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Sample records for cell cycle pathways

  1. Backup pathways of NHEJ in cells of higher eukaryotes: Cell cycle dependence

    International Nuclear Information System (INIS)

    DNA double-strand breaks (DSBs) induced by ionizing radiation (IR) in cells of higher eukaryotes are predominantly repaired by a pathway of non-homologous end joining (NHEJ) utilizing Ku, DNA-PKcs, DNA ligase IV, XRCC4 and XLF/Cernunnos (D-NHEJ) as central components. Work carried out in our laboratory and elsewhere shows that when this pathway is chemically or genetically compromised, cells do not shunt DSBs to homologous recombination repair (HRR) but instead use another form of NHEJ operating as a backup (B-NHEJ). Here I review our efforts to characterize this repair pathway and discuss its dependence on the cell cycle as well as on the growth conditions. I present evidence that B-NHEJ utilizes ligase III, PARP-1 and histone H1. When B-NHEJ is examined throughout the cell cycle, significantly higher activity is observed in G2 phase that cannot be attributed to HRR. Furthermore, the activity of B-NHEJ is compromised when cells enter the plateau phase of growth. Together, these observations uncover a repair pathway with unexpected biochemical constitution and interesting cell cycle and growth factor regulation. They generate a framework for investigating the mechanistic basis of HRR contribution to DSB repair.

  2. Backup pathways of NHEJ in cells of higher eukaryotes: cell cycle dependence.

    Science.gov (United States)

    Iliakis, George

    2009-09-01

    DNA double-strand breaks (DSBs) induced by ionizing radiation (IR) in cells of higher eukaryotes are predominantly repaired by a pathway of non-homologous end joining (NHEJ) utilizing Ku, DNA-PKcs, DNA ligase IV, XRCC4 and XLF/Cernunnos (D-NHEJ) as central components. Work carried out in our laboratory and elsewhere shows that when this pathway is chemically or genetically compromised, cells do not shunt DSBs to homologous recombination repair (HRR) but instead use another form of NHEJ operating as a backup (B-NHEJ). Here I review our efforts to characterize this repair pathway and discuss its dependence on the cell cycle as well as on the growth conditions. I present evidence that B-NHEJ utilizes ligase III, PARP-1 and histone H1. When B-NHEJ is examined throughout the cell cycle, significantly higher activity is observed in G2 phase that cannot be attributed to HRR. Furthermore, the activity of B-NHEJ is compromised when cells enter the plateau phase of growth. Together, these observations uncover a repair pathway with unexpected biochemical constitution and interesting cell cycle and growth factor regulation. They generate a framework for investigating the mechanistic basis of HRR contribution to DSB repair. PMID:19604590

  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. 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

  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. Oridonin induces apoptosis and cell cycle arrest of gallbladder cancer cells via the mitochondrial pathway

    International Nuclear Information System (INIS)

    Gallbladder cancer is the most frequent malignancy of the bile duct with high aggressive and extremely poor prognosis. The main objective of the paper was to investigate the inhibitory effects of oridonin, a diterpenoid isolated from Rabdosia rubescens, on gallbladder cancer both in vitro and in vivo and to explore the mechanisms underlying oridonin-induced apoptosis and cell cycle arrest. The anti-tumor activity of oridonin on SGC996 and NOZ cells was assessed by the MTT and colony forming assays. Cell cycle changes were detected by flow cytometric analysis. Apoptosis was detected by annexin V/PI double-staining and Hoechst 33342 staining assays. Loss of mitochondrial membrane potential was observed by Rhodamine 123 staining. The in vivo efficacy of oridonin was evaluated using a NOZ xenograft model in athymic nude mice. The expression of cell cycle- and apoptosis-related proteins in vitro and in vivo was analyzed by western blot analysis. Activation of caspases (caspase-3, -8 and -9) was measured by caspases activity assay. Oridonin induced potent growth inhibition, S-phase arrest, apoptosis, and colony-forming inhibition in SGC996 and NOZ cells in a dose-dependent manner. Intraperitoneal injection of oridonin (5, 10, or 15 mg/kg) for 3 weeks significantly inhibited the growth of NOZ xenografts in athymic nude mice. We demonstrated that oridonin regulated cell cycle-related proteins in response to S-phase arrest by western blot analysis. In contrast, we observed inhibition of NF-κB nuclear translocation and an increase Bax/Bcl-2 ratio accompanied by activated caspase-3, caspase-9 and PARP-1 cleavage after treatment with oridonin, which indicate that the mitochondrial pathway is involved in oridonin-mediated apoptosis. Oridonin possesses potent anti-gallbladder cancer activities that correlate with regulation of the mitochondrial pathway, which is critical for apoptosis and S-phase arrest. Therefore, oridonin has potential as a novel anti-tumor therapy for the

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

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    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.

  8. Respiratory syncytial virus matrix protein induces lung epithelial cell cycle arrest through a p53 dependent pathway.

    Science.gov (United States)

    Bian, Tao; Gibbs, John D; Örvell, Claes; Imani, Farhad

    2012-01-01

    Respiratory syncytial virus (RSV) is the major cause of viral respiratory infections in children. Our previous study showed that the RSV infection induced lung epithelial cell cycle arrest, which enhanced virus replication. To address the mechanism of RSV-induced cell cycle arrest, we examined the contribution of RSV-matrix (RSV-M) protein. In this report, we show that in both the A549 cell line and primary human bronchial epithelial (PHBE) cells, transfection with RSV-M protein caused the cells to proliferate at a slower rate than in control cells. The cell cycle analysis showed that RSV-M protein induced G1 phase arrest in A549 cells, and G1 and G2/M phase arrest in PHBE cells. Interestingly, RSV-M expression induced p53 and p21 accumulation and decreased phosphorylation of retinoblastoma protein (Rb). Further, induction of cell cycle arrest by RSV-M was not observed in a p53-deficient epithelial cell line (H1299). However, cell cycle arrest was restored after transfection of p53 cDNA into H1299 cells. Taken together, these results indicate that RSV-M protein regulates lung epithelial cell cycle through a p53-dependent pathway, which enhances RSV replication. PMID:22662266

  9. Respiratory syncytial virus matrix protein induces lung epithelial cell cycle arrest through a p53 dependent pathway.

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    Tao Bian

    Full Text Available Respiratory syncytial virus (RSV is the major cause of viral respiratory infections in children. Our previous study showed that the RSV infection induced lung epithelial cell cycle arrest, which enhanced virus replication. To address the mechanism of RSV-induced cell cycle arrest, we examined the contribution of RSV-matrix (RSV-M protein. In this report, we show that in both the A549 cell line and primary human bronchial epithelial (PHBE cells, transfection with RSV-M protein caused the cells to proliferate at a slower rate than in control cells. The cell cycle analysis showed that RSV-M protein induced G1 phase arrest in A549 cells, and G1 and G2/M phase arrest in PHBE cells. Interestingly, RSV-M expression induced p53 and p21 accumulation and decreased phosphorylation of retinoblastoma protein (Rb. Further, induction of cell cycle arrest by RSV-M was not observed in a p53-deficient epithelial cell line (H1299. However, cell cycle arrest was restored after transfection of p53 cDNA into H1299 cells. Taken together, these results indicate that RSV-M protein regulates lung epithelial cell cycle through a p53-dependent pathway, which enhances RSV replication.

  10. Eriocalyxin B induces apoptosis and cell cycle arrest in pancreatic adenocarcinoma cells through caspase- and p53-dependent pathways

    International Nuclear Information System (INIS)

    Pancreatic cancer is difficult to detect early and responds poorly to chemotherapy. A breakthrough in the development of new therapeutic agents is urgently needed. Eriocalyxin B (EriB), isolated from the Isodon eriocalyx plant, is an ent-kaurane diterpenoid with promise as a broad-spectrum anti-cancer agent. The anti-leukemic activity of EriB, including the underlying mechanisms involved, has been particularly well documented. In this study, we demonstrated for the first time EriB's potent cytotoxicity against four pancreatic adenocarcinoma cell lines, namely PANC-1, SW1990, CAPAN-1, and CAPAN-2. The effects were comparable to that of the chemotherapeutic camptothecin (CAM), but with much lower toxicity against normal human liver WRL68 cells. EriB's cytoxicity against CAPAN-2 cells was found to involve caspase-dependent apoptosis and cell cycle arrest at the G2/M phase. Moreover, the p53 pathway was found to be activated by EriB in these cells. Furthermore, in vivo studies showed that EriB inhibited the growth of human pancreatic tumor xenografts in BALB/c nude mice without significant secondary adverse effects. These results suggest that EriB should be considered a candidate for pancreatic cancer treatment. -- Highlights: ► We study Eriocalyxin B (EriB)'s cytotoxic effects on pancreatic cancer cell lines. ► EriB inhibits cell proliferation via mediation of apoptosis and cell cycle arrest. ► The effects are involved in caspase-dependent apoptosis and p53 pathway. ► In vivo study also shows EriB inhibits the growth of human pancreatic tumor. ► EriB can be a good candidate for chemotherapy in pancreatic cancer.

  11. Eriocalyxin B induces apoptosis and cell cycle arrest in pancreatic adenocarcinoma cells through caspase- and p53-dependent pathways

    Energy Technology Data Exchange (ETDEWEB)

    Li, Lin [School of Biomedical Sciences, The Chinese University of Hong Kong, Hong Kong (China); Institute of Chinese Medicine, The Chinese University of Hong Kong, Hong Kong (China); State Key Laboratory of Phytochemistry and Plant Resources in West China, The Chinese University of Hong Kong, Hong Kong (China); Yue, Grace G.L. [Institute of Chinese Medicine, The Chinese University of Hong Kong, Hong Kong (China); State Key Laboratory of Phytochemistry and Plant Resources in West China, The Chinese University of Hong Kong, Hong Kong (China); Lau, Clara B.S. [Institute of Chinese Medicine, The Chinese University of Hong Kong, Hong Kong (China); Institute of Chinese Medicine, The Chinese University of Hong Kong, Hong Kong (China); Sun, Handong [State Key Laboratory of Phytochemistry and Plant Resources in West China, Kunming Institute of Botany, CAS, Yunnan (China); Fung, Kwok Pui [School of Biomedical Sciences, The Chinese University of Hong Kong, Hong Kong (China); Institute of Chinese Medicine, The Chinese University of Hong Kong, Hong Kong (China); State Key Laboratory of Phytochemistry and Plant Resources in West China, The Chinese University of Hong Kong, Hong Kong (China); Leung, Ping Chung [Institute of Chinese Medicine, The Chinese University of Hong Kong, Hong Kong (China); State Key Laboratory of Phytochemistry and Plant Resources in West China, The Chinese University of Hong Kong, Hong Kong (China); Han, Quanbin, E-mail: simonhan@hkbu.edu.hk [Institute of Chinese Medicine, The Chinese University of Hong Kong, Hong Kong (China); State Key Laboratory of Phytochemistry and Plant Resources in West China, The Chinese University of Hong Kong, Hong Kong (China); School of Chinese Medicine, The Hong Kong Baptist University, Hong Kong (China); Leung, Po Sing, E-mail: psleung@cuhk.edu.hk [School of Biomedical Sciences, The Chinese University of Hong Kong, Hong Kong (China)

    2012-07-01

    Pancreatic cancer is difficult to detect early and responds poorly to chemotherapy. A breakthrough in the development of new therapeutic agents is urgently needed. Eriocalyxin B (EriB), isolated from the Isodon eriocalyx plant, is an ent-kaurane diterpenoid with promise as a broad-spectrum anti-cancer agent. The anti-leukemic activity of EriB, including the underlying mechanisms involved, has been particularly well documented. In this study, we demonstrated for the first time EriB's potent cytotoxicity against four pancreatic adenocarcinoma cell lines, namely PANC-1, SW1990, CAPAN-1, and CAPAN-2. The effects were comparable to that of the chemotherapeutic camptothecin (CAM), but with much lower toxicity against normal human liver WRL68 cells. EriB's cytoxicity against CAPAN-2 cells was found to involve caspase-dependent apoptosis and cell cycle arrest at the G2/M phase. Moreover, the p53 pathway was found to be activated by EriB in these cells. Furthermore, in vivo studies showed that EriB inhibited the growth of human pancreatic tumor xenografts in BALB/c nude mice without significant secondary adverse effects. These results suggest that EriB should be considered a candidate for pancreatic cancer treatment. -- Highlights: ► We study Eriocalyxin B (EriB)'s cytotoxic effects on pancreatic cancer cell lines. ► EriB inhibits cell proliferation via mediation of apoptosis and cell cycle arrest. ► The effects are involved in caspase-dependent apoptosis and p53 pathway. ► In vivo study also shows EriB inhibits the growth of human pancreatic tumor. ► EriB can be a good candidate for chemotherapy in pancreatic cancer.

  12. Chapter 10 the primary cilium coordinates signaling pathways in cell cycle control and migration during development and tissue repair

    DEFF Research Database (Denmark)

    Christensen, Søren T; Pedersen, Stine F; Satir, Peter; Veland, Iben R; Schneider, Linda

    2008-01-01

    Cell cycle control and migration are critical processes during development and maintenance of tissue functions. Recently, primary cilia were shown to take part in coordination of the signaling pathways that control these cellular processes in human health and disease. In this review, we present an...

  13. Resveratrol induces cell cycle arrest and apoptosis in malignant NK cells via JAK2/STAT3 pathway inhibition.

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    Ly Quoc Trung

    Full Text Available Natural killer (NK cell malignancies, particularly aggressive NK cell leukaemias and lymphomas, have poor prognoses. Although recent regimens with L-asparaginase substantially improved outcomes, novel therapeutic approaches are still needed to enhance clinical response. Resveratrol, a naturally occurring polyphenol, has been extensively studied for its anti-inflammatory, cardioprotective and anti-cancer activities. In this study, we investigated the potential anti-tumour activities of resveratrol against the NK cell lines KHYG-1, NKL, NK-92 and NK-YS. Resveratrol induced robust G0/G1 cell cycle arrest, significantly suppressed cell proliferation and induced apoptosis in a dose- and time-dependent manner for all four cell lines. In addition, resveratrol suppressed constitutively active STAT3 in all the cell lines and inhibited JAK2 phosphorylation but had no effect on other upstream mediators of STAT3 activation, such as PTEN, TYK2, and JAK1. Resveratrol also induced downregulation of the anti-apoptotic proteins MCL1 and survivin, two downstream effectors of the STAT3 pathway. Finally, resveratrol induced synergistic effect on the apoptotic and antiproliferative activities of L-asparaginase against KHYG-1, NKL and NK-92 cells. These results suggest that resveratrol may have therapeutic potential against NK cell malignancies. Furthermore, our finding that resveratrol is a bonafide JAK2 inhibitor extends its potential benefits to other diseases with dysregulated JAK2 signaling.

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

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    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

  15. A coherent framework for multiresolution analysis of biological networks with “memory”: Ras pathway, cell cycle, and immune system

    OpenAIRE

    Barbano, Paolo Emilio; Spivak, Marina; Feng, Jiawu; Antoniotti, Marco; Mishra, Bud

    2005-01-01

    Various biological processes exhibit characteristics that vary dramatically in response to different input conditions or changes in the history of the process itself. One of the examples studied here, the Ras-PKC-mitogen-activated protein kinase (MAPK) bistable pathway, follows two distinct dynamics (modes) depending on duration and strength of EGF stimulus. Similar examples are found in the behavior of the cell cycle and the immune system. A classification methodology, based on time-frequenc...

  16. Dysregulation of TFDP1 and of the cell cycle pathway in high-grade glioblastoma multiforme: a bioinformatic analysis.

    Science.gov (United States)

    Lu, X; Lv, X D; Ren, Y H; Yang, W D; Li, Z B; Zhang, L; Bai, X F

    2016-01-01

    Despite extensive research, the prognosis of high-grade glioblastoma multiforme (GBM) has improved only slightly because of the limited response to standard treatments. Recent advances (discoveries of molecular biomarkers) provide new opportunities for the treatment of GBM. The aim of the present study was to identify diagnostic biomarkers of high-grade GBM. First, we combined 3 microarray expression datasets to screen them for genes differentially expressed in patients with high-grade GBM relative to healthy subjects. Next, the target network was constructed via the empirical Bayesian coexpression approach, and centrality analysis and a molecular complex detection (MCODE) algorithm were performed to explore hub genes and functional modules. Finally, a validation test was conducted to verify the bioinformatic results. A total of 277 differentially expressed genes were identified according to the criteria P < 0.05 and |log2(fold change)| ≥ 1.5. These genes were most significantly enriched in the cell cycle pathway. Centrality analysis uncovered 9 hub genes; among them, TFDP1 showed the highest degree of connectivity (43) and is a known participant in the cell cycle pathway; this finding pointed to the important role of TFDP1 in the progression of high-grade GBM. Experimental validation mostly supported the bioinformatic results. According to our study results, the gene TFDP1 and the cell cycle pathway are strongly associated with high-grade GBM; this result may provide new insights into the pathogenesis of GBM. PMID:27323154

  17. ROLE OF PI3K-AKT-mTOR AND Wnt SIGNALING PATHWAYS IN G1-S TRANSITION OF CELL CYCLE IN CANCER CELLS

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    LAKSHMIPATHI eVADLAKONDA

    2013-04-01

    Full Text Available The PI3K–Akt pathway together with one of its downstream targets, the mechanistic target of rapamycin (mTOR is a highly deregulated pathway in cancers. There is a reciprocal relation between the Akt phosphorylation and mTOR complexes. Akt phosphorylated at T308 activates mTORC1 by inhibition of the tuberous sclerosis complex (TSC1/2, where as mTORC2 is recognized as the kinase that phosphorylates Akt at S473. Recent developments in the research on regulatory mechanisms of autophagy places mTORC1 mediated inhibition of autophagy at the central position in activation of proliferation and survival pathways in cells. Autophagy is a negative regulator of Wnt signaling pathway and the downstream effectors of Wnt signaling pathway, cyclin D1 and the c-Myc, are the key players in initiation of cell cycle and regulation of the G1-S transition in cancer cells. Production of reaction oxygen species (ROS, a common feature of a cancer cell metabolism, activates several downstream targets like the transcription factors FoxO, which play key roles in promoting the progression of cell cycle. A model is presented on the role of PI3K -Akt - mTOR and Wnt pathways in regulation of the progression of cell cycle through Go-G1-and S phases.

  18. Quantitative trait loci mapping reveals candidate pathways regulating cell cycle duration in Plasmodium falciparum

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    Siwo Geoffrey

    2010-10-01

    Full Text Available Abstract Background Elevated parasite biomass in the human red blood cells can lead to increased malaria morbidity. The genes and mechanisms regulating growth and development of Plasmodium falciparum through its erythrocytic cycle are not well understood. We previously showed that strains HB3 and Dd2 diverge in their proliferation rates, and here use quantitative trait loci mapping in 34 progeny from a cross between these parent clones along with integrative bioinformatics to identify genetic loci and candidate genes that control divergences in cell cycle duration. Results Genetic mapping of cell cycle duration revealed a four-locus genetic model, including a major genetic effect on chromosome 12, which accounts for 75% of the inherited phenotype variation. These QTL span 165 genes, the majority of which have no predicted function based on homology. We present a method to systematically prioritize candidate genes using the extensive sequence and transcriptional information available for the parent lines. Putative functions were assigned to the prioritized genes based on protein interaction networks and expression eQTL from our earlier study. DNA metabolism or antigenic variation functional categories were enriched among our prioritized candidate genes. Genes were then analyzed to determine if they interact with cyclins or other proteins known to be involved in the regulation of cell cycle. Conclusions We show that the divergent proliferation rate between a drug resistant and drug sensitive parent clone is under genetic regulation and is segregating as a complex trait in 34 progeny. We map a major locus along with additional secondary effects, and use the wealth of genome data to identify key candidate genes. Of particular interest are a nucleosome assembly protein (PFL0185c, a Zinc finger transcription factor (PFL0465c both on chromosome 12 and a ribosomal protein L7Ae-related on chromosome 4 (PFD0960c.

  19. 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

  20. AB109. Downregulation of tNASP inhibits proliferation through regulating cell cycle-related proteins and inactive ERK/MAPK signal pathway in renal cell carcinoma cells

    Science.gov (United States)

    Fang, Jianzheng; Wang, Hainan; Cheng, Gong; Wang, Shangqian; Deng, Yunfei; Song, Zhen; Xu, Aiming; Liu, Bianjiang; Wang, Zengjun

    2016-01-01

    Objective Nuclear auto-antigenic sperm protein (NASP), initially described as a highly auto-immunogenic testis and sperm-specific protein, is a histone chaperone that is proved to present in all dividing cells. NASP has two splice variants: testicular NASP (tNASP) and somatic form of NASP (sNASP). Only cancer, germ, transformed, and embryonic cells have a high level of expression of the tNASP. Up to now, little has been known about tNASP in renal cell carcinoma (RCC). In the present study, the molecular mechanism of tNASP in RCC was explored. Methods The expression level of tNASP in 16 paired human RCC specimens was determined. Downregulation of tNASP by small interfering RNA (siRNA) was transfected in RCC cell lines. The effect of downregulation of tNASP by siRNA on cell colony formation and proliferation was examined by colony formation assay and CCK-8 assay, cell cycle was analyzed by flow cytometry, and the expression of cyclin D1 and P21 were detected by Western blotting. ERK/MAPK signaling was also analyzed. Results tNASP has a relative high expression level in human RCC tissues. Via upregulation of P21 and downregulation of cyclinD1, silence of tNASP can inhibit cell proliferation, which induces cell cycle arrest. Furthermore, ERK signaling pathway is confirmed to mediate the regulation of cell cycle-related proteins caused by silence of tNASP. Conclusions Our research demonstrates that knockdown of tNASP effectively inhibits the proliferation and causes G1 phase arrest through ERK/MAPK signal pathway.

  1. De-regulated microRNAs in pediatric cancer stem cells target pathways involved in cell proliferation, cell cycle and development.

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    Patricia C Sanchez-Diaz

    Full Text Available BACKGROUND: microRNAs (miRNAs have been implicated in the control of many biological processes and their deregulation has been associated with many cancers. In recent years, the cancer stem cell (CSC concept has been applied to many cancers including pediatric. We hypothesized that a common signature of deregulated miRNAs in the CSCs fraction may explain the disrupted signaling pathways in CSCs. METHODOLOGY/RESULTS: Using a high throughput qPCR approach we identified 26 CSC associated differentially expressed miRNAs (DEmiRs. Using BCmicrO algorithm 865 potential CSC associated DEmiR targets were obtained. These potential targets were subjected to KEGG, Biocarta and Gene Ontology pathway and biological processes analysis. Four annotated pathways were enriched: cell cycle, cell proliferation, p53 and TGF-beta/BMP. Knocking down hsa-miR-21-5p, hsa-miR-181c-5p and hsa-miR-135b-5p using antisense oligonucleotides and small interfering RNA in cell lines led to the depletion of the CSC fraction and impairment of sphere formation (CSC surrogate assays. CONCLUSION: Our findings indicated that CSC associated DEmiRs and the putative pathways they regulate may have potential therapeutic applications in pediatric cancers.

  2. Wogonin induced G1 cell cycle arrest by regulating Wnt/β-catenin signaling pathway and inactivating CDK8 in human colorectal cancer carcinoma cells

    International Nuclear Information System (INIS)

    Highlights: • Wogonin inhibited HCT116 cells growth and arrested at G1 phase of the cell cycle. • Wogonin down-regulated the canonical Wnt/β-catenin signaling pathway. • Wogonin interfered in the combination of β-catenin and TCF/Lef. • Wogonin limited the kinase activity of CDK8. - Abstract: Wogonin, a naturally occurring mono-flavonoid, has been reported to have tumor therapeutic potential and good selectivity both in vitro and in vivo. Herein, we investigated the anti-proliferation effects and associated mechanisms of wogonin in human colorectal cancer in vitro. The flow-cytometric analysis showed that wogonin induced a G1 phase cell cycle arrest in HCT116 cells in a concentration- and time-dependent manner. Meanwhile, the cell cycle-related proteins, such as cyclin A, E, D1, and CDK2, 4 were down-regulated in wogonin-induced G1 cell cycle arrest. Furthermore, we showed that the anti-proliferation and G1 arrest effect of wogonin on HCT116 cells was associated with deregulation of Wnt/β-catenin signaling pathway. Wogonin-treated cells showed decreased intracellular levels of Wnt proteins, and activated degradation complex to phosphorylated and targeted β-catenin for proteasomal degradation. Wogonin inhibited β-catenin-mediated transcription by interfering in the transcriptional activity of TCF/Lef, and repressing the kinase activity of CDK8 which has been considered as an oncogene involving in the development of colorectal cancers. Moreover, CDK8 siRNA-transfected HCT116 cells showed similar results to wogonin treated cells. Thus, our data suggested that wogonin induced anti-proliferation and G1 arrest via Wnt/β-catenin signaling pathway and it can be developed as a therapeutic agent against human colorectal cancer

  3. Adenosine induces cell cycle arrest and apoptosis via cyclinD1/Cdk4 and Bcl-2/Bax pathways in human ovarian cancer cell line OVCAR-3.

    Science.gov (United States)

    Shirali, Saeid; Aghaei, Mahmoud; Shabani, Mahdi; Fathi, Mojtaba; Sohrabi, Majid; Moeinifard, Marzieh

    2013-04-01

    Adenosine is a regulatory molecule with widespread physiological effects in almost every cells and acts as a potent regulator of cell growth. Adenosine has been shown to inhibit cell growth and induce apoptosis in the several cancer cells via caspase activation and Bcl-2/Bax pathway. The present study was designed to understand the mechanism underlying adenosine-induced apoptosis in the OVCAR-3 human ovarian cancer cells. MTT viability, BrdU and cell counting assays were used to study the cell proliferation effect of adenosine in presence of adenosine deaminase inhibitor and the nucleoside transporter inhibitor. Cell cycle analysis, propidium iodide and annexin V staining, caspase-3 activity assay, cyclinD1, Cdk4, Bcl-2 and Bax protein expressions were assessed to detect apoptosis. Adenosine significantly inhibited cell proliferation in a concentration-dependent manner in OVCAR-3 cell line. Adenosine induced cell cycle arrest in G0/G1 phase via Cdk4/cyclinD1-mediated pathway. Adenosine induced apoptosis, which was determined by Annexin V-FITC staining and increased sub-G1 population. Moreover, down-regulation of Bcl-2 protein expression, up-regulation of Bax protein expression and activation of caspase-3 were observed in response to adenosine treatment. The results of this study suggest that extracellular adenosine induced G1 cell cycle arrest and apoptosis in ovarian cancer cells via cyclinD1/ Cdk4 and Bcl-2/Bax pathways and caspase-3 activation. These data might suggest that adenosine could be used as an agent for the treatment of ovarian cancer. PMID:23345014

  4. Investigation of anticancer mechanism of oleuropein via cell cycle and apoptotic pathways in SH-SY5Y neuroblastoma cells.

    Science.gov (United States)

    Seçme, Mücahit; Eroğlu, Canan; Dodurga, Yavuz; Bağcı, Gülseren

    2016-07-01

    Neuroblastoma is one of the most common types of pediatric tumors that can spread quickly in neuronal tissues. Oleuropein which is active compound of olive leaves, belongs to polyphenols group and has antioxidant, anti-microbial, anti-inflammatory, anti-hypertensive and anti-carcinogenic effects. The aim of the study is to determine the therapeutic effects of oleuropein on cell proliferation, invasion, colony formation, cell cycle and apoptotic mechanisms in SH-SY5Y neuroblastoma cell line under in vitro conditions. The effect of oleuropein on cell viability was determined by XTT method. 84 cell cycle control and 84 apoptosis related genes were evaluated by RT-PCR. Effects of oleuropein on apoptosis were researched by TUNEL assay. Protein expressions were determined by western blot analysis. Effects of oleuropein on cell invasion, colony formation and migration were detected by matrigel-chamber, colony formation assay and wound-healing assay, respectively. IC50 value of oleuropein in SH-SY5Y cells was detected as 350μM at 48th hours. It is determined that oleuropein causes cell cycle arrest by down-regulating of CylinD1,CylinD2,CyclinD3,CDK4,CDK6 and up-regulating of p53 and CDKN2A, CDKN2B, CDKN1A gene expressions. Oleuropein also induces apoptosis by inhibiting of Bcl-2 and activating of Bax,caspase-9 and caspase-3 gene expressions. Apoptotic cell ratio was found 36.4±3.27% in oleuropein dose group. Oleuropein decreased invasion in SH-SY5Y cells and suppressed colony numbers in ratio of 53.6±4.71%.Our results demonstrated that oleuropein can be a therapeutic agent in the treatment of neuroblastoma. PMID:27032461

  5. The PI3K-Akt-mTOR pathway regulates Aβ oligomer induced neuronal cell cycle events

    Directory of Open Access Journals (Sweden)

    Herrup Karl

    2009-03-01

    Full Text Available Abstract Accumulating evidence suggests that neurons prone to degeneration in Alzheimer's Disease (AD exhibit evidence of re-entry into an aberrant mitotic cell cycle. Our laboratory recently demonstrated that, in a genomic amyloid precursor protein (APP mouse model of AD (R1.40, neuronal cell cycle events (CCEs occur in the absence of beta-amyloid (Aβ deposition and are still dependent upon the amyloidogenic processing of the amyloid precursor protein (APP. These data suggested that soluble Aβ species might play a direct role in the induction of neuronal CCEs. Here, we show that exposure of non-transgenic primary cortical neurons to Aβ oligomers, but not monomers or fibrils, results in the retraction of neuronal processes, and induction of CCEs in a concentration dependent manner. Retraction of neuronal processes correlated with the induction of CCEs and the Aβ monomer or Aβ fibrils showed only minimal effects. In addition, we provide evidence that induction of neuronal CCEs are autonomous to primary neurons cultured from the R1.40 mice. Finally, our results also demonstrate that Aβ oligomer treated neurons exhibit elevated levels of activated Akt and mTOR (mammalian Target Of Rapamycin and that PI3K, Akt or mTOR inhibitors blocked Aβ oligomer-induced neuronal CCEs. Taken together, these results demonstrate that Aβ oligomer-based induction of neuronal CCEs involve the PI3K-Akt-mTOR pathway.

  6. Gene expression profiling analysis reveals arsenic-induced cell cycle arrest and apoptosis in p53-proficient and p53-deficient cells through differential gene pathways

    International Nuclear Information System (INIS)

    Arsenic (As) is a well-known environmental toxicant and carcinogen as well as an effective chemotherapeutic agent. The underlying mechanism of this dual capability, however, is not fully understood. Tumor suppressor gene p53, a pivotal cell cycle checkpoint signaling protein, has been hypothesized to play a possible role in mediating As-induced toxicity and therapeutic efficiency. In this study, we found that arsenite (As3+) induced apoptosis and cell cycle arrest in a dose-dependent manner in both p53+/+ and p53-/- mouse embryonic fibroblasts (MEFs). There was, however, a distinction between genotypes in the apoptotic response, with a more prominent induction of caspase-3 in the p53-/- cells than in the p53+/+ cells. To examine this difference further, a systems-based genomic analysis was conducted comparing the critical molecular mechanisms between the p53 genotypes in response to As3+. A significant alteration in the Nrf2-mediated oxidative stress response pathway was found in both genotypes. In p53+/+ MEFs, As3+ induced p53-dependent gene expression alterations in DNA damage and cell cycle regulation genes. However, in the p53-/- MEFs, As3+ induced a significant up-regulation of pro-apoptotic genes (Noxa) and down-regulation of genes in immune modulation. Our findings demonstrate that As-induced cell death occurs through a p53-independent pathway in p53 deficient cells while apoptosis induction occurs through p53-dependent pathway in normal tissue. This difference in the mechanism of apoptotic responses between the genotypes provides important information regarding the apparent dichotomy of arsenic's dual mechanisms, and potentially leads to further advancement of its utility as a chemotherapeutic agent

  7. Two distinct pathways responsible for the loading of CENP-A to centromeres in the fission yeast cell cycle.

    Science.gov (United States)

    Takahashi, Kohta; Takayama, Yuko; Masuda, Fumie; Kobayashi, Yasuyo; Saitoh, Shigeaki

    2005-03-29

    CENP-A is a centromere-specific histone H3 variant that is- essential for faithful chromosome segregation in all eukaryotes thus far investigated. We genetically identified two factors, Ams2 and Mis6, each of which is required for the correct centromere localization of SpCENP-A (Cnp1), the fission yeast homologue of CENP-A. Ams2 is a cell-cycle-regulated GATA factor that localizes on the nuclear chromatin, including on centromeres, during the S phase. Ams2 may be responsible for the replication-coupled loading of SpCENP-A by facilitating nucleosomal formation during the S phase. Consistently, overproduction of histone H4, but not that of H3, suppressed the defect of SpCENP-A localization in Ams2-deficient cells. We demonstrated the existence of at least two distinct phases for SpCENP-A loading during the cell cycle: the S phase and the late-G2 phase. Ectopically induced SpCENP-A was efficiently loaded onto the centromeres in G2-arrested cells, indicating that SpCENP-A probably undergoes replication-uncoupled loading after the completion of S phase. This G2 loading pathway of SpCENP-A may require Mis6, a constitutive centromere-binding protein that is also implicated in the Mad2-dependent spindle attachment checkpoint response. Here, we discuss the functional relationship between the flexible loading mechanism of CENP-A and the plasticity of centromere chromatin formation in fission yeast. PMID:15897182

  8. P53-mediated cell cycle arrest and apoptosis through a caspase-3-independent, but caspase-9-dependent pathway in oridonin-treated MCF-7 human breast cancer cells

    Institute of Scientific and Technical Information of China (English)

    Qiao CUI; Jing-hua YU; Jin-nan WU; Shin-ichi TASHIRO; Satoshi ONODERA; Mutsuhiko MINAMI; Takashi IKEJIMA

    2007-01-01

    Aim: To study the caspase-3-independent mechanisms in oridonin-induced MCF-7 human breast cancer cell apoptosis in vitro. Methods: The viability of oridonin-treated MCF-7 cells was measured by MTT (thiazole blue) assay. Apoptotic cells with condensed nuclei were visualized by phase contrast microscopy. Nucleoso-mal DNA fragmentation was assayed by agarose gel electrophoresis. The apoptotic ratio was determined by lactate dehydrogenase assay. Cell cycle alternation and mitochondrial membrane potential were measured by flow cytometric analysis. Bax, Bcl-2, caspase-3, caspase-9, heat shock protein (Hsp)90, p53, p-p53, p21, Poly (ADP-ribose) polymerase (PARP), and the inhibitor of caspase-activated Dnase (ICAD) protein expressions were detected by Western blot analysis. Results: Oridonin inhibited cell growth in a time- and dose-dependent manner. Cell cycle was altered through the upregulation of p53 and p21 protein expressions. Pan-caspase inhibitor Z-VAD-fmk and calpain inhibitor Ⅱ both decreased cell death ratio. Nucleosomal DNA fragmentation and the downregulation of △ψmit were detected in oridonin-induced MCF-7 cell apoptosis, which was involved in a postmitochondrial caspase-9-dependent pathway. Decreased Bcl-2 and Hsp90 expression levels and increased Bax and p21 expression levels were positively correlated with elevated levels of phosphorylated p53 phosphorylation. Moreover, PARP was partially cleaved by calpain rather than by capase-3. Conclusion: DNA damage provoked alternations in the mitochondrial and caspase-9 pathways as well as p53-mediated cell cycle arrest, but was not related to caspase-3 activity in oridonin-induced MCF-7 cells.

  9. Cucurbitacin-I (JSI-124) activates the JNK/c-Jun signaling pathway independent of apoptosis and cell cycle arrest in B Leukemic Cells

    International Nuclear Information System (INIS)

    Cucurbitacin-I (JSI-124) is potent inhibitor of JAK/STAT3 signaling pathway and has anti-tumor activity in a variety of cancer including B cell leukemia. However, other molecular targets of JSI-124 beyond the JAK/STAT3 pathway are not fully understood. BJAB, I-83, NALM-6 and primary CLL cells were treated with JSI-124 as indicated. Apoptosis was measured using flow cytometry for accumulation of sub-G1 phase cells (indicator of apoptosis) and Annexin V/PI staining. Cell cycle was analyzed by FACS for DNA content of G1 and G2 phases. Changes in phosphorylation and protein expression of p38, Erk1/2, JNK, c-Jun, and XIAP were detected by Western blot analysis. STAT3 and c-Jun genes were knocked out using siRNA transfection. VEGF expression was determined by mRNA and protein levels by RT-PCR and western blotting. Streptavidin Pull-Down Assay was used to determine c-Jun binding to the AP-1 DNA binding site. Herein, we show that JSI-124 activates c-Jun N-terminal kinase (JNK) and increases both the expression and serine phosphorylation of c-Jun protein in the B leukemic cell lines BJAB, I-83 and NALM-6. JSI-124 also activated MAPK p38 and MAPK Erk1/2 albeit at lower levels than JNK activation. Inhibition of the JNK signaling pathway failed to effect cell cycle arrest or apoptosis induced by JSI-124 but repressed JSI-124 induced c-Jun expression in these leukemia cells. The JNK pathway activation c-Jun leads to transcriptional activation of many genes. Treatment of BJAB, I-83, and NALM-6 cells with JSI-124 lead to an increase of Vascular Endothelial Growth Factor (VEGF) at both the mRNA and protein level. Knockdown of c-Jun expression and inhibition of JNK activation significantly blocked JSI-124 induced VEGF expression. Pretreatment with recombinant VEGF reduced JSI-124 induced apoptosis. Taken together, our data demonstrates that JSI-124 activates the JNK signaling pathway independent of apoptosis and cell cycle arrest, leading to increased VEGF expression

  10. Plumbagin elicits differential proteomic responses mainly involving cell cycle, apoptosis, autophagy, and epithelial-to-mesenchymal transition pathways in human prostate cancer PC-3 and DU145 cells

    Directory of Open Access Journals (Sweden)

    Qui JX

    2015-01-01

    critical role in the regulation of cell cycle, apoptosis, autophagy, epithelial to mesenchymal transition (EMT, and reactive oxygen species generation. The proteomic study showed substantial differences in response to PLB treatment between PC-3 and DU145 cells. PLB treatment significantly modulated the expression of critical proteins that regulate cell cycle, apoptosis, and EMT signaling pathways in PC-3 cells but not in DU145 cells. Consistently, our Western blotting analysis validated the bioinformatic and proteomic data and confirmed the modulating effects of PLB on important proteins that regulated cell cycle, apoptosis, autophagy, and EMT in PC-3 and DU145 cells. The data from the Western blot assay could not display significant differences between PC-3 and DU145 cells. These findings indicate that PLB elicits different proteomic responses in PC-3 and DU145 cells involving proteins and pathways that regulate cell cycle, apoptosis, autophagy, reactive oxygen species production, and antioxidation/oxidation homeostasis. This is the first systematic study with integrated computational, proteomic, and functional analyses revealing the networks of signaling pathways and differential proteomic responses to PLB treatment in prostate cancer cells. Quantitative proteomic analysis using SILAC represents an efficient and highly sensitive approach to identify the target networks of anticancer drugs like PLB, and the data may be used to discriminate the molecular and clinical subtypes, and to identify new therapeutic targets and biomarkers, for prostate cancer. Further studies are warranted to explore the potential of quantitative proteomic analysis in the identification of new targets and biomarkers for prostate cancer.Keywords: EMT, proteomics, SILAC

  11. Midazolam regulated caspase pathway, endoplasmic reticulum stress, autophagy, and cell cycle to induce apoptosis in MA-10 mouse Leydig tumor cells

    Directory of Open Access Journals (Sweden)

    So EC

    2016-04-01

    Full Text Available Edmund Cheung So,1,2 Yung-Chia Chen,3 Shu-Chun Wang,4 Chia-Ching Wu,4 Man-Chi Huang,4 Meng-Shao Lai,4 Bo-Syong Pan,4,5 Fu-Chi Kang,6 Bu-Miin Huang4 1Department of Anesthesia, An Nan Hospital, China Medical University, Tainan, Taiwan, Republic of China; 2Department of Anesthesia, School of Medicine, China Medical University, Taichung, Taiwan; Republic of China; 3Department of Anatomy, School of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan, Republic of China; 4Department of Cell Biology and Anatomy, College of Medicine, National Cheng Kung University, Tainan, Taiwan, Republic of China; 5Department of Cancer Biology, Wake Forest University School of Medicine, Winston Salem, NC, USA; 6Department of Anesthesia, Chi Mei Medical Center, Chiali, Tainan, Taiwan, Republic of China Purpose: Midazolam is widely used as a sedative and anesthetic induction agent by modulating the different GABA receptors in the central nervous system. Studies have also shown that midazolam has an anticancer effect on various tumors. In a previous study, we found that midazolam could induce MA-10 mouse Leydig tumor cell apoptosis by activating caspase cascade. However, the detailed mechanism related to the upstream and downstream pathways of the caspase cascade, such as endoplasmic reticulum (ER stress, autophagy, and p53 pathways plus cell cycle regulation in MA-10 mouse Leydig tumor cells, remains elusive.Methods: Flow cytometry assay and Western blot analyses were exploited.Results: Midazolam significantly decreased cell viability but increased sub-G1 phase cell numbers in MA-10 cells (P<0.05. Annexin V/propidium iodide double staining further confirmed that midazolam induced apoptosis. In addition, expressions of Fas and Fas ligand could be detected in MA-10 cells with midazolam treatments, and Bax translocation and cytochrome c release were also involved in midazolam-induced MA-10 cell apoptosis. Moreover, the staining and expression of LC3-II proteins could

  12. Lidamycin induces marked G2 cell cycle arrest in human colon carcinoma HT-29 cells through activation of p38 MAPK pathway.

    Science.gov (United States)

    Liu, Xia; Bian, Chunjing; Ren, Kaihuan; Jin, Haixia; Li, Baowei; Shao, Rong-Guang

    2007-03-01

    Lidamycin (LDM), a member of the enediyne antibiotic family, is presently undergoing phase I clinical trials in P.R. China. In this study, we investigated the mechanisms of LDM-induced cell cycle arrest in order to support its use in clinical cancer therapy. Using human colon carcinoma HT-29 cells, we observed that LDM induced G2 cell cycle arrest in a time- and dose-dependent manner. LDM-induced G2 arrest was associated with increasing phosphorylation of Chk1, Chk2, Cdc25C, Cdc2 and expression of Cdc2 and cyclin B1. In addition, cytoplasmic localization of cyclin B1 was also involved in LDM-induced G2 arrest. Moreover, we found that p38 MAPK pathway contributed to LDM-induced G2 arrest. Inhibition of p38 MAPK by its inhibitor SB203580 not only attenuated LDM-induced G2 arrest but also potentiated LDM-induced apoptosis, which was accompanied by decreasing phosphorylation of Cdc2 and increasing expression of FasL and phosphorylation of JNK. Finally, we demonstrated that cells at G1 phase were more sensitive to LDM. Together, our findings suggest that p38 MAPK signaling pathway is involved in LDM-induced G2 arrest, at least partly, and a combination of LDM with p38 MAPK inhibitor may represent a new strategy for human colon cancer therapy. PMID:17273739

  13. Antihepatocellular Carcinoma Potential of Tetramethylpyrazine Induces Cell Cycle Modulation and Mitochondrial-Dependent Apoptosis: Regulation of p53 Signaling Pathway in HepG2 Cells In Vitro.

    Science.gov (United States)

    Bi, Lei; Yan, Xiaojing; Chen, Weiping; Gao, Jing; Qian, Lei; Qiu, Shuang

    2016-06-01

    Tetramethylpyrazine (TMP) was originally isolated from a traditional Chinese herbal medicine, Ligusticum chuanxiong In the present study, TMP exhibits potent antitumor activities in vitro. However, the molecular mechanisms remain to be defined. Hence, this study aims to investigate the antiproliferative and apoptotic effects of TMP on HepG2 and elucidate the underlying mechanisms. Analyses using Cell Counting Kit-8 and real-time cell analyzer indicated that TMP significantly inhibited HepG2 cell proliferation. We also observed that TMP induced cell cycle arrest at the G0/G1 checkpoint and apoptosis, using flow cytometry and high-content screening. Furthermore, our results predicted that TMP could directly decrease mitochondrial membrane potential (Δψm), increase the release of cytochrome c, and increase caspase activation, indicating that mitochondrial pathway apoptosis could be the mechanism for TMP within HepG2 cells. Moreover, TMP altered expression of p53 and the Bcl-2/Bax protein ratio, which revealed that TMP induced cell cycle arrest and caspase-dependent mitochondrial apoptosis in HepG2 cells in vitro. These studies provided mechanistic insights into the antitumor properties of TMP, which may be explored as a potential option for treatment of hepatocellular carcinoma. PMID:27179035

  14. ZIC1 modulates cell-cycle distributions and cell migration through regulation of sonic hedgehog, PI3K and MAPK signaling pathways in gastric cancer

    International Nuclear Information System (INIS)

    ZIC1, a vital transcription factor with zinc finger domains, has been implicated in the process of neural development. We previously showed that ZIC1 may function as a tumour suppressor in gastrointestinal cancers. However, the molecular mechanism underlying ZIC1 participation in tumour progression remains unknown. The role of ZIC1 on cell proliferation and migration was examined. The regulation of sonic hedgehog (Shh), phosphoinositide 3-kinase (PI3K) and mitogen-activated protein kinase (MAPK) signaling pathways after ectopic expression of ZIC1 in gastric cancer cells were evaluated. Overexpression of ZIC1 contributes to the inhibition of cell proliferation migration and cell-cycle distribution in gastric cancer. The modulation of G1/S checkpoint by ZIC1 is mainly mediated through the regulation of cyclin-dependent kinases (p21 Waf1/Cip1, p27 Kip1 and cyclin D1). In addition, ZIC1 can inactivate the level of phospholated Akt and Erk1/2, and transcriptionally regulate sonic hedgehog (Shh) signaling, thus leading to regulate the expression of p21 Waf1/Cip1 and cyclin D1. Finally, we have systemically identified ZIC1 downstream targets by cDNA microarray analysis and revealed that 132 genes are down-regulated and 66 genes are up-regulated after transfection with ZIC1 in gastric cancer cells. These candidate genes play critical roles in cell proliferation, cell cycle and cell motility. Overexpression of ZIC1 results in inactivation of Shh, PI3K and MAPK signaling pathways, as well as regulation of multiple downstream targets which are essential for the development and progression of gastric cancer. ZIC1 serves as a potential therapeutic target for gastric cancer

  15. Zerumbone-loaded nanostructured lipid carrier induces G2/M cell cycle arrest and apoptosis via mitochondrial pathway in a human lymphoblastic leukemia cell line

    Directory of Open Access Journals (Sweden)

    Rahman HS

    2014-01-01

    Full Text Available Heshu Sulaiman Rahman,1–3 Abdullah Rasedee,1,2 Ahmad Bustamam Abdul,2,4 Nazariah Allaudin Zeenathul,1,2 Hemn Hassan Othman,1,3 Swee Keong Yeap,2 Chee Wun How,2 Wan Abd Ghani Wan Nor Hafiza4,51Faculty of Veterinary Medicine, 2Institute of Bioscience, Universiti Putra Malaysia, Selangor, Malaysia; 3Faculty of Veterinary Medicine, University of Sulaimanyah, Sulaimanyah City, Kurdistan Region, Northern Iraq; 4Faculty of Medicine and Health Science, Universiti Putra Malaysia, Selangor, Malaysia; 5College of Medical Laboratory Technology, Institute for Medical Research, Kuala Lumpur, MalaysiaAbstract: This investigation evaluated the antileukemia properties of a zerumbone (ZER-loaded nanostructured lipid carrier (NLC prepared by hot high-pressure homogenization techniques in an acute human lymphoblastic leukemia (Jurkat cell line in vitro. The apoptogenic effect of the ZER-NLC on Jurkat cells was determined by fluorescent and electron microscopy, Annexin V-fluorescein isothiocyanate, Tdt-mediated dUTP nick-end labeling assay, cell cycle analysis, and caspase activity. An MTT (3-(4,5-dimethylthiazol-2-yl-2,5 diphenyltetrazolium bromide assay showed that ZER-NLC did not have adverse effects on normal human peripheral blood mononuclear cells. ZER-NLC arrested the Jurkat cells at G2/M phase with inactivation of cyclin B1 protein. The study also showed that the antiproliferative effect of ZER-NLC on Jurkat cells is through the intrinsic apoptotic pathway via activation of caspase-3 and caspase-9, release of cytochrome c from the mitochondria into the cytosol, and subsequent cleavage of poly (adenosine diphosphate-ribose polymerase (PARP. These findings show that the ZER-NLC is a potentially useful treatment for acute lymphoblastic leukemia in humans.Keywords: zerumbone-loaded nanostructured lipid carrier, cell cycle arrest, apoptosis, mitochondrial pathway

  16. Dexamethasone suppresses DU145 cell proliferation and cell cycle through inhibition of the extracellular signal-regulated kinase 1/2 pathway and cyclin D1 expression

    Institute of Scientific and Technical Information of China (English)

    Qing-Zhen Gao; Jia-Ju Lu; Zi-Dong Liu; Hui Zhang; Shao-Mei Wang; He Xu

    2008-01-01

    Aim: To determine the mechanisms of glucocorticoids in inhibiting advanced prostate cancer growth. Methods: The cell proliferation and cell cycle of prostate cancer DU145 cells following dexamethasone treatment were determined by proliferation assay and fluorescence-activated cell sorter. Western blot analysis was carried out to evaluate the effects of dexamethasone on phosphorylation of extracellular signal-regulated kinase (ERK)1/2 and expression of cyclin D1 in DU145 cells with or without glucocorticoid receptor (GR) antagonist RU486. Reverse transcription- polymerase chain reaction verified the expression of GR mRNA in DU145 cells. Results: Dexamethasone signifi- cantly inhibited DU145 cell proliferation at the G0/G1 phase. Western blot analysis showed a dramatic reduction of ERK1/2 activity and cyclin D1 expression in dexamethasone-treated cells. The decreased phosphorylation of ERK1/2 in dexamethasone-treated cells was attenuated by GR blockade. Additionally, the effects of dexamethasone in inhibiting cyclin D1 expression were altered by GR blockade. Conclusion: Dexamethasone suppresses DU 145 cell prolifera- tion and cell cycle, and the underlying mechanisms are through the inhibition of phosphorylation of ERK1/2 and cyclin D1 expression. The inhibition of ERK1/2 phosphorylation and cyclin D1 expression is attenuated by GR blockade, suggesting that GR regulates ERK1/2 and cyclin D 1 pathways. These observations suggest that dexamethasone has a potential clinical application in prostate cancer therapy. (Asian JAndrol 2008 Jul; 10: 635-641)

  17. The PI3K-Akt-mTOR pathway regulates Aβ oligomer induced neuronal cell cycle events

    OpenAIRE

    Herrup Karl; Chludzinski Alexandra; Miller Megan; Bhaskar Kiran; Zagorski Michael; Lamb Bruce T

    2009-01-01

    Abstract Accumulating evidence suggests that neurons prone to degeneration in Alzheimer's Disease (AD) exhibit evidence of re-entry into an aberrant mitotic cell cycle. Our laboratory recently demonstrated that, in a genomic amyloid precursor protein (APP) mouse model of AD (R1.40), neuronal cell cycle events (CCEs) occur in the absence of beta-amyloid (Aβ) deposition and are still dependent upon the amyloidogenic processing of the amyloid precursor protein (APP). These data suggested that so...

  18. Respiratory Syncytial Virus Matrix Protein Induces Lung Epithelial Cell Cycle Arrest through a p53 Dependent Pathway

    OpenAIRE

    Bian, Tao; John D Gibbs; Örvell, Claes; Imani, Farhad

    2012-01-01

    Respiratory syncytial virus (RSV) is the major cause of viral respiratory infections in children. Our previous study showed that the RSV infection induced lung epithelial cell cycle arrest, which enhanced virus replication. To address the mechanism of RSV-induced cell cycle arrest, we examined the contribution of RSV-matrix (RSV-M) protein. In this report, we show that in both the A549 cell line and primary human bronchial epithelial (PHBE) cells, transfection with RSV-M protein caused the ce...

  19. Azithromycin treatment alters gene expression in inflammatory, lipid metabolism, and cell cycle pathways in well-differentiated human airway epithelia.

    Directory of Open Access Journals (Sweden)

    Carla Maria P Ribeiro

    Full Text Available Prolonged macrolide antibiotic therapy at low doses improves clinical outcome in patients affected with diffuse panbronchiolitis and cystic fibrosis. Consensus is building that the therapeutic effects are due to anti-inflammatory, rather than anti-microbial activities, but the mode of action is likely complex. To gain insights into how the macrolide azithromycin (AZT modulates inflammatory responses in airways, well-differentiated primary cultures of human airway epithelia were exposed to AZT alone, an inflammatory stimulus consisting of soluble factors from cystic fibrosis airways, or AZT followed by the inflammatory stimulus. RNA microarrays were conducted to identify global and specific gene expression changes. Analysis of gene expression changes revealed that the AZT treatment alone altered the gene profile of the cells, primarily by significantly increasing the expression of lipid/cholesterol genes and decreasing the expression of cell cycle/mitosis genes. The increase in cholesterol biosynthetic genes was confirmed by increased filipin staining, an index of free cholesterol, after AZT treatment. AZT also affected genes with inflammatory annotations, but the effect was variable (both up- and down-regulation and gene specific. AZT pretreatment prevented the up-regulation of some genes, such as MUC5AC and MMP9, triggered by the inflammatory stimulus, but the up-regulation of other inflammatory genes, e.g., cytokines and chemokines, such as interleukin-8, was not affected. On the other hand, HLA genes were increased by AZT. Notably, secreted IL-8 protein levels did not reflect mRNA levels, and were, in fact, higher after AZT pretreatment in cultures exposed to the inflammatory stimulus, suggesting that AZT can affect inflammatory pathways other than by altering gene expression. These findings suggest that the specific effects of AZT on inflamed and non-inflamed airway epithelia are likely relevant to its clinical activity, and their apparent

  20. Two specific drugs, BMS-345541 and purvalanol A induce apoptosis of HTLV-1 infected cells through inhibition of the NF-kappaB and cell cycle pathways

    Directory of Open Access Journals (Sweden)

    Wu Weilin

    2008-06-01

    Full Text Available Abstract Human T-cell leukemia virus type-1 (HTLV-1 induces adult T-cell leukemia/lymphoma (ATL/L, a fatal lymphoproliferative disorder, and HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP, a chronic progressive disease of the central nervous system after a long period of latent infection. Although the mechanism of transformation and leukemogenesis is not fully elucidated, there is evidence to suggest that the viral oncoprotein Tax plays a crucial role in these processes through the regulation of several pathways including NF-κB and the cell cycle pathways. The observation that NF-κB, which is strongly induced by Tax, is indispensable for the maintenance of the malignant phenotype of HTLV-1 by regulating the expression of various genes involved in cell cycle regulation and inhibition of apoptosis provides a possible molecular target for these infected cells. To develop potential new therapeutic strategies for HTLV-1 infected cells, in this present study, we initially screened a battery of NF-κB and CDK inhibitors (total of 35 compounds to examine their effects on the growth and survival of infected T-cell lines. Two drugs namely BMS-345541 and Purvalanol A exhibited higher levels of growth inhibition and apoptosis in infected cell as compared to uninfected cells. BMS-345541 inhibited IKKβ kinase activity from HTLV-1 infected cells with an IC50 (the 50% of inhibitory concentration value of 50 nM compared to 500 nM from control cells as measured by in vitro kinase assays. The effects of Purvalanol A were associated with suppression of CDK2/cyclin E complex activity as previously shown by us. Combination of both BMS-345541 and Purvalanol A showed a reduced level of HTLV-1 p19 Gag production in cell culture. The apparent apoptosis in these infected cells were associated with increased caspase-3 activity and PARP cleavage. The potent and selective apoptotic effects of these drugs suggest that both BMS-345541 and Purvalanol A

  1. Two specific drugs, BMS-345541 and purvalanol A induce apoptosis of HTLV-1 infected cells through inhibition of the NF-kappaB and cell cycle pathways.

    Science.gov (United States)

    Agbottah, Emmanuel; Yeh, Wen-I; Berro, Reem; Klase, Zachary; Pedati, Caitlin; Kehn-Hall, Kyleen; Wu, Weilin; Kashanchi, Fatah

    2008-01-01

    Human T-cell leukemia virus type-1 (HTLV-1) induces adult T-cell leukemia/lymphoma (ATL/L), a fatal lymphoproliferative disorder, and HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP), a chronic progressive disease of the central nervous system after a long period of latent infection. Although the mechanism of transformation and leukemogenesis is not fully elucidated, there is evidence to suggest that the viral oncoprotein Tax plays a crucial role in these processes through the regulation of several pathways including NF-kappaB and the cell cycle pathways. The observation that NF-kappaB, which is strongly induced by Tax, is indispensable for the maintenance of the malignant phenotype of HTLV-1 by regulating the expression of various genes involved in cell cycle regulation and inhibition of apoptosis provides a possible molecular target for these infected cells. To develop potential new therapeutic strategies for HTLV-1 infected cells, in this present study, we initially screened a battery of NF-kappaB and CDK inhibitors (total of 35 compounds) to examine their effects on the growth and survival of infected T-cell lines. Two drugs namely BMS-345541 and Purvalanol A exhibited higher levels of growth inhibition and apoptosis in infected cell as compared to uninfected cells. BMS-345541 inhibited IKKbeta kinase activity from HTLV-1 infected cells with an IC50 (the 50% of inhibitory concentration) value of 50 nM compared to 500 nM from control cells as measured by in vitro kinase assays. The effects of Purvalanol A were associated with suppression of CDK2/cyclin E complex activity as previously shown by us. Combination of both BMS-345541 and Purvalanol A showed a reduced level of HTLV-1 p19 Gag production in cell culture. The apparent apoptosis in these infected cells were associated with increased caspase-3 activity and PARP cleavage. The potent and selective apoptotic effects of these drugs suggest that both BMS-345541 and Purvalanol A, which target

  2. Inhibition of p38 MAP kinase pathway induces apoptosis and prevents Epstein Barr virus reactivation in Raji cells exposed to lytic cycle inducing compounds

    Directory of Open Access Journals (Sweden)

    Di Renzo Livia

    2009-03-01

    Full Text Available Abstract Background EBV lytic cycle activators, such as phorbol esters, anti-immunoglobulin, transforming growth factor β (TGFβ, sodium butyrate, induce apoptosis in EBV-negative but not in EBV-positive Burkitt's lymphoma (BL cells. To investigate the molecular mechanisms allowing EBV-infected cells to be protected, we examined the expression of viral and cellular antiapoptotic proteins as well as the activation of signal transduction pathways in BL-derived Raji cells exposed to lytic cycle inducing agents. Results Our data show that, following EBV activation, the latent membrane protein 1 (LMP1 and the cellular anti-apoptotic proteins MCL-1 and BCL-2 were quickly up-regulated and that Raji cells remained viable even when exposed simultaneously to P(BU2, sodium butyrate and TGFβ. We report here that inhibition of p38 pathway, during EBV activation, led to a three fold increment of apoptosis and largely prevented lytic gene expression. Conclusion These findings indicate that, during the switch from the latent to the lytic phase of EBV infection, p38 MAPK phosphorylation plays a key role both for protecting the host cells from apoptosis as well as for inducing viral reactivation. Because Raji cells are defective for late antigens expression, we hypothesize that the increment of LMP1 gene expression in the early phases of EBV lytic cycle might contribute to the survival of the EBV-positive cells.

  3. 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.

  4. Prognostic implications of molecular and immunohistochemical profiles of the Rb and p53 cell cycle regulatory pathways in primary non-small cell lung carcinoma.

    LENUS (Irish Health Repository)

    Burke, Louise

    2012-02-03

    PURPOSE: Many studies have highlighted the aberrant expression and prognostic significance of individual proteins in either the Rb (particularly cyclin D1, p16INK4A, and pRb) or the p53 (p53 and p21Waf1) pathways in non-small cell lung cancer. We hypothesize that cumulative abnormalities within each and between these pathways would have significant prognostic potential regarding survival. EXPERIMENTAL DESIGN: Our study population consisted of 106 consecutive surgically resected cases of predominantly early-stage non-small cell lung cancer from the National Cancer Institute-Mayo Clinic series, and assessment of proteins involved both immunohistochemical (cyclin D1, p21Waf1, pRb, p16INK4A, and p53) and mutational analysis (p53) in relationship to staging and survival. RESULTS: Cyclin D1 overexpression was noted in 48% of the tumors, p16INK4A negative in 53%, pRb negative in 17%, p53 immunopositive in 50%, p53 mutation frequency in 48%, and p21(Waf1) overexpression in 47%, none with prognostic significance. Cyclin D1 overexpression in pRb-negative tumors revealed a significantly worse prognosis with a mean survival of 2.3 years (P = 0.004). A simultaneous p53 mutation dramatically reduced the mean survival time to 0.9 years (P = 0.007). Cyclin D1 overexpression with either a p53 mutation or a p53 overexpression was also associated with a significantly poorer prognosis (P = 0.0033 and 0.0063, respectively). CONCLUSIONS: Some cumulative abnormalities in the Rb and p53 pathways (e.g., cyclin D1 overexpression and p53 mutations) significantly cooperate to predict a poor prognosis; however, the complexity of the cell cycle protein interaction in any given tumor warrants caution in interpreting survival results when specific protein abnormalities are taken in isolation.

  5. 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

  6. 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...

  7. 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

  8. ZO-2 silencing induces renal hypertrophy through a cell cycle mechanism and the activation of YAP and the mTOR pathway.

    Science.gov (United States)

    Domínguez-Calderón, Alaide; Ávila-Flores, Antonia; Ponce, Arturo; López-Bayghen, Esther; Calderón-Salinas, José-Víctor; Luis Reyes, José; Chávez-Munguía, Bibiana; Segovia, José; Angulo, Carla; Ramírez, Leticia; Gallego-Gutiérrez, Helios; Alarcón, Lourdes; Martín-Tapia, Dolores; Bautista-García, Pablo; González-Mariscal, Lorenza

    2016-05-15

    Renal compensatory hypertrophy (RCH) restores normal kidney function after disease or loss of kidney tissue and is characterized by an increase in organ size due to cell enlargement and not to cell proliferation. In MDCK renal epithelial cells, silencing of the tight junction protein zona occludens 2 (ZO-2 KD) induces cell hypertrophy by two mechanisms: prolonging the time that cells spend at the G1 phase of the cell cycle due to an increase in cyclin D1 level, and augmenting the rate of protein synthesis. The latter is triggered by the nuclear accumulation and increased transcriptional activity of Yes-associated protein (YAP), the main target of the Hippo pathway, which results in decreased expression of phosphatase and tensin homologue. This in turn increased the level of phosphatidylinositol (3,4,5)-triphosphate, which transactivates the Akt/mammalian target of rapamycin pathway, leading to activation of the kinase S6K1 and increased synthesis of proteins and cell size. In agreement, in a rat model of uninephrectomy, RCH is accompanied by decreased expression of ZO-2 and nuclear expression of YAP. Our results reveal a novel role of ZO-2 as a modulator of cell size. PMID:27009203

  9. Two distinct pathways responsible for the loading of CENP-A to centromeres in the fission yeast cell cycle

    OpenAIRE

    Takahashi, Kohta; Takayama, Yuko; Masuda, Fumie; Kobayashi, Yasuyo; Saitoh, Shigeaki

    2005-01-01

    CENP-A is a centromere-specific histone H3 variant that is- essential for faithful chromosome segregation in all eukaryotes thus far investigated. We genetically identified two factors, Ams2 and Mis6, each of which is required for the correct centromere localization of SpCENP-A (Cnp1), the fission yeast homologue of CENP-A. Ams2 is a cell-cycle-regulated GATA factor that localizes on the nuclear chromatin, including on centromeres, during the S phase. Ams2 may be responsible for the replicati...

  10. 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.

  11. 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.

  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. Targeting the cell cycle and the PI3K pathway: a possible universal strategy to reactivate innate tumor suppressor programmes in cancer cells.

    Science.gov (United States)

    David-Pfeuty, Thérèse; Legraverend, Michel; Ludwig, Odile; Grierson, David S

    2010-04-01

    Corruption of the Rb and p53 pathways occurs in virtually all human cancers. This could be because it lends oncogene-bearing cells a surfeit of Cdk activity and growth, enabling them to elaborate strategies to evade tumor-suppressive mechanisms and divide inappropriately. Targeting both Cdk activities and the PI3K pathway might be therefore a potentially universal means to palliate their deficiency in cancer cells. We showed that the killing efficacy of roscovitine and 16 other purines and potentiation of roscovitine-induced apoptosis by the PI3K inhibitor, LY294002, decreased with increasing corruption of the Rb and p53 pathways. Further, we showed that purines differing by a single substitution, which exerted little lethal effect on distant cell types in rich medium, could display widely-differing cytotoxicity profiles toward the same cell types in poor medium. Thus, closely-related compounds targeting similar Cdks may interact with different targets that could compete for their interaction with therapeutically-relevant Cdk targets. In the perspective of clinical development in association with the PI3K pathway inhibitors, it might thus be advisable to select tumor cell type-specific Cdk inhibitors on the basis of their toxicity in cell-culture-based assays performed at a limiting serum concentration sufficient to suppress their interaction with undesirable crossreacting targets whose range and concentration would depend on the cell genotype. PMID:20198331

  14. Platinum-(Ⅳ)-derivative satraplatin induced G2/M cell cycle perturbation via p53-p21waf1/cip1-independent pathway in human colorectal cancer cells

    Institute of Scientific and Technical Information of China (English)

    Murugan KALIMUTHO; Antonella MINUTOLO; Sandro GRELLI; Giorgio FEDERICI; Sergio BERNARDINI

    2011-01-01

    Aim:Platinum-(Ⅳ)-derivative satraplatin represents a new generation of orally available anti-cancer drugs that are under development for the treatment of several cancers.Understanding the mechanisms of cell cycle modulation and apoptosis is necessary to define the mode of action of satraplatin.In this study,we investigate the ability of satraplatin to induce cell cycle perturbation,clonogenicity loss and apoptosis in colorectal cancer (CRC) cells.Methods:CRC cells were treated with satraplatin,and the effects of satraplatin on apoptosis and the cell cycle were evaluated by flow cytometry.Western blot analysis was used to investigate the effects of satraplatin on cell cycle and apoptosis-related proteins.RTqPCR was used to evaluate p53-related mRNA modulation.Results:Satraplatin induced an accumulation of CRC cells predominantly in the G2/M phase.Increased p53 protein expression was observed in the p53 wild-type HCT116 and LoVo cells together with p21waf1/cip1 protein up-regulation.However,p21waf1/cip1 protein accumulation was not observed in the p53 mutant HCT15,HT29,and WiDr cells,even when p53 protein expression was compromised,suggesting that the cell cycle perturbation is p53-p21waf1/cip1 independent.Following a candidate approach,we found an elevated expression of 14-3-3o protein levels in CRC cells,which was independent of the status of p53,further supporting the role of satraplatin in the perturbation of the G2/M cell cycle phase.Moreover,satraplatin treatment induced apoptosis along with Bcl-2 protein down-regulation and abrogated the clonogenic formation of CRC cells in vitro.Conclusion:Collectively,our data suggest that satraplatin induces apoptosis in CRC cells,which is preceded by cell cycle arrest at G2/M due to the effect of 14-3-3σ and in a p53-p21waf1/cip1-independent manner.Taken together,these findings highlight the potential use of satraplatin for CRC treatment.

  15. Induction of G1-phase cell cycle arrest and apoptosis pathway in MDA-MB-231 human breast cancer cells by sulfated polysaccharide extracted from Laurencia papillosa

    OpenAIRE

    Murad, Hossam; Hawat, Mohammad; Ekhtiar, Adnan; ALJAPAWE, ABDULMUNIM; Abbas, Assef; Darwish, Hussein; Sbenati, Oula; Ghannam, Ahmed

    2016-01-01

    Background Marine algae consumption is linked to law cancer incidences in countries that traditionally consume marine products. Hence, Phytochemicals are considered as potential chemo-preventive and chemotherapeutic agents against cancer. We investigated the effects of the algal sulfated polysaccharide extract (ASPE) from the red marine alga L. papillosa on MDA-MB-231 human breast cancer cell line. Methods Flow cytometry analysis was performed to study the cell viability, cell cycle arrest an...

  16. Theaflavin-3, 3'-digallate induces apoptosis and G2 cell cycle arrest through the Akt/MDM2/p53 pathway in cisplatin-resistant ovarian cancer A2780/CP70 cells.

    Science.gov (United States)

    Tu, Youying; Kim, Eunhye; Gao, Ying; Rankin, Gary O; Li, Bo; Chen, Yi Charlie

    2016-06-01

    Ovarian cancer is the most lethal gynecological cancer among women worldwide. Adverse side effects and acquired resistance to conventional platinum based chemotherapy are major impediments in ovarian cancer treatment, and drive the development of more selective anticancer drugs that target cancer-specific defects. In this study, theaflavin-3, 3'-digallate (TF3), the major theaflavin monomer in black tea, exhibited a potent growth inhibitory effect on the cisplatin-resistant ovarian cancer A2780/CP70 cells (IC50, 23.81 µM), and was less cytotoxic to a normal ovarian IOSE‑364 cells (IC50, 59.58 µM) than to the cancer cells. Flow cytometry analysis indicated that TF3 induced preferential apoptosis and G2 cell cycle arrest in A2780/CP70 cells with respect to IOSE‑364 cells. TF3 induced apoptosis through both the intrinsic and extrinsic apoptotic pathways, and caused G2 cell cycle arrest via cyclin B1 in A2780/CP70 cells. The p53 protein played an important role in TF3-induced apoptosis and G2 cell cycle arrest. TF3 might upregulate the p53 expression via the Akt/MDM2 pathway. Our findings help elucidate the mechanisms by which TF3 may contribute to the prevention and treatment of platinum-resistant ovarian cancer. PMID:27082635

  17. Quantitative phosphoproteomics reveals genistein as a modulator of cell cycle and DNA damage response pathways in triple-negative breast cancer cells.

    Science.gov (United States)

    Fang, Yi; Zhang, Qian; Wang, Xin; Yang, Xue; Wang, Xiangyu; Huang, Zhen; Jiao, Yuchen; Wang, Jing

    2016-03-01

    Around one sixth of breast cancer cases are classified as triple-negative breast cancer (TNBC), named after the absence of the expression of estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor 2 (HER2); however, patients with TNBC suffer from poor clinical outcome and shortage of targeted therapy. Genistein, an estrogenic soy isoflavone, shows anticancer effects in TNBC cells such as inducing G2/M cell cycle arrest and apoptosis. However, the underlying mechanism of its anticancer effects is poorly understood and its elucidation can help the development of novel therapeutic strategies for TNBC. In this study, by combining isobaric tag-based TMT labeling with titanium dioxide-based phosphopeptide enrichment, we quantitated 5,445 phosphorylation sites on 2,008 phosphoproteins in the TNBC cell line MDA-MB-231, upon genistein treatment. Our analysis revealed 332 genistein-regulated phosphorylation sites on 226 proteins. Our data show that genistein can regulate several biological processes during the cell cycle, including DNA replication, cohesin complex cleavage, and kinetochore formation. Furthermore, genistein can also activate DNA damage response, including activation of ATR and BRCA1 complex. Overall, our study presents evidence at a phosphoproteomic level that genistein is able to inhibit TNBC cell growth by regulating the cell cycle and DNA damage response in a more complex manner. Our findings help elucidate the mechanisms through which genistein exerts its anticancer effects in TNBC cells. PMID:26783066

  18. Carnosol, a dietary diterpene, displays growth inhibitory effects in human prostate cancer PC3 cells leading to G2-phase cell cycle arrest and targets the 5'-AMP-activated protein kinase (AMPK) pathway

    Science.gov (United States)

    Johnson, Jeremy J.; Syed, Deeba N.; Heren, Chenelle R.; Suh, Yewseok; Adhami, Vaqar M.; Mukhtar, Hasan

    2010-01-01

    Purpose The anti-cancer effect of carnosol was investigated in human prostate cancer PC3 cells. Methods Biochemical analysis and protein array data of carnosol treated PC3 cells were analyzed. Results We evaluated carnosol for its potential anti-cancer properties in the PC3 cells. Using an MTT assay we found that carnosol (10 – 70 µM) decreases cell viability in a time and dose dependent manner. Next, we evaluated the effect of carnosol (20–60 uM) effect using flow cytometry as well as biochemical analysis and found induction of G2-phase cell cycle arrest. To establish a more precise mechanism, we performed a protein array that evaluated 638 proteins involved in cell signaling pathways. The protein array identified 5'-AMP-activated protein kinase (AMPK), a serine/threonine protein kinase involved in the regulation of cellular energy balance as a potential target. Further downstream effects consistent with cancer inhibition included the modulation of the mTOR/HSP70S6k/4E-BP1 pathway. Additionally, we found that carnosol targeted the PI3K/Akt pathway in a dose dependent manner. Conclusions These results suggest that carnosol targets multiple signaling pathways that include the AMPK pathway. The ability of carnosol to inhibit prostate cancer in vitro suggests carnosol may be a novel agent for the management of PCa. PMID:18286356

  19. Interleukin-24 mediates apoptosis in human B-cells through early activation of cell cycle arrest followed by late induction of the mitochondrial apoptosis pathway.

    Science.gov (United States)

    Hadife, Nader; Nemos, Christophe; Frippiat, Jean-Pol; Hamadé, Tala; Perrot, Aurore; Dalloul, Ali

    2013-03-01

    Interleukin (IL)-24 has death-promoting effects on various proliferating cells including B-cells from chronic lymphocytic leukemia (CLL) and germinal center B-cells, but its molecular mechanisms are poorly understood. Using a B-cell differentiation model and mRNA profiling, we found that recombinant (r)IL-24 stimulated genes of the mitochondrial apoptotic pathway (Bax, Bid, Casp8, COX6C, COX7B) after 36 h, whereas the transcription of genes involved in DNA replication and metabolism was inhibited within 6 h. Unexpectedly, insulin-like growth factor 1 (IGF1), a hormone known to promote cell growth, was stimulated by IL-24. Activated B-cells express receptor for IGF1, to which they become sensitized and undergo apoptosis, a mechanism similar in this respect to IL-24-induced cell death. Furthermore, inhibition of the IGF1 pathway reversed the effects of IL-24. IL-24-mediated apoptosis was also antagonized by pifithrin-alpha, an inhibitor of p53 transactivation. Altogether, these results disclose sequential molecular signals generated by IL-24 in activated B-cells. PMID:22860893

  20. Hwanggeumchal sorghum induces cell cycle arrest, and suppresses tumor growth and metastasis through Jak2/STAT pathways in breast cancer xenografts.

    Directory of Open Access Journals (Sweden)

    Jin Hee Park

    Full Text Available BACKGROUND: Cancer is one of the highly virulent diseases known to humankind with a high mortality rate. Breast cancer is the most common cancer in women worldwide. Sorghum is a principal cereal food in many parts of the world, and is critical in folk medicine of Asia and Africa. In the present study, we analyzed the effects of HSE in metastatic breast cancer. METHODOLOGY/PRINCIPAL FINDINGS: Preliminary studies conducted on MDA-MB 231 and MCF-7 xenograft models showed tumor growth suppression by HSE. Western blotting studies conducted both in vivo and in vitro to check the effect of HSE in Jak/STAT pathways. Anti-metastatic effects of HSE were confirmed using both MDA-MB 231 and MCF-7 metastatic animal models. These studies showed that HSE can modulate Jak/STAT pathways, and it hindered the STAT5b/IGF-1R and STAT3/VEGF pathways not only by down-regulating the expression of these signal molecules and but also by preventing their phosphorylation. The expression of angiogenic factors like VEGF, VEGF-R2 and cell cycle regulators like cyclin D, cyclin E, and pRb were found down-regulated by HSE. In addition, it also targets Brk, p53, and HIF-1α for anti-cancer effects. HSE induced G1 phase arrest and migration inhibition in MDA-MB 231 cells. The metastasis of breast cancer to the lungs also found blocked by HSE in the metastatic animal model. CONCLUSIONS/SIGNIFICANCE: Usage of HS as a dietary supplement is an inexpensive natural cancer therapy, without any side effects. We strongly recommend the use of HS as an edible therapeutic agent as it possesses tumor suppression, migration inhibition, and anti-metastatic effects on breast cancer.

  1. Antagonism between curcumin and the topoisomerase II inhibitor etoposide: A study of DNA damage, cell cycle regulation and death pathways

    OpenAIRE

    Saleh, Ekram M; El-Awady, Raafat A.; Eissa, Nadia A.; Abdel-Rahman, Wael M.

    2012-01-01

    The use of combinations of chemotherapy and natural products has recently emerged as a new method of cancer therapy, relying on the capacity of certain natural compounds to trigger cell death with low doses of chemotherapeutic agents and few side effects. The current study aims to evaluate the modulatory effects of curcumin (CUR), Nigella sativa (NS) and taurine on etoposide (ETP) cytotoxicity in a panel of cancer cell lines and to identify their underlying mechanisms.

  2. ETME, a novel β-elemene derivative, synergizes with arsenic trioxide in inducing apoptosis and cell cycle arrest in hepatocarcinoma cells via a p53-dependent pathway

    Directory of Open Access Journals (Sweden)

    Zhiying Yu

    2014-12-01

    Full Text Available Arsenic trioxide (ATO has been identified as an effective treatment for acute promyelocytic leukemia (APL but is much less effective against solid tumors such as hepatocellular carcinoma (HCC. In the search for ways to enhance its therapeutic efficacy against solid tumors, we have examined its use in combination with a novel derivative of β-elemene, N-(β-elemene-13-yltryptophan methyl ester (ETME. Here we report the effects of the combination on cell viability, apoptosis, the cell cycle and mitochondria membrane potential (MMP in HCC SMMC-7721 cells. We found that the two compounds acted synergistically to enhance antiproliferative activity and apoptosis. The combination also decreased the MMP, down-regulated Bcl-2 and pro-proteins of the caspase family, and up-regulated Bax and BID, all of which were reversed by the p53 inhibitor, pifithrin-α. In addition, the combination induced cell cycle arrest at the G2/M phase and reduced tumor volume and weight in an xenograft model of nude mice. Overall, the results suggest that ETME in combination with ATO may be useful in the treatment of HCC patients particularly those unresponsive to ATO alone.

  3. Crude extract of Rheum palmatum L. Induces cell cycle arrest S phase and apoptosis through mitochondrial-dependent pathways in U-2 OS human osteosarcoma cells.

    Science.gov (United States)

    Lin, Chin-Chung; Lee, Ming-Huei; Lin, Ju-Hwa; Lin, Meng-Liang; Chueh, Fu-Shin; Yu, Chien-Chih; Lin, Jing-Pin; Chou, Yu-Cheng; Hsu, Shu-Chun; Chung, Jing-Gung

    2016-08-01

    Cancer is the second cause of death in children. Osteosarcoma is the most common primary malignancy of solid bone cancer primarily affecting adolescents and young adults. In the Chinese population, the crude extract of Rheum palmatum L. (CERP) has been used for treating different diseases, including SARS, rheumatoid arthritis, coxsackievirus B3, and human colon cancer cell, pancreatic cancer. There are no reports on CERP and human osteosarcoma cells. The present study examined effects of CERP on cytotoxicity including cell cycle distribution and cell death (apoptosis) in U-2 OS human osteosarcoma cells. CERP significantly induced S phase arrest in U-2 OS cells in a dose-dependent. CERP produced DNA damage and DNA condensation. Other effects of CERP were stimulation of ROS and Ca(2+) , mitochondria impairment, and activation of caspase-3, -8, and -9. CERP increased the levels of Bax, Bak, Bad, cyclin B, Fas, PARP, GRP78, GADD153, AIF, Endo G, Calpain-2, p21, and p27, but decreased the levels of Bcl-2, BCL-X, XIAP, Akt, CDC25A, CDK2, Cyclin A, and Cyclin E of U-2 OS cells. It was also observed that CERP promoted the expression of AIF, Endo G, GADD153, and cytochrome c. These results indicate that CERP has anticancer effects in vitro and provide the foundation for in vivo studies of animal models of osteosarcoma. © 2015 Wiley Periodicals, Inc. Environ Toxicol 31: 957-969, 2016. PMID:25689151

  4. Flavokawain C Inhibits Cell Cycle and Promotes Apoptosis, Associated with Endoplasmic Reticulum Stress and Regulation of MAPKs and Akt Signaling Pathways in HCT 116 Human Colon Carcinoma Cells.

    Directory of Open Access Journals (Sweden)

    Chung-Weng Phang

    Full Text Available Flavokawain C (FKC is a naturally occurring chalcone which can be found in Kava (Piper methysticum Forst root. The present study evaluated the effect of FKC on the growth of various human cancer cell lines and the underlying associated mechanisms. FKC showed higher cytotoxic activity against HCT 116 cells in a time- and dose-dependent manner in comparison to other cell lines (MCF-7, HT-29, A549 and CaSki, with minimal toxicity on normal human colon cells. The apoptosis-inducing capability of FKC on HCT 116 cells was evidenced by cell shrinkage, chromatin condensation, DNA fragmentation and increased phosphatidylserine externalization. FKC was found to disrupt mitochondrial membrane potential, resulting in the release of Smac/DIABLO, AIF and cytochrome c into the cytoplasm. Our results also revealed that FKC induced intrinsic and extrinsic apoptosis via upregulation of the levels of pro-apoptotic proteins (Bak and death receptors (DR5, while downregulation of the levels of anti-apoptotic proteins (XIAP, cIAP-1, c-FlipL, Bcl-xL and survivin, resulting in the activation of caspase-3, -8 and -9 and cleavage of poly(ADP-ribose polymerase (PARP. FKC was also found to cause endoplasmic reticulum (ER stress, as suggested by the elevation of GADD153 protein after FKC treatment. After the cells were exposed to FKC (60μM over 18hrs, there was a substantial increase in the phosphorylation of ERK 1/2. The expression of phosphorylated Akt was also reduced. FKC also caused cell cycle arrest in the S phase in HCT 116 cells in a time- and dose-dependent manner and with accumulation of cells in the sub-G1 phase. This was accompanied by the downregulation of cyclin-dependent kinases (CDK2 and CDK4, consistent with the upregulation of CDK inhibitors (p21Cip1 and p27Kip1, and hypophosphorylation of Rb.

  5. Decreased radioiodine uptake of FRTL-5 cells after 131I incubation in vitro: molecular biological investigations indicate a cell cycle-dependent pathway

    International Nuclear Information System (INIS)

    In radioiodine therapy the ''stunning phenomenon'' is defined as a reduction of radioiodine uptake after diagnostic application of 131I. In the current study, we established an in vitro model based on the ''Fisher rat thyrocyte cell line no. 5'' (FRTL-5) to investigate the stunning. TSH-stimulated FRTL-5 cells were incubated with 131I. Time-dependent 131I uptake and the viability of FRTL-5 cells were evaluated at 4-144 h after radioiodine application. All data was corrected for number of viable cells, half life and 131I concentration. Sodium iodide symporter (NIS) and the housekeeping gene (β-actin, GAPDH) levels were quantified by quantitative polymerase chain reaction (qPCR). Additionally, immunohistochemical staining (IHC) of NIS on the cell membrane was carried out. FRTL-5 monolayer cell cultures showed a specific maximum uptake of 131I 24-48 h after application. Significantly decreased 131I uptake values were observed after 72-144 h. The decrease in radioiodine uptake was correlated with decreasing mRNA levels of NIS and housekeeping genes. In parallel, unlike in controls, IHC staining of NIS on FRTL-5 cells declined significantly after 131I long-term incubation. It could be demonstrated that during 131I incubation of FRTL-5 cells, radioiodine uptake decreased significantly. Simultaneously decreasing levels of NIS mRNA and protein expression suggest a NIS-associated mechanism. Since mRNA levels of housekeeping genes decreased, too, the reduced NIS expression might be provoked by a cell cycle arrest. Our investigations recommend the FRTL-5 model as a valuable tool for further molecular biological investigations of the stunning phenomenon. (orig.)

  6. 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...

  7. Loss of DDB1 Leads to Transcriptional p53 Pathway Activation in Proliferating Cells, Cell Cycle Deregulation, and Apoptosis in Zebrafish Embryos

    Science.gov (United States)

    Hu, Zhilian; Holzschuh, Jochen; Driever, Wolfgang

    2015-01-01

    DNA damage-binding protein 1 (DDB1) is a large subunit of the heterodimeric DDB complex that recognizes DNA lesions and initiates the nucleotide excision repair process. DDB1 is also a component of the CUL4 E3 ligase complex involved in a broad spectrum of cellular processes by targeted ubiquitination of key regulators. Functions of DDB1 in development have been addressed in several model organisms, however, are not fully understood so far. Here we report an ENU induced mutant ddb1 allele (ddb1m863) identified in zebrafish (Danio rerio), and analyze its effects on development. Zebrafish ddb1 is expressed broadly, both maternally and zygotically, with enhanced expression in proliferation zones. The (ddb1m863 mutant allele affects the splice acceptor site of exon 20, causing a splicing defect that results in truncation of the 1140 amino acid protein after residue 800, lacking part of the β-propeller domain BPC and the C-terminal helical domain CTD. ddb1m863 zygotic mutant embryos have a pleiotropic phenotype, including smaller and abnormally shaped brain, head skeleton, eyes, jaw, and branchial arches, as well as reduced dopaminergic neuron groups. However, early forming tissues develop normally in zygotic ddb1m863 mutant embryos, which may be due to maternal rescue. In ddb1m863 mutant embryos, pcna-expressing proliferating cell populations were reduced, concurrent with increased apoptosis. We also observed a concomitant strong up-regulation of transcripts of the tumor suppressor p53 (tp53) and the cell cycle inhibitor cdkn1a (p21a/bCIP1/WAF1) in proliferating tissues. In addition, transcription of cyclin genes ccna2 and ccnd1 was deregulated in ddb1m863 mutants. Reduction of p53 activity by anti-sense morpholinos alleviated the apoptotic phenotype in ddb1m863 mutants. These results imply that Ddb1 may be involved in maintaining proper cell cycle progression and viability of dividing cells during development through transcriptional mechanisms regulating genes

  8. Biological and molecular mechanisms of sulfur mustard analogue-induced toxicity in JB6 and HaCaT cells: possible role of ataxia telangiectasia-mutated/ataxia telangiectasia-Rad3-related cell cycle checkpoint pathway.

    Science.gov (United States)

    Tewari-Singh, Neera; Gu, Mallikarjuna; Agarwal, Chapla; White, Carl W; Agarwal, Rajesh

    2010-06-21

    Effective medical treatment and preventive measures for chemical warfare agent sulfur mustard (HD)-caused incapacitating skin toxicity are lacking, because of limited knowledge of its mechanism of action. The proliferating basal epidermal cells are primary major sites of attack during HD-caused skin injury. Therefore, employing mouse JB6 and human HaCaT epidermal cells, here, we investigated the molecular mechanism of HD analogue 2-chloroethyl ethyl sulfide (CEES)-induced skin cytotoxicity. As compared to the control, up to 1 mM CEES treatment of these cells for 2, 4, and 24 h caused dose-dependent decreases in cell viability and proliferation as measured by DNA synthesis, together with S and G2-M phase arrest in cell cycle progression. Mechanistic studies showed phosphorylation of DNA damage sensors and checkpoint kinases, ataxia telangiectasia-mutated (ATM) at ser1981 and ataxia telangiectasia-Rad3-related (ATR) at ser428 within 30 min of CEES exposure, and modulation of S and G2-M phase-associated cell cycle regulatory proteins, which are downstream targets of ATM and ATR kinases. Hoechst-propidium iodide staining demonstrated that CEES-induced cell death was both necrotic and apoptotic in nature, and the latter was induced at 4 and 24 h of CEES treatment in HaCaT and JB6 cells, respectively. An increase in caspase-3 activity and both caspase-3 and poly(ADP-ribose)polymerase (PARP) cleavage coinciding with CEES-caused apoptosis in both cell lines suggested the involvement of the caspase pathway. Together, our findings suggest a DNA-damaging effect of CEES that activates ATM/ATR cell cycle checkpoint signaling as well as caspase-PARP pathways, leading to cell cycle arrest and apoptosis/necrosis in both JB6 and HaCaT cells. The identified molecular targets, quantitative biomarkers, and epidermal cell models in this study have the potential and usefulness in rapid development of effective prophylactic and therapeutic interventions against HD-induced skin toxicity

  9. MODEL-BASED IDENTIFICATION AND ADAPTIVE CONTROL OF THE CORE MODULE IN A TYPICAL CELL CYCLE PATHWAY VIA NETWORK AND SYSTEM CONTROL THEORIES

    OpenAIRE

    BINHUA TANG; LI HE; QING JING; BAIRONG SHEN

    2009-01-01

    The loss of cell cycle control is often associated with cancers and other different diseases. With the accumulation of omics data, the network for molecule interactions in the cell cycle process will become much clearer. The identification of the crucial modules in a giant network and investigation of inherent control relations are very important to the understanding of the molecular mechanisms of diseases for new drug design. The paper proposes novel techniques in analyzing such core regulat...

  10. Life cycle analysis of transportation fuel pathways

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2012-02-24

    The purpose of this work is to improve the understanding of the concept of life cycle analysis (LCA) of transportation fuels and some of its pertinent issues among non-technical people, senior managers, and policy makers. This work should provide some guidance to nations considering LCA-based policies and to people who are affected by existing policies or those being developed. While the concept of employing LCA to evaluate fuel options is simple and straightforward, the act of putting the concept into practice is complex and fraught with issues. Policy makers need to understand the limitations inherent in carrying out LCA work for transportation fuel systems. For many systems, even those that have been employed for a 100 years, there is a lack of sound data on the performance of those systems. Comparisons between systems should ideally be made using the same tool, so that differences caused by system boundaries, allocation processes, and temporal issues can be minimized (although probably not eliminated). Comparing the results for fuel pathway 1 from tool A to those of fuel system 2 from tool B introduces significant uncertainty into the results. There is also the question of the scale of system changes. LCA will give more reliable estimates when it is used to examine small changes in transportation fuel pathways than when used to estimate large scale changes that replace current pathways with completely new pathways. Some LCA tools have been developed recently primarily for regulatory purposes. These tools may deviate from ISO principles in order to facilitate simplicity and ease of use. In a regulatory environment, simplicity and ease of use are worthy objectives and in most cases there is nothing inherently wrong with this approach, particularly for assessing relative performance. However, the results of these tools should not be confused with, or compared to, the results that are obtained from a more complex and rigorous ISO compliant LCA. It should be

  11. Benzophenone-1 stimulated the growth of BG-1 ovarian cancer cells by cell cycle regulation via an estrogen receptor alpha-mediated signaling pathway in cellular and xenograft mouse models

    International Nuclear Information System (INIS)

    Highlights: ► BP-1 induced cell growth was reversed by an ER antagonist in BG-1 cells. ► BP-1 up-regulated the mRNA expression of cyclin D1. ► Up-regulation of cyclin D1 by BP-1 was reversed by an ER antagonist. ► BP-1 is a potential endocrine disruptor that exerts estrogenic effects. - Abstract: 2,4-Dihydroxybenzophenone (benzophenone-1; BP-1) is an UV stabilizer primarily used to prevent polymer degradation and deterioration in quality due to UV irradiation. Recently, BP-1 has been reported to bioaccumulate in human bodies by absorption through the skin and has the potential to induce health problems including endocrine disruption. In the present study, we examined the xenoestrogenic effect of BP-1 on BG-1 human ovarian cancer cells expressing estrogen receptors (ERs) and relevant xenografted animal models in comparison with 17-β estradiol (E2). In in vitro cell viability assay, BP-1 (10−8–10−5 M) significantly increased BG-1 cell growth the way E2 did. The mechanism underlying the BG-1 cell proliferation was proved to be related with the up-regulation of cyclin D1, a cell cycle progressor, by E2 or BP-1. Both BP-1 and E2 induced cell growth and up-regulation of cyclin D1 were reversed by co-treatment with ICI 182,780, an ER antagonist, suggesting that BP-1 may mediate the cancer cell proliferation via an ER-dependent pathway like E2. On the other hand, the expression of p21, a regulator of cell cycle progression at G1 phase, was not altered by BP-1 though it was down-regulated by E2. In xenograft mouse models transplanted with BG-1 cells, BP-1 or E2 treatment significantly increased the tumor mass formation compared to a vehicle (corn oil) within 8 weeks. In histopathological analysis, the tumor sections of E2 or BP-1 group displayed extensive cell formations with high density and disordered arrangement, which were supported by the increased number of BrdUrd positive nuclei and the over-expression of cyclin D1 protein. Taken together, these

  12. Rosa hybrida extract suppresses vascular smooth muscle cell responses by the targeting of signaling pathways, cell cycle regulation and matrix metalloproteinase-9 expression.

    Science.gov (United States)

    Lee, Se-Jung; Won, Se Yeon; Park, Sung Lyea; Song, Jun-Hui; Noh, Dae-Hwa; Kim, Hong-Man; Yin, Chang Shik; Kim, Wun-Jae; Moon, Sung-Kwon

    2016-04-01

    The pharmacological effects of Rosa hybrida are well known in the cosmetics industry. However, the role of Rosa hybrida in cardiovascular biology had not previously been investigated, to the best of our knowledge. The aim of the present study was to elucidate the effect of water extract of Rosa hybrida (WERH) on platelet‑derived growth factor (PDGF)-stimulated vascular smooth muscle cells (VSMCs). VSMC proliferation, which was stimulated by PDGF, was inhibited in a non-toxic manner by WERH treatment, which also diminished the phosphorylation of extracellular signal-regulated kinase 1/2 (ERK1/2) and AKT. Treatment with WERH also induced G1-phase cell cycle arrest, which was due to the decreased expression of cyclins and cyclin-dependent kinases (CDKs), and induced p21WAF1 expression in PDGF-stimulated VSMCs. Moreover, WERH treatment suppressed the migration and invasion of VSMCs stimulated with PDGF. Treatment with WERH abolished the expression of matrix metalloproteinase-9 (MMP-9) and decreased the binding activity of nuclear factor-κB (NF-κB), activator protein-1 (AP-1), and specificity protein 1 (Sp1) motifs in PDGF-stimulated VSMCs. WERH treatment inhibited the proliferation of PDGF‑stimulated VSMCs through p21WAF1‑mediated G1-phase cell cycle arrest, by decreasing the kinase activity of cyclin/CDK complexes. Furthermore, WERH suppressed the PDGF-induced phosphorylation of ERK1/2 and AKT in VSMCs. Finally, treatment with WERH impeded the migration and invasion of VSMCs stimulated by PDGF by downregulating MMP-9 expression and a reduction in NF-κB, AP-1 and Sp1 activity. These results provide new insights into the effects of WERH on PDGF-stimulated VSMCs, and we suggest that WERH has the potential to act as a novel agent for the prevention and/or treatment of vascular diseases. PMID:26935151

  13. c-Src regulates cell cycle proteins expression through protein kinase B/glycogen synthase kinase 3 beta and extracellular signal-regulated kinases 1/2 pathways in MCF-7 cells

    Institute of Scientific and Technical Information of China (English)

    Xiang Liu; Liying Du; Renqing Feng

    2013-01-01

    We have demonstrated that c-Src suppression inhibited the epithelial to mesenchymal transition in human breast cancer cells.Here,we investigated the role of c-Src on the cell cycle progression using siRNAs and small molecule inhibitor 4-amino-5-(4-chlorophenyl)-7-(t-butyl)pyrazolo [3,4-d]pyrimidine (PP2).Western blot analysis demonstrated the downregulation of cyclin D1 and cyclin E and up-regulation of p27 Kip1 after c-Src suppression by PP2.Incubation of cells in the presence of PP2 significantly blocked the phosphorylation of extracellular signal-regulated kinases 1/2 (ERK1/2),protein kinase B (AKT),and glycogen synthase kinase 3 beta (GSK3β).Specific pharmacological inhibitors of MEK1/2/ERK1/2 and phosphatidylinositide 3-kinase/AKTpathways were used to demonstrate the relationship between the signal cascade and cell cycle proteins expression.The expression of cyclin D1 and cyclin E were decreased after inhibition of ERK1/2 or AKT activity,whereas the p27 Kip1 expression was increased.In addition,knockdown of c-Src by siRNAs reduced cell proliferation and phosphorylation of ERK1/2,AKT,and GSK3β.After c-Src depletion by siRNAs,we observed significant down-regulation of cyclin D1 and cyclin E,and up-regulation of p27 Kip1.These results suggest that c-Src suppression by PP2 or siRNAs may regulate the progression of cell cycle through AKT/GSK3β and ERK1/2 pathways.

  14. Ferulago angulata activates intrinsic pathway of apoptosis in MCF-7 cells associated with G1 cell cycle arrest via involvement of p21/p27

    Directory of Open Access Journals (Sweden)

    Karimian H

    2014-09-01

    and the quantitative polymerase chain reaction analysis of MCF-7 cells after treatment with FALHE revealed an upregulation of Bax and a downregulation of Bcl-2 proteins. These findings proposed that FALHE suppressed the proliferation of MCF-7 cells via cell cycle arrest and the induction of apoptosis through intrinsic pathway. Keywords: Ferulago angulata, apoptosis, cancer, MCF-7, cell cycle, p21/p27

  15. Phenformin Induces Cell Cycle Change, Apoptosis, and Mesenchymal-Epithelial Transition and Regulates the AMPK/mTOR/p70s6k and MAPK/ERK Pathways in Breast Cancer Cells.

    Science.gov (United States)

    Liu, Zhao; Ren, Lidong; Liu, Chenghao; Xia, Tiansong; Zha, Xiaoming; Wang, Shui

    2015-01-01

    Breast cancer remains a world-wide challenge, and additional anti-cancer therapies are still urgently needed. Emerging evidence has demonstrated the potent anti-tumor effect of biguanides, among which phenformin was reported to potentially be a more active anti-cancer agent than metformin. However, little attention has been given to the role of phenformin in breast cancer. In this study, we reveal the role of phenformin in cell death of the MCF7, ZR-75-1, MDA-MB-231 and SUM1315 breast cancer cell lines. The respective IC50 values of phenformin in MCF7, ZR-75-1, MDA-MB-231 and SUM1315 cells were 1.184±0.045 mM, 0.665±0.007 mM, 2.347±0.010 mM and 1.885±0.015 mM (mean± standard error). Phenformin induced cell cycle change and apoptosis in breast cancer cells via the AMPK/mTOR/p70s6k and MAPK/ERK pathways. Interestingly, phenformin induced MET (mesenchymal-epithelial transition) and decreased the migration rate in breast cancer cell lines. Furthermore, our results suggest that phenformin inhibits breast cancer cell metastasis after intracardiac injection into nude mice. Taken together, our study further confirms the potential benefit of phenformin in breast cancer treatment and provides novel mechanistic insight into its anti-cancer activity in breast cancer. PMID:26114294

  16. Phenformin Induces Cell Cycle Change, Apoptosis, and Mesenchymal-Epithelial Transition and Regulates the AMPK/mTOR/p70s6k and MAPK/ERK Pathways in Breast Cancer Cells.

    Directory of Open Access Journals (Sweden)

    Zhao Liu

    Full Text Available Breast cancer remains a world-wide challenge, and additional anti-cancer therapies are still urgently needed. Emerging evidence has demonstrated the potent anti-tumor effect of biguanides, among which phenformin was reported to potentially be a more active anti-cancer agent than metformin. However, little attention has been given to the role of phenformin in breast cancer. In this study, we reveal the role of phenformin in cell death of the MCF7, ZR-75-1, MDA-MB-231 and SUM1315 breast cancer cell lines. The respective IC50 values of phenformin in MCF7, ZR-75-1, MDA-MB-231 and SUM1315 cells were 1.184±0.045 mM, 0.665±0.007 mM, 2.347±0.010 mM and 1.885±0.015 mM (mean± standard error. Phenformin induced cell cycle change and apoptosis in breast cancer cells via the AMPK/mTOR/p70s6k and MAPK/ERK pathways. Interestingly, phenformin induced MET (mesenchymal-epithelial transition and decreased the migration rate in breast cancer cell lines. Furthermore, our results suggest that phenformin inhibits breast cancer cell metastasis after intracardiac injection into nude mice. Taken together, our study further confirms the potential benefit of phenformin in breast cancer treatment and provides novel mechanistic insight into its anti-cancer activity in breast cancer.

  17. Kaposi sarcoma herpes virus latency associated nuclear antigen protein release the G2/M cell cycle blocks by modulating ATM/ATR mediated checkpoint pathway.

    Directory of Open Access Journals (Sweden)

    Amit Kumar

    Full Text Available The Kaposi's sarcoma-associated herpesvirus infects the human population and maintains latency stage of viral life cycle in a variety of cell types including cells of epithelial, mesenchymal and endothelial origin. The establishment of latent infection by KSHV requires the expression of an unique repertoire of genes among which latency associated nuclear antigen (LANA plays a critical role in the replication of the viral genome. LANA regulates the transcription of a number of viral and cellular genes essential for the survival of the virus in the host cell. The present study demonstrates the disruption of the host G2/M cell cycle checkpoint regulation as an associated function of LANA. DNA profile of LANA expressing human B-cells demonstrated the ability of this nuclear antigen in relieving the drug (Nocodazole induced G2/M checkpoint arrest. Caffeine suppressed nocodazole induced G2/M arrest indicating involvement of the ATM/ATR. Notably, we have also shown the direct interaction of LANA with Chk2, the ATM/ATR signalling effector and is responsible for the release of the G2/M cell cycle block.

  18. An Ingenol Derived from Euphorbia kansui Induces Hepatocyte Cytotoxicity by Triggering G0/G1 Cell Cycle Arrest and Regulating the Mitochondrial Apoptosis Pathway in Vitro.

    Science.gov (United States)

    Yan, Xiaojing; Zhang, Li; Cao, Yudan; Yao, Weifeng; Tang, Yuping; Ding, Anwei

    2016-01-01

    Natural product lingenol, a purified diterpenoid compound derived from the root of Euphorbia kansui, exerts serious hepatotoxicity; however, the molecular mechanisms remain to be defined. In the present study, cell counting Kit-8 (CCK-8), inverted phase contrast microscope and flow cytometry were used to demonstrate that lingenol significantly inhibited L-O2 cells proliferation, and induced cell cycle arrest and apoptosis. Moreover, the results investigated that lingenol markedly disrupted mitochondrial functions by high content screening (HCS). In addition, the up-regulation of cytochrome c, AIF and Apaf-1 and activation of caspases were found in L-O2 cells detected by Western blotting and ELISA assay, which was required for lingenol activation of cytochrome c-mediated caspase cascades and AIF-mediated DNA damage. Mechanistic investigations revealed that lingenol significantly down-regulated the Bcl-2/Bax ratio and enhanced the reactive oxygen species (ROS) in L-O2 cells. These data collectively indicated that lingenol modulation of ROS and Bcl-2/Bax ratio led to cell cycle arrest and mitochondrial-mediated apoptosis in L-O2 cells in vitro. All of these results will be helpful to reveal the hepatotoxicity mechanism of Euphorbia kansui and to effectively guide safer and better clinical application of this herb. PMID:27338329

  19. An Ingenol Derived from Euphorbia kansui Induces Hepatocyte Cytotoxicity by Triggering G0/G1 Cell Cycle Arrest and Regulating the Mitochondrial Apoptosis Pathway in Vitro

    Directory of Open Access Journals (Sweden)

    Xiaojing Yan

    2016-06-01

    Full Text Available Natural product lingenol, a purified diterpenoid compound derived from the root of Euphorbia kansui, exerts serious hepatotoxicity; however, the molecular mechanisms remain to be defined. In the present study, cell counting Kit-8 (CCK-8, inverted phase contrast microscope and flow cytometry were used to demonstrate that lingenol significantly inhibited L-O2 cells proliferation, and induced cell cycle arrest and apoptosis. Moreover, the results investigated that lingenol markedly disrupted mitochondrial functions by high content screening (HCS. In addition, the up-regulation of cytochrome c, AIF and Apaf-1 and activation of caspases were found in L-O2 cells detected by Western blotting and ELISA assay, which was required for lingenol activation of cytochrome c-mediated caspase cascades and AIF-mediated DNA damage. Mechanistic investigations revealed that lingenol significantly down-regulated the Bcl-2/Bax ratio and enhanced the reactive oxygen species (ROS in L-O2 cells. These data collectively indicated that lingenol modulation of ROS and Bcl-2/Bax ratio led to cell cycle arrest and mitochondrial-mediated apoptosis in L-O2 cells in vitro. All of these results will be helpful to reveal the hepatotoxicity mechanism of Euphorbia kansui and to effectively guide safer and better clinical application of this herb.

  20. Inhibition of Aurora-A kinase induces cell cycle arrest in epithelial ovarian cancer stem cells by affecting NFκB pathway

    OpenAIRE

    Chefetz, Ilana; Holmberg, Jennie C.; Alvero, Ayesha B.; Visintin, Irene; Mor, Gil

    2011-01-01

    Recurrent ovarian cancer is resistant to conventional chemotherapy. A sub-population of ovarian cancer cells, the epithelial ovarian cancer stem cells (EOC stem cells) have stemness properties, constitutive NFκB activity, and represent the chemoresistant population. Currently, there is no effective treatment that targets these cells. Aurora-A kinase (Aurora-A) is associated with tumor initiation and progression and is overexpressed in numerous malignancies. The aim of this study is to determi...

  1. Deoxycholic Acid and Selenium Metabolite Methylselenol Exert Common and Distinct Effects on Cell Cycle, Apoptosis, and MAP Kinase Pathway in HCT116 Human Colon Cancer Cells

    Science.gov (United States)

    Bile acid deoxycholic acid (DCA) is a known tumor promoter in colon tumor development. The cell growth inhibition induced by DCA may cause compensatory hyperproliferation of colonic epithelial cells and provide selection for subpopulations of cells resistant to DCA’s inhibitory effect. These survivi...

  2. Lewis y Regulate Cell Cycle Related Factors in Ovarian Carcinoma Cell RMG-I in Vitro via ERK and Akt Signaling Pathways

    OpenAIRE

    Shulan Zhang; Qing Liu; Yingying Hao; Rui Hou; Bei Lin; Shuice Liu; Juanjuan Liu; Masao Iwamori; Dawo Liu

    2012-01-01

    Objective: To investigate the effect of Lewis y overexpression on the expression of proliferation-related factors in ovarian cancer cells. Methods: mRNA levels of cyclins, CDKs, and CKIs were measured in cells before and after transfection with the α1,2-fucosyltransferase gene by real-time PCR, and protein levels of cyclins, CDKs and CKIs were determined in cells before and after gene transfection by Western blot. Results: Lewis y overexpression led to an increase in both mRNA and protein exp...

  3. MicroRNA-302/367 Cluster Governs hESC Self-Renewal by Dually Regulating Cell Cycle and Apoptosis Pathways

    Directory of Open Access Journals (Sweden)

    Zhonghui Zhang

    2015-04-01

    Full Text Available miR-302/367 is the most abundant miRNA cluster in human embryonic stem cells (hESCs and can promote somatic cell reprogramming. However, its role in hESCs remains poorly understood. Here, we studied functional roles of the endogenous miR-302/367 cluster in hESCs by employing specific TALE-based transcriptional repressors. We revealed that miR-302/367 cluster dually regulates hESC cell cycle and apoptosis in dose-dependent manner. Gene profiling and functional studies identified key targets of the miR-302/367 cluster in regulating hESC self-renewal and apoptosis. We demonstrate that in addition to its role in cell cycle regulation, miR-302/367 cluster conquers apoptosis by downregulating BNIP3L/Nix (a BH3-only proapoptotic factor and upregulating BCL-xL expression. Furthermore, we show that butyrate, a natural compound, upregulates miR-302/367 cluster expression and alleviates hESCs from apoptosis induced by knockdown of miR-302/367 cluster. In summary, our findings provide new insights in molecular mechanisms of how miR-302/367 cluster regulates hESCs.

  4. 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...

  5. 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.

  6. Differential effects of deoxycholic acid versus selenium metabolite methylselenol on cell cycle, apoptosis, and MAP kinase pathway in HCT116 human colon cancer cells

    Science.gov (United States)

    Introduction: A typical part of the Western diet is a high fat intake that leads to increased levels of fecal bile acids, and these bile acids, primarily deoxycholic acid (DCA) in humans, have been believed to be tumor promoters of colon cancer. The cell growth inhibition induced by bile acid deoxyc...

  7. 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.

  8. Regulation of Cell Wall Biogenesis in Saccharomyces cerevisiae: The Cell Wall Integrity Signaling Pathway

    OpenAIRE

    Levin, David E.

    2011-01-01

    The yeast cell wall is a strong, but elastic, structure that is essential not only for the maintenance of cell shape and integrity, but also for progression through the cell cycle. During growth and morphogenesis, and in response to environmental challenges, the cell wall is remodeled in a highly regulated and polarized manner, a process that is principally under the control of the cell wall integrity (CWI) signaling pathway. This pathway transmits wall stress signals from the cell surface to...

  9. Genetic Networks Lead and Follow Tumor Development: MicroRNA Regulation of Cell Cycle and Apoptosis in the p53 Pathways

    Directory of Open Access Journals (Sweden)

    Kurataka Otsuka

    2014-01-01

    Full Text Available During the past ten years, microRNAs (miRNAs have been shown to play a more significant role in the formation and progression of cancer diseases than previously thought. With an increase in reports about the dysregulation of miRNAs in diverse tumor types, it becomes more obvious that classic tumor-suppressive molecules enter deep into the world of miRNAs. Recently, it has been demonstrated that a typical tumor suppressor p53, known as the guardian of the genome, regulates some kinds of miRNAs to contribute to tumor suppression by the induction of cell-cycle arrest and apoptosis. Meanwhile, miRNAs directly/indirectly control the expression level and activity of p53 to fine-tune its functions or to render p53 inactive, indicating that the interplay between p53 and miRNA is overly complicated. The findings, along with current studies, will underline the continuing importance of understanding this interlocking control system for future therapeutic strategies in cancer treatment and prevention.

  10. 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...

  11. Pathway-specific differences between tumor cell lines and normal and tumor tissue cells

    Directory of Open Access Journals (Sweden)

    Tozeren Aydin

    2006-11-01

    Full Text Available Abstract Background Cell lines are used in experimental investigation of cancer but their capacity to represent tumor cells has yet to be quantified. The aim of the study was to identify significant alterations in pathway usage in cell lines in comparison with normal and tumor tissue. Methods This study utilized a pathway-specific enrichment analysis of publicly accessible microarray data and quantified the gene expression differences between cell lines, tumor, and normal tissue cells for six different tissue types. KEGG pathways that are significantly different between cell lines and tumors, cell lines and normal tissues and tumor and normal tissue were identified through enrichment tests on gene lists obtained using Significance Analysis of Microarrays (SAM. Results Cellular pathways that were significantly upregulated in cell lines compared to tumor cells and normal cells of the same tissue type included ATP synthesis, cell communication, cell cycle, oxidative phosphorylation, purine, pyrimidine and pyruvate metabolism, and proteasome. Results on metabolic pathways suggested an increase in the velocity nucleotide metabolism and RNA production. Pathways that were downregulated in cell lines compared to tumor and normal tissue included cell communication, cell adhesion molecules (CAMs, and ECM-receptor interaction. Only a fraction of the significantly altered genes in tumor-to-normal comparison had similar expressions in cancer cell lines and tumor cells. These genes were tissue-specific and were distributed sparsely among multiple pathways. Conclusion Significantly altered genes in tumors compared to normal tissue were largely tissue specific. Among these genes downregulation was a major trend. In contrast, cell lines contained large sets of significantly upregulated genes that were common to multiple tissue types. Pathway upregulation in cell lines was most pronounced over metabolic pathways including cell nucleotide metabolism and oxidative

  12. Cell size checkpoint control by the retinoblastoma tumor suppressor pathway.

    Directory of Open Access Journals (Sweden)

    Su-Chiung Fang

    2006-10-01

    Full Text Available Size control is essential for all proliferating cells, and is thought to be regulated by checkpoints that couple cell size to cell cycle progression. The aberrant cell-size phenotypes caused by mutations in the retinoblastoma (RB tumor suppressor pathway are consistent with a role in size checkpoint control, but indirect effects on size caused by altered cell cycle kinetics are difficult to rule out. The multiple fission cell cycle of the unicellular alga Chlamydomonas reinhardtii uncouples growth from division, allowing direct assessment of the relationship between size phenotypes and checkpoint function. Mutations in the C. reinhardtii RB homolog encoded by MAT3 cause supernumerous cell divisions and small cells, suggesting a role for MAT3 in size control. We identified suppressors of an mat3 null allele that had recessive mutations in DP1 or dominant mutations in E2F1, loci encoding homologs of a heterodimeric transcription factor that is targeted by RB-related proteins. Significantly, we determined that the dp1 and e2f1 phenotypes were caused by defects in size checkpoint control and were not due to a lengthened cell cycle. Despite their cell division defects, mat3, dp1, and e2f1 mutants showed almost no changes in periodic transcription of genes induced during S phase and mitosis, many of which are conserved targets of the RB pathway. Conversely, we found that regulation of cell size was unaffected when S phase and mitotic transcription were inhibited. Our data provide direct evidence that the RB pathway mediates cell size checkpoint control and suggest that such control is not directly coupled to the magnitude of periodic cell cycle transcription.

  13. Persea declinata (Bl. Kosterm Bark Crude Extract Induces Apoptosis in MCF-7 Cells via G0/G1 Cell Cycle Arrest, Bcl-2/Bax/Bcl-xl Signaling Pathways, and ROS Generation

    Directory of Open Access Journals (Sweden)

    Putri Narrima

    2014-01-01

    Full Text Available Persea declinata (Bl. Kosterm is a member of the Lauraceae family, widely distributed in Southeast Asia. It is from the same genus with avocado (Persea americana Mill, which is widely consumed as food and for medicinal purposes. In the present study, we examined the anticancer properties of Persea declinata (Bl. Kosterm bark methanolic crude extract (PDM. PDM exhibited a potent antiproliferative effect in MCF-7 human breast cancer cells, with an IC50 value of 16.68 µg/mL after 48 h of treatment. We observed that PDM caused cell cycle arrest and subsequent apoptosis in MCF-7 cells, as exhibited by increased population at G0/G1 phase, higher lactate dehydrogenase (LDH release, and DNA fragmentation. Mechanistic studies showed that PDM caused significant elevation in ROS production, leading to perturbation of mitochondrial membrane potential, cell permeability, and activation of caspases-3/7. On the other hand, real-time PCR and Western blot analysis showed that PDM treatment increased the expression of the proapoptotic molecule, Bax, but decreased the expression of prosurvival proteins, Bcl-2 and Bcl-xL, in a dose-dependent manner. These findings imply that PDM could inhibit proliferation in MCF-7 cells via cell cycle arrest and apoptosis induction, indicating its potential as a therapeutic agent worthy of further development.

  14. Persea declinata (Bl.) Kosterm Bark Crude Extract Induces Apoptosis in MCF-7 Cells via G0/G1 Cell Cycle Arrest, Bcl-2/Bax/Bcl-xl Signaling Pathways, and ROS Generation.

    Science.gov (United States)

    Narrima, Putri; Paydar, Mohammadjavad; Looi, Chung Yeng; Wong, Yi Li; Taha, Hairin; Wong, Won Fen; Ali Mohd, Mustafa; Hadi, A Hamid A

    2014-01-01

    Persea declinata (Bl.) Kosterm is a member of the Lauraceae family, widely distributed in Southeast Asia. It is from the same genus with avocado (Persea americana Mill), which is widely consumed as food and for medicinal purposes. In the present study, we examined the anticancer properties of Persea declinata (Bl.) Kosterm bark methanolic crude extract (PDM). PDM exhibited a potent antiproliferative effect in MCF-7 human breast cancer cells, with an IC50 value of 16.68 µg/mL after 48 h of treatment. We observed that PDM caused cell cycle arrest and subsequent apoptosis in MCF-7 cells, as exhibited by increased population at G0/G1 phase, higher lactate dehydrogenase (LDH) release, and DNA fragmentation. Mechanistic studies showed that PDM caused significant elevation in ROS production, leading to perturbation of mitochondrial membrane potential, cell permeability, and activation of caspases-3/7. On the other hand, real-time PCR and Western blot analysis showed that PDM treatment increased the expression of the proapoptotic molecule, Bax, but decreased the expression of prosurvival proteins, Bcl-2 and Bcl-xL, in a dose-dependent manner. These findings imply that PDM could inhibit proliferation in MCF-7 cells via cell cycle arrest and apoptosis induction, indicating its potential as a therapeutic agent worthy of further development. PMID:24808916

  15. 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....

  16. Aspafilioside B induces G2/M cell cycle arrest and apoptosis by up-regulating H-Ras and N-Ras via ERK and p38 MAPK signaling pathways in human hepatoma HepG2 cells.

    Science.gov (United States)

    Liu, Wei; Ning, Rui; Chen, Rui-Ni; Huang, Xue-Feng; Dai, Qin-Sheng; Hu, Jin-Hua; Wang, Yu-Wen; Wu, Li-Li; Xiong, Jing; Hu, Gang; Guo, Qing-Long; Yang, Jian; Wang, Hao

    2016-05-01

    We recently establish that aspafilioside B, a steroidal saponin extracted from Asparagus filicinus, is an active cytotoxic component. However, its antitumor activity is till unknown. In this study, the anticancer effect of aspafilioside B against HCC cells and the underlying mechanisms were investigated. Our results showed that aspafilioside B inhibited the growth and proliferation of HCC cell lines. Further study revealed that aspafilioside B could significantly induce G2 phase cell cycle arrest and apoptosis, accompanying the accumulation of reactive oxygen species (ROS), but blocking ROS generation with N-acetyl-l-cysteine (NAC) could not prevent G2/M arrest and apoptosis. Additionally, treatment with aspafilioside B induced phosphorylation of extracellular signal-regulated kinase (ERK) and p38 MAP kinase. Moreover, both ERK inhibitor PD98059 and p38 inhibitor SB203580 almost abolished the G2/M phase arrest and apoptosis induced by aspafilioside B, and reversed the expression of cell cycle- and apoptosis-related proteins. We also found that aspafilioside B treatment increased both Ras and Raf activation, and transfection of cells with H-Ras and N-Ras shRNA almost attenuated aspafilioside B-induced G2 phase arrest and apoptosis as well as the ERK and p38 activation. Finally, in vivo, aspafilioside B suppressed tumor growth in mouse xenograft models, and the mechanism was the same as in vitro study. Collectively, these findings indicated that aspafilioside B may up-regulate H-Ras and N-Ras, causing c-Raf phosphorylation, and lead to ERK and p38 activation, which consequently induced the G2 phase arrest and apoptosis. This study provides the evidence that aspafilioside B is a promising therapeutic agent against HCC. PMID:25683703

  17. 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

  18. 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)

  19. Comparative life cycle assessment of three biohydrogen pathways.

    Science.gov (United States)

    Djomo, Sylvestre Njakou; Blumberga, Dagnija

    2011-02-01

    A life cycle assessment was performed to quantify and compare the energetic and environmental performances of hydrogen from wheat straw (WS-H(2)), sweet sorghum stalk (SSS-H(2)), and steam potato peels (SPP-H(2)). Inventory data were derived from a pilot plant. Impacts were assessed using the impact 2002+ method. When co-product was not considered, the greenhouse gas (GHG) emissions were 5.60 kg CO(2eq) kg(-1) H(2) for WS-H(2), 5.32 kg CO(2eq) kg(-1) H(2) for SSS-H(2), and 5.18 kg CO(2eq) kg(-1) H(2) for SPP-H(2). BioH(2) pathways reduced GHG emissions by 52-56% compared to diesel and by 54-57% compared to steam methane reforming production of H(2). The energy ratios (ER) were also comparable: 1.08 for WS-H(2), 1.14 for SSS-H(2) and 1.17 for SPP-H(2). A shift from SPP-H(2) to WS-H(2) would therefore not affect the ER and GHG emissions of these BioH(2) pathways. When co-product was considered, a shift from SPP-H(2) to WS-H(2) or SSS-H(2) decreased the ER, while increasing the GHG emissions significantly. Co-product yield should be considered when selecting BioH(2) feedstocks. PMID:21112211

  20. 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...

  1. The inhibition of activated hepatic stellate cells proliferation by arctigenin through G0/G1 phase cell cycle arrest: persistent p27(Kip1) induction by interfering with PI3K/Akt/FOXO3a signaling pathway.

    Science.gov (United States)

    Li, Ao; Wang, Jun; Wu, Mingjun; Zhang, Xiaoxun; Zhang, Hongzhi

    2015-01-15

    Proliferation of hepatic stellate cells (HSCs) is vital for the development of fibrosis during liver injury. In this study, we describe that arctigenin (ATG), a major bioactive component of Fructus Arctii, exhibited selective cytotoxic activity via inhibiting platelet-derived growth factor-BB (PDGF-BB)-activated HSCs proliferation and arrested cell cycle at G0/G1 phase, which could not be observed in normal human hepatocytes in vitro. The cyclin-dependent kinase (CDK) 4/6 activities could be strongly inhibited by ATG through down-regulation of cyclin D1 and CDK4/6 expression in early G1 phase arrest. In the ATG-treated HSCs, the expression level of p27(Kip1) and the formation of CDK2-p27(Kip1) complex were also increased. p27(Kip1) silencing significantly attenuated the effect of ATG, including cell cycle arrest and suppression of proliferation in activated HSCs. We also found that ATG suppressed PDGF-BB-induced phosphorylation of Akt and its downstream transcription factor Forkhead box O 3a (FOXO3a), decreased binding of FOXO3a to 14-3-3 protein, and stimulated nuclear translocation of FOXO3a in activated HSCs. Furthermore, knockdown of FOXO3a expression by FOXO3a siRNA attenuated ATG-induced up-regulation of p27(Kip1) in activated HSCs. All the above findings suggested that ATG could increase the levels of p27(Kip1) protein through inhibition of Akt and improvement of FOXO3a activity, in turn inhibited the CDK2 kinase activity, and eventually caused an overall inhibition of HSCs proliferation. PMID:25498792

  2. 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

  3. Metastasis and stem cell pathways

    OpenAIRE

    Barnhart, Bryan C.; Simon, M. Celeste

    2007-01-01

    Recent studies have described a small population of self-renewing and multipotent cells within tumors termed “cancer stem cells.” These cells share many traits with somatic and embryonic stem cells and are thought to be responsible for driving tumor progression in a growing list of neoplastic diseases. Cells within solid tumors encounter hypoxia due to poor vascular function. Both long-standing and emerging data describe hypoxic effects on somatic and embryonic stem cells, and it is likely th...

  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 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.

  6. 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...

  7. 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...

  8. RBP-J-interacting and tubulin-associated protein induces apoptosis and cell cycle arrest in human hepatocellular carcinoma by activating the p53–Fbxw7 pathway

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Haihe [The Key Laboratory of Molecular Diagnosis in Laboratory Medicine, Department of Pathogenobiology, Daqing Branch of Harbin Medical University, Daqing 163319 (China); Yang, Zhanchun [Department of General Surgery of Fifth Clinical Hospital of Harbin Medical University, Daqing 163319 (China); Liu, Chunbo; Huang, Shishun; Wang, Hongzhi; Chen, Yingli [The Key Laboratory of Molecular Diagnosis in Laboratory Medicine, Department of Pathogenobiology, Daqing Branch of Harbin Medical University, Daqing 163319 (China); Chen, Guofu, E-mail: zhangyanjie3@aliyun.com [Department of General Surgery of Fifth Clinical Hospital of Harbin Medical University, Daqing 163319 (China)

    2014-11-07

    Highlights: • RITA overexpression increased protein expression of p53 and Fbxw7 and downregulated the expression of cyclin D1, cyclin E, CDK2, Hes-1 and NF-κB p65. • RITA can significantly inhibit the in vitro growth of SMMC7721 and HepG2 cells. • RITA exerts tumor-suppressive effects in hepatocarcinogenesis through induction of G0/G1 cell cycle arrest and apoptosis and suggest a therapeutic application of RITA in HCC. - Abstract: Aberrant Notch signaling is observed in human hepatocellular carcinoma (HCC) and has been associated with the modulation of cell growth. However, the role of Notch signaling in HCC and its underlying mechanism remain elusive. RBP-J-interacting and tubulin-associated (RITA) mediates the nuclear export of RBP-J to tubulin fibers and downregulates Notch-mediated transcription. In this study, we found that RITA overexpression increased protein expression of p53 and Fbxw7 and downregulated the expression of cyclin D1, cyclin E, CDK2, Hes-1 and NF-κB p65. These changes led to growth inhibition and induced G0/G1 cell cycle arrest and apoptosis in SMMC7721 and HepG2 cells. Our findings indicate that RITA exerts tumor-suppressive effects in hepatocarcinogenesis through induction of G0/G1 cell cycle arrest and apoptosis and suggest a therapeutic application of RITA in HCC.

  9. 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

  10. The Kynurenine Pathway in Stem Cell Biology

    OpenAIRE

    Jones, Simon P; Guillemin, Gilles J; Bruce J Brew

    2013-01-01

    The kynurenine pathway (KP) is the main catabolic pathway of the essential amino acid tryptophan. The KP has been identified to play a critical role in regulating immune responses in a variety of experimental settings. It is also known to be involved in several neuroinflammatory diseases including Huntington’s disease, amyotrophic lateral sclerosis, and Alzheimer’s disease. This review considers the current understanding of the role of the KP in stem cell biology. Both of these fundamental ar...

  11. MAPK signal pathways in the regulation of cell proliferation in mammalian cells

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    MAPK families play an important role in complex cellular programs like proliferation, differentiation,development, transformation, and apoptosis. At least three MAPK families have been characterized: extracellular signal-regulated kinase (ERK), Jun kinase (JNK/SAPK) and p38 MAPK. The above effects are fulfilled by regulation of cell cycle engine and other cell proliferation related proteins. In this paper we discussed their functions and cooperation with other signal pathways in regulation of cell proliferation.

  12. 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)

  13. Sorting through the many total-energy-cycle pathways possible with early plug-in hybrids

    International Nuclear Information System (INIS)

    Using the 'total energy cycle' methodology, we compare U.S. near term (to ∼2015) alternative pathways for converting energy to light-duty vehicle kilometers of travel (VKT) in plug-in hybrids (PHEVs), hybrids (HEVs), and conventional vehicles (CVs). For PHEVs, we present total energy-per-unit-of-VKT information two ways (1) energy from the grid during charge depletion (CD); (2) energy from stored on-board fossil fuel when charge sustaining (CS). We examine 'incremental sources of supply of liquid fuel such as (a) oil sands from Canada, (b) Fischer-Tropsch diesel via natural gas imported by LNG tanker, and (c) ethanol from cellulosic biomass. We compare such fuel pathways to various possible power converters producing electricity, including (i) new coal boilers, (ii) new integrated, gasified coal combined cycle (IGCC), (iii) existing natural gas fueled combined cycle (NGCC), (iv) existing natural gas combustion turbines, (v) wood-to-electricity, and (vi) wind/solar. We simulate a fuel cell HEV and also consider the possibility of a plug-in hybrid fuel cell vehicle (FCV). For the simulated FCV our results address the merits of converting some fuels to hydrogen to power the fuel cell vs. conversion of those same fuels to electricity to charge the PHEV battery. The investigation is confined to a U.S. compact sized car (i.e. a world passenger car). Where most other studies have focused on emissions (greenhouse gases and conventional air pollutants), this study focuses on identification of the pathway providing the most vehicle kilometers from each of five feedstocks examined. The GREET 1.7 fuel cycle model and the new GREET 2.7 vehicle cycle model were used as the foundation for this study. Total energy, energy by fuel type, total greenhouse gases (GHGs), volatile organic compounds (VOC), carbon monoxide (CO), nitrogen oxides (NOx), fine particulate (PM2.5) and sulfur oxides (SOx) values are presented. We also isolate the PHEV emissions contribution from varying k

  14. 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.

  15. 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.

  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. 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.

  19. Influence of cell cycle on responses of MCF-7 cells to benzo[a]pyrene

    Directory of Open Access Journals (Sweden)

    Giddings Ian

    2011-06-01

    Full Text Available Abstract Background Benzo[a]pyrene (BaP is a widespread environmental genotoxic carcinogen that damages DNA by forming adducts. This damage along with activation of the aryl hydrocarbon receptor (AHR induces complex transcriptional responses in cells. To investigate whether human cells are more susceptible to BaP in a particular phase of the cell cycle, synchronised breast carcinoma MCF-7 cells were exposed to BaP. Cell cycle progression was analysed by flow cytometry, DNA adduct formation was assessed by 32P-postlabeling analysis, microarrays of 44K human genome-wide oligos and RT-PCR were used to detect gene expression (mRNA changes and Western blotting was performed to determine the expression of some proteins, including cytochrome P450 (CYP 1A1 and CYP1B1, which are involved in BaP metabolism. Results Following BaP exposure, cells evaded G1 arrest and accumulated in S-phase. Higher levels of DNA damage occurred in S- and G2/M- compared with G0/G1-enriched cultures. Genes that were found to have altered expression included those involved in xenobiotic metabolism, apoptosis, cell cycle regulation and DNA repair. Gene ontology and pathway analysis showed the involvement of various signalling pathways in response to BaP exposure, such as the Catenin/Wnt pathway in G1, the ERK pathway in G1 and S, the Nrf2 pathway in S and G2/M and the Akt pathway in G2/M. An important finding was that higher levels of DNA damage in S- and G2/M-enriched cultures correlated with higher levels of CYP1A1 and CYP1B1 mRNA and proteins. Moreover, exposure of synchronised MCF-7 cells to BaP-7,8-diol-9,10-epoxide (BPDE, the ultimate carcinogenic metabolite of BaP, did not result in significant changes in DNA adduct levels at different phases of the cell cycle. Conclusions This study characterised the complex gene response to BaP in MCF-7 cells and revealed a strong correlation between the varying efficiency of BaP metabolism and DNA damage in different phases of the cell

  20. Re-thinking cell cycle regulators : the cross-talk with metabolism.

    Directory of Open Access Journals (Sweden)

    Lluis eFajas

    2013-01-01

    Full Text Available Analyses of genetically engineered mice deficient for cell cycle regulators, including E2F1, cdk4, or, pRB showed that the major phenotypes are metabolic perturbations. These key cell cycle regulators contribute to lipid synthesis, glucose production, insulin secretion, and glycolytic metabolism and it has been shown how deregulation of those pathways can lead to metabolic perturbations and related metabolic diseases, such as obesity and type II diabetes. The cyclin-cdk-Rb-E2F1 pathway regulates adipogenesis in addition to its well-described roles in cell cycle regulation and cancer. It was also proved that E2F1 directly participates in the regulation of pancreatic growth and function. Similarly, cyclin D3, cdk4, and cdk9 are also adipogenic factors with strong effects on whole organism metabolism. These examples illustrate the growing notion that cell cycle regulatory proteins can also modulate metabolic processes. Cell cycle regulators are activated by insulin and glucose, even in non-proliferating cells. Most importantly cell cycle regulators trigger the adaptive metabolic switch that normal and cancer cells require in order to proliferate. These changes include increased lipid synthesis, decreased oxidative, and increased glycolytic metabolism. In summary, cell cycle regulators are essential in the control of anabolic, biosynthetic processes, and block at the same time oxidative and catabolic pathways, which are the metabolic hallmarks of cancer.

  1. Wnt signalling pathway parameters for mammalian cells.

    Science.gov (United States)

    Tan, Chin Wee; Gardiner, Bruce S; Hirokawa, Yumiko; Layton, Meredith J; Smith, David W; Burgess, Antony W

    2012-01-01

    Wnt/β-catenin signalling regulates cell fate, survival, proliferation and differentiation at many stages of mammalian development and pathology. Mutations of two key proteins in the pathway, APC and β-catenin, have been implicated in a range of cancers, including colorectal cancer. Activation of Wnt signalling has been associated with the stabilization and nuclear accumulation of β-catenin and consequential up-regulation of β-catenin/TCF gene transcription. In 2003, Lee et al. constructed a computational model of Wnt signalling supported by experimental data from analysis of time-dependent concentration of Wnt signalling proteins in Xenopus egg extracts. Subsequent studies have used the Xenopus quantitative data to infer Wnt pathway dynamics in other systems. As a basis for understanding Wnt signalling in mammalian cells, a confocal live cell imaging measurement technique is developed to measure the cell and nuclear volumes of MDCK, HEK293T cells and 3 human colorectal cancer cell lines and the concentrations of Wnt signalling proteins β-catenin, Axin, APC, GSK3β and E-cadherin. These parameters provide the basis for formulating Wnt signalling models for kidney/intestinal epithelial mammalian cells. There are significant differences in concentrations of key proteins between Xenopus extracts and mammalian whole cell lysates. Higher concentrations of Axin and lower concentrations of APC are present in mammalian cells. Axin concentrations are greater than APC in kidney epithelial cells, whereas in intestinal epithelial cells the APC concentration is higher than Axin. Computational simulations based on Lee's model, with this new data, suggest a need for a recalibration of the model.A quantitative understanding of Wnt signalling in mammalian cells, in particular human colorectal cancers requires a detailed understanding of the concentrations of key protein complexes over time. Simulations of Wnt signalling in mammalian cells can be initiated with the parameters

  2. Wnt signalling pathway parameters for mammalian cells.

    Directory of Open Access Journals (Sweden)

    Chin Wee Tan

    Full Text Available Wnt/β-catenin signalling regulates cell fate, survival, proliferation and differentiation at many stages of mammalian development and pathology. Mutations of two key proteins in the pathway, APC and β-catenin, have been implicated in a range of cancers, including colorectal cancer. Activation of Wnt signalling has been associated with the stabilization and nuclear accumulation of β-catenin and consequential up-regulation of β-catenin/TCF gene transcription. In 2003, Lee et al. constructed a computational model of Wnt signalling supported by experimental data from analysis of time-dependent concentration of Wnt signalling proteins in Xenopus egg extracts. Subsequent studies have used the Xenopus quantitative data to infer Wnt pathway dynamics in other systems. As a basis for understanding Wnt signalling in mammalian cells, a confocal live cell imaging measurement technique is developed to measure the cell and nuclear volumes of MDCK, HEK293T cells and 3 human colorectal cancer cell lines and the concentrations of Wnt signalling proteins β-catenin, Axin, APC, GSK3β and E-cadherin. These parameters provide the basis for formulating Wnt signalling models for kidney/intestinal epithelial mammalian cells. There are significant differences in concentrations of key proteins between Xenopus extracts and mammalian whole cell lysates. Higher concentrations of Axin and lower concentrations of APC are present in mammalian cells. Axin concentrations are greater than APC in kidney epithelial cells, whereas in intestinal epithelial cells the APC concentration is higher than Axin. Computational simulations based on Lee's model, with this new data, suggest a need for a recalibration of the model.A quantitative understanding of Wnt signalling in mammalian cells, in particular human colorectal cancers requires a detailed understanding of the concentrations of key protein complexes over time. Simulations of Wnt signalling in mammalian cells can be initiated

  3. Berberine induces cell cycle arrest and apoptosis in human gastric carcinoma SNU-5 cell line

    Institute of Scientific and Technical Information of China (English)

    Jing-Pin Lin; Jai-Sing Yang; Jau-Hong Lee; Wen-Tsong Hsieh; Jing-Gung Chung

    2006-01-01

    AIM: To investigate the relationship between the inhibited growth (cytotoxic activity) of berberine and apoptotic pathway with its molecular mechanism of action.METHODS: The in vitro cytotoxic techniques were complemented by cell cycle analysis and determination of sub-G1 for apoptosis in human gastric carcinoma SNU-5 cells. Percentage of viable cells, cell cycle, and sub-G1 group (apoptosis) were examined and determined by the flow cytometric methods. The associated proteins for cell cycle arrest and apoptosis were examined by Western blotting.RESULTS: For SNU-5 cell line, the IC (50) was found to be 48 μmol/L of berberine. In SNU-5 cells treated with 25-200 μmol/L berberine, G2/M cell cycle arrest was observed which was associated with a marked increment of the expression of p53, Wee1 and CDk1 proteins and decreased cyclin B. A concentration-dependent decrease of cells in G0/G1 phase and an increase in G2/M phase were detected. In addition, apoptosis detected as sub-G0 cell population in cell cycle measurement was proved in 25-200 μmol/L berberine-treated cells by monitoring the apoptotic pathway. Apoptosis was identified by sub-G0 cell population, and upregulation of Bax, downregulation of Bcl-2, release of Ca2+, decreased the mitochondrial membrane potential and then led to the release of mitochondrial cytochrome C into the cytoplasm and caused the activation of caspase-3, and finally led to the occurrence of apoptosis.CONCLUSION: Berberine induces p53 expression and leads to the decrease of the mitochondrial membrane potential, Cytochrome C release and activation of caspase-3 for the induction of apoptosis.

  4. 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

  5. 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.

  6. Wnt Signalling Pathway Parameters for Mammalian Cells

    OpenAIRE

    Tan, Chin Wee; Gardiner, Bruce S.; Hirokawa, Yumiko; Layton, Meredith J.; Smith, David W.; Burgess, Antony W.

    2012-01-01

    Wnt/β-catenin signalling regulates cell fate, survival, proliferation and differentiation at many stages of mammalian development and pathology. Mutations of two key proteins in the pathway, APC and β-catenin, have been implicated in a range of cancers, including colorectal cancer. Activation of Wnt signalling has been associated with the stabilization and nuclear accumulation of β-catenin and consequential up-regulation of β-catenin/TCF gene transcription. In 2003, Lee et al. constructed a c...

  7. 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

  8. 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...

  9. 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.

  10. LPA Induces Colon Cancer Cell Proliferation through a Cooperation between the ROCK and STAT-3 Pathways.

    Directory of Open Access Journals (Sweden)

    Fernanda Leve

    Full Text Available Lysophosphatidic acid (LPA plays a critical role in the proliferation and migration of colon cancer cells; however, the downstream signaling events underlying these processes remain poorly characterized. The aim of this study was to investigate the signaling pathways triggered by LPA to regulate the mechanisms involved in the progression of colorectal cancer (CRC. We have used three cell line models of CRC, and initially analyzed the expression profile of LPA receptors (LPAR. Then, we treated the cells with LPA and events related to their tumorigenic potential, such as migration, invasion, anchorage-independent growth, proliferation as well as apoptosis and cell cycle were evaluated. We used the Chip array technique to analyze the global gene expression profiling that occurs after LPA treatment, and we identified cell signaling pathways related to the cell cycle. The inhibition of these pathways verified the conclusions of the transcriptomic analysis. We found that the cell lines expressed LPAR1, -2 and -3 in a differential manner and that 10 μM LPA did not affect cell migration, invasion and anchorage-independent growth, but it did induce proliferation and cell cycle progression in HCT-116 cells. Although LPA in this concentration did not induce transcriptional activity of β-catenin, it promoted the activation of Rho and STAT-3. Moreover, ROCK and STAT-3 inhibitors prevented LPA-induced proliferation, but ROCK inhibition did not prevent STAT-3 activation. Finally, we observed that LPA regulates the expression of genes related to the cell cycle and that the combined inhibition of ROCK and STAT-3 prevented cell cycle progression and increased the LPA-induced expression of cyclins E1, A2 and B1 to a greater degree than either inhibitor alone. Overall, these results demonstrate that LPA increases the proliferative potential of colon adenocarcinoma HCT-116 cells through a mechanism involving cooperation between the Rho-ROCK and STAT3 pathways

  11. Dependency of climate change and carbon cycle on CO2 emission pathways

    International Nuclear Information System (INIS)

    Previous research has indicated that the response of globally average temperature is approximately proportional to cumulative CO2 emissions, yet evidence of the robustness of this relationship over a range of CO2 emission pathways is lacking. To address this, we evaluate the dependency of climate and carbon cycle change on CO2 emission pathways using a fully coupled climate–carbon cycle model. We design five idealized pathways (including an overshoot scenario for cumulative emissions), each of which levels off to final cumulative emissions of 2000 GtC. The cumulative emissions of the overshoot scenario reach 4000 GtC temporarily, subsequently reducing to 2000 GtC as a result of continuous negative emissions. Although we find that responses of climatic variables and the carbon cycle are largely independent of emission pathways, a much weakened Atlantic meridional overturning circulation (AMOC) is projected in the overshoot scenario despite cessation of emissions. This weakened AMOC is enhanced by rapid warming in the Arctic region due to considerable temporary elevation of atmospheric CO2 concentration and induces the decline of surface air temperature and decrease of precipitation over the northern Atlantic and Europe region. Moreover, the weakened AMOC reduces CO2 uptake by the Atlantic and Arctic oceans. However, the weakened AMOC contributes little to the global carbon cycle. In conclusion, although climate variations have been found to be dependent on emission pathways, the global carbon cycle is relatively independent of these emission pathways, at least superficially. (letter)

  12. 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.

  13. TNF-alpha impairs the S-G2/M cell cycle checkpoint and cyclobutane pyrimidine dimer repair in premalignant skin cells: Role of the PI3K-Akt pathway

    DEFF Research Database (Denmark)

    Faurschou, A.; Gniadecki, R.; Calay, D.;

    2008-01-01

    Tumor necrosis factor-alpha (TNF-alpha) is induced by UVB radiation and has been implicated in the early stages of skin carcinogenesis. Here, we show that in normal keratinocytes and the transformed keratinocyte cell lines, HaCaT and A431, TNF-alpha stimulates protein kinase B/Akt, which results ...

  14. Sox17 regulates the Wnt/beta-catenin signaling pathway in oligodendrocyte progenitor cells

    OpenAIRE

    Chew, Li-Jin; Shen, Weiping; Ming, Xiaotian; Senatorov, Vladimir V.; Chen, Hui-Ling; Ying CHENG; Hong, Elim; Knoblach, Susan; Gallo, Vittorio

    2011-01-01

    The SRY-box (Sox) transcription factors regulate oligodendrocyte differentiation, but their signaling targets are largely unknown. We have identified a major signal transduction pathway regulated by Sox17 in the oligodendrocyte lineage. Microarray analysis in oligodendrocyte progenitor cells (OPCs) after Sox17 attenuation revealed upregulated genes associated with cell cycle control and activation of the Wnt/beta-catenin-pathway. Sox17 knockdown also increases the levels of cyclinD1, Axin2 an...

  15. Deoxyelephantopin from Elephantopus scaber L. induces cell-cycle arrest and apoptosis in the human nasopharyngeal cancer CNE cells

    International Nuclear Information System (INIS)

    Highlights: → Deoxyelephantopin (ESD) inhibited cell proliferation in the human nasopharyngeal cancer CNE cells. → ESD induced cell cycle arrest in S and G2/M phases via modulation of cell cycle regulatory proteins. → ESD triggered apoptosis by dysfunction of mitochondria and induction of both intrinsic and extrinsic apoptotic signaling pathways. → ESD also triggered Akt, ERK, and JNK signaling pathways. -- Abstract: Deoxyelephantopin (ESD), a naturally occurring sesquiterpene lactone present in the Chinese medicinal herb, Elephantopus scaber L. exerted anticancer effects on various cultured cancer cells. However, the cellular mechanisms by which it controls the development of the cancer cells are unavailable, particularly the human nasopharyngeal cancer CNE cells. In this study, we found that ESD inhibited the CNE cell proliferation. Cell cycle arrest in S and G2/M phases was also found. Western blotting analysis showed that modulation of cell cycle regulatory proteins was responsible for the ESD-induced cell cycle arrest. Besides, ESD also triggered apoptosis in CNE cells. Dysfunction in mitochondria was found to be associated with the ESD-induced apoptosis as evidenced by the loss of mitochondrial membrane potential (ΔΨm), the translocation of cytochrome c, and the regulation of Bcl-2 family proteins. Despite the Western blotting analysis showed that both intrinsic and extrinsic apoptotic pathways (cleavage of caspases-3, -7, -8, -9, and -10) were triggered in the ESD-induced apoptosis, additional analysis also showed that the induction of apoptosis could be achieved by the caspase-independent manner. Besides, Akt, ERK and JNK pathways were found to involve in ESD-induced cell death. Overall, our findings provided the first evidence that ESD induced cell cycle arrest, and apoptosis in CNE cells. ESD could be a potential chemotherapeutic agent in the treatment of nasopharyngeal cancer (NPC).

  16. 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...

  17. Persea declinata (Bl.) Kosterm Bark Crude Extract Induces Apoptosis in MCF-7 Cells via G0/G1 Cell Cycle Arrest, Bcl-2/Bax/Bcl-xl Signaling Pathways, and ROS Generation

    OpenAIRE

    2014-01-01

    Persea declinata (Bl.) Kosterm is a member of the Lauraceae family, widely distributed in Southeast Asia. It is from the same genus with avocado (Persea americana Mill), which is widely consumed as food and for medicinal purposes. In the present study, we examined the anticancer properties of Persea declinata (Bl.) Kosterm bark methanolic crude extract (PDM). PDM exhibited a potent antiproliferative effect in MCF-7 human breast cancer cells, with an IC50 value of 16.68 µg/mL after 48 h of tre...

  18. Danusertib, a potent pan-Aurora kinase and ABL kinase inhibitor, induces cell cycle arrest and programmed cell death and inhibits epithelial to mesenchymal transition involving the PI3K/Akt/mTOR-mediated signaling pathway in human gastric cancer AGS and NCI-N78 cells

    Directory of Open Access Journals (Sweden)

    Yuan CX

    2015-03-01

    autophagy-inducing effects on AGS and NCI-N78 cells. Danusertib arrested AGS and NCI-N78 cells in G2/M phase, with downregulation of expression of cyclin B1 and cyclin-dependent kinase 1 and upregulation of expression of p21 Waf1/Cip1, p27 Kip1, and p53. Danusertib induced mitochondria-mediated apoptosis, with an increase in expression of proapoptotic protein and a decrease in antiapoptotic proteins in both cell lines. Danusertib induced release of cytochrome c from the mitochondria to the cytosol and triggered activation of caspase 9 and caspase 3 in AGS and NCI-N78 cells. Further, danusertib induced autophagy, with an increase in expression of beclin 1 and conversion of microtubule-associated protein 1A/1B-light chain 3 (LC3-I to LC3-II in both cell lines. Inhibition of phosphatidylinositol 3-kinase (PI3K/protein kinase B (Akt/mammalian target of rapamycin (mTOR and p38 mitogen-activated protein kinase pathways as well as activation of 5' AMP-activated protein kinase contributed to the proautophagic effect of danusertib in AGS and NCI-N78 cells. SB202191 and wortmannin enhanced the autophagy-inducing effect of danusertib in AGS and NCI-N78 cells. In addition, danusertib inhibited epithelial to mesenchymal transition with an increase in expression of E-cadherin and a decrease in expression of N-cadherin in both cell lines. Taken together, danusertib has potent inducing effects on cell cycle arrest, apoptosis, and autophagy, but has an inhibitory effect on epithelial to mesenchymal transition, with involvement of signaling pathways mediated by PI3K/Akt/mTOR, p38 mitogen-activated protein kinase, and 5' AMP-activated protein kinase in AGS and NCI-N78 cells. Keywords: danusertib, gastric cancer, Aurora kinase, apoptosis, autophagy, epithelial to mesenchymal transition

  19. 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 ...

  20. 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...

  1. 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

  2. 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...

  3. 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

  4. 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...

  5. 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

  6. Mechanisms involved in ceramide-induced cell cycle arrest in human hepatocarcinoma cells

    Institute of Scientific and Technical Information of China (English)

    Jing Wang; Xiao-Wen Lv; Jie-Ping Shi; Xiao-Song Hu

    2007-01-01

    AIM:To investigate the effect of ceramide on the cell cycle in human hepatocarcinoma Bel7402 cells.Possible molecular mechanisms were explored.METHODS:[3-(4,5)-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide(MTT)assay,plasmid transfection,reporter assay,FACS and Western blotting analyses were employed to investigate the effect and the related molecular mechanisms of C2-ceramide on the cell cycle of Bel7402 cells.RESULTS:C2-ceramide was found to inhibit the growth of Bel7402 cells by inducing cell cycle arrest.During the process,the expression of p21 protein increased,while that of cyclinD1,phospho-ERK1/2 and c-myc decreased.Furthermore,the level of CDK7 was downregulated,while the transcriptional activity of PPARγ was upregulated.Addition of GW9662,which is a PPARγ specific antagonist,could reserve the modulation action on CDK7.CONCLUSION:Our results support the hypothesis that cell cycle arrest induced by C2-ceramide may be mediated via accumulation of p21 and reduction of cyclinD1 and CDK7,at least partly,through PPARγ activation.The ERK signaling pathway was involved in this process.

  7. 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...

  8. 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...

  9. PP2A as a master regulator of the cell cycle

    Science.gov (United States)

    Wlodarchak, Nathan; Xing, Yongna

    2016-01-01

    Protein phosphatase 2A (PP2A) plays a critical multi-faceted role in the regulation of the cell cycle. It is known to dephosphorylate over 300 substrates involved in the cell cycle, regulating almost all major pathways and cell cycle checkpoints. PP2A is involved in such diverse processes by the formation of structurally distinct families of holoenzymes, which are regulated spatially and temporally by specific regulators. Here, we review the involvement of PP2A in the regulation of three cell signaling pathways: wnt, mTOR and MAP kinase, as well as the G1→S transition, DNA synthesis and mitotic initiation. These processes are all crucial for proper cell survival and proliferation and are often deregulated in cancer and other diseases. PMID:26906453

  10. Simplified life cycle assessment models: methodological framework and applications to energy pathways

    International Nuclear Information System (INIS)

    The energy transition debate is a key issue for today and the coming years. One of the challenges is to limit the environmental impacts of electricity production. Decision support tools, sufficiently accurate, simple to use, accounting for environmental aspects and favoring future energetic choices, must be implemented. However, the environmental assessment of the energy pathways is complex, and it means considering a two levels characterization. The 'energy pathway' is the first level and corresponds to its environmental distribution, to compare overall pathways. The 'system pathway' is the 2. level and compares environmental impacts of systems within each pathway. We have devised a generic methodology covering both necessary characterization levels by estimating the energy pathways environmental profiles while allowing a simple comparison of its systems environmental impacts. This methodology is based on the definition of a parameterized Life Cycle Assessment model and considers, through a Global Sensitivity Analysis, the environmental impacts of a large sample of systems representative of an energy pathway. As a second step, this methodology defines simplified models based on few key parameters identified as inducing the largest variability in the energy pathway environmental impacts. These models assess in a simple way the systems environmental impacts, avoiding any complex LCAs. This reduction methodology has been applied to the onshore wind power energy pathway in Europe and the photovoltaic energy pathway in France. (author)

  11. Putative intermediates in the nerve cell differentiation pathway in hydra have properties of multipotent stem cells

    Energy Technology Data Exchange (ETDEWEB)

    Holstein, T.W.; David, C.N. (Univ. of Munich (Germany, F.R.))

    1990-12-01

    We have investigated the properties of nerve cell precursors in hydra by analyzing the differentiation and proliferation capacity of interstitial cells in the peduncle of Hydra oligactis, which is a region of active nerve cell differentiation. Our results indicate that about 50% of the interstitial cells in the peduncle can grow rapidly and also give rise to nematocyte precursors when transplanted into a gastric environment. If these cells were committed nerve cell precursors, one would not expect them to differentiate into nematocytes nor to proliferate apparently without limit. Therefore we conclude that cycling interstitial cells in peduncles are not intermediates in the nerve cell differentiation pathway but are stem cells. The remaining interstitial cells in the peduncle are in G1 and have the properties of committed nerve cell precursors. Thus, the interstitial cell population in the peduncle contains both stem cells and noncycling nerve precursors. The presence of stem cells in this region makes it likely that these cells are the immediate targets of signals which give rise to nerve cells.

  12. Putative intermediates in the nerve cell differentiation pathway in hydra have properties of multipotent stem cells

    International Nuclear Information System (INIS)

    We have investigated the properties of nerve cell precursors in hydra by analyzing the differentiation and proliferation capacity of interstitial cells in the peduncle of Hydra oligactis, which is a region of active nerve cell differentiation. Our results indicate that about 50% of the interstitial cells in the peduncle can grow rapidly and also give rise to nematocyte precursors when transplanted into a gastric environment. If these cells were committed nerve cell precursors, one would not expect them to differentiate into nematocytes nor to proliferate apparently without limit. Therefore we conclude that cycling interstitial cells in peduncles are not intermediates in the nerve cell differentiation pathway but are stem cells. The remaining interstitial cells in the peduncle are in G1 and have the properties of committed nerve cell precursors. Thus, the interstitial cell population in the peduncle contains both stem cells and noncycling nerve precursors. The presence of stem cells in this region makes it likely that these cells are the immediate targets of signals which give rise to nerve cells

  13. Alisertib Induces Cell Cycle Arrest, Apoptosis, Autophagy and Suppresses EMT in HT29 and Caco-2 Cells

    Directory of Open Access Journals (Sweden)

    Bao-Jun Ren

    2015-12-01

    Full Text Available Colorectal cancer (CRC is one of the most common malignancies worldwide with substantial mortality and morbidity. Alisertib (ALS is a selective Aurora kinase A (AURKA inhibitor with unclear effect and molecular interactome on CRC. This study aimed to evaluate the molecular interactome and anticancer effect of ALS and explore the underlying mechanisms in HT29 and Caco-2 cells. ALS markedly arrested cells in G2/M phase in both cell lines, accompanied by remarkable alterations in the expression level of key cell cycle regulators. ALS induced apoptosis in HT29 and Caco-2 cells through mitochondrial and death receptor pathways. ALS also induced autophagy in HT29 and Caco-2 cells, with the suppression of phosphoinositide 3-kinase (PI3K/protein kinase B (Akt/mammalian target of rapamycin (mTOR, but activation of 5′ AMP-activated protein kinase (AMPK signaling pathways. There was a differential modulating effect of ALS on p38 MAPK signaling pathway in both cell lines. Moreover, induction or inhibition of autophagy modulated basal and ALS-induced apoptosis in both cell lines. ALS potently suppressed epithelial to mesenchymal transition (EMT in HT29 and Caco-2 cells. Collectively, it suggests that induction of cell cycle arrest, promotion of apoptosis and autophagy, and suppression of EMT involving mitochondrial, death receptor, PI3K/Akt/mTOR, p38 MAPK, and AMPK signaling pathways contribute to the cancer cell killing effect of ALS on CRC cells.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2012-11-09

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

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

    International Nuclear Information System (INIS)

    Highlights: ► We investigate mechanisms responsible for butyrate resistance in colon cancer cells. ► Tcf3 modulates butyrate’s effects on Wnt activity and cell growth in resistant cells. ► Tcf3 modulation of butyrate’s effects differ by cell context. ► Cell cycle factors are overexpressed in the resistant cells. ► Reversal of altered gene expression can enhance the anti-cancer effects of butyrate. -- Abstract: Butyrate, a fermentation product of dietary fiber, inhibits clonal growth in colorectal cancer (CRC) cells dependent upon the fold induction of Wnt activity. We have developed a CRC cell line (HCT-R) that, unlike its parental cell line, HCT-116, does not respond to butyrate exposure with hyperactivation of Wnt signaling and suppressed clonal growth. PCR array analyses revealed Wnt pathway-related genes, the expression of which differs between butyrate-sensitive HCT-116 CRC cells and their butyrate-resistant HCT-R cell counterparts. We identified overexpression of Tcf3 as being partially responsible for the butyrate-resistant phenotype, as this DNA-binding protein suppresses the hyperinduction of Wnt activity by butyrate. Consequently, Tcf3 knockdown in HCT-R cells restores their sensitivity to the effects of butyrate on Wnt activity and clonal cell growth. Interestingly, the effects of overexpressed Tcf3 differ between HCT-116 and HCT-R cells; thus, in HCT-116 cells Tcf3 suppresses proliferation without rendering the cells resistant to butyrate. In HCT-R cells, however, the overexpression of Tcf3 inhibits Wnt activity, and the cells are still able to proliferate due to the higher expression levels of cell cycle factors, particularly those driving the G1 to S transition. Knowledge of the molecular mechanisms determining the variable sensitivity of CRC cells to butyrate may assist in developing approaches that prevent or reverse butyrate resistance.

  16. 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.

  17. Alteration of cell cycle progression by Sindbis virus infection

    Energy Technology Data Exchange (ETDEWEB)

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

    2015-07-10

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

  18. Lack of telomerase activity in rabbit bone marrow stromal cells during differentiation along neural pathway

    Institute of Scientific and Technical Information of China (English)

    CHEN Zhen-zhou; XU Ru-xiang; JIANG Xiao-dan; TENG Xiao-hua; LI Gui-tao; ZHOU Yü-xi

    2006-01-01

    Objective: To investigate telomerase activity in rabbit bone marrow stromal cells (BMSCs) during their committed differentiation in vitro along neural pathway and the effect of glial cell line-derived neurotrophic factor (GDNF) on the expression of telomerase.Methods: BMSCs were acquired from rabbit marrow and divided into control group, GDNF (10 ng/ml) group.No. ZL02134314. 4) supplemented with 10% fetal bovine serum (FBS) was used to induce BMSCs differentiation along neural pathway. Fluorescent immunocytochemistry was employed to identify the expressions of Nestin, neuronspecific endase (NSE), and gial fibrillary acidic protein (GFAP). The growth curves of the cells and the status of cell cycles were analyzed, respectively. During the differentiation, telomerase activitys were detected using the telomeric repeat amplification protocol-enzyme-linked immunosorbent assay (TRAP-ELISA).Results: BMSCs were successfully induced to differentiate along neural pathway and expressed specific markers of fetal neural epithelium, mature neuron and glial cells. Telomerase activities were undetectable in BMSCs during differentiation along neural pathway. Similar changes of cell growth curves, cell cycle status and telomerase expression were observed in the two groups.Conclusions: Rabbit BMSCs do not display telomerase activity during differentiation along neural pathway. GDNF shows little impact on proliferation and telomerase activity of BMSCs.

  19. Nutrient availability regulates cell cycle through a Pho85 CDK-dependent control of Cln3 cyclin stability

    OpenAIRE

    Menoyo Molins, Alexandra

    2012-01-01

    Cell cycle control by trophic factors has a key role in regulation of cell proliferation in all organisms. Nutrients are one of these important factors needed by cells to reproduce, so very well regulated mechanisms must exist that connect nutrient availability to cell cycle. Hence the importance on studying how exactly nutrient-dependent signaling pathways work. Cln3, the most upstream G1 cyclin in Saccharomyces cerevisiae, is one well demonstrated common effector of multiple nutrient-dep...

  20. Change of the cell cycle after flutamide treatment in prostate cancer cells and its molecular mechanism

    Institute of Scientific and Technical Information of China (English)

    Yong Wang; Wei-Jun Qin; He Wang; Guo-Xing Shao; Chen Shao; Chang-Hong Shi; Lei Zhang; Hong-Hong Yue; Peng-Fei Wang; Bo Yang; Yun-Tao Zhang; Fan Liu

    2005-01-01

    Aim: To explore the effect of androgen receptor (AR) on the expression of the cell cycle-related genes, such as CDKN1A and BTG1, in prostate cancer cell line LNCaP. Methods: After AR antagonist flutamide treatment and confirmation of its effect by phase contrast microscope and flow cytometry, the differential expression of the cell cycle-related genes was analyzed by a cDNA microarray. The flutamide treated cells were set as the experimental group and the LNCaP cells as the control. We labeled cDNA probes of the experimental group and control group with Cy5 and Cy3 dyes, respectively, through reverse transcription. Then we hybridized the cDNA probes with cDNA microarrays, which contained 8 126 unique human cDNA sequences and the chip was scanned to get the fluorescent values of Cy5 and Cy3 on each spot. After primary analysis, reverse transcription polymerase chain reaction (RTPCR) tests were carried out to confirm the results of the chips. Results:After AR antagonist flutamide treatment,three hundred and twenty-six genes (3.93 %) expressed differentially, 97 down-regulated and 219 up-regulated.Among them, eight up-regulated genes might be cell cycle-related, namely CDC10, NRAS, BTG1, Weel, CLK3,DKFZP564A122, CDKN1A and BTG2. The CDKN1A and BTG1 gene mRNA expression was confirmed to be higher in the experimental group by RT-PCR, whilep53 mRNA expression had no significant changes. Conclusion: Flutamide treatment might up-regulate CDKN1A and BTG1 expression in prostate cancer cells. The protein expressions of CDKN1A and BTG1 play an important role in inhibiting the proliferation of cancer cells. CDKN1A has a great impact on the cell cycle of prostate cancer cells and may play a role in the cancer cells in a p53-independent pathway. The prostate cancer cells might affect the cell cycle-related genes by activating AR and thus break the cell cycle control.

  1. 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)

  2. A cell-free framework for rapid biosynthetic pathway prototyping and enzyme discovery.

    Science.gov (United States)

    Karim, Ashty S; Jewett, Michael C

    2016-07-01

    Speeding up design-build-test (DBT) cycles is a fundamental challenge facing biochemical engineering. To address this challenge, we report a new cell-free protein synthesis driven metabolic engineering (CFPS-ME) framework for rapid biosynthetic pathway prototyping. In our framework, cell-free cocktails for synthesizing target small molecules are assembled in a mix-and-match fashion from crude cell lysates either containing selectively enriched pathway enzymes from heterologous overexpression or directly producing pathway enzymes in lysates by CFPS. As a model, we apply our approach to n-butanol biosynthesis showing that Escherichia coli lysates support a highly active 17-step CoA-dependent n-butanol pathway in vitro. The elevated degree of flexibility in the cell-free environment allows us to manipulate physiochemical conditions, access enzymatic nodes, discover new enzymes, and prototype enzyme sets with linear DNA templates to study pathway performance. We anticipate that CFPS-ME will facilitate efforts to define, manipulate, and understand metabolic pathways for accelerated DBT cycles without the need to reengineer organisms. PMID:26996382

  3. New activators and inhibitors in the hair cycle clock: targeting stem cells' state of competence.

    Science.gov (United States)

    Plikus, Maksim V

    2012-05-01

    The timing mechanism of the hair cycle remains poorly understood. However, it has become increasingly clear that the telogen-to-anagen transition is controlled jointly by at least the bone morphogenic protein (BMP), WNT, fibroblast growth factor (FGF), and transforming growth factor (TGF)-β signaling pathways. New research shows that Fgf18 signaling in hair follicle stem cells synergizes BMP-mediated refractivity, whereas Tgf-β2 signaling counterbalances it. Loss of Fgf18 signaling markedly accelerates anagen initiation, whereas loss of Tgf-β2 signaling significantly delays it, supporting key roles for these pathways in hair cycle timekeeping. PMID:22499035

  4. 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.

  5. 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.

  6. Quantitative Analysis of Energy Metabolic Pathways in MCF-7 Breast Cancer Cells by Selected Reaction Monitoring Assay*

    OpenAIRE

    Drabovich, Andrei P.; Pavlou, Maria P.; Dimitromanolakis, Apostolos; Diamandis, Eleftherios P.

    2012-01-01

    To investigate the quantitative response of energy metabolic pathways in human MCF-7 breast cancer cells to hypoxia, glucose deprivation, and estradiol stimulation, we developed a targeted proteomics assay for accurate quantification of protein expression in glycolysis/gluconeogenesis, TCA cycle, and pentose phosphate pathways. Cell growth conditions were selected to roughly mimic the exposure of cells in the cancer tissue to the intermittent hypoxia, glucose deprivation, and hormonal stimula...

  7. Radiation-induced autophagy promotes esophageal squamous cell carcinoma cell survival via the LKB1 pathway.

    Science.gov (United States)

    Lu, Chi; Xie, Conghua

    2016-06-01

    Radiotherapy is an important treatment modality for esophageal cancer; however, the clinical efficacy of radiotherapy is limited by tumor radioresistance. In the present study, we explored the hypothesis that radiation induces tumor cell autophagy as a cytoprotective adaptive response, which depends on liver kinase B1 (LKB1) also known as serine/threonine kinase 11 (STK11). Radiation-induced Eca-109 cell autophagy was found to be dependent on signaling through the LKB1 pathway, and autophagy inhibitors that disrupted radiation-induced Eca-109 cell autophagy increased cell cycle arrest and cell death in vitro. Inhibition of autophagy also reduced the clonogenic survival of the Eca-109 cells. When treated with radiation alone, human esophageal carcinoma xenografts showed increased LC3B and p-LKB1 expression, which was decreased by the autophagy inhibitor chloroquine. In vivo inhibition of autophagy disrupted tumor growth and increased tumor apoptosis when combined with 6 Gy of ionizing radiation. In summary, our findings elucidate a novel mechanism of resistance to radiotherapy in which radiation-induced autophagy, via the LKB1 pathway, promotes tumor cell survival. This indicates that inhibition of autophagy can serve as an adjuvant treatment to improve the curative effect of radiotherapy. PMID:27109915

  8. 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.)

  9. Apoptosis Cell Death Effect of Scrophularia Variegata on Breast Cancer Cells via Mitochondrial Intrinsic Pathway

    Science.gov (United States)

    Azadmehr, Abbas; Hajiaghaee, Reza; Baradaran, Behzad; Haghdoost-Yazdi, Hashem

    2015-01-01

    Purpose: Scrophularia variegata M. Beib. (Scrophulariaceae) is an Iranian medicinal plant which is used for various inflammatory disorders in traditional medicine. In this study we evaluated the anti-cancer and cytotoxic effects of the Scrophularia variegata (S. variegata) ethanolic extract on the human breast cancer cell line. Methods: The cytotoxicity effect of the extract on MCF-7 cells was evaluated by MTT assay. In addition, Caspase activity, DNA ladder and Cell death were evaluated by ELISA, gel electrophoresis and Annexin V-FITC/PI staining, respectively. Results: The S. variegata extract showed significant effect cytotoxicity on MCF-7 human breast cancer cell line. Treatment with the extract induced apoptosis on the breast cancer cells by cell cycle arrest in G2/M phase. The results indicated that cytotoxicity activity was associated with an increase of apoptosis as demonstrated by DNA fragmentation as well as an increase of the amount of caspase 3 and caspase 9. In addition, the phytochemical assay showed that the extract had antioxidant capacity and also flavonoids, phenolic compounds and phenyl propanoids were presented in the extract. Conclusion: Our findings indicated that S. variegata extract induced apoptosis via mitochondrial intrinsic pathway on breast cancer by cell cycle arrest in G2/M phase and an increase of caspase 3 and caspase 9. However future studies are needed. PMID:26504768

  10. Well-to-wheels analysis of hydrogen based fuel-cell vehicle pathways in Shanghai

    International Nuclear Information System (INIS)

    Due to high energy efficiency and zero emissions, some believe fuel cell vehicles (FCVs) could revolutionize the automobile industry by replacing internal combustion engine technology, and first boom in China. However, hydrogen infrastructure is one of the major barriers. Because different H2 pathways have very different energy and emissions effects, the well-to-wheels (WTW) analyses are necessary for adequately evaluating fuel/vehicle systems. The pathways used to supply H2 for FCVs must be carefully examined by their WTW energy use, greenhouse gases (GHGs) emissions, total criteria pollutions emissions, and urban criteria pollutions emissions. Ten hydrogen pathways in Shanghai have been simulated. The results include well-to-wheels energy use, GHGs emissions, total criteria pollutions and urban criteria pollutions. A fuel-cycle model developed at Argonne National Laboratory-called the Greenhouse gases, Regulated Emissions, and Energy use in Transportation (GREET) model-was used to evaluate well-to-wheels energy and emissions impacts of hydrogen pathways in this study. Because the initial GREET model had no coal and naphtha-based hydrogen pathways, four hydrogen pathway computer programs were added to GREET in the research. To analyze uncertain impacts, commercial software, Crystal Ball(TM) was used to conduct Monte Carlo simulations. Hence, instead of point estimates, the results of this study were probability distributions. Through the research of H2 pathways in Shanghai, the following conclusions were achieved:(1)All the pathways have significant reductions in WTW petroleum use, except two H2 pathways from naphtha, which achieve about 20% reductions in WTW petroleum. (2)All the pathways have significant reductions in WTW urban criteria pollutions emissions, except two H2 pathways from coal, which result in significant increases in WTW urban SOX emissions. (3)The NG-based H2 pathways have the best WTW energy efficiencies, and the electrolysis H2 pathways have

  11. 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

  12. ATR pathway inhibition is synthetically lethal in cancer cells with ERCC1 deficiency

    OpenAIRE

    Mohni, Kareem N.; Kavanaugh, Gina M.; Cortez, David

    2014-01-01

    The DNA damage response kinase ATR and its effector kinase CHEK1 are required for cancer cells to survive oncogene-induced replication stress. ATR inhibitors exhibit synthetic lethal interactions with deficiencies in the DNA damage response enzymes ATM and XRCC1 and with overexpression of the cell cycle kinase Cyclin E. Here we report a systematic screen to identify synthetic lethal interactions with ATR-pathway targeted drugs, rationalized by their predicted therapeutic utility in the oncolo...

  13. Radioresistance-related signaling pathways in nasopharyngeal carcinoma cells

    International Nuclear Information System (INIS)

    Objective: To study the difference of gene expression profile between the radioresistant human nasopharyngeal carcinoma cell line CNE-2R and CNE-2, and to screen the signaling pathway associated with radioresistance of nasopharyngeal carcinoma. Methods: The radioresistant nasopharyngeal carcinoma cell line CNE-2R was constructed from the original cell line CNE-2. CNE-2R and CNE-2 cells were cultured and administered with 60Co γ-ray irradiation at the dose of 400 cGy for 15 times. Human-6v 3.0 whole genome expression profile was used to screen the differentially expressed genes. Bioinformatic analysis was used to identify the pathways related to radioresistance. Results: The number of the differentially expressed genes that were found in these 2 experiments was 374. The Kegg pathway and Biocarta pathway analysis of the differentially expressed genes showed the biological importance of Toll-like receptor signaling pathway and IL-1 R-mediated signal transduction pathway to the radioresistance of the CNE-2R cells and the significant differences of 13 genes in these 2 pathways,including JUN, MYD88, CCL5, CXCL10, STAT1, LY96, FOS, CCL3, IL-6, IL-8, IL-1α, IL-1β, and IRAK2 (t=13.47-66.57, P<0.05). Conclusions: Toll-like receptor signaling pathway and IL-1R-mediated signal transduction pathway might be related to the occurrence of radioresistance. (authors)

  14. Andrographolide Suppresses Proliferation of Nasopharyngeal Carcinoma Cells via Attenuating NF-κB Pathway

    Directory of Open Access Journals (Sweden)

    Tao Peng

    2015-01-01

    Full Text Available Andrographolide (Andro has been reported to have anticancer activity in multiple types of cancer due to its capacity to inactivate NF-κB pathway. Previous studies showed the therapeutic potential of targeting NF-κB pathway in nasopharyngeal carcinoma (NPC. However, the anticancer activity of Andro in NPC has not been reported. In this study, we defined the anticancer effects of Andro in NPC and elucidated its potential mechanisms of action. Our results showed that Andro significantly inhibited the proliferation and invasion of NPC cells (P<0.05, resp.. These anticancer activities were associated with cell apoptosis, cell death and induction of cell cycle arrest, and the downregulation of NF-κB target genes. This work provides evidence that NF-κB pathway is a potential therapeutic target and may also be indispensable in the Andro-mediated anticancer activities in nasopharyngeal carcinoma.

  15. Activation of the cell wall integrity pathway promotes escape from G2 in the fungus Ustilago maydis.

    Directory of Open Access Journals (Sweden)

    Natalia Carbó

    2010-07-01

    Full Text Available It is widely accepted that MAPK activation in budding and fission yeasts is often associated with negative effects on cell cycle progression, resulting in delay or arrest at a specific stage in the cell cycle, thereby enabling cells to adapt to changing environmental conditions. For instance, activation of the Cell Wall Integrity (CWI pathway in the budding yeast Saccharomyces cerevisiae signals an increase in CDK inhibitory phosphorylation, which leads cells to remain in the G2 phase. Here we characterized the CWI pathway of Ustilago maydis, a fungus evolutionarily distant from budding and fission yeasts, and show that activation of the CWI pathway forces cells to escape from G2 phase. In spite of these disparate cell cycle responses in S. cerevisiae and U. maydis, the CWI pathway in both organisms appears to respond to the same class cell wall stressors. To understand the basis of such a difference, we studied the mechanism behind the U. maydis response. We found that activation of CWI pathway in U. maydis results in a decrease in CDK inhibitory phosphorylation, which depends on the mitotic phosphatase Cdc25. Moreover, in response to activation of the CWI pathway, Cdc25 accumulates in the nucleus, providing a likely explanation for the increase in the unphosphorylated form of CDK. We also found that the extended N-terminal domain of Cdc25, which is dispensable under normal growth conditions, is required for this G2 escape as well as for resistance to cell wall stressors. We propose that the process of cell cycle adaptation to cell stress evolved differently in these two divergent organisms so that each can move towards a cell cycle phase most appropriate for responding to the environmental signals encountered.

  16. Susceptible genes and molecular pathways related to heavy ion irradiation in oral squamous cell carcinoma cells

    International Nuclear Information System (INIS)

    Background and purpose: Heavy ion beams are high linear energy transfer (LET) radiation characterized by a higher relative biologic effectiveness than low LET radiation. The aim of the current study was to determine the difference of gene expression between heavy ion beams and X-rays in oral squamous cell carcinoma (OSCC)-derived cells. Materials and methods: The OSCC cells were irradiated with accelerated carbon or neon ion irradiation or X-rays using three different doses. We sought to identify genes the expression of which is affected by carbon and neon ion irradiation using Affymetrix GeneChip analysis. The identified genes were analyzed using the Ingenuity Pathway Analysis Tool to investigate the functional network and gene ontology. Changes in mRNA expression in the genes were assessed by real-time quantitative reverse transcriptase-polymerase chain reaction (qRT-PCR). Results: The microarray analysis identified 84 genes that were modulated by carbon and neon ion irradiation at all doses in OSCC cells. Among the genes, three genes (TGFBR2, SMURF2, and BMP7) and two genes (CCND1 and E2F3), respectively, were found to be involved in the transforming growth factor β-signaling pathway and cell cycle:G1/S checkpoint regulation pathway. The qRT-PCR data from the five genes after heavy ion irradiation were consistent with the microarray data (P < 0.01). Conclusion: Our findings should serve as a basis for global characterization of radiation-regulated genes and pathways in heavy ion-irradiated OSCC

  17. Quantitative proteomic analysis for radiation-induced cell cycle suspension in 92-1 melanoma cell line

    International Nuclear Information System (INIS)

    Melanoma is a malignant tumor with high invasive and metastatic properties. Though radiation is the major therapy for melanoma, its radio-resistance has been shown to severely influence the clinical outcome. So it is imperative to enhance the sensitivity of uveal melanoma cells to radiotherapy. Previously, we found that the cell cycle of 92-1 uveal melanoma cells was suspended and remained unchanged for up to 5 days after exposure to 10 Gy of X-rays, which might be relevant to the high radio-sensitivity of 92-1 cells. To further investigate the cell cycle suspension-associated proteins, we employed two analyses with stable isotope labeling with amino acids in cell culture technology and two-dimensional liquid chromatography tandem mass spectrometry. Cells were incubated for 15 h or 48 h after irradiation with 10 Gy of X-rays. We identified a total of 737 proteins at 15 h (Group A) and 530 proteins at 48 h post-irradiation (Group B). The gene ontology biological pathway was used to obtain a systems level view of proteome changes in 92-1 cells under cell cycle suspension. We further selected the significantly changed proteins for investigation of their potential contribution to cell cycle suspension, growth arrest and cell senescence. These proteins are involved in the cell cycle, stress response, glycolysis and the tricarboxylic acid cycle, etc. Our study expected to reveal potential marker proteins associated with cell suspension induced by irradiation, which might contribute to understanding the mechanism beyond the cell cycle suspension. (author)

  18. Space environment effect on cell cycle of proliferating FRTL-5 cells

    Science.gov (United States)

    Curcio, Francesco; Saverio Ambesi-Impiombato, Francesco; Meli, Antonella; Perrella, Giuseppina; Spelat, Renza; Zambito, Anna Maria

    The space environment is a unique laboratory to study the response of living organisms to microgravity and cosmic radiation at the molecular and cellular levels. Significant results obtained by us during the Eneide Mission (Soyuz 9S and 10S 2005) showed a different sensitivity to space environment of cells in proliferative state as compared to those in physiological stand-by. The main object of our investigation was to validate these important findings and to study the molecular mechanisms underlying the phenomenon. To this purpose, a cell model of normal cells derived from rat thyroids which can be kept unattended for up to 20 days in a proliferative medium and at room temperature (FRTL-5) were used in a 10 days experiment on a FOTON satellite and in a 15 days experiment in the STS-120 shuttle mission. Experimental design for both flights was planned on the basis of the "ENEIDE" mission results. Microarray analysis has been performed on the samples from Foton M3 and STS-120. Background subtraction, quality assessment and normalization as well as the definition of specific evaluation algorithms have been performed. Based on the hyper G Test function we computed the Hyper geometric p-values for over representation of genes at all Gene Ontology (GO) terms in the induced GO graphs; this test was performed for each GO category and applied also to KEGG pathways. Results show the good quality of the experiment and our data show that the pathways mostly affected by the flight are: a) the cell cycle, b) the ubiquitin mediated proteolysis, c) the repair mechanisms, d) the adherens junction and e) the pyrimidine metabolism. The patways studied indicate that the cells suffer a slowing of cell cycle as well as upregulation of the DNA and RNA repair processes and even further corroborate the validity of using the FRTL5 cells as biosensors for monitoring the effectiveness of countermeasures to damage caused by the Space.

  19. Osthole inhibits proliferation of human breast cancer cells by inducing cell cycle arrest and apoptosis

    Institute of Scientific and Technical Information of China (English)

    Lintao Wang; Yanyan Peng; Kaikai Shi; Haixiao Wang; Jianlei Lu; Yanli Li; Changyan Ma

    2015-01-01

    Recent studies have revealed that osthole,an active constituent isolated from the fruit of Cnidium monnieri (L.) Cusson,a traditional Chinese medicine,possesses anticancer activity.However,its effect on breast cancer cells so far has not been elucidated clearly.In the present study,we evaluated the effects of osthole on the proliferation,cell cycle and apoptosis of human breast cancer cells MDA-MB 435.We demonstrated that osthole is effective in inhibiting the proliferation of MDA-MB 435 cells,The mitochondrion-mediated apoptotic pathway was involved in apoptosis induced by osthole,as indicated by activation of caspase-9 and caspase-3 followed by PARP degradation.The mechanism underlying its effect on the induction of G1 phase arrest was due to the up-regulation of p53 and p21 and down-regulation of Cdk2 and cyclin D1 expression.Were observed taken together,these findings suggest that the anticancer efficacy of osthole is mediated via induction of cell cycle arrest and apoptosis in human breast cancer cells and osthole may be a potential chemotherapeutic agent against human breast cancer.

  20. 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.

  1. Effects of common germ-line genetic variation in cell cycle genes on ovarian cancer survival

    DEFF Research Database (Denmark)

    Song, H.; Hogdall, E.; Ramus, S.J.;

    2008-01-01

    PURPOSE: Somatic alterations have been shown to correlate with ovarian cancer prognosis and survival, but less is known about the effects on survival of common inherited genetic variation. Of particular interest are genes involved in cell cycle pathways, which regulate cell division and could...... plausibly influence clinical characteristics of multiple tumors types. EXPERIMENTAL DESIGN: We examined associations between common germ-line genetic variation in 14 genes involved in cell cycle pathway (CCND1, CCND2, CCND3, CCNE1, CDKN1A, CDKN1B, CDKN2A, CDKN2B, CDKN2C, CDKN2D, CDK2, CDK4, CDK6, and RB1......) and survival among women with invasive ovarian cancer participating in a multicenter case-control study from United Kingdom, Denmark, and United States. DNAs from up to 1,499 women were genotyped for 97 single-nucleotide polymorphisms that tagged the known common variants (minor allele frequency > or = 0...

  2. 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.

  3. Pathway aberrations of murine melanoma cells observed in Paired-End diTag transcriptomes

    International Nuclear Information System (INIS)

    Melanoma is the major cause of skin cancer deaths and melanoma incidence doubles every 10 to 20 years. However, little is known about melanoma pathway aberrations. Here we applied the robust Gene Identification Signature Paired End diTag (GIS-PET) approach to investigate the melanoma transcriptome and characterize the global pathway aberrations. GIS-PET technology directly links 5' mRNA signatures with their corresponding 3' signatures to generate, and then concatenate, PETs for efficient sequencing. We annotated PETs to pathways of KEGG database and compared the murine B16F1 melanoma transcriptome with three non-melanoma murine transcriptomes (Melan-a2 melanocytes, E14 embryonic stem cells, and E17.5 embryo). Gene expression levels as represented by PET counts were compared across melanoma and melanocyte libraries to identify the most significantly altered pathways and investigate the expression levels of crucial cancer genes. Melanin biosynthesis genes were solely expressed in the cells of melanocytic origin, indicating the feasibility of using the PET approach for transcriptome comparison. The most significantly altered pathways were metabolic pathways, including upregulated pathways: purine metabolism, aminophosphonate metabolism, tyrosine metabolism, selenoamino acid metabolism, galactose utilization, nitrobenzene degradation, and bisphenol A degradation; and downregulated pathways: oxidative phosphorylation, ATPase synthesis, TCA cycle, pyruvate metabolism, and glutathione metabolism. The downregulated pathways concurrently indicated a slowdown of mitochondrial activities. Mitochondrial permeability was also significantly altered, as indicated by transcriptional activation of ATP/ADP, citrate/malate, Mg++, fatty acid and amino acid transporters, and transcriptional repression of zinc and metal ion transporters. Upregulation of cell cycle progression, MAPK, and PI3K/Akt pathways were more limited to certain region(s) of the pathway. Expression levels

  4. Pathway aberrations of murine melanoma cells observed in Paired-End diTag transcriptomes

    Directory of Open Access Journals (Sweden)

    Liu Edison

    2007-06-01

    Full Text Available Abstract Background Melanoma is the major cause of skin cancer deaths and melanoma incidence doubles every 10 to 20 years. However, little is known about melanoma pathway aberrations. Here we applied the robust Gene Identification Signature Paired End diTag (GIS-PET approach to investigate the melanoma transcriptome and characterize the global pathway aberrations. Methods GIS-PET technology directly links 5' mRNA signatures with their corresponding 3' signatures to generate, and then concatenate, PETs for efficient sequencing. We annotated PETs to pathways of KEGG database and compared the murine B16F1 melanoma transcriptome with three non-melanoma murine transcriptomes (Melan-a2 melanocytes, E14 embryonic stem cells, and E17.5 embryo. Gene expression levels as represented by PET counts were compared across melanoma and melanocyte libraries to identify the most significantly altered pathways and investigate the expression levels of crucial cancer genes. Results Melanin biosynthesis genes were solely expressed in the cells of melanocytic origin, indicating the feasibility of using the PET approach for transcriptome comparison. The most significantly altered pathways were metabolic pathways, including upregulated pathways: purine metabolism, aminophosphonate metabolism, tyrosine metabolism, selenoamino acid metabolism, galactose utilization, nitrobenzene degradation, and bisphenol A degradation; and downregulated pathways: oxidative phosphorylation, ATPase synthesis, TCA cycle, pyruvate metabolism, and glutathione metabolism. The downregulated pathways concurrently indicated a slowdown of mitochondrial activities. Mitochondrial permeability was also significantly altered, as indicated by transcriptional activation of ATP/ADP, citrate/malate, Mg++, fatty acid and amino acid transporters, and transcriptional repression of zinc and metal ion transporters. Upregulation of cell cycle progression, MAPK, and PI3K/Akt pathways were more limited to certain

  5. 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…

  6. Divergence to apoptosis from ROS induced cell cycle arrest: Effect of cadmium

    International Nuclear Information System (INIS)

    Recently, the role of cadmium (Cd) in immunosupression has gained importance. Nevertheless, the signaling pathways underlying cadmium-induced immune cell death remains largely unclear. In accordance to our previous in vivo report, and to evaluate the further details of the mechanism, we have investigated the effects of cadmium (CdCl2, H2O) on cell cycle regulation and apoptosis in splenocytes in vitro. Our results have revealed that reactive oxygen species (ROS) and p21 are involved in cell cycle arrest in a p53 independent manner but late hour apoptotic response was accompanied by the p53 up-regulation, loss of mitochondrial transmembrane potential (MTP), down-regulation of Bcl-xl, activation of caspase-3 and release of cytochrome c (Cyt c). However, pifithrin alfa (PFT-α), an inhibitor of p53, fails to rescue the cells from the cadmium-induced cell cycle arrest but prevents Bcl-xl down-regulation and loss of Δψm, which indicates that there is an involvement of p53 in apoptosis. In contrast, treatment with N-acetyl cysteine (NAC) can prevent cell cycle arrest and p21 up-regulation at early hours. Although it is clear that, NAC has no effect on apoptosis, p53 expression and MPT changes at late stage events. Taken together, we have demonstrated that cadmium promotes ROS generation, which potently initiates the cell cycle arrest at early hours and finally induces p53-dependent apoptosis at later part of the event.

  7. 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.

  8. 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.

  9. RNA interference regulates the cell cycle checkpoint through the RNA export factor, Ptr1, in fission yeast

    International Nuclear Information System (INIS)

    Highlights: ► RNAi is linked to the cell cycle checkpoint in fission yeast. ► Ptr1 co-purifies with Ago1. ► The ptr1-1 mutation impairs the checkpoint but does not affect gene silencing. ► ago1+ and ptr1+ regulate the cell cycle checkpoint via the same pathway. ► Mutations in ago1+ and ptr1+ lead to the nuclear accumulation of poly(A)+ RNAs. -- Abstract: Ago1, an effector protein of RNA interference (RNAi), regulates heterochromatin silencing and cell cycle arrest in fission yeast. However, the mechanism by which Ago1 controls cell cycle checkpoint following hydroxyurea (HU) treatment has not been elucidated. In this study, we show that Ago1 and other RNAi factors control cell cycle checkpoint following HU treatment via a mechanism independent of silencing. While silencing requires dcr1+, the overexpression of ago1+ alleviated the cell cycle defect in dcr1Δ. Ago1 interacted with the mRNA export factor, Ptr1. The ptr1-1 mutation impaired cell cycle checkpoint but gene silencing was unaffected. Genetic analysis revealed that the regulation of cell cycle checkpoint by ago1+ is dependent on ptr1+. Nuclear accumulation of poly(A)+ RNAs was detected in mutants of ago1+ and ptr1+, suggesting there is a functional link between the cell cycle checkpoint and RNAi-mediated RNA quality control.

  10. Highly proliferative primitive fetal liver hematopoietic stem cells are fueled by oxidative metabolic pathways

    Directory of Open Access Journals (Sweden)

    Javed K. Manesia

    2015-11-01

    Full Text Available Hematopoietic stem cells (HSCs in the fetal liver (FL unlike adult bone marrow (BM proliferate extensively, posing different metabolic demands. However, metabolic pathways responsible for the production of energy and cellular building blocks in FL HSCs have not been described. Here, we report that FL HSCs use oxygen dependent energy generating pathways significantly more than their BM counterparts. RNA-Seq analysis of E14.5 FL versus BM derived HSCs identified increased expression levels of genes involved in oxidative phosphorylation (OxPhos and the citric acid cycle (TCA. We demonstrated that FL HSCs contain more mitochondria than BM HSCs, which resulted in increased levels of oxygen consumption and reactive oxygen species (ROS production. Higher levels of DNA repair and antioxidant pathway gene expression may prevent ROS-mediated (genotoxicity in FL HSCs. Thus, we here for the first time highlight the underestimated importance of oxygen dependent pathways for generating energy and building blocks in FL HSCs.

  11. 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.

  12. Hedgehog signaling acts with the temporal cascade to promote neuroblast cell cycle exit.

    Directory of Open Access Journals (Sweden)

    Phing Chian Chai

    Full Text Available In Drosophila postembryonic neuroblasts, transition in gene expression programs of a cascade of transcription factors (also known as the temporal series acts together with the asymmetric division machinery to generate diverse neurons with distinct identities and regulate the end of neuroblast proliferation. However, the underlying mechanism of how this "temporal series" acts during development remains unclear. Here, we show that Hh signaling in the postembryonic brain is temporally regulated; excess (earlier onset of Hh signaling causes premature neuroblast cell cycle exit and under-proliferation, whereas loss of Hh signaling causes delayed cell cycle exit and excess proliferation. Moreover, the Hh pathway functions downstream of Castor but upstream of Grainyhead, two components of the temporal series, to schedule neuroblast cell cycle exit. Interestingly, hh is likely a target of Castor. Hence, Hh signaling provides a link between the temporal series and the asymmetric division machinery in scheduling the end of neurogenesis.

  13. 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).

  14. Hypoxia Inducible Factor Pathway and Physiological Adaptation: A Cell Survival Pathway?

    Science.gov (United States)

    Kumar, Hemant; Choi, Dong-Kug

    2015-01-01

    Oxygen homeostasis reflects the constant body requirement to generate energy. Hypoxia (0.1-1% O2), physioxia or physoxia (∼1-13%), and normoxia (∼20%) are terms used to define oxygen concentration in the cellular environment. A decrease in oxygen (hypoxia) or excess oxygen (hyperoxia) could be deleterious for cellular adaptation and survival. Hypoxia can occur under both physiological (e.g., exercise, embryonic development, underwater diving, or high altitude) and pathological conditions (e.g., inflammation, solid tumor formation, lung disease, or myocardial infarction). Hypoxia plays a key role in the pathophysiology of heart disease, cancers, stroke, and other causes of mortality. Hypoxia inducible factor(s) (HIFs) are key oxygen sensors that mediate the ability of the cell to cope with decreased oxygen tension. These transcription factors regulate cellular adaptation to hypoxia and protect cells by responding acutely and inducing production of endogenous metabolites and proteins to promptly regulate metabolic pathways. Here, we review the role of the HIF pathway as a metabolic adaptation pathway and how this pathway plays a role in cell survival. We emphasize the roles of the HIF pathway in physiological adaptation, cell death, pH regulation, and adaptation during exercise. PMID:26491231

  15. 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

  16. Olaquindox induces apoptosis through the mitochondrial pathway in HepG2 cells

    International Nuclear Information System (INIS)

    Highlights: → Olaquindox caused cell cycle arrest to the S phase and induced cell apoptosis in HepG2 cells. → Activation of mitochondrial pathways was established by determining the activity of initiator/effector caspases, the levels of PARP, p53 and Bcl-2 family proteins, and the release of cytochrome C from mitochondria. → The results provide a mechanism approach in understanding the characterize of liver damage caused by olaquindox in vitro. -- Abstract: Olaquindox is used in China as feed additive for growth promotion in pigs. Recently, we have demonstrated that olaquindox induced genome DNA damage and oxidative stress in HepG2 cells. The aim of this study was to explore the molecular mechanism of cell cycle arrest and apoptosis induced by olaquindox in HepG2 cells. In the present study olaquindox induced cell cycle arrest to the S phase and dose-dependent apoptotic cell death in HepG2 cells, indicated by accumulation of sub-G1 cell population, nuclear condenstion, DNA fragmentation, caspases activation and PARP cleavage. Meanwhile, the data showed that olaquindox triggered ROS-mediated apoptosis in HepG2 cells correlated with both the mitochondrial DNA damage and nuclear DNA damage, collapse of Δψm, opening of mPTP, down-regulation of Bcl-2 and up-regulation of Bax. Furthermore, we also found that olaquindox increased the expression of p53 protein and induced the release of cytochrome C from mitochondria to cytosol. In conclusion, olaquindox induced apoptosis of HepG2 cells through a caspase-9 and -3 dependent mitochondrial pathway, involving p53, Bcl-2 family protein expression, Δψm disruption and mPTP opening.

  17. 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...

  18. 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.

  19. 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.

  20. 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

  1. 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.

  2. 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.

  3. Application of clinical nursing pathway combined with PDCA cycle in chemotherapy patients with diffuse large B cell lymphoma%临床护理路径结合PDCA循环在弥漫大B细胞淋巴瘤化疗患者中的应用

    Institute of Scientific and Technical Information of China (English)

    黄胜; 许容芳; 姚丹

    2014-01-01

    目的:探讨临床护理路径结合 PDCA 循环在弥漫大 B 细胞淋巴瘤患者化疗中的应用效果。方法将160例行化疗的 DLBCL 患者按入院时间顺序分为2组,对照组80例运用化疗常规工作模式,实验组80例实施临床护理路径结合 PD-CA 循环。比较2组患者健康教育知晓度、对护士工作满意度、不良反应发生情况和平均住院日情况。结果实验组患者健康教育知晓度和对护士工作满意度优于对照组(P <0.05),实验组患者治疗期间不良反应发生情况、平均住院日少于对照组(P <0.05)。结论应用临床护理路径结合 PDCA 循环的标准化管理,可增加患者对疾病的认知能力,提升专科护理质量,提高工作效率和满意度。%0bjective To explore the application of clinical nursing pathway combined with PDCA cycle in chemotherapy patients with diffuse large B cell lymphoma(DLBCL).Methods 160 chemotherapy patients with DLBCL were divided into experimental group and control group, with 80 patients in each group.Patients in the control group were given the conventional chemotherapy and patients in the experimental group were given clinical nursing pathway combined with PDCA cycle.Health education,job satisfaction,the occurrence of adverse reactions and the average hospitalization days were compared between the two groups.Results The awareness of health education and job satisfaction in experimental group were better than that in the control group(P <0.05).The occurrence of adverse reactions and the average hospitalization days in ex-perimental group were lower than that of control group(P <0.05).Conclusion The standard-ized management of clinical nursing pathway combined with PDCA cycle can increase the cognitive ability for diseases and improve the work efficiency as well as satisfaction.

  4. Shared signaling pathways in normal and breast cancer stem cells

    Directory of Open Access Journals (Sweden)

    Gautam K Malhotra

    2011-01-01

    Full Text Available Recent advances in our understanding of breast cancer biology have led to the identification of a subpopulation of cells within tumors that appear to be responsible for initiating and propagating the cancer. These tumor initiating cells are not only unique in their ability to generate tumors, but also share many similarities with elements of normal adult tissue stem cells, and have therefore been termed cancer stem cells (CSCs. These CSCs often inappropriately use many of the same signaling pathways utilized by their normal stem cell counterparts which may present a challenge to the development of CSC specific therapies. Here, we discuss three major stem cell signaling pathways (Notch, Wnt, and Hedgehog; with a focus on their function in normal mammary gland development and their misuse in breast cancer stem cell fate determination.

  5. Control of cell proliferation, endoreduplication, cell size, and cell death by the retinoblastoma-related pathway in maize endosperm

    KAUST Repository

    Sabelli, Paolo A.

    2013-04-22

    The endospermof cereal grains is one of the most valuable products of modern agriculture. Cereal endosperm development comprises different phases characterized by mitotic cell proliferation, endoreduplication, the accumulation of storage compounds, and programmed cell death. Although manipulation of these processes could maximize grain yield, how they are regulated and integrated is poorly understood. We show that the Retinoblastoma-related (RBR) pathway controls key aspects of endosperm development in maize. Down-regulation of RBR1 by RNAi resulted in up-regulation of RBR3-type genes, as well as the MINICHROMOSOME MAINTENANCE 2-7 gene family and PROLIFERATING CELL NUCLEAR ANTIGEN, which encode essential DNA replication factors. Both the mitotic and endoreduplication cell cycles were stimulated. Developing transgenic endosperm contained 42-58% more cells and ~70% more DNA than wild type, whereas there was a reduction in cell and nuclear sizes. In addition, cell death was enhanced. The DNA content of mature endosperm increased 43% upon RBR1 downregulation, whereas storage protein content and kernel weight were essentially not affected. Down-regulation of both RBR1 and CYCLIN DEPENDENT KINASE A (CDKA);1 indicated that CDKA;1 is epistatic to RBR1 and controls endoreduplication through an RBR1- dependent pathway. However, the repressive activity of RBR1 on downstream targets was independent from CDKA;1, suggesting diversification of RBR1 activities. Furthermore, RBR1 negatively regulated CDK activity, suggesting the presence of a feedback loop. These results indicate that the RBR1 pathway plays a major role in regulation of different processes during maize endosperm development and suggest the presence of tissue/organlevel regulation of endosperm/seed homeostasis.

  6. Pathways to a New Efficiency Regime for Organic Solar Cells

    NARCIS (Netherlands)

    Koster, L. Jan Anton; Shaheen, Sean E.; Hummelen, Jan C.

    2012-01-01

    Three different theoretical approaches are presented to identify pathways to organic solar cells with power conversion efficiencies in excess of 20%. A radiation limit for organic solar cells is introduced that elucidates the role of charge-transfer (CT) state absorption. Provided this CT action is

  7. Musashi2 modulates K562 leukemic cell proliferation and apoptosis involving the MAPK pathway

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Huijuan; Tan, Shi; Wang, Juan; Chen, Shana; Quan, Jing; Xian, Jingrong; Zhang, Shuai shuai; He, Jingang; Zhang, Ling, E-mail: lingzhang@cqmu.edu.cn

    2014-01-01

    The RNA-binding protein Musashi2 (Msi2) has been identified as a master regulator within a variety of stem cell populations via the regulation of translational gene expression. A recent study has suggested that Msi2 is strongly expressed in leukemic cells of acute myeloid leukemia patients, and elevated Msi2 is associated with poor prognosis. However, the potential role of Msi2 in leukemogenesis is still not well understood. Here, we investigated the effect of Msi2 knockdown on the biological properties of leukemic cells. High expression of Msi2 was found in K562 and KG-1a leukemic cell lines, and low expression was observed in the U937 cell line. We transduced K562 cells with two independent adenoviral shRNA vectors targeting Msi2 and confirmed knockdown of Msi2 at the mRNA and protein levels. Msi2 silencing inhibited cell growth and caused cell cycle arrest by increasing the expression of p21 and decreasing the expression of cyclin D1 and cdk2. In addition, knockdown of Msi2 promoted cellular apoptosis via the upregulation of Bax and downregulation of Bcl-2 expression. Furthermore, Msi2 knockdown resulted in the inactivation of the ERK/MAPK and p38/MAPK pathways, but no remarkable change in p-AKT was observed. These data provide evidence that Msi2 plays an important role in leukemogenesis involving the MAPK signaling pathway, which indicates that Msi2 may be a novel target for leukemia treatment. - Highlights: • Knockdown of Msi2 inhibited K562 cell growth and arrested cell cycle progression. • Knockdown of Msi2 induced K562 cell apoptosis via the regulation of Bax and Bcl-2. • The MAPK pathway was involved in the process of Msi2-mediated leukemogenesis. • Our data indicate that Msi2 is a potential new target for leukemia treatment.

  8. Targeting glioma stem cells via the Hedgehog signaling pathway

    Directory of Open Access Journals (Sweden)

    Yang Liu

    2014-09-01

    Full Text Available Cancer is one of the leading causes of death worldwide. Gliomas are among the most devastating tumor types, and current clinical therapies are unsatisfactory. Recent reports revealed the importance of glioma-propagating cells in the malignancy of gliomas. These cells, also referred to as glioma stem cells (GSCs, share similarities with neural stem cells (NSCs. The Hedgehog (Hh signaling pathway controls tissue polarity, patterning maintenance, and maintenance of NSCs during embryonic development. Aberrant activation of the Hh pathway resulting from mutation and deregulation has recently been recognized to cause tumorigenesis in a wide variety of tissues, including gliomas and GSCs. In this review, we explore the role of the Hh signaling pathway in GSCs and its potential as a therapeutic strategy.

  9. Calcium signaling and T-type calcium channels in cancer cell cycling

    Institute of Scientific and Technical Information of China (English)

    James T Taylor; Xiang-Bin Zeng; Jonathan E Pottle; Kevin Lee; Alun R Wang; Stephenie G Yi; Jennifer A S Scruggs; Suresh S Sikka; Ming Li

    2008-01-01

    Regulation of intracellular calcium is an important signaling mechanism for cell proliferation in both normal and cancerous cells. In normal epithelial cells,free calcium concentration is essential for cells to enter and accomplish the S phase and the M phase of the cell cycle. In contrast, cancerous cells can pass these phases of the cell cycle with much lower cytoplasmic free calcium concentrations, indicating an alternative mechanism has developed for fulfilling the intracellular calcium requirement for an increased rate of DNA synthesis and mitosis of fast replicating cancerous cells. The detailed mechanism underlying the altered calcium loading pathway remains unclear;however, there is a growing body of evidence that suggests the T-type Ca2+ channel is abnormally expressed in cancerous cells and that blockade of these channels may reduce cell proliferation in addition to inducing apoptosis. Recent studies also show that the expression of T-type Ca2+ channels in breast cancer cells is proliferation state dependent, i.e. the channels are expressed at higher levels during the fast-replication period, and once the cells are in a non-proliferation state, expression of this channel isminimal. Therefore, selectively blocking calcium entry into cancerous cells may be a valuable approach for preventing tumor growth. Since T-type Ca2+ channels are not expressed in epithelial cells, selective T-type Ca2+ channel blockers may be useful in the treatment of certain types of cancers.

  10. 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...

  11. Mushroom extract increases p53 expression and causes cell cycle arrest and apoptosis in a breast cancer cell line

    OpenAIRE

    Vaz, Josiana A.; Tavares, Catarina; Almeida, Gabriela M.; Martins, Anabela; Ferreira, Isabel C. F. R.; Vasconcelos, M. Helena

    2012-01-01

    Mushrooms are part of the sexual life cycle of particular fungi with specific metabolic pathways, and therefore may contain a largely unexploited source of powerful new pharmaceutical products with potential antitumor properties [1,2]. Furthermore, they may have potential as functional foods. Suillus collinitus is an edible mushroom found in European pine forests. The aim of this work was to study the cytotoxic potential of extracts from this mushroom in various cancer cell lines....

  12. Platycodin D induced apoptosis and autophagy in PC-12 cells through mitochondrial dysfunction pathway.

    Science.gov (United States)

    Zeng, Chuan-Chuan; Zhang, Cheng; Yao, Jun-Hua; Lai, Shang-Hai; Han, Bing-Jie; Li, Wei; Tang, Bing; Wan, Dan; Liu, Yun-Jun

    2016-11-01

    In this article, the in vitro cytotoxicity of platycodin D was evaluated in human PC-12, SGC-7901, BEL-7402, HeLa and A549 cancer cell lines. PC-12 cells were sensitive to platycodin D treatment, with an IC50 value of 13.5±1.2μM. Morphological and comet assays showed that platycodin D effectively induced apoptosis in PC-12 cells. Platycodin D increased the levels of reactive oxygen species (ROS) and induced a decrease in mitochondrial membrane potential. Platycodin D induced cell cycle arrest at the G0/G1 phase in the PC-12 cell line. Platycodin D can induce autophagy. In addition, platycodin D can down-regulate the expression of Bcl-2 and Bcl-x, and up-regulate the levels of Bid protein in the PC-12 cells. The results demonstrated that platycodin D induced PC-12 cell apoptosis through a ROS-mediated mitochondrial dysfunction pathway. PMID:27294548

  13. [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

  14. 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.

  15. Novel Hedgehog pathway targets against Basal Cell Carcinoma

    OpenAIRE

    Tang, Jean Y.; So, Po-Lin; Epstein, Ervin H.

    2006-01-01

    The Hedgehog signaling pathway plays a key role in directing growth and patterning during embryonic development and is required in vertebrates for the normal development of many structures, including the neural tube, axial skeleton, skin, and hair. Aberrant activation of the Hedgehog (Hh) pathway in adult tissue is associated with the development of basal cell carcinoma (BCC), medulloblastoma, and a subset of pancreatic, gastro-intestinal, and other cancers. This review will provide an overvi...

  16. 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 ...

  17. 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

  18. 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.

  19. Paris chinensis dioscin induces G2/M cell cycle arrest and apoptosis in human gastric cancer SGC-7901 cells

    Institute of Scientific and Technical Information of China (English)

    Lin-Lin Gao; Fu-Rong Li; Peng Jiao; Ming-Feng Yang; Xiao-Jun Zhou; Yan-Hong Si; Wen-Jian Jiang; Ting-Ting Zheng

    2011-01-01

    AIM: To investigate the anti-tumor effects of Paris chinensis dioscin (PCD) and mechanisms regarding cell cycle regulation and apoptosis in human gastric cancer SGC-7901 cells.METHODS: Cell viability was analyzed by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-tetrazolium bromide assay. Cell apoptosis was evaluated by flow cytometry and laser scanning confocal microscope (LSCM) using Annexin-V/propidium iodide (PI) staining, and the cell cycle was evaluated using PI staining with flow cytometry. Intracellular calcium ions were detected under fluorescence microscope. The expression of cell cycle and apoptosis-related proteins cyclin B1, CDK1, cytochrome C and caspase-3 was measured by immunohistochemical staining. RESULTS: PCD had an anti-proliferation effect on human gastric cancer SGC-7901 cells in a dose- and time-dependent manner. After treatment of SGC-7901 cells with PCD, apoptosis appeared in SGC-7901 cells. Morphological changes typical of apoptosis were also observed with LSCM by Annexin V/PI staining, and the cell number of the G0/G1 phase was decreased, while the number of cells in the G2/M phase was increased. Cell cycle-related proteins, such as cyclin B1 and CDK1, were all down-regulated, but caspase-3 and cytochrome C were up-regulated. Moreover, intracellular calcium accumulation occurred in PCD-treated cells. CONCLUSION: G2/M phase arrest and apoptosis induced by PCD are associated with the inhibition of CDK-activating kinase activity and the activation of Ca2+-related mitochondrion pathway in SGC-7901 cells.

  20. 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...

  1. Honokiol induces apoptosis through p53-independent pathway in human colorectal cell line RKO

    Institute of Scientific and Technical Information of China (English)

    Tao Wang; Fei Chen; Zhe Chen; Yi-Feng Wu; Xiao-Li Xu; Shu Zheng; Xun Hu

    2004-01-01

    AIM: To investigate the signal pathway of honokiol-induced apoptosis on human colorectal carcinoma RKO cells and to evaluate whether p53 and p53-related genes were involved in honokiol-treated RKO cells.METHODS: Cell cycle distribution and subdiploid peak were analyzed with a flow cytometer and DNA fragment with electrophoresis on agarose gels. Transcriptional level of Bax, Bcl-2, Bid and Bcl-xl was accessed by RT-PCR.Western blotting was used to measure p53 protein expression and other factors related to apoptosis.Proliferation inhibition of two cell lines (RKO, SW480) with high expression of p53 and one cell line with p53 negative expression (LS180) was monitored by MTT assay.RESULTS: Honokiol induced RKO cell apoptosis in a dosedependent manner. The mRNA expression level and protein level of Bid were up-regulated while that of Bcl-xl was down-regulated, but no changes in Bax and Bcl-2 were observed. Western blotting showed p53 expression had no remarkable changes in honokiol-induced RKO cell apoptosis. LS180 cells treated with honokiol exhibited apparent growth inhibition like RKO cells and Sw480 cells.CONCLUSION: Honokiol can induce RKO cells apoptosis through activating caspase cascade by p53-indepenent pathway.

  2. Neocarzinostatin-induced Rad51 nuclear focus formation is cell cycle regulated and aberrant in AT cells

    International Nuclear Information System (INIS)

    DNA double-stranded breaks are the most detrimental form of DNA damage and, if not repaired properly, may lead to an accumulation of chromosomal aberrations and eventually tumorigenesis. Proteins of the Rad51/Rad52 epitasis group are crucial for the recombinational repair of DNA double-stranded breaks, whereas the Rad50/NBS1/Mre11 nuclease complex is involved in both the recombinational and the end-joining repair of DNA double-stranded breaks. Herein, we demonstrate that the chemotherapeutic enediyne antibiotic neocarzinostatin induced Rad51, but not NBS1, nuclear focus formation in a cell- cycle-dependent manner. Furthermore, neocarzinostatin-induced Rad51 foci formation revealed a slower kinetic change in AT cells, but not in wild-type or NBS cells. In summary, our results suggest that neocarzinostatin induces Rad51 focus formation through an ATM- and cell-cycle-dependent, but NBS1-independent, pathway

  3. 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.

  4. Toll-like receptor 4 is involved in the cell cycle modulation and required for effective human cytomegalovirus infection in THP-1 macrophages

    Energy Technology Data Exchange (ETDEWEB)

    Arcangeletti, Maria-Cristina, E-mail: mariacristina.arcangeletti@unipr.it [Department of Clinical and Experimental Medicine, University of Parma, Parma (Italy); Germini, Diego; Rodighiero, Isabella [Department of Clinical and Experimental Medicine, University of Parma, Parma (Italy); Mirandola, Prisco [Department of Biomedical, Biotechnological and Translational Sciences, University of Parma, Parma (Italy); De Conto, Flora; Medici, Maria-Cristina [Department of Clinical and Experimental Medicine, University of Parma, Parma (Italy); Gatti, Rita [Department of Biomedical, Biotechnological and Translational Sciences, University of Parma, Parma (Italy); Chezzi, Carlo; Calderaro, Adriana [Department of Clinical and Experimental Medicine, University of Parma, Parma (Italy)

    2013-05-25

    Suitable host cell metabolic conditions are fundamental for the effective development of the human cytomegalovirus (HCMV) lytic cycle. Indeed, several studies have demonstrated the ability of this virus to interfere with cell cycle regulation, mainly by blocking proliferating cells in G1 or G1/S. In the present study, we demonstrate that HCMV deregulates the cell cycle of THP-1 macrophages (a cell line irreversibly arrested in G0) by pushing them into S and G2 phases. Moreover, we show that HCMV infection of THP-1 macrophages leads to Toll-like receptor 4 (TLR4) activation. Since various studies have indicated TLR4 to be involved in promoting cell proliferation, here we investigate the possible role of TLR4 in the observed HCMV-induced cell cycle perturbation. Our data strongly support TLR4 as a mediator of HCMV-triggered cell cycle activation in THP-1 macrophages favouring, in turn, the development of an efficient viral lytic cycle. - Highlights: ► We studied HCMV infection impact on THP-1 macrophage cell cycle. ► We analysed the role played by Toll-like receptor (TLR) 4 upon HCMV infection. ► HCMV pushes THP-1 macrophages (i.e. resting cells) to re-enter the cell cycle. ► TLR4 pathway inhibition strongly affects the effectiveness of HCMV replication. ► TLR4 pathway inhibition significantly decreases HCMV-induced cell cycle re-entry.

  5. Toll-like receptor 4 is involved in the cell cycle modulation and required for effective human cytomegalovirus infection in THP-1 macrophages

    International Nuclear Information System (INIS)

    Suitable host cell metabolic conditions are fundamental for the effective development of the human cytomegalovirus (HCMV) lytic cycle. Indeed, several studies have demonstrated the ability of this virus to interfere with cell cycle regulation, mainly by blocking proliferating cells in G1 or G1/S. In the present study, we demonstrate that HCMV deregulates the cell cycle of THP-1 macrophages (a cell line irreversibly arrested in G0) by pushing them into S and G2 phases. Moreover, we show that HCMV infection of THP-1 macrophages leads to Toll-like receptor 4 (TLR4) activation. Since various studies have indicated TLR4 to be involved in promoting cell proliferation, here we investigate the possible role of TLR4 in the observed HCMV-induced cell cycle perturbation. Our data strongly support TLR4 as a mediator of HCMV-triggered cell cycle activation in THP-1 macrophages favouring, in turn, the development of an efficient viral lytic cycle. - Highlights: ► We studied HCMV infection impact on THP-1 macrophage cell cycle. ► We analysed the role played by Toll-like receptor (TLR) 4 upon HCMV infection. ► HCMV pushes THP-1 macrophages (i.e. resting cells) to re-enter the cell cycle. ► TLR4 pathway inhibition strongly affects the effectiveness of HCMV replication. ► TLR4 pathway inhibition significantly decreases HCMV-induced cell cycle re-entry

  6. 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.

  7. 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.

  8. The combinatorial activation of the PI3K and Ras/MAPK pathways is sufficient for aggressive tumor formation, while individual pathway activation supports cell persistence.

    Science.gov (United States)

    Thompson, Keyata N; Whipple, Rebecca A; Yoon, Jennifer R; Lipsky, Michael; Charpentier, Monica S; Boggs, Amanda E; Chakrabarti, Kristi R; Bhandary, Lekhana; Hessler, Lindsay K; Martin, Stuart S; Vitolo, Michele I

    2015-11-01

    A high proportion of human tumors maintain activation of both the PI3K and Ras/MAPK pathways. In basal-like breast cancer (BBC), PTEN expression is decreased/lost in over 50% of cases, leading to aberrant activation of the PI3K pathway. Additionally, BBC cell lines and tumor models have been shown to exhibit an oncogenic Ras-like gene transcriptional signature, indicating activation of the Ras/MAPK pathway. To directly test how the PI3K and Ras/MAPK pathways contribute to tumorigenesis, we deleted PTEN and activated KRas within non-tumorigenic MCF-10A breast cells. Neither individual mutation was sufficient to promote tumorigenesis, but the combination promoted robust tumor growth in mice. However, in vivo bioluminescence reveals that each mutation has the ability to promote a persistent phenotype. Inherent in the concept of tumor cell dormancy, a stage in which residual disease is present but remains asymptomatic, viable cells with each individual mutation can persist in vivo during a period of latency. The persistent cells were excised from the mice and showed increased levels of the cell cycle arrest proteins p21 and p27 compared to the aggressively growing PTEN-/-KRAS(G12V) cells. Additionally, when these persistent cells were placed into growth-promoting conditions, they were able to re-enter the cell cycle and proliferate. These results highlight the potential for either PTEN loss or KRAS activation to promote cell survival in vivo, and the unique ability of the combined mutations to yield rapid tumor growth. This could have important implications in determining recurrence risk and disease progression in tumor subtypes where these mutations are common. PMID:26497685

  9. Cell cycle networks link gene expression dysregulation, mutation, and brain maldevelopment in autistic toddlers.

    Science.gov (United States)

    Pramparo, Tiziano; Lombardo, Michael V; Campbell, Kathleen; Barnes, Cynthia Carter; Marinero, Steven; Solso, Stephanie; Young, Julia; Mayo, Maisi; Dale, Anders; Ahrens-Barbeau, Clelia; Murray, Sarah S; Lopez, Linda; Lewis, Nathan; Pierce, Karen; Courchesne, Eric

    2015-12-01

    Genetic mechanisms underlying abnormal early neural development in toddlers with Autism Spectrum Disorder (ASD) remain uncertain due to the impossibility of direct brain gene expression measurement during critical periods of early development. Recent findings from a multi-tissue study demonstrated high expression of many of the same gene networks between blood and brain tissues, in particular with cell cycle functions. We explored relationships between blood gene expression and total brain volume (TBV) in 142 ASD and control male toddlers. In control toddlers, TBV variation significantly correlated with cell cycle and protein folding gene networks, potentially impacting neuron number and synapse development. In ASD toddlers, their correlations with brain size were lost as a result of considerable changes in network organization, while cell adhesion gene networks significantly correlated with TBV variation. Cell cycle networks detected in blood are highly preserved in the human brain and are upregulated during prenatal states of development. Overall, alterations were more pronounced in bigger brains. We identified 23 candidate genes for brain maldevelopment linked to 32 genes frequently mutated in ASD. The integrated network includes genes that are dysregulated in leukocyte and/or postmortem brain tissue of ASD subjects and belong to signaling pathways regulating cell cycle G1/S and G2/M phase transition. Finally, analyses of the CHD8 subnetwork and altered transcript levels from an independent study of CHD8 suppression further confirmed the central role of genes regulating neurogenesis and cell adhesion processes in ASD brain maldevelopment. PMID:26668231

  10. 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...

  11. Mast cell chemotaxis - chemoattractants and signaling pathways

    Czech Academy of Sciences Publication Activity Database

    Hálová, Ivana; Dráberová, Lubica; Dráber, Petr

    2012-01-01

    Roč. 3, May (2012), s. 119. ISSN 1664-3224 R&D Projects: GA MŠk LD12073; GA ČR GA301/09/1826; GA ČR GAP302/10/1759 Grant ostatní: ECST(XE) BM1007; AV ČR(CZ) MC200520901 Institutional support: RVO:68378050 Keywords : mast cell * IgE receptor * plasma membrane Subject RIV: EB - Genetics ; Molecular Biology

  12. 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.

  13. Signaling pathways involved in megakaryocyte-mediated proliferation of osteoblast lineage cells.

    Science.gov (United States)

    Cheng, Ying-Hua; Streicher, Drew A; Waning, David L; Chitteti, Brahmananda R; Gerard-O'Riley, Rita; Horowitz, Mark C; Bidwell, Joseph P; Pavalko, Fredrick M; Srour, Edward F; Mayo, Lindsey D; Kacena, Melissa A

    2015-03-01

    Recent studies suggest that megakaryocytes (MKs) may play a significant role in skeletal homeostasis, as evident by the occurrence of osteosclerosis in multiple MK related diseases (Lennert et al., 1975; Thiele et al., 1999; Chagraoui et al., 2006). We previously reported a novel interaction whereby MKs enhanced proliferation of osteoblast lineage/osteoprogenitor cells (OBs) by a mechanism requiring direct cell-cell contact. However, the signal transduction pathways and the downstream effector molecules involved in this process have not been characterized. Here we show that MKs contact with OBs, via beta1 integrin, activate the p38/MAPKAPK2/p90RSK kinase cascade in the bone cells, which causes Mdm2 to neutralizes p53/Rb-mediated check point and allows progression through the G1/S. Interestingly, activation of MAPK (ERK1/2) and AKT, collateral pathways that regulate the cell cycle, remained unchanged with MK stimulation of OBs. The MK-to-OB signaling ultimately results in significant increases in the expression of c-fos and cyclin A, necessary for sustaining the OB proliferation. Overall, our findings show that OBs respond to the presence of MKs, in part, via an integrin-mediated signaling mechanism, activating a novel response axis that de-represses cell cycle activity. Understanding the mechanisms by which MKs enhance OB proliferation will facilitate the development of novel anabolic therapies to treat bone loss associated with osteoporosis and other bone-related diseases. PMID:25160801

  14. PI3K/Akt/mTOR pathway inhibitors enhance radiosensitivity in radioresistant prostate cancer cells through inducing apoptosis, reducing autophagy, suppressing NHEJ and HR repair pathways.

    Science.gov (United States)

    Chang, L; Graham, P H; Hao, J; Ni, J; Bucci, J; Cozzi, P J; Kearsley, J H; Li, Y

    2014-01-01

    The PI3K/Akt/mTOR pathway has a central role in cancer metastasis and radiotherapy. To develop effective therapeutics to improve radiosensitivity, understanding the possible pathways of radioresistance involved and the effects of a combination of the PI3K/Akt/mTOR inhibitors with radiotherapy on prostate cancer (CaP) radioresistant cells is needed. We found that compared with parent CaP cells, CaP-radioresistant cells demonstrated G0/G1 and S phase arrest, activation of cell cycle check point, autophagy and DNA repair pathway proteins, and inactivation of apoptotic proteins. We also demonstrated that compared with combination of single PI3K or mTOR inhibitors (BKM120 or Rapamycin) and radiation, low-dose of dual PI3K/mTOR inhibitors (BEZ235 or PI103) combined with radiation greatly improved treatment efficacy by repressing colony formation, inducing more apoptosis, leading to the arrest of the G2/M phase, increased double-strand break levels and less inactivation of cell cycle check point, autophagy and non-homologous end joining (NHEJ)/homologous recombination (HR) repair pathway proteins in CaP-radioresistant cells. This study describes the possible pathways associated with CaP radioresistance and demonstrates the putative mechanisms of the radiosensitization effect in CaP-resistant cells in the combination treatment. The findings from this study suggest that the combination of dual PI3K/Akt/mTOR inhibitors (BEZ235 or PI103) with radiotherapy is a promising modality for the treatment of CaP to overcome radioresistance. PMID:25275598

  15. Comparison of Algal Biodiesel Production Pathways Using Life Cycle Assessment Tool

    DEFF Research Database (Denmark)

    Singh, Anoop; Olsen, Stig Irving

    2013-01-01

    The consideration of algal biomass in biodiesel production increased very rapidly in the last decade. A life cycle assessment (LCA) study is presented to compare six different biodiesel production pathways (three different harvesting techniques, i.e., aluminum as flocculent, lime flocculent, and...... centrifugation, and two different oil extraction methods, i.e., supercritical CO2 (sCO2) and press and co-solvent extraction). The cultivation of Nannochloropsis sp. considered in a flat-panel photobioreactor (FPPBR). These algal biodiesel production systems were compared with the conventional diesel in a EURO 5...... passenger car used for transport purpose (functional unit 1 person km (pkm). The algal biodiesel production systems provide lesser impact (22–105 %) in comparison with conventional diesel. Impacts of algal biodiesel on climate change were far better than conventional diesel, but impacts on human health...

  16. 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

  17. 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...

  18. Pomegranate peel extract polyphenols induced apoptosis in human hepatoma cells by mitochondrial pathway.

    Science.gov (United States)

    Song, Bingbing; Li, Jia; Li, Jianke

    2016-07-01

    This study was aimed to investigate the influence of pomegranate peel polyphenols (PPPs) on the proliferation and apoptosis of HepG2 cells (a kind of human hepatoma cells) and the related mechanism. The inverted fluorescence microscope and the flow cytometer (FCM) were used to test the changes of the cellular morphology, cell cycle, apoptosis, reactive oxygen species (ROS) and mitochondrial transmembrane potential (Δψm). The kit was used to measure the activities of caspase-3/9, and Western Blot was used to detect the expressions of apoptosis-associated proteins including p53, Bcl-2/Bax, Cyt-c and PARP. The results showed that the cells cycle of HepG2 arrested at the S-phase by PPPs and the amount of the early apoptotic cells and ROS level were increased obviously, the level of Cyt-c and the activity of Caspase-3/9 markedly were also increased by PPPs, as well as the ratio of Bax/Bcl-2 and the protein expressions of P53. It was concluded that PPPs could inhibit the growth of HepG2 cells by blocking the cell cycle and inducing the mitochondrial apoptotic pathway in a dose-dependent manner. PMID:27120393

  19. 3, 3', 4, 4', 5-pentachlorobiphenyl (PCB 126) deregulates proliferation of contact-inhibited rat liver epithelial 'stem-like' cells via aryl hydrocarbon receptor - effects on cell cycle regulators, cell-to-cell communication and interactions with other signaling pathways

    Czech Academy of Sciences Publication Activity Database

    Vondráček, Jan; Zatloukalová, Jiřina; Umannová, Lenka; Bryja, Vítězslav; Krčmář, P.; Kozubík, Alois; Dietrich, C.; Machala, M.

    Seattle, 2008. s. 250. [47th Annual Meeting of the Society of Toxicology. 16.03.2008-20.03.2008, Seattle] R&D Projects: GA ČR(CZ) GA524/06/0517 Institutional research plan: CEZ:AV0Z50040507; CEZ:AV0Z50040702 Keywords : AhR * cell proliferation * tumor promotion Subject RIV: BO - Biophysics

  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. Differences in gene expression and alterations in cell cycle of acute myeloid leukemia cell lines after treatment with JAK inhibitors.

    Science.gov (United States)

    Gunerka, Pawel; Dymek, Barbara; Stanczak, Aleksandra; Bujak, Anna; Grygielewicz, Paulina; Turowski, Pawel; Dzwonek, Karolina; Lamparska-Przybysz, Monika; Pietrucha, Tadeusz; Wieczorek, Maciej

    2015-10-15

    Janus kinase (JAK) inhibitors are a promising treatment strategy in several hematological malignancies and autoimmune diseases. A number of inhibitors are in clinical development, and two have already reached the market. Unfortunately, all of them are burdened with different toxicity profiles. To check if the JAK inhibitors of different selectivity evoke different responses on JAK2-dependent and independent cells, we have used three acute myeloid leukemia cell lines with confirmed JAK2 mutation status. We have found that JAK inhibitors exert distinct effect on the expression of BCLXL, CCND1 and c-MYC genes, regulated by JAK pathway, in JAK2 wild type cells in comparison to JAK2 V617F-positive cell lines. Moreover, cell cycle analysis showed that inhibitors alter the cycle by arresting cells in different phases. Our results suggest that observed effect of JAK2 inhibitors on transcription and cell cycle level in different cell lines are associated not with activity within JAK family, but presumably with other off-target activities. PMID:26300391

  2. 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...

  3. Resveratrol enhances prostate cancer cell response to ionizing radiation. Modulation of the AMPK, Akt and mTOR pathways

    International Nuclear Information System (INIS)

    Prostate cancer (PrCa) displays resistance to radiotherapy (RT) and requires radiotherapy dose escalation which is associated with greater toxicity. This highlights a need to develop radiation sensitizers to improve the efficacy of RT in PrCa. Ionizing radiation (IR) stimulates pathways of IR-resistance and survival mediated by the protein kinase Akt but it also activates the metabolic energy sensor and tumor suppressor AMP-Activated Protein Kinase (AMPK). Here, we examined the effects of the polyphenol resveratrol (RSV) on the IR-induced inhibition of cell survival, modulation of cell cycle and molecular responses in PrCa cells. Androgen-insensitive (PC3), sensitive (22RV1) PrCa and PNT1A normal prostate epithelial cells were treated with RSV alone (2.5-10 μM) or in combination with IR (2-8 Gy). Clonogenic assays, cell cycle analysis, microscopy and immunoblotting were performed to assess survival, cell cycle progression and molecular responses. RSV (2.5-5 μM) inhibited clonogenic survival of PC3 and 22RV1 cells but not of normal prostate PNT1A cells. RSV specifically sensitized PrCa cells to IR, induced cell cycle arrest at G1-S phase and enhanced IR-induced nuclear aberrations and apoptosis. RSV enhanced IR-induced expression of DNA damage (γH2Ax) and apoptosis (cleaved-caspase 3) markers as well as of the cell cycle regulators p53, p21cip1 and p27kip1. RSV enhanced IR-activation of ATM and AMPK but inhibited basal and IR-induced phosphorylation of Akt. Our results suggest that RSV arrests cell cycle, promotes apoptosis and sensitizes PrCa cells to IR likely through a desirable dual action to activate the ATM-AMPK-p53-p21cip1/p27kip1 and inhibit the Akt signalling pathways

  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. 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)

  7. Photodynamic therapy activated STAT3 associated pathways: Targeting intrinsic apoptotic pathways to increase PDT efficacy in human squamous carcinoma cells.

    Science.gov (United States)

    Qiao, Li; Xu, Chengshan; Li, Qiang; Mei, Zhusong; Li, Xinji; Cai, Hong; Liu, Wei

    2016-06-01

    5-Aminolaevulinic acid-based photodynamic therapy (ALA-PDT) has been used for part of squamous cell carcinoma (premalignant conditions or in situ cutaneous SCC-Bowen disease). However, mechanism of ALA-PDT is not fully understood yet on the cell apoptosis pathway. The aim of this study was to further investigate the effect and mechanism of 5-ALA-PDT on human squamous carcinoma A431cells. Apoptosis and cell viability after PDT were evaluated using Annexin V-FITC apoptosis detection kit and MTT assay. The mRNA and protein levels were detected by quantitative real-time polymerase chain reaction (qRT-PCR) and Western blot. Our data showed that 5-ALA-PDT significantly inhibited cell proliferation (p<0.05), but there was no significant difference when the photosensitizer reached to 4.8mM. The inhibition in cell proliferation after 5-ALA-PDT treatment was correlated to more cells being arrested in the G0/G1 phase of the cell cycle (p<0.01). Immunocytochemical observations using anti-active caspase-3 antibodies showed active caspase-3 was translocated from cytoplasm to nuclear during apoptosis. STAT3 and its downstream gene Bax and BCL-2 were changed after 5-ALA-PDT treatment for the mRNA and protein expression. Our studies confirmed that 5-ALA-PDT might be an effective treatment for human squamous carcinoma by inhibiting the tumor cell A431growth and for the first time demonstrated that the expression of STAT3 was significantly reduced at 24h after 5-ALA-PDT treatment. PMID:26607555

  8. Inhibitors targeting on cell wall biosynthesis pathway of MRSA.

    Science.gov (United States)

    Hao, Haihong; Cheng, Guyue; Dai, Menghong; Wu, Qinghua; Yuan, Zonghui

    2012-11-01

    Methicillin resistant Staphylococcus aureus (MRSA), widely known as a type of new superbug, has aroused world-wide concern. Cell wall biosynthesis pathway is an old but good target for the development of antibacterial agents. Peptidoglycan and wall teichoic acids (WTAs) biosynthesis are two main processes of the cell wall biosynthesis pathway (CWBP). Other than penicillin-binding proteins (PBPs), some key factors (Mur enzymes, lipid I or II precursor, etc.) in CWBP are becoming attractive molecule targets for the discovery of anti-MRSA compounds. A number of new compounds, with higher affinity for PBPs or with inhibitory activity on such molecule targets in CWBP of MRSA, have been in the pipeline recently. This review concludes recent research achievements and provides a complete picture of CWBP of MRSA, including the peptidoglycan and wall teichoic acids synthesis pathway. The potential inhibitors targeting on CWBP are subsequently presented to improve development of novel therapeutic strategies for MRSA. PMID:22898792

  9. Genistein Enhances the Radiosensitivity of Breast Cancer Cells via G2/M Cell Cycle Arrest and Apoptosis

    Directory of Open Access Journals (Sweden)

    Li Gong

    2013-10-01

    Full Text Available The aim of the present study was to investigate the radiosensitizing effect of genistein, and the corresponding mechanisms of action on breast cancer cells with different estrogen receptor (ER status. Human breast cancer cell lines such as MCF-7 (ER-positive, harboring wild-type p53 and MDA-MB-231 (ER-negative, harboring mutant p53 were irradiated with X-rays in the presence or absence of genistein. Cell survival, DNA damage and repair, cell cycle distribution, cell apoptosis, expression of proteins related to G2/M cell cycle checkpoint and apoptosis were measured with colony formation assays, immunohistochemistry, flow cytometry and western blot analysis, respectively. Genistein showed relatively weak toxicity to both cell lines at concentrations in the range of 5–20 μM. Using the dosage of 10 μM genistein, the sensitizer enhancement ratios after exposure to X-rays at a 10% cell survival (IC10 were 1.43 for MCF-7 and 1.36 for MDA-MB-231 cells, respectively. Significantly increased DNA damages, arrested cells at G2/M phase, decreased homologous recombination repair protein Rad51 foci formation and enhanced apoptotic rates were observed in both cell lines treated by genistein combined with X-rays compared with the irradiation alone. The combined treatment obviously up-regulated the phosphorylation of ATM, Chk2, Cdc25c and Cdc2, leading to permanent G2/M phase arrest, and up-regulated Bax and p73, down-regulated Bcl-2, finally induced mitochondria-mediated apoptosis in both cell lines. These results suggest that genistein induces G2/M arrest by the activation of the ATM/Chk2/Cdc25C/Cdc2 checkpoint pathway and ultimately enhances the radiosensitivity of both ER+ and ER- breast cancer cells through a mitochondria-mediated apoptosis pathway.

  10. Cell volume homeostatic mechanisms: effectors and signalling pathways

    DEFF Research Database (Denmark)

    Hoffmann, E K; Pedersen, Stine Helene Falsig

    2011-01-01

    the historical context of studies of cell volume regulation, focusing on the lineage started by Krogh, Bodil Schmidt-Nielsen, Hans-Henrik Ussing, and their students. The early work was focused on understanding the functional behaviour, kinetics and thermodynamics of the volume-regulatory ion transport......Cell volume homeostasis and its fine-tuning to the specific physiological context at any given moment are processes fundamental to normal cell function. The understanding of cell volume regulation owes much to August Krogh, yet has advanced greatly over the last decades. In this review, we outline...... mechanisms. Later work addressed the mechanisms through which cellular signalling pathways regulate the volume regulatory effectors or flux pathways. These studies were facilitated by the molecular identification of most of the relevant channels and transporters, and more recently also by the increased...

  11. Nuclear fuel cycle: estimation of physical impacts and monetary valuation for priority pathways

    International Nuclear Information System (INIS)

    The decision-making process for setting future energy policy requires a large range of information. An important component in this process is the comparison of the various costs incurred by the different types of energy systems. Among these costs are those that the production and consumption of energy impose on society as a whole. Some of which are borne by the producers and consumers of the energy. However, other social costs have not been internalized in the costing structure of the various fuel cycle, and therefore have not been fully considered in the past. These costs are referred to as external costs. The aim of the ExternE project is the computation of these external costs using a common methodology and the design of a unified framework for the presentation of the results. For direct comparison to be made between energy options, it is necessary that a common approach is taken. Two important categories of physical impacts that potentially fall into the classification of external costs are human health effects and environmental impacts. This report presents a methodology for an assessment of the nuclear fuel cycle that could be applied anywhere in Europe, however in this report, whenever possible, site-specific information for France has been used. The first phase of this project was a joint European Community/U.S. Department of Energy effort and the final results for the priority pathways of the nuclear fuel cycle presented in this document have been compared to the preliminary results reported by the US team at Oak Ridge National Laboratory

  12. Nuclear fuel cycle: estimation of physical impacts and monetary valuation for priority pathways

    Energy Technology Data Exchange (ETDEWEB)

    Dreicer, M.; Tort, V.; Manen, P.

    1995-02-01

    The decision-making process for setting future energy policy requires a large range of information. An important component in this process is the comparison of the various costs incurred by the different types of energy systems. Among these costs are those that the production and consumption of energy impose on society as a whole. Some of which are borne by the producers and consumers of the energy. However, other social costs have not been internalized in the costing structure of the various fuel cycle, and therefore have not been fully considered in the past. These costs are referred to as external costs. The aim of the ExternE project is the computation of these external costs using a common methodology and the design of a unified framework for the presentation of the results. For direct comparison to be made between energy options, it is necessary that a common approach is taken. Two important categories of physical impacts that potentially fall into the classification of external costs are human health effects and environmental impacts. This report presents a methodology for an assessment of the nuclear fuel cycle that could be applied anywhere in Europe, however in this report, whenever possible, site-specific information for France has been used. The first phase of this project was a joint European Community/U.S. Department of Energy effort and the final results for the priority pathways of the nuclear fuel cycle presented in this document have been compared to the preliminary results reported by the US team at Oak Ridge National Laboratory.

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

    Directory of Open Access Journals (Sweden)

    Koramit Suppipat

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

  14. 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.

  15. Ouabain Enhances ADPKD Cell Apoptosis via the Intrinsic Pathway.

    Science.gov (United States)

    Venugopal, Jessica; Blanco, Gustavo

    2016-01-01

    Progression of autosomal dominant polycystic kidney disease (ADPKD) is highly influenced by factors circulating in blood. We have shown that the hormone ouabain enhances several characteristics of the ADPKD cystic phenotype, including the rate of cell proliferation, fluid secretion and the capacity of the cells to form cysts. In this work, we found that physiological levels of ouabain (3 nM) also promote programmed cell death of renal epithelial cells obtained from kidney cysts of patients with ADPKD (ADPKD cells). This was determined by Alexa Fluor 488 labeled-Annexin-V staining and TUNEL assay, both biochemical markers of apoptosis. Ouabain-induced apoptosis also takes place when ADPKD cell growth is blocked; suggesting that the effect is not secondary to the stimulatory actions of ouabain on cell proliferation. Ouabain alters the expression of BCL family of proteins, reducing BCL-2 and increasing BAX expression levels, anti- and pro-apoptotic mediators respectively. In addition, ouabain caused the release of cytochrome c from mitochondria. Moreover, ouabain activates caspase-3, a key "executioner" caspase in the cell apoptotic pathway, but did not affect caspase-8. This suggests that ouabain triggers ADPKD cell apoptosis by stimulating the intrinsic, but not the extrinsic pathway of programmed cell death. The apoptotic effects of ouabain are specific for ADPKD cells and do not occur in normal human kidney cells (NHK cells). Taken together with our previous observations, these results show that ouabain causes an imbalance in cell growth/death, to favor growth of the cystic cells. This event, characteristic of ADPKD, further suggests the importance of ouabain as a circulating factor that promotes ADPKD progression. PMID:27047392

  16. Ouabain enhances ADPKD cell apoptosis via the intrinsic pathway

    Directory of Open Access Journals (Sweden)

    Gustavo eBlanco

    2016-03-01

    Full Text Available Progression of autosomal dominant polycystic kidney disease (ADPKD is highly influenced by factors circulating in blood. We have shown that the hormone ouabain enhances several characteristics of the ADPKD cystic phenotype, including the rate of cell proliferation, fluid secretion and the capacity of the cells to form cysts. In this work, we found that physiological levels of ouabain (3nM also promote programmed cell death of renal epithelial cells obtained from kidney cysts of patients with ADPKD (ADPKD cells. This was determined by Alexa Fluor 488 labeled-Annexin-V staining and TUNEL assay, both biochemical markers of apoptosis. Ouabain-induced apoptosis also takes place when ADPKD cell growth is blocked; suggesting that the effect is not secondary to the stimulatory actions of ouabain on cell proliferation. Ouabain alters the expression of BCL family of proteins, reducing BCL-2 and increasing BAX expression levels, anti- and pro-apoptotic mediators respectively. In addition, ouabain caused the release of cytochrome c from mitochondria. Moreover, ouabain activates caspase-3, a key executioner caspase in the cell apoptotic pathway, but did not affect caspase-8. This suggests that ouabain triggers ADPKD cell apoptosis by stimulating the intrinsic, but not the extrinsic pathway of programmed cell death. The apoptotic effects of ouabain are specific for ADPKD cells and do not occur in normal human kidney cells (NHK cells. Taken together with our previous observations, these results show that ouabain causes an imbalance in cell growth/death, to favor growth of the cystic cells. This event, characteristic of ADPKD, further suggests the importance of ouabain as a circulating factor that promotes ADPKD progression.

  17. 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.

  18. 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

  19. Identification of a dTDP-rhamnose biosynthetic pathway that oscillates with the molting cycle in Caenorhabditis elegans.

    Science.gov (United States)

    Feng, Likui; Shou, Qingyao; Butcher, Rebecca A

    2016-06-01

    L-Rhamnose is a common component of cell-wall polysaccharides, glycoproteins and some natural products in bacteria and plants, but is rare in fungi and animals. In the present study, we identify and characterize a biosynthetic pathway for dTDP-rhamnose in Caenorhabditis elegans that is highly conserved across nematode species. We show that RML-1 activates glucose 1-phosphate (Glc-1-P) in the presence of either dTTP or UTP to yield dTDP-glucose or UDP-glucose, respectively. RML-2 is a dTDP-glucose 4,6-dehydratase, converting dTDP-glucose into dTDP-4-keto-6-deoxyglucose. Using mass spectrometry and NMR spectroscopy, we demonstrate that coincubation of dTDP-4-keto-6-deoxyglucose with RML-3 (3,5-epimerase) and RML-4 (4-keto-reductase) produces dTDP-rhamnose. RML-4 could only be expressed and purified in an active form through co-expression with a co-regulated protein, RML-5, which forms a complex with RML-4. Analysis of the sugar nucleotide pool in C. elegans established the presence of dTDP-rhamnose in vivo Targeting the expression of the rhamnose biosynthetic genes by RNAi resulted in significant reductions in dTDP-rhamnose, but had no effect on the biosynthesis of a closely related sugar, ascarylose, found in the ascaroside pheromones. Therefore, the rhamnose and ascarylose biosynthetic pathways are distinct. We also show that transcriptional reporters for the rhamnose biosynthetic genes are expressed highly in the embryo, in the hypodermis during molting cycles and in the hypodermal seam cells specifically before the molt to the stress-resistant dauer larval stage. These expression patterns suggest that rhamnose biosynthesis may play an important role in hypodermal development or the production of the cuticle or surface coat during molting. PMID:27009306

  20. 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...

  1. 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

  2. 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

  3. Market access pathways for cell therapies in France

    Science.gov (United States)

    Rémuzat, Cécile; Toumi, Mondher; Jørgensen, Jesper; Kefalas, Panos

    2015-01-01

    Introduction and objective Cell therapies can be classified into three main categories of products: advanced therapy medicinal products (ATMPs), ATMPs prepared on a non-routine basis (hospital exemptions), and minimally manipulated cells. Despite the benefits that cell therapies can bring to patients, they are subject to complex pathways to reach the market in France. The objective of this study was to identify and describe routes to market access for cell therapies in France and how these vary by regulatory status. Methodology The research was structured following five main steps: (1) identification of the French regulatory framework for cell therapies; (2) identification of the health products categorised as cell therapies in France; (3) mapping of the market access pathways per category of cell therapy; (4) validation of findings by interviewing experts; and (5) development of a roadmap summarising market access pathways for cell therapies in France. The secondary research methodology included a comprehensive literature review conducted on websites of French public health institutions, complemented by a research for peer-reviewed articles, abstracts, and grey literature. Results Different market access pathways are possible depending on the cell therapy category. For ATMPs, market access pathways depend on the licensing status of the therapy. Licensed ATMPs followed the same market access pathways as ‘conventional’ pharmaceuticals, whereas not-yet-licensed ATMPs can be funded via a specific financial allowance under the framework of a Temporary Authorisation for Use procedure or various research programmes. For new ATMPs that are associated with a separate medical device (not considered as ‘combined ATMPs’) or associated with a new medical procedure, additional pathways will apply for the medical device and/or medical procedure to be reimbursed in the ambulatory settings or at hospital. The most likely funding option for ATMPs prepared on a non

  4. 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.

  5. 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

  6. 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....

  7. 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.

  8. 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

  9. 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.

  10. The Retinoblastoma pathway regulates stem cell proliferation in freshwater planarians.

    Science.gov (United States)

    Zhu, Shu Jun; Pearson, Bret J

    2013-01-15

    Freshwater planarians are flatworms of the Lophotrochozoan superphylum and are well known for their regenerative abilities, which rely on a large population of pluripotent adult stem cells. However, the mechanisms by which planarians maintain a precise population of adult stem cells while balancing proliferation and cell death, remain to be elucidated. Here we have identified, characterized, and functionally tested the core Retinoblastoma (Rb) pathway components in planarian adult stem cell biology. The Rb pathway is an ancient and conserved mechanism of proliferation control from plants to animals and is composed of three core components: an Rb protein, and a transcription factor heterodimer of E2F and DP proteins. Although the planarian genome contains all components of the Rb pathway, we found that they have undergone gene loss from the ancestral state, similar to other species in their phylum. The single Rb homolog (Smed-Rb) was highly expressed in planarian stem cells and was required for stem cell maintenance, similar to the Rb-homologs p107 and p130 in vertebrates. We show that planarians and their phylum have undergone the most severe reduction in E2F genes observed thus far, and the single remaining E2F was predicted to be a repressive-type E2F (Smed-E2F4-1). Knockdown of either Smed-E2F4-1 or its dimerization partner Dp (Smed-Dp) by RNAi resulted in temporary hyper-proliferation. Finally, we showed that known Rb-interacting genes in other systems, histone deacetylase 1 and cyclinD (Smed-HDAC1; Smed-cycD), were similar to Rb in expression and phenotypes when knocked down by RNAi, suggesting that these established interactions with Rb may also be conserved in planarians. Together, these results showed that planarians use the conserved components of the Rb tumor suppressor pathway to control proliferation and cell survival. PMID:23123964

  11. Hedgehog Pathway Inhibition Radiosensitizes Non-Small Cell Lung Cancers

    Energy Technology Data Exchange (ETDEWEB)

    Zeng, Jing; Aziz, Khaled; Chettiar, Sivarajan T. [Department of Radiation Oncology and Molecular Radiation Sciences, The Johns Hopkins University School of Medicine, Baltimore, Maryland (United States); Aftab, Blake T. [Department of Medical Oncology, The Johns Hopkins University School of Medicine, Baltimore, Maryland (United States); Armour, Michael; Gajula, Rajendra; Gandhi, Nishant; Salih, Tarek; Herman, Joseph M.; Wong, John [Department of Radiation Oncology and Molecular Radiation Sciences, The Johns Hopkins University School of Medicine, Baltimore, Maryland (United States); Rudin, Charles M. [Department of Medical Oncology, The Johns Hopkins University School of Medicine, Baltimore, Maryland (United States); Tran, Phuoc T. [Department of Radiation Oncology and Molecular Radiation Sciences, The Johns Hopkins University School of Medicine, Baltimore, Maryland (United States); Department of Medical Oncology, The Johns Hopkins University School of Medicine, Baltimore, Maryland (United States); Hales, Russell K., E-mail: rhales1@jhmi.edu [Department of Radiation Oncology and Molecular Radiation Sciences, The Johns Hopkins University School of Medicine, Baltimore, Maryland (United States)

    2013-05-01

    Purpose: Despite improvements in chemoradiation, local control remains a major clinical problem in locally advanced non-small cell lung cancer. The Hedgehog pathway has been implicated in tumor recurrence by promoting survival of tumorigenic precursors and through effects on tumor-associated stroma. Whether Hedgehog inhibition can affect radiation efficacy in vivo has not been reported. Methods and Materials: We evaluated the effects of a targeted Hedgehog inhibitor (HhAntag) and radiation on clonogenic survival of human non-small cell lung cancer lines in vitro. Using an A549 cell line xenograft model, we examined tumor growth, proliferation, apoptosis, and gene expression changes after concomitant HhAntag and radiation. In a transgenic mouse model of Kras{sup G12D}-induced and Twist1-induced lung adenocarcinoma, we assessed tumor response to radiation and HhAntag by serial micro-computed tomography (CT) scanning. Results: In 4 human lung cancer lines in vitro, HhAntag showed little or no effect on radiosensitivity. By contrast, in both the human tumor xenograft and murine inducible transgenic models, HhAntag enhanced radiation efficacy and delayed tumor growth. By use of the human xenograft model to differentiate tumor and stromal effects, mouse stromal cells, but not human tumor cells, showed significant and consistent downregulation of Hedgehog pathway gene expression. This was associated with increased tumor cell apoptosis. Conclusions: Targeted Hedgehog pathway inhibition can increase in vivo radiation efficacy in lung cancer preclinical models. This effect is associated with pathway suppression in tumor-associated stroma. These data support clinical testing of Hedgehog inhibitors as a component of multimodality therapy for locally advanced non-small cell lung cancer.

  12. Multiple Defects of Cell Cycle Checkpoints in U937-ASPI3K, an U937 Cell Mutant Stably Expressing Anti-Sense ATM Gene cDNA

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    (Ataxia-telangiectasia mutated gene (ATM) functions in control of cell cycle checkpoints in responding to DNA damage and protects cells from undergoing apoptosis. Knock-out within tumor cells of endogenous ATM will achieve therapeutic benefits and nable a better understanding of the decisive mechanisms of cell death or survival in response to DNA damaging agents. ) In present paper, we sought to characterize the cell cycle checkpoint profiles in U937-ASPI3K, a U937 cell mutant that was previously established with endogenous ATM knock-out phenotype. Synchronized U937-ASPI3K was exposed to 137Cs irradiation, G1, S, G2/M cell cycle checkpoint profiles were evaluated by determining cell cycle kinetics, p53/p21 protein, cyclin dependent kinase 2 (CDK2) and p34CDC2 kinase activity in response to irradiation. U937-ASPI3K exhibited multiple defects in cell cycle checkpoints as defined by failing to arrest cells upon irradiation. The accumulation of cellular p53/p21 protein and inhibition of CDK kinase was also abolished in U937-ASPI3K. It was concluded that the stable expression of anti-sense PI3K cDNA fragment completely abolished multiple cell cycle checkpoints in U937-ASPI3K, and hence U937-ASPI3K with an AT-like phenotype could serves as a valuable model system for investigating the signal transduction pathway in responding to DNA damaging-based cancer therapy.

  13. 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

  14. 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.

  15. 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...

  16. Expression of cell cycle regulating factor mRNA in small cell lung cancer xenografts

    DEFF Research Database (Denmark)

    Krarup, M; Poulsen, H S; Spang-Thomsen, M

    1998-01-01

    CDK6 when in vitro and in vivo data were compared. Two of the cell lines that express the retinoblastoma (Rb) protein had no sign of a deregulated Rb pathway but further studies at the protein level are necessary to demonstrate whether these two cell lines should have a normal Rb pathway or whether...

  17. 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.

  18. 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...

  19. Divergence to apoptosis from ROS induced cell cycle arrest: Effect of cadmium

    Energy Technology Data Exchange (ETDEWEB)

    Chatterjee, Soumya; Kundu, Subhadip; Sengupta, Suman [Department of Environmental Science, University of Kalyani, West Bengal 741235 (India); Department of Zoology, University of Calcutta, Calcutta-700019, West Bengal (India); Bhattacharyya, Arindam, E-mail: arindam19@yahoo.com [Department of Environmental Science, University of Kalyani, West Bengal 741235 (India); Department of Zoology, University of Calcutta, Calcutta-700019, West Bengal (India)

    2009-04-26

    Recently, the role of cadmium (Cd) in immunosupression has gained importance. Nevertheless, the signaling pathways underlying cadmium-induced immune cell death remains largely unclear. In accordance to our previous in vivo report, and to evaluate the further details of the mechanism, we have investigated the effects of cadmium (CdCl{sub 2}, H{sub 2}O) on cell cycle regulation and apoptosis in splenocytes in vitro. Our results have revealed that reactive oxygen species (ROS) and p21 are involved in cell cycle arrest in a p53 independent manner but late hour apoptotic response was accompanied by the p53 up-regulation, loss of mitochondrial transmembrane potential (MTP), down-regulation of Bcl-xl, activation of caspase-3 and release of cytochrome c (Cyt c). However, pifithrin alfa (PFT-{alpha}), an inhibitor of p53, fails to rescue the cells from the cadmium-induced cell cycle arrest but prevents Bcl-xl down-regulation and loss of {Delta}{psi}{sub m}, which indicates that there is an involvement of p53 in apoptosis. In contrast, treatment with N-acetyl cysteine (NAC) can prevent cell cycle arrest and p21 up-regulation at early hours. Although it is clear that, NAC has no effect on apoptosis, p53 expression and MPT changes at late stage events. Taken together, we have demonstrated that cadmium promotes ROS generation, which potently initiates the cell cycle arrest at early hours and finally induces p53-dependent apoptosis at later part of the event.

  20. 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.

  1. Methoxychlor inhibits growth of antral follicles by altering cell cycle regulators

    International Nuclear Information System (INIS)

    Methoxychlor (MXC) reduces fertility in female rodents, decreases antral follicle numbers, and increases atresia through oxidative stress pathways. MXC also inhibits antral follicle growth in vitro. The mechanism by which MXC inhibits growth of follicles is unknown. The growth of follicles is controlled, in part, by cell cycle regulators. Thus, we tested the hypothesis that MXC inhibits follicle growth by reducing the levels of selected cell cycle regulators. Further, we tested whether co-treatment with an antioxidant, N-acetyl cysteine (NAC), prevents the MXC-induced reduction in cell cycle regulators. For in vivo studies, adult cycling CD-1 mice were dosed with MXC or vehicle for 20 days. Treated ovaries were subjected to immunohistochemistry for proliferating cell nuclear antigen (PCNA) staining. For in vitro studies, antral follicles isolated from adult cycling CD-1 mouse ovaries were cultured with vehicle, MXC, and/or NAC for 48, 72 and 96 h. Levels of cyclin D2 (Ccnd2) and cyclin dependent kinase 4 (Cdk4) were measured using in vivo and in vitro samples. The results indicate that MXC decreased PCNA staining, and Ccnd2 and Cdk4 levels compared to controls. NAC co-treatment restored follicle growth and expression of Ccnd2 and Cdk4. Collectively, these data indicate that MXC exposure reduces the levels of Ccnd2 and Cdk4 in follicles, and that protection from oxidative stress restores Ccnd2 and Cdk4 levels. Therefore, MXC-induced oxidative stress may decrease the levels of cell cycle regulators, which in turn, results in inhibition of the growth of antral follicles.

  2. 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....

  3. 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

  4. Alanine and aspartate aminotransferase and glutamine-cycling pathway: Their roles in pathogenesis of metabolic syndrome

    Institute of Scientific and Technical Information of China (English)

    Silvia Sookoian; Carlos J Pirola

    2012-01-01

    Although new research technologies are constantly used to look either for genes or biomarkers in the prediction of metabolic syndrome (MS),the pathogenesis and pathophysiology of this complex disease remains a major challenge.Interestingly,Cheng et al recently investigated possible pathways underlying MS by high-throughput metabolite profiling in two large and well characterized community-based cohorts.The authors explored by liquid chromatography and mass spectrometry the plasma concentrations of 45distinct metabolites and examined their relation to cardiometabolic risk,and observed that metabolic risk factors such as obesity,insulin resistance (IR),high blood pressure,and dyslipidemia were associated with several metabolites,including branched-chain amino acids,other hydrophobic amino acids,tryptophan breakdown products,and nucleotide metabolites.In addition,the authors found a significant association of IR traits with glutamine,glutamate and the glutamineto-glutamate ratio.These data provide new insight into the pathogenesis of MS-associated phenotypes and introduce a crucial role of glutamine-cycling pathway as prominently involved in the development of metabolic risk.We consider that the hypothesis about the role of abnormal glutamate metabolism in the pathogenesis of the MS is certainly challenging and suggests the critical role of the liver in the global metabolic modulation as glutamate metabolism is linked with aminotransferase reactions.We discuss here the critical role of the "liver metabolism" in the pathogenesis of the MS and IR,and postulate that before fatty liver develops,abnormal levels of liver enzymes,such as alanine and aspartate aminotransferases might reflect high levels of hepatic transamination of amino acids in the liver.

  5. Role of AKT/mTORC1 pathway in pancreatic β-cell proliferation.

    Directory of Open Access Journals (Sweden)

    Balcazar Morales, Norman

    2012-09-01

    Full Text Available Growth factors, insulin signaling and nutrients are important regulators of β-cell mass and function. The events linking these signals to regulation of β-cell mass are not completely understood. Recent findings indicate that mTOR pathway integrates signals from growth factors and nutrients with transcription, translation, cell size, cytoskeleton remodeling and mitochondrial metabolism. mTOR is a part of two distinct complexes; mTORC1 and mTORC2. The mammalian TORC1 is sensitive to rapamycin and contains Raptor, deptor, PRAS40 and the G protein β-subunit-like protein (GβL. mTORC1 activates key regulators of protein translation; ribosomal S6 kinase (S6K and eukaryote initiation factor 4E-binding protein 1.This review summarizes current findings about the role of AKT/mTORC1 signaling in regulation of pancreatic β cell mass and proliferation. mTORC1 is a major regulator of β-cell cycle progression by modulation of cyclins D2, D3 and cdk4/cyclin D activity. These studies uncovered key novel pathways controlling cell cycle progression in β-cells in vivo. This information can be used to develop alternative approaches to expand β-cell mass in vivo and in vitro without the risk of oncogenic transformation. The acquisition of such knowledge is critical for the design of improved therapeutic strategies for the treatment and cure of diabetes as well as to understand the effects of mTOR inhibitors in β-cell function.

  6. 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)

  7. Novel Hedgehog pathway targets against basal cell carcinoma

    International Nuclear Information System (INIS)

    The Hedgehog signaling pathway plays a key role in directing growth and patterning during embryonic development and is required in vertebrates for the normal development of many structures, including the neural tube, axial skeleton, skin, and hair. Aberrant activation of the Hedgehog (Hh) pathway in adult tissue is associated with the development of basal cell carcinoma (BCC), medulloblastoma, and a subset of pancreatic, gastrointestinal, and other cancers. This review will provide an overview of what is known about the mechanisms by which activation of Hedgehog signaling leads to the development of BCCs and will review two recent papers suggesting that agents that modulate sterol levels might influence the Hh pathway. Thus, sterols may be a new therapeutic target for the treatment of BCCs, and readily available agents such as statins (HMG-CoA reductase inhibitors) or vitamin D might be helpful in reducing BCC incidence

  8. Limitations of toxicity characterization in life cycle assessment: Can adverse outcome pathways provide a new foundation?

    Science.gov (United States)

    Gust, Kurt A; Collier, Zachary A; Mayo, Michael L; Stanley, Jacob K; Gong, Ping; Chappell, Mark A

    2016-07-01

    Life cycle assessment (LCA) has considerable merit for holistic evaluation of product planning, development, production, and disposal, with the inherent benefit of providing a forecast of potential health and environmental impacts. However, a technical review of current life cycle impact assessment (LCIA) methods revealed limitations within the biological effects assessment protocols, including: simplistic assessment approaches and models; an inability to integrate emerging types of toxicity data; a reliance on linear impact assessment models; a lack of methods to mitigate uncertainty; and no explicit consideration of effects in species of concern. The purpose of the current study is to demonstrate that a new concept in toxicological and regulatory assessment, the adverse outcome pathway (AOP), has many useful attributes of potential use to ameliorate many of these problems, to expand data utility and model robustness, and to enable more accurate and defensible biological effects assessments within LCIA. Background, context, and examples have been provided to demonstrate these potential benefits. We additionally propose that these benefits can be most effectively realized through development of quantitative AOPs (qAOPs) crafted to meet the needs of the LCIA framework. As a means to stimulate qAOP research and development in support of LCIA, we propose 3 conceptual classes of qAOP, each with unique inherent attributes for supporting LCIA: 1) mechanistic, including computational toxicology models; 2) probabilistic, including Bayesian networks and supervised machine learning models; and 3) weight of evidence, including models built using decision-analytic methods. Overall, we have highlighted a number of potential applications of qAOPs that can refine and add value to LCIA. As the AOP concept and support framework matures, we see the potential for qAOPs to serve a foundational role for next-generation effects characterization within LCIA. Integr Environ Assess Manag

  9. Lithium inhibits tumorigenic potential of PDA cells through targeting hedgehog-GLI signaling pathway.

    Directory of Open Access Journals (Sweden)

    Zhonglu Peng

    Full Text Available Hedgehog signaling pathway plays a critical role in the initiation and development of pancreatic ductal adenocarcinoma (PDA and represents an attractive target for PDA treatment. Lithium, a clinical mood stabilizer for mental disorders, potently inhibits the activity of glycogen synthase kinase 3β (GSK3β that promotes the ubiquitin-dependent proteasome degradation of GLI1, an important downstream component of hedgehog signaling. Herein, we report that lithium inhibits cell proliferation, blocks G1/S cell-cycle progression, induces cell apoptosis and suppresses tumorigenic potential of PDA cells through down-regulation of the expression and activity of GLI1. Moreover, lithium synergistically enhances the anti-cancer effect of gemcitabine. These findings further our knowledge of mechanisms of action for lithium and provide a potentially new therapeutic strategy for PDA through targeting GLI1.

  10. A Possible Anticancer Agent, Type III Interferon, Activates Cell Death Pathways and Produces Antitumor Effects

    Directory of Open Access Journals (Sweden)

    Masatoshi Tagawa

    2011-01-01

    Full Text Available Recently identified interleukin-28 and -29 belong to a novel type III interferon (IFN family, which could have distinct biological properties from type I and II IFNs. Type I IFNs, IFN-α/β, have been clinically applied for treating a certain kind of malignancies for over 30 years, but a wide range of the adverse effects hampered the further clinical applications. Type III IFNs, IFN-λs, have similar signaling pathways as IFN-α/β and inhibits proliferation of tumor cells through cell cycle arrest or apoptosis. Restricted patterns of type III IFN receptor expression in contrast to ubiquitously expressed IFN-α/β receptors suggest that type III IFNs have limited cytotoxicity to normal cells and can be a possible anticancer agent. In this paper, we summarize the current knowledge on the IFN-λs-mediated tumor cell death and discuss the functional difference between type I and III IFNs.

  11. SITS-sensitive Cl- conductance pathway in chick intestinal cells

    International Nuclear Information System (INIS)

    The unidirectional influx of 36Cl- into isolated chick epithelial cells is 30% inhibited by 300 μM SITS. Characteristics of the SITS-sensitive flux pathway were examined in terms of sensitivity to changes in membrane potential and intracellular pH. Potential dependence was evaluated using unidirectional influx of [14C]tetraphenylphosphonium ([14C]-TPP+) as a qualitative sensor of diffusion potentials created by experimentally imposed gradients of CL-. Steady-state distribution of [14C]methylamine ([14C]MA) was used to examine for Cl--dependent changes in intracellular pH. Imposed Na+ gradients, but not Cl- gradients, induce changes in [14C]MA distribution. SITS does not alter the [14C]MA distribution observed in cells with imposed gradients of Na+ and Cl-. Both results suggest that inhibition of Cl- influx. However, if relative permeabilities for ion pairs via conductance pathways are compared, it can be shown that SITS causes a marked reduction of PCl relative to either PNa or PK. SITS also inhibits electrically induced influx of [14C]TPP+ or [14C]α-methylglucoside driven by imposed Cl- influx can be blocked by SITS. These observations are all consistent with a SITS-sensitive Cl- conductance pathway associated with the plasma membrane of chick intestinal cells. No Cl--OH- exchange capability can be detected for chick intestinal cells

  12. 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.

  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. 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

  15. 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...

  16. Aristolochic acid-induced apoptosis and G2 cell cycle arrest depends on ROS generation and MAP kinases activation.

    Science.gov (United States)

    Romanov, Victor; Whyard, Terry C; Waltzer, Wayne C; Grollman, Arthur P; Rosenquist, Thomas

    2015-01-01

    Ingestion of aristolochic acids (AAs) contained in herbal remedies results in a renal disease and, frequently, urothelial malignancy. The genotoxicity of AA in renal cells, including mutagenic DNA adducts formation, is well documented. However, the mechanisms of AA-induced tubular atrophy and renal fibrosis are largely unknown. To better elucidate some aspects of this process, we studied cell cycle distribution and cell survival of renal epithelial cells treated with AAI at low and high doses. A low dose of AA induces cell cycle arrest in G2/M phase via activation of DNA damage checkpoint pathway ATM-Chk2-p53-p21. DNA damage signaling pathway is activated more likely via increased production of reactive oxygen species (ROS) caused by AA treatment then via DNA damage induced directly by AA. Higher AA concentration induced cell death partly via apoptosis. Since mitogen-activated protein kinases play an important role in cell survival, death and cell cycle progression, we assayed their function in AA-treated renal tubular epithelial cells. ERK1/2 and p38 but not JNK were activated in cells treated with AA. In addition, pharmacological inhibition of ERK1/2 and p38 as well as suppression of ROS generation with N-acetyl-L-cysteine resulted in the partial relief of cells from G2/M checkpoint and a decline of apoptosis level. Cell cycle arrest may be a mechanism for DNA repair, cell survival and reprogramming of epithelial cells to the fibroblast type. An apoptosis of renal epithelial cells at higher AA dose might be necessary to provide space for newly reprogrammed fibrotic cells. PMID:24792323

  17. 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

  18. 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...

  19. 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...

  20. Repression of germline RNAi pathways in somatic cells by retinoblastoma pathway chromatin complexes.

    Directory of Open Access Journals (Sweden)

    Xiaoyun Wu

    Full Text Available The retinoblastoma (Rb tumor suppressor acts with a number of chromatin cofactors in a wide range of species to suppress cell proliferation. The Caenorhabditis elegans retinoblastoma gene and many of these cofactors, called synMuv B genes, were identified in genetic screens for cell lineage defects caused by growth factor misexpression. Mutations in many synMuv B genes, including lin-35/Rb, also cause somatic misexpression of the germline RNA processing P granules and enhanced RNAi. We show here that multiple small RNA components, including a set of germline-specific Argonaute genes, are misexpressed in the soma of many synMuv B mutant animals, revealing one node for enhanced RNAi. Distinct classes of synMuv B mutants differ in the subcellular architecture of their misexpressed P granules, their profile of misexpressed small RNA and P granule genes, as well as their enhancement of RNAi and the related silencing of transgenes. These differences define three classes of synMuv B genes, representing three chromatin complexes: a LIN-35/Rb-containing DRM core complex, a SUMO-recruited Mec complex, and a synMuv B heterochromatin complex, suggesting that intersecting chromatin pathways regulate the repression of small RNA and P granule genes in the soma and the potency of RNAi. Consistent with this, the DRM complex and the synMuv B heterochromatin complex were genetically additive and displayed distinct antagonistic interactions with the MES-4 histone methyltransferase and the MRG-1 chromodomain protein, two germline chromatin regulators required for the synMuv phenotype and the somatic misexpression of P granule components. Thus intersecting synMuv B chromatin pathways conspire with synMuv B suppressor chromatin factors to regulate the expression of small RNA pathway genes, which enables heightened RNAi response. Regulation of small RNA pathway genes by human retinoblastoma may also underlie its role as a tumor suppressor gene.

  1. Repression of germline RNAi pathways in somatic cells by retinoblastoma pathway chromatin complexes.

    Science.gov (United States)

    Wu, Xiaoyun; Shi, Zhen; Cui, Mingxue; Han, Min; Ruvkun, Gary

    2012-01-01

    The retinoblastoma (Rb) tumor suppressor acts with a number of chromatin cofactors in a wide range of species to suppress cell proliferation. The Caenorhabditis elegans retinoblastoma gene and many of these cofactors, called synMuv B genes, were identified in genetic screens for cell lineage defects caused by growth factor misexpression. Mutations in many synMuv B genes, including lin-35/Rb, also cause somatic misexpression of the germline RNA processing P granules and enhanced RNAi. We show here that multiple small RNA components, including a set of germline-specific Argonaute genes, are misexpressed in the soma of many synMuv B mutant animals, revealing one node for enhanced RNAi. Distinct classes of synMuv B mutants differ in the subcellular architecture of their misexpressed P granules, their profile of misexpressed small RNA and P granule genes, as well as their enhancement of RNAi and the related silencing of transgenes. These differences define three classes of synMuv B genes, representing three chromatin complexes: a LIN-35/Rb-containing DRM core complex, a SUMO-recruited Mec complex, and a synMuv B heterochromatin complex, suggesting that intersecting chromatin pathways regulate the repression of small RNA and P granule genes in the soma and the potency of RNAi. Consistent with this, the DRM complex and the synMuv B heterochromatin complex were genetically additive and displayed distinct antagonistic interactions with the MES-4 histone methyltransferase and the MRG-1 chromodomain protein, two germline chromatin regulators required for the synMuv phenotype and the somatic misexpression of P granule components. Thus intersecting synMuv B chromatin pathways conspire with synMuv B suppressor chromatin factors to regulate the expression of small RNA pathway genes, which enables heightened RNAi response. Regulation of small RNA pathway genes by human retinoblastoma may also underlie its role as a tumor suppressor gene. PMID:22412383

  2. Uropathogenic Escherichia coli Epigenetically Manipulate Host Cell Death Pathways.

    Science.gov (United States)

    Zhang, Zhengguo; Wang, Ming; Eisel, Florian; Tchatalbachev, Svetlin; Chakraborty, Trinad; Meinhardt, Andreas; Bhushan, Sudhanshu

    2016-04-01

    Urinary tract infections caused by uropathogenic Escherichia coli (UPEC) pathovars belong to the most frequent infections in human. It is well established that UPEC can subvert innate immune responses, but the role of UPEC in interfering with host cell death pathways is not known. Here, we show that UPEC abrogates activation of the host cell prosurvival protein kinase B signaling pathway, which results in the activation of mammalian forkhead box O (FOXO) transcription factors. Although FOXOs were localized in the nucleus and showed increased DNA-binding activity, no change in the expression levels of FOXO target genes were observed. UPEC can suppress BIM expression induced by LY249002, which results in attenuation of caspase 3 activation and blockage of apoptosis. Mechanistically, BIM expression appears to be epigenetically silenced by a decrease in histone 4 acetylation at the BIM promoter site. Taken together, these results suggest that UPEC can epigenetically silence BIM expression, a molecular switch that prevents apoptosis. PMID:26621912

  3. 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...

  4. 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...

  5. RNA interference regulates the cell cycle checkpoint through the RNA export factor, Ptr1, in fission yeast

    Energy Technology Data Exchange (ETDEWEB)

    Iida, Tetsushi, E-mail: tiida@nig.ac.jp [Division of Cytogenetics, National Institute of Genetics, Mishima, 1111 Yata, Mishima 411-8540 (Japan); The Graduate University for Advanced Studies, Sokendai, Mishima, 1111 Yata, Mishima 411-8540 (Japan); Precursory Research for Embryonic Science and Technology (PRESTO), Japan Science and Technology Agency (JST), 4-1-8, Honcho, Kawaguchi-shi, Saitama 332-0012 (Japan); Iida, Naoko [Division of Mutagenesis, National Institute of Genetics, Mishima, 1111 Yata, Mishima 411-8540 (Japan); Tsutsui, Yasuhiro [Department of Life Science, Graduate School of Bioscience and Biotechnology, Tokyo Institute of Technology, Nagatsuda-cho, Midori-ku, Yokohama 226-8501 (Japan); Yamao, Fumiaki [Division of Mutagenesis, National Institute of Genetics, Mishima, 1111 Yata, Mishima 411-8540 (Japan); The Graduate University for Advanced Studies, Sokendai, Mishima, 1111 Yata, Mishima 411-8540 (Japan); Kobayashi, Takehiko [Division of Cytogenetics, National Institute of Genetics, Mishima, 1111 Yata, Mishima 411-8540 (Japan); The Graduate University for Advanced Studies, Sokendai, Mishima, 1111 Yata, Mishima 411-8540 (Japan)

    2012-10-12

    Highlights: Black-Right-Pointing-Pointer RNAi is linked to the cell cycle checkpoint in fission yeast. Black-Right-Pointing-Pointer Ptr1 co-purifies with Ago1. Black-Right-Pointing-Pointer The ptr1-1 mutation impairs the checkpoint but does not affect gene silencing. Black-Right-Pointing-Pointer ago1{sup +} and ptr1{sup +} regulate the cell cycle checkpoint via the same pathway. Black-Right-Pointing-Pointer Mutations in ago1{sup +} and ptr1{sup +} lead to the nuclear accumulation of poly(A){sup +} RNAs. -- Abstract: Ago1, an effector protein of RNA interference (RNAi), regulates heterochromatin silencing and cell cycle arrest in fission yeast. However, the mechanism by which Ago1 controls cell cycle checkpoint following hydroxyurea (HU) treatment has not been elucidated. In this study, we show that Ago1 and other RNAi factors control cell cycle checkpoint following HU treatment via a mechanism independent of silencing. While silencing requires dcr1{sup +}, the overexpression of ago1{sup +} alleviated the cell cycle defect in dcr1{Delta}. Ago1 interacted with the mRNA export factor, Ptr1. The ptr1-1 mutation impaired cell cycle checkpoint but gene silencing was unaffected. Genetic analysis revealed that the regulation of cell cycle checkpoint by ago1{sup +} is dependent on ptr1{sup +}. Nuclear accumulation of poly(A){sup +} RNAs was detected in mutants of ago1{sup +} and ptr1{sup +}, suggesting there is a functional link between the cell cycle checkpoint and RNAi-mediated RNA quality control.

  6. Protein synthesis and the cell cycle: centrosome reproduction in sea urchin eggs is not under translational control

    OpenAIRE

    1990-01-01

    The reproduction, or duplication, of the centrosome is an important event in a cell's preparation for mitosis. We sought to determine if centrosome reproduction is regulated by the synthesis and accumulation of cyclin proteins and/or the synthesis of centrosome-specific proteins at each cell cycle. We continuously treat sea urchin eggs, starting before fertilization, with a combination of emetine and anisomycin, drugs that have separate targets in the protein synthetic pathway. These drugs in...

  7. Nitrosative stress and redox-cycling agents synergize to cause mitochondrial dysfunction and cell death in endothelial cells

    Directory of Open Access Journals (Sweden)

    Anne R. Diers

    2013-01-01

    Full Text Available Nitric oxide production by the endothelium is required for normal vascular homeostasis; however, in conditions of oxidative stress, interactions of nitric oxide with reactive oxygen species (ROS are thought to underlie endothelial dysfunction. Beyond canonical nitric oxide signaling pathways, nitric oxide production results in the post-translational modification of protein thiols, termed S-nitrosation. The potential interplay between S-nitrosation and ROS remains poorly understood and is the focus of the current study. The effects of the S-nitrosating agent S-nitrosocysteine (CysNO in combination with redox-cycling agents was examined in bovine aortic endothelial cells (BAEC. CysNO significantly impairs mitochondrial function and depletes the NADH/NAD+ pool; however, these changes do not result in cell death. When faced with the additional stressor of a redox-cycling agent used to generate ROS, further loss of NAD+ occurs, and cellular ATP pools are depleted. Cellular S-nitrosothiols also accumulate, and cell death is triggered. These data demonstrate that CysNO sensitizes endothelial cells to redox-cycling agent-dependent mitochondrial dysfunction and cell death and identify attenuated degradation of S-nitrosothiols as one potential mechanism for the enhanced cytotoxicity.

  8. 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

  9. 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.

  10. 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.

  11. 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

  12. A natural compound, methyl angolensate, induces mitochondrial pathway of apoptosis in Daudi cells.

    Science.gov (United States)

    Chiruvella, Kishore K; Raghavan, Sathees C

    2011-08-01

    Natural products discovered from medicinal plants have played an important role in the treatment of cancer. In an effort to identify novel small molecules which can affect the proliferation of lymphoma cells, we tested methyl angolensate (MA), a plant derived tetranortriterpenoid, purified from the crude extract of the root callus of Soymida febrifuga commonly known as Indian red wood tree. We have tested MA for its cytotoxic properties on Burkitt's lymphoma cell lines, using various cellular assays. We observed that MA induces cytotoxicity in Daudi cells in a dose-dependent manner using trypan blue, MTT and LDH assays. We find that the treatment with MA led to activation of DNA double-strand break repair proteins including KU70 and KU80, suggesting the activation of nonhomologous DNA end joining pathway in surviving cells. Further, we find that methyl angolensate could induce apoptosis by cell cycle analysis, annexin V-FITC staining, DNA fragmentation and PARP cleavage. Besides, MA treatment led to reactive oxygen species generation and loss of mitochondrial transmembrane potential. These results suggest the activation of mitochondrial pathway of apoptosis. Hence, we identify MA as a potential chemotherapeutic agent against Daudi cells. PMID:20169399

  13. Blue Light Induces a Distinct Starch Degradation Pathway in Guard Cells for Stomatal Opening.

    Science.gov (United States)

    Horrer, Daniel; Flütsch, Sabrina; Pazmino, Diana; Matthews, Jack S A; Thalmann, Matthias; Nigro, Arianna; Leonhardt, Nathalie; Lawson, Tracy; Santelia, Diana

    2016-02-01

    Stomatal pores form a crucial interface between the leaf mesophyll and the atmosphere, controlling water and carbon balance in plants [1]. Major advances have been made in understanding the regulatory networks and ion fluxes in the guard cells surrounding the stomatal pore [2]. However, our knowledge on the role of carbon metabolism in these cells is still fragmentary [3-5]. In particular, the contribution of starch in stomatal opening remains elusive [6]. Here, we used Arabidopsis thaliana as a model plant to provide the first quantitative analysis of starch turnover in guard cells of intact leaves during the diurnal cycle. Starch is present in guard cells at the end of night, unlike in the rest of the leaf, but is rapidly degraded within 30 min of light. This process is critical for the rapidity of stomatal opening and biomass production. We exploited Arabidopsis molecular genetics to define the mechanism and regulation of guard cell starch metabolism, showing it to be mediated by a previously uncharacterized pathway. This involves the synergistic action of β-amylase 1 (BAM1) and α-amylase 3 (AMY3)-enzymes that are normally not required for nighttime starch degradation in other leaf tissues. This pathway is under the control of the phototropin-dependent blue-light signaling cascade and correlated with the activity of the plasma membrane H(+)-ATPase. Our results show that guard cell starch degradation has an important role in plant growth by driving stomatal responses to light. PMID:26774787

  14. 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...

  15. Tinospora cordifolia Induces Differentiation and Senescence Pathways in Neuroblastoma Cells.

    Science.gov (United States)

    Mishra, Rachana; Kaur, Gurcharan

    2015-08-01

    Children diagnosed with neuroblastomas often suffer from severe side as well as late effects of conventional treatments like chemotherapy and radiotherapy. Recent advances in understanding of molecular pathways involved in cellular differentiation and apoptosis have helped in the development of new therapeutic approach based on differentiation-based therapy of malignant tumours. Natural medicines with their holistic therapeutic approach are known to selectively eliminate cancer cells thus provide a better substitute for the conventional treatment modes. The current study was aimed to investigate the anti-cancer potential of aqueous ethanolic extract of Tinospora cordifolia (TCE) using IMR-32 human neuroblastoma cell line as a model system. TCE is highly recommended in Ayurveda for its general body and metal health-promoting properties. TCE treatment was seen to arrest the majority of cells in G0/G1 phase and modulated the expression of DNA clamp sliding protein (PCNA) and cyclin D1. Further, TCE-treated cells showed differentiation as revealed by their morphology and the expression of neuronal cell specific differentiation markers NF200, MAP-2 and NeuN in neuroblastoma cells. The differentiated phenotype was associated with induction of senescence and pro-apoptosis pathways by enhancing expression of senescence marker mortalin and Rel A subunit of nuclear factor kappa beta (NFkB) along with decreased expression of anti-apoptotic marker, Bcl-xl. TCE exhibited anti-metastatic activity and significantly reduced cell migration in the scratched area along with downregulation of neural cell adhesion molecule (NCAM) polysialylation and secretion of matrix metalloproteinases (MMPs). Our data suggest that crude extract or active phytochemicals from this plant may be a potential candidate for differentiation-based therapy of malignant neuroblastoma cells. PMID:25280667

  16. Blocking the NOTCH pathway can inhibit the growth of CD133-positive A549 cells and sensitize to chemotherapy

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Juntao; Mao, Zhangfan; Huang, Jie; Xie, Songping; Liu, Tianshu; Mao, Zhifu, E-mail: 48151660@qq.com

    2014-02-21

    Highlights: • Notch signaling pathway members are expressed lower levels in CD133+ cells. • CD133+ cells are not as sensitive as CD133− cells to chemotherapy. • GSI could inhibit the growth of both CD133+ and CD133− cells. • Blockade of Notch signaling pathway enhanced the effect of chemotherapy with CDDP. • DAPT/CDDP co-therapy caused G2/M arrest and elimination in CD133+ cells. - Abstract: Cancer stem cells (CSCs) are believed to play an important role in tumor growth and recurrence. These cells exhibit self-renewal and proliferation properties. CSCs also exhibit significant drug resistance compared with normal tumor cells. Finding new treatments that target CSCs could significantly enhance the effect of chemotherapy and improve patient survival. Notch signaling is known to regulate the development of the lungs by controlling the cell-fate determination of normal stem cells. In this study, we isolated CSCs from the human lung adenocarcinoma cell line A549. CD133 was used as a stem cell marker for fluorescence-activated cell sorting (FACS). We compared the expression of Notch signaling in both CD133+ and CD133− cells and blocked Notch signaling using the γ-secretase inhibitor DAPT (GSI-IX). The effect of combining GSI and cisplatin (CDDP) was also examined in these two types of cells. We observed that both CD133+ and CD133− cells proliferated at similar rates, but the cells exhibited distinctive differences in cell cycle progression. Few CD133+ cells were observed in the G{sub 2}/M phase, and there were half as many cells in S phase compared with the CD133− cells. Furthermore, CD133+ cells exhibited significant resistance to chemotherapy when treated with CDDP. The expression of Notch signaling pathway members, such as Notch1, Notch2 and Hes1, was lower in CD133+ cells. GSI slightly inhibited the proliferation of both cell types and exhibited little effect on the cell cycle. The inhibitory effects of DPP on these two types of cells were

  17. Blocking the NOTCH pathway can inhibit the growth of CD133-positive A549 cells and sensitize to chemotherapy

    International Nuclear Information System (INIS)

    Highlights: • Notch signaling pathway members are expressed lower levels in CD133+ cells. • CD133+ cells are not as sensitive as CD133− cells to chemotherapy. • GSI could inhibit the growth of both CD133+ and CD133− cells. • Blockade of Notch signaling pathway enhanced the effect of chemotherapy with CDDP. • DAPT/CDDP co-therapy caused G2/M arrest and elimination in CD133+ cells. - Abstract: Cancer stem cells (CSCs) are believed to play an important role in tumor growth and recurrence. These cells exhibit self-renewal and proliferation properties. CSCs also exhibit significant drug resistance compared with normal tumor cells. Finding new treatments that target CSCs could significantly enhance the effect of chemotherapy and improve patient survival. Notch signaling is known to regulate the development of the lungs by controlling the cell-fate determination of normal stem cells. In this study, we isolated CSCs from the human lung adenocarcinoma cell line A549. CD133 was used as a stem cell marker for fluorescence-activated cell sorting (FACS). We compared the expression of Notch signaling in both CD133+ and CD133− cells and blocked Notch signaling using the γ-secretase inhibitor DAPT (GSI-IX). The effect of combining GSI and cisplatin (CDDP) was also examined in these two types of cells. We observed that both CD133+ and CD133− cells proliferated at similar rates, but the cells exhibited distinctive differences in cell cycle progression. Few CD133+ cells were observed in the G2/M phase, and there were half as many cells in S phase compared with the CD133− cells. Furthermore, CD133+ cells exhibited significant resistance to chemotherapy when treated with CDDP. The expression of Notch signaling pathway members, such as Notch1, Notch2 and Hes1, was lower in CD133+ cells. GSI slightly inhibited the proliferation of both cell types and exhibited little effect on the cell cycle. The inhibitory effects of DPP on these two types of cells were enhanced

  18. Cell Cycle Control and Adhesion Molecule Expression in Cells of the Immune System are Sensitive to Altered Gravity

    Science.gov (United States)

    Ullrich, O.; Paulsen, K.; Thiel, C.; Herrmann, K.; Sang, C.; Han, G.; Hemmersbach, R.; von der Wiesche, M.; Kroll, H.; Zhuang, F.; Grote, K. H.; Cogoli, A.; Zipp, F.; Engelmann, F.

    2008-06-01

    Life on earth developed in the presence and under the constant influence of gravity. Thus, it is a fundamental biological question, whether gravity is required for cellular functions and signal transduction in mammalian cells. Since the first Spacelab-Mission 20 years ago, it is known that activation and function of T lymphocytes is severely suppressed in microgravity, but the underlying molecular mechanisms are not elucidated. Experiments have been performed using ground-based facilities such as fast-rotating clinostat and hyper-g-centrifuges, and real microgravity provided by parabolic flights. We found that 1.) cells of the immune system responded cell type specifically to altered gravity, 2.) microgravity induced a multitude of initial alterations in signal transduction, whereas 3.) hypergravity of 1.8g did not induce any changes of the pathways tested, and that 4.) most of the initially altered pathways in microgravity adapted to "normal" levels within 15min. However, some pathways remained altered and could explain cell cycle arrest of T lymphocytes as observed in several long-term space experiments.

  19. 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.

  20. 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

  1. 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

  2. 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.

  3. 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

  4. The Gonium pectorale genome demonstrates co-option of cell cycle regulation during the evolution of multicellularity.

    Science.gov (United States)

    Hanschen, Erik R; Marriage, Tara N; Ferris, Patrick J; Hamaji, Takashi; Toyoda, Atsushi; Fujiyama, Asao; Neme, Rafik; Noguchi, Hideki; Minakuchi, Yohei; Suzuki, Masahiro; Kawai-Toyooka, Hiroko; Smith, David R; Sparks, Halle; Anderson, Jaden; Bakarić, Robert; Luria, Victor; Karger, Amir; Kirschner, Marc W; Durand, Pierre M; Michod, Richard E; Nozaki, Hisayoshi; Olson, Bradley J S C

    2016-01-01

    The transition to multicellularity has occurred numerous times in all domains of life, yet its initial steps are poorly understood. The volvocine green algae are a tractable system for understanding the genetic basis of multicellularity including the initial formation of cooperative cell groups. Here we report the genome sequence of the undifferentiated colonial alga, Gonium pectorale, where group formation evolved by co-option of the retinoblastoma cell cycle regulatory pathway. Significantly, expression of the Gonium retinoblastoma cell cycle regulator in unicellular Chlamydomonas causes it to become colonial. The presence of these changes in undifferentiated Gonium indicates extensive group-level adaptation during the initial step in the evolution of multicellularity. These results emphasize an early and formative step in the evolution of multicellularity, the evolution of cell cycle regulation, one that may shed light on the evolutionary history of other multicellular innovations and evolutionary transitions. PMID:27102219

  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. 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...

  7. Impact of MAPK pathway activation in BRAFV600 melanoma on T cell and Dendritic Cell function

    Directory of Open Access Journals (Sweden)

    Patrick Alexander Ott

    2013-10-01

    Full Text Available Constitutive upregulation of the MAPK pathway by a BRAFV600 mutation occurs in about half of melanomas. This leads to increased oncogenic properties such as tumor cell invasion, metastatic potential, and resistance to apoptosis. Blockade of the MAPK pathway with highly specific kinase inhibitors induces unprecedented tumor response rates in patients with advanced BRAFV600 mutant melanoma. Immune checkpoint blockade with monoclonal antibodies targeting CTLA-4 and PD-1/PD-L1 has also demonstrated striking anti-tumor activity in patients with advanced melanoma. Tumor responses are likely limited by multiple additional layers of immune suppression in the tumor microenvironment. There is emerging preclinical and clinical evidence suggesting that MAPK inhibition has a beneficial effect on the immunosuppressive tumor microenvironment, providing a strong rationale for combined immunotherapy and MAPK pathway inhibition in melanoma. The T cell response has been the main focus in the studies reported to date. Since dendritic cells (DCs are important in the induction of tumor-specific T cell responses, the impact of MAPK pathway activation in melanoma on DC function is critical for the melanoma directed immune response. BRAFV600E melanoma cells modulate DC through the MAPK pathway because its blockade in melanoma cells can reverse suppression of DC function. As both MEK/BRAF inhibition and immune checkpoint blockade have recently taken center stage in the treatment of melanoma, a deeper understanding of how MAPK pathway inhibition affects the tumor immune response is needed.

  8. Glioblastoma: Molecular Pathways, Stem Cells and Therapeutic Targets

    International Nuclear Information System (INIS)

    Glioblastoma (GBM), a WHO-defined Grade IV astrocytoma, is the most common and aggressive CNS malignancy. Despite current treatment modalities, the survival time remains dismal. The main cause of mortality in patients with this disease is reoccurrence of the malignancy, which is attributed to treatment-resistant cancer stem cells within and surrounding the primary tumor. Inclusion of novel therapies, such as immuno- and DNA-based therapy, may provide better means of treating GBM. Furthermore, manipulation of recently discovered non-coding microRNAs, some of which regulate tumor growth through the development and maintenance of GBM stem cells, could provide new prospective therapies. Studies conducted by The Cancer Genome Atlas (TCGA) also demonstrate the role of molecular pathways, specifically the activated PI3K/AKT/mTOR pathway, in GBM tumorigenesis. Inhibition of the aforementioned pathway may provide a more direct and targeted method to GBM treatment. The combination of these treatment modalities may provide an innovative therapeutic approach for the management of GBM

  9. Glioblastoma: Molecular Pathways, Stem Cells and Therapeutic Targets

    Energy Technology Data Exchange (ETDEWEB)

    Jhanwar-Uniyal, Meena, E-mail: meena_jhanwar@nymc.edu; Labagnara, Michael; Friedman, Marissa; Kwasnicki, Amanda; Murali, Raj [Department of Neurosurgery, New York Medical College, Valhalla, NY 10595 (United States)

    2015-03-25

    Glioblastoma (GBM), a WHO-defined Grade IV astrocytoma, is the most common and aggressive CNS malignancy. Despite current treatment modalities, the survival time remains dismal. The main cause of mortality in patients with this disease is reoccurrence of the malignancy, which is attributed to treatment-resistant cancer stem cells within and surrounding the primary tumor. Inclusion of novel therapies, such as immuno- and DNA-based therapy, may provide better means of treating GBM. Furthermore, manipulation of recently discovered non-coding microRNAs, some of which regulate tumor growth through the development and maintenance of GBM stem cells, could provide new prospective therapies. Studies conducted by The Cancer Genome Atlas (TCGA) also demonstrate the role of molecular pathways, specifically the activated PI3K/AKT/mTOR pathway, in GBM tumorigenesis. Inhibition of the aforementioned pathway may provide a more direct and targeted method to GBM treatment. The combination of these treatment modalities may provide an innovative therapeutic approach for the management of GBM.

  10. Influence of Five Potential Anticancer Drugs on Wnt Pathway and Cell Survival in Human Biliary Tract Cancer Cells

    Directory of Open Access Journals (Sweden)

    Julia WACHTER, Daniel NEUREITER, Beate ALINGER, Martin PICHLER, Julia FUEREDER, Christian OBERDANNER, Pietro Di FAZIO, Matthias OCKER, Frieder BERR, Tobias KIESSLICH

    2012-01-01

    Full Text Available Background: The role of Wnt signalling in carcinogenesis suggests compounds targeting this pathway as potential anti-cancer drugs. Several studies report activation of Wnt signalling in biliary tract cancer (BTC thus rendering Wnt inhibitory drugs as potential candidates for targeted therapy of this highly chemoresistant disease.Methods: In this study we analysed five compounds with suggested inhibitory effects on Wnt signalling (DMAT, FH535, myricetin, quercetin, and TBB for their cytotoxic efficiency, mode of cell death, time- and cell line-dependent characteristics as well as their effects on Wnt pathway activity in nine different BTC cell lines.Results: Exposure of cancer cells to different concentrations of the compounds results in a clear dose-dependent reduction of viability for all drugs in the order FH535 > DMAT > TBB > myricetin > quercetin. The first three substances show high cytotoxicity in all tested cell lines, cause a direct cytotoxic effect by induction of apoptosis and inhibit pathway-specific signal transduction in a Wnt transcription factor reporter activity assay. Selected target genes such as growth-promoting cyclin D1 and the cell cycle progression inhibitor p27 are down- and up-regulated after treatment, respectively.Conclusions: Taken together, these data demonstrate that the small molecular weight inhibitors DMAT, F535 and TBB have a considerable cytotoxic and possibly Wnt-specific effect on BTC cell lines in vitro. Further in vivo investigation of these drugs as well as of new Wnt inhibitors may provide a promising approach for targeted therapy of this difficult-to-treat tumour.

  11. Pseudomonas putida KT2440 Strain Metabolizes Glucose through a Cycle Formed by Enzymes of the Entner-Doudoroff, Embden-Meyerhof-Parnas, and Pentose Phosphate Pathways.

    Science.gov (United States)

    Nikel, Pablo I; Chavarría, Max; Fuhrer, Tobias; Sauer, Uwe; de Lorenzo, Víctor

    2015-10-23

    The soil bacterium Pseudomonas putida KT2440 lacks a functional Embden-Meyerhof-Parnas (EMP) pathway, and glycolysis is known to proceed almost exclusively through the Entner-Doudoroff (ED) route. To investigate the raison d'être of this metabolic arrangement, the distribution of periplasmic and cytoplasmic carbon fluxes was studied in glucose cultures of this bacterium by using (13)C-labeled substrates, combined with quantitative physiology experiments, metabolite quantification, and in vitro enzymatic assays under both saturating and non-saturating, quasi in vivo conditions. Metabolic flux analysis demonstrated that 90% of the consumed sugar was converted into gluconate, entering central carbon metabolism as 6-phosphogluconate and further channeled into the ED pathway. Remarkably, about 10% of the triose phosphates were found to be recycled back to form hexose phosphates. This set of reactions merges activities belonging to the ED, the EMP (operating in a gluconeogenic fashion), and the pentose phosphate pathways to form an unforeseen metabolic architecture (EDEMP cycle). Determination of the NADPH balance revealed that the default metabolic state of P. putida KT2440 is characterized by a slight catabolic overproduction of reducing power. Cells growing on glucose thus run a biochemical cycle that favors NADPH formation. Because NADPH is required not only for anabolic functions but also for counteracting different types of environmental stress, such a cyclic operation may contribute to the physiological heftiness of this bacterium in its natural habitats. PMID:26350459

  12. 5-Lipoxygenase Pathway, Dendritic Cells, and Adaptive Immunity

    Directory of Open Access Journals (Sweden)

    Hedi Harizi

    2004-01-01

    Full Text Available 5-lipoxygenase (5-LO pathway is the major source of potent proinflammatory leukotrienes (LTs issued from the metabolism of arachidonic acid (AA, and best known for their roles in the pathogenesis of asthma. These lipid mediators are mainly released from myeloid cells and may act as physiological autocrine and paracrine signalling molecules, and play a central role in regulating the interaction between innate and adaptive immunity. The biological actions of LTs including their immunoregulatory and proinflammatory effects are mediated through extracellular specific G-protein-coupled receptors. Despite their role in inflammatory cells, such as neutrophils and macrophages, LTs may have important effects on dendritic cells (DC-mediated adaptive immunity. Several lines of evidence show that DC not only are important source of LTs, but also become targets of their actions by producing other lipid mediators and proinflammatory molecules. This review focuses on advances in 5-LO pathway biology, the production of LTs from DC and their role on various cells of immune system and in adaptive immunity.

  13. Aberrant signaling pathways in medulloblastomas: a stem cell connection

    Directory of Open Access Journals (Sweden)

    Carolina Oliveira Rodini

    2010-12-01

    Full Text Available Medulloblastoma is a highly malignant primary tumor of the central nervous system. It represents the most frequent type of solid tumor and the leading cause of death related to cancer in early childhood. Current treatment includes surgery, chemotherapy and radiotherapy which may lead to severe cognitive impairment and secondary brain tumors. New perspectives for therapeutic development have emerged with the identification of stem-like cells displaying high tumorigenic potential and increased radio- and chemo-resistance in gliomas. Under the cancer stem cell hypothesis, transformation of neural stem cells and/or granular neuron progenitors of the cerebellum are though to be involved in medulloblastoma development. Dissecting the genetic and molecular alterations associated with this process should significantly impact both basic and applied cancer research. Based on cumulative evidences in the fields of genetics and molecular biology of medulloblastomas, we discuss the possible involvement of developmental signaling pathways as critical biochemical switches determining normal neurogenesis or tumorigenesis. From the clinical viewpoint, modulation of signaling pathways such as TGFβ, regulating neural stem cell proliferation and tumor development, might be attempted as an alternative strategy for future drug development aiming at more efficient therapies and improved clinical outcome of patients with pediatric brain cancers.

  14. 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

  15. 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.

  16. 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.

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

    Directory of Open Access Journals (Sweden)

    Italo Mario Cesari

    2014-01-01

    Full Text Available Methyl jasmonate (MJ, an oxylipid that induces defense-related mechanisms in plants, has been shown to be active against cancer cells both in vitro and in vivo, without affecting normal cells. Here we review most of the described MJ activities in an attempt to get an integrated view and better understanding of its multifaceted modes of action. MJ (1 arrests cell cycle, inhibiting cell growth and proliferation, (2 causes cell death through the intrinsic/extrinsic proapoptotic, p53-independent apoptotic, and nonapoptotic (necrosis pathways, (3 detaches hexokinase from the voltage-dependent anion channel, dissociating glycolytic and mitochondrial functions, decreasing the mitochondrial membrane potential, favoring cytochrome c release and ATP depletion, activating pro-apoptotic, and inactivating antiapoptotic proteins, (4 induces reactive oxygen species mediated responses, (5 stimulates MAPK-stress signaling and redifferentiation in leukemia cells, (6 inhibits overexpressed proinflammatory enzymes in cancer cells such as aldo-keto reductase 1 and 5-lipoxygenase, and (7 inhibits cell migration and shows antiangiogenic and antimetastatic activities. Finally, MJ may act as a chemosensitizer to some chemotherapics helping to overcome drug resistant. The complete lack of toxicity to normal cells and the rapidity by which MJ causes damage to cancer cells turn MJ into a promising anticancer agent that can be used alone or in combination with other agents.

  18. Double strand break repair: two mechanisms in competition but tightly linked to cell cycle

    International Nuclear Information System (INIS)

    DNA double strand breaks (DSB) are highly toxic damage although they can be induced to create genetic diversity. Two distinct pathways can repair DSB: Homologous Recombination (HR) and Non Homologous End Joining (NHEJ). If un- or mis-repaired, this damage can lead to cancer. Thus, it is essential to investigate how these two pathways are regulated for DSB repair. NHEJ inhibition leads to HR DSB repair stimulation. However, this channeling to HR is tightly linked to cell cycle since NHEJ and HR are active in G1/early S and late S/G2, respectively. Our results suggest that G1-unrepaired DSB go through S phase to be repaired by HR in G2. Those results allow a better understanding of DSB repair mechanisms regulation. (author)

  19. Mammalian target of rapamycin pathway inhibition enhances the effects of 5-aza-dC on suppressing cell proliferation in human gastric cancer cell lines

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    The present study aimed to evaluate the relationship between mTOR signaling pathway and DNA methylation in cell survival,cell cycle,gene expression and protein level on human gastric cancer cells. Human gastric cancer cell lines,MKN45 and SGC7901 were treated with 5-aza-dC,rapamycin and/or LY294002.Cell viability was analyzed by MTT.Cell cycle distribution was evaluated by flow cytometry (FCM).The transcription level of PTEN and p27 Kip1 genes was detected by using real-time PCR.Protein expressions were detected by Western blotting.We found that cell viability was moderately reduced when treated with 5-aza-dC alone,but remarkably reduced when mTOR pathway was inhibited together (P<0.01).mTOR inhibition enhances the effects of 5-aza-dC on arresting cell cycle at G2 phase in human gastric cancer cell lines.The expression of PTEN and p27 Kip1 mRNA was remarkably increased in the gastric cancer cells treated with combind drugs(P<0.01).Phosphorylation of Akt,p70S6K and 4E-BP1 were significantly reduced in the cells treated with LY294002 or RAPA(P<0.01),but we failed to find that 5-aza-dC enhance these effects.We suggested that mTOR inhibition could enhance the effects of 5-aza-dC on suppressing cell proliferation and arresting cell cycle in human gastric cancer cell lines, which might be a potential target for tumor therapy.

  20. 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

  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. 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.

  3. Apoptosis pathway of liver cells in chronic hepatitis

    Institute of Scientific and Technical Information of China (English)

    Nai-Ling Chen; Zhen-Qiu Zhou; Ling Bai; Lin Li; Pei-Lan Chen; Chang Zhang; Chao-Ying Liu; Tao Deng; Hao Chen; Ke-Ming Jia

    2004-01-01

    AIM: To study the pathway of apoptosis in chronic liver disease and the role of mitochondria in programmed cell death.METHODS: Liver biopsy specimens from 72 cases of chronic hepatitis and 29 cases of post hepatitis cirrhosis were studied. The pro-apoptotic protein Fas, FasL, Bax and the anti-apoptotic protein Bcl-2, Bcl-xL, Bcl-2α were studied immunohistochemically by SP method. Specimens from 15 cases of chronic hepatitis and post hepatitis cirrhosis were examined for their ultramicrostructures with special attention to their mitochondrial changes. Specimens from 3 normal adults (demised in traffic accidents) were used as control.RESULTS: The expression of proapoptotic proteins (Fas,FasL, Bax) in hepatocytes was significantly higher in the chronic hepatitis group than in the cirrhosis group (P<0.001).In the study of ultramicrostructure 364 hepatocytes were examined, from 12 cases of chronic hepatitis (including 10mild cases, 1 moderate case and 1 severe case). Out of 364 hepatocytes 40 (11.0%) hepatocytes were found with various kinds of destruction in their mitochondria. Rupture of the outer membrane of mitochondria and the leakage of matrix from the intermembrane space were definitely demonstrated. The ultramicrostructural changes of mitochondria in the chronic hepatitis group were statistically higher than that in normal adults control group (χ2=4.32, P<0.05).CONCLUSION: The result of the study was in support of the current view that the apoptotic process in chronic hepatitis patients were largely along the intrinsic pathway (mitochondrial pathway), given that the intrinsic and extrinsic pathways could interlinked (converged) at some point on their progression, also it is impossible at present to exclude the possibility that the two pathways could be chosen by hepatocytes in parallel simultaneously.

  4. Role of the fission yeast cell integrity MAPK pathway in response to glucose limitation

    Directory of Open Access Journals (Sweden)

    Madrid Marisa

    2013-02-01

    Full Text Available Abstract Background Glucose is a signaling molecule which regulates multiple events in eukaryotic organisms and the most preferred carbon source in the fission yeast Schizosaccharomyces pombe. The ability of this yeast to grow in the absence of glucose becomes strongly limited due to lack of enzymes of the glyoxylate cycle that support diauxic growth. The stress-activated protein kinase (SAPK pathway and its effectors, Sty1 MAPK and transcription factor Atf1, play a critical role in the adaptation of fission yeast to grow on alternative non-fermentable carbon sources by inducing the expression of fbp1+ gene, coding for the gluconeogenic enzyme fructose-1,6-bisphosphatase. The cell integrity Pmk1 pathway is another MAPK cascade that regulates various processes in fission yeast, including cell wall construction, cytokinesis, and ionic homeostasis. Pmk1 pathway also becomes strongly activated in response to glucose deprivation but its role during glucose exhaustion and ensuing adaptation to respiratory metabolism is currently unknown. Results We found that Pmk1 activation in the absence of glucose takes place only after complete depletion of this carbon source and that such activation is not related to an endogenous oxidative stress. Notably, Pmk1 MAPK activation relies on de novo protein synthesis, is independent on known upstream activators of the pathway like Rho2 GTPase, and involves PKC ortholog Pck2. Also, the Glucose/cAMP pathway is required operative for full activation of the Pmk1 signaling cascade. Mutants lacking Pmk1 displayed a partial growth defect in respiratory media which was not observed in the presence of glucose. This phenotype was accompanied by a decreased and delayed expression of transcription factor Atf1 and target genes fbp1+ and pyp2+. Intriguingly, the kinetics of Sty1 activation in Pmk1-less cells was clearly altered during growth adaptation to non-fermentable carbon sources. Conclusions Unknown upstream elements

  5. Targeting ceramide metabolic pathway induces apoptosis in human breast cancer cell lines

    International Nuclear Information System (INIS)

    The sphingolipid ceramide is a pro apoptotic molecule of ceramide metabolic pathway and is hydrolyzed to proliferative metabolite, sphingosine 1 phosphate by the action of acid ceramidase. Being upregulated in the tumors of breast, acid ceramidase acts as a potential target for breast cancer therapy. We aimed at targeting this enzyme with a small molecule acid ceramidase inhibitor, Ceranib 2 in human breast cancer cell lines MCF 7 and MDA MB 231. Ceranib 2 effectively inhibited the growth of both the cell lines in dose and time dependant manner. Morphological apoptotic hallmarks such as chromatin condensation, fragmented chromatin were observed in AO/EtBr staining. Moreover, ladder pattern of fragmented DNA observed in DNA gel electrophoresis proved the apoptotic activity of Ceranib 2 in breast cancer cell lines. The apoptotic events were associated with significant increase in the expression of pro-apoptotic genes (Bad, Bax and Bid) and down regulation of anti-apoptotic gene (Bcl 2). Interestingly, increase in sub G1 population of cell cycle phase analysis and elevated Annexin V positive cells after Ceranib 2 treatment substantiated its apoptotic activity in MCF 7 and MDA MB 231 cell lines. Thus, we report Ceranib 2 as a potent therapeutic agent against both ER+ and ER− breast cancer cell lines. - Highlights: • Acid Ceramidase inhibitor, Ceranib 2 induced apoptosis in Breast cancer cell lines (MCF 7 and MDA MB 231 cell lines). • Apoptosis is mediated by DNA fragmentation and cell cycle arrest. • Ceranib 2 upregulated the expression of pro-apoptotic genes and down regulated anti-apoptotic gene expression. • More potent compared to the standard drug Tamoxifen

  6. Targeting ceramide metabolic pathway induces apoptosis in human breast cancer cell lines

    Energy Technology Data Exchange (ETDEWEB)

    Vethakanraj, Helen Shiphrah; Babu, Thabraz Ahmed; Sudarsanan, Ganesh Babu; Duraisamy, Prabhu Kumar; Ashok Kumar, Sekar, E-mail: sekarashok@gmail.com

    2015-08-28

    The sphingolipid ceramide is a pro apoptotic molecule of ceramide metabolic pathway and is hydrolyzed to proliferative metabolite, sphingosine 1 phosphate by the action of acid ceramidase. Being upregulated in the tumors of breast, acid ceramidase acts as a potential target for breast cancer therapy. We aimed at targeting this enzyme with a small molecule acid ceramidase inhibitor, Ceranib 2 in human breast cancer cell lines MCF 7 and MDA MB 231. Ceranib 2 effectively inhibited the growth of both the cell lines in dose and time dependant manner. Morphological apoptotic hallmarks such as chromatin condensation, fragmented chromatin were observed in AO/EtBr staining. Moreover, ladder pattern of fragmented DNA observed in DNA gel electrophoresis proved the apoptotic activity of Ceranib 2 in breast cancer cell lines. The apoptotic events were associated with significant increase in the expression of pro-apoptotic genes (Bad, Bax and Bid) and down regulation of anti-apoptotic gene (Bcl 2). Interestingly, increase in sub G1 population of cell cycle phase analysis and elevated Annexin V positive cells after Ceranib 2 treatment substantiated its apoptotic activity in MCF 7 and MDA MB 231 cell lines. Thus, we report Ceranib 2 as a potent therapeutic agent against both ER{sup +} and ER{sup −} breast cancer cell lines. - Highlights: • Acid Ceramidase inhibitor, Ceranib 2 induced apoptosis in Breast cancer cell lines (MCF 7 and MDA MB 231 cell lines). • Apoptosis is mediated by DNA fragmentation and cell cycle arrest. • Ceranib 2 upregulated the expression of pro-apoptotic genes and down regulated anti-apoptotic gene expression. • More potent compared to the standard drug Tamoxifen.

  7. Downregulation of RSK2 influences the biological activities of human osteosarcoma cells through inactivating AKT/mTOR signaling pathways.

    Science.gov (United States)

    Qiu, Quanhe; Jiang, Jing; Lin, Liangbo; Cheng, Si; Xin, Daqi; Jiang, Wei; Shen, Jieliang; Hu, Zhenming

    2016-06-01

    RSK2 (90 kDa ribosomal S6 kinase) is a downstream effector of the Ras/ERK (extracellular signal-regulated kinase) signaling pathway that has major functions in cell biological activities, including regulating nuclear signaling, cell cycle progression, cell proliferation, cell growth, protein synthesis, cell migration and cell survival, and is expressed in most types of human malignant tumors, including lung cancer, prostate and breast tumors, skin cancer and osteosarcomas (OS). RSK2 was found to be essential for osteosarcoma formation. To investigate whether RSK2 is expressed at high levels in human osteosarcome tissues and whether its expression is correlated with the aggressive biological behavior of osteosarcoma cell line (OCLs), we assessed the association between RSK2 expression and OS cell progression, as well as the effects of RSK2 inhibition on the biological activities of osteosarcoma cells. We performed immunohistochemistry to analyze the expression of RSK2 in specimens from 30 humans with osteosarcoma, and 15 normal tissues. RSK2 gene expression levels in 30 specimens with osteosarcoma were significantly higher than those of normal tissues. We performed RNA interference on three OCLs to evaluate cell apoptosis, cell growth, cell proliferation, cell motility, chemosensitivity and oncogenicity. After transfection with RSK2 shRNA, increased cell apoptosis, cell growth inhibition, cell cycle progression, weaker cell proliferation, cell migration and weaker tumor formation were observed in all OCLs. These results suggested that RSK2 expression may mediate the biological activities of OS cells and RSK2 may be an effective therapeutic target for the treatment of osteosarcomas. The AKT/mTOR, MAPK/ERK/c-Fos and Bcl2/Bax pathways were analysed to clarify the mechanisms involved. PMID:27082640

  8. 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....

  9. 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...

  10. 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

  11. 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.

  12. ALDH maintains the stemness of lung adenoma stem cells by suppressing the Notch/CDK2/CCNE pathway.

    Directory of Open Access Journals (Sweden)

    Zhongjun Li

    Full Text Available To evaluate the expression of ALDH1A1 in lung adenoma stem cells (LASCs and maintenance of their stemness through the Notch pathway.LASCs (A549s were isolated from lung adenoma cells (A549 and identified by their coexpression of CD133 and CD326 and their capacity formulti-directional differentiation. Expression of ALDH1A1 in A549 and A549s cells were evaluated by Real-time PCR. Effects of ALDH1A1 upregulation in A549 cells and its downregulation in A549s cells on the clonogenicity and cell cycle were assessed by colony-forming unit assay. Moreover, the effects of ALDH1A1 on the Notch pathway, and thus on the cell cycle, were studied.A549s cells were successfully isolated and identified.ALDH1A1expression was significantly higher in A549s than in A549 cells. Clonogenicity was significantly decreased in A549s cells treated with ALDH1A1 siRNA. Duration of the G1 stage of the cell cycle increased after ALDH1A1 was overexpressed, or decreased with ALDH1A1 siRNA. ALDH1A1, Notch1, -2, and -3, CDK2, and CCNE1 expression levels were higher in A549s cells than in A549 cells. Expression of Notch1, -2, and -3, CDK2, and CCNE1 was significantly decreased by upregulation of ALDH1A1 in A549 cells, but increased by its interruption in A549s cells. When Notch3 or CDK2 expression was downregulated, the expression levels of ALDH1A1, Notch1, -2, and -3, CDK2, and CCNE1 were reduced in all cell types.ALDH1A1 expression improved clonogenicity and inhibited the cell cycle, maintaining the stemness of the A549s cells; this may involve suppression of the Notch/CDK2/Cyclin pathway.

  13. 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

  14. 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...

  15. 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

  16. 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.

  17. 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.

  18. 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

  19. 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.

  20. 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

  1. An alternative pathway for signal flow from rod photoreceptors to ganglion cells in mammalian retina.

    OpenAIRE

    DeVries, S H; Baylor, D A

    1995-01-01

    Rod signals in the mammalian retina are thought to reach ganglion cells over the circuit rod-->rod depolarizing bipolar cell-->AII amacrine cell-->cone bipolar cells-->ganglion cells. A possible alternative pathway involves gap junctions linking the rods and cones, the circuit being rod-->cone-->cone bipolar cells-->ganglion cells. It is not clear whether this second pathway indeed relays rod signals to ganglion cells. We studied signal flow in the isolated rabbit retina with a multielectrode...

  2. 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.

  3. Biotic and abiotic pathways of phosphorus cycling in minerals and sediments: insights from oxygen isotopes in phosphate

    Energy Technology Data Exchange (ETDEWEB)

    Jaisi, Deb P.; Kukkadapu, Ravi K.; Stout, Lisa M.; Varga, Tamas; Blake, Ruth E.

    2011-07-06

    A key question to address in the development of oxygen isotope ratios in phosphate (18Op) as a tracer of biogeochemical cycling of phosphorus in ancient and modern environments is the nature of isotopic signatures associated with uptake and cycling of mineral-bound phosphate by microorganisms. Here we present experimental results aimed at understanding the biotic and abiotic pathway of P cycling during biological uptake of phosphate sorbed to ferrihydrite and the selective uptake of specific sedimentary phosphate phases by Escherichia coli, Vibrio fischeri and Marinobacter aquaeolei. Results indicate that a significant fraction of ferrihydrite-bound phosphate is biologically available. The fraction of phosphate taken up by E. coli attained an equilibrium isotopic composition in a short time (<50 hrs) due to efficient O-isotope exchange between phosphate and water (biotic pathway). The difference in isotopic composition between newly equilibrated aqueous and residual sorbed phosphate promoted the exchange of intact phosphate radicals (abiotic pathway) so that this difference gradually became negligible. In sediment containing different P phases, E. coli and V. fischeri ‘extracted’ loosely sorbed phosphate first while M. aquaeolei preferred iron-oxide bound phosphate. Each bacterium imprinted a biotic isotopic signature on each P phase that it took up and cycled. For example, the 18Op value of the sorbed phosphate phase shifted gradually towards equilibrium isotopic composition and the value of Fe oxide-bound phosphate showed slight changes at first, but when new iron oxides were formed, co-precipitated/occluded phosphate retained 18O values of aqueous phosphate at that time. Concentrations and isotopic compositions of authigenic and detrital phosphates did not change, suggesting that these phosphate phases were not utilized by bacteria. These findings support burgeoning applications of 18Op as a tracer of phosphorus cycling in sediments, soils and aquatic

  4. Transcriptome-Based Analysis of Molecular Pathways for Clusterin Functions in Kidney Cells.

    Science.gov (United States)

    Dairi, Ghida; Guan, Qiunong; Roshan-Moniri, Mani; Collins, Colin C; Ong, Christopher J; Gleave, Martin E; Nguan, Christopher Y C; Du, Caigan

    2016-12-01

    Clusterin (CLU) is a chaperone-like protein and plays a protective role against renal ischemia-reperfusion injury (IRI); however, the molecular pathways for its functions in the kidney are not fully understood. This study was designed to investigate CLU-mediating pathways in kidney cells by using bioinformatics analysis. CLU null renal tubular epithelial cells (TECs) expressing human CLU cDNA (TEC-CLU(hCLU) ) or empty vector (TEC-CLU(-/-) ) were exposed to normoxia or hypoxia (1% O2 ). Transcriptome profiling with a significant twofold change was performed using SurePrint G3 Mouse Gene Expression 8 × 60 K microarray, and the signaling pathways was ranked by using Ingenuity pathway analysis. Here, we showed that compared to CLU null controls, ectopic expression of human CLU in CLU null kidney cells promoted cell growth but inhibited migration in normoxia, and enhanced cell survival in hypoxia. CLU expression affected expression of 3864 transcripts (1893 up-regulated) in normoxia and 3670 transcripts (1925 up-regulated) in hypoxia. CLU functions in normoxia were associated mostly with AKT2/PPP2R2B-dependent PI3K/AKT, PTEN, VEGF, and ERK/MAPK signaling and as well with GSK3B-mediated cell cycle progression. In addition to unfolded protein response (UPR) and/or endoplasmic reticulum (ER) stress, CLU-enhanced cell survival in hypoxia was also associated with PIK3CD/MAPK1-dependent PI3K/AKT, HIF-α, PTEN, VEGF, and ERK/MAPK signaling. In conclusion, our data showed that CLU functions in kidney cells were mainly mediated in a cascade manner by PI3K/AKT, PTEN, VEGF, and ERK/MAPK signaling, and specifically by activation of UPR/ER stress in hypoxia, providing new insights into the protective role of CLU in the kidney. J. Cell. Physiol. 231: 2628-2638, 2016. © 2016 Wiley Periodicals, Inc. PMID:27155085

  5. Inhibition of Jak-STAT3 pathway enhances bufalin-induced apoptosis in colon cancer SW620 cells

    Directory of Open Access Journals (Sweden)

    Zhu Zhitu

    2012-10-01

    Full Text Available Abstract Background The purpose of the research is to investigate the roles of Jak-STAT3 signaling pathway in bufalin-induced apoptosis in colon cancer SW620 cells. Methods The inhibitory effects of bufalin on cell proliferation were determined by MTT (Methyl thiazolyltetrazolium assay. The morphological changes of cells were measured by Wright-Giemsa staining. The cell cycle arrest and apoptosis were tested by flow cytometry analysis. Western Blot was used to determine the protein expression of the apoptosis inhibitors livin and caspase-3, the apoptosis-related proteins Bax and Bcl-2, as well as the key protein kinases in the Jak-stat3 signaling pathway, stat3 and p-stat3. Results (1 Bufalin inhibited the proliferation of SW620 cells. IC50 at 24 h, 48 h and 72 h were 76.72 ± 6.21 nmol/L, 34.05 ± 4.21 nmol/L and 16.7 ± 6.37 nmol/L. (2 Bufalin induced SW620 cell cycle arrest and apoptosis, indicated by the appearance of apoptotic bodies; (3 The results from flow cytometry demonstrated that there was cell cycle G2/M phase arrest in 20 nmol/L bufalin treatment group (36.29 ± 2.11% vs 18.39 ± 1.74%, P Conclusions Bufalin not only inhibited the growth of colon cancer SW620 cells, but also induced apoptosis of SW620 cells. Activation of caspase-3, up-regulation of Bax, down-regulation of livin and Bcl-2, as well as inhibition of Jak-stat3 signaling pathway might be the important mechanisms for the bufalin-induced apoptosis.

  6. 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 ...

  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. USP22 promotes epithelial-mesenchymal transition via the FAK pathway in pancreatic cancer cells.

    Science.gov (United States)

    Ning, Zhen; Wang, Aman; Liang, Jinxiao; Xie, Yunpeng; Liu, Jiwei; Yan, Qiu; Wang, Zhongyu

    2014-10-01

    Epithelial-mesenchymal transition (EMT) contributes to the occurrence and development of tumors, particularly to the promotion of tumor invasion and metastasis. As a newly discovered ubiquitin hydrolase family member, USP22 plays a key role in the malignant transformation of tumors and the regulation of the cell cycle. However, recent studies on USP22 have primarily focused on its role in cell cycle regulation, and the potential mechanism underlying the promotion of tumor invasion and metastasis by abnormal USP22 expression has not been reported. Our studies revealed that the overexpression of USP22 in PANC-1 cells promoted Ezrin redistribution and phosphorylation and cytoskeletal remodeling, upregulated expression of the transcription factors Snail and ZEB1 to promote EMT, and increased cellular invasion and migration. In contrast, blockade of USP22 expression resulted in the opposite effects. In addition, the focal adhesion kinase (FAK) signaling pathway was shown to play a key role in the process of EMT induction in PANC-1 cells by USP22. Thus, the present study suggests that USP22 acts as a regulatory protein for EMT in pancreatic cancer, which may provide a new approach for the targeted therapy of pancreatic cancer. PMID:25070659

  9. Proteomic analysis of pathways involved in estrogen-induced growth and apoptosis of breast cancer cells.

    Directory of Open Access Journals (Sweden)

    Zhang-Zhi Hu

    Full Text Available BACKGROUND: Estrogen is a known growth promoter for estrogen receptor (ER-positive breast cancer cells. Paradoxically, in breast cancer cells that have been chronically deprived of estrogen stimulation, re-introduction of the hormone can induce apoptosis. METHODOLOGY/PRINCIPAL FINDINGS: Here, we sought to identify signaling networks that are triggered by estradiol (E2 in isogenic MCF-7 breast cancer cells that undergo apoptosis (MCF-7:5C versus cells that proliferate upon exposure to E2 (MCF-7. The nuclear receptor co-activator AIB1 (Amplified in Breast Cancer-1 is known to be rate-limiting for E2-induced cell survival responses in MCF-7 cells and was found here to also be required for the induction of apoptosis by E2 in the MCF-7:5C cells. Proteins that interact with AIB1 as well as complexes that contain tyrosine phosphorylated proteins were isolated by immunoprecipitation and identified by mass spectrometry (MS at baseline and after a brief exposure to E2 for two hours. Bioinformatic network analyses of the identified protein interactions were then used to analyze E2 signaling pathways that trigger apoptosis versus survival. Comparison of MS data with a computationally-predicted AIB1 interaction network showed that 26 proteins identified in this study are within this network, and are involved in signal transduction, transcription, cell cycle regulation and protein degradation. CONCLUSIONS: G-protein-coupled receptors, PI3 kinase, Wnt and Notch signaling pathways were most strongly associated with E2-induced proliferation or apoptosis and are integrated here into a global AIB1 signaling network that controls qualitatively distinct responses to estrogen.

  10. Early transcriptional response to aminoglycoside antibiotic suggests alternate pathways leading to apoptosis of sensory hair cells in the mouse inner ear

    Directory of Open Access Journals (Sweden)

    Neil eSegil

    2015-05-01

    Full Text Available Aminoglycoside antibiotics are the drug of choice for treating many bacterial infections, but their administration results in hearing loss in nearly one fourth of the patients who receive them. Several biochemical pathways have been implicated in aminoglycoside antibiotic ototoxicity; however, little is known about how hair cells respond to aminoglycoside antibiotics at the transcriptome level. Here we have investigated the genome-wide response to the aminoglycoside antibiotic gentamicin. Using organotypic cultures of the perinatal organ of Corti, we performed RNA sequencing using cDNA libraries obtained from FACS-purified hair cells. Within 3 hours of gentamicin treatment, the messenger RNA level of more than three thousand genes in hair cells changed significantly. Bioinformatic analysis of these changes highlighted several known signal transduction pathways, including the JNK pathway and the NF-κB pathway, in addition to genes involved in the stress response, apoptosis, cell cycle control, and DNA damage repair. In contrast, only 698 genes, mainly involved in cell cycle and metabolite biosynthetic processes, were significantly affected in the non-hair cell population. The gene expression profiles of hair cells in response to gentamicin share a considerable similarity with those previously observed in gentamicin-induced nephrotoxicity. Our findings suggest that previously observed early responses to gentamicin in hair cells in specific signaling pathways are reflected in changes in gene expression. Additionally, the observed changes in gene expression of cell cycle regulatory genes indicate a disruption of the postmitotic state, which may suggest an alternative pathway regulating gentamicin-induced hair cell death. This work provides a more comprehensive view of aminoglycoside antibiotic ototoxicity, and thus contribute to identifying potential pathways or therapeutic targets to alleviate this important side effect of aminoglycoside

  11. Two pathways of DNA double-strand break repair in G1 cells of Saccharomyces cerevisiae

    International Nuclear Information System (INIS)

    The G1 cells of the diploid yeast Saccharomyces cerevislae are known to be capable of a slow repair of DNA double-strand breaks (DSB) during holding the cells in a non-nutrient medium. In the present paper, it has been shown that S. cerevislae cells γ-irradiated in the G1 phase of cell cycle are capable of fast repair of DNA DSB; this process is completed within 30-40 min of holding the cells in water at 28 deg C. For this reason, the kinetics of DNA DSB repair during holding the cells in a non-nutrient medium are biphasic, i.e., the first, ''fast'' phase is completed within 30-40 min; wheras the second, ''slow'' one, within 48 h. Mutations rad51, rad52, rad54 and rad55 inhibit the fast repair of DNA DSB, whereas mutations rad50, rad53 and rad57 do not practically influence this process. It has been shown that the observed fast and slow repair of DNA DSB in the G1 diploid cells of S, cerevislae are separate pathways of DNA DSB repair in yeast

  12. Plumbagin induces apoptosis in Her2-overexpressing breast cancer cells through the mitochondrial-mediated pathway.

    Science.gov (United States)

    Kawiak, Anna; Zawacka-Pankau, Joanna; Lojkowska, Ewa

    2012-04-27

    Breast cancer is the leading cause of death-related cancers in women. Approximately 30% of breast cancers overexpress the Her2 oncogene, which is associated with a poor prognosis and increased resistance to chemotherapy. Plumbagin (1), a constituent of species in the plant genera Drosera and Plumbago, displays antineoplastic activity toward various cancers. The present study was aimed at determining the anticancer potential of 1 toward Her2-overexpressing breast cancer cells and defining the mode of cell death induced in these cells. The results showed that 1 exhibited high antiproliferative activity toward the Her2-overexpressing cell lines SKBR3 and BT474. The antiproliferative activity of 1 was associated with apoptosis-mediated cell death, as revealed by caspase activation and an increase in the sub-G1 fraction of the cell cycle. Compound 1 increased the levels of the proapoptotic Bcl-2 family of proteins and decreased the level of the antiapoptotic Bcl-2 protein in SKBR3 and BT474 cells. Thus, these findings indicate that 1 induces apoptosis in Her2-overexpressing breast cancers through the mitochondrial-mediated pathway and suggest its potential for further investigation for the treatment of Her2-overexpressing breast cancer. PMID:22512718

  13. Escin Chemosensitizes Human Pancreatic Cancer Cells and Inhibits the Nuclear Factor-kappaB Signaling Pathway.

    Science.gov (United States)

    Rimmon, A; Vexler, A; Berkovich, L; Earon, G; Ron, I; Lev-Ari, S

    2013-01-01

    Background. There is an urgent need to develop new treatment strategies and drugs for pancreatic cancer that is highly resistant to radio-chemotherapy. Aesculus hippocastanum (the horse chestnut) known in Chinese medicine as a plant with anti-inflammatory, antiedema, antianalgesic, and antipyretic activities. The main active compound of this plant is Escin (C54H84O23). Objective. To evaluate the effect of Escin alone and combined with chemotherapy on pancreatic cancer cell survival and to unravel mechanism(s) of Escin anticancer activity. Methods. Cell survival was measured by XTT colorimetric assay. Synergistic effect of combined therapy was determined by CalcuSyn software. Cell cycle and induction of apoptosis were evaluated by FACS analysis. Expression of NF- κ B-related proteins (p65, I κ Bα, and p-I κ Bα) and cyclin D was evaluated by western blot analysis. Results. Escin decreased the survival of pancreatic cancer cells with IC50 = 10-20 M. Escin combined with gemcitabine showed only additive effect, while its combination with cisplatin resulted in a significant synergistic cytotoxic effect in Panc-1 cells. High concentrations of Escin induced apoptosis and decreased NF- κ B-related proteins and cyclin D expression. Conclusions. Escin decreased pancreatic cancer cell survival, induced apoptosis, and downregulated NF- κ B signaling pathway. Moreover, Escin sensitized pancreatic cancer cells to chemotherapy. Further translational research is required. PMID:24282639

  14. Characterization of glucose-related metabolic pathways in differentiated rat oligodendrocyte lineage cells.

    Science.gov (United States)

    Amaral, Ana I; Hadera, Mussie G; Tavares, Joana M; Kotter, Mark R N; Sonnewald, Ursula

    2016-01-01

    Although oligodendrocytes constitute a significant proportion of cells in the central nervous system (CNS), little is known about their intermediary metabolism. We have, therefore, characterized metabolic functions of primary oligodendrocyte precursor cell cultures at late stages of differentiation using isotope-labelled metabolites. We report that differentiated oligodendrocyte lineage cells avidly metabolize glucose in the cytosol and pyruvate derived from glucose in the mitochondria. The labelling patterns of metabolites obtained after incubation with [1,2-(13)C]glucose demonstrated that the pentose phosphate pathway (PPP) is highly active in oligodendrocytes (approximately 10% of glucose is metabolized via the PPP as indicated by labelling patterns in phosphoenolpyruvate). Mass spectrometry and magnetic resonance spectroscopy analyses of metabolites after incubation of cells with [1-(13)C]lactate or [1,2-(13)C]glucose, respectively, demonstrated that anaplerotic pyruvate carboxylation, which was thought to be exclusive to astrocytes, is also active in oligodendrocytes. Using [1,2-(13)C]acetate, we show that oligodendrocytes convert acetate into acetyl CoA which is metabolized in the tricarboxylic acid cycle. Analysis of labelling patterns of alanine after incubation of cells with [1,2-(13)C]acetate and [1,2-(13)C]glucose showed catabolic oxidation of malate or oxaloacetate. In conclusion, we report that oligodendrocyte lineage cells at late differentiation stages are metabolically highly active cells that are likely to contribute considerably to the metabolic activity of the CNS. PMID:26352325

  15. Essential Gene Pathways for Glioblastoma Stem Cells: Clinical Implications for Prevention of Tumor Recurrence

    International Nuclear Information System (INIS)

    Glioblastoma (World Health Organization/WHO grade IV) is the most common and most aggressive adult glial tumor. Patients with glioblastoma, despite being treated with gross total resection and post-operative radiation/chemotherapy, will almost always develop tumor recurrence. Glioblastoma stem cells (GSC), a minor subpopulation within the tumor mass, have been recently characterized as tumor-initiating cells and hypothesized to be responsible for post-treatment recurrence because of their enhanced radio-/chemo-resistant phenotype and ability to reconstitute tumors in mouse brains. Genome-wide expression profile analysis uncovered molecular properties of GSC distinct from their differentiated, proliferative progeny that comprise the majority of the tumor mass. In contrast to the hyperproliferative and hyperangiogenic phenotype of glioblastoma tumors, GSC possess neuroectodermal properties and express genes associated with neural stem cells, radial glial cells, and neural crest cells, as well as portray a migratory, quiescent, and undifferentiated phenotype. Thus, cell cycle-targeted radio-chemotherapy, which aims to kill fast-growing tumor cells, may not completely eliminate glioblastoma tumors. To prevent tumor recurrence, a strategy targeting essential gene pathways of GSC must be identified and incorporated into the standard treatment regimen. Identifying intrinsic and extrinsic cues by which GSC maintain stemness properties and sustain both tumorigenesis and anti-apoptotic features may provide new insights into potentially curative strategies for treating brain cancers

  16. Escin Chemosensitizes Human Pancreatic Cancer Cells and Inhibits the Nuclear Factor-kappaB Signaling Pathway

    Directory of Open Access Journals (Sweden)

    A. Rimmon

    2013-01-01

    Full Text Available Background. There is an urgent need to develop new treatment strategies and drugs for pancreatic cancer that is highly resistant to radio-chemotherapy. Aesculus hippocastanum (the horse chestnut known in Chinese medicine as a plant with anti-inflammatory, antiedema, antianalgesic, and antipyretic activities. The main active compound of this plant is Escin (C54H84O23. Objective. To evaluate the effect of Escin alone and combined with chemotherapy on pancreatic cancer cell survival and to unravel mechanism(s of Escin anticancer activity. Methods. Cell survival was measured by XTT colorimetric assay. Synergistic effect of combined therapy was determined by CalcuSyn software. Cell cycle and induction of apoptosis were evaluated by FACS analysis. Expression of NF-κB-related proteins (p65, IκBα, and p-IκBα and cyclin D was evaluated by western blot analysis. Results. Escin decreased the survival of pancreatic cancer cells with IC50 = 10–20 M. Escin combined with gemcitabine showed only additive effect, while its combination with cisplatin resulted in a significant synergistic cytotoxic effect in Panc-1 cells. High concentrations of Escin induced apoptosis and decreased NF-κB-related proteins and cyclin D expression. Conclusions. Escin decreased pancreatic cancer cell survival, induced apoptosis, and downregulated NF-κB signaling pathway. Moreover, Escin sensitized pancreatic cancer cells to chemotherapy. Further translational research is required.

  17. Rare amplicons implicate frequent deregulation of cell fate specification pathways in oral squamous cell carcinoma.

    Science.gov (United States)

    Snijders, Antoine M; Schmidt, Brian L; Fridlyand, Jane; Dekker, Nusi; Pinkel, Daniel; Jordan, Richard C K; Albertson, Donna G

    2005-06-16

    Genomes of solid tumors are characterized by gains and losses of regions, which may contribute to tumorigenesis by altering gene expression. Often the aberrations are extensive, encompassing whole chromosome arms, which makes identification of candidate genes in these regions difficult. Here, we focused on narrow regions of gene amplification to facilitate identification of genetic pathways important in oral squamous cell carcinoma (SCC) development. We used array comparative genomic hybridization (array CGH) to define minimum common amplified regions and then used expression analysis to identify candidate driver genes in amplicons that spanned LAMA3, MMP7), as well as members of the hedgehog (GLI2) and notch (JAG1, RBPSUH, FJX1) pathways to be amplified and overexpressed. Deregulation of these and other members of the hedgehog and notch pathways (HHIP, SMO, DLL1, NOTCH4) implicates deregulation of developmental and differentiation pathways, cell fate misspecification, in oral SCC development. PMID:15824737

  18. 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.

  19. 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

  20. Modeling cell-cycle synchronization during embryogenesis in Xenopus laevis

    Science.gov (United States)

    McIsaac, R. Scott; Huang, K. C.; Sengupta, Anirvan; Wingreen, Ned

    2010-03-01

    A widely conserved aspect of embryogenesis is the ability to synchronize nuclear divisions post-fertilization. How is synchronization achieved? Given a typical protein diffusion constant of 10 μm^2sec, and an embryo length of 1mm, it would take diffusion many hours to propagate a signal across the embryo. Therefore, synchrony cannot be attained by diffusion alone. We hypothesize that known autocatalytic reactions of cell-cycle components make the embryo an ``active medium'' in which waves propagate much faster than diffusion, enforcing synchrony. We report on robust spatial synchronization of components of the core cell cycle circuit based on a mathematical model previously determined by in vitro experiments. In vivo, synchronized divisions are preceded by a rapid calcium wave that sweeps across the embryo. Experimental evidence supports the hypothesis that increases in transient calcium levels lead to derepression of a negative feedback loop, allowing cell divisions to start. Preliminary results indicate a novel relationship between the speed of the initial calcium wave and the ability to achieve synchronous cell divisions.

  1. (p)ppGpp and the bacterial cell cycle

    Indian Academy of Sciences (India)

    Aanisa Nazir; Rajendran Harinarayanan

    2016-06-01

    Genes of the Rel/Spo homolog (RSH) superfamily synthesize and/or hydrolyse the modified nucleotides pppGpp/ppGpp (collectively referred to as (p)ppGpp) and are prevalent across diverse bacteria and in plant chloroplasts. Bacteria accumulate (p)ppGpp in response to nutrient deprivation (generically called the stringent response) and elicit appropriate adaptive responses mainly through the regulation of transcription. Although at different concentrations (p)ppGpp affect the expression of distinct set of genes, the two well-characterized responses are reduction in expression of the protein synthesis machinery and increase in the expression of genes coding for amino acid biosynthesis. In Escherichia coli, the cellular (p)ppGpp level inversely correlates with the growth rate and increasing its concentration decreases the steady state growth rate in a defined growth medium. Since change in growth rate must be accompanied by changes in cell cycle parameters set through the activities of the DNA replication and cell division apparatus, (p)ppGpp could coordinate protein synthesis (cell mass increase) with these processes. Here we review the role of (p)ppGpp in bacterial cell cycle regulation.

  2. The Research Progress about Wnt Pathway of Lung Cancer Stem Cells

    Directory of Open Access Journals (Sweden)

    Xiaojiang LI

    2011-08-01

    Full Text Available Being the most critical signaling molecule in the Wnt pathway, the Wnt/β-catenin signaling pathway plays an important role in the maintenance of the cell proliferation and clone formation of lung cancer stem cells. Since it is closely related to the WNT pathway, the proliferation of lung cancer stem cells can be restrained by blocking the WNT pathway or influencing its key protein. Such method provides a new method for the treatment of lung cancer. By summarizing the state of-the-art research of lung cancer stem cells and the Wnt pathway from 2005 to 2010, their relationship is investigated.

  3. Wnt signaling pathway in non-small cell lung cancer.

    Science.gov (United States)

    Stewart, David J

    2014-01-01

    Wnt/β-catenin alterations are prominent in human malignancies. In non-small cell lung cancer (NSCLC), β-catenin and APC mutations are uncommon, but Wnt signaling is important in NSCLC cell lines, and Wnt inhibition reduces proliferation. Overexpression of Wnt-1, -2, -3, and -5a and of Wnt-pathway components Frizzled-8, Dishevelled, Porcupine, and TCF-4 is common in resected NSCLC and is associated with poor prognosis. Conversely, noncanonical Wnt-7a suppresses NSCLC development and is often downregulated. Although β-catenin is often expressed in NSCLCs, it was paradoxically associated with improved prognosis in some series, possibly because of E-cadherin interactions. Downregulation of Wnt inhibitors (eg, by hypermethylation) is common in NSCLC tumor cell lines and resected samples; may be associated with high stage, dedifferentiation, and poor prognosis; and has been reported for AXIN, sFRPs 1-5, WIF-1, Dkk-1, Dkk-3, HDPR1, RUNX3, APC, CDX2, DACT2, TMEM88, Chibby, NKD1, EMX2, ING4, and miR-487b. AXIN is also destabilized by tankyrases, and GSK3β may be inactivated through phosphorylation by EGFR. Preclinically, restoration of Wnt inhibitor function is associated with reduced Wnt signaling, decreased cell proliferation, and increased apoptosis. Wnt signaling may also augment resistance to cisplatin, docetaxel, and radiotherapy, and Wnt inhibitors may restore sensitivity. Overall, available data indicate that Wnt signaling substantially impacts NSCLC tumorigenesis, prognosis, and resistance to therapy, with loss of Wnt signaling inhibitors by promoter hypermethylation or other mechanisms appearing to be particularly important. Wnt pathway antagonists warrant exploration clinically in NSCLC. Agents blocking selected specific β-catenin interactions and approaches to increase expression of downregulated Wnt inhibitors may be of particular interest. PMID:24309006

  4. 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

  5. RB/PLK1-dependent induced pathway by SLAMF3 expression inhibits mitosis and control hepatocarcinoma cell proliferation

    Science.gov (United States)

    Bouhlal, Hicham; Singh, Amrathlal Rabbind; Ossart, Christèle; Reignier, Aline; Hocini, Hakim; Fouquet, Gregory; Baghami, Mohammed Al; Eugenio, Mélanie Simoes; Nguyen-Khac, Eric; Regimbeau, Jean-Marc; Marcq, Ingrid

    2016-01-01

    Polo-like kinase PLK1 is a cell cycle protein that plays multiple roles in promoting cell cycle progression. Among the many roles, the most prominent role of PLK1 is to regulate the mitotic spindle formation checkpoint at the M-phase. Recently we reported the expression of SLAMF3 in Hepatocytes and show that it is down regulated in tumor cells of hepatocellular carcinoma (HCC). We also show that the forced high expression level of SLAMF3 in HCC cells controls proliferation by inhibiting the MAPK ERK/JNK and the mTOR pathways. In the present study, we provide evidence that the inhibitory effect of SLAMF3 on HCC proliferation occurs through Retinoblastoma (RB) factor and PLK1-dependent pathway. In addition to the inhibition of MAPK ERK/JNK and the mTOR pathways, expression of SLAMF3 in HCC retains RB factor in its hypophosphorylated active form, which in turn inactivates E2F transcription factor, thereby repressing the expression and activation of PLK1. A clear inverse correlation was also observed between SLAMF3 and PLK expression in patients with HCC. In conclusion, the results presented here suggest that the tumor suppressor potential of SLAMF3 occurs through activation of RB that represses PLK1. We propose that the induction of a high expression level of SLAMF3 in cancerous cells could control cellular mitosis and block tumor progression. PMID:26799423

  6. Coupling between the Circadian Clock and Cell Cycle Oscillators: Implication for Healthy Cells and Malignant Growth

    Science.gov (United States)

    Feillet, Celine; van der Horst, Gijsbertus T. J.; Levi, Francis; Rand, David A.; Delaunay, Franck

    2015-01-01

    Uncontrolled cell proliferation is one of the key features leading to cancer. Seminal works in chronobiology have revealed that disruption of the circadian timing system in mice, either by surgical, genetic, or environmental manipulation, increased tumor development. In humans, shift work is a risk factor for cancer. Based on these observations, the link between the circadian clock and cell cycle has become intuitive. But despite identification of molecular connections between the two processes, the influence of the clock on the dynamics of the cell cycle has never been formally observed. Recently, two studies combining single live cell imaging with computational methods have shed light on robust coupling between clock and cell cycle oscillators. We recapitulate here these novel findings and integrate them with earlier results in both healthy and cancerous cells. Moreover, we propose that the cell cycle may be synchronized or slowed down through coupling with the circadian clock, which results in reduced tumor growth. More than ever, systems biology has become instrumental to understand the dynamic interaction between the circadian clock and cell cycle, which is critical in cellular coordination and for diseases such as cancer. PMID:26029155

  7. Coupling between the circadian clock and cell cycle oscillators: implication for healthy cells and malignant growth

    Directory of Open Access Journals (Sweden)

    Celine eFeillet

    2015-05-01

    Full Text Available Uncontrolled cell proliferation is one of the key features leading to cancer. Seminal works in chronobiology have revealed that disruption of the circadian timing system in mice, either by surgical, genetic or environmental manipulation, increased tumor development. In humans, shift work is a risk factor for cancer. Based on these observations, the link between the circadian clock and cell cycle has become intuitive. But despite identification of molecular connections between the two processes, the influence of the clock on the dynamics of the cell cycle has never been formally observed. Recently, two studies combining single live cell imaging with computational methods have shed light on robust coupling between clock and cell cycle oscillators. We recapitulate here these novel findings and integrate them with earlier results in both healthy and cancerous cells. Moreover, we propose that the cell cycle may be synchronized or slowed down through coupling with the circadian clock, which results in reduced tumour growth. More than ever, systems biology has become instrumental to understand the dynamic interaction between the circadian clock and cell cycle, which is critical in cellular coordination and for diseases such as cancer.

  8. 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)

  9. Curcumin induces autophagy, inhibits proliferation and invasion by downregulating AKT/mTOR signaling pathway in human melanoma cells.

    Science.gov (United States)

    Zhao, Guangming; Han, Xiaodong; Zheng, Siwen; Li, Zhen; Sha, Yang; Ni, Jing; Sun, Zhe; Qiao, Song; Song, Zhiqi

    2016-02-01

    Melanoma is the foremost malignant cutaneous cancer and it is extremely resistant to chemotherapy and radiotherapy. Curcumin is an active component of turmeric, the yellow spice derived from the rhizome of Curcuma longa, and is widely known for its anti-inflammatory and anti-cancerogenic properties. Several recent studies suggest that curcumin induces apoptosis by modulating multiple signaling pathways to exert its anticancer effect. In the present study, we investigated the effect of curcumin on the viability, invasion potential, cell cycle, autophagy and the AKT, mTOR, P70S6K proteins of AKT/mTOR signaling pathway in human melanoma A375 and C8161 cell lines in vitro and in an in vivo tumorigenesis model. Curcumin effectively inhibited the proliferation of melanoma cells in vitro and in vivo. It suppressed cell invasion, arrested the cancer cells at G2/M phase of the cell cycle, and induced autophagy. Furthermore, curcumin suppressed the activation of AKT, mTOR and P70S6K proteins. Curcumin, therefore, is a potent suppressor of cell viability and invasion, and simultaneously an inducer of autophagy in A375 and C8161 cells. Accordingly, curcumin could be a novel therapeutic candidate for the management of melanoma. PMID:26573768

  10. Prep1 (pKnox1 regulates mouse embryonic HSC cycling and self-renewal affecting the Stat1-Sca1 IFN-dependent pathway.

    Directory of Open Access Journals (Sweden)

    Livia Modica

    Full Text Available A hypomorphic Prep1 mutation results in embryonic lethality at late gestation with a pleiotropic embryonic phenotype that includes defects in all hematopoietic lineages. Reduced functionality of the hematopoietic stem cells (HSCs compartment might be responsible for the hematopoietic phenotype observed at mid-gestation. In this paper we demonstrate that Prep1 regulates the number of HSCs in fetal livers (FLs, their clonogenic potential and their ability to de novo generate the hematopoietic system in ablated hosts. Furthermore, we show that Prep1 controls the self-renewal ability of the FL HSC compartment as demonstrated by serial transplantation experiments. The premature exhaustion of Prep1 mutant HSCs correlates with the reduced quiescent stem cell pool thus suggesting that Prep1 regulates the self-renewal ability by controlling the quiescence/proliferation balance. Finally, we show that in FL HSCs Prep1 absence induces the interferon signaling pathway leading to premature cycling and exhaustion of fetal HSCs.

  11. Life-cycle fossil energy consumption and greenhouse gas emission intensity of dominant secondary energy pathways of China in 2010

    International Nuclear Information System (INIS)

    Life-cycle fossil primary energy consumption (FPEC) and greenhouse gas (GHG) emission intensity of nine types of dominant secondary energy (SE) pathways for China in 2010 are calculated with iterative methods, using the TLCAM (Tsinghua Life-cycle Analysis Model). Three major types of GHG (CO2, CH4 and N2O) are considered for GHG emission intensity, and non-combustion CH4 leakage during the feedstock production sub-stage is included. We found the following. (1) Life-cycle FPEC intensities in units of per MJ SE are obtained and used, in order of magnitude, for: raw coal (recovered only); raw natural gas (NG, recovered and processed only); raw oil (recovered and processed); final coal (finally transported to end-user); final NG (finally transported to end-user); diesel; gasoline; residual oil and electricity. (2) Although their upstream GHG emission intensities are small, their life-cycle intensities are 103.5, 68.3, 81.6, 99.3, 70.0, 101.6, 91.7, 93.5 and 226.4 g CO2,e/MJ SE, respectively, when direct GHG emissions are included. (3) Life-cycle intensities of both FPEC and GHG emissions for SE in China are higher than those in some other countries, because of the relatively low overall efficiency and high percentage of coal in the national energy mix. - Highlights: ► We calculate life-cycle energy use and GHG intensity of dominant secondary energy in China. ► Life-cycle GHG emission intensities are high and upstream intensities are low. ► The life-cycle energy and GHG intensities in China are higher than average in world

  12. BRCA1 May Modulate Neuronal Cell Cycle Re-Entry in Alzheimer Disease

    OpenAIRE

    Evans, Teresa A.; Raina, Arun K; Delacourte, André; Aprelikova, Olga; Lee, Hyoung-gon; Zhu, Xiongwei; Perry, George; Smith, Mark A.

    2007-01-01

    In Alzheimer disease, neuronal degeneration and the presence of neurofibrillary tangles correlate with the severity of cognitive decline. Neurofibrillary tangles contain the antigenic profile of many cell cycle markers, reflecting a re-entry into the cell cycle by affected neurons. However, while such a cell cycle re-entry phenotype is an early and consistent feature of Alzheimer disease, the mechanisms responsible for neuronal cell cycle are unclear. In this regard, given that a dysregulated...

  13. Cell Cycle Regulating Kinase Cdk4 as a Potential Target for Tumor Cell Treatment and Tumor Imaging

    Directory of Open Access Journals (Sweden)

    Franziska Graf

    2009-01-01

    Full Text Available The cyclin-dependent kinase (Cdk-cyclin D/retinoblastoma (pRb/E2F cascade, which controls the G1/S transition of cell cycle, has been found to be altered in many neoplasias. Inhibition of this pathway by using, for example, selective Cdk4 inhibitors has been suggested to be a promising approach for cancer therapy. We hypothesized that appropriately radiolabeled Cdk4 inhibitors are suitable probes for tumor imaging and may be helpful studying cell proliferation processes in vivo by positron emission tomography. Herein, we report the synthesis and biological, biochemical, and radiopharmacological characterizations of two I124-labeled small molecule Cdk4 inhibitors (8-cyclopentyl-6-iodo-5-methyl-2-(4-piperazin-1-yl-phenylamino-8H-pyrido[2,3-d]-pyrimidin-7-one (CKIA and 8-cyclopentyl-6-iodo-5-methyl-2-(5-(piperazin-1-yl-pyridin-2-yl-amino-8H-pyrido[2,3-d]pyrimidin-7-one (CKIB. Our data demonstrate a defined and specific inhibition of tumor cell proliferation through CKIA and CKIB by inhibition of the Cdk4/pRb/E2F pathway emphasizing potential therapeutic benefit of CKIA and CKIB. Furthermore, radiopharmacological properties of [I124]CKIA and [I124]CKIB observed in human tumor cells are promising prerequisites for in vivo biodistribution and imaging studies.

  14. Wnt inhibitory factor-1 regulates glioblastoma cell cycle and proliferation.

    Science.gov (United States)

    Wu, Jun; Fang, Jiasheng; Yang, Zhuanyi; Chen, Fenghua; Liu, Jingfang; Wang, Yanjin

    2012-10-01

    Wnt proteins are powerful regulators of cell proliferation and differentiation, and activation of the Wnt signalling pathway is involved in the pathogenesis of several types of human tumours. Wnt inhibitory factor-1 (WIF-1) acts as a Wnt antagonist and tumour suppressor. Previous studies have shown that reducing expression of the WIF-1 gene aberrantly activates Wnt signalling and induces the development of certain types of cancers. In the present study, we examined the expression of WIF-1 in human primary glioblastoma multiforme (GBM) tumours. Studies using semiquantitative reverse transcription-polymerase chain reaction and immunohistochemical analysis revealed that WIF-1 expression is lower in human GBM than in normal brain tissue. To clarify the role of WIF-1, we transfected U251 human glioblastoma-derived cells, which do not express WIF-1, with the pcDNA3.1-WIF1 vector to restore WIF-1 expression. The results of cell proliferation, colony formation and apoptosis assays, as well as flow cytometry, indicate that exogenous WIF-1 has no effect on U251 cell apoptosis, but does arrest cells at the G(0)/G(1) phase and inhibit cell growth. Collectively, our data suggest that WIF-1 is a potent inhibitor of GBM growth. PMID:22901505

  15. MAML1 regulates cell viability via the NF-{kappa}B pathway in cervical cancer cell lines

    Energy Technology Data Exchange (ETDEWEB)

    Kuncharin, Yanin [Medical Microbiology Interdisciplinary Program, Graduate School, Chulalongkorn University, Payathai Road, Pathumwan, Bangkok 10330 (Thailand); Sangphech, Naunpun [Biotechnology Program, Faculty of Science, Chulalongkorn University, Payathai Road, Pathumwan, Bangkok 10330 (Thailand); Kueanjinda, Patipark [Medical Microbiology Interdisciplinary Program, Graduate School, Chulalongkorn University, Payathai Road, Pathumwan, Bangkok 10330 (Thailand); Bhattarakosol, Parvapan [Medical Microbiology Interdisciplinary Program, Graduate School, Chulalongkorn University, Payathai Road, Pathumwan, Bangkok 10330 (Thailand); Department of Microbiology, Faculty of Medicine, Chulalongkorn University, Payathai Road, Pathumwan, Bangkok 10330 (Thailand); Palaga, Tanapat, E-mail: tanapat.p@chula.ac.th [Department of Microbiology, Faculty of Science, Chulalongkorn University, Payathai Road, Pathumwan, Bangkok 10330 (Thailand)

    2011-08-01

    The Notch signaling pathway plays important roles in tumorigenesis in a context-dependent manner. In human cervical cancer, alterations in Notch signaling have been reported, and both tumor-suppressing and tumor-promoting roles of Notch signaling have been proposed; however, the precise molecular mechanisms governing these roles in cervical cancer remain controversial. MAML is a transcriptional co-activator originally identified by its role in Notch signaling. Recent evidence suggests that it also plays a role in other signaling pathways, such as the p53 and {beta}-catenin pathways. MAML is required for stable formation of Notch transcriptional complexes at the promoters of Notch target genes. Chromosomal translocations affecting MAML have been shown to promote tumorigenesis. In this study, we used a truncated dominant-negative MAML1 (DN-MAML) to investigate the role of MAML in HPV-positive cervical cancer cell lines. Three human cervical cancer cell lines (HeLa, SiHa and CaSki) expressed all Notch receptors and the Notch target genes Hes1 and MAML1. Among these 3 cell lines, constitutive appearance of cleaved Notch1 was found only in CaSki cells, which suggests that Notch1 is constitutively activated in this cell line. Gamma secretase inhibitor (GSI) treatment, which suppresses Notch receptor activation, completely abrogated this form of Notch1 but had no effect on cell viability. Overexpression of DN-MAML by retroviral transduction in CaSki cells resulted in significant decreases in the mRNA levels of Hes1 and Notch1 but had no effects on the levels of MAML1, p53 or HPV E6/E7. DN-MAML expression induced increased viability of CaSki cells without any effect on cell cycle progression or cell proliferation. In addition, clonogenic assay experiments revealed that overexpression of DN-MAML resulted in increased colony formation compared to the overexpression of the control vector. When the status of the NF-{kappa}B pathway was investigated, CaSki cells overexpressing

  16. Real-time observation of irradiated Hela-cell Modified by Fluorescent ubiquitination-based Cell Cycle Indicator Using Synchrotron X-Ray Microbeam

    International Nuclear Information System (INIS)

    Fluorescent ubiquitination-based cell-cycle indicator (FUCCI) human cancer (HeLa) cells (red indicates G1; green, S/G2) were exposed to a synchrotron X-ray microbeam. Cells in either G1 or S/G2 were irradiated selectively according to their colour in the same microscopic field. Time-lapse micrographs of the irradiated cells were acquired for 24 h after irradiation. For fluorescent immunostaining, phosphorylated histone proteins (γ-H2AX) indicated the induction of DNA double-strand breaks. The cell cycle was arrested by irradiation at S/G2. In contrast, cells irradiated at G1 progressed to S/G2. The foci were induced in cells irradiated at both G1 and S/G2, suggesting that the G1-S (or S) checkpoint pathway does not function in HeLa cells due to the fact that the cells are functionally p53 deficient, even though X-ray microbeam irradiation significantly induces double-strand breaks. These results demonstrate that single FUCCI cell exposure and live cell imaging are powerful methods for studying the effects of radiation on the cell cycle. (authors)

  17. Cytokine-dependent and–independent gene expression changes and cell cycle block revealed in Trypanosoma cruzi-infected host cells by comparative mRNA profiling

    Directory of Open Access Journals (Sweden)

    Burleigh Barbara A

    2009-05-01

    Full Text Available Abstract Background The requirements for growth and survival of the intracellular pathogen Trypanosoma cruzi within mammalian host cells are poorly understood. Transcriptional profiling of the host cell response to infection serves as a rapid read-out for perturbation of host physiology that, in part, reflects adaptation to the infective process. Using Affymetrix oligonucleotide array analysis we identified common and disparate host cell responses triggered by T. cruzi infection of phenotypically diverse human cell types. Results We report significant changes in transcript abundance in T. cruzi-infected fibroblasts, endothelial cells and smooth muscle cells (2852, 2155 and 531 genes respectively; fold-change ≥ 2, p-value T. cruzi-infected fibroblasts and endothelial cells transwell plates were used to distinguish cytokine-dependent and -independent gene expression profiles. This approach revealed the induction of metabolic and signaling pathways involved in cell proliferation, amino acid catabolism and response to wounding as common themes in T. cruzi-infected cells. In addition, the downregulation of genes involved in mitotic cell cycle and cell division predicted that T. cruzi infection may impede host cell cycle progression. The observation of impaired cytokinesis in T. cruzi-infected cells, following nuclear replication, confirmed this prediction. Conclusion Metabolic pathways and cellular processes were identified as significantly altered at the transcriptional level in response to T. cruzi infection in a cytokine-independent manner. Several of these alterations are supported by previous studies of T. cruzi metabolic requirements or effects on the host. However, our methods also revealed a T. cruzi-dependent block in the host cell cycle, at the level of cytokinesis, previously unrecognized for this pathogen-host cell interaction.

  18. IL-7 splicing variant IL-7{delta}5 induces human breast cancer cell proliferation via activation of PI3K/Akt pathway

    Energy Technology Data Exchange (ETDEWEB)

    Pan, Deshun [Guangdong Key Laboratory of Pharmaceutical Bioactive Substances, Guangdong Pharmaceutical University, Guangzhou, Guangdong 510006 (China); Department of Pharmaceutical science, Guangdong Pharmaceutical University, Guangzhou, Guangdong (China); Liu, Bing [Department of Pharmaceutical science, Guangdong Pharmaceutical University, Guangzhou, Guangdong (China); Jin, Xiaobao [Guangdong Key Laboratory of Pharmaceutical Bioactive Substances, Guangdong Pharmaceutical University, Guangzhou, Guangdong 510006 (China); Zhu, Jiayong, E-mail: zhujiayong888@163.com [Guangdong Key Laboratory of Pharmaceutical Bioactive Substances, Guangdong Pharmaceutical University, Guangzhou, Guangdong 510006 (China)

    2012-06-15

    Highlights: Black-Right-Pointing-Pointer This study confirms the role of IL-7{delta}5 in breast cancer cell proliferation. Black-Right-Pointing-Pointer IL-7{delta}5 promotes breast cancer cell proliferation and cell cycle progression. Black-Right-Pointing-Pointer IL-7{delta}5 promotes cell proliferation via activation of PI3K/Akt pathway. -- Abstract: Various tumor cells express interleukin 7 (IL-7) and IL-7 variants. IL-7 has been confirmed to stimulate solid tumor cell proliferation. However, the effect of IL-7 variants on tumor cell proliferation remains unclear. In this study, we evaluated the role of IL-7{delta}5 (an IL-7 variant lacking exon 5) on proliferation and cell cycle progression of human MDA-MB-231 and MCF-7 breast cancer cells. The results showed that IL-7{delta}5 promoted cell proliferation and cell cycle progression from G1 phase to G2/M phase, associated with upregulation of cyclin D1 expression and the downregulation of p27{sup kip1} expression. Mechanistically, we found that IL-7{delta}5 induced the activation of Akt. Inhibition of PI3K/Akt pathway by LY294002 reversed the proliferation and cell cycle progression of MDA-MB-231 and MCF-7 cells induced by IL-7{delta}5. In conclusion, our findings demonstrate that IL-7{delta}5 variant induces human breast cancer cell proliferation and cell cycle progression via activation of PI3K/Akt pathway. Thus, IL-7{delta}5 may be a potential target for human breast cancer therapeutics intervention.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2010-07-16

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

  20. Examining and elucidation of human weight cycle model adopting e-cell simulation system.

    Science.gov (United States)

    Rajesh, Durairaj; Muthukumar, Subramanian; Siva, Durairaj; Saibaba, Ganesan; Dhanasekaran, Dharumadhurai; Archunan, Govindaraju

    2015-01-01

    Cellular rhythms regulate various physiological functions in circadian oscillatory mechanisms. Weight cycling or 'yo-yo' dieting is an evitable process in human, because of subsequent loss and regain of body weight due to irregular diet. Human weight cycle (HWC) is the major factor for causing global epidemic diseases in human beings. Understanding the HWC process would provide potent additional knowledge to prevent obesity. However till date, there is no study dealing with examine the HWC model using virtual cell simulation based on system biological approach. Therefore, the present study was designed to develop a computational HWC model, which was simulated using E-cell system v3.0. The developed model has the cyclic feedback reactions of three significant variables (the consecutive cycles of weight loss in continuous food intake (Q) and regain of body weight (P) at highest threshold point of cognitive restraint (R)) which are obtained by mathematical modelling. The dynamic plot results supported that the PQR variables depicted sustained oscillation with reversible modification due to protein diet. By contrast, the virtual model simulation would provide extensive information on HWC, which might provide knowledge to develop HWC linked with obesity pathway. The presents study concludes that optimization of body weight is essential to prevent the obesity based diseases. PMID:26339149

  1. Genome-wide screen identifies novel machineries required for both ciliogenesis and cell cycle arrest upon serum starvation.

    Science.gov (United States)

    Kim, Ji Hyun; Ki, Soo Mi; Joung, Je-Gun; Scott, Eric; Heynen-Genel, Susanne; Aza-Blanc, Pedro; Kwon, Chang Hyuk; Kim, Joon; Gleeson, Joseph G; Lee, Ji Eun

    2016-06-01

    Biogenesis of the primary cilium, a cellular organelle mediating various signaling pathways, is generally coordinated with cell cycle exit/re-entry. Although the dynamic cell cycle-associated profile of the primary cilium has been largely accepted, the mechanism governing the link between ciliogenesis and cell cycle progression has been poorly understood. Using a human genome-wide RNAi screen, we identify genes encoding subunits of the spliceosome and proteasome as novel regulators of ciliogenesis. We demonstrate that 1) the mRNA processing-related hits are essential for RNA expression of molecules acting in cilia disassembly, such as AURKA and PLK1, and 2) the ubiquitin-proteasome systems (UPS)-involved hits are necessary for proteolysis of molecules acting in cilia assembly, such as IFT88 and CPAP. In particular, we show that these screen hit-associated mechanisms are crucial for both cilia assembly and cell cycle arrest in response to serum withdrawal. Finally, our data suggest that the mRNA processing mechanism may modulate the UPS-dependent decay of cilia assembly regulators to control ciliary resorption-coupled cell cycle re-entry. PMID:27033521

  2. Secretory pathways in animal cells: with emphasis on pancreatic acinar cells.

    Science.gov (United States)

    Beaudoin, A R; Grondin, G

    1991-01-01

    Studies over the past three decades have clearly established the existence of at least two distinct pathways for the intracellular transport and release of secretory proteins by animal cells. These have been identified as the regulated and constitutive pathways. Many observations have indicated that in certain cells, such as those of the exocrine pancreas and parotid glands at least, these pathways coexist in the same cells. Although the general scheme of protein transport within these pathways is well established, many fundamental aspects of intracellular transport remain to be unraveled. How are proteins transported through the endoplasmic reticulum? How are the transitional vesicles formed and what are the underlying mechanisms involved in their fusion with the cis-Golgi cisterna? Even the general mode of transfer through the Golgi stack is debated: Is there a diffusion through the stack by flow through intercisternal tubules and openings or is there a vesicle transfer system where membrane quanta hop from one cisterna to the other? What is the fate of secretory proteins in the trans-Golgi area and by what mechanisms is a fraction of newly synthesized molecules of a given secretory protein released spontaneously while the majority of such nascent molecules are diverted into a secretory granule compartment? In this review, we have examined these and other aspects of intracellular transport of secretory proteins using pancreatic acinar cells as our reference model and we present some evidence to support the existence of a paragranular pathway of secretion associated with secretory granule maturation. PMID:1993938

  3. High content cell-based assay for the inflammatory pathway

    Science.gov (United States)

    Mukherjee, Abhishek; Song, Joon Myong

    2015-07-01

    Cellular inflammation is a non-specific immune response to tissue injury that takes place via cytokine network orchestration to maintain normal tissue homeostasis. However chronic inflammation that lasts for a longer period, plays the key role in human diseases like neurodegenerative disorders and cancer development. Understanding the cellular and molecular mechanisms underlying the inflammatory pathways may be effective in targeting and modulating their outcome. Tumor necrosis factor alpha (TNF-α) is a pro-inflammatory cytokine that effectively combines the pro-inflammatory features with the pro-apoptotic potential. Increased levels of TNF-α observed during acute and chronic inflammatory conditions are believed to induce adverse phenotypes like glucose intolerance and abnormal lipid profile. Natural products e. g., amygdalin, cinnamic acid, jasmonic acid and aspirin have proven efficacy in minimizing the TNF-α induced inflammation in vitro and in vivo. Cell lysis-free quantum dot (QDot) imaging is an emerging technique to identify the cellular mediators of a signaling cascade with a single assay in one run. In comparison to organic fluorophores, the inorganic QDots are bright, resistant to photobleaching and possess tunable optical properties that make them suitable for long term and multicolor imaging of various components in a cellular crosstalk. Hence we tested some components of the mitogen activated protein kinase (MAPK) pathway during TNF-α induced inflammation and the effects of aspirin in HepG2 cells by QDot multicolor imaging technique. Results demonstrated that aspirin showed significant protective effects against TNF-α induced cellular inflammation. The developed cell based assay paves the platform for the analysis of cellular components in a smooth and reliable way.

  4. Andrographolide suppresses epithelial mesenchymal transition by inhibition of MAPK signalling pathway in lens epithelial cells

    Indian Academy of Sciences (India)

    Forum Kayastha; Kaid Johar; Devarshi Gajjar; Anshul Arora; Hardik Madhu; Darshini Ganatra; Abhay Vasavada

    2015-06-01

    Epithelial mesenchymal transition (EMT) of lens epithelial cells (LECs) may contribute to the development of posterior capsular opacification (PCO), which leads to visual impairment. Andrographolide has been shown to have therapeutic potential against various cancers. However, its effect on human LECs is still unknown. The purpose of this study is to evaluate the effect of andrographolide on EMT induced by growth factors in the fetal human lens epithelial cell line (FHL 124). Initially the LECs were treated with growth factors (TGF-2 and bFGF) to induce EMT. Subsequently these EMT-induced cells were treated with andrographolide at 100 and 500 nM concentrations for 24 h. Our results showed that FHL 124 cells treated with growth factors had a significant decrease in protein and m-RNA levels of epithelial markers pax6 and E-Cadherin. After administering andrographolide, these levels significantly increased. It was noticed that EMT markers -SMA, fibronectin and collagen IV significantly decreased after treatment with andrographolide when compared to the other group. Treatment with andrographolide significantly inhibited phosphorylation of ERK and JNK. Cell cycle analysis showed that andrographolide did not arrest cells at G0/G1 or G2/M at tested concentrations. Our findings suggest that andrographolide helps sustain epithelial characteristics by modulating EMT markers and inhibiting the mitogen-activated protein kinase (MAPK) signalling pathway in LECs. Hence it can prove to be useful in curbing EMT-mediated PCO.

  5. Andrographolide suppresses epithelial mesenchymal transition by inhibition of MAPK signalling pathway in lens epithelial cells.

    Science.gov (United States)

    Kayastha, Forum; Johar, Kaid; Gajjar, Devarshi; Arora, Anshul; Madhu, Hardik; Ganatra, Darshini; Vasavada, Abhay

    2015-06-01

    Epithelial mesenchymal transition (EMT) of lens epithelial cells (LECs) may contribute to the development of posterior capsular opacification (PCO), which leads to visual impairment. Andrographolide has been shown to have therapeutic potential against various cancers. However, its effect on human LECs is still unknown. The purpose of this study is to evaluate the effect of andrographolide on EMT induced by growth factors in the fetal human lens epithelial cell line (FHL 124). Initially the LECs were treated with growth factors (TGF-beta 2 and bFGF) to induce EMT. Subsequently these EMT-induced cells were treated with andrographolide at 100 and 500 nM concentrations for 24 h. Our results showed that FHL 124 cells treated with growth factors had a significant decrease in protein and m-RNA levels of epithelial markers pax6 and E-Cadherin. After administering andrographolide, these levels significantly increased. It was noticed that EMT markers alpha-SMA, fibronectin and collagen IV significantly decreased after treatment with andrographolide when compared to the other group. Treatment with andrographolide significantly inhibited phosphorylation of ERK and JNK. Cell cycle analysis showed that andrographolide did not arrest cells at G0/G1 or G2/M at tested concentrations. Our findings suggest that andrographolide helps sustain epithelial characteristics by modulating EMT markers and inhibiting the mitogen-activated protein kinase (MAPK) signalling pathway in LECs. Hence it can prove to be useful in curbing EMT-mediated PCO. PMID:25963259

  6. Inhibitory effect of ubiquitin-proteasome pathway on proliferation of esophageal carcinoma cells

    Institute of Scientific and Technical Information of China (English)

    Wei-Guo Zhang; Jie-Ping Yu; Qing-Ming Wu; Qiang Tong; Sheng-Bao Li; Xiao-Hu Wang; Guo-Jian Xie

    2004-01-01

    AIM: To investigate the inhibitory effect of ubiquitinproteasome pathway (UPP) on proliferation of esophageal carcinoma cells.METHODS: Esophageal carcinoma cell strain EC9706 was treated with MG-132 to inhibit its UPP specificity. Cell growth suppression was evaluated with 3-(4,5-dimethylthiazole2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay. DNA synthesis was evaluated by 3H-thymidine (3H-TdR)incorporation. Morphologic changes of cells were observed under microscope. Activity of telomerase was examined by telomeric repeat amplification protocol (TRAP) of PCRELISA. Cell cycle and apoptosis were detected by flow cytometry (FCM). DNA fragment analysis was used to confirm the presence of apoptosis. Expression of p27kip1was detected by immunocytochemical technique.RESULTS: After exposed to MG-132, the growth and value of 3H-TdR incorporation of EC9706 cells were obviously inhibited. Cells became round, small and exfoliative under microscope. TRAP PCR-ELISA showed that light absorption of cells gradually decreased after exposed to 5 μmol/L of MG-132 for 24, 48, 72 and 96 h (P<0.01). The percentage of cells at G0/G1 phase was increased and that at S and G2/M was decreased (P<0.01). The rate of apoptotic cells treated with 5 μmol/L of MG-132 for 48 and 96 h was 31.7%and 66.4%, respectively. Agarose electrophoresis showed marked ladders. In addition, the positive signals of p27kip1were located in cytoplasm and nuclei in MG-132 group in contrast to cytoplasm staining in control group.CONCLUSION: MG-132 can obviously inhibit proliferation of EC9706 cells and induce apoptosis. The mechanisms include upregulation of p27kip1 expression, G1 arrest and depression of telomerase activity. The results indicate that inhibiting UPP is a novel strategy for esophageal carcinoma therapy.

  7. Integrative analysis of cell cycle control in budding yeast.

    Science.gov (United States)

    Chen, Katherine C; Calzone, Laurence; Csikasz-Nagy, Attila; Cross, Frederick R; Novak, Bela; Tyson, John J

    2004-08-01

    The adaptive responses of a living cell to internal and external signals are controlled by networks of proteins whose interactions are so complex that the functional integration of the network cannot be comprehended by intuitive reasoning alone. Mathematical modeling, based on biochemical rate equations, provides a rigorous and reliable tool for unraveling the complexities of molecular regulatory networks. The budding yeast cell cycle is a challenging test case for this approach, because the control system is known in exquisite detail and its function is constrained by the phenotypic properties of >100 genetically engineered strains. We show that a mathematical model built on a consensus picture of this control system is largely successful in explaining the phenotypes of mutants described so far. A few inconsistencies between the model and experiments indicate aspects of the mechanism that require revision. In addition, the model allows one to frame and critique hypotheses about how the division cycle is regulated in wild-type and mutant cells, to predict the phenotypes of new mutant combinations, and to estimate the effective values of biochemical rate constants that are difficult to measure directly in vivo. PMID:15169868

  8. Gene Expression Profiling Identifies Cell Proliferation and Inflammation as the Predominant Pathways Regulated by Aryl Hydrocarbon Receptor in Primary Human Fetal Lung Cells Exposed to Hyperoxia.

    Science.gov (United States)

    Shivanna, Binoy; Maity, Suman; Zhang, Shaojie; Patel, Ananddeep; Jiang, Weiwu; Wang, Lihua; Welty, Stephen E; Belmont, John; Coarfa, Cristian; Moorthy, Bhagavatula

    2016-07-01

    Exposure to hyperoxia contributes to the development of bronchopulmonary dysplasia (BPD) in premature infants. We observed that aryl hydrocarbon receptor (AhR) signaling protects newborn mice and primary fetal human pulmonary microvascular endothelial cells (HPMECs) against hyperoxic injury. Additionally, a recent genome-wide transcriptome study in a newborn mouse model of BPD identified AhR as a key regulator of hyperoxia-induced gene dysregulation. Whether the AhR similarly deregulates genes in HPMEC is unknown. Therefore, the objective of this study was to characterize transcriptome level gene expression profile in AhR-sufficient and -deficient HPMEC exposed to normoxic and hyperoxic conditions. Global gene expression profiling was performed using Illumina microarray platform and selected genes were validated by real-time RT-PCR. AhR gene expression and hyperoxia independently affected the expression of 540 and 593 genes, respectively. Two-way ANOVA further identified 85 genes that were affected by an interaction between AhR expression and exposure to hyperoxia. Kyoto Encyclopedia of Genes and Genomes (KEGG), Gene Ontology, and Reactome pathway analysis identified cell proliferation, immune function, cytokine signaling, and organ development as the major pathways affected in AhR-deficient cells. The biological processes that were significantly enriched by hyperoxia included metabolic process, stress response, signal transduction, cell cycle, and immune regulation. Cell cycle was the predominant pathway affected by the combined effect of AhR knockdown and hyperoxia. Functional analysis of cell cycle showed that AhR-deficient cells had decreased proliferation compared with AhR-sufficient cells. These findings suggest that AhR modulates hyperoxic lung injury by regulating the genes that are necessary for cell proliferation and inflammation. PMID:27103661

  9. Impaired Cell Cycle Regulation in a Natural Equine Model of Asthma.

    Directory of Open Access Journals (Sweden)

    Alicja Pacholewska

    Full Text Available Recurrent airway obstruction (RAO is a common and potentially debilitating lower airway disease in horses, which shares many similarities with human asthma. In susceptible horses RAO exacerbation is caused by environmental allergens and irritants present in hay dust. The objective of this study was the identification of genes and pathways involved in the pathology of RAO by global transcriptome analyses in stimulated peripheral blood mononuclear cells (PBMCs. We performed RNA-seq on PBMCs derived from 40 RAO affected and 45 control horses belonging to three cohorts of Warmblood horses: two half-sib families and one group of unrelated horses. PBMCs were stimulated with hay dust extract, lipopolysaccharides, a recombinant parasite antigen, or left unstimulated. The total dataset consisted of 561 individual samples. We detected significant differences in the expression profiles between RAO and control horses. Differential expression (DE was most marked upon stimulation with hay dust extract. An important novel finding was a strong upregulation of CXCL13 together with many genes involved in cell cycle regulation in stimulated samples from RAO affected horses, in addition to changes in the expression of several HIF-1 transcription factor target genes. The RAO condition alters systemic changes observed as differential expression profiles of PBMCs. Those changes also depended on the cohort and stimulation of the samples and were dominated by genes involved in immune cell trafficking, development, and cell cycle regulation. Our findings indicate an important role of CXCL13, likely macrophage or Th17 derived, and the cell cycle regulator CDC20 in the immune response in RAO.

  10. Coupling of the cell cycle and apoptotic machineries in developing T cells.

    Science.gov (United States)

    Xue, Ling; Sun, Yuefang; Chiang, Leslie; He, Bo; Kang, Chulho; Nolla, Hector; Winoto, Astar

    2010-03-01

    Proliferation and apoptosis are diametrically opposite processes. Expression of certain genes like c-Myc, however, can induce both, pointing to a possible linkage between them. Developing CD4(+)CD8(+) thymocytes are intrinsically sensitive to apoptosis, but the molecular basis is not known. We have found that these noncycling cells surprisingly express many cell cycle proteins. We generated transgenic mice expressing a CDK2 kinase-dead (CDK2-DN) protein in the T cell compartment. Analysis of these mice showed that the CDK2-DN protein acts as a dominant negative mutant in mature T cells as expected, but surprisingly, it acts as a dominant active protein in CD4(+)CD8(+) thymocytes. The levels of CDK2 kinase activity, cyclin E, cyclin A, and other cell cycle proteins in transgenic CD4(+)CD8(+) thymocytes are increased. Concurrently, caspase levels are elevated, and apoptosis is significantly enhanced in vitro and in vivo. E2F-1, the unique E2F member capable of inducing apoptosis when overexpressed, is specifically up-regulated in transgenic CD4(+)CD8(+) thymocytes but not in other T cell populations. These results demonstrate that the cell cycle and apoptotic machineries are normally linked, and expression of cell cycle proteins in developing T cells contributes to their inherent 1sensitivity to apoptosis. PMID:20068041

  11. 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

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

    Energy Technology Data Exchange (ETDEWEB)

    FuelCell Energy

    2005-05-16

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

  13. Regulation of the G1 phase of the mammalian cell cycle

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    In any multi-cellular organism, the balance between cell division and cell death maintains a constant cell num ber. Both cell division cycle and cell death are highly regulated events. Whether the cell will proceed through the cycle or not, depends upon whether the conditions re quired at the checkpoints during the cycle are filfilled. In higher eucaryotic cells, such as mammalian cells, signals that arrest the cycle usually act at a G1 checkpoint. Cells that pass this restriction point are committed to complete the cycle. Regulation of the G1 phase of the cell cycle is extremely complex and involves many different families of proteins such as retinoblastoma family, cyclin dependent kinases, cyclins, and cyclin kinase inhibitors.

  14. Analysis of X-ray induced cell-cycle perturbations in mouse osteosarcoma cells: a two-signal cell-cycle model

    International Nuclear Information System (INIS)

    The effects of X-irradiation on mouse osteosarcoma cells have been studied by time-lapse cinematography and the resulting pedigrees have been analysed statistically. It is shown that the irradiation treatment causes three types of cell kinetic lesions: cell death (disintegration), cell sterilization (failure to divide) and proliferation delay. The first two lesions are the most important with regard to survival of the irradiated cell in a clonal assay. Of these two lesions, sterilization appears to be highly correlated for sister cells, while this is not true for cell disintegration. This indicates that cell survival in a clonal assay may be a function of the ratio of the incidences of these two types of lesions. The X-ray-induced proliferation delay was studied in terms of intermitotic time distributions, mother-daughter correlation and sibling correlation in relation to the current cell-cycle phase at the time of treatment. This analysis shows that the effects of irradiation on these cell-cycle characteristics is highly cell-cycle-dependent. A qualitative model to account for the observations is presented. (author)

  15. Differential regulation of intracellular factors mediating cell cycle, DNA repair and inflammation following exposure to silver nanoparticles in human cells

    Directory of Open Access Journals (Sweden)

    AshaRani PV

    2012-02-01

    Full Text Available Abstract Background Investigating the cellular and molecular signatures in eukaryotic cells following exposure to nanoparticles will further our understanding on the mechanisms mediating nanoparticle induced effects. This study illustrates the molecular effects of silver nanoparticles (Ag-np in normal human lung cells, IMR-90 and human brain cancer cells, U251 with emphasis on gene expression, induction of inflammatory mediators and the interaction of Ag-np with cytosolic proteins. Results We report that silver nanoparticles are capable of adsorbing cytosolic proteins on their surface that may influence the function of intracellular factors. Gene and protein expression profiles of Ag-np exposed cells revealed up regulation of many DNA damage response genes such as Gadd 45 in both the cell types and ATR in cancer cells. Moreover, down regulation of genes necessary for cell cycle progression (cyclin B and cyclin E and DNA damage response/repair (XRCC1 and 3, FEN1, RAD51C, RPA1 was observed in both the cell lines. Double strand DNA damage was observed in a dose dependant manner as evidenced in γH2AX foci assay. There was a down regulation of p53 and PCNA in treated cells. Cancer cells in particular showed a concentration dependant increase in phosphorylated p53 accompanied by the cleavage of caspase 3 and PARP. Our results demonstrate the involvement of NFκB and MAP kinase pathway in response to Ag-np exposure. Up regulation of pro-inflammatory cytokines such as interleukins (IL-8, IL-6, macrophage colony stimulating factor, macrophage inflammatory protein in fibroblasts following Ag-np exposure were also observed. Conclusion In summary, Ag-np can modulate gene expression and protein functions in IMR-90 cells and U251 cells, leading to defective DNA repair, proliferation arrest and inflammatory response. The observed changes could also be due to its capability to adsorb cytosolic proteins on its surface.

  16. 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.

  17. 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.

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

    Science.gov (United States)

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

    2014-01-01

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

  19. RNA interference-mediated silencing of NANOG reduces cell proliferation and induces G0/G1 cell cycle arrest in breast cancer cells.

    Science.gov (United States)

    Han, Jinghua; Zhang, Fei; Yu, Man; Zhao, Peiqi; Ji, Wei; Zhang, Haichang; Wu, Bing; Wang, Yuqing; Niu, Ruifang

    2012-08-01

    Since the processes of normal embryogenesis and neoplasia share many of similar pathways, tumor development has been interpreted as an abnormal form of organogenesis. NANOG is a homeodomain-containing transcription factor that functions to maintain self-renewal and proliferation of embryonic stem cells (ESCs). Aberrant expression of NANOG has been observed in many types of human malignancies. However, its potential implication in tumorigenesis has not been fully clarified. In this study, we have employed small interference RNA (RNAi) technology to silence endogenous NANOG expression in breast cancer cells and successfully selected three independent clones with stably inhibited NANOG expression of MCF-7 cells. Functional analysis revealed that down-regulation of NANOG reduced cell proliferation, colony formation and migration ability of MCF-7 cells. Consistently, proliferation of breast cancer MDA-MB-231 cells was also significantly inhibited after the knockdown of NANOG expression. Interestingly, we found that the expression levels of cyclinD1 and c-myc were markedly down-regulated and the cell cycle were blocked at the G0/G1 phases after the knockdown of NANOG, while the expression of cyclinE and signal transducers and activators of transcription3 (STAT3) remained unaffected. In addition, the expression of NANOG and cyclinD1 can be rescued after the transfection of pcDNA3.1 (-)-NANOG expression vector into the three clones. Finally, our chromatin immunoprecipitation (ChIP) experiment showed that NANOG protein can bind to the promoter region of cyclinD1 and regulate cells cycle. Taken together, our findings may not only establish a molecular basis for the role of NANOG in modulating cell cycle progression of breast cancer cells but also suggest a potential target for the treatment of at least some subtypes of breast cancer. PMID:22381696

  20. Asthma and influenza virus infection:focusing on cell death and stress pathways in influenza virus replication.

    Directory of Open Access Journals (Sweden)

    Behzad Yeganeh

    2013-03-01

    Full Text Available Asthma is one of the fastest growing syndromes in many countries and is adding a huge cost to the health care system. Increasing reports have linked airway infectious diseases to asthma. Influenza is one of the most serious airway infectious diseases and in recent years there have been some serious influenza virus pandemics which caused increased fatality in numerous different populations. Diverse host response pathways during virus infection have been identified, including different cell death and survival pathways. These pathways include1 programmed cell death I (apoptosis, 2 programmed cell death II (autophagy, and 3 endoplasmic reticulum stress with subsequent unfolded protein response (UPR. There has been extensive research on the regulatory roles of these pathways during the influenza virus life cycle. These studies address the benefits of enhancing or inhibiting these pathways on viral replication. Here we review the most recent and significant knowledge in this area for possible  benefits  to  clinicians and  basic  scientist researchers  in  different  areas  of  the respiratory and virology sciences.

  1. 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

  2. Selaginellatamariscina attenuates metastasis via Akt pathways in oral cancer cells.

    Directory of Open Access Journals (Sweden)

    Jia-Sin Yang

    Full Text Available BACKGROUND: Crude extracts of Selaginellatamariscina, an oriental medicinal herb, have been evidenced to treat several human diseases. This study investigated the mechanisms by which Selaginellatamariscina inhibits the invasiveness of human oral squamous-cell carcinoma (OSCC HSC-3 cells. METHODOLOGY/PRINCIPAL FINDINGS: Herein, we demonstrate that Selaginellatamariscina attenuated HSC-3 cell migration and invasion in a dose-dependent manner. The anti-metastatic activities of Selaginellatamariscina occurred at least partially because of the down-regulation of matrix metalloproteinases (MMP-2 and MMP-9 gelatinase activity and the down-regulation of protein expression. The expression and function of both MMP-2 and MMP-9 were regulated by Selaginellatamariscina at a transcriptional level, as shown by quantitative real-time PCR and reporter assays. Chromatin immunoprecipitation (ChIP data further indicated that binding of the cAMP response element-binding (CREB protein and activating protein-1 (AP-1 to the MMP-2 promoter diminished at the highest dosage level of Selaginellatamariscina. The DNA-binding activity of specificity protein 1 (SP-1 to the MMP-9 promoter was also suppressed at the same concentration. Selaginellatamariscina did not affect the mitogen-activated protein kinase signaling pathway, but did inhibit the effects of gelatinase by reducing the activation of serine-threonine kinase Akt. CONCLUSIONS: These results demonstrate that Selaginellatamariscina may be a potent adjuvant therapeutic agent in the prevention of oral cancer.

  3. Modulation of Golgi-associated microtubule nucleation throughout the cell cycle

    OpenAIRE

    Maia, Ana Rita Ramada; Zhu, Xiaodong; Miller, Paul; Gu, Guoqiang; Maiato, Helder; Kaverina, Irina

    2013-01-01

    A microtubule (MT) sub-population that emanates from Golgi membrane has been recently shown to comprise a significant part of MT network in interphase cells. In this study, we address whether Golgi membrane, which is being extensively remodeled throughout the cell cycle, retains its ability to nucleate MTs at diverse cell cycle stages. Live cell imaging and immunofluorescence microscopy reveals that Golgi-derived MTs form at multiple stages of the cell cycle, including G1, G2 and distinct pha...

  4. 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

  5. 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

  6. N-WASP is a novel regulator of hair-follicle cycling that controls antiproliferative TGF{beta} pathways

    DEFF Research Database (Denmark)

    Lefever, Tine; Pedersen, Esben; Basse, Astrid;

    2010-01-01

    N-WASP is a cytoplasmic molecule mediating Arp2/3 nucleated actin polymerization. Mice with a keratinocyte-specific deletion of the gene encoding N-WASP showed normal interfollicular epidermis, but delayed hair-follicle morphogenesis and abnormal hair-follicle cycling, associated with cyclic...... control cells and enhanced expression of the gene encoding the cell-cycle inhibitor p15INK4B, a TGFbeta target gene. Inhibition of TGFbeta signaling blocked overexpression of p15INK4B and restored proliferation of N-WASP-deficient keratinocytes in vitro. However, induction of N-WASP gene deletion in vitro...... did not result in obvious changes in TGFbeta signaling or growth of keratinocytes, indicating that the in vivo environment is required for the phenotype development. These data identify the actin nucleation regulator N-WASP as a novel element of hair-cycle control that modulates the antiproliferative...

  7. DUBbing Cancer: Deubiquitylating Enzymes Involved in Epigenetics, DNA Damage and the Cell Cycle As Therapeutic Targets

    Science.gov (United States)

    Pinto-Fernandez, Adan; Kessler, Benedikt M.

    2016-01-01

    Controlling cell proliferation is one of the hallmarks of cancer. A number of critical checkpoints ascertain progression through the different stages of the cell cycle, which can be aborted when perturbed, for instance by errors in DNA replication and repair. These molecular checkpoints are regulated by a number of proteins that need to be present at the right time and quantity. The ubiquitin system has emerged as a central player controlling the fate and function of such molecules such as cyclins, oncogenes and components of the DNA repair machinery. In particular, proteases that cleave ubiquitin chains, referred to as deubiquitylating enzymes (DUBs), have attracted recent attention due to their accessibility to modulation by small molecules. In this review, we describe recent evidence of the critical role of DUBs in aspects of cell cycle checkpoint control, associated DNA repair mechanisms and regulation of transcription, representing pathways altered in cancer. Therefore, DUBs involved in these processes emerge as potentially critical targets for the treatment of not only hematological, but potentially also solid tumors.

  8. 213Bi-anti-EGFR radioimmunoconjugates and X-ray irradiation trigger different cell death pathways in squamous cell carcinoma cells

    International Nuclear Information System (INIS)

    Introduction: Treatment of patients with squamous cell carcinoma of head and neck is hampered by resistance of tumor cells to irradiation. Additional therapies enhancing the effect of X-ray irradiation may be beneficial. Antibodies targeting EGFR have been shown to improve the efficacy of radiation therapy. Therefore, we analyzed cytotoxicity of 213Bi-anti-EGFR immunoconjugates in combination with X-ray irradiation. Methods: The monoclonal anti-EGFR antibody matuzumab was coupled to CHX-A”-DTPA forming stable complexes with 213Bi. Cytotoxicity of X-ray radiation, of treatment with 213Bi-anti-EGFR monoclonal antibodies (MAb) or of a combined treatment regimen was assayed using cell proliferation and colony formation assays in UD-SCC5 cells. Key proteins of cell-cycle arrest and cell death were examined by Western blot analysis. Cell cycle analysis was performed by flow cytometry. DNA double-strand breaks were detected via γH2AX and quantified using Definiens™ software. Results: Irradiation with X-rays or treatment with 213Bi-anti-EGFR-MAb resulted in median lethal dose (LD50) values of 12 Gy or 130 kBq/mL, respectively. Treatment with 37 kBq/mL of 213Bi-anti-EGFR-MAb or 2 Gy of X-rays had only little effect on colony formation of UD-SCC5 cells. In contrast, a combined treatment regimen (37 kBq/mL plus 2 Gy) significantly decreased colony formation and enhanced the formation of DNA double-strand breaks. As revealed by flow cytometry, radiation treatments caused accumulation of cells in the G0/G1 phase. Both treatment with 213Bi-anti-EGFR immunoconjugates and application of the combined treatment regimen triggered activation of genes of signaling pathways involved in cell-cycle arrest and induction of apoptosis like p21/Waf, GADD45, Puma and Bax, which were only marginally modulated by X-ray irradiation of cells. Conclusions: 213Bi-anti-EGFR-MAb enhances cytotoxicity of X-ray irradiation in UD-SCC5 cells most probably due to effective induction of DNA double

  9. 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.

  10. Cilium, centrosome and cell cycle regulation in polycystic kidney disease.

    Science.gov (United States)

    Lee, Kyung; Battini, Lorenzo; Gusella, G Luca

    2011-10-01

    Polycystic kidney disease is the defining condition of a group of common life-threatening genetic disorders characterized by the bilateral formation and progressive expansion of renal cysts that lead to end stage kidney disease. Although a large body of information has been acquired in the past years about the cellular functions that characterize the cystic cells, the mechanisms triggering the cystogenic conversion are just starting to emerge. Recent findings link defects in ciliary functions, planar cell polarity pathway, and centrosome integrity in early cystic development. Many of the signals dysregulated during cystogenesis may converge on the centrosome for its central function as a structural support for cilia formation and a coordinator of protein trafficking, polarity, and cell division. Here, we will discuss the contribution of proliferation, cilium and planar cell polarity to the cystic signal and will analyze in particular the possible role that the basal bodies/centrosome may play in the cystogenetic mechanisms. This article is part of a Special Issue entitled: Polycystic Kidney Disease. PMID:21376807

  11. Comparison of life cycle greenhouse gases from natural gas pathways for medium and heavy-duty vehicles.

    Science.gov (United States)

    Tong, Fan; Jaramillo, Paulina; Azevedo, Inês M L

    2015-06-16

    The low-cost and abundant supply of shale gas in the United States has increased the interest in using natural gas for transportation. We compare the life cycle greenhouse gas (GHG) emissions from different natural gas pathways for medium and heavy-duty vehicles (MHDVs). For Class 8 tractor-trailers and refuse trucks, none of the natural gas pathways provide emissions reductions per unit of freight-distance moved compared to diesel trucks. When compared to the petroleum-based fuels currently used in these vehicles, CNG and centrally produced LNG increase emissions by 0-3% and 2-13%, respectively, for Class 8 trucks. Battery electric vehicles (BEVs) powered with natural gas-produced electricity are the only fuel-technology combination that achieves emission reductions for Class 8 transit buses (31% reduction compared to the petroleum-fueled vehicles). For non-Class 8 trucks (pick-up trucks, parcel delivery trucks, and box trucks), BEVs reduce emissions significantly (31-40%) compared to their diesel or gasoline counterparts. CNG and propane achieve relatively smaller emissions reductions (0-6% and 19%, respectively, compared to the petroleum-based fuels), while other natural gas pathways increase emissions for non-Class 8 MHDVs. While using natural gas to fuel electric vehicles could achieve large emission reductions for medium-duty trucks, the results suggest there are no great opportunities to achieve large emission reductions for Class 8 trucks through natural gas pathways with current technologies. There are strategies to reduce the carbon footprint of using natural gas for MHDVs, ranging from increasing vehicle fuel efficiency, reducing life cycle methane leakage rate, to achieving the same payloads and cargo volumes as conventional diesel trucks. PMID:25938939

  12. 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

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

    KAUST Repository

    Mangla, Karan

    2010-02-01

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

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

    Directory of Open Access Journals (Sweden)

    Shunsuke Nojiri

    2014-03-01

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

  15. The Hippo Pathway Regulates Homeostatic Growth of Stem Cell Niche Precursors in the Drosophila Ovary

    OpenAIRE

    Sarikaya, Didem P.; Extavour, Cassandra G.

    2015-01-01

    The Hippo pathway regulates organ size, stem cell proliferation and tumorigenesis in adult organs. Whether the Hippo pathway influences establishment of stem cell niche size to accommodate changes in organ size, however, has received little attention. Here, we ask whether Hippo signaling influences the number of stem cell niches that are established during development of the Drosophila larval ovary, and whether it interacts with the same or different effector signaling pathways in different c...

  16. Luteolin modulates 6-hydroxydopamine-induced transcriptional changes of stress response pathways in PC12 cells.

    Directory of Open Access Journals (Sweden)

    Ling-Wei Hu

    Full Text Available The neurotoxin 6-hydroxydopamine (6-OHDA, which causes transcriptional changes associated with oxidative and proteotoxic stress, has been widely used to generate an experimental model of Parkinson's disease. The food-derived compound luteolin has multi-target actions including antioxidant, anti-inflammatory and neurotrophic activities. The aim of this study is to investigate how luteolin affects 6-OHDA-mediated stress response pathways. The results showed that when PC12 cells were pre-treated with luteolin (20 µM 30 min prior to 6-OHDA (100 µM exposure, 6-OHDA-induced ROS overproduction, cytotoxicity, caspase-3 activation, and mRNA expression of BIM, TRB3 and GADD34 were significantly attenuated. Moreover, 6-OHDA-mediated cell cycle arrest and transcription of p53 target genes, p21, GADD45α and PUMA, were reduced by luteolin. Luteolin also significantly down-regulated 6-OHDA-mediated unfolded protein response (UPR, leading to decreases in phospho-eIF2α, ATF4, GRP78 and CHOP. In addition, luteolin attenuated 6-OHDA-induced Nrf2-mediated HO-1 and GCLC. Taken together, these results suggest that diminishing intracellular ROS formation and down-regulation of p53, UPR and Nrf2-ARE pathways may be involved in the neuroprotective effect of luteolin.

  17. 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.

  18. Butyrate-induced proapoptotic and antiangiogenic pathways in EAT cells require activation of CAD and downregulation of VEGF

    International Nuclear Information System (INIS)

    Butyrate, a short-chain fatty acid produced in the colon, induces cell cycle arrest, differentiation, and apoptosis in transformed cell lines. In this report, we study the effects of butyrate (BuA) on the growth of Ehrlich ascites tumor (EAT) cells in vivo. BuA, when injected intraperitoneally (i.p) into mice, inhibited proliferation of EAT cells. Further, induction of apoptosis in EAT cells was monitored by nuclear condensation, annexin-V staining, DNA fragmentation, and translocation of caspase-activated DNase into nucleus upon BuA-treatment. Ac-DEVD-CHO, a caspase-3 inhibitor, completely inhibited BuA-induced apoptosis, indicating that activation of caspase-3 mediates the apoptotic pathway in EAT cells. The proapoptotic effect of BuA also reflects on the antiangiogenic pathway in EAT cells. The antiangiogenic effect of BuA in vivo was demonstrated by the downregulation of the secretion of VEGF in EAT cells. CD31 immunohistochemical staining of peritoneum sections clearly indicated a potential angioinhibitory effect of BuA in EAT cells. These results suggest that BuA, besides regulating other fundamental cellular processes, is able to modulate the expression/secretion of the key angiogenic growth factor VEGF in EAT cells

  19. Gold nanoparticle sensitize radiotherapy of prostate cancer cells by regulation of the cell cycle

    Science.gov (United States)

    Roa, Wilson; Zhang, Xiaojing; Guo, Linghong; Shaw, Andrew; Hu, Xiuying; Xiong, Yeping; Gulavita, Sunil; Patel, Samir; Sun, Xuejun; Chen, Jie; Moore, Ronald; Xing, James Z.

    2009-09-01

    Glucose-capped gold nanoparticles (Glu-GNPs) have been used to improve cellular targeting and radio-sensitization. In this study, we explored the mechanism of Glu-GNP enhanced radiation sensitivity in radiation-resistant human prostate cancer cells. Cell survival and proliferation were measured using MTT and clonogenic assay. Flow cytometry with staining by propidium iodide (PI) was performed to study the cell cycle changes induced by Glu-GNPs, and western blotting was used to determine the expression of p53 and cyclin proteins that correlated to cell cycle regulation. With 2 Gy of ortho-voltage irradiation, Glu-GNP showed a 1.5-2.0 fold enhancement in growth inhibition when compared to x-rays alone. Comparing the cell cycle change, Glu-GNPs induced acceleration in the G0/G1 phase and accumulation of cells in the G2/M phase at 29.8% versus 18.4% for controls at 24 h. G2/M arrest was accompanied by decreased expression of p53 and cyclin A, and increased expression of cyclin B1 and cyclin E. In conclusion, Glu-GNPs trigger activation of the CDK kinases leading to cell cycle acceleration in the G0/G1 phase and accumulation in the G2/M phase. This activation is accompanied by a striking sensitization to ionizing radiation, which may have clinical implications.

  20. Alisol B acetate induces apoptosis of SGC7901 cells via mitochondrial and phosphatidylinositol 3-kinases/Akt signaling pathways

    Institute of Scientific and Technical Information of China (English)

    Yong-Hong Xu; Li-Jie Zhao; Yan Li

    2009-01-01

    AIM: To examine the effect of alisol B acetate on the growth of human gastric cancer cell line SGC7901 and its possible mechanism of action. METHODS: The cytotoxic effect of alisol B acetate on SGC7901 cells was measured by 3-(4,5-dimethylthiazol- 2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Phase-contrast and electron microscopy were used to observe the morphological changes. Cell cycle and mitochondrial transmembrane potential (ΔΨm) were determined by flow cytometry. Western blotting was used to detect the expression of apoptosis-regulated gene Bcl-2, Bax, Apaf-1, caspase-3, caspase-9, Akt, P-Akt and phosphatidylinositol 3-kinases (PI3K). RESULTS: Alisol B acetate inhibited the proliferation of SGC7901 cell line in a time- and dose-dependent manner. PI staining showed that alisol B acetate can change the cell cycle distribution of SGC7901, increase the proportion of cells in G0-G1 phase and decrease the proportion of S phase cells and G2-M phase cells. Alisol B acetate at a concentration of 30 μmol/L induced apoptosis after 24, 48 and 72 h incubation, with occurrence rates of apoptotic cells of 4.36%, 14.42% and 21.16%, respectively. Phase-contrast and electron microscopy revealed that the nuclear fragmentation and chromosomal condensed, cells shrank and attachment loss appeared in the SGC7901 treated with alisol B acetate. Apoptosis of SGC7901 with alisol B acetate. Apoptosis of SGC7901 cells was associated with cell cycle arrest, caspase-3 and caspase-9 activation, loss of mitochondrial membrane potential and up-regulation of the ratio of Bax/Bcl-2 and inhibition of the PI3K/Akt. CONCLUSION: Alisol B acetate exhibits an antiproliferative effect in SGC7901 cells by inducing apoptosis. Apoptosis of SGC7901 cells involves mitochondria-caspase and PI3K/Akt dependent pathways.

  1. Inhibition of NAMPT pathway by FK866 activates the function of p53 in HEK293T cells

    International Nuclear Information System (INIS)

    Highlights: ► In 293T cells, p53 is considered to be inactive due to its interaction with the large T-antigen. ► Acetylation of p53 at lysine 382 is important for its functional activation. ► First evidence to document the presence of a functional p53 in 293T cells. ► Inhibition of NAMPT/SIRT pathway by FK866 in 293T cells increases the functional activity of p53. ► This activation of p53 involves reversible acetylation of p53 at lysine 382. -- Abstract: Inactivation of p53 protein by endogenous and exogenous carcinogens is involved in the pathogenesis of different human malignancies. In cancer associated with SV-40 DNA tumor virus, p53 is considered to be non-functional mainly due to its interaction with the large T-antigen. Using the 293T cell line (HEK293 cells transformed with large T antigen) as a model, we provide evidence that p53 is one of the critical downstream targets involved in FK866-mediated killing of 293T cells. A reduced rate of apoptosis and an increased number of cells in S-phase was accompanied after knockdown of p53 in these cells. Inhibition of NAMPT by FK866, or inhibition of SIRT by nicotinamide decreased proliferation and triggered death of 293T cells involving the p53 acetylation pathway. Additionally, knockdown of p53 attenuated the effect of FK866 on cell proliferation, apoptosis, and cell cycle arrest. The data presented here shed light on two important facts: (1) that p53 in 293T cells is active in the presence of FK866, an inhibitor of NAMPT pathway; (2) the apoptosis induced by FK866 in 293T cells is associated with increased acetylation of p53 at Lys382, which is required for the functional activity of p53.

  2. Molecular Signaling Pathways Mediating Osteoclastogenesis Induced by Prostate Cancer Cells

    International Nuclear Information System (INIS)

    Advanced prostate cancer commonly metastasizes to bone leading to osteoblastic and osteolytic lesions. Although an osteolytic component governed by activation of bone resorbing osteoclasts is prominent in prostate cancer metastasis, the molecular mechanisms of prostate cancer-induced osteoclastogenesis are not well-understood. We studied the effect of soluble mediators released from human prostate carcinoma cells on osteoclast formation from mouse bone marrow and RAW 264.7 monocytes. Soluble factors released from human prostate carcinoma cells significantly increased viability of naïve bone marrow monocytes, as well as osteoclastogenesis from precursors primed with receptor activator of nuclear factor κ-B ligand (RANKL). The prostate cancer-induced osteoclastogenesis was not mediated by RANKL as it was not inhibited by osteoprotegerin (OPG). However inhibition of TGFβ receptor I (TβRI), or macrophage-colony stimulating factor (MCSF) resulted in attenuation of prostate cancer-induced osteoclastogenesis. We characterized the signaling pathways induced in osteoclast precursors by soluble mediators released from human prostate carcinoma cells. Prostate cancer factors increased basal calcium levels and calcium fluctuations, induced nuclear localization of nuclear factor of activated t-cells (NFAT)c1, and activated prolonged phosphorylation of ERK1/2 in RANKL-primed osteoclast precursors. Inhibition of calcium signaling, NFATc1 activation, and ERK1/2 phosphorylation significantly reduced the ability of prostate cancer mediators to stimulate osteoclastogenesis. This study reveals the molecular mechanisms underlying the direct osteoclastogenic effect of prostate cancer derived factors, which may be beneficial in developing novel osteoclast-targeting therapeutic approaches

  3. Norcantharidin inhibits Wnt signal pathway via promoter demethylation of WIF-1 in human non-small cell lung cancer.

    Science.gov (United States)

    Xie, Junran; Zhang, Yaping; Hu, Xuming; Lv, Ran; Xiao, Dongju; Jiang, Li; Bao, Qi

    2015-05-01

    Wingless-type (Wnt) family of secreted glycoproteins is a group of signal molecules implicated in oncogenesis. Abnormal activation of Wnt signal pathway is associated with a variety of human cancers, including non-small cell lung cancer (NSCLC). Wnt antagonists, such as the secreted frizzled-related protein (SFRP) family, Wnt inhibitory factor-1 (WIF-1) and cerberus, inhibit Wnt signal pathway by directly binding to Wnt molecules. Norcantharidin (NCTD) is known to possess anticancer activity but less nephrotoxicity than cantharidin. In this study, we found that NCTD inhibited cell proliferation, induced apoptosis, arrested cell cycle and suppressed cell invasion/migration in vitro. Additionally, Wnt signal pathway transcription was also suppressed. NCTD treatment blocked cytoplasmic translocation of beta-catenin into the nucleus. Alterations of apoptosis-related proteins, such as Bax, cleaved caspase-3 (pro-apoptotic) and Bcl-2 (anti-apoptotic), had been detected. Furthermore, the expression levels of WIF-1 and SFRP1 were significantly increased in NCTD-treated groups compared with negative control (NC) groups. Abnormal methylation was observed in NC groups, while NCTD treatment promoted WIF-1 demethylation. The present study revealed that NCTD activated WIF-1 via promoter demethylation, inhibiting the canonical Wnt signal pathway in NSCLC, which may present a new therapeutic target in vivo. PMID:25814287

  4. DNA damage activates a spatially distinct late cytoplasmic cell-cycle checkpoint network controlled by MK2-mediated RNA stabilization

    DEFF Research Database (Denmark)

    Reinhardt, H Christian; Hasskamp, Pia; Schmedding, Ingolf;

    2010-01-01

    Following genotoxic stress, cells activate a complex kinase-based signaling network to arrest the cell cycle and initiate DNA repair. p53-defective tumor cells rewire their checkpoint response and become dependent on the p38/MK2 pathway for survival after DNA damage, despite a functional ATR-Chk1...... pathway. We used functional genetics to dissect the contributions of Chk1 and MK2 to checkpoint control. We show that nuclear Chk1 activity is essential to establish a G(2)/M checkpoint, while cytoplasmic MK2 activity is critical for prolonged checkpoint maintenance through a process of...... posttranscriptional mRNA stabilization. Following DNA damage, the p38/MK2 complex relocalizes from nucleus to cytoplasm where MK2 phosphorylates hnRNPA0, to stabilize Gadd45α mRNA, while p38 phosphorylates and releases the translational inhibitor TIAR. In addition, MK2 phosphorylates PARN, blocking Gadd45α m...

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

    DEFF Research Database (Denmark)

    Oleksiewicz, M.B.; Alexandersen, Søren

    1997-01-01

    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...

  6. Effect of microenviroment hypoxia on glioma cells radiosensitivity through cancer stem cell pathway

    International Nuclear Information System (INIS)

    Objective: To investigate the effect of microenviroment hypoxia on glioma cells radiosensitivity through cancer stem pathway, and to explore the related mechanism. Methods: Glioma cell lines SHG44 and U251 were cultured in normoxia (20% O2) or continuous hypoxia (1% O2) for 12 and 24 h. The fraction of glioma cells with positive expression of CD133 was assayed by flow cytometry. The radiosensitivity of glioma cells was determined by clonogenic cell assay. Western blotting was used to investigate the expressions of HIF-1 α and its downstream gene Notch 1. Results: The fraction of glioma cells with positive expression of CD133 was higher after hypoxic culture for 12 and 24 h than that of the corresponding cells cultured in normoxia. Compared to the cells cultured in normoxia, SF2 (survival fraction at 2 Gy) were enhanced significantly in SHG44 and U251 cells cultured in hypoxia for 12 and 24 h. The OER (oxygen-enhancement ratio) of SHG44 cells in hypoxia for 12 and 24 h was 1.54 and 1.38, respectively. The OER of U251 cells was 1.44 and 1.23, respectively. The radiosensitivity of these two cell line was decreased in hypoxia. The protein expressions of HIF-1 α and Notch 1 genes were elevated more significantly for cells cultured in hypoxia for 12 and 24 h than for those in normoxia. Conclusions: Microenviroment hypoxia could increase the radioresistance of glioma cells through enrichment of cancer stem cells, and HIF-1 α-Notch 1 signal pathway may play an important role in this process. (authors)

  7. 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

  8. Inhibitive effect of 3-bromopyruvic acid on human breast cancer MCF-7 cells involves cell cycle arrest and apoptotic induction

    Institute of Scientific and Technical Information of China (English)

    LIU Xiao-hong; ZHENG Xue-fang; WANG Yong-li

    2009-01-01

    Background Breast cancer is one of the most common malignancies in women and is highly resistant to chemotherapy. Due to its high tumour selectivity, 3-bromopyruvic acid (3-BrPA), a well-known inhibitor of energy metabolism has been proposed as a specific anticancer agent. The present study determined the effect of 3-BrPA on proliferation, cell cycle and apoptosis in the human breast cancer MCF-7 cell line and other antitumour mechanisms. Methods MCF-7 cells were treated with various concentrations of 3-BrPA for 1-4 days, and cell growth was measured by 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyl tetrazolium bromide assay. Marked morphological changes in MCF-7 cells after treatment with 3-BrPA were observed using transmission electron microscopy. The distributions of the cell cycle and apoptosis were analyzed by flow cytometry. Immunohistochemistry was used to indicate the changes in the expression of Bcl-2, c-Myc, and mutant p53. Results 3-BrPA (25 μg/ml) significantly inhibited the proliferation of MCF-7 cells in a time-dependent manner. The MCF-7 cells exposed to 3-BrPA showed the typical morphological characteristics of apoptosis, including karyopycnosis, nuclear condensation and oversize cytoplasmic particles. In addition, flow cytometric assay also showed more apoptotic cells after 3-BrPA stimulation. The cells at the GO and G1 phases were dramatically decreased while cells at the S and G2/M phases were increased in response to 3-BrPA treatment after 48 hours. Furthermore, 3-BrPA stimulation decreased the expressions of Bcl-2, c-Myc and mutant p53, which were strongly associated with the programmed cell death signal transduction pathway. Conclusion 3-BrPA inhibits proliferation, induces S phase and G2/M phase arrest, and promotes apoptosis in MCF-7 cells, which processes might be mediated by the downregulation of the expressions of Bcl-2, c-Myc and mutant p53.

  9. Supercritical carbon dioxide extract of Physalis peruviana induced cell cycle arrest and apoptosis in human lung cancer H661 cells.

    Science.gov (United States)

    Wu, Shu-Jing; Chang, Shun-Pang; Lin, Doung-Liang; Wang, Shyh-Shyan; Hou, Fwu-Feuu; Ng, Lean-Teik

    2009-06-01

    Physalis peruviana L. (PP) is a popular folk medicine used for treating cancer, leukemia, hepatitis, rheumatism and other diseases. In this study, our objectives were to examine the total flavonoid and phenol content of different PP extracts (aqueous: HWEPP; ethanolic: EEPP; supercritical carbon dioxide: SCEPP-0, SCEPP-4 and SCEPP-5) and their antiproliferative effects in human lung cancer H661 cells. Among all the extracts tested, results showed that SCEPP-5 possessed the highest total flavonoid (226.19 +/- 4.15 mg/g) and phenol (100.82 +/- 6.25 mg/g) contents. SCEPP-5 also demonstrated the most potent inhibitory effect on H661 cell proliferation. Using DNA ladder and flow cytometry analysis, SCEPP-5 effectively induced H661 cell apoptosis as demonstrated by the accumulation of Sub-G1 peak and fragmentation of DNA. SCEPP-5 not only induced cell cycle arrest at S phase, it also up-regulated the expression of pro-apoptotic protein (Bax) and down-regulated the inhibitor of apoptosis protein (IAP). Furthermore, the apoptotic induction in H661 cells was found to associate with an elevated p53 protein expression, cytochrome c release, caspase-3 activation and PARP cleavage. Taken together, these results conclude that SCEPP-5 induced cell cycle arrest at S phase, and its apoptotic induction could be mediated through the p53-dependent pathway and modification of Bax and XIAP proteins expression. The results have also provided important pharmacological backgrounds for the potential use of PP supercritical fluid extract as products for cancer prevention. PMID:19425186

  10. 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.

  11. Pathways to ischemic neuronal cell death: are sex differences relevant?

    Directory of Open Access Journals (Sweden)

    McCullough Louise D

    2008-06-01

    Full Text Available Abstract We have known for some time that the epidemiology of human stroke is sexually dimorphic until late in life, well beyond the years of reproductive senescence and menopause. Now, a new concept is emerging: the mechanisms and outcome of cerebral ischemic injury are influenced strongly by biological sex as well as the availability of sex steroids to the brain. The principal mammalian estrogen (17 β estradiol or E2 is neuroprotective in many types of brain injury and has been the major focus of investigation over the past several decades. However, it is becoming increasingly clear that although hormones are a major contributor to sex-specific outcomes, they do not fully account for sex-specific responses to cerebral ischemia. The purpose of this review is to highlight recent studies in cell culture and animal models that suggest that genetic sex determines experimental stroke outcome and that divergent cell death pathways are activated after an ischemic insult. These sex differences need to be identified if we are to develop efficacious neuroprotective agents for use in stroke patients.

  12. Mechanisms involved in alternariol-induced cell cycle arrest

    International Nuclear Information System (INIS)

    Alternariol (AOH), a mycotoxin produced by Alternaria sp, is often found as a contaminant in fruit and cereal products. Here we employed the murine macrophage cell line RAW 264.7 to test the hypothesis that AOH causes toxicity as a response to DNA damage. AOH at concentrations of 15–30 μM almost completely blocked cell proliferation. Within 30 min treatment