitiate cell cycle progression in antiestrogen-arrested breast cancer cells through the B-isoform of progesterone receptor.

    Science.gov (United States)

    McGowan, Eileen M; Russell, Amanda J; Boonyaratanakornkit, Viroj; Saunders, Darren N; Lehrbach, Gillian M; Sergio, C Marcelo; Musgrove, Elizabeth A; Edwards, Dean P; Sutherland, Robert L

    2007-09-15

    Estrogen treatment of MCF-7 human breast cancer cells allows the reinitiation of synchronous cell cycle progression in antiestrogen-arrested cells. Here, we report that progestins also reinitiate cell cycle progression in this model. Using clonal cell lines derived from progesterone receptor (PR)-negative MCF-7M13 cells expressing wild-type or mutant forms of PRA and PRB, we show that this effect is mediated via PRB, not PRA. Cell cycle progression did not occur with a DNA-binding domain mutant of PRB but was unaffected by mutation in the NH(2)-terminal, SH3 domain interaction motif, which mediates rapid progestin activation of c-Src. Thus, the progestin-induced proliferative response in antiestrogen-inhibited cells is mediated primarily by the transcriptional activity of PRB. Analysis of selected cell cycle targets showed that progestin treatment induced levels of cyclin D1 expression and retinoblastoma protein (Rb) phosphorylation similar to those induced by estradiol. In contrast, progestin treatment resulted in only a 1.2-fold induction of c-Myc compared with a 10-fold induction by estradiol. These results support the conclusion that progestin, in a PRB-dependent manner, can overcome the growth-inhibitory effects of antiestrogens in estrogen receptor/PR-positive breast cancer cells by the induction of cyclin D1 expression. The mediation of this effect by PRB, but not PRA, further suggests a mechanism whereby abnormal regulation of the normal expression ratios of PR isoforms in breast cancer could lead to the attenuation of antiestrogen-mediated growth arrest. PMID:17875737

  13. A systems biology dynamical model of mammalian G1 cell cycle progression

    OpenAIRE

    Haberichter, Thomas; Mädge, Britta; Christopher, Renee A; Yoshioka, Naohisa; Dhiman, Anjali; Miller, Robert; Gendelman, Rina; Aksenov, Sergej V.; Khalil, Iya G; Dowdy, Steven F.

    2007-01-01

    The current dogma of G1 cell-cycle progression relies on growth factor-induced increase of cyclin D:Cdk4/6 complex activity to partially inactivate pRb by phosphorylation and to sequester p27Kip1-triggering activation of cyclin E:Cdk2 complexes that further inactivate pRb. pRb oscillates between an active, hypophosphorylated form associated with E2F transcription factors in early G1 phase and an inactive, hyperphosphorylated form in late G1, S and G2/M phases. However, under constant growth f...

  14. Role of insulin-like growth factor-1 (IGF-1) in regulating cell cycle progression

    Energy Technology Data Exchange (ETDEWEB)

    Ma, Qi-lin; Yang, Tian-lun [Department of Cardiology, Xiangya Hospital, Central South University, Changsha 410008, Hunan (China); Yin, Ji-ye [Institute of Clinical Pharmacology, Hunan Key Laboratory of Pharmacogenetics, Xiangya School of Medicine, Central South University, Changsha 410078, Hunan (China); Peng, Zhen-yu [Department of Cardiology, Xiangya Hospital, Central South University, Changsha 410008, Hunan (China); Yu, Min [Institute of Clinical Pharmacology, Hunan Key Laboratory of Pharmacogenetics, Xiangya School of Medicine, Central South University, Changsha 410078, Hunan (China); Liu, Zhao-qian, E-mail: liuzhaoqian63@126.com [Institute of Clinical Pharmacology, Hunan Key Laboratory of Pharmacogenetics, Xiangya School of Medicine, Central South University, Changsha 410078, Hunan (China); Chen, Fang-ping, E-mail: xychenfp@public.cs.hn.Cn [Department of Haematology, Xiangya Hospital, Central South University, Changsha 410008, Hunan (China)

    2009-11-06

    Aims: Insulin-like growth factor-1 (IGF-1) is a polypeptide protein hormone, similar in molecular structure to insulin, which plays an important role in cell migration, cell cycle progression, cell survival and proliferation. In this study, we investigated the possible mechanisms of IGF-1 mediated cell cycle redistribution and apoptosis of vascular endothelial cells. Method: Human umbilical vein endothelial cells (HUVECs) were pretreated with 0.1, 0.5, or 2.5 {mu}g/mL of IGF-1 for 30 min before the addition of Ang II. Cell cycle redistribution and apoptosis were examined by flow cytometry. Expression of Ang II type 1 (AT{sub 1}) mRNA and cyclin E protein were determined by RT-PCR and Western blot, respectively. Results: Ang II (1 {mu}mol/L) induced HUVECs arrested at G{sub 0}/G{sub 1}, enhanced the expression level of AT{sub 1} mRNA in a time-dependent manner, reduced the enzymatic activity of nitric oxide synthase (NOS) and nitric oxide (NO) content as well as the expression level of cyclin E protein. However, IGF-1 enhanced NOS activity, NO content, and the expression level of cyclin E protein, and reduced the expression level of AT{sub 1} mRNA. L-NAME significantly counteracted these effects of IGF-1. Conclusions: Our data suggests that IGF-1 can reverse vascular endothelial cells arrested at G{sub 0}/G{sub 1} and apoptosis induced by Ang II, which might be mediated via a NOS-NO signaling pathway and is likely associated with the expression levels of AT1 mRNA and cyclin E proteins.

  15. Roles for the Histone Modifying and Exchange Complex NuA4 in Cell Cycle Progression in Drosophila melanogaster.

    Science.gov (United States)

    Flegel, Kerry; Grushko, Olga; Bolin, Kelsey; Griggs, Ellen; Buttitta, Laura

    2016-07-01

    Robust and synchronous repression of E2F-dependent gene expression is critical to the proper timing of cell cycle exit when cells transition to a postmitotic state. Previously NuA4 was suggested to act as a barrier to proliferation in Drosophila by repressing E2F-dependent gene expression. Here we show that NuA4 activity is required for proper cell cycle exit and the repression of cell cycle genes during the transition to a postmitotic state in vivo However, the delay of cell cycle exit caused by compromising NuA4 is not due to additional proliferation or effects on E2F activity. Instead NuA4 inhibition results in slowed cell cycle progression through late S and G2 phases due to aberrant activation of an intrinsic p53-independent DNA damage response. A reduction in NuA4 function ultimately produces a paradoxical cell cycle gene expression program, where certain cell cycle genes become derepressed in cells that are delayed during the G2 phase of the final cell cycle. Bypassing the G2 delay when NuA4 is inhibited leads to abnormal mitoses and results in severe tissue defects. NuA4 physically and genetically interacts with components of the E2F complex termed D: rosophila, R: bf, E: 2F A: nd M: yb/ M: ulti-vulva class B: (DREAM/MMB), and modulates a DREAM/MMB-dependent ectopic neuron phenotype in the posterior wing margin. However, this effect is also likely due to the cell cycle delay, as simply reducing Cdk1 is sufficient to generate a similar phenotype. Our work reveals that the major requirement for NuA4 in the cell cycle in vivo is to suppress an endogenous DNA damage response, which is required to coordinate proper S and G2 cell cycle progression with differentiation and cell cycle gene expression. PMID:27184390

  16. Regulation of KAT6 Acetyltransferases and Their Roles in Cell Cycle Progression, Stem Cell Maintenance, and Human Disease.

    Science.gov (United States)

    Huang, Fu; Abmayr, Susan M; Workman, Jerry L

    2016-07-15

    The lysine acetyltransferase 6 (KAT6) histone acetyltransferase (HAT) complexes are highly conserved from yeast to higher organisms. They acetylate histone H3 and other nonhistone substrates and are involved in cell cycle regulation and stem cell maintenance. In addition, the human KAT6 HATs are recurrently mutated in leukemia and solid tumors. Therefore, it is important to understand the mechanisms underlying the regulation of KAT6 HATs and their roles in cell cycle progression. In this minireview, we summarize the identification and analysis of the KAT6 complexes and discuss the regulatory mechanisms governing their enzymatic activities and substrate specificities. We further focus on the roles of KAT6 HATs in regulating cell proliferation and stem cell maintenance and review recent insights that aid in understanding their involvement in human diseases. PMID:27185879

  17. Delay of cell cycle progression after X-irradiation of synchronized populations of human cells (NHIK 3025) in culture

    International Nuclear Information System (INIS)

    The effect of X-irradiation on the cell cycle progression of synchronized populations of the human cell line NHIK 3035 has been studied in terms of the radiation-induced delay of DNA replication and cell division. Results were obtained by flow cytometric measurements of histograms of cellular DNA content and parallel use of conventional methods for cell cycle analysis, such as pulse labelling with (3H) thymidine and counting of cell numbers. The two sets of methods were generally in good agreement, but the advantages of employing two independent techniques are pointed out. Irradiation was found to have a minor influence on DNA replication. As compared with unirradiated populations, half-completed DNA replication was 20-30 min delayed in populations given 580 rad in mid-G1 or 290 rad in early S. Cell cycle progression was markedly delayed in G2. The sensitivity induction of this delay was 0.6 min/rad for populations irradiated in mid-G1, and 1.4 min/rad for populations irradiated in early S. (author)

  18. A human BRCA2 complex containing a structural DNA binding component influences cell cycle progression.

    Science.gov (United States)

    Marmorstein, L Y; Kinev, A V; Chan, G K; Bochar, D A; Beniya, H; Epstein, J A; Yen, T J; Shiekhattar, R

    2001-01-26

    Germline mutations of the human BRCA2 gene confer susceptibility to breast cancer. Although the function of the BRCA2 protein remains to be determined, murine cells homozygous for BRCA2 inactivation display chromosomal aberrations. We have isolated a 2 MDa BRCA2-containing complex and identified a structural DNA binding component, designated as BRCA2-Associated Factor 35 (BRAF35). BRAF35 contains a nonspecific DNA binding HMG domain and a kinesin-like coiled coil domain. Similar to BRCA2, BRAF35 mRNA expression levels in mouse embryos are highest in proliferating tissues with high mitotic index. Strikingly, nuclear staining revealed a close association of BRAF35/BRCA2 complex with condensed chromatin coincident with histone H3 phosphorylation. Importantly, antibody microinjection experiments suggest a role for BRCA2/BRAF35 complex in modulation of cell cycle progression. PMID:11207365

  19. Interplay of posttranslational modifications in Sp1 mediates Sp1 stability during cell cycle progression.

    Science.gov (United States)

    Wang, Yi-Ting; Yang, Wen-Bin; Chang, Wen-Chang; Hung, Jan-Jong

    2011-11-18

    Although Sp1 is known to undergo posttranslational modifications such as phosphorylation, glycosylation, acetylation, sumoylation, and ubiquitination, little is known about the possible interplay between the different forms of Sp1 that may affect its overall levels. It is also unknown whether changes in the levels of Sp1 influence any biological cell processes. Here, we identified RNF4 as the ubiquitin E3 ligase of Sp1. From in vitro and in vivo experiments, we found that sumoylated Sp1 can recruit RNF4 as a ubiquitin E3 ligase that subjects sumoylated Sp1 to proteasomal degradation. Sp1 mapping revealed two ubiquitination-related domains: a small ubiquitin-like modifier in the N-terminus of Sp1(Lys16) and the C-terminus of Sp1 that directly interacts with RNF4. Interestingly, when Sp1 was phosphorylated at Thr739 by c-Jun NH(2)-terminal kinase 1 during mitosis, this phosphorylated form of Sp1 abolished the Sp1-RNF4 interaction. Our results show that, while sumoylated Sp1 subjects to proteasomal degradation, the phosphorylation that occurs during the cell cycle can protect Sp1 from degradation by repressing the Sp1-RNF4 interaction. Thus, we propose that the interplay between posttranslational modifications of Sp1 plays an important role in cell cycle progression and keeps Sp1 at a critical level for mitosis. PMID:21983342

  20. The Yeast Cyclin-Dependent Kinase Routes Carbon Fluxes to Fuel Cell Cycle Progression.

    Science.gov (United States)

    Ewald, Jennifer C; Kuehne, Andreas; Zamboni, Nicola; Skotheim, Jan M

    2016-05-19

    Cell division entails a sequence of processes whose specific demands for biosynthetic precursors and energy place dynamic requirements on metabolism. However, little is known about how metabolic fluxes are coordinated with the cell division cycle. Here, we examine budding yeast to show that more than half of all measured metabolites change significantly through the cell division cycle. Cell cycle-dependent changes in central carbon metabolism are controlled by the cyclin-dependent kinase (Cdk1), a major cell cycle regulator, and the metabolic regulator protein kinase A. At the G1/S transition, Cdk1 phosphorylates and activates the enzyme Nth1, which funnels the storage carbohydrate trehalose into central carbon metabolism. Trehalose utilization fuels anabolic processes required to reliably complete cell division. Thus, the cell cycle entrains carbon metabolism to fuel biosynthesis. Because the oscillation of Cdk activity is a conserved feature of the eukaryotic cell cycle, we anticipate its frequent use in dynamically regulating metabolism for efficient proliferation. PMID:27203178

  1. Uncovering SUMOylation Dynamics during Cell-Cycle Progression Reveals FoxM1 as a Key Mitotic SUMO Target Protein

    DEFF Research Database (Denmark)

    Schimmel, Joost; Eifler, Karolin; Sigurdsson, Jón Otti; Cuijpers, Sabine A G; Hendriks, Ivo A; Verlaan-de Vries, Matty; Kelstrup, Christian D; Francavilla, Chiara; Medema, René H; Olsen, Jesper Velgaard; Vertegaal, Alfred C O

    2014-01-01

    Loss of small ubiquitin-like modification (SUMOylation) in mice causes genomic instability due to the missegregation of chromosomes. Currently, little is known about the identity of relevant SUMO target proteins that are involved in this process and about global SUMOylation dynamics during cell-cycle...... progression. We performed a large-scale quantitative proteomics screen to address this and identified 593 proteins to be SUMO-2 modified, including the Forkhead box transcription factor M1 (FoxM1), a key regulator of cell-cycle progression and chromosome segregation. SUMOylation of FoxM1 peaks during G2 and M...... relieving FoxM1 autorepression. Cells deficient for FoxM1 SUMOylation showed increased levels of polyploidy. Our findings contribute to understanding the role of SUMOylation during cell-cycle progression....

  2. The regulatory beta-subunit of protein kinase CK2 regulates cell-cycle progression at the onset of mitosis

    DEFF Research Database (Denmark)

    Yde, C W; Olsen, B B; Meek, D;

    2008-01-01

    Cell-cycle transition from the G(2) phase into mitosis is regulated by the cyclin-dependent protein kinase 1 (CDK1) in complex with cyclin B. CDK1 activity is controlled by both inhibitory phosphorylation, catalysed by the Myt1 and Wee1 kinases, and activating dephosphorylation, mediated by the CDC...... interference results in delayed cell-cycle progression at the onset of mitosis. Knockdown of CK2beta causes stabilization of Wee1 and increased phosphorylation of CDK1 at the inhibitory Tyr15. PLK1-Wee1 association is an essential event in the degradation of Wee1 in unperturbed cell cycle. We have found that...... regulatory subunit, identifying it as a new component of signaling pathways that regulate cell-cycle progression at the entry of mitosis.Oncogene advance online publication, 12 May 2008; doi:10.1038/onc.2008.146....

  3. Salicylic acid antagonizes abscisic acid inhibition of shoot growth and cell cycle progression in rice

    Science.gov (United States)

    Meguro, Ayano; Sato, Yutaka

    2014-04-01

    We analysed effects of abscisic acid (ABA, a negative regulatory hormone), alone and in combination with positive or neutral hormones, including salicylic acid (SA), on rice growth and expression of cell cycle-related genes. ABA significantly inhibited shoot growth and induced expression of OsKRP4, OsKRP5, and OsKRP6. A yeast two-hybrid assay showed that OsKRP4, OsKRP5, and OsKRP6 interacted with OsCDKA;1 and/or OsCDKA;2. When SA was simultaneously supplied with ABA, the antagonistic effect of SA completely blocked ABA inhibition. SA also blocked ABA inhibition of DNA replication and thymidine incorporation in the shoot apical meristem. These results suggest that ABA arrests cell cycle progression by inducing expression of OsKRP4, OsKRP5, and OsKRP6, which inhibit the G1/S transition, and that SA antagonizes ABA by blocking expression of OsKRP genes.

  4. Prevention of Simvastatin-Induced Inhibition of Tendon Cell Proliferation and Cell Cycle Progression by Geranylgeranyl Pyrophosphate.

    Science.gov (United States)

    Tsai, Wen-Chung; Yu, Tung-Yang; Lin, Li-Ping; Cheng, Mei-Ling; Chen, Cheng-Lun; Pang, Jong-Hwei S

    2016-02-01

    Statins have been reported to induce tendinopathy and even tendon rupture. The present study was designed to investigate the potential molecular mechanism underlying the adverse effect of simvastatin on tendon cells. An in vitro tendon healing model was performed using tendon cells isolated from rat Achilles tendons. The viability of tendon cells and cell cycle progression were examined by the MTT assay and flow cytometric analysis, respectively. Immunofluorescent staining for Ki-67 was used to assess the proliferation activity of tendon cells. Western blot analysis and coimmunoprecipitation was used to determine the protein expression of cell cycle-related proteins. To investigate the potential mechanism underlying the effect of statins on tendon cells, mevalonate, farnesyl pyrophosphate (FPP), or geranylgeranyl pyrophosphate (GGPP) was added to simvastatin-treated tendon cells. Simvastatin inhibited the in vitro tendon healing model and tendon cell proliferation in a dose-dependent manner. Immunofluorescent staining demonstrated reduced ki-67 expression in simvastatin-treated tendon cells. Furthermore, simvastatin induced cell cycle arrest at the G1 phase. The expression levels of cdk1, cdk2, cyclin A, and cyclin E were downregulated by simvastatin in a dose-dependent manner. The inhibitory effect of simvastatin was proved to mediate the reduction of mevalonate, and the addition of exogenous GGPP completely prevented the inhibitory effect of simvastatin on tendon cells. The present study demonstrated, for the first time, the molecular mechanism underlying simvastatin-induced tendinopathy or tendon rupture. GGPP was shown to prevent the adverse effect of simvastatin in tendon cells without interfering with its cholesterol-reducing efficacy. PMID:26577051

  5. TRPV3 Channel Negatively Regulates Cell Cycle Progression and Safeguards the Pluripotency of Embryonic Stem Cells.

    Science.gov (United States)

    Lo, Iek Chi; Chan, Hing Chung; Qi, Zenghua; Ng, Kwun Lam; So, Chun; Tsang, Suk Ying

    2016-02-01

    Embryonic stem cells (ESCs) have tremendous potential for research and future therapeutic purposes. However, the calcium handling mechanism in ESCs is not fully elucidated. Aims of this study are (1) to investigate if transient receptor potential vanilloid-3 (TRPV3) channels are present in mouse ESCs (mESCs) and their subcellular localization; (2) to investigate the role of TRPV3 in maintaining the characteristics of mESCs. Western blot and immunocytochemistry showed that TRPV3 was present at the endoplasmic reticulum (ER) of mESCs. Calcium imaging showed that, in the absence of extracellular calcium, TRPV3 activators camphor and 6-tert-butyl-m-cresol increased the cytosolic calcium. However, depleting the ER store in advance of activator addition abolished the calcium increase, suggesting that TRPV3 released calcium from the ER. To dissect the functional role of TRPV3, TRPV3 was activated and mESC proliferation was measured by trypan blue exclusion and MTT assays. The results showed that TRPV3 activation led to a decrease in mESC proliferation. Cell cycle analysis revealed that TRPV3 activation increased the percentage of cells in G2 /M phase; consistently, Western blot also revealed a concomitant increase in the expression of inactive form of cyclin-dependent kinase 1, suggesting that TRPV3 activation arrested mESCs at G2 /M phase. TRPV3 activation did not alter the expression of pluripotency markers Oct-4, Klf4 and c-Myc, suggesting that the pluripotency was preserved. Our study is the first study to show the presence of TRPV3 at ER. Our study also reveals the novel role of TRPV3 in controlling the cell cycle and preserving the pluripotency of ESCs. PMID:26130157

  6. A generalized model for multi-marker analysis of cell cycle progression in synchrony experiments

    OpenAIRE

    Mayhew, Michael B.; Joshua W. Robinson; Jung, Boyoun; Haase, Steven B.; Alexander J Hartemink

    2011-01-01

    Motivation: To advance understanding of eukaryotic cell division, it is important to observe the process precisely. To this end, researchers monitor changes in dividing cells as they traverse the cell cycle, with the presence or absence of morphological or genetic markers indicating a cell's position in a particular interval of the cell cycle. A wide variety of marker data is available, including information-rich cellular imaging data. However, few formal statistical methods have been develop...

  7. A novel quantitative model of cell cycle progression based on cyclin-dependent kinases activity and population balances.

    Science.gov (United States)

    Pisu, Massimo; Concas, Alessandro; Cao, Giacomo

    2015-04-01

    Cell cycle regulates proliferative cell capacity under normal or pathologic conditions, and in general it governs all in vivo/in vitro cell growth and proliferation processes. Mathematical simulation by means of reliable and predictive models represents an important tool to interpret experiment results, to facilitate the definition of the optimal operating conditions for in vitro cultivation, or to predict the effect of a specific drug in normal/pathologic mammalian cells. Along these lines, a novel model of cell cycle progression is proposed in this work. Specifically, it is based on a population balance (PB) approach that allows one to quantitatively describe cell cycle progression through the different phases experienced by each cell of the entire population during its own life. The transition between two consecutive cell cycle phases is simulated by taking advantage of the biochemical kinetic model developed by Gérard and Goldbeter (2009) which involves cyclin-dependent kinases (CDKs) whose regulation is achieved through a variety of mechanisms that include association with cyclins and protein inhibitors, phosphorylation-dephosphorylation, and cyclin synthesis or degradation. This biochemical model properly describes the entire cell cycle of mammalian cells by maintaining a sufficient level of detail useful to identify check point for transition and to estimate phase duration required by PB. Specific examples are discussed to illustrate the ability of the proposed model to simulate the effect of drugs for in vitro trials of interest in oncology, regenerative medicine and tissue engineering. PMID:25601491

  8. Glucosylceramide synthesis inhibition affects cell cycle progression, membrane trafficking, and stage differentiation in Giardia lamblia.

    Science.gov (United States)

    Stefanić, Sasa; Spycher, Cornelia; Morf, Laura; Fabriàs, Gemma; Casas, Josefina; Schraner, Elisabeth; Wild, Peter; Hehl, Adrian B; Sonda, Sabrina

    2010-09-01

    Synthesis of glucosylceramide via glucosylceramide synthase (GCS) is a crucial event in higher eukaryotes, both for the production of complex glycosphingolipids and for regulating cellular levels of ceramide, a potent antiproliferative second messenger. In this study, we explored the dependence of the early branching eukaryote Giardia lamblia on GCS activity. Biochemical analyses revealed that the parasite has a GCS located in endoplasmic reticulum (ER) membranes that is active in proliferating and encysting trophozoites. Pharmacological inhibition of GCS induced aberrant cell division, characterized by arrest of cytokinesis, incomplete cleavage furrow formation, and consequent block of replication. Importantly, we showed that increased ceramide levels were responsible for the cytokinesis arrest. In addition, GCS inhibition resulted in prominent ultrastructural abnormalities, including accumulation of cytosolic vesicles, enlarged lysosomes, and clathrin disorganization. Moreover, anterograde trafficking of the encystations-specific protein CWP1 was severely compromised and resulted in inhibition of stage differentiation. Our results reveal novel aspects of lipid metabolism in G. lamblia and specifically highlight the vital role of GCS in regulating cell cycle progression, membrane trafficking events, and stage differentiation in this parasite. In addition, we identified ceramide as a potent bioactive molecule, underscoring the universal conservation of ceramide signaling in eukaryotes. PMID:20335568

  9. Coordinated control of Notch/Delta signalling and cell cycle progression drives lateral inhibition-mediated tissue patterning

    Science.gov (United States)

    Hadjivasiliou, Zena; Bonin, Hope; He, Li; Perrimon, Norbert; Charras, Guillaume; Baum, Buzz

    2016-01-01

    Coordinating cell differentiation with cell growth and division is crucial for the successful development, homeostasis and regeneration of multicellular tissues. Here, we use bristle patterning in the fly notum as a model system to explore the regulatory and functional coupling of cell cycle progression and cell fate decision-making. The pattern of bristles and intervening epithelial cells (ECs) becomes established through Notch-mediated lateral inhibition during G2 phase of the cell cycle, as neighbouring cells physically interact with each other via lateral contacts and/or basal protrusions. Since Notch signalling controls cell division timing downstream of Cdc25, ECs in lateral contact with a Delta-expressing cell experience higher levels of Notch signalling and divide first, followed by more distant neighbours, and lastly Delta-expressing cells. Conversely, mitotic entry and cell division makes ECs refractory to lateral inhibition signalling, fixing their fate. Using a combination of experiments and computational modelling, we show that this reciprocal relationship between Notch signalling and cell cycle progression acts like a developmental clock, providing a delimited window of time during which cells decide their fate, ensuring efficient and orderly bristle patterning. PMID:27226324

  10. Coordinated control of Notch/Delta signalling and cell cycle progression drives lateral inhibition-mediated tissue patterning.

    Science.gov (United States)

    Hunter, Ginger L; Hadjivasiliou, Zena; Bonin, Hope; He, Li; Perrimon, Norbert; Charras, Guillaume; Baum, Buzz

    2016-07-01

    Coordinating cell differentiation with cell growth and division is crucial for the successful development, homeostasis and regeneration of multicellular tissues. Here, we use bristle patterning in the fly notum as a model system to explore the regulatory and functional coupling of cell cycle progression and cell fate decision-making. The pattern of bristles and intervening epithelial cells (ECs) becomes established through Notch-mediated lateral inhibition during G2 phase of the cell cycle, as neighbouring cells physically interact with each other via lateral contacts and/or basal protrusions. Since Notch signalling controls cell division timing downstream of Cdc25, ECs in lateral contact with a Delta-expressing cell experience higher levels of Notch signalling and divide first, followed by more distant neighbours, and lastly Delta-expressing cells. Conversely, mitotic entry and cell division makes ECs refractory to lateral inhibition signalling, fixing their fate. Using a combination of experiments and computational modelling, we show that this reciprocal relationship between Notch signalling and cell cycle progression acts like a developmental clock, providing a delimited window of time during which cells decide their fate, ensuring efficient and orderly bristle patterning. PMID:27226324

  11. Concerted control of DNA double strand break repair and cell cycle progression in X-irradiated mammalian cells

    International Nuclear Information System (INIS)

    Upon examination of cell cycle regulation in a damaged cell, relations were discovered of the cell cycle control mechanisms with a complicated web of signalling pathways, eventually called the genome surveillance system. After infliction of DNA double strand breaks (DSB), the signalling is initiated by sensor proteins and transducer protein kinase ATM. This kinase phosphorylates downstream effector proteins, such as checkpoint kinases CHK1 and CHK2, which initiate the pathways leading to cell cycle arrest. In contrast with the older model of linear transmission of signals in a certain sequence, it is now accepted that the damage signalling system is branched and contains feedback loops. DSB's presence is signalled by sensor proteins (MRE11-RAD50-nibrin complex, MRN) to ATM and the signal is amplified through adaptor proteins, MDC1/NFBD1 or 53BP1 (Tp53 binding protein). MRN contains a forkheadassociated (FHA) domain and BRCA1 carboxyl-terminal (BRCT) domain. The combination of the FHA/BRCT domains has a crucial role for the binding of nibrin to the H2AX histone, assembling the components of repair foci. These domains also are important for interaction of other proteins localised in the foci. For example, MDC1/NFBD1 contains a FHA domain and two BRCT domains which are involved in protein interactions. The signal generated at DSBs is amplified and transduced to recruit components of DNA repair systems. In a concerted way with the sequential recruitment of components of repair foci, activation of transcription of genes takes place, that is necessary for blocking progression through the cell cycle, for DNA repair or apoptosis. (author)

  12. A Robust Structural PGN Model for Control of Cell-Cycle Progression Stabilized by Negative Feedbacks

    Directory of Open Access Journals (Sweden)

    Nestor Walter Trepode

    2007-05-01

    Full Text Available The cell division cycle comprises a sequence of phenomena controlled by a stable and robust genetic network. We applied a probabilistic genetic network (PGN to construct a hypothetical model with a dynamical behavior displaying the degree of robustness typical of the biological cell cycle. The structure of our PGN model was inspired in well-established biological facts such as the existence of integrator subsystems, negative and positive feedback loops, and redundant signaling pathways. Our model represents genes interactions as stochastic processes and presents strong robustness in the presence of moderate noise and parameters fluctuations. A recently published deterministic yeast cell-cycle model does not perform as well as our PGN model, even upon moderate noise conditions. In addition, self stimulatory mechanisms can give our PGN model the possibility of having a pacemaker activity similar to the observed in the oscillatory embryonic cell cycle.

  13. A Robust Structural PGN Model for Control of Cell-Cycle Progression Stabilized by Negative Feedbacks

    Directory of Open Access Journals (Sweden)

    Armelin Hugo

    2007-01-01

    Full Text Available The cell division cycle comprises a sequence of phenomena controlled by a stable and robust genetic network. We applied a probabilistic genetic network (PGN to construct a hypothetical model with a dynamical behavior displaying the degree of robustness typical of the biological cell cycle. The structure of our PGN model was inspired in well-established biological facts such as the existence of integrator subsystems, negative and positive feedback loops, and redundant signaling pathways. Our model represents genes interactions as stochastic processes and presents strong robustness in the presence of moderate noise and parameters fluctuations. A recently published deterministic yeast cell-cycle model does not perform as well as our PGN model, even upon moderate noise conditions. In addition, self stimulatory mechanisms can give our PGN model the possibility of having a pacemaker activity similar to the observed in the oscillatory embryonic cell cycle.

  14. Cep55 regulates spindle organization and cell cycle progression in meiotic oocyte.

    Science.gov (United States)

    Xu, Zhao-Yang; Ma, Xue-Shan; Qi, Shu-Tao; Wang, Zhen-Bo; Guo, Lei; Schatten, Heide; Sun, Qing-Yuan; Sun, Ying-Pu

    2015-01-01

    Cep55 is a relatively novel member of the centrosomal protein family. Here, we show that Cep55 is expressed in mouse oocytes from the germinal vesicle (GV) to metaphase II (MII) stages. Immuostaining and confocal microscopy as well as time lapse live imaging after injection of mRNA encoding fusion protein of Cep55 and GFP identified that Cep55 was localized to the meiotic spindle, especially to the spindle poles at metaphase, while it was concentrated at the midbody in telophase in meiotic oocytes. Knockdown of Cep55 by specific siRNA injection caused the dissociation of γ-tubulin from the spindle poles, resulting in severely defective spindles and misaligned chromosomes, leading to metaphase I arrest and failure of first polar body (PB1) extrusion. Correspondingly, cyclin B accumulation and spindle assembly checkpoint (SAC) activation were observed in Cep55 knockdown oocytes. Our results suggest that Cep55 may act as an MTOC-associated protein regulating spindle organization, and thus cell cycle progression during mouse oocyte meiotic maturation. PMID:26582107

  15. Idas, a novel phylogenetically conserved geminin-related protein, binds to geminin and is required for cell cycle progression.

    Science.gov (United States)

    Pefani, Dafni-Eleutheria; Dimaki, Maria; Spella, Magda; Karantzelis, Nickolas; Mitsiki, Eirini; Kyrousi, Christina; Symeonidou, Ioanna-Eleni; Perrakis, Anastassis; Taraviras, Stavros; Lygerou, Zoi

    2011-07-01

    Development and homeostasis of multicellular organisms relies on an intricate balance between cell proliferation and differentiation. Geminin regulates the cell cycle by directly binding and inhibiting the DNA replication licensing factor Cdt1. Geminin also interacts with transcriptional regulators of differentiation and chromatin remodelling factors, and its balanced interactions are implicated in proliferation-differentiation decisions during development. Here, we describe Idas (Idas being a cousin of the Gemini in Ancient Greek Mythology), a previously uncharacterised coiled-coil protein related to Geminin. We show that human Idas localizes to the nucleus, forms a complex with Geminin both in cells and in vitro through coiled-coil mediated interactions, and can change Geminin subcellular localization. Idas does not associate with Cdt1 and prevents Geminin from binding to Cdt1 in vitro. Idas depletion from cells affects cell cycle progression; cells accumulate in S phase and are unable to efficiently progress to mitosis. Idas protein levels decrease in anaphase, whereas its overexpression causes mitotic defects. During development, we show that Idas exhibits high level expression in the choroid plexus and the cortical hem of the mouse telencephalon. Our data highlight Idas as a novel Geminin binding partner, implicated in cell cycle progression, and a putative regulator of proliferation-differentiation decisions during development. PMID:21543332

  16. Signals involved in T cell activation. II. Distinct roles of intact accessory cells, phorbol esters, and interleukin 1 in activation and cell cycle progression of resting T lymphocytes

    Energy Technology Data Exchange (ETDEWEB)

    Davis, L.; Lipsky, P.E.

    1986-05-15

    The signals involved in the initiation of mitogen-induced activation of resting guinea pig T cells were examined. The combination of phytohemagglutinin (PHA) and 4..beta..-phorbol 12-myristate 13-acetate (PMA) stimulated DNA synthesis by accessory cell (AC)-depleted T cells cultured at high density, but the use of low density cultures indicated that intact AC were absolutely necessary for PHA-stimulated T cell DNA synthesis even in the presence of PMA, interleukin 1 (IL 1), or interleukin 2 (IL 2). In contrast, AC-depleted T cells were able to respond to the combination of the calcium ionophore, ionomycin, and PMA regardless of the cell density at which they were cultured. Results of cell cycle analysis support the conclusion that intact AC, IL 1, and a PMA-like signal play distinct roles in the progression of mitogen stimulated T cells through the first round of the cell cycle.

  17. TSPY potentiates cell proliferation and tumorigenesis by promoting cell cycle progression in HeLa and NIH3T3 cells

    International Nuclear Information System (INIS)

    TSPY is a repeated gene mapped to the critical region harboring the gonadoblastoma locus on the Y chromosome (GBY), the only oncogenic locus on this male-specific chromosome. Elevated levels of TSPY have been observed in gonadoblastoma specimens and a variety of other tumor tissues, including testicular germ cell tumors, prostate cancer, melanoma, and liver cancer. TSPY contains a SET/NAP domain that is present in a family of cyclin B and/or histone binding proteins represented by the oncoprotein SET and the nucleosome assembly protein 1 (NAP1), involved in cell cycle regulation and replication. To determine a possible cellular function for TSPY, we manipulated the TSPY expression in HeLa and NIH3T3 cells using the Tet-off system. Cell proliferation, colony formation assays and tumor growth in nude mice were utilized to determine the TSPY effects on cell growth and tumorigenesis. Cell cycle analysis and cell synchronization techniques were used to determine cell cycle profiles. Microarray and RT-PCR were used to investigate gene expression in TSPY expressing cells. Our findings suggest that TSPY expression increases cell proliferation in vitro and tumorigenesis in vivo. Ectopic expression of TSPY results in a smaller population of the host cells in the G2/M phase of the cell cycle. Using cell synchronization techniques, we show that TSPY is capable of mediating a rapid transition of the cells through the G2/M phase. Microarray analysis demonstrates that numerous genes involved in the cell cycle and apoptosis are affected by TSPY expression in the HeLa cells. These data, taken together, have provided important insights on the probable functions of TSPY in cell cycle progression, cell proliferation, and tumorigenesis

  18. Non-DBS DNA Repair Genes Regulate Radiation-induced Cytogenetic Damage Repair and Cell Cycle Progression

    Science.gov (United States)

    Zhang, Ye; Rohde, Larry H.; Emami, Kamal; Casey, Rachael; Wu, Honglu

    2008-01-01

    Changes of gene expression profile are one of the most important biological responses in living cells after ionizing radiation (IR) exposure. Although some studies have shown that genes up-regulated by IR may play important roles in DNA damage repair, the relationship between the regulation of gene expression by IR, particularly genes not known for their roles in DSB repair, and its impact on cytogenetic responses has not been systematically studied. In the present study, the expression of 25 genes selected on the basis of their transcriptional changes in response to IR was individually knocked down by transfection with small interfering RNA in human fibroblast cells. The purpose of this study is to identify new roles of these selected genes on regulating DSB repair and cell cycle progression , as measured in the micronuclei formation and chromosome aberration. In response to IR, the formation of MN was significantly increased by suppressed expression of 5 genes: Ku70 in the DSB repair pathway, XPA in the NER pathway, RPA1 in the MMR pathway, and RAD17 and RBBP8 in cell cycle control. Knocked-down expression of 4 genes (MRE11A, RAD51 in the DSB pathway, SESN1, and SUMO1) significantly inhibited cell cycle progression, possibly because of severe impairment of DNA damage repair. Furthermore, loss of XPA, P21, or MLH1 expression resulted in both significantly enhanced cell cycle progression and increased yields of chromosome aberrations, indicating that these gene products modulate both cell cycle control and DNA damage repair. Most of the 11 genes that affected cytogenetic responses are not known to have clear roles influencing DBS repair. Nine of these 11 genes were up-regulated in cells exposed to gamma radiation, suggesting that genes transcriptionally modulated by IR were critical to regulate the biological consequences after IR.

  19. Human Transcription Factor hTAFII150 (CIF150) Is Involved in Transcriptional Regulation of Cell Cycle Progression

    OpenAIRE

    Martin, Jay; Halenbeck, Robert; Kaufmann, Jörg

    1999-01-01

    Here we present evidence that CIF150 (hTAFII150), the human homolog of Drosophila TAFII150, plays an important and selective role in establishing gene expression patterns necessary for progression through the cell cycle. Gel filtration experiments demonstrate that CIF150 (hTAFII150) seems to be less tightly associated with human transcription factor IID than hTAFII130 is associated with hTAFII250. The transient functional knockout of CIF150 (hTAFII150) protein led to cell cycle arrest at the ...

  20. A Cis-Acting tRNA Gene Imposes the Cell Cycle Progression Requirement for Establishing Silencing at the HMR Locus in Yeast

    OpenAIRE

    Lazarus, Asmitha G.; Holmes, Scott G

    2011-01-01

    Numerous studies have determined that the establishment of Sir protein-dependent transcriptional silencing in yeast requires progression through the cell cycle. In our study we examined the cell cycle requirement for the establishment of silencing at the HML and HMR loci using strains bearing conditional or inducible SIR3 alleles. Consistent with prior reports, we observed that establishing silencing at HMR required progression through the cell cycle. Unexpectedly, we found that the HML locus...

  1. Effect of curcumin on cell cycle progression and apoptosis in vascular smooth muscle cells

    OpenAIRE

    Chen, Huei-Wen; Huang, Huei-Chen

    1998-01-01

    The possible mechanisms of the antiproliferative and apoptotic effects of curcumin (diferuloylmethane), a polyphenol in the spice turmeric, on vascular smooth muscle cells were studied in rat aortic smooth muscle cell line (A7r5).The proliferative response was determined from the uptake of [3H]-thymidine. Curcumin (10−6–10−4 M) inhibited serum-stimulated [3H]-thymidine incorporation of both A7r5 cells and rabbit cultured vascular smooth muscle cells in a concentration-dependent manner. Cell v...

  2. A central to peripheral progression of cell cycle exit and hair cell differentiation in the developing mouse cristae.

    Science.gov (United States)

    Slowik, Amber D; Bermingham-McDonogh, Olivia

    2016-03-01

    The inner ear contains six distinct sensory organs that each maintains some ability to regenerate hair cells into adulthood. In the postnatal cochlea, there appears to be a relationship between the developmental maturity of a region and its ability to regenerate as postnatal regeneration largely occurs in the apical turn, which is the last region to differentiate and mature during development. In the mature cristae there are also regional differences in regenerative ability, which led us to hypothesize that there may be a general relationship between the relative maturity of a region and the regenerative competence of that region in all of the inner ear sensory organs. By analyzing adult mouse cristae labeled embryonically with BrdU, we found that hair cell birth starts in the central region and progresses to the periphery with age. Since the peripheral region of the adult cristae also maintains active Notch signaling and some regenerative competence, these results are consistent with the hypothesis that the last regions to develop retain some of their regenerative ability into adulthood. Further, by analyzing embryonic day 14.5 inner ears we provide evidence for a wave of hair cell birth along the longitudinal axis of the cristae from the central regions to the outer edges. Together with the data from the adult inner ears labeled with BrdU as embryos, these results suggest that hair cell differentiation closely follows cell cycle exit in the cristae, unlike in the cochlea where they are uncoupled. PMID:26826497

  3. The tankyrase-specific inhibitor JW74 affects cell cycle progression and induces apoptosis and differentiation in osteosarcoma cell lines

    International Nuclear Information System (INIS)

    Wnt/β-catenin is a major regulator of stem cell self-renewal and differentiation and this signaling pathway is aberrantly activated in a several cancers, including osteosarcoma (OS). Attenuation of Wnt/β-catenin activity by tankyrase inhibitors is an appealing strategy in treatment of OS. The efficacy of the tankyrase inhibitor JW74 was evaluated in three OS cell lines (KPD, U2OS, and SaOS-2) both at the molecular and functional level. At the molecular level, JW74 induces stabilization of AXIN2, a key component of the β-catenin destruction complex, resulting in reduced levels of nuclear β-catenin. At the functional level, JW74 induces reduced cell growth in all three tested cell lines, in part due to a delay in cell cycle progression and in part due to an induction of caspase-3-mediated apoptosis. Furthermore, JW74 induces differentiation in U2OS cells, which under standard conditions are resistant to osteogenic differentiation. JW74 also enhances differentiation of OS cell lines, which do not harbor a differentiation block. Interestingly, microRNAs (miRNAs) of the let-7 family, which are known tumor suppressors and inducers of differentiation, are significantly upregulated following treatment with JW74. We demonstrate for the first time that tankyrase inhibition triggers reduced cell growth and differentiation of OS cells. This may in part be due to an induction of let-7 miRNA. The presented data open for novel therapeutic strategies in the treatment of malignant OS

  4. Sphingosine-1-phosphate receptor 3 influences cell cycle progression in muscle satellite cells

    OpenAIRE

    Fortier, Mathieu; Figeac, Nicolas; White, Robert B.; Knopp, Paul; Zammit, Peter S.

    2013-01-01

    Skeletal muscle retains a resident stem cell population called satellite cells, which are mitotically quiescent in mature muscle, but can be activated to produce myoblast progeny for muscle homeostasis, hypertrophy and repair. We have previously shown that satellite cell activation is partially controlled by the bioactive phospholipid, sphingosine-1-phosphate, and that S1P biosynthesis is required for muscle regeneration. Here we investigate the role of sphingosine-1-phosphate receptor 3 (S1P...

  5. Perturbations of cell-cycle progression in γ-irradiated ataxia telangiectasia and Huntington's disease cells detected by DNA flow cytometric analysis

    International Nuclear Information System (INIS)

    The effects of ionizing radiation on cell-cycle progression in lymphoblastoid cell lines derived from ataxia telangiectasia (AT) and Huntington's disease (HD) patients, and from normal individuals, were studied using DNA flow cytometric analysis. A dose of 100 rad γ irradiation blocked a proportion of normal and HD cells in G1. A higher radiation dose applied to normal cells increased the number of cells blocked in G1 and significantly delayed cells which were in S at the time of irradiation from reaching G2 DNA content. The reduced cumulative mitotic index in irradiated cultures of normal cells 2 h after irradiation suggests that cells in G2 at the time of irradiation are delayed before entering mitosis. After irradiation HD cells responded similarly to normal cells except that a greater proportion of HD cells were blocked in G1. AT cells do not show the normal delay in progression from G1 to S, or from S to G2 in the first cycle after irradiation. The cumulative mitotic index was reduced in irradiated cells, implying that they are delayed in G2. Thus AT cells did not recognize or respond to signals from damaged DNA which in normal and HD cells caused a proportional block in G1 and an S-phase delay. The only point of arrest in cell-cycle progression in irradiated AT cells was in G2. (Auth.)

  6. Kif11 dependent cell cycle progression in radial glial cells is required for proper neurogenesis in the zebrafish neural tube.

    Science.gov (United States)

    Johnson, Kimberly; Moriarty, Chelsea; Tania, Nessy; Ortman, Alissa; DiPietrantonio, Kristina; Edens, Brittany; Eisenman, Jean; Ok, Deborah; Krikorian, Sarah; Barragan, Jessica; Golé, Christophe; Barresi, Michael J F

    2014-03-01

    Radial glia serve as the resident neural stem cells in the embryonic vertebrate nervous system, and their proliferation must be tightly regulated to generate the correct number of neuronal and glial cell progeny in the neural tube. During a forward genetic screen, we recently identified a zebrafish mutant in the kif11 loci that displayed a significant increase in radial glial cell bodies at the ventricular zone of the spinal cord. Kif11, also known as Eg5, is a kinesin-related, plus-end directed motor protein responsible for stabilizing and separating the bipolar mitotic spindle. We show here that Gfap+ radial glial cells express kif11 in the ventricular zone and floor plate. Loss of Kif11 by mutation or pharmacological inhibition with S-trityl-L-cysteine (STLC) results in monoastral spindle formation in radial glial cells, which is characteristic of mitotic arrest. We show that M-phase radial glia accumulate over time at the ventricular zone in kif11 mutants and STLC treated embryos. Mathematical modeling of the radial glial accumulation in kif11 mutants not only confirmed an ~226× delay in mitotic exit (likely a mitotic arrest), but also predicted two modes of increased cell death. These modeling predictions were supported by an increase in the apoptosis marker, anti-activated Caspase-3, which was also found to be inversely proportional to a decrease in cell proliferation. In addition, treatment with STLC at different stages of neural development uncovered two critical periods that most significantly require Kif11 function for stem cell progression through mitosis. We also show that loss of Kif11 function causes specific reductions in oligodendroglia and secondary interneurons and motorneurons, suggesting these later born populations require proper radial glia division. Despite these alterations to cell cycle dynamics, survival, and neurogenesis, we document unchanged cell densities within the neural tube in kif11 mutants, suggesting that a mechanism of

  7. Anandamide drives cell cycle progression through CB1 receptors in a rat model of synchronized liver regeneration.

    Science.gov (United States)

    Pisanti, Simona; Picardi, Paola; Pallottini, Valentina; Martini, Chiara; Petrosino, Stefania; Proto, Maria Chiara; Vitale, Mario; Laezza, Chiara; Gazzerro, Patrizia; Di Marzo, Vincenzo; Bifulco, Maurizio

    2015-12-01

    The endocannabinoid system, through cannabinoid receptor signaling by endocannabinoids, is involved in a wide range of functions and physiopathological conditions. To date, very little is known concerning the role of the endocannabinoids in the control and regulation of cell proliferation. An anti-proliferative action of CB1 signaling blockade in neurogenesis and angiogenesis argues in favor of proliferation-promoting functions of endocannabinoids through CB1 receptors when pro-growth signals are present. Furthermore, liver regeneration, a useful in vivo model of synchronized cell proliferation, is characterized by a peak of anandamide that elicits through CB1 receptor, the expression of critical mitosis genes. The aim of this study was to focus on the timing of endocannabinoid signaling changes during the different phases of the cell cycle, exploiting the rat liver regeneration model following partial hepatectomy, the most useful to study synchronized cell cycle in vivo. Hepatic regeneration led to increased levels of anandamide and endocannabinoid-like molecules oleoylethanolamide (OEA) and palmitoylethanolamide (PEA) in the G1 phase of the cell cycle, with a concomitant increase in CB1 mRNA levels, whose protein expression peaked later during the S phase. Blocking of CB1 receptor with a low dose of the selective antagonist/inverse agonist SR141716 (0.7 mg/kg/dose) affected cell cycle progression reducing the expression of PCNA, and through the inhibition of pERK and pSTAT3 pathways. These results support the notion that the signaling mediated by anandamide through CB1 receptor may be important for the entry and progression of cells into the cell cycle and hence for their proliferation under mitogenic signals. PMID:25684344

  8. Methyl Jasmonate Represses Growth and Affects Cell Cycle Progression in Cultured Taxus Cells

    OpenAIRE

    Patil, Rohan A.; Lenka, Sangram K.; Normanly, Jennifer; Walker, Elsbeth L.; Roberts, Susan C.

    2014-01-01

    Methyl jasmonate (MeJA) elicitation is an effective strategy to induce and enhance synthesis of the anticancer agent paclitaxel (Taxol®) in Taxus cell suspension cultures; however, concurrent decreases in growth are often observed, which is problematic for large scale bioprocessing. Here, increased accumulation of paclitaxel in Taxus cuspidata suspension cultures with MeJA elicitation was accompanied by a concomitant decrease in cell growth, evident within the first three days post-elicitatio...

  9. Checkpoints Studies Using the Budding Yeast Saccharomyces cerevisiae: Analysis of changes in protein level and subcellular localization during cell cycle progression

    OpenAIRE

    Wu, Xiaorong; Liu, Lili; HUANG, Mingxia

    2011-01-01

    Methods are described here to monitor changes in protein level and subcellular localization during the cell cycle progression in the budding yeast S. cerevisiae. Cell synchronization is achieved by an α-factor mediated block-and-release protocol. Cells are collected at different time points for the first two cell cycles upon release. Cellular DNA contents are analyzed by flow cytometry. Trichloroacetic acid protein precipitates are prepared for monitoring levels of cell cycle regulated protei...

  10. Erythrocytes modulate cell cycle progression but not the baseline frequency of sister chromatid exchanges in pig lymphocytes

    Directory of Open Access Journals (Sweden)

    Miguel A. Reigosa

    1997-09-01

    Full Text Available The effect of co-culturing varying concentrations of pig and human red blood cells (RBCs on the baseline frequency of sister chromatid exchanges (SCEs and cell-cycle progression in pig plasma (PLCs and whole blood leukocyte cultures (WBCs was studied. No variation in SCE frequency was observed between pig control WBC and PLC. Addition of pig and human RBCs to pig PLCs did not modify the baseline frequency of SCEs. On the other hand, cell proliferation was slower in PLCs than in WBCs. The addition of pig or human RBCs to PLCs accelerated the cell-cycle progression of pig lymphocytes. When RBCs were added to PLCs the concentration and time sequence of RBC incorporation affected the cell-cycle progression of swine lymphocytes. When doses of pig or human RBCs equivalent to those present in WBCs were added immediately after PLC stimulation, the cell-cycle kinetics were similar to those of WBCs. Shorter co-incubation periods or a reduction in the dose of RBCs made cell-cycle progression intermediate between PLC and WBC values. Thus, pig and human RBCs modulated the in vitro cell-cycle progression of pig lymphocytes in a time- and dose-dependent manner, and the low baseline frequency of SCEs of pig lymphocytes is independent of the presence or absence of erythrocytes in cultureFoi estudado o efeito de co-culturas com concentrações variadas de células sangüíneas vermelhas (RBCs suínas e humanas na freqüência basal de trocas de cromátides irmãs (SCEs e na progressão do ciclo celular em culturas de plasma de porco (PLCs e culturas leucocitárias do sangue total (WBCs. Não foi observada nenhuma variação na freqüências de SCEs entre os controles de WBC e PLC em porcos. A adição de RBCs de suínos e humanos a PLCs não modificou a freqüência basal de SCEs. Por outro lado, a proliferação celular foi mais lenta em PLCs que em WBCs. A adição de RBCs humanas ou suínas a PLCs acelerou a progressão do ciclo celular de linfócitos su

  11. Reactive oxygen species, cell growth, cell cycle progression and vascular remodeling in hypertension

    Czech Academy of Sciences Publication Activity Database

    Vokurková, Martina; Xu, S.; Touyz, R.M.

    2007-01-01

    Roč. 3, č. 1 (2007), s. 53-63. ISSN 1479-6678 R&D Projects: GA MŠk(CZ) 1M0510 Institutional research plan: CEZ:AV0Z50110509 Keywords : cyclins * oxidative stress * cell proliferation Subject RIV: ED - Physiology

  12. Erythrocytes modulate cell cycle progression but not the baseline frequency of sister chromatid exchanges in pig lymphocytes

    OpenAIRE

    Miguel A. Reigosa; Sonia Soloneski; Garcia, Carlos F.; Larramendy, Marcelo L.

    1997-01-01

    The effect of co-culturing varying concentrations of pig and human red blood cells (RBCs) on the baseline frequency of sister chromatid exchanges (SCEs) and cell-cycle progression in pig plasma (PLCs) and whole blood leukocyte cultures (WBCs) was studied. No variation in SCE frequency was observed between pig control WBC and PLC. Addition of pig and human RBCs to pig PLCs did not modify the baseline frequency of SCEs. On the other hand, cell proliferation was slower in PLCs than in WBCs. The ...

  13. The Deadbeat Paternal Effect of Uncapped Sperm Telomeres on Cell Cycle Progression and Chromosome Behavior in Drosophila melanogaster.

    Science.gov (United States)

    Yamaki, Takuo; Yasuda, Glenn K; Wakimoto, Barbara T

    2016-06-01

    Telomere-capping complexes (TCCs) protect the ends of linear chromosomes from illegitimate repair and end-to-end fusions and are required for genome stability. The identity and assembly of TCC components have been extensively studied, but whether TCCs require active maintenance in nondividing cells remains an open question. Here we show that Drosophila melanogaster requires Deadbeat (Ddbt), a sperm nuclear basic protein (SNBP) that is recruited to the telomere by the TCC and is required for TCC maintenance during genome-wide chromatin remodeling, which transforms spermatids to mature sperm. Ddbt-deficient males produce sperm lacking TCCs. Their offspring delay the initiation of anaphase as early as cycle 1 but progress through the first two cycles. Persistence of uncapped paternal chromosomes induces arrest at or around cycle 3. This early arrest can be rescued by selective elimination of paternal chromosomes and production of gynogenetic haploid or haploid mosaics. Progression past cycle 3 can also occur if embryos have reduced levels of the maternally provided checkpoint kinase Chk2. The findings provide insights into how telomere integrity affects the regulation of the earliest embryonic cell cycles. They also suggest that other SNBPs, including those in humans, may have analogous roles and manifest as paternal effects on embryo quality. PMID:27029731

  14. Human Transcription Factor hTAFII150 (CIF150) Is Involved in Transcriptional Regulation of Cell Cycle Progression

    Science.gov (United States)

    Martin, Jay; Halenbeck, Robert; Kaufmann, Jörg

    1999-01-01

    Here we present evidence that CIF150 (hTAFII150), the human homolog of Drosophila TAFII150, plays an important and selective role in establishing gene expression patterns necessary for progression through the cell cycle. Gel filtration experiments demonstrate that CIF150 (hTAFII150) seems to be less tightly associated with human transcription factor IID than hTAFII130 is associated with hTAFII250. The transient functional knockout of CIF150 (hTAFII150) protein led to cell cycle arrest at the G2/M transition in mammalian cell lines. PCR display analysis with the RNA derived from CIF150-depleted cells indicated that CIF150 (hTAFII150) is required for the transcription of only a subset of RNA polymerase II genes. CIF150 (hTAFII150) directly stimulated cyclin B1 and cyclin A transcription in cotransfection assays and in vitro assays, suggesting that the expression of these genes is dependent on CIF150 (hTAFII150) function. We defined a CIF150 (hTAFII150) consensus binding site and demonstrated that a CIF150-responsive cis element is present in the cyclin B1 core promoter. These results suggest that one function of CIF150 (hTAFII150) is to select specific RNA polymerase II core promoter elements involved in cell cycle progression. PMID:10409744

  15. The B-MYB transcriptional network guides cell cycle progression and fate decisions to sustain self-renewal and the identity of pluripotent stem cells.

    Directory of Open Access Journals (Sweden)

    Ming Zhan

    Full Text Available Embryonic stem cells (ESCs are pluripotent and have unlimited self-renewal capacity. Although pluripotency and differentiation have been examined extensively, the mechanisms responsible for self-renewal are poorly understood and are believed to involve an unusual cell cycle, epigenetic regulators and pluripotency-promoting transcription factors. Here we show that B-MYB, a cell cycle regulated phosphoprotein and transcription factor critical to the formation of inner cell mass, is central to the transcriptional and co-regulatory networks that sustain normal cell cycle progression and self-renewal properties of ESCs. Phenotypically, B-MYB is robustly expressed in ESCs and induced pluripotent stem cells (iPSCs, and it is present predominantly in a hypo-phosphorylated state. Knockdown of B-MYB results in functional cell cycle abnormalities that involve S, G2 and M phases, and reduced expression of critical cell cycle regulators like ccnb1 and plk1. By conducting gene expression profiling on control and B-MYB deficient cells, ChIP-chip experiments, and integrative computational analyses, we unraveled a highly complex B-MYB-mediated transcriptional network that guides ESC self-renewal. The network encompasses critical regulators of all cell cycle phases and epigenetic regulators, pluripotency transcription factors, and differentiation determinants. B-MYB along with E2F1 and c-MYC preferentially co-regulate cell cycle target genes. B-MYB also co-targets genes regulated by OCT4, SOX2 and NANOG that are significantly associated with stem cell differentiation, embryonic development, and epigenetic control. Moreover, loss of B-MYB leads to a breakdown of the transcriptional hierarchy present in ESCs. These results coupled with functional studies demonstrate that B-MYB not only controls and accelerates cell cycle progression in ESCs it contributes to fate decisions and maintenance of pluripotent stem cell identity.

  16. Tafazzin knockdown interrupts cell cycle progression in cultured neonatal ventricular fibroblasts.

    Science.gov (United States)

    He, Quan; Wang, Miao; Harris, Nicole; Han, Xianlin

    2013-11-01

    Mutation of the mitochondrial protein tafazzin causes dilated cardiomyopathy in Barth syndrome. Previous studies have shown that tafazzin knockdown promotes hypertrophy of neonatal cardiac myocytes. The current investigation was designed to show whether tafazzin knockdown affects cardiac fibroblast proliferation and collagen secretion, which contribute to fibrosis in dilated cardiomyopathy. In primary cultures of neonatal ventricular fibroblasts (NVFs) transduced with a tafazzin short hairpin RNA adenovirus, tafazzin knockdown increased production of reactive oxygen species and activation of mitogen-activated protein kinases and induced protein and DNA synthesis via cell cycle regulators. It also reduced intracellular ATP, activated AMPK, and caused multinucleation, hypertrophy, and enhanced collagen secretion. We concluded that tafazzin knockdown interrupts the NVF cell cycle and this in turn may contribute to fibrosis and dilated cardiomyopathy in Barth syndrome. PMID:23997105

  17. The Homeodomain Iroquois Proteins Control Cell Cycle Progression and Regulate the Size of Developmental Fields.

    Directory of Open Access Journals (Sweden)

    Natalia Barrios

    2015-08-01

    Full Text Available During development, proper differentiation and final organ size rely on the control of territorial specification and cell proliferation. Although many regulators of these processes have been identified, how both are coordinated remains largely unknown. The homeodomain Iroquois/Irx proteins play a key, evolutionarily conserved, role in territorial specification. Here we show that in the imaginal discs, reduced function of Iroquois genes promotes cell proliferation by accelerating the G1 to S transition. Conversely, their increased expression causes cell-cycle arrest, down-regulating the activity of the Cyclin E/Cdk2 complex. We demonstrate that physical interaction of the Iroquois protein Caupolican with Cyclin E-containing protein complexes, through its IRO box and Cyclin-binding domains, underlies its activity in cell-cycle control. Thus, Drosophila Iroquois proteins are able to regulate cell-autonomously the growth of the territories they specify. Moreover, our results provide a molecular mechanism for a role of Iroquois/Irx genes as tumour suppressors.

  18. Downregulation of ROS-FIG inhibits cell proliferation, colony-formation, cell cycle progression, migration and invasion, while inducing apoptosis in intrahepatic cholangiocarcinoma cells

    Science.gov (United States)

    DENG, GANG; HU, CHENGHUAN; ZHU, LEI; HUANG, FEIZHOU; HUANG, WEI; XU, HONGBO; NIE, WANPIN

    2014-01-01

    Intrahepatic cholangiocarcinoma (ICC) is the second most common primary liver cancer with poor responsiveness to existing drug therapies. Therefore, novel treatment strategies against ICC are required to improve survival. The aim of this study was to demonstrate the role of fused-in-glioblastoma-c-ros-oncogene1 (FIG-ROS) fusion gene in ICC. ROS was positively expressed in ICC tissues and HUCCT1 cells. Plasmids expressing ROS- and FIG-specific shRNAs were constructed and transfected into HUCCT1 cells. The results showed that single transfection of ROS- or FIG-specific shRNA inhibited HUCCT1 cell proliferation, colony formation, cell cycle progression, migration and invasion, while inducing apoptosis. Moreover, the co-inhibition of ROS- and FIG-specific shRNA exhibited stronger effects on HUCCT1 cell proliferation, apoptosis, colony formation, cell cycle progression, migration and invasion, when compared to single inhibition of ROS and FIG. Furthermore, findings of this study suggested that the AKT signaling pathway was involved in the ROS-FIG-mediated biological processes of HUCCT1 cells. In summary, the results suggest that FIG-ROS plays an oncogenic role in ICC. Additionally, ROS1-6290 and FIG-363 segments may become effective therapeutic targets for ICC harboring ROS-FIG fusion protein. PMID:24968753

  19. Effects of ethanol on hepatic cellular replication and cell cycle progression

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Ethanol is a hepatotoxin. It appears that the liver is the target of ethanol induced toxicity primarily because it is the major site of ethanol metabolism. Metabolism of ethanol results in a number of biochemical changes that are thought to mediate the toxicity associated with ethanol abuse. These include the production of acetaldehyde and reactive oxygen species, as well as an accumulation of nicotinamide adenine dinucleotide(NADH). These biochemical changes are associated with the accumulation of fat and mitochondrial dysfunction in the liver. If these changes are severe enough they can themselves cause hepatotoxicity, or they can sensitize the liver to more severe damage by other hepatotoxins.Whether liver damage is the result of ethanol metabolism or some other hepatotoxin, recovery of the liver from damage requires replacement of cells that have been destroyed. It is now apparent that ethanol metabolism not only causes hepatotoxicity but also impairs the replication of normal hepatocytes. This impairment has been shown to occur at both the G1/S, and the G2/M transitions of the cell cycle. These impairments may be the result of activation of the checkpoint kinases, which can mediate cell cycle arrest at both of these transitions.Conversely, because ethanol metabolism results in a number of biochemical changes, there may be a number of mechanisms by which ethanol metabolism impairs cellular replication. It is the goal of this article to review the mechanisms by which ethanol metabolism mediates impairment of hepatic replication.

  20. Carnitine palmitoyltransferase 1A functions to repress FoxO transcription factors to allow cell cycle progression in ovarian cancer.

    Science.gov (United States)

    Shao, Huanjie; Mohamed, Esraa M; Xu, Guoyan G; Waters, Michael; Jing, Kai; Ma, Yibao; Zhang, Yan; Spiegel, Sarah; Idowu, Michael O; Fang, Xianjun

    2016-01-26

    Cancer cells rely on hyperactive de novo lipid synthesis for maintaining malignancy. Recent studies suggest involvement in cancer of fatty acid oxidation, a process functionally opposite to lipogenesis. A mechanistic link from lipid catabolism to oncogenic processes is yet to be established. Carnitine palmitoyltransferase 1 (CPT1) is a rate-limiting enzyme of fatty acid β-oxidation (FAO) that catalyzes the transfer of long-chain acyl group of the acyl-CoA ester to carnitine, thereby shuttling fatty acids into the mitochondrial matrix for β-oxidation. In the present study, we demonstrated that CPT1A was highly expressed in most ovarian cancer cell lines and primary ovarian serous carcinomas. Overexpression of CPT1A correlated with a poor overall survival of ovarian cancer patients. Inactivation of CPT1A decreased cellular ATP levels and induced cell cycle arrest at G0/G1, suggesting that ovarian cancer cells depend on or are addicted to CPT1A-mediated FAO for cell cycle progression. CPT1A deficiency also suppressed anchorage-independent growth and formation of xenografts from ovarian cancer cell lines. The cyclin-dependent kinase inhibitor p21WAF1 (p21) was identified as most consistently and robustly induced cell cycle regulator upon inactivation of CPT1A. Furthermore, p21 was transcriptionally upregulated by the FoxO transcription factors, which were in turn phosphorylated and activated by AMP-activated protein kinase and the mitogen-activated protein kinases JNK and p38. Our results established the oncogenic relevance of CPT1A and a mechanistic link from lipid catabolism to cell cycle regulation, suggesting that CPT1A could be a prognostic biomarker and rational target for therapeutic intervention of cancer. PMID:26716645

  1. A genomic multi-process survey of the machineries that control and link cell shape, microtubule organisation and cell cycle progression

    OpenAIRE

    Graml, Veronika; Studera, Xenia; Lawson, Jonathan L.D.; Chessel, Anatole; Geymonat, Marco; Bortfeld-Miller, Miriam; Walter, Thomas; Wagstaff, Laura; Piddini, Eugenia; Carazo Salas, Rafael E.

    2014-01-01

    Understanding cells as integrated systems requires that we systematically decipher how single genes affect multiple biological processes and how processes are functionally linked. Here, we used multi-process phenotypic profiling, combining high-resolution 3D confocal microscopy and multi-parametric image analysis, to simultaneously survey the fission yeast genome with respect to three key cellular processes: cell shape, microtubule organisation and cell cycle progression. We identify, validat...

  2. Expression of G protein-coupled receptor 19 in human lung cancer cells is triggered by entry into S phase and supports G2/M cell cycle progression

    International Nuclear Information System (INIS)

    G protein-coupled receptors (GPCRs) represent the largest family of cell surface receptors. However, only a fraction of the more than 800 receptors have been characterized to an extent that their physiological role is reasonably well understood. In fact, current pharmacotherapy only addresses some 60 receptors with a large collection of compounds that represent about 30% of the available drugs. It has long been known that GPCRs are subject to illegitimate expression in cancer cells. Presumably, hijacking the normal physiological functions of GPCRs contributes to all biological capabilities acquired during the multistep development of human cancers. With the goal of linking G protein-coupled receptors to malignant diseases, GPCRs were searched for that revealed high expression levels in small cell lung cancer (SCLC): The mRNA encoding orphan G protein-coupled receptor 19 (GPR19) was found to be frequently overexpressed in tissue samples obtained from patients with SCLC in contrast to samples derived from non-SCLC or normal lung. Several observations indicate that overexpression of Gpr19 confers a specific advantage to human lung cancer-derived cells regarding the transition through the cell cycle. Knockdown of Gpr19 mRNA by RNA interference reduced cell growth of human lung cancer cell lines and led to cell death. Cell cycle progression through G2/M phase was impaired and this was associated with increased protein levels of cyclin B1 and phosphorylated histone H3. Gpr19 exhibited a cell cycle-dependent expression pattern in lung cancer cell lines. When cell cycle distribution profiles of cells released from cell cycle arrest were related to Gpr19 mRNA levels, a peak Gpr19 expression was detected during S phase. The control of Gpr19 expression by E2F transcription factors, which drive gene expression of many genes important for cell cycle progression, was verified by chromatin immunoprecipitation: Antibodies directed against E2F-1 to E2F-4 allowed for the recovery of

  3. Does MW Radiation Affect Gene Expression, Apoptotic Level, and Cell Cycle Progression of Human SH-SY5Y Neuroblastoma Cells?

    Science.gov (United States)

    Kayhan, Handan; Esmekaya, Meric Arda; Saglam, Atiye Seda Yar; Tuysuz, Mehmed Zahid; Canseven, Ayşe Gulnihal; Yagci, Abdullah Munci; Seyhan, Nesrin

    2016-06-01

    Neuroblastoma (NB) is a cancer that occurs in sympathetic nervous system arising from neuroblasts and nerve tissue of the adrenal gland, neck, chest, or spinal cord. It is an embryonal malignancy and affects infants and children. In this study, we investigated the effects of microwave (MW) radiation on apoptotic activity, cell viability, and cell cycle progression in human SH-SY5Y NB cells which can give information about MW radiation effects on neural cells covering the period from the embryonic stages to infants. SH-SY5Y NB cells were exposed to 2.1 GHz W-CDMA modulated MW radiation for 24 h at a specific absorption rate of 0.491 W/kg. Control samples were in the same conditions with MW-exposed samples but they were not exposed to MW radiation. The apoptotic activity of cells was measured by Annexin-V-FITC and propidium iodide staining. Moreover, mRNA levels of proliferative and cell cycle proteins were determined by real-time RT-PCR. The change in cell cycle progression was observed by using CycleTest-Plus DNA reagent. No significant change was observed in apoptotic activity of MW-exposed cells compared to control cells. The mRNA levels of c-myc and cyclin D1 were significantly reduced in MW group (p CDMA modulated MW radiation did not cause apoptotic cell death but changed cell cycle progression. PMID:27260669

  4. RNA interference-mediated silencing of mitotic kinesin KIF14 disrupts cell cycle progression and induces cytokinesis failure.

    Science.gov (United States)

    Carleton, Michael; Mao, Mao; Biery, Matthew; Warrener, Paul; Kim, Sammy; Buser, Carolyn; Marshall, C Gary; Fernandes, Christine; Annis, James; Linsley, Peter S

    2006-05-01

    KIF14 is a microtubule motor protein whose elevated expression is associated with poor-prognosis breast cancer. Here we demonstrate KIF14 accumulation in mitotic cells, where it associated with developing spindle poles and spindle microtubules. Cells at later stages of mitosis were characterized by the concentration of KIF14 at the midbody. Time-lapse microscopy revealed that strong RNA interference (RNAi)-mediated silencing of KIF14 induced cytokinesis failure, causing several rounds of endoreduplication and resulting in multinucleated cells. Additionally, less efficacious KIF14-specific short interfering RNAs (siRNAs) induced multiple phenotypes, all of which resulted in acute apoptosis. Our data demonstrate the ability of siRNA-mediated silencing to generate epiallelic hypomorphs associated with KIF14 depletion. Furthermore, the link we observed between siRNA efficacy and phenotypic outcome indicates that distinct stages during cell cycle progression are disrupted by the differential modulation of KIF14 expression. PMID:16648480

  5. Two-component signal transduction pathways regulating growth and cell cycle progression in a bacterium: a system-level analysis.

    Directory of Open Access Journals (Sweden)

    Jeffrey M Skerker

    2005-10-01

    Full Text Available Two-component signal transduction systems, comprised of histidine kinases and their response regulator substrates, are the predominant means by which bacteria sense and respond to extracellular signals. These systems allow cells to adapt to prevailing conditions by modifying cellular physiology, including initiating programs of gene expression, catalyzing reactions, or modifying protein-protein interactions. These signaling pathways have also been demonstrated to play a role in coordinating bacterial cell cycle progression and development. Here we report a system-level investigation of two-component pathways in the model organism Caulobacter crescentus. First, by a comprehensive deletion analysis we show that at least 39 of the 106 two-component genes are required for cell cycle progression, growth, or morphogenesis. These include nine genes essential for growth or viability of the organism. We then use a systematic biochemical approach, called phosphotransfer profiling, to map the connectivity of histidine kinases and response regulators. Combining these genetic and biochemical approaches, we identify a new, highly conserved essential signaling pathway from the histidine kinase CenK to the response regulator CenR, which plays a critical role in controlling cell envelope biogenesis and structure. Depletion of either cenK or cenR leads to an unusual, severe blebbing of cell envelope material, whereas constitutive activation of the pathway compromises cell envelope integrity, resulting in cell lysis and death. We propose that the CenK-CenR pathway may be a suitable target for new antibiotic development, given previous successes in targeting the bacterial cell wall. Finally, the ability of our in vitro phosphotransfer profiling method to identify signaling pathways that operate in vivo takes advantage of an observation that histidine kinases are endowed with a global kinetic preference for their cognate response regulators. We propose that this

  6. THE MULTIPLE ROLES OF CYCLIN E1 IN CONTROLLING CELL CYCLE PROGRESSION AND CELLULAR MORPHOLOGY OF TRYPANOSOMA BRUCEI

    OpenAIRE

    Gourguechon, Stéphane; Savich, Jason M.; Ching C Wang

    2007-01-01

    Regulation of eukaryotic cell cycle progression requires sequential activation and inactivation of cyclin-dependent kinases. Previous RNA interference (RNAi) experiments in Trypanosoma brucei indicated that cyclin E1, cdc2-related kinase (CRK)1 and CRK2 are involved in regulating G1/S transition, whereas cyclin B2 and CRK3 play a pivotal role in controlling the G2/M checkpoint. To search for potential interactions between the other cyclins and CRKs that may not have been revealed by the RNAi ...

  7. Differential effects of proton and gamma radiation on gene expression, cell cycle progression and metastatic potential of human non-small cell lung carcinoma cells

    International Nuclear Information System (INIS)

    Proton beam therapy is an emerging mode of cancer radiotherapy due to its excellent dose deposition profile in tumor mass. However, the radiobiological aspects of proton irradiation in comparison with gamma radiation have not been studied in detail. Hence, the present study was aimed to investigate the differential effects of proton and gamma radiation in terms of gene expression, cell cycle progression and metastatic potential at clinically relevant doses. Human lung carcinoma cells (A549) were irradiated with 2 Gy of proton (3 MeV, Average LET= 13 keV/μm) and 2.2 Gy of gamma (equivalent dose for two types of radiation considering RBE value of proton). Microarray analysis of A549 cells 4 hours after proton irradiation showed ∼ ten times higher number of genes that were up or down regulated (at 2-fold) as compared to gamma irradiation. Many of the upregulated genes after proton irradiation were involved in cell cycle arrest and apoptosis, which were further confirmed by quantitative real time PCR. Moreover, flow cytometry results also showed significantly higher and longer cell cycle arrest and increased apoptotic death in proton irradiated cells. Furthermore, in order to investigate whether in comparison to conventional gamma irradiation, proton radiation has any differential effect on metastatic potential of irradiated tumor cells; we looked at adhesion, motility and invasion in irradiated A549 cells. Cells irradiated with proton beam exhibited lower adhesion and motility than that observed with gamma irradiation. In conclusion, our results suggest that two forms of radiation exhibit differential radiobiological response with an advantage of lower metastatic potential in lung cancer cells after proton irradiation. These results provide better understanding of the molecular mechanism(s) of proton radiation in cancer cells, which might be useful in it's better therapeutic applications. (author)

  8. DACH1 regulates cell cycle progression of myeloid cells through the control of cyclin D, Cdk 4/6 and p21{sup Cip1}

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Jae-Woong; Kim, Hyeng-Soo; Kim, Seonggon; Hwang, Junmo; Kim, Young Hun; Lim, Ga Young [School of Life Science and Biotechnology, Kyungpook National University, Daegu 702-701 (Korea, Republic of); Sohn, Wern-Joo [Department of Biochemistry, School of Dentistry, IHBR, Kyungpook National University, Daegu 700-412 (Korea, Republic of); Yoon, Suk-Ran [Cell Therapy Research Center, Korea Research Institute of Bioscience and Biotechnology, Yuseong-gu, Daejeon 305-806 (Korea, Republic of); Kim, Jae-Young [Department of Biochemistry, School of Dentistry, IHBR, Kyungpook National University, Daegu 700-412 (Korea, Republic of); Park, Tae Sung [Department of Laboratory Medicine, Kyung Hee University School of Medicine, 1 Hoegi-dong, Dongdaemun-gu, Seoul 130-702 (Korea, Republic of); Park, Kwon Moo [Department of Anatomy, Kyungpook National University School of Medicine, Daegu 700-422 (Korea, Republic of); Ryoo, Zae Young [School of Life Science and Biotechnology, Kyungpook National University, Daegu 702-701 (Korea, Republic of); Lee, Sanggyu, E-mail: slee@knu.ac.kr [School of Life Science and Biotechnology, Kyungpook National University, Daegu 702-701 (Korea, Republic of)

    2012-03-30

    Highlights: Black-Right-Pointing-Pointer DACH1 increases cyclin D, F and Cdk 1, 4, 6 in mouse myeloid progenitor cells. Black-Right-Pointing-Pointer The knockdown of DACH1 blocked the cell cycle progression of HL-60 cells. Black-Right-Pointing-Pointer The novel effect of DACH1 related with cell cycle regulation and leukemogenesis. -- Abstract: The cell-fate determination factor Dachshund, a component of the Retinal Determination Gene Network (RDGN), has a role in breast tumor proliferation through the repression of cyclin D1 and several key regulators of embryonic stem cell function, such as Nanog and Sox2. However, little is known about the role of DACH1 in a myeloid lineage as a cell cycle regulator. Here, we identified the differential expression levels of extensive cell cycle regulators controlled by DACH1 in myeloid progenitor cells. The forced expression of DACH1 induced p27{sup Kip1} and repressed p21{sup Cip1}, which is a pivotal characteristic of the myeloid progenitor. Furthermore, DACH1 significantly increased the expression of cyclin D1, D3, F, and Cdk 1, 4, and 6 in myeloid progenitor cells. The knockdown of DACH1 blocked the cell cycle progression of HL-60 promyeloblastic cells through the decrease of cyclin D1, D3, F, and Cdk 1, 4, and 6 and increase in p21{sup Cip1}, which in turn decreased the phosphorylation of the Rb protein. The expression of Sox2, Oct4, and Klf4 was significantly up-regulated by the forced expression of DACH1 in mouse myeloid progenitor cells.

  9. DACH1 regulates cell cycle progression of myeloid cells through the control of cyclin D, Cdk 4/6 and p21Cip1

    International Nuclear Information System (INIS)

    Highlights: ► DACH1 increases cyclin D, F and Cdk 1, 4, 6 in mouse myeloid progenitor cells. ► The knockdown of DACH1 blocked the cell cycle progression of HL-60 cells. ► The novel effect of DACH1 related with cell cycle regulation and leukemogenesis. -- Abstract: The cell-fate determination factor Dachshund, a component of the Retinal Determination Gene Network (RDGN), has a role in breast tumor proliferation through the repression of cyclin D1 and several key regulators of embryonic stem cell function, such as Nanog and Sox2. However, little is known about the role of DACH1 in a myeloid lineage as a cell cycle regulator. Here, we identified the differential expression levels of extensive cell cycle regulators controlled by DACH1 in myeloid progenitor cells. The forced expression of DACH1 induced p27Kip1 and repressed p21Cip1, which is a pivotal characteristic of the myeloid progenitor. Furthermore, DACH1 significantly increased the expression of cyclin D1, D3, F, and Cdk 1, 4, and 6 in myeloid progenitor cells. The knockdown of DACH1 blocked the cell cycle progression of HL-60 promyeloblastic cells through the decrease of cyclin D1, D3, F, and Cdk 1, 4, and 6 and increase in p21Cip1, which in turn decreased the phosphorylation of the Rb protein. The expression of Sox2, Oct4, and Klf4 was significantly up-regulated by the forced expression of DACH1 in mouse myeloid progenitor cells.

  10. A novel parameter, cell-cycle progression index, for radiation dose absorbed estimation in the premature chromosome condensation assay

    International Nuclear Information System (INIS)

    The calyculin A-induced premature chromosome condensation (PCC) assay is a simple and useful method for assessing the cell-cycle distribution in cells, since calyculin A induces chromosome condensation in various phases of the cell cycle. In this study, a novel parameter, the cell-cycle progression index (CPI), in the PCC assay was validated as a novel bio-marker for bio-dosimetry. Peripheral blood was drawn from healthy donors after informed consent was obtained. CPI was investigated using a human peripheral blood lymphocyte (PBL) ex vivo irradiation (60Co-gamma rays: ∼0.6 Gy min-1, or X ray: 1.0 Gy min-1; 0-10 Gy) model. The calyculin A-induced PCC assay was performed for chromosome preparation. PCC cells were divided into the following five categories according to cell-cycle stage: non-PCC, G1-PCC, S-PCC, G2/M-PCC and M/A-PCC cells. CPI was calculated as the ratio of G2/M-PCC cells to G1-PCC cells. The PCC-stage distribution varied markedly with irradiation doses. The G1-PCC cell fraction was significantly reduced, and the G2/M-PCC cell fraction increased, in 10-Gy-irradiated PBL after 48 h of culture. CPI levels were fitted to an exponential dose-response curve with gamma-ray irradiation [y = 0.6729 + 0.3934 exp(0.5685D), r = 1.0000, p < 0.0001] and X-ray irradiation [y = -0.3743 + 0.9744 exp(0.3321D), r = 0.9999, p < 0.0001]. There were no significant individual (p = 0.853) or gender effects (p = 0.951) on the CPI in the human peripheral blood ex vivo irradiation model. Furthermore, CPI measurements are rapid (< 15 min per case). These results suggest that the CPI is a useful screening tool for the assessment of radiation doses received ranging from 0 to 10 Gy in radiation exposure early after a radiation event, especially after a mass-casualty radiological incident. (authors)

  11. Drosophila Sld5 is essential for normal cell cycle progression and maintenance of genomic integrity

    International Nuclear Information System (INIS)

    Research highlights: → Drosophila Sld5 interacts with Psf1, PPsf2, and Mcm10. → Haploinsufficiency of Sld5 leads to M-phase delay and genomic instability. → Sld5 is also required for normal S phase progression. -- Abstract: Essential for the normal functioning of a cell is the maintenance of genomic integrity. Failure in this process is often catastrophic for the organism, leading to cell death or mis-proliferation. Central to genomic integrity is the faithful replication of DNA during S phase. The GINS complex has recently come to light as a critical player in DNA replication through stabilization of MCM2-7 and Cdc45 as a member of the CMG complex which is likely responsible for the processivity of helicase activity during S phase. The GINS complex is made up of 4 members in a 1:1:1:1 ratio: Psf1, Psf2, Psf3, And Sld5. Here we present the first analysis of the function of the Sld5 subunit in a multicellular organism. We show that Drosophila Sld5 interacts with Psf1, Psf2, and Mcm10 and that mutations in Sld5 lead to M and S phase delays with chromosomes exhibiting hallmarks of genomic instability.

  12. Fe3 O4 nanoparticle redox system modulation via cell-cycle progression and gene expression in human mesenchymal stem cells.

    Science.gov (United States)

    Periasamy, Vaiyapuri S; Athinarayanan, Jegan; Alhazmi, Mohammad; Alatiah, Khalid A; Alshatwi, Ali A

    2016-08-01

    The use of engineered nanoparticles (NPs) across multiple fields and applications has rapidly increased over the last decade owing to their unusual properties. However, there is an increased need in understanding their toxicological effect on human health. Particularly, iron oxide (Fe3 O4 ) have been used in various sectors, including biomedical, food, and agriculture, but the current understanding of their impact on human health is inadequate. In this investigation, we assessed the toxic effect of Fe3 O4 NPs on human mesenchymal stem cells (hMSCs) adopting cell viability, cellular morphological changes, mitochondrial transmembrane potential, and cell-cycle progression assessment methodologies. Furthermore, the expression of oxidative stress, cell death, and cell-cycle regulatory genes was assessed using quantitative polymerase chain reaction. The Fe3 O4 NPs induced cytotoxicity and nuclear morphological changes in hMSCs by dose and time exposure. Cell-cycle analysis indicated that Fe3 O4 NPs altered the cell-cycle progression through a decrease in the proportion of cells in the G0 -G1 phase. The hMSC mitochondrial membrane potential loss increased with an increase in the concentration of Fe3 O4 NPs exposure. The observed expression levels of the CYP1A, TNF3, TNFSF10, E2F1, and CCNC genes were significantly upregulated in hMSCs in response to Fe3 O4 NPs exposure. Our findings suggest that Fe3 O4 NPs caused metabolic stress through altered cell cycle, oxidative stress, and cell death regulatory gene expression in hMSCs. The results of this investigation revealed that Fe3 O4 NPs exhibited moderate toxicity on hMSCs and that Fe3 O4 NPs may have biomedical applications at low concentrations. © 2014 Wiley Periodicals, Inc. Environ Toxicol 31: 901-912, 2016. PMID:25532727

  13. In silico design and biological evaluation of a dual specificity kinase inhibitor targeting cell cycle progression and angiogenesis.

    Directory of Open Access Journals (Sweden)

    Antony M Latham

    Full Text Available Protein kinases play a central role in tumor progression, regulating fundamental processes such as angiogenesis, proliferation and metastasis. Such enzymes are an increasingly important class of drug target with small molecule kinase inhibitors being a major focus in drug development. However, balancing drug specificity and efficacy is problematic with off-target effects and toxicity issues.We have utilized a rational in silico-based approach to demonstrate the design and study of a novel compound that acts as a dual inhibitor of vascular endothelial growth factor receptor 2 (VEGFR2 and cyclin-dependent kinase 1 (CDK1. This compound acts by simultaneously inhibiting pro-angiogenic signal transduction and cell cycle progression in primary endothelial cells. JK-31 displays potent in vitro activity against recombinant VEGFR2 and CDK1/cyclin B proteins comparable to previously characterized inhibitors. Dual inhibition of the vascular endothelial growth factor A (VEGF-A-mediated signaling response and CDK1-mediated mitotic entry elicits anti-angiogenic activity both in an endothelial-fibroblast co-culture model and a murine ex vivo model of angiogenesis.We deduce that JK-31 reduces the growth of both human endothelial cells and human breast cancer cells in vitro. This novel synthetic molecule has broad implications for development of similar multi-kinase inhibitors with anti-angiogenic and anti-cancer properties. In silico design is an attractive and innovative method to aid such drug discovery.

  14. Drosophila Ctf4 is essential for efficient DNA replication and normal cell cycle progression

    Directory of Open Access Journals (Sweden)

    Christensen Tim W

    2011-04-01

    Full Text Available Abstract Background Proper coordination of the functions at the DNA replication fork is vital to the normal functioning of a cell. Specifically the precise coordination of helicase and polymerase activity is crucial for efficient passage though S phase. The Ctf4 protein has been shown to be a central member of the replication fork and links the replicative MCM helicase and DNA polymerase α primase. In addition, it has been implicated as a member of a complex that promotes replication fork stability, the Fork Protection Complex (FPC, and as being important for sister chromatid cohesion. As such, understanding the role of Ctf4 within the context of a multicellular organism will be integral to our understanding of its potential role in developmental and disease processes. Results We find that Drosophila Ctf4 is a conserved protein that interacts with members of the GINS complex, Mcm2, and Polymerase α primase. Using in vivo RNAi knockdown of CTF4 in Drosophila we show that Ctf4 is required for viability, S phase progression, sister chromatid cohesion, endoreplication, and coping with replication stress. Conclusions Ctf4 remains a central player in DNA replication. Our findings are consistent with what has been previously reported for CTF4 function in yeast, Xenopus extracts, and human tissue culture. We show that Ctf4 function is conserved and that Drosophila can be effectively used as a model to further probe the precise function of Ctf4 as a member of the replication fork and possible roles in development.

  15. RalGPS2 Is Essential for Survival and Cell Cycle Progression of Lung Cancer Cells Independently of Its Established Substrates Ral GTPases.

    Directory of Open Access Journals (Sweden)

    Adriana O Santos

    Full Text Available The human genome contains six genes coding for proteins validated in vitro as specific activators of the small GTPases "Ras-related protein Ral-A" and "Ras-related protein Ral-B", generically named Ral-guanine nucleotide exchange factors (RalGEF. Ral proteins are important contributors to Ras oncogenic signaling, and RAS oncogenes are important in human Non-Small Cell Lung Carcinoma (NSCLC. Therefore in this work, RalGEF contribution to oncogenic and non-oncogenic features of human NSCLC cell lines, as anchorage-dependent and independent growth, cell survival, and proliferation, was investigated. Among all human RalGEF, silencing of RGL1 and RALGPS1 had no detectable effect. However, silencing of either RGL2, RGL3, RALGDS or, to a larger extent, RALGPS2 inhibited cell population growth in anchorage dependent and independent conditions (up to 90 and 80%, respectively. RALGPS2 silencing also caused an increase in the number of apoptotic cells, up to 45% of the cell population in transformed bronchial BZR cells. In H1299 and A549, two NSCLC cell lines, RALGPS2 silencing caused an arrest of cells in the G0/G1-phase of cell cycle. Furthermore, it was associated with the modulation of important cell cycle regulators: the E3 Ubiquitin Protein Ligase S-phase kinase-associated protein 2 (Skp2 was strongly down-regulated (both at mRNA and protein levels, and its targets, the cell cycle inhibitors p27 and p21, were up-regulated. These molecular effects were not mimicked by silencing RALA, RALB, or both. However, RALB silencing caused a modest inhibition of cell cycle progression, which in H1299 cells was associated with Cyclin D1 regulation. In conclusion, RALGPS2 is implicated in the control of cell cycle progression and survival in the in vitro growth of NSCLC cell lines. This function is largely independent of Ral GTPases and associated with modulation of Skp2, p27 and p21 cell cycle regulators.

  16. Effects of 3-aminobenzamide on poly(ADP-ribose)polymerase expression,apoptosis and cell cycle progression of HeLa cells after X-ray irradiation

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    The aim of this paper is to study the changes of apoptosis and cell cycle progression in HeLa cells after the poly(ADP-ribose)polymerase(PARP)was inhibited by its inhibitor 3-aminobenzamide(3-AB)and the mechanisms of PARP action on HeLa cells damaged by irradiation.Flow cytometry(FCM)was used to examine the PARP expression and the percentage of apoptotic cells and cell cycle progression.The percentage of HeLa cells with positive expression of PARP protein 2,4,8 and 12 h after administrated with 3-AB was significantly lower than that of the control(P<0.01).The percentages of apoptotic cells in the 3-AB plus irradiation group at the time points of 2,8,12 and 24 h after 2 Gy irradiation were higher than that in the irradiation group(P<0.01 or P<0.05)and the percentage of G2 cells decreased significantly(P<0.01 or P<0.05).It indicates that 3-AB can rapidly inhibit PARP expression of HeLa cells,promote cell apoptosis and block G2 arrest induced by irradiation.

  17. Modulation of Cell Cycle Progression by 5-Azacytidine Is Associated with Early Myogenesis Induction in Murine Myoblasts

    Science.gov (United States)

    Montesano, Anna; Luzi, Livio; Senesi, Pamela; Terruzzi, Ileana

    2013-01-01

    expression of Myf-5 (FC: 1.57 GMAZA vs GM p≤0.05), MyoD (FC: 1.14 DM vs GM p≤0.05; FC: 1.47 DMAZA vs GM p≤0.05), p21 (FC: 1.36 GMAZA vs GM p≤0.01; FC: 1.49 DM vs GM p≤0.05; FC: 1.82 DMAZA vs GM p≤0.01) and MyHC (FC: 1.40 GMAZA vs GM p≤0.01; FC: 2.39 DM vs GM p≤0.05; FC: 3.51 DMAZA vs GM p≤0.01). Our results suggest that AZA-induced DNA demethylation can modulate cell cycle progression and enhance myogenesis. The effects of AZA may open novel clinical uses in the field of muscle injury research and treatment. PMID:23678289

  18. Modulation of cell cycle progression by 5-azacytidine is associated with early myogenesis induction in murine myoblasts.

    Science.gov (United States)

    Montesano, Anna; Luzi, Livio; Senesi, Pamela; Terruzzi, Ileana

    2013-01-01

    expression of Myf-5 (FC: 1.57 GMAZA vs GM p≤0.05), MyoD (FC: 1.14 DM vs GM p≤0.05; FC: 1.47 DMAZA vs GM p≤0.05), p21 (FC: 1.36 GMAZA vs GM p≤0.01; FC: 1.49 DM vs GM p≤0.05; FC: 1.82 DMAZA vs GM p≤0.01) and MyHC (FC: 1.40 GMAZA vs GM p≤0.01; FC: 2.39 DM vs GM p≤0.05; FC: 3.51 DMAZA vs GM p≤0.01). Our results suggest that AZA-induced DNA demethylation can modulate cell cycle progression and enhance myogenesis. The effects of AZA may open novel clinical uses in the field of muscle injury research and treatment. PMID:23678289

  19. Overexpression of cell cycle regulator CDCA3 promotes oral cancer progression by enhancing cell proliferation with prevention of G1 phase arrest

    International Nuclear Information System (INIS)

    Cell division cycle associated 3 (CDCA3), part of the Skp1-cullin-F-box (SCF) ubiquitin ligase, refers to a trigger of mitotic entry and mediates destruction of the mitosis inhibitory kinase. Little is known about the relevance of CDCA3 to human malignancy including oral squamous cell carcinoma (OSCC). We aimed to characterize the expression state and function of CDCA3 in OSCC. We evaluated CDCA3 mRNA and protein expression in both OSCC-derived cell lines and primary OSCCs and performed functional analyses of CDCA3 in OSCC-derived cells using the shRNA system. The CDCA3 expression at both the mRNA and protein levels was frequently up-regulated in all cell lines examined and primary tumors (mRNA, 51/69, 74 %; protein, 79/95, 83 %) compared to normal controls (p < 0.001). In contrast, no significant level of CDCA3 protein expression was seen in oral premalignant lesions (OPLs) (n = 20) compared with the expression in OSCCs. Among the clinical variables analyzed, the CDCA3 expression status was closely related to tumor size (p < 0.05). In addition, suppression of CDCA3 expression with shRNA significantly (p < 0.05) inhibited cellular proliferation compared with the control cells by arresting cell-cycle progression at the G1 phase. Further, there was up-regulation of the cyclin-dependent kinase inhibitors (p21Cip1, p27Kip1, p15INK4B, and p16INK4A) in the knockdown cells. The current results showed that overexpression of CDCA3 occurs frequently during oral carcinogenesis and this overexpression might be associated closely with progression of OSCCs by preventing the arrest of cell-cycle progression at the G1 phase via decreased expression of the cyclin-dependent kinase inhibitors

  20. Induction of cell cycle progression by adenovirus E1A gene 13S- and 12S-mRNA products in quiescent rat cells.

    OpenAIRE

    Nakajima, T.; Masuda-Murata, M; Hara, E; Oda, K.

    1987-01-01

    Rat 3Y1 cell lines that express either adenovirus type 12 E1A 13S mRNA or 12S mRNA in response to dexamethasone treatment were established by introduction of recombinant vector DNA containing the E1A 13S- or 12S-mRNA cDNA placed downstream of the hormone-inducible promoter of mouse mammary tumor virus. These cell lines were growth arrested, and the induction of cell cycle progression was analyzed by flow cytometry after switch on of the cDNA by the addition of dexamethasone. The results indic...

  1. Epidermal growth factor-mediated T-cell factor/lymphoid enhancer factor transcriptional activity is essential but not sufficient for cell cycle progression in nontransformed mammary epithelial cells

    OpenAIRE

    Graham, Nicholas A.; Asthagiri, Anand R.

    2004-01-01

    Because beta-catenin target genes such as cyclin D1 are involved in cell cycle progression, we examined whether beta-catenin has a more pervasive role in normal cell proliferation, even upon stimulation by non-Wnt ligands. Here, we demonstrate that epidermal growth factor (EGF) stimulates T-cell factor/lymphoid enhancer factor (Tcf/Lef) transcriptional activity in nontransformed mammary epithelial cells (MCF-10A) and that its transcriptional activity is essential for EGF-mediated progression ...

  2. Effects of the radioprotector WR-1065 on aspects of DNA metabolism and cell cycle progression in CHO AA8 and human HSF4 cells

    International Nuclear Information System (INIS)

    The radioprotector WR-1065 (2-[(aminopropyl) amino]ethanethiol) is known to protect mammalian cells from the cytotoxic and mutagenic effects of radiation exposure, but the exact mechanisms involved in this protection are not fully known. The effect of WR-1065 on a variety of cellular processes in two cell lines was examined to determine how it may provide protection. Incubation of Chinese hamster ovary AA8 cells in 4 mM WR-1065 did not significantly affect the DNA synthetic rate. Autoradiographic analysis of heavily labeled nuclei of AA8 cells showed no significant difference in the size of the S phase population of WR-1065 treated versus control cells for up to 3 h. An examination of the effect of WR-1065 on repair synthesis, as measured by unscheduled DNA synthesis (UDS) in cells exposed to 15 Gy of gamma-rays, showed no difference between treated and sham treated cells for up to 2 h exposure time. A significant reduction in the amount of UDS was seen in cells treated with the protector for 2.5 and 3h. WR-1065 concentrations ranging from 0.5 mM to 4 mM were not cytotoxic to normal human skin fibroblast cells (HSF4) for exposure to 137Cs gamma-rays resulted in a protection factor of 3.5, almost twice that observed for AA8 cells with 4 mM Wr-1065. Growth of AA8 cells in either alpha-minimal essential medium or McCoy's 5 a medium did not affect the alteration in cell cycle progression observed. These data suggest that perturbations in cell cycle progression, rather than direct effects on the rate of DNA synthesis, could play a role in the increased survival and reduced mutation frequencies observed in the presence of WR-1065 by allowing more time for the repair of DNA damage prior to division

  3. S100A8/A9 (calprotectin negatively regulates G2/M cell cycle progression and growth of squamous cell carcinoma.

    Directory of Open Access Journals (Sweden)

    Ali Khammanivong

    Full Text Available Malignant transformation results in abnormal cell cycle regulation and uncontrolled growth in head and neck squamous cell carcinoma (HNSCC and other cancers. S100A8/A9 (calprotectin is a calcium-binding heterodimeric protein complex implicated in cell cycle regulation, but the specific mechanism and role in cell cycle control and carcinoma growth are not well understood. In HNSCC, S100A8/A9 is downregulated at both mRNA and protein levels. We now report that downregulation of S100A8/A9 correlates strongly with a loss of cell cycle control and increased growth of carcinoma cells. To show its role in carcinogenesis in an in vitro model, S100A8/A9 was stably expressed in an S100A8/A9-negative human carcinoma cell line (KB cells, HeLa-like. S100A8/A9 expression increases PP2A phosphatase activity and p-Chk1 (Ser345 phosphorylation, which appears to signal inhibitory phosphorylation of mitotic p-Cdc25C (Ser216 and p-Cdc2 (Thr14/Tyr15 to inactivate the G2/M Cdc2/cyclin B1 complex. Cyclin B1 expression then downregulates and the cell cycle arrests at the G2/M checkpoint, reducing cell division. As expected, S100A8/A9-expressing cells show both decreased anchorage-dependent and -independent growth and mitotic progression. Using shRNA, silencing of S100A8/A9 expression in the TR146 human HNSCC cell line increases growth and survival and reduces Cdc2 inhibitory phosphorylation at Thr14/Tyr15. The level of S100A8/A9 endogenous expression correlates strongly with the reduced p-Cdc2 (Thr14/Tyr14 level in HNSCC cell lines, SCC-58, OSCC-3 and UMSCC-17B. S100A8/A9-mediated control of the G2/M cell cycle checkpoint is, therefore, a likely suppressive mechanism in human squamous cell carcinomas and may suggest new therapeutic approaches.

  4. The effects of over-expressing Tip60 on cellular DNA damage repair and cell cycle progression

    International Nuclear Information System (INIS)

    To investigate the effects of Tip60 on DNA damage repair, cell cycle and the related mechanism as well, the proliferative activity, DNA double strand break (DSB) repair competency and cell cycle arrest were analyzed in stable Tip60-overexpression U2OS cells established by transfecting with exogenous Tip60 gene. It was found that the overexpression of Tip60 inhibited the proliferative activity but increased the DNA damage repair competency. The radiation-induced G2/M arrest was prolonged in Tip60 over-expressed U2OS cells, which was associated with a decreasing level of cell cycle checkpoint protein Cyclin B/CDC2 complex. (authors)

  5. Time-effect of adaptive response of mouse thymocyte apoptosis and cell cycle progression induced by low dose radiation

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    目的:观察低剂量辐射(LDR)诱导胸腺细胞凋亡及细胞周期进程适应性反应的基本规律。方法:用X射线照射昆明系雄性小鼠,其诱导剂量(D1)及其后攻击剂量(D2)分别是75 mGy 和1.5 Gy。D1和D2间隔时间分别是3、6、12、24和60 h。D2照射后18 h胸腺细胞培养4、20 和44 h用流式细胞仪检测胸腺细胞凋亡小体(TAB)和细胞周期进程的变化。结果:当D1和D2间隔3、6和12 h,在D2照射后胸腺细胞培养4和20 h,D1 + D2组 TAB 百分数明显低于D2组(P<0.05),G0/G1和G2+M期细胞百分数也不同程度地低于D2组, 而S期细胞百分数却明显高于D2组(P<0.05或P<0.01)。结论:D1和D2分别是75 mGy(剂量率,12.5 mGy/min)和1.5 Gy(剂量率,0.287 Gy/min),D1和D2间隔3~12 h, 在小鼠全身照射后其胸腺细胞培养4和20 h可诱导细胞凋亡和细胞周期进程的适应性反应。%Objective: In the present study we observed the general pattern of the adaptive response of thymocyte apoptosis and cell cycle progression induced by low dose radiation (LDR). Methods: Kunming male mice were irradiated with the inductive dose (D1, 75 mGy) and the challenging dose (D2, 1.5 Gy). The intervals between D1 and D2 were 3, 6, 12, 24 and 60 hours. The changes of thymocyte apoptotic bodies (TAB) and cell cycle progression were measured with flow cytometry with the thymocytes cultured for 4, 20 and 44 hours, respectively, 18 hours after irradiation with D2. Results: When the intervals between D1 and D2 were 3, 6 and 12 hours, the percentages of TAB in the D1 + D2 groups in the thymocytes cultured for 4 and 20 hours were significantly lower than those in the D2 groups (P<0.05) and the percentages of G0/G1 and G2 + M phase cells decreased in varying degrees, while the percentages of S phase cells increased significantly (P<0.05 or P<0.01). Conclusion: The results mentioned above indicate that when the mice were irradiated with 75 m

  6. Histone deacetylase inhibitors SAHA and sodium butyrate block G1-to-S cell cycle progression in neurosphere formation by adult subventricular cells

    Directory of Open Access Journals (Sweden)

    Doughty Martin L

    2011-05-01

    Full Text Available Abstract Background Histone deacetylases (HDACs are enzymes that modulate gene expression and cellular processes by deacetylating histones and non-histone proteins. While small molecule inhibitors of HDAC activity (HDACi are used clinically in the treatment of cancer, pre-clinical treatment models suggest they also exert neuroprotective effects and stimulate neurogenesis in neuropathological conditions. However, the direct effects of HDACi on cell cycle progression and proliferation, two properties required for continued neurogenesis, have not been fully characterized in adult neural stem cells (NSCs. In this study, we examined the effects of two broad class I and class II HDACi on adult mouse NSCs, the hydroxamate-based HDACi suberoylanilide hydroxamic acid (vorinostat, SAHA and the short chain fatty acid HDACi sodium butyrate. Results We show that both HDACi suppress the formation of neurospheres by adult mouse NSCs grown in proliferation culture conditions in vitro. DNA synthesis is significantly inhibited in adult mouse NSCs exposed to either SAHA or sodium butyrate and inhibition is associated with an arrest in the G1 phase of the cell cycle. HDACi exposure also resulted in transcriptional changes in adult mouse NSCs. Cdk inhibitor genes p21 and p27 transcript levels are increased and associated with elevated H3K9 acetylation levels at proximal promoter regions of p21 and p27. mRNA levels for notch effector Hes genes and Spry-box stem cell transcription factors are downregulated, whereas pro-neural transcription factors Neurog1 and Neurod1 are upregulated. Lastly, we show HDAC inhibition under proliferation culture conditions leads to long-term changes in cell fate in adult mouse NSCs induced to differentiate in vitro. Conclusion SAHA and sodium butyrate directly regulate cdk inhibitor transcription to control cell cycle progression in adult mouse NSCs. HDAC inhibition results in G1 arrest in adult mouse NSCs and transcriptional changes

  7. The multiple roles of cyclin E1 in controlling cell cycle progression and cellular morphology of Trypanosoma brucei.

    Science.gov (United States)

    Gourguechon, Stéphane; Savich, Jason M; Wang, Ching C

    2007-05-11

    Regulation of eukaryotic cell cycle progression requires sequential activation and inactivation of cyclin-dependent kinases. Previous RNA interference (RNAi) experiments in Trypanosoma brucei indicated that cyclin E1, cdc2-related kinase (CRK)1 and CRK2 are involved in regulating G1/S transition, whereas cyclin B2 and CRK3 play a pivotal role in controlling the G2/M checkpoint. To search for potential interactions between the other cyclins and CRKs that may not have been revealed by the RNAi assays, we used the yeast two-hybrid system and an in vitro glutathione-S-transferase pulldown assay and observed interactions between cyclin E1 and CRK1, CRK2 and CRK3. Cyclins E1-E4 are homologues of yeast Pho80 cyclin. But yeast complementation assays indicated that none of them possesses a Pho80-like function. Analysis of cyclin E1+CRK1 and cyclin E1+CRK2 double knockdowns in the procyclic form of T. brucei indicated that the cells were arrested more extensively in the G1 phase beyond the cumulative effect of individual knockdowns. But BrdU incorporation was impaired significantly only in cyclin E1+CRK1-depleted cells, whereas a higher percentage of cyclin E1+CRK2 knockdown cells assumed a grossly elongated posterior end morphology. A double knockdown of cyclin E1 and CRK3 arrested cells in G2/M much more efficiently than if only CRK3 was depleted. Taken together, these data suggest multiple functions of cyclin E1: it forms a complex with CRK1 in promoting G1/S phase transition; it forms a complex with CRK2 in controlling the posterior morphogenesis during G1/S transition; and it forms a complex with CRK3 in promoting passage across the G2/M checkpoint in the trypanosome. PMID:17376478

  8. EIF3 p170, a Mediator of Mimosine Effect on Protein Synthesis and Cell Cycle Progression

    OpenAIRE

    Dong, Zizheng; Zhang, Jian-Ting

    2003-01-01

    l-Mimosine, a plant amino acid, can reversibly block mammalian cells at late G1 phase and has been suggested to affect translation of mRNAs such as p27, the CDK inhibitor. However, the mechanism of this effect is not known. Regulation of translation generally occurs at the initiation step that, in mammalian cells, is a complex process that requires multiple eukaryotic initiation factors (eIFs) and ribosome. The effects of mimosine on initiation factors or regulators consequently will influenc...

  9. The "Yin" and "Yang" of Cell Cycle Progression and Differentiation in the Oligodendroglial Lineage

    Science.gov (United States)

    Nguyen, Laurent; Borgs, Laurence; Vandenbosch, Renaud; Mangin, Jean-Marie; Beukelaers, Pierre; Moonen, Gustave; Gallo, Vittorio; Malgrange, Brigitte; Belachew, Shibeshih

    2006-01-01

    In white matter disorders such as leukodystrophies (LD), periventricular leucomalacia (PVL), or multiple sclerosis (MS), the hypomyelination or the remyelination failure by oligodendrocyte progenitor cells involves errors in the sequence of events that normally occur during development when progenitors proliferate, migrate through the white…

  10. NPAT expression is regulated by E2F and is essential for cell cycle progression

    DEFF Research Database (Denmark)

    Gao, Guang; Bracken, Adrian P; Burkard, Karina;

    2003-01-01

    NPAT is an in vivo substrate of cyclin E-Cdk2 kinase and is thought to play a critical role in coordinated transcriptional activation of histone genes during the G(1)/S-phase transition and in S-phase entry in mammalian cells. Here we show that NPAT transcription is up-regulated at the G(1)/S-pha...

  11. Glucosylceramide synthesis inhibition affects cell cycle progression, membrane trafficking, and stage differentiation in Giardia lamblia[S

    Science.gov (United States)

    Štefanić, Saša; Spycher, Cornelia; Morf, Laura; Fabriàs, Gemma; Casas, Josefina; Schraner, Elisabeth; Wild, Peter; Hehl, Adrian B.; Sonda, Sabrina

    2010-01-01

    Synthesis of glucosylceramide via glucosylceramide synthase (GCS) is a crucial event in higher eukaryotes, both for the production of complex glycosphingolipids and for regulating cellular levels of ceramide, a potent antiproliferative second messenger. In this study, we explored the dependence of the early branching eukaryote Giardia lamblia on GCS activity. Biochemical analyses revealed that the parasite has a GCS located in endoplasmic reticulum (ER) membranes that is active in proliferating and encysting trophozoites. Pharmacological inhibition of GCS induced aberrant cell division, characterized by arrest of cytokinesis, incomplete cleavage furrow formation, and consequent block of replication. Importantly, we showed that increased ceramide levels were responsible for the cytokinesis arrest. In addition, GCS inhibition resulted in prominent ultrastructural abnormalities, including accumulation of cytosolic vesicles, enlarged lysosomes, and clathrin disorganization. Moreover, anterograde trafficking of the encystations-specific protein CWP1 was severely compromised and resulted in inhibition of stage differentiation. Our results reveal novel aspects of lipid metabolism in G. lamblia and specifically highlight the vital role of GCS in regulating cell cycle progression, membrane trafficking events, and stage differentiation in this parasite. In addition, we identified ceramide as a potent bioactive molecule, underscoring the universal conservation of ceramide signaling in eukaryotes. PMID:20335568

  12. The retinoblastoma-susceptibility gene product becomes phosphorylated in multiple stages during cell cycle entry and progression.

    OpenAIRE

    DeCaprio, J A; Furukawa, Y.; Ajchenbaum, F; Griffin, J D; Livingston, D M

    1992-01-01

    The retinoblastoma-susceptibility gene product (RB) undergoes cell cycle-dependent phosphorylation and dephosphorylation. We characterized RB phosphorylation after mitogenic stimulation of primary human T lymphocytes, initially arrested in the G0 state. RB is phosphorylated in at least three steps when T cells are driven into the cell cycle. The first event occurs during mid G1 phase, the second during S phase, and the third in G2/M. Tryptic phosphopeptide mapping indicates that the different...

  13. PKM2 uses control of HuR localization to regulate p27 and cell cycle progression in human glioblastoma cells.

    Science.gov (United States)

    Mukherjee, Joydeep; Ohba, Shigeo; See, Wendy L; Phillips, Joanna J; Molinaro, Annette M; Pieper, Russell O

    2016-07-01

    The M2 isoform of pyruvate kinase (PK) is upregulated in most cancers including glioblastoma. Although PKM2 has been reported to use dual kinase activities to regulate cell growth, it also interacts with phosphotyrosine (pY)-containing peptides independently of its kinase activity. The potential for PKM2 to use the binding of pY-containing proteins to control tumor growth has not been fully examined. We here describe a novel mechanism by which PKM2 interacts in the nucleus with the RNA binding protein HuR to regulate HuR sub-cellular localization, p27 levels, cell cycle progression and glioma cell growth. Suppression of PKM2 in U87, T98G and LN319 glioma cells resulted in increased p27 levels, defects in entry into mitosis, increased centrosome number, and decreased cell growth. These effects could be reversed by shRNA targeting p27. The increased levels of p27 in PKM2 knock-down cells were caused by a loss of the nuclear interaction between PKM2 and HuR, and a subsequent cytoplasmic re-distribution of HuR, which in turn led to increased cap-independent p27 mRNA translation. Consistent with these results, the alterations in p27 mRNA translation, cell cycle progression and cell growth caused by PKM2 suppression could be reversed in vitro and in vivo by suppression of HuR or p27 levels, or by introduction of forms of PKM2 that could bind pY, regardless of their kinase activity. These results define a novel mechanism by which PKM2 regulates glioma cell growth, and also define a novel set of potential therapeutic targets along the PKM2-HuR-p27 pathway. PMID:26874904

  14. Drosophila Ctf4 is essential for efficient DNA replication and normal cell cycle progression

    OpenAIRE

    Christensen Tim W; Gosnell Justin A

    2011-01-01

    Abstract Background Proper coordination of the functions at the DNA replication fork is vital to the normal functioning of a cell. Specifically the precise coordination of helicase and polymerase activity is crucial for efficient passage though S phase. The Ctf4 protein has been shown to be a central member of the replication fork and links the replicative MCM helicase and DNA polymerase α primase. In addition, it has been implicated as a member of a complex that promotes replication fork sta...

  15. A rapid and robust assay for detection of S-phase cell cycle progression in plant cells and tissues by using ethynyl deoxyuridine

    Directory of Open Access Journals (Sweden)

    Horváth Gábor V

    2010-01-01

    Full Text Available Abstract Background Progress in plant cell cycle research is highly dependent on reliable methods for detection of cells replicating DNA. Frequency of S-phase cells (cells in DNA synthesis phase is a basic parameter in studies on the control of cell division cycle and the developmental events of plant cells. Here we extend the microscopy and flow cytometry applications of the recently developed EdU (5-ethynyl-2'-deoxyuridine-based S-phase assay to various plant species and tissues. We demonstrate that the presented protocols insure the improved preservation of cell and tissue structure and allow significant reduction in assay duration. In comparison with the frequently used detection of bromodeoxyuridine (BrdU and tritiated-thymidine incorporation, this new methodology offers several advantages as we discuss here. Results Applications of EdU-based S-phase assay in microscopy and flow cytometry are presented by using cultured cells of alfalfa, Arabidopsis, grape, maize, rice and tobacco. We present the advantages of EdU assay as compared to BrdU-based replication assay and demonstrate that EdU assay -which does not require plant cell wall digestion or DNA denaturation steps, offers reduced assay duration and better preservation of cellular, nuclear and chromosomal morphologies. We have also shown that fast and efficient EdU assay can also be an efficient tool for dual parameter flow cytometry analysis and for quantitative assessment of replication in thick root samples of rice. Conclusions In plant cell cycle studies, EdU-based S-phase detection offers a superior alternative to the existing S-phase assays. EdU method is reliable, versatile, fast, simple and non-radioactive and it can be readily applied to many different plant systems.

  16. Characterisation of the histone methyltransferase SET8 in cell cycle progression and the DNA damage response

    DEFF Research Database (Denmark)

    Jørgensen, Stine

    2008-01-01

    recombination and repair. I therefore initiated a mass spectrometry based study to identify changes in histone modifications after DNA damage. By using SILAC labelling of cells to quantatively measure the changes in histone modifications, we observed a marked reduction in the level of monomethylated Histone H4...... of DNA double strand breaks (DSBs) and activation of CHK1, an important mediator of the S phase checkpoint. Furthermore, we demonstrated that the generation of DSBs, seen upon depletion of SET8, was dependent on replication. Additionally, we identified an interaction between SET8 and PCNA, a key...

  17. Effect of Procyanidin-rich Extract from Natural Cocoa Powder on Cellular Viability, Cell Cycle Progression, and Chemoresistance in Human Epithelial Ovarian Carcinoma Cell Lines

    Science.gov (United States)

    Taparia, Shruti; Khanna, Aparna

    2016-01-01

    cocoa powder is one of the richest sources of procyanidinsCocoa procyanidin-rich extract (CPRE) caused cytotoxicity and chemosensitization in ovarian carcinoma cell lines OAW42 and OVCAR3CPRE affected normal cell cycle progressionCPRE also downregulated P-glycoprotein, which mediates chemoresistance in multidrug-resistant OVCAR3 cell line. Abbreviations used: P-gp: P-glycoprotein, CPRE: Cocoa procyanidin rich extract, DMAC: 4-dimethylaminocinnamaldehyde, DPPH: Diphenylpicrylhydrazyl, ABTS: 2,2’;-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid), PI: Propidium iodide, FITC: Fluorescein isothiocyanate, MTT: 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide, TLC: Thin layer chromatography, HPTLC: High-performance thin layer chromatography. PMID:27279694

  18. Ceramide 1-phosphate induces neointimal formation via cell proliferation and cell cycle progression upstream of ERK1/2 in vascular smooth muscle cells

    International Nuclear Information System (INIS)

    Ceramide 1-phosphate (C1P) is a novel bioactive sphingolipid formed by ceramide kinase (CERK)-catalyzed phosphorylation of ceramide. It has been implicated in the regulation of such vital pathophysiological functions as phagocytosis and inflammation, but there have been no reports ascribing a biological function to CERK in vascular disorders. Here the potential role of CERK/C1P in neointimal formation was investigated using rat aortic vascular smooth muscle cells (VSMCs) in primary culture and a rat carotid injury model. Exogenous C8-C1P stimulated cell proliferation, DNA synthesis, and cell cycle progression of rat aortic VSMCs in primary culture. In addition, wild-type CERK-transfected rat aortic VSMCs induced a marked increase in rat aortic VSMC proliferation and [3H]-thymidine incorporation when compared to empty vector transfectant. C8-C1P markedly activated extracellular signal-regulated kinase 1 and 2 (ERK1/2) within 5 min, and the activation could be prevented by U0126, a MEK inhibitor. Also, K1, a CERK inhibitor, decreased the ERK1/2 phosphorylation and cell proliferation on platelet-derived growth factor (PDGF)-stimulated rat aortic VSMCs. CERK expression and C1P levels were found to be potently increased during neointimal formation using a rat carotid injury model. However, ceramide levels decreased during the neointimal formation process. These findings suggest that C1P can induce neointimal formation via cell proliferation through the regulation of the ERK1/2 protein in rat aortic VSMCs and that CERK/C1P may regulate VSMC proliferation as an important pathogenic marker in the development of cardiovascular disorders.

  19. Ceramide 1-phosphate induces neointimal formation via cell proliferation and cell cycle progression upstream of ERK1/2 in vascular smooth muscle cells

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Tack-Joong, E-mail: ktj@yonsei.ac.kr [Division of Biological Science and Technology, College of Science and Technology, Yonsei University, Wonju 220-710 (Korea, Republic of); Kang, Yeo-Jin [Division of Biological Science and Technology, College of Science and Technology, Yonsei University, Wonju 220-710 (Korea, Republic of); Lim, Yong [College of Pharmacy, Chungbuk National University, Cheongju 361-763 (Korea, Republic of); Lee, Hyoung-Woo [Division of Biological Science and Technology, College of Science and Technology, Yonsei University, Wonju 220-710 (Korea, Republic of); College of Pharmacy, Chungbuk National University, Cheongju 361-763 (Korea, Republic of); Bae, Kiho [Division of Biological Science and Technology, College of Science and Technology, Yonsei University, Wonju 220-710 (Korea, Republic of); Lee, Youn-Sun; Yoo, Jae-Myung; Yoo, Hwan-Soo; Yun, Yeo-Pyo [College of Pharmacy, Chungbuk National University, Cheongju 361-763 (Korea, Republic of)

    2011-08-15

    Ceramide 1-phosphate (C1P) is a novel bioactive sphingolipid formed by ceramide kinase (CERK)-catalyzed phosphorylation of ceramide. It has been implicated in the regulation of such vital pathophysiological functions as phagocytosis and inflammation, but there have been no reports ascribing a biological function to CERK in vascular disorders. Here the potential role of CERK/C1P in neointimal formation was investigated using rat aortic vascular smooth muscle cells (VSMCs) in primary culture and a rat carotid injury model. Exogenous C8-C1P stimulated cell proliferation, DNA synthesis, and cell cycle progression of rat aortic VSMCs in primary culture. In addition, wild-type CERK-transfected rat aortic VSMCs induced a marked increase in rat aortic VSMC proliferation and [{sup 3}H]-thymidine incorporation when compared to empty vector transfectant. C8-C1P markedly activated extracellular signal-regulated kinase 1 and 2 (ERK1/2) within 5 min, and the activation could be prevented by U0126, a MEK inhibitor. Also, K1, a CERK inhibitor, decreased the ERK1/2 phosphorylation and cell proliferation on platelet-derived growth factor (PDGF)-stimulated rat aortic VSMCs. CERK expression and C1P levels were found to be potently increased during neointimal formation using a rat carotid injury model. However, ceramide levels decreased during the neointimal formation process. These findings suggest that C1P can induce neointimal formation via cell proliferation through the regulation of the ERK1/2 protein in rat aortic VSMCs and that CERK/C1P may regulate VSMC proliferation as an important pathogenic marker in the development of cardiovascular disorders.

  20. N-glycosylation at Asn residues 554 and 566 of E-cadherin affects cell cycle progression through extracellular signal-regulated protein kinase signaling pathway

    Institute of Scientific and Technical Information of China (English)

    Hongbo Zhao; Xiliang Zha; Lidong Sun; Liying Wang; Zhibin Xu; Feng Zhou; Jianmin Su; Jiawei Jin; Yong Yang; Yali Hu

    2008-01-01

    E-cadherin, which has a widely acknowledged role in mediating calcium-dependent cell-cell adhesion between epithelial cells, also functions as a tumor suppressor. The ectodomain of human E-cadherin contains four potential N-glycosylation sites at Asn residues 554, 566, 618, and 633.We investigated the role of E-cadherin N-glycosylation in cell cycle progression by site-directed mutagenesis. We showed previously that all four potential N-glycosylation sites of E-cadherin were N-glycosylated in human breast carcinoma MDA-MB-435 cells. Removal of N-glycan at Asn633 dramatically affected E-cadherin stability. In this study we showed that E-cadherin mutant missing N-glycans at Asn554, Asn566 and Asn618 failed to induce cell cycle arrest in G1 phase and to suppress cell proliferation in comparison with wild-type E-cadherin. Moreover, N-glycans at Asn554 and Asn566, but not at Asn618, seemed to be indispensable for E-cadherin-mediated suppression of cell cycle progression.Removal of N-glycans at either Asn554 or Asn566 of E-cadherin was accompanied with the activation of the extracellular signal-regulated protein kinase signaling pathway. After treatment with PD98059, an inhibitor of the extraceilular signal-regulated protein kinase signaling pathway, wild-type E-cadherin transfected MDA-MB-435 and E-cadherin N-glycosylation-deficient mutant transfected MDA-MB-435 cells had equivalent numbers of cells in G1 phase. These findings implied that N-glycosylation might be crucial for E-cadherin-mediated suppression of cell cycle progression.

  1. 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....

  2. Prognostic Utility of Cell Cycle Progression Score in Men With Prostate Cancer After Primary External Beam Radiation Therapy

    Energy Technology Data Exchange (ETDEWEB)

    Freedland, Stephen J., E-mail: steve.freedland@duke.edu [Department of Surgery, Durham VA Medical Center, Durham, North Carolina (United States); Department of Surgery (Urology), Duke University School of Medicine, Durham, North Carolina (United States); Department of Pathology, Duke University School of Medicine, Durham, North Carolina (United States); Gerber, Leah [Department of Surgery, Durham VA Medical Center, Durham, North Carolina (United States); Department of Surgery (Urology), Duke University School of Medicine, Durham, North Carolina (United States); Department of Pathology, Duke University School of Medicine, Durham, North Carolina (United States); Reid, Julia; Welbourn, William; Tikishvili, Eliso; Park, Jimmy; Younus, Adib; Gutin, Alexander; Sangale, Zaina; Lanchbury, Jerry S. [Myriad Genetics, Inc, Salt Lake City, Utah (United States); Salama, Joseph K. [Department of Radiation Oncology, Durham VA Medical Center, Durham, North Carolina (United States); Department of Radiation Oncology, Duke University School of Medicine, Durham, North Carolina (United States); Stone, Steven [Myriad Genetics, Inc, Salt Lake City, Utah (United States)

    2013-08-01

    Purpose: To evaluate the prognostic utility of the cell cycle progression (CCP) score, a RNA signature based on the average expression level of 31 CCP genes, for predicting biochemical recurrence (BCR) in men with prostate cancer treated with external beam radiation therapy (EBRT) as their primary curative therapy. Methods and Materials: The CCP score was derived retrospectively from diagnostic biopsy specimens of men diagnosed with prostate cancer from 1991 to 2006 (n=141). All patients were treated with definitive EBRT; approximately half of the cohort was African American. Outcome was time from EBRT to BCR using the Phoenix definition. Median follow-up for patients without BCR was 4.8 years. Association with outcome was evaluated by Cox proportional hazards survival analysis and likelihood ratio tests. Results: Of 141 patients, 19 (13%) had BCR. The median CCP score for patient samples was 0.12. In univariable analysis, CCP score significantly predicted BCR (P=.0017). The hazard ratio for BCR was 2.55 for 1-unit increase in CCP score (equivalent to a doubling of gene expression). In a multivariable analysis that included Gleason score, prostate-specific antigen, percent positive cores, and androgen deprivation therapy, the hazard ratio for CCP changed only marginally and remained significant (P=.034), indicating that CCP provides prognostic information that is not provided by standard clinical parameters. With 10-year censoring, the CCP score was associated with prostate cancer-specific mortality (P=.013). There was no evidence for interaction between CCP and any clinical variable, including ethnicity. Conclusions: Among men treated with EBRT, the CCP score significantly predicted outcome and provided greater prognostic information than was available with clinical parameters. If validated in a larger cohort, CCP score could identify high-risk men undergoing EBRT who may need more aggressive therapy.

  3. Prognostic Utility of Cell Cycle Progression Score in Men With Prostate Cancer After Primary External Beam Radiation Therapy

    International Nuclear Information System (INIS)

    Purpose: To evaluate the prognostic utility of the cell cycle progression (CCP) score, a RNA signature based on the average expression level of 31 CCP genes, for predicting biochemical recurrence (BCR) in men with prostate cancer treated with external beam radiation therapy (EBRT) as their primary curative therapy. Methods and Materials: The CCP score was derived retrospectively from diagnostic biopsy specimens of men diagnosed with prostate cancer from 1991 to 2006 (n=141). All patients were treated with definitive EBRT; approximately half of the cohort was African American. Outcome was time from EBRT to BCR using the Phoenix definition. Median follow-up for patients without BCR was 4.8 years. Association with outcome was evaluated by Cox proportional hazards survival analysis and likelihood ratio tests. Results: Of 141 patients, 19 (13%) had BCR. The median CCP score for patient samples was 0.12. In univariable analysis, CCP score significantly predicted BCR (P=.0017). The hazard ratio for BCR was 2.55 for 1-unit increase in CCP score (equivalent to a doubling of gene expression). In a multivariable analysis that included Gleason score, prostate-specific antigen, percent positive cores, and androgen deprivation therapy, the hazard ratio for CCP changed only marginally and remained significant (P=.034), indicating that CCP provides prognostic information that is not provided by standard clinical parameters. With 10-year censoring, the CCP score was associated with prostate cancer-specific mortality (P=.013). There was no evidence for interaction between CCP and any clinical variable, including ethnicity. Conclusions: Among men treated with EBRT, the CCP score significantly predicted outcome and provided greater prognostic information than was available with clinical parameters. If validated in a larger cohort, CCP score could identify high-risk men undergoing EBRT who may need more aggressive therapy

  4. Cell cycle control in Alphaproteobacteria.

    Science.gov (United States)

    Collier, Justine

    2016-04-01

    Alphaproteobacteria include many medically and environmentally important organisms. Despite the diversity of their niches and lifestyles, from free-living to host-associated, they usually rely on very similar mechanisms to control their cell cycles. Studies on Caulobacter crescentus still lay the foundation for understanding the molecular details of pathways regulating DNA replication and cell division and coordinating these two processes with other events of the cell cycle. This review highlights recent discoveries on the regulation and the mode of action of conserved global regulators and small molecules like c-di-GMP and (p)ppGpp, which play key roles in cell cycle control. It also describes several newly identified mechanisms that modulate cell cycle progression in response to stresses or environmental conditions. PMID:26871482

  5. DNA damage during G2 phase does not affect cell cycle progression of the green alga Scenedesmus quadricauda.

    Directory of Open Access Journals (Sweden)

    Monika Hlavová

    Full Text Available DNA damage is a threat to genomic integrity in all living organisms. Plants and green algae are particularly susceptible to DNA damage especially that caused by UV light, due to their light dependency for photosynthesis. For survival of a plant, and other eukaryotic cells, it is essential for an organism to continuously check the integrity of its genetic material and, when damaged, to repair it immediately. Cells therefore utilize a DNA damage response pathway that is responsible for sensing, reacting to and repairing damaged DNA. We have studied the effect of 5-fluorodeoxyuridine, zeocin, caffeine and combinations of these on the cell cycle of the green alga Scenedesmus quadricauda. The cells delayed S phase and underwent a permanent G2 phase block if DNA metabolism was affected prior to S phase; the G2 phase block imposed by zeocin was partially abolished by caffeine. No cell cycle block was observed if the treatment with zeocin occurred in G2 phase and the cells divided normally. CDKA and CDKB kinases regulate mitosis in S. quadricauda; their kinase activities were inhibited by Wee1. CDKA, CDKB protein levels were stabilized in the presence of zeocin. In contrast, the protein level of Wee1 was unaffected by DNA perturbing treatments. Wee1 therefore does not appear to be involved in the DNA damage response in S. quadricauda. Our results imply a specific reaction to DNA damage in S. quadricauda, with no cell cycle arrest, after experiencing DNA damage during G2 phase.

  6. Repair and cell cycle response in cells exposed to environmental biohazards. Progress report, June 1, 1980-May 31, 1981

    International Nuclear Information System (INIS)

    Research progress for the period June 1, 1980 through May 31, 1981 is reported. Topics include: (1) repair of damage by psoralen plus near-uv light; (2) in vitro repair of transforming DNA; (3) photobiology of halogenated DNA; and (4) DNA repair in toluene-treated Escherichia coli containing BU-DNA

  7. Pan-Bcl-2 inhibitor obatoclax delays cell cycle progression and blocks migration of colorectal cancer cells.

    Directory of Open Access Journals (Sweden)

    Bruno Christian Koehler

    Full Text Available Despite the fact that new treatment regimes have improved overall survival of patients challenged by colorectal cancer (CRC, prognosis in the metastatic situation is still restricted. The Bcl-2 family of proteins has been identified as promising anti cancer drug target. Even though small molecules targeting Bcl-2 proteins are in clinical trials, little is known regarding their effects on CRC. The aim of this study was to preclinically investigate the value of ABT-737 and Obatoclax as anticancer drugs for CRC treatment. The effects of the BH3-mimetics ABT-737 and Obatoclax on CRC cells were assessed using viability and apoptosis assays. Wound healing migration and boyden chamber invasion assays were applied. 3-dimensional cell cultures were used for long term assessment of invasion and proliferation. Clinically relevant concentrations of pan-Bcl-2 inhibitor Obatoclax did not induce cell death. In contrast, the BH3-mimetic ABT-737 induced apoptosis in a dose dependent manner. Obatoclax caused a cell line specific slowdown of CRC cell growth. Furthermore, Obatoclax, but not ABT-737, recovered E-Cadherin expression and led to impaired migration and invasion of CRC cells. The proliferative capacity and invasiveness of CRC cells was strikingly inhibited by low dose Obatoclax in long term 3-dimensional cell cultures. Obatoclax, but not ABT-737, caused a G1-phase arrest accompanied by a downregulation of Cyclin D1 and upregulation of p27 and p21. Overexpression of Mcl-1, Bcl-xL or Bcl-2 reversed the inhibitory effect of Obatoclax on migration but failed to restore the proliferative capacity of Obatoclax-treated CRC cells. The data presented indicate broad and multifaceted antitumor effects of the pan-Bcl-2 inhibitor Obatoclax on CRC cells. In contrast to ABT-737, Obatoclax inhibited migration, invasion and proliferation in sublethal doses. In summary, this study recommends pan-Bcl-2 inhibition as a promising approach for clinical trials in CRC.

  8. Cell cycle and cell signal transduction in marine phytoplankton

    Institute of Scientific and Technical Information of China (English)

    LIU Jingwen; JIAO Nianzhi; CAI Huinong

    2006-01-01

    As unicellular phytoplankton, the growth of a marine phytoplankton population results directly from the completion of a cell cycle, therefore, cell-environment communication is an important way which involves signal transduction pathways to regulate cell cycle progression and contribute to growth, metabolism and primary production and respond to their surrounding environment in marine phytoplankton. Cyclin-CDK and CaM/Ca2+ are essentially key regulators in control of cell cycle and signal transduction pathway, which has important values on both basic research and applied biotechnology. This paper reviews progress made in this research field, which involves the identification and characterization of cyclins and cell signal transduction system, cell cycle control mechanisms in marine phytoplankton cells, cell cycle proteins as a marker of a terminal event to estimate the growth rate of phytoplankton at the species level, cell cycle-dependent toxin production of toxic algae and cell cycle progression regulated by environmental factors.

  9. 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)

    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 (P1 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 G1-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

  10. Repair and cell cycle response in cells exposed to environmental biohazards. Progress report, 1 June 1982-31 May 1983

    International Nuclear Information System (INIS)

    The research program has attempted to determine low environmental agents, especially ionizing radiation, interact with DNA and how the cells respond to the resulting damage. The focus has been on the spectrum of damage generated in DNA, the kinds of damage that can be repaired, and the mechanisms of repair. The effects of radioprotective agents and certain sensitizing conditions on breakage of DNA in bacterial cells by ionizing radiation, and mechanisms of enzymatic excision of pyrimidine dimers and other DNA adducts have been studied

  11. Enhanced selectivity of hyperthermic purging of human progenitor cells using Goralatide, an inhibitor of cell cycle progression

    NARCIS (Netherlands)

    Wierenga, PK; Brenner, MK; Konings, AWT

    1998-01-01

    Recurrence of leukemia is a major problem after autologous stem cell transplantation. One potential means of reducing this risk is to purge the autologous transplant in vitro by hyperthermia, We have demonstrated that after a hyperthermic treatment of 120 min at 43 degrees C, the leukemic progenitor

  12. Muscarinic acetylcholine receptor down-regulation limits the extent of inhibition of cell cycle progression in Chinese hamster ovary cells.

    OpenAIRE

    Detjen, K.; Yang, J; Logsdon, C D

    1995-01-01

    Cellular desensitization is believed to be important for growth control but direct evidence is lacking. In the current study we compared effects of wild-type and down-regulation-resistant mutant m3 muscarinic receptors on Chinese hamster ovary (CHO-K1) cell desensitization, proliferation, and transformation. We found that down-regulation of m3 muscarinic acetylcholine receptors was the principal mechanism of desensitization of receptor-activated inositol phosphate phospholipid hydrolysis in t...

  13. Overexpression of high molecular weight FGF-2 forms inhibits glioma growth by acting on cell-cycle progression and protein translation

    International Nuclear Information System (INIS)

    In order to clarify the role of HMW FGF-2 in glioma development and angiogenesis, we over-expressed different human FGF-2 isoforms in C6 rat glioma cell line using a tetracycline-regulated expression system. Phenotypic modifications were analyzed in vitro and compared to untransfected cells or to cells over-expressing 18 kDa FGF-2 or all FGF-2 isoforms. In particular, we demonstrate that HMW FGF-2 has unique features in inhibiting glioma cell proliferation. HMW FGF-2 expressing cells showed a cell-cycle arrest at the G2M, demonstrating a role of HMW FGF-2 in controlling the entry in mitosis. Moreover, hydroxyurea was ineffective in blocking cells at the G1S boundary when HMW FGF-2 was expressed. We also show that the HMW FGF-2 isoforms inhibit 4E-BP1 phosphorylation at critical sites restoring the translation inhibitory activity of 4E-BP1. In vivo, inhibition of tumor growth was observed when cells expressed HMW FGF-2. This indicates that HMW FGF-2 inhibits tumor growth in glioma cells by acting on cell-cycle progression and protein translation

  14. Stimulative Effects of Low Intensity He-Ne Laser Irradiation on the Proliferative Potential and Cell-Cycle Progression of Myoblasts in Culture

    Directory of Open Access Journals (Sweden)

    Cui-Ping Zhang

    2014-01-01

    Full Text Available Low intensity laser irradiation (LILI was found to promote the regeneration of skeletal muscle in vivo but the cellular mechanisms are not fully understood. Myoblasts, normally quiescent and inactivated in adult skeletal muscle, are a type of myogenic progenitor cells and considered as the major candidates responsible for muscle regeneration. The aim of the present study was to study the effect of LILI on the growth potential and cell-cycle progression of the cultured myoblasts. Primary myoblasts isolated from rat hind legs were cultured in nutrient-deficient medium for 36 hours and then irradiated by helium-neon laser at a certain energy density. Immunohistochemical and flow cytometric analysis revealed that laser irradiation could increase the expression of cellular proliferation marker and the amount of cell subpopulations in the proliferative phase as compared with the nonirradiated control group. Meanwhile, the expressions of cell-cycle regulatory proteins in the laser-treated myoblasts were markedly upregulated as compared to the unirradiated cells, indicating that LILI could promote the reentry of quiescent myoblasts into the cell division cycle. These results suggest that LILI at certain fluences could promote their proliferation, thus contributing to the skeletal muscle regeneration following trauma and myopathic diseases.

  15. Cellular morphometry and cycling cell populations of human and dog bronchi. Annual progress report, April 1, 1994--March 31, 1995

    International Nuclear Information System (INIS)

    Quantitative data of the human bronchial epithelial cells at possible risk for malignant transformation in lung cancer is crucial for accurate radon dosimetry and risk analysis. The nuclei of these cells may be targets for damage by α particles. Then it is important to determine the locations and other parameters of these nuclei in different airway generations, among smokers, non-smokers and ex-smokers, between men and women and in people of different ages. This proposal includes extended morphometric studies on electron micrographs of human bronchial epithelium of defined airway generations. The second part of this proposal describes the continuation of studies to quantitate the cycling tracheo-bronchial epithelial population(s) using proliferation markers and immunocytochemistry on paraffin sections. The proliferative potential of the airway mucosa of smokers, non-smokers, and ex-smokers, men and women, as well as individuals of different ages are being compared. Normal human bronchial linings are also being compared with normal adult dog bronchi and metaplastic and repairing human airways. Since cycling cells can be more sensitive to damage from carcinogens and radioactivity, the quantitative data from this project will allow the development of more accurate radon risk analysis

  16. Cellular morphometry and cycling cell populations of human and dog bronchi. Annual progress report, April 1, 1994--March 31, 1995

    Energy Technology Data Exchange (ETDEWEB)

    Robbins, E.S.

    1994-12-01

    Quantitative data of the human bronchial epithelial cells at possible risk for malignant transformation in lung cancer is crucial for accurate radon dosimetry and risk analysis. The nuclei of these cells may be targets for damage by {alpha} particles. Then it is important to determine the locations and other parameters of these nuclei in different airway generations, among smokers, non-smokers and ex-smokers, between men and women and in people of different ages. This proposal includes extended morphometric studies on electron micrographs of human bronchial epithelium of defined airway generations. The second part of this proposal describes the continuation of studies to quantitate the cycling tracheo-bronchial epithelial population(s) using proliferation markers and immunocytochemistry on paraffin sections. The proliferative potential of the airway mucosa of smokers, non-smokers, and ex-smokers, men and women, as well as individuals of different ages are being compared. Normal human bronchial linings are also being compared with normal adult dog bronchi and metaplastic and repairing human airways. Since cycling cells can be more sensitive to damage from carcinogens and radioactivity, the quantitative data from this project will allow the development of more accurate radon risk analysis.

  17. Blockage of PI3K/PKB/P27kip1 signaling pathway can antagonize 17β-estradiol-induced Ishikawa proliferation and cell cycle progression

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    @@ It is well-known that risk for endometrial adenocar- cinoma increases in patients with high level of estrogen that is unopposed by progestin. And activation of extracellular signal-regulated kinase (ERK)1 and phosphatidylinositol 3 kinase/protein kinase B (PI3K/PKB) pathway are responsible for hormone-dependent cell growth in endometrial carcinoma.2-4 PI3K produces phosphatidylinositol- 3-phosphates by phosphory- lating the D3 hydroxyl of phosphoinositides, leading to membrane translocation of PKB, on which PKB is phosphorylated and activated. Then the activated PKB can stimulate antiapoptotic cellular responses and block apoptotic functions of the cells, thus regulate the apoptosis and proliferation of cell, cell cycle progression, glucose usage, and angiogenesis.

  18. Pokemon enhances proliferation, cell cycle progression and anti-apoptosis activity of colorectal cancer independently of p14ARF-MDM2-p53 pathway.

    Science.gov (United States)

    Zhao, Yi; Yao, Yun-hong; Li, Li; An, Wei-fang; Chen, Hong-zen; Sun, Li-ping; Kang, Hai-xian; Wang, Sen; Hu, Xin-rong

    2014-12-01

    Pokemon has been showed to directly suppress p14(ARF) expression and also to overexpress in multiple cancers. However, p14(ARF)-MDM2-p53 pathway is usually aberrant in colorectal cancer (CRC). The aim is to confirm whether Pokemon plays a role in CRC and explore whether Pokemon works through p14(ARF)-MDM2-p53 pathway in CRC. Immunohistochemistry for Pokemon, p14(ARF) and Mtp53 protein was applied to 45 colorectal epitheliums (CREs), 42 colorectal adenomas (CRAs) and 66 CRCs. Pokemon was knocked down with RNAi technique in CRC cell line Lovo to detect mRNA expression of p14(ARF) with qRT-PCR, cell proliferation with CCK8 assay, and cell cycle and apoptosis with flowcytometry analysis. The protein expression rates were significantly higher in CRC (75.8%) than in CRE (22.2 %) or CRA (38.1%) for Pokemon and higher in CRC (53.0%) than in CRE (0) or CRA (4.8%) for Mtp53, but not significantly different in CRC (86.4 %) versus CRE (93.3%) or CRA (90.5 %) for p14(ARF). Higher expression rate of Pokemon was associated with lymph node metastasis and higher Duke's stage. After knockdown of Pokemon in Lovo cells, the mRNA level of p14(ARF) was not significantly changed, the cell proliferation ability was decreased by 20.6%, cell cycle was arrested by 55.7% in G0/G1 phase, and apoptosis rate was increased by 19.0%. Pokemon enhanced the oncogenesis of CRC by promoting proliferation, cell cycle progression and anti-apoptosis activity of CRC cells independently of p14(ARF)-MDM2-p53 pathway. This finding provided a novel idea for understanding and further studying the molecular mechanism of Pokemon on carcinogenesis of CRC. PMID:25367850

  19. DNA-PKcs plays a dominant role in the regulation of H2AX phosphorylation in response to DNA damage and cell cycle progression

    Directory of Open Access Journals (Sweden)

    Wang Yu

    2010-03-01

    Full Text Available Abstract Background When DNA double-strand breaks (DSB are induced by ionizing radiation (IR in cells, histone H2AX is quickly phosphorylated into γ-H2AX (p-S139 around the DSB site. The necessity of DNA-PKcs in regulating the phosphorylation of H2AX in response to DNA damage and cell cycle progression was investigated. Results The level of γH2AX in HeLa cells increased rapidly with a peak level at 0.25 - 1.0 h after 4 Gy γ irradiation. SiRNA-mediated depression of DNA-PKcs resulted in a strikingly decreased level of γH2AX. An increased γH2AX was also induced in the ATM deficient cell line AT5BIVA at 0.5 - 1.0 h after 4 Gy γ rays, and this IR-increased γH2AX in ATM deficient cells was dramatically abolished by the PIKK inhibitor wortmannin and the DNA-PKcs specific inhibitor NU7026. A high level of constitutive expression of γH2AX was observed in another ATM deficient cell line ATS4. The alteration of γH2AX level associated with cell cycle progression was also observed. HeLa cells with siRNA-depressed DNA-PKcs (HeLa-H1 or normal level DNA-PKcs (HeLa-NC were synchronized at the G1 phase with the thymidine double-blocking method. At ~5 h after the synchronized cells were released from the G1 block, the S phase cells were dominant (80% for both HeLa-H1 and HeLa-NC cells. At 8 - 9 h after the synchronized cells released from the G1 block, the proportion of G2/M population reached 56 - 60% for HeLa-NC cells, which was higher than that for HeLa H1 cells (33 - 40%. Consistently, the proportion of S phase for HeLa-NC cells decreased to ~15%; while a higher level (26 - 33% was still maintained for the DNA-PKcs depleted HeLa-H1 cells during this period. In HeLa-NC cells, the γH2AX level increased gradually as the cells were released from the G1 block and entered the G2/M phase. However, this γH2AX alteration associated with cell cycle progressing was remarkably suppressed in the DNA-PKcs depleted HeLa-H1 cells, while wortmannin and NU7026 could

  20. Non-coding RNA LINC00857 is predictive of poor patient survival and promotes tumor progression via cell cycle regulation in lung cancer

    Science.gov (United States)

    Wang, Lihui; He, Yanli; Liu, Weijun; Bai, Shengbin; Xiao, Lei; Zhang, Jie; Dhanasekaran, Saravana M.; Wang, Zhuwen; Kalyana-Sundaram, Shanker; Balbin, O. Alejandro; Shukla, Sudhanshu; Lu, Yi; Lin, Jules; Reddy, Rishindra M.; Carrott, Philip W.; Lynch, William R.; Chang, Andrew C.; Chinnaiyan, Arul M.; Beer, David G.; Zhang, Jian; Chen, Guoan

    2016-01-01

    We employed next generation RNA sequencing analysis to reveal dysregulated long non-coding RNAs (lncRNAs) in lung cancer utilizing 461 lung adenocarcinomas (LUAD) and 156 normal lung tissues from 3 separate institutions. We identified 281 lncRNAs with significant differential-expression between LUAD and normal lung tissue. LINC00857, a top deregulated lncRNAs, was overexpressed in tumors and significantly associated with poor survival in LUAD. knockdown of LINC00857 with siRNAs decreased tumor cell proliferation, colony formation, migration and invasion in vitro, as well as tumor growth in vivo. Overexpression of LINC00857 increased cancer cell proliferation, colony formation and invasion. Mechanistic analyses indicated that LINC00857 mediates tumor progression via cell cycle regulation. Our study highlights the diagnostic/prognostic potential of LINC00857 in LUAD besides delineating the functional and mechanistic aspects of its aberrant disease specific expression and potentially using as a new therapeutic target. PMID:26862852

  1. Non-coding RNA LINC00857 is predictive of poor patient survival and promotes tumor progression via cell cycle regulation in lung cancer.

    Science.gov (United States)

    Wang, Lihui; He, Yanli; Liu, Weijun; Bai, Shengbin; Xiao, Lei; Zhang, Jie; Dhanasekaran, Saravana M; Wang, Zhuwen; Kalyana-Sundaram, Shanker; Balbin, O Alejandro; Shukla, Sudhanshu; Lu, Yi; Lin, Jules; Reddy, Rishindra M; Carrott, Philip W; Lynch, William R; Chang, Andrew C; Chinnaiyan, Arul M; Beer, David G; Zhang, Jian; Chen, Guoan

    2016-03-01

    We employed next generation RNA sequencing analysis to reveal dysregulated long non-coding RNAs (lncRNAs) in lung cancer utilizing 461 lung adenocarcinomas (LUAD) and 156 normal lung tissues from 3 separate institutions. We identified 281 lncRNAs with significant differential-expression between LUAD and normal lung tissue. LINC00857, a top deregulated lncRNAs, was overexpressed in tumors and significantly associated with poor survival in LUAD. knockdown of LINC00857 with siRNAs decreased tumor cell proliferation, colony formation, migration and invasion in vitro, as well as tumor growth in vivo. Overexpression of LINC00857 increased cancer cell proliferation, colony formation and invasion. Mechanistic analyses indicated that LINC00857 mediates tumor progression via cell cycle regulation. Our study highlights the diagnostic/prognostic potential of LINC00857 in LUAD besides delineating the functional and mechanistic aspects of its aberrant disease specific expression and potentially using as a new therapeutic target. PMID:26862852

  2. Garcinol inhibits tumour cell proliferation, angiogenesis, cell cycle progression and induces apoptosis via NF-κB inhibition in oral cancer.

    Science.gov (United States)

    Aggarwal, Sadhna; Das, Satya N

    2016-06-01

    Garcinol, a polyisoprenylated benzophenone is extracted from the rind of the fruit of Garcinia indica, a plant found extensively in tropical regions. Its ability to inhibit tumour growth has been demonstrated in certain cancers. In this study, we evaluated the potential anti-tumour effects of garcinol on oral squamous cell carcinoma (OSCC) cells. Three OSCC cell lines (SCC-4, SCC-9 and SCC-25) were treated with garcinol for 48 h and its effect on growth and proliferation, clonogenic survival, cell cycle and apoptosis was studied by MTT, clonogenic assay, propidium iodide (PI) staining and annexin-V binding assay, respectively. The alteration in expression of NF-κB and COX-2 was studied by western blot analysis and that of VEGF by ELISA. Garcinol treatment significantly (p < 0.001) inhibited the growth and proliferation and colony formation of OSCC cells with a concomitant induction of apoptosis and cell cycle arrest. It did not show toxic effect on normal cells. It significantly (p < 0.05) reduced the expression of NK-κB and COX-2 expression in treated cells as compared to untreated controls besides inhibiting VEGF expression. It appears that garcinol exerts anti-proliferative, pro-apoptotic, cell-cycle regulatory and anti-angiogenic effects on oral cancer cells through inhibition of NF-κB and COX-2. Thus, garcinol may be developed as a potential chemopreventive and/or chemotherapeutic agent for treatment of oral squamous cell carcinoma. PMID:26662963

  3. The KRAB Zinc Finger Protein Roma/Zfp157 Is a Critical Regulator of Cell-Cycle Progression and Genomic Stability

    Directory of Open Access Journals (Sweden)

    Teresa L.F. Ho

    2016-04-01

    Full Text Available Regulation of DNA replication and cell division is essential for tissue growth and maintenance of genomic integrity and is particularly important in tissues that undergo continuous regeneration such as mammary glands. We have previously shown that disruption of the KRAB-domain zinc finger protein Roma/Zfp157 results in hyperproliferation of mammary epithelial cells (MECs during pregnancy. Here, we delineate the mechanism by which Roma engenders this phenotype. Ablation of Roma in MECs leads to unscheduled proliferation, replication stress, DNA damage, and genomic instability. Furthermore, mouse embryonic fibroblasts (MEFs depleted for Roma exhibit downregulation of p21Cip1 and geminin and have accelerated replication fork velocities, which is accompanied by a high rate of mitotic errors and polyploidy. In contrast, overexpression of Roma in MECs halts cell-cycle progression, whereas siRNA-mediated p21Cip1 knockdown ameliorates, in part, this phenotype. Thus, Roma is an essential regulator of the cell cycle and is required to maintain genomic stability.

  4. System-level design of bacterial cell cycle control

    OpenAIRE

    McAdams, Harley H.; Shapiro, Lucy

    2009-01-01

    Understanding of the cell cycle control logic in Caulobacter has progressed to the point where we now have an integrated view of the operation of an entire bacterial cell cycle system functioning as a state machine. Oscillating levels of a few temporally-controlled master regulator proteins in a cyclical circuit drive cell cycle progression. To a striking degree, the cell cycle regulation is a whole cell phenomenon. Phospho-signaling proteins and proteases dynamically deployed to specific loc...

  5. The Src homology 2 protein Shb promotes cell cycle progression in murine hematopoietic stem cells by regulation of focal adhesion kinase activity

    Energy Technology Data Exchange (ETDEWEB)

    Gustafsson, Karin [Department of Medical Cell Biology, Uppsala University, Uppsala 751 23 (Sweden); Heffner, Garrett; Wenzel, Pamela L.; Curran, Matthew [HHMI, Children' s Hospital Boston, Harvard Medical School, Boston, 02115 MA (United States); Grawé, Jan [Department of Genetics and Pathology, Uppsala University, Uppsala 75185 (Sweden); McKinney-Freeman, Shannon L. [Department of Hematology, St. Jude Children' s Research Hospital, Memphis, TN 38105 (United States); Daley, George Q. [HHMI, Children' s Hospital Boston, Harvard Medical School, Boston, 02115 MA (United States); Welsh, Michael, E-mail: michael.welsh@mcb.uu.se [Department of Medical Cell Biology, Uppsala University, Uppsala 751 23 (Sweden)

    2013-07-15

    The widely expressed adaptor protein Shb has previously been reported to contribute to T cell function due to its association with the T cell receptor and furthermore, several of Shb's known interaction partners are established regulators of blood cell development and function. In addition, Shb deficient embryonic stem cells displayed reduced blood cell colony formation upon differentiation in vitro. The aim of the current study was therefore to explore hematopoietic stem and progenitor cell function in the Shb knockout mouse. Shb deficient bone marrow contained reduced relative numbers of long-term hematopoietic stem cells (LT-HSCs) that exhibited lower proliferation rates. Despite this, Shb knockout LT-HSCs responded promptly by entering the cell cycle in response to genotoxic stress by 5-fluorouracil treatment. In competitive LT-HSC transplantations, Shb null cells initially engrafted as well as the wild-type cells but provided less myeloid expansion over time. Moreover, Shb knockout bone marrow cells exhibited elevated basal activities of focal adhesion kinase/Rac1/p21-activated kinase signaling and reduced responsiveness to Stem Cell Factor stimulation. Consequently, treatment with a focal adhesion kinase inhibitor increased Shb knockout LT-HSC proliferation. The altered signaling characteristics thus provide a plausible mechanistic explanation for the changes in LT-HSC proliferation since these signaling intermediates have all been shown to participate in LT-HSC cell cycle control. In summary, the loss of Shb dependent signaling in bone marrow cells, resulting in elevated focal adhesion kinase activity and reduced proliferative responses in LT-HSCs under steady state hematopoiesis, confers a disadvantage to the maintenance of LT-HSCs over time. -- Highlights: • Shb is an adaptor protein operating downstream of tyrosine kinase receptors. • Shb deficiency reduces hematopoietic stem cell proliferation. • The proliferative effect of Shb occurs via

  6. The Src homology 2 protein Shb promotes cell cycle progression in murine hematopoietic stem cells by regulation of focal adhesion kinase activity

    International Nuclear Information System (INIS)

    The widely expressed adaptor protein Shb has previously been reported to contribute to T cell function due to its association with the T cell receptor and furthermore, several of Shb's known interaction partners are established regulators of blood cell development and function. In addition, Shb deficient embryonic stem cells displayed reduced blood cell colony formation upon differentiation in vitro. The aim of the current study was therefore to explore hematopoietic stem and progenitor cell function in the Shb knockout mouse. Shb deficient bone marrow contained reduced relative numbers of long-term hematopoietic stem cells (LT-HSCs) that exhibited lower proliferation rates. Despite this, Shb knockout LT-HSCs responded promptly by entering the cell cycle in response to genotoxic stress by 5-fluorouracil treatment. In competitive LT-HSC transplantations, Shb null cells initially engrafted as well as the wild-type cells but provided less myeloid expansion over time. Moreover, Shb knockout bone marrow cells exhibited elevated basal activities of focal adhesion kinase/Rac1/p21-activated kinase signaling and reduced responsiveness to Stem Cell Factor stimulation. Consequently, treatment with a focal adhesion kinase inhibitor increased Shb knockout LT-HSC proliferation. The altered signaling characteristics thus provide a plausible mechanistic explanation for the changes in LT-HSC proliferation since these signaling intermediates have all been shown to participate in LT-HSC cell cycle control. In summary, the loss of Shb dependent signaling in bone marrow cells, resulting in elevated focal adhesion kinase activity and reduced proliferative responses in LT-HSCs under steady state hematopoiesis, confers a disadvantage to the maintenance of LT-HSCs over time. -- Highlights: • Shb is an adaptor protein operating downstream of tyrosine kinase receptors. • Shb deficiency reduces hematopoietic stem cell proliferation. • The proliferative effect of Shb occurs via increased

  7. Akt/Protein Kinase B-Dependent Phosphorylation and Inactivation of WEE1Hu Promote Cell Cycle Progression at G2/M Transition

    Science.gov (United States)

    Katayama, Kazuhiro; Fujita, Naoya; Tsuruo, Takashi

    2005-01-01

    The serine/threonine kinase Akt is known to promote cell growth by regulating the cell cycle in G1 phase through activation of cyclin/Cdk kinases and inactivation of Cdk inhibitors. However, how the G2/M phase is regulated by Akt remains unclear. Here, we show that Akt counteracts the function of WEE1Hu. Inactivation of Akt by chemotherapeutic drugs or the phosphatidylinositide-3-OH kinase inhibitor LY294002 induced G2/M arrest together with the inhibitory phosphorylation of Cdc2. Because the increased Cdc2 phosphorylation was completely suppressed by wee1hu gene silencing, WEE1Hu was associated with G2/M arrest induced by Akt inactivation. Further analyses revealed that Akt directly bound to and phosphorylated WEE1Hu during the S to G2 phase. Serine-642 was identified as an Akt-dependent phosphorylation site. WEE1Hu kinase activity was not affected by serine-642 phosphorylation. We revealed that serine-642 phosphorylation promoted cytoplasmic localization of WEE1Hu. The nuclear-to-cytoplasmic translocation was mediated by phosphorylation-dependent WEE1Hu binding to 14-3-3θ but not 14-3-3β or -σ. These results indicate that Akt promotes G2/M cell cycle progression by inducing phosphorylation-dependent 14-3-3θ binding and cytoplasmic localization of WEE1Hu. PMID:15964826

  8. The Exon Junction Complex Controls the Efficient and Faithful Splicing of a Subset of Transcripts Involved in Mitotic Cell-Cycle Progression.

    Science.gov (United States)

    Fukumura, Kazuhiro; Wakabayashi, Shunichi; Kataoka, Naoyuki; Sakamoto, Hiroshi; Suzuki, Yutaka; Nakai, Kenta; Mayeda, Akila; Inoue, Kunio

    2016-01-01

    The exon junction complex (EJC) that is deposited onto spliced mRNAs upstream of exon-exon junctions plays important roles in multiple post-splicing gene expression events, such as mRNA export, surveillance, localization, and translation. However, a direct role for the human EJC in pre-mRNA splicing has not been fully understood. Using HeLa cells, we depleted one of the EJC core components, Y14, and the resulting transcriptome was analyzed by deep sequencing (RNA-Seq) and confirmed by RT-PCR. We found that Y14 is required for efficient and faithful splicing of a group of transcripts that is enriched in short intron-containing genes involved in mitotic cell-cycle progression. Tethering of EJC core components (Y14, eIF4AIII or MAGOH) to a model reporter pre-mRNA harboring a short intron showed that these core components are prerequisites for the splicing activation. Taken together, we conclude that the EJC core assembled on pre-mRNA is critical for efficient and faithful splicing of a specific subset of short introns in mitotic cell cycle-related genes. PMID:27490541

  9. Lamin b1 polymorphism influences morphology of the nuclear envelope, cell cycle progression, and risk of neural tube defects in mice.

    Directory of Open Access Journals (Sweden)

    Sandra C P De Castro

    Full Text Available Neural tube defects (NTDs, including spina bifida and anencephaly, are common birth defects whose complex multigenic causation has hampered efforts to delineate their molecular basis. The effect of putative modifier genes in determining NTD susceptibility may be investigated in mouse models, particularly those that display partial penetrance such as curly tail, a strain in which NTDs result from a hypomorphic allele of the grainyhead-like-3 gene. Through proteomic analysis, we found that the curly tail genetic background harbours a polymorphic variant of lamin B1, lacking one of a series of nine glutamic acid residues. Lamins are intermediate filament proteins of the nuclear lamina with multiple functions that influence nuclear structure, cell cycle properties, and transcriptional regulation. Fluorescence loss in photobleaching showed that the variant lamin B1 exhibited reduced stability in the nuclear lamina. Genetic analysis demonstrated that the variant also affects neural tube closure: the frequency of spina bifida and anencephaly was reduced three-fold when wild-type lamin B1 was bred into the curly tail strain background. Cultured fibroblasts expressing variant lamin B1 show significantly increased nuclear dysmorphology and diminished proliferative capacity, as well as premature senescence, associated with reduced expression of cyclins and Smc2, and increased expression of p16. The cellular basis of spinal NTDs in curly tail embryos involves a proliferation defect localised to the hindgut epithelium, and S-phase progression was diminished in the hindgut of embryos expressing variant lamin B1. These observations indicate a mechanistic link between altered lamin B1 function, exacerbation of the Grhl3-mediated cell proliferation defect, and enhanced susceptibility to NTDs. We conclude that lamin B1 is a modifier gene of major effect for NTDs resulting from loss of Grhl3 function, a role that is likely mediated via the key function of lamin B1

  10. Inhibition of phosphatidylinositol 3-kinase promotes tumor cell resistance to chemotherapeutic agents via a mechanism involving delay in cell cycle progression

    Energy Technology Data Exchange (ETDEWEB)

    McDonald, Gail T.; Sullivan, Richard; Pare, Genevieve C.; Graham, Charles H., E-mail: grahamc@queensu.ca

    2010-11-15

    Approaches to overcome chemoresistance in cancer cells have involved targeting specific signaling pathways such as the phosphatidylinositol 3-kinase (PI3K) pathway, a stress response pathway known to be involved in the regulation of cell survival, apoptosis and growth. The present study determined the effect of PI3K inhibition on the clonogenic survival of human cancer cells following exposure to various chemotherapeutic agents. Treatment with the PI3K inhibitors LY294002 or Compound 15e resulted in increased survival of MDA-MB-231 breast carcinoma cells after exposure to doxorubicin, etoposide, 5-fluorouracil, and vincristine. Increased survival following PI3K inhibition was also observed in DU-145 prostate, HCT-116 colon and A-549 lung carcinoma cell lines exposed to doxorubicin. Increased cell survival mediated by LY294002 was correlated with a decrease in cell proliferation, which was linked to an increase in the proportion of cells in the G{sub 1} phase of the cell cycle. Inhibition of PI3K signaling also resulted in higher levels of the cyclin-dependent kinase inhibitors p21{sup Waf1/Cip1} and p27{sup Kip1}; and knockdown of p27{sup kip1} with siRNA attenuated resistance to doxorubicin in cells treated with LY294002. Incubation in the presence of LY294002 after exposure to doxorubicin resulted in decreased cell survival. These findings provide evidence that PI3K inhibition leads to chemoresistance in human cancer cells by causing a delay in cell cycle; however, the timing of PI3K inhibition (either before or after exposure to anti-cancer agents) may be a critical determinant of chemosensitivity.

  11. Inhibition of phosphatidylinositol 3-kinase promotes tumor cell resistance to chemotherapeutic agents via a mechanism involving delay in cell cycle progression

    International Nuclear Information System (INIS)

    Approaches to overcome chemoresistance in cancer cells have involved targeting specific signaling pathways such as the phosphatidylinositol 3-kinase (PI3K) pathway, a stress response pathway known to be involved in the regulation of cell survival, apoptosis and growth. The present study determined the effect of PI3K inhibition on the clonogenic survival of human cancer cells following exposure to various chemotherapeutic agents. Treatment with the PI3K inhibitors LY294002 or Compound 15e resulted in increased survival of MDA-MB-231 breast carcinoma cells after exposure to doxorubicin, etoposide, 5-fluorouracil, and vincristine. Increased survival following PI3K inhibition was also observed in DU-145 prostate, HCT-116 colon and A-549 lung carcinoma cell lines exposed to doxorubicin. Increased cell survival mediated by LY294002 was correlated with a decrease in cell proliferation, which was linked to an increase in the proportion of cells in the G1 phase of the cell cycle. Inhibition of PI3K signaling also resulted in higher levels of the cyclin-dependent kinase inhibitors p21Waf1/Cip1 and p27Kip1; and knockdown of p27kip1 with siRNA attenuated resistance to doxorubicin in cells treated with LY294002. Incubation in the presence of LY294002 after exposure to doxorubicin resulted in decreased cell survival. These findings provide evidence that PI3K inhibition leads to chemoresistance in human cancer cells by causing a delay in cell cycle; however, the timing of PI3K inhibition (either before or after exposure to anti-cancer agents) may be a critical determinant of chemosensitivity.

  12. Glutathione transferases P1/P2 regulate the timing of signaling pathway activations and cell cycle progression during mouse liver regeneration.

    Science.gov (United States)

    Pajaud, J; Ribault, C; Ben Mosbah, I; Rauch, C; Henderson, C; Bellaud, P; Aninat, C; Loyer, P; Morel, F; Corlu, A

    2015-01-01

    Glutathione transferases (GST) are phase II enzymes catalyzing the detoxification of endogenous noxious compounds and xenobiotics. They also regulate phosphorylation activities of MAPKinases in a catalytic-independent manner. Previous studies have demonstrated the regulation of JNK-dependent pathway by GSTP1/2. Considering the crucial role of JNK in the early steps of the hepatocyte cell cycle, we sought to determine whether GSTP1/2 were essential for hepatocyte proliferation following partial hepatectomy (PH). Using a conventional double knockout mouse model for the Gstp1 and Gstp2 genes, we found that the lack of GSTP1/P2 reduced the rate of DNA replication and mitotic index during the first wave of hepatocyte proliferation. The lowered proliferation was associated with the decrease in TNFalpha and IL-6 plasma concentrations, reduced hepatic HGF expression and delayed and/or altered activation of STAT3, JNK and ERK1/2 signaling pathways. In addition, the expression and/or activation of cell cycle regulators such as Cyclin D1, CDK4, E2F1 and MCM7 was postponed demonstrating that the absence of GSTP1/2 delayed the entry into and progression through the G1 phase of the cell cycle and impaired the synchrony of proliferation in hepatocytes following PH. Furthermore, while JNK and its downstream targets c-Jun and ATF2 were activated during the early steps of the liver regeneration in wild-type animals, the constitutively active JNK found in the quiescent liver of Gstp1/2 knockout mice underwent a decrease in its activity after PH. Transient induction of antioxidant enzymes and nitric oxide synthase were also delayed or repressed during the regenerative response. Altogether our results demonstrate that GSTP1/2 are a critical regulators of hepatocyte proliferation in the initial phases of liver regeneration. PMID:25590808

  13. Effects of caffeine on X-irradiated synchronous, asynchronous and plateau phase mouse ascites cells: the importance of progression through the cell cycle for caffeine enhancement of killing

    International Nuclear Information System (INIS)

    Caffeine potentiated the killing effect of X-rays on exponentially growing cells giving rise to exponential curves (D0=(0.8+-0.05)Gy) at 4mM and 14 hours treatment. Irradiated plateau phase cells were less sensitive. Exponentially growing cells also became less sensitive to the effects of caffeine when they were incubated in the conditioned medium of plateau phase cells(C-medium) in which cell growth was considerably inhibited. Low caffeine concentrations(2mM) enhanced X-ray induced killing of cells irradiated in G1-,G1/S- or S-phase, but more effectively G2-phase cells. High caffeine concentrations (6mM) enhanced killing of cells in all phases of the cell cycle. Incubation of synchronized populations in C-medium during treatment with caffeine (2mM and 6mM) resulted in less potentiation than in cells treated in fresh medium. The expression of X-ray induced potentially lethal damage caused by 6mM caffeine in cells irradiated in various phases resulted in an exponential survival curve with a mean lethal dose of (0.8+-0.05)Gy, but the time of caffeine treatment necessary to reach this curve was different for cells irradiated in different phases. PLD repair, measured as loss of sensitivity to 6mM caffeine (4 hours treatment) was of 1-2 hours duration. (author)

  14. Interaction of FLASH with Arsenite Resistance Protein 2 Is Involved in Cell Cycle Progression at S Phase▿ †

    OpenAIRE

    Kiriyama, Maria; KOBAYASHI Yohei; Saito, Motoki; Ishikawa, Fuyuki; Yonehara, Shin

    2009-01-01

    FLASH has been shown to be required for S phase progression and to interact with a nuclear protein, ataxia-telangiectasia locus (NPAT), a component of Cajal bodies in the nucleus and an activator of histone transcription. We investigated the role of human FLASH by using an inducible FLASH knockdown system in the presence or absence of various mutant forms of mouse FLASH. While carboxyl-terminal deletion mutants of FLASH, which do not interact with NPAT, can support S phase progression, its am...

  15. Bitter melon extract impairs prostate cancer cell cycle progression and delays prostatic intraepithelial neoplasia in TRAMP model

    OpenAIRE

    Ru, Peng; Steele, Robert; Nerurkar, Pratibha V.; Phillips, Nancy; Ray, Ratna

    2011-01-01

    Prostate cancer remains the second leading cause of cancer deaths among American men. Earlier diagnosis increases survival rate in patients. However, treatments for advanced disease are limited to hormone ablation techniques and palliative care. Thus, new methods of treatment and prevention are necessary for inhibiting disease progression to a hormone refractory state. One of the approaches to control prostate cancer is prevention through diet, which inhibits one or more neoplastic events and...

  16. In Silico Design and Biological Evaluation of a Dual Specificity Kinase Inhibitor Targeting Cell Cycle Progression and Angiogenesis

    OpenAIRE

    Latham, AM; Kankanala, J; Fearnley, GW; Gage, MC; Kearney, MT; Homer-Vanniasinkam, S; Wheatcroft, SB; Fishwick, CWG; Ponnambalam, S.

    2014-01-01

    Background Protein kinases play a central role in tumor progression, regulating fundamental processes such as angiogenesis, proliferation and metastasis. Such enzymes are an increasingly important class of drug target with small molecule kinase inhibitors being a major focus in drug development. However, balancing drug specificity and efficacy is problematic with off-target effects and toxicity issues. Methodology We have utilized a rational in silico-based approach to demonstrate the design ...

  17. A Positive Feedback Loop between ATOH7 and a Notch Effector Regulates Cell-Cycle Progression and Neurogenesis in the Retina

    Directory of Open Access Journals (Sweden)

    Florence Chiodini

    2013-03-01

    Full Text Available The HES proteins are known Notch effectors and have long been recognized as important in inhibiting neuronal differentiation. However, the roles that they play in the specification of neuronal fate remain largely unknown. Here, we show that in the differentiating retinal epithelium, the proneural protein ATOH7 (ATH5 is required for the activation of the transcription of the Hes5.3 gene before the penultimate mitosis of progenitor cells. We further show that the HES5.3 protein slows down the cell-cycle progression of Atoh7-expressing cells, thereby establishing conditions for Atoh7 to reach a high level of expression in S phase and induce neuronal differentiation prior to the ultimate mitosis. Our study uncovers how a proneural protein recruits a protein known to be a component of the Notch signaling pathway in order to regulate the transition between an initial phase of selection among uncommitted progenitors and a later phase committing the selected progenitors to neuronal differentiation.

  18. Collaborative Control of Cell Cycle Progression by the RNA Exonuclease Dis3 and Ras Is Conserved Across Species.

    Science.gov (United States)

    Snee, Mark J; Wilson, William C; Zhu, Yi; Chen, Shin-Yu; Wilson, Beth A; Kseib, Cedric; O'Neal, Julie; Mahajan, Nitin; Tomasson, Michael H; Arur, Swathi; Skeath, James B

    2016-06-01

    Dis3 encodes a conserved RNase that degrades or processes all RNA species via an N-terminal PilT N terminus (PIN) domain and C-terminal RNB domain that harbor, respectively, endonuclease activity and 3'-5' exonuclease activity. In Schizosaccharomyces pombe, dis3 mutations cause chromosome missegregation and failure in mitosis, suggesting dis3 promotes cell division. In humans, apparently hypomorphic dis3 mutations are found recurrently in multiple myeloma, suggesting dis3 opposes cell division. Except for the observation that RNAi-mediated depletion of dis3 function drives larval arrest and reduces tissue growth in Drosophila, the role of dis3 has not been rigorously explored in higher eukaryotic systems. Using the Drosophila system and newly generated dis3 null alleles, we find that absence of dis3 activity inhibits cell division. We uncover a conserved CDK1 phosphorylation site that when phosphorylated inhibits Dis3's exonuclease, but not endonuclease, activity. Leveraging this information, we show that Dis3's exonuclease function is required for mitotic cell division: in its absence, cells are delayed in mitosis and exhibit aneuploidy and overcondensed chromosomes. In contrast, we find that modest reduction of dis3 function enhances cell proliferation in the presence of elevated Ras activity, apparently by accelerating cells through G2/M even though each insult by itself delays G2/M. Additionally, we find that dis3 and ras genetically interact in worms and that dis3 can enhance cell proliferation under growth stimulatory conditions in murine B cells. Thus, reduction, but not absence, of dis3 activity can enhance cell proliferation in higher organisms. PMID:27029730

  19. Tyrosine phosphorylation of estradiol receptor by Src regulates its hormone-dependent nuclear export and cell cycle progression in breast cancer cells.

    Science.gov (United States)

    Castoria, G; Giovannelli, P; Lombardi, M; De Rosa, C; Giraldi, T; de Falco, A; Barone, M V; Abbondanza, C; Migliaccio, A; Auricchio, F

    2012-11-15

    We report that in breast cancer cells, tyrosine phosphorylation of the estradiol receptor alpha (ERalpha) by Src regulates cytoplasmic localization of the receptor and DNA synthesis. Inhibition of Src or use of a peptide mimicking the ERalpha p-Tyr537 sequence abolishes ERalpha tyrosine phosphorylation and traps the receptor in nuclei of estradiol-treated MCF-7 cells. An ERalpha mutant carrying a mutation of Tyr537 to phenylalanine (ER537F) persistently localizes in nuclei of various cell types. In contrast with ERalpha wt, ER537F does not associate with Ran and its interaction with Crm1 is insensitive to estradiol. Thus, independently of estradiol, ER537F is retained in nuclei, where it entangles FKHR-driving cell cycle arrest. Chromatin immunoprecipitation analysis reveals that overexpression of ER537F in breast cancer cells enhances FKHR interaction with cyclin D1 promoter. This mutant also counteracts cell transformation by the activated forms of Src or PI3-K. In conclusion, in addition to regulating receptor localization, ERalpha phosphorylation by Src is required for hormone responsiveness of DNA synthesis in breast cancer cells. PMID:22266855

  20. 2-Methoxyestradiol blocks cell-cycle progression at the G2/M phase and induces apoptosis in human acute T lymphoblastic leukemia CEM cells

    Institute of Scientific and Technical Information of China (English)

    Xueya Zhang; Haobo Huang; Zhenshu Xu; Rong Zhan

    2010-01-01

    2-Methoxyestradiol(2-ME2)is an endogenous metabolite of 17β-estradiol(E2)with estrogen receptor-independent anti-cancer activity.The current study sought to deter mine the mechanism of anti-cancer activity of 2-ME2 in human acute T lymphoblastic leukemia CEM cells.Results showed that 2-ME2 markedly suppressed proliferation of CEM cells in a time-and dose-dependent manner.2-ME2-treated CEM cells underwent typical apoptotic changes.Exposure to 2-ME2 led to G2/M phase cell-cycle arrest,which preceded apoptosis characterized by the appearance of a sub-G1 cell population.In addition,cytosolic cytochrome c release,increased procaspase-9 and-3 expressions,poly(ADP-ribose)polymerase (PARP)cleavage,and induced expression of caspase-8 were detected,suggesting that both the intrinsic apoptotic pathway and extrinsic apoptotic pathway were involved in 2-ME2-induced apoptosis.Moreover,the expression level of p21 protein was upregulated,whereas Bcl-2 and dysfunctional p53 protein were downregulated,which also contributed to 2-ME2-induced apoptosis.Our findings revealed that 2-ME2 might be a potent natural candidate for chemotherapeutic treatment of human acute T lymphoblastic leukemia when the precise effects of 2-ME2 were investigated further in other T leukemia cell lines and in primary T-cell leukemias.

  1. Effect of digan oral liquid on expression of cell cycle progression and apoptosis-related genes in mice with radiation lesions

    International Nuclear Information System (INIS)

    Objective: To study the effect of Digan oral liquid (DGOL) on expression of cell cycle progression (cyclinD1)- and apoptosis(bcl-2 and bax)- related genes in bone marrow of mice with radiation lesions. Methods: After the radiation lesion model (given 6.0 Gy X-rays once by a linear accelerator) was established, the animals were fed with 0.2ml/10 g of either small dose (100%) or large dose (200%) DGOL twice a day for 8 days. On the ninth day cyclinD1, bcl-2 and bax mRNA expression levels in marrow MNC of model mice were measured by in situ hybridization. Results: In the DGOL group, the bax mRNA expression was significantly decreased (P1 and bcl-2 mRNA were significantly increased (P1 and bcl-2 mRNA expression, and inhibitory effect on bax mRNA expression. In this way, it prevents the blood cells from injury, promotes immunity, and protects the organism. This result provides a theoretical basis for clinical application of Digan oral liquid

  2. Ipl1/Aurora B kinase coordinates synaptonemal complex disassembly with cell cycle progression and crossover formation in budding yeast meiosis

    OpenAIRE

    Jordan, Philip; Copsey, Alice; Newnham, Louise; Kolar, E; Lichten, M; Hoffmann, Eva

    2009-01-01

    Several protein kinases collaborate to orchestrate and integrate cellular and chromosomal events at the G2/M transition in both mitotic and meiotic cells. During the G2/M transition in meiosis, this includes the completion of crossover recombination, spindle formation, and synaptonemal complex (SC) breakdown. We identified Ipl1/Aurora B kinase as the main regulator of SC disassembly. Mutants lacking Ipl1 or its kinase activity assemble SCs with normal timing, but fail to dissociate the centra...

  3. The TAL1/SCL Transcription Factor Regulates Cell Cycle Progression and Proliferation in Differentiating Murine Bone Marrow Monocyte Precursors▿

    OpenAIRE

    Dey, Soumyadeep; Curtis, David J.; Jane, Stephen M.; Brandt, Stephen J.

    2010-01-01

    Monocytopoiesis involves the stepwise differentiation in the bone marrow (BM) of common myeloid precursors (CMPs) to monocytes. The basic helix-loop-helix transcription factor TAL1/SCL plays a critical role in other hematopoietic lineages, and while it had been reported to be expressed by BM-derived macrophages, its role in monocytopoiesis had not been elucidated. Using cell explant models of monocyte/macrophage (MM) differentiation, one originating with CMPs and the other from more committed...

  4. FIN13, a novel growth factor-inducible serine-threonine phosphatase which can inhibit cell cycle progression.

    OpenAIRE

    Guthridge, M A; Bellosta, P; Tavoloni, N; Basilico, C.

    1997-01-01

    We have identified a novel type 2C serine-threonine phosphatase, FIN13, whose expression is induced by fibroblast growth factor 4 and serum in late G1 phase. The protein encoded by FIN13 cDNA includes N- and C-terminal domains with significant homologies to type 2C phosphatases, a domain homologous to collagen, and an acidic domain. FIN13 expression predominates in proliferating tissues. Bacterially expressed FIN13 and FIN13 expressed in mammalian cells exhibit serine-threonine phosphatase ac...

  5. Molecular targeting of prostate cancer cells by a triple drug combination down-regulates integrin driven adhesion processes, delays cell cycle progression and interferes with the cdk-cyclin axis

    International Nuclear Information System (INIS)

    Single drug use has not achieved satisfactory results in the treatment of prostate cancer, despite application of increasingly widespread targeted therapeutics. In the present study, the combined impact of the mammalian target of rapamycin (mTOR)-inhibitor RAD001, the dual EGFr and VGEFr tyrosine kinase inhibitor AEE788 and the histone deacetylase (HDAC)-inhibitor valproic acid (VPA) on prostate cancer growth and adhesion in vitro was investigated. PC-3, DU-145 and LNCaP cells were treated with RAD001, AEE788 or VPA or with a RAD-AEE-VPA combination. Tumor cell growth, cell cycle progression and cell cycle regulating proteins were then investigated by MTT-assay, flow cytometry and western blotting, respectively. Furthermore, tumor cell adhesion to vascular endothelium or to immobilized extracellular matrix proteins as well as migratory properties of the cells was evaluated, and integrin α and β subtypes were analyzed. Finally, effects of drug treatment on cell signaling pathways were determined. All drugs, separately applied, reduced tumor cell adhesion, migration and growth. A much stronger anti-cancer effect was evoked by the triple drug combination. Particularly, cdk1, 2 and 4 and cyclin B were reduced, whereas p27 was elevated. In addition, simultaneous application of RAD001, AEE788 and VPA altered the membranous, cytoplasmic and gene expression pattern of various integrin α and β subtypes, reduced integrin-linked kinase (ILK) and deactivated focal adhesion kinase (FAK). Signaling analysis revealed that EGFr and the downstream target Akt, as well as p70S6k was distinctly modified in the presence of the drug combination. Simultaneous targeting of several key proteins in prostate cancer cells provides an advantage over targeting a single pathway. Since strong anti-tumor properties became evident with respect to cell growth and adhesion dynamics, the triple drug combination might provide progress in the treatment of advanced prostate cancer

  6. Effect of a low-fat fish oil diet on proinflammatory eicosanoids and cell-cycle progression score in men undergoing radical prostatectomy.

    Science.gov (United States)

    Galet, Colette; Gollapudi, Kiran; Stepanian, Sevan; Byrd, Joshua B; Henning, Susanne M; Grogan, Tristan; Elashoff, David; Heber, David; Said, Jonathan; Cohen, Pinchas; Aronson, William J

    2014-01-01

    We previously reported that a 4- to 6-week low-fat fish oil (LFFO) diet did not affect serum insulin-like growth factor (IGF)-1 levels (primary outcome) but resulted in lower omega-6 to omega-3 fatty acid ratios in prostate tissue and lower prostate cancer proliferation (Ki67) as compared with a Western diet. In this post hoc analysis, the effect of the LFFO intervention on serum pro-inflammatory eicosanoids, leukotriene B4 (LTB4) and 15-S-hydroxyeicosatetraenoic acid [15(S)-HETE], and the cell-cycle progression (CCP) score were investigated. Serum fatty acids and eicosanoids were measured by gas chromatography and ELISA. CCP score was determined by quantitative real-time reverse transcriptase PCR (RT-PCR). Associations between serum eicosanoids, Ki67, and CCP score were evaluated using partial correlation analyses. BLT1 (LTB4 receptor) expression was determined in prostate cancer cell lines and prostatectomy specimens. Serum omega-6 fatty acids and 15(S)-HETE levels were significantly reduced, and serum omega-3 levels were increased in the LFFO group relative to the Western diet group, whereas there was no change in LTB4 levels. The CCP score was significantly lower in the LFFO compared with the Western diet group. The 15(S)-HETE change correlated with tissue Ki67 (R = 0.48; P < 0.01) but not with CCP score. The LTB4 change correlated with the CCP score (r = 0.4; P = 0.02) but not with Ki67. The LTB4 receptor BLT1 was detected in prostate cancer cell lines and human prostate cancer specimens. In conclusion, an LFFO diet resulted in decreased 15(S)-HETE levels and lower CCP score relative to a Western diet. Further studies are warranted to determine whether the LFFO diet antiproliferative effects are mediated through the LTB4/BLT1 and 15(S)-HETE pathways. PMID:24169960

  7. Recombinant Actinobacillus actinomycetemcomitans Cytolethal Distending Toxin Proteins Are Required To Interact To Inhibit Human Cell Cycle Progression and To Stimulate Human Leukocyte Cytokine Synthesis

    OpenAIRE

    Akifusa, Sumio; Poole, Stephen; Lewthwaite, Jo; Henderson, Brian; Nair, Sean P

    2001-01-01

    It has recently been discovered that Actinobacillus actinomycetemcomitans, an oral bacterium causing periodontitis, produces cytolethal distending toxin (CDT), a cell cycle-modulating toxin that has three protein subunits: CdtA, CdtB, and CdtC. In this study, we have cloned and expressed each toxin gene from A. actinomycetemcomitans in Escherichia coli and purified the recombinant Cdt proteins to homogeneity. Individual Cdt proteins failed to induce cell cycle arrest of the human epithelial c...

  8. Fuel cell and advanced turbine power cycle

    Energy Technology Data Exchange (ETDEWEB)

    White, D.J. [Solar Turbines, Inc., San Diego, CA (United States)

    1995-10-19

    Solar Turbines, Incorporated (Solar) has a vested interest in the integration of gas turbines and high temperature fuel cells and in particular, solid oxide fuel cells (SOFCs). Solar has identified a parallel path approach to the technology developments needed for future products. The primary approach is to move away from the simple cycle industrial machines of the past and develop as a first step more efficient recuperated engines. This move was prompted by the recognition that the simple cycle machines were rapidly approaching their efficiency limits. Improving the efficiency of simple cycle machines is and will become increasingly more costly. Each efficiency increment will be progressively more costly than the previous step.

  9. A key commitment step in erythropoiesis is synchronized with the cell cycle clock through mutual inhibition between PU.1 and S-phase progression

    NARCIS (Netherlands)

    R. Pop (Ramona); J.R. Shearstone (Jeffrey); Q. Shen (Qichang); Y. Liu (Ying); K. Hallstrom (Kelly); M. Koulnis (Miroslav); J.H. Gribnau (Joost); M. Socolovsky (Merav)

    2010-01-01

    textabstractHematopoietic progenitors undergo differentiation while navigating several cell division cycles, but it is unknown whether these two processes are coupled. We addressed this question by studying erythropoiesis in mouse fetal liver in vivo. We found that the initial upregulation of cell s

  10. Progress on cell cycle control and ocular diseases%细胞周期调控与眼部疾病的关系研究进展

    Institute of Scientific and Technical Information of China (English)

    韩金栋; 颜华

    2013-01-01

    Cell cycle is the most important process for vital alteration.With advanced research on cell cycle and its control mechanism,researchers find that cell cycle control participates in many ocular disease.The study of cell cycle control and ocular diseases not only contributes to a deep understanding of the pathogenesis of ocular disease,but also can provide new methods for preventing and treating some ocular diseases.%细胞周期是生命活动中最重要的过程.随着对细胞周期及其调控机制的深入研究,人们发现细胞周期调控参与众多眼部疾病的发生发展.研究细胞周期调控与眼部疾病的关系,不仅有助于深入理解疾病的发病机制,而且可以为某些眼部疾病的预防和治疗提供新的策略.

  11. 5-AED enhances survival of irradiated mice in a G-CSF-dependent manner, stimulates innate immune cell function, reduces radiation-induced DNA damage and induces genes that modulate cell cycle progression and apoptosis

    International Nuclear Information System (INIS)

    The steroid androst-5-ene-3β, 17β-diol (5-androstenediol, 5-AED) elevates circulating granulocytes and platelets in animals and humans, and enhances survival during the acute radiation syndrome (ARS) in mice and non-human primates. 5-AED promotes survival of irradiated human hematopoietic progenitors in vitro through induction of Nuclear Factor-κB (NFκB)-dependent Granulocyte Colony-Stimulating Factor (G-CSF) expression, and causes elevations of circulating G-CSF and interleukin-6 (IL-6). However, the in vivo cellular and molecular effects of 5-AED are not well understood. The aim of this study was to investigate the mechanisms of action of 5-AED administered subcutaneously (s.c.) to mice 24 h before total body γ- or X-irradiation (TBI). We used neutralizing antibodies, flow cytometric functional assays of circulating innate immune cells, analysis of expression of genes related to cell cycle progression, DNA repair and apoptosis, and assessment of DNA strand breaks with halo-comet assays. Neutralization experiments indicated endogenous G-CSF but not IL-6 was involved in survival enhancement by 5-AED. In keeping with known effects of G-CSF on the innate immune system, s.c. 5-AED stimulated phagocytosis in circulating granulocytes and oxidative burst in monocytes. 5-AED induced expression of both bax and bcl-2 in irradiated animals. Cdkn1a and ddb1, but not gadd45a expression, were upregulated by 5-AED in irradiated mice. S.c. 5-AED administration caused decreased DNA strand breaks in splenocytes from irradiated mice. Our results suggest 5-AED survival enhancement is G-CSF-dependent, and that it stimulates innate immune cell function and reduces radiation-induced DNA damage via induction of genes that modulate cell cycle progression and apoptosis. (author)

  12. Sox17 Promotes Cell Cycle Progression and Inhibits TGF-β/Smad3 Signaling to Initiate Progenitor Cell Behavior in the Respiratory Epithelium

    OpenAIRE

    Lange, Alexander W.; Keiser, Angela R.; Wells, James M.; Zorn, Aaron M; Whitsett, Jeffrey A.

    2009-01-01

    The Sry-related high mobility group box transcription factor Sox17 is required for diverse developmental processes including endoderm formation, vascular development, and fetal hematopoietic stem cell maintenance. Expression of Sox17 in mature respiratory epithelial cells causes proliferation and lineage respecification, suggesting that Sox17 can alter adult lung progenitor cell fate. In this paper, we identify mechanisms by which Sox17 influences lung epithelial progenitor cell behavior and ...

  13. Stroma-Derived Connective Tissue Growth Factor Maintains Cell Cycle Progression and Repopulation Activity of Hematopoietic Stem Cells In Vitro

    OpenAIRE

    Rouzanna Istvánffy; Baiba Vilne; Christina Schreck; Franziska Ruf; Charlotta Pagel; Sandra Grziwok; Lynette Henkel; Olivia Prazeres da Costa; Johannes Berndt; Volker Stümpflen; Katharina S. Götze; Matthias Schiemann; Christian Peschel; Hans-Werner Mewes; Oostendorp, Robert A.J.

    2015-01-01

    Summary Hematopoietic stem cells (HSCs) are preserved in co-cultures with UG26-1B6 stromal cells or their conditioned medium. We performed a genome-wide study of gene expression changes of UG26-1B6 stromal cells in contact with Lineage− SCA-1+ KIT+ (LSK) cells. This analysis identified connective tissue growth factor (CTGF) to be upregulated in response to LSK cells. We found that co-culture of HSCs on CTGF knockdown stroma (shCtgf) shows impaired engraftment and long-term quality. Further ex...

  14. Akt/Protein Kinase B-Dependent Phosphorylation and Inactivation of WEE1Hu Promote Cell Cycle Progression at G2/M Transition

    OpenAIRE

    Katayama, Kazuhiro; Fujita, Naoya; Tsuruo, Takashi

    2005-01-01

    The serine/threonine kinase Akt is known to promote cell growth by regulating the cell cycle in G1 phase through activation of cyclin/Cdk kinases and inactivation of Cdk inhibitors. However, how the G2/M phase is regulated by Akt remains unclear. Here, we show that Akt counteracts the function of WEE1Hu. Inactivation of Akt by chemotherapeutic drugs or the phosphatidylinositide-3-OH kinase inhibitor LY294002 induced G2/M arrest together with the inhibitory phosphorylation of Cdc2. Because the...

  15. UV-induced changes in cell cycle and gene expression within rabbit lens epithelial cells

    Energy Technology Data Exchange (ETDEWEB)

    Sidjanin, D. [Northern Illinois Univ., De Kalb, IL (United States). Dept. of Biological Sciences; Grdina, D. [Argonne National Lab., IL (United States); Woloschak, G.E. [Northern Illinois Univ., De Kalb, IL (United States). Dept. of Biological Sciences

    1994-11-01

    Damage to lens epithelial cells is a probable initiation process in cataract formation induced by ultraviolet radiation. These experiments investigated the ability of 254 nm radiation on cell cycle progression and gene expression in rabbit lens epithelial cell line N/N1003A. No changes in expression of c-fos, c-jun, alpha- tubulin, or vimentin was observed following UV exposure. Using flow cytometry, an accumulation of cells in G1/S phase of the cell cycle 1 hr following exposure. The observed changes in gene expression, especially the decreased histone transcripts reported here may play a role in UV induced inhibition of cell cycle progression.

  16. 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.

  17. Molecular biological mechanism II. Molecular mechanisms of cell cycle regulation

    International Nuclear Information System (INIS)

    The cell cycle in eukaryotes is regulated by central cell cycle controlling protein kinase complexes. These protein kinase complexes consist of a catalytic subunit from the cyclin-dependent protein kinase family (CDK), and a regulatory subunit from the cyclin family. Cyclins are characterised by their periodic cell cycle related synthesis and destruction. Each cell cycle phase is characterised by a specific set of CDKs and cyclins. The activity of CDK/cyclin complexes is mainly regulated on four levels. It is controlled by specific phosphorylation steps, the synthesis and destruction of cyclins, the binding of specific inhibitor proteins, and by active control of their intracellular localisation. At several critical points within the cell cycle, named checkpoints, the integrity of the cellular genome is monitored. If damage to the genome or an unfinished prior cell cycle phase is detected, the cell cycle progression is stopped. These cell cycle blocks are of great importance to secure survival of cells. Their primary importance is to prevent the manifestation and heritable passage of a mutated genome to daughter cells. Damage sensing, DNA repair, cell cycle control and apoptosis are closely linked cellular defence mechanisms to secure genome integrity. Disregulation in one of these defence mechanisms are potentially correlated with an increased cancer risk and therefore in at least some cases with an increased radiation sensitivity. (orig.)

  18. Loss of Expression of Reprimo, a p53-induced Cell Cycle Arrest Gene, Correlates with Invasive Stage of Tumor Progression and p73 Expression in Gastric Cancer.

    Directory of Open Access Journals (Sweden)

    Kathleen Saavedra

    Full Text Available Reprimo (RPRM, a downstream effector of p53-induced cell cycle arrest at G2/M, has been proposed as a putative tumor suppressor gene (TSG and as a potential biomarker for non-invasive detection of gastric cancer (GC. The aim of this study was to evaluate the epigenetic silencing of RPRM gene by promoter methylation and its tumor suppressor function in GC cell lines. Furthermore, clinical significance of RPRM protein product and its association with p53/p73 tumor suppressor protein family was explored. Epigenetic silencing of RPRM gene by promoter methylation was evaluated in four GC cell lines. Protein expression of RPRM was evaluated in 20 tumor and non-tumor matched cases. The clinical significance of RPRM association with p53/p73 tumor suppressor protein family was assessed in 114 GC cases. Tumor suppressor function was examined through functional assays. RPRM gene expression was negatively correlated with promoter methylation (Spearman rank r = -1; p = 0.042. RPRM overexpression inhibited colony formation and anchorage-independent growth. In clinical samples, RPRM gene protein expression was detected in 75% (15/20 of non-tumor adjacent mucosa, but only in 25% (5/20 of gastric tumor tissues (p = 0.001. Clinicopathological correlations of loss of RPRM expression were significantly associated with invasive stage of GC (stage I to II-IV, p = 0.02 and a positive association between RPRM and p73 gene protein product expression was found (p<0.0001 and kappa value = 0.363. In conclusion, epigenetic silencing of RPRM gene by promoter methylation is associated with loss of RPRM expression. Functional assays suggest that RPRM behaves as a TSG. Loss of expression of RPRM gene protein product is associated with the invasive stage of GC. Positive association between RPRM and p73 expression suggest that other members of the p53 gene family may participate in the regulation of RPRM expression.

  19. K-Ras-Independent Effects of the Farnesyl Transferase Inhibitor L-744,832 on Cyclin B1/Cdc2 Kinase Activity, G2/M Cell Cycle Progression and Apoptosis in Human Pancreatic Ductal Adenocarcinoma Cell

    Directory of Open Access Journals (Sweden)

    Si Young Song

    2000-05-01

    Full Text Available Pancreatic ductal adenocarcinoma is a highly lethal malignancy that is resistant to traditional cytotoxic therapy. High rates of activating codon 12 K-Ras mutations in this disease have generated considerable interest in the therapeutic application of novel farnesyl transferase inhibitors (FTIs. However, a comprehensive analysis of the effects of FTI treatment on pancreatic cancer cells has not been performed. Treatment of five different human pancreatic cancer cell lines with FTI L744,832 resulted in inhibition of anchorage-dependent growth, with wide variation in sensitivity among different lines. Effective growth inhibition by L-744,832 correlated with accumulation of cells with a tetraploid (4N DNA content and high levels of cyclin B1/cdc2 kinase activity, implying cell cycle arrest downstream from the DNA damage -inducible G2/M cell cycle checkpoint. In addition, sensitive cell lines underwent apoptosis as evidenced by changes in nuclear morphology and internucleosomal DNA fragmentation. L-744,832 at a concentration of 1 µM additively enhanced the cytotoxic effect of ionizing radiation, apparently by overriding G2/M checkpoint activation. The effects of FTI treatment on cell growth and cell cycle regulation were associated with changes in posttranslational processing of H-Ras and N-Ras, but not K-Ras. The results confirm the potential therapeutic efficacy of FTI treatment in pancreatic cancer, and suggest that farnesylated proteins other than K-Ras may act as important regulators of G2/M cell cycle kinetics.

  20. Control of the proper cell cycle progression by products of the tumor suppressor gene p53 and inhibitors of cyclin-dependent kinases. Use of pharmacological inhibitors mimicking the action of cell cycle regulators for cancer therapy

    Czech Academy of Sciences Publication Activity Database

    Wesierska-Gadek, J.; Maurer, M.; Komina, O.; Kramer, M.P.; Wandl, S.; Kryštof, Vladimír; Schmid, G.

    Kerala : Research Signpost, 2008 - (Yoshida, K.), s. 31-74 ISBN 978-81-308-0274-9 R&D Projects: GA ČR GA204/08/0511 Institutional research plan: CEZ:AV0Z50380511 Keywords : cyclin-dependent kinase * tumor suppressor genes * malignant cells Subject RIV: EB - Genetics ; Molecular Biology

  1. Delayed cell cycle progression in selenoprotein W depleted cells is regulated by a mitogen-activated protein kinase kinase 4–p38–p53 pathway

    Science.gov (United States)

    Selenoprotein W (SEPW1) is a ubiquitous, highly conserved thioredoxin-like protein whose depletion causes a p53- and p21Cip1-dependent G1-phase cell cycle arrest in breast and prostate epithelial cells. SEPW1 depletion increases phosphorylation of Ser33 in p53, which is associated with decreased p53...

  2. Recovery and cycle progression in multicell spheroids after fractionated γ-irradiation and combined hyperthermic treatment

    International Nuclear Information System (INIS)

    Spheroids of V79 cells were subjected to fractionated irradiation with two doses of γ-radiation. In addition, a two hours hyperthermic treatment at 420C immediately following the first dose was applied. Cycling and resting cells of this in-vitro tumour model were then assayed for survival as function of the fractionation interval. In parallel, changes in cycle progression between the doses were measured by means of cytofluorometry. As main proliferative effects induced by this combined radiation and heat treatment transient S-phase blocking of cycling and recruitment of resting cells were observed. The split-dose survival curve displayed considerable synergistic action of heat and radiation and a six hours delay of Elkind-recoverey in both cycling and resting cells. (orig.)

  3. STAGE-DEPENDENCE, SEASONAL CHANGES AND EFFECTS OF CADMIUM ON CELL CYCLE AND APOPTOTIC ACTIVITIES DURING THE SPERMATOGENIC PROGRESSION IN THE DOGFISH SHARK (SQUALUS ACANTHIAS). (R825434)

    Science.gov (United States)

    The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Concl...

  4. Creatine kinase in cell cycle regulation and cancer.

    Science.gov (United States)

    Yan, Yong-Bin

    2016-08-01

    The phosphocreatine-creatine kinase (CK) shuttle system is increasingly recognized as a fundamental mechanism for ATP homeostasis in both excitable and non-excitable cells. Many intracellular processes are ATP dependent. Cell division is a process requiring a rapid rate of energy turnover. Cell cycle regulation is also a key point to understanding the mechanisms underlying cancer progression. It has been known for about 40 years that aberrant CK levels are associated with various cancers and for over 30 years that CK is involved in mitosis regulation. However, the underlying molecular mechanisms have not been investigated sufficiently until recently. By maintaining ATP at sites of high-energy demand, CK can regulate cell cycle progression by affecting the intracellular energy status as well as by influencing signaling pathways that are essential to activate cell division and cytoskeleton reorganization. Aberrant CK levels may impair cell viability under normal or stressed conditions and induce cell death. The involvement of CK in cell cycle regulation and cellular energy metabolism makes it a potential diagnostic biomarker and therapeutic target in cancer. To understand the multiple physiological/pathological functions of CK, it is necessary to identify CK-binding partners and regulators including proteins, non-coding RNAs and participating endogenous small molecular weight chemical compounds. This review will focus on molecular mechanisms of CK in cell cycle regulation and cancer progression. It will also discuss the implications of recent mechanistic studies, the emerging problems and future challenges of the multifunctional enzyme CK. PMID:27020776

  5. Cell cycle and DNA repair in UV-irradiated cells of mouse neuroblastoma

    International Nuclear Information System (INIS)

    A correlation has been shown between a reduced rate of movement of UV-irradiated neuroblastoma cells from G1 into S phase, an essential increase of cells in S phase while progressing through the cell cycle, and a defect in free DNA synthesis on a damaged template. These indices may reflect one and the same cell response to the UV light

  6. SKLB70326, a novel small-molecule inhibitor of cell-cycle progression, induces G{sub 0}/G{sub 1} phase arrest and apoptosis in human hepatic carcinoma cells

    Energy Technology Data Exchange (ETDEWEB)

    Han, Yuanyuan; He, Haiyun [State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, West China Medical School, Sichuan University, Chengdu 610041 (China); Peng, Feng [Department of Thoracic Oncology of the Cancer Center and State Key Laboratory of Biotherapy, West China Hospital, West China Medical School, Sichuan University, Chengdu 610041 (China); Liu, Jiyan; Dai, Xiaoyun; Lin, Hongjun; Xu, Youzhi; Zhou, Tian; Mao, Yongqiu; Xie, Gang; Yang, Shengyong; Yu, Luoting; Yang, Li [State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, West China Medical School, Sichuan University, Chengdu 610041 (China); Zhao, Yinglan, E-mail: alancenxb@sina.com [State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, West China Medical School, Sichuan University, Chengdu 610041 (China)

    2012-05-18

    Highlights: Black-Right-Pointing-Pointer SKLB70326 is a novel compound and has activity of anti-HCC. Black-Right-Pointing-Pointer SKLB70326 induces cell cycle arrest and apoptosis in HepG2 cells. Black-Right-Pointing-Pointer SKLB70326 induces G{sub 0}/G{sub 1} phase arrest via inhibiting the activity of CDK2, CDK4 and CDK6. Black-Right-Pointing-Pointer SKLB70326 induces apoptosis through the intrinsic pathway. -- Abstract: We previously reported the potential of a novel small molecule 3-amino-6-(3-methoxyphenyl)thieno[2.3-b]pyridine-2-carboxamide (SKLB70326) as an anticancer agent. In the present study, we investigated the anticancer effects and possible mechanisms of SKLB70326 in vitro. We found that SKLB70326 treatment significantly inhibited human hepatic carcinoma cell proliferation in vitro, and the HepG2 cell line was the most sensitive to its treatment. The inhibition of cell proliferation correlated with G{sub 0}/G{sub 1} phase arrest, which was followed by apoptotic cell death. The SKLB70326-mediated cell-cycle arrest was associated with the downregulation of cyclin-dependent kinase (CDK) 2, CDK4 and CDK6 but not cyclin D1 or cyclin E. The phosphorylation of the retinoblastoma protein (Rb) was also observed. SKLB70326 treatment induced apoptotic cell death via the activation of PARP, caspase-3, caspase-9 and Bax as well as the downregulation of Bcl-2. The expression levels of p53 and p21 were also induced by SKLB70326 treatment. Moreover, SKLB70326 treatment was well tolerated. In conclusion, SKLB70326, a novel cell-cycle inhibitor, notably inhibits HepG2 cell proliferation through the induction of G{sub 0}/G{sub 1} phase arrest and subsequent apoptosis. Its potential as a candidate anticancer agent warrants further investigation.

  7. P27 in cell cycle control and cancer

    DEFF Research Database (Denmark)

    Møller, Michael Boe

    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...... distinct NHL entities however, shortened survival seems to correlate with high expression of p27. For definitive assessment of the role played by p27 in lymphomagenesis, and the prognostic value of p27 in these tumors, further studies of distinct NHL entities are needed. This review addresses the function...

  8. The tumor suppressor SirT2 regulates cell cycle progression and genome stability by modulating the mitotic deposition of H4K20 methylation

    Science.gov (United States)

    The establishment of the epigenetic mark H4K20me1 (monomethylation of H4K20) by PR-Set7 during G2/M directly impacts S-phase progression and genome stability. However, the mechanisms involved in the regulation of this event are not well understood. Here we show that SirT2 regulates H4K20me1 depositi...

  9. Feedback and Modularity in Cell Cycle Control

    Science.gov (United States)

    Skotheim, Jan

    2009-03-01

    Underlying the wonderful diversity of natural forms is the ability of an organism to grow into its appropriate shape. Regulation ensures that cells grow, divide and differentiate so that the organism and its constitutive parts are properly proportioned and of suitable size. Although the size-control mechanism active in an individual cell is of fundamental importance to this process, it is difficult to isolate and study in complex multi-cellular systems and remains poorly understood. This motivates our use of the budding yeast model organism, whose Start checkpoint integrates multiple internal (e.g. cell size) and external signals into an irreversible decision to enter the cell cycle. We have endeavored to address the following two questions: What makes the Start transition irreversible? How does a cell compute its own size? I will report on the progress we have made. Our work is part of an emerging framework for understanding biological control circuits, which will allow us to discern the function of natural systems and aid us in engineering synthetic systems.

  10. Progress and Future Directions in North American Carbon Cycle Science

    Science.gov (United States)

    Michalak, Anna; Huntzinger, Deborah; Shrestha, Gyami

    2013-05-01

    The North American Carbon Program (NACP) convened its fourth biennial "All Investigators" meeting (AIM4, http://www.nacarbon.org/meeting_2013) to review progress in understanding the dynamics of the carbon cycle of North America and adjacent oceans and to chart a course for a more integrative and holistic approach to future research. The meeting was structured around the six decadal goals outlined in the new "A U.S. Carbon Cycle Science Plan" (Michalak et al., University Corporation for Atmospheric Research, 2011, available at http://www.carboncyclescience.gov) and focused on (1) diagnosis of the atmospheric carbon cycle, (2) drivers of anthropogenic emissions, (3) vulnerability of carbon stocks to change, (4) ecosystem impacts of change, (5) carbon management, and (6) decision support.

  11. Cell cycle related /sup 125/IUDR-induced-division delay

    International Nuclear Information System (INIS)

    A series of experiments were run to determine if /sup 125/I-decays, in /sup 125/IUdR labeled DNA, specifically accumulated at 1, 3, 5, 7 and 9 hours after plating labeled mitotic cells caused a change in the rate or time of cell entry into mitosis. To accomplish this, a pool of labeled mitotic cells was selected in mitosis and plated in replicate flasks. /sup 125/I decays were accumulated in groups of cells by cooling (40C) for 2 hours starting at the designated times. After rewarding, colcemid was added to arrest cells in mitosis. The rate of cell progression into mitosis for each cell cycle time of accumulation was determined by scoring the mitotic index of cells sampled as a function of time after addition of the colcemid. The results are summarized: (1) Decays from /sup 125/I in /sup 125/I(UdR) labeled DNA reduced the rate of cell progression into mitosis and delayed the time of initiation of mitosis. (2) The reduced rate of progression and the delayed time of initiation of mitosis were independent of the cell cycle time that /sup 125/I-decays were accumulated. (3) The reduced rate of progression after cell cycle accumulation of /sup 125/I decay was statistically indistinguishable from the corresponding controls. (4) The delayed initiation of mitosis after specific cell cycle accumulation of /sup 125/I- decays was greater than the corresponding control. The relationship of these data to DNA and non-DNA division delay target(s) is emphasized

  12. Systems Level Modeling of the Cell Cycle Using Budding Yeast

    Directory of Open Access Journals (Sweden)

    D.R. Kim

    2007-01-01

    Full Text Available Proteins involved in the regulation of the cell cycle are highly conserved across all eukaryotes, and so a relatively simple eukaryote such as yeast can provide insight into a variety of cell cycle perturbations including those that occur in human cancer. To date, the budding yeast Saccharomyces cerevisiae has provided the largest amount of experimental and modeling data on the progression of the cell cycle, making it a logical choice for in-depth studies of this process. Moreover, the advent of methods for collection of high-throughput genome, transcriptome, and proteome data has provided a means to collect and precisely quantify simultaneous cell cycle gene transcript and protein levels, permitting modeling of the cell cycle on the systems level. With the appropriate mathematical framework and suffi cient and accurate data on cell cycle components, it should be possible to create a model of the cell cycle that not only effectively describes its operation, but can also predict responses to perturbations such as variation in protein levels and responses to external stimuli including targeted inhibition by drugs. In this review, we summarize existing data on the yeast cell cycle, proteomics technologies for quantifying cell cycle proteins, and the mathematical frameworks that can integrate this data into representative and effective models. Systems level modeling of the cell cycle will require the integration of high-quality data with the appropriate mathematical framework, which can currently be attained through the combination of dynamic modeling based on proteomics data and using yeast as a model organism.

  13. Ethanol extract of Innotus obliquus (Chaga mushroom) induces G1 cell cycle arrest in HT-29 human colon cancer cells

    OpenAIRE

    Lee, Hyun Sook; Kim, Eun Ji; Kim, Sun Hyo

    2015-01-01

    BACKGROUND/OBJECTIVES Inonotus obliquus (I. obliquus, Chaga mushroom) has long been used as a folk medicine to treat cancer. In the present study, we examined whether or not ethanol extract of I. obliquus (EEIO) inhibits cell cycle progression in HT-29 human colon cancer cells, in addition to its mechanism of action. MATERIALS/METHODS To examine the effects of Inonotus obliquus on the cell cycle progression and the molecular mechanism in colon cancer cells, HT-29 human colon cancer cells were...

  14. Assaying Cell Cycle Status Using Flow Cytometry.

    Science.gov (United States)

    Kim, Kang Ho; Sederstrom, Joel M

    2015-01-01

    In this unit, two protocols are described for analyzing cell cycle status using flow cytometry. The first is based on the simultaneous analysis of proliferation-specific marker (Ki-67) and cellular DNA content, which discriminate resting/quiescent cell populations (G0 cell) and quantify cell cycle distribution (G1, S, or G2/M), respectively. The second is based on differential staining of DNA and RNA through co-staining of Hoechst 33342 and Pyronin Y, which is also useful to identify G0 cells from G1 cells. Along with these methods for analyzing cell cycle status, two additional methods for cell proliferation assays with recent updates of newly developed fluorophores, which allow multiplex analysis of cell cycle status, cell proliferation, and a gene of interest using flow cytometry, are outlined. PMID:26131851

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

    DEFF Research Database (Denmark)

    Oleksiewicz, M.B.; Alexandersen, Søren

    1997-01-01

    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 cyc...

  16. 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.

  17. Cell cycle control of DNA joint molecule resolution.

    Science.gov (United States)

    Wild, Philipp; Matos, Joao

    2016-06-01

    The establishment of stable interactions between chromosomes underpins vital cellular processes such as recombinational DNA repair and bipolar chromosome segregation. On the other hand, timely disengagement of persistent connections is necessary to assure efficient partitioning of the replicated genome prior to cell division. Whereas great progress has been made in defining how cohesin-mediated chromosomal interactions are disengaged as cells prepare to undergo chromosome segregation, little is known about the metabolism of DNA joint molecules (JMs), generated during the repair of chromosomal lesions. Recent work on Mus81 and Yen1/GEN1, two conserved structure-selective endonucleases, revealed unforeseen links between JM-processing and cell cycle progression. Cell cycle kinases and phosphatases control Mus81 and Yen1/GEN1 to restrain deleterious JM-processing during S-phase, while safeguarding chromosome segregation during mitosis. PMID:26970388

  18. Cell cycle control after DNA damage: arrest, recovery and adaptation

    International Nuclear Information System (INIS)

    DNA damage triggers surveillance mechanisms, the DNA checkpoints, that control the genome integrity. The DNA checkpoints induce several responses, either cellular or transcriptional, that favor DNA repair. In particular, activation of the DNA checkpoints inhibits cell cycle progression in all phases, depending on the stage when lesions occur. These arrests are generally transient and cells ultimately reenter the cell division cycle whether lesions have been repaired (this process is termed 'recovery') or have proved un-repairable (this option is called 'adaptation'). The mechanisms controlling cell cycle arrests, recovery and adaptation are largely conserved among eukaryotes, and much information is now available for the yeast Saccharomyces cerevisiae, that is used as a model organism in these studies. (author)

  19. Ras signalling linked to the cell-cycle machinery by the retinoblastoma protein

    NARCIS (Netherlands)

    Peeper, D.S.; Upton, T.M.; Ladha, M.H.; Neuman, E.; Zalvide, J.; Bernards, R.A.; DeCaprio, J.A.; Ewen, M.E.

    1997-01-01

    The Ras proto-oncogene is a central component of mitogenic signal-transduction pathways, and is essential for cells both to leave a quiescent state (GO) and to pass through the GI/S transition of the cell cycle. The mechanism by which Ras signalling regulates cell-cycle progression is unclear, howev

  20. Identification of Cell Cycle-regulated Genes in Fission YeastD⃞

    OpenAIRE

    Peng, Xu; Karuturi, R Krishna Murthy; Miller, Lance D.; Lin, Kui; Jia, Yonghui; Kondu, Pinar; Wang, Long; Wong, Lim-Soon; Liu, Edison T.; Balasubramanian, Mohan K.; Liu, Jianhua

    2005-01-01

    Cell cycle progression is both regulated and accompanied by periodic changes in the expression levels of a large number of genes. To investigate cell cycle-regulated transcriptional programs in the fission yeast Schizosaccharomyces pombe, we developed a whole-genome oligonucleotide-based DNA microarray. Microarray analysis of both wild-type and cdc25 mutant cell cultures was performed to identify transcripts whose levels oscillated during the cell cycle. Using an unsupervised algorithm, we id...

  1. Cell Cycle Deregulation in Ewing's Sarcoma Pathogenesis

    Directory of Open Access Journals (Sweden)

    Ashley A. Kowalewski

    2011-01-01

    Full Text Available Ewing's sarcoma is a highly aggressive pediatric tumor of bone that usually contains the characteristic chromosomal translocation t(11;22(q24;q12. This translocation encodes the oncogenic fusion protein EWS/FLI, which acts as an aberrant transcription factor to deregulate target genes necessary for oncogenesis. One key feature of oncogenic transformation is dysregulation of cell cycle control. It is therefore likely that EWS/FLI and other cooperating mutations in Ewing's sarcoma modulate the cell cycle to facilitate tumorigenesis. This paper will summarize current published data associated with deregulation of the cell cycle in Ewing's sarcoma and highlight important questions that remain to be answered.

  2. Cell cycle phases in the unequal mother/daughter cell cycles of Saccharomyces cerevisiae.

    OpenAIRE

    Brewer, B J; Chlebowicz-Sledziewska, E; Fangman, W L

    1984-01-01

    During cell division in the yeast Saccharomyces cerevisiae mother cells produce buds (daughter cells) which are smaller and have longer cell cycles. We performed experiments to compare the lengths of cell cycle phases in mothers and daughters. As anticipated from earlier indirect observations, the longer cell cycle time of daughter cells is accounted for by a longer G1 interval. The S-phase and the G2-phase are of the same duration in mother and daughter cells. An analysis of five isogenic st...

  3. Sonic Hedgehog Opposes Epithelial Cell Cycle Arrest

    OpenAIRE

    Fan, Hongran; Khavari, Paul A

    1999-01-01

    Stratified epithelium displays an equilibrium between proliferation and cell cycle arrest, a balance that is disrupted in basal cell carcinoma (BCC). Sonic hedgehog (Shh) pathway activation appears sufficient to induce BCC, however, the way it does so is unknown. Shh-induced epidermal hyperplasia is accompanied by continued cell proliferation in normally growth arrested suprabasal cells in vivo. Shh-expressing cells fail to exit S and G2/M phases in response to calcium-induced differentiation...

  4. Progress in carbonate fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Krumpelt, M.; Roche, M.F.

    1995-08-01

    Our objective is to increase both the life and power of the molten carbonate fuel cell (MCFC) by developing improved components and designs. Current activities are as follows: (1) Development of lithium ferrate (LiFeO{sub 2}) and lithium cobaltate (LiCoO{sub 2}) cathodes for extended MCFC life, particularly in pressurized operation, where the present cathode, NiO, provides insufficient life; (2) Development of distributed-manifold MCFC designs for increased volumetric power density and decreased temperature gradients (and, therefore, increased life); (3) Development of components and designs appropriate for high-power-density operation (>2 kW/m{sup 2} and >100 kW/m{sup 3} in an integrated MCFC system); and (4) Studies of pitting corrosion of the stainless-steel interconnects and aluminized seals now being employed in the MCFC (alternative components will also be studied). Each of these activities has the potential to reduce the MCFC system cost significantly. Progress in each activity will be presented during the poster session.

  5. Polyamines and the Cell Cycle of Catharanthus roseus Cells in Culture 1

    Science.gov (United States)

    Maki, Hisae; Ando, Satoshi; Kodama, Hiroaki; Komamine, Atsushi

    1991-01-01

    Investigation was made on the effect of partial depletion of polyamines (PAs), induced by treatment with inhibitors of the biosynthesis of PAs, on the distribution of cells at each phase of the cell cycle in Catharanthus roseus (L.) G. Don. cells in suspension cultures, using flow cytometry. More cells treated with inhibitors of arginine decarboxylase (ADC) and ornithine decarboxylase (ODC) were accumulated in the G1 phase than those in the control, while the treatment with an inhibitor of spermidine (SPD) synthase showed no effect on the distribution of cells. The endogenous levels of the PAs, putrescine (PUT), SPD, and spermine (SPM), were determined during the cell cycle in synchronous cultures of C. roseus. Two peaks of endogenous level of PAs, in particular, of PUT and SPD, were observed during the cell cycle. Levels of PAs increased markedly prior to synthesis of DNA in the S phase and prior to cytokinesis. Activities of ADC and ODC were also assayed during the cell cycle. Activities of ADC was much higher than that of ODC throughout the cell cycle, but both activities of ODC and ADC changed in concert with changes in levels of PAs. Therefore, it is suggested that these enzymes may regulate PA levels during the cell cycle. These results indicate that inhibitors of PUT biosynthesis caused the suppression of cell proliferation by prevention of the progression of the cell cycle, probably from the G1 to the S phase, and PUT may play more important roles in the progression of the cell cycle than other PAs. PMID:16668290

  6. Cell cycle effects for radiosensitivity after heavy ion exposure

    International Nuclear Information System (INIS)

    In order to study the relative contribution of the two major DNA double-strand break (DSB) repair pathways, non-homologous end-joining (NHEJ) and homologous recombinational repair (HRR), to the repair of DSBs and non-DSB clustered DNA damage induced by high linear energy transfer (LET) ionizing radiation through the cell cycle, we exposed wild type (WT), NHEJ-deficient, and HRR-deficient Chinese hamster ovary (CHO) cells synchronized by mitotic shake-off to accelerated heavy ions and X-rays. The cell cycle-dependent variation in survival observed in WT cells after X-irradiation was not observed after exposure to 500 MeV/amu iron ions. Non-homologous end joining (NHEJ) and homologous recombinational repair (HRR)-defective cells showed different patterns of cell cycle-dependent radiosensitivity after X-irradiation compared to WT cells, that were likewise significantly attenuated after iron ion exposures. Higher relative biological effectiveness for several other accelerated heavy ions (C, Ne, Si, Ar) of differing LETs was observed for cells exposed in S phase compared to cells exposed in G1. We also observed that HRR deficiency, unlike NHEJ deficiency, did not affect the progression of irradiated G2 cells into mitosis, thus contributing to increased cell killing observed in G2-phase HRR-deficient cells. The HRR-deficient cells showed significantly increased levels of chromatid-type aberrations that correlated with their cell cycle pattern of survival after both X- and iron ion irradiation. Our results suggest that high LET radiation produces not only complex DSBs but also complex non-DSB clustered lesions that specifically require the HRR-mediated repair of these lesions if encountered during DNA replication. In this year, we focused on Fanconi Anemia DNA repair pathway. Only FancA mutant cells showed hypersensitivity to high LET ionizing radiation among other FancC, FancD1, FancD2, and FancG mutant cells. (author)

  7. Research progress of socio-economic water cycle in China

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    China has made great progress in the study of socio-economic water cycle. She has completed national water resources appraisement and medium to long-term water supply planning. She has been engaging in study on water-deficient regions in North China and Northwest China for about half a century. For solving water shortage problem in northern China, she has put forward the famous South-to-North Water Transferring Projects, which has been set as one of the four biggest national projects in the Tenth Five-Year-Plan period although there are still debates. For promoting water use efficiency, China has been reforming her water management system, including water right system and water price system. There has already been a case of water right purchase. China has also done a lot of research on the interaction between human activity, water and ecosystem. For meeting the need of sustainability and coordinating water resources development and environmental protection, the study of ecological water requirement became very hot in recent years. There are three focuses of socio-economic water cycle study now in China: water transfer projects from the south to the north, water resources management and ecological water requirement.

  8. Meiotic and Mitotic Cell Cycle Mutants Involved in Gametophyte Development in Arabidopsis

    Institute of Scientific and Technical Information of China (English)

    Jingjing Liu; Li-Jia Qu

    2008-01-01

    The alternation between diploid and haploid generations is fundamentalin the life cycles of both animals and plants.The meiotic cell cycle is common to both animals and plants gamete formation, but in animals the products of meiosis are gametes,whereas for most plants,subsequent mitotic cell cycles are needed for their formation. Clarifying the regulatory mechanisms of mitotic cell cycle progression during gametophyte development will help understanding of sexual reproduction in plants.Many mutants defective in gametophyte development and,in particular,many meiotic and mitotic cell cycle mutants in Arabidopsis male and female gametophyte development were identified through both forward and reverse genetics approaches.

  9. A cell cycle and nutritional checkpoint controlling bacterial surface adhesion.

    Directory of Open Access Journals (Sweden)

    Aretha Fiebig

    2014-01-01

    Full Text Available In natural environments, bacteria often adhere to surfaces where they form complex multicellular communities. Surface adherence is determined by the biochemical composition of the cell envelope. We describe a novel regulatory mechanism by which the bacterium, Caulobacter crescentus, integrates cell cycle and nutritional signals to control development of an adhesive envelope structure known as the holdfast. Specifically, we have discovered a 68-residue protein inhibitor of holdfast development (HfiA that directly targets a conserved glycolipid glycosyltransferase required for holdfast production (HfsJ. Multiple cell cycle regulators associate with the hfiA and hfsJ promoters and control their expression, temporally constraining holdfast development to the late stages of G1. HfiA further functions as part of a 'nutritional override' system that decouples holdfast development from the cell cycle in response to nutritional cues. This control mechanism can limit surface adhesion in nutritionally sub-optimal environments without affecting cell cycle progression. We conclude that post-translational regulation of cell envelope enzymes by small proteins like HfiA may provide a general means to modulate the surface properties of bacterial cells.

  10. Cell cycle effects for radiosensitivity after heavy ion exposure

    International Nuclear Information System (INIS)

    In order to study the relative contribution of the two major DNA double-strand break (DSB) repair pathways, non-homologous end-joining (NHEJ) and homologous recombinational repair (HRR), to the repair of DSBs and non-DSB clustered DNA damage induced by high linear energy transfer (LET) ionizing radiation through the cell cycle, we exposed wild type (WT), NHEJ-deficient, and HRR-deficient Chinese hamster ovary (CHO) cells synchronized by mitotic shake-off to accelerated heavy ions and X-rays. The cell cycle-dependent variation in survival observed in WT cells after X-irradiation was not observed after exposure to 500 MeV/amu iron ions. Non-homologous end joining (NHEJ) and homologous recombinational repair (HRR)-defective cells showed different patterns of cell cycle-dependent radiosensitivity after X-irradiation compared to WT cells, that were likewise significantly attenuated after iron ion exposures. Higher relative biological effectiveness for several other accelerated heavy ions (C, Ne, Si, Ar) of differing LETs was observed for cells exposed in S phase compared to cells exposed in G1. We also observed that HRR deficiency, unlike NHEJ deficiency, did not affect the progression of irradiated G2 cells into mitosis, thus contributing to increased cell killing observed in G2-phase HRR-deficient cells. The HRR-deficient cells showed significantly increased levels of chromatid-type aberrations that correlated with their cell cycle pattern of survival after both X- and iron ion irradiation. Our results suggest that high LET radiation produces not only complex DSBs but also complex non-DSB clustered lesions that specifically require the HRR-mediated repair of these lesions if encountered during DNA replication. (author)

  11. The cell cycle and acute kidney injury

    OpenAIRE

    Price, Peter M.; Safirstein, Robert L.; Megyesi, Judit

    2009-01-01

    Acute kidney injury (AKI) activates pathways of cell death and cell proliferation. Although seemingly discrete and unrelated mechanisms, these pathways can now be shown to be connected and even to be controlled by similar pathways. The dependence of the severity of renal-cell injury on cell cycle pathways can be used to control and perhaps to prevent acute kidney injury. This review is written to address the correlation between cellular life and death in kidney tubules, especially in acute ki...

  12. The role of the cell cycle machinery in resumption of postembryonic development

    NARCIS (Netherlands)

    Barroco, R.M.; Poucke, van K.; Bergervoet, J.H.W.; Veylder, de L.; Groot, S.P.C.; Inze, D.; Engler, G.

    2005-01-01

    Cell cycle activity is required for plant growth and development, but its involvement in the early events that initiate seedling development remains to be clarified. We performed experiments aimed at understanding when cell cycle progression is activated during seed germination, and what its contrib

  13. The Progress of Solar Cycle 24 at High Latitudes

    OpenAIRE

    Altrock, Richard C.

    2010-01-01

    The "extended" solar cycle 24 began in 1999 near 70 degrees latitude, similarly to cycle 23 in 1989 and cycle 22 in 1979. The extended cycle is manifested by persistent Fe XIV coronal emission appearing near 70 degrees latitude and slowly migrating towards the equator, merging with the latitudes of sunspots and active regions (the "butterfly diagram") after several years. Cycle 24 began its migration at a rate 40% slower than the previous two solar cycles, thus indicating the possibility of a...

  14. Fuel cell hybrid taxi life cycle analysis

    International Nuclear Information System (INIS)

    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 CO2 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 CO2 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 CO2 emissions results. → A hydrogen powered solution can be a sustainable alternative in a full life cycle framework.

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

    Science.gov (United States)

    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

    2016-08-01

    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 G1/G0 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. PMID:27183329

  16. 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.

  17. 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). PMID:15834800

  18. Cucurbitacin-I inhibits Aurora kinase A, Aurora kinase B and survivin, induces defects in cell cycle progression and promotes ABT-737-induced cell death in a caspase-independent manner in malignant human glioma cells

    OpenAIRE

    Premkumar, Daniel R.; Jane, Esther P.; Pollack, Ian F.

    2014-01-01

    Because STAT signaling is commonly activated in malignant gliomas as a result of constitutive EGFR activation, strategies for inhibiting the EGFR/JAK/STAT cascade are of significant interest. We, therefore, treated a panel of established glioma cell lines, including EGFR overexpressors, and primary cultures derived from patients diagnosed with glioblastoma with the JAK/STAT inhibitor cucurbitacin-I. Treatment with cucurbitacin-I depleted p-STAT3, p-STAT5, p-JAK1 and p-JAK2 levels, inhibited c...

  19. Cell cycle delays in synchronized cell populations following irradiation with heavy ions

    International Nuclear Information System (INIS)

    Mammalian cells subjected to irradiation with heavy ions were investigated for cell cycle delays. The ions used for this purpose included Ne ions in the LET range of 400 keV/μm just as well as uranium ions of 16225 keV/μm. The qualitative changes in cell cycle progression seen after irradiation with Ne ions (400 keV/μm) were similar to those observed in connection with X-rays. Following irradiation with extremely heavy ions (lead, uranium) the majority of cells were even at 45 hours still found to be in the S phase or G2M phase of the first cycle. The delay cross section 'σ-delay' was introduced as a quantity that would permit quantitative comparisons to be carried out between the changes in cell progression and other effects of radiation. In order to evaluate the influence of the number of hits on the radiation effect observed, the size of the cell nucleus was precisely determined with reference to the cycle phase and local cell density. A model to simulate those delay effects was designed in such a way that account is taken of this probability of hit and that the results can be extrapolated from the delay effects after X-irradiation. On the basis of the various probabilities of hit for cells at different cycle stages a model was developed to ascertain the intensified effect following fractionated irradiation with heavy ions. (orig./MG)

  20. Viral infections and cell cycle G2/M regulation

    Institute of Scientific and Technical Information of China (English)

    Richard Y.ZHAO; Robert T.ELDER

    2005-01-01

    Progression of cells from G2 phase of the cell cycle to mitosis is a tightly regulated cellular process that requires activation of the Cdc2 kinase, which determines onset of mitosis in all eukaryotic cells. In both human and fission yeast(Schizosaccharomyces pombe) cells, the activity of Cdc2 is regulated in part by the phosphorylation status of tyrosine 15(Tyr15) on Cdc2, which is phosphorylated by Wee1 kinase during late G2 and is rapidly dephosphorylated by the Cdc25 tyrosine phosphatase to trigger entry into mitosis. These Cdc2 regulators are the downstream targets of two well-characterized G2/M checkpoint pathways which prevent cells from entering mitosis when cellular DNA is damaged or when DNA replication is inhibited. Increasing evidence suggests that Cdc2 is also commonly targeted by viral proteins,which modulate host cell cycle machinery to benefit viral survival or replication. In this review, we describe the effect of viral protein R (Vpr) encoded by human immunodeficiency virus type 1 (HIV-1) on cell cycle G2/M regulation. Based on our current knowledge about this viral effect, we hypothesize that Vpr induces cell cycle G2 arrest through a mechanism that is to some extent different from the classic G2/M checkpoints. One the unique features distinguishing Vpr-induced G2 arrest from the classic checkpoints is the role of phosphatase 2A (PP2A) in Vpr-induced G2 arrest.Interestingly, PP2A is targeted by a number of other viral proteins including SV40 small T antigen, polyomavirus T antigen, HTLV Tax and adenovirus E4orf4. Thus an in-depth understanding of the molecular mechanisms underlying Vpr-induced G2 arrest will provide additional insights into the basic biology of cell cycle G2/M regulation and into the biological significance of this effect during host-pathogen interactions.

  1. Loss of CABLES1, a cyclin-dependent kinase-interacting protein that inhibits cell cycle progression, results in germline expansion at the expense of oocyte quality in adult female mice.

    Science.gov (United States)

    Lee, Ho-Joon; Sakamoto, Hideo; Luo, Hongwei; Skaznik-Wikiel, Malgorzata E; Friel, Anne M; Niikura, Teruko; Tilly, Jacqueline C; Niikura, Yuichi; Klein, Rachael; Styer, Aaron K; Zukerberg, Lawrence R; Tilly, Jonathan L; Rueda, Bo R

    2007-11-01

    Recent studies have shown that cell cycle inhibitors encoded by the Ink4a gene locus constrain the self-renewing activity of adult stem cells of the hematopoietic and nervous systems. Here we report that knockout (KO) of the Cables1 [cyclin-dependent kinase (CDK)-5 and ABL enzyme substrate 1] cell cycle-regulatory gene in mice has minimal to no effect on hematopoietic stem cell (HSC) dynamics. However, female Cables1-null mice exhibit a significant expansion of germ cell (oocyte) numbers throughout adulthood. This is accompanied by a dramatic elevation in the number of atretic immature oocytes within the ovaries and an increase in the incidence of degenerating oocytes retrieved following superovulation of CABLES1-deficient females. These outcomes are not observed in mice lacking p16INK4a alone or both p16INK4a and p19ARF. These data support recent reports that adult female mice can generate new oocytes and follicles but the enhancement of postnatal oogenesis by Cables1 KO appears offset by a reduction in oocyte quality, as reflected by increased elimination of these additional germ cells via apoptosis. This work also reveals cell lineage specificity with respect to the role that specific CDK-interacting proteins play in restraining the activity of adult germline versus somatic stem cells. PMID:17912041

  2. Complex Biological Systems Analysis of Cell Cycling Models in Carcinogenesis: I. The essential roles of modifications in the c-Myc, TP53/p53, p27 and hTERT modules in Cancer Initiation and Progression

    CERN Document Server

    Prisecaru, V I

    2004-01-01

    A new approach to the integration of results from a modular, complex biological systems analysis of nonlinear dynamics in cell cycling network transformations that are leading to carcinogenesis is proposed. Carcinogenesis is a complex process that involves dynamically inter-connected biomolecules in the intercellular, membrane, cytosolic, nuclear and nucleolar compartments that form numerous inter-related pathways referred to as networks. One such network module contains the cell cyclins whose functions are essential to cell cycling and division. Cyclins are proteins that also link to several critical pro-apoptotic and other cell cycling/division components, such as: c-Myc, p27, the tumor suppressor gene TP53 and its product-- the p53 protein with key roles in controlling DNA repair, inducing apoptosis and activating p21 (which can depress cell cyclins if activated), mdm2(with its biosynthesis activated by p53 and also, in its turn, inhibiting p53), p21, the Thomsen-Friedenreich antigen(T- antigen),Rb,Bax, Ba...

  3. Effect of Docosahexaenoic Acid on Cell Cycle Pathways in Breast Cell Lines With Different Transformation Degree.

    Science.gov (United States)

    Rescigno, Tania; Capasso, Anna; Tecce, Mario Felice

    2016-06-01

    n-3 polyunsaturated fatty acids (PUFAs), such as eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), abundant in fish, have been shown to affect development and progression of some types of cancer, including breast cancer. The aim of our study was to further analyze and clarify the effects of these nutrients on the molecular mechanisms underlying breast cancer. Following treatments with DHA we examined cell viability, death, cell cycle, and some molecular effects in breast cell lines with different transformation, phenotypic, and biochemical characteristics (MCF-10A, MCF-7, SK-BR-3, ZR-75-1). These investigations showed that DHA is able to affect cell viability, proliferation, and cell cycle progression in a different way in each assayed breast cell line. The activation of ERK1/2 and STAT3 pathways and the expression and/or activation of molecules involved in cell cycle regulation such as p21(Waf1/Cip1) and p53, are very differently regulated by DHA treatments in each cell model. DHA selectively: (i) arrests non tumoral MCF-10A breast cells in G0 /G1 cycle phase, activating p21(Waf1/Cip1) , and p53, (ii) induces to death highly transformed breast cells SK-BR-3, reducing ERK1/2 and STAT3 phosphorylation and (iii) only slightly affects each analyzed process in MCF-7 breast cell line with transformation degree lower than SK-BR-3 cells. These findings suggest a more relevant inhibitory role of DHA within early development and late progression of breast cancer cell transformation and a variable effect in the other phases, depending on individual molecular properties and degree of malignancy of each clinical case. J. Cell. Physiol. 231: 1226-1236, 2016. © 2015 Wiley Periodicals, Inc. PMID:26480024

  4. Ghrelin regulates cell cycle-related gene expression in cultured hippocampal neural stem cells.

    Science.gov (United States)

    Chung, Hyunju; Park, Seungjoon

    2016-08-01

    We have previously demonstrated that ghrelin stimulates the cellular proliferation of cultured adult rat hippocampal neural stem cells (NSCs). However, little is known about the molecular mechanisms by which ghrelin regulates cell cycle progression. The purpose of this study was to investigate the potential effects of ghrelin on cell cycle regulatory molecules in cultured hippocampal NSCs. Ghrelin treatment increased proliferation assessed by CCK-8 proliferation assay. The expression levels of proliferating cell nuclear antigen and cell division control 2, well-known cell-proliferating markers, were also increased by ghrelin. Fluorescence-activated cell sorting analysis revealed that ghrelin promoted progression of cell cycle from G0/G1 to S phase, whereas this progression was attenuated by the pretreatment with specific inhibitors of MEK/extracellular signal-regulated kinase 1/2, phosphoinositide 3-kinase/Akt, mammalian target of rapamycin, and janus kinase 2/signal transducer and activator of transcription 3. Ghrelin-induced proliferative effect was associated with increased expression of E2F1 transcription factor in the nucleus, as determined by Western blotting and immunofluorescence. We also found that ghrelin caused an increase in protein levels of positive regulators of cell cycle, such as cyclin A and cyclin-dependent kinase (CDK) 2. Moreover, p27(KIP1) and p57(KIP2) protein levels were reduced when cell were exposed to ghrelin, suggesting downregulation of CDK inhibitors may contribute to proliferative effect of ghrelin. Our data suggest that ghrelin targets both cell cycle positive and negative regulators to stimulate proliferation of cultured hippocampal NSCs. PMID:27325242

  5. The Progress of Solar Cycle 24 at High Latitudes

    Science.gov (United States)

    Altrock, R. C.

    2010-06-01

    The "extended" solar cycle 24 began in 1999 near 70° latitude, similarly to cycle 23 in 1989 and cycle 22 in 1979. The extended cycle is manifested by persistent Fe XIV coronal emission appearing near 70° latitude and slowly migrating towards the equator, merging with the latitudes of sunspots and active regions (the "butterfly diagram") after several years. Cycle 24 began its migration at a rate 40% slower than the previous two solar cycles, thus indicating the possibility of a peculiar cycle. However, the onset of the "Rush to the Poles" of polar crown prominences and their associated coronal emission, which has been a precursor to solar maximum in recent cycles (cf. Altrock 2003), has just been identified in the northern hemisphere. Peculiarly, this "rush" is leisurely, at only 50% of the rate in the previous two cycles. The properties of the current "Rush to the Poles" yields an estimate of 2013 or 2014 for solar maximum.

  6. The Progress of Solar Cycle 24 at High Latitudes

    CERN Document Server

    Altrock, Richard C

    2010-01-01

    The "extended" solar cycle 24 began in 1999 near 70 degrees latitude, similarly to cycle 23 in 1989 and cycle 22 in 1979. The extended cycle is manifested by persistent Fe XIV coronal emission appearing near 70 degrees latitude and slowly migrating towards the equator, merging with the latitudes of sunspots and active regions (the "butterfly diagram") after several years. Cycle 24 began its migration at a rate 40% slower than the previous two solar cycles, thus indicating the possibility of a peculiar cycle. However, the onset of the "Rush to the Poles" of polar crown prominences and their associated coronal emission, which has been a precursor to solar maximum in recent cycles (cf. Altrock 2003), has just been identified in the northern hemisphere. Peculiarly, this "Rush" is leisurely, at only 50% of the rate in the previous two cycles. The properties of the current "Rush to the Poles" yields an estimate of 2013 or 2014 for solar maximum.

  7. Control points within the cell cycle

    International Nuclear Information System (INIS)

    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

  8. Control points within the cell cycle

    Energy Technology Data Exchange (ETDEWEB)

    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.

  9. Enzymatic fuel cells: Recent progress

    International Nuclear Information System (INIS)

    There is an increasing interest in replacing non-selective metal catalysts, currently used in low temperature fuel cells, with enzymes as catalysts. Specific oxidation of fuel and oxidant by enzymes as catalysts yields enzymatic fuel cells. If the catalysts can be immobilised at otherwise inert anode and cathode materials, this specificity of catalysis obviates the requirement for fuel cell casings and membranes permitting fuel cell configurations amenable to miniaturisation to be adopted. Such configurations have been proposed for application to niche areas of power generation: powering remotely located portable electronic devices, or implanted biomedical devices, for example. We focus in this review on recent efforts to improve electron transfer between the enzymes and electrodes, in the presence or absence of mediators, with most attention on research aimed at implantable or semi-implantable enzymatic fuel cells that harvest the body's own fuel, glucose, coupled to oxygen reduction, to provide power to biomedical devices. This ambitious goal is still at an early stage, with device power output and stability representing major challenges. A comparison of performance of enzymatic fuel cell electrodes and assembled fuel cells is attempted in this review, but is hampered in general by lack of availability of, and conformity to, standardised testing and reporting protocols for electrodes and cells. We therefore highlight reports that focus on this requirement. Ultimately, insight gained from enzymatic fuel cell research will lead to improved biomimetics of enzyme catalysts for fuel cell electrodes. These biomimetics will mimic enzyme catalytic sites and the structural flexibility of the protein assembly surrounding the catalytic site.

  10. Mitochondrial dynamics and the cell cycle

    Science.gov (United States)

    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...

  11. Regulation of the cell cycle via mitochondrial gene expression and energy metabolism in HeLa cells

    Institute of Scientific and Technical Information of China (English)

    Wei Xiong; Yang Jiao; Weiwei Huang; Mingxing Ma; Min Yu; Qinghua Cui; Deyong Tan

    2012-01-01

    Human cervical cancer HeLa cells have functional mitochondria.Recent studies have suggested that mitochondrial metabolism plays an essential role in tumor cell proliferation.Nevertheless,how cells coordinate mitochondrial dynamics and cell cycle progression remains to be clarified.To investigate the relationship between mitochondrial function and cell cycle regulation,the mitochondrial gene expression profile and cellular ATP levels were determined by cell cycle progress analysis in the present study.HeLa cells were synchronized in the G0/G1 phase by serum starvation,and re-entered cell cycle by restoring serum culture,time course experiment was performed to analyze the expression of mitochondrial transcription regulators and mitochondrial genes,mitochondrial membrane potential (MMP),cellular ATP levels,and cell cycle progression.The results showed that when arrested G0/G1 cells were stimulated in serum-containing medium,the amount of DNA and the expression levels of both mRNA and proteins in mitochondria started to increase at 2 h time point,whereas the MMP and ATP level elevated at 4 h.Furthermore,the cyclin D1 expression began to increase at 4 h after serum triggered cell cycle.ATP synthesis inhibitor-oligomycintreatment suppressed the cyclin D1 and cyclin B1 expression levels and blocked cell cycle progression.Taken together,our results suggested that increased mitochondrial gene expression levels,oxidative phosphorylation activation,and cellular ATP content increase are important events for triggering cell cycle.Finally,we demonstrated that mitochondrial gene expression levels and cellular ATP content are tightly regulated and might play a central role in regulating cell proliferation.

  12. Progressive transformation of immortalized esophageal epithelial cells

    Institute of Scientific and Technical Information of China (English)

    Zhong-YingShen; Li-YanXu; Min-HuaChen; JianShen; Wei-JiaCai; YiZeng

    2002-01-01

    AIM:To investigate the progressive transformation of immortal cells of human fetal esophageal epithelium induced by human papillomavirus,and to examine biological criteria of sequential passage of cells,including cellular phenotype,proliferative rate,telomerase,chromosome and tumorigenicity.

  13. Dynamics of the cell-cycle network under genome-rewiring perturbations

    International Nuclear Information System (INIS)

    The cell-cycle progression is regulated by a specific network enabling its ordered dynamics. Recent experiments supported by computational models have shown that a core of genes ensures this robust cycle dynamics. However, much less is known about the direct interaction of the cell-cycle regulators with genes outside of the cell-cycle network, in particular those of the metabolic system. Following our recent experimental work, we present here a model focusing on the dynamics of the cell-cycle core network under rewiring perturbations. Rewiring is achieved by placing an essential metabolic gene exclusively under the regulation of a cell-cycle's promoter, forcing the cell-cycle network to function under a multitasking challenging condition; operating in parallel the cell-cycle progression and a metabolic essential gene. Our model relies on simple rate equations that capture the dynamics of the relevant protein–DNA and protein–protein interactions, while making a clear distinction between these two different types of processes. In particular, we treat the cell-cycle transcription factors as limited ‘resources’ and focus on the redistribution of resources in the network during its dynamics. This elucidates the sensitivity of its various nodes to rewiring interactions. The basic model produces the correct cycle dynamics for a wide range of parameters. The simplicity of the model enables us to study the interface between the cell-cycle regulation and other cellular processes. Rewiring a promoter of the network to regulate a foreign gene, forces a multitasking regulatory load. The higher the load on the promoter, the longer is the cell-cycle period. Moreover, in agreement with our experimental results, the model shows that different nodes of the network exhibit variable susceptibilities to the rewiring perturbations. Our model suggests that the topology of the cell-cycle core network ensures its plasticity and flexible interface with other cellular processes

  14. Comparing American and Chinese Students' Learning Progression on Carbon Cycling in Socio-Ecological Systems

    Science.gov (United States)

    Chen, J.; Anderson, C. W.

    2015-01-01

    Previous studies identified a learning progression on the concept of carbon cycling that was typically followed by American students when they progress from elementary to high school. This study examines the validity of this previously identified learning progression for a different group of learners--Chinese students. The results indicate that…

  15. FUEL CELL/MICRO-TURBINE COMBINED CYCLE

    Energy Technology Data Exchange (ETDEWEB)

    Larry J. Chaney; Mike R. Tharp; Tom W. Wolf; Tim A. Fuller; Joe J. Hartvigson

    1999-12-01

    A wide variety of conceptual design studies have been conducted that describe ultra-high efficiency fossil power plant cycles. The most promising of these ultra-high efficiency cycles incorporate high temperature fuel cells with a gas turbine. Combining fuel cells with a gas turbine increases overall cycle efficiency while reducing per kilowatt emissions. This study has demonstrated that the unique approach taken to combining a fuel cell and gas turbine has both technical and economic merit. The approach used in this study eliminates most of the gas turbine integration problems associated with hybrid fuel cell turbine systems. By using a micro-turbine, and a non-pressurized fuel cell the total system size (kW) and complexity has been reduced substantially from those presented in other studies, while maintaining over 70% efficiency. The reduced system size can be particularly attractive in the deregulated electrical generation/distribution environment where the market may not demand multi-megawatt central stations systems. The small size also opens up the niche markets to this high efficiency, low emission electrical generation option.

  16. Intermittent Stem Cell Cycling Balances Self-Renewal and Senescence of the C. elegans Germ Line

    OpenAIRE

    Cinquin, A.; Chiang, M.; Paz, A.; Hallman, S; Yuan, O; Vysniauskaite, I; Fowlkes, CC; Cinquin, O.

    2016-01-01

    Self-renewing organs often experience a decline in function in the course of aging. It is unclear whether chronological age or external factors control this decline, or whether it is driven by stem cell self-renewal-for example, because cycling cells exhaust their replicative capacity and become senescent. Here we assay the relationship between stem cell cycling and senescence in the Caenorhabditis elegans reproductive system, defining this senescence as the progressive decline in "reproducti...

  17. A stochastic spatiotemporal model of a response-regulator network in the Caulobacter crescentus cell cycle

    Science.gov (United States)

    Li, Fei; Subramanian, Kartik; Chen, Minghan; Tyson, John J.; Cao, Yang

    2016-06-01

    The asymmetric cell division cycle in Caulobacter crescentus is controlled by an elaborate molecular mechanism governing the production, activation and spatial localization of a host of interacting proteins. In previous work, we proposed a deterministic mathematical model for the spatiotemporal dynamics of six major regulatory proteins. In this paper, we study a stochastic version of the model, which takes into account molecular fluctuations of these regulatory proteins in space and time during early stages of the cell cycle of wild-type Caulobacter cells. We test the stochastic model with regard to experimental observations of increased variability of cycle time in cells depleted of the divJ gene product. The deterministic model predicts that overexpression of the divK gene blocks cell cycle progression in the stalked stage; however, stochastic simulations suggest that a small fraction of the mutants cells do complete the cell cycle normally.

  18. Anti-cancer activity of Tonglian decoction against esophageal cancer cell proliferation through regulation of the cell cycle and PI3K/Akt signaling pathway

    Directory of Open Access Journals (Sweden)

    Yongsen Jia

    2015-04-01

    Conclusion: TD could inhibit EC9706 carcinoma cell proliferation by blocking the cell cycle progression in S phase. The possible mechanism was inhibition of multiple targets in the PI3K/Akt signaling pathway by TD.

  19. Altered insulin receptor signalling and β-cell cycle dynamics in type 2 diabetes mellitus.

    Directory of Open Access Journals (Sweden)

    Franco Folli

    Full Text Available Insulin resistance, reduced β-cell mass, and hyperglucagonemia are consistent features in type 2 diabetes mellitus (T2DM. We used pancreas and islets from humans with T2DM to examine the regulation of insulin signaling and cell-cycle control of islet cells. We observed reduced β-cell mass and increased α-cell mass in the Type 2 diabetic pancreas. Confocal microscopy, real-time PCR and western blotting analyses revealed increased expression of PCNA and down-regulation of p27-Kip1 and altered expression of insulin receptors, insulin receptor substrate-2 and phosphorylated BAD. To investigate the mechanisms underlying these findings, we examined a mouse model of insulin resistance in β-cells--which also exhibits reduced β-cell mass, the β-cell-specific insulin receptor knockout (βIRKO. Freshly isolated islets and β-cell lines derived from βIRKO mice exhibited poor cell-cycle progression, nuclear restriction of FoxO1 and reduced expression of cell-cycle proteins favoring growth arrest. Re-expression of insulin receptors in βIRKO β-cells reversed the defects and promoted cell cycle progression and proliferation implying a role for insulin-signaling in β-cell growth. These data provide evidence that human β- and α-cells can enter the cell-cycle, but proliferation of β-cells in T2DM fails due to G1-to-S phase arrest secondary to defective insulin signaling. Activation of insulin signaling, FoxO1 and proteins in β-cell-cycle progression are attractive therapeutic targets to enhance β-cell regeneration in the treatment of T2DM.

  20. The p75NTR tumor suppressor induces cell cycle arrest facilitating caspase mediated apoptosis in prostate tumor cells

    International Nuclear Information System (INIS)

    The p75 neurotrophin receptor (p75NTR) is a death receptor which belongs to the tumor necrosis factor receptor super-family of membrane proteins. This study shows that p75NTR retarded cell cycle progression by induced accumulation of cells in G0/G1 and a reduction in the S phase of the cell cycle. The rescue of tumor cells from cell cycle progression by a death domain deleted (ΔDD) dominant-negative antagonist of p75NTR showed that the death domain transduced anti-proliferative activity in a ligand-independent manner. Conversely, addition of NGF ligand rescued retardation of cell cycle progression with commensurate changes in components of the cyclin/cdk holoenzyme complex. In the absence of ligand, p75NTR-dependent cell cycle arrest facilitated an increase in apoptotic nuclear fragmentation of the prostate cancer cells. Apoptosis of p75NTR expressing cells occurred via the intrinsic mitochondrial pathway leading to a sequential caspase-9 and -7 cascade. Since the death domain deleted dominant-negative antagonist of p75NTR rescued intrinsic caspase associated apoptosis in PC-3 cells, this shows p75NTR was integral to ligand independent induction of apoptosis. Moreover, the ability of ligand to ameliorate the p75NTR-dependent intrinsic apoptotic cascade indicates that NGF functioned as a survival factor for p75NTR expressing prostate cancer cells

  1. The progression of the intra-erythrocytic cell cycle of Plasmodium falciparum and the role of the centriolar plaques in asynchronous mitotic division during schizogony

    DEFF Research Database (Denmark)

    Arnot, David E; Ronander, Elena; Bengtsson, Dominique C

    2011-01-01

    The cell division cycle and mitosis of intra-erythrocytic (IE) Plasmodium falciparum are poorly understood aspects of parasite development which affect malaria molecular pathogenesis. Specifically, the timing of the multiple gap (G), DNA synthesis (S) and chromosome separation (M) phases of...... parasite mitosis are not well defined, nor whether genome divisions are immediately followed by cleavage of the nuclear envelope. Curiously, daughter merozoite numbers do not follow the geometric expansion expected from equal numbers of binary divisions, an outcome difficult to explain using the standard...

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

    OpenAIRE

    El-Badawy, Ahmed; El-Badri, Nagwa

    2016-01-01

    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 ...

  3. Research Establishment progress report 1978 - uranium fuel cycle

    International Nuclear Information System (INIS)

    A report of research programs continuing in the following areas is presented: mining and treatment of uranium ores, uranium enrichment, waste treatment, reprocessing and the uranium fuel cycle. Staff responsible for each project are indicated

  4. Ras signalling linked to the cell-cycle machinery by the retinoblastoma protein

    OpenAIRE

    Peeper, D.S.; Upton, T.M.; Ladha, M H; Neuman, E; Zalvide, J; Bernards, R.A.; DeCaprio, J A; Ewen, M E

    1997-01-01

    The Ras proto-oncogene is a central component of mitogenic signal-transduction pathways, and is essential for cells both to leave a quiescent state (GO) and to pass through the GI/S transition of the cell cycle. The mechanism by which Ras signalling regulates cell-cycle progression is unclear, however. Here we report that the retinoblastoma tumour-suppressor protein (Rb), a regulator of GI exit, functionally links Ras to passage through the Gl phase. Inactivation of Ras in cycling cells cause...

  5. Changes of the cell cycle regulators and cell cycle arrest in cervical cancer cells after cisplatin therapy

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    Objective To investigate the changes of the cell cycle regulators ATM,Chk2 and p53 and cell cycle arrest in HeLa cells after cisplatin therapy. Methods The proliferation-inhibiting rates of HeLa cells induced by cisplatin of different concentrations were measured by MTT assays. The mRNA and protein expressions of ATM,Chk2 and p53 of HeLa cells with and without cisplatin were detected by RT-PCR and Western blot,respectively. The cell cycle analysis was conducted by flow cytometric analysis. Results Cisplatin...

  6. Tumor-suppressor genes, cell cycle regulatory checkpoints, and the skin

    Directory of Open Access Journals (Sweden)

    Ana Maria Abreu Velez

    2015-01-01

    Full Text Available The cell cycle (or cell-division cycle is a series of events that take place in a cell, leading to its division and duplication. Cell division requires cell cycle checkpoints (CPs that are used by the cell to both monitor and regulate the progress of the cell cycle. Tumor-suppressor genes (TSGs or antioncogenes are genes that protect the cell from a single event or multiple events leading to cancer. When these genes mutate, the cell can progress to a cancerous state. We aimed to perform a narrative review, based on evaluation of the manuscripts published in MEDLINE-indexed journals using the Medical Subject Headings (MeSH terms "tumor suppressor′s genes," "skin," and "cell cycle regulatory checkpoints." We aimed to review the current concepts regarding TSGs, CPs, and their association with selected cutaneous diseases. It is important to take into account that in some cell cycle disorders, multiple genetic abnormalities may occur simultaneously. These abnormalities may include intrachromosomal insertions, unbalanced division products, recombinations, reciprocal deletions, and/or duplication of the inserted segments or genes; thus, these presentations usually involve several genes. Due to their complexity, these disorders require specialized expertise for proper diagnosis, counseling, personal and family support, and genetic studies. Alterations in the TSGs or CP regulators may occur in many benign skin proliferative disorders, neoplastic processes, and genodermatoses.

  7. Propionibacterium acnes inhibits FOXM1 and induces cell cycle alterations in human primary prostate cells

    DEFF Research Database (Denmark)

    Sayanjali, Behnam; Christensen, Gitte J M; Al-Zeer, Munir A;

    2016-01-01

    Propionibacterium acnes has been detected in diseased human prostate tissue, and cell culture experiments suggest that the bacterium can establish a low-grade inflammation. Here, we investigated its impact on human primary prostate epithelial cells. Microarray analysis confirmed the inflammation......-inducing capability of P. acnes but also showed deregulation of genes involved in the cell cycle. qPCR experiments showed that viable P. acnes downregulates a master regulator of cell cycle progression, FOXM1. Flow cytometry experiments revealed that P. acnes increases the number of cells in S-phase. We tested the...... hypothesis that a P. acnes-produced berninamycin-like thiopeptide is responsible for this effect, since it is related to the FOXM1 inhibitor siomycin. The thiopeptide biosynthesis gene cluster was strongly expressed; it is present in subtype IB of P. acnes, but absent from type IA, which is most abundant on...

  8. A cell cycle timer for asymmetric spindle positioning.

    Directory of Open Access Journals (Sweden)

    Erin K McCarthy Campbell

    2009-04-01

    Full Text Available The displacement of the mitotic spindle to one side of a cell is important for many cells to divide unequally. While recent progress has begun to unveil some of the molecular mechanisms of mitotic spindle displacement, far less is known about how spindle displacement is precisely timed. A conserved mitotic progression mechanism is known to time events in dividing cells, although this has never been linked to spindle displacement. This mechanism involves the anaphase-promoting complex (APC, its activator Cdc20/Fizzy, its degradation target cyclin, and cyclin-dependent kinase (CDK. Here we show that these components comprise a previously unrecognized timer for spindle displacement. In the Caenorhabditis elegans zygote, mitotic spindle displacement begins at a precise time, soon after chromosomes congress to the metaphase plate. We found that reducing the function of the proteasome, the APC, or Cdc20/Fizzy delayed spindle displacement. Conversely, inactivating CDK in prometaphase caused the spindle to displace early. The consequence of experimentally unlinking spindle displacement from this timing mechanism was the premature displacement of incompletely assembled components of the mitotic spindle. We conclude that in this system, asymmetric positioning of the mitotic spindle is normally delayed for a short time until the APC inactivates CDK, and that this delay ensures that the spindle does not begin to move until it is fully assembled. To our knowledge, this is the first demonstration that mitotic progression times spindle displacement in the asymmetric division of an animal cell. We speculate that this link between the cell cycle and asymmetric cell division might be evolutionarily conserved, because the mitotic spindle is displaced at a similar stage of mitosis during asymmetric cell divisions in diverse systems.

  9. Centrioles in the cell cycle. I. Epithelial cells

    OpenAIRE

    1982-01-01

    A study was made of the structure of the centrosome in the cell cycle in a nonsynchronous culture of pig kidney embryo (PE) cells. In the spindle pole of the metaphase cell there are two mutually perpendicular centrioles (mother and daughter) which differ in their ultrastructure. An electron-dense halo, which surrounds only the mother centriole and is the site where spindle microtubules converge, disappears at the end of telophase. In metaphase and anaphase, the mother centriole is situated p...

  10. Acanthamoeba induces cell-cycle arrest in host cells

    OpenAIRE

    Sissons, J.; Alsam, S.; Jayasekera, S.; Kim, K S; Stins, M; Khan, Naveed Ahmed

    2004-01-01

    Acanthamoeba can cause fatal granulomatous amoebic encephalitis (GAE) and eye keratitis. However, the pathogenesis and pathophysiology of these emerging diseases remain unclear. In this study, the effects of Acanthamoeba on the host cell cycle using human brain microvascular endothelial cells (HBMEC) and human corneal epithelial cells (HCEC) were determined. Two isolates of Acanthamoeba belonging to the T1 genotype (GAE isolate) and T4 genotype (keratitis isolate) were used, which showed seve...

  11. Cell cycle and anti-estrogen effects synergize to regulate cell proliferation and ER target gene expression.

    Directory of Open Access Journals (Sweden)

    Mathieu Dalvai

    Full Text Available Antiestrogens are designed to antagonize hormone induced proliferation and ERalpha target gene expression in mammary tumor cells. Commonly used drugs such as OH-Tamoxifen and ICI 182780 (Fulvestrant block cell cycle progression in G0/G1. Inversely, the effect of cell cycle stage on ER regulated gene expression has not been tested directly. We show that in ERalpha-positive breast cancer cells (MCF-7 the estrogen receptor gene and downstream target genes are cell cycle regulated with expression levels varying as much as three-fold between phases of the cell cycle. Steroid free culture conditions commonly used to assess the effect of hormones or antiestrogens on gene expression also block MCF-7 cells in G1-phase when several ERalpha target genes are overexpressed. Thus, cell cycle effects have to be taken into account when analyzing the impact of hormonal treatments on gene transcription. We found that antiestrogens repress transcription of several ERalpha target genes specifically in S phase. This observation corroborates the more rapid and strong impact of antiestrogen treatments on cell proliferation in thymidine, hydroxyurea or aphidicolin arrested cells and correlates with an increase of apoptosis compared to similar treatments in lovastatin or nocodazol treated cells. Hence, cell cycle effects synergize with the action of antiestrogens. An interesting therapeutic perspective could be to enhance the action of anti-estrogens by associating hormone-therapy with specific cell cycle drugs.

  12. Oncogenic transformation through the cell cycle and the LET dependent inverse dose rate effect

    International Nuclear Information System (INIS)

    Synchronised populations of mouse C3H/10T-1/2 cells were obtained by a stringent mitotic dislodgment procedure. Mitotic cells rapidly attach and progress sequentially through the cell cycle. Irradiation (3Gy of X rays) was carried out at intervals from 0 to 18 h after initiating cell cycle progression of the mitotic cells. Oncogenic transformation was enhanced 10-fold over cells irradiated soon after replating (G1 and S phases) for cells in a near 2 h period corresponding to cells in G2 phase but not in mitosis. The cell surviving fraction had a 2-1/2-fold variation with resistant peaks corresponding to the late G1 and late S phases. (Author)

  13. Boron neutron capture therapy induces cell cycle arrest and cell apoptosis of glioma stem/progenitor cells in vitro

    International Nuclear Information System (INIS)

    Glioma stem cells in the quiescent state are resistant to clinical radiation therapy. An almost inevitable glioma recurrence is due to the persistence of these cells. The high linear energy transfer associated with boron neutron capture therapy (BNCT) could kill quiescent and proliferative cells. The present study aimed to evaluate the effects of BNCT on glioma stem/progenitor cells in vitro. The damage induced by BNCT was assessed using cell cycle progression, apoptotic cell ratio and apoptosis-associated proteins expression. The surviving fraction and cell viability of glioma stem/progenitor cells were decreased compared with differentiated glioma cells using the same boronophenylalanine pretreatment and the same dose of neutron flux. BNCT induced cell cycle arrest in the G2/M phase and cell apoptosis via the mitochondrial pathway, with changes in the expression of associated proteins. Glioma stem/progenitor cells, which are resistant to current clinical radiotherapy, could be effectively killed by BNCT in vitro via cell cycle arrest and apoptosis using a prolonged neutron irradiation, although radiosensitivity of glioma stem/progenitor cells was decreased compared with differentiated glioma cells when using the same dose of thermal neutron exposure and boronophenylalanine pretreatment. Thus, BNCT could offer an appreciable therapeutic advantage to prevent tumor recurrence, and may become a promising treatment in recurrent glioma

  14. TRAP1 regulates cell cycle and apoptosis in thyroid carcinoma cells.

    Science.gov (United States)

    Palladino, Giuseppe; Notarangelo, Tiziana; Pannone, Giuseppe; Piscazzi, Annamaria; Lamacchia, Olga; Sisinni, Lorenza; Spagnoletti, Girolamo; Toti, Paolo; Santoro, Angela; Storto, Giovanni; Bufo, Pantaleo; Cignarelli, Mauro; Esposito, Franca; Landriscina, Matteo

    2016-09-01

    Tumor necrosis factor receptor-associated protein 1 (TRAP1) is a heat shock protein 90 (HSP90) molecular chaperone upregulated in several human malignancies and involved in protection from apoptosis and drug resistance, cell cycle progression, cell metabolism and quality control of specific client proteins. TRAP1 role in thyroid carcinoma (TC), still unaddressed at present, was investigated by analyzing its expression in a cohort of 86 human TCs and evaluating its involvement in cancer cell survival and proliferation in vitro Indeed, TRAP1 levels progressively increased from normal peritumoral thyroid gland, to papillary TCs (PTCs), follicular variants of PTCs (FV-PTCs) and poorly differentiated TCs (PDTCs). By contrast, anaplastic thyroid tumors exhibited a dual pattern, the majority being characterized by high TRAP1 levels, while a small subgroup completely negative. Consistently with a potential involvement of TRAP1 in thyroid carcinogenesis, TRAP1 silencing resulted in increased sensitivity to paclitaxel-induced apoptosis, inhibition of cell cycle progression and attenuation of ERK signaling. Noteworthy, the inhibition of TRAP1 ATPase activity by pharmacological agents resulted in attenuation of cell proliferation, inhibition of ERK signaling and reversion of drug resistance. These data suggest that TRAP1 inhibition may be regarded as potential strategy to target specific features of human TCs, i.e., cell proliferation and resistance to apoptosis. PMID:27422900

  15. E2F Transcription Factors Control the Roller Coaster Ride of Cell Cycle Gene Expression.

    Science.gov (United States)

    Thurlings, Ingrid; de Bruin, Alain

    2016-01-01

    Initially, the E2F transcription factor was discovered as a factor able to bind the adenovirus E2 promoter and activate viral genes. Afterwards it was shown that E2F also binds to promoters of nonviral genes such as C-MYC and DHFR, which were already known at that time to be important for cell growth and DNA metabolism, respectively. These findings provided the first clues that the E2F transcription factor might be an important regulator of the cell cycle. Since this initial discovery in 1987, several additional E2F family members have been identified, and more than 100 targets genes have been shown to be directly regulated by E2Fs, the majority of these are important for controlling the cell cycle. The progression of a cell through the cell cycle is accompanied with the increased expression of a specific set of genes during one phase of the cell cycle and the decrease of the same set of genes during a later phase of the cell cycle. This roller coaster ride, or oscillation, of gene expression is essential for the proper progression through the cell cycle to allow accurate DNA replication and cell division. The E2F transcription factors have been shown to be critical for the temporal expression of the oscillating cell cycle genes. This review will focus on how the oscillation of E2Fs and their targets is regulated by transcriptional, post-transcriptional and post-translational mechanism in mammals, yeast, flies, and worms. Furthermore, we will discuss the functional impact of E2Fs on the cell cycle progression and outline the consequences when E2F expression is disturbed. PMID:26254918

  16. Progress in Multi-Disciplinary Data Life Cycle Management

    Science.gov (United States)

    Jung, C.; Gasthuber, M.; Giesler, A.; Hardt, M.; Meyer, J.; Prabhune, A.; Rigoll, F.; Schwarz, K.; Streit, A.

    2015-12-01

    Modern science is most often driven by data. Improvements in state-of-the-art technologies and methods in many scientific disciplines lead not only to increasing data rates, but also to the need to improve or even completely overhaul their data life cycle management. Communities usually face two kinds of challenges: generic ones like federated authorization and authentication infrastructures and data preservation, and ones that are specific to their community and their respective data life cycle. In practice, the specific requirements often hinder the use of generic tools and methods. The German Helmholtz Association project ’’Large-Scale Data Management and Analysis” (LSDMA) addresses both challenges: its five Data Life Cycle Labs (DLCLs) closely collaborate with communities in joint research and development to optimize the communities data life cycle management, while its Data Services Integration Team (DSIT) provides generic data tools and services. We present most recent developments and results from the DLCLs covering communities ranging from heavy ion physics and photon science to high-throughput microscopy, and from DSIT.

  17. Alterations in G1 to S Phase Cell-Cycle Regulators during Amyotrophic Lateral Sclerosis

    OpenAIRE

    Ranganathan, Srikanth; Bowser, Robert

    2003-01-01

    Amyotrophic lateral sclerosis (ALS) is characterized by progressive degeneration of the motor neurons in the cerebral cortex, brain stem, and spinal cord. However, the mechanisms that regulate the initiation and/or progression of motor neuron loss in this disease remain enigmatic. Cell-cycle proteins and transcriptional regulators such as cyclins, cyclin-associated kinases, the retinoblastoma gene product (pRb), and E2F-1 function during cellular proliferation, differentiation, and cell death...

  18. Nuclear fuel cycle under progressing preparation of its systemisation

    International Nuclear Information System (INIS)

    Trends of nuclear development in Japan show more remarkable advancements in 2000, such as new addition of nuclear power plant, nuclear fuel cycling business, and so on. Based on an instruction of the criticality accident in JCO formed on September, 1999, government made efforts on revision of the law on regulation of nuclear reactor and so forth and establishment of a law on protection of nuclear accident as sooner, to enforce nuclear safety management and nuclear accident protective countermeasure. On the other hand, the nuclear industry field develops some new actions such as establishment of Nuclear Safety Network (NSnet)', mutual evaluation of nuclear-relative works (pier review), and so forth. And, on the high level radioactive wastes disposal of the most important subject remained in nuclear development, the Nuclear Waste Management Organization of Japan' of its main business body was established on October, 1999 together with establishment of the new law, to begin a business for embodiment of the last disposal aiming at 2030s to 2040s. On the same October, the Japan Nuclear Fuel Limited. concluded a safety agreement on premise of full-dress transportation of the used fuels to the Rokkasho Reprocessing Plant in Aomori prefecture with local government, to begin their transportation from every electric company since its year end. Here were described on development of the nuclear fuel cycling business in Japan, establishment of nuclear fuel cycling, disposal on the high level radioactive wastes, R and D on geological disposal of the high level radioactive wastes, establishment on cycle back-end of nuclear fuels, and full-dressing of nuclear fuel cycling. (G.K.)

  19. Progress and status of the Integral Fast Reactor (IFR) fuel cycle development

    International Nuclear Information System (INIS)

    The Integral Fast Reactor (IFR) fuel cycle holds promise for substantial improvements in economics, diversion-resistance, and waste management. This paper discusses technical features of the IFR fuel cycle, its technical progress, the development status, and the future plans and directions. 10 refs

  20. Progress and status of the Integral Fast Reactor (IFR) fuel cycle development

    International Nuclear Information System (INIS)

    The Integral Fast Reactor (IFR) fuel cycle holds promise for substantial improvements in economics, diversion-resistance, and waste management. This paper discusses technical features of the IFR fuel cycle, its technical progress, the development status, and the future plans and directions

  1. 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. PMID:26132923

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

    Directory of Open Access Journals (Sweden)

    Tormi Reinson

    Full Text Available 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.

  3. The effects of phenoxodiol on the cell cycle of prostate cancer cell lines

    OpenAIRE

    Mahoney, Simon; Arfuso, Frank; Millward, Michael; Dharmarajan, Arun

    2014-01-01

    Background Prostate cancer is associated with a poor survival rate. The ability of cancer cells to evade apoptosis and exhibit limitless replication potential allows for progression of cancer from a benign to a metastatic phenotype. The aim of this study was to investigate in vitro the effect of the isoflavone phenoxodiol on the expression of cell cycle genes. Methods Three prostate cancer cell lines-LNCaP, DU145, and PC3 were cultured in vitro, and then treated with phenoxodiol (10 μM and 30...

  4. DNA Damage, Cell Cycle Arrest, and Apoptosis Induction Caused by Lead in Human Leukemia Cells

    OpenAIRE

    Yedjou, Clement G.; Tchounwou, Hervey M.; Tchounwou, Paul B.

    2015-01-01

    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(NO3)2] 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(NO3)...

  5. Antiproliferative effect of rapamycin on human T-cell leukemia cell line Jurkat by cell cycle arrest and telomerase inhibition

    Institute of Scientific and Technical Information of China (English)

    Yan-min ZHAO; Qian ZHOU; Yun XU; Xiao-yu LAI; He HUANG

    2008-01-01

    Aim:To examine the ability of rapamycin to suppress growth and regulate telomerase activity in the human T-cell leukemia cell line Jurkat. Methods:Cell proliferation was assessed after exposure to rapamycin by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. Cell cycle progression and apoptosis were determined by flow cytometry. The proteins important for cell cycle progres-sion and Akt/mammalian target of rapamycin signaling cascade were assessed by Western blotting. Telomerase activity was quantified by telomeric repeat amplication protocol assay. The human telomerase reverse transcriptase (hTERT) mRNA levels were determined by semi-quantitative RT-PCR. Results:Rapamycin inhibited the proliferation of Jurkat, induced G1 phase arrest, unregulated the pro-tein level of p21 as well as p27, and downregulated cyclinD3, phospho-p70s6k, and phospho-s6, but had no effect on apoptosis. Treatment with rapamycin reduced telomerase activity, and reduced hTERT mRNA and protein expression. Conclusion:Rapamycin displayed a potent antileukemic effect in the human T-cell leukemia cell line by inhibition of cell proliferation through G1 cell cycle arrest and also through the suppression of telomerase activity, suggesting that rapamycin may have potential clinical implications in the treatment of some leukemias.

  6. Technical Progress in Transport and the Tourism Area Life Cycle

    OpenAIRE

    Andrew Kato; James Mak

    2010-01-01

    Richard ButlerÕs tourism area life cycle envisions tourism destinations to evolve in stages from exploration to rapid growth followed by slackening, stagnation, and even decline. The eventual slow-down in tourism growth is attributed to the destinations reaching their physical and social carrying capacities. This article examines the evolution of Hawaii as a tourism destination from 1922 to 2009. We demonstrate that tourism growth in Hawaii has declined but not because the destination has rea...

  7. DNA Damage, Cell Cycle Arrest, and Apoptosis Induction Caused by Lead in Human Leukemia Cells.

    Science.gov (United States)

    Yedjou, Clement G; Tchounwou, Hervey M; Tchounwou, Paul B

    2016-01-01

    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(NO₃)₂] 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(NO₃)₂ 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 rupture by Pb(NO₃)₂ 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(NO₃)₂ 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(NO₃)₂ 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(NO₃)₂ 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(NO₃)₂ exposure and its associated adverse health effects. PMID:26703663

  8. Progress and prospects in stem cell therapy

    Institute of Scientific and Technical Information of China (English)

    Xiu-ling XU; Fei YI; Hui-ze PAN; Shun-lei DUAN; Zhi-chao DING; Guo-hong YUAN; Jing QU

    2013-01-01

    In the past few years,progress being made in stem cell studies has incontestably led to the hope of developing cell replacement based therapy for diseases deficient in effective treatment by conventional ways.The induced pluripotent stem cells (iPSCs) are of great interest of cell therapy research because of their unrestricted self-renewal and differentiation potentials.Proof of principle studies have successfully demonstrated that iPSCs technology would substantially benefit clinical studies in various areas,including neurological disorders,hematologic diseases,cardiac diseases,liver diseases and etc.On top of this,latest advances of gene editing technologies have vigorously endorsed the possibility of obtaining disease-free autologous cells from patient specific iPSCs.Here in this review,we summarize current progress of stem cell therapy research with special enthusiasm in iPSCs studies.In addition,we compare current gene editing technologies and discuss their potential implications in clinic application in the future.

  9. Nuclear Reorganization of Mammalian DNA Synthesis Prior to Cell Cycle Exit

    OpenAIRE

    Barbie, David A; Kudlow, Brian A.; Frock, Richard; Zhao, Jiyong; Johnson, Brett R.; Dyson, Nicholas; Harlow, Ed; Kennedy, Brian K.

    2004-01-01

    In primary mammalian cells, DNA replication initiates in a small number of perinucleolar, lamin A/C-associated foci. During S-phase progression in proliferating cells, replication foci distribute to hundreds of sites throughout the nucleus. In contrast, we find that the limited perinucleolar replication sites persist throughout S phase as cells prepare to exit the cell cycle in response to contact inhibition, serum starvation, or replicative senescence. Proteins known to be involved in DNA sy...

  10. Progress in Microbial Fuel Cells Energy Production

    International Nuclear Information System (INIS)

    Microbial fuel cells (MFCs) harness the natural metabolisms of microbes to produce electrical power from almost any kind of organic matter. In addition to the low power densities (about 1mW for a 1-liter reactor), MFCs are presently built with expensive membrane and electrodes. The payback time of MFCs is therefore very long (evaluated to 25000 years for our lab prototype). Progresses in designing low-cost MFCs are necessary before conceiving large scale energy production. (author)

  11. 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.

  12. TGEV nucleocapsid protein induces cell cycle arrest and apoptosis through activation of p53 signaling

    Energy Technology Data Exchange (ETDEWEB)

    Ding, Li [College of Veterinary Medicine, Northwest A and F University, Yangling, Shaanxi 712100 (China); College of Life Sciences, Hainan Normal University, Haikou, Hainan 571158 (China); Huang, Yong; Du, Qian; Dong, Feng; Zhao, Xiaomin; Zhang, Wenlong; Xu, Xingang [College of Veterinary Medicine, Northwest A and F University, Yangling, Shaanxi 712100 (China); Tong, Dewen, E-mail: dwtong@nwsuaf.edu.cn [College of Veterinary Medicine, Northwest A and F University, Yangling, Shaanxi 712100 (China)

    2014-03-07

    Highlights: • TGEV N protein reduces cell viability by inducing cell cycle arrest and apoptosis. • TGEV N protein induces cell cycle arrest and apoptosis by regulating p53 signaling. • TGEV N protein plays important roles in TGEV-induced cell cycle arrest and apoptosis. - Abstract: Our previous studies showed that TGEV infection could induce cell cycle arrest and apoptosis via activation of p53 signaling in cultured host cells. However, it is unclear which viral gene causes these effects. In this study, we investigated the effects of TGEV nucleocapsid (N) protein on PK-15 cells. We found that TGEV N protein suppressed cell proliferation by causing cell cycle arrest at the S and G2/M phases and apoptosis. Characterization of various cellular proteins that are involved in regulating cell cycle progression demonstrated that the expression of N gene resulted in an accumulation of p53 and p21, which suppressed cyclin B1, cdc2 and cdk2 expression. Moreover, the expression of TGEV N gene promoted translocation of Bax to mitochondria, which in turn caused the release of cytochrome c, followed by activation of caspase-3, resulting in cell apoptosis in the transfected PK-15 cells following cell cycle arrest. Further studies showed that p53 inhibitor attenuated TGEV N protein induced cell cycle arrest at S and G2/M phases and apoptosis through reversing the expression changes of cdc2, cdk2 and cyclin B1 and the translocation changes of Bax and cytochrome c induced by TGEV N protein. Taken together, these results demonstrated that TGEV N protein might play an important role in TGEV infection-induced p53 activation and cell cycle arrest at the S and G2/M phases and apoptosis occurrence.

  13. 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

  14. The one-cell mouse embryo: cell cycle-dependent radiosensitivity and development of chromosomal anomalies in postradiation cell cycles

    International Nuclear Information System (INIS)

    One-cell mouse embryos were irradiated with X-rays at different cell cycle stages. Examination of structural chromosomal anomalies and micronucleus formation in postradiation mitoses and interphases demonstrated cell cycle-dependent radiosensitivities in the order: late G2 phase > G1 phase > S phase > early G2 phase > stage of decondensing nuclei. Comparison of the quality and quantity of chromosomal aberrations from the first to third mitosis led to the conclusion that new chromosomal anomalies were formed in the course of postirradiation cell cycles. This hypothesis was supported by an increasing number of micronuclei from 24 to 48 h post-conception. In addition to structural chromosomal aberrations, radiation-induced chromosome loss was observed with a frequency that was obviously independent of the exposed cell cycle phase. Loss of acentric chromosome fragments and of single chromosomes contributed to the micronucleus formation. (author)

  15. Transcriptome changes and cAMP oscillations in an archaeal cell cycle

    Directory of Open Access Journals (Sweden)

    Soppa Jörg

    2007-06-01

    Full Text Available Abstract Background The cell cycle of all organisms includes mass increase by a factor of two, replication of the genetic material, segregation of the genome to different parts of the cell, and cell division into two daughter cells. It is tightly regulated and typically includes cell cycle-specific oscillations of the levels of transcripts, proteins, protein modifications, and signaling molecules. Until now cell cycle-specific transcriptome changes have been described for four eukaryotic species ranging from yeast to human, but only for two prokaryotic species. Similarly, oscillations of small signaling molecules have been identified in very few eukaryotic species, but not in any prokaryote. Results A synchronization procedure for the archaeon Halobacterium salinarum was optimized, so that nearly 100% of all cells divide in a time interval that is 1/4th of the generation time of exponentially growing cells. The method was used to characterize cell cycle-dependent transcriptome changes using a genome-wide DNA microarray. The transcript levels of 87 genes were found to be cell cycle-regulated, corresponding to 3% of all genes. They could be clustered into seven groups with different transcript level profiles. Cluster-specific sequence motifs were detected around the start of the genes that are predicted to be involved in cell cycle-specific transcriptional regulation. Notably, many cell cycle genes that have oscillating transcript levels in eukaryotes are not regulated on the transcriptional level in H. salinarum. Synchronized cultures were also used to identify putative small signaling molecules. H. salinarum was found to contain a basal cAMP concentration of 200 μM, considerably higher than that of yeast. The cAMP concentration is shortly induced directly prior to and after cell division, and thus cAMP probably is an important signal for cell cycle progression. Conclusion The analysis of cell cycle-specific transcriptome changes of H. salinarum

  16. Progress in Electrolyte-Free Fuel Cells

    Directory of Open Access Journals (Sweden)

    Yuzheng eLu

    2016-05-01

    Full Text Available Solid Oxide Fuel Cell (SOFC represents a clean electrochemical energy conversion technology with characteristics of high conversion efficiency and low emissions. It is one of the most important new energy technologies in the future. However, the manufacture of SOFCs based on the structure of anode/electrolyte/cathode is complicated and time-consuming. Thus, the cost for the entire fabrication and technology is too high to be affordable and challenges still hinder commercialization. Recently, a novel type of Electrolyte -free fuel cell (EFFC with single component was invented which could be the potential candidate for the next generation of advanced fuel cells. This paper briefly introduces the EFFC, working principle, performance and advantages with updated research progress. A number of key R&D issues about EFFCs have been addressed and future opportunities and challenges are discussed.

  17. Recent progress in crystalline silicon solar cells

    International Nuclear Information System (INIS)

    In 1954, a solar cell was proposed for the first time that uses a Si pn-junction. The first and today still important application was as power generator for satellites in space. For this purpose, reliable, high performance, specially adapted and therefore expensive single crystal Si solar cells were developed. Since the beginning of the last decade, photovoltaics have been widely studied and developed as a new energy source for terrestrial use. So, research has been carried out from the point of view of materials, fabrication processes, structures and systems. First efforts aimed mainly at strong cost reductions. The results are the development of new low-cost and high-throughput cell fabrication technologies as screen-printing and the use of polycrystalline silicon as base material. However, progress in development of a new ''solar-grade'' silicon sheet material was slower and potential for cost reduction in module/system fabrication was smaller as expected originally. Consequently, since most silicon and module material costs are area-related, various tries to improve the efficiency have been undertaken. In this report, recent progress in the above mentioned topics will be reviewed. Besides this, some aspects of the module fabrication and performance will be discussed and some interesting applications presented. 89 refs, 33 figs, 2 tabs

  18. Cell-cycle-independent transitions in temporal identity of mammalian neural progenitor cells

    Science.gov (United States)

    Okamoto, Mayumi; Miyata, Takaki; Konno, Daijiro; Ueda, Hiroki R.; Kasukawa, Takeya; Hashimoto, Mitsuhiro; Matsuzaki, Fumio; Kawaguchi, Ayano

    2016-01-01

    During cerebral development, many types of neurons are sequentially generated by self-renewing progenitor cells called apical progenitors (APs). Temporal changes in AP identity are thought to be responsible for neuronal diversity; however, the mechanisms underlying such changes remain largely unknown. Here we perform single-cell transcriptome analysis of individual progenitors at different developmental stages, and identify a subset of genes whose expression changes over time but is independent of differentiation status. Surprisingly, the pattern of changes in the expression of such temporal-axis genes in APs is unaffected by cell-cycle arrest. Consistent with this, transient cell-cycle arrest of APs in vivo does not prevent descendant neurons from acquiring their correct laminar fates. Analysis of cultured APs reveals that transitions in AP gene expression are driven by both cell-intrinsic and -extrinsic mechanisms. These results suggest that the timing mechanisms controlling AP temporal identity function independently of cell-cycle progression and Notch activation mode. PMID:27094546

  19. Effect of genistein on cell cycle of bone marrow hematopoietic cells in normal and irradiated mice

    International Nuclear Information System (INIS)

    Objective: To study the effects of genistein on cell cycle, proliferation and expression of bcl-2 gene in bone marrow hematopoietic cells (BMHCs) of normal and irradiated mice in order to explore mechanisms for protection of genistein from radiation-induced hematopoietic system injury. Methods: Adult male BALB/c mice were orally administered with genistein (160 mg/kg b.w.) 24 h before irradiation. Cell cycles in BMHCs of the normal and irradiated mice were measured by flow cytometry. The protein and mRNA expressions of bcl-2 gene in BMHCs were analyzed by Western blot and RT-PCR, respectively. Results: a) Transitory and significant changes occurred in the cell cycle of BMHCs in the normal mice after administration of genistein: first, the proliferation suppression of BMHCs was observed and most cells were arrested in G0/G1 phase on day 1; second, progression of cells from G0/G1 phase into S phase was observed, accumulation of cells in S phase on day 2, and back to the normal level on day 4. b) Genistein, administration 24 h before irradiation, decreased the percentage of BMHCs in G0/G1 phase and increased cell proliferation. Moreover, genistein up-regulated the protein and mRNA expressions of bcl-2 in BMHCs in the irradiated mice. Conclusions: It was shown that changing with cell cycle, strengthening of radioresistant, suppressing of radiation-induced apoptosis, and enhancing of proliferation and differentiation of BMHCs maybe the underlying mechanisms for genistein protection of hematopoietic system against radiation damage. (authors)

  20. 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.

  1. Study on the characteristics of cell-cycle perturbation in hela cell exposed to continuous β irradiation of 32P

    International Nuclear Information System (INIS)

    In an attempt to understand radiobiological basis for targeted radiotherapy in oncology, the cell cycle perturbations have studied in Hela cell lines after exposed to different doses and dose-rate of 32P radiation. Asynchronous Hela cells, cultured in vitro, were exposed to β radiation from radioactive filter papers (absorbed 32P) which were put close under culture plate of growing monolayer of Hela cells. The characteristic radiation response to different dose, dose-rate and radiation time was evaluated through cell cycle perturbation studied by flow cytometry. Cell cycle status showed G2 phase blockage in a way of dose dependence, a plateau of G2 block can be recognized at about 24h. Interestingly, the G2 phase declined even though the accumulated doses increased as the time of radiation prolonged. This result suggested that the cell cycle progress could not be inhibited completely when exposed to continuous radiation, rather it seems to be controlled somehow by the nature of cell cycle itself for a certain cell line. G2 blockage, one of the major changes caused by β radiation, is dose-dependent, but the time reaching the plateau of G2 phase blockage is most likely related with the intrinsic nature of cell cycle

  2. Do progressive goverments undertake different debt burdens? Partisan vs. electoral cycles

    OpenAIRE

    I.M. García-Sánchez; J. M. Prado-Lorenzo; B. Cuadrado-Ballesteros

    2011-01-01

    Public debt has traditionally been explained mainly by two political factors: a progressive ideology and the electoral cycle. The aim of this paper is to demonstrate how these two factors influence the behavior of Spanish local governments as regards indebtedness, and also how indebtedness is influenced by the interaction of ideology and the electoral cycle.Different dependence models were estimated using panel data methodology based on a sample comprised of Spanish provincial capitals and to...

  3. The Hematopoietic Transcription Factor AML1 (RUNX1) Is Negatively Regulated by the Cell Cycle Protein Cyclin D3

    OpenAIRE

    Peterson, Luke F.; Boyapati, Anita; Ranganathan, Velvizhi; Iwama, Atsushi; Tenen, Daniel G.; Tsai, Schickwann; Zhang, Dong-Er

    2005-01-01

    The family of cyclin D proteins plays a crucial role in the early events of the mammalian cell cycle. Recent studies have revealed the involvement of AML1 transactivation activity in promoting cell cycle progression through the induction of cyclin D proteins. This information in combination with our previous observation that a region in AML1 between amino acids 213 and 289 is important for its function led us to investigate prospective proteins associating with this region. We identified cycl...

  4. Bach1 Induces Endothelial Cell Apoptosis and Cell-Cycle Arrest through ROS Generation

    Science.gov (United States)

    Wang, Xinhong; Liu, Junxu; Jiang, Li; Wei, Xiangxiang; Niu, Cong; Wang, Rui; Zhang, Jianyi; Yao, Kang

    2016-01-01

    The transcription factor BTB and CNC homology 1 (Bach1) regulates genes involved in the oxidative stress response and cell-cycle progression. We have recently shown that Bach1 impairs cell proliferation and promotes apoptosis in cultured endothelial cells (ECs), but the underlying mechanisms are largely uncharacterized. Here we demonstrate that Bach1 upregulation impaired the blood flow recovery from hindlimb ischemia and this effect was accompanied both by increases in reactive oxygen species (ROS) and cleaved caspase 3 levels and by declines in the expression of cyclin D1 in the injured tissues. We found that Bach1 overexpression induced mitochondrial ROS production and caspase 3-dependent apoptosis and its depletion attenuated H2O2-induced apoptosis in cultured human microvascular endothelial cells (HMVECs). Bach1-induced apoptosis was largely abolished when the cells were cultured with N-acetyl-l-cysteine (NAC), a ROS scavenger. Exogenous expression of Bach1 inhibited the cell proliferation and the expression of cyclin D1, induced an S-phase arrest, and increased the expression of cyclin E2, which were partially blocked by NAC. Taken together, our results suggest that Bach1 suppresses cell proliferation and induces cell-cycle arrest and apoptosis by increasing mitochondrial ROS production, suggesting that Bach1 may be a promising treatment target for the treatment of vascular diseases. PMID:27057283

  5. Cell survival, cell death and cell cycle pathways are interconnected: Implications for cancer therapy

    DEFF Research Database (Denmark)

    Maddika, S; Ande, SR; Panigrahi, S;

    2007-01-01

    The partial cross-utilization of molecules and pathways involved in opposing processes like cell survival, proliferation and cell death, assures that mutations within one signaling cascade will also affect the other opposite process at least to some extent, thus contributing to homeostatic...... regulatory circuits. This review highlights some of the connections between opposite-acting pathways. Thus, we discuss the role of cyclins in the apoptotic process, and in the regulation of cell proliferation. CDKs and their inhibitors like the INK4-family (p16(Ink4a), p15(Ink4b), p18(Ink4c), p19(Ink4d...... highlighted both for their apoptosis-regulating capacity and also for their effect on the cell cycle progression. The PI3-K/Akt cell survival pathway is shown as regulator of cell metabolism and cell survival, but examples are also provided where aberrant activity of the pathway may contribute to the...

  6. RCC1-dependent activation of Ran accelerates cell cycle and DNA repair, inhibiting DNA damage-induced cell senescence.

    Science.gov (United States)

    Cekan, Pavol; Hasegawa, Keisuke; Pan, Yu; Tubman, Emily; Odde, David; Chen, Jin-Qiu; Herrmann, Michelle A; Kumar, Sheetal; Kalab, Petr

    2016-04-15

    The coordination of cell cycle progression with the repair of DNA damage supports the genomic integrity of dividing cells. The function of many factors involved in DNA damage response (DDR) and the cell cycle depends on their Ran GTPase-regulated nuclear-cytoplasmic transport (NCT). The loading of Ran with GTP, which is mediated by RCC1, the guanine nucleotide exchange factor for Ran, is critical for NCT activity. However, the role of RCC1 or Ran⋅GTP in promoting cell proliferation or DDR is not clear. We show that RCC1 overexpression in normal cells increased cellular Ran⋅GTP levels and accelerated the cell cycle and DNA damage repair. As a result, normal cells overexpressing RCC1 evaded DNA damage-induced cell cycle arrest and senescence, mimicking colorectal carcinoma cells with high endogenous RCC1 levels. The RCC1-induced inhibition of senescence required Ran and exportin 1 and involved the activation of importin β-dependent nuclear import of 53BP1, a large NCT cargo. Our results indicate that changes in the activity of the Ran⋅GTP-regulated NCT modulate the rate of the cell cycle and the efficiency of DNA repair. Through the essential role of RCC1 in regulation of cellular Ran⋅GTP levels and NCT, RCC1 expression enables the proliferation of cells that sustain DNA damage. PMID:26864624

  7. Developing a Multi-Year Learning Progression for Carbon Cycling in Socio-Ecological Systems

    Science.gov (United States)

    Mohan, Lindsey; Chen, Jing; Anderson, Charles W.

    2009-01-01

    This study reports on our steps toward achieving a conceptually coherent and empirically validated learning progression for carbon cycling in socio-ecological systems. It describes an iterative process of designing and analyzing assessment and interview data from students in upper elementary through high school. The product of our development…

  8. New progress of research on water cycle in atmosphere in China

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    New progresses are introduced briefly about the water cycle study on atmosphere of China made in recent years. The introduction includes eight aspects as follows: 1) precipitation characteristics, 2) stability of climatic system, 3) precipitation sensitive region, 4) regional evaporation and evapotranspiration, 5) water surface evaporation, 6) vegetation transpiration, 7) cloud physics, and 8) vapor source.

  9. A role for transcriptional repression of p21CIP1 by c-Myc in overcoming transforming growth factor β-induced cell-cycle arrest

    OpenAIRE

    Claassen, Gisela F.; Hann, Stephen R.

    2000-01-01

    c-Myc plays a vital role in cell-cycle progression. Deregulated expression of c-Myc can overcome cell-cycle arrest in order to promote cellular proliferation. Transforming growth factor β (TGFβ) treatment of immortalized human keratinocyte cells inhibits cell-cycle progression and is characterized by down-regulation of c-Myc followed by up-regulation of p21CIP1. A direct role of c-Myc in this pathway was demonstrated by the observation that ectopic expression of c-Myc overcame the cell-cycle ...

  10. Using single cell cultivation system for on-chip monitoring of the interdivision timer in Chlamydomonas reinhardtii cell cycle

    Directory of Open Access Journals (Sweden)

    Soloviev Mikhail

    2010-09-01

    Full Text Available Abstract Regulation of cell cycle progression in changing environments is vital for cell survival and maintenance, and different regulation mechanisms based on cell size and cell cycle time have been proposed. To determine the mechanism of cell cycle regulation in the unicellular green algae Chlamydomonas reinhardtii, we developed an on-chip single-cell cultivation system that allows for the strict control of the extracellular environment. We divided the Chlamydomonas cell cycle into interdivision and division phases on the basis of changes in cell size and found that, regardless of the amount of photosynthetically active radiation (PAR and the extent of illumination, the length of the interdivision phase was inversely proportional to the rate of increase of cell volume. Their product remains constant indicating the existence of an 'interdivision timer'. The length of the division phase, in contrast, remained nearly constant. Cells cultivated under light-dark-light conditions did not divide unless they had grown to twice their initial volume during the first light period. This indicates the existence of a 'commitment sizer'. The ratio of the cell volume at the beginning of the division phase to the initial cell volume determined the number of daughter cells, indicating the existence of a 'mitotic sizer'.

  11. Tea pigments induce cell-cycle arrest and apoptosis in HepG2 cells

    Institute of Scientific and Technical Information of China (English)

    Xu-Dong Jia; Chi Han; Jun-Shi Chen

    2005-01-01

    AIM: To investigate the molecular mechanisms by which tea pigments exert preventive effects on liver carcinogenesis.METHODS: HepG2 cells were seeded at a density of 5×105/well in six-well culture dishes and incubated overnight. The cells then were treated with various concentrations of tea pigments over 3 d, harvested by trypsinization, and counted using a hemocytometer. Flow cytometric analysis was performed by a flow cytometer after propidium iodide labeling. Bcl-2 and p21WAF1 proteins were determined by Western blotting. In addition, DNA laddering assay was performed on treated and untreated cultured HepG2 cells.RESULTS: Tea pigments inhibited the growth of HepG2 cells in a dose-dependent manner. Flow-cytometric analysis showed that tea pigments arrested cell cycle progression at G1 phase. DNA laddering was used to investigate apoptotic cell death, and the result showed that 100 mg/L of tea pigments caused typical DNA laddering. Our study also showed that tea pigments induced upregulation of p21WAF1 protein and downregulation of Bcl-2 protein.CONCLUSION: Tea pigments induce cell-cycle arrest and apoptosis. Tea pigments may be used as an ideal chemopreventive agent.

  12. 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

  13. 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

  14. Limit Cycle Oscillations in Pacemaker Cells

    CERN Document Server

    Endresen, L P; Endresen, Lars Petter; Skarland, Nils

    1999-01-01

    In recent decades, several mathematical models describing the pacemaker activity of the rabbit sinoatrial node have been developed. We demonstrate that it is not possible to establish the existence, uniqueness, and stability of a limit cycle oscillation in those models. Instead we observe an infinite number of limit cycles. We then display numerical results from a new model, with a limit cycle that can be reached from many different initial conditions.

  15. Radiation response and cell cycle regulation of p53 rescued malignant keratinocytes

    International Nuclear Information System (INIS)

    Mutations in the tumor suppressor gene p53 were found in more than 90% of all human squamous cell carcinomas (SCC). To study the function of p53 in a keratinocyte background, a tetracycline-controlled p53 transgene was introduced into a human SCC cell line (SCC15), lacking endogenous p53. Conditional expression of wild-type p53 protein upon withdrawal of tetracycline was accompanied with increased expression of p21WAF1/Cip1 resulting in reduced cell proliferation. Flow-cytometric analysis revealed that these cells were transiently arrested in the G1/S phase of the cell cycle. However, when SCC15 cells expressing p53 were exposed to ionizing radiation (IR), a clear shift from a G1/S to a G2/M cell cycle arrest was observed. This effect was greatly depending on the presence of wild-type p53, as it was not observed to the same extent in SCC15 cells lacking p53. Unexpectedly, the p53- and IR-dependent G2/M cell cycle arrest in the keratinocyte background was not depending on increased expression or stabilization of 14-3-3σ, a p53-regulated effector of G2/M progression in colorectal cancer cells. In keratinocytes, 14-3-3σ (stratifin) is involved in terminal differentiation and its cell cycle function in this cell type might diverge from the one it fulfills in other cellular backgrounds

  16. Cell cycle arrest biomarkers in human lung cancer cells after treatment with selenium in culture.

    Science.gov (United States)

    Swede, Helen; Dong, Yan; Reid, Mary; Marshall, James; Ip, Clement

    2003-11-01

    In the planning of future intervention trials using chemopreventive agents against lung cancer, it is critical to evaluate the effect on biomarkers implicated specifically in lung carcinogenesis. With the use of the H520 and H522 human lung cancer cell lines, the present study showed that treatment with selenium (in the form of methylseleninic acid) inhibited cell growth, arrested cell cycle progression at G(1), and induced apoptosis as a late event. Because H520 cells were more sensitive to selenium than H522 cells (IC(50) of MSA was 2.5 or 10 micro M for H520 or H522 cells, respectively, at 24 h), a panel of nine cell cycle regulatory proteins known to be involved in G(1)-->S transition was assessed by Western analysis using whole cell lysate from H520 cells. These nine proteins (DP1, cdc25A, cyclin A, cyclin B(1), cyclin D(1), cdk1, cdk5, p21(WAF1), and GADD153) have been reported previously by our laboratory to be modulated by MSA in human breast and prostate cancer cells. Our data showed that only four (DP1, cdc25A, p21(WAF1), and GADD153) of nine biomarkers produced the expected changes after treatment of lung cancer cells with MSA. This finding raises the possibility that the molecular targets sensitive to selenium modulation may be tissue specific. Thus, the selection of selenium biomarkers for evaluation in an intervention trial must be based on empirical data derived from the cancer cell type of interest. PMID:14652289

  17. Cell Sorting of Neural Stem and Progenitor Cells from the Adult Mouse Subventricular Zone and Live-imaging of their Cell Cycle Dynamics.

    Science.gov (United States)

    Daynac, Mathieu; Morizur, Lise; Kortulewski, Thierry; Gauthier, Laurent R; Ruat, Martial; Mouthon, Marc-André; Boussin, François D

    2015-01-01

    Neural stem cells (NSCs) in the subventricular zone of the lateral ventricles (SVZ) sustain olfactory neurogenesis throughout life in the mammalian brain. They successively generate transit amplifying cells (TACs) and neuroblasts that differentiate into neurons once they integrate the olfactory bulbs. Emerging fluorescent activated cell sorting (FACS) techniques have allowed the isolation of NSCs as well as their progeny and have started to shed light on gene regulatory networks in adult neurogenic niches. We report here a cell sorting technique that allows to follow and distinguish the cell cycle dynamics of the above-mentioned cell populations from the adult SVZ with a LeX/EGFR/CD24 triple staining. Isolated cells are then plated as adherent cells to explore in details their cell cycle progression by time-lapse video microscopy. To this end, we use transgenic Fluorescence Ubiquitination Cell Cycle Indicator (FUCCI) mice in which cells are red-fluorescent during G1 phase due to a G1 specific red-Cdt1 reporter. This method has recently revealed that proliferating NSCs progressively lengthen their G1 phase during aging, leading to neurogenesis impairment. This method is easily transposable to other systems and could be of great interest for the study of the cell cycle dynamics of brain cells in the context of brain pathologies. PMID:26436641

  18. Targeting Cell Cycle Proteins in Breast Cancer Cells with siRNA by Using Lipid-Substituted Polyethylenimines.

    Science.gov (United States)

    Parmar, Manoj B; Aliabadi, Hamidreza Montazeri; Mahdipoor, Parvin; Kucharski, Cezary; Maranchuk, Robert; Hugh, Judith C; Uludağ, Hasan

    2015-01-01

    The cell cycle proteins are key regulators of cell cycle progression whose deregulation is one of the causes of breast cancer. RNA interference (RNAi) is an endogenous mechanism to regulate gene expression and it could serve as the basis of regulating aberrant proteins including cell cycle proteins. Since the delivery of small interfering RNA (siRNA) is a main barrier for implementation of RNAi therapy, we explored the potential of a non-viral delivery system, 2.0 kDa polyethylenimines substituted with linoleic acid and caprylic acid, for this purpose. Using a library of siRNAs against cell cycle proteins, we identified cell division cycle protein 20 (CDC20), a recombinase RAD51, and serine-threonine protein kinase CHEK1 as effective targets for breast cancer therapy, and demonstrated their therapeutic potential in breast cancer MDA-MB-435, MDA-MB-231, and MCF7 cells with respect to another well-studied cell cycle protein, kinesin spindle protein. We also explored the efficacy of dicer-substrate siRNA (DsiRNA) against CDC20, RAD51, and CHEK1, where a particular DsiRNA against CDC20 showed an exceptionally high inhibition of cell growth in vitro. There was no apparent effect of silencing selected cell cycle proteins on the potency of the chemotherapy drug doxorubicin. The efficacy of DsiRNA against CDC20 was subsequently assessed in a xenograft model, which indicated a reduced tumor growth as a result of CDC20 DsiRNA therapy. The presented study highlighted specific cell cycle protein targets critical for breast cancer therapy, and provided a polymeric delivery system for their effective down-regulation. PMID:25763370

  19. 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…

  20. Branched signal wiring of an essential bacterial cell-cycle phosphotransfer protein

    OpenAIRE

    Blair, Jimmy A.; Xu, Qingping; Childers, W. Seth; Mathews, Irimpan I.; Kern, Justin W.; Eckart, Michael; Deacon, Ashley M.; Shapiro, Lucy

    2013-01-01

    Vital to bacterial survival is the faithful propagation of cellular signals, and in Caulobacter crescentus ChpT is an essential mediator within the cell cycle circuit. ChpT functions as a histidine-containing phosphotransfer protein (HPt) that shuttles a phosphoryl group from the receiver domain of CckA, the upstream hybrid histidine kinase (HK), to one of two downstream response regulators (RRs)—CtrA or CpdR—that controls cell cycle progression. To understand how ChpT interacts with multiple...

  1. Progress in Finite Time Thermodynamic Studies for Internal Combustion Engine Cycles

    Directory of Open Access Journals (Sweden)

    Yanlin Ge

    2016-04-01

    Full Text Available On the basis of introducing the origin and development of finite time thermodynamics (FTT, this paper reviews the progress in FTT optimization for internal combustion engine (ICE cycles from the following four aspects: the studies on the optimum performances of air standard endoreversible (with only the irreversibility of heat resistance and irreversible ICE cycles, including Otto, Diesel, Atkinson, Brayton, Dual, Miller, Porous Medium and Universal cycles with constant specific heats, variable specific heats, and variable specific ratio of the conventional and quantum working fluids (WFs; the studies on the optimum piston motion (OPM trajectories of ICE cycles, including Otto and Diesel cycles with Newtonian and other heat transfer laws; the studies on the performance limits of ICE cycles with non-uniform WF with Newtonian and other heat transfer laws; as well as the studies on the performance simulation of ICE cycles. In the studies, the optimization objectives include work, power, power density, efficiency, entropy generation rate, ecological function, and so on. The further direction for the studies is explored.

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

    Energy Technology Data Exchange (ETDEWEB)

    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.

  3. Systematic Analysis of Cell Cycle Effects of Common Drugs Leads to the Discovery of a Suppressive Interaction between Gemfibrozil and Fluoxetine

    OpenAIRE

    Hoose, Scott A.; Duran, Camille; Malik, Indranil; Eslamfam, Shabnam; Samantha C Shasserre; Downing, S. Sabina; Evelyn M Hoover; Dowd, Katherine E.; Smith, Roger; Polymenis, Michael

    2012-01-01

    Screening chemical libraries to identify compounds that affect overall cell proliferation is common. However, in most cases, it is not known whether the compounds tested alter the timing of particular cell cycle transitions. Here, we evaluated an FDA-approved drug library to identify pharmaceuticals that alter cell cycle progression in yeast, using DNA content measurements by flow cytometry. This approach revealed strong cell cycle effects of several commonly used pharmaceuticals. We show tha...

  4. H4 histamine receptors mediate cell cycle arrest in growth factor-induced murine and human hematopoietic progenitor cells.

    Directory of Open Access Journals (Sweden)

    Anne-France Petit-Bertron

    Full Text Available The most recently characterized H4 histamine receptor (H4R is expressed preferentially in the bone marrow, raising the question of its role during hematopoiesis. Here we show that both murine and human progenitor cell populations express this receptor subtype on transcriptional and protein levels and respond to its agonists by reduced growth factor-induced cell cycle progression that leads to decreased myeloid, erythroid and lymphoid colony formation. H4R activation prevents the induction of cell cycle genes through a cAMP/PKA-dependent pathway that is not associated with apoptosis. It is mediated specifically through H4R signaling since gene silencing or treatment with selective antagonists restores normal cell cycle progression. The arrest of growth factor-induced G1/S transition protects murine and human progenitor cells from the toxicity of the cell cycle-dependent anticancer drug Ara-C in vitro and reduces aplasia in a murine model of chemotherapy. This first evidence for functional H4R expression in hematopoietic progenitors opens new therapeutic perspectives for alleviating hematotoxic side effects of antineoplastic drugs.

  5. Levels of Ycg1 Limit Condensin Function during the Cell Cycle

    Science.gov (United States)

    Arsenault, Heather E.; Benanti, Jennifer A.

    2016-01-01

    During mitosis chromosomes are condensed to facilitate their segregation, through a process mediated by the condensin complex. Although several factors that promote maximal condensin activity during mitosis have been identified, the mechanisms that downregulate condensin activity during interphase are largely unknown. Here, we demonstrate that Ycg1, the Cap-G subunit of budding yeast condensin, is cell cycle-regulated with levels peaking in mitosis and decreasing as cells enter G1 phase. This cyclical expression pattern is established by a combination of cell cycle-regulated transcription and constitutive degradation. Interestingly, overexpression of YCG1 and mutations that stabilize Ycg1 each result in delayed cell-cycle entry and an overall proliferation defect. Overexpression of no other condensin subunit impacts the cell cycle, suggesting that Ycg1 is limiting for condensin complex formation. Consistent with this possibility, we find that levels of intact condensin complex are reduced in G1 phase compared to mitosis, and that increased Ycg1 expression leads to increases in both levels of condensin complex and binding to chromatin in G1. Together, these results demonstrate that Ycg1 levels limit condensin function in interphase cells, and suggest that the association of condensin with chromosomes must be reduced following mitosis to enable efficient progression through the cell cycle. PMID:27463097

  6. In situ cell cycle phase determination using Raman spectroscopy

    Science.gov (United States)

    Oshima, Yusuke; Takenaka, Tatsuji; Sato, Hidetoshi; Furihata, Chie

    2010-02-01

    Raman spectroscopy is a powerful tool for analysis of the chemical composition in living tissue and cells without destructive processes such as fixation, immunostaining, and fluorescence labeling. Raman microspectroscopic technique enables us to obtain a high quality spectrum from a single living cell. We demonstrated in situ cell cycle analysis with Raman microspectroscopy with the excitation wavelength of 532 nm. Cell cycle phases, G0/G1 and G2/M were able to be identified in the present study. The result of in situ Raman analysis was evaluated with flow cytometry analysis. Although the Raman spectra of living cells showed complex patterns during cell cycle, several Raman bands could be useful as markers for the cell cycle identification. A single cell analysis using Raman microspectroscopy predicted a possibility to observe directly molecular dynamics intracellular molecules of proteins, lipids and nucleic acids. Our current study focused on cytoplasm region and resonant Raman signals of cytochrome c in mitochondrion, and discussed how the Raman signals from cellular components contribute to the Raman spectral changes in cell cycle change in the human living cell (lung cancer cell).

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

    International Nuclear Information System (INIS)

    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

  8. 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

  9. Staphylococcal Enterotoxin O Exhibits Cell Cycle Modulating Activity

    Science.gov (United States)

    Hodille, Elisabeth; Alekseeva, Ludmila; Berkova, Nadia; Serrier, Asma; Badiou, Cedric; Gilquin, Benoit; Brun, Virginie; Vandenesch, François; Terman, David S.; Lina, Gerard

    2016-01-01

    Maintenance of an intact epithelial barrier constitutes a pivotal defense mechanism against infections. Staphylococcus aureus is a versatile pathogen that produces multiple factors including exotoxins that promote tissue alterations. The aim of the present study is to investigate the cytopathic effect of staphylococcal exotoxins SEA, SEG, SEI, SElM, SElN and SElO on the cell cycle of various human cell lines. Among all tested exotoxins only SEIO inhibited the proliferation of a broad panel of human tumor cell lines in vitro. Evaluation of a LDH release and a DNA fragmentation of host cells exposed to SEIO revealed that the toxin does not induce necrosis or apoptosis. Analysis of the DNA content of tumor cells synchronized by serum starvation after exposure to SEIO showed G0/G1 cell cycle delay. The cell cycle modulating feature of SEIO was confirmed by the flow cytometry analysis of synchronized cells exposed to supernatants of isogenic S. aureus strains wherein only supernatant of the SElO producing strain induced G0/G1 phase delay. The results of yeast-two-hybrid analysis indicated that SEIO’s potential partner is cullin-3, involved in the transition from G1 to S phase. In conclusion, we provide evidence that SEIO inhibits cell proliferation without inducing cell death, by delaying host cell entry into the G0/G1 phase of the cell cycle. We speculate that this unique cell cycle modulating feature allows SEIO producing bacteria to gain advantage by arresting the cell cycle of target cells as part of a broader invasive strategy. PMID:27148168

  10. Phase locking and multiple oscillating attractors for the coupled mammalian clock and cell cycle

    Science.gov (United States)

    Feillet, Céline; Krusche, Peter; Tamanini, Filippo; Janssens, Roel C.; Downey, Mike J.; Martin, Patrick; Teboul, Michèle; Saito, Shoko; Lévi, Francis A.; Bretschneider, Till; van der Horst, Gijsbertus T. J.; Delaunay, Franck; Rand, David A.

    2014-01-01

    Daily synchronous rhythms of cell division at the tissue or organism level are observed in many species and suggest that the circadian clock and cell cycle oscillators are coupled. For mammals, despite known mechanistic interactions, the effect of such coupling on clock and cell cycle progression, and hence its biological relevance, is not understood. In particular, we do not know how the temporal organization of cell division at the single-cell level produces this daily rhythm at the tissue level. Here we use multispectral imaging of single live cells, computational methods, and mathematical modeling to address this question in proliferating mouse fibroblasts. We show that in unsynchronized cells the cell cycle and circadian clock robustly phase lock each other in a 1:1 fashion so that in an expanding cell population the two oscillators oscillate in a synchronized way with a common frequency. Dexamethasone-induced synchronization reveals additional clock states. As well as the low-period phase-locked state there are distinct coexisting states with a significantly higher period clock. Cells transition to these states after dexamethasone synchronization. The temporal coordination of cell division by phase locking to the clock at a single-cell level has significant implications because disordered circadian function is increasingly being linked to the pathogenesis of many diseases, including cancer. PMID:24958884

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

    DEFF Research Database (Denmark)

    Rokni, Masoud

    2014-01-01

    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......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...... 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...

  12. 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.

  13. 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.

  14. A revision of the Dictyostelium discoideum cell cycle.

    Science.gov (United States)

    Weijer, C J; Duschl, G; David, C N

    1984-08-01

    We have investigated the Dictyostelium discoideum cell cycle using fluorometric determinations of cellular and nuclear DNA contents in exponentially growing cultures and in synchronized cultures. Almost all cells are in G2 during both growth and development. There is no G1 period, S phase is less than 0.5 h, and G2 has an average length of 6.5 h in axenically grown cells. Mitochondrial DNA, which constitutes about half of the total DNA, is replicated throughout the cell cycle. There is no difference in the nuclear DNA contents of axenically grown and bacterially grown cells. Thus the long cell cycle in axenically grown cells is due to a lengthening of the G2 phase. PMID:6389576

  15. Artesunate Reduces Proliferation, Interferes DNA Replication and Cell Cycle and Enhances Apoptosis in Vascular Smooth Muscle Cells

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    This study examined the effect of artesunate (Art) on the proliferation, DNA replication, cell cycles and apoptosis of vascular smooth muscle cells (VSMCs). Primary cultures of VSMCs were established from aortas of mice and artesunate of different concentrations was added into the medium. The number of VSMCs was counted and the curve of cell growth was recorded.The activity of VSMCs was assessed by using MTT method and inhibitory rate was calculated.DNA replication was evaluated by [3 H]-TdR method and apoptosis by DNA laddering and HE staining. Flowmetry was used for simultaneous analysis of cell apoptosis and cell cycles. Compared with the control group, VSMCs proliferation in Art interfering groups were inhibited and [3H]-TdR incorprating rate were decreased as well as cell apoptosis was induced. The progress of cell cycle was blocked in G0/G1 by Art in a dose-dependent manner. It is concluded that Art inhibits VSMCs proliferation by disturbing DNA replication, inducing cell apoptosis and blocking cell cycle in G0/G1 phase.

  16. 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.

  17. Molecular signatures of cell cycle transcripts in the pathogenesis of Glial tumors

    Directory of Open Access Journals (Sweden)

    Bhattacharya Rabindra

    2004-01-01

    Full Text Available Abstract Background Astrocytic brain tumors are among the most lethal and morbid tumors of adults, often occurring during the prime of life. These tumors form an interesting group of cancer to understand the molecular mechanism of pathogenesis. Histological grading of Astrocytoma based on WHO classification does not provide complete information on the proliferation potential and biological behavior of the tumors. It is known that cancer results from the disruption of the orderly regulated cycle of replication and division. In the present study, we made an attempt to identify the cell cycle signatures and their involvement in the clinical aggressiveness of gliomas. Methods The variation in expression of various cell cycle genes was studied in different stages of glial tumor progression (low and high grades, and the results were compared with their corresponding expression levels in the normal brain tissue. Macroarray analysis was used for the purpose. Results Macroarray analysis of 114 cell cycle genes in different grades of glioma indicated differential expression pattern in 34% of the gene transcripts, when compared to the normal tissue. Majority of the transcripts belong to the intracellular kinase networks, cell cycle regulating kinases, transcription factors and transcription activators. Conclusion Based on the observation in the expression pattern in low grade and high grade gliomas, it can be suggested that the upregulation of cell cycle activators are seen as an early event in glioma; however, in malignancy it is not the cell cycle activators alone, which are involved in tumorigenesis. Understanding the molecular details of cell cycle regulation and checkpoint abnormalities in cancer could offer an insight into potential therapeutic strategies.

  18. Cancer stem cell targeted therapy: progress amid controversies

    OpenAIRE

    Wang, Tao; Shigdar, Sarah; Gantier, Michael P.; Hou, Yingchun; Wang, Li; Li, Yong; Shamaileh, Hadi Al; Yin, Wang; ZHOU, SHU-FENG; Zhao, Xinhan; Duan, Wei

    2015-01-01

    Although cancer stem cells have been well characterized in numerous malignancies, the fundamental characteristics of this group of cells, however, have been challenged by some recent observations: cancer stem cells may not necessary to be rare within tumors; cancer stem cells and non-cancer stem cells may undergo reversible phenotypic changes; and the cancer stem cells phenotype can vary substantially between patients. Here the current status and progresses of cancer stem cells theory is illu...

  19. The Architectural Organization of Human Stem Cell Cycle Regulatory Machinery

    OpenAIRE

    Stein, Gary S.; Stein, Janet L.; van Wijnen, Andre J.; Lian, Jane B.; Montecino, Martin; Medina, Ricardo(Instituto de Matemática e Computação, Universidade Federal de Itajubá, Itajubá, Minas Gerais, Brazil); Kapinas, Kristie; Ghule, Prachi; Grandy, Rodrigo; Zaidi, Sayyed K.; Becker, Klaus A.

    2012-01-01

    Two striking features of human embryonic stem cells that support biological activity are an abbreviated cell cycle and reduced complexity to nuclear organization. The potential implications for rapid proliferation of human embryonic stem cells within the context of sustaining pluripotency, suppressing phenotypic gene expression and linkage to simplicity in the architectural compartmentalization of regulatory machinery in nuclear microenvironments is explored. Characterization of the molecular...

  20. Role of DNA methylation in cell cycle arrest induced by Cr (VI in two cell lines.

    Directory of Open Access Journals (Sweden)

    Jianlin Lou

    Full Text Available Hexavalent chromium [Cr(IV], a well-known industrial waste product and an environmental pollutant, is recognized as a human carcinogen. But its mechanisms of carcinogenicity remain unclear, and recent studies suggest that DNA methylation may play an important role in the carcinogenesis of Cr(IV. The aim of our study was to investigate the effects of Cr(IV on cell cycle progress, global DNA methylation, and DNA methylation of p16 gene. A human B lymphoblastoid cell line and a human lung cell line A549 were exposed to 5-15 µM potassium dichromate or 1.25-5 µg/cm² lead chromate for 2-24 hours. Cell cycle was arrested at G₁ phase by both compounds in 24 hours exposure group, but global hypomethylation occurred earlier than cell cycle arrest, and the hypomethylation status maintained for more than 20 hours. The mRNA expression of p16 was significantly up-regulated by Cr(IV, especially by potassium dichromate, and the mRNA expression of cyclin-dependent kinases (CDK4 and CDK6 was significantly down-regulated. But protein expression analysis showed very little change of p16 gene. Both qualitative and quantitative results showed that DNA methylation status of p16 remained unchanged. Collectively, our data suggested that global hypomethylation was possibly responsible for Cr(IV-induced G₁ phase arrest, but DNA methylation might not be related to up-regulation of p16 gene by Cr(IV.

  1. Dynamic Pax6 expression during the neurogenic cell cycle influences proliferation and cell fate choices of retinal progenitors

    Directory of Open Access Journals (Sweden)

    Yang Xian-Jie

    2009-08-01

    Full Text Available Abstract Background The paired homeobox protein Pax6 is essential for proliferation and pluripotency of retinal progenitors. However, temporal changes in Pax6 protein expression associated with the generation of various retinal neurons have not been characterized with regard to the cell cycle. Here, we examine the dynamic changes of Pax6 expression among chicken retinal progenitors as they progress through the neurogenic cell cycle, and determine the effects of altered Pax6 levels on retinogenesis. Results We provide evidence that during the preneurogenic to neurogenic transition, Pax6 protein levels in proliferating progenitor cells are down-regulated. Neurogenic retinal progenitors retain a relatively low level of Pax6 protein, whereas postmitotic neurons either elevate or extinguish Pax6 expression in a cell type-specific manner. Cell imaging and cell cycle analyses show that neurogenic progenitors in the S phase of the cell cycle contain low levels of Pax6 protein, whereas a subset of progenitors exhibits divergent levels of Pax6 protein upon entering the G2 phase of the cell cycle. We also show that M phase cells contain varied levels of Pax6, and some correlate with the onset of early neuronal marker expression, forecasting cell cycle exit and cell fate commitment. Furthermore, either elevating or knocking down Pax6 attenuates cell proliferation and results in increased cell death. Reducing Pax6 decreases retinal ganglion cell genesis and enhances cone photoreceptor and amacrine interneuron production, whereas elevating Pax6 suppresses cone photoreceptor and amacrine cell fates. Conclusion These studies demonstrate for the first time quantitative changes in Pax6 protein expression during the preneurogenic to neurogenic transition and during the neurogenic cell cycle. The results indicate that Pax6 protein levels are stringently controlled in proliferating progenitors. Maintaining a relatively low Pax6 protein level is necessary for S phase

  2. Large scale spontaneous synchronization of cell cycles in amoebae

    Science.gov (United States)

    Segota, Igor; Boulet, Laurent; Franck, Carl

    2014-03-01

    Unicellular eukaryotic amoebae Dictyostelium discoideum are generally believed to grow in their vegetative state as single cells until starvation, when their collective aspect emerges and they differentiate to form a multicellular slime mold. While major efforts continue to be aimed at their starvation-induced social aspect, our understanding of population dynamics and cell cycle in the vegetative growth phase has remained incomplete. We show that substrate-growtn cell populations spontaneously synchronize their cell cycles within several hours. These collective population-wide cell cycle oscillations span millimeter length scales and can be completely suppressed by washing away putative cell-secreted signals, implying signaling by means of a diffusible growth factor or mitogen. These observations give strong evidence for collective proliferation behavior in the vegetative state and provide opportunities for synchronization theories beyond classic Kuramoto models.

  3. Inhibition of protein kinase B activity induces cell cycle arrest and apoptosis during early G₁ phase in CHO cells.

    Science.gov (United States)

    van Opstal, Angélique; Bijvelt, José; van Donselaar, Elly; Humbel, Bruno M; Boonstra, Johannes

    2012-04-01

    Inhibition of PKB (protein kinase B) activity using a highly selective PKB inhibitor resulted in inhibition of cell cycle progression only if cells were in early G1 phase at the time of addition of the inhibitor, as demonstrated by time-lapse cinematography. Addition of the inhibitor during mitosis up to 2 h after mitosis resulted in arrest of the cells in early G1 phase, as deduced from the expression of cyclins D and A and incorporation of thymidine. After 24 h of cell cycle arrest, cells expressed the cleaved caspase-3, a central mediator of apoptosis. These results demonstrate that PKB activity in early G1 phase is required to prevent the induction of apoptosis. Using antibodies, it was demonstrated that active PKB translocates to the nucleus during early G1 phase, while an even distribution of PKB was observed through cytoplasm and nucleus during the end of G1 phase. PMID:22251027

  4. Responses of genes involved in cell cycle control to diverse DNA damaging chemicals in human lung adenocarcinoma A549 cells

    Directory of Open Access Journals (Sweden)

    Gooderham Nigel J

    2005-08-01

    Full Text Available Abstract Background Many anticancer agents and carcinogens are DNA damaging chemicals and exposure to such chemicals results in the deregulation of cell cycle progression. The molecular mechanisms of DNA damage-induced cell cycle alteration are not well understood. We have studied the effects of etoposide (an anticancer agent, cryptolepine (CLP, a cytotoxic alkaloid, benzo [a]pyrene (BaP, a carcinogenic polycyclic aromatic hydrocarbon and 2-amino-1-methyl-6-phenylimidazo [4,5-b]pyridine (PhIP, a cooked-meat derived carcinogen on the expression of cell cycle regulatory genes to understand the molecular mechanisms of the cell cycle disturbance. Results A549 cells were treated with DMSO or chemicals for up to 72 h and periodically sampled for cell cycle analysis, mRNA and protein expression. DMSO treated cells showed a dominant G1 peak in cell cycle at all times examined. Etoposide and CLP both induced G2/M phase arrest yet the former altered the expression of genes functioning at multiple phases, whilst the latter was more effective in inhibiting the expression of genes in G2-M transition. Both etoposide and CLP induced an accumulation of p53 protein and upregulation of p53 transcriptional target genes. Neither BaP nor PhIP had substantial phase-specific cell cycle effect, however, they induced distinctive changes in gene expression. BaP upregulated the expression of CYP1B1 at 6–24 h and downregulated many cell cycle regulatory genes at 48–72 h. By contrast, PhIP increased the expression of many cell cycle regulatory genes. Changes in the expression of key mRNAs were confirmed at protein level. Conclusion Our experiments show that DNA damaging agents with different mechanisms of action induced distinctive changes in the expression pattern of a panel of cell cycle regulatory genes. We suggest that examining the genomic response to chemical exposure provides an exceptional opportunity to understand the molecular mechanism involved in cellular

  5. Cell cycle deregulation by methyl isocyanate: Implications in liver carcinogenesis.

    Science.gov (United States)

    Panwar, Hariom; Raghuram, Gorantla V; Jain, Deepika; Ahirwar, Alok K; Khan, Saba; Jain, Subodh K; Pathak, Neelam; Banerjee, Smita; Maudar, Kewal K; Mishra, Pradyumna K

    2014-03-01

    Liver is often exposed to plethora of chemical toxins. Owing to its profound physiological role and central function in metabolism and homeostasis, pertinent succession of cell cycle in liver epithelial cells is of prime importance to maintain cellular proliferation. Although recent evidence has displayed a strong association between exposures to methyl isocyanate (MIC), one of the most toxic isocyanates, and neoplastic transformation, molecular characterization of the longitudinal effects of MIC on cell cycle regulation has never been performed. Here, we sequentially delineated the status of different proteins arbitrating the deregulation of cell cycle in liver epithelial cells treated with MIC. Our data reaffirms the oncogenic capability of MIC with elevated DNA damage response proteins pATM and γ-H2AX, deregulation of DNA damage check point genes CHK1 and CHK2, altered expression of p53 and p21 proteins involved in cell cycle arrest with perturbation in GADD-45 expression in the treated cells. Further, alterations in cyclin A, cyclin E, CDK2 levels along with overexpression of mitotic spindle checkpoints proteins Aurora A/B, centrosomal pericentrin protein, chromosomal aberrations, and loss of Pot1a was observed. Thus, MIC impacts key proteins involved in cell cycle regulation to trigger genomic instability as a possible mechanism of developmental basis of liver carcinogenesis. PMID:22223508

  6. 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.

  7. Progress in batteries and solar cells. Volume 5

    International Nuclear Information System (INIS)

    The 89 articles in this book are on research in batteries, solar cells and fuel cells. Topics include uses of batteries in electric powered vehicles, load management in power plants, batteries for miniature electronic devices, electrochemical processes, and various electrode and electrolyte materials, including organic compounds. Types of batteries discussed are lithium, lead-acid, manganese dioxide, Silver cells, Air cells, Nickel cells and solar cells. Problems of recharging and life cycle are also discussed

  8. 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.

  9. Targeting the cancer cell cycle by cold atmospheric plasma

    Science.gov (United States)

    Volotskova, O.; Hawley, T. S.; Stepp, M. A.; Keidar, M.

    2012-09-01

    Cold atmospheric plasma (CAP), a technology based on quasi-neutral ionized gas at low temperatures, is currently being evaluated as a new highly selective alternative addition to existing cancer therapies. Here, we present a first attempt to identify the mechanism of CAP action. CAP induced a robust ~2-fold G2/M increase in two different types of cancer cells with different degrees of tumorigenicity. We hypothesize that the increased sensitivity of cancer cells to CAP treatment is caused by differences in the distribution of cancer cells and normal cells within the cell cycle. The expression of γH2A.X (pSer139), an oxidative stress reporter indicating S-phase damage, is enhanced specifically within CAP treated cells in the S phase of the cell cycle. Together with a significant decrease in EdU-incorporation after CAP, these data suggest that tumorigenic cancer cells are more susceptible to CAP treatment.

  10. Impact of steroid hormone signals on Drosophila cell cycle during development

    Directory of Open Access Journals (Sweden)

    Quinn Leonie

    2009-01-01

    Full Text Available Abstract Metamorphosis of Drosophila involves proliferation, differentiation and death of larval tissues in order to form the adult fly. The major steroid hormone implicated in the larval-pupal transition and adult tissue modelling is ecdysone. Previous reviews have draw together studies connecting ecdysone signaling to the processes of apoptosis and differentiation. Here we discuss those reports connecting the ecdysone pulse to developmentally regulated cell cycle progression.

  11. Neurofibromatosis Type 2 Protein, NF2: An uncoventional cell cycle regulator

    OpenAIRE

    Beltrami, Sarah; Kim, Richard; Gordon, Jennifer

    2013-01-01

    Neurofibromatosis type 2 protein (NF2) is an underappreciated tumor suppressor involved in a broad range of nervous system tumors. Inactivation of the NF2 gene leads to neurofibromatosis type 2, which is characterized by multiple benign nervous system tumors and mutations in the gene have been demonstrated in many other tumor types as well. All tumors, regardless of location or grade, lack a fundamental control over cell cycle progression. Historically, NF2 is an unconventional tumor suppress...

  12. Functional cooperation between FACT and MCM is coordinated with cell cycle and differential complex formation

    Directory of Open Access Journals (Sweden)

    Lin Chih-Li

    2010-02-01

    Full Text Available Abstract Background Functional cooperation between FACT and the MCM helicase complex constitutes an integral step during DNA replication initiation. However, mode of regulation that underlies the proper functional interaction of FACT and MCM is poorly understood. Methods & Results Here we present evidence indicating that such interaction is coordinated with cell cycle progression and differential complex formation. We first demonstrate the existence of two distinct FACT-MCM subassemblies, FACT-MCM2/4/6/7 and FACT-MCM2/3/4/5. Both complexes possess DNA unwinding activity and are subject to cell cycle-dependent enzymatic regulation. Interestingly, analysis of functional attributes further suggests that they act at distinct, and possibly sequential, steps during origin establishment and replication initiation. Moreover, we show that the phosphorylation profile of the FACT-associated MCM4 undergoes a cell cycle-dependent change, which is directly correlated with the catalytic activity of the FACT-MCM helicase complexes. Finally, at the quaternary structure level, physical interaction between FACT and MCM complexes is generally dependent on persistent cell cycle and further stabilized upon S phase entry. Cessation of mitotic cycle destabilizes the complex formation and likely leads to compromised coordination and activities. Conclusions Together, our results correlate FACT-MCM functionally and temporally with S phase and DNA replication. They further demonstrate that enzymatic activities intrinsically important for DNA replication are tightly controlled at various levels, thereby ensuring proper progression of, as well as exit from, the cell cycle and ultimately euploid gene balance.

  13. Progress in portable direct methanol fuel cell

    Institute of Scientific and Technical Information of China (English)

    佘沛亮; 胡信国; 陈怀林

    2004-01-01

    The progresses in portable DMFC worldwide were reviewed, the current status of its components, catalysts, proton exchange membrane and flow field plate, the market development of portable electronic appliances, such as mobile phone, PDA and notebook were introduced.

  14. Adaptation to alkalosis induces cell cycle delay and apoptosis in cortical collecting duct cells: role of Aquaporin-2.

    Science.gov (United States)

    Rivarola, Valeria; Flamenco, Pilar; Melamud, Luciana; Galizia, Luciano; Ford, Paula; Capurro, Claudia

    2010-08-01

    Collecting ducts (CD) not only constitute the final site for regulating urine concentration by increasing apical membrane Aquaporin-2 (AQP2) expression, but are also essential for the control of acid-base status. The aim of this work was to examine, in renal cells, the effects of chronic alkalosis on cell growth/death as well as to define whether AQP2 expression plays any role during this adaptation. Two CD cell lines were used: WT- (not expressing AQPs) and AQP2-RCCD(1) (expressing apical AQP2). Our results showed that AQP2 expression per se accelerates cell proliferation by an increase in cell cycle progression. Chronic alkalosis induced, in both cells lines, a time-dependent reduction in cell growth. Even more, cell cycle movement, assessed by 5-bromodeoxyuridine pulse-chase and propidium iodide analyses, revealed a G2/M phase cell accumulation associated with longer S- and G2/M-transit times. This G2/M arrest is paralleled with changes consistent with apoptosis. All these effects appeared 24 h before and were always more pronounced in cells expressing AQP2. Moreover, in AQP2-expressing cells, part of the observed alkalosis cell growth decrease is explained by AQP2 protein down-regulation. We conclude that in CD cells alkalosis causes a reduction in cell growth by cell cycle delay that triggers apoptosis as an adaptive reaction to this environment stress. Since cell volume changes are prerequisite for the initiation of cell proliferation or apoptosis, we propose that AQP2 expression facilitates cell swelling or shrinkage leading to the activation of channels necessary to the control of these processes. PMID:20432437

  15. Cell Cycle Inhibition without Disruption of Neurogenesis Is a Strategy for Treatment of Aberrant Cell Cycle Diseases: An Update

    OpenAIRE

    Da-Zhi Liu; Ander, Bradley P.

    2012-01-01

    Since publishing our earlier report describing a strategy for the treatment of central nervous system (CNS) diseases by inhibiting the cell cycle and without disrupting neurogenesis (Liu et al. 2010), we now update and extend this strategy to applications in the treatment of cancers as well. Here, we put forth the concept of “aberrant cell cycle diseases” to include both cancer and CNS diseases, the two unrelated disease types on the surface, by focusing on a common mechanism in each aberr...

  16. Overexpression of cyclin L2 induces apoptosis and cell-cycle arrest in human lung cancer cells

    Institute of Scientific and Technical Information of China (English)

    LI Hong-li; WANG Tong-shan; LI Xiao-yu; LI Nan; HUANG Ding-zhi; CHEN Qi; BA Yi

    2007-01-01

    Background Uncontrolled cell division is one of the hallmarks of tumor growth. Researches have been focused on numerous molecules involved in this process. Cyclins are critical regulatory proteins of cell cycle progression and/or transcription. The present study aimed to investigate the anti-proliferative effect of cyclin L2, and to define its growth regulatory mechanisms using human lung adenocarcinoma cell line A549.Methods Human cyclin L2 was transfected into human lung adenocarcinoma cells (A549 cell), and was expressed in a mammalian expression vector pcDNA3.1. The effects and mechanisms of the cyclin L2 in cell growth, cell cycle analysis and apoptosis were studied by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT), flow cytometry or Western blot, respectively.Results Overexpression of cyclin L2 inhibited the growth of A549 cells. Cell cycle analysis in cells transfected with pCCNL2 revealed an increment in proportion in G0/G1 phase ((68.07 ± 4.2)%) in contrast to (60.39 ± 2.82)% of the cells transfected with mock vector. Apoptosis occurred in (7.25 ± 0.98)% cells transfected with pCCNL2, as compared with (1.25 ± 0.21)% of the mock vector control group. Cyclin L2-induced-G0/G1 arrest and apoptosis involved upregulation of caspase-3 and downregulation of Bcl-2 and survivin.Conclusion The results indicate that overexpression of cyclin L2 protein may promote efficient growth inhibition of human lung adenocarcinoma cells by inducing G0/G1 cell cycle arrest and apoptosis.

  17. Nanosecond pulsed electric fields and the cell cycle

    Science.gov (United States)

    Mahlke, Megan A.

    Exposure to nanosecond pulsed electrical fields (nsPEFs) can cause poration of external and internal cell membranes, DNA damage, and disassociation of cytoskeletal components, all of which are capable of disrupting a cell's ability to replicate. The phase of the cell cycle at the time of exposure is linked to differential sensitivities to nsPEFs across cell lines, as DNA structure, membrane elasticity, and cytoskeletal structure change dramatically during the cell cycle. Additionally, nsPEFs are capable of activating cell cycle checkpoints, which could lead to apoptosis or slow population growth. NsPEFs are emerging as a method for treating tumors via apoptotic induction; therefore, investigating the relevance of nsPEFs and the cell cycle could translate into improved efficacy in tumor treatment. Populations of Jurkat and Chinese Hamster Ovary (CHO) cells were examined post-exposure (10 ns pulse trains at 150kV/cm) by analysis of DNA content via propidium iodide staining and flow cytometric analysis at various time points (1, 6, and 12h post-exposure) to determine population distribution in cell cycle phases. Additionally, CHO and Jurkat cells were synchronized in G1/S and G2/M phases, pulsed, and analyzed to evaluate the role of cell cycle phase in survival of nsPEFs. CHO populations appeared similar to sham populations post-nsPEFs but exhibited arrest in the G1 phase at 6h after exposure. Jurkat cells exhibited increased cell death after nsPEFs compared to CHO cells but did not exhibit checkpoint arrest at any observed time point. The G1/S phase checkpoint is partially controlled by the action of p53; the lack of an active p53 response in Jurkat cells could contribute to their ability to pass this checkpoint and resist cell cycle arrest. Both cell lines exhibited increased sensitivity to nsPEFs in G2/M phase. Live imaging of CHO cells after nsPEF exposure supports the theory of G1/S phase arrest, as a reduced number of cells undergo mitosis within 24 h when

  18. Mitochondrial Regulation of Cell Cycle and Proliferation

    OpenAIRE

    Antico Arciuch, Valeria Gabriela; Elguero, María Eugenia; Poderoso, Juan José; Carreras, María Cecilia

    2012-01-01

    Eukaryotic mitochondria resulted from symbiotic incorporation of α-proteobacteria into ancient archaea species. During evolution, mitochondria lost most of the prokaryotic bacterial genes and only conserved a small fraction including those encoding 13 proteins of the respiratory chain. In this process, many functions were transferred to the host cells, but mitochondria gained a central role in the regulation of cell proliferation and apoptosis, and in the modulation of metabolism; accordingly...

  19. [Regulation of the cell cycle and the development of cancer: therapeutic prospects].

    Science.gov (United States)

    Peralta-Zaragoza, O; Bahena-Román, M; Díaz-Benítez, C E; Madrid-Marina, V

    1997-01-01

    Several genetic alterations occur during the transformation process from normal to tumor cells, that involve the loss of fidelity of processes as replication, reparation, and segregation of the genomic material. Although normal cells have defense mechanisms against cancer progression, in tumor cells different escape pathways are activated leading to tumor progression. Recent advances have permitted cancer research to focus on the identification of some of its etiological factors. The knowledge of cell cycle reveals a precise mechanism achieved by the coordinated interactions and functions of cyclin-dependent kinases, control checkpoint, and repair pathways. Furthermore, it has been demonstrated that this coordinated function can be abrogated by specific genetic changes. These findings suggest that the molecular mechanisms responsible for cellular transformation may help to identify potential targets to improve cancer therapies. PMID:9424727

  20. The cell cycle-regulated genes of Schizosaccharomyces pombe.

    Directory of Open Access Journals (Sweden)

    Anna Oliva

    2005-07-01

    Full Text Available Many genes are regulated as an innate part of the eukaryotic cell cycle, and a complex transcriptional network helps enable the cyclic behavior of dividing cells. This transcriptional network has been studied in Saccharomyces cerevisiae (budding yeast and elsewhere. To provide more perspective on these regulatory mechanisms, we have used microarrays to measure gene expression through the cell cycle of Schizosaccharomyces pombe (fission yeast. The 750 genes with the most significant oscillations were identified and analyzed. There were two broad waves of cell cycle transcription, one in early/mid G2 phase, and the other near the G2/M transition. The early/mid G2 wave included many genes involved in ribosome biogenesis, possibly explaining the cell cycle oscillation in protein synthesis in S. pombe. The G2/M wave included at least three distinctly regulated clusters of genes: one large cluster including mitosis, mitotic exit, and cell separation functions, one small cluster dedicated to DNA replication, and another small cluster dedicated to cytokinesis and division. S. pombe cell cycle genes have relatively long, complex promoters containing groups of multiple DNA sequence motifs, often of two, three, or more different kinds. Many of the genes, transcription factors, and regulatory mechanisms are conserved between S. pombe and S. cerevisiae. Finally, we found preliminary evidence for a nearly genome-wide oscillation in gene expression: 2,000 or more genes undergo slight oscillations in expression as a function of the cell cycle, although whether this is adaptive, or incidental to other events in the cell, such as chromatin condensation, we do not know.

  1. CycleBase.org - a comprehensive multi-organism online database of cell-cycle experiments

    DEFF Research Database (Denmark)

    Gauthier, Nicholas Paul; Larsen, Malene Erup; Wernersson, Rasmus;

    2007-01-01

    The past decade has seen the publication of a large number of cell-cycle microarray studies and many more are in the pipeline. However, data from these experiments are not easy to access, combine and evaluate. We have developed a centralized database with an easy-to-use interface, Cyclebase.......org, for viewing and downloading these data. The user interface facilitates searches for genes of interest as well as downloads of genome-wide results. Individual genes are displayed with graphs of expression profiles throughout the cell cycle from all available experiments. These expression profiles are...

  2. Global guidance on environmental life cycle impact assessment indicators: Progress and case study

    DEFF Research Database (Denmark)

    Frischknecht, Rolf; Fantke, Peter; Tschümperlin, Laura;

    2016-01-01

    Purpose The life cycle impact assessment (LCIA) guidance flagship project of the United Nations Environment Programme (UNEP)/Society of Environmental Toxicology and Chemistry (SETAC) Life Cycle Initiative aims at providing global guidance and building scientific consensus on environmental LCIA...... warming, fine particulate matter emissions, water use and land use, plus cross-cutting issues and LCAbased footprints. The paper reports the process and progress and specific results obtained in the different task forces (TFs). Additionally, a rice LCA case study common to all TF has been developed. Three...... practicality of the finally recommended impact category indicators. Results and discussion The global warming TF concludes that analysts should explore the sensitivity of LCA results to metrics other than GWP. The particulate matter TF attained initial guidance of how to include health effects from PM2...

  3. International Project on Innovative Nuclear Reactors and Fuel Cycles (INPRO). 2008 progress report

    International Nuclear Information System (INIS)

    The purpose of the work is to review the progress of the IAEA international project for innovative reactors and fuel cycle technologies (INPRO). The publication reports about the recognition of INPRO and on general Information on INPRO, its strengths, memberships, collaboration with other international initiatives, the INPRO organization and management and the history of INPRO. The section on the progress of INPRO in 2008 contains task 1: INPRO Methodology, task 2: Assessment Studies, task 3: Nuclear Energy Visions for the 21st Century, task 4: Infrastructure and Institutional Innovation, task 5: Common User Considerations and task 6: Collaborative Projects. Conclusions and New Trends are followed by a bibliography. Annex I deals with the INPRO project management in 2008 and Annex II provides a selection of photographs from 2008. Finally a list of acronyms is provided

  4. Patterns of cell division revealed by transcriptional regulation of genes during the cell cycle in plants.

    OpenAIRE

    Fobert, P R; Coen, E S; Murphy, G. J.; Doonan, J H

    1994-01-01

    Transcripts from five cell cycle related genes accumulate in isolated cells dispersed throughout the actively dividing regions of plant meristems. We propose that this pattern reflects gene expression during particular phases of the cell division cycle. The high proportion of isolated cells suggests that synchrony between daughter cells is rapidly lost following mitosis. This is the first time that such a cell specific expression pattern has been described in a higher organism. Counterstainin...

  5. Cell cycle sibling rivalry: Cdc2 vs. Cdk2.

    Science.gov (United States)

    Kaldis, Philipp; Aleem, Eiman

    2005-11-01

    It has been long believed that the cyclin-dependent kinase 2 (Cdk2) binds to cyclin E or cyclin A and exclusively promotes the G1/S phase transition and that Cdc2/cyclin B complexes play a major role in mitosis. We now provide evidence that Cdc2 binds to cyclin E (in addition to cyclin A and B) and is able to promote the G1/S transition. This new concept indicates that both Cdk2 and/or Cdc2 can drive cells through G1/S phase in parallel. In this review we discuss the classic cell cycle model and how results from knockout mice provide new evidence that refute this model. We focus on the roles of Cdc2 and p27 in regulating the mammalian cell cycle and propose a new model for cell cycle regulation that accommodates these novel findings. PMID:16258277

  6. Hedyotis diffusa Willd extract inhibits HT-29 cell proliferation via cell cycle arrest.

    Science.gov (United States)

    Lin, Minghe; Lin, Jiumao; Wei, Lihui; Xu, Wei; Hong, Zhenfeng; Cai, Qiaoyan; Peng, Jun; Zhu, Dezeng

    2012-08-01

    Hedyotis diffusa Willd (HDW) has long been used as an important component in several Chinese medicine formulae to clinically treat various types of cancer, including colorectal cancer (CRC). Previously, we reported that HDW inhibits CRC growth via the induction of cancer cell apoptosis and the inhibition of tumor angiogenesis. In the present study, to further elucidate the mechanism of HDW-mediated antitumor activity, we investigated the effect of HDW ethanol extract (EEHDW) on the proliferation of HT-29 human colon carcinoma cells. We found that EEHDW reduced HT-29 cell viability and survival in a dose- and time-dependent manner. We also observed that EEHDW treatment blocked the cell cycle, preventing G1 to S progression, and reduced mRNA expression of pro-proliferative PCNA, Cyclin D1 and CDK4, but increased that of anti-proliferative p21. Our findings suggest that Hedyotis diffusa Willd may be an effective treatment for CRC via the suppression of cancer cell proliferation. PMID:23139718

  7. Time course of morphine’s effects on adult hippocampal subgranular zone reveals preferential inhibition of cells in S phase of the cell cycle and a subpopulation of immature neurons

    OpenAIRE

    Arguello, Amy A.; Harburg, Gwyndolen C.; Schonborn, Joshua R.; Mandyam, Chitra D.; Yamaguchi, Masahiro; Eisch, Amelia J.

    2008-01-01

    Opiates, such as morphine, decrease neurogenesis in the adult hippocampal subgranular zone (SGZ), raising the possibility that decreased neurogenesis contributes to opiate-induced cognitive deficits. However, there is an incomplete understanding of how alterations in cell cycle progression and progenitor maturation contribute to this decrease. The present study examined how morphine regulates progenitor cell cycle, cell death and immature SGZ neurons (Experiment 1) as well as the progression ...

  8. Time course of morphine's effects on adult hippocampal subgranular zone reveals preferential inhibition of cells in S phase of the cell cycle and a subpopulation of immature neurons.

    Science.gov (United States)

    Arguello, A A; Harburg, G C; Schonborn, J R; Mandyam, C D; Yamaguchi, M; Eisch, A J

    2008-11-11

    Opiates, such as morphine, decrease neurogenesis in the adult hippocampal subgranular zone (SGZ), raising the possibility that decreased neurogenesis contributes to opiate-induced cognitive deficits. However, there is an incomplete understanding of how alterations in cell cycle progression and progenitor maturation contribute to this decrease. The present study examined how morphine regulates progenitor cell cycle, cell death and immature SGZ neurons (experiment 1) as well as the progression of SGZ progenitors through key stages of maturation (experiment 2). In experiment 1, mice received sham or morphine pellets (s.c., 0 and 48 h) and bromodeoxyuridine (BrdU) 2 h prior to sacrifice (24, 72 or 96 h). Morphine decreased both the number of S phase and total cycling cells, as there were fewer cells immunoreactive (IR) for the S phase marker BrdU and the cell cycle marker Ki67. The percentage of Ki67-IR cells that were BrdU-IR was decreased after 24 but not 96 h of morphine, suggesting a disproportionate effect on S phase cells relative to all cycling cells at this time point. Cell death (activated caspase-3 counts) was increased after 24 but not 96 h. In experiment 2, nestin-green fluorescent protein (GFP) mice given BrdU 1 day prior to morphine or sham surgery (0 and 48 h, sacrifice 96 h) had fewer Ki67-IR cells, but no change in BrdU-IR cell number, suggesting that this population of BrdU-IR cells was less sensitive to morphine. Interestingly, examination of key stages of progenitor cell maturation revealed that morphine increased the percent of BrdU-IR cells that were type 2b and decreased the percent that were immature neurons. These data suggest that chronic morphine decreases SGZ neurogenesis by inhibiting dividing cells, particularly those in S phase, and progenitor cell progression to a more mature neuronal stage. PMID:18832014

  9. Progress in focus: recent advances in histochemistry and cell biology.

    Science.gov (United States)

    Asan, Esther

    2002-12-01

    Advances in histochemical and cell biological techniques enable increasingly refined investigations into the cellular and subcellular distribution of specific molecules and into their role in dynamic processes; thus progress in these fields complements the growing knowledge in genomics and proteomics. The present review summarizes recent technical progress and novel applications. PMID:12483316

  10. Coordinated progression through two subtranscriptomes underlies the tachyzoite cycle of Toxoplasma gondii.

    Directory of Open Access Journals (Sweden)

    Michael S Behnke

    Full Text Available BACKGROUND: Apicomplexan parasites replicate by varied and unusual processes where the typically eukaryotic expansion of cellular components and chromosome cycle are coordinated with the biosynthesis of parasite-specific structures essential for transmission. METHODOLOGY/PRINCIPAL FINDINGS: Here we describe the global cell cycle transcriptome of the tachyzoite stage of Toxoplasma gondii. In dividing tachyzoites, more than a third of the mRNAs exhibit significant cyclical profiles whose timing correlates with biosynthetic events that unfold during daughter parasite formation. These 2,833 mRNAs have a bimodal organization with peak expression occurring in one of two transcriptional waves that are bounded by the transition into S phase and cell cycle exit following cytokinesis. The G1-subtranscriptome is enriched for genes required for basal biosynthetic and metabolic functions, similar to most eukaryotes, while the S/M-subtranscriptome is characterized by the uniquely apicomplexan requirements of parasite maturation, development of specialized organelles, and egress of infectious daughter cells. Two dozen AP2 transcription factors form a series through the tachyzoite cycle with successive sharp peaks of protein expression in the same timeframes as their mRNA patterns, indicating that the mechanisms responsible for the timing of protein delivery might be mediated by AP2 domains with different promoter recognition specificities. CONCLUSION/SIGNIFICANCE: Underlying each of the major events in apicomplexan cell cycles, and many more subordinate actions, are dynamic changes in parasite gene expression. The mechanisms responsible for cyclical gene expression timing are likely crucial to the efficiency of parasite replication and may provide new avenues for interfering with parasite growth.

  11. DNA-damage response network at the crossroads of cell-cycle checkpoints,cellular senescence and apoptosis

    Institute of Scientific and Technical Information of China (English)

    SCHMITT Estelle; PAQUET Claudie; BEAUCHEMIN Myriam; BERTRAND Richard

    2007-01-01

    Tissue homeostasis requires a carefully-orchestrated balance between cell proliferation,cellular senescence and cell death.Cells proliferate through a cell cycle that is tightly regulated by cyclin-dependent kinase activities.Cellular senescence is a safeguard program limiting the proliferative competence of cells in living organisms.Apoptosis eliminates unwanted cells by the coordinated activity of gene products that regulate and effect cell death.The intimate link between the cell cycle,cellular senescence,apoptosis regulation,cancer development and tumor responses to cancer treatment has become eminently apparent.Extensive research on tumor suppressor genes,oncogenes,the cell cycle and apoptosis regulatory genes has revealed how the DNA damage-sensing and -signaling pathways,referred to as the DNA-damage response network,are tied to cell proliferation,cell-cycle arrest,cellular senescence and apoptosis.DNA-damage responses are complex,involving "sensor" proteins that sense the damage,and transmit signals to "transducer" proteins,which,in turn,convey the signals to numerous "effector" proteins implicated in specific cellular pathways,including DNA repair mechanisms,cell-cycle checkpoints,cellular senescence and apoptosis.The Bcl-2 family of proteins stands among the most crucial regulators of apoptosis and performs vital functions in deciding whether a cell will live or die after cancer chemotherapy and irradiation.In addition,several studies have now revealed that members of the Bcl-2 family also interface with the cell cycle,DNA repair/recombination and cellular senescence,effects that are generally distinct from their function in apoptosis.In this review,we report progress in understanding the molecular networks that regulate cell-cycle checkpoints,cellular senescence and apoptosis after DNA damage,and discuss the influence of some Bcl-2 family members on cell-cycle checkpoint regulation.

  12. MiR-107 and MiR-185 can induce cell cycle arrest in human non small cell lung cancer cell lines.

    Directory of Open Access Journals (Sweden)

    Yukari Takahashi

    Full Text Available BACKGROUND: MicroRNAs (miRNAs are short single stranded noncoding RNAs that suppress gene expression through either translational repression or degradation of target mRNAs. The annealing between messenger RNAs and 5' seed region of miRNAs is believed to be essential for the specific suppression of target gene expression. One miRNA can have several hundred different targets in a cell. Rapidly accumulating evidence suggests that many miRNAs are involved in cell cycle regulation and consequentially play critical roles in carcinogenesis. METHODOLOGY/PRINCIPAL FINDINGS: Introduction of synthetic miR-107 or miR-185 suppressed growth of the human non-small cell lung cancer cell lines. Flow cytometry analysis revealed these miRNAs induce a G1 cell cycle arrest in H1299 cells and the suppression of cell cycle progression is stronger than that by Let-7 miRNA. By the gene expression analyses with oligonucleotide microarrays, we find hundreds of genes are affected by transfection of these miRNAs. Using miRNA-target prediction analyses and the array data, we listed up a set of likely targets of miR-107 and miR-185 for G1 cell cycle arrest and validate a subset of them using real-time RT-PCR and immunoblotting for CDK6. CONCLUSIONS/SIGNIFICANCE: We identified new cell cycle regulating miRNAs, miR-107 and miR-185, localized in frequently altered chromosomal regions in human lung cancers. Especially for miR-107, a large number of down-regulated genes are annotated with the gene ontology term 'cell cycle'. Our results suggest that these miRNAs may contribute to regulate cell cycle in human malignant tumors.

  13. 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.

  14. Entrainability of cell cycle oscillator models with exponential growth of cell mass.

    Science.gov (United States)

    Nakao, Mitsuyuki; Enkhkhudulmur, Tsog-Erdene; Katayama, Norihiro; Karashima, Akihiro

    2014-01-01

    Among various aspects of cell cycle, understanding synchronization mechanism of cell cycle is important because of the following reasons. (1)Cycles of cell assembly should synchronize to form an organ. (2) Synchronizing cell cycles are required to experimental analysis of regulatory mechanisms of cell cycles. (3) Cell cycle has a distinct phase relationship with the other biological rhythms such as circadian rhythm. However, forced as well as mutual entrainment mechanisms are not clearly known. In this study, we investigated entrainability of cell cycle models of yeast cell under the periodic forcing to both of the cell mass and molecular dynamics. Dynamics of models under study involve the cell mass growing exponentially. In our result, they are shown to allow only a limited frequency range for being entrained by the periodic forcing. In contrast, models with linear growth are shown to be entrained in a wider frequency range. It is concluded that if the cell mass is included in the cell cycle regulation, its entrainability is sensitive to a shape of growth curve assumed in the model. PMID:25571564

  15. Periodic synthesis of phospholipids during the Caulobacter crescentus cell cycle.

    OpenAIRE

    O'Neill, E A; Bender, R A

    1987-01-01

    Net phospholipid synthesis is discontinuous during the Caulobacter crescentus cell cycle with synthesis restricted to two discrete periods. The first period of net phospholipid synthesis begins in the swarmer cell shortly after cell division and ends at about the time when DNA replication initiates. The second period of phospholipid synthesis begins at a time when DNA replication is about two-thirds complete and ends at about the same time that DNA replication terminates. Thus, considerable D...

  16. Increased SHP-1 expression results in radioresistance, inhibition of cellular senescence, and cell cycle redistribution in nasopharyngeal carcinoma cells

    International Nuclear Information System (INIS)

    Radioresistance is the main limit to the efficacy of radiotherapy in nasopharyngeal carcinoma (NPC). SHP-1 is involved in cancer progression, but its role in radioresistance and senescence of NPC is not well understood. This study aimed to assess the role of SHP-1 in the radioresistance and senescence of NPC cells. SHP-1 was knocked-down and overexpressed in CNE-1 and CNE-2 cells using lentiviruses. Cells were irradiated to observe their radiosensitivity by colony forming assay. BrdU incorporation assay and flow cytometry were used to monitor cell cycle. A β-galactosidase assay was used to assess senescence. Western blot was used to assess SHP-1, p21, p53, pRb, Rb, H3K9Me3, HP1γ, CDK4, cyclin D1, cyclin E, and p16 protein expressions. Compared with CNE-1-scramble shRNA cells, SHP-1 downregulation resulted in increased senescence (+107 %, P < 0.001), increased radiosensitivity, higher proportion of cells in G0/G1 (+33 %, P < 0.001), decreased expressions of CDK4 (−44 %, P < 0.001), cyclin D1 (−41 %, P = 0.001), cyclin E (−97 %, P < 0.001), Rb (−79 %, P < 0.001), and pRb (−76 %, P = 0.001), and increased expression of p16 (+120 %, P = 0.02). Furthermore, SHP-1 overexpression resulted in radioresistance, inhibition of cellular senescence, and cell cycle arrest in the S phase. Levels of p53 and p21 were unchanged in both cell lines (all P > 0.05). SHP-1 has a critical role in radioresistance, cell cycle progression, and senescence of NPC cells. Down-regulating SHP-1 may be a promising therapeutic approach for treating patients with NPC

  17. 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.

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

    International Nuclear Information System (INIS)

    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 γ -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, p34cdc2 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

  19. Toxicity of drinking water disinfection byproducts: cell cycle alterations induced by the monohaloacetonitriles.

    Science.gov (United States)

    Komaki, Yukako; Mariñas, Benito J; Plewa, Michael J

    2014-10-01

    Haloacetonitriles (HANs) are a chemical class of drinking water disinfection byproducts (DBPs) that form from reactions between disinfectants and nitrogen-containing precursors, the latter more prevalent in water sources impacted by algae bloom and municipal wastewater effluent discharge. HANs, previously demonstrated to be genotoxic, were investigated for their effects on the mammalian cell cycle. Treating Chinese hamster ovary (CHO) cells with monoHANs followed by the release from the chemical treatment resulted in the accumulation of abnormally high DNA content in cells over time (hyperploid). The potency for the cell cycle alteration followed the order: iodoacetonitrile (IAN) > bromoacetonitrile (BAN) ≫ chloroacetonitrile (CAN). Exposure to 6 μM IAN, 12 μM BAN and 900 μM CAN after 26 h post-treatment incubation resulted in DNA repair; however, subsequent cell cycle alteration effects were observed. Cell proliferation of HAN-treated cells was suppressed for as long as 43 to 52 h. Enlarged cell size was observed after 52 h post-treatment incubation without the induction of cytotoxicity. The HAN-mediated cell cycle alteration was mitosis- and proliferation-dependent, which suggests that HAN treatment induced mitosis override, and that HAN-treated cells proceeded into S phase and directly into the next cell cycle. Cells with multiples genomes would result in aneuploidy (state of abnormal chromosome number and DNA content) at the next mitosis since extra centrosomes could compromise the assembly of bipolar spindles. There is accumulating evidence of a transient tetraploid state proceeding to aneuploidy in cancer progression. Biological self-defense systems to ensure genomic stability and to eliminate tetraploid cells exist in eukaryotic cells. A key tumor suppressor gene, p53, is oftentimes mutated in various types of human cancer. It is possible that HAN disruption of the normal cell cycle and the generation of aberrant cells with an abnormal number of

  20. Cytotoxicity and cell cycle effects of novel indolo[2,3-b]quinoline derivatives.

    Science.gov (United States)

    Humeniuk, Rita; Kaczmarek, Lukasz; Peczyńska-Czoch, Wanda; Marcinkowska, Ewa

    2003-01-01

    Cellular effects of novel indolo[2,3-b]quinoline derivatives were studied. These compounds are synthetic analogs of plant alkaloid neocryptolepine (5-methyl-5H-indolo[2,3-b]quinoline) present in extracts from Cryptolepis sanguinolenta. They are traditionally used in natural medicine in Central and West Africa. Previous molecular and computational studies indicated that these compounds were DNA intercalators and inhibitors of topoisomerase II. We have extended our studies on their mode of action to the cellular level. Past experiments have shown that these compounds were active in vitro against cell lines derived from solid tumors, so for the present studies we selected leukemic cell lines. Jurkat acute T cell, CCRF-CEM T lymphoblastoid, THP-1 acute monocytic, HL-60 acute promyelocytic leukemias, and HL-60/MX2 subline with reduced expression of topoisomerase II were used. We evaluated the cytotoxicity and cell cycle effects of the indolo[2,3-b]quinoline compounds. We also tested if these compounds were able to induce apoptosis in the cells. Our studies revealed that novel indolo[2,3-b]quinoline derivatives were more cytotoxic to all cell lines than etoposide (used as a reference topoisomerase II inhibitor), and that their cytotoxicity depended on the substituents introduced to the indolo[2,3-b]quinoline core. Surprisingly, our studies have shown that HL-60/MX2 cell line and also THP-1 cell line, resistant to etoposide, were susceptible to methyl- and methoxy-substituted indolo[2,3-b]quinoline derivatives. In parallel to the evaluation of cytotoxicity we studied cell cycle effects of these compounds. Treatment of HL-60 cells with etoposide in subcytotoxic concentrations resulted in a massive accumulation of the cells in the G2/M phase of the cell cycle. When we used subcytotoxic concentrations of our novel indolo[2,3-b]quinoline derivatives the cell cycle progression of HL-60 cells was not affected. Moreover, the cell cycle of HL-60/MX2 cells was not influenced by

  1. Thermal stress cycling of GaAs solar cells

    Science.gov (United States)

    Janousek, B. K.; Francis, R. W.; Wendt, J. P.

    1985-01-01

    A thermal cycling experiment was performed on GaAs solar cells to establish the electrical and structural integrity of these cells under the temperature conditions of a simulated low-Earth orbit of 3-year duration. Thirty single junction GaAs cells were obtained and tests were performed to establish the beginning-of-life characteristics of these cells. The tests consisted of cell I-V power output curves, from which were obtained short-circuit current, open circuit voltage, fill factor, and cell efficiency, and optical micrographs, spectral response, and ion microprobe mass analysis (IMMA) depth profiles on both the front surfaces and the front metallic contacts of the cells. Following 5,000 thermal cycles, the performance of the cells was reexamined in addition to any factors which might contribute to performance degradation. It is established that, after 5,000 thermal cycles, the cells retain their power output with no loss of structural integrity or change in physical appearance.

  2. Labeling of lectin receptors during the cell cycle.

    Science.gov (United States)

    Garrido, J

    1976-12-01

    Labeling of lectin receptors during the cell cycle. (Localizabión de receptores para lectinas durante el ciclo celular). Arch. Biol. Med. Exper. 10: 100-104, 1976. The topographic distribution of specific cell surface receptors for concanavalin A and wheat germ agglutinin was studied by ultrastructural labeling in the course of the cell cycle. C12TSV5 cells were synchronized by double thymidine block or mechanical selection (shakeoff). They were labeled by means of lectin-peroxidase techniques while in G1 S, G2 and M phases of the cycle. The results obtained were similar for both lectins employed. Interphase cells (G1 S, G2) present a stlihtly discontinous labeling pattern that is similar to the one observed on unsynchronized cells of the same line. Cells in mitosis, on the contrary, present a highly discontinous distribution of reaction product. This pattern disappears after the cells enters G1 and is not present on mitotic cells fixed in aldehyde prior to labeling. PMID:1030938

  3. Comparative study of the antitumor effect of natural monoterpenes: relationship to cell cycle analysis

    Directory of Open Access Journals (Sweden)

    Abdeslam Jaafari

    2012-06-01

    Full Text Available Monoterpenes have been identified as responsible of important therapeutic effects of plant-extracts. In this work, we try to compare the cytotoxic effect of six monoterpenes (carvacrol, thymol, carveol, carvone, eugenol and isopulegol as well as their molecular mechanisms. The in vitro antitumor activity of the tested products, evaluated against five tumor cell lines, show that the carvacrol is the most cytotoxic monoterpene. The investigation of an eventual synergistic effect of the six natural monoterpenes with two anticancer drugs revealed that there is a significant synergy between them (p<5%. On the other hand, the effect of the tested products on cell cycle progression was examined by flow cytometry after DNA staining in order to investigate the molecular mechanism of their cytotoxic activity. The results revealed that carvacrol and carveol stopped the cell cycle progression in S phase; however, thymol and isopulegol stopped it in G0/G1 phase. Regarding carvone and eugenol, no effect on cell cycle was observed.

  4. TGF-β Signaling Regulates Pancreatic β-Cell Proliferation through Control of Cell Cycle Regulator p27 Expression

    International Nuclear Information System (INIS)

    Proliferation of pancreatic β-cells is an important mechanism underlying β-cell mass adaptation to metabolic demands. Increasing β-cell mass by regeneration may ameliorate or correct both type 1 and type 2 diabetes, which both result from inadequate production of insulin by β-cells of the pancreatic islet. Transforming growth factor β (TGF-β) signaling is essential for fetal development and growth of pancreatic islets. In this study, we exposed HIT-T15, a clonal pancreatic β-cell line, to TGF-β signaling. We found that inhibition of TGF-β signaling promotes proliferation of the cells significantly, while TGF-β signaling stimulation inhibits proliferation of the cells remarkably. We confirmed that this proliferative regulation by TGF-β signaling is due to the changed expression of the cell cycle regulator p27. Furthermore, we demonstrated that there is no observed effect on transcriptional activity of p27 by TGF-β signaling. Our data show that TGF-β signaling mediates the cell-cycle progression of pancreatic β-cells by regulating the nuclear localization of CDK inhibitor, p27. Inhibition of TGF-β signaling reduces the nuclear accumulation of p27, and as a result this inhibition promotes proliferation of β-cells

  5. Cell Cycle Abnormality in Metabolic Syndrome and Nuclear Receptors as an Emerging Therapeutic Target

    Directory of Open Access Journals (Sweden)

    Nakatsuka,Atsuko

    2013-06-01

    Full Text Available In recent years, many researchers have emphasized the importance of metabolic syndrome based on its increasing prevalence and its adverse prognosis due to associated chronic vascular complications. Upstream of a cluster of metabolic and vascular disorders is the accumulation of visceral adipose tissue, which plays a central role in the pathophysiology. In the accumulation of adipose tissues, cell cycle regulation is tightly linked to cellular processes such as proliferation, hypertrophy and apoptosis. In addition, various cell cycle abnormalities have also been observed in other tissues, such as kidneys and the cardiovascular system, and they are critically involved in the progression of disease. Here, we discuss cell cycle abnormalities in metabolic syndrome in various tissues. Furthermore, we describe the role of nuclear receptors in cell growth and survival, and glucose and lipid metabolism in the whole body. Therapeutic strategies for modulating various cell cycles in metabolic disorders by targeting nuclear receptors may overcome obesity and its chronic vascular complications in the future.

  6. 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

  7. High efficiency fuel cell/advanced turbine power cycles

    Energy Technology Data Exchange (ETDEWEB)

    Morehead, H. [Westinghouse Electric Corp., Orlando, FL (United States)

    1995-10-19

    An outline of the Westinghouse high-efficiency fuel cell/advanced turbine power cycle is presented. The following topics are discussed: The Westinghouse SOFC pilot manufacturing facility, cell scale-up plan, pressure effects on SOFC power and efficiency, sureCell versus conventional gas turbine plants, sureCell product line for distributed power applications, 20 MW pressurized-SOFC/gas turbine power plant, 10 MW SOFC/CT power plant, sureCell plant concept design requirements, and Westinghouse SOFC market entry.

  8. 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...... 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...

  9. Sulforaphane induces cell cycle arrest by protecting RB-E2F-1 complex in epithelial ovarian cancer cells

    Directory of Open Access Journals (Sweden)

    Morris Robert

    2010-03-01

    Full Text Available Abstract Background Sulforaphane (SFN, an isothiocyanate phytochemical present predominantly in cruciferous vegetables such as brussels sprout and broccoli, is considered a promising chemo-preventive agent against cancer. In-vitro exposure to SFN appears to result in the induction of apoptosis and cell-cycle arrest in a variety of tumor types. However, the molecular mechanisms leading to the inhibition of cell cycle progression by SFN are poorly understood in epithelial ovarian cancer cells (EOC. The aim of this study is to understand the signaling mechanisms through which SFN influences the cell growth and proliferation in EOC. Results SFN at concentrations of 5 - 20 μM induced a dose-dependent suppression of growth in cell lines MDAH 2774 and SkOV-3 with an IC50 of ~8 μM after a 3 day exposure. Combination treatment with chemotherapeutic agent, paclitaxel, resulted in additive growth suppression. SFN at ~8 μM decreased growth by 40% and 20% on day 1 in MDAH 2774 and SkOV-3, respectively. Cells treated with cytotoxic concentrations of SFN have reduced cell migration and increased apoptotic cell death via an increase in Bak/Bcl-2 ratio and cleavage of procaspase-9 and poly (ADP-ribose-polymerase (PARP. Gene expression profile analysis of cell cycle regulated proteins demonstrated increased levels of tumor suppressor retinoblastoma protein (RB and decreased levels of E2F-1 transcription factor. SFN treatment resulted in G1 cell cycle arrest through down modulation of RB phosphorylation and by protecting the RB-E2F-1 complex. Conclusions SFN induces growth arrest and apoptosis in EOC cells. Inhibition of retinoblastoma (RB phosphorylation and reduction in levels of free E2F-1 appear to play an important role in EOC growth arrest.

  10. Polycomb group proteins in cell cycle progression and cancer

    DEFF Research Database (Denmark)

    Pasini, Diego; Bracken, Adrian P; Helin, Kristian

    2004-01-01

    Epigenetic deregulation of gene expression is emerging as key mechanism in tumorigenesis. Deregulated activity of the chromatin remodeling Polycomb Repressive Complex 2 (PRC2) has recently been shown to be a frequent event in human tumors. Here we discuss these findings and speculate on the role ...

  11. Influence of chlorine dioxide on cell death and cell cycle of human gingival fibroblasts

    OpenAIRE

    Nishikiori, Ryo; Nomura, Yuji; Sawajiri, Masahiko; Masuki, Kohei; Hirata, Isao; Okazaki, Masayuki

    2008-01-01

    Objectives: The effects of chlorine dioxide (ClO2), sodium hypochlorite (NaOCl), and hydrogen peroxide (H2O2) on cell death and the cell cycle of human gingival fibroblast (HGF) cells were examined. Methods: The inhibition of HGF cell growth was evaluated using a Cell Counting Kit-8. The cell cycle was assessed with propidium iodide-stained cells (distribution of cells in G0/G1, S, G2/M phases) using flow cytometry. The patterns of cell death (necrosis and apoptosis) were analyzed using f...

  12. Targeting TRPM2 Channels Impairs Radiation-Induced Cell Cycle Arrest and Fosters Cell Death of T Cell Leukemia Cells in a Bcl-2-Dependent Manner

    Directory of Open Access Journals (Sweden)

    Dominik Klumpp

    2016-01-01

    Full Text Available Messenger RNA data of lymphohematopoietic cancer lines suggest a correlation between expression of the cation channel TRPM2 and the antiapoptotic protein Bcl-2. The latter is overexpressed in various tumor entities and mediates therapy resistance. Here, we analyzed the crosstalk between Bcl-2 and TRPM2 channels in T cell leukemia cells during oxidative stress as conferred by ionizing radiation (IR. To this end, the effects of TRPM2 inhibition or knock-down on plasma membrane currents, Ca2+ signaling, mitochondrial superoxide anion formation, and cell cycle progression were compared between irradiated (0–10 Gy Bcl-2-overexpressing and empty vector-transfected Jurkat cells. As a result, IR stimulated a TRPM2-mediated Ca2+-entry, which was higher in Bcl-2-overexpressing than in control cells and which contributed to IR-induced G2/M cell cycle arrest. TRPM2 inhibition induced a release from G2/M arrest resulting in cell death. Collectively, this data suggests a pivotal function of TRPM2 in the DNA damage response of T cell leukemia cells. Apoptosis-resistant Bcl-2-overexpressing cells even can afford higher TRPM2 activity without risking a hazardous Ca2+-overload-induced mitochondrial superoxide anion formation.

  13. Recent progress on microcrystalline solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Shah, A.; Meier, J.; Torres, P.; Kroll, U.; Fischer, D.; Beck, N.; Wyrsch, N.; Keppner, H. [Univ. of Neuchatel (Switzerland). Inst. of Microtechnology

    1997-12-31

    The most important features of microcrystalline silicon ({micro}c-Si:H) and microcrystalline silicon based p-i-n solar cells (specially those deposited by VHF-Glow Discharge) are reviewed. Since such material has been recognized to be a photovoltaically active material, stabilized cell efficiencies have steadily risen and have now reached 12% in the so called micromorph (microcrystalline/amorphous) tandem cell configuration.

  14. Progress in quantum well solar cells

    International Nuclear Information System (INIS)

    A quantum well solar cell is a special multiple-band gap device with intermediate properties between heterojunction cells (sum of the currents generated in the different materials but voltage controlled by the lowest of the two band gaps) and tandem cells (sum of the voltages but current determined by the worst of the two sub-cells). Strain-balanced GaAsP/InGaAs multi-quantum wells move the absorption edge of GaAs solar cells closer to the optimum value for single junction cells with no need for any partially relaxed buffer layer to accommodate lattice mismatch between the absorbing layers and the substrate. Covering a large spectral range in a single-junction cell has the benefit that the cell remains close to optimal efficiency in the varying spectral conditions of a typical terrestrial concentrator. Though monolithic multi-junction cells have significantly higher efficiency, the series-current constraint means that some of this advantage is lost as the illuminating spectra and the cell temperature change from the values at which the tandem was optimised. The good material quality which can be achieved with these structures makes the cell dark current at the typical operating conditions expected under moderate sunlight concentration (∼200x), increasingly dominated by radiative processes the deeper the quantum wells. We will report on high concentration measurements of strain-balanced quantum well solar cells with and without Bragg-stack reflectors and discuss the 'additivity' between the short-circuit current and the dark-current. We discuss a 50 shallow well cell with measured AM1.5d efficiency of (26 ± 1)% at around 200x concentration. This is approximately 2% higher than a comparable p-n cell with comparable material quality. The good material quality is also responsible for another effect previously observed in single quantum wells becoming measurable in structures with 5 and 10 wells, that is the suppression of carrier recombination in quantum wells with

  15. Sapodilla plum (Achras sapota) induces apoptosis in cancer cell lines and inhibits tumor progression in mice.

    Science.gov (United States)

    Srivastava, Mrinal; Hegde, Mahesh; Chiruvella, Kishore K; Koroth, Jinsha; Bhattacharya, Souvari; Choudhary, Bibha; Raghavan, Sathees C

    2014-01-01

    Intake of fruits rich in antioxidants in daily diet is suggested to be cancer preventive. Sapota is a tropical fruit grown and consumed extensively in several countries including India and Mexico. Here we show that methanolic extracts of Sapota fruit (MESF) induces cytotoxicity in a dose-dependent manner in cancer cell lines. Cell cycle analysis suggested activation of apoptosis, without arresting cell cycle progression. Annexin V-propidium iodide double-staining demonstrated that Sapota fruit extracts potentiate apoptosis rather than necrosis in cancer cells. Loss of mitochondrial membrane potential, upregulation of proapoptotic proteins, activation of MCL-1, PARP-1, and Caspase 9 suggest that MESF treatment leads to activation of mitochondrial pathway of apoptosis. More importantly, we show that MESF treatment leads to significant inhibition of tumor growth and a 3-fold increase in the life span of tumor bearing animals compared to untreated tumor mice. PMID:25142835

  16. Wnt7b is an important intrinsic regulator of hair follicle stem cell homeostasis and hair follicle cycling

    OpenAIRE

    Kandyba, Eve; Kobielak, Krzysztof

    2014-01-01

    The hair follicle (HF) is an exceptional mini-organ to study the mechanisms which regulate HF morphogenesis, cycling, hair follicle stem cell (hfSCs) homeostasis and progeny differentiation. During morphogenesis, Wnt signaling is well characterized in the initiation of HF patterning but less is known about which particular Wnt ligands are required and whether individual Wnt ligands act in an indispensable or redundant manner during postnatal hfSCs anagen onset and HF cycle progression. Previo...

  17. Characterization and Evolution of the Cell Cycle-Associated Mob Domain-Containing Proteins in Eukaryotes

    Directory of Open Access Journals (Sweden)

    Nicola Vitulo

    2007-01-01

    Full Text Available The MOB family includes a group of cell cycle-associated proteins highly conserved throughout eukaryotes, whose founding members are implicated in mitotic exit and co-ordination of cell cycle progression with cell polarity and morphogenesis. Here we report the characterization and evolution of the MOB domain-containing proteins as inferred from the 43 eukaryotic genomes so far sequenced. We show that genes for Mob-like proteins are present in at least 41 of these genomes, confi rming the universal distribution of this protein family and suggesting its prominent biological function. The phylogenetic analysis reveals fi ve distinct MOB domain classes, showing a progressive expansion of this family from unicellular to multicellular organisms, reaching the highest number in mammals. Plant Mob genes appear to have evolved from a single ancestor, most likely after the loss of one or more genes during the early stage of Viridiplantae evolutionary history. Three of the Mob classes are widespread among most of the analyzed organisms. The possible biological and molecular function of Mob proteins and their role in conserved signaling pathways related to cell proliferation, cell death and cell polarity are also presented and critically discussed.

  18. Biogenesis and dynamics of mitochondria during the cell cycle: significance of 3'UTRs.

    Directory of Open Access Journals (Sweden)

    Marta Martínez-Diez

    Full Text Available Nowadays, we are facing a renaissance of mitochondria in cancer biology. However, our knowledge of the basic cell biology and on the timing and mechanisms that control the biosynthesis of mitochondrial constituents during progression through the cell cycle of mammalian cells remain largely unknown. Herein, we document the in vivo changes on mitochondrial morphology and dynamics that accompany cellular mitosis, and illustrate the following key points of the biogenesis of mitochondria during progression of liver cells through the cycle: (i the replication of nuclear and mitochondrial genomes is synchronized during cellular proliferation, (ii the accretion of OXPHOS proteins is asynchronously regulated during proliferation being the synthesis of beta-F1-ATPase and Hsp60 carried out also at G2/M and, (iii the biosynthesis of cardiolipin is achieved during the S phase, although full development of the mitochondrial membrane potential (DeltaPsim is attained at G2/M. Furthermore, we demonstrate using reporter constructs that the mechanism regulating the accretion of beta-F1-ATPase during cellular proliferation is controlled at the level of mRNA translation by the 3'UTR of the transcript. The 3'UTR-driven synthesis of the protein at G2/M is essential for conferring to the daughter cells the original phenotype of the parental cell. Our findings suggest that alterations on this process may promote deregulated beta-F1-ATPase expression in human cancer.

  19. Molecular cloning of a gene that is necessary for G1 progression in mammalian cells

    International Nuclear Information System (INIS)

    The authors have cloned a human cDNA that complements the mutation of ts11, a temperature-sensitive (ts) mutant of the BHK hamster cell line that at the nonpermissive temperature is blocked in progression through the G1 phase of the cell growth cycle. After transfecting human chromosomal DNA into ts11 cells and selecting for cells that had acquired a non-ts phenotype, the authors screened a geonomic library constructed in the EMBL3 λ vector from a secondary non-ts transformant and isolated a recombinant phage containing human DNA sequences that were uniformly present in primary and secondary non-ts transformants. Genomic probes that recognized an mRNA of about 2 kilobases in human cells were used to isolate from a cDNA expression library two cDNA plasmids that could efficiently transform ts11 cells to a non-ts phenotype. Sequencing of one of these cDNAs revealed a single open reading frame, which could encode a 540 amino acid protein. The ts11 gene has at least two other homologs in human DNA and thus it appears to be part of a small gene/pseudogene family. Experiments with serum-synchronized cells indicate that the expression of the ts11 gene, which is necessary for G1 progression, is itself cell-cycle regulated, being induced in approximately mid-G1

  20. MS4a4B, a CD20 homologue in T cells, inhibits T cell propagation by modulation of cell cycle.

    Directory of Open Access Journals (Sweden)

    Hui Xu

    Full Text Available MS4a4B, a CD20 homologue in T cells, is a novel member of the MS4A gene family in mice. The MS4A family includes CD20, FcεRIβ, HTm4 and at least 26 novel members that are characterized by their structural features: with four membrane-spanning domains, two extracellular domains and two cytoplasmic regions. CD20, FcεRIβ and HTm4 have been found to function in B cells, mast cells and hematopoietic cells respectively. However, little is known about the function of MS4a4B in T cell regulation. We demonstrate here that MS4a4B negatively regulates mouse T cell proliferation. MS4a4B is highly expressed in primary T cells, natural killer cells (NK and some T cell lines. But its expression in all malignant T cells, including thymoma and T hybridoma tested, was silenced. Interestingly, its expression was regulated during T cell activation. Viral vector-driven overexpression of MS4a4B in primary T cells and EL4 thymoma cells reduced cell proliferation. In contrast, knockdown of MS4a4B accelerated T cell proliferation. Cell cycle analysis showed that MS4a4B regulated T cell proliferation by inhibiting entry of the cells into S-G2/M phase. MS4a4B-mediated inhibition of cell cycle was correlated with upregulation of Cdk inhibitory proteins and decreased levels of Cdk2 activity, subsequently leading to inhibition of cell cycle progression. Our data indicate that MS4a4B negatively regulates T cell proliferation. MS4a4B, therefore, may serve as a modulator in the negative-feedback regulatory loop of activated T cells.

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

    DEFF Research Database (Denmark)

    de Lichtenberg, Ulrik; Jensen, Thomas Skøt; Brunak, Søren; Bork, Peer; Jensen, Lars Juhl

    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...... for assembling the same molecular machines just in time for action....

  2. Does Arabidopsis thaliana DREAM of cell cycle control?

    Science.gov (United States)

    Fischer, Martin; DeCaprio, James A

    2015-08-01

    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 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. PMID:26089020

  3. Onychin inhibits proliferation of vascular smooth muscle cells by regulating cell cycle

    Institute of Scientific and Technical Information of China (English)

    Ming YANG; Hong-lin HUANG; Bing-yang ZHU; Qin-hui TUO; Duan-fang LIAO

    2005-01-01

    Aim: To investigate the effects of onychin on the proliferation of cultured rat artery vascular smooth muscle cells (VSMCs) in the presence of 10% new-borncalf serum (NCS). Methods: Rat VSMCs were incubated with onychin 1-50 μmol/L or genistein 10 μmol/L in the presence of 10% NCS for 24 h. The proliferation of VSMCs was measured by cell counting and MTS/PMS colorimetric assays. Cell cycle progression was evaluated by flow cytometry. Retinoblastoma (Rb) phosphorylation, and expression of cyclin D1 and cyclin E were measured by Western blot assays. The tyrosine phosphorylation of ERK1/2 was examined by immunoprecipitation techniques using anti-phospho-tyrosine antibodies. Results: The proliferation of VSMCs was accelerated significantly in the presence of 10% NCS. Onychin reduced the metabolic rate of MTS and the cell number of VSMCs in the presence of 10% NCS in a dose-dependent manner. Flow cytometry analy sis revealed that the G1-phase fraction ratio in the onychin group was higher than that in the 10% NCS group (85.2% vs 70.0%, P<0.01), while the S-phase fraction ratio in the onychin group was lower than that in 10% NCS group (4.3% vs 16.4%, P<0.01). Western blot analysis showed that onychin inhibited Rb phos phorylation and reduced the expression of cyclin D1 and cyclin E. The effects of onychin on proliferation, the cell cycle and the expression of cyclins in VSMCs were similar to those of genistein, an inhibitor of tyrosine kinase. Furthermore immunoprecipitation studies showed that both onychin and genistein markedly inhibited the tyrosine phosphorylation of ERK1/2 induced by 10% NCS.Conclusion: Onychin inhibits the proliferation of VSMCs through G1 phase cell cycle arrest by decreasing the tyrosine phosphorylation of ERK1/2, and the expression of cyclin D1 and cyclin E, and sequentially inhibiting Rb phosphorylation.

  4. FDG-PET after two cycles of chemotherapy predicts treatment failure and progression-free survival in Hodgkin lymphoma

    DEFF Research Database (Denmark)

    Hutchings, Martin; Loft, Annika; Hansen, Mads;

    2005-01-01

    Risk-adapted lymphoma treatment requires early and accurate assessment of prognosis. This investigation prospectively assessed the value of positron emission tomography with 2-[18F]fluoro-2-deoxy-D-glucose (FDG-PET) after two cycles of chemotherapy for prediction of progression-free survival (PFS......) and overall survival (OS) in Hodgkin lymphoma (HL). Seventy-seven consecutive, newly diagnosed patients underwent FDG-PET at staging, after two and four cycles of chemotherapy, and after completion of chemotherapy. Median follow-up was 23 months. After two cycles of chemotherapy, 61 patients had...... negative FDG-PET scans and 16 patients had positive scans. Eleven of 16 FDG-PET-positive patients progressed and 2 died. Three of 61 FDG-PET-negative patients progressed; all were alive at latest follow-up. Survival analyses showed strong associations between early FDG-PET after two cycles and PFS (P...

  5. Hepatitis B virus X promotes HepG2 cell cycle progression and growth via downregulation expression of p16 protein%乙型肝炎病毒X蛋白抑制p16蛋白表达及其促进HepG2肝癌细胞生长

    Institute of Scientific and Technical Information of China (English)

    麦丽; 杨林; 邝建玉; 朱建芸; 康艳红; 张富程; 谢奇峰; 高志良

    2013-01-01

    Objective To investigate the effects and related mechanisms of hepatitis B virus X (HBx)protein on cell cycle and growth in hepatocellular carcinoma.Methods A human hepatocyte HepG2 cell line stably expressing a green fluorescent protein (GFP)-tagged HBx (HepG2/GFP-HBx cells) was used for the experiment,and HepG2 parental and HepG2/GFP cells was used as the controls.Effect of HBx on cell growth was evaluated by the MTT cell proliferation assay and on cell cycle progression by flow cytometry analysis of ceils with or without treatment with 5-aza-2'-deoxycytidine (5-Aza-CdR; 5 pmol/L).Effect of HBx expression on promoter methylation status of the p16INK4A tumor-suppressor gene was detected by methylation-specific polymerase chain reaction and on p16 protein level was analyzed with western blotting.Results The HepG2/GFP-HBx cells showed significantly higher cell proliferation at 72 hrs of culture (3.225 ± 0.038 A490) than either control (HepG2:2.012 ± 0.022 A490,t =-46.86,P < 0.001; HepG2/GFP:2.038 ± 0.029 A490,t =42.51,P < 0.001).The HepG2/GFP-HBx cells also showed significantly lower proportion of cells in the G0/G1 phase (16.45% ± 0.45%) than either control (HepG2:44.81% ± 1.36%,t =-34.202,P < 0.001; HepG2/GFP:42.76% ± 1.58%,t =-28.88,P < 0.001).However,5-Aza-CdR treatment did lead to a significant amount of HepG2/GFP-HBx cells being arrested in the G0/G1 phase (33.25% ± 0.79%,t =31.85,P < 0.001).The p16INK4A promoter was methylated in the HepG2/GFP-HBx cells,and became demithylation after treatment with 5-Aza-CdR.However,no methylation of p16INK4A promoter was observed in both HepG2 and HepG2/GFP cells.The p16 protein level was significantly lower in the HepG2/GFP-HBx (vs.HepG2 and HepG2/GFP cells) and this level increased after treatment with 5-Aza-CdR.Conclusion HBx protein promotes hepatocellular carcinoma cell cycle progression and growth by shortening the G0/G1 phase,and the underlying mechanism may involve inducing p16INK4A

  6. Effects of cell cycle activation on the short-term engraftment properties of ex vivo expanded murine hematopoietic cells.

    Science.gov (United States)

    Szilvassy, S J; Meyerrose, T E; Grimes, B

    2000-05-01

    Loss of long-term hematopoietic stem cell function in vitro is associated with cell cycle progression. To determine whether cytokine-induced proliferation also limits the rate of short-term engraftment and potential clinical utility of ex vivo expanded hematopoietic cells, murine Sca-1(+)c-kit(+)Lin(-) cells were cultured in interleukin-6 (IL-6), IL-11, granulocyte colony-stimulating factor (G-CSF), stem cell factor, flk-2 ligand, and thrombopoietin for 7 days. Cells amplified 2000-fold were then stained with Hoechst 33342, separated into G(0)/G(1) (72% +/- 3%) or S/G(2)/M (27% +/- 3%) fractions by flow sorting, and injected into lethally irradiated mice. Although long-term (more than 6 months) engraftment of lymphoid and myeloid lineages was greater in primary and secondary recipients of expanded cells residing in G(0)/G(1) at the time of transplantation, there were no noted differences in the short-term (less than 6 weeks) recovery kinetics of circulating blood cells. When hematopoietic cells were expanded in cultures containing the tetrapeptide stem cell inhibitor N-Acetyl-Ser-Asp-Lys-Pro (AcSDKP) to reduce progenitor cycling prior to transplantation, again there were no differences observed in short-term reconstitution by inhibited or uninhibited cells. Interestingly, AcSDKP significantly accelerated engraftment by expanded hematopoietic cells when administered in vivo at the time of transplantation. Leukocytes recovered to 20% of normal levels approximately 1 week faster, and thrombocytopenia was largely abrogated in AcSDKP-treated versus untreated mice. Therefore, while AcSDKP can accelerate the engraftment of ex vivo expanded hematopoietic progenitors, which suggests a relatively simple approach to improve their clinical utility, its effects appear unrelated to cell cycle arrest. (Blood. 2000;95:2829-2837) PMID:10779428

  7. Genomic analysis reveals a potential role for cell cycle perturbation in HCV-mediated apoptosis of cultured hepatocytes.

    Directory of Open Access Journals (Sweden)

    Kathie-Anne Walters

    2009-01-01

    Full Text Available The mechanisms of liver injury associated with chronic HCV infection, as well as the individual roles of both viral and host factors, are not clearly defined. However, it is becoming increasingly clear that direct cytopathic effects, in addition to immune-mediated processes, play an important role in liver injury. Gene expression profiling during multiple time-points of acute HCV infection of cultured Huh-7.5 cells was performed to gain insight into the cellular mechanism of HCV-associated cytopathic effect. Maximal induction of cell-death-related genes and appearance of activated caspase-3 in HCV-infected cells coincided with peak viral replication, suggesting a link between viral load and apoptosis. Gene ontology analysis revealed that many of the cell-death genes function to induce apoptosis in response to cell cycle arrest. Labeling of dividing cells in culture followed by flow cytometry also demonstrated the presence of significantly fewer cells in S-phase in HCV-infected relative to mock cultures, suggesting HCV infection is associated with delayed cell cycle progression. Regulation of numerous genes involved in anti-oxidative stress response and TGF-beta1 signaling suggest these as possible causes of delayed cell cycle progression. Significantly, a subset of cell-death genes regulated during in vitro HCV infection was similarly regulated specifically in liver tissue from a cohort of HCV-infected liver transplant patients with rapidly progressive fibrosis. Collectively, these data suggest that HCV mediates direct cytopathic effects through deregulation of the cell cycle and that this process may contribute to liver disease progression. This in vitro system could be utilized to further define the cellular mechanism of this perturbation.

  8. Loss of C/EBP alpha cell cycle control increases myeloid progenitor proliferation and transforms the neutrophil granulocyte lineage

    DEFF Research Database (Denmark)

    Porse, Bo T; Bryder, David; Theilgaard-Mönch, Kim; Hasemann, Marie S; Anderson, Kristina; Damgaard, Inge; Jacobsen, Sten Eirik W; Nerlov, Claus

    2005-01-01

    dissociate the ability of C/EBP alpha to block cell cycle progression through E2F inhibition from its function as a transcriptional activator impair the in vivo development of the neutrophil granulocyte and adipose lineages. We now show that such mutations increase the capacity of bone marrow (BM) myeloid...

  9. Effects of cell cycle noise on excitable gene circuits

    CERN Document Server

    Veliz-Cuba, Alan; Bennett, Matthew R; Josić, Krešimir; Ott, William

    2016-01-01

    We assess the impact of cell cycle noise on gene circuit dynamics. For bistable genetic switches and excitable circuits, we find that transitions between metastable states most likely occur just after cell division and that this concentration effect intensifies in the presence of transcriptional delay. We explain this concentration effect with a 3-states stochastic model. For genetic oscillators, we quantify the temporal correlations between daughter cells induced by cell division. Temporal correlations must be captured properly in order to accurately quantify noise sources within gene networks.

  10. Dux4 induces cell cycle arrest at G1 phase through upregulation of p21 expression

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Hongliang; Wang, Zhaoxia; Jin, Suqin; Hao, Hongjun [Department of Neurology, Peking University First Hospital, Beijing 100034 (China); Zheng, Lemin [The Institute of Cardiovascular Sciences, Peking University Health Science Center, Key Laboratory of Molecular Cardiovascular Sciences of Education Ministry, Key Laboratory of Cardiovascular Molecular Biology and Regulatory Peptides of Health Ministry, Beijing 100191 (China); Zhou, Boda [The Department of Cardiology, Peking University Third Hospital, Beijing 100191 (China); Zhang, Wei; Lv, He [Department of Neurology, Peking University First Hospital, Beijing 100034 (China); Yuan, Yun, E-mail: yuanyun2002@sohu.com [Department of Neurology, Peking University First Hospital, Beijing 100034 (China)

    2014-03-28

    Highlights: • Dux4 induced TE671 cell proliferation defect and G1 phase arrest. • Dux4 upregulated p21 expression without activating p53. • Silencing p21 rescued Dux4 mediated proliferation defect and cell cycle arrest. • Sp1 binding site was required for Dux4-induced p21 promoter activation. - Abstract: It has been implicated that Dux4 plays crucial roles in development of facioscapulohumeral dystrophy. But the underlying myopathic mechanisms and related down-stream events of this retrogene were far from clear. Here, we reported that overexpression of Dux4 in a cell model TE671 reduced cell proliferation rate, and increased G1 phase accumulation. We also determined the impact of Dux4 on p53/p21 signal pathway, which controls the checkpoint in cell cycle progression. Overexpression of Dux4 increased p21 mRNA and protein level, while expression of p53, phospho-p53 remained unchanged. Silencing p21 rescued Dux4 mediated proliferation defect and cell cycle arrest. Furthermore, we demonstrated that enhanced Dux4 expression increased p21 promoter activity and elevated expression of Sp1 transcription factor. Mutation of Sp1 binding site decreased dux4 induced p21 promoter activation. Chromatin immunoprecipitation (ChIP) assays confirmed the Dux4-induced binding of Sp1 to p21 promoter in vivo. These results suggest that Dux4 might induce proliferation inhibition and G1 phase arrest through upregulation of p21.

  11. 2015 Annual Progress Report: DOE Hydrogen and Fuel Cells Program

    Energy Technology Data Exchange (ETDEWEB)

    None

    2015-12-23

    The 2015 Annual Progress Report summarizes fiscal year 2015 activities and accomplishments by projects funded by the DOE Hydrogen and Fuel Cells Program. It covers the program areas of hydrogen production; hydrogen delivery; hydrogen storage; fuel cells; manufacturing R&D; technology validation; safety, codes and standards; systems analysis; and market transformation.

  12. Research progress of adult cardiac stem cells

    OpenAIRE

    Zheng, Nan; Ning-kun ZHANG; Lian-ru GAO

    2013-01-01

    The traditional view is that the heart is a terminal organ. This dogma, however, has been widely questioned with the discovery of adult cardiac stem cells (CSCs). Since CSCs have a highly self-renewal capacity and specific myocardial differentiation potential, nowadays they have been regarded as the most promising type of stem cells used in ischemic heart disease and other replacement therapy of end-stage heart disease. The present paper will focus on current results of scientific research on...

  13. A Coarse Estimation of Cell Size Region from a Mesoscopic Stochastic Cell Cycle Model

    Institute of Scientific and Technical Information of China (English)

    YI Ming; JIA Ya; LIU Quan; ZHU Chun-Lian; YANG Li-Jian

    2007-01-01

    Based on a deterministic cell cycle model of fission yeast, the effects of the finite cell size on the cell cycle regulation in wee1- cdc25△ double mutant type are numerically studied by using of the chemical Langevin equations. It is found that at a certain region of cell size, our numerical results from the chemical Langevin equations are in good qualitative agreement with the experimental observations. The two resettings to the G2 phase from early stages of mitosis can be induced under the moderate cell size. The quantized cycle times can be observed during such a cell size region. Therefore, a coarse estimation of cell size is obtained from the mesoscopic stochastic cell cycle model.

  14. Recent progress in micromorph solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Meier, J.; Dubail, S.; Cuperus, J.; Kroll, U.; Platz, R.; Torres, P.; Anna Selvan, J.A.; Pernet, P.; Beck, N.; Pellaton Vaucher, N.; Hof, Ch.; Fischer, D.; Keppner, H.; Shah, A. [Institut de Microtechnique IMT, A.-L. Breguet 2, Universite de Neuchatel, CH-2000 Neuchatel (Switzerland)

    1998-05-11

    Recently, we have demonstrated that intrinsic hydrogenated microcrystalline silicon, as deposited by the very high frequency glow-discharge technique, can be used as the active layers of p-i-n solar cells. Our microcrystalline silicon represents a new form of thin film crystalline silicon that can be deposited (in contrast to any other approach found in literature) at substrate temperatures as low as 200C. The combination of amorphous and microcrystalline material leads to a `real` silicon-based tandem structure, which we label `micromorph` cell. Meanwhile, stabilised efficiencies of 10.7% have been confirmed. In this paper, we present an improved micromorph tandem cell with 12% stabilised efficiency measured under outdoor conditions. Dark conductivity and combined SIMS measurements performed on intrinsic microcrystalline silicon layers reveal a post-oxidation of the film surface. However, a perfect chemical stability of entire microcrystalline cells as well as micromorph cells is presented. Variations of the p/i interface treatment show that an increase of the open circuit voltages from 450 mV up to 568 mV are achievable for microcrystalline cells, but such devices have reduced fill factors

  15. Progress in glial cell studies in some laboratories in China

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    Glial cells in the central nervous system(CNS) consist of a heterogeneous population of cell types,each characterized by distinct morphological features,physiological properties,and specific markers.In contrast to the previous view that glial cells were passive elements in the brain,accumulating evidence suggests that glial cells are active participants in various brain functions and brain disorders.This review summarizes recent progress of glial cell studies from several groups in China,ranging from studies about the mechanisms of neuron-glia crosstalking to investigations on the roles of glial cells in various CNS disorders.

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

    DEFF Research Database (Denmark)

    Rokni, Masoud

    2010-01-01

    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...... 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...... 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...

  17. Expression and clinical role of NF45 as a novel cell cycle protein in esophageal squamous cell carcinoma (ESCC).

    Science.gov (United States)

    Ni, Sujie; Zhu, Junya; Zhang, Jianguo; Zhang, Shu; Li, Mei; Ni, Runzhou; Liu, Jinxia; Qiu, Huiyuan; Chen, Wenjuan; Wang, Huijie; Guo, Weijian

    2015-02-01

    NF45 (also known as ILF2), as one subunit of NF-AT (nuclear factor of activated T cells), repairs DNA breaks, inhibits viral replication, and also functions as a negative regulator in the microRNA processing pathway in combination with NF90. Recently, it was found that implicated in the mitotic control of HeLa cells and deletion of endogenous NF45 decreases growth of HeLa cells. While the role of NF45 in cancer biology remains under debate. In this study, we analyzed the expression and clinical significance of NF45 in esophageal squamous cell carcinoma ESCC. The expression of NF45 was evaluated by Western blot in 8 paired fresh ESCC tissues and immunohistochemistry on 105 paraffin-embedded slices. NF45 was highly expressed in ESCC and significantly associated with ESCC cells tumor stage and Ki-67. Besides, high NF45 expression was an independent prognostic factor for ESCC patients' poor survival. To determine whether NF45 could regulate the proliferation of ESCC cells, we increased endogenous NF45 and analyzed the proliferation of TE1 ESCC cells using Western blot, CCK8, flow cytometry assays and colony formation analyses, which together indicated that overexpression of NF45 favors cell cycle progress of TE1 ESCC cells. While knockdown of NF45 resulted in cell cycle arrest at G0/G1-phase and thus abolished the cell growth. These findings suggested that NF45 might play an important role in promoting the tumorigenesis of ESCC, and thus be a promising therapeutic target to prevent ESCC progression. PMID:25286760

  18. Low-density microarray analysis of TGFβ1-dependent cell cycle regulation in human breast adenocarcinoma MCF7 cell line

    Directory of Open Access Journals (Sweden)

    Dubrovska A. M.

    2014-03-01

    Full Text Available Transforming growth factor β1 (TGFβ1 is a growth regulator that has antiproliferative effects on a range of epithelial cells at the early stages and promoting tumorigenesis at the later stages of cancer progression. The molecular mechanisms of a duel role of TGFβ1 in tumor growth regulation remain poorly understood. Aim. To analyze the TGFβ1-dependent cell cycle regulation of tumorigenic breast epithelial cells. Methods. Our present study was designed to examine the regulatory effect of TGFβ1 on the expression of a panel of 96 genes which are known to be critically involved in cell cycle regulation. GEArray Q series Human Cell Cycle Gene Array was applied to profile the gene expression changes in MCF7 human breast adenocarcinoma cell line treated with TGFβ1. Results. The gene expression array data enabled us to reveal the molecular regulators that might connect TGFβ1 signaling to the promoting of the tumor growth, e. g. retinoblastoma protein (pRB1, check-point kinase 2 (Chk2, breast cancer 1, early onset (BRCA1, DNA damage checkpoint protein RAD9, cyclin-dependent kinase 2 (CDK2, cyclin D1 (CCND1. Conclusions. The uncovering of the key signaling modules involved in TGFβ1- dependent signaling might provide an insight into the mechanisms of TGFβ1-dependent tumor growth and can be beneficial for the development of novel therapeutic approaches.

  19. Outcome of treatment of human HeLa cervical cancer cells with roscovitine strongly depends on the dosage and cell cycle status prior to the treatment.

    Science.gov (United States)

    Wesierska-Gadek, Józefa; Borza, Andreea; Walzi, Eva; Krystof, Vladimir; Maurer, Margarita; Komina, Oxana; Wandl, Stefanie

    2009-04-01

    Exposure of asynchronously growing human HeLa cervical carcinoma cells to roscovitine (ROSC), a selective cyclin-dependent kinases (CDKs) inhibitor, arrests their progression at the transition between G(2)/M and/or induces apoptosis. The outcome depends on the ROSC concentration. At higher dose ROSC represses HPV-encoded E7 oncoprotein and initiates caspase-dependent apoptosis. Inhibition of the site-specific phosphorylation of survivin and Bad, occurring at high-dose ROSC treatment, precedes the onset of apoptosis and seems to be a prerequisite for cell death. Considering the fact that in HeLa cells the G(1)/S restriction checkpoint is abolished by E7, we addressed the question whether the inhibition of CDKs by pharmacological inhibitors in synchronized cells would be able to block the cell-cycle in G(1) phase. For this purpose, we attempted to synchronize cells by serum withdrawal or by blocking of the mitotic apparatus using nocodazole. Unlike human MCF-7 cells, HeLa cells do not undergo G(1) block after serum starvation, but respond with a slight increase of the ratio of G(1) population. Exposure of G(1)-enriched HeLa cells to ROSC after re-feeding does not block their cell-cycle progression at G(1)-phase, but increases the ratio of S- and G(2)-phase, thereby mimicking the effect on asynchronously growing cells. A quite different impact is observed after treatment of HeLa cells released from mitotic block. ROSC prevents their cell cycle progression and cells transiently accumulate in G(1)-phase. These results show that inhibition of CDKs by ROSC in cells lacking the G(1)/S restriction checkpoint has different outcomes depending on the cell-cycle status prior to the onset of treatment. PMID:19180585

  20. Life cycle assessment of hydrogen production and fuel cell systems

    International Nuclear Information System (INIS)

    This paper details life cycle assessment (LCA) of hydrogen production and fuel cell system. LCA is a key tool in hydrogen and fuel cell technologies for design, analysis, development; manufacture, applications etc. Energy efficiencies and greenhouse gases and air pollution emissions have been evaluated in all process steps including crude oil and natural gas pipeline transportation, crude oil distillation, natural gas reprocessing, wind and solar electricity generation , hydrogen production through water electrolysis and gasoline and hydrogen distribution and utilization

  1. Cell cycle control in Plasmodium falciparum: a genomics perspective

    OpenAIRE

    Waters, A. P.; Janse, C.J.; Doerig, Christian; Chakrabarti, Debopam

    2004-01-01

    The molecular mechanisms regulating cell proliferation and development in malaria parasites are still largely unknown. Phenomenological observations, pertaining to the organisation of the cell cycle during schizogony or to the signal transduction pathways whose activation is responsible for the developmental stage transitions, can now be complemented with information gathered from genomic databases. The PlasmoDB database has been used extensively to identify putative homologues of a number of...

  2. Testing a Mathematical Model of the Yeast Cell Cycle

    OpenAIRE

    Cross, Frederick R.; Archambault, Vincent; Miller, Mary; Klovstad, Martha

    2002-01-01

    We derived novel, testable predictions from a mathematical model of the budding yeast cell cycle. A key qualitative prediction of bistability was confirmed in a strain simultaneously lacking cdc14 and G1 cyclins. The model correctly predicted quantitative dependence of cell size on gene dosage of the G1 cyclin CLN3, but it incorrectly predicted strong genetic interactions between G1 cyclins and the anaphase- promoting complex specificity factor Cdh1. To provide cons...

  3. Intercellular communication is cell cycle modulated during early Xenopus laevis development

    OpenAIRE

    1990-01-01

    We investigated intercellular communication during the seventh and tenth cell cycles of Xenopus laevis development using microinjection of Lucifer yellow and FITC-dextran as well as freeze-fracture electron microscopy. We found that gap junction-mediated dye coupling visualized using Lucifer yellow was strongly cell cycle modulated in the tenth cell cycle. Cytoplasmic bridge-mediated dye coupling visualized via FITC-dextran was also, of course, cell cycle modulated. The basis of cell cycle-mo...

  4. Current progress and prospects of induced pluripotent stem cells

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    Induced pluripotent stem(iPS) cells are derived from somatic cells by ectopic expression of few transcription factors.Like embryonic stem(ES) cells,iPS cells are able to self-renew indefinitely and to differentiate into all types of cells in the body.iPS cells hold great promise for regenerative medicine,because iPS cells circumvent not only immunological rejection but also ethical issues.Since the first report on the derivation of iPS cells in 2006,many laboratories all over the world started research on iPS cells and have made significant progress.This paper reviews recent progress in iPS cell research,including the methods to generate iPS cells,the molecular mechanism of reprogramming in the formation of iPS cells,and the potential applications of iPS cells in cell replacement therapy.Current problems that need to be addressed and the prospects for iPS research are also discussed.

  5. 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...

  6. Refined life-cycle assessment of polymer solar cells

    DEFF Research Database (Denmark)

    Lenzmann, F.; Kroon, J.; Andriessen, R.; Espinosa Martinez, Nieves; Garcia-Valverde, R.; Krebs, Frederik C; Ossenbrink, H.; Jager-Waldau, A.; Helm, P.

    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...

  7. The depletion of Interleukin-8 causes cell cycle arrest and increases the efficacy of docetaxel in breast cancer cells

    Energy Technology Data Exchange (ETDEWEB)

    Shao, Nan [Breast Disease Center, The First Affiliated Hospital, Sun Yat-Sen University, Guangzhou (China); Chen, Liu-Hua [Department of Minimally Invasive Surgery Center, The First Affiliated Hospital, Sun Yat-Sen University, Guangzhou (China); Ye, Run-Yi [Breast Disease Center, The First Affiliated Hospital, Sun Yat-Sen University, Guangzhou (China); Lin, Ying, E-mail: frostlin@hotmail.com [Breast Disease Center, The First Affiliated Hospital, Sun Yat-Sen University, Guangzhou (China); Wang, Shen-Ming, E-mail: shenmingwang@hotmail.com [Breast Disease Center, The First Affiliated Hospital, Sun Yat-Sen University, Guangzhou (China)

    2013-02-15

    Highlights: ► IL-8 depletion affects cell cycle distribution. ► Intrinsic IL-8 mediates breast cancer cell migration and invasion. ► IL-8 siRNA down regulates key factors that control survival and metastatic pathway. ► IL-8 depletion reduces integrin β3 expression. ► IL-8 depletion increases the chemosensitivity to docetaxel. -- Abstract: IL-8 is a multi-functional pro-inflammatory chemokine, which is highly expressed in cancers, such as ER-negative breast cancer. The present study demonstrates the pervasive role of IL-8 in the malignant progression of ER-negative breast cancer. IL-8 siRNA inhibited proliferation and delayed the G1 to S cell cycle progression in MDA-MB-231 and BT549 cells. IL-8 silencing resulted in the upregulation of the CDK inhibitor p27, the downregulation of cyclin D1, and the reduction of phosphorylated-Akt and NF-κB activities. IL-8 depletion also increased the chemosensitivity to docetaxel. These results indicate a role for IL-8 in promoting tumor cell survival and resistance to docetaxel and highlight the potential therapeutic significance of IL-8 depletion in ER-negative breast cancer patients.

  8. Research progress of adult cardiac stem cells

    Directory of Open Access Journals (Sweden)

    Nan ZHENG

    2013-04-01

    Full Text Available The traditional view is that the heart is a terminal organ. This dogma, however, has been widely questioned with the discovery of adult cardiac stem cells (CSCs. Since CSCs have a highly self-renewal capacity and specific myocardial differentiation potential, nowadays they have been regarded as the most promising type of stem cells used in ischemic heart disease and other replacement therapy of end-stage heart disease. The present paper will focus on current results of scientific research on human adult CSCs and epicardium-derived cell (EPDC, as well as the treatment strategies in the field of cardiac regeneration, and the problems and prospect disclosed in the research.

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

    Directory of Open Access Journals (Sweden)

    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. Piperlongumine Suppresses Proliferation of Human Oral Squamous Cell Carcinoma through Cell Cycle Arrest, Apoptosis and Senescence.

    Science.gov (United States)

    Chen, San-Yuan; Liu, Geng-Hung; Chao, Wen-Ying; Shi, Chung-Sheng; Lin, Ching-Yen; Lim, Yun-Ping; Lu, Chieh-Hsiang; Lai, Peng-Yeh; Chen, Hau-Ren; Lee, Ying-Ray

    2016-01-01

    Oral squamous cell carcinoma (OSCC), an aggressive cancer originating in the oral cavity, is one of the leading causes of cancer deaths in males worldwide. This study investigated the antitumor activity and mechanisms of piperlongumine (PL), a natural compound isolated from Piper longum L., in human OSCC cells. The effects of PL on cell proliferation, the cell cycle, apoptosis, senescence and reactive oxygen species (ROS) levels in human OSCC cells were investigated. PL effectively inhibited cell growth, caused cell cycle arrest and induced apoptosis and senescence in OSCC cells. Moreover, PL-mediated anti-human OSCC behavior was inhibited by an ROS scavenger N-acetyl-l-cysteine (NAC) treatment, suggesting that regulation of ROS was involved in the mechanism of the anticancer activity of PL. These findings suggest that PL suppresses tumor growth by regulating the cell cycle and inducing apoptosis and senescence and is a potential chemotherapy agent for human OSCC cells. PMID:27120594

  11. Piperlongumine Suppresses Proliferation of Human Oral Squamous Cell Carcinoma through Cell Cycle Arrest, Apoptosis and Senescence

    Directory of Open Access Journals (Sweden)

    San-Yuan Chen

    2016-04-01

    Full Text Available Oral squamous cell carcinoma (OSCC, an aggressive cancer originating in the oral cavity, is one of the leading causes of cancer deaths in males worldwide. This study investigated the antitumor activity and mechanisms of piperlongumine (PL, a natural compound isolated from Piper longum L., in human OSCC cells. The effects of PL on cell proliferation, the cell cycle, apoptosis, senescence and reactive oxygen species (ROS levels in human OSCC cells were investigated. PL effectively inhibited cell growth, caused cell cycle arrest and induced apoptosis and senescence in OSCC cells. Moreover, PL-mediated anti-human OSCC behavior was inhibited by an ROS scavenger N-acetyl-l-cysteine (NAC treatment, suggesting that regulation of ROS was involved in the mechanism of the anticancer activity of PL. These findings suggest that PL suppresses tumor growth by regulating the cell cycle and inducing apoptosis and senescence and is a potential chemotherapy agent for human OSCC cells.

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

    International Nuclear Information System (INIS)

    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.

  13. All delays before radiotherapy risk progression of Merkel cell carcinoma

    International Nuclear Information System (INIS)

    Prolonged waiting times for radiotherapy have resulted in many centres assigning priorities to various patient or diagnostic groups. A high risk of progression on a waiting list is one factor that would reasonably influence the priority. The present descriptive study of 27 patients with Merkel cell carcinoma (MCC) found that a median wait of 24 days for radiotherapy is associated with a high risk of progression. Eleven (41%) of 27 patients developed progressive disease, including five (45%) of 11 patients waiting for adjuvant radiotherapy. Patients treated adjuvantly also had longer waiting times prior to their initial radiotherapy consultation (median 41 days), which may have contributed to the rate of progression. Merkel cell carcinoma is an aggressive but curable malignancy and appropriate management should include efforts to minimize all potential delays prior to the commencement of radiotherapy. Copyright (2004) Blackwell Science Pty Ltd

  14. Helquat dye for staining dead cells, fluorescence activated cell sorting (FACS) and cell cycle analysis

    Czech Academy of Sciences Publication Activity Database

    Joshi, Vishwas; Kužmová, Erika; Kozák, Jaroslav; Bednárová, Lucie; Císařová, I.; Hájek, Miroslav; Teplý, Filip

    Praha: Czech Chemical Society, 2015. s. 86. [Liblice 2015. Advances in Organic , Bioorganic and Pharmaceutical Chemistry /50./. 06.11.2015-08.11.2015, Olomouc] R&D Projects: GA ČR GA13-19213S Institutional support: RVO:61388963 Keywords : helquat dye * FACS * cell cycle analysis Subject RIV: CC - Organic Chemistry

  15. The Interplay between Cell Wall Mechanical Properties and the Cell Cycle in Staphylococcus aureus

    OpenAIRE

    Bailey, Richard G.; Turner, Robert D.; Mullin, Nic; Clarke, Nigel,; Foster, Simon J.; Hobbs, Jamie K.

    2014-01-01

    The nanoscale mechanical properties of live Staphylococcus aureus cells during different phases of growth were studied by atomic force microscopy. Indentation to different depths provided access to both local cell wall mechanical properties and whole-cell properties, including a component related to cell turgor pressure. Local cell wall properties were found to change in a characteristic manner throughout the division cycle. Splitting of the cell into two daughter cells followed a local softe...

  16. Rapid alterations of cell cycle control proteins in human T lymphocytes in microgravity

    Directory of Open Access Journals (Sweden)

    Thiel Cora S

    2012-01-01

    Full Text Available Abstract In our study we aimed to identify rapidly reacting gravity-responsive mechanisms in mammalian cells in order to understand if and how altered gravity is translated into a cellular response. In a combination of experiments using "functional weightlessness" provided by 2D-clinostats and real microgravity provided by several parabolic flight campaigns and compared to in-flight-1g-controls, we identified rapid gravity-responsive reactions inside the cell cycle regulatory machinery of human T lymphocytes. In response to 2D clinorotation, we detected an enhanced expression of p21 Waf1/Cip1 protein within minutes, less cdc25C protein expression and enhanced Ser147-phosphorylation of cyclinB1 after CD3/CD28 stimulation. Additionally, during 2D clinorotation, Tyr-15-phosphorylation occurred later and was shorter than in the 1 g controls. In CD3/CD28-stimulated primary human T cells, mRNA expression of the cell cycle arrest protein p21 increased 4.1-fold after 20s real microgravity in primary CD4+ T cells and 2.9-fold in Jurkat T cells, compared to 1 g in-flight controls after CD3/CD28 stimulation. The histone acetyltransferase (HAT inhibitor curcumin was able to abrogate microgravity-induced p21 mRNA expression, whereas expression was enhanced by a histone deacetylase (HDAC inhibitor. Therefore, we suppose that cell cycle progression in human T lymphocytes requires Earth gravity and that the disturbed expression of cell cycle regulatory proteins could contribute to the breakdown of the human immune system in space.

  17. Conditional inactivation of PDCD2 induces p53 activation and cell cycle arrest

    Directory of Open Access Journals (Sweden)

    Celine J. Granier

    2014-08-01

    Full Text Available PDCD2 (programmed cell death domain 2 is a highly conserved, zinc finger MYND domain-containing protein essential for normal development in the fly, zebrafish and mouse. The molecular functions and cellular activities of PDCD2 remain unclear. In order to better understand the functions of PDCD2 in mammalian development, we have examined PDCD2 activity in mouse blastocyst embryos, as well as in mouse embryonic stem cells (ESCs and embryonic fibroblasts (MEFs. We have studied mice bearing a targeted PDCD2 locus functioning as a null allele through a splicing gene trap, or as a conditional knockout, by deletion of exon2 containing the MYND domain. Tamoxifen-induced knockout of PDCD2 in MEFs, as well as in ESCs, leads to defects in progression from the G1 to the S phase of cell cycle, associated with increased levels of p53 protein and p53 target genes. G1 prolongation in ESCs was not associated with induction of differentiation. Loss of entry into S phase of the cell cycle and marked induction of nuclear p53 were also observed in PDCD2 knockout blastocysts. These results demonstrate a unique role for PDCD2 in regulating the cell cycle and p53 activation during early embryonic development of the mouse.

  18. MHD Integrated Topping Cycle Project. Sixteenth quarterly technical progress report, May 1991--July 1991

    Energy Technology Data Exchange (ETDEWEB)

    1992-03-01

    The Magnetohydrodynamics (MHD) Integrated Topping Cycle (ITC) Project represents the culmination of the proof-of-concept (POC) development stage in the US Department of Energy (DOE) program to advance MHD technology to early commercial development stage utility power applications. The project is a joint effort, combining the skills of three topping cycle component developers: TRW, Avco/TDS, and Westinghouse. TRW, the prime contractor and system integrator, is responsible for the 50 thermal megawatt (50 MW{sub t}) slagging coal combustion subsystem. Avco/TDS is responsible for the MHD channel subsystem (nozzle, channel, diffuser, and power conditioning circuits), and Westinghouse is responsible for the current consolidation subsystem. The ITC Project will advance the state-of-the-art in MHD power systems with the design, construction, and integrated testing of 50 MW{sub t} power train components which are prototypical of the equipment that will be used in an early commercial scale MHD utility retrofit. Long duration testing of the integrated power train at the Component Development and Integration Facility (CDIF) in Butte, Montana will be performed, so that by the early 1990`s, an engineering data base on the reliability, availability, maintainability and performance of the system will be available to allow scaleup of the prototypical designs to the next development level. This Sixteenth Quarterly Technical Progress Report covers the period May 1, 1991 to July 31, 1991.

  19. Plutonium and neptunium stripping in single cycle solvent extraction flowsheets: recent progress in flowsheet testing

    International Nuclear Information System (INIS)

    The use of single cycle solvent extraction flowsheets and centrifugal contactors are key objectives in the development of advanced processes for spent fuel and waste processing in future closed fuel cycles. These advances lead to intensified processes, reducing the costs of plants and the volumes of wastes arising. By adopting other flowsheet changes, such as reduced fission product decontamination factors, U/Pu co-processing and Pu/Np co-stripping, further improvements can be made addressing issues such as proliferation resistance and minor actinide burning, without adverse effects on the products. The cost-effective development of such flowsheets benefits from an understanding of the underlying process chemistry coupled with powerful modelling and simulation techniques. These can then be combined with a limited number of miniature scale solvent extraction trials to develop, optimise and ultimately define flowsheet envelopes for larger scale and/or fully active testing, if required. This paper reports recent progress made in the development of flowsheets for the co-stripping of Pu and Np from U in so-called advanced Purex processes using centrifugal contactors. In particular, the use of simple hydroxamic acids to strip both Pu and Np using complexation and reduction is considered with reference to solvent extraction trials in a miniature centrifugal contactor rig. These data are suitable for evaluation using process models with identification of significant parameters including distribution data, mass transfer rates and chemical kinetics. (authors)

  20. MHD Integrated Topping Cycle Project. Fourteenth quarterly technical progress report, November 1, 1990-- January 31, 1991

    Energy Technology Data Exchange (ETDEWEB)

    1992-02-01

    This fourteenth quarterly technical progress report of the MHD Integrated Topping Cycle Project presents the accomplishments during the period November 1, 1990 to January 31, 1991. Testing of the High Pressure Cooling Subsystem electrical isolator was completed. The PEEK material successfully passed the high temperature, high pressure duration tests (50 hours). The Combustion Subsystem drawings were CADAM released. The procurement process is in progress. An equipment specification and RFP were prepared for the new Low Pressure Cooling System (LPCS) and released for quotation. Work has been conducted on confirmation tests leading to final gas-side designs and studies to assist in channel fabrication.The final cathode gas-side design and the proposed gas-side designs of the anode and sidewall are presented. Anode confirmation tests and related analyses of anode wear mechanisms used in the selection of the proposed anode design are presented. Sidewall confirmation tests, which were used to select the proposed gas-side design, were conducted. The design for the full scale CDIF system was completed. A test program was initiated to investigate the practicality of using Avco current controls for current consolidation in the power takeoff (PTO) regions and to determine the cause of past current consolidation failures. Another important activity was the installation of 1A4-style coupons in the 1A1 channel. A description of the coupons and their location with 1A1 channel is presented herein.

  1. Anticancer effect of arsenite on cell migration, cell cycle and apoptosis in human pancreatic cancer cells

    Science.gov (United States)

    HORIBE, YOHEI; ADACHI, SEIJI; YASUDA, ICHIRO; YAMAUCHI, TAKAHIRO; KAWAGUCHI, JUNJI; KOZAWA, OSAMU; SHIMIZU, MASAHITO; MORIWAKI, HISATAKA

    2016-01-01

    The standard treatment for advanced pancreatic cancer is chemotherapy, but its clinical outcome remains unsatisfactory. Therefore, the development of novel treatments for this malignancy is urgently required. In the present study, the anticancer effect of arsenite on platelet-derived growth factor (PDGF)-BB-induced migration, cell cycle and apoptosis was investigated in pancreatic cancer cells (AsPC-1 and BxPC-3), and compared with the effect on normal pancreatic epithelial (PE) cells. In the cell migration assay, arsenite clearly inhibited PDGF-BB-induced cell migration in AsPC-1 cells, but not in BxPC-3 or PE cells. Arsenite also caused cell apoptosis in AsPC-1 cells, but not in BxPC-3 or PE cells. In AsPC-1 cells, the levels of cyclin D1 and phosphorylated retinoblastoma protein decreased following treatment with arsenite, but this was not observed in BxPC-3 cells. To further examine the differences between these two cell lines, the effect of arsenite on upstream p44/p42 mitogen-activated protein kinase (MAPK) and Akt was investigated. PDGF-BB caused phosphorylation of p44/p42 MAPK and Akt in both cell lines. Pretreatment with arsenite significantly suppressed PDGF-BB-induced phosphorylation of Akt, but not of p44/p42 MAPK in AsPC-1 cells. By contrast, arsenite did not affect these molecules in BxPC-3 cells. Since the inhibition of the Akt signaling pathway markedly reduced PDGF-BB-induced migration in AsPC-1 cells, the present results strongly suggest that arsenite inhibits PDGF-BB-induced migration by suppressing the Akt signaling pathway in AsPC-1 cells. Therefore, arsenite may be a useful tool for the treatment of patients with certain types of pancreatic cancer, without causing adverse effects on normal pancreatic cells.

  2. Stem cells - biological update and cell therapy progress

    OpenAIRE

    GIRLOVANU, MIHAI; Susman, Sergiu; Soritau, Olga; RUS-CIUCA, DAN; MELINCOVICI, CARMEN; CONSTANTIN, ANNE-MARIE; Carmen Mihaela MIHU

    2015-01-01

    In recent years, the advances in stem cell research have suggested that the human body may have a higher plasticity than it was originally expected. Until now, four categories of stem cells were isolated and cultured in vivo: embryonic stem cells, fetal stem cells, adult stem cells and induced pluripotent stem cells (hiPSCs). Although multiple studies were published, several issues concerning the stem cells are still debated, such as: the molecular mechanisms of differentiation, the methods t...

  3. Potential for progress in carbon cycle modeling: models as tools and representations of reality (Invited)

    Science.gov (United States)

    Caldeira, K.

    2013-12-01

    attribution) Potential for progress in carbon-cycle modeling rests in being clear about the problems we seek to solve, and then developing tools to solve those problems. A global carbon cycle model that represents underlying complexity in all its detail may ultimately prove useless: 'We actually made a map of the country, on the scale of a mile to the mile!' 'Have you used it much?' I enquired. 'It has never been spread out, yet,' said Mein Herr: 'the farmers objected: they said it would cover the whole country, and shut out the sunlight! So we now use the country itself, as its own map, and I assure you it does nearly as well.' - Lewis Carroll

  4. Effects of sense and antisense centromere/kinetochore complex protein-B (CENP-B) in cell cycle regulation

    Institute of Scientific and Technical Information of China (English)

    LUO Song; LIN Haiyan; QI Jianguo; WANG Yongchao

    2005-01-01

    This paper investigates the effects of sense and antisense centromere/kinetochore complex protein-B (CENP-B) in cell cycle regulation. Full-length cenpb cDNA was subcloned into pBI-EGFP eukaryotic expression vector in both sense and antisense orientation. HeLa-Tet-Off cells were transfected with sense or antisense cenpb vectors. Sense transfection of HeLa-Tet-Off cells resulted in the formation of a large centromere/kinetochore complex, and apoptosis of cells following several times of cell division. A stable antisense cenpb transfected cell line, named HACPB, was obtained. The centromere/kinetochore complex of HACPB cells became smaller than control HeLa-Tet-Off cells and scattered, and the expression of CENP-B was down-regulated. In addition, delayed cell cycle progression, inhibited malignant phenotype, restrained ability of tumor formation in nude mice, and delayed entry from G2/M phase into next G1 phase were observed in HACPB cells. Furthermore, the expression of cyclin-dependent kinases (CDKs), cyclins, and CDK inhibitors (CKIs) were modulated during different phases of the cell cycle. CENP-B is an essential protein for the maintenance of the structure and function of centromere/kinetochore complex, and plays important roles in cell cycle regulation.

  5. Andrographolide inhibits prostate cancer by targeting cell cycle regulators, CXCR3 and CXCR7 chemokine receptors.

    Science.gov (United States)

    Mir, Hina; Kapur, Neeraj; Singh, Rajesh; Sonpavde, Guru; Lillard, James W; Singh, Shailesh

    2016-01-01

    Despite state of the art cancer diagnostics and therapies offered in clinic, prostate cancer (PCa) remains the second leading cause of cancer-related deaths. Hence, more robust therapeutic/preventive regimes are required to combat this lethal disease. In the current study, we have tested the efficacy of Andrographolide (AG), a bioactive diterpenoid isolated from Andrographis paniculata, against PCa. This natural agent selectively affects PCa cell viability in a dose and time-dependent manner, without affecting primary prostate epithelial cells. Furthermore, AG showed differential effect on cell cycle phases in LNCaP, C4-2b and PC3 cells compared to retinoblastoma protein (RB(-/-)) and CDKN2A lacking DU-145 cells. G2/M transition was blocked in LNCaP, C4-2b and PC3 after AG treatment whereas DU-145 cells failed to transit G1/S phase. This difference was primarily due to differential activation of cell cycle regulators in these cell lines. Levels of cyclin A2 after AG treatment increased in all PCa cells line. Cyclin B1 levels increased in LNCaP and PC3, decreased in C4-2b and showed no difference in DU-145 cells after AG treatment. AG decreased cyclin E2 levels only in PC3 and DU-145 cells. It also altered Rb, H3, Wee1 and CDC2 phosphorylation in PCa cells. Intriguingly, AG reduced cell viability and the ability of PCa cells to migrate via modulating CXCL11 and CXCR3 and CXCR7 expression. The significant impact of AG on cellular and molecular processes involved in PCa progression suggests its potential use as a therapeutic and/or preventive agent for PCa. PMID:27029529

  6. Current progress and prospects of induced pluripotent stem cells

    Institute of Scientific and Technical Information of China (English)

    CHEN LingYi; Liu Lin

    2009-01-01

    Induced pluripotent stem (iPS) cells are derived from somatic cells by ectopic expression of few transcription factors. Like embryonic stem (ES) cells, iPS cells are able to self-renew indefinitely and to differentiate into all types of cells in the body. iPS cells hold great promise for regenerative medicine,because iPS ceils circumvent not only immunological rejection but also ethical issues. Since the first report on the derivation of iPS cells in 2006, many laboratories all over the world started research on iPS cells and have made significant progress. This paper reviews recent progress in iPS cell research,Including the methods to generate iPS cells, the molecular mechanism of reprogramming in the formation of iPS ceils, and the potential applications of iPS cells in cell replacement therapy. Current problems that need to be addressed and the prospects for iPS research are also discussed.

  7. IARS2 silencing induces non-small cell lung cancer cells proliferation inhibition, cell cycle arrest and promotes cell apoptosis.

    Science.gov (United States)

    Yin, J; Liu, W; Li, R; Liu, J; Zhang, Y; Tang, W; Wang, K

    2016-01-01

    The purpose of this study was to investigate the potential role of Ileucyl-tRNA synthetase (IARS2) silencing in non-small cell lung cancer (NSCLC). The silencing of IARS2 in H1299 cells and A549 cells were performed by lentivirus encoding shRNAs. The efficiency of IARS2 silencing was detected by quantitative real time PCR and western blot. The effects of IARS2 silencing on cell growth, cell apoptosis, cell cycle and cell colony formation ability were assessed by cells counting, MTT assay, flow cytometer analysis and soft agar colony formation assay, respectively. Compared with negative control group, IARS2 was significantly knockdown by transfection with lentivirus encoding shRNA of IARS2. The IARS2 silencing significantly inhibited the cells proliferation and cells colony formation ability, induced cell cycle arrest at G1/S phase and promoted cell apoptosis. IARS2 silencing induced NSCLC cells growth inhibition, cell cycle arrest and promoted cell apoptosis. These results suggest that IARS2 may be a novel target for the treatment of NSCLC. PMID:26639235

  8. High efficiency carbonate fuel cell/turbine hybrid power cycles

    Energy Technology Data Exchange (ETDEWEB)

    Steinfeld, G. [Energy Research Corp., Danbury, CT (United States)

    1995-10-19

    Carbonate fuel cells developed by Energy Research Corporation, in commercial 2.85 MW size, have an efficiency of 57.9 percent. Studies of higher efficiency hybrid power cycles were conducted in cooperation with METC to identify an economically competitive system with an efficiency in excess of 65 percent. A hybrid power cycle was identified that includes a direct carbonate fuel cell, a gas turbine and a steam cycle, which generates power at a LHV efficiency in excess of 70 percent. This new system is called a Tandem Technology Cycle (TTC). In a TTC operating on natural gas fuel, 95 percent of the fuel is mixed with recycled fuel cell anode exhaust, providing water for the reforming of the fuel, and flows to a direct carbonate fuel cell system which generates 72 percent of the power. The portion of the fuel cell anode exhaust which is not recycled, is burned and heat is transferred to the compressed air from a gas turbine, raising its temperature to 1800{degrees}F. The stream is then heated to 2000{degrees}F in the gas turbine burner and expands through the turbine generating 13 percent of the power. Half the exhaust from the gas turbine flows to the anode exhaust burner, and the remainder flows to the fuel cell cathodes providing the O{sub 2} and CO{sub 2} needed in the electrochemical reaction. Exhaust from the fuel cells flows to a steam system which includes a heat recovery steam generator and stages steam turbine which generates 15 percent of the TTC system power. Studies of the TTC for 200-MW and 20-MW size plants quantified performance, emissions and cost-of-electricity, and compared the characteristics of the TTC to gas turbine combined cycles. A 200-MW TTC plant has an efficiency of 72.6 percent, and is relatively insensitive to ambient temperature, but requires a heat exchanger capable of 2000{degrees}F. The estimated cost of electricity is 45.8 mills/kWhr which is not competitive with a combined cycle in installations where fuel cost is under $5.8/MMBtu.

  9. An Aqueous Extract of Tuberaria lignosa Inhibits Cell Growth, Alters the Cell Cycle Profile, and Induces Apoptosis of NCI-H460 Tumor Cells.

    Science.gov (United States)

    Pereira, Joana M; Lopes-Rodrigues, Vanessa; Xavier, Cristina P R; Lima, M João; Lima, Raquel T; Ferreira, Isabel C F R; Vasconcelos, M Helena

    2016-01-01

    Tuberaria lignosa (Sweet) Samp. is found in European regions, and has antioxidant properties due to its composition in ascorbic acid and phenolic compounds. Given its traditional use and antioxidant properties, the tumor cell growth inhibitory potential of aqueous extracts from T. lignosa (prepared by infusion and decoction) was investigated in three human tumor cell lines: MCF-7 (breast adenocarcinoma), NCI-H460 (non-small cell lung cancer), and HCT-15 (human colorectal adenocarcinoma). Both extracts inhibited the growth of these cell lines; the most potent one being the T. lignosa extract obtained by infusion in the NCI-H460 cells (GI50 of approximately 50 μg/mL). Further assays were carried out with this extract in NCI-H460 cells. At 100 μg/mL or 150 μg/mL it caused an increase in the percentage of cells in the G0/G1 phase and a decrease of cells in S phase of the cell cycle. Additionally, these concentrations caused an increase in the percentage of apoptotic cells. In agreement, a decrease in total poly (ADP-ribose) polymerase (PARP) and pro-caspase 3 levels was found. In conclusion, the T. lignosa extract obtained by infusion was more potent in NCI-H460 cells, altering the cell cycle progression and inducing apoptosis. This work highlights the importance of T. lignosa as a source of bioactive compounds with tumor cell growth inhibitory potential. PMID:27164073

  10. Direct inhibition of Retinoblastoma phosphorylation by Nimbolide causes cell cycle arrest and suppresses glioblastoma growth

    Science.gov (United States)

    Anderson, Jane; Liu, Xiaona; Henry, Heather; Gasilina, Anjelika; Nassar, Nicholas; Ghosh, Jayeeta; Clark, Jason P; Kumar, Ashish; Pauletti, Giovanni M.; Ghosh, Pradip K; Dasgupta, Biplab

    2013-01-01

    Purpose Classical pharmacology allows the use and development of conventional phytomedicine faster and more economically than conventional drugs. This approach should be tested for their efficacy in terms of complementarity and disease control. The purpose of this study was to determine the molecular mechanisms by which nimbolide, a triterpenoid found in the well-known medicinal plant Azadirachta indica controls glioblastoma (GBM) growth. Experimental Design Using in vitro signaling, anchorage-independent growth, kinase assays, and xenograft models, we investigated the mechanisms of its growth inhibition in glioblastoma. Results We show that nimbolide or an ethanol soluble fraction of A. indica leaves (Azt) that contains nimbolide as the principal cytotoxic agent is highly cytotoxic against GBM in vitro and in vivo. Azt caused cell cycle arrest, most prominently at the G1-S stage in GBM cells expressing EGFRvIII, an oncogene present in about 20-25% of GBMs. Azt/nimbolide directly inhibited CDK4/CDK6 kinase activity leading to hypophosphorylation of the retinoblastoma (RB) protein, cell cycle arrest at G1-S and cell death. Independent of RB hypophosphorylation, Azt also significantly reduced proliferative and survival advantage of GBM cells in vitro and in tumor xenografts by downregulating Bcl2 and blocking growth factor induced phosphorylation of Akt, Erk1/2 and STAT3. These effects were specific since Azt did not affect mTOR or other cell cycle regulators. In vivo, Azt completely prevented initiation and inhibited progression of GBM growth. Conclusions Our preclinical findings demonstrate Nimbolide as a potent anti-glioma agent that blocks cell cycle and inhibits glioma growth in vitro and in vivo. PMID:24170547

  11. DNA-damage response gene GADD45A induces differentiation in hematopoietic stem cells without inhibiting cell cycle or survival.

    Science.gov (United States)

    Wingert, Susanne; Thalheimer, Frederic B; Haetscher, Nadine; Rehage, Maike; Schroeder, Timm; Rieger, Michael A

    2016-03-01

    Hematopoietic stem cells (HSCs) maintain blood cell production life-long by their unique abilities of self-renewal and differentiation into all blood cell lineages. Growth arrest and DNA-damage-inducible 45 alpha (GADD45A) is induced by genotoxic stress in HSCs. GADD45A has been implicated in cell cycle control, cell death and senescence, as well as in DNA-damage repair. In general, GADD45A provides cellular stability by either arresting the cell cycle progression until DNA damage is repaired or, in cases of fatal damage, by inducing apoptosis. However, the function of GADD45A in hematopoiesis remains controversial. We revealed the changes in murine HSC fate control orchestrated by the expression of GADD45A at single cell resolution. In contrast to other cellular systems, GADD45A expression did not cause a cell cycle arrest or an alteration in the decision between cell survival and apoptosis in HSCs. Strikingly, GADD45A strongly induced and accelerated the differentiation program in HSCs. Continuous tracking of individual HSCs and their progeny via time-lapse microscopy elucidated that once GADD45A was expressed, HSCs differentiate into committed progenitors within 29 hours. GADD45A-expressing HSCs failed to long-term reconstitute the blood of recipients by inducing multilineage differentiation in vivo. Importantly, γ-irradiation of HSCs induced their differentiation by upregulating endogenous GADD45A. The differentiation induction by GADD45A was transmitted by activating p38 Mitogen-activated protein kinase (MAPK) signaling and allowed the generation of megakaryocytic-erythroid, myeloid, and lymphoid lineages. These data indicate that genotoxic stress-induced GADD45A expression in HSCs prevents their fatal transformation by directing them into differentiation and thereby clearing them from the system. Stem Cells 2016;34:699-710. PMID:26731607

  12. 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...

  13. Recent progress in micromorph solar cells

    OpenAIRE

    Meier, Johannes; Dubail, S.; Cuperus, J.; Kroll, U.; Platz, R.; Torres, Pedro; Anna Selvan, J. A.; Pernet, P.; Beck, N; Pellaton Vaucher, N.; Hof, Ch.; Fischer, Diego; Keppner, Herbert; Shah, Arvind

    2008-01-01

    Recently, we have demonstrated that intrinsic hydrogenated microcrystalline silicon, as deposited by the very high frequency glow-discharge technique, can be used as the active layers of p–i–n solar cells. Our microcrystalline silicon represents a new form of thin film crystalline silicon that can be deposited (in contrast to any other approach found in literature) at substrate temperatures as low as 200°C. The combination of amorphous and microcrystalline material leads to a ‘real' silicon-b...

  14. Cell cycle dependence of mitotic delay in X-irradiated normal and ataxia-telangiectasia fibroblasts

    International Nuclear Information System (INIS)

    An investigation has been made of the relationship between suppression in the mitotic index and inhibition of DNA synthesis in normal (N) and ataxia-telangiectasia (A-T) skin fibroblasts, using tritiated thymidine as a marker of the cell cycle. The delay in progression of X-irradiated cells through the cell cycle, which is more pronounced in normal than in A-T fibroblasts, was greatest for cells in G2 at the time of irradiation. The greater effect of radiation on the initiation of DNA synthesis in N than in A-T cells was reflected in the shape of the percent labelled mitosis curves after 3H-thymidine treatment. The duration of the S phase in unirradiated A-T cells was greater than in N cells. It is pointed out that any explanation of the underlying defect in A-T must account not only for the reduced radiosensitivity of DNA synthesis but for the lesser delay in G2. The authors claim that their data support the hypothesis that DNA is the principal target for radiation-induced G2 delay. (U.K.)

  15. A New Challenge to Solar Dynamo Models from Helioseismic Observations: The Latitudinal Dependence of the Progression of the Solar Cycle

    CERN Document Server

    Simoniello, R; Jain, K; Hill, F

    2016-01-01

    The solar cycle onset at mid-latitudes, the slow down of the sunspot drift toward the equator, the tail-like attachment and the overlap of successive cycles at the time of activity minimum are delicate issues in $\\alpha\\Omega$ dynamo wave and flux transport dynamo models. Very different parameter values produce similar results, making it difficult to understand the origin of these solar cycle properties. We use GONG helioseismic data to investigate the progression of the solar cycle as observed in intermediate-degree global $p$-mode frequency shifts at different latitudes and subsurface layers, from the beginning of solar cycle 23 up to the maximum of the current solar cycle. We also analyze those for high-degree modes in each hemisphere obtained through the ring-diagram technique of local helioseismology. The analysis highlighted differences in the progression of the cycle below 15\\degr\\ compared to higher latitudes. While the cycle starts at mid-latitudes and then migrates equatorward/poleward, the sunspot ...

  16. Leg joint power output during progressive resistance FES-LCE cycling in SCI subjects: developing an index of fatigue

    OpenAIRE

    Faghri Pouran D; Haapala Stephenie A; Adams Douglas J

    2008-01-01

    Abstract Background The purpose of this study was to investigate the biomechanics of the hip, knee and ankle during a progressive resistance cycling protocol in an effort to detect and measure the presence of muscle fatigue. It was hypothesized that knee power output can be used as an indicator of fatigue in order to assess the cycling performance of SCI subjects. Methods Six spinal cord injured subjects (2 incomplete, 4 complete) between the ages of twenty and fifty years old and possessing ...

  17. Hepatocytes Polyploidization and Cell Cycle Control in Liver Physiopathology

    Directory of Open Access Journals (Sweden)

    Géraldine Gentric

    2012-01-01

    Full Text Available Most cells in mammalian tissues usually contain a diploid complement of chromosomes. However, numerous studies have demonstrated a major role of “diploid-polyploid conversion” during physiopathological processes in several tissues. In the liver parenchyma, progressive polyploidization of hepatocytes takes place during postnatal growth. Indeed, at the suckling-weaning transition, cytokinesis failure events induce the genesis of binucleated tetraploid liver cells. Insulin signalling, through regulation of the PI3K/Akt signalling pathway, is essential in the establishment of liver tetraploidization by controlling cytoskeletal organisation and consequently mitosis progression. Liver cell polyploidy is generally considered to indicate terminal differentiation and senescence, and both lead to a progressive loss of cell pluripotency associated to a markedly decreased replication capacity. Although adult liver is a quiescent organ, it retains a capacity to proliferate and to modulate its ploidy in response to various stimuli or aggression (partial hepatectomy, metabolic overload (i.e., high copper and iron hepatic levels, oxidative stress, toxic insult, and chronic hepatitis etc.. Here we review the mechanisms and functional consequences of hepatocytes polyploidization during normal and pathological liver growth.

  18. Plant characteristics of an integrated solid oxide fuel cell cycle and a steam cycle

    International Nuclear Information System (INIS)

    Plant characteristics of a system containing a solid oxide fuel cell (SOFC) cycle on the top of a Rankine cycle were investigated. A desulfurization reactor removes the sulfur content in the fuel, while a pre-reformer broke down the heavier 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 recovery steam generator (HRSG). The remaining energy of the off-gases was recycled back to the topping cycle for further utilization. Several parameter studies were carried out to investigate the sensitivity of the suggested plant. It was shown that the operation temperature of the desulfurization and the pre-reformer 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 efficiency by about 6%. An optimal plant efficiency of about 71% was achieved by optimizing the plant.

  19. 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

  20. Proanthocyanidins from the American Cranberry (Vaccinium macrocarpon Induce Cell Cycle Alterations in DU145 Human Prostate Cancer Cells in Vitro by Affecting the Expression of Cell Cycle-Associated Proteins

    Directory of Open Access Journals (Sweden)

    Joseph Kim

    2014-04-01

    Full Text Available Background: Prostate cancer is one of the most common cancers in the world. There are genetic and environmental factors that can potentially impact the development and progression of many types of cancer, including prostate cancer. As a consequence of environmental factors, such as diet having a potential effect on the development of prostate cancer, considerable interest in the possible health benefits associated with the inclusion and consumption of certain foods in the diet exists. Context and purpose of this study: This study describes the effects of a proanthocyanidinenriched fraction (PACs isolated from the American cranberry (Vaccinium macrocarpon on the behaviour of androgen-refractory (insensitive DU145 human prostate cancer cells in vitro. Results: Following treatment of DU145 human prostate cancer cells with 25 µg/mL of PACs for six hours, PACs significantly decreased the cellular viability of DU145 cells. PACs treatment (25 µg/mL for 6 hours of DU145 cells increased the proportion of cells in the G2-M phase of the cell cycle and decreased the proportion of cells in the G1 phase of the cell cycle. These alterations were associated with changes in cell cycle regulatory proteins and other cell cycle associated proteins. PACs increased the expression of cyclin E, cyclin D1, CDK2 and CDK4, and decreased the expression of cyclin A and cyclin B1. The protein expression level of p27 increased, and the protein expression levels of p16INK4a, p21, and pRBp107 decreased in response to PACs treatment. The protein expression level of pRBp130 was unchanged in Functional Foods in Health and Disease 2014; 4(2:130- 146 Page 131 of 146 response to PACs treatment. Conclusions: These findings demonstrate that proanthocyanidins from the American cranberry can affect the behaviour of human prostate cancer cells in vitro and further support the potential health benefits associated with cranberries.

  1. 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.

  2. Synadenium umbellatum Pax. promotes cell cycle arrest and induces apoptosis in K-562 leukemia cells

    Directory of Open Access Journals (Sweden)

    Mariana Flavia da Mota

    2012-09-01

    Full Text Available Chronic myeloid leukemia (CML is a clonal myeloproliferative disease that shows apoptosis resistance. The introduction of imatinib mesylate has revolutionized the treatment of CML, but imatinib resistance may develop at any time and inevitably leads to disease progression. Synadenium umbellatum Pax. belongs to the Euphorbiaceae family and is popularly used in Brazil for the treatment of cancer. The cytotoxicity of Euphorbiaceae is associated with the ability of these plants and their bioactive compounds to induce apoptotic tumor cell death. Therefore, we aimed to investigate the cytotoxicity and the mechanisms of death induced by S. umbellatum extract in leukemic cells. S. umbellatum cytotoxicity was evaluated by trypan blue exclusion assay and flow cytometric analysis of the cell cycle; the mechanisms involved in K-562 cell death were investigated by light microscopy and flow cytometry. The results demonstrate that S. umbellatum is cytotoxic to leukemic cells in a concentration-dependent manner. Morphological analysis revealed that S. umbellatum treatment induced K-562 cell death by an apoptotic pathway. Furthermore, data indicate ROS overproduction, alterations in mitochondrial membrane potential, phosphatidylserine externalization and activation of caspase 9. Taken together, the results demonstrate that S. umbellatum extract arrested the cell cycle and triggered apoptosis at several levels in K-562 cells.A leucemia mielóide crônica (LMC é uma doença mieloproliferativa clonal, que apresenta resistência à apoptose. A introdução do mesilato de imatinibe revolucionou o tratamento da LMC, porém a resistência ao imatinibe pode ser desenvolvida em qualquer tempo e, inevitavelmente, leva à progressão da doença. Synadenium umbellatum Pax. pertence à família Euphorbiaceae e é usado popularmente no Brasil para o tratamento do câncer. A citotoxicidade das Euphorbiaceae está associada com a capacidade dessas plantas e seus compostos

  3. Fascin overexpression promotes neoplastic progression in oral squamous cell carcinoma

    International Nuclear Information System (INIS)

    Fascin is a globular actin cross-linking protein, which plays a major role in forming parallel actin bundles in cell protrusions and is found to be associated with tumor cell invasion and metastasis in various type of cancers including oral squamous cell carcinoma (OSCC). Previously, we have demonstrated that fascin regulates actin polymerization and thereby promotes cell motility in K8-depleted OSCC cells. In the present study we have investigated the role of fascin in tumor progression of OSCC. To understand the role of fascin in OSCC development and/or progression, fascin was overexpressed along with vector control in OSCC derived cells AW13516. The phenotype was studied using wound healing, Boyden chamber, cell adhesion, Hanging drop, soft agar and tumorigenicity assays. Further, fascin expression was examined in human OSCC samples (N = 131) using immunohistochemistry and level of its expression was correlated with clinico-pathological parameters of the patients. Fascin overexpression in OSCC derived cells led to significant increase in cell migration, cell invasion and MMP-2 activity. In addition these cells demonstrated increased levels of phosphorylated AKT, ERK1/2 and JNK1/2. Our in vitro results were consistent with correlative studies of fascin expression with the clinico-pathological parameters of the OSCC patients. Fascin expression in OSCC showed statistically significant correlation with increased tumor stage (P = 0.041), increased lymph node metastasis (P = 0.001), less differentiation (P = 0.005), increased recurrence (P = 0.038) and shorter survival (P = 0.004) of the patients. In conclusion, our results indicate that fascin promotes tumor progression and activates AKT and MAPK pathways in OSCC-derived cells. Further, our correlative studies of fascin expression in OSCC with clinico-pathological parameters of the patients indicate that fascin may prove to be useful in prognostication and treatment of OSCC

  4. 17-Allylamino-17-demethoxygeldanamycin induces downregulation of critical Hsp90 protein clients and results in cell cycle arrest and apoptosis of human urinary bladder cancer cells

    International Nuclear Information System (INIS)

    17-Allylamino-17-demethoxygeldanamycin (17-AAG), a benzoquinone ansamycin antibiotic, specifically targets heat shock protein 90 (Hsp90) and interferes with its function as a molecular chaperone that maintains the structural and functional integrity of various protein clients involved in cellular signaling. In this study, we have investigated the effect of 17-AAG on the regulation of Hsp90-dependent signaling pathways directly implicated in cell cycle progression, survival and motility of human urinary bladder cancer cell lines. We have used MTT-based assays, FACS analysis, Western blotting, semi-quantitative RT-PCR, immunocytochemistry and scratch-wound assay in RT4, RT112 and T24 human urinary bladder cancer cell lines. We have demonstrated that, upon 17-AAG treatment, bladder cancer cells are arrested in the G1 phase of the cell cycle and eventually undergo apoptotic cell death in a dose-dependent manner. Furthermore, 17-AAG administration was shown to induce a pronounced downregulation of multiple Hsp90 protein clients and other downstream effectors, such as IGF-IR, Akt, IKK-α, IKK-β, FOXO1, ERK1/2 and c-Met, resulting in sequestration-mediated inactivation of NF-κB, reduced cell proliferation and decline of cell motility. In total, we have clearly evinced a dose-dependent and cell type-specific effect of 17-AAG on cell cycle progression, survival and motility of human bladder cancer cells, due to downregulation of multiple Hsp90 clients and subsequent disruption of signaling integrity

  5. A systematic analysis of cell cycle regulators in yeast reveals that most factors act independently of cell size to control initiation of division.

    Directory of Open Access Journals (Sweden)

    Scott A Hoose

    Full Text Available Upstream events that trigger initiation of cell division, at a point called START in yeast, determine the overall rates of cell proliferation. The identity and complete sequence of those events remain unknown. Previous studies relied mainly on cell size changes to identify systematically genes required for the timely completion of START. Here, we evaluated panels of non-essential single gene deletion strains for altered DNA content by flow cytometry. This analysis revealed that most gene deletions that altered cell cycle progression did not change cell size. Our results highlight a strong requirement for ribosomal biogenesis and protein synthesis for initiation of cell division. We also identified numerous factors that have not been previously implicated in cell cycle control mechanisms. We found that CBS, which catalyzes the synthesis of cystathionine from serine and homocysteine, advances START in two ways: by promoting cell growth, which requires CBS's catalytic activity, and by a separate function, which does not require CBS's catalytic activity. CBS defects cause disease in humans, and in animals CBS has vital, non-catalytic, unknown roles. Hence, our results may be relevant for human biology. Taken together, these findings significantly expand the range of factors required for the timely initiation of cell division. The systematic identification of non-essential regulators of cell division we describe will be a valuable resource for analysis of cell cycle progression in yeast and other organisms.

  6. Cell-cycle specific expression of a small proline-rich protein in Chinese hamster ovary cells

    International Nuclear Information System (INIS)

    Squamous metaplasia of the bronchial epithelium is generally believed to be involved in the neoplastic progression toward squamous cell carcinomas. Thus, it is important to understand the mechanisms controlling this type of differentiation. The induction of two families of cDNAs encoding a small proline-rich protein (sPRP), sprI and sprII, was first identified in human keratinocytes exhibiting squamous differentiation. cDNAs similar to sprI have also been identified in cultured tracheal epithelial cells undergoing squamous differentiation. The first step during the squamous differentiation process is the inhibition of cell growth; it has also been noted that a sPRP mRNA in Chinese hamster ovary (CHO) cells is induced 10-fold just before the cultures reach confluence. Thus, sPRP may stop cell division in cells undergoing squamous differentation. In support of this possibility are the recent investigations correlating expression of sPRP with cell morphology. Specific immunoreactivity to sPRP, using affinity-purified antibodies, showed a strong immunostaining in cells with a round configuration, while less staining was observed in other cells. The major part of the CHO population showed no immunoreactivity. One interpretation of this observation is that the expression of sPRP may be cell-cyle regulated. The purpose of this investigation was to determine the phase of the cell cycle where induced synthesis of sPRP mRNA occurs

  7. Cell Cycle Analysis of CML Stem Cells Using Hoechst 33342 and Propidium Iodide.

    Science.gov (United States)

    DeSouza, Ngoc; Zhou, Megan; Shan, Yi

    2016-01-01

    Chronic myeloid leukemia (CML) is a myeloproliferative disease with an expansion of white blood cells. The current treatments for CML are shown not to be long-term effective because of CML stem cells' insensitivity to tyrosine kinase inhibitors. Therefore, studying more about CML stem cells is essential to understand the pathways of CML stem cell development and proliferation and finally lead to effective treatments to eliminate CML stem cells and eradicate CML. This chapter describes two methods to analyze cell cycle of CML stem cells. The rare population of CML stem cells can be identified by staining with cell surface markers, and then DNA-binding dyes Hoechst 33342 and propidium iodide (PI) are added to stain the DNA content which is changed when cells go through different phases of the cell cycle. Samples are run through the flow cytometer to be analyzed based on different absorbance and emission wavelengths of different florescent colors. PMID:27581138

  8. Functional dissection of Caenorhabditis elegans CLK-2/TEL2 cell cycle defects during embryogenesis and germline development.

    Directory of Open Access Journals (Sweden)

    Sandra C Moser

    2009-04-01

    Full Text Available CLK-2/TEL2 is essential for viability from yeasts to vertebrates, but its essential functions remain ill defined. CLK-2/TEL2 was initially implicated in telomere length regulation in budding yeast, but work in Caenorhabditis elegans has uncovered a function in DNA damage response signalling. Subsequently, DNA damage signalling defects associated with CLK-2/TEL2 have been confirmed in yeast and human cells. The CLK-2/TEL2 interaction with the ATM and ATR DNA damage sensor kinases and its requirement for their stability led to the proposal that CLK-2/TEL2 mutants might phenocopy ATM and/or ATR depletion. We use C. elegans to dissect developmental and cell cycle related roles of CLK-2. Temperature sensitive (ts clk-2 mutants accumulate genomic instability and show a delay of embryonic cell cycle timing. This delay partially depends on the worm p53 homolog CEP-1 and is rescued by co-depletion of the DNA replication checkpoint proteins ATL-1 (C. elegans ATR and CHK-1. In addition, clk-2 ts mutants show a spindle orientation defect in the eight cell stages that lead to major cell fate transitions. clk-2 deletion worms progress through embryogenesis and larval development by maternal rescue but become sterile and halt germ cell cycle progression. Unlike ATL-1 depleted germ cells, clk-2-null germ cells do not accumulate DNA double-strand breaks. Rather, clk-2 mutant germ cells arrest with duplicated centrosomes but without mitotic spindles in an early prophase like stage. This germ cell cycle arrest does not depend on cep-1, the DNA replication, or the spindle checkpoint. Our analysis shows that CLK-2 depletion does not phenocopy PIKK kinase depletion. Rather, we implicate CLK-2 in multiple developmental and cell cycle related processes and show that CLK-2 and ATR have antagonising functions during early C. elegans embryonic development.

  9. Induced differentiation of cancer cells: second generation potent hybrid polar compounds target cell cycle regulators

    International Nuclear Information System (INIS)

    Hybrid polar compounds are potent inducers of differentiation of a wide variety of cancer transformed cells. Hexamethylene bisacetamide (HMBA) has been used as a prototype of these compounds to investigate their mechanism of action. Employing murine erythroleukemia (MEL) cells as a model, three characteristics of inducer-mediated commitment to terminal differentiation were demonstrated: (I) induced commitment was stochastic, requiring up to 5 cell cycles to recruit essentially all cells to commit to growth arrest in G1; (II) inducers caused a prolongation of the initial G1; and (III) the hybrid polar compounds induced a wide variety of transformed cells to terminal differentiation. These findings suggested that the rate limiting factor or factors for induction by these agents may be at the level of protein(s) regulating G1-to-S progression, which are common to most eukaryotic cells. It was found that HMBA induced a profound suppression of cyclin dependent kinase, cdk4, which reflected a marked decrease in stability of the protein, and is a critical change in the pathway of induced differentiation. HMBA also induced an increase in pRB and in the active, underphosphorylated form of this protein, an increase in the pRB related protein, p107, and an increase in the cyclin dependent kinase inhibitor, p21. Further, the free form of the transcription factor, E2F, was markedly decreased within hours of exposure of transformed cells to HMBA and found to complex with p107 and cdk 2. A phase II clinical trial was conducted using HMBA to treat patients with myelodysplastic syndrome (MDS) or acute myelogenous leukemia. Of 28 patients, 9 patients achieved a complete or partial remission lasting from 1 to 16 months. These clinical studies also provided direct evidence that HMBA induces differentiation of transformed cells in patients. In four separate courses of treatment with HMBA, a patient with MDS and the monosomy 7 karyotype marking the malignant clone of bone marrow blast

  10. Quantifying the length and variance of the eukaryotic cell cycle phases by a stochastic model and dual nucleoside pulse labelling.

    Directory of Open Access Journals (Sweden)

    Tom Serge Weber

    2014-07-01

    Full Text Available A fundamental property of cell populations is their growth rate as well as the time needed for cell division and its variance. The eukaryotic cell cycle progresses in an ordered sequence through the phases G1, S, G2, and M, and is regulated by environmental cues and by intracellular checkpoints. Reflecting this regulatory complexity, the length of each phase varies considerably in different kinds of cells but also among genetically and morphologically indistinguishable cells. This article addresses the question of how to describe and quantify the mean and variance of the cell cycle phase lengths. A phase-resolved cell cycle model is introduced assuming that phase completion times are distributed as delayed exponential functions, capturing the observations that each realization of a cycle phase is variable in length and requires a minimal time. In this model, the total cell cycle length is distributed as a delayed hypoexponential function that closely reproduces empirical distributions. Analytic solutions are derived for the proportions of cells in each cycle phase in a population growing under balanced growth and under specific non-stationary conditions. These solutions are then adapted to describe conventional cell cycle kinetic assays based on pulse labelling with nucleoside analogs. The model fits well to data obtained with two distinct proliferating cell lines labelled with a single bromodeoxiuridine pulse. However, whereas mean lengths are precisely estimated for all phases, the respective variances remain uncertain. To overcome this limitation, a redesigned experimental protocol is derived and validated in silico. The novelty is the timing of two consecutive pulses with distinct nucleosides that enables accurate and precise estimation of both the mean and the variance of the length of all phases. The proposed methodology to quantify the phase length distributions gives results potentially equivalent to those obtained with modern phase

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

    DEFF Research Database (Denmark)

    Rokni, Masoud

    2010-01-01

    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......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...... 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....

  12. 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

    , 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......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...

  13. Does Arabidopsis thaliana DREAM of cell cycle control?

    Science.gov (United States)

    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 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. PMID:26089020

  14. Cell cycle arrest induced by MPPa-PDT in MDA-MB-231 cells

    Science.gov (United States)

    Liang, Liming; Bi, Wenxiang; Tian, Yuanyuan

    2016-05-01

    Photodynamic therapy (PDT) is a medical treatment using a photosensitizing agent and light source to treat cancers. Pyropheophorbidea methyl ester (MPPa), a derivative of chlorophyll, is a novel potent photosensitizer. To learn more about this photosensitizer, we examined the cell cycle arrest in MDA-MB-231. Cell cycle and apoptosis were measured by flow cytometer. Checkpoints of the cell cycle were measured by western blot. In this study, we found that the expression of Cyclin D1 was obviously decreased, while the expression of Chk2 and P21 was increased after PDT treatment. This study showed that MPPa-PDT affected the checkpoints of the cell cycle and led the cells to apoptosis.

  15. Do progressive goverments undertake different debt burdens? Partisan vs. electoral cycles

    Directory of Open Access Journals (Sweden)

    I.M. García-Sánchez

    2011-06-01

    Full Text Available Public debt has traditionally been explained mainly by two political factors: a progressive ideology and the electoral cycle. The aim of this paper is to demonstrate how these two factors influence the behavior of Spanish local governments as regards indebtedness, and also how indebtedness is influenced by the interaction of ideology and the electoral cycle.Different dependence models were estimated using panel data methodology based on a sample comprised of Spanish provincial capitals and towns with populations over 50,000, for a total of 148 town councils. The time frame corresponds to the fiscal years 1988 to 2008, inclusive. The results show that in an electoral year all politicians behave opportunistically, giving rise to an important increase in public debt in relation to municipal revenue, although progressive incumbents incur three times more debt than those of the opposite ideology. Moreover, the presence of conservative parties in government has tended to significantly attenuate this behavior in years prior to elections, whereas progressive or left-wing parties have not. It must also be noted that partisan and electoral business cycles have been mitigated since 2002, when the Budgetary Stability Law came into effect, imposing limits on the debt of subnational administrations.The empirical evidence obtained points to the need to perfect internal and external control mechanisms in order to avoid a breakdown in the stability policy and the risk of debt becoming untenable, thus achieving greater budgetary discipline.RESUMENEl nivel de endeudamiento público ha sido explicado mediante dos factores políticos, principalmente, la ideología progresista y el ciclo electoral. El objetivo de este trabajo es evidenciar como influyen ambos factores en el comportamiento de los municipios españoles en relación con la deuda que estos asumen dada su capacidad, y como este esfuerzo se ve influenciado por la interacción entre los ciclos partidista y

  16. EFFECT OF CIS-9, TRANS-11-CONJUGATED LINOLEIC ACID ON CELL CYCLE OF MAMMARY ADENOCARCINOMA CELLS(MCF-7)

    Institute of Scientific and Technical Information of China (English)

    刘家仁; 陈炳卿; 韩晓辉; 杨艳梅; 郑玉梅; 刘瑞海

    2002-01-01

    Objective: To determine the effect of cis-9, trans-1 1-conjugated linoleic acid on the cell cycle of mammary cancer cells (MCF-7) and the possible mechanism of the inhibitory effect of c9,t11-CLA. Methods: Using cell culture and immunocytochemical techniques, we examined the cell growth, DNA synthesis, expression of PCNA , cyclin A, B1, D1, p16ink4a and p21cip/waf1 of MCF-7 cells at various c9,t11-CLA concentrations (25μM, 50μM, 100μM and 200μM), at 24h and 48h. 96% ethand was used as negative control. Results: The cell growth and DNA synthesis of MCF-7 cells were inhibited by c9,t11-CLA. After treatment with various doses of c9,t11-CLA mentioned above for 8 days, the inhibition frequency was 27.18%, 35.43%, 91.05%, and 92.86%, respectively. Inhibitory effect of c9,t11-CLA on DNA synthesis (except for 25μM, 24h) was demonstrated by significantly less incorporation of 3H-TdR than the negative control (P<0.05 and P<0.01). To further investigate the influence of the cell cycle progression, we found that c9,t11-CLA may arrest the cell cycle of MCF-7 cells. Immunocytochemical staining demonstrated that incubation with different concentration of c9,t11-CLA at various times significantly decreased the expression of PCNA, Cyclin A, B1, D1 in MCF-7 cells compared to the negative control (P<0.01), whereas the expression of p16ink4a and p21cip/waf1, cyclin-dependent kinases inhibitors (CDKI), were increased. Conclusions: The cell growth and proliferation of MCF-7 cells is inhibited by c9,t11-CLA via blocking cell cycle, accompanying reduced expression of cyclin A, B1, D1 and enhanced expression of CDKI (p16ink4a and p21cip/wafl).

  17. Innate Lymphoid Cells: Roles In Tumour Genesis And Progression

    OpenAIRE

    Jovanovic Ivan; Gajovic Nevena; Radosavljevic Gordana; Pantic Jelena; Pejnovic Nada; Arsenijevic Nebojsa; Lukic Miodrag L.

    2015-01-01

    Innate lymphoid cells (ILCs) represent the most recently identified members of the innate immune system. These cells play important roles in inflammation, tissue remodelling and metabolic disease. ILCs can be subdivided into three major groups according to their cytokine production. The role of ILCs in tumourigenesis and tumour progression is not completely clarified. In this review, we discuss whether and how ILCs are involved in tumour genesis, growth and metastasis.

  18. Innate Lymphoid Cells: Roles In Tumour Genesis And Progression

    Directory of Open Access Journals (Sweden)

    Jovanovic Ivan

    2015-06-01

    Full Text Available Innate lymphoid cells (ILCs represent the most recently identified members of the innate immune system. These cells play important roles in inflammation, tissue remodelling and metabolic disease. ILCs can be subdivided into three major groups according to their cytokine production. The role of ILCs in tumourigenesis and tumour progression is not completely clarified. In this review, we discuss whether and how ILCs are involved in tumour genesis, growth and metastasis.

  19. The circadian clock and cell cycle: Interconnected biological circuits

    OpenAIRE

    Masri, Selma; Cervantes, Marlene; Sassone-Corsi, Paolo

    2013-01-01

    The circadian clock governs biological timekeeping on a systemic level, helping to regulate and maintain physiological processes, including endocrine and metabolic pathways with a periodicity of 24-hours. Disruption within the circadian clock machinery has been linked to numerous pathological conditions, including cancer, suggesting that clock-dependent regulation of the cell cycle is an essential control mechanism. This review will highlight recent advances on the ‘gating’ controls of the ci...

  20. TRICHOSTATIN A INHIBITS PROLIFERATION, INDUCES APOPTOSIS AND CELL CYCLE ARREST IN HELA CELLS

    Institute of Scientific and Technical Information of China (English)

    XU Zhou-min; WANG Yi-qun; MEI Qi; CHEN Jian; DU Jia; WEI Yan; XU Ying-chun

    2006-01-01

    Objective: The histone deacetylase inhibitors (HDACIS) have been shown to inhibit cancer cell proliferation, stimulate apoptosis, an induce cell cycle arrest. Our purpose was to investigate the antiproliferative effects of a HDACI, trichostatin A (TSA), against human cervical cancer cells (HeLa). Methods: HeLa cells were treated in vitro with various concentrations of TSA. The inhibitory effect of TSA on the growth of HeLa cells was measured by MTT assay. To detect the characteristic of apoptosis chromatin condensation, HeLa cells were stained with Hoechst 33258 in the presence of TSA. Induction of cell cycle arrest was studied by flow cytometry. Changes in gene expression of p53, p21Waf1 and p27Kip1 were studied by semiquantitative RT-PCR. Results: TSA inhibited cell growth in a time- and dose-dependent manner. Hoechst 33258 staining assay showed that TSA induced apoptosis. Cell cycle analysis indicated that treatment with TSA decreased the proportion of cells in S phase and increased the proportion of cells in G0/G1 and/or G2/M phases of the cell cycle. This was concomitant with overexpression of genes related to malignant phenotype, including an increase in p53, p21Waf1 and p27Kip1. Conclusion: These results suggest that TSA is effective in inhibiting growth of HeLa cells in vitro. The findings raise the possibility that TSA may prove particularly effective in treatment of cervical cancers.

  1. 2011 Annual Progress Report: DOE Hydrogen and Fuel Cells Program

    Energy Technology Data Exchange (ETDEWEB)

    Satyapal, Sunita [Office of Energy Efficiency and Renewable Energy (EERE), Washington, DC (United States)

    2011-11-01

    The 2011 Annual Progress Report summarizes fiscal year 2011 activities and accomplishments by projects funded by the DOE Hydrogen Program. It covers the program areas of hydrogen production and delivery; hydrogen storage; fuel cells; manufacturing; technology validation; safety, codes and standards; education; market transformation; and systems analysis.

  2. 2014 Annual Progress Report: DOE Hydrogen and Fuel Cells Program

    Energy Technology Data Exchange (ETDEWEB)

    none,

    2014-11-01

    The 2014 Annual Progress Report summarizes fiscal year 2014 activities and accomplishments by projects funded by the DOE Hydrogen Program. It covers the program areas of hydrogen production and delivery; hydrogen storage; fuel cells; manufacturing; technology validation; safety, codes and standards; market transformation; and systems analysis.

  3. 2013 Annual Progress Report: DOE Hydrogen and Fuel Cells Program

    Energy Technology Data Exchange (ETDEWEB)

    none,

    2013-12-01

    The 2013 Annual Progress Report summarizes fiscal year 2013 activities and accomplishments by projects funded by the DOE Hydrogen Program. It covers the program areas of hydrogen production and delivery; hydrogen storage; fuel cells; manufacturing; technology validation; safety, codes and standards; market transformation; and systems analysis.

  4. Stochastic Polynomial Dynamic Models of the Yeast Cell Cycle

    Science.gov (United States)

    Mitra, Indranil; Dimitrova, Elena; Jarrah, Abdul S.

    2010-03-01

    In the last decade a new holistic approach for tackling biological problems, systems biology, which takes into account the study of the interactions between the components of a biological system to predict function and behavior has emerged. The reverse-engineering of biochemical networks from experimental data have increasingly become important in systems biology. Based on Boolean networks, we propose a time-discrete stochastic framework for the reverse engineering of the yeast cell cycle regulatory network from experimental data. With a suitable choice of state set, we have used powerful tools from computational algebra, that underlie the reverse-engineering algorithm, avoiding costly enumeration strategies. Stochasticity is introduced by choosing at each update step a random coordinate function for each variable, chosen from a probability space of update functions. The algorithm is based on a combinatorial structure known as the Gr"obner fans of a polynomial ideal which identifies the underlying network structure and dynamics. The model depicts a correct dynamics of the yeast cell cycle network and reproduces the time sequence of expression patterns along the biological cell cycle. Our findings indicate that the methodolgy has high chance of success when applied to large and complex systems to determine the dynamical properties of corresponding networks.

  5. 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

    2016-01-01

    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. PMID:27180572

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

    Directory of Open Access Journals (Sweden)

    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. Two parametric cell cycle analyses of plant cell suspension cultures with fragile, isolated nuclei to investigate heterogeneity in growth of batch cultivations.

    Science.gov (United States)

    Haas, Christiane; Hegner, Richard; Helbig, Karsten; Bartels, Kristin; Bley, Thomas; Weber, Jost

    2016-06-01

    Plant cell suspensions are frequently considered to be heterogeneous with respect to growth in terms of progression of the cells through the cell cycle and biomass accumulation. Thus, segregated data of fractions in different cycle phases during cultivation is needed to develop robust production processes. Bromodeoxyuridine (BrdU) incorporation and BrdU-antibodies or 5-ethynyl-2'-deoxyuridine (EdU) click-it chemistry are frequently used to acquire such information. However, their use requires centrifugation steps that cannot be readily applied to sensitive cells, particularly if nuclei have to be extracted from the protective cellular milieu and envelopes for DNA analysis. Therefore, we have established a BrdU-Hoechst stain quenching protocol for analyzing nuclei directly isolated from delicate plant cell suspension cultures. After adding BrdU to test Harpagophytum procumbens cell suspension cultures the cell cycle distribution could be adequately resolved using its incorporation for the following 72 h (after which BrdU slowed biomass accumulation). Despite this limitation, the protocol allows resolution of the cell cycle distribution of cultures that cannot be analyzed using commonly applied methods due to the cells' fragility. The presented protocol enabled analysis of cycling heterogeneities in H. procumbens batch cultivations, and thus should facilitate process control of secondary metabolite production from fragile plant in vitro cultures. Biotechnol. Bioeng. 2016;113: 1244-1250. © 2015 Wiley Periodicals, Inc. PMID:26614913

  8. SHP1-mediated cell cycle redistribution inhibits radiosensitivity of non-small cell lung cancer

    International Nuclear Information System (INIS)

    Radioresistance is the common cause for radiotherapy failure in non-small cell lung cancer (NSCLC), and the degree of radiosensitivity of tumor cells is different during different cell cycle phases. The objective of the present study was to investigate the effects of cell cycle redistribution in the establishment of radioresistance in NSCLC, as well as the signaling pathway of SH2 containing Tyrosine Phosphatase (SHP1). A NSCLC subtype cell line, radioresistant A549 (A549S1), was induced by high-dose hypofractionated ionizing radiations. Radiosensitivity-related parameters, cell cycle distribution and expression of cell cycle-related proteins and SHP1 were investigated. siRNA was designed to down-regulate SHP1expression. Compared with native A549 cells, the proportion of cells in the S phase was increased, and cells in the G0/G1 phase were consequently decreased, however, the proportion of cells in the G2/M phase did not change in A549S1 cells. Moreover, the expression of SHP1, CDK4 and CylinD1 were significantly increased, while p16 was significantly down-regulated in A549S1 cells compared with native A549 cells. Furthermore, inhibition of SHP1 by siRNA increased the radiosensitivity of A549S1 cells, induced a G0/G1 phase arrest, down-regulated CDK4 and CylinD1expressions, and up-regulated p16 expression. SHP1 decreases the radiosensitivity of NSCLC cells through affecting cell cycle distribution. This finding could unravel the molecular mechanism involved in NSCLC radioresistance

  9. A genetic interaction map of cell cycle regulators.

    Science.gov (United States)

    Billmann, Maximilian; Horn, Thomas; Fischer, Bernd; Sandmann, Thomas; Huber, Wolfgang; Boutros, Michael

    2016-04-15

    Cell-based RNA interference (RNAi) is a powerful approach to screen for modulators of many cellular processes. However, resulting candidate gene lists from cell-based assays comprise diverse effectors, both direct and indirect, and further dissecting their functions can be challenging. Here we screened a genome-wide RNAi library for modulators of mitosis and cytokinesis inDrosophilaS2 cells. The screen identified many previously known genes as well as modulators that have previously not been connected to cell cycle control. We then characterized ∼300 candidate modifiers further by genetic interaction analysis using double RNAi and a multiparametric, imaging-based assay. We found that analyzing cell cycle-relevant phenotypes increased the sensitivity for associating novel gene function. Genetic interaction maps based on mitotic index and nuclear size grouped candidates into known regulatory complexes of mitosis or cytokinesis, respectively, and predicted previously uncharacterized components of known processes. For example, we confirmed a role for theDrosophilaCCR4 mRNA processing complex componentl(2)NC136during the mitotic exit. Our results show that the combination of genome-scale RNAi screening and genetic interaction analysis using process-directed phenotypes provides a powerful two-step approach to assigning components to specific pathways and complexes. PMID:26912791

  10. Human cytochrome c enters murine J774 cells and causes G1 and G2/M cell cycle arrest and induction of apoptosis

    International Nuclear Information System (INIS)

    Cytochrome c is well known as a carrier of electrons during respiration. Current evidence indicates that cytochrome c also functions as a major component of apoptosomes to induce apoptosis in eukaryotic cells as well as an antioxidant. More recently, a prokaryotic cytochrome c, cytochrome c 551 from Pseudomonas aeruginosa, has been shown to enter in mammalian cells such as the murine macrophage-like J774 cells and causes inhibition of cell cycle progression. Much less is known about such functions by mammalian cytochromes c, particularly the human cytochrome c. We now report that similar to P. aeruginosa cytochrome c 551, the purified human cytochrome c protein can enter J774 cells and induce cell cycle arrest at the G1 to S phase, as well as at the G2/M phase at higher concentrations. Unlike P. aeruginosa cytochrome c 551 which had no effect on the induction of apoptosis, human cytochrome c induces significant apoptosis and cell death in J774 cells, presumably through inhibition of the cell cycle at the G2/M phase. When incubated with human breast cancer MCF-7 and normal mammary epithelial cell line MCF-10A1 cells, human cytochrome c entered in both types of cells but induced cell death only in the normal MCF-10A1 cells. The ability of human cytochrome c to enter J774 cells was greatly reduced at 4 deg. C, suggesting energy requirement in the entry process

  11. Piperlongumine Suppresses Proliferation of Human Oral Squamous Cell Carcinoma through Cell Cycle Arrest, Apoptosis and Senescence

    OpenAIRE

    San-Yuan Chen; Geng-Hung Liu; Wen-Ying Chao; Chung-Sheng Shi; Ching-Yen Lin; Yun-Ping Lim; Chieh-Hsiang Lu; Peng-Yeh Lai; Hau-Ren Chen; Ying-Ray Lee

    2016-01-01

    Oral squamous cell carcinoma (OSCC), an aggressive cancer originating in the oral cavity, is one of the leading causes of cancer deaths in males worldwide. This study investigated the antitumor activity and mechanisms of piperlongumine (PL), a natural compound isolated from Piper longum L., in human OSCC cells. The effects of PL on cell proliferation, the cell cycle, apoptosis, senescence and reactive oxygen species (ROS) levels in human OSCC cells were investigated. PL effectively inhibited ...

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

    Science.gov (United States)

    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. PMID:19622233

  13. Expression of survivin, a novel apoptosis inhibitor and cell cycle regulatory protein, in human gliomas

    Institute of Scientific and Technical Information of China (English)

    焦保华; 姚志刚; 耿少梅; 左书浩

    2004-01-01

    @@ Recently, a novel anti-apoptosis gene, named survivin,was identified as a structurally unique member of the inhibitor of apoptosis protein (lAP) family. The gene is located on chromosome 17q25. Survivin is a 16.5 kDa protein that is expressed in vivo in common human cancers, but not in normal adjacent tissue,1 during the G2/M phase of the cell cycle. Survivin expression is turned off during fetal development and not found in nonneoplastic adult human tissue, and it is turned on in most common human cancers. We investigated the expression of survivin in 50 patients with human gliomas, and determined its association with cell apoptosis and cell proliferation, and its impact on tumor progression and prognosis.

  14. Endothelial adhesion of synchronized gastric tumor cells changes during cell cycle transit and correlates with the expression level of CD44 splice variants

    Institute of Scientific and Technical Information of China (English)

    Anton Oertl; Jens Castein; Tobias Engl; Wolf-Dietrich Beecken; Dietger Jonas; Richard Melamed; Roman A. Blaheta

    2005-01-01

    AIM: To study adhesion capacity and CD44 expression of human gastric adenocarcinoma MKN45 cells at different stages of a first cell cycle.METHODS: MKN45 cells were synchronized by aphidicolin and assayed for adhesion to an endothelial cell (HUVEC)monolayer. Surface expression of CD44 and CD44 splice variants on MKN45 cells was evaluated by flow cytometry.Functional relevance of CD44 adhesion receptors was investigated by blocking studies using anti CD44 monoclonal antibodies or by hyaluronan digestion.RESULTS: Adhesion of MKN45 to HUVEC was increased during G2/M transit, after which adhesion returned to baseline levels with cell cycle completion. In parallel, CD44splice variants CD44v4, CD44v5, and CD44v7 were all upregulated on MKN45 during cell cycle progression with a maximum effect in G2/M. The function of CD44 surface receptors was assessed with specific receptor blocking monodonal antibodies or removal of hyaluronan by digestion with hyaluronidase. Both strategies inhibited tumor cell adhesion to HUVEC by nearly 50%, which indicates that MKN45-HUVEC-interaction is CD44 dependent.CONCLUSION: CD44 expression level is linked to the cell cycle in gastrointestinal tumor cells, which in turn leads to cell cyde dependent alterations of their adhesion behaviour to endothelium.

  15. The Manuel Lujan Jr. Neutron Scattering Center (LANSCE) experiment reports 1993 run cycle. Progress report

    Energy Technology Data Exchange (ETDEWEB)

    Farrer, R.; Longshore, A. [comps.

    1995-06-01

    This year the Manuel Lujan Jr. Neutron Scattering Center (LANSCE) ran an informal user program because the US Department of Energy planned to close LANSCE in FY1994. As a result, an advisory committee recommended that LANSCE scientists and their collaborators complete work in progress. At LANSCE, neutrons are produced by spallation when a pulsed, 800-MeV proton beam impinges on a tungsten target. The proton pulses are provided by the Clinton P. Anderson Meson Physics Facility (LAMPF) accelerator and a associated Proton Storage Ring (PSR), which can Iter the intensity, time structure, and repetition rate of the pulses. The LAMPF protons of Line D are shared between the LANSCE target and the Weapons Neutron Research (WNR) facility, which results in LANSCE spectrometers being available to external users for unclassified research about 80% of each annual LAMPF run cycle. Measurements of interest to the Los Alamos National Laboratory (LANL) may also be performed and may occupy up to an additional 20% of the available beam time. These experiments are reviewed by an internal program advisory committee. This year, a total of 127 proposals were submitted. The proposed experiments involved 229 scientists, 57 of whom visited LANSCE to participate in measurements. In addition, 3 (nuclear physics) participating research teams, comprising 44 scientists, carried out experiments at LANSCE. Instrument beam time was again oversubscribed, with 552 total days requested an 473 available for allocation.

  16. The Manuel Lujan Jr. Neutron Scattering Center (LANSCE) experiment reports 1993 run cycle. Progress report

    International Nuclear Information System (INIS)

    This year the Manuel Lujan Jr. Neutron Scattering Center (LANSCE) ran an informal user program because the US Department of Energy planned to close LANSCE in FY1994. As a result, an advisory committee recommended that LANSCE scientists and their collaborators complete work in progress. At LANSCE, neutrons are produced by spallation when a pulsed, 800-MeV proton beam impinges on a tungsten target. The proton pulses are provided by the Clinton P. Anderson Meson Physics Facility (LAMPF) accelerator and a associated Proton Storage Ring (PSR), which can Iter the intensity, time structure, and repetition rate of the pulses. The LAMPF protons of Line D are shared between the LANSCE target and the Weapons Neutron Research (WNR) facility, which results in LANSCE spectrometers being available to external users for unclassified research about 80% of each annual LAMPF run cycle. Measurements of interest to the Los Alamos National Laboratory (LANL) may also be performed and may occupy up to an additional 20% of the available beam time. These experiments are reviewed by an internal program advisory committee. This year, a total of 127 proposals were submitted. The proposed experiments involved 229 scientists, 57 of whom visited LANSCE to participate in measurements. In addition, 3 (nuclear physics) participating research teams, comprising 44 scientists, carried out experiments at LANSCE. Instrument beam time was again oversubscribed, with 552 total days requested an 473 available for allocation

  17. Amorphous silicon materials and solar cells - Progress and directions

    Science.gov (United States)

    Sabisky, E.; Mahan, H.; McMahon, T.

    In 1978, the U.S. Department of Energy initiated government sponsored research in amorphous materials and thin film solar cells. The program was subsequently transferred to the Solar Energy Research Institute for program management. The program grew into a major program for the development of high efficiency (greater than 10 percent), cost effective (15-40 cents per peak watt) thin film amorphous solar cells. The present international interest, the substantial progress made in the device area (2 percent PIN cell in 1976 to 10 percent PIN cell in 1982), and the marketing of the first consumer products using thin film solar cells are to a large ducts using thin film solar cells are to a large extent a consequence of this goal-oriented program.

  18. Mesenchymal stem cells in diabetes treatment: progress and perspectives

    Directory of Open Access Journals (Sweden)

    Yu CHENG

    2016-08-01

    Full Text Available Diabetes is a chronic metabolic disorder caused by relative or absolute insulin deficient or reduced sensitivity of target cells to insulin. Mesenchymal stem cells (MSCs are adult stem cells with multiple differentiation potential, self-renewable and immunoregulatory properties. Accumulating evidences from clinic or animal experiments recent years showed that MSCs infusion could ameliorate hyperglycemia in diabetes. The research progress of MSCs in diabetes treatment is summarized and a corresponding perspective is herewith proposed in present paper. DOI: 10.11855/j.issn.0577-7402.2016.07.16

  19. Comprehensive expression profiling of tumor cell lines identifies molecular signatures of melanoma progression.

    Directory of Open Access Journals (Sweden)

    Byungwoo Ryu

    Full Text Available BACKGROUND: Gene expression profiling has revolutionized our ability to molecularly classify primary human tumors and significantly enhanced the development of novel tumor markers and therapies; however, progress in the diagnosis and treatment of melanoma over the past 3 decades has been limited, and there is currently no approved therapy that significantly extends lifespan in patients with advanced disease. Profiling studies of melanoma to date have been inconsistent due to the heterogeneous nature of this malignancy and the limited availability of informative tissue specimens from early stages of disease. METHODOLOGY/PRINCIPLE FINDINGS: In order to gain an improved understanding of the molecular basis of melanoma progression, we have compared gene expression profiles from a series of melanoma cell lines representing discrete stages of malignant progression that recapitulate critical characteristics of the primary lesions from which they were derived. Here we describe the unsupervised hierarchical clustering of profiling data from melanoma cell lines and melanocytes. This clustering identifies two distinctive molecular subclasses of melanoma segregating aggressive metastatic tumor cell lines from less-aggressive primary tumor cell lines. Further analysis of expression signatures associated with melanoma progression using functional annotations categorized these transcripts into three classes of genes: 1 Upregulation of activators of cell cycle progression, DNA replication and repair (CDCA2, NCAPH, NCAPG, NCAPG2, PBK, NUSAP1, BIRC5, ESCO2, HELLS, MELK, GINS1, GINS4, RAD54L, TYMS, and DHFR, 2 Loss of genes associated with cellular adhesion and melanocyte differentiation (CDH3, CDH1, c-KIT, PAX3, CITED1/MSG-1, TYR, MELANA, MC1R, and OCA2, 3 Upregulation of genes associated with resistance to apoptosis (BIRC5/survivin. While these broad classes of transcripts have previously been implicated in the progression of melanoma and other malignancies, the

  20. Reliability of transcriptional cycles and the yeast cell-cycle oscillator.

    Directory of Open Access Journals (Sweden)

    Volkan Sevim

    Full Text Available A recently published transcriptional oscillator associated with the yeast cell cycle provides clues and raises questions about the mechanisms underlying autonomous cyclic processes in cells. Unlike other biological and synthetic oscillatory networks in the literature, this one does not seem to rely on a constitutive signal or positive auto-regulation, but rather to operate through stable transmission of a pulse on a slow positive feedback loop that determines its period. We construct a continuous-time Boolean model of this network, which permits the modeling of noise through small fluctuations in the timing of events, and show that it can sustain stable oscillations. Analysis of simpler network models shows how a few building blocks can be arranged to provide stability against fluctuations. Our findings suggest that the transcriptional oscillator in yeast belongs to a new class of biological oscillators.

  1. Reliability of transcriptional cycles and the yeast cell-cycle oscillator.

    Science.gov (United States)

    Sevim, Volkan; Gong, Xinwei; Socolar, Joshua E S

    2010-01-01

    A recently published transcriptional oscillator associated with the yeast cell cycle provides clues and raises questions about the mechanisms underlying autonomous cyclic processes in cells. Unlike other biological and synthetic oscillatory networks in the literature, this one does not seem to rely on a constitutive signal or positive auto-regulation, but rather to operate through stable transmission of a pulse on a slow positive feedback loop that determines its period. We construct a continuous-time Boolean model of this network, which permits the modeling of noise through small fluctuations in the timing of events, and show that it can sustain stable oscillations. Analysis of simpler network models shows how a few building blocks can be arranged to provide stability against fluctuations. Our findings suggest that the transcriptional oscillator in yeast belongs to a new class of biological oscillators. PMID:20628620