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Sample records for caveolin-1 mediated radioresistance

  1. Caveolin-1 mediated radioresistance of 3D grown pancreatic cancer cells

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    Hehlgans, Stephanie; Eke, Iris; Storch, Katja; Haase, Michael; Baretton, Gustavo B.; Cordes, Nils

    2009-01-01

    Background and purpose: Resistance of pancreatic ductal adenocarcinoma (PDAC) to chemo- and radiotherapy is a major obstacle. The integral membrane protein Caveolin-1 (Cav-1) has been suggested as a potent target in human pancreatic carcinoma cells. Materials and methods: Human pancreatic tumor cells were examined in a three-dimensional (3D) cell culture model with regard to clonogenic survival, apoptosis, radiogenic DNA-double strand breaks and protein expression and phosphorylation under siRNA-mediated knockdown of Cav-1 without and in combination with irradiation (X-rays, 0-6 Gy). Immunohistochemistry was used to assess Cav-1 expression in biopsies from patients with PDAC. Results: Tumor cells in PDAC showed significantly higher Cav-1 expression relative to tumor stroma. Cav-1 knockdown significantly reduced β1 integrin expression and Akt phosphorylation, induced Caspase 3- and Caspase 8-dependent apoptosis and enhanced the radiosensitivity of 3D cell cultures. While cell cycling and Cav-1 promoter activity remained stable, Cav-1 knockdown-induced radiosensitization correlated with elevated numbers of residual DNA-double strand breaks. Conclusions: Our data strongly support the concept of Cav-1 as a potent target in pancreatic carcinoma cells due to radiosensitization and Cav-1 overexpression in tumor cells of PDAC. 3D cell cultures are powerful and useful tools for the testing of novel targeting strategies to optimize conventional radio- and chemotherapy regimes for PDAC.

  2. Phospho-Caveolin-1 Mediates Integrin-Regulated Membrane Domain Internalisation

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    del Pozo, Miguel A.; Alderson, Nazilla B.; Grande-García, Araceli; Balasubramanian, Nagaraj; Schwartz, Martin A.; Kiosses, William B.; Anderson, Richard G.W.

    2005-01-01

    Growth of normal cells is anchorage-dependent because signalling through multiple pathways including Erk, PI 3-kinase and Rac requires integrin-mediated cell adhesion 1. Components of these pathways localize to low density, cholesterol-rich domains in the plasma membrane named “lipid rafts” 2,3 or “cholesterol enriched membrane microdomains” (CEMM) 4. We previously reported that integrin-mediated adhesion regulates CEMM trafficking such that cell detachment from the extracellular matrix (ECM) triggers CEMM internalisation and clearance from the plasma membrane 5. We now report that this internalisation is mediated by dynamin-2 and caveolin-1. Internalisation requires phosphorylation of caveolin-1 on tyrosine 14. A shift in localisation of phospho-caveolin-1 from focal adhesions to caveolae induces CEMM internalisation upon cell detachment, which mediates inhibition of Erk, PI 3-kinase and Rac. These data define a novel molecular mechanism for growth and tumour suppression by caveolin-1. PMID:16113676

  3. Interaction of caveolin-1 with Ku70 inhibits Bax-mediated apoptosis.

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    Huafei Zou

    Full Text Available Caveolin-1, the structural protein component of caveolae, acts as a scaffolding protein that functionally regulates signaling molecules. We show that knockdown of caveolin-1 protein expression enhances chemotherapeutic drug-induced apoptosis and inhibits long-term survival of colon cancer cells. In vitro studies demonstrate that caveolin-1 is a novel Ku70-binding protein, as shown by the binding of the scaffolding domain of caveolin-1 (amino acids 82-101 to the caveolin-binding domain (CBD of Ku70 (amino acids 471-478. Cell culture data show that caveolin-1 binds Ku70 after treatment with chemotherapeutic drugs. Mechanistically, we found that binding of caveolin-1 to Ku70 inhibits the chemotherapeutic drug-induced release of Bax from Ku70, activation of Bax, translocation of Bax to mitochondria and apoptosis. Potentiation of apoptosis by knockdown of caveolin-1 protein expression is greatly reduced in the absence of Bax expression. Finally, we found that overexpression of wild type Ku70, but not a mutant form of Ku70 that cannot bind to caveolin-1 (Ku70 Φ→A, limits the chemotherapeutic drug-induced Ku70/Bax dissociation and apoptosis. Thus, caveolin-1 acts as an anti-apoptotic protein in colon cancer cells by binding to Ku70 and inhibiting Bax-dependent cell death.

  4. Caveolin-1-mediated apolipoprotein A-I membrane binding sites are not required for cholesterol efflux.

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    Soazig Le Lay

    Full Text Available Caveolin-1 (Cav1, a structural protein required for the formation of invaginated membrane domains known as caveolae, has been implicated in cholesterol trafficking and homeostasis. Here we investigated the contribution of Cav1 to apolipoprotein A-I (apoA-I cell surface binding and intracellular processing using mouse embryonic fibroblasts (MEFs derived from wild type (WT or Cav1-deficient (Cav1(-/- animals. We found that cells expressing Cav1 have 2.6-fold more apoA-I binding sites than Cav1(-/- cells although these additional binding sites are not associated with detergent-free lipid rafts. Further, Cav1-mediated binding targets apoA-I for internalization and degradation and these processes are not correlated to cholesterol efflux. Despite lower apoA-I binding, cholesterol efflux from Cav1(-/- MEFs is 1.7-fold higher than from WT MEFs. Stimulation of ABCA1 expression with an LXR agonist enhances cholesterol efflux from both WT and Cav1(-/- cells without increasing apoA-I surface binding or affecting apoA-I processing. Our results indicate that there are at least two independent lipid binding sites for apoA-I; Cav1-mediated apoA-I surface binding and uptake is not linked to cholesterol efflux, indicating that membrane domains other than caveolae regulate ABCA1-mediated cholesterol efflux.

  5. Electroacupuncture Exerts Neuroprotection through Caveolin-1 Mediated Molecular Pathway in Intracerebral Hemorrhage of Rats.

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    Li, Hui-Qin; Li, Yan; Chen, Zi-Xian; Zhang, Xiao-Guang; Zheng, Xia-Wei; Yang, Wen-Ting; Chen, Shuang; Zheng, Guo-Qing

    2016-01-01

    Spontaneous intracerebral hemorrhage (ICH) is one of the most devastating types of stroke. Here, we aim to demonstrate that electroacupuncture on Baihui (GV20) exerts neuroprotection for acute ICH possibly via the caveolin-1/matrix metalloproteinase/blood-brain barrier permeability pathway. The model of ICH was established by using collagenase VII. Rats were randomly divided into three groups: Sham-operation group, Sham electroacupuncture group, and electroacupuncture group. Each group was further divided into 4 subgroups according to the time points of 6 h, 1 d, 3 d, and 7 d after ICH. The methods were used including examination of neurological deficit scores according to Longa's scale, measurement of blood-brain barrier permeability through Evans Blue content, in situ immunofluorescent detection of caveolin-1 in brains, western blot analysis of caveolin-1 in brains, and in situ zymography for measuring matrix metalloproteinase-2/9 activity in brains. Compared with Sham electroacupuncture group, electroacupuncture group has resulted in a significant improvement in neurological deficit scores and in a reduction in Evans Blue content, expression of caveolin-1, and activity of matrix metalloproteinase-2/9 at 6 h, 1 d, 3 d, and 7 d after ICH ( P electroacupuncture on GV20 can improve neurological deficit scores and reduce blood-brain barrier permeability after ICH, and the mechanism possibly targets caveolin-1/matrix metalloproteinase/blood-brain barrier permeability pathway.

  6. Caveolin-1 enhances resveratrol-mediated cytotoxicity and transport in a hepatocellular carcinoma model

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    Yang Hui-ling

    2009-03-01

    Full Text Available Abstract Background Resveratrol (RES, an estrogen analog, is considered as a potential cancer chemo-preventive agent. However, it remains unclear how RES is transported into cells. In this study, we observed that Caveolin-1(CAV1 expression can increase the cytotoxic and pro-apoptotic activity of RES in a dose- and time-dependent manner both in vitro and in vivo in a Hepatocellular Carcinoma animal model. Methods High performance liquid chromatography (HPLC demonstrated that RES intra-cellular concentration is increased about 2-fold in cells stably expressing CAV1 or CAVM1 (a scaffolding domain (81-101AA-defective CAV1 mutant compared to the untransduced human Hepatoblastoma cell line (HepG2 or after transduction with the green fluorescent protein (GFP control vector. The increased intra-cellular transport of RES was abolished in cells stably expressing CAVM2 (a cholesterol shuttle domain (143-156AA-defective CAV1 mutant or CAVRNAi. In order to further characterize CAV1-dependent RES transport, we synthesized RES-dansyl chloride derivatives as fluorescent probes to visualize the transport process, which demonstrated a distribution consistent with that of CAV1 in HepG2 cells. Results In addition, RES endocytosis was not mediated by estrogen receptor (ER α and β, as suggested by lack of competitive inhibition by estrogen or Tamoxifen. Pathway analysis showed that RES can up-regulate the expression of endogenous CAV1; this activates further the MAPK pathway and caspase-3 expression. Discussion This study provides novel insights about the role played by CAV1 in modulating cellular sensitivity to RES through enhancement of its internalization and trafficking.

  7. Electroacupuncture Exerts Neuroprotection through Caveolin-1 Mediated Molecular Pathway in Intracerebral Hemorrhage of Rats

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    Hui-Qin Li

    2016-01-01

    Full Text Available Spontaneous intracerebral hemorrhage (ICH is one of the most devastating types of stroke. Here, we aim to demonstrate that electroacupuncture on Baihui (GV20 exerts neuroprotection for acute ICH possibly via the caveolin-1/matrix metalloproteinase/blood-brain barrier permeability pathway. The model of ICH was established by using collagenase VII. Rats were randomly divided into three groups: Sham-operation group, Sham electroacupuncture group, and electroacupuncture group. Each group was further divided into 4 subgroups according to the time points of 6 h, 1 d, 3 d, and 7 d after ICH. The methods were used including examination of neurological deficit scores according to Longa’s scale, measurement of blood-brain barrier permeability through Evans Blue content, in situ immunofluorescent detection of caveolin-1 in brains, western blot analysis of caveolin-1 in brains, and in situ zymography for measuring matrix metalloproteinase-2/9 activity in brains. Compared with Sham electroacupuncture group, electroacupuncture group has resulted in a significant improvement in neurological deficit scores and in a reduction in Evans Blue content, expression of caveolin-1, and activity of matrix metalloproteinase-2/9 at 6 h, 1 d, 3 d, and 7 d after ICH (P<0.05. In conclusion, the present results suggested that electroacupuncture on GV20 can improve neurological deficit scores and reduce blood-brain barrier permeability after ICH, and the mechanism possibly targets caveolin-1/matrix metalloproteinase/blood-brain barrier permeability pathway.

  8. Caveolin-1 and CDC42 mediated endocytosis of silica-coated iron oxide nanoparticles in HeLa cells

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    Nils Bohmer

    2015-01-01

    Full Text Available Nanomedicine is a rapidly growing field in nanotechnology, which has great potential in the development of new therapies for numerous diseases. For example iron oxide nanoparticles are in clinical use already in the thermotherapy of brain cancer. Although it has been shown, that tumor cells take up these particles in vitro, little is known about the internalization routes. Understanding of the underlying uptake mechanisms would be very useful for faster and precise development of nanoparticles for clinical applications. This study aims at the identification of key proteins, which are crucial for the active uptake of iron oxide nanoparticles by HeLa cells (human cervical cancer as a model cell line. Cells were transfected with specific siRNAs against Caveolin-1, Dynamin 2, Flotillin-1, Clathrin, PIP5Kα and CDC42. Knockdown of Caveolin-1 reduces endocytosis of superparamagnetic iron oxide nanoparticles (SPIONs and silica-coated iron oxide nanoparticles (SCIONs between 23 and 41%, depending on the surface characteristics of the nanoparticles and the experimental design. Knockdown of CDC42 showed a 46% decrease of the internalization of PEGylated SPIONs within 24 h incubation time. Knockdown of Dynamin 2, Flotillin-1, Clathrin and PIP5Kα caused no or only minor effects. Hence endocytosis in HeLa cells of iron oxide nanoparticles, used in this study, is mainly mediated by Caveolin-1 and CDC42. It is shown here for the first time, which proteins of the endocytotic pathway mediate the endocytosis of silica-coated iron oxide nanoparticles in HeLa cells in vitro. In future studies more experiments should be carried out with different cell lines and other well-defined nanoparticle species to elucidate possible general principles.

  9. Static pressure accelerates ox-LDL-induced cholesterol accumulation via SREBP-1-mediated caveolin-1 downregulation in cultured vascular smooth muscle cells

    International Nuclear Information System (INIS)

    Luo, Di-xian; Xia, Cheng-lai; Li, Jun-mu; Xiong, Yan; Yuan, Hao-yu; TANG, Zhen-Wang; Zeng, Yixin; Liao, Duan-fang

    2010-01-01

    Research highlights: → Vertical static pressure accelerates ox-LDL-induced cholesterol accumulation in cultured vascular smooth muscle cells. → Static pressure induces SREBP-1 activation. → Static pressure downregulates the expressions of caveolin-1 by activating SREBP-1. → Static pressure also downregulates the transcription of ABCA1 by activating SREBP-1. → Static pressure increases ox-LDL-induced cholesterol accumulation by SREBP-1-mediated caveolin-1 downregulation in vascular smooth muscle cells cultured in vitro. -- Abstract: Objective: To investigate the effect of static pressure on cholesterol accumulation in vascular smooth muscle cells (VSMCs) and its mechanism. Methods: Rat-derived VSMC cell line A10 treated with 50 mg/L ox-LDL and different static pressures (0, 60, 90, 120, 150, 180 mm Hg) in a custom-made pressure incubator for 48 h. Intracellular lipid droplets and lipid levels were assayed by oil red O staining and HPLC; The mRNA levels of caveolin-1 and ABCA1, the protein levels of caveolin-1 SREBP-1 and mature SREBP-1 were respectively detected by RT-PCR or western blot. ALLN, an inhibitor of SREBP metabolism, was used to elevate SREBP-1 protein level in VSMCs treated with static pressure. Results: Static pressures significantly not only increase intracellular lipid droplets in VSMCs, but also elevate cellular lipid content in a pressure-dependent manner. Intracellular free cholesterol (FC), cholesterol ester (CE), total cholesterol (TC) were respectively increased from 60.5 ± 2.8 mg/g, 31.8 ± 0.7 mg/g, 92.3 ± 2.1 mg/g at atmosphere pressure (ATM, 0 mm Hg) to 150.8 ± 9.4 mg/g, 235.9 ± 3.0 mg/g, 386.7 ± 6.4 mg/g at 180 mm Hg. At the same time, static pressures decrease the mRNA and protein levels of caveolin-1, and induce the activation and nuclear translocation of SREBP-1. ALLN increases the protein level of mature SREBP-1 and decreases caveolin-1 expression, so that cellular lipid levels were upregulated. Conclusion: Static

  10. Static pressure accelerates ox-LDL-induced cholesterol accumulation via SREBP-1-mediated caveolin-1 downregulation in cultured vascular smooth muscle cells

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    Luo, Di-xian, E-mail: luodixian_2@163.com [Department of Pharmacology, School of Pharmaceutics, Central South University, Changsha 410083, Hunan (China); Institute of Pharmacy and Pharmacology, College of Science and Technology, University of South China, Hengyang 421001, Hunan (China); First People' s Hospital of Chenzhou City, Chenzhou 423000, Hunan (China); Xia, Cheng-lai [Institute of Pharmacy and Pharmacology, College of Science and Technology, University of South China, Hengyang 421001, Hunan (China); Department of Pharmacy, Third Affiliated Hospital Medical College of Guangzhou, Guangzhou 510150, Guangdong (China); Li, Jun-mu [Institute of Pharmacy and Pharmacology, College of Science and Technology, University of South China, Hengyang 421001, Hunan (China); Xiong, Yan [Department of Pharmacology, School of Pharmaceutics, Central South University, Changsha 410083, Hunan (China); Yuan, Hao-yu [Institute of Pharmacy and Pharmacology, College of Science and Technology, University of South China, Hengyang 421001, Hunan (China); Lusong Center for Disease Control and Prevention, Zhuzhou 412000, Hunan (China); TANG, Zhen-Wang; Zeng, Yixin [Institute of Pharmacy and Pharmacology, College of Science and Technology, University of South China, Hengyang 421001, Hunan (China); Liao, Duan-fang, E-mail: dfliao66@yahoo.com.cn [Institute of Pharmacy and Pharmacology, College of Science and Technology, University of South China, Hengyang 421001, Hunan (China); Department of Traditional Chinese Diagnostics, School of Pharmacy, Hunan University of Chinese Medicine, Changsha 420108, Hunan (China)

    2010-12-03

    Research highlights: {yields} Vertical static pressure accelerates ox-LDL-induced cholesterol accumulation in cultured vascular smooth muscle cells. {yields} Static pressure induces SREBP-1 activation. {yields} Static pressure downregulates the expressions of caveolin-1 by activating SREBP-1. {yields} Static pressure also downregulates the transcription of ABCA1 by activating SREBP-1. {yields} Static pressure increases ox-LDL-induced cholesterol accumulation by SREBP-1-mediated caveolin-1 downregulation in vascular smooth muscle cells cultured in vitro. -- Abstract: Objective: To investigate the effect of static pressure on cholesterol accumulation in vascular smooth muscle cells (VSMCs) and its mechanism. Methods: Rat-derived VSMC cell line A10 treated with 50 mg/L ox-LDL and different static pressures (0, 60, 90, 120, 150, 180 mm Hg) in a custom-made pressure incubator for 48 h. Intracellular lipid droplets and lipid levels were assayed by oil red O staining and HPLC; The mRNA levels of caveolin-1 and ABCA1, the protein levels of caveolin-1 SREBP-1 and mature SREBP-1 were respectively detected by RT-PCR or western blot. ALLN, an inhibitor of SREBP metabolism, was used to elevate SREBP-1 protein level in VSMCs treated with static pressure. Results: Static pressures significantly not only increase intracellular lipid droplets in VSMCs, but also elevate cellular lipid content in a pressure-dependent manner. Intracellular free cholesterol (FC), cholesterol ester (CE), total cholesterol (TC) were respectively increased from 60.5 {+-} 2.8 mg/g, 31.8 {+-} 0.7 mg/g, 92.3 {+-} 2.1 mg/g at atmosphere pressure (ATM, 0 mm Hg) to 150.8 {+-} 9.4 mg/g, 235.9 {+-} 3.0 mg/g, 386.7 {+-} 6.4 mg/g at 180 mm Hg. At the same time, static pressures decrease the mRNA and protein levels of caveolin-1, and induce the activation and nuclear translocation of SREBP-1. ALLN increases the protein level of mature SREBP-1 and decreases caveolin-1 expression, so that cellular lipid levels were

  11. Caveolin-1-mediated post-transcriptional regulation of inducible nitric oxide synthase in human colon carcinoma cells

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    EMANUELA FELLEY-BOSCO

    2002-01-01

    Full Text Available Reactive oxygen species are now widely recognized as important players contributing both to cell homeostasis and the development of disease. In this respect nitric oxide (NO is no exception. The discussion here will center on regulation of the inducible form of nitric oxide synthase (iNOS for two reasons. First, only iNOS produces micromolar NO concentrations, amounts that are high by comparison with the picomolar to nanomolar concentrations resulting from Ca2+-controlled NO production by endothelial eNOS or neuronal nNOS. Second, iNOS is not constitutively expressed in cells and regulation of this isoenzyme, in contrast to endothelial eNOS or neuronal nNOS, is widely considered to occur at the transcriptional level only. In particular, we were interested in the possibility that caveolin-1, a protein that functions as a tumor suppressor in colon carcinoma cells (Bender et al., 2002; this issue, might regulate iNOS activity. Our results provide evidence for the existence of a post-transcriptional mechanism controlling iNOS protein levels that involves caveolin-1-dependent sequestration of iNOS within a detergent-insoluble compartment. Interestingly, despite the high degree of conservation of the caveolin-1 scaffolding domain binding motif within all NOS enzymes, the interaction detected between caveolin-1 and iNOS in vitro is crucially dependent on presence of a caveolin-1 sequence element immediately adjacent to the scaffolding domain. A model is presented summarizing the salient aspects of these results. These observations are important in the context of tumor biology, since down-regulation of caveolin-1 is predicted to promote uncontrolled iNOS activity, genotoxic damage and thereby facilitate tumor development in humans

  12. Calcium regulates caveolin-1 expression at the transcriptional level

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    Yang, Xiao-Yan; Huang, Cheng-Cheng; Kan, Qi-Ming; Li, Yan; Liu, Dan; Zhang, Xue-Cheng; Sato, Toshinori; Yamagata, Sadako; Yamagata, Tatsuya

    2012-01-01

    Highlights: ► Caveolin-1 expression is regulated by calcium signaling at the transcriptional level. ► An inhibitor of or siRNA to L-type calcium channel suppressed caveolin-1 expression. ► Cyclosporine A or an NFAT inhibitor markedly reduced caveolin-1 expression. ► Caveolin-1 regulation by calcium signaling is observed in several mouse cell lines. -- Abstract: Caveolin-1, an indispensable component of caveolae serving as a transformation suppressor protein, is highly expressed in poorly metastatic mouse osteosarcoma FBJ-S1 cells while highly metastatic FBJ-LL cells express low levels of caveolin-1. Calcium concentration is higher in FBJ-S1 cells than in FBJ-LL cells; therefore, we investigated the possibility that calcium signaling positively regulates caveolin-1 in mouse FBJ-S1 cells. When cells were treated with the calcium channel blocker nifedipine, cyclosporin A (a calcineurin inhibitor), or INCA-6 (a nuclear factor of activated T-cells [NFAT] inhibitor), caveolin-1 expression at the mRNA and protein levels decreased. RNA silencing of voltage-dependent L-type calcium channel subunit alpha-1C resulted in suppression of caveolin-1 expression. This novel caveolin-1 regulation pathway was also identified in mouse NIH 3T3 cells and Lewis lung carcinoma cells. These results indicate that caveolin-1 is positively regulated at the transcriptional level through a novel calcium signaling pathway mediated by L-type calcium channel/Ca 2+ /calcineurin/NFAT.

  13. Blockade of CD26-mediated T cell costimulation with soluble caveolin-1-Ig fusion protein induces anergy in CD4{sup +}T cells

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    Ohnuma, Kei [Department of Rheumatology and Allergy, Research Hospital, The Institute of Medical Science, The University of Tokyo, 4-6-1, Shirokanedai, Minato-ku, Tokyo 108-8639 (Japan); Division of Clinical Immunology, The Advanced Clinical Research Center, The Institute of Medical Science, The University of Tokyo, 4-6-1, Shirokanedai, Minato-ku, Tokyo 108-8639 (Japan); Uchiyama, Masahiko [Department of Rheumatology and Allergy, Research Hospital, The Institute of Medical Science, The University of Tokyo, 4-6-1, Shirokanedai, Minato-ku, Tokyo 108-8639 (Japan); Department of Computational Intelligence and System Science, Tokyo Institute of Technology, 4259 Nagatsuta-cho, Midori-ku, Yokohama, Kanagawa 226-8503 (Japan); Hatano, Ryo; Takasawa, Wataru; Endo, Yuko [Department of Rheumatology and Allergy, Research Hospital, The Institute of Medical Science, The University of Tokyo, 4-6-1, Shirokanedai, Minato-ku, Tokyo 108-8639 (Japan); Dang, Nam H. [Department of Hematologic Malignancies, Nevada Cancer Institute, Las Vegas, NV 89135 (United States); Morimoto, Chikao, E-mail: morimoto@ims.u-tokyo.ac.jp [Department of Rheumatology and Allergy, Research Hospital, The Institute of Medical Science, The University of Tokyo, 4-6-1, Shirokanedai, Minato-ku, Tokyo 108-8639 (Japan); Division of Clinical Immunology, The Advanced Clinical Research Center, The Institute of Medical Science, The University of Tokyo, 4-6-1, Shirokanedai, Minato-ku, Tokyo 108-8639 (Japan)

    2009-08-21

    CD26 binds to caveolin-1 in antigen-presenting cells (APC), and that ligation of CD26 by caveolin-1 induces T cell proliferation in a TCR/CD3-dependent manner. We report herein the effects of CD26-caveolin-1 costimulatory blockade by fusion protein caveolin-1-Ig (Cav-Ig). Soluble Cav-Ig inhibits T cell proliferation and cytokine production in response to recall antigen, or allogeneic APC. Our data hence suggest that blocking of CD26-associated signaling by soluble Cav-Ig may be an effective approach as immunosuppressive therapy.

  14. Exosome uptake depends on ERK1/2-heat shock protein 27 signaling and lipid Raft-mediated endocytosis negatively regulated by caveolin-1.

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    Svensson, Katrin J; Christianson, Helena C; Wittrup, Anders; Bourseau-Guilmain, Erika; Lindqvist, Eva; Svensson, Lena M; Mörgelin, Matthias; Belting, Mattias

    2013-06-14

    The role of exosomes in cancer can be inferred from the observation that they transfer tumor cell derived genetic material and signaling proteins, resulting in e.g. increased tumor angiogenesis and metastasis. However, the membrane transport mechanisms and the signaling events involved in the uptake of these virus-like particles remain ill-defined. We now report that internalization of exosomes derived from glioblastoma (GBM) cells involves nonclassical, lipid raft-dependent endocytosis. Importantly, we show that the lipid raft-associated protein caveolin-1 (CAV1), in analogy with its previously described role in virus uptake, negatively regulates the uptake of exosomes. We find that exosomes induce the phosphorylation of several downstream targets known to associate with lipid rafts as signaling and sorting platforms, such as extracellular signal-regulated kinase-1/2 (ERK1/2) and heat shock protein 27 (HSP27). Interestingly, exosome uptake appears dependent on unperturbed ERK1/2-HSP27 signaling, and ERK1/2 phosphorylation is under negative influence by CAV1 during internalization of exosomes. These findings significantly advance our general understanding of exosome-mediated uptake and offer potential strategies for how this pathway may be targeted through modulation of CAV1 expression and ERK1/2 signaling.

  15. Caveolin-1 expression in benign and malignant lesions of the breast

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    Kiesel Ludwig

    2007-10-01

    Full Text Available Abstract Background Caveolin-1 is thought to have an important impact on both signal transduction and mediation of intracellular processes. Furthermore, it has been suggested that Caveolin-1 may contribute to certain steps of carcinogenesis in various types of cancer. We examined the potential clinical relevance of Caveolin-1 in normal, benign and malignant breast tissue specimens. Methods Using tissue microarray (TMA technology cases of invasive breast cancer, DCIS, benign breast disease (i.e. fibroadenoma, sclerosing adenosis, ductal hyperplasia and radial scar and normal breast tissue were evaluated for Caveolin-1 expression. Immunohistochemical staining with an anti-Caveolin-1-antibody was performed. Staining intensity was quantified semiquantitatively. In invasive lesions staining results were correlated with clinical and pathological data. Results No Caveolin-1 expression was observed in epithelial cells of normal breast tissue (n = 5, benign breast disease (n = 295 and DCIS (n = 108. However, Caveolin-1 expression was found in 32 of 109 cases of invasive breast carcinomas (29.4%. Caveolin-1 expression in invasive breast cancer could neither be correlated with survival parameters such as overall or disease-free survival nor with established clinical and pathological markers. Conclusion In this study we demonstrated expression of Caveolin-1 in one third of invasive breast cancers. A significant increase in Caveolin-1 expression was observed comparing invasive breast cancer to both benign breast tissue and non-invasive breast cancer. Since inhibitors of Caveolin-1 signalling are available, targeting Caveolin-1 in breast cancer may represent a potential option for future breast cancer treatment.

  16. AKT-mediated enhanced aerobic glycolysis causes acquired radioresistance by human tumor cells

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    Shimura, Tsutomu; Noma, Naoto; Sano, Yui; Ochiai, Yasushi; Oikawa, Toshiyuki; Fukumoto, Manabu; Kunugita, Naoki

    2014-01-01

    Background and purpose: Cellular radioresistance is a major impediment to effective radiotherapy. Here, we demonstrated that long-term exposure to fractionated radiation conferred acquired radioresistance to tumor cells due to AKT-mediated enhanced aerobic glycolysis. Material and methods: Two human tumor cell lines with acquired radioresistance were established by long-term exposure to fractionated radiation with 0.5 Gy of X-rays. Glucose uptake was inhibited using 2-deoxy-D-glucose, a non-metabolizable glucose analog. Aerobic glycolysis was assessed by measuring lactate concentrations. Cells were then used for assays of ROS generation, survival, and cell death as assessed by annexin V staining. Results: Enhanced aerobic glycolysis was shown by increased glucose transporter Glut1 expression and a high lactate production rate in acquired radioresistant cells compared with parental cells. Inhibiting the AKT pathway using the AKT inhibitor API-2 abrogated these phenomena. Moreover, we found that inhibiting glycolysis with 2-deoxy-D-glucose suppressed acquired tumor cell radioresistance. Conclusions: Long-term fractionated radiation confers acquired radioresistance to tumor cells by AKT-mediated alterations in their glucose metabolic pathway. Thus, tumor cell metabolic pathway is an attractive target to eliminate radioresistant cells and improve radiotherapy efficacy

  17. miR-199a-5p Is upregulated during fibrogenic response to tissue injury and mediates TGFbeta-induced lung fibroblast activation by targeting caveolin-1.

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    Christian Lacks Lino Cardenas

    Full Text Available As miRNAs are associated with normal cellular processes, deregulation of miRNAs is thought to play a causative role in many complex diseases. Nevertheless, the precise contribution of miRNAs in fibrotic lung diseases, especially the idiopathic form (IPF, remains poorly understood. Given the poor response rate of IPF patients to current therapy, new insights into the pathogenic mechanisms controlling lung fibroblasts activation, the key cell type driving the fibrogenic process, are essential to develop new therapeutic strategies for this devastating disease. To identify miRNAs with potential roles in lung fibrogenesis, we performed a genome-wide assessment of miRNA expression in lungs from two different mouse strains known for their distinct susceptibility to develop lung fibrosis after bleomycin exposure. This led to the identification of miR-199a-5p as the best miRNA candidate associated with bleomycin response. Importantly, miR-199a-5p pulmonary expression was also significantly increased in IPF patients (94 IPF versus 83 controls. In particular, levels of miR-199a-5p were selectively increased in myofibroblasts from injured mouse lungs and fibroblastic foci, a histologic feature associated with IPF. Therefore, miR-199a-5p profibrotic effects were further investigated in cultured lung fibroblasts: miR-199a-5p expression was induced upon TGFβ exposure, and ectopic expression of miR-199a-5p was sufficient to promote the pathogenic activation of pulmonary fibroblasts including proliferation, migration, invasion, and differentiation into myofibroblasts. In addition, we demonstrated that miR-199a-5p is a key effector of TGFβ signaling in lung fibroblasts by regulating CAV1, a critical mediator of pulmonary fibrosis. Remarkably, aberrant expression of miR-199a-5p was also found in unilateral ureteral obstruction mouse model of kidney fibrosis, as well as in both bile duct ligation and CCl4-induced mouse models of liver fibrosis, suggesting that

  18. Up-regulation of integrin β3 in radioresistant pancreatic cancer impairs adenovirus-mediated gene therapy

    International Nuclear Information System (INIS)

    Egami, Takuya; Ohuchida, Kenoki; Yasui, Takaharu; Onimaru, Manabu; Toma, Hiroki; Sato, Norihiro; Tanaka, Masao; Mizumoto, Kazuhiro; Matsumoto, Kunio

    2009-01-01

    Adenovirus-mediated gene therapy is a promising approach for the treatment of pancreatic cancer. We previously reported that radiation enhanced adenovirus-mediated gene expression in pancreatic cancer, suggesting that adenoviral gene therapy might be more effective in radioresistant pancreatic cancer cells. In the present study, we compared the transduction efficiency of adenovirus-delivered genes in radiosensitive and radioresistant cells, and investigated the underlying mechanisms. We used an adenovirus expressing the hepatocyte growth factor antagonist, NK4 (Ad-NK4), as a representative gene therapy. We established two radioresistant human pancreatic cancer cell lines using fractionated irradiation. Radiosensitive and radioresistant pancreatic cancer cells were infected with Ad-NK4, and NK4 levels in the cells were measured. In order to investigate the mechanisms responsible for the differences in the transduction efficiency between these cells, we measured expression of the genes mediating adenovirus infection and endocytosis. The results revealed that NK4 levels in radioresistant cells were significantly lower (P<0.01) than those in radiosensitive cells, although there were no significant differences in adenovirus uptake between radiosensitive cells and radioresistant cells. Integrin β3 was up-regulated and the Coxsackie virus and adenovirus receptor was down-regulated in radioresistant cells, and inhibition of integrin β3 promoted adenovirus gene transfer. These results suggest that inhibition of integrin β3 in radioresistant pancreatic cancer cells could enhance adenovirus-mediated gene therapy. (author)

  19. Hypoxia-inducible factor 1–mediated characteristic features of cancer cells for tumor radioresistance

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    Harada, Hiroshi

    2016-01-01

    Tumor hypoxia has been attracting increasing attention in the fields of radiation biology and oncology since Thomlinson and Gray detected hypoxic cells in malignant solid tumors and showed that they exert a negative impact on the outcome of radiation therapy. This unfavorable influence has, at least partly, been attributed to cancer cells acquiring a radioresistant phenotype through the activation of the transcription factor, hypoxia-inducible factor 1 (HIF-1). On the other hand, accumulating evidence has recently revealed that, even though HIF-1 is recognized as an important regulator of cellular adaptive responses to hypoxia, it may not become active and induce tumor radioresistance under hypoxic conditions only. The mechanisms by which HIF-1 is activated in cancer cells not only under hypoxic conditions, but also under normoxic conditions, through cancer-specific genetic alterations and the resultant imbalance in intermediate metabolites have been summarized herein. The relevance of the HIF-1–mediated characteristic features of cancer cells, such as the production of antioxidants through reprogramming of the glucose metabolic pathway and cell cycle regulation, for tumor radioresistance has also been reviewed

  20. Polychlorinated biphenyl-induced VCAM-1 expression is attenuated in aortic endothelial cells isolated from caveolin-1 deficient mice

    International Nuclear Information System (INIS)

    Han, Sung Gu; Eum, Sung Yong; Toborek, Michal; Smart, Eric; Hennig, Bernhard

    2010-01-01

    Exposure to environmental contaminants, such as polychlorinated biphenyls (PCBs), is a risk factor for the development of cardiovascular diseases such as atherosclerosis. Vascular cell adhesion molecule-1 (VCAM-1) is a critical mediator for adhesion and uptake of monocytes across the endothelium in the early stages of atherosclerosis development. The upregulation of VCAM-1 by PCBs may be dependent on functional membrane domains called caveolae. Caveolae are particularly abundant in endothelial cell membranes and involved in trafficking and signal transduction. The objective of this study was to investigate the role of caveolae in PCB-induced endothelial cell dysfunction. Primary mouse aortic endothelial cells (MAECs) isolated from caveolin-1-deficient mice and background C57BL/6 mice were treated with coplanar PCBs, such as PCB77 and PCB126. In addition, siRNA gene silencing technique was used to knockdown caveolin-1 in porcine vascular endothelial cells. In MAECs with functional caveolae, VCAM-1 protein levels were increased after exposure to both coplanar PCBs, whereas expression levels of VCAM-1 were not significantly altered in cells deficient of caveolin-1. Furthermore, PCB-induced monocyte adhesion was attenuated in caveolin-1-deficient MAECs. Similarly, siRNA silencing of caveolin-1 in porcine endothelial cells confirmed the caveolin-1-dependent VCAM-1 expression. Treatment of cells with PCB77 and PCB126 resulted in phosphorylation of extracellular signal-regulated kinase-1/2 (ERK1/2), and pharmacological inhibition of ERK1/2 diminished the observed PCB-induced increase in monocyte adhesion. These findings suggest that coplanar PCBs induce adhesion molecule expression, such as VCAM-1, in endothelial cells, and that this response is regulated by caveolin-1 and functional caveolae. Our data demonstrate a critical role of functional caveolae in the activation and dysfunction of endothelial cells by coplanar PCBs.

  1. Caveolin-1 expression in odontogenic cysts and ameloblastomas.

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    Jaafari-Ashkavandi, Zohreh; Pardis, Soheil; Asadzadeh, Maryam; Andisheh-Tadbir, Azadeh; Dehghani-Nazhvani, Ali

    2014-01-01

    The aim of this study is to evaluate the caveolin-1 expression in a group of odontogenic cysts and tumors. In this cross-sectional study, the expression of caveolin-1 was evaluated immunohistochemically in 75 samples including 18 cases of dentigerous cyst, 18 odontogenic keratocysts, 3 orthokeratinized odontogenic cysts, 2 calcifying odontogenic cysts and 34 ameloblastomas (solid and unicystic). Positive immunohistochemical reaction was found in 100% of odontogenic cysts and this was significantly more than both unicystic (65%) and solid (55%) ameloblastomas. The present study showed the expression of caveolin-1 in all odontogenic cysts and more than ameloblastomas. The results suggested that absence of caveolin-1 might enhance aggressiveness of odontogenic lesions and could be a useful marker for distinguishing ameloblastomas from other odontogenic lesions.

  2. Overexpression of caveolin-1 in lymphoblastoid TK6 cells enhances proliferation after irradiation with clinically relevant doses

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    Barzan, David; Maier, Patrick; Wenz, Frederik; Herskind, Carsten [Dept. of Radiation Oncology, Univ. Medical Center Mannheim, Univ. of Heidelberg, Mannheim (Germany); Zeller, W. Jens [Pharmacology of Cancer Treatment, German Cancer Research Center, Heidelberg (Germany)

    2010-02-15

    Background and Purpose: The transmembrane protein caveolin-1 (CAV1) is an essential component of caveolae, small membrane invaginations involved in vesicle formation. CAV1 plays a role in signal transduction, tumor suppression and oncogene transformation. Previous studies with CAV1 knockout mice and CAV1 knockdown in pancreatic tumor cells implicated CAV1 in mediating radioresistance. The aim of this work was to test the effect of CAV1 overexpression after irradiation in human cells lacking endogenous CAV1 expression. Material and Methods: Human CAV1 was overexpressed in lymphoblastoid TK6 cells (TK6-wt) using a eukaryotic expression plasmid, pCI-CAV1, or a lentiviral SIN (self-inactivating) vector, HR'SIN-CAV1. CAV1 expression was verified in TK6 cells with Western blot analysis or intracellular FACS (fluorescence-activated cell sorting) staining. The effect of CAV1 on proliferation kinetics after irradiation of TK6 cells was measured with a growth assay. Results: TK6-wt showed no detectable endogenous CAV1 expression. Lentivirally mediated transduction with HR'SIN-CAV1 (TK6-CAV1) resulted in a considerably stronger CAV1 expression in comparison to TK6 cells electroporated with pCI-CAV1. Intracellular FACS analysis showed that 90% of transduced cells expressed CAV1. CAV1 enhanced early proliferation of TK6 cells after irradiation with a dose of 2 Gy, whereas proliferation of unirradiated cells was not affected. CAV1 also protected cells after irradiation with 4 Gy. This radioprotective effect was supported by a reduction of radiation-induced apoptosis. Conclusion: A model system for expression of exogenous CAV1 by stable lentiviral transduction of TK6 cells was established. Functional assays demonstrated enhanced early proliferation by CAV1 expression in TK6 cells after irradiation with clinically relevant doses supporting the role of CAV1 as a prosurvival factor. (orig.)

  3. Overexpression of caveolin-1 in lymphoblastoid TK6 cells enhances proliferation after irradiation with clinically relevant doses

    International Nuclear Information System (INIS)

    Barzan, David; Maier, Patrick; Wenz, Frederik; Herskind, Carsten; Zeller, W. Jens

    2010-01-01

    Background and Purpose: The transmembrane protein caveolin-1 (CAV1) is an essential component of caveolae, small membrane invaginations involved in vesicle formation. CAV1 plays a role in signal transduction, tumor suppression and oncogene transformation. Previous studies with CAV1 knockout mice and CAV1 knockdown in pancreatic tumor cells implicated CAV1 in mediating radioresistance. The aim of this work was to test the effect of CAV1 overexpression after irradiation in human cells lacking endogenous CAV1 expression. Material and Methods: Human CAV1 was overexpressed in lymphoblastoid TK6 cells (TK6-wt) using a eukaryotic expression plasmid, pCI-CAV1, or a lentiviral SIN (self-inactivating) vector, HR'SIN-CAV1. CAV1 expression was verified in TK6 cells with Western blot analysis or intracellular FACS (fluorescence-activated cell sorting) staining. The effect of CAV1 on proliferation kinetics after irradiation of TK6 cells was measured with a growth assay. Results: TK6-wt showed no detectable endogenous CAV1 expression. Lentivirally mediated transduction with HR'SIN-CAV1 (TK6-CAV1) resulted in a considerably stronger CAV1 expression in comparison to TK6 cells electroporated with pCI-CAV1. Intracellular FACS analysis showed that 90% of transduced cells expressed CAV1. CAV1 enhanced early proliferation of TK6 cells after irradiation with a dose of 2 Gy, whereas proliferation of unirradiated cells was not affected. CAV1 also protected cells after irradiation with 4 Gy. This radioprotective effect was supported by a reduction of radiation-induced apoptosis. Conclusion: A model system for expression of exogenous CAV1 by stable lentiviral transduction of TK6 cells was established. Functional assays demonstrated enhanced early proliferation by CAV1 expression in TK6 cells after irradiation with clinically relevant doses supporting the role of CAV1 as a prosurvival factor. (orig.)

  4. Androgen Receptor Localizes to Plasma Membrane by Binding to Caveolin-1 in Mouse Sertoli Cells

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    Qiong Deng

    2017-01-01

    Full Text Available The nonclassical androgen signaling pathway translates signals into alterations in cellular function within minutes, and this action is proposed to be mediated by an androgen receptor (AR localized to the plasma membrane. This study was designed to determine the mechanism underlying the membrane association of androgen receptor in TM4 cells, a mouse Sertoli cell line. Western blot analysis indicated testosterone-induced AR translocation to the cell membrane. Data from coimmunoprecipitation indicated that AR is associated with caveolin-1, and testosterone enhanced this association. Knockdown of caveolin-1 by shRNA decreased the amount of AR localized to membrane fraction and prevented AR membrane trafficking after being exposed to testosterone at physiological concentration. The palmitoylation inhibitor 2-bromopalmitate decreased AR membrane localization in basal condition and completely blocked testosterone-induced AR translocation to membrane fraction. These data suggested that AR localized to membrane fraction by binding with caveolin-1 through palmitoylation of the cysteine residue. This study provided a new evidence for AR membrane localization and its application for clarifying the nonclassical signaling pathway of androgens.

  5. Caveolar fatty acids and acylation of caveolin-1.

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    Qian Cai

    Full Text Available Caveolae are cholesterol and sphingolipids rich subcellular domains on plasma membrane. Caveolae contain a variety of signaling proteins which provide platforms for signaling transduction. In addition to enriched with cholesterol and sphingolipids, caveolae also contain a variety of fatty acids. It has been well-established that acylation of protein plays a pivotal role in subcellular location including targeting to caveolae. However, the fatty acid compositions of caveolae and the type of acylation of caveolar proteins remain largely unknown. In this study, we investigated the fatty acids in caveolae and caveolin-1 bound fatty acids.Caveolae were isolated from Chinese hamster ovary (CHO cells. The caveolar fatty acids were extracted with Folch reagent, methyl esterificated with BF3, and analyzed by gas chromatograph-mass spectrometer (GC/MS. The caveolin-1 bound fatty acids were immunoprecipitated by anti-caveolin-1 IgG and analyzed with GC/MS.In contrast to the whole CHO cell lysate which contained a variety of fatty acids, caveolae mainly contained three types of fatty acids, 0.48 µg palmitic acid, 0.61 µg stearic acid and 0.83 µg oleic acid/caveolae preparation/5 × 10(7 cells. Unexpectedly, GC/MS analysis indicated that caveolin-1 was not acylated by myristic acid; instead, it was acylated by palmitic acid and stearic acid.Caveolae contained a special set of fatty acids, highly enriched with saturated fatty acids, and caveolin-1 was acylated by palmitic acid and stearic acid. The unique fatty acid compositions of caveolae and acylation of caveolin-1 may be important for caveolae formation and for maintaining the function of caveolae.

  6. Association between Caveolin-1 expression and pathophysiological progression of femoral nerves in diabetic foot amputation patients

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    Ding Min

    2017-10-01

    Full Text Available To evaluate the pathological changes of femoral nerves and the levels of caveolin-1 in diabetic foot amputation patients with neuropathy, and evaluate the association between caveolin-1 and neuropathy development.

  7. Inter-domain tagging implicates caveolin-1 in insulin receptor trafficking and Erk signaling bias in pancreatic beta-cells

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    Tobias Boothe

    2016-05-01

    Full Text Available Objective: The role and mechanisms of insulin receptor internalization remain incompletely understood. Previous trafficking studies of insulin receptors involved fluorescent protein tagging at their termini, manipulations that may be expected to result in dysfunctional receptors. Our objective was to determine the trafficking route and molecular mechanisms of functional tagged insulin receptors and endogenous insulin receptors in pancreatic beta-cells. Methods: We generated functional insulin receptors tagged with pH-resistant fluorescent proteins between domains. Confocal, TIRF and STED imaging revealed a trafficking pattern of inter-domain tagged insulin receptors and endogenous insulin receptors detected with antibodies. Results: Surprisingly, interdomain-tagged and endogenous insulin receptors in beta-cells bypassed classical Rab5a- or Rab7-mediated endocytic routes. Instead, we found that removal of insulin receptors from the plasma membrane involved tyrosine-phosphorylated caveolin-1, prior to trafficking within flotillin-1-positive structures to lysosomes. Multiple methods of inhibiting caveolin-1 significantly reduced Erk activation in vitro or in vivo, while leaving Akt signaling mostly intact. Conclusions: We conclude that phosphorylated caveolin-1 plays a role in insulin receptor internalization towards lysosomes through flotillin-1-positive structures and that caveolin-1 helps bias physiological beta-cell insulin signaling towards Erk activation. Author Video: Author Video Watch what authors say about their articles Keywords: Insulin receptor internalization, Insulin resistance, Pancreatic islet beta-cells, Autocrine insulin signaling

  8. The phosphatidylinositol-3 kinase pathway is not essential for insulin-like growth factor I receptor-mediated clonogenic radioresistance

    International Nuclear Information System (INIS)

    Yu, Dong; Watanabe, Hiroshi; Shibuya, Hitoshi; Miura, Masahiko

    2002-01-01

    The insulin-like growth factor I receptor (IGF-IR) is known to induce clonogenic radioresistance in cells following ionizing irradiation. To explore the downstream signaling pathways, we focused on the phosphatidylinositol-3 kinase (PI3-K) pathway, which is thought to be the primary cell survival signal originating from the receptor. For this purpose, R- cells deficient in the endogenous IGF-IR were used as a recipient of the human IGF-IR with or without mutations at potential PI3-K activation sites: NPXY 950 and Y 1316 XXM. Mutats with double mutation at Y950/Y1316 exhibited not abrogated, but reduced activation of insulin receptor substance-1 (IRS-1), PI3-K, and Akt upon IGF-I stimulation. However, the mutants had the same clonogenic radioresistance as cells with wild type (WT) receptors. Neither wortmannin nor LY294002, specific inhibitors of PI3-K, affected the radioresistance of cells with WT receptors at concentrations specific for PI3-K. Collectively, these results indicate that the PI3-K pathway is not essential for IGF-IR-mediated clonogenic radioresistance. (author)

  9. Microparticle-Induced Activation of the Vascular Endothelium Requires Caveolin-1/Caveolae.

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    Allison M Andrews

    Full Text Available Microparticles (MPs are small membrane fragments shed from normal as well as activated, apoptotic or injured cells. Emerging evidence implicates MPs as a causal and/or contributing factor in altering normal vascular cell phenotype through initiation of proinflammatory signal transduction events and paracrine delivery of proteins, mRNA and miRNA. However, little is known regarding the mechanism by which MPs influence these events. Caveolae are important membrane microdomains that function as centers of signal transduction and endocytosis. Here, we tested the concept that the MP-induced pro-inflammatory phenotype shift in endothelial cells (ECs depends on caveolae. Consistent with previous reports, MP challenge activated ECs as evidenced by upregulation of intracellular adhesion molecule-1 (ICAM-1 expression. ICAM-1 upregulation was mediated by activation of NF-κB, Poly [ADP-ribose] polymerase 1 (PARP-1 and the epidermal growth factor receptor (EGFR. This response was absent in ECs lacking caveolin-1/caveolae. To test whether caveolae-mediated endocytosis, a dynamin-2 dependent process, is a feature of the proinflammatory response, EC's were pretreated with the dynamin-2 inhibitor dynasore. Similar to observations in cells lacking caveolin-1, inhibition of endocytosis significantly attenuated MPs effects including, EGFR phosphorylation, activation of NF-κB and upregulation of ICAM-1 expression. Thus, our results indicate that caveolae play a role in mediating the pro-inflammatory signaling pathways which lead to EC activation in response to MPs.

  10. Caveolin-1 influences human influenza A virus (H1N1 multiplication in cell culture

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    Hemgård Gun-Viol

    2010-05-01

    Full Text Available Abstract Background The threat of recurring influenza pandemics caused by new viral strains and the occurrence of escape mutants necessitate the search for potent therapeutic targets. The dependence of viruses on cellular factors provides a weak-spot in the viral multiplication strategy and a means to interfere with viral multiplication. Results Using a motif-based search strategy for antiviral targets we identified caveolin-1 (Cav-1 as a putative cellular interaction partner of human influenza A viruses, including the pandemic influenza A virus (H1N1 strains of swine origin circulating from spring 2009 on. The influence of Cav-1 on human influenza A/PR/8/34 (H1N1 virus replication was determined in inhibition and competition experiments. RNAi-mediated Cav-1 knock-down as well as transfection of a dominant-negative Cav-1 mutant results in a decrease in virus titre in infected Madin-Darby canine kidney cells (MDCK, a cell line commonly used in basic influenza research as well as in virus vaccine production. To understand the molecular basis of the phenomenon we focussed on the putative caveolin-1 binding domain (CBD located in the lumenal, juxtamembranal portion of the M2 matrix protein which has been identified in the motif-based search. Pull-down assays and co-immunoprecipitation experiments showed that caveolin-1 binds to M2. The data suggest, that Cav-1 modulates influenza virus A replication presumably based on M2/Cav-1 interaction. Conclusion As Cav-1 is involved in the human influenza A virus life cycle, the multifunctional protein and its interaction with M2 protein of human influenza A viruses represent a promising starting point for the search for antiviral agents.

  11. Hepatitis B virus X protein suppresses caveolin-1 expression in hepatocellular carcinoma by regulating DNA methylation

    International Nuclear Information System (INIS)

    Yan, Jun; Lu, Qian; Dong, Jiahong; Li, Xiaowu; Ma, Kuansheng; Cai, Lei

    2012-01-01

    To understand the molecular mechanisms of caveolin-1 downregulation by hepatitis B virus X protein (HBx). The DNA methylation status of the caveolin-1 promoter was examined by nested methylation-specific PCR of 33 hepatitis B virus (HBV)-infected hepatocellular carcinoma (HCC) samples. The SMMC-7721 hepatoma cell line was transfected with a recombinant HBx adenoviral vector, and the effects of HBx protein on caveolin-1 expression and promoter methylation were examined and confirmed by sequencing. A reporter gene containing the caveolin-1 promoter region was constructed, and the effects of HBx on the transcriptional activity of the promoter were also studied. Methylation of the caveolin-1 promoter was detected in 84.8% (28/33) of HBV-infected HCC samples. Expression of caveolin-1 was significantly downregulated (P = 0.022), and multiple CpG sites in the promoter region of caveolin-1 were methylated in SMMC-7721 cells after HBx transfection. Transfected HBx significantly suppressed caveolin-1 promoter activity (P = 0.001). HBx protein induces methylation of the caveolin-1 promoter region and suppresses its expression

  12. Caveolin-1 overexpression in benign and malignant salivary gland tumors.

    Science.gov (United States)

    Jaafari-Ashkavandi, Zohreh; Ashraf, Mohammad Javad; Nazhvani, Ali Dehghani; Azizi, Zahra

    2016-02-01

    Caveolin-1, a tyrosine-phosphorylated protein, is supposed to have different regulatory roles as promoter or suppressor in many human cancers. However, no published study concerned its expression in benign and malignant salivary gland tumors. The aim of this study was to evaluate and compare the expression of Cav-1 in the most common benign and malignant salivary gland tumors and evaluate its correlation with proliferation activity. In this cross-sectional retrospective study, immunohistochemical expression of caveolin-1 and Ki67 were evaluated in 49 samples, including 11 normal salivary glands, 15 cases of pleomorphic adenoma (PA), 13 adenoid cystic carcinomas (AdCC), and 10 mucoepidermoid carcinomas (MEC). The expression of Cav-1 was seen in 18 % of normal salivary glands and 85 % of tumors. The immunoreaction in the tumors was significantly higher than normal tissues (P = 0.001), but the difference between benign and malignant tumors was not significant (P = 0.07). Expression of Cav-1 was correlated with Ki67 labeling index in PAs, but not in malignant tumors. Cav-1 expression was not in association with tumor size and stage. Overexpression of Cav-1 was found in salivary gland tumors in comparison with normal tissues, but no significant difference was observed between benign and malignant tumors. Cav-1 was inversely correlated with proliferation in PA. Therefore, this marker may participate in tumorigenesis of salivary gland tumors and may be a potential biomarker for cancer treatments.

  13. Impairment of the vascular relaxation and differential expression of caveolin-1 of the aorta of diabetic +db/+db mice.

    Science.gov (United States)

    Lam, Tze Yan; Seto, Sai Wang; Lau, Yee Man; Au, Lai Shan; Kwan, Yiu Wa; Ngai, Sai Ming; Tsui, Kwong Wing

    2006-09-28

    In this study, we compared the endothelium-dependent and -independent relaxation of the isolated thoracic aorta of control (+db/+m) and diabetic (+db/+db) (C57BL/KsJ) mice. The gene expression (mRNA and protein) level of the muscarinic M(3) receptors, endothelial nitric oxide synthase (eNOS) and caveolin-1 of the aorta was also evaluated. Acetylcholine caused a concentration-dependent, N(G)-nitro-L-arginine methyl-ester (20 microM)-sensitive relaxation, with approximately 100% relaxation at 10 microM, in +db/+m mice. In +db/+db mice, the acetylcholine-induced relaxation was significantly smaller (maximum relaxation: approximately 80%). The sodium nitroprusside-mediated relaxation was slightly diminished in +db/+db mice, compared to +db/+m mice. However, there was no significant difference in the isoprenaline- and cromakalim-induced relaxation observed in both species. The mRNA and protein expression levels of caveolin-1 were significantly higher in the aorta of +db/+db mice. In contrast, there was no difference in the mRNA and protein expression levels of eNOS and muscarinic M(3) receptors between these mice. Our results demonstrate that the impairment of the acetylcholine-induced, endothelium-dependent aortic relaxation observed in +db/+db mice was probably associated with an enhanced expression of caveolin-1 mRNA and protein.

  14. Spatiotemporal expression of caveolin-1 and EMMPRIN during mouse tooth development.

    Science.gov (United States)

    Shi, Lu; Li, Lingyun; Wang, Ding; Li, Shu; Chen, Zhi; An, Zhengwen

    2016-06-01

    Caveolin-1 is a scaffolding protein involved in the formation of cholesterol-rich caveolae lipid rafts within the plasma membrane and is capable of collecting signaling molecules into the caveolae and regulating their activity, including extracellular matrix metalloproteinase inducer (EMMPRIN). However, detailed expression patterns of caveolin-1 and EMMPRIN in the developing dental germ are largely unknown. The present study investigated the expression patterns of caveolin-1 and EMMPRIN in the developing mouse tooth germ by immunohistochemistry and real-time polymerase chain reaction. At the bud stage, caveolin-1 expression was initiated in the epithelium bud and mesenchymal cells, while EMMPRIN was weakly expressed at this stage. At the cap stage, caveolin-1 protein was located in the lingual part of the tooth germ; however, EMMPRIN protein was located in the labial part. From the bell stage to 2 days postnatal, caveolin-1 expression was detected in the ameloblasts and cervical loop area; with EMMPRIN expression in the ameloblasts and odontoblasts. Real-time polymerase chain reaction results showed that both caveolin-1 and EMMPRIN mRNA levels increased gradually with progression of developmental stages, and peaked at day two postnatal. The current finding suggests that both caveolin-1 and EMMPRIN take part in mouse tooth development, especially in the differentiation and organization of odontogenic tissues.

  15. Caveolin-1 as a novel indicator of wound-healing capacity in aged human corneal epithelium.

    Science.gov (United States)

    Rhim, Ji Heon; Kim, Jae Hoon; Yeo, Eui-Ju; Kim, Jae Chan; Park, Sang Chul

    2010-01-01

    Excess caveolin-1 has been reported to play a role in age-dependent hyporesponsiveness to growth factors in vitro. Therefore, we hypothesized that caveolin-1-dependent hyporesponsiveness to growth factors in aged corneal epithelial cells might be responsible for delayed wound healing in vivo. To test this hypothesis, we evaluated corneal wound-healing time by vital staining using fluorescein after laser epithelial keratomileusis (LASEK). We compared wound-healing times in young, middle-aged and elderly patients. We also examined caveolin-1 levels and other aging markers, such as p53 and p21, in the corneal epithelium. Elderly patients generally had higher caveolin-1 levels in the corneal epithelia than young patients. There were, however, variations among individuals with increased caveolin-1 in some young patients and decreased levels in some elderly patients. Wound-healing time after LASEK correlated well with the corneal caveolin-1 status. Therefore, we suggest that caveolin-1 status might be responsible for delayed wound healing in elderly patients after LASEK. Caveolin-1 status might be a regulator for wound-healing capacity and a novel target for in vivo adjustment.

  16. Reprogramming mediated radio-resistance of 3D-grown cancer cells

    International Nuclear Information System (INIS)

    Xue Gang; Ren Zhenxin; Chen Yaxiong; Zhu Jiayun; Du Yarong; Pan Dong; Li Xiaoman; Hu Burong; Grabham, Peter W.

    2015-01-01

    In vitro 3D growth of tumors is a new cell culture model that more closely mimics the features of the in vivo environment and is being used increasingly in the field of biological and medical research. It has been demonstrated that cancer cells cultured in 3D matrices are more radio-resistant compared with cells in monolayers. However, the mechanisms causing this difference remain unclear. Here we show that cancer cells cultured in a 3D microenvironment demonstrated an increase in cells with stem cell properties. This was confirmed by the finding that cells in 3D cultures upregulated the gene and protein expression of the stem cell reprogramming factors such as OCT4, SOX2, NANOG, LIN28 and miR-302a, compared with cells in monolayers. Moreover, the expression of β-catenin, a regulating molecule of reprogramming factors, also increased in 3D-grown cancer cells. These findings suggest that cancer cells were reprogrammed to become stem cell-like cancer cells in a 3D growth culture microenvironment. Since cancer stem cell-like cells demonstrate an increased radio-resistance and chemo-resistance, our results offer a new perspective as to why. Our findings shed new light on understanding the features of the 3D growth cell model and its application in basic research into clinical radiotherapy and medicine. (author)

  17. Suppression of in vitro cell-mediated lympholysis generation by alloactivated lymphocytes. Examination of radioresistant suppressive activity

    International Nuclear Information System (INIS)

    Orosz, C.G.; Ferguson, R.M.

    1986-01-01

    We investigated the radioresistant (1000 rads) suppression of CML generation mediated by alloactivated murine splenocytes. Suppressive cells were generated in MLCs by stimulation of (A X 6R)F1 splenocytes with irradiated C57BL/10 splenocytes. Suppressive cells could lyse targets bearing H-2b alloantigens, but would not lyse parental B10.T(6R) or B10.A targets. Suppressive activity was detected by including the alloactivated (A X 6R)F1 cells in B10.T(6R) anti-B10.A(1R) MLCs. Relative to the suppressive (A X 6R)F1 cells, the B10.A(1R) lymphocytes display both parental and suppressor-inducing alloantigens. In the absence of a suppressive population, B10.A(1R) stimulators cause B10.T(6R) splenocytes to generate cytolytic activity specific for both H-2Db (suppressor-inducing) and H-2Kk (suppressor-borne) target determinants. The irradiated, alloactivated (A X 6R)F1 cells decrease the H-2Db-specific CML generated in this system, thus mediating apparent antigen-specific suppression. However, cytolytic activity concomitantly generated in the same culture against the unrelated H-2Kk target determinants is similarly reduced by the (A X 6R)F1 cells. Thus, radioresistant suppression by alloactivated splenocytes is not necessarily antigen-specific. The irradiated (A X 6R)F1 cells would not suppress the generation of H-2Kk-specific CTL in B10.T(6R) anti-B10.A MLCs. Hence, the irradiated (A X 6R)F1 cells can impede CML generation against third-party alloantigens if, and only if, those alloantigens are coexpressed with suppressor-inducing alloantigens on the stimulator cells in suppressed MLCs. Similar results were also obtained using a different histoincompatible lymphocyte combination

  18. [Cloning and characterization of Caveolin-1 gene in pigeon, Columba livia domestica].

    Science.gov (United States)

    Zhang, Ying; Yu, Jian-Feng; Yang, Li; Wang, Xing-Guo; Gu, Zhi-Liang

    2010-10-01

    Caveolins, a class of principal proteins forming the structure of caveolae in plasmalemma, were encoded by caveolins gene family. Caveolin-1 gene is a member of caveolins gene family. In the present study, a full-length of 2605 bp caveolin-1 cDNA sequence in Columba livia domestica, which included a 537 bp complete ORF encoding a 178 amino acids long putative peptide, were obtained by using RT-PCR and RACE technique. The Columba livia domestica caveolin-1 CDS shared 80.1% - 93.4% homology with Bos taurus, Canis lupus familiaris, Gallus gallus and Rattus norvegicus. Meanwhile, the putative amino acid sequence of Columba livia domestica caveolin-1 shared 85.4% - 97.2% homology with the above species. The semi-quantity RT-PCR revealed that Caveolin-1 expressions were detectable in all the Columba livia domestica tissues and the expressional level of caveolin-1 gene was high in adipose, medium in various muscles, low in liver. These results demonstrated that Caveolin-1 gene was potentially involved in some metabolic pathways in adipose and muscle.

  19. Caveolin-1 Expression in Thyroid Neoplasia Spectrum: Comparison of Two Commercial Antibodies

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    Jelena Janković

    2012-01-01

    Full Text Available We evaluated caveolin-1 expression in the human thyroid neoplasia spectrum with the aim of examining differences in expression as detected by two anti-caveolin-1 antibodies, and secondly, to investigate the association of caveolin-1 expression levels with aggressive papillary thyroid carcinoma (PTC. Immunohistochemical staining using sc894 or AV09019 antibodies revealed that caveolin-1 was generally overexpressed in the PTC group as a whole (classical and follicular variant when compared to peritumoral tissue (PT, while it was not detected in about half of follicular thyroid carcinoma (FTC and majority of follicular adenomas (FTA. Caveolin-1 expression decreased in the following order: clPTC, fvPTC, FTC, PT and FTA. The diagnostic accuracy of AV09019 was better than that of sc894 for discriminating: FTA from FTC, FTA or FTC from the follicular variant of PTC, total PTC from nonmalignant tissue, and malignant tumors from nonmalignant tissue. Spearman's analysis revealed positive correlations of caveolin-1 expression and extrathyroidal invasion (p < 0.05 in PTC for both antibodies. Additionally, AV09019 antibody correlated caveolin-1 upregulation with pathological T status.

  20. Divergent expression and roles for caveolin-1 in mouse hepatocarcinoma cell lines with varying invasive ability

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    Huimin, Zhou [Department of Biochemistry, Institute of Glycobiology, Dalian Medical University, Dalian 116027 (China); Li, Jia [Department of Biochemistry, Institute of Glycobiology, Dalian Medical University, Dalian 116027 (China); Shujing, Wang [Department of Biochemistry, Institute of Glycobiology, Dalian Medical University, Dalian 116027 (China); Hongmei, Wang [Department of Biochemistry, Institute of Glycobiology, Dalian Medical University, Dalian 116027 (China); Department of Medical Microbiology and Parasitology, School of Medicine, Liaodong College, Dandong 118000 (China); Haiying, Chu [Department of Biochemistry, Institute of Glycobiology, Dalian Medical University, Dalian 116027 (China); Yichuan, Hu [Department of Biochemistry, Institute of Glycobiology, Dalian Medical University, Dalian 116027 (China); Jun, Cao [Department of Biochemistry, Institute of Glycobiology, Dalian Medical University, Dalian 116027 (China); Jianing, Zhang [Department of Biochemistry, Institute of Glycobiology, Dalian Medical University, Dalian 116027 (China)

    2006-06-23

    Caveolin-1 is the major component protein of caveolae and associated with a lot of cellular events such as endocytosis, cholesterol homeostasis, signal transduction, and tumorigenesis. The majority of results suggest that caveolin-1 might not only act as a tumor suppressor gene but also a promoting metastasis gene. In this study, the divergent expression and roles of caveolin-1 were investigated in mouse hepatocarcinoma cell lines Hca-F, Hca-P, and Hepa1-6, which have high, low, and no metastatic potential in the lymph nodes, as compared with normal mouse liver cell line IAR-20. The results showed that expression of caveolin-1 mRNA and protein along with the amount of caveolae number in Hca-F cells was higher than that in Hca-P cells, but was not detectable in Hepa1-6 cells. When caveolin-1 expression in Hca-F cells was down-regulated by RNAi approach, Hca-F cells proliferation rate in vitro declined and the expression of lymphangiogenic factor VEGFA in Hca-F decreased as well. Furthermore, in vivo implantation assay indicated that reduction of caveolin-1 expression in Hca-F prevented the lymphatic metastasis tumor burden of Hca-F cells in 615 mice. These results suggest that caveolin-1 facilities the lymphatic metastasis ability of mouse hepatocarcinoma cells via regulation tumor cell growth and VEGFA expression.

  1. Divergent expression and roles for caveolin-1 in mouse hepatocarcinoma cell lines with varying invasive ability

    International Nuclear Information System (INIS)

    Zhou Huimin; Jia Li; Wang Shujing; Wang Hongmei; Chu Haiying; Hu Yichuan; Cao Jun; Zhang Jianing

    2006-01-01

    Caveolin-1 is the major component protein of caveolae and associated with a lot of cellular events such as endocytosis, cholesterol homeostasis, signal transduction, and tumorigenesis. The majority of results suggest that caveolin-1 might not only act as a tumor suppressor gene but also a promoting metastasis gene. In this study, the divergent expression and roles of caveolin-1 were investigated in mouse hepatocarcinoma cell lines Hca-F, Hca-P, and Hepa1-6, which have high, low, and no metastatic potential in the lymph nodes, as compared with normal mouse liver cell line IAR-20. The results showed that expression of caveolin-1 mRNA and protein along with the amount of caveolae number in Hca-F cells was higher than that in Hca-P cells, but was not detectable in Hepa1-6 cells. When caveolin-1 expression in Hca-F cells was down-regulated by RNAi approach, Hca-F cells proliferation rate in vitro declined and the expression of lymphangiogenic factor VEGFA in Hca-F decreased as well. Furthermore, in vivo implantation assay indicated that reduction of caveolin-1 expression in Hca-F prevented the lymphatic metastasis tumor burden of Hca-F cells in 615 mice. These results suggest that caveolin-1 facilities the lymphatic metastasis ability of mouse hepatocarcinoma cells via regulation tumor cell growth and VEGFA expression

  2. Caveolin-1 sensitizes cisplatin-induced lung cancer cell apoptosis via superoxide anion-dependent mechanism.

    Science.gov (United States)

    Pongjit, Kanittha; Chanvorachote, Pithi

    2011-12-01

    Caveolin-1 (Cav-1) expression frequently found in lung cancer was linked with disease prognosis and progression. This study reveals for the first time that Cav-1 sensitizes cisplatin-induced lung carcinoma cell death by the mechanism involving oxidative stress modulation. We established stable Cav-1 overexpressed (H460/Cav-1) cells and investigated their cisplatin susceptibility in comparison with control-transfected cells and found that Cav-1 expression significantly enhanced cisplatin-mediated cell death. Results indicated that the different response to cisplatin between these cells was resulted from different level of superoxide anion induced by cisplatin. Inhibitory study revealed that superoxide anion inhibitor MnTBAP could inhibit cisplatin-mediated toxicity only in H460/Cav-1 cells while had no effect on H460 cells. Further, superoxide anion detected by DHE probe indicated that H460/Cav-1 cells generated significantly higher superoxide anion level in response to cisplatin than that of control cells. The role of Cav-1 in regulating cisplatin sensitivity was confirmed in shRNA-mediated Cav-1 down-regulated (H460/shCav-1) cells and the cells exhibited decreased cisplatin susceptibility and superoxide generation. In summary, these findings reveal novel aspects regarding role of Cav-1 in modulating oxidative stress induced by cisplatin, possibly providing new insights for cancer biology and cisplatin-based chemotherapy.

  3. Up-regulation of endothelial monocyte chemoattractant protein-1 by coplanar PCB77 is caveolin-1-dependent

    International Nuclear Information System (INIS)

    Majkova, Zuzana; Smart, Eric; Toborek, Michal; Hennig, Bernhard

    2009-01-01

    Atherosclerosis, the primary cause of heart disease and stroke is initiated in the vascular endothelium, and risk factors for its development include environmental exposure to persistent organic pollutants. Caveolae are membrane microdomains involved in regulation of many signaling pathways, and in particular in endothelial cells. We tested the hypothesis that intact caveolae are required for coplanar PCB77-induced up-regulation of monocyte chemoattractant protein-1 (MCP-1), an endothelium-derived chemokine that attracts monocytes into sub-endothelial space in early stages of the atherosclerosis development. Atherosclerosis-prone LDL-R -/- mice (control) or caveolin-1 -/- /LDL-R -/- mice were treated with PCB77. PCB77 induced aortic mRNA expression and plasma protein levels of MCP-1 in control, but not caveolin-1 -/- /LDL-R -/- mice. To study the mechanism of this effect, primary endothelial cells were used. PCB77 increased MCP-1 levels in endothelial cells in a time- and concentration-dependent manner. This effect was abolished by caveolin-1 silencing using siRNA. Also, MCP-1 up-regulation by PCB77 was prevented by inhibiting p38 and c-Jun N-terminal kinase (JNK), but not ERK1/2, suggesting regulatory functions via p38 and JNK MAPK pathways. Finally, pre-treatment of endothelial cells with the aryl hydrocarbon receptor (AhR) inhibitor α-naphthoflavone (α-NF) partially blocked MCP-1 up-regulation. Thus, our data demonstrate that coplanar PCB77 can induce MCP-1 expression by endothelial cells and that this effect is mediated by AhR, as well as p 38 and JNK MAPK pathways. Intact caveolae are required for these processes both in vivo and in vitro. This further supports a key role for caveolae in vascular inflammation induced by persistent organic pollutants.

  4. Caveolin-1 as a Novel Indicator of Wound-Healing Capacity in Aged Human Corneal Epithelium

    OpenAIRE

    Rhim, Ji Heon; Kim, Jae Hoon; Yeo, Eui-Ju; Kim, Jae Chan; Park, Sang Chul

    2010-01-01

    Excess caveolin-1 has been reported to play a role in age-dependent hyporesponsiveness to growth factors in vitro. Therefore, we hypothesized that caveolin-1–dependent hyporesponsiveness to growth factors in aged corneal epithelial cells might be responsible for delayed wound healing in vivo. To test this hypothesis, we evaluated corneal wound-healing time by vital staining using fluorescein after laser epithelial keratomileusis (LASEK). We compared wound-healing times in young, middle-aged a...

  5. Growth suppression of MCF-7 cancer cell-derived xenografts in nude mice by caveolin-1

    International Nuclear Information System (INIS)

    Wu Ping; Wang Xiaohui; Li Fei; Qi Baoju; Zhu Hua; Liu Shuang; Cui Yeqing; Chen Jianwen

    2008-01-01

    Caveolin-1 is an essential structural constituent of caveolae membrane domains that has been implicated in mitogenic signaling and oncogenesis. However, the exact functional role of caveolin-1 still remains controversial. In this report, utilizing MCF-7 human breast adenocarcinoma cells stably transfected with caveolin-1 (MCF-7/cav-1 cells), we demonstrate that caveolin-1 expression dramatically inhibits invasion and migration of these cells. Importantly, in vivo experiments employing xenograft tumor models demonstrated that expression of caveolin-1 results in significant growth inhibition of breast tumors. Moreover, a dramatic delay in tumor progression was observed in MCF-7/cav-1 cells as compared with MCF-7 cells. Histological analysis of tumor sections demonstrated a marked decrease in the percentage of proliferating tumor cells (Ki-67 assay) along with an increase in apoptotic tumor cells (TUNEL assay) in MCF-7/cav-1-treated animals. Our current findings provide for the first time in vivo evidence that caveolin-1 can indeed function as a tumor suppressor in human breast adenocarcinoma derived from MCF-7 cells rather than as a tumor promoter

  6. Caveolin-1 protects B6129 mice against Helicobacter pylori gastritis.

    Directory of Open Access Journals (Sweden)

    Ivana Hitkova

    Full Text Available Caveolin-1 (Cav1 is a scaffold protein and pathogen receptor in the mucosa of the gastrointestinal tract. Chronic infection of gastric epithelial cells by Helicobacter pylori (H. pylori is a major risk factor for human gastric cancer (GC where Cav1 is frequently down-regulated. However, the function of Cav1 in H. pylori infection and pathogenesis of GC remained unknown. We show here that Cav1-deficient mice, infected for 11 months with the CagA-delivery deficient H. pylori strain SS1, developed more severe gastritis and tissue damage, including loss of parietal cells and foveolar hyperplasia, and displayed lower colonisation of the gastric mucosa than wild-type B6129 littermates. Cav1-null mice showed enhanced infiltration of macrophages and B-cells and secretion of chemokines (RANTES but had reduced levels of CD25+ regulatory T-cells. Cav1-deficient human GC cells (AGS, infected with the CagA-delivery proficient H. pylori strain G27, were more sensitive to CagA-related cytoskeletal stress morphologies ("humming bird" compared to AGS cells stably transfected with Cav1 (AGS/Cav1. Infection of AGS/Cav1 cells triggered the recruitment of p120 RhoGTPase-activating protein/deleted in liver cancer-1 (p120RhoGAP/DLC1 to Cav1 and counteracted CagA-induced cytoskeletal rearrangements. In human GC cell lines (MKN45, N87 and mouse stomach tissue, H. pylori down-regulated endogenous expression of Cav1 independently of CagA. Mechanistically, H. pylori activated sterol-responsive element-binding protein-1 (SREBP1 to repress transcription of the human Cav1 gene from sterol-responsive elements (SREs in the proximal Cav1 promoter. These data suggested a protective role of Cav1 against H. pylori-induced inflammation and tissue damage. We propose that H. pylori exploits down-regulation of Cav1 to subvert the host's immune response and to promote signalling of its virulence factors in host cells.

  7. Caveolin-1 expression as a prognostic marker in triple negative breast cancers of Asian women.

    Science.gov (United States)

    Yeong, Joe; Thike, Aye Aye; Ikeda, Murasaki; Lim, Jeffrey Chun Tatt; Lee, Bernett; Nakamura, Seigo; Iqbal, Jabed; Tan, Puay Hoon

    2018-02-01

    Triple-negative breast cancers (TNBCs) are defined by their lack of oestrogen receptor, progesterone receptor and epidermal growth factor receptor 2. Although heterogeneous, the majority are aggressive and treatment options are limited. Caveolin acts as tumour suppressor or promoter depending on the cancer type. In this study, we aimed to determine if the expression levels of the candidate biomarker caveolin-1 on stromal or tumour cells were associated with clinicopathological parameters and disease outcomes in TNBCs from an ethnically diverse cohort of Asian women. Tumour specimens from 699 women with TNBC were subjected to immunohistochemical analysis of the frequency and intensity of caveolin-1 expression in tumour and stromal cells. A subset of 141 tumour samples also underwent Nanostring measurement of CAV1 mRNA. Results were correlated with clinicopathological parameters and disease outcomes. Expression of caveolin-1 in stromal cells was observed in 14.4% of TNBC cases. TNBCs of the basal-like phenotype (85% of samples) were significantly more likely to exhibit stromal cell caveolin-1 expression (p=0.028), as were those with a trabecular growth pattern (p=0.007). Lack of stromal caveolin-1 expression in both TNBCs and those with the basal-like phenotype was significantly associated with worse overall survival (p=0.009 and p=0.026, respectively): accordingly, increasing mRNA levels of CAV1 in TNBC samples predicted better overall survival. Caveolin-1 expression on TNBC tumour cells was not associated with clinical outcome. Stromal, but not tumoural, caveolin-1 expression is significantly associated with survival in Asian women with TNBC. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2018. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

  8. Caveolin-1 interacts with the Gag precursor of murine leukaemia virus and modulates virus production

    Directory of Open Access Journals (Sweden)

    Koester Mario

    2006-09-01

    Full Text Available Abstract Background Retroviral Gag determines virus assembly at the plasma membrane and the formation of virus-like particles in intracellular multivesicular bodies. Thereby, retroviruses exploit by interaction with cellular partners the cellular machineries for vesicular transport in various ways. Results The retroviral Gag precursor protein drives assembly of murine leukaemia viruses (MLV at the plasma membrane (PM and the formation of virus like particles in multivesicular bodies (MVBs. In our study we show that caveolin-1 (Cav-1, a multifunctional membrane-associated protein, co-localizes with Gag in a punctate pattern at the PM of infected NIH 3T3 cells. We provide evidence that Cav-1 interacts with the matrix protein (MA of the Gag precursor. This interaction is mediated by a Cav-1 binding domain (CBD within the N-terminus of MA. Interestingly, the CBD motif identified within MA is highly conserved among most other γ-retroviruses. Furthermore, Cav-1 is incorporated into MLV released from NIH 3T3 cells. Overexpression of a GFP fusion protein containing the putative CBD of the retroviral MA resulted in a considerable decrease in production of infectious retrovirus. Moreover, expression of a dominant-negative Cav-1 mutant affected retroviral titres significantly. Conclusion This study demonstrates that Cav-1 interacts with MLV Gag, co-localizes with Gag at the PM and affects the production of infectious virus. The results strongly suggest a role for Cav-1 in the process of virus assembly.

  9. Caveolin-2 associates with intracellular chlamydial inclusions independently of caveolin-1

    Directory of Open Access Journals (Sweden)

    Norkin Leonard C

    2004-07-01

    Full Text Available Abstract Background Lipid raft domains form in plasma membranes of eukaryotic cells by the tight packing of glycosphingolipids and cholesterol. Caveolae are invaginated structures that form in lipid raft domains when the protein caveolin-1 is expressed. The Chlamydiaceae are obligate intracellular bacterial pathogens that replicate entirely within inclusions that develop from the phagocytic vacuoles in which they enter. We recently found that host cell caveolin-1 is associated with the intracellular vacuoles and inclusions of some chlamydial strains and species, and that entry of those strains depends on intact lipid raft domains. Caveolin-2 is another member of the caveolin family of proteins that is present in caveolae, but of unknown function. Methods We utilized a caveolin-1 negative/caveolin-2 positive FRT cell line and laser confocal immunofluorescence techniques to visualize the colocalization of caveolin-2 with the chlamydial inclusions. Results We show here that in infected HeLa cells, caveolin-2, as well as caveolin-1, colocalizes with inclusions of C. pneumoniae (Cp, C. caviae (GPIC, and C. trachomatis serovars E, F and K. In addition, caveolin-2 also associates with C. trachomatis serovars A, B and C, although caveolin-1 did not colocalize with these organisms. Moreover, caveolin-2 appears to be specifically, or indirectly, associated with the pathogens at the inclusion membranes. Using caveolin-1 deficient FRT cells, we show that although caveolin-2 normally is not transported out of the Golgi in the absence of caveolin-1, it nevertheless colocalizes with chlamydial inclusions in these cells. However, our results also show that caveolin-2 did not colocalize with UV-irradiated Chlamydia in FRT cells, suggesting that in these caveolin-1 negative cells, pathogen viability and very likely pathogen gene expression are necessary for the acquisition of caveolin-2 from the Golgi. Conclusion Caveolin-2 associates with the chlamydial

  10. Domain-Specific Partitioning of Uterine Artery Endothelial Connexin43 and Caveolin-1.

    Science.gov (United States)

    Ampey, Bryan C; Morschauser, Timothy J; Ramadoss, Jayanth; Magness, Ronald R

    2016-10-01

    Uterine vascular adaptations facilitate rises in uterine blood flow during pregnancy, which are associated with gap junction connexin (Cx) proteins and endothelial nitric oxide synthase. In uterine artery endothelial cells (UAECs), ATP activates endothelial nitric oxide synthase in a pregnancy (P)-specific manner that is dependent on Cx43 function. Caveolar subcellular domain partitioning plays key roles in ATP-induced endothelial nitric oxide synthase activation and nitric oxide production. Little is known regarding the partitioning of Cx proteins to caveolar domains or their dynamics with ATP treatment. We observed that Cx43-mediated gap junction function with ATP stimulation is associated with Cx43 repartitioning between the noncaveolar and caveolar domains. Compared with UAECs from nonpregnant (NP) ewes, levels of ATP, PGI2, cAMP, NOx, and cGMP were 2-fold higher (PLucifer yellow dye transfer, a response abrogated by Gap27, but not Gap 26, indicating involvement of Cx43, but not Cx37. Confocal microscopy revealed domain partitioning of Cx43 and caveolin-1. In pregnant UAECs, LC/MS/MS analysis revealed only Cx43 in the caveolar domain. In contrast, Cx37 was located only in the noncaveolar pool. Western analysis revealed that ATP increased Cx43 distribution (1.7-fold; P=0.013) to the caveolar domain, but had no effect on Cx37. These data demonstrate rapid ATP-stimulated repartitioning of Cx43 to the caveolae, where endothelial nitric oxide synthase resides and plays an important role in nitric oxide-mediated increasing uterine blood flow during pregnancy. © 2016 American Heart Association, Inc.

  11. The significance of caveolin-1 expression in parietal epithelial cells of Bowman's capsule.

    Science.gov (United States)

    Ostalska-Nowicka, D; Nowicki, M; Zachwieja, J; Kasper, M; Witt, M

    2007-11-01

    To analyse the expression of caveolin-1 in normal human kidney and during diseases leading to nephrotic syndrome in children and to compare its pattern with those observed in control samples, both human and animal. The study group was composed of 104 children diagnosed with minimal change disease (MCD), focal segmental glomerulosclerosis (FSGS), lupus glomerulonephritis (LGN) and Schönlein-Henoch glomerulopathy (SH). The research protocol employed direct immunohistochemical assay with the use of mono- and polyclonal antibodies against caveolins. Kidney samples of Wistar rats, wild-type mice and caveolin-1-deficient mice were also analysed. In the control human samples, caveolin-1 was most abundant in the muscle layer of blood vessels and parietal epithelial cells (PECs). Its expression in PECs was significantly lower in children diagnosed with FSGS and LGN than in those with MCD, SH or in controls. In the control animal tissues, except for knock-out mice, caveolin-1 was present in distal convoluted tubules, PECs, endothelial cells and muscle. Caveolae are extremely stable elements of PECs and can be excluded from their cell membrane only in response to the dramatic cell reconstruction observed in FSGS and LGN.

  12. High levels of exosomes expressing CD63 and caveolin-1 in plasma of melanoma patients.

    Science.gov (United States)

    Logozzi, Mariantonia; De Milito, Angelo; Lugini, Luana; Borghi, Martina; Calabrò, Luana; Spada, Massimo; Perdicchio, Maurizio; Marino, Maria Lucia; Federici, Cristina; Iessi, Elisabetta; Brambilla, Daria; Venturi, Giulietta; Lozupone, Francesco; Santinami, Mario; Huber, Veronica; Maio, Michele; Rivoltini, Licia; Fais, Stefano

    2009-01-01

    Metastatic melanoma is an untreatable cancer lacking reliable and non-invasive markers of disease progression. Exosomes are small vesicles secreted by normal as well as tumor cells. Human tumor-derived exosomes are involved in malignant progression and we evaluated the presence of exosomes in plasma of melanoma patients as a potential tool for cancer screening and follow-up. We designed an in-house sandwich ELISA (Exotest) to capture and quantify exosomes in plasma based on expression of housekeeping proteins (CD63 and Rab-5b) and a tumor-associated marker (caveolin-1). Western blot and flow cytometry analysis of exosomes were used to confirm the Exotest-based findings. The Exotest allowed sensitive detection and quantification of exosomes purified from human tumor cell culture supernatants and plasma from SCID mice engrafted with human melanoma. Plasma levels of exosomes in melanoma-engrafted SCID mice correlated to tumor size. We evaluated the levels of plasma exosomes expressing CD63 and caveolin-1 in melanoma patients (n = 90) and healthy donors (n = 58). Consistently, plasma exosomes expressing CD63 (504+/-315) or caveolin-1 (619+/-310) were significantly increased in melanoma patients as compared to healthy donors (223+/-125 and 228+/-102, respectively). While the Exotest for CD63+ plasma exosomes had limited sensitivity (43%) the Exotest for detection of caveolin-1+ plasma exosomes showed a higher sensitivity (68%). Moreover, caveolin-1+ plasma exosomes were significantly increased with respect to CD63+ exosomes in the patients group. We describe a new non-invasive assay allowing detection and quantification of human exosomes in plasma of melanoma patients. Our results suggest that the Exotest for detection of plasma exosomes carrying tumor-associated antigens may represent a novel tool for clinical management of cancer patients.

  13. High levels of exosomes expressing CD63 and caveolin-1 in plasma of melanoma patients.

    Directory of Open Access Journals (Sweden)

    Mariantonia Logozzi

    Full Text Available BACKGROUND: Metastatic melanoma is an untreatable cancer lacking reliable and non-invasive markers of disease progression. Exosomes are small vesicles secreted by normal as well as tumor cells. Human tumor-derived exosomes are involved in malignant progression and we evaluated the presence of exosomes in plasma of melanoma patients as a potential tool for cancer screening and follow-up. METHODOLOGY/PRINCIPAL FINDINGS: We designed an in-house sandwich ELISA (Exotest to capture and quantify exosomes in plasma based on expression of housekeeping proteins (CD63 and Rab-5b and a tumor-associated marker (caveolin-1. Western blot and flow cytometry analysis of exosomes were used to confirm the Exotest-based findings. The Exotest allowed sensitive detection and quantification of exosomes purified from human tumor cell culture supernatants and plasma from SCID mice engrafted with human melanoma. Plasma levels of exosomes in melanoma-engrafted SCID mice correlated to tumor size. We evaluated the levels of plasma exosomes expressing CD63 and caveolin-1 in melanoma patients (n = 90 and healthy donors (n = 58. Consistently, plasma exosomes expressing CD63 (504+/-315 or caveolin-1 (619+/-310 were significantly increased in melanoma patients as compared to healthy donors (223+/-125 and 228+/-102, respectively. While the Exotest for CD63+ plasma exosomes had limited sensitivity (43% the Exotest for detection of caveolin-1+ plasma exosomes showed a higher sensitivity (68%. Moreover, caveolin-1+ plasma exosomes were significantly increased with respect to CD63+ exosomes in the patients group. CONCLUSIONS/SIGNIFICANCE: We describe a new non-invasive assay allowing detection and quantification of human exosomes in plasma of melanoma patients. Our results suggest that the Exotest for detection of plasma exosomes carrying tumor-associated antigens may represent a novel tool for clinical management of cancer patients.

  14. Oxidative stress induces caveolin 1 degradation and impairs caveolae functions in skeletal muscle cells.

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    Alexis Mougeolle

    Full Text Available Increased level of oxidative stress, a major actor of cellular aging, impairs the regenerative capacity of skeletal muscle and leads to the reduction in the number and size of muscle fibers causing sarcopenia. Caveolin 1 is the major component of caveolae, small membrane invaginations involved in signaling and endocytic trafficking. Their role has recently expanded to mechanosensing and to the regulation of oxidative stress-induced pathways. Here, we increased the amount of reactive oxidative species in myoblasts by addition of hydrogen peroxide (H2O2 at non-toxic concentrations. The expression level of caveolin 1 was significantly decreased as early as 10 min after 500 μM H2O2 treatment. This reduction was not observed in the presence of a proteasome inhibitor, suggesting that caveolin 1 was rapidly degraded by the proteasome. In spite of caveolin 1 decrease, caveolae were still able to assemble at the plasma membrane. Their functions however were significantly perturbed by oxidative stress. Endocytosis of a ceramide analog monitored by flow cytometry was significantly diminished after H2O2 treatment, indicating that oxidative stress impaired its selective internalization via caveolae. The contribution of caveolae to the plasma membrane reservoir has been monitored after osmotic cell swelling. H2O2 treatment increased membrane fragility revealing that treated cells were more sensitive to an acute mechanical stress. Altogether, our results indicate that H2O2 decreased caveolin 1 expression and impaired caveolae functions. These data give new insights on age-related deficiencies in skeletal muscle.

  15. The role of Caveolin-1 in Lipid Droplets and their Biogenesis

    DEFF Research Database (Denmark)

    Pezeshkian, Weria; Chevrot, Guillaume; Khandelia, Himanshu

    2018-01-01

    the effects of a curvature-inducing protein, caveolin-1, on the formation and structure of a spontaneously aggregated triolein (TO) lipid lens in a flat lipid bilayer using Molecular Dynamics (MD) simulations. A truncated form of Caveolin-1 (Cav1) localises on the interface between the spontaneously formed...... TO aggregate and the bulk bilayer, and thins the bilayer at the edge of the aggregate, which may contribute to lowering the energy barrier for pinching off the aggregate from the host bilayer. Simulations of fully mature LDs do not conclusively establish the optimal localisation of Cav1 in LDs, but when Cav1...... is in the LD core, the distribution of both neutral lipids in the LD core, and of phospholipids on the engulfing monolayer are altered significantly. Our simulations provide an unprecedented molecular description of the distribution and dynamics of various lipid species in both mature LDs and in the nascent LD...

  16. Cholesterol and phytosterols differentially regulate the expression of caveolin 1 and a downstream prostate cell growth-suppressor gene

    Science.gov (United States)

    Ifere, Godwin O.; Equan, Anita; Gordon, Kereen; Nagappan, Peri; Igietseme, Joseph U.; Ananaba, Godwin A.

    2010-01-01

    Background The purpose of our study was to show the distinction between the apoptotic and anti-proliferative signaling of phytosterols and cholesterol enrichment in prostate cancer cell lines, mediated by the differential transcription of caveolin-1, and N-myc downstream regulated gene1 (NDRG1), a pro-apoptotic androgen-regulated tumor suppressor. Methods PC-3 and DU145 cells were treated with sterols (cholesterol and phytosterols) for 72 h, followed by trypan blue dye exclusion measurement of necrosis and cell growth measured with a Coulter counter. Sterol induction of cell growth-suppressor gene expression was evaluated by mRNA transcription using RT-PCR, while cell cycle analysis was performed by FACS analysis. Altered expression of Ndrg1 protein was confirmed by Western blot analysis. Apoptosis was evaluated by real time RT-PCR amplification of P53, Bcl-2 gene and its related pro- and anti-apoptotic family members. Results Physiological doses (16 µM) of cholesterol and phytosterols were not cytotoxic in these cells. Cholesterol enrichment promoted cell growth (Pphytosterols significantly induced growth-suppression (Pphytosterols decreased mitotic subpopulations. We demonstrated for the first time that cholesterols concertedly attenuated the expression of caveolin-1(cav-1) and NDRG1 genes in both prostate cancer cell lines. Phytosterols had the opposite effect by inducing overexpression of cav-1, a known mediator of androgen-dependent signals that presumably control cell growth or apoptosis. Conclusions Cholesterol and phytosterol treatment differentially regulated the growth of prostate cancer cells and the expression of p53 and cav-1, a gene that regulates androgen-regulated signals. These sterols also differentially regulated cell cycle arrest, downstream pro-apoptotic androgen-regulated tumor-suppressor, NDRG1 suggesting that cav-1 may mediate pro-apoptotic NDRG1 signals. Elucidation of the mechanism for sterol modulation of growth and apoptosis signaling

  17. Prognostic significance of epithelial/stromal caveolin-1 expression in prostatic hyperplasia, high grade prostatic intraepithelial hyperplasia and prostatic carcinoma and its correlation with microvessel density.

    Science.gov (United States)

    Mohammed, Dareen A; Helal, Duaa S

    2017-03-01

    Caveolin-1 may play a role in cancer development and progression. The aim was to record the expression and localization of caveolin-1 in benign prostatic hyperplasia (BPH), high grade prostatic intraepithelial neoplasia (HGPIN) and prostatic carcinoma (PCa). Microvessel density was evaluated with CD34 immunostain. Correlations with known prognostic factors of PCa were recorded. Immunohistochemical expression of caveolin-1 and the MVD was evaluated in 65 cases; BPH (25), HGPIN (20) and PCa (20). Stromal caveolin-1expression was significantly higher in BPH than HGPIN and PCca. There was significant inverse relation between stromal caveolin-1 expression and extension to lymph node and seminal vesicle in carcinoma cases. Epithelial caveolin-1 was significantly higher in carcinomas than in BPH and HGPIN. Epithelial expression in carcinoma was significantly associated with preoperative PSA, Gleason score and lymph node extension. MVD was significantly higher in PCa than in BPH and HGPIN. There were significant relations between MVD and preoperative PSA, Gleason score, lymph node and seminal vesicle extension. Stromal caveolin-1 was associated with low MVD while epithelial caveolin-1 with high MVD. Caveolin-1 plays an important role in prostatic carcinogenesis and metastasis. Stromal expression of caveolin-1 in PCa is lowered in relation to BPH and HGPIN. In PCa; stromal caveolin-1 was associated with good prognostic parameters. Epithelial caveolin-1 is significantly increased in PCa than BPH and HGPIN. It is associated with clinically aggressive disease. Caveolin-1 may play a role in angiogenesis. Copyright © 2017 National Cancer Institute, Cairo University. Production and hosting by Elsevier B.V. All rights reserved.

  18. The Importance of Caveolin-1 as Key-Regulator of Three-Dimensional Growth in Thyroid Cancer Cells Cultured under Real and Simulated Microgravity Conditions

    Directory of Open Access Journals (Sweden)

    Stefan Riwaldt

    2015-11-01

    Full Text Available We recently demonstrated that the CAV1 gene was down-regulated, when poorly differentiated thyroid FTC-133 cancer cells formed spheroids under simulated microgravity conditions. Here, we present evidence that the caveolin-1 protein is involved in the inhibition of spheroid formation, when confluent monolayers are exposed to microgravity. The evidence is based on proteins detected in cells and their supernatants of the recent spaceflight experiment: “NanoRacks-CellBox-Thyroid Cancer”. The culture supernatant had been collected in a special container adjacent to the flight hardware incubation chamber and stored at low temperature until it was analyzed by Multi-Analyte Profiling (MAP technology, while the cells remaining in the incubation chamber were fixed by RNAlater and examined by mass spectrometry. The soluble proteins identified by MAP were investigated in regard to their mutual interactions and their influence on proteins, which were associated with the cells secreting the soluble proteins and had been identified in a preceding study. A Pathway Studio v.11 analysis of the soluble and cell-associated proteins together with protein kinase C alpha (PRKCA suggests that caveolin-1 is involved, when plasminogen enriched in the extracellular space is not activated and the vascular cellular adhesion molecule (VCAM-1 mediated cell–cell adhesion is simultaneously strengthened and activated PRKCA is recruited in caveolae, while the thyroid cancer cells do not form spheroids.

  19. Effect of TNF-Alpha on Caveolin-1 Expression and Insulin Signaling During Adipocyte Differentiation and in Mature Adipocytes

    Directory of Open Access Journals (Sweden)

    Sara Palacios-Ortega

    2015-07-01

    Full Text Available Background/Aims: Tumor necrosis factor-α (TNF-α-mediated chronic low-grade inflammation of adipose tissue is associated with obesity and insulin resistance. Caveolin-1 (Cav-1 is the central component of adipocyte caveolae and has an essential role in the regulation of insulin signaling. The effects of TNF-α on Cav-1 expression and insulin signaling during adipocyte differentiation and in mature adipocytes were studied. Methods: 3T3-L1 cells were differentiated (21 days in the presence TNF-α (10 ng/mL and mature adipocytes were also treated with TNF-α for 48 hours. Cav-1 and insulin receptor (IR gene methylation were determined as well as Cav-1, IR, PKB/AKT-2 and Glut-4 expression and activation by real time RT-PCR and western blot. Baseline and insulin-induced glucose uptake was measured by the 2-[C14]-deoxyglucose uptake assay. Results: TNF-α slowed down the differentiation program, hindering the expression of some insulin signaling intermediates without fully eliminating insulin-mediated glucose uptake. In mature adipocytes, TNF-α did not compromise lipid-storage capacity, but downregulated the expression of the insulin signaling intermediates, totally blocking insulin-mediated glucose uptake. Insulin sensitivity correlated with the level of activated phospho-Cav-1 in both situations, strongly suggesting the direct contribution of Cav-1 to the maintenance of this physiological response. Conclusion: Cav-1 activation by phosphorylation seems to be essential for the maintenance of an active and insulin-sensitive glucose uptake.

  20. Caveolin-1 single nucleotide polymorphism in antineutrophil cytoplasmic antibody associated vasculitis.

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    Sourabh Chand

    Full Text Available Immunosuppression is cornerstone treatment of antineutrophil cytoplasmic antibody associated vasculitis (AAV but is later complicated by infection, cancer, cardiovascular and chronic kidney disease. Caveolin-1 is an essential structural protein for small cell membrane invaginations known as caveolae. Its functional role has been associated with these complications. For the first time, caveolin-1 (CAV1 gene variation is studied in AAV.CAV1 single nucleotide polymorphism rs4730751 was analysed in genomic DNA from 187 white patients with AAV from Birmingham, United Kingdom. The primary outcome measure was the composite endpoint of time to all-cause mortality or renal replacement therapy. Secondary endpoints included time to all-cause mortality, death from sepsis or vascular disease, cancer and renal replacement therapy. Validation of results was sought from 589 white AAV patients, from two European cohorts.The primary outcome occurred in 41.7% of Birmingham patients. In a multivariate model, non-CC genotype variation at the studied single nucleotide polymorphism was associated with increased risk from: the primary outcome measure [HR 1.86; 95% CI: 1.14-3.04; p=0.013], all-cause mortality [HR:1.83; 95% CI: 1.02-3.27; p=0.042], death from infection [HR:3.71; 95% CI: 1.28-10.77; p=0.016], death from vascular disease [HR:3.13; 95% CI: 1.07-9.10; p=0.037], and cancer [HR:5.55; 95% CI: 1.59-19.31; p=0.007]. In the validation cohort, the primary outcome rate was far lower (10.4%; no association between genotype and the studied endpoints was evident.The presence of a CC genotype in Birmingham is associated with protection from adverse outcomes of immunosuppression treated AAV. Lack of replication in the European cohort may have resulted from low clinical event rates. These findings are worthy of further study in larger cohorts.

  1. ACTH-induced caveolin-1 tyrosine phosphorylation is related to podosome assembly in Y1 adrenal cells

    International Nuclear Information System (INIS)

    Colonna, Cecilia; Podesta, Ernesto J.

    2005-01-01

    Y1 adrenocortical cells respond to ACTH with a characteristic rounding-up that facilitates cAMP signaling, critical for transport of cholesterol to the mitochondria and increase in steroid secretion. We here demonstrate that caveolin-1 participates in coupling activation of protein kinase A (PKA) to the control of cell shape. ACTH/8-Br-cAMP induced reorganization of caveolin-1-positive structures in correlation with the cellular rounding-up. Concomitant with this change, there was an increase in the phosphorylation of caveolin-1 (Tyr-14) localized at focal adhesions (FA) with reorganization of FA to rounded, ringlike structures. Colocalization with phalloidin showed that phosphocaveolin is present at the edge of actin filaments and that after ACTH stimulation F-actin dots at the cell periphery become surrounded by phosphocaveolin-1. These observations along with electron microscopy studies revealed these structures as podosomes. Podosome assembly was dependent on both PKA and tyrosine kinase activities because their formation was impaired after treatment with specific inhibitors [myristoylated PKI (mPKI) or PP2, respectively] previous to ACTH/8-Br-cAMP stimulation. These results show for the first time that ACTH induces caveolin-1 phosphorylation and podosome assembly in Y1 cells and support the view that the morphological and functional responses to PKA activation in steroidogenic cells are related to cytoskeleton dynamics

  2. Cell adhesion-mediated radioresistance (CAM-RR). Extracellular matrix-dependent improvement of cell survival in human tumor and normal cells in vitro

    International Nuclear Information System (INIS)

    Cordes, N.; Meineke, V.

    2003-01-01

    Background: Cell-extracellular matrix (ECM) contact is thought to have great impact on cellular mechanisms resulting in increased cell survival upon exposure to ionizing radiation. Several human tumor cell lines and normal human fibroblastic cell strains of different origin, all of them expressing the wide-spread and important integrin subunit β1, were irradiated, and clonogenic cell survival, β1-integrin cell surface expression, and adhesive functionality were investigated. Material and Methods: Human tumor cell lines A172 (glioblastoma), PATU8902 (pancreas carcinoma), SKMES1 (lung carcinoma), A549 (lung carcinoma), and IPC298 (melanoma) as well as normal human skin (HSF1) and lung fibroblasts (CCD32) and human keratinocytes (HaCaT) were irradiated with 0-8 Gy. Besides colony formation assays, β1-integrin cell surface expression by flow cytometry and adhesive functionality by adhesion assays were analyzed. Results: All cell lines showed improved clonogenic survival after irradiation in the presence of fibronectin as compared to plastic. Irradiated cells exhibited a significant, dose-dependent increase in β1-integrin cell surface expression following irradiation. As a parameter of the adhesive functionality of the β1-integrin, a radiation-dependent elevation of cell adhesion to fibronectin in comparison with adhesion to plastic was demonstrated. Conclusion: The in vitro cellular radiosensitivity is highly influenced by fibronectin according to the phenomenon of cell adhesion-mediated radioresistance. Additionally, our emerging data question the results of former and current in vitro cytotoxicity studies performed in the absence of an ECM. These findings might also be important for the understanding of malignant transformation, anchorage-independent cell growth, optimization of radiotherapeutic regimes and the prevention of normal tissue side effects on the basis of experimental radiobiological data. (orig.)

  3. Extremely radioresistant microbe Deinococcus radiodurans does not survive tellurite-mediated oxidative stress: revelation of molecular basis

    International Nuclear Information System (INIS)

    Apte, Shree Kumar; Narasimha, Anaganti; Basu, Bhakti

    2014-01-01

    Deinococcus radiodurans exhibits extraordinary resistance to gamma radiation as well as oxidative stress. Comparison of tellurite stress with gamma irradiation, both of which impart severe oxidative stress, revealed that tellurite induced less ROS and caused less oxidative damage to proteins, but was much more lethal to D. radiodurans than gamma irradiation. The proteomic changes induced by tellurite exposure were mapped by two dimensional protein electrophoresis followed by mass spectrometry. Seventy proteins belonging to major functional categories of oxidative stress alleviation, protein translation/folding and metabolism were identified. Tellurite responsive proteome dynamics displayed (i) up-regulation of proteins involved in tellurite stress resistance and oxidative stress alleviation, dehydrogenases involved in generation of reducing potential, and chaperones (such DnaK), and (ii) down regulation of key glycolysis and TCA cycle enzymes, proteins involved in protein translation/folding and energy production. Tellurite stress also resulted in nearly 50% loss in the cellular reducing potential within 1h of exposure while gamma irradiation had no such effect. The findings provide a better insight into the mechanism of tellurite toxicity, beyond metal mediated oxidative stress, in this extremophile. (author)

  4. Altered Cross-Linking of HSP27 by Zerumbone as a Novel Strategy for Overcoming HSP27-Mediated Radioresistance

    International Nuclear Information System (INIS)

    Choi, Seo-Hyun; Lee, Yoon-Jin; Seo, Woo Duck; Lee, Hae-June; Nam, Joo-Won; Lee, Yoo Jin; Kim, Joon; Seo, Eun-Kyoung; Lee, Yun-Sil

    2011-01-01

    Purpose: HSP27 or HSP25 negatively regulates apoptosis pathways after radiation or chemotherapeutic agents. Abrogation of HSP27 function may be a candidate target for overcoming radio- and chemoresistance. Methods and Materials: Zerumbone (ZER), a cytotoxic component isolated from Zingiber zerumbet smith. Clonogenic survival assay and flow cytometry after Annexin V staining were performed to determine in vitro sensitization effects of ZER with ionizing radiation. A nude mouse xenografting system was also applied to detect in vivo radiosensitizing effects of ZER. Results: ZER produced cross-linking of HSP27, which was dependent on inhibition of the monomeric form of HSP27. ZER was directly inserted between the disulfide bond in the HSP27 dimer and modified normal HSP27 dimerization. Pretreatment with ZER before radiation inhibited the binding affinity between HSP27 and apoptotic molecules, such as cytochrome c and PKCδ, and induced sensitization in vitro and in an in vivo xenografted nude mouse system. Structural analogs lacking only the carbonyl group in ZER, such as α-humulene (HUM) and 8-hydroxy-humulen (8-OH-HUM), did not affect normal cross-linking of HSP27 and did not induce radiosensitization. Conclusions: We suggest that altered cross-linking of HSP27 by ZER is a good strategy for abolishing HSP27-mediated resistance.

  5. Caveolin-1 contributes to realgar nanoparticle therapy in human chronic myelogenous leukemia K562 cells

    Directory of Open Access Journals (Sweden)

    Shi D

    2016-11-01

    Full Text Available Dan Shi,1,* Yan Liu,1,* Ronggang Xi,1 Wei Zou,2 Lijun Wu,3 Zhiran Zhang,1 Zhongyang Liu,1 Chao Qu,1 Baoli Xu,1 Xiaobo Wang1 1Department of Pharmacy, The 210th Hospital of People’s Liberation Army, 2College of Life Science, Liaoning Normal University, Dalian, Liaoning, 3Department of Pharmaceutics, College of Pharmacy, Harbin Medical University, Harbin, Heilongjiang, People’s Republic of China *These authors contributed equally to this work Abstract: Chronic myelogenous leukemia (CML is characterized by the t(9;22 (q34;q11-associated Bcr-Abl fusion gene, which is an essential element of clinical diagnosis. As a traditional Chinese medicine, realgar has been widely used for the treatment of various diseases for >1,500 years. Inspired by nano-drug, realgar nanoparticles (NPs have been prepared with an average particle size of <100 nm in a previous work. Compared with coarse realgar, the realgar NPs have higher bioavailability. As a principal constituent protein of caveolae, caveolin-1 (Cav-1 participates in regulating various cellular physiological and pathological processes including tumorigenesis and tumor development. In previous studies, it was found that realgar NPs can inhibit several types of tumor cell proliferation. However, the therapeutic effect of realgar NPs on CML has not been fully elucidated. In the present paper, it was demonstrated that realgar NPs can inhibit the proliferation of K562 cells and degrade Bcr-Abl fusion protein effectively. Both apoptosis and autophagy were activated in a dose-dependent manner in realgar NPs treated cells, and the induction of autophagy was associated with class I phosphoinositide 3-kinase/protein kinase B/mammalian target of rapamycin pathway. Morphological analysis indicated that realgar NPs induced differentiation effectively in CML cells. Furthermore, it was identified that Cav-1 might play a crucial role in realgar NP therapy. In order to study the effects of Cav-1 on K562 cells during

  6. Stromal and Epithelial Caveolin-1 Both Confer a Protective Effect Against Mammary Hyperplasia and Tumorigenesis

    Science.gov (United States)

    Williams, Terence M.; Sotgia, Federica; Lee, Hyangkyu; Hassan, Ghada; Di Vizio, Dolores; Bonuccelli, Gloria; Capozza, Franco; Mercier, Isabelle; Rui, Hallgeir; Pestell, Richard G.; Lisanti, Michael P.

    2006-01-01

    Here, we investigate the role of caveolin-1 (Cav-1) in breast cancer onset and progression, with a focus on epithelial-stromal interactions, ie, the tumor microenvironment. Cav-1 is highly expressed in adipocytes and is abundant in mammary fat pads (stroma), but it remains unknown whether loss of Cav-1 within mammary stromal cells affects the differentiated state of mammary epithelia via paracrine signaling. To address this issue, we characterized the development of the mammary ductal system in Cav-1−/− mice and performed a series of mammary transplant studies, using both wild-type and Cav-1−/− mammary fat pads. Cav-1−/− mammary epithelia were hyperproliferative in vivo, with dramatic increases in terminal end bud area and mammary ductal thickness as well as increases in bromodeoxyuridine incorporation, extracellular signal-regulated kinase-1/2 hyperactivation, and up-regulation of STAT5a and cyclin D1. Consistent with these findings, loss of Cav-1 dramatically exacerbated mammary lobulo-alveolar hyperplasia in cyclin D1 Tg mice, whereas overexpression of Cav-1 caused reversion of this phenotype. Most importantly, Cav-1−/− mammary stromal cells (fat pads) promoted the growth of both normal mammary ductal epithelia and mammary tumor cells. Thus, Cav-1 expression in both epithelial and stromal cells provides a protective effect against mammary hyperplasia as well as mammary tumorigenesis. PMID:17071600

  7. Lower Serum Caveolin-1 Is Associated with Cerebral Microbleeds in Patients with Acute Ischemic Stroke

    Directory of Open Access Journals (Sweden)

    Jun Zhang

    2016-01-01

    Full Text Available Caveolin-1 (Cav-1 plays pivotal roles in the endothelial damage following stroke. The present study aimed to investigate whether serum Cav-1 level is associated with the presence of cerebral small vessel disease (cSVD in patients with acute ischemic stroke. To this end, 156 patients were consecutively enrolled. Cranial magnetic resonance imaging was analyzed to determine the surrogates of cSVD, including cerebral microbleeds (CMBs, silent lacunar infarcts (SLIs, and white matter hyperintensities (WMHs. After adjusting for potential confounders, patients with low Cav-1 level had a higher risk of CMBs than patients with high Cav-1 level (OR: 4.05, 95% CI: 1.77–9.30. However, there was no relationship between Cav-1 and the presence of SLIs or WMHs. When CMBs were stratified by location and number, a similar association was found in patients with deep or infratentorial CMBs (OR: 4.04, 95% CI: 1.59–10.25 and with multiple CMBs (OR: 3.18, 95% CI: 1.16–8.72. These results suggest lower serum Cav-1 levels may be associated with CMBs, especially those that are multiple and located in deep brain or infratentorial structures, in patients with acute ischemic stroke. Cav-1 may be involved in the pathophysiology of CMBs, and may act as a potential target for treating cSVD.

  8. Caveolin-1 expression level in cancer associated fibroblasts predicts outcome in gastric cancer.

    Directory of Open Access Journals (Sweden)

    Xianda Zhao

    Full Text Available AIMS: Altered expression of epithelial or stromal caveolin-1 (Cav-1 is observed in various types of human cancers. However, the clinical significance of Cav-1 expression in gastric cancer (GC remains largely unknown. The present study aims to explore the clinicopathological significance and prognostic value of both tumor cells and cancer associated fibroblasts (CAFs Cav-1 in GC. METHODS AND RESULTS: Quantum dots immunofluorescence histochemistry was performed to examine the expression of Cav-1 in 20 cases of gastritis without intestinal metaplasia (IM, 20 cases of gastritis with IM and 286 cases of GC. Positive rates of epithelial Cav-1 in gastritis without IM, gastritis with IM and GC showed a decreasing trend (P = 0.012. Low expression of Cav-1 in CAFs but not in tumor cells was an independent predictor of poor prognosis in GC patients (P = 0.034 and 0.005 respectively in disease free survival and overall survival. Cav-1 level in tumor cells and CAFs showed no significant correlation with classic clinicopathological features. CONCLUSIONS: Loss of epithelial Cav-1 may promote malignant progression and low CAFs Cav-1 level herald worse outcome of GC patient, suggesting CAFs Cav-1 may be a candidate therapeutic target and a useful prognostic marker of GC.

  9. Paired hormone response elements predict caveolin-1 as a glucocorticoid target gene.

    Directory of Open Access Journals (Sweden)

    Marinus F van Batenburg

    2010-01-01

    Full Text Available Glucocorticoids act in part via glucocorticoid receptor binding to hormone response elements (HREs, but their direct target genes in vivo are still largely unknown. We developed the criterion that genomic occurrence of paired HREs at an inter-HRE distance less than 200 bp predicts hormone responsiveness, based on synergy of multiple HREs, and HRE information from known target genes. This criterion predicts a substantial number of novel responsive genes, when applied to genomic regions 10 kb upstream of genes. Multiple-tissue in situ hybridization showed that mRNA expression of 6 out of 10 selected genes was induced in a tissue-specific manner in mice treated with a single dose of corticosterone, with the spleen being the most responsive organ. Caveolin-1 was strongly responsive in several organs, and the HRE pair in its upstream region showed increased occupancy by glucocorticoid receptor in response to corticosterone. Our approach allowed for discovery of novel tissue specific glucocorticoid target genes, which may exemplify responses underlying the permissive actions of glucocorticoids.

  10. Reciprocal activating crosstalk between c-Met and caveolin 1 promotes invasive phenotype in hepatocellular carcinoma.

    Science.gov (United States)

    Korhan, Peyda; Erdal, Esra; Kandemiş, Emine; Cokaklı, Murat; Nart, Deniz; Yılmaz, Funda; Can, Alp; Atabey, Neşe

    2014-01-01

    c-Met, the receptor for Hepatocyte Growth Factor (HGF), overexpressed and deregulated in Hepatocellular Carcinoma (HCC). Caveolin 1 (CAV1), a plasma membrane protein that modulates signal transduction molecules, is also overexpressed in HCC. The aim of this study was to investigate biological and clinical significance of co-expression and activation of c-Met and CAV1 in HCC. We showed that c-Met and CAV1 were co-localized in HCC cells and HGF treatment increased this association. HGF-triggered c-Met activation caused a concurrent rise in both phosphorylation and expression of CAV1. Ectopic expression of CAV1 accelerated c-Met signaling, resulted in enhanced migration, invasion, and branching-morphogenesis. Silencing of CAV1 downregulated c-Met signaling, and decreased migratory/invasive capability of cells and attenuated branching morphogenesis. In addition, activation and co-localization of c-Met and CAV1 were elevated during hepatocarcinogenesis. In conclusion reciprocal activating crosstalk between c-Met and CAV1 promoted oncogenic signaling of c-Met contributed to the initiation and progression of HCC.

  11. Reciprocal activating crosstalk between c-Met and caveolin 1 promotes invasive phenotype in hepatocellular carcinoma.

    Directory of Open Access Journals (Sweden)

    Peyda Korhan

    Full Text Available c-Met, the receptor for Hepatocyte Growth Factor (HGF, overexpressed and deregulated in Hepatocellular Carcinoma (HCC. Caveolin 1 (CAV1, a plasma membrane protein that modulates signal transduction molecules, is also overexpressed in HCC. The aim of this study was to investigate biological and clinical significance of co-expression and activation of c-Met and CAV1 in HCC. We showed that c-Met and CAV1 were co-localized in HCC cells and HGF treatment increased this association. HGF-triggered c-Met activation caused a concurrent rise in both phosphorylation and expression of CAV1. Ectopic expression of CAV1 accelerated c-Met signaling, resulted in enhanced migration, invasion, and branching-morphogenesis. Silencing of CAV1 downregulated c-Met signaling, and decreased migratory/invasive capability of cells and attenuated branching morphogenesis. In addition, activation and co-localization of c-Met and CAV1 were elevated during hepatocarcinogenesis. In conclusion reciprocal activating crosstalk between c-Met and CAV1 promoted oncogenic signaling of c-Met contributed to the initiation and progression of HCC.

  12. Caveolin-1 expression in oral lichen planus, dysplastic lesions and squamous cell carcinoma.

    Science.gov (United States)

    Jaafari-Ashkavandi, Zohreh; Aslani, Ehsan

    2017-07-01

    Caveolin-1(Cav-1), the main part of caveolae structure, is supposed to play a role in pathogenesis of many human tumors. Since oral lichen planus (OLP) is considered as a potential premalignant disease, this study evaluated Cav-1 expression in OLP in comparison with benign hyperkeratosis, dysplastic epithelium and oral squamous cell carcinoma (OSCC), to investigate its possible role in pathogenesis and malignant transformation of OLP. In this cross-sectional retrospective study, immunohistochemical expression of Cav-1 in the epithelial component and stroma was evaluated in 81 samples, including 12 cases of hyperkeratosis, 24 OLP, 22 epithelial dysplasia, and 23 OSCC samples. Correlations between Cav-1 expression and clinicopathological variables were evaluated statistically. Positive Cav-1 staining was found in 58% of OLP, 91% of hyperkeratosis, 100% of epithelial dysplasia, and 95% of OSCC samples. OSCC showed the highest Cav-1 expression and OLP had the lowest (P=0.001). The intensity of staining was significantly increased in stepwise manner from OLP to OSCC (P=0.001). Expression of Cav-1 was related to the grade of samples in OSCC and dysplastic samples (P=0.04). Based on the findings, it was concluded that Cav-1 may play a role in the pathogenesis of OLP and carcinogenesis of SCC, but its role in malignant transformation of OLP is not confirmed. Further studies are needed to evaluate its potential therapeutic function in OLP and SCC. Copyright © 2017 Elsevier GmbH. All rights reserved.

  13. Dexamethasone intravitreal implant downregulates PDGFR-α and upregulates caveolin-1 in experimental branch retinal vein occlusion

    DEFF Research Database (Denmark)

    Cehofski, Lasse Jørgensen; Kruse, Anders; Magnusdottir, Sigriður Olga

    2018-01-01

    while the left control eye was given an identical injection without an implant. Fifteen days after BRVO and DEX implant intervention the retinas were excised and analyzed with tandem mass tag based mass spectrometry. A total of 26 significantly changed proteins were identified. Dexamethasone...... following an intervention with a dexamethasone (DEX) implant this study combined an experimental model of BRVO with proteomic techniques. In six Danish Landrace pigs experimental BRVO was induced in both eyes using argon laser. After inducing BRVO a DEX implant was injected in the right eye of each animal......-α and caveolin-1 were confirmed with immunohistochemistry. DEX implant intervention may inhibit PDGF signaling by decreasing the retinal level of PDGFR-α while an increased content of caveolin-1 may help maintain the integrity of the blood-retinal barrier....

  14. Radioresistance and hypoxic cells

    International Nuclear Information System (INIS)

    Ando, Koichi

    1989-01-01

    Current progress to explore further understanding of tumor hypoxia was reviewed. At subcellular level, hypoxia induces specific proteins, inhibits DNA synthesis as well as initiation of DNA replicon. Radioresistant characteristics of hypoxic cells is questioned in condition where irradiated cells were kept hypoxia during colony formation. Chronically hypoxic cells recovered from the inner layer of V79 multicellular spheroids are more sensitive to radiation than those from the oxic, outer layer. A novel sandwich culture method, which enables to reoxygenate chronic hypoxia, implies that chronically hypoxic cells are less sensitive to radiation after reoxygenation than oxic cells. For in vivo tumor, two types of tumor hypoxia are reported: diffusion-limited, chronic hypoxia and perfusion-limited, acute hypoxia. Evidence supporting the existence of perfusion-limited hypoxia is provided by an elegant method using vital staining and cell sorter. Data of our own laboratory also implies 2 types of tumor hypoxia; fractional hypoxia and incomplete hypoxia. Fractional hypoxia corresponds to a radioresistant tail on a biphasic tumor cell survival curves while tumors with incomplete hypoxia demonstrate only single component with radioresistant characteristics, instead. (author)

  15. Radioresistant canine hematopoietic cells

    International Nuclear Information System (INIS)

    Kawakami, T.G.; Shimizu, J.; Rosenblatt, L.S.; Goldman, M.

    1987-01-01

    Survival of dogs that are continuously exposed to a moderate dose-rate of gamma radiation (10 cGy/day) is dependent on the age of the dog at the time of exposure. Most dogs exposed postpartum to gamma radiation suffered from suppressed hematopoiesis and died of aplasia. On the other hand, none of the in utero-exposed dogs suffered from suppressed hematopoiesis and most became long-term survivors, tolerating 10-fold greater total dose, but dying of myeloproliferative disease (MPD). Using acute gamma irradiation of hematopoietic cells and colony forming unit cell assay (CFU), they observed that a canine hematopoietic cell line established from a myeloid leukemic dog that was a long-term survivor of continuous irradiation was approximately 4-fold more radioresistant than a hematopoietic cell line established from a dog with nonradiation-induced myeloid leukemia or hematopoietic cells from normal canine bone marrow. In utero dogs that are long-term survivors of continuous irradiation have radioresistant hematopoietic cells, and radioresistance that is a constitutive property of the cells

  16. Radioresistant microorganisms and food irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Ito, H [Japan Atomic Energy Research Inst., Takasaki, Gunma. Takasaki Radiation Chemistry Research Establishment

    1976-01-01

    This paper deals with Micrococcus radiodurans, Arthrobacter radiotolerance, etc., which were isolated and discovered as radioresistant microorganisms. As for the explanation of the mechanism of radioresistance of these microorganisms, the consideration that these organisms have marked repair power of the damaged DNA and have many opportunity to repair the damaged DNA because of their long fission term were cited. The relationship between the radioresistance of microorganisms and food irradiation was also mentioned.

  17. Differential expression of caveolin-1 in human myometrial and uterine leiomyoma smooth muscle.

    Science.gov (United States)

    Zhou, Yu; Ren, Yuanyuan; Cui, Lihua; Li, Zongjin; Zhu, Yingjun; Lin, Wanjun; Wang, Yuebing

    2014-11-01

    Uterine leiomyomas, the most common neoplasms of the female genital tract, are benign tumors of the uterus arising from the smooth muscle cells (SMCs) of the myometrium with an involvement of estrogen. Caveolin-1 (Cav-1), a major protein component in caveolae membrane lipid rafts, is down-regulated in several estrogen-related cancer cells, and overexpression of Cav-1 inhibits proliferation of cancer cells and vascular SMCs as well. Therefore, we hypothesize that Cav-1 is down-regulated in human uterine leiomyoma. Western blot using tissues from clinical patients showed that Cav-1 expression was significantly lower or undetectable in uterine leiomyoma compared with their matched myometrium (P leiomyomas was also significantly lower as detected by reverse transcription-quantitative polymerase chain reaction analysis (P = .001). To further study the underlying mechanism, we performed primary cell culture, and found that the expression of Cav-1 remained low in cultured leiomyoma SMCs (P = .009). Serum withdrawal did not change Cav-1 expression in leiomyoma SMCs, but increased expression in myometrial SMCs (P = .006). 17-β estradiol inhibited the expression of Cav-1 protein (P = .047) and mRNA (P = .007) in leiomyoma SMCs, whereas it stimulated expression in myometrial SMCs (P = .043). 17-β estradiol, although activating the mitogen-activated protein kinase pathway in both SMCs, did not stimulate their proliferation. We conclude that human uterine leiomyomas in vitro express low levels of Cav-1, which may result from estrogen inhibition. This effect of estrogen may contribute to the pathogenesis of uterine leiomyoma. Further studies in vivo are needed to verify these results. Copyright © 2014 Elsevier Inc. All rights reserved.

  18. Enhanced caveolin-1 expression increases migration, anchorage-independent growth and invasion of endometrial adenocarcinoma cells

    International Nuclear Information System (INIS)

    Diaz-Valdivia, Natalia; Bravo, Denisse; Huerta, Hernán; Henriquez, Soledad; Gabler, Fernando; Vega, Margarita; Romero, Carmen; Calderon, Claudia; Owen, Gareth I.; Leyton, Lisette; Quest, Andrew F. G.

    2015-01-01

    Caveolin-1 (CAV1) has been implicated both in tumor suppression and progression, whereby the specific role appears to be context dependent. Endometrial cancer is one of the most common malignancies of the female genital tract; however, little is known about the role of CAV1 in this disease. Here, we first determined by immunohistochemistry CAV1 protein levels in normal proliferative human endometrium and endometrial tumor samples. Then using two endometrial cancer cell lines (ECC: Ishikawa and Hec-1A) we evaluated mRNA and protein levels of CAV1 by real time qPCR and Western blot analysis, respectively. The role of CAV1 expression in ECC malignancy was further studied by either inducing its expression in endometrial cancer cells with the tumor promotor 12-O-tetradecanoyl-phorbol-13-acetate (4β-TPA) or decreasing expression using short-hairpin RNA constructs, and then evaluating the effects of these changes on ECC proliferation, transmigration, matrigel invasion, and colony formation in soft agar. Immunohistochemical analysis of endometrial epithelia revealed that substantially higher levels of CAV1 were present in endometrial tumors than the normal proliferative epithelium. Also, in Ishikawa and Hec-1A endometrial cancer cells CAV1 expression was readily detectable. Upon treatment with 4β-TPA CAV1 levels increased and coincided with augmented cell transmigration, matrigel invasion, as well as colony formation in soft agar. Reduction of CAV1 expression using short-hairpin RNA constructs ablated these effects in both cell types whether treated or not with 4β-TPA. Alternatively, CAV1 expression appeared not to modulate significantly proliferation of these cells. Our study shows that elevated CAV1, observed in patients with endometrial cancer, is linked to enhanced malignancy of endometrial cancer cells, as evidenced by increased migration, invasion and anchorage-independent growth. The online version of this article (doi:10.1186/s12885-015-1477-5) contains

  19. Caveolin-1 influences vascular protease activity and is a potential stabilizing factor in human atherosclerotic disease.

    Directory of Open Access Journals (Sweden)

    Juan A Rodriguez-Feo

    Full Text Available Caveolin-1 (Cav-1 is a regulatory protein of the arterial wall, but its role in human atherosclerosis remains unknown. We have studied the relationships between Cav-1 abundance, atherosclerotic plaque characteristics and clinical manisfestations of atherosclerotic disease.We determined Cav-1 expression by western blotting in atherosclerotic plaques harvested from 378 subjects that underwent carotid endarterectomy. Cav-1 levels were significantly lower in carotid plaques than non-atherosclerotic vascular specimens. Low Cav-1 expression was associated with features of plaque instability such as large lipid core, thrombus formation, macrophage infiltration, high IL-6, IL-8 levels and elevated MMP-9 activity. Clinically, a down-regulation of Cav-1 was observed in plaques obtained from men, patients with a history of myocardial infarction and restenotic lesions. Cav-1 levels above the median were associated with absence of new vascular events within 30 days after surgery [0% vs. 4%] and a trend towards lower incidence of new cardiovascular events during longer follow-up. Consistent with these clinical data, Cav-1 null mice revealed elevated intimal hyperplasia response following arterial injury that was significantly attenuated after MMP inhibition. Recombinant peptides mimicking Cav-1 scaffolding domain (Cavtratin reduced gelatinase activity in cultured porcine arteries and impaired MMP-9 activity and COX-2 in LPS-challenged macrophages. Administration of Cavtratin strongly impaired flow-induced expansive remodeling in mice. This is the first study that identifies Cav-1 as a novel potential stabilizing factor in human atherosclerosis. Our findings support the hypothesis that local down-regulation of Cav-1 in atherosclerotic lesions contributes to plaque formation and/or instability accelerating the occurrence of adverse clinical outcomes. Therefore, given the large number of patients studied, we believe that Cav-1 may be considered as a novel target

  20. Radioresistance-related signaling pathways in nasopharyngeal carcinoma cells

    International Nuclear Information System (INIS)

    Guo Ya; Zhu Xiaodong; Qu Song; Su Fang; Wang Qi; Zhang Wei

    2011-01-01

    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 60 Co 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)

  1. Radiation-induced phosphorylation of P53 protects radioresistant Spodoptera frugiperda 9 cells by suppressing microRNA-31-Bim-Bax mediated apoptosis

    International Nuclear Information System (INIS)

    Kumar, Ashish; Chandna, Sudhir

    2016-01-01

    In this study, we demonstrate the role of microRNA-31 (miR-31) in the regulation of radiation-induced apoptosis in model radioresistant insect cell line Sf9 (derived from the ovaries of insect Spodoptera frugiperda) which carries well-conserved apoptotic response. We also investigated the miR-31 expression regulation by p53 homologue in these cells. Our initial in silico analysis confirmed perfect conservation of mature miR-31 across various insect orders, hence we designed biotinylated probes from Bombyx mori sequence for successful detection of miR-31 in Sf9 cells

  2. IGF-IR internalizes with Caveolin-1 and PTRF/Cavin in HaCat cells.

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    Barbara Salani

    Full Text Available BACKGROUND: Insulin-like growth factor-I receptor (IGF-IR is a tyrosine kinase receptor (RTK associated with caveolae, invaginations of the plasma membrane that regulate vesicular transport, endocytosis and intracellular signaling. IGF-IR internalization represents a key mechanism of down-modulation of receptors number on plasma membrane. IGF-IR interacts directly with Caveolin-1 (Cav-1, the most relevant protein of caveolae. Recently it has been demonstrated that the Polymerase I and Transcript Release Factor I (PTRF/Cavin is required for caveolae biogenesis and function. The role of Cav-1 and PTRF/Cavin in IGF-IR internalization is still to be clarified. METHODOLOGY/PRINCIPAL FINDINGS: We have investigated the interaction of IGF-IR with Cav-1 and PTRF/Cavin in the presence of IGF1in human Hacat cells. We show that IGF-IR internalization triggers Cav-1 and PTRF/Cavin translocation from plasma membrane to cytosol and increases IGF-IR interaction with these proteins. In fact, Cav-1 and PTRF/Cavin co-immunoprecipitate with IGF-IR during receptor internalization. We found a different time course of co-immunoprecipitation between IGF-IR and Cav-1 compared to IGF-IR and PTRF/Cavin. Cav-1 and PTRF/Cavin silencing by siRNA differently affect surface IGF-IR levels following IGF1 treatment: Cav-1 and PTRF/Cavin silencing significantly affect IGF-IR rate of internalization, while PTRF/Cavin silencing also decreases IGF-IR plasma membrane recovery. Since Cav-1 phosphorylation could have a role in IGF-IR internalization, the mutant Cav-1Y14F lacking Tyr14 was transfected. Cav-1Y14F transfected cells showed a reduced internalization of IGF-IR compared with cells expressing wild type Cav-1. Receptor internalization was not impaired by Clathrin silencing. These findings support a critical role of caveolae in IGF-IR intracellular traveling. CONCLUSIONS/SIGNIFICANCE: These data indicate that Caveolae play a role in IGF-IR internalization. Based on these findings

  3. Root-Securing and Brain-Fortifying Liquid Upregulates Caveolin-1 in Cell Model with Alzheimer’s Disease through Inhibiting Tau Phosphorylation

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    Depei Yuan

    2017-01-01

    Full Text Available In order to explore the effect of root-securing and brain-fortifying Liquid- (RSBFL- mediated caveolin-1 (CAV-1 on phosphorylation of Tau protein and to uncover underlying mechanisms of RSBFL for the prevention and treatment of Alzheimer’s disease (AD, hippocampal neurons isolated from neonatal SD rats and cultured in DMEM-F12 medium were induced by exogenous Aβ1–42 to establish a cell model with AD. Meanwhile, pEGFP-C1-CAV1 and CAV1-shRNA plasmids were transfected into hippocampal neurons for CAV-1 overexpression and silence, respectively. The serum containing RSBFL was prepared for the intervention of AD model cells. The expression of CAV-1, GSK-3β, and p-Tau in normal hippocampal neurons and AD model cells in the presence of serum containing RSBFL was evaluated. The model hippocampal neurons with AD induced by Aβ1–42 revealed an obvious CAV-1 inhibition, enhanced GSK-3β activity, and abnormal Tau phosphorylation. In contrast, the treatment with serum containing RSBFL could upregulate CAV-1 in AD hippocampal neurons (P<0.05 with improved p-GSK-3βSer9 and reduced p-GSK-3βTyr216 (P<0.01, as well as suppressed abnormal phosphorylation of Tau protein. Therefore, RSBFL has an excellent protective effect on hippocampal neurons through increasing CAV-1 expression, inhibiting GSK-3β activity, and reducing excessive abnormal phosphorylation of Tau protein.

  4. Cellular Prion Protein and Caveolin-1 Interaction in a Neuronal Cell Line Precedes Fyn/Erk 1/2 Signal Transduction

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    Mattia Toni

    2006-01-01

    Full Text Available It has been reported that cellular prion protein (PrPc is enriched in caveolae or caveolae-like domains with caveolin-1 (Cav-1 participating to signal transduction events by Fyn kinase recruitment. By using the Glutathione-S-transferase (GST-fusion proteins assay, we observed that PrPc strongly interacts in vitro with Cav-1. Thus, we ascertained the PrPc caveolar localization in a hypothalamic neuronal cell line (GN11, by confocal microscopy analysis, flotation on density gradient, and coimmunoprecipitation experiments. Following the anti-PrPc antibody-mediated stimulation of live GN11 cells, we observed that PrPc clustered on plasma membrane domains rich in Cav-1 in which Fyn kinase converged to be activated. After these events, a signaling cascade through p42/44 MAP kinase (Erk 1/2 was triggered, suggesting that following translocations from rafts to caveolae or caveolae-like domains PrPc could interact with Cav-1 and induce signal transduction events.

  5. CREB mediates ICAM-3: inducing radio-resistance, cell growth and migration/invasion of the human nonsmall cell lung cancer cell

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    Park, Jong Kuk; So, Kwang Sup; Bae, In Hwa; Um, Hong Duck [Korea Institute of Radiological and Medical Sciences, Seoul (Korea, Republic of)

    2009-05-15

    The ICAM family proteins comprises cell surface molecules that are homologous to NCAM and are members of the single passed type 1 immunoglobulin superfamily (IgSF) that are anchored at the cellular membrane. The ICAM family consists of five subfamilies (ICAM-1 to ICAM-5) of heavily glycosylated cell surface receptors with common functional or structural homology. The extracellular domains of ICAM protein have roles in immune response and inflammation through various cell-cell interactions. The cytoplasmic tail residues of ICAM-3 participate in intracellular signaling such as calcium mobilization and tyrosine phosphorylation. Interestingly, the ICAM proteins appear to have a dual role in cancer. ICAM molecules may target and block tumor progression by stimulation of an immune response such as leukocyte activation. Conversely, other investigations have shown that ICAM molecules are involved in cancer malignancy because their increased expressions are associated with a poor diagnosis, lower survival rates and invasion in several cancers including melanoma, breast cancer and leukemia. We have also reported that an increase of ICAM-3 expression in several cancer cells and specimens of cervical cancer patient induce enhanced radio-resistance by the activation of focal adhesion kinase (FAK) and promote cancer cell proliferation by the activation of Akt and p44/42 MAPK. Therefore, these previous reports imply that ICAM-3 has various undefined roles in cancer. In this study, we investigated whether ICAM-3 increase cell migration and invasion through CREB activation and CREB has a role of increase of radioresistance and cell growth.

  6. Qi-Dong-Huo-Xue-Yin Inhibits Inflammation in Acute Lung Injury in Mice via Toll-Like Receptor 4/Caveolin-1 Signaling

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    Li-Ying Xu

    2018-01-01

    Full Text Available Acute lung injury (ALI is a critical illness with no current effective treatment. Caveolin-1 indirectly activates inflammation-associated signaling pathways by inhibiting endothelial nitric oxide synthase (eNOS. This induces an imbalance between pro- and anti-inflammatory cytokine levels, which are involved in the pathogenesis of ALI. The compound Chinese prescription Qi-Dong-Huo-Xue-Yin (QDHXY is efficacious for ALI treatment via an anti-inflammatory effect; however, the exact underlying mechanism is unknown. Therefore, we explored the protective effect of QDHXY against lipopolysaccharide- (LPS- induced ALI in mice. Histopathological changes in mouse lung tissues were studied. Furthermore, alterations in the serum levels of pro- and anti-inflammatory cytokines were investigated. The levels of tumor necrosis factor- (TNF-α, interleukin- (IL- 6, IL-1β, and interferon-γ-induced protein 10 in bronchoalveolar lavage fluid were measured. Additionally, the expression levels of myeloid differentiation factor 88 (MyD88, caveolin-1, and eNOS were assessed. QDHXY significantly reduced lung infiltration with inflammatory cells and the production of serum pro- and anti-inflammatory cytokines and inhibited the expression of TNF-α, IL-1β, caveolin-1, and MyD88 but not eNOS. These indicate that QDHXY significantly improved the balance between pro- and anti-inflammatory cytokine levels, possibly by inhibiting the caveolin-1 signaling pathway. Therefore, QDHXY may be a potential treatment for ALI.

  7. Tumor cells induce the cancer associated fibroblast phenotype via caveolin-1 degradation: implications for breast cancer and DCIS therapy with autophagy inhibitors.

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    Martinez-Outschoorn, Ubaldo E; Pavlides, Stephanos; Whitaker-Menezes, Diana; Daumer, Kristin M; Milliman, Janet N; Chiavarina, Barbara; Migneco, Gemma; Witkiewicz, Agnieszka K; Martinez-Cantarin, Maria P; Flomenberg, Neal; Howell, Anthony; Pestell, Richard G; Lisanti, Michael P; Sotgia, Federica

    2010-06-15

    Loss of stromal caveolin 1 (Cav-1) is a novel biomarker for cancer-associated fibroblasts that predicts poor clinical outcome in breast cancer and DCIS patients. We hypothesized that epithelial cancer cells may have the ability to drive Cav-1 downregulation in adjacent normal fibroblasts, thereby promoting the cancer associated fibroblast phenotype. To test this hypothesis directly, here we developed a novel co-culture model employing (i) human breast cancer cells (MCF7), and (ii) immortalized fibroblasts (hTERT-BJ1), which are grown under defined experimental conditions. Importantly, we show that co-culture of immortalized human fibroblasts with MCF7 breast cancer cells leads to Cav-1 downregulation in fibroblasts. These results were also validated using primary cultures of normal human mammary fibroblasts co-cultured with MCF7 cells. In this system, we show that Cav-1 downregulation is mediated by autophagic/lysosomal degradation, as pre-treatment with lysosome-specific inhibitors rescues Cav-1 expression. Functionally, we demonstrate that fibroblasts co-cultured with MCF7 breast cancer cells acquire a cancer associated fibroblast phenotype, characterized by Cav-1 downregulation, increased expression of myofibroblast markers and extracellular matrix proteins, and constitutive activation of TGFβ/Smad2 signaling. siRNA-mediated Cav-1 downregulation mimics several key changes that occur in co-cultured fibroblasts, clearly indicating that a loss of Cav-1 is a critical initiating factor, driving stromal fibroblast activation during tumorigenesis. As such, this co-culture system can now be used as an experimental model for generating "synthetic" cancer associated fibroblasts (CAFs). More specifically, these "synthetic" CAFs could be used for drug screening to identify novel therapeutics that selectively target the Cav-1-negative tumor micro-environment. Our findings also suggest that chloroquine, or other autophagy/lysosome inhibitors, may be useful as anti

  8. Characterization of the radioresistance in the radioresistant bacterium deinococcus radiodurans

    International Nuclear Information System (INIS)

    Kong Xiangrong; Du Zeji

    1999-01-01

    The radioresistance of wild type Deinococcus radiodurans KD8301 and the factors affecting the radioresistance were investigated. KH3111 which was a DNA repair mutant of KD8301 (Zeji Du, 1998) was used to be compared with KD8301. Deinococcus radiodurans was discovered by Anderson et al (1956) in X-ray sterilized canned meat that was found to have undergone spoilage. this bacterium and other species of this genus share extreme resistance to ionizing radiation and other agents that damage DNA. Wild type KD8301 and its sensitive mutant KH3111 were irradiated with 60 Co γ-ray at the dose range 0.5 ∼ 10 kGy. Dose-survival fraction curves were made and the radio resistances were determined by LD 99 . The relative contents of DNA in cells were measured by Fluorescence Spectrophotometry (Freedman and Bruce, 1971). The results indicated that wild type KD8301 possesses more radioresistant than its mutant KH3111, LD99 were 9.5 kGy and 2.4 kGy respectively. KD8301 grown at exponential phase showed a decreased resistance to radiation, and the LD99 was 5.1 kGy. No differences of DNA/protein in cells were found between the exponential phase and the stationary phase. The results could be concluded that wild type KD8301 possesses remarkable radioresistance, but this ability was decreased or disappeared after mutation (in KH3111). None DNA relative content other than the growth stages were determinant factors of radioresistance in Deinococcus radiodurans. This results were different from other report (Dickie N et al, 1990). The cellular mechanisms might be the deference's of the bacterium cell morphology between the exponential phase and the stationary phase. Recently, the mutation site of KH3111 which was mutated chemically from wild type KD8301 was identified (Zeji Du, 1998). One base pair changed in the novel gene pprA which was isolated from KD8301 genomic DNA. This point mutation was confirmed to be responsible for the sensitivity of KH3111 to γ-ray and other DNA

  9. Curcumin ameliorates epithelial-to-mesenchymal transition of podocytes in vivo and in vitro via regulating caveolin-1.

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    Sun, Li-na; Chen, Zhi-xin; Liu, Xiang-chun; Liu, Hai-ying; Guan, Guang-ju; Liu, Gang

    2014-10-01

    Epithelial-mesenchymal transition (EMT) is recognized to play a key role in diabetic nephropathy (DN). Curcumin, the main active component of turmeric extracted from the roots of the Curcuma longa plant, has been reported for its anti-fibrotic effects in kidney fibrosis. The purpose of our study was to investigate the effects of curcumin in reversing epithelial-to-mesenchymal transition (EMT) of podocytes in vivo and in vitro. In vivo streptozotocin (STZ)-induced diabetic rats received vehicle or curcumin, and podocytes were treated with high glucose (HG) in the presence or absence of curcumin in vitro. And we investigated the effect of curcumin on HG-induced phosphorylation of cav-1 on the stability cav-1 and β-catenin using immunoprecipitation and fluorescence microscopy analysis. Curcumin treatment dramatically ameliorated metabolic parameters, renal function, morphological parameters in diabetic rats. We found that HG treatment led to significant down-regulation of p-cadherin and synaptopodin, as well as remarkable up-regulation of α-SMA and FSP-1 in vivo and in vitro. Furthermore, curcumin inhibited HG-induced caveolin-1 (cav-1) Tyr(14) phosphorylation associating with the suppression of stabilization of cav-1 and β-catenin. In summary, these findings suggest that curcumin prevents EMT of podocytes, proteinuria, and kidney injury in DN by suppressing the phosphorylation of cav-1, and increasing stabilization of cav-1 and β-catenin. Copyright © 2014 Elsevier Masson SAS. All rights reserved.

  10. Caveolin-1 and glucose transporter 4 involved in the regulation of glucose-deprivation stress in PC12 cells.

    Science.gov (United States)

    Zhang, Qi-Qi; Huang, Liang; Han, Chao; Guan, Xin; Wang, Ya-Jun; Liu, Jing; Wan, Jing-Hua; Zou, Wei

    2015-08-25

    Recent evidence suggests that caveolin-1 (Cav-1), the major protein constituent of caveolae, plays a prominent role in neuronal nutritional availability with cellular fate regulation besides in several cellular processes such as cholesterol homeostasis, regulation of signal transduction, integrin signaling and cell growth. Here, we aimed to investigate the function of Cav-1 and glucose transporter 4 (GLUT4) upon glucose deprivation (GD) in PC12 cells. The results demonstrated firstly that both Cav-1 and GLUT4 were up-regulated by glucose withdrawal in PC12 cells by using Western blot and laser confocal technology. Also, we found that the cell death rate, mitochondrial membrane potential (MMP) and intracellular free Ca(2+) concentration ([Ca(2+)]i) were also respectively changed followed the GD stress tested by CCK8 and flow cytometry. After knocking down of Cav-1 in the cells by siRNA, the level of [Ca(2+)]i was increased, and MMP was reduced further in GD-treated PC12 cells. Knockdown of Cav-1 or methylated-β-Cyclodextrin (M-β-CD) treatment inhibited the expression of GLUT4 protein upon GD. Additionally, we found that GLUT4 could translocate from cytoplasm to cell membrane upon GD. These findings might suggest a neuroprotective role for Cav-1, through coordination of GLUT4 in GD.

  11. Selection of radioresistant tumor cells and presence of ALDH1 activity in vitro

    International Nuclear Information System (INIS)

    Mihatsch, Julia; Toulany, Mahmoud; Bareiss, Petra M.; Grimm, Sabrina; Lengerke, Claudia; Kehlbach, Rainer; Rodemann, H. Peter

    2011-01-01

    Background: Tumor resistance to radiotherapy has been hypothesized to be mediated by a tumor subpopulation, called cancer stem cells (CSCs). Based on the proposed function of CSCs in radioresistance, we explored the cancer stem cell properties of cells selected for radioresistance phenotype. Materials and methods: A549 and SK-BR-3 cells were radioselected with four single doses of 4 or 3 Gy in intervals of 10-12 days and used for colony formation assay and γ-H2AX foci formation assay. Expression of putative stem cell markers, i.e. Sox2, Oct4, ALDH1, and CD133 were analyzed using Western blotting. A549 and SK-BR-3 cells sorted based on their ALDH1 activity were analyzed in clonogenic survival assays. Results: Radioselected A549 and SK-BR-3 cells (A549-R, SK-BR-3-R) showed increased radioresistance and A549-R cells presented enhanced repair of DNA-double strand breaks. PI3K inhibition significantly reduced radioresistance of A549-R cells. Cell line specific differences in the expression of the putative CSC markers Sox2 and Oct4 were observed when parental and radioselected cells were compared but could not be directly correlated to the radioresistant phenotype. However, enzyme activity of the putative stem cell marker ALDH1 showed a correlation to radioresistance. Conclusions: Subpopulations of pooled radioresistant colonies, selected by various radiation exposures were analyzed for the presence of putative stem cell markers. Although the pattern of Sox2, Oct4, and CD133 expression was not generally associated with radioresistance, presence of ALDH1 seems to be indicative for subpopulations with increased radioresistance.

  12. Reduced caveolin-1 promotes hyper-inflammation due to abnormal heme oxygenase-1 localizationin LPS challenged macrophages with dysfunctional CFTR

    Science.gov (United States)

    Zhang, Ping-Xia; Murray, Thomas S.; Villella, Valeria Rachela; Ferrari, Eleonora; Esposito, Speranza; D'Souza, Anthony; Raia, Valeria; Maiuri, Luigi; Krause, Diane S.; Egan, Marie E.; Bruscia, Emanuela M.

    2013-01-01

    We have previously reported that TLR4 signaling is increased in lipopolysaccharide (LPS) -stimulated Cystic Fibrosis (CF) macrophages (MΦs), contributing to the robust production of pro-inflammatory cytokines. The heme oxygenase (HO-1)/carbon monoxide (CO) pathway modulates cellular redox status, inflammatory responses, and cell survival. The HO-1 enzyme, together with the scaffold protein caveolin 1 (CAV-1), also acts as a negative regulator of TLR4 signaling in MΦs. Here, we demonstrate that in LPS-challenged CF MΦs, HO-1 does not compartmentalize normally to the cell surface and instead accumulates intracellularly. The abnormal HO-1 localization in CF MΦs in response to LPS is due to decreased CAV-1 expression, which is controlled by the cellular oxidative state, and is required for HO-1 delivery to the cell surface. Overexpression of HO-1 or stimulating the pathway with CO-releasing molecules (CORM2)enhancesCAV-1 expression in CF MΦs, suggesting a positive-feed forward loop between HO-1/CO induction and CAV-1 expression. These manipulations reestablished HO-1 and CAV-1 cell surface localization in CF MΦ's. Consistent with restoration of HO-1/CAV-1 negative regulation of TLR4 signaling, genetic or pharmacological (CORM2)-induced enhancement of this pathway decreased the inflammatory response of CF MΦs and CF mice treated with LPS. In conclusion, our results demonstrate that the counter-regulatory HO-1/CO pathway, which is critical in balancing and limiting the inflammatory response, is defective in CF MΦs through a CAV-1-dependent mechanism, exacerbating the CF MΦ's response to LPS. This pathway could be a potential target for therapeutic intervention for CF lung disease. PMID:23606537

  13. Expression profiles and functional associations of endogenous androgen receptor and caveolin-1 in prostate cancer cell lines.

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    Bennett, Nigel C; Hooper, John D; Johnson, David W; Gobe, Glenda C

    2014-05-01

    In prostate cancer (PCa) patients, the protein target for androgen deprivation and blockade therapies is androgen receptor (AR). AR interacts with many proteins that function to either co-activate or co-repress its activity. Caveolin-1 (Cav-1) is not found in normal prostatic epithelium, but is found in PCa, and may be an AR co-regulator protein. We investigated cell line-specific signatures and associations of endogenous AR and Cav-1 in six PCa cell lines of known androgen sensitivity: LNCaP (androgen sensitive); 22Rv1 (androgen responsive); PC3, DU145, and ALVA41 (androgen non-reliant); and RWPE1 (non-malignant). Protein and mRNA expression profiles were compared and electron microscopy used to identify cells with caveolar structures. For cell lines expressing both AR and Cav-1, knockdown techniques using small interfering RNA against AR or Cav-1 were used to test whether diminished expression of one affected the other. Co-sedimentation of AR and Cav-1 was used to test their association. A reporter assay for AR genomic activity was utilized following Cav-1 knockdown. AR-expressing LNCaP and 22Rv1 cells had low endogenous Cav-1 mRNA and protein. Cell lines that expressed little or no AR (DU145, PC3, ALVA41, and RWPE1) expressed high endogenous levels of Cav-1. AR knockdown in LNCaP cells had little effect on Cav-1, but Cav-1 knockdown inhibited AR expression and genomic activity. These data show endogenous AR and Cav-1 mRNA and protein expression is inversely related in PCa cells, with Cav-1 acting on the androgen/AR signaling axis possibly as an AR co-activator, demonstrated by diminished AR genomic activity following Cav-1 knockdown. © 2013 Wiley Periodicals, Inc.

  14. Overexpression of Aquaporin-1 and Caveolin-1 in the Rat Urinary Bladder Urothelium Following Bladder Outlet Obstruction

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    Sun-Ouck Kim

    2013-12-01

    Full Text Available Purpose This study was designed to investigate the effect of detrusor overactivity induced by partial bladder outlet obstruction (BOO on the expression of aquaporin 1 (AQP1 and caveolin 1 (CAV1 in the rat urinary bladder, and to determine the role of these molecules in detrusor overactivity. Methods Female Sprague-Dawley rats were divided into control (n=30 and experimental (n=30 groups. The BOO group underwent partial BOO, and the control group underwent a sham operation. After 4 weeks, an urodynamic study was performed to measure the contraction interval and contraction pressure. The expression and cellular localization of AQP1 and CAV1 were determined by western blot and immunofluorescence experiments in the rat urinary bladder. Results In cystometrograms, the contraction interval was significantly lower in the BOO group (2.9±1.5 minutes than in the control group (6.7±1.0 minutes (P<0.05. Conversely, the average contraction pressure was significantly higher in the BOO group (21.2±3.3 mmHg than in the control group (13.0±2.5 mmHg (P<0.05. AQP1 and CAV1 were coexpressed in the capillaries, arterioles, and venules of the suburothelial layer. AQP1 and CAV1 protein expression was significantly increased in the BOO rats compared to the control rats (P<0.05. Conclusions Detrusor overactivity induced by BOO causes a significant increase in the expression of AQP1 and CAV1, which were coexpressed in the suburothelial microvasculature. This finding suggests that AQP1 and CAV1 might be closely related to bladder signal activity and may have a functional role in BOO-associated detrusor overactivity.

  15. Genotypic frequency of Caveolin-1 (CAV1 T29107A polymorphism in the Iranian patients with breast cancer

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    Ahmad Hamta

    2016-09-01

    Full Text Available Introduction: Caveolin-1 (Cav-1 is a scaffolding protein found in special structures of plasma membrane, known as Caveolae. Cav-1 can regulate many intracellular processes, including signal transmission and cholesterol metabolism. This protein plays an important role in the growth and differentiation of breast tissue and acts as a tumor suppressor gene as well. The aim of this study was to determine the genotypic frequency of Cav-1 T29107A (rs7804372 polymorphism and its association with susceptibility to breast cancer among the female population in Kermanshah, Iran. Methods: A total of 120 patients with breast cancer and an equal number of non-cancer individuals (control group, matched for age and gender with the patients, were selected in this study. The paraffin tissues of the patients from 2006 to 2013 were collected from Imam Reza hospital, Kermanshah, and 2.5 cc blood sample was taken from non-cancer individuals. The genomic DNA was extracted from paraffin tissues and blood by salting out method. The genotype of samples was determined by RFLP-PCR method, and Sau3A1 enzyme was used for RFLP analysis. Results: The distribution of Cav-1 T29107A genotype was found to be significantly different between breast cancer patients and control group (p=0.004. Among the patients, 84 (70% samples had genotype TT, 29 (24.78% genotype AT and 7 (5.83% genotype AA. As for the control group, however, 59 (49.17% samples had genotype TT, 49 (40.83% genotype AT and 12 (10% genotype AA. Conclusion: The results of this study showed that genotype TT is associated with an increased risk of susceptibility to breast cancer.

  16. Neuron-specific caveolin-1 overexpression improves motor function and preserves memory in mice subjected to brain trauma.

    Science.gov (United States)

    Egawa, Junji; Schilling, Jan M; Cui, Weihua; Posadas, Edmund; Sawada, Atsushi; Alas, Basheer; Zemljic-Harpf, Alice E; Fannon-Pavlich, McKenzie J; Mandyam, Chitra D; Roth, David M; Patel, Hemal H; Patel, Piyush M; Head, Brian P

    2017-08-01

    Studies in vitro and in vivo demonstrate that membrane/lipid rafts and caveolin (Cav) organize progrowth receptors, and, when overexpressed specifically in neurons, Cav-1 augments neuronal signaling and growth and improves cognitive function in adult and aged mice; however, whether neuronal Cav-1 overexpression can preserve motor and cognitive function in the brain trauma setting is unknown. Here, we generated a neuron-targeted Cav-1-overexpressing transgenic (Tg) mouse [synapsin-driven Cav-1 (SynCav1 Tg)] and subjected it to a controlled cortical impact model of brain trauma and measured biochemical, anatomic, and behavioral changes. SynCav1 Tg mice exhibited increased hippocampal expression of Cav-1 and membrane/lipid raft localization of postsynaptic density protein 95, NMDA receptor, and tropomyosin receptor kinase B. When subjected to a controlled cortical impact, SynCav1 Tg mice demonstrated preserved hippocampus-dependent fear learning and memory, improved motor function recovery, and decreased brain lesion volume compared with wild-type controls. Neuron-targeted overexpression of Cav-1 in the adult brain prevents hippocampus-dependent learning and memory deficits, restores motor function after brain trauma, and decreases brain lesion size induced by trauma. Our findings demonstrate that neuron-targeted Cav-1 can be used as a novel therapeutic strategy to restore brain function and prevent trauma-associated maladaptive plasticity.-Egawa, J., Schilling, J. M., Cui, W., Posadas, E., Sawada, A., Alas, B., Zemljic-Harpf, A. E., Fannon-Pavlich, M. J., Mandyam, C. D., Roth, D. M., Patel, H. H., Patel, P. M., Head, B. P. Neuron-specific caveolin-1 overexpression improves motor function and preserves memory in mice subjected to brain trauma. © FASEB.

  17. γ-Oryzanol reduces caveolin-1 and PCGEM1 expression, markers of aggressiveness in prostate cancer cell lines.

    Science.gov (United States)

    Hirsch, Gabriela E; Parisi, Mariana M; Martins, Leo A M; Andrade, Claudia M B; Barbé-Tuana, Florencia M; Guma, Fátima T C R

    2015-06-01

    Prostate cancer is a leading cause of death among men due to the limited number of treatment strategies available for advanced disease. γ-oryzanol is a component of rice bran, rich in phytosterols, known for its antioxidant, anti-carcinogenic and endocrinological effects. It is known that γ-oryzanol may affect prostate cancer cells through the down regulation of the antioxidant genes and that phytosterols have anti-proliferative and apoptotic effects. There are evidences showing that some of the components of γ-oryzanol can modulate genes involved in the development and progression of prostate cancer, as caveolin-1 (Cav-1) and prostate specific androgen-regulated gene (PCGEM1). To determine the effects of γ-oryzanol on prostate cancer cell survival we evaluated the cell viability and biomass by MTT and sulforhodamine B assays, respectively. Cell death, cell cycle and pERK1/2 activity were assessed by flow cytometry. The changes in gene expression involved in the survival and progression of prostate cancer cav-1 and PCGEM1 genes were evaluated by quantitative real time reverse transcriptase polymerase chain reaction (RT-PCR) and cav-1 protein by immunofluorescence followed by confocal microscopy analysis. We found that γ-oryzanol decreases cell viability and culture biomass by apoptosis and/or necrosis death in androgen unresponsive (PC3 and DU145) and responsive (LNCaP) cell lines, and signals through pERK1/2 in LNCaP and DU145 cells. γ-oryzanol also appears to block cell cycle progression at the G2/M in PC3 and LNCaP cells and at G0/G1 in DU145 cells. These effects were accompanied by a down regulation in the expression of the cav-1 in both androgen unresponsive cell lines and PCGEM1 gene in DU145 and LNCaP cells. In summary, we used biochemical and genetics approaches to demonstrate that γ-oryzanol show a promising adjuvant role in the treatment of prostate cancer. © 2015 Wiley Periodicals, Inc.

  18. Stress and radioresistance (genetic aspects)

    International Nuclear Information System (INIS)

    Lyubaschevsky, N.M.; Grigorkina, E.B.

    1995-01-01

    Inbred mice and randomly bred stock were exposed to long-term adrenaline and hypothermia stress effects for unification of their functional status, followed by acute total gamma irradiation by equal-effect doses (LD 50/30 ). The significant reduction of lethality distribution in inbred mice after combined stress and radiation effects was observed. The spread of lethality in random bred stock was increased as compared to the control group. The post-irradiation mortality in experimental animals differed only slightly from the values in the control groups. Conclusions are drawn about the principal meaning of genotype in radiosensitivity, about the role of an organism's functional status in determination of death date and about the possible epigenetic structuralisation of linear mice by radioresistance. (Author)

  19. Radiations, human cancerization and radioresistance

    International Nuclear Information System (INIS)

    Vuillaume, M.

    1991-01-01

    Active oxygen species have been implicated in inflammatory diseases, cellular transformation and carcinogenesis. Experiments studying their direct (for instance, by ionizing radiation) or indirect influence (for instance, by the decrease(s) in activity of cellular defence enzymes), in vivo, and/or, in cell cultures (fibroblasts, keratinocytes, hepatocytes,...) have been positive. To the contrary, reactions or products, which decrease level(s) of free radicals/H 2 O 2 (i) directly, (ii) indirectly by an increase of SOD, catalase, and peroxydase activites suppress the above-described phenomena. This is the case for the domain number 2 (that contains copper, MW 53KDa) of the Scorpion's blood pigment (hemocyanin), which possesses SOD-, catalase-, and peroxydase-like properties, resistant to, at least, 4000 Gy, and thus may explain the especially high radioresistance of scorpions. Enzymatic decrease(s) and the domain number 2 of hemocyanin are under current investigation in several laboratories [fr

  20. Radioresistance in Central Asian tortoise

    Energy Technology Data Exchange (ETDEWEB)

    Turdyev, A.A.; Bogdanova-Berezovskaya, I.G.; Dvornikova, L.I.

    Season-related studies were conducted on the phenomenal radioresistance of the Central Asian tortoise (Testudo horsfieldii), in order to obtain greater understanding of the factors that determine this physiological uniqueness. Test animals were exposed to gamma radiation from a Co-60 source with dosages ranging from 12.9 to 25.8 Cl/kg in the spring, summer, fall, and winter. Using Pearson's ..gamma..-distribution coefficient calculations of the mean lethal dose for the season yielded 16.33 Cl/kg for winter, 10.94 Cl/kg for spring, 7.1 Cl/kg for summer, and 19.71 Cl/kg for fall. The animals were thus seen to be most susceptible to radiation damage in the spring and summer. Correlation with histological and hematological studies showed that animals irradiated in spring and summer succumbed as a result of damage to the GI and the hematopoietic systems, whereas animals that died as a result of irradiation during the fall and winter season did so because of depletion of hepatic glycogen stores. 5 references, 1 figure.

  1. Fractionated irradiation-induced EMT-like phenotype conferred radioresistance in esophageal squamous cell carcinoma

    Science.gov (United States)

    Zhang, Hongfang; Luo, Honglei; Jiang, Zhenzhen; Yue, Jing; Hou, Qiang; Xie, Ruifei; Wu, Shixiu

    2016-01-01

    The efficacy of radiotherapy, one major treatment modality for esophageal squamous cell carcinoma (ESCC) is severely attenuated by radioresistance. Epithelial-to-mesenchymal transition (EMT) is a cellular process that determines therapy response and tumor progression. However, whether EMT is induced by ionizing radiation and involved in tumor radioresistance has been less studied in ESCC. Using multiple fractionated irradiation, the radioresistant esophageal squamous cancer cell line KYSE-150R had been established from its parental cell line KYSE-150. We found KYSE-150R displayed a significant EMT phenotype with an elongated spindle shape and down-regulated epithelial marker E-cadherin and up-regulated mesenchymal marker N-cadherin in comparison with KYSE-150. Furthermore, KYSE-150R also possessed some stemness-like properties characterized by density-dependent growth promotion and strong capability for sphere formation and tumorigenesis in NOD-SCID mice. Mechanical studies have revealed that WISP1, a secreted matricellular protein, is highly expressed in KYSE-150R and mediates EMT-associated radioresistance both in ESCC cells and in xenograft tumor models. Moreover, WISP1 has been demonstrated to be closely associated with the EMT phenotype observed in ESCC patients and to be an independent prognosis factor of ESCC patients treated with radiotherapy. Our study highlighted WISP1 as an attractive target to reverse EMT-associated radioresistance in ESCC and can be used as an independent prognostic factor of patients treated with radiotherapy. PMID:27125498

  2. Fractionated irradiation-induced EMT-like phenotype conferred radioresistance in esophageal squamous cell carcinoma

    International Nuclear Information System (INIS)

    Zhang, Hongfang; Luo, Honglei; Jiang, Zhenzhen; Yue, Jing; Hou, Qiang; Xie, Ruifei; Wu, Shixiu

    2016-01-01

    The efficacy of radiotherapy, one major treatment modality for esophageal squamous cell carcinoma (ESCC) is severely attenuated by radioresistance. Epithelial-to-mesenchymal transition (EMT) is a cellular process that determines therapy response and tumor progression. However, whether EMT is induced by ionizing radiation and involved in tumor radioresistance has been less studied in ESCC. Using multiple fractionated irradiation, the radioresistant esophageal squamous cancer cell line KYSE-150R had been established from its parental cell line KYSE-150. We found KYSE-150R displayed a significant EMT phenotype with an elongated spindle shape and down-regulated epithelial marker E-cadherin and up-regulated mesenchymal marker N-cadherin in comparison with KYSE-150. Furthermore, KYSE-150R also possessed some stemness-like properties characterized by density-dependent growth promotion and strong capability for sphere formation and tumorigenesis in NOD-SCID mice. Mechanical studies have revealed that WISP1, a secreted matricellular protein, is highly expressed in KYSE-150R and mediates EMT-associated radioresistance both in ESCC cells and in xenograft tumor models. Moreover, WISP1 has been demonstrated to be closely associated with the EMT phenotype observed in ESCC patients and to be an independent prognosis factor of ESCC patients treated with radiotherapy. Our study highlighted WISP1 as an attractive target to reverse EMT-associated radioresistance in ESCC and can be used as an independent prognostic factor of patients treated with radiotherapy

  3. Thermoresistance in radioresistant strains of 'Drosophila nebulosa'

    International Nuclear Information System (INIS)

    Kratz, F.L.

    1977-01-01

    The detection of thermoresistance in radioresistant strains of 'D. nebulosa' is described, as well as some conclusions on the genetic nature of these differences are presented. The strains used in this experiment were MF 204, from 'Morro de Ferro', in Pocos de Caldas (MG) (one of the biggest radioactive anomalies in the world) whose radioresistance is due to its additive genetic components (Kratz, 1973 and 1975); 85(87) R, an induced radioresistant strain; and MF K a control 'pooled' strain obtained near 'Morro do Ferro'. Survival tests, 72 hours after temperature shocks, performed in the interval of 36 0 C to 39 0 C showed a decreasing gradient of thermoresistance with the following regression coefficients: MF 204 b= - 5,4; 85(87)R b= - 7,2 and MF K b= - 7,9. Bifactorial analysis (strains and sexes) performed at 38 0 C and 39 0 C confirmed differences among strains (P [pt

  4. Role of lipids in bacterial radioresistance

    International Nuclear Information System (INIS)

    Abushady, M.R.; Fawkia, M.E.; Tawfik, Z.S.

    1992-01-01

    The radioresistance of three bacterial isolates was determined. S. aureus was the most sensitive one (D 1 0 value 0.14 KGy), B. coagulans was moderate resistant (D 1 0 value 3.3 KGy) and the most resistant one was B.megaterium (D 1 0 value 3.7 KGy). Total lipids and lipid patterns of these bacteria were determined and the role of lipids in radioresistance was investigated. Least amount of total lipids was detected in the most sensitive organism (S. aureus). The increase in the bacterial content of total lipids was concomitant with high degrees of radioresistance. The most resistant organism (B. megaterium was characterized by high content of methyl esters of fatty acids, phosphatidylcholine and phosphatidylethanolamine, followed by appreciable amounts in the moderate resistant (B. coagulans) and the least amounts were detected in the most sensitive organism (S.aureus).6 fig., 3 tab

  5. The problem: Tumor radioresistance in clinical radiotherapy

    International Nuclear Information System (INIS)

    Peters, L.J.; Withers, H.R.; Thames, H.D.; Fletcher, G.H.; M.D. Anderson Hospital and Tumor Inst., Houston, TX)

    1983-01-01

    Tumor radioresistance in clinical radiotherapy implies failure to achieve local-regional disease control with radiation doses producing an acceptable degree of morbidity. Such radioresistance may be due to many different causes (biological and technical) which are reviewed in terms of possible remedial actions. Dose-response relationships for human cancers suggest that, in many sites, tumors are heterogeneous with respect to their cure-limiting characteristics. The case is developed that unless the predominant cure-limiting factor can be predicted, little benefit may be seen in trials of new treatment strategies using heterogeneous tumor populations. The fundamental problem of clinical radioresistance is therefore perceived as the inability to identify predictively its cause in the individual patient

  6. [Unique properties of highly radioresistant bacteria].

    Science.gov (United States)

    Romanovskaia, V A; Rokitko, P V; Malashenko, Iu R

    2000-01-01

    In connection with the Chernobyl Nuclear Power Plant (ChNPP) accident and the negative ecological after-effects for biota in this zone the interest has arisen to radioresistant bacteria, as to the most dynamic model of the given ecosystem, and to mechanisms which provide resistance of bacteria to ionizing radiation. The analysis of published data has shown that the radioresistant bacteria are not interrelated taxonomically and phylogenetically. The extreme radioresistant bacteria are represented by the Deinococcus species, which form a group phylogenetically close to the line Thermus-Meiothermus. Other radioresistant bacteria are the representatives of the genera Rubrobacter, Methylobacterium, Kocuria, Bacillus and some archebacteria. Data on natural habitats, of radioresistant bacteria are not numerous. In a number of cases it is difficult to distinguish their natural habitats, as they were isolated from the samples which were previously exposed to X-ray or gamma-irradiation, or from the ecosystems with the naturally raised radioactivity. To understand the strategy of survival of radioresistant bacteria, we briefly reviewed the mechanism of action of various species of radiation on cells and macromolecules; physiological signs of the cell damage caused by radiation; mechanisms eliminating (repairing) these damages. More details on mechanisms of the DNA repair in D. radiodurans are described. The extreme resistance of D. radiodurans to the DNA damaging factors is defined by 1) repair mechanisms which fundamentally differ from those in other procaryotes; 2) ability to increase the efficiency of a standard set of the DNA repairing proteins. Literary and own data on the effect of radiation on survival of various groups of bacteria in natural ecosystems are summarized. The ecological consequences of the ChNPP accident for soil bacteria in this region were estimated. The reduction of the number of soil bacteria and recession of microbial diversity under the effect of

  7. Radioresistance of immunized animals in internal irradiation

    International Nuclear Information System (INIS)

    Kal'nitskij, S.A.; Ponomareva, T.V.; Shubik, V.M.

    1981-01-01

    The influence of an immunization with bacterial vaccines and antimeasles-gamma-globulin on the radioresistance of raceless white mice was studied. In the vaccinated animals a higher survival rate and duration of life, a better general condition and a better curve of weight and stronger physical stamina were stated compared to the merely irradiated mice. The higher radioresistance is ascribed to the stimulation of cellular and humoral factors of the unspecific protection against infection, to the repair of the lymphoid tissue of the immunized animals and to the decrease in autosensibilization. (author)

  8. Curcumin Decreases Hyperphosphorylation of Tau by Down-Regulating Caveolin-1/GSK-3β in N2a/APP695swe Cells and APP/PS1 Double Transgenic Alzheimer's Disease Mice.

    Science.gov (United States)

    Sun, Jieyun; Zhang, Xiong; Wang, Chen; Teng, Zhipeng; Li, Yu

    2017-01-01

    Caveolin-1, the marker protein of membranal caveolae, is not only involved in cholesterol regulation, but also participates in the cleavage of amyloid [Formula: see text]-protein precursor (APP) and the generation of [Formula: see text]-amyloid peptide. It has been reported to be tightly related with Tau. In our previous studies, curcumin has been confirmed to play a neuroprotective role in Alzheimer's disease (AD), but its effects on Caveolin-1, Tau and their correlation, and the mechanism is still unknown. As such, in the present study, N2a/WT cells, N2a/APP695swe cell and six-month-old APP/PS1 double transgenic mice were enrolled. After curcumin treatment, the expression of Caveolin-1, Tau and their relationship was detected, and the potential mechanisms were explored. The results showed that in the N2a/APP695swe cells, curcumin not only decreased the number of caveolae, but also made their membrane to be thinner; and curcumin could decreased the expression of phosphorylated Tau (P-Tau(ser404)/Tau) and Caveolin-1 ([Formula: see text]), but the expression of phosphorylated GSK-3[Formula: see text] (P-GSK-3[Formula: see text]/GSK-3[Formula: see text] was increased ([Formula: see text]). In APP/PS1 transgenic mice, the same results were observed. Taken together, our data suggest that curcumin may play an important role in AD via reducing Caveolin-1, inactivating GSK-3[Formula: see text] and inhibiting the abnormal excessive phosphorylation of Tau, which will provide a new theory for AD treatment with curcumin.

  9. Radioresistance and radiosensitivity in Drosophila melanogaster

    International Nuclear Information System (INIS)

    Reguly, M.L.

    1983-01-01

    Studying the mechanisms controlling radioresistant in Drosophila the sensibility of four strains of Drosophila melanogaster to sex-linked recessive lethal mutations induced by 5kR Cobalt-60 gamma radiation and 0,006 M EMS or 0,25% of caffeine was determined. (M.A.C.) [pt

  10. Radioresistance and radiosensitivity in Drosophila melanogaster

    International Nuclear Information System (INIS)

    Reguly, M.L.; Marques, E.K.

    1987-01-01

    The mechanisms of radioresistance in Drosophila are studied. The mutagenic effects of 5KR of 60 Cobalt gamma radiation and of 0,006M dose of ethyl methanesulfonate (EMS) on four D. Melanogaster strains (RC 1 , CO 3 , BUE and LEN) are investigated. (M.A.C.) [pt

  11. Exercise-Induced Changes in Caveolin-1, Depletion of Mitochondrial Cholesterol, and the Inhibition of Mitochondrial Swelling in Rat Skeletal Muscle but Not in the Liver

    Directory of Open Access Journals (Sweden)

    Damian Jozef Flis

    2016-01-01

    Full Text Available The reduction in cholesterol in mitochondria, observed after exercise, is related to the inhibition of mitochondrial swelling. Caveolin-1 (Cav-1 plays an essential role in the regulation of cellular cholesterol metabolism and is required by various signalling pathways. Therefore, the aim of this study was to investigate the effect of prolonged swimming on the mitochondrial Cav-1 concentration; additionally, we identified the results of these changes as they relate to the induction of changes in the mitochondrial swelling and cholesterol in rat skeletal muscle and liver. Male Wistar rats were divided into a sedentary control group and an exercise group. The exercised rats swam for 3 hours and were burdened with an additional 3% of their body weight. After the cessation of exercise, their quadriceps femoris muscles and livers were immediately removed for experimentation. The exercise protocol caused an increase in the Cav-1 concentration in crude muscle mitochondria; this was related to a reduction in the cholesterol level and an inhibition of mitochondrial swelling. There were no changes in rat livers, with the exception of increased markers of oxidative stress in mitochondria. These data indicate the possible role of Cav-1 in the adaptive change in the rat muscle mitochondria following exercise.

  12. Radioresistance increase in polymers at high pressures

    International Nuclear Information System (INIS)

    Milinchuk, V.; Kirjukhin, V.; Klinshpont, E.

    1977-01-01

    The effect was studied of very high pressures ranging within 100 and 2,700 MPa on the radioresistance of polytetrafluoroethylene, polypropylene and polyethylene in gamma irradiation. For experiments industrial polymers in the shape of blocks, films and fibres were used. It is shown that in easily breakable polymers, such as polytetrafluoroethylene and polypropylene 1.3 to 2 times less free radicals are formed as a result of gamma irradiation and a pressure of 150 MPa than at normal pressure. The considerably reduced radiation-chemical formation of radicals and the destruction suppression by cross-linking in polymers is the evidence of the polymer radioresistance in irradiation at high pressures. (J.B.)

  13. Radioresistance and immunization effectiveness under internal irradiation

    International Nuclear Information System (INIS)

    Kal'nitskij, S.A.

    1978-01-01

    The effect of preliminary immunization on the radioresistance of mice to internal irradiation from incorporated 137 Cs or 90 Sr was studied, and it was found that a preliminary single immunization with bacterial vaccines had a favorable effect on the outcome of radiation injury. The present results suggested that vaccination had a very pronounced radioprotective effect and so may be used as a means of biologic protection from internal irradiation

  14. Ivastimul used to increase radioresistance of mice

    International Nuclear Information System (INIS)

    Rotkovska, D.; Vacek, A.; Bartonickova, A.

    1989-01-01

    A study was made of the effect of ivastimul (IS), an aqueous extract from unicellular Chlorella algae, on the radioresistance and some haemopoiesis parameters of mice exposed to 60 Co-γ-radiation. With median and absolutely lethal radiation doses, IS was shown to produce a pronounced protective effect displayed by the increased survival rate. With sublethal doses, IS elevated the postirradiation formation of endogenous colonies and restoration of bone marrow and spleen cellularity and spleen mass

  15. HIF-1 and NDRG2 contribute to hypoxia-induced radioresistance of cervical cancer Hela cells

    International Nuclear Information System (INIS)

    Liu, Junye; Zhang, Jing; Wang, Xiaowu; Li, Yan; Chen, Yongbin; Li, Kangchu; Zhang, Jian; Yao, Libo; Guo, Guozhen

    2010-01-01

    Hypoxia inducible factor 1 (HIF-1), the key mediator of hypoxia signaling pathways, has been shown involved in hypoxia-induced radioresistance. However, the underlying mechanisms are unclear. The present study demonstrated that both hypoxia and hypoxia mimetic cobalt chloride could increase the radioresistance of human cervical cancer Hela cells. Meanwhile, ectopic expression of HIF-1 could enhance the resistance of Hela cells to radiation, whereas knocking-down of HIF-1 could increase the sensitivity of Hela cells to radiation in the presence of hypoxia. N-Myc downstream-regulated gene 2 (NDRG2), a new HIF-1 target gene identified in our lab, was found to be upregulated by hypoxia and radiation in a HIF-1-dependent manner. Overexpression of NDRG2 resulted in decreased sensitivity of Hela cells to radiation while silencing NDRG2 led to radiosensitization. Moreover, NDRG2 was proved to protect Hela cells from radiation-induced apoptosis and abolish radiation-induced upregulation of Bax. Taken together, these data suggest that both HIF-1 and NDRG2 contribute to hypoxia-induced tumor radioresistance and that NDRG2 acts downstream of HIF-1 to promote radioresistance through suppressing radiation-induced Bax expression. It would be meaningful to further explore the clinical application potential of HIF-1 and NDRG2 blockade as radiosensitizer for tumor therapy.

  16. Beclin1-induced autophagy abrogates radioresistance of lung cancer cells by suppressing osteopontin

    International Nuclear Information System (INIS)

    Chang, Seung-Hee; Minai-Tehrani, Arash; Shin, Ji-Young

    2012-01-01

    Osteopontin (OPN) serves as an indicator of resistance to radiotherapy. However, the role of OPN in the development of acquired radioresistance in human lung cancer cells has not yet been fully elucidated. Therefore, the potential importance of OPN as a marker of lung cancer with a potential significant role in the development of radioresistance against repeated radiotherapy has prompted us to define the pathways by which OPN regulates lung cancer cell growth. In addition, autophagy has been reported to play a key role in the radiosensitization of cancer cells. Here, we report that increased OPN expression through induction of nuclear p53 following irradiation was inhibited by exogenous beclin-1 (BECN1). Our results clearly show that BECN1 gene expression led to induction of autophagy and inhibition of cancer cell growth and angiogenesis. Our results suggest that the induction of autophagy abrogated the radioresistance of the cancer cells. Interestingly, we showed that knockdown of OPN by lentivirus-mediated shRNA induced the autophagy of human lung cancer cell. Taken together, these results suggest that OPN and BECN1 can be molecular targets for overcoming radioresistance by controlling autophagy. (author)

  17. Targeting the AKT/GSK3β/Cyclin D1/Cdk4 Survival Signaling Pathway for Eradication of Tumor Radioresistance Acquired by Fractionated Radiotherapy

    International Nuclear Information System (INIS)

    Shimura, Tsutomu; Kakuda, Satoshi; Ochiai, Yasushi; Kuwahara, Yoshikazu; Takai, Yoshihiro; Fukumoto, Manabu

    2011-01-01

    Purpose: Radioresistance is a major cause of treatment failure of radiotherapy (RT) in human cancer. We have recently revealed that acquired radioresistance of tumor cells induced by fractionated radiation is attributable to cyclin D1 overexpression as a consequence of the downregulation of GSK3β-dependent cyclin D1 proteolysis mediated by a constitutively activated serine-threonine kinase, AKT. This prompted us to hypothesize that targeting the AKT/GSK3β/cyclin D1 pathway may improve fractionated RT by suppressing acquired radioresistance of tumor cells. Methods and Materials: Two human tumor cell lines with acquired radioresistance were exposed to X-rays after incubation with either an AKT inhibitor, AKT/PKB signaling inhibitor-2 (API-2), or a Cdk4 inhibitor (Cdk4-I). Cells were then subjected to immunoblotting, clonogenic survival assay, cell growth analysis, and cell death analysis with TUNEL and annexin V staining. In vivo radiosensitivity was assessed by growth of human tumors xenografted into nude mice. Results: Treatment with API-2 resulted in downregulation of cyclin D1 expression in cells with acquired radioresistance. Cellular radioresistance disappeared completely both in vitro and in vivo with accompanying apoptosis when treated with API-2. Furthermore, inhibition of cyclin D1/Cdk4 by Cdk4-I was sufficient for abolishing radioresistance. Treatment with either API-2 or Cdk4-I was also effective in suppressing resistance to cis-platinum (II)-diamine-dichloride in the cells with acquired radioresistance. Interestingly, the radiosensitizing effect of API-2 was canceled by overexpression of cyclin D1 whereas Cdk4-I was still able to sensitize cells with cyclin D1 overexpression. Conclusion: Cyclin D1/Cdk4 is a critical target of the AKT survival signaling pathway responsible for tumor radioresistance. Targeting the AKT/GSK3β/cyclin D1/Cdk4 pathway would provide a novel approach to improve fractionated RT and would have an impact on tumor eradication in

  18. Quantum Dots-Based Immunofluorescent Imaging of Stromal Fibroblasts Caveolin-1 and Light Chain 3B Expression and Identification of Their Clinical Significance in Human Gastric Cancer

    Directory of Open Access Journals (Sweden)

    Honglei Chen

    2012-10-01

    Full Text Available Caveolin-1 (Cav-1 expression deficiency and autophagy in tumor stromal fibroblasts (hereafter fibroblasts are involved in tumor proliferation and progression, particularly in breast and prostate cancer. The aim of this study was to detect the expression of fibroblastic Cav-1 and LC3B, markers of autophagy, in gastric cancer (GC and to analyze their clinical significances. Furthermore, because Epstein-Barr virus (EBV-associated GC (EBVaGC is a unique subtype of GC; we compared the differential expression of fibroblastic Cav-1 and LC3B in EBVaGC and non-EBVaGC. Quantum dots (QDs-based immunofluorescence histochemistry was used to examine the expression of fibroblastic Cav-1 and LC3B in 118 cases of GC with adequate stroma. QDs-based double immunofluorescence labeling was performed to detect the coexpression of Cav-1 and LC3B proteins. EBV-encoded small RNA was detected by QDs-based fluorescence in situ hybridization to identify EBVaGC. Multivariate analysis indicated that low fibroblastic Cav-1 level was an independent prognosticator (p = 0.029 that predicted poorer survival of GC patients. Positive fibroblastic LC3B was correlated with lower invasion (p = 0.032 and was positively associated with Cav-1 expression (r = 0.432, p < 0.001. EBV infection did not affect fibroblastic Cav-1 and LC3B expression. In conclusion, positive fibroblastic LC3B correlates with lower invasion, and low expression of fibroblastic Cav-1 is a novel predictor of poor GC prognosis.

  19. A disease-associated frameshift mutation in caveolin-1 disrupts caveolae formation and function through introduction of a de novo ER retention signal.

    Science.gov (United States)

    Copeland, Courtney A; Han, Bing; Tiwari, Ajit; Austin, Eric D; Loyd, James E; West, James D; Kenworthy, Anne K

    2017-11-01

    Caveolin-1 (CAV1) is an essential component of caveolae and is implicated in numerous physiological processes. Recent studies have identified heterozygous mutations in the CAV1 gene in patients with pulmonary arterial hypertension (PAH), but the mechanisms by which these mutations impact caveolae assembly and contribute to disease remain unclear. To address this question, we examined the consequences of a familial PAH-associated frameshift mutation in CAV1 , P158PfsX22, on caveolae assembly and function. We show that C-terminus of the CAV1 P158 protein contains a functional ER-retention signal that inhibits ER exit and caveolae formation and accelerates CAV1 turnover in Cav1 -/- MEFs. Moreover, when coexpressed with wild-type (WT) CAV1 in Cav1 -/- MEFs, CAV1-P158 functions as a dominant negative by partially disrupting WT CAV1 trafficking. In patient skin fibroblasts, CAV1 and caveolar accessory protein levels are reduced, fewer caveolae are observed, and CAV1 complexes exhibit biochemical abnormalities. Patient fibroblasts also exhibit decreased resistance to a hypo-osmotic challenge, suggesting the function of caveolae as membrane reservoir is compromised. We conclude that the P158PfsX22 frameshift introduces a gain of function that gives rise to a dominant negative form of CAV1, defining a new mechanism by which disease-associated mutations in CAV1 impair caveolae assembly. © 2017 Copeland, Han, et al. This article is distributed by The American Society for Cell Biology under license from the author(s). Two months after publication it is available to the public under an Attribution–Noncommercial–Share Alike 3.0 Unported Creative Commons License (http://creativecommons.org/licenses/by-nc-sa/3.0).

  20. Pioglitazone, a PPARγ Agonist, Upregulates the Expression of Caveolin-1 and Catalase, Essential for Thyroid Cell Homeostasis: A Clue to the Pathogenesis of Hashimoto's Thyroiditis.

    Science.gov (United States)

    Werion, Alexis; Joris, Virginie; Hepp, Michael; Papasokrati, Lida; Marique, Lancelot; de Ville de Goyet, Christine; Van Regemorter, Victoria; Mourad, Michel; Lengelé, Benoit; Daumerie, Chantal; Marbaix, Etienne; Brichard, Sonia; Many, Marie-Christine; Craps, Julie

    2016-09-01

    Peroxisome proliferator-activated receptor γ (PPARγ) is a transcription factor that regulates the expression of multiple target genes involved in several metabolic pathways as well as in inflammation. The expression and cell localization of caveolin-1 (Cav-1), thyroperoxidase (TPO), and dual oxidase (DUOX), involved in extracellular iodination, is modulated by Th1 cytokines in human normal thyroid cells and in Hashimoto's thyroiditis (HT). The objectives of this study were (i) to analyze the PPARγ protein and mRNA expression at the follicular level in HT versus controls in correlation with the one of Cav-1; (ii) to study the effects of Th1 cytokines on PPARγ and catalase expression in human thyrocyte primary cultures; and (iii) to study the effects of pioglitazone, a PPARγ agonist, on thyroxisome components (Cav-1, TPO, DUOX) and on catalase, involved in antioxidant defense. Although the global expression of PPARγ in the whole gland of patients with HT was not modified compared with controls, there was great heterogeneity among glands and among follicles within the same thyroid. Besides normal (type 1) follicles, there were around inflammatory zones, hyperactive (type 2) follicles with high PPARγ and Cav-1 expression, and inactive (type 3) follicles which were unable to form thyroxine and did not express PPARγ or Cav-1. In human thyrocytes in primary culture, Th1 cytokines decreased PPARγ and catalase expression; pioglitazone increased Cav-1, TPO, and catalase expression. PPARγ may play a central role in normal thyroid physiology by upregulating Cav-1, essential for the organization of the thyroxisome and extracellular iodination. By upregulating catalase, PPARγ may also contribute to cell homeostasis. The inhibitory effect of Th1 cytokines on PPARγ expression may be considered as a new pathogenetic mechanism for HT, and the use of PPARγ agonists could open a new therapeutic approach.

  1. Down-regulation of Connexin43 expression reveals the involvement of caveolin-1 containing lipid rafts in human U251 glioblastoma cell invasion.

    Science.gov (United States)

    Strale, Pierre-Olivier; Clarhaut, Jonathan; Lamiche, Coralie; Cronier, Laurent; Mesnil, Marc; Defamie, Norah

    2012-11-01

    Glioblastoma cells are characterized by high proliferation and invasive capacities. Tumor development has been associated with a decrease of gap-junctional intercellular communication, but the concrete involvement of gap junction proteins, connexins, remains elusive since they are also suspected to promote cell invasion. In order to better understand how connexins control the glioma cell phenotype, we studied the consequences of inhibiting the intrinsic expression of the major astrocytic connexin, Connexin43, in human U251 glioblastoma cells by the shRNA strategy. The induced down-regulation of Cx43 expression has various effects on the U251 cells such as increased clonogenicity, angiogenesis and decreased adhesion on specific extracellular matrix proteins. We demonstrate that the invasion capacity measured in vitro and ex vivo correlates with Cx43 expression level. For the first time in a cancer cell context, our work demonstrates that Cx43 cofractionates, colocalizes and coimmunoprecipitates with a lipid raft marker, caveolin-1 and that this interaction is inversely correlated to the level of Cx43. This localization of Cx43 in these lipid raft microdomains regulates both homo- and heterocellular gap junctional communications (respectively between U251 cells, or between U251 cells and astrocytes). Moreover, the adhesive and invasive capacities are not dependent, in our model, on Cav-1 expression level. Our results tend to show that heterocellular gap junctional communication between cancer and stroma cells may affect the behavior of the tumor cells. Altogether, our data demonstrate that Cx43 controls the tumor phenotype of glioblastoma U251 cells and in particular, invasion capacity, through its localization in lipid rafts containing Cav-1. Copyright © 2011 Wiley Periodicals, Inc.

  2. Sex-dependent expression of caveolin 1 in response to sex steroid hormones is closely associated with development of obesity in rats.

    Directory of Open Access Journals (Sweden)

    Rajib Mukherjee

    Full Text Available Caveolin-1 (CAV1 is a conserved group of structural membrane proteins that form special cholesterol and sphingolipid-rich compartments, especially in adipocytes. Recently, it has been reported that CAV1 is an important target protein in sex hormone-dependent regulation of various metabolic pathways, particularly in cancer and diabetes. To clarify distinct roles of CAV1 in sex-dependent obesity development, we investigated the effects of high fat diet (HFD and sex steroid hormones on CAV1 expression in adipose tissues of male and female rats. Results of animal experiments revealed that estrogen (17-β-estradiol, E2 and androgen (dihydrotestosterone, DHT had opposite effects on body weight gain as well as on the regulation of CAV1, hormone sensitive lipase (HSL and uncoupling protein 1 (UCP1 in adipose tissues. Furthermore, sex hormone receptors and aromatase were differentially expressed in a sex-dependent manner in response to E2 and DHT treatments. In vivo data were confirmed using 3T3-L1 and HIB1B cell lines, where Cav1 knock down stimulated lipogenesis but suppressed sex hormone receptor signaling proteins. Most importantly, co-immunoprecipitation enabled the identification of previously unrecognized CAV1-interacting mitochondrial or lipid oxidative pathway proteins in adipose tissues. Taken together, current data showed that CAV1 may play important preventive role in the development of obesity, with more prominent effects in females, and proved to be an important target protein for the hormonal regulation of adipose tissue metabolism by manipulating sex hormone receptors and mitochondrial oxidative pathways. Therefore, we can report, for the first time, the molecular mechanism underlying the effects of sex steroid hormones in the sex-dimorphic regulation of CAV1.

  3. The mechanisms of Micrococcus radiodurans radioresistance

    International Nuclear Information System (INIS)

    Samojlenko, I.I.

    1983-01-01

    Modern representations on molecular mechanisms of Micrococcus radiodurans viability under the effect of ionizing radiation have been considered. Factors conditioning a high level of micrococcus cell radiostability have been analyzed: peculiarities of structure of a cell wall, DNA, membranes; excess of genetic information; multiplicity of DNA implantation points to a membrane; high level of antioxidation and antiradical systems. It has been shown that on efficiency of accurate, properly balanced system of DNA repair combined with above Micrococcus radiodurant properties provide a high microorganism radioresistance

  4. Postradiation recovery and radioresistance of seeds

    International Nuclear Information System (INIS)

    Atayan, R.R.; Semerdzhyan, S.P.

    1990-01-01

    Problems on radiobiology of seeds were studied. Irradiation was shown to induce primary injuries in chromosomes sensitive to various modifying factors. Primary injuries can eliminate and form stable physico-chemical injuries as a result of physico-chemical reactions and under concomitant factors. These injuries can be reversible and nonreversible character. Reversible injuries turned out to be potential for they can be repaired at biochemical level. The cells of strong ability to repair postirradiation injuries under various equal conditions reveal a relatively high level of radioresistance. The mechanisms were shown to be basical in the observed differences of radiosensitivity of large and small seeds. 7 refs.; 3 figs

  5. Criteria for estimation of radioresistance of testudo horsfieldi

    Energy Technology Data Exchange (ETDEWEB)

    Turdyev, A.A.; Bogdanova-Berezovskaya, I.G.; Dvornikova, L.I. (AN Uzbekskoj SSR, Tashkent. Inst. Zoologii i Parazitologii)

    A study was made of a phenomenal radioresistance of Testudo horsfieldi. The authors described the features of the postirradiation death at different seasons. A threshold number of the affected systems in the turtles was one order lower than that of mammals. A positive correlaton was found between specific affection of the systems and the degree of their radioresistance.

  6. Caveolin-1 down-regulation is required for Wnt5a-Frizzled 2 signalling in Ha-RasV12 -induced cell transformation.

    Science.gov (United States)

    Lin, Hsiu-Kuan; Lin, Hsi-Hui; Chiou, Yu-Wei; Wu, Ching-Lung; Chiu, Wen-Tai; Tang, Ming-Jer

    2018-05-01

    Caveolin-1 (Cav1) is down-regulated during MK4 (MDCK cells harbouring inducible Ha-Ras V12 gene) transformation by Ha-Ras V12 . Cav1 overexpression abrogates the Ha-Ras V12 -driven transformation of MK4 cells; however, the targeted down-regulation of Cav1 is not sufficient to mimic this transformation. Cav1-silenced cells, including MK4/shCav1 cells and MDCK/shCav1 cells, showed an increased cell area and discontinuous junction-related proteins staining. Cellular and mechanical transformations were completed when MDCK/shCav1 cells were treated with medium conditioned by MK4 cells treated with IPTG (MK4+I-CM) but not with medium conditioned by MK4 cells. Nanoparticle tracking analysis showed that Ha-Ras V12 -inducing MK4 cells increased exosome-like microvesicles release compared with their normal counterparts. The cellular and mechanical transformation activities of MK4+I-CM were abolished after heat treatment and exosome depletion and were copied by exosomes derived from MK4+I-CM (MK4+I-EXs). Wnt5a, a downstream product of Ha-Ras V12 , was markedly secreted by MK4+I-CM and MK4+I-EXs. Suppression of Wnt5a expression and secretion using the porcupine inhibitor C59 or Wnt5a siRNA inhibited the Ha-Ras V12 - and MK4+I-CM-induced transformation of MK4 cells and MDCK/shCav1 cells, respectively. Cav1 down-regulation, either by Ha-Ras V12 or targeted shRNA, increased frizzled-2 (Fzd2) protein levels without affecting its mRNA levels, suggesting a novel role of Cav1 in negatively regulating Fzd2 expression. Additionally, silencing Cav1 facilitated the internalization of MK4+I-EXs in MDCK cells. These data suggest that Cav1-dependent repression of Fzd2 and exosome uptake is potentially relevant to its antitransformation activity, which hinders the activation of Ha-Ras V12 -Wnt5a-Stat3 pathway. Altogether, these results suggest that both decreasing Cav1 and increasing exosomal Wnt5a must be implemented during Ha-Ras V12 -driven cell transformation. © 2018 The Authors

  7. Promotion of human mesenchymal stem cell osteogenesis by PI3-kinase/Akt signaling, and the influence of caveolin-1/cholesterol homeostasis.

    Science.gov (United States)

    Baker, Natasha; Sohn, Jihee; Tuan, Rocky S

    2015-12-01

    Stem cells are considered an important resource for tissue repair and regeneration. Their utilization in regenerative medicine will be aided by mechanistic insight into their responsiveness to external stimuli. It is likely that, similar to all other cells, an initial determinant of stem cell responsiveness to external stimuli is the organization of signaling molecules in cell membrane rafts. The clustering of signaling molecules in these cholesterol-rich membrane microdomains can affect the activity, specificity, cross-talk and amplification of cell signaling. Membrane rafts fall into two broad categories, non-caveolar and caveolar, based on the absence or presence, respectively, of caveolin scaffolding proteins. We have recently demonstrated that caveolin-1 (Cav-1) expression increases during, and knockdown of Cav-1 expression enhances, osteogenic differentiation of human bone marrow derived mesenchymal stem cells (MSCs). The increase in Cav-1 expression observed during osteogenesis is likely a negative feedback mechanism. We hypothesize that focal adhesion signaling pathways such as PI3K/Akt signaling may be negatively regulated by Cav-1 during human MSC osteogenesis. Human bone marrow MSCs were isolated from femoral heads obtained after total hip arthroplasty. MSCs were incubated in standard growth medium alone or induced to osteogenically differentiate by the addition of supplements (β-glycerophosphate, ascorbic acid, dexamethasone, and 1,25-dihydroxyvitamin D3). The activation of and requirement for PI3K/Akt signaling in MSC osteogenesis were assessed by immunoblotting for phosphorylated Akt, and treatment with the PI3K inhibitor LY294002 and Akt siRNA, respectively. The influences of Cav-1 and cholesterol membrane rafts on PI3K/Akt signaling were investigated by treatment with Cav-1 siRNA, methyl-β-cyclodextrin, or cholesterol oxidase, followed by cellular sub-fractionation and/or immunoblotting for phosphorylated Akt. LY294002 and Akt siRNA inhibited MSC

  8. Does the Loss of Stromal Caveolin-1 Remodel the Tumor Microenvironment by Activating Src-Mediated PEAK1 and PI3K Pathways

    Science.gov (United States)

    2017-11-01

    metastatic propensity (Figure 3). By time lapse video microscopy we detected the increase shedding of LO after IL-6 and EGF stimulation (Fig 3C...average 1 hour per response, including the time for reviewing instructions, searching existing data sources, gathering and maintaining the data needed...turn, LO reprogrammed normal prostate fibroblasts stimulate endothelial tube formation in vitro. 15. SUBJECT TERMS PI3K, Prostate Cancer

  9. Studies on radioresistance with HeLa cells

    International Nuclear Information System (INIS)

    Koiwai, Soichiro; Muta, Nobuyoshi

    1980-01-01

    In our previous experiments (15, 16), HeLa cells were successively irradiated with 1 kR of X-rays. After receiving 3, 5, 8, 11, 14, and 17 kR the iradiated HeLa cells showed progressively increasing radioresistance. In the present paper, the results of studies on the variation of the extrapolation number (n), mean lethal dose (D sub(o)), and quasi-threshold dose (D sub(q)) of survival curves for these radioresistant HeLa strains were reported. The values of n of the original and radioresistant strains were all found between 2 and 3, and a change of the n values with an increase in the total dose received by the cell strains was not noticed. On the other hand, the values of D sub(o) of the radioresistant strains progressively increased from 105 R in the original line to 148 R in the 17 kR strain with increasing doses of pre-irradiation. Similarly, the values of D sub(q) had a tendency to increase in the radioresistant strains. Repair of sublethal damage with the original and radioresistant strains was studied and the properties of the radioresistant strains were discussed. (author)

  10. Establishment of clinically relevant radioresistant cell lines and their characteristics

    International Nuclear Information System (INIS)

    Fukumoto, Manabu; Kuwahara, Yoshikazu; Suzuki, Masatoshi

    2014-01-01

    Although radiotherapy is one of the major therapeutic modalities for eradicating malignant tumors, the existence of radioresistant cells remains one of the most critical obstacles. Standard radiotherapy consists of fractionated radiation (FR) of 2-Gy X-rays once a day, 5 days a week, over 60 Gy in total. To understand the characteristics of radioresistant cells and to develop more effective radiotherapy, we have established novel radioresistant cell lines by long-term (> 5 years) exposure to moderate doses of fractionated X-rays. While all the parental human cancer cells ceased, their radioresistant derivatives continue to proliferate with daily exposure to 2-Gy FR for more than 30 days. We have coined those cells as 'clinically relevant radioresistant' (CRR) cells. Transplanted tumors into nude mice were also CRR, indicating that CRR cell lines are powerful tools to improve cancer radiotherapy. We have shown that the suppression of autophagic cell death but not apoptosis was mainly involved in cellular radioresistance. An inhibitor of the mTOR pathway which enhances autophagy was effective to overcome CRR tumors induced in nude mice. But the underlined mechanism was not through the inhibition of autophagy. Guanine nucleotide-binding protein 1 (GBP1) over expression was necessary for maintaining the CRR phenotype, but radioresistant cells were not necessarily cancer stem cells (CSCs). Targeting GBP1 positive cancer cells may be a more efficient method in conquering cancer than targeting CSCs. Slight but significant radioresistance was acquired by 0.5 Gy/12 hrs of long-term FR exposures to parental cells for more than 31 days in accordance with cyclinD1 over expression. This acquired radioresistance (ARR) was stably maintained in the tumor cells even on 31 days after the cessation of 0.5-Gy FR. Present observations give a mechanistic insight for ARR of tumor cells through long-term FR exposure, and provide novel therapeutic targets for radiosensitization

  11. Role of endogenous substances in enhancing radioresistance background

    International Nuclear Information System (INIS)

    Goncharenko, E.N.; Gorskaya, T.G.; Gudz', T.I.; Zolotareva, L.T.; Kovaleva, Z.I.; Peshkova, E.N.

    1978-01-01

    It is shown that in Saccharomyces cerevisiae of ''wild type'' diploid cells (more radioresistant than haploid ones) are characterized by a higher content of endogenous biologically active substances, which possess a radioprotective ability (biogenous amines and SOD), and a lower level of radiosensitizing substances (hydroperoxides of higher unsaturated fatty acids). With Saccharomyces cerevisiae, bearing mutation rad 51, not all the components of the radioresistance background shoW this dependence, which is indicative of the presence of additional factors affecting radioresistance of these cells

  12. Bmi-1 confers adaptive radioresistance to KYSE-150R esophageal carcinoma cells

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Guanyu [Department of General Surgery, Sir Run Run Shaw Hospital, School of Medicine, Zhejiang University, Hangzhou (China); Liu, Luying [Department of Radiotherapy, Zhejiang Cancer Hospital, Hangzhou (China); Sharma, Sherven [David Geffen School of Medicine at UCLA, and the Department of Veterans Affairs, Los Angeles, CA (United States); Liu, Hai; Yang, Weifang; Sun, Xiaonan [Department of Radiotherapy, Sir Run Run Shaw Hospital, School of Medicine, Zhejiang University, Hangzhou (China); Dong, Qinghua, E-mail: dongqinghua@zju.edu.cn [Biomedical Research Center, Sir Run Run Shaw Hospital, School of Medicine, Zhejiang University, Hangzhou (China)

    2012-08-24

    Highlights: Black-Right-Pointing-Pointer Adaptive radioresistant KYSE-150R cells expressed high level of Bmi-1. Black-Right-Pointing-Pointer Bmi-1 depletion sensitized KYSE-150R cells to RT. Black-Right-Pointing-Pointer Bmi-1 depletion increased the generation of ROS in KYSE-150R cells exposed to radiation. Black-Right-Pointing-Pointer Bmi-1 depletion impaired DNA repair capacities in KYSE-150R cells exposed to radiation. -- Abstract: Radiotherapy (RT) is a major modality of cancer treatment. However, tumors often acquire radioresistance, which causes RT to fail. The exact mechanisms by which tumor cells subjected to fractionated irradiation (FIR) develop an adaptive radioresistance are largely unknown. Using the radioresistant KYSE-150R esophageal squamous cell carcinoma (ESCC) model, which was derived from KYSE-150 parental cells using FIR, the role of Bmi-1 in mediating the radioadaptive response of ESCC cells to RT was investigated. The results showed that the level of Bmi-1 expression was significantly higher in KYSE-150R cells than in the KYSE-150 parental cells. Bmi-1 depletion sensitized the KYSE-150R cells to RT mainly through the induction of apoptosis, partly through the induction of senescence. A clonogenic cell survival assay showed that Bmi-1 depletion significantly decreased the radiation survival fraction in KYSE-150R cells. Furthermore, Bmi-1 depletion increased the generation of reactive oxygen species (ROS) and the expression of oxidase genes (Lpo, Noxo1 and Alox15) in KYSE-150R cells exposed to irradiation. DNA repair capacities assessed by {gamma}-H2AX foci formation were also impaired in the Bmi-1 down-regulated KYSE-150R cells. These results suggest that Bmi-1 plays an important role in tumor radioadaptive resistance under FIR and may be a potent molecular target for enhancing the efficacy of fractionated RT.

  13. Duffy antigen receptor for chemokines mediates chemokine endocytosis through a macropinocytosis-like process in endothelial cells.

    Directory of Open Access Journals (Sweden)

    Yani Zhao

    Full Text Available The Duffy antigen receptor for chemokines (DARC shows high affinity binding to multiple inflammatory CC and CXC chemokines and is expressed by erythrocytes and endothelial cells. Recent evidence suggests that endothelial DARC facilitates chemokine transcytosis to promote neutrophil recruitment. However, the mechanism of chemokine endocytosis by DARC remains unclear.We investigated the role of several endocytic pathways in DARC-mediated ligand internalization. Here we report that, although DARC co-localizes with caveolin-1 in endothelial cells, caveolin-1 is dispensable for DARC-mediated (125I-CXCL1 endocytosis as knockdown of caveolin-1 failed to inhibit ligand internalization. (125I-CXCL1 endocytosis by DARC was also independent of clathrin and flotillin-1 but required cholesterol and was, in part, inhibited by silencing Dynamin II expression.(125I-CXCL1 endocytosis was inhibited by amiloride, cytochalasin D, and the PKC inhibitor Gö6976 whereas Platelet Derived Growth Factor (PDGF enhanced ligand internalization through DARC. The majority of DARC-ligand interactions occurred on the endothelial surface, with DARC identified along plasma membrane extensions with the appearance of ruffles, supporting the concept that DARC provides a high affinity scaffolding function for surface retention of chemokines on endothelial cells.These results show DARC-mediated chemokine endocytosis occurs through a macropinocytosis-like process in endothelial cells and caveolin-1 is dispensable for CXCL1 internalization.

  14. A change in radioresistance of barley under chronic irradiation

    International Nuclear Information System (INIS)

    Kal'chenko, V.A.; Shevchenko, V.A.; Fedotov, I.S.

    1981-01-01

    Mutation process and radioresistance of barley growing in an area with increased radiation background (beta radiation doss -0.6 R/day) have been analyzed. Experimental material is given with 250 kindred families where aberration level of chromosomes was analyzed in mitosis and meiosis during 4 years. It is shown that the first generations (M 1 -M 2 ) in experimental material demonstrate an increased level of structural mutations of chromosomes, while the subsequent generations (M 3 -M 4 ) demonstrate the level reduced to control. A higher radioresistance is observed in M 5 plants of chronically irradiated version as compared to nonirradiated version. It is suggested that increase in radioresistance results from the stimulation of repair systems with low doses of chronic irradiation as well as from the selection of a more radioresistant forms out of the population [ru

  15. Characterization of radioresistant variant from U251 human glioblastoma cell line and the role of antioxdant enzymes in its radioresistancy

    International Nuclear Information System (INIS)

    Lee, Hyung Chahn; Park, In Chul; Park, Myung Jin; Woo, Sang Hyeok; Rhee, Chang Hum; Hong, Seok-II

    2004-01-01

    To investigate the radioresistant mechanism in glioblastoma multiforme(GBM), we isolated the radioresistant clone (RRC) from U251 human glioblastoma cell line by exposing to repeated fractions of 3 Gy γ-radiation for six months. RRC had higher radioresistance than the parent cell line as measured by clonogenic survival assay. FACS analysis showed that RRC had a delayed G2 arrest after radiation. Antioxidant enzymes, such as SOD, catalase, glutathione peroxidase (GPX), glutathione reductase (GR), were activated up to 5 folds in RRC after radiation. Erk 1/2 activation was higher in RRC than in the parent cell. Therefore, radioresistancy in RRC might be due to the delayed cell cycle, the coordinated high activation of antioxidant enzyme rather than a single enzyme alone,and higher activation of Erk 1/2

  16. DNA repair mechanism in radioresistant bacteria

    International Nuclear Information System (INIS)

    Kitayama, Shigeru

    1992-01-01

    Many radiation resistant bacteria have been isolated from various sources which are not in high background field. Since Deinococcus radiodurans had been isolated first in 1956, studies on the mechanism for radioresistance were carried out mostly using this bacterium. DNA in this bacterium isn't protected against injury induced by not only ionizing radiation but also ultraviolet light. Therefore, DNA damages induced by various treatments are efficiently and accurately repaired in this cells. Damages in base and/or sugar in DNA are removed by endonucleases which, if not all, are synthesized during postirradiation incubation. Following the endonucleolytic cleavage the strand scissions in DNA are seemed to be rejoined by a process common for the repair of strand scissions induced by such as ionizing radiations. Induce protein(s) is also involved in this rejoining process of strand scissions. DNA repair genes were classified into three phenotypic groups. (1)Genes which are responsible for the endonucleolytic activities. (2) Genes involved in the rejoining of DNA strand scissions. (3) Genes which participate in genetic recombination and repair. Three genes belong to (1) and (2) were cloned onto approximately 1 kbp DNA fragments which base sequences have been determined. (author)

  17. DNA repair mechanism in radioresistant bacteria

    International Nuclear Information System (INIS)

    Kitayama, Shigeru

    1992-01-01

    Many radiation resistant bacteria have been isolated from various sources which are not in high background field. Since Deinococcus radiodurans had been isolated first in 1956, the studies on the mechanism of radioresistance were mostly carried out using this bacterium. DNA in this bacterium isn't protected against injury induced by not only ionizing radiation but also ultraviolet light. Therefore, DNA damages induced by various treatments are efficiently and accurately repaired in this cells. Damages in base and/or sugar in DNA are removed by endonucleases which, if not all, are synthesized during postirradiation incubation. Following the endonucleolytic cleavage the strand scissions in DNA are seemed to be rejoined by a process common for the repair of strand scissions induced by such as ionizing radiations. Induce protein(s) is also involved in this rejoining process of strand scissions. DNA repair genes were classified into three phenotypic groups. (1) Genes which are responsible for the endonucleolytic activities. (2) Genes involved in the rejoining of DNA strand scissions. (3) Genes which participate in genetic recombination and repair. Three genes belong to (1) and (2) were cloned onto approximately 1 kbp DNA fragments which base sequences have been determined. (author)

  18. Putative radioresistant bacterial isolate from sewage water

    International Nuclear Information System (INIS)

    Ang, April; Chua, Patricia; Perez, Kristine; Rey, April; Rivor Kristel; San Pablo, Czarina; Santos, Ernestine

    2001-01-01

    Sewage water was collected from a stagnant body of water in Balara, Quezon City. approximately 150 ml was aseptically transferred into eight Erlenmeyer flasks. Seven flasks were then subjected to different doses of radiation at the 60 Co irradiation facility, PNRI (Philippine Nuclear Research Institute) which are as follows: 0.01 kGy, 0.1 kGy, 0.5 kGy, 1 kGy, 5 kGy, 10 kGy, and 15 kGy. The remaining flask was used as the control. After irradiation, all the different treatments were subjected to colony count at the culture collection laboratory, NSRI. Results showed that the colonies from sewage water treatments irradiated at 0.01 kGy (treatment A), 0.10 kGy (treatment B), and 0.50 kGy (treatment C) exhibited a decreasing trend with colony counts 4.60 x 10 3 CFU/ml, and 1.30 x 10 3 CFU/ml, and 26 CFU/ml, respectively. Contrastingly, at 1 kGy (treatment D), high colony count of 2.95 x 10 3 CFU/ml was observed which is even higher compared to the control (1.02 x 10 3 CFU/ml). Treatment E that was irradiated at 5 kGy manifested low survival rate (25 CFU/ml) indicating the presence of few putative intermediate radioresistant bacteria. Radiation dose treatments higher than 5 kGy (i.e., 10 kGy and 15 kGy) exhibited no bacterial survival. (Author)

  19. Putative radioresistant bacterial isolate from sewage water

    Energy Technology Data Exchange (ETDEWEB)

    Ang, April; Chua, Patricia; Perez, Kristine; Rey, April; Kristel, Rivor; San Pablo, Czarina; Santos, Ernestine

    2001-01-29

    Sewage water was collected from a stagnant body of water in Balara, Quezon City. approximately 150 ml was aseptically transferred into eight Erlenmeyer flasks. Seven flasks were then subjected to different doses of radiation at the {sup 60}Co irradiation facility, PNRI (Philippine Nuclear Research Institute) which are as follows: 0.01 kGy, 0.1 kGy, 0.5 kGy, 1 kGy, 5 kGy, 10 kGy, and 15 kGy. The remaining flask was used as the control. After irradiation, all the different treatments were subjected to colony count at the culture collection laboratory, NSRI. Results showed that the colonies from sewage water treatments irradiated at 0.01 kGy (treatment A), 0.10 kGy (treatment B), and 0.50 kGy (treatment C) exhibited a decreasing trend with colony counts 4.60 x 10{sup 3} CFU/ml, and 1.30 x 10{sup 3} CFU/ml, and 26 CFU/ml, respectively. Contrastingly, at 1 kGy (treatment D), high colony count of 2.95 x 10{sup 3} CFU/ml was observed which is even higher compared to the control (1.02 x 10{sup 3} CFU/ml). Treatment E that was irradiated at 5 kGy manifested low survival rate (25 CFU/ml) indicating the presence of few putative intermediate radioresistant bacteria. Radiation dose treatments higher than 5 kGy (i.e., 10 kGy and 15 kGy) exhibited no bacterial survival. (Author)

  20. Properties of bacterial radioresistance observed in sewage sludge

    Energy Technology Data Exchange (ETDEWEB)

    Watanabe, H; Ito, H; Takehisa, M [Japan Atomic Energy Research Inst., Takasaki, Gunma. Takasaki Radiation Chemistry Research Establishment; Iizuka, H

    1981-09-01

    The changes in radiosensitivities of bacteria in sludge were investigated. The coliforms are more radioresistant in raw sludge than in cake (dewatered sludge). This radioresistance of coliforms was observed not only in raw sludge but also in the cake diluted with water. The radioresistance was independent of the difference of treatment plant, kind of sludge, and season. The oxygen effect on the radioresistance was not observed, but the resistance was changed during storage of sludge. Escherichia coli isolated from sludge was radiosensitive in buffer, but its radiosensitivity was protected by the water-extracts of sludge. On the other hand, radioresistant bacteria were present in total bacteria of sludge irradiated at 2 Mrad. However, the dominant flora in the irradiated sludge consisted of radiosensitive bacteria (mainly Pseudomonas). When a strain of radiosensitive Pseudomonas was irradiated in raw sludge and diluted cake, the radiosensitivity was remarkably protected. From these results, it is suggested that a factor affecting the radiosensitivity of bacteria is present in sludge.

  1. Survivin as a radioresistance factor in pancreatic cancer

    International Nuclear Information System (INIS)

    Asanuma, Koichi; Moriai, Ryosuke; Yajima, Tomomi; Yagihashi, Atsuhito; Yamada, Mikako; Kobayashi, Daisuke; Watanabe, Naoki

    2000-01-01

    We examined whether survivin acts as a constitutive and inducible radioresistance factor in pancreatic cancer cells. Using a quantitative TaqMan reverse transcription-polymerase chain reaction for survivin mRNA in five pancreatic cancer cell lines, we found an inverse relationship between survivin mRNA expression and radiosensitivity. PANC-1 cells, which had the highest survivin mRNA levels, were most resistant to X-irradiation; MIAPaCa-2 cells, which showed the least survivin mRNA expression, were the most sensitive to X-irradiation. Our results suggested that survivin could act as a constitutive radioresistance factor in pancreatic cancer cells. To determine whether radioresistance is enhanced by induction of survivin expression by irradiation, PANC-1 and MIAPaCa-2 cells were subjected to sublethal doses of X-irradiation followed by a lethal dose. Survivin mRNA expression was increased significantly in both PANC-1 and MIAPaCa-2 cell lines by pretreatment with a sublethal dose of X-irradiation, as was cell survival after exposure to the lethal dose. In this system, enzymatic caspase-3 activity was significantly suppressed in cells with acquired resistance. These results suggest that survivin also acts as an inducible radioresistance factor in pancreatic cancer cells. Survivin, then, appears to enhance radioresistance in pancreatic cancer cells; inhibition of survivin mRNA expression may improve the effectiveness of radiotherapy. (author)

  2. Properties of bacterial radioresistance observed in sewage sludge

    International Nuclear Information System (INIS)

    Watanabe, Hiroshi; Ito, Hitoshi; Takehisa, Masaaki; Iizuka, Hiroshi.

    1981-01-01

    The changes in radiosensitivities of bacteria in sludge were investigated. The coliforms are more radioresistant in raw sludge than in cake (dewatered sludge). This radioresistance of coliforms was observed not only in raw sludge but also in the cake diluted with water. The radioresistance was independent of the difference of treatment plant, kind of sludge, and season. The oxygen effect on the radioresistance was not observed, but the resistance was changed during storage of sludge. Escherichia coli isolated from sludge was radiosensitive in buffer, but its radiosensitivity was protected by the water-extracts of sludge. On the other hand, radioresistant bacteria were present in total bacteria of sludge irradiated at 2 Mrad. However, the dominant flora in the irradiated sludge consisted of radiosensitive bacteria (mainly Pseudomonas). When a strain of radiosensitive Pseudomonas was irradiated in raw sludge and diluted cake, the radiosensitivity was remarkably protected. From these results, it is suggested that a factor affecting the radiosensitivity of bacteria is present in sludge. (author)

  3. Establishment of a radioresistant human lung cancer cell subline and its mechanism of radioresistance

    International Nuclear Information System (INIS)

    Zhao Wei; Wang Qiong; Liu Li; Shi Xing; Ding Qian; Wu Gang

    2008-01-01

    Objective: To establish a radioresistant cell subline from a human A549 lung cancer cell line and investigate the mechanism of radioresistance. Methods: Two proposals were applied for the non-small cell lung cancer A549 cells irradiated with X-rays: A group of A549 cell line was irradiated five times, the fractionated dose was 600 cGy, and the other group was exposed 15 times, the fractionated dose was 200 cGy. After the completion of irradiation, two monoclones were obtained from the survival of cells and named the subline A549-S1 and A549-S2. The radiosensitivity and cell cycle distribution of these two clones, together with its parental A549 cells were measured by clone formation assay and flow cytometry. The mRNA and protein levels of Notchl in A549 cell line and the sublines were determined by RT-PCR and Western-blots. Results: Compared with the parental A549 cells, A549-S1 cells showed significant resistance to radiation with D 0 , D q and N values increased, and a broader initial shoulder as well as 1.38-fold increased value of SF 2 . The A549-S1 subline also showed higher percentage of cells in S phase and G 2 /M phase, but lower percentages in G 1 /G 1 phase (P 0 , D q and N values decreased and a curve initial shoulder. The ratio of cells in S and G 0 /G 1 phase ratio was lower than that in parental A549 cells, but that in G 2 /M phase ratio was higher significantly (P<0.05). The expression of Notchl had no marked change compared to A549 cell. Conclusions: The radioresistance of the A549 cell subline is correlated with the irradiation program. The cell subline shows a different cell cycle distribution from their parental line. The cell cycle distribution has a close correlaiton with the expression of Notchl. (authors)

  4. Cancer-associated adipocytes promotes breast tumor radioresistance

    Energy Technology Data Exchange (ETDEWEB)

    Bochet, Ludivine; Meulle, Aline [Universite de Toulouse, UPS, F-31077 Toulouse Cedex (France); CNRS, IPBS (Institut de Pharmacologie et de Biologie Structurale), 205 route de Narbonne, BP 64182, F-31077 Toulouse Cedex (France); Institut National de la Sante et de la Recherche Medicale, INSERM U1048, 1 Avenue du Pr Jean Poulhes, BP 84225, F-31432 Toulouse Cedex (France); Imbert, Sandrine [CNRS, IPBS (Institut de Pharmacologie et de Biologie Structurale), 205 route de Narbonne, BP 64182, F-31077 Toulouse Cedex (France); Salles, Bernard [Universite de Toulouse, UPS, F-31077 Toulouse Cedex (France); CNRS, IPBS (Institut de Pharmacologie et de Biologie Structurale), 205 route de Narbonne, BP 64182, F-31077 Toulouse Cedex (France); Valet, Philippe [Universite de Toulouse, UPS, F-31077 Toulouse Cedex (France); Institut National de la Sante et de la Recherche Medicale, INSERM U1048, 1 Avenue du Pr Jean Poulhes, BP 84225, F-31432 Toulouse Cedex (France); Muller, Catherine, E-mail: muller@ipbs.fr [Universite de Toulouse, UPS, F-31077 Toulouse Cedex (France); CNRS, IPBS (Institut de Pharmacologie et de Biologie Structurale), 205 route de Narbonne, BP 64182, F-31077 Toulouse Cedex (France)

    2011-07-22

    Highlights: {yields} Tumor-surrounding adipocytes contribute to breast cancer progression. {yields} Breast tumor cells previously co-cultivated with mature adipocytes exhibit radioresistance. {yields} Increased in Chk1 phosphorylation is observed in irradiated co-cultivated tumor cells. {yields} IL-6 is over-expressed in tumor cells co-cultivated with adipocytes. {yields} IL-6 exposure confers increased Chk1 phosphorylation and radioresistance in tumor cells. -- Abstract: Mature adipocytes are excellent candidates to influence tumor behavior through heterotypic signaling processes since these cells produce hormones, growth factors, cytokines and other molecules, a heterogeneous group of molecules named adipokines. Using a 2D coculture system, we demonstrate that breast tumor cells previously co-cultivated with mature adipocytes exhibit radioresistance and an earlier and higher increase in the effector kinase Chk1, a phenotype that was associated with decreased cell death as compared to tumor cells grown alone. Interestingly, the adipocytes-induced tumor changes taking place during the coculture time preceding the exposure to IR were sufficient to confer the radioresistant effect. Notorious among the changes brought by adipocytes was the significant increase of IL-6 expression in tumor cells, whose activity may well account for the observed tumor cell protection from IR toxicity. Indeed, our data confirmed the protective role of this cytokine as tumor cells incubated after irradiation with recombinant IL-6 exhibit an increased in Chk1 phosphorylation and a radioresistant phenotype, thus far recapitulating the effects observed in the presence of adipocytes. Our current study sheds light on a new role of tumor-surrounding adipocytes in fostering a radioresistant phenotype in breast tumors, a finding that might have important clinical implications in obese patients that frequently exhibit aggressive diseases.

  5. Radioresistance increase in polymers at high pressures. [. gamma. rays

    Energy Technology Data Exchange (ETDEWEB)

    Milinchuk, V; KIRJUKHIN, V; KLINSHPONT, E

    1977-06-01

    The effect was studied of very high pressures ranging within 100 and 2,700 MPa on the radioresistance of polytetrafluoroethylene, polypropylene and polyethylene in gamma irradiation. For experiments industrial polymers in the shape of blocks, films and fibers were used. It is shown that in easily breakable polymers, such as polytetrafluoroethylene and polypropylene, 1.3 to 2 times less free radicals are formed as a result of gamma irradiation and a pressure of 150 MPa than at normal pressure. The considerably reduced radiation-chemical formation of radicals and the destruction suppression by cross-linking in polymers is the evidence of the polymer radioresistance in irradiation at high pressures.

  6. Cell lysis and superoxide dismutase activities of highly radioresistant bacteria

    International Nuclear Information System (INIS)

    Yoshinaka, Taeko; Yano, Keiji; Yamaguchi, Hikoyuki

    1976-01-01

    The highly radioresistant bacterium, Arthrobacter radiotolerans, has been isolated from the radioactive hot spring of Misasa, and it does not sporulate, it is Gram-positive, and its color is pink to red. This bacterium shows the highest resistance to gamma-ray among Gram-positive resistants, but the lytic enzyme capable of lysing the cells of strong radioresistants and the surface structure of the cells are little known except those about Micrococcus radiodurans. The cells of the M. radiodurans can be lysed by Achramobacter lyticus enzyme, and electron microscopic observation and chemical analysis revealed the mutilayered surface structure of the cells consisting of an inner membrane, a mucopeptide wall layer and a very outer layer. The superoxide dismutase (SOD) activity of aerobic and anaerobic bacteria was studied, and the relatively high SOD activity of the M. radiodurans was found. The SOD function acts against the threat posed by the reactive superoxide radical being generated biologically, photochemically and radiochemically in the presence of molecular oxygen. In this paper, it is reported that the lytic enzyme No.2 obtained from Cytophaga sp., containing N-acetyl-muramyl-L-alanine amidase, peptidase and endopeptidase, and showing broad lytic spectra, was able to lyse the cells of A. radiotolerans and four radioresistant micrococci, and the radioresistant bacteria showed relatively high SOD activity except M. sp. 248. It is well known that superoxide anions are generated by aerobic irradiation, and are toxic to microbial cells. (Kako, I.)

  7. Cell lysis and superoxide dismutase activities of highly radioresistant bacteria

    Energy Technology Data Exchange (ETDEWEB)

    Yoshinaka, T; Yano, K; Yamaguchi, H [Tokyo Univ. (Japan). Faculty of Agriculture

    1976-01-01

    The highly radioresistant bacterium, Arthrobacter radiotolerans, has been isolated from the radioactive hot spring of Misasa, and it does not sporulate, it is Gram-positive, and its color is pink to red. This bacterium shows the highest resistance to gamma-ray among Gram-positive resistants, but the lytic enzyme capable of lysing the cells of strong radioresistants and the surface structure of the cells are little known except those about Micrococcus radiodurans. The cells of the M. radiodurans can be lysed by Achramobacter lyticus enzyme, and electron microscopic observation and chemical analysis revealed the mutilayered surface structure of the cells consisting of an inner membrane, a mucopeptide wall layer and a very outer layer. The superoxide dismutase (SOD) activity of aerobic and anaerobic bacteria was studied, and the relatively high SOD activity of the M. radiodurans was found. The SOD function acts against the threat posed by the reactive superoxide radical being generated biologically, photochemically and radiochemically in the presence of molecular oxygen. In this paper, it is reported that the lytic enzyme No.2 obtained from Cytophaga sp., containing N-acetyl-muramyl-L-alanine amidase, peptidase and endopeptidase, and showing broad lytic spectra, was able to lyse the cells of A. radiotolerans and four radioresistant micrococci, and the radioresistant bacteria showedrelatively high SOD activity except M. sp. 248. It is well known that superoxide anions are generated by aerobic irradiation, and are toxic to microbial cells.

  8. The acquired radioresistance in HeLa cells under conditions mimicking hypoxia was attenuated by a decreased expression of HIF subunit genes induced by RNA interference

    International Nuclear Information System (INIS)

    Doi, Nobutaka; Ogawa, Ryohei; Cui, Zheng-Guo; Morii, Akihiro; Watanabe, Akihiko; Kanayama, Shinji; Yoneda, Yuko; Kondo, Takashi

    2015-01-01

    The cancer cells residing in the hypoxic layer are resistant to radiation and these are ones responsible for cancer recurrence after radiation therapy. One of the reasons why hypoxic cancer cells acquire radioresistance may be attributable to changes in the gene expression profile by the activation of hypoxia inducible factors (HIFs). However, the details underlying this process remain unknown. In this study, we investigated the effects of knockdown of HIF subunit genes to elucidate how HIF subunit genes may be involved in the radioresistance acquired by HeLa cells following exposure to a hypoxia mimic. Interestingly, HIF-1α and HIF-2α seemed mutually complementary for each other when either of them was suppressed. We thus suppressed the expression of both genes simultaneously. To do this, we developed a short hairpin RNA (shRNA) targeting a high homology region between HIF-1α and HIF-2α. It was shown that the expression of the shRNA effectively suppressed the acquisition of radioresistance following the hypoxia mimic. Moreover, it was confirmed that suppression of both subunits resulted in the downregulation of stem cell markers and the suppression of spheroid formation during the hypoxia mimicking-conditions. This shRNA-mediated knockdown method targeting a common region shared by a family of genes may offer a new candidate cancer treatment. - Highlights: • Incubation with CoCl 2 confers radioresistance to HeLa cells. • Both HIF-1α and HIF-2α are involved in the acquisition of radioresistance. • An shRNA to a homology region of HIF-1α and HIF-2α suppressed the radioresistance. • The shRNA decreased cells with stem cell markers and a stem cell phenotype

  9. The acquired radioresistance in HeLa cells under conditions mimicking hypoxia was attenuated by a decreased expression of HIF subunit genes induced by RNA interference

    Energy Technology Data Exchange (ETDEWEB)

    Doi, Nobutaka [Department of Radiological Sciences, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, Toyama 930-0194 (Japan); New Products Research & Development, Gene Engineering Division, NIPPON GENE Co., Ltd. (Japan); Ogawa, Ryohei, E-mail: ogawa@med.u-toyama.ac.jp [Department of Radiological Sciences, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, Toyama 930-0194 (Japan); Cui, Zheng-Guo [Department of Public Health, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama (Japan); Morii, Akihiro; Watanabe, Akihiko [Department of Urology, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama (Japan); Kanayama, Shinji; Yoneda, Yuko [New Products Research & Development, Gene Engineering Division, NIPPON GENE Co., Ltd. (Japan); Kondo, Takashi [Department of Radiological Sciences, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, Toyama 930-0194 (Japan)

    2015-05-01

    The cancer cells residing in the hypoxic layer are resistant to radiation and these are ones responsible for cancer recurrence after radiation therapy. One of the reasons why hypoxic cancer cells acquire radioresistance may be attributable to changes in the gene expression profile by the activation of hypoxia inducible factors (HIFs). However, the details underlying this process remain unknown. In this study, we investigated the effects of knockdown of HIF subunit genes to elucidate how HIF subunit genes may be involved in the radioresistance acquired by HeLa cells following exposure to a hypoxia mimic. Interestingly, HIF-1α and HIF-2α seemed mutually complementary for each other when either of them was suppressed. We thus suppressed the expression of both genes simultaneously. To do this, we developed a short hairpin RNA (shRNA) targeting a high homology region between HIF-1α and HIF-2α. It was shown that the expression of the shRNA effectively suppressed the acquisition of radioresistance following the hypoxia mimic. Moreover, it was confirmed that suppression of both subunits resulted in the downregulation of stem cell markers and the suppression of spheroid formation during the hypoxia mimicking-conditions. This shRNA-mediated knockdown method targeting a common region shared by a family of genes may offer a new candidate cancer treatment. - Highlights: • Incubation with CoCl{sub 2} confers radioresistance to HeLa cells. • Both HIF-1α and HIF-2α are involved in the acquisition of radioresistance. • An shRNA to a homology region of HIF-1α and HIF-2α suppressed the radioresistance. • The shRNA decreased cells with stem cell markers and a stem cell phenotype.

  10. Content of endogenous thiols and radioresistance of gemmating cells of Saccharomyces ellipsoideus and Saccharomyces cerevisiale yeasts

    International Nuclear Information System (INIS)

    Simonyan, N.V.; Avakyan, Ts.M.; Dzhanpoladyan, N.L.; Stepanyan, L.G.

    1983-01-01

    It has been shown that gemmating cells of ''wild type'' yeasts are more radioresistant and contain more endogenous thiols, than resting cells. Gemmating cells of Saccharomyces cerevisial yeasts, carrying the mutation rad 51, as to radioresistance and content of SH groups do not differ from resting cells. The results obtained testify to a connec-- tion between increased radioresistance of the yeast gemmating cells and increased content of endogenous thiols in them

  11. Inhibition of GRP78 abrogates radioresistance in oropharyngeal carcinoma cells after EGFR inhibition by cetuximab.

    Directory of Open Access Journals (Sweden)

    Chaonan Sun

    Full Text Available The EGFR-specific mAb cetuximab is one of the most effective treatments for oropharyngeal carcinoma, while patient responses to EGFR inhibitors given alone are modest. Combination treatment with radiation can improve the efficacy of treatment through increasing radiosensitivity, while resistance to radiation after administration of cetuximab limits its efficiency. Radiation and drugs can damage the endoplasmic reticulum (ER homeostatic state and result in ER stress (ERS, subsequently causing resistance to radiation and drugs. Whether the ERS pathway is involved in radioresistance after administration of cetuximab has not been reported. Herein, we show that cetuximab could increase the radiosensitivity of FaDu cells but not Detroit562 cells. In addition, cetuximab inhibited the radiation-induced activation of the ERS signalling pathway IRE1α/ATF6-GRP78 in FaDu cells, while this effect was absent in Detroit562 cells. Silencing GRP78 increased the radiosensitivity of oropharyngeal carcinoma cells and inhibited radiation-induced DNA double-strand-break (DSB repair and autophagy. More interestingly, silencing GRP78 abrogated resistance to cetuximab and radiation in Detroit562 cells and had a synergistic effect with cetuximab in increasing the radiosensitivity of FaDu cells. Immunohistochemistry showed that overexpression of both GRP78 and EGFR was associated with a poor prognosis in oropharyngeal carcinoma patients (P<0.05. Overall, the results of this study show that radioresistance after EGFR inhibition by cetuximab is mediated by the ERS signalling pathway IRE1α/ATF6-GRP78. This suppression was consequently unable to inhibit radiation-induced DSB repair and autophagy in oropharyngeal carcinoma cells, which conferred resistance to radiotherapy and cetuximab. These results suggest that the cooperative effects of radiotherapy and cetuximab could be further improved by inhibiting GRP78 in non-responsive oropharyngeal carcinoma patients.

  12. Development of radiation countermeasure using novel radioresistant bacteria

    International Nuclear Information System (INIS)

    Kumar, Raj; Singh, Shravan K.; Malhotra, Poonam; Gupta, Ashutosh K.; Singh, Praveen K.; Chhachhia, Neha

    2014-01-01

    Radioresistant bacteria sustain their lives in extreme radiation environment and have capabilities to combat radiation induced oxidative stress. Therefore, factors associated with radioresistancy in bacteria may also provide trans-species radioprotection. To test this hypothesis, present work was initiated at INMAS long back. With this background a novel radioresistant bacterium Bacillus sp. INM-1 isolated and its novel secondary metabolite i.e. Semiquinone Glucoside Derivative (SQGD) carrying radioprotective capabilities was purified. SQGD was evaluated for its free radical scavenging, protein, enzymes, plasmid and biological membranes radioprotection capabilities in vitro. SQGD was also tested for its whole body radioprotective efficacy using oral route of administration. Systemic radioprotection offered by SQGD to gastrointestinal, haematopoietic and male reproductive system was studied. Modulation in endogenous antioxidant enzymes and cytoprotective cytokines expression upon irradiation and SQGD pretreatment was determined. A laboratory process for chemical synthesis of bacterial radioprotective molecule has also been developed (Patent filed No. 2075/DEL/2014). Results of the study demonstrated that SQGD efficiently scavenge free radicals in vitro. SQGD provides excellent protection to structural and functional proteins, plasmid DNA and biomembranes against radiation induced oxidative damage. SQGD was observed to offer ∼ 83% whole body survival to lethally irradiated mice when administered 2h before irradiation by oral route. SQGD was found to ensure significant radioprotection to gastro-intestinal, hematopoietic and male reproductive system of irradiated mice. Protein expression studies revealed that SQGD pretreatment to the irradiated mice significantly increased expression of G-CSF, GM-CSF, MCSF; NFkB, IL-2, IL-12, IL-23, IL-6, PCNA and PARP. In conclusion, present study decisively justified the radioprotective potential of bacterial metabolite SQGD

  13. Down-regulation of survivin by oxaliplatin diminishes radioresistance of head and neck squamous carcinoma cells

    International Nuclear Information System (INIS)

    Khan, Zakir; Khan, Noor; Tiwari, Ram P.; Patro, Ishan K.; Prasad, G.B.K.S.; Bisen, Prakash S.

    2010-01-01

    Background: Oxaliplatin is integrated in treatment strategies against a variety of cancers including radiation protocols. Herein, as a new strategy we tested feasibility and rationale of oxaliplatin in combination with radiation to control proliferation of head and neck squamous cell carcinoma (HNSCC) cells and discussed survivin-related signaling and apoptosis induction. Methods: Cytotoxicity and apoptosis induced by radiation and/or oxaliplatin were examined in relation to survivin status using two HNSCC cell lines viz., Cal27 and NT8e, and one normal 293-cell line. Survivin gene knockdown by siRNA was also tested in relevance to oxaliplatin-mediated radiosensitization effects. Results: Survivin plays a critical role in mediating radiation-resistance in part through suppression of apoptosis via a caspase-dependent mechanism. Oxaliplatin treatment significantly decreased expression of survivin in cancer cells within 24-72 h. Apoptotic cells and caspase-3 activity were increased parallely with decrease in cell viability, if irradiated during this sensitive period. The cytotoxicity of oxaliplatin and radiation combination was greater than additive. Survivin gene knockdown experiments have demonstrated the role of survivin in radiosensitization of cancer cells mediated by oxaliplatin. Conclusions: Higher expression of survivin is a critical factor for radioresistance in HNSCC cell lines. Pre-treatment of cancer cells with oxaliplatin significantly increased the radiosensitivity through induction of apoptosis by potently inhibiting survivin.

  14. Dietary enhancement of intestinal radioresistance during fractionated irradiation

    International Nuclear Information System (INIS)

    Pageau, R.; St-Pierre, C.

    1978-01-01

    Rats fed laboratory chow or elemental diet 3 were given fractions of 240 rads of 60 Co γ radiation abdominally (1200 rads/week) until all animals had died. Changes in appetite, body weight, and mortality were monitored as a function of the cumulative dose received. More radiation was needed in the diet-fed group to achieve both 0 and 100% mortality, a difference of 37% at the mean lethal dose level. Both groups developed similar progressive anorexia but the diet-fed animals lost weight more slowly. Data indicate that basic intestinal radioresistance is enhanced by feeding the elemental diet

  15. Recovery and radio-resistance in mice after external irradiation

    International Nuclear Information System (INIS)

    Le Guillou, S.

    1965-01-01

    The author presents a literature study concerning recovery from external irradiation and an analysis of experimental data (which appear to suggest the idea of a radio-resistance in animals), as well as the hypotheses put forward for explaining this phenomenon. The author then describes an experiment carried out on mice whose LD 50/30 days increased from 1005 to 1380 rads and for which it was shown that an increase occurs in the number of certain anti-bodies circulating after a low dose of γ irradiation. (author) [fr

  16. Isolation and identification of a novel radio-resistant strain

    International Nuclear Information System (INIS)

    Zhang Zhidong; Mao Jun; Wang Wei; Tang Qiyong; Shi Yuhu

    2008-01-01

    A novel radio-resistant strain named RL2 was studied polyphasically, which was isolated from the soils in the Gurban-Tunggut Desert, Xinjiang. The strain is Gam-positive, sphere-shaped and pink pigmented; The DNA (G+C) contents of RL2 is 71.62mo1%; The 16S rDNA genes of RL2 and D. radiodurans type strain DSM20539 shows a high level of similarity (97.2%). According to phenotypic characteristics and phylogenetic analysis, it can be suggested that the strain RL2 has been identified as Deinococcus. sp and it may be a novel species. (authors)

  17. Investigation of ionizing sublethal doses effects on endogenous radioresistance background

    International Nuclear Information System (INIS)

    Kudryashov, Yu.B.; Goncharenko, E.N.; Antonova, S.V.; Akhalaya, M.Ya.; Bajzhumanov, A.A.; Shestakova, S.V.

    1997-01-01

    Sublethal doses of X-radiation (0.5 Gy and 1 Gy) caused the alterations in levels of main components of endogenous radioresistance background in rat tissues. There were demonstrated the decrease of serotonin content in stomach mocosa and spleen, adrenalin, noradrenalin and corticosteroids contents in adrenal glands, nonprotein thiols content in spleen and the increase of lipid peroxide level in serum on the 3-14 days after irradiation. The recovery of the investigated parameters was occurred to the 21 day after exposure. (author)

  18. HDAC4 and HDAC6 sustain DNA double strand break repair and stem-like phenotype by promoting radioresistance in glioblastoma cells.

    Science.gov (United States)

    Marampon, Francesco; Megiorni, Francesca; Camero, Simona; Crescioli, Clara; McDowell, Heather P; Sferra, Roberta; Vetuschi, Antonella; Pompili, Simona; Ventura, Luca; De Felice, Francesca; Tombolini, Vincenzo; Dominici, Carlo; Maggio, Roberto; Festuccia, Claudio; Gravina, Giovanni Luca

    2017-07-01

    The role of histone deacetylase (HDAC) 4 and 6 in glioblastoma (GBM) radioresistance was investigated. We found that tumor samples from 31 GBM patients, who underwent temozolomide and radiotherapy combined treatment, showed HDAC4 and HDAC6 expression in 93.5% and 96.7% of cases, respectively. Retrospective clinical data analysis demonstrated that high-intensity HDAC4 and/or HDAC6 immunostaining was predictive of poor clinical outcome. In vitro experiments revealed that short hairpin RNA-mediated silencing of HDAC4 or HDAC6 radiosensitized U87MG and U251MG GBM cell lines by promoting DNA double-strand break (DSBs) accumulation and by affecting DSBs repair molecular machinery. We found that HDAC6 knock-down predisposes to radiation therapy-induced U251MG apoptosis- and U87MG autophagy-mediated cell death. HDAC4 silencing promoted radiation therapy-induced senescence, independently by the cellular context. Finally, we showed that p53 WT expression contributed to the radiotherapy lethal effects and that HDAC4 or HDAC6 sustained GBM stem-like radioresistant phenotype. Altogether, these observations suggest that HDAC4 and HDAC6 are guardians of irradiation-induced DNA damages and stemness, thus promoting radioresistance, and may represent potential prognostic markers and therapeutic targets in GBM. Copyright © 2017 Elsevier B.V. All rights reserved.

  19. Canonical autophagy does not contribute to cellular radioresistance

    International Nuclear Information System (INIS)

    Schaaf, Marco B.E.; Jutten, Barry; Keulers, Tom G.; Savelkouls, Kim G.M.; Peeters, Hanneke J.M.; Beucken, Twan van den; Schooten, Frederik-Jan van; Godschalk, Roger W.; Vooijs, Marc; Rouschop, Kasper M.A.

    2015-01-01

    Background: (Pre)clinical studies indicate that autophagy inhibition increases response to anti-cancer therapies. Although promising, due to contradicting reports, it remains unclear if radiation therapy changes autophagy activity and if autophagy inhibition changes the cellular intrinsic radiosensitivity. Discrepancies may result from different assays and models through off-target effects and influencing other signaling routes. In this study, we directly compared the effects of genetic and pharmacological inhibition of autophagy after irradiation in human cancer cell lines. Materials and methods: Changes in autophagy activity after ionizing radiation (IR) were assessed by flux analysis in eight cell lines. Clonogenic survival, DNA damage (COMET-assay) and H2AX phosphorylation were assessed after chloroquine or 3-methyladenine pretreatment and after ATG7 or LC3b knockdown. Results: IR failed to induce autophagy and chloroquine failed to change intrinsic radiosensitivity of cells. Interestingly, 3-methyladenine and ATG7- or LC3b-deficiency sensitized cancer cells to irradiation. Surprisingly, the radiosensitizing effect of 3-methyladenine was also observed in ATG7 and LC3b deficient cells and was associated with attenuated γ-H2AX formation and DNA damage repair. Conclusion: Our data demonstrate that the anti-tumor effects of chloroquine are independent of changes in intrinsic radioresistance. Furthermore, ATG7 and LC3b support radioresistance independent of canonical autophagy that involves lysosomal degradation

  20. Radiosensitivity of antibody responses and radioresistant secondary tetanus antitoxin responses

    International Nuclear Information System (INIS)

    Stoner, R.; Terres, G.; Cottier, H.; Hess, M.

    1976-01-01

    Primary tetanus antitoxin responses were increasingly repressed in mice when gamma radiation doses of 100 to 400 rads were delivered by whole-body exposure prior to immunization with fluid tetanus toxoid (FTT). Nearly normal secondary antitoxin responses were obtained in mice exposed to 600 rads of gamma radiation 4 days after secondary antigenic stimulation with FTT. A rapid transition from radiosensitivity of the antibody-forming system on days 1 to 3 was followed by relative radioresistance on day 4 after the booster injection of toxoid. Studies on lymphoid cellular kinetics in popliteal lymph nodes after injection of 3 H--thymidine ( 3 H--TdR) and incorporation of 3 H--L-histidine into circulating antitoxin were carried out. Analysis of tritium radioactivity in antigen--antibody precipitates of serums 2 hr after injection of the labeled amino acid revealed maximum incorporation into antibody around day 7 after the booster in nonirradiated controls and about day 12, i.e., 8 days after irradiation, in experimental mice. The shift from radiosensitivity to relative radioresistance was attributed to a marked peak of plasma-cell proliferation in the medulla of lymph nodes on day 3. Many medullary plasma cells survived and continued to proliferate after exposure to radiation. Germinal centers were destroyed by radiation within 1 day. Since antibody formation continued after exposure to radiation and after the loss of germinal centers, this supports the view that germinal-center cells were involved more in the generation of memory cells than in antibody synthesis

  1. Role of certain cellular composition in radio-resistant fungi

    International Nuclear Information System (INIS)

    Shahin, A.A.M.; Hammad, A.A.I.; Hazaa, M.M.; Swelim, M.A.; Mohamed, Y.A.

    2007-01-01

    Fifty three fungal isolates of genera Curvularia, Alternaria and Fusarium were isolated from different sources included crops, vegetables, fruits in addition to bread, chicken feed soil and air. Five isolates were selected from each genus according to the difference in the morphological characters and its source. The fifteen isolates were exposed to increasing doses of gamma rays from 0.5 to 10.0 I 10 values when irradiated in saline solution were found to be 1.92,1.25, 1.47,0.47,1.31 and 0.70 respectively while their D 10 values were 2.25, 1.56, 1.70, 1.30, 1.83 and 1.23 as the irradiation process was done in their natural sources. The values of total protein, total lipids and total nucleic acids either RNA or DNA were relatively higher in radio-resistant strains than sensitive ones. Amino acids containing sulfur (cysteine, methionine) or double bonds (histidine) and the percentage of unsaturated fatty acids were also higher in resistant strains than the sensitive ones. Exposing the six selected strains to dose level 4 kGy obviously decreased each of total protein, total amino acids and total nucleic acids especially DNA and the values of decreases were found to be higher in sensitive than the resistant strains. Dose level 12.5 kGy was quiet enough to eliminate the radioresistant fungi from the contaminated food whatever the level of contamination is

  2. Evaluation of the role of genetic factors in human radioresistance

    International Nuclear Information System (INIS)

    Telnov, Vitaliy I.; Sotnik, Natalie V.

    2002-01-01

    This study was focused on evaluation of the role of genetic factors in development of chronic radiation sickness (CRS) due to occupational exposure to external γ -rays. This study was based on results of molecular-genetic studies for 985 nuclear workers of the Mayak Production Association. CRS occurrence was related to the genetic haptoglobin (Hp) system among a number of studied genetic markers. Excess risk of CRS was revealed at similar exposure doses for individuals-carriers of Hp 2-2 (1.96) versus lower risks for carriers of Hp 1-1 and 2-1 (0.64). The contribution of genetic factors to CRS development was implemented in a rather narrow dose range, i.e. it was of a relative nature. A scheme of the relationship of affecting factor and differences in genetic radioresistance was presented in terms of deterministic effects. The obtained data did not confirm the idea that A-bomb survivors were more radioresistant, thus being not representative for radiation risk estimation

  3. Impairing the radioresistance of cancer cells by hydrogenated nanodiamonds.

    Science.gov (United States)

    Grall, Romain; Girard, Hugues; Saad, Lina; Petit, Tristan; Gesset, Céline; Combis-Schlumberger, Mathilde; Paget, Vincent; Delic, Jozo; Arnault, Jean-Charles; Chevillard, Sylvie

    2015-08-01

    Hydrogenated nanodiamonds (H-NDs) exhibit a negative electron affinity that confers a high reactivity with oxygen species and a positive charge in aqueous solutions. It allows electron emission from H-NDs following irradiation by photons and in consequence may enhance the effects of radiation on cancer cells. By using three human radioresistant cancer cell lines, we showed a potentialization of cytotoxicity after a co-exposure to H-NDs and irradiation; an event occurring through the induction of DNA damage and reactive oxygen species. This occurred together with a decrease in cell impedance, the activation of G1/S, an unlocking of G2 cell cycle check-points and early low cell death rate. At later stage of exposure, persistent increases in heterochromatinization, large γ-H2AX foci and β-galactosidase activity were detected providing evidence of cells' entrance into senescence. Similar potentialization was observed with neocarzinostatin (NCS), a radiomimetic drug. This original finding underlines a wide clinical potential of H-NDs to intensify radiation effects on radio-resistant cancer cells. Copyright © 2015 The Authors. Published by Elsevier Ltd.. All rights reserved.

  4. Gene expression profile associated with radioresistance and malignancy in melanoma

    International Nuclear Information System (INIS)

    Ibañez, I.L.; Molinari, B.; Notcovich, C.; García, F.M.; Bracalente, C.; Zuccato, C.F.; Durán, H.

    2015-01-01

    The incidence of melanoma has substantially increased over the last decades. Melanomas respond poorly to treatments and no effective therapy exists to inhibit its metastatic spread. The aim of this study was to evaluate the association between radioresistance of melanoma cells and malignancy. A melanoma model developed in our laboratory from A375 human amelanotic melanoma cells was used. It consists in two catalase-overexpressing cell lines with the same genetic background, but with different phenotypes: A375-A7, melanotic and non-invasive and A375-G10, amelanotic and metastatic; and A375-PCDNA3 (transfected with empty plasmid) as control. Radiosensitivity was determined by clonogenic assay after irradiating these cells with a “1”3”7 Cs gamma source. Survival curves were fitted to the linear-quadratic model and surviving fraction at 2 Gy (SF2) was calculated. Results showed that A375-G10 cells were significantly more radioresistant than both A375-A7 and control cells, demonstrated by SF2 and α parameter of survival curves: SF2=0.32±0.03, 0.43±0.16 and 0.89±0.05 and α=0.45±0.05, 0.20±0.05 and 0 for A375-PCDNA3, A375-A7 and A375-G10 respectively. Bioinformatic analysis of whole genome expression microarrays data (Affymetrix) from these cells was performed. A priori defined gene sets associated with cell cycle, apoptosis and MAPK signaling pathway were collected from KEGG (Kyoto Encyclopedia of Genes and Genomes) to evaluate significant differences in gene set expression between cells by GSEA (Gene Set Enrichment Analysis). A375-G10 showed significant decrease in the expression of genes related to DNA damage response (ATM, TP53BP1 and MRE11A) compared to A375-A7 and controls. Moreover, A375-G10 exhibited down-regulated gene sets that are involved in DNA repair, checkpoint and negative regulation of cell cycle and apoptosis. In conclusion, A375-G10 gene expression profile could be involved in radioresistance mechanisms of these cells. Thus, this expression

  5. The role of oxidative stress in EBV lytic reactivation, radioresistance and the potential preventive and therapeutic implications.

    Science.gov (United States)

    Hu, Jianmin; Li, Hongde; Luo, Xiangjian; Li, Yueshuo; Bode, Ann; Cao, Ya

    2017-11-01

    Epstein-Barr virus (EBV) is an important cancer causing virus. Cancer associated with EBV account for approximately 1.5% of all cancers, and represent 1.8% of all cancer deaths worldwide. EBV reactivation plays an important role in the development of EBV-related diseases and is closely related with patients' survival and clinical stages of EBV-related cancers. The therapy regarding to EBV-related cancers is very urgent, especially in endemic areas. Generating oxidative stress is a critical mechanism by which host cells defend against infection by virus. In addition, ROS-mediated oxidative stress plays a significant but paradoxical role acting as a "double-edged sword" to regulate cellular response to radiation, which is the main therapy strategy for EBV-related cancers, especially nasopharyngeal carcinoma. Therefore, in this review we primarily discuss the possible interplay among the oxidative stress, EBV lytic reactivation and radioresistance. Understanding the role of oxidative stress in EBV lytic reactivation and radioresistance will assist in the development of effective strategies for prevention and treatment of EBV-related cancers. © 2017 UICC.

  6. Molecular biological studies on the human radioresistance and drug resistance

    International Nuclear Information System (INIS)

    Kim, Chang Min; Hong, Weon Seon

    1992-04-01

    We irradiated the MKN45 and PC14 cell lines with 500 rads and also established the adriamycin-resistant and cis-platinum resistant cell line. The genomic DNA and total RNA were extracted and subjected to the Southern and Northern analysis using various probes including heat shock protein 70, MDR1, fos, TGFb etc. The mRNA transcript was increased 1 hour after the irradiation and sustained during the 48 hours and returned to the level of pre-irradiation. No significant change was observed with the drug resistant cell lines at the level of gene dosage. We suggest that the marked increase of the hsp70 transcript is very important finding and is believed to be a good candidate for the modulation of the cellular response to irradiation and the radioresistance. (Author)

  7. A role for survivin in radioresistance of pancreatic cancer cells

    International Nuclear Information System (INIS)

    Asanuma, Koichi; Kobayashi, Daisuke; Furuya, Daisuke; Tsuji, Naoki; Yagihashi, Atsuhito; Watanabe, Naoki

    2002-01-01

    Using gene-transduced pancreatic cancer cells, we examined whether survivin expression is directly involved in regulation of radiosensitivity. Ordinarily radiosensitive MIAPaCa-2 cells transduced with wild-type survivin gene (MS cells) proliferated more rapidly than cells transduced with control vector. MS cells were significantly less radiosensitive than control vector-transduced cells. Radiation-induced activity of caspase-3, but not caspase-7, was significantly inhibited in MS cells. On the other hand, transduction of a dominant-negative mutant survivin gene into radioresistant PANC-1 cells augmented radiosensitivity. Further, the radiation-induced increase in caspase-3 activity was enhanced, indicating that survivin function was truly inhibited. These results indicate that survivin expression directly down-regulates radiosensitivity. (author)

  8. Nuclear medicine markers of tumor oxygenation and radioresistance

    International Nuclear Information System (INIS)

    Chapman, J. Donald; Schneider, R.H.; Stobbe, C.C.; Kim, E.; Engelhardt, E.L.; Coia, L.

    1996-01-01

    Purpose/Objective: The objective of this research project was to synthesize, purify, radiolabel and characterize second-generation nuclear medicine markers of tissue oxygenation with properties superior to iodoazomycin arabinoside (IAZA) and to validate the hypoxia-marking activity of optimal compounds by independent measurements of tumor oxygenation and tumor radioresistance. Materials and Methods: Six hypoxic markers of the iodoazomycin nucleoside class with water solubilities greater than IAZA were synthesized by published procedures. The markers were purified, chemically characterized and labeled with Iodine-125 or Iodine-131. Absolute rates of marker ligation to the macromolecules of hypoxic EMT-6 tumor cells in vitro were determined as a function of marker concentration and used to establish relative marker effectiveness. Hypoxic marking activity in tumors was determined from tumor/blood (T/B) and tumor/muscle (T/M) ratios of radiolabelled marker in EMT-6 tumor-bearing C.B17/Icr scid mice. The optimal marker was administered to R3327-H and R3327-AT tumor-bearing Fischer X Copenhagen rats for estimates of tumor oxygenation by T/B and T/M ratios. Oxygen distributions in the same tumors were obtained with the Eppendorf pO 2 Histograph. The radioresistance of individual tumors was determined from in vitro plating efficiencies of cells released from tumors which had been irradiated in vivo with 20 Gy Cs-137 γ-rays. Results: Of the six iodinated azomycin nucleosides investigated, five were novel markers and all had water solubilities higher than IAZA. Iodinated azomycin xylopyranoside (β-D-IAZXP) was selected as the optimal marker of this class since it 1) exhibited the highest absolute rate of ligation to hypoxic tumor cells in vitro, 2) had the fastest plasma clearance rate in tumor-bearing mice and 3) yielded high T/B ratios in both the mouse and rat tumor models employed in this study. Planar nuclear medicine images of (I-131) β-D-IAZXP in tumor-bearing rats

  9. Superoxide dismutase in radioresistant PC-3 human prostate carcinoma cells

    International Nuclear Information System (INIS)

    Prokopovic, J.; Adzic M; Niciforovic, A.; Vucic, V.; Zaric, B.; Radojcic, M. B.

    2006-01-01

    The molecular mechanism of gamma-ionizing radiation (IR) resistance of human prostate cancer cells PC-3 is not known. Since low-LET-IR effects are primarily achieved through generation of reactive oxygen species (ROS), IR-induced expression of ROS-metabolizing antioxidant enzymes, Mn- and CuZn-superoxide dismutase (Mn- and CuZnSOD) and catalase (CAT), and their upstream regulator transcription factor NFκB was followed. Significant elevation of both SODs was found in cells irradiated with 10- and 20 Gy, while CAT and NFκB expression was unchanged. Since, such conditions lead to accumulation of H 2 O 2 , it is concluded that radioresistance of PC-3 cells may emerge from positive feed-forward vicious circle established between H 2 O 2 activation of NFκB and elevated MnSOD activity. (author)

  10. Regulation of radiation-induced protein kinase Cδ activation in radiation-induced apoptosis differs between radiosensitive and radioresistant mouse thymic lymphoma cell lines

    International Nuclear Information System (INIS)

    Nakajima, Tetsuo; Yukawa, Osami; Tsuji, Hideo; Ohyama, Harumi; Wang, Bing; Tatsumi, Kouichi; Hayata, Isamu; Hama-Inaba, Hiroko

    2006-01-01

    Protein kinase Cδ (PKCδ) has an important role in radiation-induced apoptosis. The expression and function of PKCδ in radiation-induced apoptosis were assessed in a radiation-sensitive mouse thymic lymphoma cell line, 3SBH5, and its radioresistant variant, XR223. Rottlerin, a PKCδ-specific inhibitor, completely abolished radiation-induced apoptosis in 3SBH5. Radiation-induced PKCδ activation correlated with the degradation of PKCδ, indicating that PKCδ activation through degradation is involved in radiation-induced apoptosis in radiosensitive 3SBH5. In radioresistant XR223, radiation-induced PKCδ activation was lower than that in radiosensitive 3SBH5. Cytosol PKCδ levels in 3SBH5 decreased markedly after irradiation, while those in XR223 did not. There was no apparent change after irradiation in the membrane fractions of either cell type. In addition, basal cytosol PKCδ levels in XR223 were higher than those in 3SBH5. These results suggest that the radioresistance in XR223 to radiation-induced apoptosis is due to a difference in the regulation of radiation-induced PKCδ activation compared to that of 3SBH5. On the other hand, Atm -/- mouse thymic lymphoma cells were more radioresistant to radiation-induced apoptosis than wild-type mouse thymic lymphoma cells. Irradiated wild-type cells, but not Atm -/- cells, had decreased PKCδ levels, indicating that the Atm protein is involved in radiation-induced apoptosis through the induction of PKCδ degradation. The decreased Atm protein levels induced by treatment with Atm small interfering RNA had no effect on radiation-induced apoptosis in 3SBH5 cells. These results suggest that the regulation of radiation-induced PKCδ activation, which is distinct from the Atm-mediated cascade, determines radiation sensitivity in radiosensitive 3SBH5 cells

  11. Glioblastoma Stem Cells Microenvironment: The Paracrine Roles of the Niche in Drug and Radioresistance

    Directory of Open Access Journals (Sweden)

    Alessia Fidoamore

    2016-01-01

    Full Text Available Among all solid tumors, the high-grade glioma appears to be the most vascularized one. In fact, “microvascular hyperplasia” is a hallmark of GBM. An altered vascular network determines irregular blood flow, so that tumor cells spread rapidly beyond the diffusion distance of oxygen in the tissue, with the consequent formation of hypoxic or anoxic areas, where the bulk of glioblastoma stem cells (GSCs reside. The response to this event is the induction of angiogenesis, a process mediated by hypoxia inducible factors. However, this new capillary network is not efficient in maintaining a proper oxygen supply to the tumor mass, thereby causing an oxygen gradient within the neoplastic zone. This microenvironment helps GSCs to remain in a “quiescent” state preserving their potential to proliferate and differentiate, thus protecting them by the effects of chemo- and radiotherapy. Recent evidences suggest that responses of glioblastoma to standard therapies are determined by the microenvironment of the niche, where the GSCs reside, allowing a variety of mechanisms that contribute to the chemo- and radioresistance, by preserving GSCs. It is, therefore, crucial to investigate the components/factors of the niche in order to formulate new adjuvant therapies rendering more efficiently the gold standard therapies for this neoplasm.

  12. Demonstration and suppression of a radioresistant host-versus-graft reaction

    International Nuclear Information System (INIS)

    Thierfelder, S.; Roessler, R. v.; Ruppelt, W.

    1975-01-01

    The possibilities of suppressing and measuring a radioresistant host-versus-graft reaction are described. According to the authors, the host-versus-graft immune reaction may outlast whole-body irradiation at high doses. (BSC/AK) [de

  13. Comparative radioresistance of chronically irradiated populations of Arabidopsis thaliana (L.) Heynh

    International Nuclear Information System (INIS)

    Dineva, S.B.; Abramov, V.I.; Shevchenko, V.A.

    1994-01-01

    The radioresistance of seeds of populations of Arabidopsis thaliana (L.) Heynh. growing for 5 years in the regions with different levels of radioactive contamination within 30 km zone of Chernobyl NPP was studied. The analysis of comparative radiosensitivity by root test was performed. It has been shown that plants from arabidopsis population growing under chronic irradiation did not gain an increased radioresistance. The data obtained shown that they are more radiosensitive

  14. Modification of γ-irradiation damaging effect on the seeds of radiosensitive and radioresistant plants

    International Nuclear Information System (INIS)

    Kaplan, I.S.; Tikhomirov, F.A.; Khvostova, V.V.; AN SSSR, Novosibirsk. Inst. Tsitologii i Genetiki)

    1975-01-01

    Low and high temperature treatment of seeds during irradiation has shown to result in a decrease of the general deleterious effect of radiation in both relatively radiosensitive (bean) and radioresistant (flax, mustard) species. The protective effect of the treatment is supposed to be due to its influence on short-half-life radicals and this is supportted by experiments with storage of irradiated seeds. The treatment allows to obtain high mutation frequencies in both radiosensitive and radioresistant plants

  15. Increase of corneal epithelium cell radioresistance during regeneration

    International Nuclear Information System (INIS)

    Popova, M.F.; Bulyakova, N.V.; Azarova, V.S.

    1985-01-01

    A comparative study of the radiosensitivity of the normal and regenerating cornea epithelium of C 57 Bl mice was performed on the cellular level, the duration of the cell cycle being taken into account. Criteria of radiation injuries were the number of chromosome aberrations, mitotic index and duration of mitotic block. The anterior part of the head was irradiated singly with 1.75, 3.5 or 7.0 Gy and also repeatedly 3.5 + 3.5 at a 24-hours interval. The corneas were fixed 2, 4, 6, 12, 24, 48, 72 and 96 hours after irradiation. In all cases of irradiated mice the regenerating epithelium showed a shorter mitotic block and significantly lower cytogenetic injury as compared with the controls. Effects of fractionated irradiation were only shown in the regenerating epithelium. The results obtained indicate that regenerating epithelium cells of the cornea are significantly more radioresistant than normal epithelium due to activation of post-radiation recovery, and also, possibly, due to an increase in the content of endogenous radioprotectors. (author)

  16. Radiation-induced-radioresistance: mechanisms and modification radioprotection

    International Nuclear Information System (INIS)

    Bala, Madhu

    2005-01-01

    Full text: The term radiation-induced-radioresistance (RIR) has been chosen to explain a particular class of resistance against lethal doses of radiation, which is transient and is induced by pre-exposure to low doses of radiation. This is a genetically governed phenomenon and is different from adaptation which in one of its several senses, refers to evolutionary transformation into new behavioural patterns. RIR is understood to be an evolutionarily conserved fundamental cellular defense mechanism. Small doses of radiation acting as stress stimuli evoke a concerted action of molecular pathways which help the organism to cope-up with the genotoxic effects of lethal doses of radiation given subsequently. Such molecular pathways are a complex interplay of genetic and biochemical entities and are increasingly becoming the focus of research world over. Most of our information on this subject has been gathered from prokaryotes, simpler eukaryotes, human cells and the epidemiological studies. A number of genes such as GADD 45, CDKN1A, PBP74, DIR1, DDR have been reported by to participate in RIR. However, till date, the mechanism of RIR remain poorly understood. In this deliberation some of our findings on mechanisms of RIR will be presented. Further, modification of RIR by a metabolic modifier, presently under clinical investigations for tumor radiotherapy, will also be presented

  17. Inactivation of carbenicillin by some radioresistant mutant strains

    International Nuclear Information System (INIS)

    Zahiera, T.S.; Mahmoud, M.I.; Bashandy, A.A.

    1990-01-01

    Sensitivity test of five bacterial species to carbenicillin was performed microbiologically. The bacterial species were previously isolated from high level radiation environment. All the studied species could either highly decrease the antibiotic activity or even inactivate it completely. Detailed study of the inactivation of carbenicillin by the radioresistant mutant strains B. Laterosporus, B. firmus and M. roseus was performed, in the present study. Using high performace liquid chromatography technique. The gram-positive m. roseus mutant strain seemed to be the most active mutant in degrading the antibiotic. The left over of the antibiotic attained a value of 9% of the original amount after 14 day incubation of the antibiotic with this mutant strain, while the value of the left over reached 36% and 32% after the same period of incubation with the mutants B. laterosporus and B. firmus respectively. In the case of bacillus species, the degradation of the antibiotic started at the same moment when it was added to the bacterial cultures. This fact may indicate that the inactivation of the studied antibiotic by these bacillus species was due to extracellular enzymes extracted rapidly in the surrounding medium. In the case of M. roseus the inactivation process started later. after the addition of the antibiotic to the mutant culture

  18. Proteomic and transcriptomic profiling of in vitro established radiation resistant oral cancer cells for identification of radioresistance related biomarkers

    International Nuclear Information System (INIS)

    Mohd Yasser; Pawar, Sagar; Teni, Tanuja

    2016-01-01

    Radiotherapy is an integral part of oral cancer treatment, either alone or in combination with surgery. But, during radiotherapy, oral tumours of a subset of patients develop radioresistance that creates major obstruction towards its efficacy. The aim of our study was to establish radioresistant cell lines from different oral subsites using clinically admissible low dose radiation and profile them by proteomic and transcriptomic approaches to identify proteins associated with radioresistance in oral cancer

  19. Isolation of radioresistant microorganisms from a Co/sup 60/ irradiation plant

    International Nuclear Information System (INIS)

    Lezcano, Graciela

    1982-01-01

    The continuos exposition to low doses of gamma irradiation can produce changes in the microflora's radioresistance. In order to obtain information about these possible modifications, the water from the pool used as shielding of the source, as well as the air and the dust in the irradiation chamber of the semi-industrial irradiation plant existing at the Ezeiza Atomic Center were analyzed. The number of microorganisms was determined by filtration techniques and by dilutions. Radioresistance studies of the contaminating microflora were performed. The value of the D/sub 10/ dose was determined in the conditions of highest resistance. A pronounced decrease in the number of microorganisms was observed as a radiation effect in the samples of water and dust, but not in the air samples, this as a consequence of the extractors' action that continually renews the air and the flora in the chamber, thus preventing high-dose exposure. In the air samples no increase of the microorganisms' radioresistance was observed. In the pool water flora, the development of a great radioresistance was observed. A microorganism whose inactivation curve shows a shoulder of 3.2 Mrad was isolated. This high radioresistance could be the result of the continous exposure to low doses during six years. Contrarily, the microorganims of the irradiation chamber's dust did not increase their radioresistance wiht regard to the common contaminants. In the flora of the dust used as a target, two microorganims whose D/sub 10/ were in excess of 400 krad were found; these could be ocassional contaminants. The radioresistant microorganims were isolated and characterized according to Cowan's scheme, the water microorganisms being identified as belonging to the genus Corynebacterium and the earth ones to the genera Micrococcus and Corynebacterium. (author) [es

  20. Reciprocal Regulation of Hypoxia-Inducible Factor 2α and GLI1 Expression Associated With the Radioresistance of Renal Cell Carcinoma

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, Jiancheng [Department of Urology, First Affiliated Hospital of Medical School, Xi' an Jiaotong University, Xi' an (China); Department of Urology, Department of Radiation Oncology, University of Texas Southwestern Medical Center, Dallas, Texas (United States); Wu, Kaijie [Department of Urology, First Affiliated Hospital of Medical School, Xi' an Jiaotong University, Xi' an (China); Gao, Dexuan [Department of Urology, Shandong Provincial Hospital affiliated with Shandong University, Ji' nan (China); Zhu, Guodong; Wu, Dapeng; Wang, Xinyang; Chen, Yule; Du, Yuefeng; Song, Wenbin; Ma, Zhenkun [Department of Urology, First Affiliated Hospital of Medical School, Xi' an Jiaotong University, Xi' an (China); Authement, Craig; Saha, Debabrata [Department of Urology, Department of Radiation Oncology, University of Texas Southwestern Medical Center, Dallas, Texas (United States); Hsieh, Jer-Tsong, E-mail: jt.hsieh@utsouthwestern.edu [Department of Urology, Department of Radiation Oncology, University of Texas Southwestern Medical Center, Dallas, Texas (United States); He, Dalin, E-mail: dalinhe@yahoo.com [Department of Urology, First Affiliated Hospital of Medical School, Xi' an Jiaotong University, Xi' an (China)

    2014-11-15

    Purpose: Renal cell carcinoma (RCC) is often considered a radioresistant tumor, but the molecular mechanism underlying its radioresistance is poorly understood. This study explored the roles of hypoxia-inducible factor 2α (HIF2α) and sonic hedgehog (SHH)-GLI1 signaling in mediating the radioresistance of RCC cells and to unveil the interaction between these 2 signaling pathways. Methods and Materials: The activities of SHH-GLI1 signaling pathway under normoxia and hypoxia in RCC cells were examined by real-time polymerase chain reaction, Western blot, and luciferase reporter assay. The expression of HIF2α and GLI1 in RCC patients was examined by immunohistochemistry, and their correlation was analyzed. Furthermore, RCC cells were treated with HIF2α-specific shRNA (sh-HIF2α), GLI1 inhibitor GANT61, or a combination to determine the effect of ionizing radiation (IR) on RCC cells based on clonogenic assay and double-strand break repair assay. Results: RCC cells exhibited elevated SHH-GLI1 activities under hypoxia, which was mediated by HIF2α. Hypoxia induced GLI1 activation through SMO-independent pathways that could be ablated by PI3K inhibitor or MEK inhibitor. Remarkably, the SHH-GLI1 pathway also upregulated HIF2α expression in normoxia. Apparently, there was a positive correlation between HIF2α and GLI1 expression in RCC patients. The combination of sh-HIF2α and GLI1 inhibitor significantly sensitized RCC cells to IR. Conclusions: Cross-talk between the HIF2α and SHH-GLI1 pathways was demonstrated in RCC. Cotargeting these 2 pathways, significantly sensitizing RCC cells to IR, provides a novel strategy for RCC treatment.

  1. Detection of Quiescent Radioresistant Epithelial Progenitors in the Adult Thymus

    Directory of Open Access Journals (Sweden)

    Maude Dumont-Lagacé

    2017-12-01

    Full Text Available Thymic aging precedes that of other organs and is initiated by the gradual loss of thymic epithelial cells (TECs. Based on in vitro culture and transplantation assays, recent studies have reported on the presence of thymic epithelial progenitor cells (TEPCs in young adult mice. However, the physiological role and properties of TEPC populations reported to date remain unclear. Using an in vivo label-retention assay, we previously identified a population of quiescent but non-senescent TECs. The goals of this study were therefore (i to evaluate the contribution of these quiescent TECs to thymic regeneration following irradiation-induced acute thymic injury and (ii to characterize their phenotypic and molecular profiles using flow cytometry, immunohistology, and transcriptome sequencing. We report that while UEA1+ cells cycle the most in steady state, they are greatly affected by irradiation, leading to cell loss and proliferative arrest following acute thymic involution. On the opposite, the UEA1– subset of quiescent TECs is radioresistant and proliferate in situ following acute thymic involution, thereby contributing to thymic regeneration in 28- to 30-week-old mice. UEA1– quiescent TECs display an undifferentiated phenotype (co-expression of K8 and K5 cytokeratins and express high levels of genes that regulate stem cell activity in different tissues (e.g., Podxl and Ptprz1. In addition, two features suggest that UEA1– quiescent TECs occupy discrete stromal niches: (i their preferential location in clusters adjacent to the cortico-medullary junction and (ii their high expression of genes involved in cross talk with mesenchymal cells. The ability of UEA1– quiescent TECs to participate to TEC regeneration qualifies them as in vivo progenitor cells particularly relevant in the context of regeneration following acute thymic injury.

  2. Mediatization

    DEFF Research Database (Denmark)

    Hjarvard, Stig

    2017-01-01

    Mediatization research shares media effects studies' ambition of answering the difficult questions with regard to whether and how media matter and influence contemporary culture and society. The two approaches nevertheless differ fundamentally in that mediatization research seeks answers...... to these general questions by distinguishing between two concepts: mediation and mediatization. The media effects tradition generally considers the effects of the media to be a result of individuals being exposed to media content, i.e. effects are seen as an outcome of mediated communication. Mediatization...... research is concerned with long-term structural changes involving media, culture, and society, i.e. the influences of the media are understood in relation to how media are implicated in social and cultural changes and how these processes come to create new conditions for human communication and interaction...

  3. Stable radioresistance in ataxia-telangiectasia cells containing DNA from normal human cells

    International Nuclear Information System (INIS)

    Kapp, L.N.; Painter, R.B.

    1989-01-01

    SV40-transformed ataxia-telangiectasia (AT) cells were transfected with a cosmid containing a normal human DNA library and selectable marker, the neo gene, which endows successfully transformed mammalian cells with resistance to the antibiotic G418. Cells from this line were irradiated with 50 Gy of X-rays and fused with non-transfected AT cells. Among the G418-resistant colonies recovered was one stably resistant to radiation. Resistance to ionizing radiation of both primary transfectant line and its fusion derivative was intermediate between that of AT cells and normal cells, as assayed by colony-forming ability and measurement of radiation-induced G 2 chromatic aberrations; both cell lines retained AT-like radioresistant DNA synthesis. Results suggest that, because radioresistance in transfected cells was not as great as in normal human cells, two hallmarks of AT, radiosensitivity and radioresistant DNA synthesis, may still be the result of a single defective AT gene. (author)

  4. Expressed sequence tags of differential genes in the radioresistant mice and their parental mice

    International Nuclear Information System (INIS)

    Wang Qin; Yue Jingyin; Li Jin; Song Li; Liu Qiang; Mu Chuanjie; Wu Hongying

    2009-01-01

    Objective: To explore radioresistance correlative genes in IRM-2 inbred mouse. Methods: The total RNA was extracted from spleen cells of IRM-2 and their parent 615 and ICR/JCL mouse. The mRNA differential display technique was used to analyze gene expression differences. Each differential bands were amplified by PCR, cloned and sequenced. Results: There were 75 differential expression bands appearing in IRM-2 mouse but not in 615 and ICR/JCL mouse. Fifty-two pieces of cDNA sequences were got by sequencing. Twenty-one expressed sequence tags (EST) that were not the same as known mice genes were found and registered by comparing with GenBank database. Conclusion: Twenty-one EST denote that radioresistance correlative genes may be in IRM-2 mouse, which have laid a foundation for isolating and identifying radioresistance correlative genes in further study. (authors)

  5. No impact on P-gp level in radio-resistant Mcf-7 cells

    International Nuclear Information System (INIS)

    Madhu, L.N.; Rao, Shama; Sarojini, B.K.

    2016-01-01

    Cancer has become the leading cause of human death worldwide. One possible cause for therapeutic failure is that residual tumor cells are reminiscent of stem cells, which ultimately give rise to secondary tumors or distant metastasis. The property of resistance to radiation therapy or chemotherapy might be the major clinical criterion to characterize 'cancer stem cells (CSCs)'. In the process of radiotherapy, the radiosensitive cancer will become a radioresistant one. Such radio-resistance cells might also show the characters of multi drug resistance (MRD) properties which may affect the chemotherapy process. The present study was carried out to know the expression level of P-gp, a MRD protein in radioresistance breast cancer cells. The study conducted by exposing the MCF-7 cells to 4Gy of gamma radiation

  6. Impact of anthropogenic forest contamination on radioresistance of woody plant seed

    International Nuclear Information System (INIS)

    Yushkov, P.I.

    2004-01-01

    Radioresistance of seeds of bay willow (Salix pentandra L.) and great sallow willow (Salix caprea L.) from forests chronically affected and non-affected by acidic (SO 2 , NO x , HF, etc.) industries has been studied and compared. Bay willow seeds of 6 harvests showed no difference in radioresistance. However, seeds of both species manifested strong synchronous variability in resistance to preplant exposure. Also, no influence was observed of mother plant gas content on great sallow willow seeds of different harvests. Data obtained confirm similar results of previous studies conducted by the author (1987) to identify the impact of plant gas content on radioresistance of seeds and seedlings of pine (Pinus sylvestris L.) and birch (Betula verrucosa Erh.). (author)

  7. Heavy metals-bioremediation by highly radioresistant Deinococcus radiodurans biofilm prospective use in nuclear reactor decontamination

    International Nuclear Information System (INIS)

    Shukla, Sudhir K.; Subba Rao, T.

    2015-01-01

    Over the past few decades, rapid growth of chemical industries have enhanced the heavy metal contamination in water, thereby raising environmental concerns. In the nuclear power industry, decontamination procedure also generates radioactive heavy metal containing wastes. Radio-resistant Deinococcus radiodurans R1 is reported to be a potential candidate for the treatment of low active waste material. To use any bacterium for bioremediation purpose, knowledge about its biofilm production characteristics is a prerequisite. This is because biofilm-mediated bioremediation processes are more efficient as compared to processes mediated by their planktonic counterparts. However, so far there are no reports on the biofilm producing capability of D. radiodurans. We observed that tagging of D. radiodurans by a plasmid harbouring gfp and kan R conferred significant biofilm producing property to the bacterium. Chemical analysis of biofilm matrix components produced by D. radiodurans showed that the matrix consists primarily of proteins and carbohydrates with small amount of extracellular DNA (eDNA). Further, we studied the effect of Ca 2+ on D. radiodurans biofilm formation and it was observed that D. radiodurans biofilm formation was enhanced at higher concentrations of Ca 2+ . We investigated the capability of D. radiodurans biofilm to remove the heavy metals Co and Ni from synthetic waste streams. Results showed that Ca 2+ enhanced the bioremediation of both heavy metals (Co, Ni) by D. radiodurans biofilms in a highly significant manner. In the presence of 50 mM Ca 2+ 35% Co removal and 25% Ni removal was observed, when compared to biofilm grown in the absence of Ca 2+ , which showed mere 7% Co and 3% Ni removal, respectively. The results showed that the presence of Ca 2+ significantly enhanced exopolysaccharide and eDNA (both negatively charged) production in the biofilm matrix. This indicated adsorption could be the major mechanism behind enhanced biofilm mediated removal

  8. Radioresistance of human glioma spheroids and expression of HSP70, p53 and EGFr

    International Nuclear Information System (INIS)

    Fedrigo, Carlos A; Rocha, Adriana B da; Grivicich, Ivana; Schunemann, Daniel P; Chemale, Ivan M; Santos, Daiane dos; Jacovas, Thais; Boschetti, Patryck S; Jotz, Geraldo P; Filho, Aroldo Braga

    2011-01-01

    Radiation therapy is routinely prescribed for high-grade malignant gliomas. However, the efficacy of this therapeutic modality is often limited by the occurrence of radioresistance, reflected as a diminished susceptibility of the irradiated cells to undergo cell death. Thus, cells have evolved an elegant system in response to ionizing radiation induced DNA damage, where p53, Hsp70 and/or EGFr may play an important role in the process. In the present study, we investigated whether the content of p53, Hsp70 and EGFr are associated to glioblastoma (GBM) cell radioresistance. Spheroids from U-87MG and MO59J cell lines as well as spheroids derived from primary culture of tumor tissue of one GBM patient (UGBM1) were irradiated (5, 10 and 20 Gy), their relative radioresistance were established and the p53, Hsp70 and EGFr contents were immunohistochemically determined. Moreover, we investigated whether EGFr-phospho-Akt and EGFr-MEK-ERK pathways can induce GBM radioresistance using inhibitors of activation of ERK (PD098059) and Akt (wortmannin). At 5 Gy irradiation UGBM1 and U-87MG spheroids showed growth inhibition whereas the MO59J spheroid was relatively radioresistant. Overall, no significant changes in p53 and Hsp70 expression were found following 5 Gy irradiation treatment in all spheroids studied. The only difference observed in Hsp70 content was the periphery distribution in MO59J spheroids. However, 5 Gy treatment induced a significant increase on the EGFr levels in MO59J spheroids. Furthermore, treatment with inhibitors of activation of ERK (PD098059) and Akt (wortmannin) leads to radiosensitization of MO59J spheroids. These results indicate that the PI3K-Akt and MEK-ERK pathways triggered by EGFr confer GBM radioresistance

  9. Isolation and identification of radioprotective compound (s) from radioresistant culture of Fusarium Moniliforme

    International Nuclear Information System (INIS)

    Adam, Y.M.; Attaby, H.S.H.

    2001-01-01

    Mat extract and filtrate of the radio-resistant strain Fusarium Moniliforme have been prepared and tested for their radioprotective action on the radiosensitive strain Trichoderma Viride. Both extracts gave T. Viride a protective effect against gamma radiation. Analysis of mat extracts and filtrates of both fungi, the radioresistant F. Moniliforme and the radiosensitive T. Viride revealed a pronounced differences in amino acids quantities in addition to the presence of gibberelic acid (GA 3 ) in the filtrate of F. Moniliforme only. Generally, the radioresistant fungus F. Moniliforme was able to accumulate ten amino acids in large quantity than the radiosensitive one. These amino acids comprised, cystine, glutamic acid, serine, methionine, histidine, proline, arginine, alanine, glycine and therionine. The amino acid pool of both fungi was poor in filtrate than in the mat extract. Analysis of filtration of F. Moniliforme was characterized by high content of gibberellic acid, whereas, only traces were detected in mat extract. No gibberellic acid was detected in both mat extract and filtrate of T. Viride. The results of this investigation, revealed also that both amino acids and gibberellic acid were subjected to pronounced disturbances following irradiation compared with the control. A close correlation between the induced radioresistance of T. Viride and the amounts of amino acids and G A, added to its culture medium was observed, suggesting their participation in radioprotection

  10. Radioresistance related genes screened by protein-protein interaction network analysis in nasopharyngeal carcinoma

    International Nuclear Information System (INIS)

    Zhu Xiaodong; Guo Ya; Qu Song; Li Ling; Huang Shiting; Li Danrong; Zhang Wei

    2012-01-01

    Objective: To discover radioresistance associated molecular biomarkers and its mechanism in nasopharyngeal carcinoma by protein-protein interaction network analysis. Methods: Whole genome expression microarray was applied to screen out differentially expressed genes in two cell lines CNE-2R and CNE-2 with different radiosensitivity. Four differentially expressed genes were randomly selected for further verification by the semi-quantitative RT-PCR analysis with self-designed primers. The common differentially expressed genes from two experiments were analyzed with the SNOW online database in order to find out the central node related to the biomarkers of nasopharyngeal carcinoma radioresistance. The expression of STAT1 in CNE-2R and CNE-2 cells was measured by Western blot. Results: Compared with CNE-2 cells, 374 genes in CNE-2R cells were differentially expressed while 197 genes showed significant differences. Four randomly selected differentially expressed genes were verified by RT-PCR and had same change trend in consistent with the results of chip assay. Analysis with the SNOW database demonstrated that those 197 genes could form a complicated interaction network where STAT1 and JUN might be two key nodes. Indeed, the STAT1-α expression in CNE-2R was higher than that in CNE-2 (t=4.96, P<0.05). Conclusions: The key nodes of STAT1 and JUN may be the molecular biomarkers leading to radioresistance in nasopharyngeal carcinoma, and STAT1-α might have close relationship with radioresistance. (authors)

  11. DNA repair and cytokines: TGF-beta, IL-6, and thrombopoietin as different biomarkers of radioresistance

    Directory of Open Access Journals (Sweden)

    Francesca Bianca Aiello

    2016-07-01

    Full Text Available Double strand breaks (DSBs induced by radiotherapy are highly cytotoxic lesions, leading to chromosomal aberrations and cell death. ATM-dependent DNA-damage response, non-homologous end joining, and homologous recombination pathways coordinately contribute to repairing DSBs in higher eukaryotes. It is known that the expression of DSB repair genes is increased in tumors which is one of the main reasons for radioresistance. The inhibition of DSB repair pathways may be useful to increase tumor cell radiosensitivity and may target stem cell-like cancer cells, known to be the most radioresistant tumor components. Commonly overexpressed in neoplastic cells, cytokines confer radioresistance by promoting proliferation, survival, invasion, and angiogenesis. Unfortunately, tumor irradiation increases the expression of various cytokines displaying these effects, including transforming growth factor-beta and interlukin-6. Recently the capabilities of these cytokines to support DNA repair pathways and the ATM-dependent DNA response have been demonstrated. Thrombopoietin, essential for megakaryopoiesis and very important for hematopoietic stem cell homeostasis, has also been found to promote DNA repair in a highly selective manner. These findings reveal a novel mechanism underlying cytokine-related radioresistance, which may be clinically relevant. Therapies targeting specific cytokines may be used to improve radiosensitivity. Specific inhibitors may be chosen in consideration of different tumor microenvironments. Thrombopoietin may be useful in fending off irradiation-induced loss of hematopoietic stem cells.

  12. GPR56/ADGRG1 Inhibits Mesenchymal Differentiation and Radioresistance in Glioblastoma

    NARCIS (Netherlands)

    Moreno, Marta; Pedrosa, Leire; Pare, Laia; Pineda, Estela; Bejarano, Leire; Martinez, Josefina; Balasubramaniyan, Veerakumar; Ezhilarasan, Ravesanker; Kallarackal, Naveen; Kim, Sung-Hak; Wang, Jia; Audia, Alessandra; Conroy, Siobhan; Marin, Mercedes; Ribalta, Teresa; Pujol, Teresa; Herreros, Antoni; Tortosa, Avelina; Mira, Helena; Alonso, Marta M.; Gomez-Manzano, Candelaria; Graus, Francesc; Sulman, Erik P.; Piao, Xianhua; Nakano, Ichiro; Prat, Aleix; Bhat, Krishna P.; de la Iglesia, Nuria

    2017-01-01

    A mesenchymal transition occurs both during the natural evolution of glioblastoma (GBM) and in response to therapy. Here, we report that the adhesion G-protein-coupled receptor, GPR56/ADGRG1, inhibits GBM mesenchymal differentiation and radioresistance. GPR56 is enriched in proneural and

  13. CD133-expressing thyroid cancer cells are undifferentiated, radioresistant and survive radioiodide therapy

    International Nuclear Information System (INIS)

    Ke, Chien-Chih; Liu, Ren-Shyan; Yang, An-Hang; Liu, Ching-Sheng; Chi, Chin-Wen; Tseng, Ling-Ming; Tsai, Yi-Fan; Ho, Jennifer H.; Lee, Chen-Hsen; Lee, Oscar K.

    2013-01-01

    131 I therapy is regularly used following surgery as a part of thyroid cancer management. Despite an overall relatively good prognosis, recurrent or metastatic thyroid cancer is not rare. CD133-expressing cells have been shown to mark thyroid cancer stem cells that possess the characteristics of stem cells and have the ability to initiate tumours. However, no studies have addressed the influence of CD133-expressing cells on radioiodide therapy of the thyroid cancer. The aim of this study was to investigate whether CD133 + cells contribute to the radioresistance of thyroid cancer and thus potentiate future recurrence and metastasis. Thyroid cancer cell lines were analysed for CD133 expression, radiosensitivity and gene expression. The anaplastic thyroid cancer cell line ARO showed a higher percentage of CD133 + cells and higher radioresistance. After γ-irradiation of the cells, the CD133 + population was enriched due to the higher apoptotic rate of CD133 - cells. In vivo 131 I treatment of ARO tumour resulted in an elevated expression of CD133, Oct4, Nanog, Lin28 and Glut1 genes. After isolation, CD133 + cells exhibited higher radioresistance and higher expression of Oct4, Nanog, Sox2, Lin28 and Glut1 in the cell line or primarily cultured papillary thyroid cancer cells, and lower expression of various thyroid-specific genes, namely NIS, Tg, TPO, TSHR, TTF1 and Pax8. This study demonstrates the existence of CD133-expressing thyroid cancer cells which show a higher radioresistance and are in an undifferentiated status. These cells possess a greater potential to survive radiotherapy and may contribute to the recurrence of thyroid cancer. A future therapeutic approach for radioresistant thyroid cancer may focus on the selective eradication of CD133 + cells. (orig.)

  14. Evidence and analysis of radioresistance induced by protracted gamma irradiation of Chlorella pyrenoidosa chick, green unicellular alga

    International Nuclear Information System (INIS)

    Santier-Riviere, S.

    1984-06-01

    Chlorella cells, unicellular green algae, are a suitable living material to study radiosensitivity of eucaryotic cells after acute or protracted gamma irradiations. Cell survival and survival curves are taken as end-points. Methods of irradiation were defined taking in account interferences of the different factors which can intervene during the experimentation. Survival curves after protracted irradiation of Chlorella cell cultures in plateau-phase have a shape that can be explained by radioresistance. The population of surviving cells becomes radioresistant in front of protracted and acute irradiations, acute irradiation allowing us to analyze radioresistance. Radioresistance increases with the total dose of protracted irradiation. The decrease of radiosensitivity with aging of cells is not able to explain the phenomenon. It is not due to selection of radioresistance cells by protracted irradiation. All the cells get radioresistance. Radioresistance decreases with the time when protracted irradiation is suppressed. It is not found in offspring. It is not a mutation but perhaps the effect of a stimulation of repair processes, but not potentially lethal damage repair [fr

  15. Activation of mitochondrial promoter PH-binding protein in a radio-resistant Chinese hamster cell strain associated with Bcl-2

    International Nuclear Information System (INIS)

    Roychoudhury, Paromita; Ghosh, Utpal; Bhattacharyya, Nitai P.; Chaudhuri, Keya

    2006-01-01

    The cellular response to ionizing radiation is mediated by a complex interaction of number of proteins involving different pathways. Previously, we have shown that up regulation of mitochondrial genes ND1, ND4, and COX1 transcribed from the heavy strand promoter (P H ) has been increased in a radio-resistant cell strain designated as M5 in comparison with the parental Chinese hamster V79 cells. These genes are also up regulated in Chinese hamster V79 cells VB13 that express exogenous human Bcl2. In the present study, the expression of the gene ND6 that is expressed from the light strand promoter (P L ) was found to be similar in both the cell lines, as determined by RT-PCR. To test the possibility that this differential expression of mitochondrial genes under these two promoters was mediated by differences in proteins' affinity to interact with these promoters, we have carried out electrophoretic mobility shift assay (EMSA) using mitochondrial cell extracts from these two cell lines. Our result of these experiments revealed that two different proteins formed complex with the synthetic promoters and higher amount of protein from M5 cell extracts interacted with the P H promoter in comparison to that observed with cell extracts from Chinese hamster V79 cells. The promoter-specific differential binding of proteins was also observed in VB13. These results showed that differential mitochondrial gene expression observed earlier in the radio-resistant M5 cells was due to enhanced interaction proteins with the promoters P H and mediated by the expression of Bcl2

  16. Natural cytotoxicity in immunodeficiency diseases: preservation of natural killer activity and the in vivo appearance of radioresistant killing

    International Nuclear Information System (INIS)

    Pierce, G.F.; Polmar, S.H.; Schacter, B.Z.; Brovall, C.; Hornick, D.L.; Sorensen, R.U.

    1986-01-01

    We studied spontaneous natural killer (NK) cell activity and radiation-resistant NK mediated cytotoxicity in four patients with clinically documented severe combined immune deficiency disease (SCID), and in one subject each with intestinal lymphangiectasia and cartilage-hair hypoplasia. We observed the preservation of spontaneous NK activity in all patients despite the presence of profound B- and T-lymphocytopenia and clinical immunodeficiency. NK activity was associated with relatively normal circulating numbers of OKM1+ lymphocytes, a population known to contain NK effectors. Spontaneous NK activity resistant to 3000 rad was increased in all patients, indicating the presence of activated natural killer cells in vivo. The concept of a chronically activated immune system in these patients was further supported by the presence of increased Ia positive T cells in all subjects tested, suggesting that radioresistant NK activity may be a useful parameter to measure when assessing in vivo immune activation. Our data, as well as that of others, supports the hypothesis that at least one population of NK cells is a distinct lineage arising at the differentiation level of myeloid and lymphoid stem cells in the bone marrow

  17. Decursin reduce radio-resistance of hypoxic regions under the proton beam therapy by induced HIF-1α degradation

    International Nuclear Information System (INIS)

    Jung, Myung Hwan; Kim, Kye Ryung

    2013-01-01

    Protons induce cancer-cell apoptosis in vitro and block blood vessel formation in vivo through the generation of reactive oxygen species (ROS). The fact that proton severely inhibits blood vessel development in zebrafish embryos suggests a higher sensitivity of vascular endothelial cells to proton beam. Decursin, a coumarin compound, was originally isolated from Angelica gigas Nakai (Dang Gui). A. gigas root has been traditionally used in Korean folk medicine for the treatment of anemia and other common diseases. In previous reports, decursin was reported to exhibit anti-tumor activity against various cancer cells and to inhibit the activities of the androgen and androgen-receptor (AR) signaling pathway in prostate cancer, induction of cell cycle arrest and apoptosis in various cancer cells, such as prostate, breast, bladder, and colon cancer cells. Decursin also inhibits VEGF-induced angiogenesis through the suppression of the VEGFR-2-signaling pathway. However, the mechanism of decursin mediates change of HIF-1α activities is not clear. In this research, we identified regulations of the HIF-1α and the anti-angiogenesis effects of decursin in proton-beam-irradiated human lung cancer, prostate cancer and Hepatic cancer cells. We investigated the underlying mechanisms of positive effects of protonbeam-induced anti-angiogenesis. Our data indicate that the groups co-treated with decursin and a proton-beam had significant reduced HIF-1α activity compared with the groups treated with only a proton beam under the hypoxic condition caused by DFX(desferrioxamine). Decursin was found to induced HIF-1α degradation. Therefore, we suggest that decursin may be a potential candidate for use as a sensitizer for proton-beaminduced cell apoptosis. Here we have shown that decursin successfully reduced HIF-1α stability under hypoxic condition by induced desferrioxamine. We showed novel candidates for anti-angiogenic compound, decursin, leading to complete inhibition of radio-resistance

  18. Decursin reduce radio-resistance of hypoxic regions under the proton beam therapy by induced HIF-1α degradation

    Energy Technology Data Exchange (ETDEWEB)

    Jung, Myung Hwan; Kim, Kye Ryung [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2013-10-15

    Protons induce cancer-cell apoptosis in vitro and block blood vessel formation in vivo through the generation of reactive oxygen species (ROS). The fact that proton severely inhibits blood vessel development in zebrafish embryos suggests a higher sensitivity of vascular endothelial cells to proton beam. Decursin, a coumarin compound, was originally isolated from Angelica gigas Nakai (Dang Gui). A. gigas root has been traditionally used in Korean folk medicine for the treatment of anemia and other common diseases. In previous reports, decursin was reported to exhibit anti-tumor activity against various cancer cells and to inhibit the activities of the androgen and androgen-receptor (AR) signaling pathway in prostate cancer, induction of cell cycle arrest and apoptosis in various cancer cells, such as prostate, breast, bladder, and colon cancer cells. Decursin also inhibits VEGF-induced angiogenesis through the suppression of the VEGFR-2-signaling pathway. However, the mechanism of decursin mediates change of HIF-1α activities is not clear. In this research, we identified regulations of the HIF-1α and the anti-angiogenesis effects of decursin in proton-beam-irradiated human lung cancer, prostate cancer and Hepatic cancer cells. We investigated the underlying mechanisms of positive effects of protonbeam-induced anti-angiogenesis. Our data indicate that the groups co-treated with decursin and a proton-beam had significant reduced HIF-1α activity compared with the groups treated with only a proton beam under the hypoxic condition caused by DFX(desferrioxamine). Decursin was found to induced HIF-1α degradation. Therefore, we suggest that decursin may be a potential candidate for use as a sensitizer for proton-beaminduced cell apoptosis. Here we have shown that decursin successfully reduced HIF-1α stability under hypoxic condition by induced desferrioxamine. We showed novel candidates for anti-angiogenic compound, decursin, leading to complete inhibition of radio-resistance

  19. Prognostic factors for outcomes after whole-brain irradiation of brain metastases from relatively radioresistant tumors: a retrospective analysis

    NARCIS (Netherlands)

    Meyners, T.; Heisterkamp, C.; Kueter, J.D.; Veninga, T.; Stalpers, L.J.A.; Schild, S.E.; Rades, D.

    2010-01-01

    Background: This study investigated potential prognostic factors in patients treated with whole-brain irradiation (WBI) alone for brain metastases from relatively radioresistant tumors such as malignant melanoma, renal cell carcinoma, and colorectal cancer. Additionally, a potential benefit from

  20. Prognostic factors for outcomes after whole-brain irradiation of brain metastases from relatively radioresistant tumors: a retrospective analysis

    NARCIS (Netherlands)

    Meyners, Thekla; Heisterkamp, Christine; Kueter, Jan-Dirk; Veninga, Theo; Stalpers, Lukas J. A.; Schild, Steven E.; Rades, Dirk

    2010-01-01

    This study investigated potential prognostic factors in patients treated with whole-brain irradiation (WBI) alone for brain metastases from relatively radioresistant tumors such as malignant melanoma, renal cell carcinoma, and colorectal cancer. Additionally, a potential benefit from escalating the

  1. The nature of variations in the radioresistance of sea urchin eggs in the early embryogenesis

    International Nuclear Information System (INIS)

    Konstantinova, M.M.; Tarasenko, A.G.; Nekrasova, I.V.; Dontsova, G.V.

    1975-01-01

    The synchronously developing sea urchin eggs (Strongylocentrotus nudus) have been used for the experiment. Radioprotective efficiency of cysteamine (applied in the concentrations ranging from 1.10 -5 to 5.10 -3 M) has been studied at two stages of mitosis: metaphase and telophase. Cysteamine (5.10 -3 M) has been found to level the variations in radiosensitivity of these phases producing the strongest effect in the radiosensitive phase (telophase) and the slightest effect in the radioresistant phase (metaphase). Determination of the relative protective effectiveness of cysteamine in relation to the original radiosensitivity of a cell, and, hence, to its thiol content, has demonstrated that the higher the radiosensitivity of a cell at the time of the exposure the higher the relative protective efficiency of cysteamine. The data obtained evidence of the idea that thiols play an essential role in the determination of radioresistance of different stages of mitosis of the developing sea urchin eggs

  2. Transmission of in-vitro radioresistance in a cancer-prone family

    International Nuclear Information System (INIS)

    Bech-Hansen, N.T.; Blattner, W.A.; Sell, B.M.; McKeen, E.A.; Lampkin, B.C.; Fraumeni, J.F. Jr.; Paterson, M.C.

    1981-01-01

    Neoplasms of possible radiogenic origin developed in two members of a family prone to a diversity of cancers. Gamma-irradiation survival studies in these two patients and three other relatives, but not their spouses, over three generations demonstrated resistance to cell killing. The D 10 value (radiation dose required to reduce survival to 10%) was significantly higher for the five radioresistant strains (491 +- 30 rad) than for control cultures (405 +- 18 rad). There was a significant correlation between individual D 10 values and D 0 survival-curve parameters, indicating that changes in the exponential slope of the survival curves accounted for much of the increase in D 10 values. This novel radiation phenotype could be a manifestation of a basic cellular defect, predisposing to a variety of tumours in family members. Thus in-vitro radioresistance, like radiosensitivity, may be a phenotype of a mechanism that increases cancer risk in man. (author)

  3. Highly radioresistant aramid fiber as a concrete-reinforcing material. Development of reinforced compound materials

    International Nuclear Information System (INIS)

    Udagawa, Akira; Moriya, Toshio.

    1997-01-01

    Nuclear installations, such as nuclear fusion reactor always receive strong influence from magnetic field. There, stray current is induced by the changes in magnetic fields among iron rods of the construction, resulting that the plasma control magnetic field might be disturbed. As the countermeasures for these troubles, iron rods mixed with non-magnetic Mn-steel have been used in JAERI, but it is insufficient to completely prevent such electromagnetic damages. Thus, aramid fiber reinforced plastics (ArFRP) was paid an attention as a concrete-reinforcing material. JAERI has been attempting to develop a radioresistant ArFRP jointly with Mitsui Construction Co., Ltd. and a highly efficient producing process of ArFRP was developed. The product had superior properties in respects of radioresistancy, heat-resistancy and durability. The properties of newly developed ArFRP rods were compared with those of the conventional ArFRP and iron rods. (M.N.)

  4. Clinically relevant radioresistant cells efficiently repair DNA double-strand breaks induced by X-rays

    International Nuclear Information System (INIS)

    Kuwahara, Yoshikazu; Baba, Taisuke; Nakagawa, Hironobu; Shimura, Tsutomu; Yamamoto, Yoichiro; Fukumoto, Manabu; Li Li; Ohkubo, Yasuhito

    2009-01-01

    Radiotherapy is one of the major therapeutic modalities for eradicating malignant tumors. However, the existence of radioresistant cells remains one of the most critical obstacles in radiotherapy and radiochemotherapy. Standard radiotherapy for tumor treatment consists of approximately 2 Gy once a day, 5 days a week, over a period of 5-8 weeks. To understand the characteristics of radioresistant cells and to develop more effective radiotherapy, we established a novel radioresistant cell line, HepG2-8960-R with clinical relevance from parental HepG2 cells by long-term fractionated exposure to 2 Gy of X-rays. HepG2-8960-R cells continued to proliferate with daily exposure to 2 Gy X-rays for more than 30 days, while all parental HepG2 cells ceased. After exposure to fractionated 2 Gy X-rays, induction frequencies of micronuclei and remaining foci of γ-H2AX in HepG2-8960-R were less than those in HepG2. Flow cytometric analysis revealed that the proportion of cells in S- and G2/M-phase of the cell cycle was higher in HepG2-8960-R than in HepG2. These suggest that the response of clinically relevant radioresistant (CRR) cells to fractionated radiation is not merely an accumulated response to each fractionated radiation. This is the first report on the establishment of a CRR cell line from an isogenic parental cell line. (author)

  5. Alterations in gene expression profiles between radioresistant and radiosensitive cell lines

    International Nuclear Information System (INIS)

    Zhou Fuxiang; Zhou Yunfeng; Xie Conghua; Dai Jing; Cao Zhen; Yu Haijun; Liao Zhengkai; Luo Zhiguo

    2007-01-01

    Objective: To study the-difference of gene expressions by the contrastive model including the cells with same pathological origin and genetic background, but definitely different radioresponse, and to find the main molecular targets related to radiosensitivity. Methods: Human larynx squamous carcinoma cell, Hep -2 was irradiated with dose of 637 cGy repeatedly to establish a radioresistant daughter cell line. The radiobiology characteristics were obtained using clone forming assay. The difference of gene expression between parent and daughter cells was detected by cDNA microarray using two different arrays including 14000 genes respectively. Results: A radioresistant cell strain Hep-2R was isolated from its parental strain Hep-2 cell. The SF 2 , D 0 , α, β for Hep-2R cell line were 0.6798, 3.24, 0.2951 and 0.0363, respectively, while 0.4148, 2.06, 0.1074 and 0.0405 for Hep-2, respectively (for SF 2 , χ 2 =63.957, P<0.001). Compared with Hep-2 cells, the expressions of 41 genes were significantly altered in the radioresistant Hep-2R cells, including 22 genes up-regulated and 19 genes down-regulated, which were involved in DNA repair, regulation of the cell cycle, cell proliferation, cytoskeleton, protein synthesis, cellular metabolism and especially apoptosis which is responsible for the different radiosensitivity between these two larynx cancer cells. The telomere protection protein gene, POT1, was the mostly up-regulated by 3.348 times. Conclusions: There is difference of gene expression between the radioresistant contrastive models. POT1 gene may be the target of radiosensitization. (authors)

  6. γ-irradiation induces radioresistant DNA synthesis in HeLa cells

    International Nuclear Information System (INIS)

    Synzynys, B.I.; Aminev, A.G.; Konstantinova, S.A.; Saenko, A.S.

    1987-01-01

    Cells of suspension HeLa culture at the logarithmic phase of growth were exposed to 60 Co-γ-rays (5 Gy), incubated in the nutritious medium, and in 4 h subjected to repeated irradiation: the dose-response function and the dynamics of DNA synthesis inhibition were determined. It was shown that DNA synthesis was inhibited to a lesser extent after preirradiation, in other words, DNA synthesis was radioresistant. A correlation between this synthesis and reproductive cell death is discussed

  7. Factors implicated to radioresistance of breast cancer and their possible roles

    International Nuclear Information System (INIS)

    Yan Weili; Huang Gang

    2006-01-01

    Radiotherapy plays an important role in the management of breast cancer. The recurrence of breast cancer after radiotherapy is considered to be related with radioresistance in breast cancer cells. Various factors, extranuclear and intranuclear, such as insulin-like growth factor-1 receptor, phosphatidylinositol 3-kinase pathway, epidermal growth factor, human epidermal growth factor receptors, p53, c-erb B2, Bcl-2, BRCA1, BRCA2, telomeres and gene expression signature, that have been implicated to influence the radiation response. (authors)

  8. Recovery and radio-resistance in mice after external irradiation; Restauration et radio-resistance chez la souris apres irradiation externe

    Energy Technology Data Exchange (ETDEWEB)

    Le Guillou, S [Commissariat a l' Energie Atomique, Fontenay-aux-Roses (France). Centre d' Etudes Nucleaires

    1965-07-01

    The author presents a literature study concerning recovery from external irradiation and an analysis of experimental data (which appear to suggest the idea of a radio-resistance in animals), as well as the hypotheses put forward for explaining this phenomenon. The author then describes an experiment carried out on mice whose LD 50/30 days increased from 1005 to 1380 rads and for which it was shown that an increase occurs in the number of certain anti-bodies circulating after a low dose of {gamma} irradiation. (author) [French] L'auteur presente une etude bibliographique de la restauration apres irradiation externe et une analyse des donnees experimentales qui paraissent suggerer la notion de radioresistance chez les animaux ainsi que les hypotheses cherchant a expliquer ce phenomene. Il relate ensuite une experience realisee sur des souris dont la DL 50/30 jours est passee de 1005 a 1380 rads et dans laquelle est montree l'augmentation de certains anticorps circulant apres une faible dose d'irradiation gamma. (auteur)

  9. Recovery and radio-resistance in mice after external irradiation; Restauration et radio-resistance chez la souris apres irradiation externe

    Energy Technology Data Exchange (ETDEWEB)

    Le Guillou, S. [Commissariat a l' Energie Atomique, Fontenay-aux-Roses (France). Centre d' Etudes Nucleaires

    1965-07-01

    The author presents a literature study concerning recovery from external irradiation and an analysis of experimental data (which appear to suggest the idea of a radio-resistance in animals), as well as the hypotheses put forward for explaining this phenomenon. The author then describes an experiment carried out on mice whose LD 50/30 days increased from 1005 to 1380 rads and for which it was shown that an increase occurs in the number of certain anti-bodies circulating after a low dose of {gamma} irradiation. (author) [French] L'auteur presente une etude bibliographique de la restauration apres irradiation externe et une analyse des donnees experimentales qui paraissent suggerer la notion de radioresistance chez les animaux ainsi que les hypotheses cherchant a expliquer ce phenomene. Il relate ensuite une experience realisee sur des souris dont la DL 50/30 jours est passee de 1005 a 1380 rads et dans laquelle est montree l'augmentation de certains anticorps circulant apres une faible dose d'irradiation gamma. (auteur)

  10. E-Cadherin loss associated with EMT promotes radioresistance in human tumor cells

    International Nuclear Information System (INIS)

    Theys, Jan; Jutten, Barry; Habets, Roger; Paesmans, Kim; Groot, Arjan J.; Lambin, Philippe; Wouters, Brad G.; Lammering, Guido; Vooijs, Marc

    2011-01-01

    Background and purpose: Hypoxia is a hallmark of solid cancers and associated with metastases and treatment failure. During tumor progression epithelial cells often acquire mesenchymal features, a phenomenon known as epithelial-to-mesenchymal transition (EMT). Intratumoral hypoxia has been linked to EMT induction. We hypothesized that signals from the tumor microenvironment such as growth factors and tumor oxygenation collaborate to promote EMT and thereby contribute to radioresistance. Materials and methods: Gene expression changes under hypoxia were analyzed using microarray and validated by qRT-PCR. Conversion of epithelial phenotype upon hypoxic exposure, TGFβ addition or oncogene activation was investigated by Western blot and immunofluorescence. Cell survival following ionizing radiation was assayed using clonogenic survival. Results: Upon hypoxia, TGFβ addition or EGFRvIII expression, MCF7, A549 and NMuMG epithelial cells acquired a spindle shape and lost cell-cell contacts. Expression of epithelial markers such as E-cadherin decreased, whereas mesenchymal markers such as vimentin and N-cadherin increased. Combining hypoxia with TGFβ or EGFRvIII expression, lead to more rapid and pronounced EMT-like phenotype. Interestingly, E-cadherin expression and the mesenchymal appearance were reversible upon reoxygenation. Mesenchymal conversion and E-cadherin loss were associated with radioresistance. Conclusions: Our findings describe a mechanism by which the tumor microenvironment may contribute to tumor radioresistance via E-cadherin loss and EMT.

  11. Energetic heavy ions overcome tumor radioresistance caused by overexpression of Bcl-2

    International Nuclear Information System (INIS)

    Hamada, Nobuyuki; Hara, Takamitsu; Omura-Minamisawa, Motoko; Funayama, Tomoo; Sakashita, Tetsuya; Sora, Sakura; Yokota, Yuichiro; Nakano, Takashi

    2008-01-01

    Background and purpose: Overexpression of Bcl-2 is frequent in human cancers and has been associated with radioresistance. Here we investigated the potential impact of heavy ions on Bcl-2 overexpressing tumors. Materials and methods: Bcl-2 cells (Bcl-2 overexpressing HeLa cells) and Neo cells (neomycin resistant gene-expressing HeLa cells) exposed to γ-rays or heavy ions were assessed for the clonogenic survival, apoptosis and cell cycle distribution. Results: Whereas Bcl-2 cells were more resistant to γ-rays (0.2 keV/μm) and helium ions (16.2 keV/μm) than Neo cells, heavy ions (76.3-1610 keV/μm) yielded similar survival regardless of Bcl-2 overexpression. Carbon ions (108 keV/μm) decreased the difference in the apoptotic incidence between Bcl-2 and Neo cells, and prolonged G 2 /M arrest that occurred more extensively in Bcl-2 cells than in Neo cells. Conclusions: High-LET heavy ions overcome tumor radioresistance caused by Bcl-2 overexpression, which may be explained at least in part by the enhanced apoptotic response and prolonged G 2 /M arrest. Thus, heavy-ion therapy may be a promising modality for Bcl-2 overexpressing radioresistant tumors

  12. Cytotoxicity and radiosensitization effect of TRA-8 on radioresistant human larynx squamous carcinoma cells.

    Science.gov (United States)

    Wu, F; Hu, Y; Long, J; Zhou, Y J; Zhong, Y H; Liao, Z K; Liu, S Q; Zhou, F X; Zhou, Y F; Xie, C H

    2009-02-01

    TRAIL induces apoptosis in a variety of tumorigenic and transformed cell lines, but not in many normal cells. Recent studies have demonstrated that death receptor 5 (DR5), one of the two death receptors bound by TRAIL, showed expression in most malignantly transformed cells. This study evaluated effects of a monoclonal antibody (TRA-8) to human death receptor 5, combined with ionizing radiation, on radioresistant human larynx squamous carcinoma cell line (Hep-2R). Cells were treated with TRA-8 alone or in combination with radiation, cell viability inhibition was measured by MTT assay, and the induction of apoptosis was determined by Annexin V staining. Radionsensitivity of Hep-2R cells treated with TRA-8 were investigated with long-term clonogenic assays. Regulation of DR5 expression in cells after radiation was analyzed by indirect immunofluorescence using murine TRA-8 in combination with flow cytometry. The results suggested that TRA-8 enhanced radionsensitivity of Hep-2R cells, and that TRA-8 regulated Hep-2R cell cycle arrest at G2/M phase. Irradiation up-regulated the expression of DR5, and when combined with TRA-8 yielded optimal survival benefit. Therefore, TRA-8 can be used in combination with irradiation in radioresistant human larynx squamous carcinoma cells. Monoclonal antibodies such as TRA-8 may play an important role in the development of an effective treatment strategy for patients with radioresistant cancers.

  13. Dexamethasone-induced radioresistance occurring independent of human papilloma virus gene expression in cervical carcinoma cells

    International Nuclear Information System (INIS)

    Rutz, H.P.; Mariotta, M.; Mirimanoff, R.O.; Knebel Doeberitz, M. von

    1998-01-01

    The aim of this study was to investigate the role of HPV 18 E6 and E7 gene products with respect to radiosensitivity of two cervical carcinoma cell lines. The two cervical carcinoma lines C4-1 and SW 756 were used in which treatment with dexamethasone allows to modulate expression levels of HPV 18 E6 and E7 genes: Upregulation in C4-1, down-regulation in SW 756. Effects of treatment with dexamethasone on plating efficiency and radiosensitivity were assessed using a clonogenic assay. Treatment with dexamethasone increased plating efficiency of the C4-1 cells, but did not affect plating efficiency of SW 756 cells. Treatment with dexamethasone induced enhanced radioresistance in both cell lines. Thus, in C4-1 cells the observed changes in radioresistance correlate to the enhancement in expression of HPV 18 genes E6/E7, whereas in SW 756, a reduced expression correlates negatively with the enhanced radioresistance. (orig./MG) [de

  14. Sensitization of Radioresistant Prostate Cancer Cells by Resveratrol Isolated from Arachis hypogaea Stems.

    Science.gov (United States)

    Chen, Yu-An; Lien, Hsiu-Man; Kao, Min-Chuan; Lo, U-Ging; Lin, Li-Chiung; Lin, Chun-Jung; Chang, Sheau-Jiun; Chen, Chia-Chang; Hsieh, Jer-Tsong; Lin, Ho; Tang, Chih-Hsin; Lai, Chih-Ho

    2017-01-01

    Resveratrol (RV, 3,4',5-trihydroxystilbene) is naturally produced by a wide variety of plants including grapes and peanuts (Arachis hypogaea). However, the yield of RV from peanut stem and its potential radiosensitizing effects in prostate cancer (PCa) have not been well investigated. In this study, we characterized RV in peanut stem extract (PSE) for the first time and showed that both RV and PSE dose-dependently induced cell death in DOC-2/DAB2 interactive protein (DAB2IP)-deficient PCa cells with the radioresistant phenotype. Furthermore, the combination of radiation with either RV or PSE induced the death of radioresistant PCa cells through delayed repair of radiation-induced DNA double-strand break (DSB) and prolonged G2/M arrest, which induced apoptosis. The administration of RV and PSE effectively enhanced radiation therapy in the shDAB2IP PCa xenograft mouse model. These results demonstrate the promising synergistic effect of RV and PSE combined with radiation in the treatment of radioresistant PCa.

  15. GPR56/ADGRG1 Inhibits Mesenchymal Differentiation and Radioresistance in Glioblastoma

    Directory of Open Access Journals (Sweden)

    Marta Moreno

    2017-11-01

    Full Text Available A mesenchymal transition occurs both during the natural evolution of glioblastoma (GBM and in response to therapy. Here, we report that the adhesion G-protein-coupled receptor, GPR56/ADGRG1, inhibits GBM mesenchymal differentiation and radioresistance. GPR56 is enriched in proneural and classical GBMs and is lost during their transition toward a mesenchymal subtype. GPR56 loss of function promotes mesenchymal differentiation and radioresistance of glioma initiating cells both in vitro and in vivo. Accordingly, a low GPR56-associated signature is prognostic of a poor outcome in GBM patients even within non-G-CIMP GBMs. Mechanistically, we reveal GPR56 as an inhibitor of the nuclear factor kappa B (NF-κB signaling pathway, thereby providing the rationale by which this receptor prevents mesenchymal differentiation and radioresistance. A pan-cancer analysis suggests that GPR56 might be an inhibitor of the mesenchymal transition across multiple tumor types beyond GBM.

  16. Acquired radioresistance of cancer and the AKT/GSK3β/cyclin D1 overexpression cycle

    International Nuclear Information System (INIS)

    Shimura, Tsutomu

    2011-01-01

    Fractionated radiotherapy (RT) is widely used in cancer therapy for its advantages in the preservation of normal tissues. However, repopulation of surviving tumor cells during fractionated RT limits the efficacy of RT. In fact, repopulating tumors often acquire radioresistance and this is the major cause of failure of RT. We have recently demonstrated that human tumor cells acquire radioresistance when exposed to fractionated radiation (FR) of X-rays every 12 hours for 1 month. The acquired radioresistance was associated with overexpression of cyclin D1, a result of a series of molecular changes; constitutive activation of DNA-PK and AKT with concomitant down-regulation of glycogen synthase kinase-3β (GSK3β) which results in suppression of cyclin D1 proteolysis. Aberrant cyclin D1 overexpression in S-phase induced DNA double strand breaks which activated DNA-PK and established the vicious cycle of cycling D1 overexpression. This overexpression of cyclin D1 is responsible for the radioresistance phenotype of long-term FR cells, since this phenotype was completely abrogated by treatment of FR cells by the AKT/PKB signaling inhibitor (API-2), an AKT inhibitor or by a Cdk4 inhibitor. Thus, targeting the AKT/GSK3β/cyclin D1/Cdk4 pathway can be an efficient modality to suppress acquired radioresistance of tumor cells. In this article, I overview the newly discovered molecular mechanisms underlying acquired radioresistance of tumor cells induced by FR, and propose a strategy for eradication of tumors using fractionated RT by overcoming tumor radioresistance. (author)

  17. TGF-β and Hypoxia/Reoxygenation Promote Radioresistance of A549 Lung Cancer Cells through Activation of Nrf2 and EGFR

    Directory of Open Access Journals (Sweden)

    Sae-lo-oom Lee

    2016-01-01

    Full Text Available Although many studies have examined the roles of hypoxia and transforming growth factor- (TGF- β separately in the tumor microenvironment, the effects of simultaneous treatment with hypoxia/reoxygenation and TGF-β on tumor malignancy are unclear. Here, we investigated the effects of redox signaling and oncogenes on cell proliferation and radioresistance in A549 human lung cancer cells in the presence of TGF-β under hypoxia/reoxygenation conditions. Combined treatment with TGF-β and hypoxia activated epidermal growth factor receptor (EGFR and nuclear factor (erythroid-derived 2-like 2 (Nrf2, a redox-sensitive transcription factor. Interestingly, Nrf2 knockdown suppressed the effects of combined treatment on EGFR phosphorylation. In addition, blockade of EGFR signaling also suppressed induction of Nrf2 following combined treatment with hypoxia and TGF-β, indicating that the combined treatment induced positive crosstalk between Nrf2 and EGFR. TGF-β and hypoxia/reoxygenation increased the accumulation of reactive oxygen species (ROS, while treatment with N-acetyl-L-cysteine abolished the activation of Nrf2 and EGFR. Treatment with TGF-β under hypoxic conditions increased the proliferation of A549 cells compared with that after vehicle treatment. Moreover, cells treated with the combined treatment exhibited resistance to ionizing radiation (IR, and knockdown of Nrf2 increased IR-induced cell death under these conditions. Thus, taken together, our findings suggested that TGF-β and hypoxia/reoxygenation promoted tumor progression and radioresistance of A549 cells through ROS-mediated activation of Nrf2 and EGFR.

  18. Transient elevation of glycolysis confers radio-resistance by facilitating DNA repair in cells

    International Nuclear Information System (INIS)

    Bhatt, Anant Narayan; Chauhan, Ankit; Khanna, Suchit; Rai, Yogesh; Singh, Saurabh; Soni, Ravi; Kalra, Namita; Dwarakanath, Bilikere S

    2015-01-01

    Cancer cells exhibit increased glycolysis for ATP production (the Warburg effect) and macromolecular biosynthesis; it is also linked with therapeutic resistance that is generally associated with compromised respiratory metabolism. Molecular mechanisms underlying radio-resistance linked to elevated glycolysis remain incompletely understood. We stimulated glycolysis using mitochondrial respiratory modifiers (MRMs viz. di-nitro phenol, DNP; Photosan-3, PS3; Methylene blue, MB) in established human cell lines (HEK293, BMG-1 and OCT-1). Glucose utilization and lactate production, levels of glucose transporters and glycolytic enzymes were investigated as indices of glycolysis. Clonogenic survival, DNA repair and cytogenetic damage were studied as parameters of radiation response. MRMs induced the glycolysis by enhancing the levels of two important regulators of glucose metabolism GLUT-1 and HK-II and resulted in 2 fold increase in glucose consumption and lactate production. This increase in glycolysis resulted in resistance against radiation-induced cell death (clonogenic survival) in different cell lines at an absorbed dose of 5 Gy. Inhibition of glucose uptake and glycolysis (using fasentin, 2-deoxy-D-glucose and 3-bromopyruvate) in DNP treated cells failed to increase the clonogenic survival of irradiated cells, suggesting that radio-resistance linked to inhibition of mitochondrial respiration is glycolysis dependent. Elevated glycolysis also facilitated rejoining of radiation-induced DNA strand breaks by activating both non-homologous end joining (NHEJ) and homologous recombination (HR) pathways of DNA double strand break repair leading to a reduction in radiation-induced cytogenetic damage (micronuclei formation) in these cells. These findings suggest that enhanced glycolysis generally observed in cancer cells may be responsible for the radio-resistance, partly by enhancing the repair of DNA damage

  19. Enhanced radiation response in radioresistant MCF-7 cells by targeting peroxiredoxin II

    Directory of Open Access Journals (Sweden)

    Diaz AJG

    2013-10-01

    Full Text Available Anthony Joseph Gomez Diaz,1 Daniel Tamae,2 Yun Yen,3 JianJian Li,4 Tieli Wang1 1Department of Chemistry and Biochemistry, California State University at Dominguez Hills, Carson, CA, 2Center of Excellence in Environmental Toxicology, Department of Pharmacology, University of Pennsylvania, Philadelphia, PA, 3Department of Clinical and Molecular Pharmacology, Beckman Research Institute of City of Hope National Medical Center, Duarte, CA, 4Department of Radiation Oncology, University of California Davis, Sacramento, CA, USA Abstract: In our previous study, we identified that a protein target, peroxiredoxin II (PrxII, is overexpressed in radioresistant MCF+FIR3 breast-cancer cells and found that its expression and function is associated with breast-cancer radiation sensitivity or resistance. Small interference RNA (siRNA targeting PrxII gene expression was able to sensitize MCF+FIR3 radioresistant breast-cancer cells to ionizing radiation. The major focus of this work was to investigate how the radiation response of MCF+FIR3 radioresistant cells was affected by the siRNA that inhibits PrxII gene expression. Our results, presented here, show that silencing PrxII gene expression increased cellular toxicity by altering cellular thiol status, inhibiting Ca2+ efflux from the cells, and perturbing the intracellular Ca2+ homeostasis. By combining radiotherapy and siRNA technology, we hope to develop new therapeutic strategies that may have potential to enhance the efficacy of chemotherapeutic agents due to this technology's property of targeting to specific cancer-related genes. Keywords: siRNA, PrxII, radiation resistance, Ca2+, MCF+FIR3

  20. Metabolism of the chemo antibiotic combination sulphamethoxazol and trimethoprim by some radioresistant strains

    International Nuclear Information System (INIS)

    Zahiera, T.S.

    1990-01-01

    The radioresistant mutants B. Firmus, B. Laterosporus, B. Megaterium, M. Roseus and M. Luteus were tested microbiologically for their sensitivity to a drug consisting of the chemo antibiotic combination of sulphamethoxazole (SMZ) and trimethoprim (TMP) in a ratio of 20:1. All the studied mutant strains were found to be insensitive to this combination of antibiotics except the radioresistant mutant strain of M.roseus. The mechanism of the inactivation of both SMZ and TMP by the radioresistant mutants of B. Laterosporus, B. Firmus, and M.Luteus was studied. The drug was incubated with each of these mutants for different periods of time to study its degradation. High performance liquid chromatography and microbiological assay techniques were used to determine the activity and the pathway of the consumption of the drug after its incubation with these three mutants for time. The results indicated that the drug acts in a synergistic effect on all the studied mutants. Only a part of both molecules of SMZ and TMP was utilized by the studied mutant strains. The ratio of the left over of SMZ/TMP were found to be 6,6 and 8 after seven days incubation periods and 12, 7.5 and 19 after two weeks incubation periods with B. Laterosporus, B. Firmus, and M. Luteus mutants respectively. The microbial activity of the extracted drug for bacilli strains isolated from clean environment had not changed significantly due to incubation with the mutants, but it was decreased for M. Luteus strain. The drug inactivation by the studied mutant strains seemed to be due to decreased affinities to SMZ and TMP, and to formation of an altered 7,8 dihydropteroate synthetase and dihydrofolate reductase

  1. The heat shock proteins at the increasing of the radioresistance of silkworm embryo Bombyx Moril

    International Nuclear Information System (INIS)

    Agaev, F.A.; Garibov, A.A.; Aliev, D.I.; Alieva, I.N.

    2002-01-01

    The aim of this study is revealing the role of Heat Shock Proteins (HSP) at the radio-modification effect of Heat Shock (HS) on the silkworm embryo. Our preliminary study was indicated that 3-daily silkworm embryo is more than 10-12 times sensitive to gamma-radiation in comparative to 7-daily embryo. Investigation of the HS effect on the radiosensitivity of the embryo indicates that thermal treatment (40 deg. C) of 3 daily embryo during 60 min before irradiation leads the increasing of its radioresistance. At the same time, the HS treatment immediately after irradiation capable increases strike affect of irradiation. LD 50 for heat treated embryo before and after irradiation consists of 46.7 and 19.0 Gy, correspondingly. For embryo irradiated without heat treatment LD 50 is 29.5 Gy. Identical effects are observed for 7-daily embryo. Increasing of the radioresistance by HS before irradiation, obviously, may be explained by the embryo cell reply to the stress factor and capable initiated by different biochemical shifts, for example, by induction of HPS synthesis. According to the results of carried out experiments HS treatment leads to the induction or increasing of the HSP synthesis into this embryo. Protein with molecular mass 70 kDa (HSP-70 kDa) has been synthesised de novo. The synthesis of the other two proteins (HSP-83 kDa and HSP-68 kDa) significantly increases at the high temperature. It is noted, that HSP-70 kDa consists of 55-60 % of whole included radioactive mark. Identical induction was observed in the experiments at the combined effect both HS and gamma-radiation on the embryo. At the post-radiation heat treatment the induction of HSP synthesis is observed, too. It was concluded that damages induced by irradiation can not prevent HSP induction into embryo. The result of comparative analysis was shown that in 3-daily embryo in spite of 7-daily embryo the synthesis of HSP is more intensive and correlated with the radio- modification effect of HS. The

  2. Rate of oxygen consumption of hamster melanoma cells as a factor influencing their radioresistance

    International Nuclear Information System (INIS)

    Pajak, S.; Subczynski, W.; Panz, T.; Lukiewicz, S.

    1980-01-01

    It has been reported in recent years that the level of radiosensitivity of neoplasmic cells in vivo and of sphaeroids in vitro can be modified by controlling their rate of oxygen consumption. Thus, an attempt was made to compare this rate in the case of the melanotic and amelanotic lines of Bomirski hamster melanoma in vitro, as it is known that these two lines distinctly differ in their reactivity to ionizing radiations. The measurements carried out by the use of a new ESR method revealed that pigmented and pigmentless cells consume oxygen at significantly different rates. This means that oxygen utilization may contribute to the overall level of radioresistance of melanoma cells. (author)

  3. Alterations in radioresistance of eucaryotic cells after the transfer of genomic wildtype DNA and metallothionein genes

    International Nuclear Information System (INIS)

    Lohrer, H.

    1987-01-01

    The presented paper describes experiments concerning the alteration of radiosensitivity of eucaryotic cells after gene transfer. Ionizing radiation (γ- or X-ray) induces DNA single- or double strand breaks, which are religated by an unknown repair system. Repair deficient cells are highly sensitive to ionizing radiation. In the experiments described, cells from a patient with the heritable disease Ataxia telangiectasia were used as well as two X-ray sensitive CHO mutant cell lines. After gene transfer of an intact human DNA repair gene or a metallothionein gene the cells should regain radioresistance. (orig.) [de

  4. The increase in radioresistance of Chinese hamster cells cultured as spheroids is correlated to changes in nuclear morphology

    International Nuclear Information System (INIS)

    Gordon, D.J.; Milner, A.E.; Beaney, R.P.; Grdina, D.J.; Vaughan, A.T.

    1990-01-01

    Chinese hamster V79 cells grown as spheroids in roller culture are more radioresistant than those grown as monolayers. The supercoiled structure of chromatin, as salt-extracted nucleoids, has been examined using flow cytometry. Irradiated viable cells from spheroid culture contain restraints to supercoil relaxation that are absent in monolayer cells. Further analysis of the chromatin organization from each growth form shows that the radioresistant spheroid cells contain a DNA-protein matrix that is more resistant to detergent-induced degradation. The increase in structural integrity may be due to the retention of a 55-60 kDa protein that is apparent in the nucleoids of spheroid, but not monolayer cells. The increase in structural integrity of the spheroid cells may explain their greater radioresistance by providing a more stable platform for high-fidelity DNA damage repair

  5. Radioresistant CD4+ T cells in normal, unprimed mice, with verification of the Bergonie-Tribondeau law

    International Nuclear Information System (INIS)

    Makidono, Reiko; Ito, Akira.

    1997-01-01

    This is the first report on radioresistant CD4+ T cells found in normal, unprimed mice. After sublethal whole body irradiation, regular CD4+ as well as primitive NK1.1+ CD4+ T cells were enriched in the spleen. Since it has been well established that virgin T and B cells are highly radiosensitive, these cells were once assumed to be a unique lymphocyte population for which radiosensitivity does not follow the general law of radiation sensitivity for mammalian cells (Bergonie-Tribondeau law). These cells exhibited higher proliferative response to accessory cells than the non-irradiated control cells in the syngeneic mixed leukocyte reaction (SMLR). This indicated that virgin CD4+ T cells sensitized to, and readily respond to self-MHC class II molecules are radioresistant, and that their radioresistance, as activated cells, is consistent with the Bergonie-Tribondeau law. (author)

  6. Sister chromatid exchanges in X-ray irradiated blood lymphocytes from patients with hereditary diseases with radioresistant DNA synthesis

    International Nuclear Information System (INIS)

    Pleskach, N.M.; Andriadze, M.I.; Mikhel'son, V.M.; Zhestyanikov, V.D.

    1988-01-01

    X-ray irradiation induced sister chromatid exchanges (SCE) in blood lymphocytes from patient with Down's syndrome and adult progeria (in both the cases radioresistant DNA synthesis takes place). In normal lymphocytes (in which ionizing radiation inhibits the replicative synthesis of DNA) the rate of SCE rises with the rise of radiation dose. Thus, the rate of SCE in X-ray irradiated lymphocytes is in reverse dependence with radioresistance of replicative synthesis of DNA. The data obtained are explained in accordance with the replicative hypothesis of the SCE nature (Painter, 1980a): in cells of patients with Down's syndrome, xeroderma pigmentosum from 2 and progeria of adults the time of existence of partly replicated clusters of replicons is decreased due to radioresistant replicative synthesis of DNA, but the presence of partly replicated clusters of replicons in necessary for SCE formation. Therefore the rate of SCF in X-irradiated cells of these patients decreases

  7. Radioresistant cell strain of human fibrosarcoma cells obtained after long-term exposure to X-rays

    International Nuclear Information System (INIS)

    Wei, K.; Kodym, R.

    1998-01-01

    A radioresistant cell strain from human fibrosarcoma HT1080 has been obtained after prolonged exposure to x-rays for 7 months (2 Gy per day, 5 days per week). This new strain, HT1080R, differs from HT1080 in a significantly increased ability of clonogenical survival, with coefficient α decreasing from 0.161 to 0.123 Gy -1 and coefficient β decreasing from 0.0950 to 0.0565 Gy -2 . Furthermore, the radioresistance of HT1080R proved to be stable in long-term passaged cultures as well as in frozen samples. Differences between the two cell lines are also observed in the G-banded karyotype; the new cell line shows monosomy of chromosome 17 and loss of 5p + and 11q + present in the parental cells. These data suggest that the radioresistance may have been caused by radiation-induced cell mutation and that the resistant cells may have been selected by repeated irradiations. In order to characterize this new strain, the ability of the cells to rejoin DNA double-strand breaks, the cell cycle distribution and the amount of apoptosis after irradiation have been estimated; however, no differences are observed between these two cell strains. Although the mechanism of the elevated radioresistance remains unknown, this pair of cell strains can provide a new model system for further investigations with regard to the mechanisms of cellular radioresistance. The results also show that any type of irradiation similar to the schedules used in radiotherapy can lead to the formation and selection of more radioresistant cell clones in vitro, a phenomenon with possible implications for radiotherapy. (orig.)

  8. Breast cancer stem cell-like cells generated during TGFβ-induced EMT are radioresistant.

    Science.gov (United States)

    Konge, Julie; Leteurtre, François; Goislard, Maud; Biard, Denis; Morel-Altmeyer, Sandrine; Vaurijoux, Aurélie; Gruel, Gaetan; Chevillard, Sylvie; Lebeau, Jérôme

    2018-05-04

    Failure of conventional antitumor therapy is commonly associated with cancer stem cells (CSCs), which are often defined as inherently resistant to radiation and chemotherapeutic agents. However, controversy about the mechanisms involved in the radiation response remains and the inherent intrinsic radioresistance of CSCs has also been questioned. These discrepancies observed in the literature are strongly associated with the cell models used. In order to clarify these contradictory observations, we studied the radiosensitivity of breast CSCs using purified CD24 -/low /CD44 + CSCs and their corresponding CD24 + /CD44 low non-stem cells. These cells were generated after induction of the epithelial-mesenchymal transition (EMT) by transforming growth factor β (TGFβ) in immortalized human mammary epithelial cells (HMLE). Consequently, these 2 cellular subpopulations have an identical genetic background, their differences being related exclusively to TGFβ-induced cell reprogramming. We showed that mesenchymal CD24 -/low /CD44 + CSCs are more resistant to radiation compared with CD24 + /CD44 low parental cells. Cell cycle distribution and free radical scavengers, but not DNA repair efficiency, appeared to be intrinsic determinants of cellular radiosensitivity. Finally, for the first time, we showed that reduced radiation-induced activation of the death receptor pathways (FasL, TRAIL and TNF-α) at the transcriptional level was a key causal event in the radioresistance of CD24 -/low / CD44+ cells acquired during EMT.

  9. The effect of caffeine on x-ray repair of radioresistant HeLa cells

    International Nuclear Information System (INIS)

    Kubo, Kihei; Koiwai, Soichiro; Morita, Kazuo

    1985-01-01

    The contribution of caffeine-modifiable repair process to the radiosensitivity of a radioresistant HeLa strain (RC-355) has been investigated in comparison with control HeLa strain (CC-24). Both the final slope and the shoulder of X-ray survival curve for log-phase cells were affected by caffeine posttreatment. When the treatment with 10 mM caffeine delayed, an increase in survival was observed with increasing interval between irradiation and the treatment. During first several hours of the repair interval, the steepness of the final slope of survival curve decreased rapidly, and rate of the decrease was found to be higher in RC-355 than in CC-24 cells. Longer time (24 hours or more) before the initiation of caffeine treatment was required for the complete recovery of the shoulder. When the cells were incubated in plateau-phase after irradiation, an appreciable increase in survival was observed in comparison with when plated immediately following X-ray. The increase was found to be greater for RC-355 than for CC-24. The results suggest that the radioresistant RC-355 cells repaired more X-ray-induced PLD than CC-24 cells did. (author)

  10. Isolation and characterization of radioresistant mutants in Bacillus subtilis and Bacillus thuringiensis

    International Nuclear Information System (INIS)

    Kalinin, V.L.; Petrov, V.N.; Petrova, T.M.

    1981-01-01

    Vegetative cells of Bac. thuringiensis var. galleriae (the wild-type strain 351) are much more sensitive to lethal effects of UV light and 60 Co-γ-rays than those of Bac. subtilis (the wild-type strain 168). This difference is less pronounced for spores of these strains. By means of repeated γ-irradiation-regrowth cycles radioresistant mutants Bac. thuringiensis Gamsup(r) 14 and Bac. subtilis Gamsup(r) 9 were selected. The vegetative cells of these mutants are correspondingly 19 times and 3.9 times more resistant to lethal effects of γ-radiation than the cells of the parental strains. The resistance of the Gamsup(r) mutant cells to lethal effects of UV light and H 2 O 2 is also increased. The spores of the Gamsup(r) 14 mutant are 1.5-1.7 times more resistant to γ-radiation and UV light than the wild-type spores. The radioresistant mutants and the parental strains do not vary in their capacity for host-cell reactivation of UV- or γ-irradiated phages Tg13 and 105

  11. Potentially lethal damage repair in cell lines of radioresistant human tumours and normal skin fibroblasts

    International Nuclear Information System (INIS)

    Marchese, M.J.; Minarik, L.; Hall, E.J.; Zaider, M.

    1985-01-01

    Radiation cell survival data were obtained in vitro for three cell lines isolated from human tumours traditionally considered to be radioresistant-two melanomas and one osteosarcoma-as well as from a diploid skin fibroblast cell line. One melanoma cell line was much more radioresistant than the other, while the osteosarcoma and fibroblast cell lines were more radiosensitive than either. For cells growing exponentially, little potentially lethal damage repair (PLDR) could be demonstrated by comparing survival data for cells in which subculture was delayed by 6 h with those sub-cultured immediately after treatment. For the malignant cells in plateau phase, which in these cells might be better termed 'slowed growth phase', since an appreciable fraction of the cells are still cycling, a small amount of PLDR was observed, but not as much as reported by other investigators in the literature. The normal fibroblasts, which achieved a truer plateau phase in terms of noncycling cells, showed a significantly larger amount of PLDR than the tumour cells. (author)

  12. 9-β-arabinofuranosyladenine preferentially sensitizes radioresistant squamous cell carcinoma cell lines to x-rays

    International Nuclear Information System (INIS)

    Heaton, D.

    1992-06-01

    The effect of 9-β-arabinofuranosyladenine (ara-A) on sensitivity to the deleterious effects of x-rays was studied in six squamous cell carcinoma cell lines. Three lines were relatively radioresistant, having D 0 values of 2.31 to 2.89 Gy, and the other three lines were relatively radiosensitive, having D 0 values of between 1.07 and 1.45 Gy. Ara-A (50 or 500 μM) was added to cultures 30 min prior to irradiation and removed 30 min after irradiation, and sensitivity was measured in terms of cell survival. The radiosensitizing effect of ara-A was very dependent on the inherent radiosensitivity of the tumor cell line. Fifty micromolar concentrations of ara-A sensitized only the two most radioresistant lines, SCC-12B.2 and JSQ-3. Five hundred micromolar concentrations of ara-A sensitized the more sensitive cell lines, SQ-20B and SQ-9G, but failed to have any effect on the radiation response of the two most sensitive cell lines, SQ-38 and SCC-61. Concentrations of ara-A as low as 10 μM were equally efficient in inhibiting DNA synthesis in all six cell lines. These results suggest that the target for the radiosensitizing effect of ara-A is probably related to the factor controlling the inherent radiosensitivity of human tumor cells. Therefore, ara-A might be useful in overcoming radiation resistance in vivo

  13. 9-{beta}-arabinofuranosyladenine preferentially sensitizes radioresistant squamous cell carcinoma cell lines to x-rays

    Energy Technology Data Exchange (ETDEWEB)

    Heaton, D. [Rush Univ. Medical Center, Chicago, IL (United States). Therapeutic Radiology; Mustafi, R. [Chicago Univ., IL (United States). Dept. of Radiation and Cellular Oncology; Schwartz, J.L. [Chicago Univ., IL (United States). Dept. of Radiation and Cellular Oncology]|[Argonne National Lab., IL (United States)

    1992-06-01

    The effect of 9-{beta}-arabinofuranosyladenine (ara-A) on sensitivity to the deleterious effects of x-rays was studied in six squamous cell carcinoma cell lines. Three lines were relatively radioresistant, having D{sub 0} values of 2.31 to 2.89 Gy, and the other three lines were relatively radiosensitive, having D{sub 0} values of between 1.07 and 1.45 Gy. Ara-A (50 or 500 {mu}M) was added to cultures 30 min prior to irradiation and removed 30 min after irradiation, and sensitivity was measured in terms of cell survival. The radiosensitizing effect of ara-A was very dependent on the inherent radiosensitivity of the tumor cell line. Fifty micromolar concentrations of ara-A sensitized only the two most radioresistant lines, SCC-12B.2 and JSQ-3. Five hundred micromolar concentrations of ara-A sensitized the more sensitive cell lines, SQ-20B and SQ-9G, but failed to have any effect on the radiation response of the two most sensitive cell lines, SQ-38 and SCC-61. Concentrations of ara-A as low as 10 {mu}M were equally efficient in inhibiting DNA synthesis in all six cell lines. These results suggest that the target for the radiosensitizing effect of ara-A is probably related to the factor controlling the inherent radiosensitivity of human tumor cells. Therefore, ara-A might be useful in overcoming radiation resistance in vivo.

  14. Nicotine enhances proliferation, migration, and radioresistance of human malignant glioma cells through EGFR activation

    International Nuclear Information System (INIS)

    Khalil, A.A.; Jameson, M.J.; Broaddus, W.C.; Lin, P.S.; Chung, T.D.

    2013-01-01

    It has been suggested that continued tobacco use during radiation therapy contributes to maintenance of neoplastic growth despite treatment with radiation. Nicotine is a cigarette component that is an established risk factor for many diseases, neoplastic and otherwise. The hypothesis of this work is that nicotine promotes the proliferation, migration, and radioresistance of human malignant glioma cells. The effect of nicotine on cellular proliferation, migration, signaling, and radiation sensitivity were evaluated for malignant glioma U87 and GBM12 cells by use of the AlamarBlue, scratch healing, and clonogenic survival assays. Signal transduction was assessed by immunoblotting for activated EGFR, extracellular regulated kinase (ERK), and AKT. At concentrations comparable with those found in chronic smokers, nicotine induced malignant glioma cell migration, growth, colony formation, and radioresistance. Nicotine increased phosphorylation of EGFR tyr992 , AKT ser473 , and ERK. These molecular effects were reduced by pharmacological inhibitors of EGFR, PI3K, and MEK. It was therefore concluded that nicotine stimulates the malignant behavior of glioma cells in vitro by activation of the EGFR and downstream AKT and ERK pathways. (author)

  15. Radioresistant DNA synthesis in cells of patients showing increased chromosomal sensitivity to ionizing radiation

    International Nuclear Information System (INIS)

    Barenfeld, L.S.; Pleskach, N.M.; Bildin, V.N.; Prokofjeva, V.V.; Mikhelson, V.M.

    1986-01-01

    The rate of DNA synthesis after γ-irradiation was studied either by analysis of the steady-state distribution of daughter [ 3 H]DNA in alkaline sucrose gradients or by direct assay of the amount of [ 3 H]thymidine incorporated into DNA of fibroblasts derived from a normal donor (LCH882) and from Down's syndrome (LCH944), Werner's syndrome (WS1LE) and xeroderma pigmentosum (XP2LE) patients with chromosomal sensitivity to ionizing radiation. Doses of γ-irradiation that markedly inhibited the rate of DNA synthesis in normal human cells caused almost no inhibition of DNA synthesis in the cells from the affected individuals. The radioresistant DNA synthesis in Down's syndrome cells was mainly due to a much lower inhibition of replicon initiation than that in normal cells; these cells were also more resistant to damage that inhibited replicon elongation. Our data suggest that radioresistant DNA synthesis may be an intrinsic feature of all genetic disorders showing increased radiosensitivity in terms of chromosome aberrations. (orig.)

  16. Selection of radioresistant cells by vitamin A deficiency in a small cell lung cancer cell line

    International Nuclear Information System (INIS)

    Terasaki, Takeo; Shimosato, Yukio; Wada, Makio; Yokota, Jun; Terada, Masaaki

    1990-01-01

    Radiation sensitivity of a human small cell lung cancer cell line, Lu-134-B cells, cultured in serum-supplemented medium and of cells transferred to and cultured in delipidized serum-supplemented (vitamin A-deficient) medium was studied. The cells cultured in serum-supplemented medium showed the phenotype of classic small cell lung cancer sensitive to radiation, while cells transferred to delipidized serum-supplemented medium showed partial squamous cell differentiation and became resistant to radiation. These results suggest that some small cell lung cancer cells in vitro change their morphology and radiosensitivity depending on the culture conditions. The change in radiosensitivity was reproducible, and was not reversible by culture of the radioresistant cells in delipidized serum-supplemented medium with addition of retinoic acid (vitamin A-sufficient medium) for two months, although squamous cells disappeared. Acquisition of radioresistancy was considered to occur as the result of clonal selective growth in delipidized medium of a minor cell population in the original cell culture, based on a study of chromosome number. It was also found that there was no association of myc-family oncogenes with the changes of radiosensitivity in this cell line. (author)

  17. Links between CD147 Function, Glycosylation, and Caveolin-1

    OpenAIRE

    Tang, Wei; Chang, Sharon B.; Hemler, Martin E.

    2004-01-01

    Cell surface CD147 shows remarkable variations in size (31-65 kDa) because of heterogeneous N-glycosylation, with the most highly glycosylated forms functioning to induce matrix metalloproteinase (MMP) production. Here we show that all three CD147 N-glycosylation sites make similar contributions to both high and low glycoforms (HG- and LG-CD147). l-Phytohemagglutinin lectin binding and swainsonine inhibition experiments indicated that HG-CD147 contains N-acetylglucosaminyltransferase V-cataly...

  18. Establishment and cell cycle distribution pattern of a radioresistant subline from human lung cancer D6 cell line

    International Nuclear Information System (INIS)

    Wei Qichun; Zheng Shu

    2003-01-01

    Objective: To establish a radioresistant cell subline from a human D6 lung cancer cell line and investigate the mechanism of radioresistance. Methods: D6 human NSCLC cells were exposed to X-rays generated by a linear accelerator(650 cGy per fraction). After a total exposure dose of 5200 cGy, a monoclone was obtained. The radiosensitivity and cell cycle distribution of this clone, together with its parent D6 cells, were measured by clonogenic assay and flow cytometry. Results: The new clone, namely D 6 -R subline, had a higher D 0 (D 0 =2.08 Gy) and a broader initial shoulder(Dq=1.64 Gy, N=2.20) than those of the parent D6 cell line (D 0 =1.84 Gy, Dq=0.34 Gy, N=1.20), being 1.65-fold increase in radioresistance as regards to the SF 2 . The D6-R subline also showed higher percentage of cells in S phase(53.4% vs 37.8%), but lower percentages in G 1 (44.1% vs 57.2%) and G 2 /M(2.5% vs 5%) phases. Conclusion: The new subline D6-R is more radioresistant as compare to its parent D6 cell line, and has a different cell cycle distribution

  19. The repair/repopulation effects ratio in the postirradiation recovery of hexaploid wheat varieties contrast by their radioresistance

    International Nuclear Information System (INIS)

    Selezneva, E.M.; Sarapul'tsev, B.I.

    1988-01-01

    The cytogenic and morphometrical distinctions between hexaploid wheat varieties contrast by their radioresistance during the postirradiation period are attributed to the differential activity of caffeine-dependent repair processes; they are not a reliable function of the rate of aberrant cell elimination

  20. Targeting DNA repair with PNKP inhibition sensitizes radioresistant prostate cancer cells to high LET radiation.

    Directory of Open Access Journals (Sweden)

    Pallavi Srivastava

    Full Text Available High linear energy transfer (LET radiation or heavy ion such as carbon ion radiation is used as a method for advanced radiotherapy in the treatment of cancer. It has many advantages over the conventional photon based radiotherapy using Co-60 gamma or high energy X-rays from a Linear Accelerator. However, charged particle therapy is very costly. One way to reduce the cost as well as irradiation effects on normal cells is to reduce the dose of radiation by enhancing the radiation sensitivity through the use of a radiomodulator. PNKP (polynucleotide kinase/phosphatase is an enzyme which plays important role in the non-homologous end joining (NHEJ DNA repair pathway. It is expected that inhibition of PNKP activity may enhance the efficacy of the charged particle irradiation in the radioresistant prostate cancer cell line PC-3. To test this hypothesis, we investigated cellular radiosensitivity by clonogenic cell survival assay in PC-3 cells.12Carbon ion beam of62 MeVenergy (equivalent 5.16 MeV/nucleon and with an entrance LET of 287 kev/μm was used for the present study. Apoptotic parameters such as nuclear fragmentation and caspase-3 activity were measured by DAPI staining, nuclear ladder assay and colorimetric caspase-3method. Cell cycle arrest was determined by FACS analysis. Cell death was enhanced when carbon ion irradiation is combined with PNKPi (PNKP inhibitor to treat cells as compared to that seen for PNKPi untreated cells. A low concentration (10μM of PNKPi effectively radiosensitized the PC-3 cells in terms of reduction of dose in achieving the same survival fraction. PC-3 cells underwent significant apoptosis and cell cycle arrest too was enhanced at G2/M phase when carbon ion irradiation was combined with PNKPi treatment. Our findings suggest that combined treatment of carbon ion irradiation and PNKP inhibition could enhance cellular radiosensitivity in a radioresistant prostate cancer cell line PC-3. The synergistic effect of PNKPi

  1. Dexamethasone-induced radioresistance occurring independent of human papilloma virus gene expression in cervical carcinoma cells

    Energy Technology Data Exchange (ETDEWEB)

    Rutz, H.P.; Mariotta, M.; Mirimanoff, R.O. [Lab. de Radiobiologie, Service de Radio-Oncologie, CHUV, Lausanne (Switzerland); Knebel Doeberitz, M. von [Deutsches Krebsforschungszentrum, Heidelberg (Germany). Inst. fuer Virusforschung

    1998-02-01

    The aim of this study was to investigate the role of HPV 18 E6 and E7 gene products with respect to radiosensitivity of two cervical carcinoma cell lines. The two cervical carcinoma lines C4-1 and SW 756 were used in which treatment with dexamethasone allows to modulate expression levels of HPV 18 E6 and E7 genes: Upregulation in C4-1, down-regulation in SW 756. Effects of treatment with dexamethasone on plating efficiency and radiosensitivity were assessed using a clonogenic assay. Treatment with dexamethasone increased plating efficiency of the C4-1 cells, but did not affect plating efficiency of SW 756 cells. Treatment with dexamethasone induced enhanced radioresistance in both cell lines. Thus, in C4-1 cells the observed changes in radioresistance correlate to the enhancement in expression of HPV 18 genes E6/E7, whereas in SW 756, a reduced expression correlates negatively with the enhanced radioresistance. (orig./MG) [Deutsch] Das Ziel dieser Studie lag darin, die Rolle der HPV-18-Gene E6 und E7 in bezug auf die Strahlenempfindlichkeit von menschlichen Zervixkarzinomzellen zu untersuchen. Wir verwendeten zwei menschliche Zervixkarzinomzellinien, C4-1 und SW 756, in welchen die Expression der viralen Gene HPV 18 E6 und E7 mit Dexamethason moduliert werden kann: In C4-1 bewirkt die Behandlung mit Dexamethason eine Erhoehung der Expression dieser Gene, in SW 756 eine Verminderung. Die Wirkung auf die Wachstumsfaehigkeit der Zellen und auf die Wachstumshemmung durch die Bestrahlung wurde unter Verwendung eines klonogenen Assays bestimmt. Dexamethason bewirkte eine erhoehte Wachstumsfaehigkeit der C4-1 Zellen, ohne die Wachstumsfaehigkeit der SW-756-Zellen zu beeinflussen, wie schon frueher beschrieben. Die Resistenz beider Zellinien gegenueber Bestrahlung wurde erhoeht. Somit besteht in den C4-1-Zellen eine Korrelation der Expression der viralen Gene mit der Zunahme der Strahlenresistenz, wogegen in den SW-756-Zellen die Abnahme der Expression im Gegensatz zu

  2. Radioresponsiveness at low doses. Hyper-radiosensitivity and increased radioresistance in mammalian cells

    International Nuclear Information System (INIS)

    Skov, K.A.

    1999-01-01

    The rationale for and importance of research on effects after radiation at 'low doses' are outlined. Such basic radiobiological studies on induction of repair enzymes, protective mechanisms, priming, and hypersensitivity are certainly all relevant to treatment of cancer (see Section 1, Studies at low doses - relevance to cancer treatment). Included are examples from many groups, using various endpoints to address the possibility of an induced resistance, which has been compared to the adaptive response [M.C. Joiner, P. Lambin, E.P. Malaise, T. Robson, J.E. Arrand, K.A. Skov, B. Marples, Hypersensitivity to very low single radiation doses: its relationship to the adaptive response and induced radioresistance, Mutat. Res. 358 (1996) 171-183.]. This is not intended to be an exhaustive review - rather a re-introduction of concepts such as priming and a short survey of molecular approaches to understanding induced resistance. New data on the response of HT29 cells after treatment (priming) with co-cultured activated neutrophils are included, with protection against X-rays (S1). Analysis of previously published results in various cells lines in terms of increased radioresistance (IRR)/intrinsic sensitivity are presented which complement a study on human tumour lines [P. Lambin, E.P. Malaise, M.C. Joiner, Might intrinsic radioresistance of human tumour cells be induced by radiation?, Int. Radiat. Biol. 69 (1996) 279-290]. It is not feasible to extrapolate to low doses from studies at high doses. The biological responses probably vary with dose, LET, and have variable time frames. The above approaches may lead to new types of treatment, or additional means to assess radioresponsiveness of tumours. Studies in many areas of biology would benefit from considerations of different dose regions, as the biological responses vary with dose. There may also be some implications in the fields of radiation protection and carcinogenesis, and the extensions of concepts of hyper

  3. Microbial radio-resistance of Salmonella Typhimurium in egg increases due to repetitive irradiation with electron beam

    International Nuclear Information System (INIS)

    Tesfai, Adiam T.; Beamer, Sarah K.; Matak, Kristen E.; Jaczynski, Jacek

    2011-01-01

    Ionizing radiation improves food safety. However, foodborne pathogens develop increased resistance in response to sub-lethal stresses such as heat, pH, antibiotics, etc. Therefore, it is hypothesized that foodborne pathogens may develop increased radio-resistance to electron beam (e-beam) radiation. The objective was to determine if D 10 -value for Salmonella Typhimurium in de-shelled raw egg (egg white and yolk mixed together) increases due to repetitive processing with e-beam at sub-lethal doses. Survivors were enumerated on non-selective (TSA) and selective (XLD) media. Survivors from the highest dose were isolated and used in subsequent e-beam cycle. This process was repeated four times for a total of five e-beam cycles. D 10 -values for S. Typhimurium enumerated on TSA and XLD following each e-beam cycle were calculated as inverse reciprocal of the slope of survivor curves. D 10 -values for the ATCC strain were 0.59±0.031 and 0.46±0.022 kGy on TSA and XLD, respectively. However, following the fifth e-beam cycle, the respective D 10 -values increased (P 0.05) to develop radio-resistance faster on selective media, likely due to facilitated selection of radio-resistant cells within microbial population following each e-beam cycle. For all five e-beam cycles, S. Typhimurium had higher (P 10 -values on non-selective media, indicating that sub-lethal injury followed by cellular repair and recovery are important for radio-resistance and inactivation of this microorganism. This study demonstrated that e-beam efficiently inactivates S. Typhimurium in raw egg; however, similar to other inactivation techniques and factors affecting microbial growth, S. Typhimurium develops increased radio-resistance if repetitively processed with e-beam at sub-lethal doses.

  4. Radioresistant DNA synthesis in fibroblasts of a patient with Down's syndrome

    International Nuclear Information System (INIS)

    Barenfel'd, L.S.; Bil'din, V.N.; Pleskach, N.M.; Prokof'eva, V.V.

    1985-01-01

    Ionizing radiation effect on DNA replication on fibroblasts of a healthy donor and a patient with Down's syndrome either by direct 3 H-thymidine inclusion into DNA, or by analysis of the sizes of daughter DNA moleculs at the state of stable distribution in acid saccharose, gradients was studied. Gamma-radiation doses (5-10 Gy) suppressing DNA synthesis in normal fibroblasts practically had no effect on DNA synthesisin fibroblasts of a patient with Down's syndrome. Radioresistant DNA synthesis in Down's syndrome is conditioned by a far less supression of replicon initiation as compared with the one in normal cells. So, it is stated that in Down's disease there is no delay in DNA synthesis by ionizing radiation that enables the normal cells to repair DNA damages before replication renewal

  5. Investigations on radiosensitive and radioresistant populations of Drosophila melanogaster. Pt. 10

    International Nuclear Information System (INIS)

    Noethel, H.

    1981-01-01

    In earlier work, immature oocytes of the irradiated population RoeI 4 of Drosophila melanogaster were found to be radioresistant relative to those of the basic population RoeI and to those of the control population Berlin wild (+K). The resistance of RoeI 4 relative to RoeI was previously attributed to a hypothetical 'factor' rar-3. In the present paper, evidence is presented to show that rar-3 is a single, recessive genetic factor, located on chromosome 3 at a map position of about 49.8. The action of rar-3 is apparently independent of that of rar-1 and rar-2, the factors already present in RoeI. (orig.)

  6. Metabolic analysis of radioresistant medulloblastoma stem-like clones and potential therapeutic targets.

    Directory of Open Access Journals (Sweden)

    Lue Sun

    Full Text Available Medulloblastoma is a fatal brain tumor in children, primarily due to the presence of treatment-resistant medulloblastoma stem cells. The energy metabolic pathway is a potential target of cancer therapy because it is often different between cancer cells and normal cells. However, the metabolic properties of medulloblastoma stem cells, and whether specific metabolic pathways are essential for sustaining their stem cell-like phenotype and radioresistance, remain unclear. We have established radioresistant medulloblastoma stem-like clones (rMSLCs by irradiation of the human medulloblastoma cell line ONS-76. Here, we assessed reactive oxygen species (ROS production, mitochondria function, oxygen consumption rate (OCR, energy state, and metabolites of glycolysis and tricarboxylic acid cycle in rMSLCs and parental cells. rMSLCs showed higher lactate production and lower oxygen consumption rate than parental cells. Additionally, rMSLCs had low mitochondria mass, low endogenous ROS production, and existed in a low-energy state. Treatment with the metabolic modifier dichloroacetate (DCA resulted in mitochondria dysfunction, glycolysis inhibition, elongated mitochondria morphology, and increased ROS production. DCA also increased radiosensitivity by suppression of the DNA repair capacity through nuclear oxidization and accelerated the generation of acetyl CoA to compensate for the lack of ATP. Moreover, treatment with DCA decreased cancer stem cell-like characters (e.g., CD133 positivity and sphere-forming ability in rMSLCs. Together, our findings provide insights into the specific metabolism of rMSLCs and illuminate potential metabolic targets that might be exploited for therapeutic benefit in medulloblastoma.

  7. Cyclophilin B Expression Is Associated with In Vitro Radioresistance and Clinical Outcome after Radiotherapy

    Directory of Open Access Journals (Sweden)

    Paul D. Williams

    2011-12-01

    Full Text Available The tools for predicting clinical outcome after radiotherapy are not yet optimal. To improve on this, we applied the COXEN informatics approach to in vitro radiation sensitivity data of transcriptionally profiled human cells and gene expression data from untreated head and neck squamous cell carcinoma (HNSCC and bladder tumors to generate a multigene predictive model that is independent of histologic findings and reports on tumor radiosensitivity. The predictive ability of this 41-gene model was evaluated in patients with HNSCC and was found to stratify clinical outcome after radiotherapy. In contrast, this model was not useful in stratifying similar patients not treated with radiation. This led us to hypothesize that expression of some of the 41 genes contributes to tumor radioresistance and clinical recurrence. Hence, we evaluated the expression the 41 genes as a function of in vitro radioresistance in the NCI-60 cancer cell line panel and found cyclophilin B (PPIB, a peptidylprolyl isomerase and target of cyclosporine A (CsA, had the strongest direct correlation. Functional inhibition of PPIB by small interfering RNA depletion or CsA treatment leads to radiosensitization in cancer cells and reduced cellular DNA repair. Immunohistochemical evaluation of PPIB expression in patients with HNSCC was found to be associated with outcome after radiotherapy. This work demonstrates that a novel 41-gene expression model of radiation sensitivity developed in bladder cancer cell lines and human skin fibroblasts predicts clinical outcome after radiotherapy in head and neck cancer patients and identifies PPIB as a potential target for clinical radiosensitization.

  8. Mechanism of derivation of radioresistance in HeLa cell population after repeated x-irradiation

    International Nuclear Information System (INIS)

    Kubo, Kihei; Koiwai, Soichiro; Morita, Kazuo

    1982-01-01

    The Radioresistant strain (X-8-5) was obtained from HeLa-SC population X-irradiated repeatedly for five times with 800 rad. The mean lethal dose (D 0 ) was 196 rad for X-8-5 cells, while it was 166 rad for control HeLa-SC cells. The fraction of cells containing an unusually long acrocentric chromosome (LA 2) exclusively increased with increasing number of irradiation of HeLa-SC population. A clonal strain with LA 2 marker was isolated from X-8-5 population and named RC-355. Since the RC-355 cells were more resistant (D 0 = 220 rad)than parental X-8-5 cells (D 0 = 196 rad), it was suggested that the cells with LA 2 were responsible for the radioresistance of X-8-5 population. The RC-355 cells were further subjected to the analysis of Q-banded karyotypes and it was observed that 18 types of specific markers (rm 1-17 and LA 2) were included in RC-355 cells in addition to 12 types of markers observed in most of HeLa-SC cells. Since the analysis of Q-banded karyotypes of RC-355 cells showed that RC-355 specific markers were not produced by radiation-induced rearrangements of HeLa-SC chromosomes, because twelve kinds of HeLa-SC markers were presented in RC-355 cells without any change, it was concluded that a small number of cells with LA 2 marker were originally presented in the control population and the relative fraction of them occupied increased after irradiation. (author)

  9. Association of anti-apoptotic Mcl-1L isoform expression with radioresistance of oral squamous carcinoma cells

    International Nuclear Information System (INIS)

    Palve, Vinayak C; Teni, Tanuja R

    2012-01-01

    Oral cancer is a common cancer and a major health problem in the Indian subcontinent. At our laboratory Mcl-1, an anti-apoptotic member of the Bcl-2 family has been demonstrated to be overexpressed in oral cancers and to predict outcome in oral cancer patients treated with definitive radiotherapy. To study the role of Mcl-1 isoforms in radiation response of oral squamous carcinoma cells (OSCC), we investigated in the present study, the association of Mcl-1 isoform expression with radiosensitivity of OSCC, using siRNA strategy. The time course expression of Mcl-1 splice variants (Mcl-1L, Mcl-1S & Mcl-1ES) was studied by RT-PCR, western blotting & immunofluorescence, post-irradiation in oral cell lines [immortalized FBM (radiosensitive) and tongue cancer AW8507 & AW13516 (radioresistant)]of relatively differing radiosensitivities. The effect of Mcl-1L knockdown alone or in combination with ionizing radiation (IR) on cell proliferation, apoptosis & clonogenic survival, was investigated in AW8507 & AW13516 cells. Further the expression of Mcl-1L protein was assessed in radioresistant sublines generated by fractionated ionizing radiation (FIR). Three to six fold higher expression of anti-apoptotic Mcl-1L versus pro-apoptotic Mcl-1S was observed at mRNA & protein levels in all cell lines, post-irradiation. Sustained high levels of Mcl-1L, downregulation of pro-apoptotic Bax & Bak and a significant (P < 0.05) reduction in apoptosis was observed in the more radioresistant AW8507, AW13516 versus FBM cells, post-IR. The ratios of anti to pro-apoptotic proteins were high in AW8507 as compared to FBM. Treatment with Mcl-1L siRNA alone or in combination with IR significantly (P < 0.01) increased apoptosis viz. 17.3% (IR), 25.3% (siRNA) and 46.3% (IR plus siRNA) and upregulated pro-apoptotic Bax levels in AW8507 cells. Combination of siRNA & IR treatment significantly (P < 0.05) reduced cell proliferation and clonogenic survival of radioresistant AW8507 & AW13516 cells

  10. Genome-wide analyses of long noncoding RNA expression profiles correlated with radioresistance in nasopharyngeal carcinoma via next-generation deep sequencing.

    Science.gov (United States)

    Li, Guo; Liu, Yong; Liu, Chao; Su, Zhongwu; Ren, Shuling; Wang, Yunyun; Deng, Tengbo; Huang, Donghai; Tian, Yongquan; Qiu, Yuanzheng

    2016-09-06

    Radioresistance is one of the major factors limiting the therapeutic efficacy and prognosis of patients with nasopharyngeal carcinoma (NPC). Accumulating evidence has suggested that aberrant expression of long noncoding RNAs (lncRNAs) contributes to cancer progression. Therefore, here we identified lncRNAs associated with radioresistance in NPC. The differential expression profiles of lncRNAs associated with NPC radioresistance were constructed by next-generation deep sequencing by comparing radioresistant NPC cells with their parental cells. LncRNA-related mRNAs were predicted and analyzed using bioinformatics algorithms compared with the mRNA profiles related to radioresistance obtained in our previous study. Several lncRNAs and associated mRNAs were validated in established NPC radioresistant cell models and NPC tissues. By comparison between radioresistant CNE-2-Rs and parental CNE-2 cells by next-generation deep sequencing, a total of 781 known lncRNAs and 2054 novel lncRNAs were annotated. The top five upregulated and downregulated known/novel lncRNAs were detected using quantitative real-time reverse transcription-polymerase chain reaction, and 7/10 known lncRNAs and 3/10 novel lncRNAs were demonstrated to have significant differential expression trends that were the same as those predicted by deep sequencing. From the prediction process, 13 pairs of lncRNAs and their associated genes were acquired, and the prediction trends of three pairs were validated in both radioresistant CNE-2-Rs and 6-10B-Rs cell lines, including lncRNA n373932 and SLITRK5, n409627 and PRSS12, and n386034 and RIMKLB. LncRNA n373932 and its related SLITRK5 showed dramatic expression changes in post-irradiation radioresistant cells and a negative expression correlation in NPC tissues (R = -0.595, p < 0.05). Our study provides an overview of the expression profiles of radioresistant lncRNAs and potentially related mRNAs, which will facilitate future investigations into the

  11. Microarray analysis of DNA damage repair gene expression profiles in cervical cancer cells radioresistant to 252Cf neutron and X-rays

    International Nuclear Information System (INIS)

    Qing, Yi; Wang, Ge; Wang, Dong; Yang, Xue-Qin; Zhong, Zhao-Yang; Lei, Xin; Xie, Jia-Yin; Li, Meng-Xia; Xiang, De-Bing; Li, Zeng-Peng; Yang, Zhen-Zhou

    2010-01-01

    The aim of the study was to obtain stable radioresistant sub-lines from the human cervical cancer cell line HeLa by prolonged exposure to 252 Cf neutron and X-rays. Radioresistance mechanisms were investigated in the resulting cells using microarray analysis of DNA damage repair genes. HeLa cells were treated with fractionated 252 Cf neutron and X-rays, with a cumulative dose of 75 Gy each, over 8 months, yielding the sub-lines HeLaNR and HeLaXR. Radioresistant characteristics were detected by clone formation assay, ultrastructural observations, cell doubling time, cell cycle distribution, and apoptosis assay. Gene expression patterns of the radioresistant sub-lines were studied through microarray analysis and verified by Western blotting and real-time PCR. The radioresistant sub-lines HeLaNR and HeLaXR were more radioresisitant to 252 Cf neutron and X-rays than parental HeLa cells by detecting their radioresistant characteristics, respectively. Compared to HeLa cells, the expression of 24 genes was significantly altered by at least 2-fold in HeLaNR cells. Of these, 19 genes were up-regulated and 5 down-regulated. In HeLaXR cells, 41 genes were significantly altered by at least 2-fold; 38 genes were up-regulated and 3 down-regulated. Chronic exposure of cells to ionizing radiation induces adaptive responses that enhance tolerance of ionizing radiation and allow investigations of cellular radioresistance mechanisms. The insights gained into the molecular mechanisms activated by these 'radioresistance' genes will lead to new therapeutic targets for cervical cancer

  12. β‑catenin nuclear translocation induced by HIF‑1α overexpression leads to the radioresistance of prostate cancer.

    Science.gov (United States)

    Luo, Yong; Li, Mingchuan; Zuo, Xuemei; Basourakos, Spyridon P; Zhang, Jiao; Zhao, Jiahui; Han, Yili; Lin, Yunhua; Wang, Yongxing; Jiang, Yongguang; Lan, Ling

    2018-04-12

    Hypoxia-inducible factor‑1α (HIF‑1α) is known to play crucial roles in tumor radioresistance; however, the molecular mechanisms responsible for the promotion of tumor radioresistance by HIF‑1α remain unclear. β‑catenin is known to be involved in the metastatic potential of prostate cancer (PCa). In this study, to investigate the role of HIF‑1α and β‑catenin in the radioresistance of PCa, two PCa cell lines, LNCaP and C4‑2B, were grouped as follows: Negative control (no treatment), HIF‑1α overexpression group (transfected with HIF‑1α overexpression plasmid) and β‑catenin silenced group (transfected with HIF‑1α plasmids and β‑catenin-shRNA). Cell proliferation, cell cycle, cell invasion and radiosensitivity were examined under normal or hypoxic conditions. In addition, radiosensitivity was examined in two mouse PCa models (the LNCaP orthotopic BALB/c-nu mice model and the C4‑2B subcutaneous SCID mice model). Our results revealed that in both the LNCaP and C4‑2B cells, transfection with HIF‑1α overexpression plasmid led to an enhanced β‑catenin nuclear translocation, while β‑catenin silencing inhibited β‑catenin nuclear translocation. The enhanced β‑catenin nuclear translocation induced by HIF‑1α overexpression resulted in an enhanced cell proliferation and cell invasion, an altered cell cycle distribution, decreased apoptosis, and improved non‑homologous end joining (NHEJ) repair under normal and irradiation conditions. Similar results were observed in the animal models. HIF‑1α overexpression enhanced β‑catenin nuclear translocation, which led to the activation of the β‑catenin/NHEJ signaling pathway and increased cell proliferation, cell invasion and DNA repair. These results thus suggest that HIF‑1α overexpression promotes the radioresistance of PCa cells.

  13. A comparative study of radioresistance of rare and non-disappearing species of tulipal from the flora of Azerbaijan

    International Nuclear Information System (INIS)

    Ibadov, O.V.; Askerov, I.T.; Medzhidov, M.M.; Alekperov, U.K.

    1983-01-01

    Eichle and Sclimid bulds irradiated by gamma-rays of different doses (1-1 Gy) have been investigated. Morphological and phenological observations are carried out, decorative propertie the tested plants are estimated. It is found that low radiation doses (1-5 Gy) stimulate the sprouting of these species, while high doses suppress it. The Eichler species being somewhat more radioresistant than those of Schmi type

  14. In vitro stemness characterization of radio-resistant clones isolated from a medulloblastoma cell line ONS-76

    International Nuclear Information System (INIS)

    Sun, Lue; Suzuki, Kenshi; Gerelchuluun, Ariungerel; Hong, Zhengshan; Moritake, Takashi; Zenkoh, Junko; Tsuboi, Koji; Zheng, Yun-Wen; Taniguchi, Hideki

    2013-01-01

    One-third of patients with medulloblastoma die due to recurrence after various treatments including radiotherapy. Although it has been postulated that cancer stem-like cells are radio-resistant and play an important role in tumor recurrence, the 'stemness' of medulloblastoma cells surviving irradiation has not yet been elucidated. Using a medulloblastoma cell line ONS-76, cells that survived gamma irradiation were investigated on their 'stemness' in vitro. From 10 500 cells, 20 radio-resistant clones were selected after gamma ray irradiation (5 Gy x two fractions) using the replica micro-well technique. These 20 resistant clones were screened for CD133 positivity by flow cytometry followed by side population assay, tumor sphere formation assay and clonogenic survival assay. Results revealed CD133 fractions were significantly elevated in three clones, which also exhibited significantly increased levels of tumor sphere formation ability and side population fraction. Clonogenic survival assay demonstrated that their radio-resistance was significantly higher than the parental ONS-76. This may support the hypothesis that a small number of cancer stem-like cells (CSCs) are the main culprits in local recurrence after radiotherapy, and disruption of the resistance mechanism of these CSCs is a critical future issue in improving the outcome of patients with medulloblastoma. (author)

  15. Novel pattern of post-γ ray de novo DNA synthesis in a radioresistant human strain

    International Nuclear Information System (INIS)

    Mirzayans, R.; Gentner, N.E.; Paterson, M.C.

    1985-01-01

    Enhanced resistance to radiation cytotoxicity in a fibroblast strain from an afflicted member of a Li-Fraumeni syndrome family may be largely ascribable to a change in the pattern of DNA replicative synthesis following γ ray exposure. That is, the extent of the initial radiogenic inhibition of replicative synthesis and the time interval before its subsequent recovery were both found to be greater in radioresistant (RR) compared to normal cells. In addition, the post-recovery replication rates in the RR cells were both higher and longer lasting than those in the control cells. A similar differential pattern was also seen following treatment with 4NQO, another DNA-damaging agent to which this RR strain displays enhanced resistance. Moreover, several conventional DNA repair assays indicated that the RR cells repair radiogenic damage at normal rates. The authors therefore suggest that the increased inhibition and prolonged lag in resumption of replicative synthesis seen in the RR strain upon exposure to certain genotoxic agents may enhance cellular recovery by ''buying additional time'' for processing of potentially lethal lesions

  16. Effect of individual and group housing of mice on the level of radioresistance

    Directory of Open Access Journals (Sweden)

    Dorozhkina O.V.

    2015-12-01

    Full Text Available Aim: to examine the effect of individual and group housing of mice on radioresistance. Material and methods. Effects of individual and group housing of mice on immunity and blood systems were studied on ICR (CD-1 and C57BI6 male mice before and after proton irradiation. Results. Group housing of intact animals resulted in a decline in the number of nucleated cells in the femur bone marrow and thymus mass. The irradiation with proton with energy of 171 MeV at a dose of 1 Gy causes a statistically significant greater reduction of the number of nucleated cells in the femur bone marrow in group-housed mice. A trend toward greater safety of the number of leukocytes in the peripheral blood and higher proliferative activity of bone marrow cells, as well as lower level of aberrant mitoses have been noted in individually-housed mice. Reduction processes in the recovery period of radiation sickness take place at a greater rate in group-housed mice. Conclusion. Group housing of male mice causes increased sensitivity of the blood and immunity systems to the effects of radiation and at the same time accelerates processes of radiation recovery.

  17. Radioresistance of intermediate TCR cells and their localization in the body of mice revealed by irradiation

    International Nuclear Information System (INIS)

    Kimura, Motohiko; Watanabe, Hisami; Ohtsuka, Kazuo; Iiai, Tsuneo; Tsuchida, Masanori; Sato, Shotaro; Abo, Toru

    1993-01-01

    Extrathymic generation of T cells in the liver and in the intestine was recently demonstrated. We investigated herein whether such T cells, especially those in the liver, are present in other organs of mice. This investigation is possible employing our recently introduced method with which even a minor proportion of extrathymic, intermediate T-cell receptor (TCR) cells in organs other than the liver can be identified. Intermediate TCR cells expressed higher levels of IL-2Rβ and lymphocyte function-associated antigen-1 (LFA-1) than bright TCR cells (i.e., T cells of thymic origin) as revealed by two-color staining. Although intermediate TCR cells were present at a small proportion in the spleen and thymus, they predominated in these organs after irradiation (9 Gy) and bone marrow reconstitution, or after low dose irradiation (6 Gy). This was due to that intermediate TCR cells were relatively radioresistant, whereas bright TCR cells were radiosensitive. Microscopic observation and immunochemical staining showed that intermediate TCR cells in the spleen localized in the red pulp and those in the thymus localized in the medulla. These intermediate TCR cells displayed a large light scatter, similar to such cells in the liver. The present results suggest that intermediate TCR cells may proliferate at multiple sites in the body. (author)

  18. Alterations in transcription factor binding in radioresistant human melanoma cells after ionizing radiation

    International Nuclear Information System (INIS)

    Sahijdak, W.M.; Yang, Chin-Rang; Zuckerman, J.S.; Meyers, M.; Boothman, D.A.

    1994-01-01

    We analyzed alterations in transcription factor binding to specific, known promoter DNA consensus sequences between irradiated and unirradiated radioresistant human melanoma (U1-Mel) cells. The goal of this study was to begin to investigate which transcription factors and DNA-binding sites are responsible for the induction of specific transcripts and proteins after ionizing radiation. Transcription factor binding was observed using DNA band-shift assays and oligonucleotide competition analyses. Confluence-arrested U1-Mel cells were irradiated (4.5 Gy) and harvested at 4 h. Double-stranded oligonucleotides containing known DNA-binding consensus sites for specific transcription factors were used. Increased DNA binding activity after ionizing radiation was noted with oligonucleotides containing the CREB, NF-kB and Sp1 consensus sites. No changes in protein binding to AP-1, AP-2, AP-3, or CTF/NF1, GRE or Oct-1 consensus sequences were noted. X-ray activation of select transcription factors, which bind certain consensus sites in promoters, may cause specific induction or repression of gene transcription. 22 refs., 2 figs

  19. Bimodal cell death induced by high radiation doses in the radioresistant sf9 insect cell line

    International Nuclear Information System (INIS)

    Chandna, S.

    2003-01-01

    Full text: This study was conducted to investigate the mode(s) of cell death induced by high radiation doses in the highly radioresistant Sf9 insect ovarian cell line. Methods: Cells were exposed to γ-radiation doses 200Gy and 500Gy, harvested at various time intervals (6h-72h) following irradiation, and subjected to cell morphology assay, DNA agarose gel electrophoresis, single cell gel electrophoresis (SCGE; comet assay) and Annexin-V labeling for the detection of membrane phosphatidylserine externalization. Cell morphology was assessed in cells entrapped and fixed in agarose gel directly from the cell suspension, thus preventing the possible loss of fragments/ apoptotic bodies. Surviving fraction of Sf9 cells was 0.01 at 200Gy and 98%) undergoing extensive DNA fragmentation at 500Gy, whereas the frequency of cells with DNA fragmentation was considerably less (∼12%) at 200Gy. Conclusions: While the mode of cell death at 200Gy seems to be different from typical apoptosis, a dose of 500Gy induced bimodal cell death, with typical apoptotic as well as the atypical cell death observed at 200Gy

  20. Evidence for induced radioresistance from survival and other end points: An introduction

    International Nuclear Information System (INIS)

    Joiner, M.C.

    1994-01-01

    A substantial body of data published during the past 30 years makes a strong case for the existence of cellular radioprotective mechanisms that can be up-regulated in response to exposure to small doses of ionizing radiation. Either these open-quotes inducedclose quotes mechanisms can protect against a subsequent exposure to radiation that may be substantially larger than the initial open-quotes primingclose quotes or open-quotes conditioningclose quotes dose, or they may influence the shape of the survival response to single doses so that small radiation exposures are more effective per unit dose than larger exposures above a threshold where the induced radioprotection is triggered. Evidence for these effects comes from studies in vitro with protozoa, algae, higher plant cells, insect cells, mammalian and human cells, and studies on animal models in vivo. Work at the molecular level is now confirming that changes in levels of some cytoplasmic and nuclear proteins, and the increased expression of some genes, may occur within a few hours or even minutes of irradiation. This would be sufficiently quick to explain the phenomenon of induced radioresistance although the precise mechanism, whether by repair, cell cycle control or some other process, remains yet undefined. 35 refs

  1. Radioresistance of populations of bank voles Clethrionomys glareolus in radionuclide-contaminated areas

    International Nuclear Information System (INIS)

    Il'enko, A.I.; Krapivko, T.P.

    1994-01-01

    Contamination of extended territories with radionuclides renders the monitoring of natural populations in their habitats an important work to be done in order to determine the directions of evolution caused by long-term exposure to ionizing radiation. In view of this, many years of field and experimental radioecological studies were devoted to animal populations that inhabit the territories contaminated with 137 Cs after the Chernobyl Power Plant disaster. Special emphasis was placed on the investigation of the time course of radiosensitivity of mammalian populations over several generations as a general index of adaptive processes developing in an area with an elevated radiation background. The authors monitored the population of the European bank vole, a species known for its high spontaneous resistance to radiation. In optimal environmental conditions, it has LD 50/30 = 9.7 Gy. The reaction of bank vole populations to radioactive contamination of their environment primarily increases the rate of variation of sensitivity to ionizing radiation. This results in a continuous increase in the radioresistance of the populations to a certains table level. The findings suggest that adaptive processes occur in natural mammalian populations subjected to chronic ionizing irradiation

  2. Microbial radio-resistance of Salmonella Typhimurium in egg increases due to repetitive irradiation with electron beam

    Energy Technology Data Exchange (ETDEWEB)

    Tesfai, Adiam T.; Beamer, Sarah K.; Matak, Kristen E. [West Virginia University, Division of Animal and Nutritional Sciences, PO Box 6108, Morgantown, WV 26508 (United States); Jaczynski, Jacek, E-mail: Jacek.Jaczynski@mail.wvu.ed [West Virginia University, Division of Animal and Nutritional Sciences, PO Box 6108, Morgantown, WV 26508 (United States)

    2011-04-15

    Ionizing radiation improves food safety. However, foodborne pathogens develop increased resistance in response to sub-lethal stresses such as heat, pH, antibiotics, etc. Therefore, it is hypothesized that foodborne pathogens may develop increased radio-resistance to electron beam (e-beam) radiation. The objective was to determine if D{sub 10}-value for Salmonella Typhimurium in de-shelled raw egg (egg white and yolk mixed together) increases due to repetitive processing with e-beam at sub-lethal doses. Survivors were enumerated on non-selective (TSA) and selective (XLD) media. Survivors from the highest dose were isolated and used in subsequent e-beam cycle. This process was repeated four times for a total of five e-beam cycles. D{sub 10}-values for S. Typhimurium enumerated on TSA and XLD following each e-beam cycle were calculated as inverse reciprocal of the slope of survivor curves. D{sub 10}-values for the ATCC strain were 0.59{+-}0.031 and 0.46{+-}0.022 kGy on TSA and XLD, respectively. However, following the fifth e-beam cycle, the respective D{sub 10}-values increased (P<0.05) to 0.69{+-}0.026 and 0.61{+-}0.029 kGy, respectively. S. Typhimurium showed a trend (P>0.05) to develop radio-resistance faster on selective media, likely due to facilitated selection of radio-resistant cells within microbial population following each e-beam cycle. For all five e-beam cycles, S. Typhimurium had higher (P<0.05) D{sub 10}-values on non-selective media, indicating that sub-lethal injury followed by cellular repair and recovery are important for radio-resistance and inactivation of this microorganism. This study demonstrated that e-beam efficiently inactivates S. Typhimurium in raw egg; however, similar to other inactivation techniques and factors affecting microbial growth, S. Typhimurium develops increased radio-resistance if repetitively processed with e-beam at sub-lethal doses.

  3. Redox-Mediated and Ionizing-Radiation-Induced Inflammatory Mediators in Prostate Cancer Development and Treatment

    Science.gov (United States)

    Miao, Lu; Holley, Aaron K.; Zhao, Yanming; St. Clair, William H.

    2014-01-01

    Abstract Significance: Radiation therapy is widely used for treatment of prostate cancer. Radiation can directly damage biologically important molecules; however, most effects of radiation-mediated cell killing are derived from the generated free radicals that alter cellular redox status. Multiple proinflammatory mediators can also influence redox status in irradiated cells and the surrounding microenvironment, thereby affecting prostate cancer progression and radiotherapy efficiency. Recent Advances: Ionizing radiation (IR)–generated oxidative stress can regulate and be regulated by the production of proinflammatory mediators. Depending on the type and stage of the prostate cancer cells, these proinflammatory mediators may lead to different biological consequences ranging from cell death to development of radioresistance. Critical Issues: Tumors are heterogeneous and dynamic communication occurs between stromal and prostate cancer cells, and complicated redox-regulated mechanisms exist in the tumor microenvironment. Thus, antioxidant and anti-inflammatory strategies should be carefully evaluated for each patient at different stages of the disease to maximize therapeutic benefits while minimizing unintended side effects. Future Directions: Compared with normal cells, tumor cells are usually under higher oxidative stress and secrete more proinflammatory mediators. Thus, redox status is often less adaptive in tumor cells than in their normal counterparts. This difference can be exploited in a search for new cancer therapeutics and treatment regimes that selectively activate cell death pathways in tumor cells with minimal unintended consequences in terms of chemo- and radio-resistance in tumor cells and toxicity in normal tissues. Antioxid. Redox Signal. 20, 1481–1500. PMID:24093432

  4. Possible association between stem-like hallmark and radioresistance in human cervical carcinoma cells.

    Science.gov (United States)

    Kumazawa, Shoko; Kajiyama, Hiroaki; Umezu, Tomokazu; Mizuno, Mika; Suzuki, Shiro; Yamamoto, Eiko; Mitsui, Hiroko; Sekiya, Ryuichiro; Shibata, Kiyosumi; Kikkawa, Fumitaka

    2014-05-01

    We aimed to investigate the possibility of an association between a stem-like hallmark and radiotherapeutic sensitivity in human cervical carcinoma cells. Side-population (SP) cells and non-SP (NSP) cells in HeLa cells were isolated using flow cytometry and Hoechst 33342 efflux. We performed Western blot analysis to evaluate the expression of stem cell markers (CXCR4, Oct3/4, CD133, and SOX2) and apoptosis markers after irradiation. In addition, SP and NSP cells were injected into nude mice and we assessed subcutaneous tumor formation. To examine tolerance of irradiation, colony formation and apoptosis change were confirmed in the SP and NSP cells. SP cells showed a higher expression of CXCR4, Oct3/4, CD133, and SOX2 than NSP cells. The colony size of SP cells cultured on non-coated dishes was larger than that of NSP cells, and NSP cells were easily induced to undergo apoptosis. SP cells tended to form spheroids and showed a higher level of tumorigenicity compared with NSP cells. In addition, nude mice inoculated with SP cells showed greater tumor growth compared with NSP cells. SP cells showed a higher tumorigenicity and lower apoptotic potential, leading to enhanced radiotolerance. Tumor SP cells showed higher-level stem-cell-like characters and radioresistance than NSP cells. SP cells may be useful for new therapeutic approaches for radiation-resistant cervical cancer. © 2014 The Authors. Journal of Obstetrics and Gynaecology Research © 2014 Japan Society of Obstetrics and Gynecology.

  5. Bcl-2 inhibitors potentiate the cytotoxic effects of radiation in Bcl-2 overexpressing radioresistant tumor cells

    International Nuclear Information System (INIS)

    Hara, Takamitsu; Omura-Minamisawa, Motoko; Chao Cheng; Nakagami, Yoshihiro; Ito, Megumi; Inoue, Tomio

    2005-01-01

    Purpose: Bcl-2, an inhibitor of apoptosis frequently shows elevated expression in human tumors, thus resulting in resistance to radiation therapy. Therefore, inhibiting Bcl-2 function may enhance the radiosensitivity of tumor cells. Tetrocarcin A (TC-A) and bcl-2 antisense oligonucleotides exhibit antitumor activity by inhibiting Bcl-2 function and transcription, respectively. We investigated whether these antitumor agents would enhance the cytotoxic effects of radiation in tumor cells overexpressing Bcl-2. Methods and materials: We used HeLa/bcl-2 cells, a stable Bcl-2-expressing cell line derived from wild-type HeLa (HeLa/wt) cells. Cells were incubated with TC-A and bcl-2 antisense oligonucleotides for 24 h after irradiation, and cell viability was then determined. Apoptotic cells were quantified by flow cytometric assay. Results: The HeLa/bcl-2 cells were more resistant to radiation than HeLa/wt cells. At concentrations that are not inherently cytotoxic, both TC-A and bcl-2 antisense oligonucleotides increased the cytotoxic effects of radiation in HeLa/bcl-2 cells, but not in HeLa/wt cells. However, in HeLa/bcl-2 cells, additional treatment with TC-A in combination with radiation did not significantly increase apoptosis. Conclusions: The present results suggest that TC-A and bcl-2 antisense oligonucleotides reduce radioresistance of tumor cells overexpressing Bcl-2. Therefore, a combination of radiotherapy and Bcl-2 inhibitors may prove to be a useful therapeutic approach for treating tumors that overexpress Bcl-2

  6. Critical analysis of salvage radical prostatectomy in the management of radioresistant prostate cancer

    Energy Technology Data Exchange (ETDEWEB)

    Seabra, Daniel; Faria, Eliney; Dauster, Breno; Rodrigues, Gunther; Fava, Gilberto [Pio XII Foundation, Barretos, SP (Brazil). Section of Urology], e-mail: daniel.seabra@terra.com.br

    2009-01-15

    Purpose: To critically evaluate salvage radical prostatectomy (SRP) in the treatment of patients with recurrent prostate cancer (PCa). Materials and Methods: From January 2005 to June 2007, we assessed patients with recurrent localized PCa. Recurrence was suspected when there were three or more successive increases in prostate specific antigen (PSA) after nadir. After the routine imagery examinations, and once localized PCa was confirmed, patients were offered SRP. Following surgery, we evaluated bleeding, rectal injury, urinary incontinence or obstruction and impotence. PSA values were measured at 1, 3, 6, months and thereafter twice a year. Results: Forty-two patients underwent SRP. The average age was 61 years. Following radiotherapy , the mean PSA nadir was 1.5 ng/mL (0.57-5.5). The mean prostate specific antigen doubling time (PSA-DT) was 14 months (6-20). Prior to SRP, the mean PSA was 5.7 ng/mL (2.9-18). The pathologic staging was pT2a: 13%; pT2b: 34%; pT2c: 27%; pT3a: 13%; and pT3b: 13%. Bleeding > 600 mL occurred in 14% of the cases; urethral stenosis in 50%; and urinary incontinence (two or more pads/day) in 72%. The mean follow-up post-SRP ranged from 6 to 30 months. The PSA level rose in 9, of which 6 had PSA-DT < 10 months. Conclusions: SRP is a feasible method in the management of localized radioresistant PCa. PSA-DT has shown to be important for the selection and SRP should not be performed if PSA-DT > 10 months. Due to its increased morbidity, SRP should be only offered to the patients who are more concerned about survival rather than quality of life. (author)

  7. Effects of radiation type and delivery mode on a radioresistant eukaryote Cryptococcus neoformans

    International Nuclear Information System (INIS)

    Shuryak, Igor; Bryan, Ruth A.; Broitman, Jack; Marino, Stephen A.; Morgenstern, Alfred; Apostolidis, Christos; Dadachova, Ekaterina

    2015-01-01

    Introduction: Most research on radioresistant fungi, particularly on human pathogens such as Cryptococcus neoformans, involves sparsely-ionizing radiation. Consequently, fungal responses to densely-ionizing radiation, which can be harnessed to treat life-threatening fungal infections, remain incompletely understood. Methods: We addressed this issue by quantifying and comparing the effects of densely-ionizing α-particles (delivered either by external beam or by 213 Bi-labeled monoclonal antibodies), and sparsely-ionizing 137 Cs γ-rays, on Cryptococus neoformans. Results: The best-fit linear-quadratic parameters for clonogenic survival were the following: α = 0.24 × 10 −2 Gy −1 for γ-rays and 1.07 × 10 −2 Gy −1 for external-beam α-particles, and β = 1.44 × 10 −5 Gy −2 for both radiation types. Fungal cell killing by radiolabeled antibodies was consistent with predictions based on the α-particle dose to the cell nucleus and the linear-quadratic parameters for external-beam α-particles. The estimated RBE (for α-particles vs. γ-rays) at low doses was 4.47 for the initial portion of the α-particle track, and 7.66 for the Bragg peak. Non-radiological antibody effects accounted for up to 23% of cell death. Conclusions: These results quantify the degree of C. neoformans resistance to densely-ionizing radiations, and show how this resistance can be overcome with fungus-specific radiolabeled antibodies

  8. Radioresistance of aboriginal earthworms of Absheron peninsula in radioactive model systems

    International Nuclear Information System (INIS)

    Suleymanova, A.S.; Garibov, A.A.; Abdullayev, A.A.; Naghiyev, J.A.; Farajov, M.F.; Samedov, P.A.

    2011-01-01

    Full tex:Soil animals are the most suitable biological indicators of radioactive pollution because they are parts of nutritional chains and webs, occur in relatively high numbers and can be collected during most parts of the year.The use of earthworms in the soils from Ramana iodine plant area of Absheron peninsula, which is rich with radionuclide and in the soil mixed with RaCl2 and UO2SO4 salt solutions in different concentrations, for resistance to ionizing radiation in soil is reviewed.Effect of radionuclides on vital functions of earthworms and determination of radionuclides (before and after experiments) in contaminated soils by ?-spectrometer were carried out in laboratory condition during a month. Regarding to ?-spectrometric results there were determined that earthworms had absorbed most of radioactive elements and allocated them as coprogenous substances on the upper layer of soil. In Ramana soils mostly the 238U radionuclides were highly accumulated in gut cells of the earthworms. By the influence of radioactive elements it was shown that the earthworms from Ramana iodine plant territory variants had proved particularly sensitive to an increased Ra-radiation background and to iodine factor.It was interestingly established the proportional dependence between rising level of accumulation in earthworms' body and in their coprolites and increasing of radioactive salts containing in the soils treated by UO2SO4 and RaCl2 solutions.Thus there is different level of radioresistance for earthworms and they are among the best bioindicators of polluted soils. There was an obvious perspective of using of earthworms as bioremediators in polluted soil with radionuclides in future as well.

  9. Vive la radiorésistance!: converging research in radiobiology and biogerontology to enhance human radioresistance for deep space exploration and colonization

    Science.gov (United States)

    Cortese, Franco; Klokov, Dmitry; Osipov, Andreyan; Stefaniak, Jakub; Moskalev, Alexey; Schastnaya, Jane; Cantor, Charles; Aliper, Alexander; Mamoshina, Polina; Ushakov, Igor; Sapetsky, Alex; Vanhaelen, Quentin; Alchinova, Irina; Karganov, Mikhail; Kovalchuk, Olga; Wilkins, Ruth; Shtemberg, Andrey; Moreels, Marjan; Baatout, Sarah; Izumchenko, Evgeny; de Magalhães, João Pedro; Artemov, Artem V.; Costes, Sylvain V.; Beheshti, Afshin; Mao, Xiao Wen; Pecaut, Michael J.; Kaminskiy, Dmitry; Ozerov, Ivan V.; Scheibye-Knudsen, Morten; Zhavoronkov, Alex

    2018-01-01

    While many efforts have been made to pave the way toward human space colonization, little consideration has been given to the methods of protecting spacefarers against harsh cosmic and local radioactive environments and the high costs associated with protection from the deleterious physiological effects of exposure to high-Linear energy transfer (high-LET) radiation. Herein, we lay the foundations of a roadmap toward enhancing human radioresistance for the purposes of deep space colonization and exploration. We outline future research directions toward the goal of enhancing human radioresistance, including upregulation of endogenous repair and radioprotective mechanisms, possible leeways into gene therapy in order to enhance radioresistance via the translation of exogenous and engineered DNA repair and radioprotective mechanisms, the substitution of organic molecules with fortified isoforms, and methods of slowing metabolic activity while preserving cognitive function. We conclude by presenting the known associations between radioresistance and longevity, and articulating the position that enhancing human radioresistance is likely to extend the healthspan of human spacefarers as well. PMID:29581875

  10. Proteomic profiling identifies PTK2/FAK as a driver of radioresistance in HPV-negative head and neck cancer

    Science.gov (United States)

    Skinner, Heath D.; Giri, Uma; Yang, Liang P.; Woo, Sang Hyeok; Story, Michael; Pickering, Curtis; Byers, Lauren; Williams, Michelle; El Naggar, Adel; Wang, Jing; Diao, Lixia; Shen, Li; Fan, You Hong; Molkentine, David; Beadle, Beth; Meyn, Raymond; Myers, Jeffrey; Heymach, John

    2016-01-01

    Purpose Head and neck squamous cell carcinoma (HNSCC) is commonly treated with radiotherapy, and local failure after treatment remains the major cause of disease-related mortality. To date human papillomavirus (HPV) is the only known clinically validated, targetable biomarkers of response to radiation in HNSCC. Experimental Design We performed proteomic and transcriptomic analysis of targetable biomarkers of radioresistance in HPV-negative HNSCC cell lines in vitro, and tested whether pharmacologic blockade of candidate biomarkers sensitized cells to radiotherapy. Candidate biomarkers were then investigated in several independent cohorts of patients with HNSCC. Results Increased expression of several targets was associated with radioresistance, including FGFR, ERK1, EGFR, and focal adhesion kinase (FAK), also known as PTK2. Chemical inhibition of PTK2/FAK, but not FGFR, led to significant radiosensitization with increased G2/M arrest and potentiated DNA damage. PTK2/FAK overexpression was associated with gene amplification in HPV-negative HNSCC cell lines and clinical tumors. In two independent cohorts of patients with locally advanced HPV-negative HNSCC, PTK2/FAK amplification was highly associated with poorer disease-free survival (DFS) (P=0.012 and P=0.034). PTK2/FAK mRNA expression was also associated with worse DFS (P=0.03). Moreover, both PTK2/FAK mRNA (P=0.021) and copy number (P=0.063) were associated with DFS in the Head and Neck Cancer subgroup of The Cancer Genome Atlas. Conclusion Proteomic analysis identified PTK2/FAK overexpression is a biomarker of radioresistance in locally advanced HNSCC, and PTK2/FAK inhibition radiosensitized HNSCC cells. Combinations of PTK2/FAK inhibition with radiotherapy merit further evaluation as a therapeutic strategy for improving local control in HPV-negative HNSCC. PMID:27036135

  11. CD133+ cells contribute to radioresistance via altered regulation of DNA repair genes in human lung cancer cells

    International Nuclear Information System (INIS)

    Desai, Amar; Webb, Bryan; Gerson, Stanton L.

    2014-01-01

    Background: Radioresistance in human tumors has been linked in part to a subset of cells termed cancer stem cells (CSCs). The prominin 1 (CD133) cell surface protein is proposed to be a marker enriching for CSCs. We explore the importance of DNA repair in contributing to radioresistance in CD133+ lung cancer cells. Materials and methods: A549 and H1299 lung cancer cell lines were used. Sorted CD133+ cells were exposed to either single 4 Gy or 8 Gy doses and clonogenic survival measured. ϒ-H2AX immunofluorescence and quantitative real time PCR was performed on sorted CD133+ cells both in the absence of IR and after two single 4 Gy doses. Lentiviral shRNA was used to silence repair genes. Results: A549 but not H1299 cells expand their CD133+ population after single 4 Gy exposure, and isolated A549 CD133+ cells demonstrate IR resistance. This resistance corresponded with enhanced repair of DNA double strand breaks (DSBs) and upregulated expression of DSB repair genes in A549 cells. Prior IR exposure of two single 4 Gy doses resulted in acquired DNA repair upregulation and improved repair proficiency in both A549 and H1299. Finally Exo1 and Rad51 silencing in A549 cells abrogated the CD133+ IR expansion phenotype and induced IR sensitivity in sorted CD133+ cells. Conclusions: CD133 identifies a population of cells within specific tumor types containing altered expression of DNA repair genes that are inducible upon exposure to chemotherapy. This altered gene expression contributes to enhanced DSB resolution and the radioresistance phenotype of these cells. We also identify DNA repair genes which may serve as promising therapeutic targets to confer radiosensitivity to CSCs

  12. Genomic amplification of Fanconi anemia complementation group A (FancA) in head and neck squamous cell carcinoma (HNSCC): Cellular mechanisms of radioresistance and clinical relevance.

    Science.gov (United States)

    Hess, Julia; Unger, Kristian; Orth, Michael; Schötz, Ulrike; Schüttrumpf, Lars; Zangen, Verena; Gimenez-Aznar, Igor; Michna, Agata; Schneider, Ludmila; Stamp, Ramona; Selmansberger, Martin; Braselmann, Herbert; Hieber, Ludwig; Drexler, Guido A; Kuger, Sebastian; Klein, Diana; Jendrossek, Verena; Friedl, Anna A; Belka, Claus; Zitzelsberger, Horst; Lauber, Kirsten

    2017-02-01

    Radio (chemo) therapy is a crucial treatment modality for head and neck squamous cell carcinoma (HNSCC), but relapse is frequent, and the underlying mechanisms remain largely elusive. Therefore, novel biomarkers are urgently needed. Previously, we identified gains on 16q23-24 to be associated with amplification of the Fanconi anemia A (FancA) gene and to correlate with reduced progression-free survival after radiotherapy. Here, we analyzed the effects of FancA on radiation sensitivity in vitro, characterized the underlying mechanisms, and evaluated their clinical relevance. Silencing of FancA expression in HNSCC cell lines with genomic gains on 16q23-24 resulted in significantly impaired clonogenic survival upon irradiation. Conversely, overexpression of FancA in immortalized keratinocytes conferred increased survival accompanied by improved DNA repair, reduced accumulation of chromosomal translocations, but no hyperactivation of the FA/BRCA-pathway. Downregulation of interferon signaling as identified by microarray analyses, enforced irradiation-induced senescence, and elevated production of the senescence-associated secretory phenotype (SASP) appeared to be candidate mechanisms contributing to FancA-mediated radioresistance. Data of the TCGA HNSCC cohort confirmed the association of gains on 16q24.3 with FancA overexpression and impaired overall survival. Importantly, transcriptomic alterations similar to those observed upon FancA overexpression in vitro strengthened the clinical relevance. Overall, FancA amplification and overexpression appear to be crucial for radiotherapeutic failure in HNSCC. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  13. Identification of CD133-positive radioresistant cells in atypical teratoid/rhabdoid tumor.

    Directory of Open Access Journals (Sweden)

    Shih-Hwa Chiou

    2008-05-01

    Full Text Available Atypical teratoid/rhabdoid tumor (AT/RT is an extremely malignant neoplasm in the central nervous system (CNS which occurs in infancy and childhood. Recent studies suggested that CD133 could be considered a marker for brain cancer stem-like cells (CSCs. However, the role of CD133 in AT/RT has never been investigated. Herein we report the isolation of CD133-positive cells (CD133(+, found to have the potential to differentiate into three germ layer tissues, from tissues of nine AT/RT patients. The migration/invasion/malignancy and radioresistant capabilities of CD133(+ were significantly augmented when compared to CD133(-. The clinical data showed that the amount of CD133(+ in AT/RTs correlated positively with the degree of resistance to radiation therapy. Using cDNA microarray analysis, the genotoxic-response profiles of CD133(+ and CD133(- irradiated with 10 Gy ionizing radiation (IR were analyzed 0.5, 2, 6, 12 and 24 h post-IR. We then validated these microarray data and showed increased phosphorylation after IR of p-ATM, p-RAD17, and p-CHX2 as well as increased expression of BCL-2 protein in CD133(+ compared to CD133(-. Furthermore, we found that CD133(+ can effectively resist IR with cisplatin- and/or TRAIL-induced apoptosis. Immunohistochemical analysis confirmed the up-regulated expression of p-ATM and BCL-2 proteins in IR-treated CD133(+ xenotransgrafts in SCID mice but not in IR-treated CD133(-. Importantly, the effect of IR in CD133(+ transplanted mice can be significantly improved by a combination of BCL-2 siRNA with debromohymenialdisine, an inhibitor of checkpoint kinases. In sum, this is the first report indicating that CD133(+ AT/RT cells demonstrate the characteristics of CSCs. The IR-resistant and anti-apoptotic properties in CD133(+ may reflect the clinical refractory malignancy of AT/RTs and thus the activated p-ATM pathway and BCL-2 expression in CD133(+ could be possible targets to improve future treatment of deadly diseases

  14. Melatonin suppresses thyroid cancer growth and overcomes radioresistance via inhibition of p65 phosphorylation and induction of ROS

    Directory of Open Access Journals (Sweden)

    Zhen-Wei Zou

    2018-06-01

    Full Text Available Thyroid cancer is the most common endocrine carcinoma with increasing incidence worldwide and anaplastic subtypes are frequently associated with cancer related death. Radioresistance of thyroid cancer often leads to therapy failure and cancer-related death. In this study, we found that melatonin showed potent suppressive roles on NF-κB signaling via inhibition of p65 phosphorylation and generated redox stress in thyroid cancer including the anaplastic subtypes. Our data showed that melatonin significantly decreased cell viability, suppressed cell migration and induced apoptosis in thyroid cancer cell lines in vitro and impaired tumor growth in the subcutaneous mouse model in vivo. By contrast, irradiation of thyroid cancer cells resulted in elevated level of phosphorylated p65, which could be reversed by cotreatment with melatonin. Consequently, melatonin synergized with irradiation to induce cytotoxicity to thyroid cancer, especially in the undifferentiated subgroups. Taken together, our results suggest that melatonin may exert anti-tumor activities against thyroid carcinoma by inhibition of p65 phosphorylation and induction of reactive oxygen species. Radio-sensitization by melatonin may have clinical benefits in thyroid cancer. Keywords: Melatonin, Thyroid cancer, Radioresistance, p65, Reactive oxygen species

  15. Cytogenetic Effects of Low Dose Radiation in Mammalian Cells Analysis of the Phenomenon Hypersensitivity and Induced Radioresistence

    CERN Document Server

    Shmakova, N L; Nasonova, E A; Krasavin, E A; Rsjanina, A V

    2001-01-01

    The induction of cytogenetic damage after irradiation of chinese hamster cells and human melanoma cells within dose range 1-200 cGy was studied. The anaphase and metaphase analysis of chromosome damage and micronuclei test were applied. The hypersensitivity (HRS) at doses below 20 cGy and the increased radioresistence at higher doses (IR) were shown with all cytogenetic criteria for both cell lines. The phenomenon of HRS/IR was reproduced in synchronic as well as in asynchronic population of chinese hamster cells. This fact shows that HRS was caused by high radiosensitivity of all cells and can not be explained by any differential sensitivity of cells in different phases of the cell cycle. So it was supposed that the increasing radioresistence is determined by the inclusion of the inducible repair processes in all cells. This conclusion agress with the fact that there was no evidence of HRS on dose-effect curves and that some part of pre-existent damage was repaired after preliminary irradiation with low dose...

  16. Intrathymic radioresistant stem cells follow an IL-2/IL-2R pathway during thymic regeneration after sublethal irradiation

    International Nuclear Information System (INIS)

    Zuniga-Pfluecker, J.C.K.; Kruisbeek, A.M.

    1990-01-01

    Sublethally irradiated mice undergo thymic regeneration which follows a phenotypic pattern of events similar to that observed during normal fetal development. Thymic regeneration after irradiation is the product of a limited pool of intrathymic radioresistant stem cells undergoing simultaneous differentiation. We show that in this model of T cell development, thymic regeneration follows a pathway in which the IL-2R is transiently expressed on CD4-/CD8- cells. IL-2R expression occurred during the exponential growth period of thymic regeneration, and IL-2R blocking prevented this explosive growth. Flow cytometry analysis revealed that the IL-2R blockade affected primarily the development of the immature CD3-/CD4-/CD8- (triple negative) cells and their ability to generate CD3+/CD4+/CD8+ or CD3+/CD4+/CD8- and CD3+/CD4-/CD8+ thymocytes. Thus, our findings demonstrate that blocking of the IL-2R resulted in an arrest in proliferation and differentiation by intrathymic radioresistant stem cells, indicating that the IL-2/IL-2R pathway is necessary for the expansion of immature triple negative T cells

  17. A preliminary investigation into the extent of increased radioresistance or hyper-radiosensitivity in cells of hamster cell lines known to be deficient in DNA repair

    International Nuclear Information System (INIS)

    Skov, K.; Marples, B.; Matthews, J.B.; Zhou, H.; Joiner, M.C.

    1994-01-01

    The response to low doses of X rays was assessed in cells of three hamster cell lines which are defective in DNA repair and was compared with their parental lines. Cells of the V79-derived double-strand break repair-deficient line XR-V15B showed no radioresistance in the 0.5-Gy range compared with the V79B wild type, but instead showed an exponential response. Cells of the single-strand break repair-deficient line EM9 showed hyper-radiosensitivity and exhibited increased radioresistance. Most interestingly, cells of the UV-20 cell line appeared to respond exponentially, as a continuation of the hyper-radiosensitive portion of the curve, with no evidence of increased radioresistance. This line is defective in an incision step of excision repair and is sensitive to crosslinking agents. Further studies are warranted to address the possible role of single- and double-strand break repair and excision repair in hyper-radiosensitivity and increased radioresistance. 24 refs., 4 figs

  18. Lambda bacteriophage gene products and x-ray sensitivity of Escherichia coli: comparison of red-dependent and gam-dependent radioresistance

    International Nuclear Information System (INIS)

    Trgovcevic, Z.; Rupp, W.D.

    1975-01-01

    When gene products of lambda bacteriophage are introduced into a cell by transient induction of a lysogen, increased resistance of the cells to x rays results. This phenomenon has been called phage-induced radioresistance. Genetic studies show at least two classes of induced radioresistance. The first type depends on the products of the lambda red genes and is observed in bacteria that are mutated in the recB gene. It is thought that the lambda red products compensate for the missing RecBC nuclease in the repair of x-ray damage. An optimal effect is obtained even when the lambda red products are supplied 1 h after irradiation. The lesions that are affected by the red-dependent process are probably not deoxyribonucleic acid strand breaks because the extent of deoxyribonucleic acid strand rejoining is not altered by the red products. The second type of phage-induced radioresistance requires the gam product of lambda and is observed in wild-type and polA strains. The lambda gam + gene product must be present immediately after irradiation to exert its full effect. In its presence, DNA breakdown is decreased, and a greater fraction of DNA is converted back to high molecular weight. Strains carrying lex, recA, or certain other combinations of mutations do not show any detectable phage-induced radioresistance. (U.S.)

  19. The influence of nalidixic acid and nicotinamide of the radiation-induced cytogenetic injury to hexaploid wheat varities contrast by radioresistance

    International Nuclear Information System (INIS)

    Selezneva, E.M.; Sarapul'tsev, B.I.

    1990-01-01

    Nalidixic acid modifies the cytogenetic injury when only applied to seeds of a radiosensitive variety, Moskovskaya 35. The radioprotective effect of nicotinamide on both radiosensitive and radioresistant hexaploid wheat varities is observed being dependent on the extent which the genetic apparatus is impaired

  20. Role of insulin-like growth factor-I receptor (IGF-IR) in survival kinetics and radioresistance of mouse embryo fibroblasts in a hypoxic environment

    International Nuclear Information System (INIS)

    Okochi, Kiyoshi

    2002-01-01

    The role of insulin-like growth factor-I receptor (IGF-IR) in survival kinetics and radioresistance of fibroblasts in a severely hypoxic environment (partial oxygen pressure of less than 3 mmHg) was analyzed, in both low and high cell-density conditions. Mouse embryonic fibroblasts R(-), with a targeted disruption of the IGF-IR gene, and R(+) cells, derived from R(-) cells stably transfected with a plasmid containing a human IGF-IR cDNA, were used for this purpose. Survival time in hypoxia was longer in R(+) cells than R(-) cells, which correlated with highly elevated expression of caspase 3-like activity in R(-) cells, but not with HIF-Iα expression. Under euoxia, R(+) cells were more radioresistant, by a factor of 1.9, than R(-) cells. Under hypoxia, R(+) cells became more radioresistant, with an oxygen-enhancement ratio (OER) of 2.7, than R(-) cells, with an OER of 1.5, in a low cell density. However, unexpected hyper-radiosensitivity in hypoxia was observed for both R(+) and R(-) cells in a high cell density, which further increased with incubation time in hypoxia following X-irradiation. The hyper-radiosensitivity was more pronounced for R(-) cells. The result thus implies that IGF-IR may be an important target molecule for radioresistant tumors in radiotherapy. (author)

  1. The role of natural radioresistance and ecological specialization of a specie in radio adaptation (as exemplified by natural rodent populations)

    Energy Technology Data Exchange (ETDEWEB)

    Grigorkina, E.; Olenev, G. [Institute of Plant and Animal Ecology, Ural Branch RAS, Ekaterinburg, (Russian Federation)

    2004-07-01

    The problem of mammal radio-adaptation is closely connected with problems of micro-evolution and prediction of the fate of irradiated populations. This report gives new materials on radio-adaptation of small mammals inhabiting the East Ural Radioactive Trace (EURT) which has been formed after the Kyshtym accident in 1957 year. The EURT zone is a unique area for studying long-term consequences of chronic low-dose irradiation of small mammal populations many generations being born after the accident. The role of natural radioresistance, ecological specialization and biological characteristics of a specie in the development of radio-adaptation are discussed. The objects of investigation were rodents: 1) Ellobius talpinus is a peculiar specialized specie with low ability to migrate, burrowing underground way of life and lifespan up to 6 years; 2) Sylvaemus uralensis, Apodemus agrarius, Clethrionomys rutilus widespread aboveground species, very active migrators with a 1.5 year lifespan. Significant differences were found among species in natural radioresistance to acute gamma-irradiation. LD{sub 50/30} is 5.0{+-}0.7 Gy for the Ellobius talpinus, 7.0{+-}0.4 Gy for the Sylvaemus uralensis, 10.0{+-}0.2 Gy for the Apodemus agrarius, 12.8{+-}0.2 Gy for the Clethrionomys rutilus. Despite the high radiosensitivity the Ellobius talpinus was more tolerant to chronic irradiation (over 45 years inhabiting the EURT, soil pollution by {sup 90}Sr was 950-1050 Ci/km{sup 2} - 35-39 MBq/m{sup 2}) in a complex of morpho-physiological, haematological and immunological parameters, than other species with active migration activity (the initial pollution of soil by {sup 90}Sr was 400-540 Ci/km{sup 2} - 15-20 MBq/m{sup 2}). This phenomenon is explained by radio-adaptation which developed in the Ellobius talpinus due to isolation of their settlement in the periphery of the area in conditions of radio-contamination. Various radioresistance to acute and chronic irradiation, disproportion of

  2. Cancer-initiating cells derived from established cervical cell lines exhibit stem-cell markers and increased radioresistance

    International Nuclear Information System (INIS)

    López, Jacqueline; Poitevin, Adela; Mendoza-Martínez, Veverly; Pérez-Plasencia, Carlos; García-Carrancá, Alejandro

    2012-01-01

    Cancer-initiating cells (CICs) are proposed to be responsible for the generation of metastasis and resistance to therapy. Accumulating evidences indicates CICs are found among different human cancers and cell lines derived from them. Few studies address the characteristics of CICs in cervical cancer. We identify biological features of CICs from four of the best-know human cell lines from uterine cervix tumors. (HeLa, SiHa, Ca Ski, C-4 I). Cells were cultured as spheres under stem-cell conditions. Flow cytometry was used to detect expression of CD34, CD49f and CD133 antigens and Hoechst 33342 staining to identify side population (SP). Magnetic and fluorescence-activated cell sorting was applied to enrich and purify populations used to evaluate tumorigenicity in nude mice. cDNA microarray analysis and in vitro radioresistance assay were carried out under standard conditions. CICs, enriched as spheroids, were capable to generate reproducible tumor phenotypes in nu-nu mice and serial propagation. Injection of 1 × 10 3 dissociated spheroid cells induced tumors in the majority of animals, whereas injection of 1 × 10 5 monolayer cells remained nontumorigenic. Sphere-derived CICs expressed CD49f surface marker. Gene profiling analysis of HeLa and SiHa spheroid cells showed up-regulation of CICs markers characteristic of the female reproductive system. Importantly, epithelial to mesenchymal (EMT) transition-associated markers were found highly expressed in spheroid cells. More importantly, gene expression analysis indicated that genes required for radioresistance were also up-regulated, including components of the double-strand break (DSB) DNA repair machinery and the metabolism of reactive oxygen species (ROS). Dose-dependent radiation assay indicated indeed that CICs-enriched populations exhibit an increased resistance to ionizing radiation (IR). We characterized a self-renewing subpopulation of CICs found among four well known human cancer-derived cell lines (HeLa, Si

  3. MiR-20a Induces Cell Radioresistance by Activating the PTEN/PI3K/Akt Signaling Pathway in Hepatocellular Carcinoma

    International Nuclear Information System (INIS)

    Zhang, Yuqin; Zheng, Lin; Ding, Yi; Li, Qi; Wang, Rong; Liu, Tongxin; Sun, Quanquan; Yang, Hua; Peng, Shunli; Wang, Wei; Chen, Longhua

    2015-01-01

    Purpose: To investigate the role of miR-20a in hepatocellular carcinoma (HCC) cell radioresistance, which may reveal potential strategies to improve treatment. Methods and Materials: The expression of miR-20a and PTEN were detected in HCC cell lines and paired primary tissues by quantitative real-time polymerase chain reaction. Cell radiation combined with colony formation assays was administrated to discover the effect of miR-20a on radiosensitivity. Bioinformatics prediction and luciferase assay were used to identify the target of miR-20a. The phosphatidylinositol 3-kinase inhibitor LY294002 was used to inhibit phosphorylation of Akt, to verify whether miR-20a affects HCC cell radioresistance through activating the PTEN/PI3K/Akt pathway. Results: MiR-20a levels were increased in HCC cell lines and tissues, whereas PTEN was inversely correlated with it. Overexpression of miR-20a in Bel-7402 and SMMC-7721 cells enhances their resistance to the effect of ionizing radiation, and the inhibition of miR-20a in HCCLM3 and QGY-7701 cells sensitizes them to it. PTEN was identified as a direct functional target of miR-20a for the induction of radioresistance. Overexpression of miR-20a activated the PTEN/PI3K/Akt signaling pathway. Additionally, the kinase inhibitor LY294002 could reverse the effect of miR-20a–induced radioresistance. Conclusion: MiR-20a induces HCC cell radioresistance by activating the PTEN/PI3K/Akt pathway, which suggests that miR-20a/PTEN/PI3K/Akt might represent a target of investigation for developing effective therapeutic strategies against HCC

  4. Searching for a strategy to gamma-sterilize Portuguese cork stoppers - preliminary studies on bioburden, radioresistance and sterility assurance level

    International Nuclear Information System (INIS)

    Botelho, M.L.; Almeida-Vara, E.; Andrade, M.E.; Tenreiro, R.

    1988-01-01

    A gamma radiation plant will start running next year in Portugal, to sterilize medical devices and wine cork stoppers. As Portugal is the first world producer, manufacturer and exporter of wine cork stoppers, an efficient sterilizing procedure is required to overcome moulding from long term shipping. Preliminary research on cork stoppers bioburden and microflora radioresistance allowed to establish reliable D 10 and Sterility Assurance Level (SAL) values. Studied samples showed an initial average contamination of about 10 4 c.f.u. per cork stopper. The determined D 10 values for fungi were not higher than 2 kGy. In these conditions, a SAL of 10 -4 can be expected when the product is treated at a minimum absorbed dose of 15 kGy. (author)

  5. Upregulation of Long Noncoding RNA Small Nucleolar RNA Host Gene 18 Promotes Radioresistance of Glioma by Repressing Semaphorin 5A

    Energy Technology Data Exchange (ETDEWEB)

    Zheng, Rong [Department of Radiation Oncology, Nanfang Hospital, Southern Medical University, Guangzhou, Guangdong (China); Department of Radiation Oncology, Fujian Medical University Union Hospital, Fuzhou, Fujian (China); Yao, Qiwei [Department of Radiation Oncology, Nanfang Hospital, Southern Medical University, Guangzhou, Guangdong (China); Department of Radiation Oncology, Teaching Hospital of Fujian Medical University, Fujian Provincial Cancer Hospital, Fuzhou, Fujian (China); Ren, Chen; Liu, Ying; Yang, Hongli; Xie, Guozhu; Du, Shasha [Department of Radiation Oncology, Nanfang Hospital, Southern Medical University, Guangzhou, Guangdong (China); Yang, Kaijun [Department of Neurosurgery, Nanfang Hospital, Southern Medical University, Guangzhou, Guangdong (China); Yuan, Yawei, E-mail: yuanyawei2015@outlook.com [Department of Radiation Oncology, Nanfang Hospital, Southern Medical University, Guangzhou, Guangdong (China); Department of Radiation Oncology, Cancer Hospital Center of Guangzhou Medical University, Guangzhou, Guangdong (China)

    2016-11-15

    Purpose: Although increasing evidence has shown that long noncoding RNAs play an important regulatory role in carcinogenesis and tumor progression, little is known about the role of small nucleolar RNA host gene 18 (SNHG18) in cancer. The goal of this study was to investigate the expression of SNHG18 and its clinical significance in glioma. Methods and Materials: Differences in the lncRNA expression profile between M059K and M059J cells were assessed by lncRNA expression microarray analysis. The expression and localization of SNHG18 in glioma cells or tissues was evaluated by quantitative reverse transcription-polymerase chain reaction (qRT-PCR) and in situ hybridization (ISH), respectively. the clinical associations of SNHG18 in glioma was evaluated by qRT-PCR, ISH and immunohistochemistry. The role of SNHG18 in glioma radiosensitivity was evaluated by colony formation assays, immunofluorescence, Western blot and tumor growth inhibition study. Results: The present study investigated the clinical associations of SNHG18 and its role in glioma. Our results showed that the expression of SNHG18 was remarkably upregulated in clinical glioma tissues compared with normal brain tissues. SNHG18 expression was associated with the clinical tumor grade and correlated negatively with isocitrate dehydrogenase 1 mutation. In addition, knockdown of SNHG18 with short hairpin RNA suppressed the radioresistance of glioma cells, and transgenic expression of SNHG18 had the opposite effect. Furthermore, xenograft tumors grown from cells with SNHG18 deletion were more radiosensitive than tumors grown from control cells. Further studies revealed that SNHG18 promotes radioresistance by inhibiting semaphorin 5A and that inhibition of semaphorin 5A expression abrogated the radiosensitizing effect caused by SNHG18 deletion. Conclusions: Our findings provide new insights into the role of SNHG18 in glioma and suggest its potential as a target for glioma therapy.

  6. Pim-3 contributes to radioresistance through regulation of the cell cycle and DNA damage repair in pancreatic cancer cells

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Xiang-Yuan; Wang, Zhen [Cancer Research Institute, Fudan University Shanghai Cancer Center, Department of Oncology, Shanghai Medical College, Fudan University, Shanghai (China); Li, Bei [Department of Nuclear Medicine, Fudan University Shanghai Cancer Center, Department of Oncology, Shanghai Medical College, Fudan University, Shanghai (China); Zhang, Ying-Jian, E-mail: yjzhang111@aliyun.com [Department of Nuclear Medicine, Fudan University Shanghai Cancer Center, Department of Oncology, Shanghai Medical College, Fudan University, Shanghai (China); Li, Ying-Yi, E-mail: liyingyi@fudan.edu.cn [Cancer Research Institute, Fudan University Shanghai Cancer Center, Department of Oncology, Shanghai Medical College, Fudan University, Shanghai (China)

    2016-04-22

    Resistance of cancer cells to chemoradiotherapy is a major clinical problem in pancreatic cancer treatment. Therefore, understanding the molecular basis of cellular resistance and identifying novel targets are essential for improving treatment efficacy for pancreatic cancer patients. Previous studies have demonstrated a significant role for Pim-3 in pancreatic cancer survival against gemcitabine-induced genotoxic stress. Here, we observed that radiation treatment enhanced Pim-3 expression in human pancreatic cancer cells in vitro. Stable overexpression of Pim-3 in pancreatic cancer cells significantly protected cells against radiation treatment by attenuating G2/M phase cell cycle arrest and DNA damage response. Silencing of Pim-3 expression significantly elevated the phosphorylation of histone variant H2AX, a marker of DNA double strand breaks, and decreased the activation of ataxia-telangiectasia-mutated (ATM) kinase, along with its downstream targets, eventually enhancing the radiosensitivity of human pancreatic cancer cells in vitro and in vivo. Hence, we demonstrated a novel function for Pim-3 in human pancreatic cancer cell survival against radiation. Targeting Pim-3 may be a promising way to improve treatment efficacy in combination with radiotherapy in human pancreatic cancer. - Highlights: • This is first study to demonstrate that Pim-3 is endogenously induced by ionizing radiation in pancreatic cancer cells, and Pim-3 overexpression enhanced radioresistance of pancreatic cancer cells both in vitro and in vivo. • This is first study to provide evidence that radioresistance induced by Pim-3 is mainly attributed to Pim-3 induces activation of ATM, which subsequently activates checkpoint 1, leading to amplification of DNA repair through cell cycle arrest and DNA repair pathways. • This is first study to indicate that targeting Pim-3 may be a promising strategy to provide better treatment efficacy in combination with radiotherapy in human pancreatic

  7. KNK437, abrogates hypoxia-induced radioresistance by dual targeting of the AKT and HIF-1α survival pathways

    International Nuclear Information System (INIS)

    Oommen, Deepu; Prise, Kevin M.

    2012-01-01

    Highlights: ► KNK437, a benzylidene lactam compound, is a novel radiosensitizer. ► KNK437 inhibits AKT signaling and abrogates the accumulation of HIF-1α under hypoxia. ► KNK437 abrogates hypoxia induced resistance to radiation. -- Abstract: KNK437 is a benzylidene lactam compound known to inhibit stress-induced synthesis of heat shock proteins (HSPs). HSPs promote radioresistance and play a major role in stabilizing hypoxia inducible factor-1α (HIF-1α). HIF-1α is widely responsible for tumor resistance to radiation under hypoxic conditions. We hypothesized that KNK437 sensitizes cancer cells to radiation and overrides hypoxia-induced radioresistance via destabilizing HIF-1α. Treatment of human cancer cells MDA-MB-231 and T98G with KNK437 sensitized them to ionizing radiation (IR). Surprisingly, IR did not induce HSPs in these cell lines. As hypothesized, KNK437 abrogated the accumulation of HIF-1α in hypoxic cells. However, there was no induction of HSPs under hypoxic conditions. Moreover, the proteosome inhibitor MG132 did not restore HIF-1α levels in KNK437-treated cells. This suggested that the absence of HIF-1α in hypoxic cells was not due to the enhanced protein degradation. HIF-1α is mainly regulated at the level of post-transcription and AKT is known to modulate the translation of HIF-1α mRNA. Interestingly, pre-treatment of cells with KNK437 inhibited AKT signaling. Furthermore, down regulation of AKT by siRNA abrogated HIF-1α levels under hypoxia. Interestingly, KNK437 reduced cell survival in hypoxic conditions and inhibited hypoxia-induced resistance to radiation. Taken together, these data suggest that KNK437 is an effective radiosensitizer that targets multiple pro-survival stress response pathways.

  8. Radioresistant head and neck squamous cell carcinoma cells: Intracellular signaling, putative biomarkers for tumor recurrences and possible therapeutic targets

    International Nuclear Information System (INIS)

    Skvortsov, Sergej; Jimenez, Connie R.; Knol, Jaco C.; Eichberger, Paul; Schiestl, Bernhard; Debbage, Paul; Skvortsova, Ira; Lukas, Peter

    2011-01-01

    Purpose: Treatment of local and distant head and neck cancer recurrences after radiotherapy remains an unsolved problem. In order to identify potential targets for use in effective therapy of recurrent tumors, we have investigated protein patterns in radioresistant (FaDu-IRR and SCC25-IRR, “IRR cells”) as compared to parental (FaDu and SCC25) head and neck carcinoma cells. Methods and materials: Radiation resistant IRR cells were derived from parental cells after repeated exposure to ionizing radiation 10 times every two weeks at a single dose of 10 Gy, resulting in a total dose of 100 Gy. Protein profiling in parental and IRR cells was carried out using two-dimensional differential gel electrophoresis (2D-DIGE) followed by MALDI-TOF/TOF mass spectrometry. Cell viability, cell migration assays and Western blot analysis were used to confirm results obtained using the proteome approach. Results: Forty-five proteins that were similarly modulated in FaDu-IRR and SCC25-IRR cells compared to parental cells were selected to analyze their common targets. It was found that these either up- or down-regulated proteins are closely related to the enhancement of cell migration which is regulated by Rac1 protein. Further investigations confirmed that Rac1 is up-regulated in IRR cells, and inhibiting its action reduces the migratory abilities of these cells. Additionally, the Rac1 inhibitor exerts cytostatic effects in HNSCC cells, mostly in migratory cells. Conclusions: Based on these results, we conclude that radioresistant HNSCC cells possess enhanced metastatic abilities that are regulated by a network of migration-related proteins. Rac1 protein may be considered as a putative biomarker of HNSCC radiation resistance, and as a potential therapeutic target for treating local and distant HNSCC recurrences.

  9. Pim-3 contributes to radioresistance through regulation of the cell cycle and DNA damage repair in pancreatic cancer cells

    International Nuclear Information System (INIS)

    Chen, Xiang-Yuan; Wang, Zhen; Li, Bei; Zhang, Ying-Jian; Li, Ying-Yi

    2016-01-01

    Resistance of cancer cells to chemoradiotherapy is a major clinical problem in pancreatic cancer treatment. Therefore, understanding the molecular basis of cellular resistance and identifying novel targets are essential for improving treatment efficacy for pancreatic cancer patients. Previous studies have demonstrated a significant role for Pim-3 in pancreatic cancer survival against gemcitabine-induced genotoxic stress. Here, we observed that radiation treatment enhanced Pim-3 expression in human pancreatic cancer cells in vitro. Stable overexpression of Pim-3 in pancreatic cancer cells significantly protected cells against radiation treatment by attenuating G2/M phase cell cycle arrest and DNA damage response. Silencing of Pim-3 expression significantly elevated the phosphorylation of histone variant H2AX, a marker of DNA double strand breaks, and decreased the activation of ataxia-telangiectasia-mutated (ATM) kinase, along with its downstream targets, eventually enhancing the radiosensitivity of human pancreatic cancer cells in vitro and in vivo. Hence, we demonstrated a novel function for Pim-3 in human pancreatic cancer cell survival against radiation. Targeting Pim-3 may be a promising way to improve treatment efficacy in combination with radiotherapy in human pancreatic cancer. - Highlights: • This is first study to demonstrate that Pim-3 is endogenously induced by ionizing radiation in pancreatic cancer cells, and Pim-3 overexpression enhanced radioresistance of pancreatic cancer cells both in vitro and in vivo. • This is first study to provide evidence that radioresistance induced by Pim-3 is mainly attributed to Pim-3 induces activation of ATM, which subsequently activates checkpoint 1, leading to amplification of DNA repair through cell cycle arrest and DNA repair pathways. • This is first study to indicate that targeting Pim-3 may be a promising strategy to provide better treatment efficacy in combination with radiotherapy in human pancreatic

  10. Upregulation of Long Noncoding RNA Small Nucleolar RNA Host Gene 18 Promotes Radioresistance of Glioma by Repressing Semaphorin 5A

    International Nuclear Information System (INIS)

    Zheng, Rong; Yao, Qiwei; Ren, Chen; Liu, Ying; Yang, Hongli; Xie, Guozhu; Du, Shasha; Yang, Kaijun; Yuan, Yawei

    2016-01-01

    Purpose: Although increasing evidence has shown that long noncoding RNAs play an important regulatory role in carcinogenesis and tumor progression, little is known about the role of small nucleolar RNA host gene 18 (SNHG18) in cancer. The goal of this study was to investigate the expression of SNHG18 and its clinical significance in glioma. Methods and Materials: Differences in the lncRNA expression profile between M059K and M059J cells were assessed by lncRNA expression microarray analysis. The expression and localization of SNHG18 in glioma cells or tissues was evaluated by quantitative reverse transcription-polymerase chain reaction (qRT-PCR) and in situ hybridization (ISH), respectively. the clinical associations of SNHG18 in glioma was evaluated by qRT-PCR, ISH and immunohistochemistry. The role of SNHG18 in glioma radiosensitivity was evaluated by colony formation assays, immunofluorescence, Western blot and tumor growth inhibition study. Results: The present study investigated the clinical associations of SNHG18 and its role in glioma. Our results showed that the expression of SNHG18 was remarkably upregulated in clinical glioma tissues compared with normal brain tissues. SNHG18 expression was associated with the clinical tumor grade and correlated negatively with isocitrate dehydrogenase 1 mutation. In addition, knockdown of SNHG18 with short hairpin RNA suppressed the radioresistance of glioma cells, and transgenic expression of SNHG18 had the opposite effect. Furthermore, xenograft tumors grown from cells with SNHG18 deletion were more radiosensitive than tumors grown from control cells. Further studies revealed that SNHG18 promotes radioresistance by inhibiting semaphorin 5A and that inhibition of semaphorin 5A expression abrogated the radiosensitizing effect caused by SNHG18 deletion. Conclusions: Our findings provide new insights into the role of SNHG18 in glioma and suggest its potential as a target for glioma therapy.

  11. Does the cell radioresistance acquired by low dose-rate gamma irradiation depend on genetic factors or physiological changes. Study carried out on inactive cells of the unicellular green alga Chlorella pyrenoidosa CHICK

    International Nuclear Information System (INIS)

    Dettwiller, Pascale.

    1982-09-01

    Inactive cells of the unicellular green alga Chlorella pyrenoidosa CHICK were used to test the following hypothesis: the radioresistance acquired by these cells after irradiation at low dose rate (0.06 Gy/mn) is due to the selection or induction of radioresistant clones. Clone cultures were grown mainly from colonies exhibiting defects (high cell loss, slowed growth, pigment deficiency). Of thirty clones studied, three only of second and third separations possessed the radioresistance of their original population. On the basis of these results, backed up by a first experiment which shows the loss of cell radioresistance when continuous irradiation is stopped, the initial hypothesis may be dismissed and research directed towards changes relative to cell restoration processes by irradiation at low dose rates [fr

  12. DNA and protein co-administration induces tolerogenic dendritic cells through DC-SIGN mediated negative signals.

    Science.gov (United States)

    Li, Jinyao; Geng, Shuang; Liu, Xiuping; Liu, Hu; Jin, Huali; Liu, Chang-Gong; Wang, Bin

    2013-10-01

    We previously demonstrated that DNA and protein co-administration induced differentiation of immature dendritic cells (iDCs) into CD11c(+)CD40(low)IL-10(+) regulatory DCs (DCregs) via the caveolin-1 (Cav-1) -mediated signal pathway. Here, we demonstrate that production of IL-10 and the low expression of CD40 play a critical role in the subsequent induction of regulatory T cells (Tregs) by the DCregs. We observed that DNA and protein were co-localized with DC-SIGN in caveolae and early lysosomes in the treated DCs, as indicated by co-localization with Cav-1 and EEA-1 compartment markers. DNA and protein also co-localized with LAMP-2. Gene-array analysis of gene expression showed that more than a thousand genes were significantly changed by the DC co-treatment with DNA + protein compared with controls. Notably, the level of DC-SIGN expression was dramatically upregulated in pOVA + OVA co-treated DCs. The expression levels of Rho and Rho GNEF, the down-stream molecules of DC-SIGN mediated signal pathway, were also greatly upregulated. Further, the level of TLR9, the traditional DNA receptor, was significantly downregulated. These results suggest that DC-SIGN as the potential receptor for DNA and protein might trigger the negative pathway to contribute the induction of DCreg combining with Cav-1 mediated negative signal pathway.

  13. Molecular and functional analysis of DIR1; a novel gene with a potential role in induced radioresistance

    International Nuclear Information System (INIS)

    Young, S.M.; McKeen, H.; Valentine, A.; Burke, G.; Hirst, D.; Robson, T.

    2003-01-01

    Full text: There is now little doubt about the existence of radioprotective mechanisms that are upregulated following exposure to small doses of ionizing radiation and other DNA-damaging agents. The identification of genes whose expression is altered following exposure to a low dose of ionizing radiation will be an important step in understanding these phenomena. We have identified a novel gene, DIR1, that is transiently repressed by low radiation doses (Robson et al.,1997 and 1999) and is otherwise expressed in a wide range of cell lines and tissues. The repression of this gene is in the dose range where induced radioresistance is observed in a number of cell survival studies (Joiner et al., 2001) implicating this gene in induced radioresistance. Using antisense strategies, we have demonstrated that the DIR1 gene product appears to be involved in cell survival and DNA repair in a range of cell lines following exposure to X-rays (Robson et al., 1999 and 2000). Using microchip array analysis we have been able to identify a number of genes activated as a consequence of DIR1 repression. Preliminary data implicate genes involved in repair, cell cycle and stress response and include ATM and BRCA2. We are now confirming these responses using northern and western blot analysis. Yeast two hybrid analysis has also been useful in demonstrating interacting proteins. One protein, which interacts with DIR1 is similar to murine UIP28, a RING finger protein which interacts with the ubiquitin conjugating enzyme, UbcM4. Interestingly, the ubiquitin (Ub)/proteosome pathway regulates many cellular processes including apoptosis, cell cycle progression, stress responses, development and transcriptional regulation. Further characterisation of these downstream genes and interacting proteins will allow us to:- i) dissect the cellular pathways involved in adaptation to oxidative and genotoxic stress ii) elucidate the mechanisms involved in many disease pathologies iii) identify new

  14. High linear-energy-transfer radiation can overcome radioresistance of glioma stem-like cells to low linear-energy-transfer radiation.

    Science.gov (United States)

    Hirota, Yuki; Masunaga, Shin-Ichiro; Kondo, Natsuko; Kawabata, Shinji; Hirakawa, Hirokazu; Yajima, Hirohiko; Fujimori, Akira; Ono, Koji; Kuroiwa, Toshihiko; Miyatake, Shin-Ichi

    2014-01-01

    Ionizing radiation is applied as the standard treatment for glioblastoma multiforme (GBM). However, radiotherapy remains merely palliative, not curative, because of the existence of glioma stem cells (GSCs), which are regarded as highly radioresistant to low linear-energy-transfer (LET) photons. Here we analyzed whether or not high-LET particles can overcome the radioresistance of GSCs. Glioma stem-like cells (GSLCs) were induced from the GBM cell line A172 in stem cell culture medium. The phenotypes of GSLCs and wild-type cells were confirmed using stem cell markers. These cells were irradiated with (60)Co gamma rays or reactor neutron beams. Under neutron-beam irradiation, high-LET proton particles can be produced through elastic scattering or nitrogen capture reaction. Radiosensitivity was assessed by a colony-forming assay, and the DNA double-strand breaks (DSBs) were assessed by a histone gamma-H2AX focus detection assay. In stem cell culture medium, GSLCs could form neurosphere-like cells and express neural stem cell markers (Sox2 and Musashi) abundantly in comparison with their parental cells. GSLCs were significantly more radioresistant to gamma rays than their parental cells, but neutron beams overcame this resistance. There were significantly fewer gamma-H2AX foci in the A172 GSLCs 24 h after irradiation with gamma rays than in their parental cultured cells, while there was no apparent difference following neutron-beam irradiation. High-LET radiation can overcome the radioresistance of GSLCs by producing unrepairable DNA DSBs. High-LET radiation therapy might have the potential to overcome GBM's resistance to X-rays in a clinical setting.

  15. High linear-energy-transfer radiation can overcome radioresistance of glioma stem-like cells to low linear-energy-transfer radiation

    International Nuclear Information System (INIS)

    Hirota, Yuki; Kawabata, Shinji; Kuroiwa, Toshihiko; Miyatake, Shin-ichi; Masunaga, Shin-ichiro; Kondo, Natsuko; Ono, Koji; Hirakawa, Hirokazu; Yajima, Hirohiko; Fujimori, Akira

    2014-01-01

    Ionizing radiation is applied as the standard treatment for glioblastoma multiforme (GBM). However, radiotherapy remains merely palliative, not curative, because of the existence of glioma stem cells (GSCs), which are regarded as highly radioresistant to low linear-energy-transfer (LET) photons. Here we analyzed whether or not high-LET particles can overcome the radioresistance of GSCs. Glioma stem-like cells (GSLCs) were induced from the GBM cell line A172 in stem cell culture medium. The phenotypes of GSLCs and wild-type cells were confirmed using stem cell markers. These cells were irradiated with 60 Co gamma rays or reactor neutron beams. Under neutron-beam irradiation, high-LET proton particles can be produced through elastic scattering or nitrogen capture reaction. Radiosensitivity was assessed by a colony-forming assay, and the DNA double-strand breaks (DSBs) were assessed by a histone gamma-H2AX focus detection assay. In stem cell culture medium, GSLCs could form neurosphere-like cells and express neural stem cell markers (Sox2 and Musashi) abundantly in comparison with their parental cells. GSLCs were significantly more radioresistant to gamma rays than their parental cells, but neutron beams overcame this resistance. There were significantly fewer gamma-H2AX foci in the A172 GSLCs 24 h after irradiation with gamma rays than in their parental cultured cells, while there was no apparent difference following neutron-beam irradiation. High-LET radiation can overcome the radioresistance of GSLCs by producing unrepairable DNA DSBs. High-LET radiation therapy might have the potential to overcome GBM's resistance to X-rays in a clinical setting. (author)

  16. USP1 targeting impedes GBM growth by inhibiting stem cell maintenance and radioresistance.

    Science.gov (United States)

    Lee, Jin-Ku; Chang, Nakho; Yoon, Yeup; Yang, Heekyoung; Cho, Heejin; Kim, Eunhee; Shin, Yongjae; Kang, Wonyoung; Oh, Young Taek; Mun, Gyeong In; Joo, Kyeung Min; Nam, Do-Hyun; Lee, Jeongwu

    2016-01-01

    Clinical benefits from standard therapies against glioblastoma (GBM) are limited in part due to intrinsic radio- and chemoresistance of GBM and inefficient targeting of GBM stem-like cells (GSCs). Novel therapeutic approaches that overcome treatment resistance and diminish stem-like properties of GBM are needed. We determined the expression levels of ubiquitination-specific proteases (USPs) by transcriptome analysis and found that USP1 is highly expressed in GBM. Using the patient GBM-derived primary tumor cells, we inhibited USP1 by shRNA-mediated knockdown or its specific inhibitor pimozide and evaluated the effects on stem cell marker expression, proliferation, and clonogenic growth of tumor cells. USP1 was highly expressed in gliomas relative to normal brain tissues and more preferentially in GSC enrichment marker (CD133 or CD15) positive cells. USP1 positively regulated the protein stability of the ID1 and CHEK1, critical regulators of DNA damage response and stem cell maintenance. Targeting USP1 by RNA interference or treatment with a chemical USP1 inhibitor attenuated clonogenic growth and survival of GSCs and enhanced radiosensitivity of GBM cells. Finally, USP1 inhibition alone or in combination with radiation significantly prolonged the survival of tumor-bearing mice. USP1-mediated protein stabilization promotes GSC maintenance and treatment resistance, thereby providing a rationale for USP1 inhibition as a potential therapeutic approach against GBM. © The Author(s) 2015. Published by Oxford University Press on behalf of the Society for Neuro-Oncology. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  17. Prognostic factors for outcomes after whole-brain irradiation of brain metastases from relatively radioresistant tumors: a retrospective analysis

    Directory of Open Access Journals (Sweden)

    Schild Steven E

    2010-10-01

    Full Text Available Abstract Background This study investigated potential prognostic factors in patients treated with whole-brain irradiation (WBI alone for brain metastases from relatively radioresistant tumors such as malignant melanoma, renal cell carcinoma, and colorectal cancer. Additionally, a potential benefit from escalating the radiation dose was investigated. Methods Data from 220 patients were retrospectively analyzed for overall survival and local control. Nine potential prognostic factors were evaluated: tumor type, WBI schedule, age, gender, Karnofsky performance score, number of brain metastases, extracerebral metastases, interval from diagnosis of cancer to WBI, and recursive partitioning analysis (RPA class. Results Survival rates at 6 and 12 months were 32% and 19%, respectively. In the multivariate analysis, WBI doses >30 Gy (p = 0.038, KPS ≥70 (p Conclusions Improved outcomes were associated with WBI doses >30 Gy, better performance status, fewer brain metastases, lack of extracerebral metastases, and lower RPA class. Patients receiving WBI alone appear to benefit from WBI doses >30 Gy. However, such a benefit is limited to RPA class 1 or 2 patients.

  18. Interactions of checkpoint-genes RAD9, RAD17, RAD24 and RAD53 determining radioresistance of Yeast Saccharomyces Cerevisiae

    International Nuclear Information System (INIS)

    Koltovaya, N.A.; Nikulushkina, Yu.V.; Roshchina, M.P.; Devin, A.B.

    2007-01-01

    The mechanisms of genetic control of progress through the division cell cycle (checkpoint-control) in yeast Saccharomyces cerevisiae have been studied intensively. To investigate the role of checkpoint-genes RAD9, RAD17, RAD24, RAD53 in cell radioresistance we have investigated cell sensitivity of double mutants to γ-ray. Double mutants involving various combinations with rad9Δ show epistatic interactions, i.e. the sensitivity of the double mutants to γ-ray was no greater than that of more sensitive of the two single mutants. This suggests that all these genes govern the same pathway. This group of genes was named RAD9-epistasis group. It is interesting to note that the genes RAD9 and RAD53 have positive effect but RAD17 and RAD24 have negative effect on radiosensitivity of yeast cells. Interactions between mutations may differ depending on the agent γ-ray or UV-light, for example mutations rad9Δ and rad24Δ show additive effect for γ-ray and epistatic effect for UV-light

  19. Prenatal diagnosis of ataxia-telangiectasia and Nijmegen Breakage Syndrome by the assay of radioresistant DNA synthesis

    International Nuclear Information System (INIS)

    Kleijer, W.J.; Kraan, M. van der; Los, F.J.; Jaspers, N.G.J.

    1994-01-01

    Prenatal diagnosis was performed in 16 pregnancies at risk of ataxia-telangiectasia (A-T) or Nijmegen Breakage Syndrome (NBS). Radioresistant DNA synthesis (RDS) was investigated in cultured chorionic villus (CV) cells and/or amniotic fluid (AF) cells. In four pregnancies, an affected foetus was diagnosed with increased RDS in cultured CV cells. In three of the four cases confirmation of the diagnosis was obtained by analysis of AF cells and/or skin fibroblasts from the foetus cultured after termination of the pregnancy; in the fourth case a fibroblast culture from the aborted foetus failed. In one case, only AF cells could be analysed in a late stage of pregnancy; pregnancy was terminated due to intermediate/equivocal results but the foetus fibroblasts showed normal RDS. Normal RDS was demonstrated in the other 11 pregnancies at 25% risk either by analysis of CB cells (nine cases) or of AF cells (two cases). In some cases the (normal) results on the CV cells were corroborated by subsequent analysis of Af cells. The results suggest that RDS analysis of CV cells allows reliable prenatal diagnosis of A-T/NBS. However, amniocentesis may be necessary to confirm normal results on CV cells if the foetus is female (because of the risk of maternal cell contamination) or in the rare case of equivocal results. (author)

  20. 31P NMR spectroscopy and HbO2 cryospectrophotometry in prediction of tumor radioresistance caused by hypoxia.

    Science.gov (United States)

    Rofstad, E K; DeMuth, P; Fenton, B M; Ceckler, T L; Sutherland, R M

    1989-04-01

    The aim of this study was to search for possible relationships between the fraction of radiobiologically hypoxic cells in tumors and their 31P NMR spectral parameters and intracapillary HbO2 saturations. Four different tumor lines, two murine sarcomas (KHT, RIF-1) and two human ovarian carcinoma xenografts (MLS, OWI), were used. When tumor volume increased from about 200 mm3 to about 2000 mm3, hypoxic fraction increased from 12 to 23% for the KHT line, from 0.9 to 1.7% for the RIF-1 line, and from 9 to 28% for the MLS line. The OWI line showed similar hypoxic fractions at 200 (17%) and 2000 mm3 (15%). Tumor bioenergetic status decreased, that is, the inorganic phosphate (Pi) resonance increased and the phosphocreatine (PCr) and nucleoside triphosphate beta (NTP beta) resonances decreased, with increasing tumor volume for the KHT, RIF-1, and MLS lines, whereas the OWI line did not show any changes in the 31P NMR spectral parameters during tumor growth. Similarly, tumor HbO2 saturation status, that is, the fraction of vessels with HbO2 saturation above 30%, decreased with increasing tumor volume for the KHT, RIF-1, and MLS lines, but remained unchanged during tumor growth for the OWI line. Although the data indicated a relationship between hypoxic fraction and tumor bioenergetic status as well as tumor HbO2 saturation status within a specific line during tumor growth, there was no correlation between hypoxic fraction and tumor bioenergetic status or tumor HbO2 saturation status across the four tumor lines. This may have occurred because cell survival time under hypoxic stress as well as fraction of non-clonogenic, but metabolically active hypoxic cells differed among the tumor lines. This indicates that 31P NMR spectroscopy and HbO2 cryospectrophotometry data have to be supplemented with other data to be useful in prediction of tumor radioresistance caused by hypoxia.

  1. Differential Bystander Signaling Between Radioresistant Chondrosarcoma Cells and Fibroblasts After X-Ray, Proton, Iron Ion and Carbon Ion Exposures

    Energy Technology Data Exchange (ETDEWEB)

    Wakatsuki, Masaru, E-mail: wa@mbe.nifty.com [Research Center for Charged Particle Therapy, National Institute of Radiological Sciences, Chiba (Japan); Department of Radiation Oncology, Massachusetts General Hospital/Harvard Medical School, Boston, Massachusetts (United States); Magpayo, Nicole; Kawamura, Hidemasa; Held, Kathryn D. [Department of Radiation Oncology, Massachusetts General Hospital/Harvard Medical School, Boston, Massachusetts (United States)

    2012-09-01

    Purpose: Chondrosarcoma is well known as a radioresistant tumor, but the mechanisms underlying that resistance are still unclear. The bystander effect is well documented in the field of radiation biology. We investigated the bystander response induced by X-rays, protons, carbon ions, and iron ions in chondrosarcoma cells using a transwell insert co-culture system that precludes physical contact between targeted and bystander cells. Methods and Materials: Human chondrosarcoma cells were irradiated with 0.1-, 0.5-, 1-, and 2-Gy X-rays, protons, carbon ions or iron ions using a transwell insert co-culture system. Formation of micronuclei and p53 binding protein 1 staining in bystander and irradiated cells were analyzed and bystander signaling between mixed cultures of chondrosarcoma cells, and normal human skin fibroblasts was investigated. Results: In this study, we show that the fraction of cells with DNA damages in irradiated chondrosarcoma cells showed dose-dependent increases with all beams. However, the fraction of cells with DNA damages in all bystander chondrosarcoma cells did not show any change from the levels in control cells. In the bystander signaling between mixed cultures of chondrosarcoma cells and fibroblasts, the amount of micronucleus formation in all bystander chondrosarcoma cells co-cultured with irradiated fibroblasts were the same as the levels for control cells. However, all bystander fibroblasts co-cultured with irradiated chondrosarcoma cells showed significant increases in the fraction of micronucleated cells compared to the rate of control cells. Conclusions: We conclude that chondrosarcoma cells in the transwell insert co-culture system could release bystander stimulations but could not develop bystander responses.

  2. Differential Bystander Signaling Between Radioresistant Chondrosarcoma Cells and Fibroblasts After X-Ray, Proton, Iron Ion and Carbon Ion Exposures

    International Nuclear Information System (INIS)

    Wakatsuki, Masaru; Magpayo, Nicole; Kawamura, Hidemasa; Held, Kathryn D.

    2012-01-01

    Purpose: Chondrosarcoma is well known as a radioresistant tumor, but the mechanisms underlying that resistance are still unclear. The bystander effect is well documented in the field of radiation biology. We investigated the bystander response induced by X-rays, protons, carbon ions, and iron ions in chondrosarcoma cells using a transwell insert co-culture system that precludes physical contact between targeted and bystander cells. Methods and Materials: Human chondrosarcoma cells were irradiated with 0.1-, 0.5-, 1-, and 2-Gy X-rays, protons, carbon ions or iron ions using a transwell insert co-culture system. Formation of micronuclei and p53 binding protein 1 staining in bystander and irradiated cells were analyzed and bystander signaling between mixed cultures of chondrosarcoma cells, and normal human skin fibroblasts was investigated. Results: In this study, we show that the fraction of cells with DNA damages in irradiated chondrosarcoma cells showed dose-dependent increases with all beams. However, the fraction of cells with DNA damages in all bystander chondrosarcoma cells did not show any change from the levels in control cells. In the bystander signaling between mixed cultures of chondrosarcoma cells and fibroblasts, the amount of micronucleus formation in all bystander chondrosarcoma cells co-cultured with irradiated fibroblasts were the same as the levels for control cells. However, all bystander fibroblasts co-cultured with irradiated chondrosarcoma cells showed significant increases in the fraction of micronucleated cells compared to the rate of control cells. Conclusions: We conclude that chondrosarcoma cells in the transwell insert co-culture system could release bystander stimulations but could not develop bystander responses.

  3. Role of endogeneous thiols in the determination of radio-resistance of E. coli B culture in different phases of its growth

    Energy Technology Data Exchange (ETDEWEB)

    Konstantinova, M M [AN SSSR, Moscow. Inst. Biologii Razvitiya

    1975-05-01

    An investigation was made of the link between the radioresistance of various stages of development of a culture of E. coli B with the level of sulfhydryl groups in the cells at each stage. The analysis was carried out by comparing the content of sulfhydryl groups in the cells, with their viability after irradiation and by determining the effectiveness of radio-protective and radio-sensitizing agents on a culture of various ages. It was shown that the thiols are the factor that determines the variation in radiosensitivity of a culture of E. coli B in the logarithmic and stationary phases of growth.

  4. Comparison of SDR presumed by AAMI and the radio-resistance distribution of the microbiological populations exist on the Turkish made single use syringes

    International Nuclear Information System (INIS)

    Konac, T.; Siyakus, G.; Basguel, M.; Uenal, Z.

    2001-01-01

    The concept of radiation sterilization of medical devices was introduced in Turkey 10 years ago through the irradiation facilities in Ankara and Istanbul. It has been preferred by international community due to technological advantages,such as freedom from chemical residues, safer sterility assurance, etc.. This technology is regulated by ISO 11137 (1), EN 552 (2) standards and their references. The scope of this study was to compare the radio-resistance distribution of the microbial population on the Turkish single use syringes and SDR

  5. Transition in Survival From Low-Dose Hyper-Radiosensitivity to Increased Radioresistance Is Independent of Activation of ATM SER1981 Activity

    International Nuclear Information System (INIS)

    Krueger, Sarah A.; Collis, Spencer J.; Joiner, Michael C.; Wilson, George D.; Marples, Brian

    2007-01-01

    Purpose: The molecular basis of low-dose hyper-radiosensitivity (HRS) is only partially understood. The aim of this study was to define the roles of ataxia telangiectasia mutated (ATM) activity and the downstream ATM-dependent G 2 -phase cell cycle checkpoint in overcoming HRS and triggering radiation resistance. Methods and Materials: Survival was measured using a high-resolution clonogenic assay. ATM Ser1981 activation was measured by Western blotting. The role of ATM was determined in survival experiments after molecular (siRNA) and chemical (0.4 mM caffeine) inhibition and chemical (20 μg/mL chloroquine, 15 μM genistein) activation 4-6 h before irradiation. Checkpoint responsiveness was assessed in eight cell lines of differing HRS status using flow cytometry to quantify the progression of irradiated (0-2 Gy) G 2 -phase cells entering mitosis, using histone H3 phosphorylation analysis. Results: The dose-response pattern of ATM activation was concordant with the transition from HRS to radioresistance. However, ATM activation did not play a primary role in initiating increased radioresistance. Rather, a relationship was discovered between the function of the downstream ATM-dependent early G 2 -phase checkpoint and the prevalence and overcoming of HRS. Four cell lines that exhibited HRS failed to show low-dose ( 2 -phase checkpoint. These data suggest that clinical exploitation of HRS could be achieved by combining radiotherapy with chemotherapeutic agents that modulate this cell cycle checkpoint

  6. Caveolae-Mediated Endocytosis Is Critical for Albumin Cellular Uptake and Response to Albumin-Bound Chemotherapy.

    Science.gov (United States)

    Chatterjee, Moumita; Ben-Josef, Edgar; Robb, Ryan; Vedaie, Marall; Seum, Star; Thirumoorthy, Krishnan; Palanichamy, Kamalakannan; Harbrecht, Matthew; Chakravarti, Arnab; Williams, Terence M

    2017-11-01

    Nab-paclitaxel, a nanoparticle conjugate of paclitaxel to human albumin, exhibits efficacy in pancreatic cancer, non-small cell lung cancer and breast cancer. However, there is a lack of predictive biomarkers to identify patients who might benefit most from its administration. This study addresses this gap in knowledge by identifying that caveolin-1 (Cav-1) is a candidate mechanism-based biomarker. Caveolae are small membrane invaginations important for transendothelial albumin uptake. Cav-1, the principal structural component of caveolae, is overexpressed in the cancers noted above that respond to nab-paclitaxel. Thus, we hypothesized that Cav-1 may be critical for albumin uptake in tumors and perhaps determine their response to this drug. Cav-1 protein levels correlated positively with nab-paclitaxel sensitivity. RNAi-mediated attenuation of Cav-1 expression reduced uptake of albumin and nab-paclitaxel in cancer cells and rendered them resistant to nab-paclitaxel-induced apoptosis. Conversely, Cav-1 overexpression enhanced sensitivity to nab-paclitaxel. Selection for cellular resistance to nab-paclitaxel in cell culture correlated with a loss of Cav-1 expression. In mouse xenograft models, cancer cells, where Cav-1 was attenuated, exhibited resistance to the antitumor effects of nab-paclitaxel therapy. Overall, our findings suggest Cav-1 as a predictive biomarker for the response to nab-paclitaxel and other albumin-based cancer therapeutic drugs. Cancer Res; 77(21); 5925-37. ©2017 AACR . ©2017 American Association for Cancer Research.

  7. PGE2 mediates EGFR internalization and nuclear translocation via caveolin endocytosis promoting its transcriptional activity and proliferation in human NSCLC cells.

    Science.gov (United States)

    Bazzani, Lorenzo; Donnini, Sandra; Giachetti, Antonio; Christofori, Gerhard; Ziche, Marina

    2018-03-13

    Prostaglandin E 2 (PGE 2 ) contributes to tumor progression by promoting cancer cell growth, invasion and by creating a favorable pro-tumor microenvironment. PGE 2 has been reported to transactivate and internalize into the nucleus receptor tyrosine kinases such as Epidermal growth factor receptor (EGFR), thereby supporting tumor progression. Here we demonstrate that in non-small cell lung carcinoma (NSCLC) cells, PGE 2 induces EGFR nuclear translocation via different dynamin-dependent endocytic pathways, promotes the formation of an EGFR-STAT3 complex, affects nuclear EGFR target gene expression and mediates tumor cell proliferation. Indeed, we find that PGE 2 induces EGFR internalization and consequent nuclear import through Clathrin- and Caveolin-mediated endocytosis and through the interaction of EGFR with Importin β1. Within the nucleus, EGFR forms a complex with STAT3, an event blocked by ablation of Clathrin Heavy Chain or Caveolin-1. The combination of EGF and PGE 2 prolongs nuclear EGFR transcriptional activity manifested by the upregulation of CCND1 , PTGS2 , MYC and NOS2 mRNA levels and potentiates nuclear EGFR-induced NSCLC cell proliferation. Additionally, NSCLC patients with high expression of a nuclear EGFR gene signature display shorter survival times than those with low expression, thus showing a putative correlation between nuclear EGFR and poor prognosis in NSCLC. Together, our findings indicate a complex mechanism underlying PGE 2 -induced EGF/EGFR signaling and transcriptional control, which plays a key role in cancer progression.

  8. Focal-adhesion targeting links caveolin-1 to a Rac1-degradation pathway

    NARCIS (Netherlands)

    Nethe, Micha; Anthony, Eloise C.; Fernandez-Borja, Mar; dee, Rob; Geerts, Dirk; Hensbergen, Paul J.; Deelder, André M.; Schmidt, Gudula; Hordijk, Peter L.

    2010-01-01

    Directional cell migration is crucially dependent on the spatiotemporal control of intracellular signalling events. These events regulate polarized actin dynamics, resulting in protrusion at the front of the cell and contraction at the rear. The actin cytoskeleton is regulated through signalling by

  9. Caveolae, caveolin-1 and cavin-1: Emerging roles in pulmonary hypertension.

    Science.gov (United States)

    Chettimada, Sukrutha; Yang, Jincheng; Moon, Hyung-Geun; Jin, Yang

    2015-07-28

    Caveolae are flask-shaped invaginations of cell membrane that play a significant structural and functional role. Caveolae harbor a variety of signaling molecules and serve to receive, concentrate and transmit extracellular signals across the membrane. Caveolins are the main structural proteins residing in the caveolae. Caveolins and another category of newly identified caveolae regulatory proteins, named cavins, are not only responsible for caveolae formation, but also interact with signaling complexes in the caveolae and regulate transmission of signals across the membrane. In the lung, two of the three caveolin isoforms, i.e ., cav-1 and -2, are expressed ubiquitously. Cavin protein family is composed of four proteins, named cavin-1 (or PTRF for polymerase Ⅰ and transcript release factor), cavin-2 (or SDPR for serum deprivation protein response), cavin-3 (or SRBC for sdr-related gene product that binds to-c-kinase) and cavin-4 (or MURC for muscle restricted coiled-coiled protein or cavin-4). All the caveolin and cavin proteins are essential regulators for caveolae dynamics. Recently, emerging evidence suggest that caveolae and its associated proteins play crucial roles in development and progression of pulmonary hypertension. The focus of this review is to outline and discuss the contrast in alteration of cav-1 (cav-1),-2 and cavin-1 (PTRF) expression and downstream signaling mechanisms between human and experimental models of pulmonary hypertension.

  10. Radioresistance of inorganic glasses

    International Nuclear Information System (INIS)

    Vorob'ev, A.A.; Zavadovskaya, E.K.; Fedorov, B.V.; Starodubtsev, V.A.

    1977-01-01

    Regularities are considered in the variation of properties of glass due to irradiations. On the basis of previous theoretical statements and experimental investigations, it is inferred that the irradiation resistance of glasses of the same type, synthesis conditions, content of impurities and amount of imperfections, is a function of the ''element-oxygen'' bond energy. The irradiation resistance depends on the number and the nature of glass structure imperfections. The averaged level of bonding forces is indicative of the glass formation temperature; the imperfections in glasses are formed in structure elements whose amount predominates as compared to the others. Electric charges which accumulate on the crack surface tend to increase its size, thus lessening even further the electric strength of the dielectric. The greater the irradiation time, the greater the number of irradiation imperfections causing a drop in the electric strength of glass. When choosing a glass for service in a radiation field, it is necessary to select those of a highest temperature of glass formation and with a least amount of imperfections

  11. INPP4B-mediated tumor resistance is associated with modulation of glucose metabolism via hexokinase 2 regulation in laryngeal cancer cells

    Energy Technology Data Exchange (ETDEWEB)

    Min, Joong Won [Division of Radiation Cancer Research, Korea Institute of Radiological and Medical Sciences, Seoul (Korea, Republic of); Kim, Kwang Il [Molecular Imaging Research Center, Korea Institute of Radiological and Medical Sciences, Seoul (Korea, Republic of); Kim, Hyun-Ah; Kim, Eun-Kyu; Noh, Woo Chul [Department of Surgery, Korea Cancer Center Hospital, Korea Institute of Radiological and Medical Sciences, Seoul (Korea, Republic of); Jeon, Hong Bae [Biomedical Research Institute, MEDIPOST Co., Ltd., Seoul (Korea, Republic of); Cho, Dong-Hyung [Graduate School of East-West Medical Science, Kyung Hee University, Gyeonggi-do (Korea, Republic of); Oh, Jeong Su [Department of Genetic Engineering, Sungkyunkwan University, Suwon (Korea, Republic of); Park, In-Chul; Hwang, Sang-Gu [Division of Radiation Cancer Research, Korea Institute of Radiological and Medical Sciences, Seoul (Korea, Republic of); Kim, Jae-Sung, E-mail: jaesung@kirams.re.kr [Division of Radiation Cancer Research, Korea Institute of Radiological and Medical Sciences, Seoul (Korea, Republic of)

    2013-10-11

    Highlights: •HIF-1α-regulated INPP4B enhances glycolysis. •INPP4B regulates aerobic glycolysis by inducing HK2 via Akt-mTOR pathway. •Blockage of INPP4B and HK2 sensitizes radioresistant laryngeal cancer cells to radiation and anticancer drug. •INPP4B is associated with HK2 in human laryngeal cancer tissues. -- Abstract: Inositol polyphosphate 4-phosphatase type II (INPP4B) was recently identified as a tumor resistance factor in laryngeal cancer cells. Herein, we show that INPP4B-mediated resistance is associated with increased glycolytic phenotype. INPP4B expression was induced by hypoxia and irradiation. Intriguingly, overexpression of INPP4B enhanced aerobic glycolysis. Of the glycolysis-regulatory genes, hexokinase 2 (HK2) was mainly regulated by INPP4B and this regulation was mediated through the Akt-mTOR pathway. Notably, codepletion of INPP4B and HK2 markedly sensitized radioresistant laryngeal cancer cells to irradiation or anticancer drug. Moreover, INPP4B was significantly associated with HK2 in human laryngeal cancer tissues. Therefore, these results suggest that INPP4B modulates aerobic glycolysis via HK2 regulation in radioresistant laryngeal cancer cells.

  12. Intercultural Mediation

    OpenAIRE

    Dragos Marian Radulescu; Denisa Mitrut

    2012-01-01

    The Intercultural Mediator facilitates exchanges between people of different socio-cultural backgrounds and acts as a bridge between immigrants and national and local associations, health organizations, services and offices in order to foster integration of every single individual. As the use mediation increases, mediators are more likely to be involved in cross-cultural mediation, but only the best mediators have the opportunity to mediate cross border business disputes or international poli...

  13. The effect of radiosensitizers on the survival response of hypoxic mammalian cells: The low X-ray dose region, hypersensitivity and induced radioresistance

    International Nuclear Information System (INIS)

    Skov, K.A.; MacPhail, H.S.; Marples, B.

    1994-01-01

    It has been shown previously that the extent of chemical modification of the hypoxic radiation response is dependent on dose. Some types of sensitizer are more effective at low doses (to 4 Gy) than at higher doses. Since such drugs are possible adjuvants to radiotherapy, the mechanisms responsible for the variable response at clinical doses are summarized, and the effects of cisplatin and buthionine sulfoximine on the purported induced response to radiation in hypoxic cells are presented. Cisplatin at a low, nontoxic concentration (1 μM) appears to abolish the increased radioresistant portion of the survival response. A role for high-mobility-group protein binding by platinum drugs is hypothesized to explain their interaction with radiation, and conversely, it is suggested that the heretofore unexplained different behavior of certain hypoxic sensitizers at low doses could be, at least in part, an effect on the induction of resistance. 36 refs., 2 figs

  14. HIF-1α inhibition by siRNA or chetomin in human malignant glioma cells: effects on hypoxic radioresistance and monitoring via CA9 expression

    Directory of Open Access Journals (Sweden)

    Bache Matthias

    2010-11-01

    Full Text Available Abstract Background Hypoxia induces activation of the HIF-1 pathway and is an essential characteristic of malignant gliomas. Hypoxia has been linked to tumor progression, therapy resistance and poor prognosis. However, little is known about the impact of HIF-1α inhibition on radioresistance of malignant glioma. Methods In this study, we investigated the effects of the inhibition of HIF-1α on cell survival and radiosensitivity in U251MG and U343MG glioma cells, using two different strategies. HIF-1α inhibition was achieved by siRNA targeting of HIF-1α or via chetomin, a disruptor of interactions between HIF-1α and p300. The inhibition of the HIF-1 pathway was monitored by quantitative real-time PCR and Western blot analyses of the expression levels of HIF-1α and CA9. CA9 expression was investigated as a potential indicator of the efficacy of HIF-1 inhibition and the resulting radiosensitivity of malignant glioma cell lines was determined by clonogenic assay after irradiation under normoxic (2-10 Gy or hypoxic (2-15 Gy conditions. Results Although siRNA and chetomin show distinct modes of action, both attenuated the hypoxia-induced radioresistance of malignant glioma cell lines U251MG (DMF10: 1.35 and 1.18 and U343MG (DMF10: 1.78 and 1.48. However, siRNA and chetomin showed diverse effects on radiosensitivity under normoxic conditions in U251MG (DMF10: 0.86 and 1.35 and U343MG (DMF10: 1.33 and 1.02 cells. Conclusions Results from this in vitro study suggest that inhibition of HIF-1α is a promising strategy to sensitize human malignant gliomas to radiotherapy and that CA9 could serve as an indicator of effective HIF-1-related radiosensitization.

  15. Daoy medulloblastoma cells that express CD133 are radioresistant relative to CD133- cells, and the CD133+ sector is enlarged by hypoxia

    International Nuclear Information System (INIS)

    Blazek, Ed R.; Foutch, Jennifer L.; Maki, Guitta

    2007-01-01

    Purpose: Primary medulloblastoma and glioblastoma multiforme tumor cells that express the surface marker CD133 are believed to be enriched for brain tumor stem cells because of their unique ability to initiate or reconstitute tumors in immunodeficient mice. This study sought to characterize the radiobiological properties and marker expression changes of CD133+ vs. CD133- cells of an established medulloblastoma cell line. Methods and Materials: Daoy and D283 Med cell lines were stained with fluorescently labeled anti-CD133 antibody and sorted into CD133+ and CD133- populations. The effect of oxygen (2% vs. 20%) on CD133 expression was measured. Both populations were analyzed for marker stability, cell cycle distribution, and radiosensitivity. Results: CD133+ Daoy cells restored nearly native CD133+ and CD133- populations within 18 days, whereas CD133- cells remained overwhelmingly CD133-. Culturing Daoy cells in 2% oxygen rather than the standard 20% oxygen increased their CD133 expression 1.6-fold. CD133+ Daoy cells were radioresistant via the β-parameter of the linear-quadratic model relative to CD133- Daoy cells, although their α-parameters and cell cycle distributions were identical. Conclusions: Restoration of the original CD133+ and CD133- populations from CD133+ Daoy cells in serum is further evidence that CD133+ cells are functionally distinct from CD133- cells. The radioresistance of CD133+ compared with CD133- Daoy cells is consistent with better repair of sublethal damage. Enlargement of the CD133+ sector is a new feature of the hypoxic response

  16. DNA-mediated gene transfer into ataxia-telangiectasia cells

    International Nuclear Information System (INIS)

    Crescenzi, M.; Pulciani, S.; Carbonari, M.; Tedesco, L.; Russo, G.; Gaetano, C.; Fiorilli, M.

    1986-01-01

    The complete description of the genetic lesion(s) underlying the AT mutation might, therefore, highlight not only a DNA-repair pathwa, but also an important aspect of the physiology of lymphocytes. DNA-mediated gene transfer into eukaryotic cells has proved a powerful tool for the molecular cloning of certain mammalian genes. The possibility to clone a given gene using this technology depends, basically, on the availability of a selectable marker associated with the expression of the transfected gene in the recipient cell. Recently, a human DNA repair gene has been cloned in CHO mutant cells by taking advantage of the increased resistance to ultraviolet radiation of the transformants. As a preliminary step toward the molecular cloning of the AT gene(s), the authors have attempted to confer radioresistance to AT cells by transfection with normal human DNA

  17. Mediation Analysis with Multiple Mediators.

    Science.gov (United States)

    VanderWeele, T J; Vansteelandt, S

    2014-01-01

    Recent advances in the causal inference literature on mediation have extended traditional approaches to direct and indirect effects to settings that allow for interactions and non-linearities. In this paper, these approaches from causal inference are further extended to settings in which multiple mediators may be of interest. Two analytic approaches, one based on regression and one based on weighting are proposed to estimate the effect mediated through multiple mediators and the effects through other pathways. The approaches proposed here accommodate exposure-mediator interactions and, to a certain extent, mediator-mediator interactions as well. The methods handle binary or continuous mediators and binary, continuous or count outcomes. When the mediators affect one another, the strategy of trying to assess direct and indirect effects one mediator at a time will in general fail; the approach given in this paper can still be used. A characterization is moreover given as to when the sum of the mediated effects for multiple mediators considered separately will be equal to the mediated effect of all of the mediators considered jointly. The approach proposed in this paper is robust to unmeasured common causes of two or more mediators.

  18. p53-independent early and late apoptosis is mediated by ceramide after exposure of tumor cells to photon or carbon ion irradiation

    International Nuclear Information System (INIS)

    Alphonse, Gersende; Maalouf, Mira; Battiston-Montagne, Priscillia; Ardail, Dominique; Beuve, Michaël; Rousson, Robert; Taucher-Scholz, Gisela; Fournier, Claudia; Rodriguez-Lafrasse, Claire

    2013-01-01

    To determine whether ceramide is responsible for the induction of p53-independent early or late apoptosis in response to high- and low-Linear-Energy-Transfer (LET) irradiation. Four cell lines displaying different radiosensitivities and p53-protein status were irradiated with photons or 33.4 or 184 keV/μm carbon ions. The kinetics of ceramide production was quantified by fluorescent microscopy or High-Performance-Liquid-Chromatogaphy and the sequence of events leading to apoptosis by flow cytometry. Regardless of the p53-status, both low and high-LET irradiation induced an early ceramide production in radiosensitive cells and late in the radioresistant. This production strongly correlated with the level of early apoptosis in radiosensitive cells and delayed apoptosis in the radioresistant ones, regardless of radiation quality, tumor type, radiosensitivity, or p53-status. Inhibition of caspase activity or ceramide production showed that, for both types of radiation, ceramide is essential for the initiation of early apoptosis in radiosensitive cells and late apoptosis following mitotic catastrophe in radioresistant cells. Ceramide is a determining factor in the onset of early and late apoptosis after low and high-LET irradiation and is the mediator of the p53-independent-apoptotic pathway. We propose that ceramide is the molecular bridge between mitotic catastrophe and the commitment phase of delayed apoptosis in response to irradiation

  19. Mediation Analysis with Multiple Mediators

    OpenAIRE

    VanderWeele, T.J.; Vansteelandt, S.

    2014-01-01

    Recent advances in the causal inference literature on mediation have extended traditional approaches to direct and indirect effects to settings that allow for interactions and non-linearities. In this paper, these approaches from causal inference are further extended to settings in which multiple mediators may be of interest. Two analytic approaches, one based on regression and one based on weighting are proposed to estimate the effect mediated through multiple mediators and the effects throu...

  20. The role of Rad 51 protein in radioresistance of spheroid model of Du 145 prostate carcinoma cell line

    International Nuclear Information System (INIS)

    Taghizadeh, M.; Khoei, S.; Nikoofar, A. R.; Ghamsari, L.; Goliaei, B.

    2009-01-01

    Rad 51 is a protein with critical role in double strand break repair. Down-regulation of this protein has a significant effect in radiosensitivity of some cell lines like prostate carcinoma. Compared to monolayer cell culture model, the spheroids are more resistant to radiation. The aim of the current study was to determine the Rad 51 protein level in Du 145 spheroids, and monolayer cells before and after exposure to gamma irradiation. Materials and Methods: In the present study, western blot was used to determine the level of Rad 51 protein in Du 145 cell line grown as monolayer and spheroid. Results: Western blot analysis showed that in the spheroid cells, Rad 51 had an elevated level before and after radiation in comparison with monolayer cells. Higher doses of radiation induced elevated expression of Rad 51 protein in both culture models.The level of at protein after exposure to gamma rays had been time-dependent. Conclusion: Rad 51 might act as a mediator of radiation resistance in tumor cells. Repression of Rad 51 activity could be a prominent strategy to overcome radiation resistance of tumors.

  1. Complex Mediation

    DEFF Research Database (Denmark)

    Bødker, Susanne; Andersen, Peter Bøgh

    2005-01-01

    This article has its starting point in a large number of empirical findings regarding computer-mediated work. These empirical findings have challenged our understanding of the role of mediation in such work; on the one hand as an aspect of communication and cooperation at work and on the other hand...... as an aspect of human engagement with instruments of work. On the basis of previous work in activity-theoretical and semiotic human—computer interaction, we propose a model to encompass both of these aspects. In a dialogue with our empirical findings we move on to propose a number of types of mediation...... that have helped to enrich our understanding of mediated work and the design of computer mediation for such work....

  2. Agonist-induced internalisation of the glucagon-like peptide-1 receptor is mediated by the Gαq pathway.

    Science.gov (United States)

    Thompson, Aiysha; Kanamarlapudi, Venkateswarlu

    2015-01-01

    The glucagon-like peptide-1 receptor (GLP-1R) is a G-protein-coupled receptor (GPCR) and an important target in the treatment of type 2 diabetes mellitus (T2DM). Upon stimulation with agonist, the GLP-1R signals through both Gαs and Gαq coupled pathways to stimulate insulin secretion. The agonist-induced GLP-1R internalisation has recently been shown to be important for insulin secretion. However, the molecular mechanisms underlying GLP-1R internalisation remain unknown. The aim of this study was to determine the role of GLP-1R downstream signalling pathways in its internalisation. Agonist-induced human GLP-1R (hGLP-1R) internalisation and activity were examined using a number of techniques including immunoblotting, ELISA, immunofluorescence and luciferase assays to determine cAMP production, intracellular Ca(2+) accumulation and ERK phosphorylation. Agonist-induced hGLP-1R internalisation is dependent on caveolin-1 and dynamin. Inhibition of the Gαq pathway but not the Gαs pathway affected hGLP-1R internalisation. Consistent with this, hGLP-1R mutant T149M and small-molecule agonists (compound 2 and compound B), which activate only the Gαs pathway, failed to induce internalisation of the receptor. Chemical inhibitors of the Gαq pathway, PKC and ERK phosphorylation significantly reduced agonist-induced hGLP-1R internalisation. These inhibitors also suppressed agonist-induced ERK1/2 phosphorylation demonstrating that the phosphorylated ERK acts downstream of the Gαq pathway in the hGLP-1R internalisation. In summary, agonist-induced hGLP-1R internalisation is mediated by the Gαq pathway. The internalised hGLP-1R stimulates insulin secretion from pancreatic β-cells, indicating the importance of GLP-1 internalisation for insulin secretion. Copyright © 2014 Elsevier Inc. All rights reserved.

  3. Extracting the normal lung dose–response curve from clinical DVH data: a possible role for low dose hyper-radiosensitivity, increased radioresistance

    International Nuclear Information System (INIS)

    Gordon, J J; Snyder, K; Zhong, H; Barton, K; Sun, Z; Chetty, I J; Matuszak, M; Ten Haken, R K

    2015-01-01

    In conventionally fractionated radiation therapy for lung cancer, radiation pneumonitis’ (RP) dependence on the normal lung dose-volume histogram (DVH) is not well understood. Complication models alternatively make RP a function of a summary statistic, such as mean lung dose (MLD). This work searches over damage profiles, which quantify sub-volume damage as a function of dose. Profiles that achieve best RP predictive accuracy on a clinical dataset are hypothesized to approximate DVH dependence.Step function damage rate profiles R(D) are generated, having discrete steps at several dose points. A range of profiles is sampled by varying the step heights and dose point locations. Normal lung damage is the integral of R(D) with the cumulative DVH. Each profile is used in conjunction with a damage cutoff to predict grade 2 plus (G2+) RP for DVHs from a University of Michigan clinical trial dataset consisting of 89 CFRT patients, of which 17 were diagnosed with G2+ RP.Optimal profiles achieve a modest increase in predictive accuracy—erroneous RP predictions are reduced from 11 (using MLD) to 8. A novel result is that optimal profiles have a similar distinctive shape: enhanced damage contribution from low doses (<20 Gy), a flat contribution from doses in the range ∼20–40 Gy, then a further enhanced contribution from doses above 40 Gy. These features resemble the hyper-radiosensitivity / increased radioresistance (HRS/IRR) observed in some cell survival curves, which can be modeled using Joiner’s induced repair model.A novel search strategy is employed, which has the potential to estimate RP dependence on the normal lung DVH. When applied to a clinical dataset, identified profiles share a characteristic shape, which resembles HRS/IRR. This suggests that normal lung may have enhanced sensitivity to low doses, and that this sensitivity can affect RP risk. (paper)

  4. γ-Glutamylcysteine synthetase (γ-GCS) as a target for overcoming chemo- and radio-resistance of human hepatocellular carcinoma cells.

    Science.gov (United States)

    Lin, Li-Ching; Chen, Chi-Fen; Ho, Chun-Te; Liu, Jun-Jen; Liu, Tsan-Zon; Chern, Chi-Liang

    2018-04-01

    This study uncovered that the genetically endowed intracellular glutathione contents (iGSH) regulated by the catalytic subunit of γ‑glutamylcysteine synthetase heavy chain (γ‑GCSh) as a prime target for overcoming both the inherited and stimuli-activated chemo- and radio-resistance of hepatocellular carcinoma (HCC) cells. Reactive oxygen species (ROS) production and mitochondrial membrane potential (Δψm) were determined by the probe-based flow cytometry. The TUNEL assay was used as an index of radio-sensitivity and the MTT assay was used as an index of chemo-sensitivity against various anti-cancer agents. iGSH and γ‑GCSh activity were measured by HPLC methods. γ‑GCSh-overexpressing GCS30 cell line was established by tetracycline-controlled Tet-OFF gene expression system in SK-Hep-1 cells. The relative radio-sensitivities of a panel of five HCC cells were found to be correlated negatively with both the contents of iGSH and their corresponding γ‑GCSh activities with an order of abundance being Hep G2 > Hep 3B > J5 > Mahlavu > SK-Hep-1, respectively. Similarly, the cytotoxicity response patterns of these HCC cells against arsenic trioxide (ATO), a ROS-producing anti-cancer drug, were exactly identical to the order of ranking instigated by the radiotherapy (RT) treatment. Next, γ‑GCSh-overexpressing GCS30 cells were found to possess excellent ability to profoundly mitigate both the drop of Δψm and apoptotic TUNEL-positive cell population engendered by ATO, cisplatin, doxorubicin, and RT treatments. Our data unequivocally demonstrate that γ‑GCSh may represent a prime target for overcoming anti-cancer drugs and RT resistance for HCC cells. Copyright © 2018 Elsevier Inc. All rights reserved.

  5. Radioresistant Spodoptera frugiperda 9 insect cells display excessive resistance to 'endoplasmic reticulum' stress and calcium disturbances via pre-emptive activation of unfolded protein response pathway

    International Nuclear Information System (INIS)

    Guleria, Ayushi; Chandna, Sudhir

    2016-01-01

    Endoplasmic Reticulum (ER) performs multiple cellular functions such as proper folding of newly synthesized proteins and calcium homeostasis. ER stress triggers unfolded protein response (UPR) that attempts to restore normal ER function and resists damage-induced cell death. Lepidopteran Sf9 insect cells (derived from Spodoptera frugiperda) display 100-200 times higher radioresistance than mammalian cells. We have earlier reported that gamma-radiation doses <1000 Gy fail to trigger increase in cytosolic calcium in Sf9 cells, indicating resilience to calcium/ ER disturbances

  6. Single Strand Annealing Plays a Major Role in RecA-Independent Recombination between Repeated Sequences in the Radioresistant Deinococcus radiodurans Bacterium.

    Directory of Open Access Journals (Sweden)

    Solenne Ithurbide

    2015-10-01

    Full Text Available The bacterium Deinococcus radiodurans is one of the most radioresistant organisms known. It is able to reconstruct a functional genome from hundreds of radiation-induced chromosomal fragments. Our work aims to highlight the genes involved in recombination between 438 bp direct repeats separated by intervening sequences of various lengths ranging from 1,479 bp to 10,500 bp to restore a functional tetA gene in the presence or absence of radiation-induced DNA double strand breaks. The frequency of spontaneous deletion events between the chromosomal direct repeats were the same in recA+ and in ΔrecA, ΔrecF, and ΔrecO bacteria, whereas recombination between chromosomal and plasmid DNA was shown to be strictly dependent on the RecA and RecF proteins. The presence of mutations in one of the repeated sequence reduced, in a MutS-dependent manner, the frequency of the deletion events. The distance between the repeats did not influence the frequencies of deletion events in recA+ as well in ΔrecA bacteria. The absence of the UvrD protein stimulated the recombination between the direct repeats whereas the absence of the DdrB protein, previously shown to be involved in DNA double strand break repair through a single strand annealing (SSA pathway, strongly reduces the frequency of RecA- (and RecO- independent deletions events. The absence of the DdrB protein also increased the lethal sectoring of cells devoid of RecA or RecO protein. γ-irradiation of recA+ cells increased about 10-fold the frequencies of the deletion events, but at a lesser extend in cells devoid of the DdrB protein. Altogether, our results suggest a major role of single strand annealing in DNA repeat deletion events in bacteria devoid of the RecA protein, and also in recA+ bacteria exposed to ionizing radiation.

  7. ATM-mediated Snail Serine 100 phosphorylation regulates cellular radiosensitivity

    International Nuclear Information System (INIS)

    Boohaker, Rebecca J.; Cui, Xiaoli; Stackhouse, Murray; Xu, Bo

    2013-01-01

    Purpose: Activation of the DNA damage responsive protein kinase ATM is a critical step for cellular survival in response to ionizing irradiation (IR). Direct targets of ATM regulating radiosensitivity remain to be fully investigated. We have recently reported that ATM phosphorylates the transcriptional repressor Snail on Serine 100. We aimed to further study the functional significance of ATM-mediated Snail phosphorylation in response to IR. Material and methods: We transfected vector-only, wild-type, the Serine 100 to alanine (S100A) or to glutamic acid (S100E) substitution of Snail into various cell lines. We assessed colony formation, γ-H2AX focus formation and the invasion index in the cells treated with or without IR. Results: We found that over-expression of the S100A mutant Snail in HeLa cells significantly increased radiosensitivity. Meanwhile the expression of S100E, a phospho-mimicking mutation, resulted in enhanced radio-resistance. Interestingly, S100E could rescue the radiosensitive phenotype in ATM-deficient cells. We also found that expression of S100E increased γ-H2AX focus formation and compromised inhibition of invasion in response to IR independent of cell survival. Conclusion: ATM-mediated Snail Serine 100 phosphorylation in response to IR plays an important part in the regulation of radiosensitivity

  8. Mediatized play

    DEFF Research Database (Denmark)

    Johansen, Stine Liv

    Children’s play must nowadays be understood as a mediatized field in society and culture. Media – understood in a very broad sense - holds severe explanatory power in describing and understanding the practice of play, since play happens both with, through and inspired by media of different sorts........ In this presentation the case of ‘playing soccer’ will be outlined through its different mediated manifestations, including soccer games and programs on TV, computer games, magazines, books, YouTube videos and soccer trading cards....

  9. Mediating Business

    DEFF Research Database (Denmark)

    "Mediating Business" is a study of the expansion of business journalism. Building on evidence from Denmark, Finland, Norway and Sweden, "Mediating Business" is a comparative and multidisciplinary study of one of the major transformations of the mass media and the realm of business - nationally...... and globally. The book explores the history of key innovations and innovators in the business press. It analyzes changes in the discourse of business journalism associated with the growth in business news and the development of new ways of framing business issues and events. Finally, it examines...... the organizational implications of the increased media visibility of business and, in particular, the development of corporate governance and media relations....

  10. Effects of chronic whole-body gamma irradiation on cell mediated immunity

    International Nuclear Information System (INIS)

    Shifrine, M.; Taylor, N.J.; Wilson, F.D.; DeRock, E.W.; Wiger, N.

    1979-01-01

    The whole blood lymphocyte stimulation test has been used to estimate the effects of chronic, whole-body, gamma irradiation in the dog. At lower dose levels, 0.07 and 0.33 R/day to cumulative dose of about 50 and 250 R, there was no change in cell mediated immunity. Dogs at high dose levels were affected. Dogs which succumbed to aplastic anemia at high doses had reduced immunological responses. Dogs which survived these high doses showed a temporary depression. When aplastic anemia was initially noted, there was a differential response to PHA and Con-A stimulation. The response to the former mitogen was profoundly reduced, but Con-A stimulated cells were unaffected, indicative of the development of radioresistant cell lines. As the dogs progressed toward aplastic anemia, all T lympocytes were negatively affected

  11. Cell death induced by ionizing radiations in human radio-resistant tumours: in-vitro and in-vivo study of mechanisms involved in its induction by different types of radiations and pharmacological modulation

    International Nuclear Information System (INIS)

    Altmeyer, Anais

    2010-01-01

    Whereas chemo-radiotherapy protocols revealed to be very efficient when taking tumours into care, the treatment of some tumours remains very limited due to their critical location or to the weak radio-sensitivity to conventional radiations. One way to work around this problem is to use high linear energy transfer radiations or hadron therapy, in combination with radio-sensitizers. This research thesis reports the assessment of radio-sensitizer effects of different molecules on human radio-resistant cell lines and more particularly the SK-Hep1 line from a hepatocellular carcinoma. In vitro studies have been performed and then in vivo studies by using fast neutron irradiation on a mice liver sample. Observations made by optic fibre confocal microscopy and transmission electronic microscopy confirmed in vitro observations: the prevailing cell death after such an irradiation is the autophagic cell death. It shows the importance of the autophagic phenomenon induced by radiations with high linear transfer energy. This could lead to new therapeutic protocols for radio-resistant cancers [fr

  12. Signal transduction in neurons: effects of cellular prion protein on fyn kinase and ERK1/2 kinase

    Directory of Open Access Journals (Sweden)

    Tomasi Vittorio

    2010-12-01

    Full Text Available Abstract Background It has been reported that cellular prion protein (PrPc co-localizes with caveolin-1 and participates to signal transduction events by recruiting Fyn kinase. As PrPc is a secreted protein anchored to the outer surface membrane through a glycosylphosphatidylinositol (GPI anchor (secPrP and caveolin-1 is located in the inner leaflet of plasma membrane, there is a problem of how the two proteins can physically interact each other and transduce signals. Results By using the GST-fusion proteins system we observed that PrPc strongly interacts with caveolin-1 scaffolding domain and with a caveolin-1 hydrophilic C-terminal region, but not with the caveolin-1 N-terminal region. In vitro binding experiments were also performed to define the site(s of PrPc interacting with cav-1. The results are consistent with a participation of PrPc octapeptide repeats motif in the binding to caveolin-1 scaffolding domain. The caveolar localization of PrPc was ascertained by co-immunoprecipitation, by co-localization after flotation in density gradients and by confocal microscopy analysis of PrPc and caveolin-1 distributions in a neuronal cell line (GN11 expressing caveolin-1 at high levels. Conclusions We observed that, after antibody-mediated cross-linking or copper treatment, PrPc was internalized probably into caveolae. We propose that following translocation from rafts to caveolae or caveolae-like domains, secPrP could interact with caveolin-1 and induce signal transduction events.

  13. Signal transduction in neurons: effects of cellular prion protein on fyn kinase and ERK1/2 kinase.

    Science.gov (United States)

    Tomasi, Vittorio

    2010-12-16

    It has been reported that cellular prion protein (PrPc) co-localizes with caveolin-1 and participates to signal transduction events by recruiting Fyn kinase. As PrPc is a secreted protein anchored to the outer surface membrane through a glycosylphosphatidylinositol (GPI) anchor (secPrP) and caveolin-1 is located in the inner leaflet of plasma membrane, there is a problem of how the two proteins can physically interact each other and transduce signals. By using the GST-fusion proteins system we observed that PrPc strongly interacts with caveolin-1 scaffolding domain and with a caveolin-1 hydrophilic C-terminal region, but not with the caveolin-1 N-terminal region. In vitro binding experiments were also performed to define the site(s) of PrPc interacting with cav-1. The results are consistent with a participation of PrPc octapeptide repeats motif in the binding to caveolin-1 scaffolding domain. The caveolar localization of PrPc was ascertained by co-immunoprecipitation, by co-localization after flotation in density gradients and by confocal microscopy analysis of PrPc and caveolin-1 distributions in a neuronal cell line (GN11) expressing caveolin-1 at high levels. We observed that, after antibody-mediated cross-linking or copper treatment, PrPc was internalized probably into caveolae. We propose that following translocation from rafts to caveolae or caveolae-like domains, secPrP could interact with caveolin-1 and induce signal transduction events.

  14. Study of radioresistance of microorganisms

    International Nuclear Information System (INIS)

    Olbrichova, D.

    1983-01-01

    Strain radiosensitivity was evaluated on the basis of the determination of inactivation curve parameters and the determination of the D 10 value. The course of curves was investigated for two 60 Co sources, RCHM-gamma-20 (USSR) with an activity of 2.54x10 14 Bq and AECL (type J-6000, Canada) with an activity of 4.92x10 16 Bq. The curve parameters were determined for microorganisms in buffer medium and for cultures in dehydrated condition. Coccus germs were irradiated with doses of 1, 2, 3, 4, 5 and 6 kGy and aerobic sporulates with doses of 3, 6, 9, 12 and 15 kGy. For comparing the resistance of isolated strains the t-test was used. The most resistant of the isolated strains were Bacillus cereus, Bacillus subtilis, Bacillus pumilus and Bacillus megatherium. (E.S.)

  15. RAD18 mediates resistance to ionizing radiation in human glioma cells

    International Nuclear Information System (INIS)

    Xie, Chen; Wang, Hongwei; Cheng, Hongbin; Li, Jianhua; Wang, Zhi; Yue, Wu

    2014-01-01

    Highlights: • RAD18 is an important mediator of the IR-induced resistance in glioma cell lines. • RAD18 overexpression confers resistance to IR-mediated apoptosis. • The elevated expression of RAD18 is associated with recurrent GBM who underwent IR therapy. - Abstract: Radioresistance remains a major challenge in the treatment of glioblastoma multiforme (GBM). RAD18 a central regulator of translesion DNA synthesis (TLS), has been shown to play an important role in regulating genomic stability and DNA damage response. In the present study, we investigate the relationship between RAD18 and resistance to ionizing radiation (IR) and examined the expression levels of RAD18 in primary and recurrent GBM specimens. Our results showed that RAD18 is an important mediator of the IR-induced resistance in GBM. The expression level of RAD18 in glioma cells correlates with their resistance to IR. Ectopic expression of RAD18 in RAD18-low A172 glioma cells confers significant resistance to IR treatment. Conversely, depletion of endogenous RAD18 in RAD18-high glioma cells sensitized these cells to IR treatment. Moreover, RAD18 overexpression confers resistance to IR-mediated apoptosis in RAD18-low A172 glioma cells, whereas cells deficient in RAD18 exhibit increased apoptosis induced by IR. Furthermore, knockdown of RAD18 in RAD18-high glioma cells disrupts HR-mediated repair, resulting in increased accumulation of DSB. In addition, clinical data indicated that RAD18 was significantly higher in recurrent GBM samples that were exposed to IR compared with the corresponding primary GBM samples. Collectively, our findings reveal that RAD18 may serve as a key mediator of the IR response and may function as a potential target for circumventing IR resistance in human GBM

  16. mediation: R package for causal mediation analysis

    OpenAIRE

    Tingley, Dustin; Yamamoto, Teppei; Hirose, Kentaro; Keele, Luke; Imai, Kosuke

    2012-01-01

    In this paper, we describe the R package mediation for conducting causal mediation analysis in applied empirical research. In many scientific disciplines, the goal of researchers is not only estimating causal effects of a treatment but also understanding the process in which the treatment causally affects the outcome. Causal mediation analysis is frequently used to assess potential causal mechanisms. The mediation package implements a comprehensive suite of statistical tools for conducting su...

  17. Micro dynamics in mediation

    OpenAIRE

    Boserup, Hans

    2014-01-01

    The author has identified a number of styles in mediation, which lead to different processes and different outcomes. Through discourse and conversation analysis he examines the micro dynamics in three of these, the postmodern styles: systemic, transformative and narrative mediation. The differences between the three mediation ideologies and practice is illustrated through role play scripts enacted in each style. Mediator and providers of mediation and trainers in mediation are encouraged to a...

  18. Radioresistance of chordoma cells is associated with the ATM/ATR pathway, in which RAD51 serves as an important downstream effector.

    Science.gov (United States)

    Zhang, Chao; Wang, Bing; Li, Lei; Li, Yawei; Li, Pengzhi; Lv, Guohua

    2017-09-01

    Surgery followed by radiotherapy is the standard treatment for chordomas, which are a rare but low-grade type of bone cancer arising from remnants of the embryonic notochord. However, disease recurrence following radiotherapy is common, most likely due to endogenous DNA repair mechanisms that promote cell survival upon radiation strikes. The ataxia telangiectasia mutated/ataxia telangiectasia mutated and Rad3 related (ATM/ATR)-mediated pathway has a critical role in DNA repair mechanisms; however, it has rarely been investigated in chordomas. In the present study, the expression of signal molecules related to the ATM/ATR pathway in chordoma tissues and adjacent normal tissues were initially examined using immunohistochemistry and western blot analysis. Chordoma U-CH1 and U-CH2 cells were subsequently used to investigate cell responses to ionizing radiation and the potential protective actions mediated by the ATM/ATR pathway. Phosphorylated (p)-ATM, p-ATR, γ-H2A histone family, member X (H2AX) and RAD51 were significantly upregulated in chordoma tissues relative to adjacent normal tissues (PATM, γ-H2AX and RAD51 expression in U-CH1 cells (PATM, p-ATR and RAD51 levels in U-CH2 cells (PATM/ATR pathway, in which RAD51 serves as an important downstream effector. Thus, RAD51 presents a promising therapeutic target for improving the outcome of radiotherapy treatment in chordomas.

  19. Internalization of titanium dioxide nanoparticles by glial cells is given at short times and is mainly mediated by actin reorganization-dependent endocytosis.

    Science.gov (United States)

    Huerta-García, Elizabeth; Márquez-Ramírez, Sandra Gissela; Ramos-Godinez, María Del Pilar; López-Saavedra, Alejandro; Herrera, Luis Alonso; Parra, Alberto; Alfaro-Moreno, Ernesto; Gómez, Erika Olivia; López-Marure, Rebeca

    2015-12-01

    Many nanoparticles (NPs) have toxic effects on multiple cell lines. This toxicity is assumed to be related to their accumulation within cells. However, the process of internalization of NPs has not yet been fully characterized. In this study, the cellular uptake, accumulation, and localization of titanium dioxide nanoparticles (TiO2 NPs) in rat (C6) and human (U373) glial cells were analyzed using time-lapse microscopy (TLM) and transmission electron microscopy (TEM). Cytochalasin D (Cyt-D) was used to evaluate whether the internalization process depends of actin reorganization. To determine whether the NP uptake is mediated by phagocytosis or macropinocytosis, nitroblue tetrazolium (NBT) reduction was measured and the 5-(N-ethyl-N-isopropyl)-amiloride was used. Expression of proteins involved with endocytosis and exocytosis such as caveolin-1 (Cav-1) and cysteine string proteins (CSPs) was also determined using flow cytometry. TiO2 NPs were taken up by both cell types, were bound to cellular membranes and were internalized at very short times after exposure (C6, 30 min; U373, 2h). During the uptake process, the formation of pseudopodia and intracellular vesicles was observed, indicating that this process was mediated by endocytosis. No specific localization of TiO2 NPs into particular organelles was found: in contrast, they were primarily localized into large vesicles in the cytoplasm. Internalization of TiO2 NPs was strongly inhibited by Cyt-D in both cells and by amiloride in U373 cells; besides, the observed endocytosis was not associated with NBT reduction in either cell type, indicating that macropinocytosis is the main process of internalization in U373 cells. In addition, increases in the expression of Cav-1 protein and CSPs were observed. In conclusion, glial cells are able to internalize TiO2 NPs by a constitutive endocytic mechanism which may be associated with their strong cytotoxic effect in these cells; therefore, TiO2 NPs internalization and their

  20. Double-negative feedback loop between long non-coding RNA TUG1 and miR-145 promotes epithelial to mesenchymal transition and radioresistance in human bladder cancer cells.

    Science.gov (United States)

    Tan, Jiemei; Qiu, Kaifeng; Li, Mingyi; Liang, Ying

    2015-10-07

    LncRNAs have a critical role in the regulation of cellular processes such as cancer progression and metastasis. In the present study, we confirmed that TUG1 was overexpressed in bladder cancer tissues and established cell lines. Knockdown of TUG1 inhibited bladder cancer cell metastasis both in vitro and in vivo. Furthermore, we found that TUG1 promoted cancer cell invasion and radioresistance through inducing epithelial-to-mesenchymal transition (EMT). Interestingly, TUG1 decreased the expression of miR-145 and there was a reciprocal repression between TUG1 and miR-145 in an Argonaute2-dependent manner. ZEB2 was identified as a down-stream target of miR-145 and TUG1 exerted its function through the miR-145/ZEB2 axis. In summary, our data indicated that blocking TUG1 function may be an effective anti-cancer therapy. Copyright © 2015 Federation of European Biochemical Societies. Published by Elsevier B.V. All rights reserved.

  1. MiR-146b-5p overexpression attenuates stemness and radioresistance of glioma stem cells by targeting HuR/lincRNA-p21/β-catenin pathway

    Science.gov (United States)

    Yang, Wei; Yu, Hongquan; Shen, Yueming; Liu, Yingying; Yang, Zhanshan; Sun, Ting

    2016-01-01

    A stem-like subpopulation existed in GBM cells, called glioma stem cells (GSCs), might contribute to cancer invasion, angiogenesis, immune evasion, and therapeutic resistance, providing a rationale to eliminate GSCs population and their supporting niche for successful GBM treatment. LincRNA-p21, a novel regulator of cell proliferation, apoptosis and DNA damage response, is found to be downregulated in several types of tumor. However, little is known about the role of lincRNA-p21 in stemness and radioresistance of GSCs and its regulating mechanisms. In this study, we found that lincRNA-p21 negatively regulated the expression and activity of β-catenin in GSCs. Downregulation of lincRNA-p21 in GSCs was resulted from upregulation of Hu antigen R (HuR) expression caused by miR-146b-5p downregulation. MiR-146b-5p overexpression increased apoptosis and radiosensitivity, decreased cell viability, neurosphere formation capacity and stem cell marker expression, and induced differentiation in GSCs. Moreover, knock-down lincRNA-p21 or HuR and β-catenin overexpression could rescue the phenotypic changes resulted from miR-146b-5p overexpression in GSCs. These findings suggest that targeting the miR-146b-5p/HuR/lincRNA-p21/β-catenin signaling pathway may be valuable therapeutic strategies against glioma. PMID:27166258

  2. Bcl-w, a Radio-resistant Protein, Promotes the Gastric Cancer Cell Migration by inducing the phosphorylation of Focal Adhesion Kinase

    International Nuclear Information System (INIS)

    Bae, In Hwa; Yoon, Sung Hwan; Um, Hong Duck

    2008-01-01

    Gastric cancer is one of the leading malignancies in many countries and lethal for the high incidence of recurrence even after drastic surgical resection. Because local invasion and subsequent metastasis contributes to the failure of anticancer treatments of gastric cancer, a better understanding of the mechanisms involved in tumor invasiveness within the stomach seems to be essential for the control of this disease. Bcl-w is a prosurvival member of the Bcl-2 protein family, and thus protects cells from γ-irradiation. Recent reports suggest that Bcl-w can be upregulated in gastric cancer cells in a manner associated with the infiltrative (diffuse) types of the tumor. An analysis of Bcl-w function consistently revealed that Bcl-w can also promote the migratory and invasive potentials of gastric cancer cells. While it was shown that Bcl-w increases the invasiveness of cancer cells by sequentially inducing PI3K, Akt, SP1, and MMP-2, cellular components involved in Bcl-w-induced cell migration remain to be determined. This was the reason why we undertook the present study, which shows that FAK is a critical mediator of the cell migration induced by Bcl-w

  3. Nordic Mediation Reseach

    DEFF Research Database (Denmark)

    A presentation of 12 studies on mediation from researchers from Denmark, Finland, Norway and Sweden.......A presentation of 12 studies on mediation from researchers from Denmark, Finland, Norway and Sweden....

  4. Bayesian Mediation Analysis

    OpenAIRE

    Yuan, Ying; MacKinnon, David P.

    2009-01-01

    This article proposes Bayesian analysis of mediation effects. Compared to conventional frequentist mediation analysis, the Bayesian approach has several advantages. First, it allows researchers to incorporate prior information into the mediation analysis, thus potentially improving the efficiency of estimates. Second, under the Bayesian mediation analysis, inference is straightforward and exact, which makes it appealing for studies with small samples. Third, the Bayesian approach is conceptua...

  5. mediation: R Package for Causal Mediation Analysis

    Directory of Open Access Journals (Sweden)

    Dustin Tingley

    2014-09-01

    Full Text Available In this paper, we describe the R package mediation for conducting causal mediation analysis in applied empirical research. In many scientific disciplines, the goal of researchers is not only estimating causal effects of a treatment but also understanding the process in which the treatment causally affects the outcome. Causal mediation analysis is frequently used to assess potential causal mechanisms. The mediation package implements a comprehensive suite of statistical tools for conducting such an analysis. The package is organized into two distinct approaches. Using the model-based approach, researchers can estimate causal mediation effects and conduct sensitivity analysis under the standard research design. Furthermore, the design-based approach provides several analysis tools that are applicable under different experimental designs. This approach requires weaker assumptions than the model-based approach. We also implement a statistical method for dealing with multiple (causally dependent mediators, which are often encountered in practice. Finally, the package also offers a methodology for assessing causal mediation in the presence of treatment noncompliance, a common problem in randomized trials.

  6. Bayesian Mediation Analysis

    Science.gov (United States)

    Yuan, Ying; MacKinnon, David P.

    2009-01-01

    In this article, we propose Bayesian analysis of mediation effects. Compared with conventional frequentist mediation analysis, the Bayesian approach has several advantages. First, it allows researchers to incorporate prior information into the mediation analysis, thus potentially improving the efficiency of estimates. Second, under the Bayesian…

  7. General gauge mediation

    International Nuclear Information System (INIS)

    Meade, Patrick; Seiberg, Nathan; Shih, David

    2009-01-01

    We give a general definition of gauge mediated supersymmetry breaking which encompasses all the known gauge mediation models. In particular, it includes both models with messengers as well as direct mediation models. A formalism for computing the soft terms in the generic model is presented. Such a formalism is necessary in strongly-coupled direct mediation models where perturbation theory cannot be used. It allows us to identify features of the entire class of gauge mediation models and to distinguish them from specific signatures of various subclasses. (author)

  8. Bayesian dynamic mediation analysis.

    Science.gov (United States)

    Huang, Jing; Yuan, Ying

    2017-12-01

    Most existing methods for mediation analysis assume that mediation is a stationary, time-invariant process, which overlooks the inherently dynamic nature of many human psychological processes and behavioral activities. In this article, we consider mediation as a dynamic process that continuously changes over time. We propose Bayesian multilevel time-varying coefficient models to describe and estimate such dynamic mediation effects. By taking the nonparametric penalized spline approach, the proposed method is flexible and able to accommodate any shape of the relationship between time and mediation effects. Simulation studies show that the proposed method works well and faithfully reflects the true nature of the mediation process. By modeling mediation effect nonparametrically as a continuous function of time, our method provides a valuable tool to help researchers obtain a more complete understanding of the dynamic nature of the mediation process underlying psychological and behavioral phenomena. We also briefly discuss an alternative approach of using dynamic autoregressive mediation model to estimate the dynamic mediation effect. The computer code is provided to implement the proposed Bayesian dynamic mediation analysis. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

  9. Causal mediation analysis with multiple mediators.

    Science.gov (United States)

    Daniel, R M; De Stavola, B L; Cousens, S N; Vansteelandt, S

    2015-03-01

    In diverse fields of empirical research-including many in the biological sciences-attempts are made to decompose the effect of an exposure on an outcome into its effects via a number of different pathways. For example, we may wish to separate the effect of heavy alcohol consumption on systolic blood pressure (SBP) into effects via body mass index (BMI), via gamma-glutamyl transpeptidase (GGT), and via other pathways. Much progress has been made, mainly due to contributions from the field of causal inference, in understanding the precise nature of statistical estimands that capture such intuitive effects, the assumptions under which they can be identified, and statistical methods for doing so. These contributions have focused almost entirely on settings with a single mediator, or a set of mediators considered en bloc; in many applications, however, researchers attempt a much more ambitious decomposition into numerous path-specific effects through many mediators. In this article, we give counterfactual definitions of such path-specific estimands in settings with multiple mediators, when earlier mediators may affect later ones, showing that there are many ways in which decomposition can be done. We discuss the strong assumptions under which the effects are identified, suggesting a sensitivity analysis approach when a particular subset of the assumptions cannot be justified. These ideas are illustrated using data on alcohol consumption, SBP, BMI, and GGT from the Izhevsk Family Study. We aim to bridge the gap from "single mediator theory" to "multiple mediator practice," highlighting the ambitious nature of this endeavor and giving practical suggestions on how to proceed. © 2014 The Authors Biometrics published by Wiley Periodicals, Inc. on behalf of International Biometric Society.

  10. Flexible Mediation Analysis With Multiple Mediators.

    Science.gov (United States)

    Steen, Johan; Loeys, Tom; Moerkerke, Beatrijs; Vansteelandt, Stijn

    2017-07-15

    The advent of counterfactual-based mediation analysis has triggered enormous progress on how, and under what assumptions, one may disentangle path-specific effects upon combining arbitrary (possibly nonlinear) models for mediator and outcome. However, current developments have largely focused on single mediators because required identification assumptions prohibit simple extensions to settings with multiple mediators that may depend on one another. In this article, we propose a procedure for obtaining fine-grained decompositions that may still be recovered from observed data in such complex settings. We first show that existing analytical approaches target specific instances of a more general set of decompositions and may therefore fail to provide a comprehensive assessment of the processes that underpin cause-effect relationships between exposure and outcome. We then outline conditions for obtaining the remaining set of decompositions. Because the number of targeted decompositions increases rapidly with the number of mediators, we introduce natural effects models along with estimation methods that allow for flexible and parsimonious modeling. Our procedure can easily be implemented using off-the-shelf software and is illustrated using a reanalysis of the World Health Organization's Large Analysis and Review of European Housing and Health Status (WHO-LARES) study on the effect of mold exposure on mental health (2002-2003). © The Author(s) 2017. Published by Oxford University Press on behalf of the Johns Hopkins Bloomberg School of Public Health. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  11. Technology-Use Mediation

    DEFF Research Database (Denmark)

    Bansler, Jørgen P.; Havn, Erling C.

    2003-01-01

    This study analyzes how a group of ‘mediators’ in a large, multinational company adapted a computer-mediated communication technology (a ‘virtual workspace’) to the organizational context (and vice versa) by modifying features of the technology, providing ongoing support for users, and promoting...... appropriate conventions of use. Our findings corroborate earlier research on technology-use mediation, which suggests that such mediators can exert considerable influence on how a particular technology will be established and used in an organization. However, this study also indicates that the process...... of technology-use mediation is more complex and indeterminate than earlier literature suggests. In particular, we want to draw attention to the fact that advanced computer-mediated communication technologies are equivocal and that technology-use mediation consequently requires ongoing sensemaking (Weick 1995)....

  12. The Schizosaccharomyces pombe Mediator

    DEFF Research Database (Denmark)

    Venturi, Michela

    , Schizosaccharomyces pombe and mammalian Mediator. In our study, we have taken the S. pombe Mediator into consideration and characterized genetically and biochemically two subunits already know in S. cerevisiae, Med9 and Med11, but still not identified in the S. pombe Mediator. Genetic analysis has shown that med9......In the past several years great attention has been dedicated to the characterization of the Mediator complex in a different range of model organisms. Mediator is a conserved co-activator complex involved in transcriptional regulation and it conveys signals from regulatory transcription factors...... to the basal transcription machinery. Mediator was initially isolated from Saccharomyces cerevisiae based on its ability to render a RNA polymerase II in vitro transcription system responsive to activators. Additionally, structural studies have revealed striking structural similarities between S. cerevisiae...

  13. Applied mediation analyses

    DEFF Research Database (Denmark)

    Lange, Theis; Hansen, Kim Wadt; Sørensen, Rikke

    2017-01-01

    In recent years, mediation analysis has emerged as a powerful tool to disentangle causal pathways from an exposure/treatment to clinically relevant outcomes. Mediation analysis has been applied in scientific fields as diverse as labour market relations and randomized clinical trials of heart...... disease treatments. In parallel to these applications, the underlying mathematical theory and computer tools have been refined. This combined review and tutorial will introduce the reader to modern mediation analysis including: the mathematical framework; required assumptions; and software implementation...

  14. Immunologically mediated oral diseases

    OpenAIRE

    Jimson, Sudha; Balachader, N.; Anita, N.; Babu, R.

    2015-01-01

    Immune mediated diseases of oral cavity are uncommon. The lesions may be self-limiting and undergo remission spontaneously. Among the immune mediated oral lesions the most important are lichen planus, pemphigus, erythema multiformi, epidermolysis bullosa, systemic lupus erythematosis. Cellular and humoral mediated immunity play a major role directed against epithelial and connective tissue in chronic and recurrent patterns. Confirmatory diagnosis can be made by biopsy, direct and indirect imm...

  15. Implementing general gauge mediation

    International Nuclear Information System (INIS)

    Carpenter, Linda M.; Dine, Michael; Festuccia, Guido; Mason, John D.

    2009-01-01

    Recently there has been much progress in building models of gauge mediation, often with predictions different than those of minimal gauge mediation. Meade, Seiberg, and Shih have characterized the most general spectrum which can arise in gauge-mediated models. We discuss some of the challenges of building models of general gauge mediation, especially the problem of messenger parity and issues connected with R symmetry breaking and CP violation. We build a variety of viable, weakly coupled models which exhibit some or all of the possible low energy parameters.

  16. Teaching Mediated Public Relations.

    Science.gov (United States)

    Kent, Michael L.

    2001-01-01

    Discusses approaches to teaching a mediated public relations course, emphasizing the World Wide Web. Outlines five course objectives, assignments and activities, evaluation, texts, and lecture topics. Argues that students mastering these course objectives will understand ethical issues relating to media use, using mediated technology in public…

  17. Fashion, Mediations & Method Assemblages

    DEFF Research Database (Denmark)

    Sommerlund, Julie; Jespersen, Astrid Pernille

    of handling multiple, fluid realities with multiple, fluid methods. Empirically, the paper works with mediation in fashion - that is efforts the active shaping of relations between producer and consumer through communication, marketing and PR. Fashion mediation is by no means simple, but organise complex...

  18. The Mediated Transparent Society

    DEFF Research Database (Denmark)

    Backer, Lise

    2001-01-01

    in the mediated transparent society. The paper concludes that, based on these analyses, the mediated panopticism working on the business segment is not an effective disciplinary apparatus, which can guarantee that business corporations are carrying out important ecological or ethical improvements....

  19. Laccase/Mediator Systems

    NARCIS (Netherlands)

    Hilgers, Roelant; Vincken, Jean Paul; Gruppen, Harry; Kabel, Mirjam A.

    2018-01-01

    Laccase-mediator systems (LMS) have been widely studied for their capacity to oxidize the nonphenolic subunits of lignin (70-90% of the polymer). The phenolic subunits (10-30% of the polymer), which can also be oxidized without mediators, have received considerably less attention. Consequently, it

  20. The multitalented Mediator complex.

    Science.gov (United States)

    Carlsten, Jonas O P; Zhu, Xuefeng; Gustafsson, Claes M

    2013-11-01

    The Mediator complex is needed for regulated transcription of RNA polymerase II (Pol II)-dependent genes. Initially, Mediator was only seen as a protein bridge that conveyed regulatory information from enhancers to the promoter. Later studies have added many other functions to the Mediator repertoire. Indeed, recent findings show that Mediator influences nearly all stages of transcription and coordinates these events with concomitant changes in chromatin organization. We review the multitude of activities associated with Mediator and discuss how this complex coordinates transcription with other cellular events. We also discuss the inherent difficulties associated with in vivo characterization of a coactivator complex that can indirectly affect diverse cellular processes via changes in gene transcription. Copyright © 2013 Elsevier Ltd. All rights reserved.

  1. Music, radio and mediatization

    DEFF Research Database (Denmark)

    Michelsen, Morten; Krogh, Mads

    2016-01-01

    of mediatization where media as such seem to be ascribed agency. Instead, we consider historical accounts of music–radio in order to address the complex nonlinearity of concrete processes of mediatization as they take place in the multiple meetings between a decentred notion of radio and musical life.......Mediatization has become a key concept for understanding the relations between media and other cultural and social fields. Contributing to the discussions related to the concept of mediatization, this article discusses how practices of radio and music(al life) influence each other. We follow Deacon......’s and Stanyer’s advice to supplement the concept of mediatization with ‘a series of additional concepts at lower levels of abstraction’ and suggest, in this respect, the notion of heterogeneous milieus of music–radio. Hereby, we turn away from the all-encompassing perspectives related to the concept...

  2. Role of Caveolin 1, E-Cadherin, Enolase 2 and PKCalpha on resistance to methotrexate in human HT29 colon cancer cells

    DEFF Research Database (Denmark)

    Selga, Elisabet; Morales Torres, Christina; Noé, Véronique

    2008-01-01

    , a list of 3-fold differentially expressed genes with a p-value multiple testing correction (Benjamini and Hochberg false discovery rate) was generated. RT-Real-time PCR was used to validate the expression levels of selected genes and copy-number was determined by qPCR. Functional......ABSTRACT: BACKGROUND: Methotrexate is one of the earliest cytotoxic drugs used in cancer therapy, and despite the isolation of multiple other folate antagonists, methotrexate maintains its significant role as a treatment for different types of cancer and other disorders. The usefulness of treatment...

  3. Caveolin1 Is Required for Th1 Cell Infiltration, but Not Tight Junction Remodeling, at the Blood-Brain Barrier in Autoimmune Neuroinflammation

    Directory of Open Access Journals (Sweden)

    Sarah E. Lutz

    2017-11-01

    Full Text Available Lymphocytes cross vascular boundaries via either disrupted tight junctions (TJs or caveolae to induce tissue inflammation. In the CNS, Th17 lymphocytes cross the blood-brain barrier (BBB before Th1 cells; yet this differential crossing is poorly understood. We have used intravital two-photon imaging of the spinal cord in wild-type and caveolae-deficient mice with fluorescently labeled endothelial tight junctions to determine how tight junction remodeling and caveolae regulate CNS entry of lymphocytes during the experimental autoimmune encephalomyelitis (EAE model for multiple sclerosis. We find that dynamic tight junction remodeling occurs early in EAE but does not depend upon caveolar transport. Moreover, Th1, but not Th17, lymphocytes are significantly reduced in the inflamed CNS of mice lacking caveolae. Therefore, tight junction remodeling facilitates Th17 migration across the BBB, whereas caveolae promote Th1 entry into the CNS. Moreover, therapies that target both tight junction degradation and caveolar transcytosis may limit lymphocyte infiltration during inflammation.

  4. Study of multidrug resistance and radioresistance

    International Nuclear Information System (INIS)

    Kang, Yoon Koo; Yoo, Young Do

    1999-04-01

    We investigated the mechanism of 5-FU, adriamycin, radiation resistance in Korean gastric cancer cells. First we investigated the relation between Rb and multidrug resistance. Rb stable transfectants exhibited 5- to 10- fold more resistance to adriamycin than the control cells. These Rb transfectants showed increased MDR1 expression. We also investigated up-regulation in radiation-resistant tumor tissues. HSP27, MRP-8, GST, and NKEF-B were up-regulated in radiation resistant tumor. Expression of NKEF-B was also increased by radiation exposure in Head and Neck cells. These results demonstrated that NKEF-B is a stress response protein and it may have an important role in radiation resistance

  5. Induction of transient radioresistance in human erythrocytes

    International Nuclear Information System (INIS)

    Krokosz, Anita; Szweda-Lewandowska, Zofia

    2006-01-01

    Human erythrocytes suspended in an isotonic Na-phosphate buffer, pH 7.4 (hematocrit of 2%), were irradiated with γ-rays with single and split doses under air or N 2 O in order to determine the physicochemical changes caused by the dose inducing an increase in resistance to radiation-induced hemolysis. The obtained results showed that under the applied irradiation conditions, the dose of 0.4 kGy induced changes in erythrocytes, which were responsible for temporary resistance of erythrocytes to hemolysis. We concluded that the observed resistance is caused mainly by the structural changes in proteins

  6. General resonance mediation

    International Nuclear Information System (INIS)

    McGarrie, Moritz

    2012-07-01

    We extend the framework of general gauge mediation to cases where the mediating fields have a nontrivial spectral function, as might arise from strong dynamics. We demonstrate through examples that this setup describes a broad class of possible models of gauge mediated supersymmetry breaking. A main emphasis is to give general formulas for cross sections for σ(visible → hidden) in these resonance models. We will also give formulas for soft masses, A-terms and demonstrate the framework with a holographic setup.

  7. General resonance mediation

    Energy Technology Data Exchange (ETDEWEB)

    McGarrie, Moritz

    2012-07-15

    We extend the framework of general gauge mediation to cases where the mediating fields have a nontrivial spectral function, as might arise from strong dynamics. We demonstrate through examples that this setup describes a broad class of possible models of gauge mediated supersymmetry breaking. A main emphasis is to give general formulas for cross sections for {sigma}(visible {yields} hidden) in these resonance models. We will also give formulas for soft masses, A-terms and demonstrate the framework with a holographic setup.

  8. Positively deflected anomaly mediation

    International Nuclear Information System (INIS)

    Okada, Nobuchika

    2002-01-01

    We generalize the so-called 'deflected anomaly mediation' scenario to the case where threshold corrections of heavy messengers to the sparticle squared masses are positive. A concrete model realizing this scenario is also presented. The tachyonic slepton problem can be fixed with only a pair of messengers. The resultant sparticle mass spectrum is quite different from that in the conventional deflected anomaly mediation scenario, but is similar to the one in the gauge mediation scenario. The lightest sparticle is mostly B-ino

  9. Polyarene mediators for mediated redox flow battery

    Science.gov (United States)

    Delnick, Frank M.; Ingersoll, David; Liang, Chengdu

    2018-01-02

    The fundamental charge storage mechanisms in a number of currently studied high energy redox couples are based on intercalation, conversion, or displacement reactions. With exception to certain metal-air chemistries, most often the active redox materials are stored physically in the electrochemical cell stack thereby lowering the practical gravimetric and volumetric energy density as a tradeoff to achieve reasonable power density. In a general embodiment, a mediated redox flow battery includes a series of secondary organic molecules that form highly reduced anionic radicals as reaction mediator pairs for the reduction and oxidation of primary high capacity redox species ex situ from the electrochemical cell stack. Arenes are reduced to stable anionic radicals that in turn reduce a primary anode to the charged state. The primary anode is then discharged using a second lower potential (more positive) arene. Compatible separators and solvents are also disclosed herein.

  10. Making mediation work.

    Science.gov (United States)

    Arif, Zeba

    2016-10-26

    Mediation can be an effective way of solving conflict between staff members. It signifies a willingness for people to work together to discuss their differences in a constructive way, before going down the official grievance route.

  11. Technology-Use Mediation

    DEFF Research Database (Denmark)

    Bansler, Jørgen P.; Havn, Erling C.

    2004-01-01

    Implementation of new computer-mediated communication (CMC) systems in organizations is a complex socio-technical endeavour, involving the mutual adaptation of technology and organization over time. Drawing on the analytic concept of sensemaking, this paper provides a theoretical perspective...... that deepens our understanding of how organizations appropriate new electronic communication media. The paper analyzes how a group of mediators in a large, multinational company adapted a new web-based CMC technology (a virtual workspace) to the local organizational context (and vice versa) by modifying...... features of the technology, providing ongoing support for users, and promoting appropriate conventions of use. We found that these mediators exerted considerable influence on how the technology was established and used in the organization. The mediators were not neutral facilitators of a well...

  12. Understanding Mediation Support

    OpenAIRE

    Lanz, David; Pring, Jamie; von Burg, Corinne; Zeller, Mathias

    2017-01-01

    Recent decades have witnessed increasing institutionalization of mediation support through the establishment of mediation support structures (MSS) within foreign ministries and secretariats of multilateral organizations. This study sheds light on this trend and aims to better understand the emergence, design and development of different MSS. This study analyzes six MSS, namely those established in the United Nations (UN), the Organization for Security and Co-operation in Europe (OSCE), the Eu...

  13. ENVIRONMENTAL CONFLICT MEDIATION

    Directory of Open Access Journals (Sweden)

    GABRIELA G. MIHUT

    2011-04-01

    Full Text Available At a time of global economic crisis followed by resource crisis, a period in which the world seeks alternative resources through eco-investment, environmental conflicts are inevitable. Romania is among the few countries that do not pay enough attention to environmental conflicts and to the advantages to of solving them through mediation procedure. The present paper deals with areas in which conflicts can be applied in environmental mediation and its benefits.

  14. mma: An R Package for Mediation Analysis with Multiple Mediators

    OpenAIRE

    Qingzhao Yu; Bin Li

    2017-01-01

    Mediation refers to the effect transmitted by mediators that intervene in the relationship between an exposure and a response variable. Mediation analysis has been broadly studied in many fields. However, it remains a challenge for researchers to consider complicated associations among variables and to differentiate individual effects from multiple mediators. [1] proposed general definitions of mediation effects that were adaptable to all different types of response (categorical or continuous...

  15. Analysis of multiparty mediation processes

    NARCIS (Netherlands)

    Vuković, Siniša

    2013-01-01

    Crucial challenges for multiparty mediation processes include the achievement of adequate cooperation among the mediators and consequent coordination of their activities in the mediation process. Existing literature goes only as far as to make it clear that successful mediation requires necessary

  16. Mediation: The Wise Advocacy

    Directory of Open Access Journals (Sweden)

    Towseef Ahmad

    2016-01-01

    Full Text Available AbstractAdversarial litigation is not the only means of resolving disputes and settling of claims. There are various options. Alternative means of dispute resolution can save money and time, and can help to anchor and resolve the dispute while exploring valuable good offices, amicable approaches and facilitation. Mediation, as used in law, is a process of managing negotiation by a neutral third party in the form of Alternative Dispute Resolution (ADR, as a convenient way of resolving disputes between two or more parties with speediation processes. On the sidelines typically, a neutral third party, the mediator assists the parties to negotiate a settlement. The term “mediation” broadly refers to any instance in which a neutral third party helps others to reach an amicable and mutually acceptable agreement. More specifically, mediation has a structure, timetable and dynamic approaches that “ordinary” negotiations usually lack. The process helps the parties to flourish the healthy ideas which are different and distinct from the legal rights in a Court of law. It is well known in International Law also and disputants can submit their disputes to mediation in a variety of matters such as commercial, legal, diplomatic, workplace, community and family matters, which assumes a great significance and it is bricolaged within the framework of this article.Keywords: Adversarial, Litigation, Mediation, Negotiation and Amicable.

  17. Immunologically mediated oral diseases.

    Science.gov (United States)

    Jimson, Sudha; Balachader, N; Anita, N; Babu, R

    2015-04-01

    Immune mediated diseases of oral cavity are uncommon. The lesions may be self-limiting and undergo remission spontaneously. Among the immune mediated oral lesions the most important are lichen planus, pemphigus, erythema multiformi, epidermolysis bullosa, systemic lupus erythematosis. Cellular and humoral mediated immunity play a major role directed against epithelial and connective tissue in chronic and recurrent patterns. Confirmatory diagnosis can be made by biopsy, direct and indirect immunoflouresence, immune precipitation and immunoblotting. Therapeutic agents should be selected after thorough evaluation of immune status through a variety of tests and after determining any aggravating or provoking factors. Early and appropriate diagnosis is important for proper treatment planning contributing to better prognosis and better quality of life of patient.

  18. Immunologically mediated oral diseases

    Directory of Open Access Journals (Sweden)

    Sudha Jimson

    2015-01-01

    Full Text Available Immune mediated diseases of oral cavity are uncommon. The lesions may be self-limiting and undergo remission spontaneously. Among the immune mediated oral lesions the most important are lichen planus, pemphigus, erythema multiformi, epidermolysis bullosa, systemic lupus erythematosis. Cellular and humoral mediated immunity play a major role directed against epithelial and connective tissue in chronic and recurrent patterns. Confirmatory diagnosis can be made by biopsy, direct and indirect immunoflouresence, immune precipitation and immunoblotting. Therapeutic agents should be selected after thorough evaluation of immune status through a variety of tests and after determining any aggravating or provoking factors. Early and appropriate diagnosis is important for proper treatment planning contributing to better prognosis and better quality of life of patient.

  19. Causal mediation analysis with multiple causally non-ordered mediators.

    Science.gov (United States)

    Taguri, Masataka; Featherstone, John; Cheng, Jing

    2018-01-01

    In many health studies, researchers are interested in estimating the treatment effects on the outcome around and through an intermediate variable. Such causal mediation analyses aim to understand the mechanisms that explain the treatment effect. Although multiple mediators are often involved in real studies, most of the literature considered mediation analyses with one mediator at a time. In this article, we consider mediation analyses when there are causally non-ordered multiple mediators. Even if the mediators do not affect each other, the sum of two indirect effects through the two mediators considered separately may diverge from the joint natural indirect effect when there are additive interactions between the effects of the two mediators on the outcome. Therefore, we derive an equation for the joint natural indirect effect based on the individual mediation effects and their interactive effect, which helps us understand how the mediation effect works through the two mediators and relative contributions of the mediators and their interaction. We also discuss an extension for three mediators. The proposed method is illustrated using data from a randomized trial on the prevention of dental caries.

  20. Mediation analysis with time varying exposures and mediators.

    Science.gov (United States)

    VanderWeele, Tyler J; Tchetgen Tchetgen, Eric J

    2017-06-01

    In this paper we consider causal mediation analysis when exposures and mediators vary over time. We give non-parametric identification results, discuss parametric implementation, and also provide a weighting approach to direct and indirect effects based on combining the results of two marginal structural models. We also discuss how our results give rise to a causal interpretation of the effect estimates produced from longitudinal structural equation models. When there are time-varying confounders affected by prior exposure and mediator, natural direct and indirect effects are not identified. However, we define a randomized interventional analogue of natural direct and indirect effects that are identified in this setting. The formula that identifies these effects we refer to as the "mediational g-formula." When there is no mediation, the mediational g-formula reduces to Robins' regular g-formula for longitudinal data. When there are no time-varying confounders affected by prior exposure and mediator values, then the mediational g-formula reduces to a longitudinal version of Pearl's mediation formula. However, the mediational g-formula itself can accommodate both mediation and time-varying confounders and constitutes a general approach to mediation analysis with time-varying exposures and mediators.

  1. When Memories are Mediated

    DEFF Research Database (Denmark)

    Frølunde, Lisbeth; Bjerregaard, Mette

    2013-01-01

    that are mediated through stories: told and retold as oral stories through generations, as myths or sagas, or remediated as contemporary documentary film accounts or more fictional film accounts. In these processes of retelling acts of violence, transformations of meanings across time, cultural, social...

  2. Mediated Cultural Memories

    DEFF Research Database (Denmark)

    Frølunde, Lisbeth; Bjerregaard, Mette

    2013-01-01

    generations. Acts of mass violence also construct a sort of looking glass of culturally dominant memories that are mediated through stories: retold as oral stories through generations, as myths or sagas, or remediated in contemporary documentary or fiction films. In these processes of retelling acts...

  3. Cultural mediation in museums

    Directory of Open Access Journals (Sweden)

    Gherghina Boda

    2017-12-01

    Full Text Available If we perceive the museum not only as a place of storing and conserving the patrimony, but also of transmitting it, then we can also see it as a mediator through which cultures can become collective patrimony. Tightly connected to patrimonial appropriation, mediation appears from this perspective as a process and not an end, as it manifests itself in animation, communication and making knowledge popular in relation to a precise patrimony. That is why we can see cultural mediation as a transmission, as a transformation, as an action or social project which aims at creating social bonds, the museum thus being not only a place of meeting for the public with the objects exposed, but also as a place of meeting between different cultures. Thus, cultural mediation presents itself as the most efficient means for access to culture of all categories of the public, situated as the crossroads of culture, continuous education and entertainment and is inscribed in the field of informal education.

  4. The Bensberg Mediation Model

    Directory of Open Access Journals (Sweden)

    Raluca - Marilena Mihalcioiu

    2011-05-01

    Full Text Available The basis of the conflict through the mediation represents the objectives and procedures ofmediation, mediation of a conflict. The conflict will not be disclosed to others, but the parties will be creditedthe authority to resolve the conflict, the conflict among themselves with the help of a mediator. The disputeshould be resolved by the parties with help of a third party. The parties in conflict (it may be several personsare jointly responsible for the solution. They seek together a way that leads to long-term settlement of theconflict. The assumption of responsibility in this process strengthens the confidence and the importance oftheir decision. Important is that losers usually have no peace, because they are out for revenge. Winners don’tneed peace. If both parties lose, remains disappointing, with the understanding of which the conflict isresolved, will understand each other better developed. Reconciliation is therefore a longer-term goal.Conflicts also help to clarify roles. The paper presents Bensberg Model of Mediation, because this isdeveloped as a win win solution and his possible implementation in Romanian schools.

  5. Axionic mirage mediation

    International Nuclear Information System (INIS)

    Nakamura, Shuntaro; Okumura, Ken-ichi; Yamaguchi, Masahiro

    2008-01-01

    Although mirage mediation is one of the most plausible mediation mechanisms of supersymmetry breaking, it suffers from two crucial problems. One is the μ/Bμ problem, and the second is the cosmological one. The former stems from the fact that the B parameter tends to be comparable with the gravitino mass, which is 2 orders of magnitude larger than the other soft masses. The latter problem is caused by the decay of the modulus whose branching ratio into the gravitino pair is sizable. In this paper, we propose a model of mirage mediation, in which Peccei-Quinn symmetry is incorporated. In this axionic mirage mediation, it is shown that the Peccei-Quinn symmetry breaking scale is dynamically determined around 10 10 GeV to 10 12 GeV due to the supersymmetry breaking effects, and the μ problem can be solved naturally. Furthermore, in our model, the lightest supersymmetric particle (LSP) is the axino, that is, the superpartner of the axion. The overabundance of the LSPs due to decays of the modulus/gravitino, which is the most serious cosmological difficulty in the mirage mediation, can be avoided if the axino is sufficiently light. The next-LSPs (NLSPs) produced by the gravitino decay eventually decay into the axino LSPs, yielding the dominant component of the axinos remaining today. It is shown that the axino with a mass of O(100) MeV is naturally realized, which can constitute the dark matter of the Universe, with a free-streaming length of the order of 0.1 Mpc. The saxion, the real scalar component of the axion supermultiplet, can also be cosmologically harmless due to the dilution of the modulus decay. The lifetime of the NLSP is relatively long, but much shorter than 1 sec, when the big-bang nucleosynthesis commences. The decay of the NLSP would provide intriguing collider signatures

  6. Interventional Effects for Mediation Analysis with Multiple Mediators.

    Science.gov (United States)

    Vansteelandt, Stijn; Daniel, Rhian M

    2017-03-01

    The mediation formula for the identification of natural (in)direct effects has facilitated mediation analyses that better respect the nature of the data, with greater consideration of the need for confounding control. The default assumptions on which it relies are strong, however. In particular, they are known to be violated when confounders of the mediator-outcome association are affected by the exposure. This complicates extensions of counterfactual-based mediation analysis to settings that involve repeatedly measured mediators, or multiple correlated mediators. VanderWeele, Vansteelandt, and Robins introduced so-called interventional (in)direct effects. These can be identified under much weaker conditions than natural (in)direct effects, but have the drawback of not adding up to the total effect. In this article, we adapt their proposal to achieve an exact decomposition of the total effect, and extend it to the multiple mediator setting. Interestingly, the proposed effects capture the path-specific effects of an exposure on an outcome that are mediated by distinct mediators, even when-as often-the structural dependence between the multiple mediators is unknown, for instance, when the direction of the causal effects between the mediators is unknown, or there may be unmeasured common causes of the mediators.

  7. Mediation analysis with multiple versions of the mediator.

    Science.gov (United States)

    Vanderweele, Tyler J

    2012-05-01

    The causal inference literature has provided definitions of direct and indirect effects based on counterfactuals that generalize the approach found in the social science literature. However, these definitions presuppose well-defined hypothetical interventions on the mediator. In many settings, there may be multiple ways to fix the mediator to a particular value, and these various hypothetical interventions may have very different implications for the outcome of interest. In this paper, we consider mediation analysis when multiple versions of the mediator are present. Specifically, we consider the problem of attempting to decompose a total effect of an exposure on an outcome into the portion through the intermediate and the portion through other pathways. We consider the setting in which there are multiple versions of the mediator but the investigator has access only to data on the particular measurement, not information on which version of the mediator may have brought that value about. We show that the quantity that is estimated as a natural indirect effect using only the available data does indeed have an interpretation as a particular type of mediated effect; however, the quantity estimated as a natural direct effect, in fact, captures both a true direct effect and an effect of the exposure on the outcome mediated through the effect of the version of the mediator that is not captured by the mediator measurement. The results are illustrated using 2 examples from the literature, one in which the versions of the mediator are unknown and another in which the mediator itself has been dichotomized.

  8. Current Directions in Mediation Analysis

    Science.gov (United States)

    MacKinnon, David P.; Fairchild, Amanda J.

    2010-01-01

    Mediating variables continue to play an important role in psychological theory and research. A mediating variable transmits the effect of an antecedent variable on to a dependent variable, thereby providing more detailed understanding of relations among variables. Methods to assess mediation have been an active area of research for the last two decades. This paper describes the current state of methods to investigate mediating variables. PMID:20157637

  9. Current Directions in Mediation Analysis

    OpenAIRE

    MacKinnon, David P.; Fairchild, Amanda J.

    2009-01-01

    Mediating variables continue to play an important role in psychological theory and research. A mediating variable transmits the effect of an antecedent variable on to a dependent variable, thereby providing more detailed understanding of relations among variables. Methods to assess mediation have been an active area of research for the last two decades. This paper describes the current state of methods to investigate mediating variables.

  10. Dissociation in mediation

    Directory of Open Access Journals (Sweden)

    Daniela Muraru

    2008-01-01

    Full Text Available This paper approaches several texts that are part of the so-called discourse of mediation, adopting a pragma-dialectical perspective of the theory of dissociation. It is an attempt to identify the uses of dissociative patterns, with special emphasis on the indicators of dissociation. The paper investigates the various uses of the concept of dissociation as a discursive technique in the argumentation on the different aspects that are involved in international conflict, such as the discussion of the notion of peace. The purpose is to identify the role of dissociation, as a device strategically used by the mediator to help the parties minimize the disagreement space, and come to a conflict resolution.

  11. [Mediation in schools].

    Science.gov (United States)

    Mickley, Angela

    2006-01-01

    In this article the guiding questions concern the objectives and effectiveness of introducing mediation into an existing school culture of dominance, competition and selection. In addition the necessity will be shown of combining conflict resolution with organisational development and the introduction of a consensual ethics and behaviour code to attain sustainable results in creating a constructive and healthy school environment. Given scarce resources and little time the decisive role of artistic methods will be looked at in providing young people with flexible methods of expressing and negotiating their interests in a changing environment of values and power structures. Some aspects of the development of nonviolent communication, conflict resolution and mediation methods in schools in Germany will be focused on with special emphasis on the type of intervention used and its long term sustainable effects.

  12. Church mediation - een vak apart

    NARCIS (Netherlands)

    Annelies Klinefelter; dr Hans A.J. Jonker

    2009-01-01

    Welke rol kan mediation in de kerk spelen in de diverse geledingen en specifieke activiteiten? In dit artikel wordt ingegaan op kerkelijke conflicten, gelaagdheid in church mediation, en specifieke dilemma's van church mediation. Daarnaast komen enkele benaderingen aan bod zoals: helende

  13. The Mediatization of Philanthropy

    OpenAIRE

    Mitchell, Matthew

    2014-01-01

    This study seeks to better understand the motivations and mechanics of individuals contributing to nonprofits organizations today.  Through the prism of our highly mediatized (Hjarvard, 2008) social environment, this study examines the individual motivations and actions of cause-champions running in the 2013 NYC marathon and fundraising through social media and offline on behalf of the Michael J Fox Foundation (MJFF).  To gain the necessary detail and understanding of these micro-actions of a...

  14. Teachers as mediators

    DEFF Research Database (Denmark)

    Dorf, Hans; Kelly, Peter; Hohmann, Ulrike

    2012-01-01

    Within the context of lower secondary English teaching in South West England, this study identifies in broad terms the competing goals between which English teachers mediate and the explicit and hidden tensions that result. To understand the interactions of competing goals, teachers’ goal...... and cultural influences on practice. Yet the teachers observed moved smoothly between goal-oriented behaviours in a continuous and comfortable style, easily and without reflecting any tensions between them. Thus, this article elaborates an account of situated English teaching....

  15. mma: An R Package for Mediation Analysis with Multiple Mediators

    Directory of Open Access Journals (Sweden)

    Qingzhao Yu

    2017-04-01

    Full Text Available Mediation refers to the effect transmitted by mediators that intervene in the relationship between an exposure and a response variable. Mediation analysis has been broadly studied in many fields. However, it remains a challenge for researchers to consider complicated associations among variables and to differentiate individual effects from multiple mediators. [1] proposed general definitions of mediation effects that were adaptable to all different types of response (categorical or continuous, exposure, or mediation variables. With these definitions, multiple mediators of different types can be considered simultaneously, and the indirect effects carried by individual mediators can be separated from the total effect. Moreover, the derived mediation analysis can be performed with general predictive models. That is, the relationships among variables can be modeled using not only generalized linear models but also nonparametric models such as the Multiple Additive Regression Trees. Therefore, more complicated variable transformations and interactions can be considered in analyzing the mediation effects. The proposed method is realized by the R package 'mma'. We illustrate in this paper the proposed method and how to use 'mma' to estimate mediation effects and make inferences.

  16. Causal Mediation Analysis of Survival Outcome with Multiple Mediators.

    Science.gov (United States)

    Huang, Yen-Tsung; Yang, Hwai-I

    2017-05-01

    Mediation analyses have been a popular approach to investigate the effect of an exposure on an outcome through a mediator. Mediation models with multiple mediators have been proposed for continuous and dichotomous outcomes. However, development of multimediator models for survival outcomes is still limited. We present methods for multimediator analyses using three survival models: Aalen additive hazard models, Cox proportional hazard models, and semiparametric probit models. Effects through mediators can be characterized by path-specific effects, for which definitions and identifiability assumptions are provided. We derive closed-form expressions for path-specific effects for the three models, which are intuitively interpreted using a causal diagram. Mediation analyses using Cox models under the rare-outcome assumption and Aalen additive hazard models consider effects on log hazard ratio and hazard difference, respectively; analyses using semiparametric probit models consider effects on difference in transformed survival time and survival probability. The three models were applied to a hepatitis study where we investigated effects of hepatitis C on liver cancer incidence mediated through baseline and/or follow-up hepatitis B viral load. The three methods show consistent results on respective effect scales, which suggest an adverse estimated effect of hepatitis C on liver cancer not mediated through hepatitis B, and a protective estimated effect mediated through the baseline (and possibly follow-up) of hepatitis B viral load. Causal mediation analyses of survival outcome with multiple mediators are developed for additive hazard and proportional hazard and probit models with utility demonstrated in a hepatitis study.

  17. Immune mediated liver failure.

    Science.gov (United States)

    Wang, Xiaojing; Ning, Qin

    2014-01-01

    Liver failure is a clinical syndrome of various etiologies, manifesting as jaundice, encephalopathy, coagulopathy and circulatory dysfunction, which result in subsequent multiorgan failure. Clinically, liver failure is classified into four categories: acute, subacute, acute-on-chronic and chronic liver failure. Massive hepatocyte death is considered to be the core event in the development of liver failure, which occurs when the extent of hepatocyte death is beyond the liver regenerative capacity. Direct damage and immune-mediated liver injury are two major factors involved in this process. Increasing evidence has suggested the essential role of immune-mediated liver injury in the pathogenesis of liver failure. Here, we review the evolved concepts concerning the mechanisms of immune-mediated liver injury in liver failure from human and animal studies. Both innate and adaptive immunity, especially the interaction of various immune cells and molecules as well as death receptor signaling system are discussed. In addition, we highlight the concept of "immune coagulation", which has been shown to be related to the disease progression and liver injury exacerbation in HBV related acute-on-chronic liver failure.

  18. Lopsided Gauge Mediation

    CERN Document Server

    De Simone, Andrea; Giudice, Gian Francesco; Pappadopulo, Duccio; Rattazzi, Riccardo

    2011-01-01

    It has been recently pointed out that the unavoidable tuning among supersymmetric parameters required to raise the Higgs boson mass beyond its experimental limit opens up new avenues for dealing with the so called $\\mu$-$B_\\mu$ problem of gauge mediation. In fact, it allows for accommodating, with no further parameter tuning, large values of $B_\\mu$ and of the other Higgs-sector soft masses, as predicted in models where both $\\mu$ and $B_\\mu$ are generated at one-loop order. This class of models, called Lopsided Gauge Mediation, offers an interesting alternative to conventional gauge mediation and is characterized by a strikingly different phenomenology, with light higgsinos, very large Higgs pseudoscalar mass, and moderately light sleptons. We discuss general parametric relations involving the fine-tuning of the model and various observables such as the chargino mass and the value of $\\tan\\beta$. We build an explicit model and we study the constraints coming from LEP and Tevatron. We show that in spite of ne...

  19. What carries a mediation process? Configural analysis of mediation.

    Science.gov (United States)

    von Eye, Alexander; Mun, Eun Young; Mair, Patrick

    2009-09-01

    Mediation is a process that links a predictor and a criterion via a mediator variable. Mediation can be full or partial. This well-established definition operates at the level of variables even if they are categorical. In this article, two new approaches to the analysis of mediation are proposed. Both of these approaches focus on the analysis of categorical variables. The first involves mediation analysis at the level of configurations instead of variables. Thus, mediation can be incorporated into the arsenal of methods of analysis for person-oriented research. Second, it is proposed that Configural Frequency Analysis (CFA) can be used for both exploration and confirmation of mediation relationships among categorical variables. The implications of using CFA are first that mediation hypotheses can be tested at the level of individual configurations instead of variables. Second, this approach leaves the door open for different types of mediation processes to exist within the same set. Using a data example, it is illustrated that aggregate-level analysis can overlook mediation processes that operate at the level of individual configurations.

  20. Urban Songlines as Mediator

    DEFF Research Database (Denmark)

    Corlin, Anne

    2016-01-01

    The aim of this paper is to present an investigation of the method The Urban Songlines Book and how it works as a mediator for mapping the experienced space. The method contains a combination of aerial maps, photographs, and interviews as a way to understand the respondent´s use, relations...... and experiences of their neighborhood and the city. Through a presentation of the origin of the method, a description of the conducted study, and an analysis of the process in relation to theories about participatory design, social design, ANT and architectural sociology, the paper reveals how this method...

  1. Sociocultural mediators of remembering

    DEFF Research Database (Denmark)

    Wagoner, Brady; Gillespie, Alex

    2014-01-01

    , questioning and deferring contribute to the transformation and conventionalization of the material. These diverse sociocultural mediators are integrated into a partially coherent recollection by participants self-reflecting, or as Bartlett termed it, turning around upon their schemas. We demonstrate...... that this self-reflection is both a social and a psychological process, occurring because participants are responding to their own utterances in the same way that they respond to the utterances of other people. These empirical findings are used to make a case for using discursive data to look not only...

  2. DNA-Mediated Electrochemistry

    Science.gov (United States)

    Gorodetsky, Alon A.; Buzzeo, Marisa C.

    2009-01-01

    The base pair stack of DNA has been demonstrated as a medium for long range charge transport chemistry both in solution and at DNA-modified surfaces. This chemistry is exquisitely sensitive to structural perturbations in the base pair stack as occur with lesions, single base mismatches, and protein binding. We have exploited this sensitivity for the development of reliable electrochemical assays based on DNA charge transport at self-assembled DNA monolayers. Here we discuss the characteristic features, applications, and advantages of DNA-mediated electrochemistry. PMID:18980370

  3. Holographic Gauge Mediation

    Energy Technology Data Exchange (ETDEWEB)

    Benini, Francesco; /Princeton U.; Dymarsky, Anatoly; /Stanford U., ITP; Franco, Sebastian; /Santa Barbara, KITP; Kachru, Shamit; Simic, Dusan; /Stanford U., ITP /SLAC; Verlinde, Herman; /Princeton, Inst. Advanced Study

    2009-06-19

    We discuss gravitational backgrounds where supersymmetry is broken at the end of a warped throat, and the SUSY-breaking is transmitted to the Standard Model via gauginos which live in (part of) the bulk of the throat geometry. We find that the leading effect arises from splittings of certain 'messenger mesons,' which are adjoint KK-modes of the D-branes supporting the Standard Model gauge group. This picture is a gravity dual of a strongly coupled field theory where SUSY is broken in a hidden sector and transmitted to the Standard Model via a relative of semi-direct gauge mediation.

  4. 45 CFR 16.18 - Mediation.

    Science.gov (United States)

    2010-10-01

    ... 45 Public Welfare 1 2010-10-01 2010-10-01 false Mediation. 16.18 Section 16.18 Public Welfare... BOARD § 16.18 Mediation. (a) In cases pending before the Board. If the Board decides that mediation... mediation techniques and will provide or assist in selecting a mediator. The mediator may take any steps...

  5. Interventional effects for mediation analysis with multiple mediators

    OpenAIRE

    Vansteelandt, Stijn; Daniel, Rhian M.

    2017-01-01

    The mediation formula for the identification of natural (in)direct effects has facilitated mediation analyses that better respect the nature of the data, with greater consideration of the need for confounding control. The default assumptions on which it relies are strong, however. In particular, they are known to be violated when confounders of the mediator–outcome association are affected by the exposure. This complicates extensions of counterfactual-based mediation analysis to settings that...

  6. Interpreter-mediated dentistry.

    Science.gov (United States)

    Bridges, Susan; Drew, Paul; Zayts, Olga; McGrath, Colman; Yiu, Cynthia K Y; Wong, H M; Au, T K F

    2015-05-01

    The global movements of healthcare professionals and patient populations have increased the complexities of medical interactions at the point of service. This study examines interpreter mediated talk in cross-cultural general dentistry in Hong Kong where assisting para-professionals, in this case bilingual or multilingual Dental Surgery Assistants (DSAs), perform the dual capabilities of clinical assistant and interpreter. An initial language use survey was conducted with Polyclinic DSAs (n = 41) using a logbook approach to provide self-report data on language use in clinics. Frequencies of mean scores using a 10-point visual analogue scale (VAS) indicated that the majority of DSAs spoke mainly Cantonese in clinics and interpreted for postgraduates and professors. Conversation Analysis (CA) examined recipient design across a corpus (n = 23) of video-recorded review consultations between non-Cantonese speaking expatriate dentists and their Cantonese L1 patients. Three patterns of mediated interpreting indicated were: dentist designated expansions; dentist initiated interpretations; and assistant initiated interpretations to both the dentist and patient. The third, rather than being perceived as negative, was found to be framed either in response to patient difficulties or within the specific task routines of general dentistry. The findings illustrate trends in dentistry towards personalized care and patient empowerment as a reaction to product delivery approaches to patient management. Implications are indicated for both treatment adherence and the education of dental professionals. Copyright © 2015 Elsevier Ltd. All rights reserved.

  7. Mediation Analysis: A Practitioner's Guide.

    Science.gov (United States)

    VanderWeele, Tyler J

    2016-01-01

    This article provides an overview of recent developments in mediation analysis, that is, analyses used to assess the relative magnitude of different pathways and mechanisms by which an exposure may affect an outcome. Traditional approaches to mediation in the biomedical and social sciences are described. Attention is given to the confounding assumptions required for a causal interpretation of direct and indirect effect estimates. Methods from the causal inference literature to conduct mediation in the presence of exposure-mediator interactions, binary outcomes, binary mediators, and case-control study designs are presented. Sensitivity analysis techniques for unmeasured confounding and measurement error are introduced. Discussion is given to extensions to time-to-event outcomes and multiple mediators. Further flexible modeling strategies arising from the precise counterfactual definitions of direct and indirect effects are also described. The focus throughout is on methodology that is easily implementable in practice across a broad range of potential applications.

  8. A higher form (of) mediation

    International Nuclear Information System (INIS)

    Verlinde, Herman; Wang, L-T; Yavin, Itay; Wijnholt, Martijn

    2008-01-01

    We exhibit a simple and robust mechanism for bulk mediation of supersymmetry breaking between hidden and visible sectors localized on geometrically separated D-branes in type II string theory. The mediation proceeds via RR p-forms that couple via linear Chern-Simons terms to the abelian vector bosons on the branes. From a 4-d low energy perspective, the mechanism reduces to U(1) mediation

  9. Mediating Trust in Terrorism Coverage

    DEFF Research Database (Denmark)

    Mogensen, Kirsten

    crisis. While the framework is presented in the context of television coverage of a terror-related crisis situation, it can equally be used in connection with all other forms of mediated trust. Key words: National crisis, risk communication, crisis management, television coverage, mediated trust.......Mass mediated risk communication can contribute to perceptions of threats and fear of “others” and/or to perceptions of trust in fellow citizens and society to overcome problems. This paper outlines a cross-disciplinary holistic framework for research in mediated trust building during an acute...

  10. Substrate mediated enzyme prodrug therapy

    DEFF Research Database (Denmark)

    Fejerskov, Betina; Jarlstad Olesen, Morten T; Zelikin, Alexander N

    2017-01-01

    Substrate mediated enzyme prodrug therapy (SMEPT) is a biomedical platform developed to perform a localized synthesis of drugs mediated by implantable biomaterials. This approach combines the benefits and at the same time offers to overcome the drawbacks for traditional pill-based drug administra......Substrate mediated enzyme prodrug therapy (SMEPT) is a biomedical platform developed to perform a localized synthesis of drugs mediated by implantable biomaterials. This approach combines the benefits and at the same time offers to overcome the drawbacks for traditional pill-based drug...

  11. The Strategic Mediator

    DEFF Research Database (Denmark)

    Rossignoli, Cecilia; Carugati, Andrea; Mola, Lapo

    2009-01-01

    process. Through the study of services evolving over time we show that, as marketplaces support increasingly complex business processes, the market participants begin to privilege the well connected small number to the convenience of the openness to the entire market. The participants see the marketplace......The last 10 years have witnessed the emergence of electronic marketplaces as players that leverage new technologies to facilitate B2B internet-mediated collaborative business. Nowadays these players are augmenting their services from simple intermediation to include new inter......-organizational relationships. The interest of this paper is to investigate the shift in the role and evolution of services proposed by e-marketplaces in response to the demands of the market participants. We carried out a longitudinal qualitative field study of an e-marketplace providing the outsourcing of the procurement...

  12. Mediating Potency and Fear

    DEFF Research Database (Denmark)

    Christiansen, Steen Ledet

    2018-01-01

    Action movies participate in the administration of fear [Virilio, P., 2012. The administration of fear. Translated by Ames Hodges. Los Angeles, CA: Semiotext(e)], and the networked affects of contemporary warfare [Anderson, B., 2013. Targeting affective life from above: morale and airpower. In: P......’ [Shaviro, S., 2010. Post-cinematic affect. Winchester: Zero Books]. These intensity effects mediate between the age of terror's ecology of fear [Massumi, Brian, 2002. Parables for the virtual: movement, affect, sensation. Durham: Duke University Press] and our bodies. Rather than producing fear, action...... movies work to dispel fear by producing potency and bolstering resolve. We can thus understand action movies as participating in the biopolitical effects of contemporary warfare. Affect is globalized and intensified through action movies’ aesthetics, with the aim of producing a kind of drone subject...

  13. Den sundhedsfremmende mediator

    DEFF Research Database (Denmark)

    Læssøe, Jeppe

    2009-01-01

      Mediatorer er en relativ ny aktør-type og job-funktion, som passer godt ind i det dynamiske videns- og netværkssamfund. I sundhedsfremmende arbejde med vægt på borgernes deltagelse kan mediatorer spille en nøglerolle. Det er derfor vigtigt begrebsmæssigt at kunne skelne mellem forskellige typer...... mediering samt mellem forskellige mediator-roller og tilhørsforhold. Det er også vigtigt at være bevidst om de centrale kvaliteter, risici og dilemmaer, som mediering indebærer i forhold til involvering af borgerne. Denne artikel rummer et bud på en sådan nuanceret begrebsliggørelse og refleksion, relateret...

  14. Soluble lymphocytic mediators

    Science.gov (United States)

    Pick, E.

    1974-01-01

    The effect of a number of drugs on the production of macrophage migration inhibitory factor (MIF) by antigen-stimulated sensitized guinea-pig lymph node cells was studied. The drugs were present during the entire culture period and eliminated from supernatants by dialysis. It was found that MIF secretion is inhibited by exogenous dibutyryl cyclic AMP and by theophylline and chlorphenesin, two agents raising the endogenous level of cyclic AMP. On the other hand, isoproterenol, which stimulates cyclic AMP generation in several tissues, did not block MIF production. The formation of the mediator was also suppressed by the microfilament-affecting drug, cytochalasin B. The microtubular disruptive agents, colchicine and vinblastine sulphate, did not influence MIF production. It is concluded that: (a) endogenous cyclic AMP may act as a regulator of MIF production; (b) the activity of contractile microfilaments is probably required for MIF formation; and (c) microtubules are not involved in the secretory process. PMID:4369184

  15. Protein- mediated enamel mineralization

    Science.gov (United States)

    Moradian-Oldak, Janet

    2012-01-01

    Enamel is a hard nanocomposite bioceramic with significant resilience that protects the mammalian tooth from external physical and chemical damages. The remarkable mechanical properties of enamel are associated with its hierarchical structural organization and its thorough connection with underlying dentin. This dynamic mineralizing system offers scientists a wealth of information that allows the study of basic principals of organic matrix-mediated biomineralization and can potentially be utilized in the fields of material science and engineering for development and design of biomimetic materials. This chapter will provide a brief overview of enamel hierarchical structure and properties as well as the process and stages of amelogenesis. Particular emphasis is given to current knowledge of extracellular matrix protein and proteinases, and the structural chemistry of the matrix components and their putative functions. The chapter will conclude by discussing the potential of enamel for regrowth. PMID:22652761

  16. Mediating environmental disputes

    Energy Technology Data Exchange (ETDEWEB)

    Lake, L.M.

    1977-09-01

    Environmental disputes and lawsuits are examined. Site-specific disputes focus on visible physical phenomena, such as a power plant or local river, and have an immediacy and intensity about them that make it politically hazardous for public officials to assume responsibility for resolving them. As new precedents in environmental case law become less frequent and the number of disputes increases, alternative processes for environmental conflict resolution, such as third-party intervention, become appropriate. Third-party intervention techniques of fact finding, conflict avoidance, conciliation and mediation have been applied to international, labor, prison, school, racial, and hospital disputes. Underlying concepts are described. Two case studies, the Snoqualmie Dam dispute in Washington and the West Side Highway dispute in New York City, illustrate the basic elements associated with third-party intervention. 1 map, 17 references.

  17. Mediatization and Government Communication

    DEFF Research Database (Denmark)

    Laursen, Bo; Valentini, Chiara

    2015-01-01

    do not tend to get a media coverage that matches the EU’s considerable influence on European citizens’ daily lives. This study, which is based on in-depth interviews with European Parliament press officers, concludes that these professionals are indeed attuned to a “media logic......Social actors see exposure in the news media as attractive for publicity purposes and are under pressure to adapt their press work to a “media logic” to be attractive sources for journalists and editors. This article investigates the European Parliament’s press officers’ professional practices...... in the light of mediatization and government communication theories. Without one pan-European public sphere, the European Parliament, like the other European Union (EU) institutions, competes with national actors for the news media’s attention in the EU’s twenty-eight national public spheres, where EU affairs...

  18. The mediation procedure in Romania

    Directory of Open Access Journals (Sweden)

    Alexandrina Zaharia

    2009-06-01

    Full Text Available The mediation activity as an alternative way of solving conflicts occupies an important place in modernsociety. Currently, the mediation reached its maturity worldwide being adopted without reservations.The future of solving conflicts is undoubtedly closely related to mediation. XXth century is the century of solvingconflicts amiably outside the court room. In Romania and the mediation profession were regulated by the Law no.192/2006, on the basis of the idea that mediation is one of the major themes of the reform strategy of the judicialsystem 2005-2007. By adopting the mentioned law it was followed the idea of reducing the volume of activitycourts, and therefore, relieve them of as many cases, with the direct effect on the quality of justice. Mediation is avoluntary process in which the parties with a neutral and impartial third party, without power of decision - themediator - who is qualified to assist the parties to negotiate, facilitating the communication between them andhelping them to reach a unanimous effective and sustainable agreement. The parties may resort to mediation beforeor after triggering a trial. Mediation can be applied, in principle, on any type of conflict. However, theRomanian legislator has established special stipulations on conflict mediation in criminal, civil and familylaw. Although not expressly provided, the stipulations regarding the civil conflicts and also apply to commercialconflicts. Therefore, the mediation is applicable to most types of lawsuits, except those relating to personalrights. As a "win- win" principle, the mediation does not convert any of the parties defeated or victorious; allthose involved have gained by applying this procedure.

  19. Anomaly mediation deformed by axion

    Energy Technology Data Exchange (ETDEWEB)

    Nakayama, Kazunori, E-mail: kazunori@hep-th.phys.s.u-tokyo.ac.jp [Department of Physics, University of Tokyo, Bunkyo-ku, Tokyo 113-0033 (Japan); Kavli Institute for the Physics and Mathematics of the Universe, University of Tokyo, Kashiwa 277-8583 (Japan); Yanagida, Tsutomu T. [Kavli Institute for the Physics and Mathematics of the Universe, University of Tokyo, Kashiwa 277-8583 (Japan)

    2013-05-13

    We show that in supersymmetric axion models the axion supermultiplet obtains a sizable F-term due to a non-supersymmetric dynamics and it generally gives the gaugino masses comparable to the anomaly mediation contribution. Thus the gaugino mass relation predicted by the anomaly mediation effect can be significantly modified in the presence of axion to solve the strong CP problem.

  20. Theorizing with/out "Mediators".

    Science.gov (United States)

    Roth, Wolff-Michael; Jornet, Alfredo

    2017-01-05

    Mediation is one of the most often cited concepts in current cultural-historical theory literature, in which cultural actions and artifacts are often characterized as mediators standing between situational stimuli and behavioral responses. Most often presented as a means to overcome Cartesian dualism between subject and object, and between individual and society, some scholars have nonetheless raised criticism suggesting that such mediators are problematic for a dialectical psychology that takes a unit analysis (monist) approach. In fact, Spinoza develops a monist theory of mind and body that goes without and even excludes every form of mediation. In this study, we follow up on the latter criticisms and explore what we consider to be problematic uses of the notion of mediation as an analytical construct in the literature. We elaborate an empirically grounded discussion on the ways the concept of mediation may lead to dualistic readings; and we offer an alternative account where the notion of mediator is not needed. We conclude discussing prospects for and implications of a cultural-historical theory where the notion of mediation no longer is invoked to account for human action and development.

  1. Comments on general gauge mediation

    International Nuclear Information System (INIS)

    Intriligator, Kenneth; Sudano, Matthew

    2008-01-01

    There has been interest in generalizing models of gauge mediation of supersymmetry breaking. As shown by Meade, Seiberg, and Shih (MSS), the soft masses of general gauge mediation can be expressed in terms of the current two-point functions of the susy-breaking sector. We here give a simple extension of their result which provides, for general gauge mediation, the full effective potential for squark pseudo-D-flat directions. The effective potential reduces to the sfermion soft masses near the origin, and the full potential, away from the origin, can be useful for cosmological applications. We also generalize the soft masses and effective potential to allow for general gauge mediation by Higgsed gauge groups. Finally, we discuss general gauge mediation in the limit of small F-terms, and how the results of MSS connect with the analytic continuation in superspace results, based on a spurion analysis.

  2. Practical Guide to Civil Mediation

    CERN Document Server

    2006-01-01

    The Permanent Mission of Switzerland has informed CERN that the Département des Institutions of the Republic and Canton of Geneva and the Groupement suisse des Magistrats pour la médiation (GEMME) - Swiss Association of Magistrates for Mediation have published a multilingual Practical Guide to Civil Mediation (including English). In this context, the Swiss Mission has underlined the benefits of resorting to mediation, especially for the personnel of international organizations, and which the Secretary-General of the GEMME has summarised as follows: it is a private process not requiring the waiver of the parties' immunities; the confidentiality of the mediation process is guaranteed both by the mediator and the parties to it; the search for an amicable settlement does not need to be determined by reference to law (provided that public order is respected); the process is faster (2 to 3 sessions), less costly and more flexible than civil or arbitration procedures; in order to reinforce the agreeme...

  3. Practical Guide to Civil Mediation

    CERN Multimedia

    2006-01-01

    The Permanent Mission of Switzerland has informed CERN that the Département des Institutions of the Republic and Canton of Geneva and the Groupement suisse des Magistrats pour la médiation (GEMME) - Swiss Association of Magistrates for Mediation have published a multilingual Practical Guide to Civil Mediation (including English). In this context, the Swiss Mission has underlined the benefits of resorting to mediation, especially for the personnel of International Organizations, and which the Secretary-General of the GEMME has summarised as follows: it is a private process not requiring the waiver of the parties' immunities; the confidentiality of the mediation process is guaranteed both by the mediator and the parties to it; the search for an amicable settlement does not need to be determined by reference to law (provided that public order is respected); the process is faster (2 to 3 sessions), less costly and more flexible than civil or arbitration procedures; in order to reinforce the agreem...

  4. 29 CFR 35.32 - Mediation.

    Science.gov (United States)

    2010-07-01

    ... 29 Labor 1 2010-07-01 2010-07-01 true Mediation. 35.32 Section 35.32 Labor Office of the Secretary... Mediation. (a) Referral to mediation. CRC will promptly refer to the Federal Mediation and Conciliation Service or the mediation agency designated by the Secretary of Health and Human Services under 45 CFR part...

  5. 22 CFR 143.33 - Mediation.

    Science.gov (United States)

    2010-04-01

    ... 22 Foreign Relations 1 2010-04-01 2010-04-01 false Mediation. 143.33 Section 143.33 Foreign... Mediation. (a) Referral of complaints for mediation. The agency will refer to the Federal Mediation and... participate in the mediation process to the extent necessary to reach an agreement or make an informed...

  6. 29 CFR 1203.1 - Mediation services.

    Science.gov (United States)

    2010-07-01

    ... 29 Labor 4 2010-07-01 2010-07-01 false Mediation services. 1203.1 Section 1203.1 Labor Regulations Relating to Labor (Continued) NATIONAL MEDIATION BOARD APPLICATIONS FOR SERVICE § 1203.1 Mediation services. Applications for the mediation services of the National Mediation Board under section 5, First, of the Railway...

  7. 34 CFR 81.13 - Mediation.

    Science.gov (United States)

    2010-07-01

    ... 34 Education 1 2010-07-01 2010-07-01 false Mediation. 81.13 Section 81.13 Education Office of the... Mediation. (a) Voluntary mediation is available for proceedings that are pending before the OALJ. (b) A... mediation by filing a motion with the ALJ assigned to the case. The OALJ arranges for a mediator if the...

  8. 24 CFR 3288.35 - Mediation.

    Science.gov (United States)

    2010-04-01

    ... 24 Housing and Urban Development 5 2010-04-01 2010-04-01 false Mediation. 3288.35 Section 3288.35...-Administered States § 3288.35 Mediation. (a) Mediator. The dispute resolution provider will provide for the... identifies any other party that should be included in the mediation, the mediator will contact the other...

  9. 44 CFR 7.942 - Mediation.

    Science.gov (United States)

    2010-10-01

    ... 44 Emergency Management and Assistance 1 2010-10-01 2010-10-01 false Mediation. 7.942 Section 7..., Conciliation, and Enforcement Procedures § 7.942 Mediation. (a) FEMA will promptly refer to a mediation agency... participate in the mediation process to the extent necessary to reach an agreement or for the mediator to make...

  10. 32 CFR 776.38 - Mediation.

    Science.gov (United States)

    2010-07-01

    ... 32 National Defense 5 2010-07-01 2010-07-01 false Mediation. 776.38 Section 776.38 National... Professional Conduct § 776.38 Mediation. (a) Mediation: (1) A covered attorney may act as a mediator between... mediation, including the advantages and risks involved, and the effect on the attorney-client...

  11. 29 CFR 1202.1 - Mediation.

    Science.gov (United States)

    2010-07-01

    ... 29 Labor 4 2010-07-01 2010-07-01 false Mediation. 1202.1 Section 1202.1 Labor Regulations Relating to Labor (Continued) NATIONAL MEDIATION BOARD RULES OF PROCEDURE § 1202.1 Mediation. The mediation..., or where conferences are refused. The National Mediation Board may proffer its services in case any...

  12. Microbially mediated mineral carbonation

    Science.gov (United States)

    Power, I. M.; Wilson, S. A.; Dipple, G. M.; Southam, G.

    2010-12-01

    Mineral carbonation involves silicate dissolution and carbonate precipitation, which are both natural processes that microorganisms are able to mediate in near surface environments (Ferris et al., 1994; Eq. 1). (Ca,Mg)SiO3 + 2H2CO3 + H2O → (Ca,Mg)CO3 + H2O + H4SiO4 + O2 (1) Cyanobacteria are photoautotrophs with cell surface characteristics and metabolic processes involving inorganic carbon that can induce carbonate precipitation. This occurs partly by concentrating cations within their net-negative cell envelope and through the alkalinization of their microenvironment (Thompson & Ferris, 1990). Regions with mafic and ultramafic bedrock, such as near Atlin, British Columbia, Canada, represent the best potential sources of feedstocks for mineral carbonation. The hydromagnesite playas near Atlin are a natural biogeochemical model for the carbonation of magnesium silicate minerals (Power et al., 2009). Field-based studies at Atlin and corroborating laboratory experiments demonstrate the ability of a microbial consortium dominated by filamentous cyanobacteria to induce the precipitation of carbonate minerals. Phototrophic microbes, such as cyanobacteria, have been proposed as a means for producing biodiesel and other value added products because of their efficiency as solar collectors and low requirement for valuable, cultivable land in comparison to crops (Dismukes et al., 2008). Carbonate precipitation and biomass production could be facilitated using specifically designed ponds to collect waters rich in dissolved cations (e.g., Mg2+ and Ca2+), which would allow for evapoconcentration and provide an appropriate environment for growth of cyanobacteria. Microbially mediated carbonate precipitation does not require large quantities of energy or chemicals needed for industrial systems that have been proposed for rapid carbon capture and storage via mineral carbonation (e.g., Lackner et al., 1995). Therefore, this biogeochemical approach may represent a readily

  13. Nanoparticle mediated micromotor motion

    Science.gov (United States)

    Liu, Mei; Liu, Limei; Gao, Wenlong; Su, Miaoda; Ge, Ya; Shi, Lili; Zhang, Hui; Dong, Bin; Li, Christopher Y.

    2015-03-01

    In this paper, we report the utilization of nanoparticles to mediate the motion of a polymer single crystal catalytic micromotor. Micromotors have been fabricated by directly self-assembling functional nanoparticles (platinum and iron oxide nanoparticles) onto one or both sides of two-dimensional polymer single crystals. We show that the moving velocity of these micromotors in fluids can be readily tuned by controlling the nanoparticles' surface wettability and catalytic activity. A 3 times velocity increase has been achieved for a hydrophobic micromotor as opposed to the hydrophilic ones. Furthermore, we demonstrate that the catalytic activity of platinum nanoparticles inside the micromotor can be enhanced by their synergetic interactions with iron oxide nanoparticles and an electric field. Both strategies lead to dramatically increased moving velocities, with the highest value reaching ~200 μm s-1. By decreasing the nanoparticles' surface wettability and increasing their catalytic activity, a maximum of a ~10-fold increase in the moving speed of the nanoparticle based micromotor can be achieved. Our results demonstrate the advantages of using nanoparticles in micromotor systems.In this paper, we report the utilization of nanoparticles to mediate the motion of a polymer single crystal catalytic micromotor. Micromotors have been fabricated by directly self-assembling functional nanoparticles (platinum and iron oxide nanoparticles) onto one or both sides of two-dimensional polymer single crystals. We show that the moving velocity of these micromotors in fluids can be readily tuned by controlling the nanoparticles' surface wettability and catalytic activity. A 3 times velocity increase has been achieved for a hydrophobic micromotor as opposed to the hydrophilic ones. Furthermore, we demonstrate that the catalytic activity of platinum nanoparticles inside the micromotor can be enhanced by their synergetic interactions with iron oxide nanoparticles and an electric

  14. Estimation of Causal Mediation Effects for a Dichotomous Outcome in Multiple-Mediator Models using the Mediation Formula

    OpenAIRE

    Wang, Wei; Nelson, Suchitra; Albert, Jeffrey M.

    2013-01-01

    Mediators are intermediate variables in the causal pathway between an exposure and an outcome. Mediation analysis investigates the extent to which exposure effects occur through these variables, thus revealing causal mechanisms. In this paper, we consider the estimation of the mediation effect when the outcome is binary and multiple mediators of different types exist. We give a precise definition of the total mediation effect as well as decomposed mediation effects through individual or sets ...

  15. Mediation of information and educational mediation: conceptual discussions

    Directory of Open Access Journals (Sweden)

    Helena Célia de Souza Sacerdote

    2016-04-01

    Full Text Available Introduction: This is systematization of theoretical and methodological contributions related to the concepts of mediation information and pedagogical mediation in the literature. Objective: To understand possible intersection of information science and Online Education with regard to these concepts to check that both can be considered as analogous in its essence and practice. Methodology: Literature review based on literature by consulting the scientific productions selected in search of SciELO.ORG databases and EBSCO Host, the portal of CAPES / MEC and Google Scholar. Results: The most cited concepts in information science and education were de Almeida Junior (2009 and Masetto (2013, respectively. Conclusion: It is observed that the concept of mediation can move interchangeably between both areas. This is because the evidence found in the productions of the last five years indicate that the concept of information of mediation seems to have found its bases in education (educational psychology.

  16. The mediatization of ethical consumption

    DEFF Research Database (Denmark)

    Eskjær, Mikkel Fugl

    2013-01-01

    Over the years, mediatization studies have investigated the influence of media in numerous sections of contemporary society. One area that has received limited attention is the mediatization of consumption, particularly issues concerning ethical consumption. This article presents a study of how...... mediatization is transforming modern consumption and contributing to the mainstreaming of ethical consumption. Based on a study of a Danish online eco-store, the article argues that modern ethical consumption increasingly depends on new media practices to present sustainable consumption as practical...

  17. Assay of mast cell mediators

    DEFF Research Database (Denmark)

    Rådinger, Madeleine; Jensen, Bettina M; Swindle, Emily

    2015-01-01

    Mediator release from activated mast cells is a major initiator of the symptomology associated with allergic disorders such as anaphylaxis and asthma. Thus, methods to monitor the generation and release of such mediators have widespread applicability in studies designed to understand the processes...... regulating mast cell activation and for the identification of therapeutic approaches to block mast cell-driven disease. In this chapter, we discuss approaches used for the determination of mast cell degranulation, lipid-derived inflammatory mediator production, and cytokine/chemokine gene expression as well...

  18. Doing statistical mediation and moderation

    CERN Document Server

    Jose, Paul E

    2013-01-01

    Written in a friendly, conversational style, this book offers a hands-on approach to statistical mediation and moderation for both beginning researchers and those familiar with modeling. Starting with a gentle review of regression-based analysis, Paul Jose covers basic mediation and moderation techniques before moving on to advanced topics in multilevel modeling, structural equation modeling, and hybrid combinations, such as moderated mediation. User-friendly features include numerous graphs and carefully worked-through examples; ""Helpful Suggestions"" about procedures and pitfalls; ""Knowled

  19. Estimation of causal mediation effects for a dichotomous outcome in multiple-mediator models using the mediation formula.

    Science.gov (United States)

    Wang, Wei; Nelson, Suchitra; Albert, Jeffrey M

    2013-10-30

    Mediators are intermediate variables in the causal pathway between an exposure and an outcome. Mediation analysis investigates the extent to which exposure effects occur through these variables, thus revealing causal mechanisms. In this paper, we consider the estimation of the mediation effect when the outcome is binary and multiple mediators of different types exist. We give a precise definition of the total mediation effect as well as decomposed mediation effects through individual or sets of mediators using the potential outcomes framework. We formulate a model of joint distribution (probit-normal) using continuous latent variables for any binary mediators to account for correlations among multiple mediators. A mediation formula approach is proposed to estimate the total mediation effect and decomposed mediation effects based on this parametric model. Estimation of mediation effects through individual or subsets of mediators requires an assumption involving the joint distribution of multiple counterfactuals. We conduct a simulation study that demonstrates low bias of mediation effect estimators for two-mediator models with various combinations of mediator types. The results also show that the power to detect a nonzero total mediation effect increases as the correlation coefficient between two mediators increases, whereas power for individual mediation effects reaches a maximum when the mediators are uncorrelated. We illustrate our approach by applying it to a retrospective cohort study of dental caries in adolescents with low and high socioeconomic status. Sensitivity analysis is performed to assess the robustness of conclusions regarding mediation effects when the assumption of no unmeasured mediator-outcome confounders is violated. Copyright © 2013 John Wiley & Sons, Ltd.

  20. Estimation of Causal Mediation Effects for a Dichotomous Outcome in Multiple-Mediator Models using the Mediation Formula

    Science.gov (United States)

    Nelson, Suchitra; Albert, Jeffrey M.

    2013-01-01

    Mediators are intermediate variables in the causal pathway between an exposure and an outcome. Mediation analysis investigates the extent to which exposure effects occur through these variables, thus revealing causal mechanisms. In this paper, we consider the estimation of the mediation effect when the outcome is binary and multiple mediators of different types exist. We give a precise definition of the total mediation effect as well as decomposed mediation effects through individual or sets of mediators using the potential outcomes framework. We formulate a model of joint distribution (probit-normal) using continuous latent variables for any binary mediators to account for correlations among multiple mediators. A mediation formula approach is proposed to estimate the total mediation effect and decomposed mediation effects based on this parametric model. Estimation of mediation effects through individual or subsets of mediators requires an assumption involving the joint distribution of multiple counterfactuals. We conduct a simulation study that demonstrates low bias of mediation effect estimators for two-mediator models with various combinations of mediator types. The results also show that the power to detect a non-zero total mediation effect increases as the correlation coefficient between two mediators increases, while power for individual mediation effects reaches a maximum when the mediators are uncorrelated. We illustrate our approach by applying it to a retrospective cohort study of dental caries in adolescents with low and high socioeconomic status. Sensitivity analysis is performed to assess the robustness of conclusions regarding mediation effects when the assumption of no unmeasured mediator-outcome confounders is violated. PMID:23650048

  1. Mediation analysis with multiple versions of the mediator

    OpenAIRE

    VanderWeele, Tyler J.

    2012-01-01

    The causal inference literature has provided definitions of direct and indirect effects based on counterfactuals that generalize the approach found in the social science literature. However, these definitions presuppose well defined hypothetical interventions on the mediator. In many settings there may be multiple ways to fix the mediator to a particular value and these different hypothetical interventions may have very different implications for the outcome of interest. In this paper we cons...

  2. Dimensional reduction in anomaly mediation

    International Nuclear Information System (INIS)

    Boyda, Ed; Murayama, Hitoshi; Pierce, Aaron

    2002-01-01

    We offer a guide to dimensional reduction in theories with anomaly-mediated supersymmetry breaking. Evanescent operators proportional to ε arise in the bare Lagrangian when it is reduced from d=4 to d=4-2ε dimensions. In the course of a detailed diagrammatic calculation, we show that inclusion of these operators is crucial. The evanescent operators conspire to drive the supersymmetry-breaking parameters along anomaly-mediation trajectories across heavy particle thresholds, guaranteeing the ultraviolet insensitivity

  3. 22 CFR 218.33 - Mediation.

    Science.gov (United States)

    2010-04-01

    ... 22 Foreign Relations 1 2010-04-01 2010-04-01 false Mediation. 218.33 Section 218.33 Foreign... § 218.33 Mediation. (a) Referral of complaints for mediation. The agency will refer to the Federal Mediation and Conciliation Service all complaints that: (1) fall within the jurisdiction of these...

  4. 15 CFR 923.54 - Mediation.

    Science.gov (United States)

    2010-01-01

    ... 15 Commerce and Foreign Trade 3 2010-01-01 2010-01-01 false Mediation. 923.54 Section 923.54... Mediation. (a) Section 307(h) of the Act provides for mediation of serious disagreement between any Federal... cases, mediation by the Secretary, with the assistance of the Executive Office of the President, may be...

  5. 10 CFR 4.333 - Mediation.

    Science.gov (United States)

    2010-01-01

    ... 10 Energy 1 2010-01-01 2010-01-01 false Mediation. 4.333 Section 4.333 Energy NUCLEAR REGULATORY... Investigation, Conciliation, and Enforcement Procedures § 4.333 Mediation. (a) Referral of complaints for mediation. NRC will refer to a mediation agency designated by the Secretary of the Department of Health and...

  6. 45 CFR 1156.16 - Mediation.

    Science.gov (United States)

    2010-10-01

    ... 45 Public Welfare 3 2010-10-01 2010-10-01 false Mediation. 1156.16 Section 1156.16 Public Welfare... Procedures § 1156.16 Mediation. (a) Referral of complaints for mediation. The Endowment will promptly refer all complaints to the agency designated by the Secretary of HHS to manage the mediation process that...

  7. 15 CFR 930.111 - OCRM mediation.

    Science.gov (United States)

    2010-01-01

    ... 15 Commerce and Foreign Trade 3 2010-01-01 2010-01-01 false OCRM mediation. 930.111 Section 930... FEDERAL CONSISTENCY WITH APPROVED COASTAL MANAGEMENT PROGRAMS Secretarial Mediation § 930.111 OCRM mediation. The availability of mediation does not preclude use by the parties of alternative means for...

  8. 14 CFR 1252.402 - Mediation.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 5 2010-01-01 2010-01-01 false Mediation. 1252.402 Section 1252.402... Procedures § 1252.402 Mediation. (a) Referral of complaints for mediation. NASA will refer to the Federal Mediation and Conciliation Service all complaints that: (1) Fall within the jurisdiction of the Act and...

  9. 10 CFR 1040.89-6 - Mediation.

    Science.gov (United States)

    2010-01-01

    ... 10 Energy 4 2010-01-01 2010-01-01 false Mediation. 1040.89-6 Section 1040.89-6 Energy DEPARTMENT... Enforcement Procedures § 1040.89-6 Mediation. (a) Referral of complaints for mediation. DOE will refer to the Federal Mediation and Conciliation Service, in accordance with 45 CFR 90.43(c)(3), all complaints that: (1...

  10. 34 CFR 110.32 - Mediation.

    Science.gov (United States)

    2010-07-01

    ... 34 Education 1 2010-07-01 2010-07-01 false Mediation. 110.32 Section 110.32 Education Regulations..., Conciliation, and Enforcement Procedures § 110.32 Mediation. (a) ED promptly refers to the Federal Mediation and Conciliation Service or to the mediation agency designated by the Secretary of Health and Human...

  11. 7 CFR 780.9 - Mediation.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 7 2010-01-01 2010-01-01 false Mediation. 780.9 Section 780.9 Agriculture Regulations... PROGRAMS APPEAL REGULATIONS § 780.9 Mediation. (a) Any request for mediation must be submitted after... once: (1) If resolution of an adverse decision is not achieved in mediation, a participant may exercise...

  12. 24 CFR 146.35 - Mediation.

    Science.gov (United States)

    2010-04-01

    ... 24 Housing and Urban Development 1 2010-04-01 2010-04-01 false Mediation. 146.35 Section 146.35... ASSISTANCE Investigation, Settlement, and Enforcement Procedures § 146.35 Mediation. (a) HUD shall refer to the Federal Mediation and Conciliation Service, a mediation agency designated by the Secretary of...

  13. 7 CFR 614.11 - Mediation.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 6 2010-01-01 2010-01-01 false Mediation. 614.11 Section 614.11 Agriculture... AGRICULTURE CONSERVATION OPERATIONS NRCS APPEAL PROCEDURES § 614.11 Mediation. (a) A participant who wishes to pursue mediation must file request for mediation under this part with the NRCS official designated in the...

  14. 15 CFR 20.12 - Mediation.

    Science.gov (United States)

    2010-01-01

    ... 15 Commerce and Foreign Trade 1 2010-01-01 2010-01-01 false Mediation. 20.12 Section 20.12... Procedures § 20.12 Mediation. (a) DOC will refer to a mediation service designated by the Secretary all... further processing. (b) Both the complainant and the recipient shall participate in the mediation process...

  15. 38 CFR 18.543 - Mediation.

    Science.gov (United States)

    2010-07-01

    ... 38 Pensions, Bonuses, and Veterans' Relief 2 2010-07-01 2010-07-01 false Mediation. 18.543 Section... Enforcement Procedures § 18.543 Mediation. (a) Referral of complaints for mediation. VA will refer to the Federal Mediation and Conciliation Service all complaints that: (1) Fall within the jurisdiction of the...

  16. Mediation in Schools: Tapping the Potential

    Science.gov (United States)

    Hendry, Richard

    2010-01-01

    This article explores the developing role of mediation as a conflict resolution process in schools. It gives an accepted definition and clarifies the purposes of mediation, outlining the range of contexts in and beyond schools in which mediation is already offered as a formal intervention. The typical process of mediation itself is described. The…

  17. Mediation and Counseling Services: A Viable Partnership

    Science.gov (United States)

    Hodges, Shannon

    2009-01-01

    Mediation has become common in many areas of society, including marital dissolution, community disputes, governmental agencies, and business and industry. Though higher education has been slower than society to adopt mediation services, campus mediation is becoming increasingly more common. This article explains why mediation is a viable…

  18. 45 CFR 91.43 - Mediation.

    Science.gov (United States)

    2010-10-01

    ... 45 Public Welfare 1 2010-10-01 2010-10-01 false Mediation. 91.43 Section 91.43 Public Welfare... Enforcement Procedures § 91.43 Mediation. (a) HHS will promptly refer to a mediation agency designated by the... mediation process to the extent necessary to reach an agreement or make an informed judgment that an...

  19. 43 CFR 17.332 - Mediation.

    Science.gov (United States)

    2010-10-01

    ... 43 Public Lands: Interior 1 2010-10-01 2010-10-01 false Mediation. 17.332 Section 17.332 Public..., and Enforcement Procedures § 17.332 Mediation. (a) Referral of complaints for mediation. DOI will... participate in the mediation process to the extent necessary to reach an agreement or make an informed...

  20. Neutrality in mediation: an ambiguous ethical value

    OpenAIRE

    Bailey, Paul

    2014-01-01

    Mediator neutrality would appear, by definition, to be a necessary and required ethical principle for all mediators to practice. But what is meant by neutrality in mediation? Is it practically possible to be completely neutral between parties in mediation while at the same time being fair to both of them? This paper attempts to answer these two questions.

  1. 7 CFR 900.108 - Mediator's report.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 8 2010-01-01 2010-01-01 false Mediator's report. 900.108 Section 900.108 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (Marketing Agreements... Mediator's report. The mediator, upon the completion of mediation proceedings, shall submit to the...

  2. Strongly coupled semidirect mediation of supersymmetry breaking

    International Nuclear Information System (INIS)

    Ibe, M.; Izawa, K.-I.; Nakai, Y.

    2009-01-01

    Strongly coupled semidirect gauge mediation models of supersymmetry breaking through massive mediators with standard-model charges are investigated by means of composite degrees of freedom. Sizable mediation is realized to generate the standard-model gaugino masses for a small mediator mass without breaking the standard-model symmetries.

  3. Gaugino-assisted anomaly mediation

    International Nuclear Information System (INIS)

    Kribs, Graham D.

    2001-01-01

    I present a model of supersymmetry breaking mediated through a small extra dimension. Standard model matter multiplets and a supersymmetry-breaking (or 'hidden') sector are confined to opposite four-dimensional boundaries while gauge multiplets live in the bulk. The hidden sector does not contain a singlet and the dominant contribution to gaugino masses is via anomaly-mediated supersymmetry breaking. Scalar masses get contributions from both anomaly mediation and a tiny hard breaking of supersymmetry by operators on the hidden-sector boundary. These operators contribute to scalar masses at one loop and in most of parameter space, their contribution dominates. Thus it is easy to make all squared scalar masses positive. As no additional fields or symmetries are required below the Planck scale, this is among the simplest working models of anomaly mediation. The gaugino spectrum is left untouched and the phenomenology of the model is roughly similar to anomaly mediated supersymmetry breaking with a universal scalar mass added. Finally, the main differences in the spectrum between this model and other approaches are identified. This talk is based on work [1] done in collaboration with David E. Kaplan

  4. Gaugino-Assisted Anomaly Mediation

    International Nuclear Information System (INIS)

    Kaplan, David Elazzar; Kribs, Graham D.

    2000-01-01

    We present a model of supersymmetry breaking mediated through a small extra dimension. Standard model matter multiplets and a supersymmetry-breaking (or ''hidden'') sector are confined to opposite four-dimensional boundaries while gauge multiplets live in the bulk. The hidden sector does not contain a singlet and the dominant contribution to gaugino masses is via anomaly-mediated supersymmetry breaking. Scalar masses get contributions from both anomaly mediation and a tiny hard breaking of supersymmetry by operators on the hidden-sector boundary. These operators contribute to scalar masses at one loop and in most of parameter space, their contribution dominates. Thus it is easy to make all squared scalar masses positive. As no additional fields or symmetries are required below the Planck scale, we consider this the simplest working model of anomaly mediation. The gaugino spectrum is left untouched and the phenomenology of the model is roughly similar to anomaly mediated supersymmetry breaking with a universal scalar mass added. We identify the main differences in the spectrum between this model and other approaches. We also discuss mechanisms for generating the μ term and constraints on additional bulk fields. (author)

  5. Role of mobile passenger lymphocytes in the rejection of renal and cardiac allografts in the rat. A passenger lymphocyte-mediated graft-versus-host reaction amplifies the host response

    International Nuclear Information System (INIS)

    van Vrieshilfgaarde, R.; Hermans, P.; Terpstra, J.L.; van Breda Viresman, P.J.

    1980-01-01

    It is demonstrated that passenger lymphocytes migrate out of rat renal allografts into host spleens in a radioresistant fashion. These mobile passenger lymphocytes within BN kidney and heart transplants are immunocompetent, since they elicit a graft-versus-host (GVH) reaction in the spleens of (LEW x BN)F2 hybrid hosts. The greater GVH reaction in (LEW x BN)F1 recipients of BN kidneys reflects the greater number of mobile passenger lymphocytes in the kidney when compared to the heart. The mobile passenger lymphocytes within BN renal allografts also cause a proliferative response in the spleens of the LEW hosts as well as an accelerated rejection of BN renal allografts when compared to BN cardiac allografts, for the differences between BN kidney and heart, both in terms of splenomegaly elicited in LEW as well as tempo of rejection, are abolished by total body x-irradiation of the donor with 900 rad. Results indicate that a mobile passenger lymphocyte mediated GVH reaction in the central lymphoid organs of the host augments the host response to allogenic kidneys and contributes materially to first-set renal allograft rejection; this GVH reaction on the other hand is not conspicuously present in LEW recipients of BN cardiac allografts and has therefore little effect on first-set cardiac allograft rejection

  6. Three tasks for mediatization research

    DEFF Research Database (Denmark)

    Ekstrøm, Mats; Fornäs, Johan; Jansson, André

    2016-01-01

    Based on the interdisciplinary experience of a Swedish research committee, this article discusses critical conceptual issues raised by the current debate on mediatization – a concept that holds great potential to constitute a space for synthesized understandings of media-related social transforma......Based on the interdisciplinary experience of a Swedish research committee, this article discusses critical conceptual issues raised by the current debate on mediatization – a concept that holds great potential to constitute a space for synthesized understandings of media-related social...... that mediatization researchers have sometimes formulated too grand claims as to mediatization’s status as a unitary approach, a meta-theory or a paradigm. Such claims have led to problematic confusions around the concept and should be abandoned in favour of a more open agenda. In line with such a call for openness...

  7. Gauge mediated mini-split

    Energy Technology Data Exchange (ETDEWEB)

    Cohen, Timothy [Institute of Theoretical Science, University of Oregon,Eugene, OR 97403 (United States); Craig, Nathaniel [Department of Physics, University of California,Santa Barbara, CA 93106 (United States); Knapen, Simon [Berkeley Center for Theoretical Physics,University of California, Berkeley, CA 94720 (United States); Theoretical Physics Group,Lawrence Berkeley National Laboratory, Berkeley, CA 94720 (United States)

    2016-03-15

    We propose a simple model of split supersymmetry from gauge mediation. This model features gauginos that are parametrically a loop factor lighter than scalars, accommodates a Higgs boson mass of 125 GeV, and incorporates a simple solution to the μ−b{sub μ} problem. The gaugino mass suppression can be understood as resulting from collective symmetry breaking. Imposing collider bounds on μ and requiring viable electroweak symmetry breaking implies small a-terms and small tan β — the stop mass ranges from 10{sup 5} to 10{sup 8} GeV. In contrast with models with anomaly + gravity mediation (which also predict a one-loop loop suppression for gaugino masses), our gauge mediated scenario predicts aligned squark masses and a gravitino LSP. Gluinos, electroweakinos and Higgsinos can be accessible at the LHC and/or future colliders for a wide region of the allowed parameter space.

  8. Mediation in Legal English Teaching

    Directory of Open Access Journals (Sweden)

    Chovancová Barbora

    2016-06-01

    Full Text Available Mediation is a language activity that has been unjustly neglected when preparing law students for their future professional careers. When trained in a professional context, students need to develop and improve complex communicative skills. These include not only the traditional language skills such as reading, writing, listening and speaking, but also more advanced skills such as summarizing, providing definitions, changing registers etc. All these are involved in the students’ acquisition of ‘soft skills’ that are particularly important for students of law since much of their future work involves interpersonal lawyer-client interaction. This article argues that mediation is a crucial (though previously underestimated skill and that law-oriented ESP instruction should provide training aimed at developing this skill. Showing a practical application of this approach, the paper demonstrates that mediation can be successfully integrated in the legal English syllabus and make the learning of legal English more effective.

  9. Radical-Mediated Enzymatic Polymerizations

    Science.gov (United States)

    Zavada, Scott R.; Battsengel, Tsatsral; Scott, Timothy F.

    2016-01-01

    Polymerization reactions are commonly effected by exposing monomer formulations to some initiation stimulus such as elevated temperature, light, or a chemical reactant. Increasingly, these polymerization reactions are mediated by enzymes―catalytic proteins―owing to their reaction efficiency under mild conditions as well as their environmental friendliness. The utilization of enzymes, particularly oxidases and peroxidases, for generating radicals via reduction-oxidation mechanisms is especially common for initiating radical-mediated polymerization reactions, including vinyl chain-growth polymerization, atom transfer radical polymerization, thiol–ene step-growth polymerization, and polymerization via oxidative coupling. While enzyme-mediated polymerization is useful for the production of materials intended for subsequent use, it is especially well-suited for in situ polymerizations, where the polymer is formed in the place where it will be utilized. Such polymerizations are especially useful for biomedical adhesives and for sensing applications. PMID:26848652

  10. Mediatization Theory and Digital Media

    DEFF Research Database (Denmark)

    Finnemann, Niels Ole

    2011-01-01

    In the 20th century, the term "media logic" was introduced to denote the influence of independent mass media on political systems and other institutions. In recent years the idea has been reworked and labelled "mediatization" to widen the framework by including new media and new areas of applicat......In the 20th century, the term "media logic" was introduced to denote the influence of independent mass media on political systems and other institutions. In recent years the idea has been reworked and labelled "mediatization" to widen the framework by including new media and new areas...

  11. Surfactant-Mediated Growth Revisited

    International Nuclear Information System (INIS)

    Meyerheim, H. L.; Sander, D.; Popescu, R.; Pan, W.; Kirschner, J.; Popa, I.

    2007-01-01

    The x-ray structure analysis of the oxygen-surfactant-mediated growth of Ni on Cu(001) identifies up to 0.15 monolayers of oxygen in subsurface octahedral sites. This questions the validity of the general view that surfactant oxygen floats on top of the growing Ni film. Rather, the surfactant action is ascribed to an oxygen-enriched zone extending over the two topmost layers. Surface stress measurements support this finding. Our results have important implications for the microscopic understanding of surfactant-mediated growth and the change of the magnetic anisotropy of the Ni films

  12. Playful mediation and virtual sociality

    Directory of Open Access Journals (Sweden)

    Sihem NAJJAR

    2010-01-01

    Full Text Available As a space of sociability, virtual games, especially online role playing games, allow us to capture the interest of the playfulness in social life, but they are means by which users are able to experiment their relationship to others. The virtual games as a mediation device, constitute a "pretext" to forge friendships, develop love relationships, improve language skills, discover other cultures, etc. Based on a sociological survey of Tunisian Internet users (both sexes fans of virtual games we try to show how playful mediation is producing a multifaceted virtual sociality inherent in our contemporary societies.

  13. Family education and television mediation

    Directory of Open Access Journals (Sweden)

    Paz CÁNOVAS LEONHARDT

    2010-07-01

    Full Text Available This article try to deal with the complex influence of television viewing in the process of socialization of children and adolescents, focusing our attention on the importance of the family as the mediator-educator agency of particular relevance. Once analyzed the basic theoretical assumptions, we deepened in reality under study by providing data about how the studied population lives television and what extent parental mediation influences and affects the process. The article concludes with some reflections and pedagogical suggestions which trying to help to the optimization of the educational reality.

  14. Dynamical Messengers for Gauge Mediation

    Energy Technology Data Exchange (ETDEWEB)

    Hook, Anson; Torroba, Gonzalo; /SLAC /Stanford U., Phys. Dept.

    2011-08-17

    We construct models of indirect gauge mediation where the dynamics responsible for breaking supersymmetry simultaneously generates a weakly coupled subsector of messengers. This provides a microscopic realization of messenger gauge mediation where the messenger and hidden sector fields are unified into a single sector. The UV theory is SQCD with massless and massive quarks plus singlets, and at low energies it flows to a weakly coupled quiver gauge theory. One node provides the primary source of supersymmetry breaking, which is then transmitted to the node giving rise to the messenger fields. These models break R-symmetry spontaneously, produce realistic gaugino and sfermion masses, and give a heavy gravitino.

  15. Mediating Multilingual Children's Language Resources

    Science.gov (United States)

    Potts, D.; Moran, M. J.

    2013-01-01

    The everyday reality of children's multilingualism is a significant resource for expanding students' perspectives on the world, but many questions remain regarding the negotiation of these resources in mainstream classrooms. Drawing on research from a long-term Canadian study of multiliterate pedagogies, this paper explores mediation of home…

  16. Trilinear-augmented gaugino mediation

    DEFF Research Database (Denmark)

    Heisig, Jan; Kersten, Jörn; Murphy, Nick

    2017-01-01

    We consider a gaugino-mediated supersymmetry breaking scenario where in addition to the gauginos the Higgs fields couple directly to the field that breaks supersymmetry. This yields non-vanishing trilinear scalar couplings in general, which can lead to large mixing in the stop sector providing...

  17. Anomaly mediation in superstring theory

    Energy Technology Data Exchange (ETDEWEB)

    Conlon, Joseph P. [Rudolf Peierls Center for Theoretical Physics, Oxford (United Kingdom); Balliol College, Oxford (United Kingdom); Goodsell, Mark [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Palti, Eran [Centre de Physique Theoretique, Ecole Polytechnique, CNRS, Palaiseau (France)

    2010-08-15

    We study anomaly mediated supersymmetry breaking in type IIB string theory and use our results to test the supergravity formula for anomaly mediated gaugino masses. We compute 1-loop gaugino masses for models of D3-branes on orbifold singularities with 3-form fluxes by calculating the annulus correlator of 3-form flux and two gauginos in the zero momentum limit. Consistent with supergravity expectations we find both anomalous and running contributions to 1-loop gaugino masses. For background Neveu-Schwarz H-flux we find an exact match with the supergravity formula. For Ramond-Ramond flux there is an off-shell ambiguity that precludes a full matching. The anomaly mediated gaugino masses, while determined by the infrared spectrum, arise from an explicit sum over UV open string winding modes. We also calculate brane-to-brane tree-level gravity mediated gaugino masses and show that there are two contributions coming from the dilaton and from the twisted modes, which are suppressed by the full T{sup 6} volume and the untwisted T{sup 2} volume respectively. (orig.)

  18. Sonic mediations: body, sound, technology

    NARCIS (Netherlands)

    Birdsall, C.; Enns, A.

    2008-01-01

    Sonic Mediations: Body, Sound, Technology is a collection of original essays that represents an invaluable contribution to the burgeoning field of sound studies. While sound is often posited as having a bridging function, as a passive in-between, this volume invites readers to rethink the concept of

  19. Diselenolane-mediated cellular uptake.

    Science.gov (United States)

    Chuard, Nicolas; Poblador-Bahamonde, Amalia I; Zong, Lili; Bartolami, Eline; Hildebrandt, Jana; Weigand, Wolfgang; Sakai, Naomi; Matile, Stefan

    2018-02-21

    The emerging power of thiol-mediated uptake with strained disulfides called for a move from sulfur to selenium. We report that according to results with fluorescent model substrates, cellular uptake with 1,2-diselenolanes exceeds uptake with 1,2-dithiolanes and epidithiodiketopiperazines with regard to efficiency as well as intracellular localization. The diselenide analog of lipoic acid performs best. This 1,2-diselenolane delivers fluorophores efficiently to the cytosol of HeLa Kyoto cells, without detectable endosomal capture as with 1,2-dithiolanes or dominant escape into the nucleus as with epidithiodiketopiperazines. Diselenolane-mediated cytosolic delivery is non-toxic (MTT assay), sensitive to temperature but insensitive to inhibitors of endocytosis (chlorpromazine, methyl-β-cyclodextrin, wortmannin, cytochalasin B) and conventional thiol-mediated uptake (Ellman's reagent), and to serum. Selenophilicity, the extreme CSeSeC dihedral angle of 0° and the high but different acidity of primary and secondary selenols might all contribute to uptake. Thiol-exchange affinity chromatography is introduced as operational mimic of thiol-mediated uptake that provides, in combination with rate enhancement of DTT oxidation, direct experimental evidence for existence and nature of the involved selenosulfides.

  20. Mediated Encryption: Analysis and Design

    Directory of Open Access Journals (Sweden)

    I. Elashry1

    2015-01-01

    Full Text Available Boneh, Ding and Tsudik presented identity-based mediated RSA encryption and signature systems in which the users are not allowed to decrypt/sign messages without the authorisation of a security mediator.We show that ID-MRSA is not secure and we present a secure modified version of it which is as efficient as the original system. We also propose a generic mediated encryption that translates any identity based encryption to a mediated version of this IBE. It envelops an IBE encrypted message using a user’s identity into an IBE envelope using the identity of the SEM. We present two security models based on the role of the adversary whether it is a revoked user or a hacked SEM. We prove that GME is as secure as the SEM’s IBE against a revoked user and as secure as the user’s IBE against a hacked SEM. We also present two implementations of GME based on Boneh-Franklin FullIBE system which is a pairing-based system and Boneh, Gentry and Hamburg (BGH system which is pairing-free system.

  1. Crime fiction and mediatized religion

    DEFF Research Database (Denmark)

    Hansen, Kim Toft

    Scandinavian media where religion has become mediatized. Consumers of popular culture no longer endorse confidence in institutionalized religion, but that does not mean that people are losing faith: Faith only seems to adjust itself and tiptoe into popular media and popular fiction. Hence, this paper seeks...

  2. Mediation –Voluntary or Mandatory Procedure

    Directory of Open Access Journals (Sweden)

    Angelica ROSU

    2010-03-01

    Full Text Available Part of modifications brought through 370/2009 Act to the 192/2006 Law concerning mediation and structure of mediator profession have been interpreted as establishing a preliminary mediation procedure before intimating the courts of law, in civil and commercial matters. This interpretation is in excess of operative legal provisions. Although the law in modified form stipulates the compulsoriness of judicial authorities and other jurisdictional bodies to inform the parties about the possibility and the dvantages of using mediation procedure and the obligation to guide the parties to resort at mediation, this circumstances does not affect the mediation particular voluntary nature.

  3. Profession of mediator as the professional provider of the mediation process

    Directory of Open Access Journals (Sweden)

    Jernej Šoštar

    2017-03-01

    Full Text Available The civil mediation programme, which is a court-connected programme, established as a form of alternative dispute resolution, is increasingly gaining ground as a field with its own theoretical and practical knowledge, principles and basic rules. Mediation has already set up its own body of knowledge, based on studies, classification of cases and the analyses of the results. In this article, we examine whether in the context of the development of mediation in Slovenia we might already talk about the profession of the mediator, defined as a provider of the mediation process. We examine the court-connected civil mediation and mediators who mediate at the court-connected civil mediation, and define them theoretically. By interviewing the mediation experts and mediators we examine their opinions about mediators and the court mediation. We examine the legal basis for the court-connected mediation programmes in Slovenia as well as in the European Union. Proceeding from our findings we conclude that the legal regulation of the court mediation in Slovenia is well established, and that the mediators of the court-connected civil mediation programmes can be accepted as the professional providers of the mediation process.

  4. Ratio-of-Mediator-Probability Weighting for Causal Mediation Analysis in the Presence of Treatment-by-Mediator Interaction

    Science.gov (United States)

    Hong, Guanglei; Deutsch, Jonah; Hill, Heather D.

    2015-01-01

    Conventional methods for mediation analysis generate biased results when the mediator--outcome relationship depends on the treatment condition. This article shows how the ratio-of-mediator-probability weighting (RMPW) method can be used to decompose total effects into natural direct and indirect effects in the presence of treatment-by-mediator…

  5. Mediation Works: An Action Research Study Evaluating the Peer Mediation Program from the Eyes of Mediators and Faculty

    Science.gov (United States)

    Cook, Jacqueline Yvonne; Boes, Susan R.

    2013-01-01

    A literature review was conducted to understand how mediators and faculty view a Peer Mediation Program (PMP). The review identified four subgroups: mediators, teachers, administrators, and school counselors as well as their views on the success or lack of success of PMPs. The research also reflects how to best engage stakeholders in the mediation…

  6. Interdependence of laminin-mediated clustering of lipid rafts and the dystrophin complex in astrocytes.

    Science.gov (United States)

    Noël, Geoffroy; Tham, Daniel Kai Long; Moukhles, Hakima

    2009-07-17

    Astrocyte endfeet surrounding blood vessels are active domains involved in water and potassium ion transport crucial to the maintenance of water and potassium ion homeostasis in brain. A growing body of evidence points to a role for dystroglycan and its interaction with perivascular laminin in the targeting of the dystrophin complex and the water-permeable channel, aquaporin 4 (AQP4), at astrocyte endfeet. However, the mechanisms underlying such compartmentalization remain poorly understood. In the present study we found that AQP4 resided in Triton X-100-insoluble fraction, whereas dystroglycan was recovered in the soluble fraction in astrocytes. Cholesterol depletion resulted in the translocation of a pool of AQP4 to the soluble fraction indicating that its distribution is indeed associated with cholesterol-rich membrane domains. Upon laminin treatment AQP4 and the dystrophin complex, including dystroglycan, reorganized into laminin-associated clusters enriched for the lipid raft markers GM1 and flotillin-1 but not caveolin-1. Reduced diffusion rates of GM1 in the laminin-induced clusters were indicative of the reorganization of raft components in these domains. In addition, both cholesterol depletion and dystroglycan silencing reduced the number and area of laminin-induced clusters of GM1, AQP4, and dystroglycan. These findings demonstrate the interdependence between laminin binding to dystroglycan and GM1-containing lipid raft reorganization and provide novel insight into the dystrophin complex regulation of AQP4 polarization in astrocytes.

  7. Parameter space of general gauge mediation

    International Nuclear Information System (INIS)

    Rajaraman, Arvind; Shirman, Yuri; Smidt, Joseph; Yu, Felix

    2009-01-01

    We study a subspace of General Gauge Mediation (GGM) models which generalize models of gauge mediation. We find superpartner spectra that are markedly different from those of typical gauge and gaugino mediation scenarios. While typical gauge mediation predictions of either a neutralino or stau next-to-lightest supersymmetric particle (NLSP) are easily reproducible with the GGM parameters, chargino and sneutrino NLSPs are generic for many reasonable choices of GGM parameters.

  8. Mediation Analysis in Psychosomatic Medicine Research

    OpenAIRE

    Lockhart, Ginger; MacKinnon, David P.; Ohlrich, Vanessa

    2010-01-01

    This article presents an overview of statistical mediation analysis and its application to psychosomatic medicine research. The article begins with a description of the major approaches to mediation analysis and an evaluation of the strengths and limits of each. Emphasis is placed on longitudinal mediation models, and an application using latent growth modeling is presented. The article concludes with a description of recent developments in mediation analysis and suggestions for the use of me...

  9. Mediator oxidation systems in organic electrosynthesis

    International Nuclear Information System (INIS)

    Ogibin, Yurii N; Elinson, Michail N; Nikishin, Gennady I

    2009-01-01

    The data on the use of mediator oxidation systems activated by electric current (anodic or parallel anodic and cathodic) in organic electrosynthesis are considered and generalised. Electrochemical activation of these systems permits successful application of catalytic versions and easy scaling of mediator-promoted processes. Chemical and environmental advantages of electrochemical processes catalysed by mediator oxidation systems are demonstrated. Examples of the application of organic and inorganic mediators for the oxidation of various classes of organic compounds under conditions of electrolysis are given.

  10. LEGAL CULTURES AND MEDIATION. INTERACTIONS AND EVOLUTIONS

    Directory of Open Access Journals (Sweden)

    Claudiu Ramon D. BUTCULESCU

    2014-05-01

    Full Text Available Mediation, as an alternative dispute resolution method, is closely connected with the system of legal cultures. Mediation is an important link between legal culture and the judicial system. Mediation also acts as an interface between internal legal culture and external legal culture. This paper addresses the issues regarding the links and interactions between mediation and legal cultures, as well as the effects that arise from these interactions.

  11. Agrobacterium tumefaciens-Mediated Transformation

    DEFF Research Database (Denmark)

    Frandsen, Rasmus John Normand

    2015-01-01

    The use of Agrobacterium tumefaciens-mediated transformation for achieving genetic transformation of fungi has steadily increased over the last decade, and has proven to be almost universally applicable technique once suitable selection markers have been developed. In recent years the major...... technical advances has been made within the initial steps of the process, more specifically the efficient construction of plasmids for performing targeted genome modifications. This chapter provides a generic protocol for performing genetic transformation of ascomycetes via A. tumefaciens......-mediated transformation (AMT) and guidelines for optimizing the AMT process with new fungal species. The chapter also includes a highly efficient vector construction system based on Uracil Specific Excisions Reagent (USER) cloning and specific PCR generated building blocks, which can be combined ad hoc to create complex...

  12. Introduction: Mediating and Remediating Death

    DEFF Research Database (Denmark)

    Christensen, Dorthe Refslund; Sandvik, Kjetil

    2014-01-01

    In this second volume we explore how people, groups and institutions deal with death through processes of mediation (the presentation of something through media), remediation (the representation of one medium in another, see below) and mediatization (the process through which core elements...... of a social or cultural activity assume media form, see below). The volume presents a wide variety of ethnographies of death from Norway, Finland, Sweden, the US, Papua New Guinea, Bosnia and Hercegovina, Libya, Tibet, Uganda and Denmark as well as a number of online sites and social media material....... These are analyzed through a vast number of theoretical and analytical perspectives in order to investigate how very diverse practices surrounding death and dying - mourning and commemoration, ritualization, politicization, re-enactment, traditionalization, activism or documentarism: private or public, offline...

  13. Mediatization: a concept, multiple voices

    Directory of Open Access Journals (Sweden)

    Pedro Gilberto GOMES

    2016-12-01

    Full Text Available Mediatization has become increasingly a key concept, fundamental, essential to describe the present and the history of media and communicative change taking place. Thus, it became part of a whole, one can not see them as a separate sphere. In this perspective, the media coverage is used as a concept to describe the process of expansion of the different technical means and consider the interrelationships between the communicative change, means and sociocultural change. However, although many researchers use the concept of mediatization, each gives you the meaning that best suits your needs. Thus, the concept of media coverage is treated with multiple voices. This paper discusses this problem and present a preliminary pre-position on the matter.

  14. 41 CFR 101-8.717 - Mediation.

    Science.gov (United States)

    2010-07-01

    ... 41 Public Contracts and Property Management 2 2010-07-01 2010-07-01 true Mediation. 101-8.717... FINANCIAL ASSISTANCE 8.7-Discrimination Prohibited on the Basis of Age § 101-8.717 Mediation. (a) GSA promptly refers to the mediation agency designated by the Secretary, HHS, all sufficient complaints that...

  15. 34 CFR 303.419 - Mediation.

    Science.gov (United States)

    2010-07-01

    ... 34 Education 2 2010-07-01 2010-07-01 false Mediation. 303.419 Section 303.419 Education... DISABILITIES Procedural Safeguards Mediation and Due Process Procedures for Parents and Children § 303.419 Mediation. (a) General. Each State shall ensure that procedures are established and implemented to allow...

  16. 45 CFR 617.10 - Mediation.

    Science.gov (United States)

    2010-10-01

    ... 45 Public Welfare 3 2010-10-01 2010-10-01 false Mediation. 617.10 Section 617.10 Public Welfare... OF AGE IN PROGRAMS OR ACTIVITIES RECEIVING FEDERAL FINANCIAL ASSISTANCE FROM NSF § 617.10 Mediation. (a) NSF will refer to the Federal Mediation and Conciliation Service all complaints that fall within...

  17. 34 CFR 300.506 - Mediation.

    Science.gov (United States)

    2010-07-01

    ... 34 Education 2 2010-07-01 2010-07-01 false Mediation. 300.506 Section 300.506 Education... DISABILITIES Procedural Safeguards Due Process Procedures for Parents and Children § 300.506 Mediation. (a... due process complaint, to resolve disputes through a mediation process. (b) Requirements. The...

  18. Single-Level and Multilevel Mediation Analysis

    Science.gov (United States)

    Tofighi, Davood; Thoemmes, Felix

    2014-01-01

    Mediation analysis is a statistical approach used to examine how the effect of an independent variable on an outcome is transmitted through an intervening variable (mediator). In this article, we provide a gentle introduction to single-level and multilevel mediation analyses. Using single-level data, we demonstrate an application of structural…

  19. 7 CFR 900.109 - Mediation agreement.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 8 2010-01-01 2010-01-01 false Mediation agreement. 900.109 Section 900.109 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (Marketing... Mediation agreement. An agreement arrived at by mediation shall not become effective until approved by the...

  20. The Merits of Using Longitudinal Mediation

    Science.gov (United States)

    Jose, Paul E.

    2016-01-01

    Many of the mediation analyses reported in the literature are based on concurrent or single-occasion data sets. The 2 overarching themes of the present article are: Results of concurrent mediations are inherently ambiguous, and researchers would be wise to conduct mediations on longitudinal data sets instead. An example included here demonstrates…