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Sample records for cellular senescence induced

  1. Resveratrol Attenuates Copper-Induced Senescence by Improving Cellular Proteostasis

    Science.gov (United States)

    2017-01-01

    Copper sulfate-induced premature senescence (CuSO4-SIPS) consistently mimetized molecular mechanisms of replicative senescence, particularly at the endoplasmic reticulum proteostasis level. In fact, disruption of protein homeostasis has been associated to age-related cell/tissue dysfunction and human disorders susceptibility. Resveratrol is a polyphenolic compound with proved antiaging properties under particular conditions. In this setting, we aimed to evaluate resveratrol ability to attenuate cellular senescence induction and to unravel related molecular mechanisms. Using CuSO4-SIPS WI-38 fibroblasts, resveratrol is shown to attenuate typical senescence alterations on cell morphology, senescence-associated beta-galactosidase activity, and cell proliferation. The mechanisms implicated in this antisenescence effect seem to be independent of senescence-associated genes and proteins regulation but are reliant on cellular proteostasis improvement. In fact, resveratrol supplementation restores copper-induced increased protein content, attenuates BiP level, and reduces carbonylated and polyubiquitinated proteins by autophagy induction. Our data provide compelling evidence for the beneficial effects of resveratrol by mitigating CuSO4-SIPS stressful consequences by the modulation of protein quality control systems. These findings highlight the importance of a balanced cellular proteostasis and add further knowledge on molecular mechanisms mediating resveratrol antisenescence effects. Moreover, they contribute to identifying specific molecular targets whose modulation will prevent age-associated cell dysfunction and improve human healthspan. PMID:28280523

  2. Resveratrol Attenuates Copper-Induced Senescence by Improving Cellular Proteostasis

    Directory of Open Access Journals (Sweden)

    Liliana Matos

    2017-01-01

    Full Text Available Copper sulfate-induced premature senescence (CuSO4-SIPS consistently mimetized molecular mechanisms of replicative senescence, particularly at the endoplasmic reticulum proteostasis level. In fact, disruption of protein homeostasis has been associated to age-related cell/tissue dysfunction and human disorders susceptibility. Resveratrol is a polyphenolic compound with proved antiaging properties under particular conditions. In this setting, we aimed to evaluate resveratrol ability to attenuate cellular senescence induction and to unravel related molecular mechanisms. Using CuSO4-SIPS WI-38 fibroblasts, resveratrol is shown to attenuate typical senescence alterations on cell morphology, senescence-associated beta-galactosidase activity, and cell proliferation. The mechanisms implicated in this antisenescence effect seem to be independent of senescence-associated genes and proteins regulation but are reliant on cellular proteostasis improvement. In fact, resveratrol supplementation restores copper-induced increased protein content, attenuates BiP level, and reduces carbonylated and polyubiquitinated proteins by autophagy induction. Our data provide compelling evidence for the beneficial effects of resveratrol by mitigating CuSO4-SIPS stressful consequences by the modulation of protein quality control systems. These findings highlight the importance of a balanced cellular proteostasis and add further knowledge on molecular mechanisms mediating resveratrol antisenescence effects. Moreover, they contribute to identifying specific molecular targets whose modulation will prevent age-associated cell dysfunction and improve human healthspan.

  3. [Senescence and cellular immortality].

    Science.gov (United States)

    Trentesaux, C; Riou, J-F

    2010-11-01

    Senescence was originally described from the observation of the limited ability of normal cells to grow in culture, and may be generated by telomere erosion, accumulation of DNA damages, oxidative stress and modulation of oncogenes or tumor suppressor genes. Senescence corresponds to a cellular response aiming to control tumor progression by limiting cell proliferation and thus constitutes an anticancer barrier. Senescence is observed in pre-malignant tumor stages and disappears from malignant tumors. Agents used in standard chemotherapy also have the potential to induce senescence, which may partly explain their therapeutic activities. It is possible to restore senescence in tumors using targeted therapies that triggers telomere dysfunction or reactivates suppressor genes functions, which are essential for the onset of senescence.

  4. Exercise Prevents Diet-Induced Cellular Senescence in Adipose Tissue

    NARCIS (Netherlands)

    Schafer, M.J.; White, T.A.; Evans, G.; Tonne, J.M.; Verzosa, G.C.; Stout, M.B.; Mazula, D.L.; Palmer, A.K.; Baker, D.J.; Jensen, M.D.; Torbenson, M.S.; Miller, J.D.; Ikeda, Y.; Tchkonia, T.; Deursen, J.M.A. van; Kirkland, J.L.; LeBrasseur, N.K.

    2016-01-01

    Considerable evidence implicates cellular senescence in the biology of aging and chronic disease. Diet and exercise are determinants of healthy aging; however, the extent to which they affect the behavior and accretion of senescent cells within distinct tissues is not clear. Here we tested the

  5. A small molecule inhibitor of PAI-1 protects against doxorubicin-induced cellular senescence.

    Science.gov (United States)

    Ghosh, Asish K; Rai, Rahul; Park, Kitae E; Eren, Mesut; Miyata, Toshio; Wilsbacher, Lisa D; Vaughan, Douglas E

    2016-11-08

    Doxorubicin, an anthracycline antibiotic, is a commonly used anticancer drug. In spite of its widespread usage, its therapeutic effect is limited by its cardiotoxicity. On the cellular level, Doxorubicin-induced cardiotoxicity manifests as stress induced premature senescence. Previously, we demonstrated that plasminogen activator inhibitor-1 (PAI-1), a potent inhibitor of serine proteases, is an important biomarker and regulator of cellular senescence and aging. Here, we tested the hypothesis that pharmacological inhibition of cellular PAI-1 protects against stress- and aging-induced cellular senescence and delineated the molecular basis of protective action of PAI-1 inhibition. Results show that TM5441, a potent small molecule inhibitor of PAI-1, effectively prevents Doxorubicin-induced senescence in cardiomyocytes, fibroblasts and endothelial cells. TM5441 exerts its inhibitory effect on Doxorubicin-induced cellular senescence by decreasing reactive oxygen species generation, induction of antioxidants like catalase and suppression of stress-induced senescence cadre p53, p21, p16, PAI-1 and IGFBP3. Importantly, TM5441 also reduces replicative senescence of fibroblasts. Together these results for the first time demonstrate the efficacy of PAI-1 inhibitor in prevention of Doxorubicin-induced and replicative senescence in normal cells. Thus PAI-1 inhibitor may form an important adjuvant component of chemotherapy regimens, limiting not only Doxorubicin-induced cardiac senescence but also ameliorating the prothrombotic profile.

  6. Attenuation of Replication Stress–Induced Premature Cellular Senescence to Assess Anti-Aging Modalities

    OpenAIRE

    Zhao, Hong; Darzynkiewicz, Zbigniew

    2014-01-01

    Described is an in vitro model of premature senescence in pulmonary adenocarcinoma A549 cells induced by persistent DNA replication stress in response to treatment with the DNA damaging drug mitoxantrone (Mxt). The degree of cellular senescence, based on characteristic changes in cell morphology, is measured by laser scanning cytometry. Specifically, the flattening of cells grown on slides (considered the hallmark of cellular senescence) is measured as the decline in local intensity of DNA-as...

  7. PTTG1 attenuates drug-induced cellular senescence.

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    Yunguang Tong

    Full Text Available As PTTG1 (pituitary tumor transforming gene abundance correlates with adverse outcomes in cancer treatment, we determined mechanisms underlying this observation by assessing the role of PTTG1 in regulating cell response to anti-neoplastic drugs. HCT116 cells devoid of PTTG1 (PTTG1(-/- exhibited enhanced drug sensitivity as assessed by measuring BrdU incorporation in vitro. Apoptosis, mitosis catastrophe or DNA damage were not detected, but features of senescence were observed using low doses of doxorubicin and TSA. The number of drug-induced PTTG1(-/- senescent cells increased ∼4 fold as compared to WT PTTG1-replete cells (p<0.001. p21, an important regulator of cell senescence, was induced ∼3 fold in HCT116 PTTG1(-/- cells upon doxorubicin or Trichostatin A treatment. Binding of Sp1, p53 and p300 to the p21 promoter was enhanced in PTTG1(-/- cells after treatment, suggesting transcriptional regulation of p21. p21 knock down abrogated the observed senescent effects of these drugs, indicating that PTTG1 likely suppresses p21 to regulate drug-induced senescence. PTTG1 also regulated SW620 colon cancer cells response to doxorubicin and TSA mediated by p21. Subcutaneously xenografted PTTG1(-/- HCT116 cells developed smaller tumors and exhibited enhanced responses to doxorubicin. PTTG1(-/- tumor tissue derived from excised tumors exhibited increased doxorubicin-induced senescence. As senescence is a determinant of cell responses to anti-neoplastic treatments, these findings suggest PTTG1 as a tumor cell marker to predict anti-neoplastic treatment outcomes.

  8. Markers of cellular senescence. Telomere shortening as a marker of cellular senescence.

    Science.gov (United States)

    Bernadotte, Alexandra; Mikhelson, Victor M; Spivak, Irina M

    2016-01-01

    The cellular senescence definition comes to the fact of cells irreversible proliferation disability. Besides the cell cycle arrest, senescent cells go through some morphological, biochemical, and functional changes which are the signs of cellular senescence. The senescent cells (including replicative senescence and stress-induced premature senescence) of all the tissues look alike. They are metabolically active and possess the set of characteristics in vitro and in vivo, which are known as biomarkers of aging and cellular senescence. Among biomarkers of cellular senescence telomere shortening is a rather elegant frequently used biomarker. Validity of telomere shortening as a marker for cellular senescence is based on theoretical and experimental data.

  9. Both Complexity and Location of DNA Damage Contribute to Cellular Senescence Induced by Ionizing Radiation.

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    Xurui Zhang

    Full Text Available Persistent DNA damage is considered as a main cause of cellular senescence induced by ionizing radiation. However, the molecular bases of the DNA damage and their contribution to cellular senescence are not completely clear. In this study, we found that both heavy ions and X-rays induced senescence in human uveal melanoma 92-1 cells. By measuring senescence associated-β-galactosidase and cell proliferation, we identified that heavy ions were more effective at inducing senescence than X-rays. We observed less efficient repair when DNA damage was induced by heavy ions compared with X-rays and most of the irreparable damage was complex of single strand breaks and double strand breaks, while DNA damage induced by X-rays was mostly repaired in 24 hours and the remained damage was preferentially associated with telomeric DNA. Our results suggest that DNA damage induced by heavy ion is often complex and difficult to repair, thus presents as persistent DNA damage and pushes the cell into senescence. In contrast, persistent DNA damage induced by X-rays is preferentially associated with telomeric DNA and the telomere-favored persistent DNA damage contributes to X-rays induced cellular senescence. These findings provide new insight into the understanding of high relative biological effectiveness of heavy ions relevant to cancer therapy and space radiation research.

  10. Glucose Oxidase Induces Cellular Senescence in Immortal Renal Cells through ILK by Downregulating Klotho Gene Expression

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    Nuria Troyano-Suárez

    2015-01-01

    Full Text Available Cellular senescence can be prematurely induced by oxidative stress involved in aging. In this work, we were searching for novel intermediaries in oxidative stress-induced senescence, focusing our interest on integrin-linked kinase (ILK, a scaffold protein at cell-extracellular matrix (ECM adhesion sites, and on the Klotho gene. Cultured renal cells were treated with glucose oxidase (GOx for long time periods. GOx induced senescence, increasing senescence associated β-galactosidase activity and the expression of p16. In parallel, GOx increased ILK protein expression and activity. Ectopic overexpression of ILK in cells increased p16 expression, even in the absence of GOx, whereas downregulation of ILK inhibited the increase in p16 due to oxidative stress. Additionally, GOx reduced Klotho gene expression and cells overexpressing Klotho protein did not undergo senescence after GOx addition. We demonstrated a direct link between ILK and Klotho since silencing ILK expression in cells and mice increases Klotho expression and reduces p53 and p16 expression in renal cortex. In conclusion, oxidative stress induces cellular senescence in kidney cells by increasing ILK protein expression and activity, which in turn reduces Klotho expression. We hereby present ILK as a novel downregulator of Klotho gene expression.

  11. Attenuation of Replication Stress–Induced Premature Cellular Senescence to Assess Anti-Aging Modalities

    Science.gov (United States)

    Zhao, Hong; Darzynkiewicz, Zbigniew

    2014-01-01

    Described is an in vitro model of premature senescence in pulmonary adenocarcinoma A549 cells induced by persistent DNA replication stress in response to treatment with the DNA damaging drug mitoxantrone (Mxt). The degree of cellular senescence, based on characteristic changes in cell morphology, is measured by laser scanning cytometry. Specifically, the flattening of cells grown on slides (considered the hallmark of cellular senescence) is measured as the decline in local intensity of DNA-associated DAPI fluorescence (represented by maximal pixels). This change is paralleled by an increase in nuclear area. Thus, the ratio of mean intensity of maximal pixels to nuclear area provides a very sensitive morphometric biomarker for the degree of senescence. This analysis is combined with immunocytochemical detection of senescence markers, such as overexpression of cyclin kinase inhibitors (e.g., p21WAF1) and phosphorylation of ribosomal protein S6 (rpS6), a key marker associated with aging/senescence that is detected using a phospho-specific antibody. These biomarker indices are presented in quantitative terms defined as a senescence index (SI), which is the fraction of the marker in test cultures relative to the same marker in exponentially growing control cultures. This system can be used to evaluate the anti-aging potential of test agents by assessing attenuation of maximal senescence. As an example, the inclusion of berberine, a natural alkaloid with reported anti-aging properties and a long history of use in traditional Chinese medicine, is shown to markedly attenuate the Mxt-induced SI and phosphorylation of rpS6. The multivariate analysis of senescence markers by laser scanning cytometry offers a promising tool to explore the potential anti-aging properties of a variety agents. PMID:24984966

  12. Attenuation of replication stress-induced premature cellular senescence to assess anti-aging modalities.

    Science.gov (United States)

    Zhao, Hong; Darzynkiewicz, Zbigniew

    2014-01-01

    Described is an in vitro model of premature senescence in pulmonary adenocarcinoma A549 cells induced by persistent DNA replication stress in response to treatment with the DNA damaging drug mitoxantrone (Mxt). The degree of cellular senescence, based on characteristic changes in cell morphology, is measured by laser scanning cytometry. Specifically, the flattening of cells grown on slides (considered the hallmark of cellular senescence) is measured as the decline in local intensity of DNA-associated DAPI fluorescence (represented by maximal pixels). This change is paralleled by an increase in nuclear area. Thus, the ratio of mean intensity of maximal pixels to nuclear area provides a very sensitive morphometric biomarker for the degree of senescence. This analysis is combined with immunocytochemical detection of senescence markers, such as overexpression of cyclin kinase inhibitors (e.g., p21(WAF1) ) and phosphorylation of ribosomal protein S6 (rpS6), a key marker associated with aging/senescence that is detected using a phospho-specific antibody. These biomarker indices are presented in quantitative terms defined as a senescence index (SI), which is the fraction of the marker in test cultures relative to the same marker in exponentially growing control cultures. This system can be used to evaluate the anti-aging potential of test agents by assessing attenuation of maximal senescence. As an example, the inclusion of berberine, a natural alkaloid with reported anti-aging properties and a long history of use in traditional Chinese medicine, is shown to markedly attenuate the Mxt-induced SI and phosphorylation of rpS6. The multivariate analysis of senescence markers by laser scanning cytometry offers a promising tool to explore the potential anti-aging properties of a variety agents.

  13. Ionizing Radiation Induces Cellular Senescence of Articular Chondrocytes via Negative Regulation of SIRT1 by p38 Kinase

    Energy Technology Data Exchange (ETDEWEB)

    Hong, Eun Hee; Hwang, Sang Gu [Korea Institute of Radiological and Medical Sciences, Seoul (Korea, Republic of)

    2009-05-15

    Senescent cells exhibit irreversible growth arrest, large flat morphology, and up-regulated senescence-associated {beta}-galactosidase activity at pH 6.0. Several conditions, including oncogenic stress, oxidative stress, and DNA damage are associated with cellular senescence. Massive acute DNA double-strand breaks occurring as a result of mechanical and chemical stress can be repaired, but some DNA damage persists, eventually triggering premature senescence. Since ionizing radiation directly induces DBS, it is possible that cellular senescence is activated under these conditions. The biological events in chondrocytes following irradiation are poorly understood, and limited information is available on the molecular signal transduction mechanisms of cellular senescence at present. In this study, we identify SIRT1 as a target molecule of p38 kinase and demonstrate that the interactions between p38 kinase and SIRT1 protein play an important role in the regulation of cellular senescence in response to IR.

  14. CREG1 enhances p16(INK4a) -induced cellular senescence.

    Science.gov (United States)

    Moolmuang, Benchamart; Tainsky, Michael A

    2011-02-01

    Cellular senescence is an irreversible growth arrest that is activated in normal cells upon shortening of telomere and other cellular stresses. Bypassing cellular senescence is a necessary step for cells to become immortal during oncogenic transformation. During the spontaneous immortalization of Li-Fraumeni Syndrome (LFS) fibroblasts, we found that CREG1 (Cellular Repressor of E1A-stimulated Genes 1) expression was decreased during immortalization and increased in senescence. Moreover, we found that repression of CREG1 expression occurs via an epigenetic mechanism, promoter DNA methylation. Ectopic expression of CREG1 in the immortal LFS cell lines decreases cell proliferation but does not directly induce senescence. We confirmed this in osteosarcoma and fibrosarcoma cancer cell lines, cancers commonly seen in Li-Fraumeni Syndrome. In addition, we found that p16 (INK4a) is also downregulated in immortal cells and that coexpression of CREG1 and p16 (INK4a) , an inhibitor of CDK4/6 and Rb phosphorylation, has a greater effect than either CREG1 and p16 (INK4a) alone to reduce cell growth, induce cell cycle arrest and cellular senescence in immortal LFS fibroblasts, osteosarcoma and fibrosarcoma cell lines. Moreover, cooperation of CREG1 and p16 (INK4a) inhibits the expression of cyclin A and cyclin B by inhibiting promoter activity thereby decreasing mRNA and protein levels; these proteins are required for S-phase entry and G2/M transition. In conclusion, this is the first evidence to demonstrate that CREG1 enhances p16 (INK4a) -induced senescence by transcriptional repression of cell cycle-regulated genes.

  15. Phenylbutyric acid induces the cellular senescence through an Akt/p21{sup WAF1} signaling pathway

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    Kim, Hag Dong [Laboratory of Biochemistry, School of Life Sciences and Biotechnology, and BioInstitute, Korea University, Seoul 136-701 (Korea, Republic of); Jang, Chang-Young [Research Center for Cell Fate Control, College of Pharmacy, Sookmyung Women' s University, Seoul 140-742 (Korea, Republic of); Choe, Jeong Min [Laboratory of Biochemistry, School of Life Sciences and Biotechnology, and BioInstitute, Korea University, Seoul 136-701 (Korea, Republic of); Department of Biochemistry, Korea University College of Medicine, Seoul 136-705 (Korea, Republic of); Korean Institute of Molecular Medicine and Nutrition, Seoul 136-705 (Korea, Republic of); Sohn, Jeongwon, E-mail: biojs@korea.ac.kr [Department of Biochemistry, Korea University College of Medicine, Seoul 136-705 (Korea, Republic of); Korean Institute of Molecular Medicine and Nutrition, Seoul 136-705 (Korea, Republic of); Kim, Joon, E-mail: joonkim@korea.ac.kr [Laboratory of Biochemistry, School of Life Sciences and Biotechnology, and BioInstitute, Korea University, Seoul 136-701 (Korea, Republic of)

    2012-06-01

    Highlights: Black-Right-Pointing-Pointer Phenylbutyric acid induces cellular senescence. Black-Right-Pointing-Pointer Phenylbutyric acid activates Akt kinase. Black-Right-Pointing-Pointer The knockdown of PERK also can induce cellular senescence. Black-Right-Pointing-Pointer Akt/p21{sup WAF1} pathway activates in PERK knockdown induced cellular senescence. -- Abstract: It has been well known that three sentinel proteins - PERK, ATF6 and IRE1 - initiate the unfolded protein response (UPR) in the presence of misfolded or unfolded proteins in the ER. Recent studies have demonstrated that upregulation of UPR in cancer cells is required to survive and proliferate. Here, we showed that long exposure to 4-phenylbutyric acid (PBA), a chemical chaperone that can reduce retention of unfolded and misfolded proteins in ER, induced cellular senescence in cancer cells such as MCF7 and HT1080. In addition, we found that treatment with PBA activates Akt, which results in p21{sup WAF1} induction. Interestingly, the depletion of PERK but not ATF6 and IRE1 also induces cellular senescence, which was rescued by additional depletion of Akt. This suggests that Akt pathway is downstream of PERK in PBA induced cellular senescence. Taken together, these results show that PBA induces cellular senescence via activation of the Akt/p21{sup WAF1} pathway by PERK inhibition.

  16. Accelerated Telomere Shortening in Acromegaly; IGF-I Induces Telomere Shortening and Cellular Senescence

    Science.gov (United States)

    Matsumoto, Ryusaku; Fukuoka, Hidenori; Iguchi, Genzo; Odake, Yukiko; Yoshida, Kenichi; Bando, Hironori; Suda, Kentaro; Nishizawa, Hitoshi; Takahashi, Michiko; Yamada, Shozo; Ogawa, Wataru; Takahashi, Yutaka

    2015-01-01

    Objective Patients with acromegaly exhibit reduced life expectancy and increased prevalence of age-related diseases, such as diabetes, hypertension, and cardiovascular disease. However, the underlying mechanism has not been fully elucidated. Telomere shortening is reportedly associated with reduced life expectancy and increased prevalence of these age-related diseases. Methods We measured telomere length in patients with acromegaly using quantitative PCR method. The effect of GH and IGF-I on telomere length and cellular senescence was examined in human skin fibroblasts. Results Patients with acromegaly exhibited shorter telomere length than age-, sex-, smoking-, and diabetes-matched control patients with non-functioning pituitary adenoma (0.62 ± 0.23 vs. 0.75 ± 0.35, respectively, P = 0.047). In addition, telomere length in acromegaly was negatively correlated with the disease duration (R2 = 0.210, P = 0.003). In vitro analysis revealed that not GH but IGF-I induced telomere shortening in human skin fibroblasts. Furthermore, IGF-I-treated cells showed increased senescence-associated β-galactosidase activity and expression of p53 and p21 protein. IGF-I-treated cells reached the Hayflick limit earlier than GH- or vehicle-treated cells, indicating that IGF-I induces cellular senescence. Conclusion Shortened telomeres in acromegaly and cellular senescence induced by IGF-I can explain, in part, the underlying mechanisms by which acromegaly exhibits an increased morbidity and mortality in association with the excess secretion of IGF-I. PMID:26448623

  17. All-trans retinoic acid induces cellular senescence via upregulation of p16, p21, and p27.

    Science.gov (United States)

    Park, Sun-Hye; Lim, Joo Song; Jang, Kyung Lib

    2011-11-28

    We here present a new anti-tumor mechanism of all-trans retinoic acid (ATRA). ATRA induced several biomarkers of cellular senescence including irreversible G1 arrest, morphological changes, senescence-associated β-galactosidase, and heterochromatin foci in HepG2 cells. ATRA also upregulated levels of p16, p21, and p27 which lead to activation of Rb and subsequent inactivation of E2F1. These effects were abolished by the RNA interference-mediated silencing of p16, p21, and p27. Moreover, ATRA failed to induce cellular senescence in Huh7 and HCT116, in which p16, p21, and p27 were not upregulated by ATRA, confirming that ATRA induces cellular senescence via upregulation of p16, p21, and p27. Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.

  18. Resveratrol sequentially induces replication and oxidative stresses to drive p53-CXCR2 mediated cellular senescence in cancer cells.

    Science.gov (United States)

    Li, Boxuan; Hou, Dong; Guo, Haiyang; Zhou, Haibin; Zhang, Shouji; Xu, Xiuhua; Liu, Qiao; Zhang, Xiyu; Zou, Yongxin; Gong, Yaoqin; Shao, Changshun

    2017-03-16

    Resveratrol (RSV) acts either as an antioxidant or a pro-oxidant depending on contexts. RSV-treated cancer cells may experience replication stress that can lead to cellular senescence or apoptosis. While both oxidative and replication stresses may mediate the anti-proliferation effect of RSV, to what extent each contributes to the impaired proliferation in response to RSV remains uncharacterized. We here report the study of the roles of replication and oxidative stresses in mediating cellular senescence in cancer cells treated with RSV. RSV induced S-phase arrest and cellular senescence in a dose-dependent manner in U2OS and A549 cancer cells as well as in normal human fibroblasts. We observed that nucleosides significantly alleviated RSV-induced replication stress and DNA damage response, and consequently attenuating cellular senescence. While the elevation of reactive oxygen species (ROS) also mediated the pro-senescent effect of RSV, it occurred after S-phase arrest. However, the induction of ROS by RSV was independent of S-phase arrest and actually reinforced the latter. We also demonstrated a critical role of the p53-CXCR2 axis in mediating RSV-induced senescence. Interestingly, CXCR2 also functioned as a barrier to apoptosis. Together, our results provided more insights into the biology of RSV-induced stress and its cellular consequences.

  19. Mitochondrial dysfunction induced by frataxin deficiency is associated with cellular senescence and abnormal calcium metabolism

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    Arantxa eBolinches-Amorós

    2014-05-01

    Full Text Available Friedreich ataxia is considered a neurodegenerative disorder involving both the peripheral and central nervous systems. Dorsal root ganglia (DRG are the major target tissue structures. This neuropathy is caused by mutations in the FXN gene that encodes frataxin. Here, we investigated the mitochondrial and cell consequences of frataxin depletion in a cellular model based on frataxin silencing in SH-SY5Y human neuroblastoma cells, a cell line that has been used widely as in vitro models for studies on neurological diseases. We showed that the reduction of frataxin induced mitochondrial dysfunction due to a bioenergetic deficit and abnormal Ca2+ homeostasis in the mitochondria that were associated with oxidative and endoplasmic reticulum stresses. The depletion of frataxin did not cause cell death but increased autophagy, which may have a cytoprotective effect against cellular insults such as oxidative stress. Frataxin silencing provoked slow cell growth associated with cellular senescence, as demonstrated by increased SA-βgal activity and cell cycle arrest at the G1 phase. We postulate that cellular senescence might be related to a hypoplastic defect in the DRG during neurodevelopment, as suggested by necropsy studies.

  20. Resveratrol induces cellular senescence with attenuated mono-ubiquitination of histone H2B in glioma cells

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    Gao, Zhen; Xu, Michael S.; Barnett, Tamara L. [Nevada Cancer Institute, Las Vegas, NV 89135 (United States); Xu, C. Wilson, E-mail: wxu@nvcancer.org [Nevada Cancer Institute, Las Vegas, NV 89135 (United States)

    2011-04-08

    Research highlights: {yields} Resveratrol induces cellular senescence in glioma cell. {yields} Resveratrol inhibits mono-ubiquitination of histone H2B at K120. {yields} Depletion of RNF20, phenocopies the inhibitory effects of resveratrol. {yields} Mono-ubiquitination of histone H2B at K120 is a novel target of resveratrol. {yields} RNF20 inhibits cellular senescence in proliferating glioma cells. -- Abstract: Resveratrol (3,4',5-trihydroxy-trans-stilbene), a polyphenol naturally occurring in grapes and other plants, has cancer chemo-preventive effects and therapeutic potential. Although resveratrol modulates multiple pathways in tumor cells, how resveratrol or its affected pathways converge on chromatin to mediate its effects is not known. Using glioma cells as a model, we showed here that resveratrol inhibited cell proliferation and induced cellular hypertrophy by transforming spindle-shaped cells to enlarged, irregular and flatten-shaped ones. We further showed that resveratrol-induced hypertrophic cells expressed senescence-associated-{beta}-galactosidase, suggesting that resveratrol-induced cellular senescence in glioma cells. Consistent with these observations, we demonstrated that resveratrol inhibited clonogenic efficiencies in vitro and tumor growth in a xenograft model. Furthermore, we found that acute treatment of resveratrol inhibited mono-ubiquitination of histone H2B at K120 (uH2B) in breast, prostate, pancreatic, lung, brain tumor cells as well as primary human cells. Chronic treatment with low doses of resveratrol also inhibited uH2B in the resveratrol-induced senescent glioma cells. Moreover, we showed that depletion of RNF20, a ubiquitin ligase of histone H2B, inhibited uH2B and induced cellular senescence in glioma cells in vitro, thereby recapitulated the effects of resveratrol. Taken together, our results suggest that uH2B is a novel direct or indirect chromatin target of resveratrol and RNF20 plays an important role in inhibiting cellular

  1. Acute dyskerin depletion triggers cellular senescence and renders osteosarcoma cells resistant to genotoxic stress-induced apoptosis

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    Lin, Ping; Mobasher, Maral E.; Alawi, Faizan, E-mail: falawi@upenn.edu

    2014-04-18

    Highlights: • Dyskerin depletion triggers cellular senescence in U2OS osteosarcoma cells. • Dyskerin-depleted cells are resistant to apoptosis induced by genotoxic stress. • Chromatin relaxation sensitizes dyskerin-depleted cells to apoptosis. - Abstract: Dyskerin is a conserved, nucleolar RNA-binding protein implicated in an increasing array of fundamental cellular processes. Germline mutation in the dyskerin gene (DKC1) is the cause of X-linked dyskeratosis congenita (DC). Conversely, wild-type dyskerin is overexpressed in sporadic cancers, and high-levels may be associated with poor prognosis. It was previously reported that acute loss of dyskerin function via siRNA-mediated depletion slowed the proliferation of transformed cell lines. However, the mechanisms remained unclear. Using human U2OS osteosarcoma cells, we show that siRNA-mediated dyskerin depletion induced cellular senescence as evidenced by proliferative arrest, senescence-associated heterochromatinization and a senescence-associated molecular profile. Senescence can render cells resistant to apoptosis. Conversely, chromatin relaxation can reverse the repressive effects of senescence-associated heterochromatinization on apoptosis. To this end, genotoxic stress-induced apoptosis was suppressed in dyskerin-depleted cells. In contrast, agents that induce chromatin relaxation, including histone deacetylase inhibitors and the DNA intercalator chloroquine, sensitized dyskerin-depleted cells to apoptosis. Dyskerin is a core component of the telomerase complex and plays an important role in telomere homeostasis. Defective telomere maintenance resulting in premature senescence is thought to primarily underlie the pathogenesis of X-linked DC. Since U2OS cells are telomerase-negative, this leads us to conclude that loss of dyskerin function can also induce cellular senescence via mechanisms independent of telomere shortening.

  2. YAP/TEAD-mediated transcription controls cellular senescence

    National Research Council Canada - National Science Library

    Xie, Qi; Chen, Jing; Feng, Han; Peng, Shengyi; Adams, Ursula; Bai, Yujie; Huang, Li; Li, Ji; Huang, Junjian; Meng, Songshu; Yuan, Zengqiang

    2013-01-01

    .... Silencing of YAP inhibits cell proliferation and induces premature senescence. In additional experiments, we observe that cellular senescence induced by YAP deficiency is TEAD- and Rb/p16/p53-dependent...

  3. SIRT6 Depletion Suppresses Tumor Growth by Promoting Cellular Senescence Induced by DNA Damage in HCC

    Science.gov (United States)

    Lee, Namgyu; Ryu, Hye Guk; Kwon, Jung-Hee; Kim, Dae-Kyum; Kim, Sae Rom; Wang, Hee Jung; Kim, Kyong-Tai; Choi, Kwan Yong

    2016-01-01

    The role of Sirtuin 6 (SIRT6) as a tumor suppressor or oncogene in liver cancer remains controversial. Thus, we identified the specific role of SIRT6 in the progression of hepatocellular carcinoma (HCC). SIRT6 expression was significantly higher in HCC cell lines and HCC tissues from 138 patients than in an immortalized hepatocyte cell line, THLE-2 and non-tumor tissues, respectively. SIRT6 knockdown by shRNA suppressed the growth of HCC cells and inhibited HCC tumor growth in vivo. In addition, SIRT6 silencing significantly prevented the growth of HCC cell lines by inducing cellular senescence in the p16/Rb- and p53/p21-pathway independent manners. Microarray analysis revealed that the expression of genes involved in nucleosome assembly was apparently altered in SIRT6-depleted Hep3B cells. SIRT6 knockdown promoted G2/M phase arrest and downregulation of genes encoding histone variants associated with nucleosome assembly, which could be attributed to DNA damage. Taken together, our findings suggest that SIRT6 acts as a tumor promoter by preventing DNA damage and cellular senescence, indicating that SIRT6 represents a potential therapeutic target for the treatment of HCC. PMID:27824900

  4. Changes and significance of SIRT3 expression in cellular senescence induced by high glucose

    Directory of Open Access Journals (Sweden)

    Bin ZHANG

    2011-09-01

    Full Text Available Objective To investigate the role of the silent information regulator 3(SIRT3 in the decrepitude process of human diploid fibroblasts(WI-38 induced by high glucose.Methods The WI-38 cells [population doublings(PDs,20-32] were cultured in media containing different concentrations of glucose as follows: low glucose(3.34mmol/L,LG,normal glucose(5.56mmol/L,NG,and high glucose(25mmol/L,HG.The protein expression levels of p21,p27,catalase,MnSOD,and SIRT3 were evaluated through Western blot.The double-label immunofluorescence assay was used to detect the location and expression of SIRT3,MnSOD,and senescence-associated heterochromatin foci(SAHF in the WI-38 cells.The ROS level was determined with fluorescent probe.Results The results from the Western blot showed that the protein expression of SIRT3,catalase,and MnSOD decreased significantly in the HG group compared with the LG and NG groups(P 0.05.SIRT3 and MnSOD were highly expressed in the cytoplasm.The ROS levels in the HG group were elevated compared with those in the LG and NG groups.Conclusion SIRT3 may play an important role in cellular senescence induced by high glucose in human diploid fibroblasts.

  5. Cellular Senescence: A Translational Perspective

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    James L. Kirkland

    2017-07-01

    Full Text Available Cellular senescence entails essentially irreversible replicative arrest, apoptosis resistance, and frequently acquisition of a pro-inflammatory, tissue-destructive senescence-associated secretory phenotype (SASP. Senescent cells accumulate in various tissues with aging and at sites of pathogenesis in many chronic diseases and conditions. The SASP can contribute to senescence-related inflammation, metabolic dysregulation, stem cell dysfunction, aging phenotypes, chronic diseases, geriatric syndromes, and loss of resilience. Delaying senescent cell accumulation or reducing senescent cell burden is associated with delay, prevention, or alleviation of multiple senescence-associated conditions. We used a hypothesis-driven approach to discover pro-survival Senescent Cell Anti-apoptotic Pathways (SCAPs and, based on these SCAPs, the first senolytic agents, drugs that cause senescent cells to become susceptible to their own pro-apoptotic microenvironment. Several senolytic agents, which appear to alleviate multiple senescence-related phenotypes in pre-clinical models, are beginning the process of being translated into clinical interventions that could be transformative.

  6. Relief of delayed oxidative stress by ascorbic acid can suppress radiation-induced cellular senescence in mammalian fibroblast cells.

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    Kobashigawa, Shinko; Kashino, Genro; Mori, Hiromu; Watanabe, Masami

    2015-03-01

    Ionizing radiation-induced cellular senescence is thought to be caused by nuclear DNA damage that cannot be repaired. However, here we found that radiation induces delayed increase of intracellular oxidative stress after irradiation. We investigated whether the relief of delayed oxidative stress by ascorbic acid would suppress the radiation-induced cellular senescence in Syrian golden hamster embryo (SHE) cells. We observed that the level of oxidative stress was drastically increased soon after irradiation, then declined to the level in non-irradiated cells, and increased again with a peak on day 3 after irradiation. We found that the inductions of cellular senescence after X-irradiation were reduced along with suppression of the delayed induction of oxidative stress by treatment with ascorbic acid, but not when oxidative stress occurred immediately after irradiation. Moreover, treatment of ascorbic acid inhibited p53 accumulation at 3 days after irradiation. Our data suggested a delayed increase of intracellular oxidative stress levels plays an important role in the process of radiation-induced cellular senescence by p53 accumulation.

  7. ING proteins in cellular senescence.

    Science.gov (United States)

    Menéndez, Camino; Abad, María; Gómez-Cabello, Daniel; Moreno, Alberto; Palmero, Ignacio

    2009-05-01

    Cellular senescence is an effective anti-tumor barrier that acts by restraining the uncontrolled proliferation of cells carrying potentially oncogenic alterations. ING proteins are putative tumor suppressor proteins functionally linked to the p53 pathway and to chromatin regulation. ING proteins exert their tumor-protective action through different types of responses. Here, we review the evidence on the participation of ING proteins, mainly ING1 and ING2, in the implementation of the senescent response. The currently available data support an important role of ING proteins as regulators of senescence, in connection with the p53 pathway and chromatin organization.

  8. P21-PARP-1 Pathway Is Involved in Cigarette Smoke-Induced Lung DNA Damage and Cellular Senescence

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    Yao, Hongwei; Sundar, Isaac K.; Gorbunova, Vera; Rahman, Irfan

    2013-01-01

    Persistent DNA damage triggers cellular senescence, which may play an important role in the pathogenesis of cigarette smoke (CS)-induced lung diseases. Both p21CDKN1A (p21) and poly(ADP-ribose) polymerase-1 (PARP-1) are involved in DNA damage and repair. However, the role of p21-PARP-1 axis in regulating CS-induced lung DNA damage and cellular senescence remains unknown. We hypothesized that CS causes DNA damage and cellular senescence through a p21-PARP-1 axis. To test this hypothesis, we determined the levels of γH2AX (a marker for DNA double-strand breaks) as well as non-homologous end joining proteins (Ku70 and Ku80) in lungs of mice exposed to CS. We found that the level of γH2AX was increased, whereas the level of Ku70 was reduced in lungs of CS-exposed mice. Furthermore, p21 deletion reduced the level of γH2AX, but augmented the levels of Ku70, Ku80, and PAR in lungs by CS. Administration of PARP-1 inhibitor 3-aminobenzamide increased CS-induced DNA damage, but lowered the levels of Ku70 and Ku80, in lungs of p21 knockout mice. Moreover, 3-aminobenzamide increased senescence-associated β-galactosidase activity, but decreased the expression of proliferating cell nuclear antigen in mouse lungs in response to CS. Interestingly, 3-aminobenzamide treatment had no effect on neutrophil influx into bronchoalveolar lavage fluid by CS. These results demonstrate that the p21-PARP-1 pathway is involved in CS-induced DNA damage and cellular senescence. PMID:24244594

  9. P21-PARP-1 pathway is involved in cigarette smoke-induced lung DNA damage and cellular senescence.

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    Hongwei Yao

    Full Text Available Persistent DNA damage triggers cellular senescence, which may play an important role in the pathogenesis of cigarette smoke (CS-induced lung diseases. Both p21(CDKN1A (p21 and poly(ADP-ribose polymerase-1 (PARP-1 are involved in DNA damage and repair. However, the role of p21-PARP-1 axis in regulating CS-induced lung DNA damage and cellular senescence remains unknown. We hypothesized that CS causes DNA damage and cellular senescence through a p21-PARP-1 axis. To test this hypothesis, we determined the levels of γH2AX (a marker for DNA double-strand breaks as well as non-homologous end joining proteins (Ku70 and Ku80 in lungs of mice exposed to CS. We found that the level of γH2AX was increased, whereas the level of Ku70 was reduced in lungs of CS-exposed mice. Furthermore, p21 deletion reduced the level of γH2AX, but augmented the levels of Ku70, Ku80, and PAR in lungs by CS. Administration of PARP-1 inhibitor 3-aminobenzamide increased CS-induced DNA damage, but lowered the levels of Ku70 and Ku80, in lungs of p21 knockout mice. Moreover, 3-aminobenzamide increased senescence-associated β-galactosidase activity, but decreased the expression of proliferating cell nuclear antigen in mouse lungs in response to CS. Interestingly, 3-aminobenzamide treatment had no effect on neutrophil influx into bronchoalveolar lavage fluid by CS. These results demonstrate that the p21-PARP-1 pathway is involved in CS-induced DNA damage and cellular senescence.

  10. Epigenetic clock analyses of cellular senescence and ageing.

    Science.gov (United States)

    Lowe, Donna; Horvath, Steve; Raj, Kenneth

    2016-02-23

    A confounding aspect of biological ageing is the nature and role of senescent cells. It is unclear whether the three major types of cellular senescence, namely replicative senescence, oncogene-induced senescence and DNA damage-induced senescence are descriptions of the same phenomenon instigated by different sources, or if each of these is distinct, and how they are associated with ageing. Recently, we devised an epigenetic clock with unprecedented accuracy and precision based on very specific DNA methylation changes that occur in function of age. Using primary cells, telomerase-expressing cells and oncogene-expressing cells of the same genetic background, we show that induction of replicative senescence (RS) and oncogene-induced senescence (OIS) are accompanied by ageing of the cell. However, senescence induced by DNA damage is not, even though RS and OIS activate the cellular DNA damage response pathway, highlighting the independence of senescence from cellular ageing. Consistent with this, we observed that telomerase-immortalised cells aged in culture without having been treated with any senescence inducers or DNA-damaging agents, re-affirming the independence of the process of ageing from telomeres and senescence. Collectively, our results reveal that cellular ageing is distinct from cellular senescence and independent of DNA damage response and telomere length.

  11. Overexpression of HDAC1 induces cellular senescence by Sp1/PP2A/pRb pathway

    Energy Technology Data Exchange (ETDEWEB)

    Chuang, Jian-Ying [Department of Pharmacology, National Cheng-Kung University, Tainan 701, Taiwan (China); Hung, Jan-Jong, E-mail: petehung@mail.ncku.edu.tw [Department of Pharmacology, National Cheng-Kung University, Tainan 701, Taiwan (China); Institute of Bioinformatics and Biosignal Transduction, National Cheng-Kung University, Tainan 701, Taiwan (China)

    2011-04-15

    Highlights: {yields} Overexpression of HDAC1 induces Sp1 deacetylation and raises Sp1/p300 complex formation to bind to PP2Ac promoter. {yields} Overexpression of HDAC1 strongly inhibits the phosphorylation of pRb through up-regulation of PP2A. {yields} Overexpressed HDAC1 restrains cell proliferaction and induces cell senescence though a novel Sp1/PP2A/pRb pathway. -- Abstract: Senescence is associated with decreased activities of DNA replication, protein synthesis, and cellular division, which can result in deterioration of cellular functions. Herein, we report that the growth and division of tumor cells were significantly repressed by overexpression of histone deacetylase (HDAC) 1 with the Tet-off induced system or transient transfection. In addition, HDAC1 overexpression led to senescence through both an accumulation of hypophosphorylated active retinoblastoma protein (pRb) and an increase in the protein level of protein phosphatase 2A catalytic subunit (PP2Ac). HDAC1 overexpression also increased the level of Sp1 deacetylation and elevated the interaction between Sp1 and p300, and subsequently that Sp1/p300 complex bound to the promoter of PP2Ac, thus leading to induction of PP2Ac expression. Similar results were obtained in the HDAC1-Tet-off stable clone. Taken together, these results indicate that HDAC1 overexpression restrained cell proliferation and induced premature senescence in cervical cancer cells through a novel Sp1/PP2A/pRb pathway.

  12. Androgen receptor drives cellular senescence.

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    Yelena Mirochnik

    Full Text Available The accepted androgen receptor (AR role is to promote proliferation and survival of prostate epithelium and thus prostate cancer progression. While growth-inhibitory, tumor-suppressive AR effects have also been documented, the underlying mechanisms are poorly understood. Here, we for the first time link AR anti-cancer action with cell senescence in vitro and in vivo. First, AR-driven senescence was p53-independent. Instead, AR induced p21, which subsequently reduced ΔN isoform of p63. Second, AR activation increased reactive oxygen species (ROS and thereby suppressed Rb phosphorylation. Both pathways were critical for senescence as was proven by p21 and Rb knock-down and by quenching ROS with N-Acetyl cysteine and p63 silencing also mimicked AR-induced senescence. The two pathways engaged in a cross-talk, likely via PML tumor suppressor, whose localization to senescence-associated chromatin foci was increased by AR activation. All these pathways contributed to growth arrest, which resolved in senescence due to concomitant lack of p53 and high mTOR activity. This is the first demonstration of senescence response caused by a nuclear hormone receptor.

  13. Pummelo Protects Doxorubicin-Induced Cardiac Cell Death by Reducing Oxidative Stress, Modifying Glutathione Transferase Expression, and Preventing Cellular Senescence

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    L. Chularojmontri

    2013-01-01

    Full Text Available Citrus flavonoids have been shown to reduce cardiovascular disease (CVD risks prominently due to their antioxidant effects. Here we investigated the protective effect of pummelo (Citrus maxima, CM fruit juice in rat cardiac H9c2 cells against doxorubicin (DOX- induced cytotoxicity. Four antioxidant compositions (ascorbic acid, hesperidin, naringin, and gallic acid were determined by HPLC. CM significantly increased cardiac cell survival from DOX toxicity as evaluated by MTT assay. Reduction of cellular oxidative stress was monitored by the formation of DCF fluorescent product and total glutathione (GSH levels. The changes in glutathione-S-transferase (GST activity and expression were determined by enzyme activity assay and Western blot analysis, respectively. Influence of CM on senescence-associated β-galactosidase activity (SA-β-gal was also determined. The mechanisms of cytoprotection involved reduction of intracellular oxidative stress, maintaining GSH availability, and enhanced GST enzyme activity and expression. DOX-induced cellular senescence was also attenuated by long-term CM treatment. Thus, CM fruit juice can be promoted as functional fruit to protect cells from oxidative cell death, enhance the phase II GSTP enzyme activity, and decrease senescence phenotype population induced by cardiotoxic agent such as DOX.

  14. YAP/TEAD-mediated transcription controls cellular senescence.

    Science.gov (United States)

    Xie, Qi; Chen, Jing; Feng, Han; Peng, Shengyi; Adams, Ursula; Bai, Yujie; Huang, Li; Li, Ji; Huang, Junjian; Meng, Songshu; Yuan, Zengqiang

    2013-06-15

    Transcription coactivator Yes-associated protein (YAP) plays an important role in the regulation of cell proliferation and apoptosis. Here, we identify a new role of YAP in the regulation of cellular senescence. We find that the expression levels of YAP proteins decrease following the replication-induced cellular senescence in IMR90 cells. Silencing of YAP inhibits cell proliferation and induces premature senescence. In additional experiments, we observe that cellular senescence induced by YAP deficiency is TEAD- and Rb/p16/p53-dependent. Furthermore, we show that Cdk6 is a direct downstream target gene of YAP in the regulation of cellular senescence, and the expression of Cdk6 is through the YAP-TEAD complex. Ectopic expression of Cdk6 rescued YAP knockdown-induced senescence. Finally, we find that downregulation of YAP in tumor cells increases senescence in response to chemotherapeutic agents, and YAP or Cdk6 expression rescues cellular senescence. Taken together, our findings define the critical role of YAP in the regulation of cellular senescence and provide a novel insight into a potential chemotherapeutic avenue for tumor suppression. ©2013 AACR.

  15. Fibroblast growth factor-23 induces cellular senescence in human mesenchymal stem cells from skeletal muscle.

    Science.gov (United States)

    Sato, Chisato; Iso, Yoshitaka; Mizukami, Takuya; Otabe, Koji; Sasai, Masahiro; Kurata, Masaaki; Sanbe, Takeyuki; Sekiya, Ichiro; Miyazaki, Akira; Suzuki, Hiroshi

    2016-02-12

    Although muscle wasting and/or degeneration are prevalent in patients with chronic kidney disease, it remains unknown whether FGF-23 influences muscle homeostasis and regeneration. Mesenchymal stem cells (MSCs) in skeletal muscle are distinct from satellite cells and have a known association with muscle degeneration. In this study we sought to investigate the effects of FGF-23 on MSCs isolated from human skeletal muscle in vitro. The MSCs expressed FGF receptors (1 through 4) and angiotensin-II type 1 receptor, but no traces of the Klotho gene were detected. MSCs and satellite cells were treated with FGF-23 and angiotensin-II for 48 h. Treatment with FGF-23 significantly decreased the number of MSCs compared to controls, while treatment with angiotensin-II did not. FGF-23 and angiotensin-II both left the cell counts of the satellite cells unchanged. The FGF-23-treated MSCs exhibited the senescent phenotype, as judged by senescence-associated β-galactosidase assay, cell morphology, and increased expression of p53 and p21 in western blot analysis. FGF-23 also significantly altered the gene expression of oxidative stress regulators in the cells. In conclusion, FGF-23 induced premature senescence in MSCs from skeletal muscle via the p53/p21/oxidative-stress pathway. The interaction between the MSCs and FGF-23 may play a key role in the impaired muscle reparative mechanisms of chronic kidney disease.

  16. 17AAG Treatment Accelerates Doxorubicin Induced Cellular Senescence: Hsp90 Interferes with Enforced Senescence of Tumor Cells.

    NARCIS (Netherlands)

    Sarangi, U.; Paithankar, K.R.; Kumar, J.U.; Subramaniam, V.; Sreedhar, A.S.

    2012-01-01

    Hsp90 chaperone has been identified as an attractive pharmacological target to combat cancer. However, some metastatic tumors either fail to respond to Hsp90 inhibition or show recovery necessitating irreversible therapeutic strategies. In response to this enforced senescence has been proposed as an

  17. Cellular Senescence: Many Roads, One Final Destination

    Directory of Open Access Journals (Sweden)

    Raya Saab

    2010-01-01

    Full Text Available Cellular senescence is a tumor-suppressor mechanism that has been shown to occur in response to multiple signals, including oncogenic stress, DNA damage, oxidative stress, telomere shortening, and other tumor-promoting insults. Over the past decade, much has been uncovered regarding the phenotype of this tumor-suppressor response and the underlying pathways necessary for its establishment. However, we have also learned that the intricate details of signaling pathways underlying senescence as a tumor-suppressor response are very much context dependent. In addition, cross-talk among pathways, and negative and positive feedback loops, all complicate our understanding of this process. This short review attempts to summarize what is known to date regarding senescence in tumor suppression, both in vitro and in vivo. Further insights into pathways necessary for senescence will hopefully identify appropriate targets for interventions to not only induce senescence as a treatment of cancerous lesions, but also to maintain this state in premalignant lesions in an effort to prevent progression to cancer.

  18. Stable cellular senescence is associated with persistent DDR activation.

    Science.gov (United States)

    Fumagalli, Marzia; Rossiello, Francesca; Mondello, Chiara; d'Adda di Fagagna, Fabrizio

    2014-01-01

    The DNA damage response (DDR) is activated upon DNA damage generation to promote DNA repair and inhibit cell cycle progression in the presence of a lesion. Cellular senescence is a permanent cell cycle arrest characterized by persistent DDR activation. However, some reports suggest that DDR activation is a feature only of early cellular senescence that is then lost with time. This challenges the hypothesis that cellular senescence is caused by persistent DDR activation. To address this issue, we studied DDR activation dynamics in senescent cells. Here we show that normal human fibroblasts retain DDR markers months after replicative senescence establishment. Consistently, human fibroblasts from healthy aged donors display markers of DDR activation even three years in culture after entry into replicative cellular senescence. However, by extending our analyses to different human cell strains, we also observed an apparent DDR loss with time following entry into cellular senescence. This though correlates with the inability of these cell strains to survive in culture upon replicative or irradiation-induced cellular senescence. We propose a model to reconcile these results. Cell strains not suffering the prolonged in vitro culture stress retain robust DDR activation that persists for years, indicating that under physiological conditions persistent DDR is causally involved in senescence establishment and maintenance. However, cell strains unable to maintain cell viability in vitro, due to their inability to cope with prolonged cell culture-associated stress, show an only-apparent reduction in DDR foci which is in fact due to selective loss of the most damaged cells.

  19. Cellular senescence induced by prolonged subculture adversely affects glutamate uptake in C6 lineage.

    Science.gov (United States)

    Pereira, Mery Stéfani Leivas; Zenki, Kamila; Cavalheiro, Marcela Mendonça; Thomé, Chairini Cássia; Filippi-Chiela, Eduardo Cremonese; Lenz, Guido; de Souza, Diogo Onofre Gomes; de Oliveira, Diogo Losch

    2014-05-01

    Several researchers have recently used C6 cells to evaluate functional properties of high-affinity glutamate transporters. However, it has been demonstrated that this lineage suffers several morphological and biochemical alterations according to the number of passages in culture. Currently, there are no reports showing whether functional properties of high-affinity glutamate transporters comply with these sub culturing-dependent modifications. The present study aimed to compare the functional properties of high-affinity glutamate transporters expressed in early (EPC6) and late (LPC6) passage C6 cells through a detailed pharmacological and biochemical characterization. Between 60-180 min of L-[(3)H]glu incubation, LPC6 presented an intracellular [(3)H] 55% lower than EPC6. Both cultures showed a time-dependent increase of intracellular [(3)H] reaching maximal levels at 120 min. Cultures incubated with D-[(3)H]asp showed a time-dependent increase of [(3)H] until 180 min. Moreover, LPC6 have a D-[(3)H]asp-derived intracellular [(3)H] 30-45% lower than EPC6 until 120 min. Only EAAT3 was immunodetected in cultures and its total content was equal between them. PMA-stimulated EAAT3 trafficking to membrane increased 50% of L-[(3)H]glu-derived intracellular [(3)H] in EPC6 and had no effect in LPC6. LPC6 displayed characteristics that resemble senescence, such as high β-Gal staining, cell enlargement and increase of large and regular nuclei. Our results demonstrated that LPC6 exhibited glutamate uptake impairment, which may have occurred due to its inability to mobilize EAAT3 to cell membrane. This profile might be related to senescent process observed in this culture. Our results suggest that LPC6 cells are an inappropriate glial cellular model to investigate the functional properties of high-affinity glutamate transporters.

  20. [Cellular senescence and chronic inflammation].

    Science.gov (United States)

    Ohtani, Naoko

    2014-01-01

    It has recently become apparent that obesity is associated with chronic inflammation and several common types of cancer development. Although several events were proposed to be involved in these pathologies, the precise mechanisms underlying obesity-associated inflammation and cancer largely remain unclear. Here, we show that senescence-associated secretory phenotype (SASP) plays crucial roles in promoting obesity-associated hepatocellular carcinoma (HCC) development in mice. Dietary or genetic obesity induces alterations of gut microbiota, thereby increasing the levels of a bacterial metabolite that cause DNA damage. The enterohepatic circulation of the bacterial metabolites provokes SASP phenotype in hepatic stellate cells (HSCs), which in turn, secretes various inflammatory and tumour promoting factors in the liver, thus facilitating HCC development in mice after exposure to chemical carcinogen. Importantly, reducing gut bacteria efficiently prevents HCC development in obese mice. Similar results were also observed in mice lacking an SASP inducer or depleted of senescent HSCs, indicating that the induction of SASP by the gut bacterial metabolite in HSCs plays key roles in obesity-associated HCC development. Interestingly, moreover, signs of SASP were also observed in the HSCs in the area of HCC arising in patients with nonalcoholic steatohepatitis (NASH), implying that a similar pathway may contribute to at least certain aspects of obesity-associated HCC development in humans as well. These findings provide valuable new insights into the development of obesity-associated cancer.

  1. Cellular senescence mediates fibrotic pulmonary disease

    Science.gov (United States)

    Schafer, Marissa J.; White, Thomas A.; Iijima, Koji; Haak, Andrew J.; Ligresti, Giovanni; Atkinson, Elizabeth J.; Oberg, Ann L.; Birch, Jodie; Salmonowicz, Hanna; Zhu, Yi; Mazula, Daniel L.; Brooks, Robert W.; Fuhrmann-Stroissnigg, Heike; Pirtskhalava, Tamar; Prakash, Y. S.; Tchkonia, Tamara; Robbins, Paul D.; Aubry, Marie Christine; Passos, João F.; Kirkland, James L.; Tschumperlin, Daniel J.; Kita, Hirohito; LeBrasseur, Nathan K.

    2017-01-01

    Idiopathic pulmonary fibrosis (IPF) is a fatal disease characterized by interstitial remodelling, leading to compromised lung function. Cellular senescence markers are detectable within IPF lung tissue and senescent cell deletion rejuvenates pulmonary health in aged mice. Whether and how senescent cells regulate IPF or if their removal may be an efficacious intervention strategy is unknown. Here we demonstrate elevated abundance of senescence biomarkers in IPF lung, with p16 expression increasing with disease severity. We show that the secretome of senescent fibroblasts, which are selectively killed by a senolytic cocktail, dasatinib plus quercetin (DQ), is fibrogenic. Leveraging the bleomycin-injury IPF model, we demonstrate that early-intervention suicide-gene-mediated senescent cell ablation improves pulmonary function and physical health, although lung fibrosis is visibly unaltered. DQ treatment replicates benefits of transgenic clearance. Thus, our findings establish that fibrotic lung disease is mediated, in part, by senescent cells, which can be targeted to improve health and function. PMID:28230051

  2. Cellular senescence and the aging brain.

    Science.gov (United States)

    Chinta, Shankar J; Woods, Georgia; Rane, Anand; Demaria, Marco; Campisi, Judith; Andersen, Julie K

    2015-08-01

    Cellular senescence is a potent anti-cancer mechanism that arrests the proliferation of mitotically competent cells to prevent malignant transformation. Senescent cells accumulate with age in a variety of human and mouse tissues where they express a complex 'senescence-associated secretory phenotype' (SASP). The SASP includes many pro-inflammatory cytokines, chemokines, growth factors and proteases that have the potential to cause or exacerbate age-related pathology, both degenerative and hyperplastic. While cellular senescence in peripheral tissues has recently been linked to a number of age-related pathologies, its involvement in brain aging is just beginning to be explored. Recent data generated by several laboratories suggest that both aging and age-related neurodegenerative diseases are accompanied by an increase in SASP-expressing senescent cells of non-neuronal origin in the brain. Moreover, this increase correlates with neurodegeneration. Senescent cells in the brain could therefore constitute novel therapeutic targets for treating age-related neuropathologies.

  3. NaDC3 Induces Premature Cellular Senescence by Promoting Transport of Krebs Cycle Intermediates, Increasing NADH, and Exacerbating Oxidative Damage.

    Science.gov (United States)

    Ma, Yuxiang; Bai, Xue-Yuan; Du, Xuan; Fu, Bo; Chen, Xiangmei

    2016-01-01

    High-affinity sodium-dependent dicarboxylate cotransporter 3 (NaDC3) is a key metabolism-regulating membrane protein responsible for transport of Krebs cycle intermediates. NaDC3 is upregulated as organs age, but knowledge regarding the underlying mechanisms by which NaDC3 modulates mammalian aging is limited. In this study, we showed that NaDC3 overexpression accelerated cellular senescence in young human diploid cells (MRC-5 and WI-38) and primary renal tubular cells, leading to cell cycle arrest in G1 phase and increased expression of senescent biomarkers, senescence-associated β-galactosidase and p16. Intracellular levels of reactive oxygen species, 8-hydroxy-2'-deoxyguanosine, malondialdehyde, and carbonyl were significantly enhanced, and activities of respiratory complexes I and III and ATP level were significantly decreased in NaDC3-infected cells. Stressful premature senescent phenotypes induced by NaDC3 were markedly ameliorated via treatment with the antioxidants Tiron and Tempol. High expression of NaDC3 caused a prominent increase in intracellular levels of Krebs cycle intermediates and NADH. Exogenous NADH and NAD(+) may aggravate and attenuate the aging phenotypes induced by NaDC3, respectively. These results suggest that NaDC3 can induce premature cellular senescence by promoting the transport of Krebs cycle intermediates, increasing generation of NADH and reactive oxygen species and leading to oxidative damage. Our results clarify the aging signaling pathway regulated by NaDC3.

  4. Stable cellular senescence is associated with persistent DDR activation.

    Directory of Open Access Journals (Sweden)

    Marzia Fumagalli

    Full Text Available The DNA damage response (DDR is activated upon DNA damage generation to promote DNA repair and inhibit cell cycle progression in the presence of a lesion. Cellular senescence is a permanent cell cycle arrest characterized by persistent DDR activation. However, some reports suggest that DDR activation is a feature only of early cellular senescence that is then lost with time. This challenges the hypothesis that cellular senescence is caused by persistent DDR activation. To address this issue, we studied DDR activation dynamics in senescent cells. Here we show that normal human fibroblasts retain DDR markers months after replicative senescence establishment. Consistently, human fibroblasts from healthy aged donors display markers of DDR activation even three years in culture after entry into replicative cellular senescence. However, by extending our analyses to different human cell strains, we also observed an apparent DDR loss with time following entry into cellular senescence. This though correlates with the inability of these cell strains to survive in culture upon replicative or irradiation-induced cellular senescence. We propose a model to reconcile these results. Cell strains not suffering the prolonged in vitro culture stress retain robust DDR activation that persists for years, indicating that under physiological conditions persistent DDR is causally involved in senescence establishment and maintenance. However, cell strains unable to maintain cell viability in vitro, due to their inability to cope with prolonged cell culture-associated stress, show an only-apparent reduction in DDR foci which is in fact due to selective loss of the most damaged cells.

  5. Caveolin-1/PTRF upregulation constitutes a mechanism for mediating p53-induced cellular senescence: implications for evidence-based therapy of delayed wound healing in diabetes.

    Science.gov (United States)

    Bitar, Milad S; Abdel-Halim, Samy M; Al-Mulla, Fahd

    2013-10-15

    A heightened state of oxidative stress and senescence of fibroblasts constitute potential therapeutic targets in nonhealing diabetic wounds. Here, we studied the underlying mechanism mediating diabetes-induced cellular senescence using in vitro cultured dermal fibroblasts and in vivo circular wounds. Our results demonstrated that the total antioxidant capacity and mRNA levels of thioredoxinreductase and glucose-6-phosphate dehydrogenase as well as the ratio of NADPH/NADP were decreased markedly in fibroblasts from patients with type 2 diabetes (DFs). Consistent with this shift in favor of excessive reactive oxygen species, DFs also displayed a significant increase in senescence-associated β-galactosidase activity and phospho-γ-histone H2AX (pH2AX) level. Moreover, the ability of PDGF to promote cell proliferation/migration and regulate the phosphorylation-dependent activation of Akt and ERK1/2 appears to be attenuated as a function of diabetes. Mechanistically, we found that diabetes-induced oxidative stress upregulated caveolin-1 (Cav-1) and PTRF expression, which in turn sequestered Mdm2 away from p53. This process resulted in the activation of a p53/p21-dependent pathway and the induction of premature senescence in DFs. Most of the aforementioned oxidative stress and senescence-based features observed in DFs were recapitulated in a 10-day-old diabetic wound. Intriguingly, we confirmed that the targeted depletion of Cav-1 or PTRF using siRNA- or Vivo-Morpholino antisense-based gene therapy markedly inhibited diabetes/oxidative stress-induced premature senescence and also accelerated tissue repair in this disease state. Overall, our data illuminate Cav-1/PTRF-1 as a key player of a novel signaling pathway that may link a heightened state of oxidative stress to cellular senescence and impaired wound healing in diabetes.

  6. Differential Roles for the Interferon-inducible IFI16 and AIM2 Innate Immune Sensors for Cytosolic DNA in Cellular Senescence of Human Fibroblasts

    Science.gov (United States)

    Duan, Xin; Ponomareva, Larissa; Veeranki, Sudhakar; Panchanathan, Ravichandran; Dickerson, Eric; Choubey, Divaker

    2011-01-01

    The interferon (IFN)-inducible IFI16 and AIM2 proteins act as innate immune sensors for cytosolic double-stranded DNA (dsDNA). Upon sensing dsDNA, the IFI16 protein induces the expression of IFN-β whereas the AIM2 protein forms an inflammasome, which promotes the secretion of IL-1β. Given that the knockdown of IFI16 expression in human diploid fibroblasts (HDFs) delays the onset of cellular senescence, we investigated the potential roles for the IFI16 and AIM2 proteins in cellular senescence. We found that increased IFI16 protein levels in old (versus young) HDFs were associated with the induction of IFN-β. In contrast, increased levels of the AIM2 protein in the senescent (versus old) HDFs were associated with increased production of IL-1β. The knockdown of type I IFN-receptor subunit-α, which reduced the basal levels of the IFI16, but not the AIM2, protein delayed the onset of cellular senescence. Accordingly, increased constitutive levels of IFI16 and AIM2 proteins in ataxia telangiectasia (AT) HDFs were associated with the activation of the IFN-signaling and increased levels of IL-1β. The IFN-β treatment of the young HDFs, which induced the expression of IFI16 and AIM2 proteins, activated a DNA-damage response and also increased basal levels of IL-1β. Interestingly, the knockdown of AIM2 expression in HDFs increased the basal levels of IFI16 protein and activated the IFN-signaling. In contrast, the knockdown of the IFI16 expression in HDFs decreased the basal and dsDNA-induced activation of the IFN-signaling. Collectively, our observations demonstrate differential roles for the IFI16 and AIM2 proteins in cellular senescence and associated secretory phenotype. PMID:21471287

  7. ATM Couples Replication Stress and Metabolic Reprogramming during Cellular Senescence

    Directory of Open Access Journals (Sweden)

    Katherine M. Aird

    2015-05-01

    Full Text Available Replication stress induced by nucleotide deficiency plays an important role in cancer initiation. Replication stress in primary cells typically activates the cellular senescence tumor-suppression mechanism. Senescence bypass correlates with development of cancer, a disease characterized by metabolic reprogramming. However, the role of metabolic reprogramming in the cellular response to replication stress has been little explored. Here, we report that ataxia telangiectasia mutated (ATM plays a central role in regulating the cellular response to replication stress by shifting cellular metabolism. ATM inactivation bypasses senescence induced by replication stress triggered by nucleotide deficiency. This was due to restoration of deoxyribonucleotide triphosphate (dNTP levels through both upregulation of the pentose phosphate pathway via increased glucose-6-phosphate dehydrogenase (G6PD activity and enhanced glucose and glutamine consumption. These phenotypes were mediated by a coordinated suppression of p53 and upregulation of c-MYC downstream of ATM inactivation. Our data indicate that ATM status couples replication stress and metabolic reprogramming during senescence.

  8. Adiponectin corrects premature cellular senescence and normalizes antimicrobial peptide levels in senescent keratinocytes.

    Science.gov (United States)

    Jin, Taewon; Kim, Min Jeong; Heo, Won Il; Park, Kui Young; Choi, Sun Young; Lee, Mi-Kyung; Hong, Seung-Phil; Kim, Seong-Jin; Im, Myung; Moon, Nam Ju; Seo, Seong Jun

    2016-09-02

    Stress-induced premature senescence or aging causes dysfunction in the human somatic system. Adiponectin (Acrp30) plays a role in functional recovery, especially with adenosine 3',5'-monophosphate (AMP)-activated protein kinase (AMPK) and silent mating type information regulation 2 homolog 1 (SIRT1). Acrp30 stimulation reduced the premature senescence positive ratio induced by hydrogen peroxide (H2O2) and restituted human β-defensin 2 (hBD-2) levels in senescent keratinocytes. Acrp30 recovered AMPK activity in senescent keratinocytes and increased SIRT1 deacetylation activity. As a result, FoxO1 and FoxO3 transcription activity was recovered. Additionally, Acrp30 stimulation suppresses NFκB p65, which induces abnormal expression of hBD-2 induced by H2O2. In the present study, we have shown that Acrp30 reduces premature senescence and recovers cellular function in keratinocytes. These results suggest a role for Acrp30 as an anti-aging agent to improve impaired skin immune barriers. Copyright © 2016 Elsevier Inc. All rights reserved.

  9. [Research progress of cellular senescence and senescent secretary phenotype in intervertebral disc degeneration].

    Science.gov (United States)

    Wang, Feng; Zheng, Chenjingmei; Wu, Xiaotao

    2012-12-01

    To summarize the role of cellular senescence and senescent secretary phenotype in the intervertebral disc (IVD) degeneration. Relevant articles that discussed the roles of cellular senescence in the IVD degeneration were extensively reviewed, and retrospective and comprehensive analysis was performed. The senescent phenomenon during IVD degeneration, senescent secretary phenotype of the disc cells, senescent pathways within the IVD microenvironment, as well as the anti-senescent approaches for IVD regeneration were systematically reviewed. During aging and degeneration, IVD cells gradually and/or prematurely undergo senescence by activating p53-p21-retinoblastoma (RB) or p161NK4A-RB senescent pathways. The accumulation of senescent cells not only decreases the self-renewal ability of IVD, but also deteriorates the disc microenvironment by producing more inflammatory cytokines and matrix degrading enzymes. More specific senescent biomarkers are required to fully understand the phenotype change of senescent disc cells during IVD degeneration. Molecular analysis of the senescent disc cells and their intracellular signaling pathways are needed to get a safer and more efficient anti-senescence strategy for IVD regeneration. Cellular senescence is an important mechanism by which IVD cells decrease viability and degenerate biological behaviors, which provide a new thinking to understand the pathogenesis of IVD degeneration.

  10. Aberrant localization of lamin B receptor (LBR) in cellular senescence in human cells

    Energy Technology Data Exchange (ETDEWEB)

    Arai, Rumi; En, Atsuki; Ukekawa, Ryo [Graduate School of Nanobioscience, Yokohama City University, 22-2 Seto, Kanazawa-ku, Yokohama 236-0027 (Japan); Miki, Kensuke [Graduate School of Nanobioscience, Yokohama City University, 22-2 Seto, Kanazawa-ku, Yokohama 236-0027 (Japan); Ichiban Life Corporation, 1-1-7 Horai-cho, Naka-ku, Yokohama 231-0048 (Japan); Fujii, Michihiko, E-mail: mifuji@yokohama-cu.ac.jp [Graduate School of Nanobioscience, Yokohama City University, 22-2 Seto, Kanazawa-ku, Yokohama 236-0027 (Japan); Ayusawa, Dai [Graduate School of Nanobioscience, Yokohama City University, 22-2 Seto, Kanazawa-ku, Yokohama 236-0027 (Japan); Ichiban Life Corporation, 1-1-7 Horai-cho, Naka-ku, Yokohama 231-0048 (Japan)

    2016-05-13

    5-Bromodeoxyuridine (BrdU), a thymidine analogue, induces cellular senescence in mammalian cells. BrdU induces cellular senescence probably through the regulation of chromatin because BrdU destabilizes or disrupts nucleosome positioning and decondenses heterochromatin. Since heterochromatin is tethered to the nuclear periphery through the interaction with the nuclear envelope proteins, we examined the localization of the several nuclear envelope proteins such as lamins, lamin-interacting proteins, nuclear pore complex proteins, and nuclear transport proteins in senescent cells. We have shown here that lamin B receptor (LBR) showed a change in localization in both BrdU-induced and replicative senescent cells.

  11. PKCι depletion initiates mitotic slippage-induced senescence in glioblastoma.

    Science.gov (United States)

    Restall, Ian J; Parolin, Doris A E; Daneshmand, Manijeh; Hanson, Jennifer E L; Simard, Manon A; Fitzpatrick, Megan E; Kumar, Ritesh; Lavictoire, Sylvie J; Lorimer, Ian A J

    2015-01-01

    Cellular senescence is a tumor suppressor mechanism where cells enter a permanent growth arrest following cellular stress. Oncogene-induced senescence (OIS) is induced in non-malignant cells following the expression of an oncogene or inactivation of a tumor suppressor. Previously, we have shown that protein kinase C iota (PKCι) depletion induces cellular senescence in glioblastoma cells in the absence of a detectable DNA damage response. Here we demonstrate that senescent glioblastoma cells exhibit an aberrant centrosome morphology. This was observed in basal levels of senescence, in p21-induced senescence, and in PKCι depletion-induced senescence. In addition, senescent glioblastoma cells are polyploid, Ki-67 negative and arrest at the G1/S checkpoint, as determined by expression of cell cycle regulatory proteins. These markers are all consistent with cells that have undergone mitotic slippage. Failure of the spindle assembly checkpoint to function properly can lead to mitotic slippage, resulting in the premature exit of mitotic cells into the G1 phase of the cell cycle. Although in G1, these cells have the replicated DNA and centrosomal phenotype of a cell that has entered mitosis and failed to divide. Overall, we demonstrate that PKCι depletion initiates mitotic slippage-induced senescence in glioblastoma cells. To our knowledge, this is the first evidence of markers of mitotic slippage directly in senescent cells by co-staining for senescence-associated β-galactosidase and immunofluorescence markers in the same cell population. We suggest that markers of mitotic slippage be assessed in future studies of senescence to determine the extent of mitotic slippage in the induction of cellular senescence.

  12. The ING tumor suppressors in cellular senescence and chromatin.

    Science.gov (United States)

    Ludwig, Susann; Klitzsch, Alexandra; Baniahmad, Aria

    2011-07-18

    The Inhibitor of Growth (ING) proteins represent a type II tumor suppressor family comprising five conserved genes, ING1 to ING5. While ING1, ING2 and ING3 proteins are stable components of the mSIN3a-HDAC complexes, the association of ING1, ING4 and ING5 with HAT protein complexes was also reported. Among these the ING1 and ING2 have been analyzed more deeply. Similar to other tumor suppressor factors the ING proteins are also involved in many cellular pathways linked to cancer and cell proliferation such as cell cycle regulation, cellular senescence, DNA repair, apoptosis, inhibition of angiogenesis and modulation of chromatin.A common structural feature of ING factors is the conserved plant homeodomain (PHD), which can bind directly to the histone mark trimethylated lysine of histone H3 (H3K4me3). PHD mutants lose the ability to undergo cellular senescence linking chromatin mark recognition with cellular senescence. ING1 and ING2 are localized in the cell nucleus and associated with chromatin modifying enzymes, linking tumor suppression directly to chromatin regulation. In line with this, the expression of ING1 in tumors is aberrant or identified point mutations are mostly localized in the PHD finger and affect histone binding. Interestingly, ING1 protein levels increase in replicative senescent cells, latter representing an efficient pathway to inhibit cancer proliferation. In association with this, suppression of p33ING1 expression prolongs replicative life span and is also sufficient to bypass oncogene-induced senescence. Recent analyses of ING1- and ING2-deficient mice confirm a tumor suppressive role of ING1 and ING2 and also indicate an essential role of ING2 in meiosis.Here we summarize the activity of ING1 and ING2 as tumor suppressors, chromatin factors and in development.

  13. Stress-Induced Premature Senescence or Stress-Induced Senescence-Like Phenotype: One In Vivo Reality, Two Possible Definitions?

    Directory of Open Access Journals (Sweden)

    Olivier Toussaint

    2002-01-01

    Full Text Available No consensus exists so far on the definition of cellular senescence. The narrowest definition of senescence is irreversible growth arrest triggered by telomere shortening counting cell generations (definition 1. Other authors gave an enlarged functional definition encompassing any kind of irreversible arrest of proliferative cell types induced by damaging agents or cell cycle deregulations after overexpression of proto-oncogenes (definition 2. As stress increases, the proportion of cells in “stress-induced premature senescence-like phenotype” according to definition 1 or “stress-induced premature senescence,” according to definition 2, should increase when a culture reaches growth arrest, and the proportion of cells that reached telomere-dependent replicative senescence due to the end-replication problem should decrease. Stress-induced premature senescence-like phenotype and telomere-dependent replicatively senescent cells share basic similarities such as irreversible growth arrest and resistance to apoptosis, which may appear through different pathways. Irreversible growth arrest after exposure to oxidative stress and generation of DNA damage could be as efficient in avoiding immortalisation as “telomere-dependent” replicative senescence. Probabilities are higher that the senescent cells (according to definition 2 appearing in vivo are in stress-induced premature senescence rather than in telomere-dependent replicative senescence. Examples are given suggesting these cells affect in vivo tissue (pathophysiology and aging.

  14. Cellular senescence in normal and premature lung aging.

    Science.gov (United States)

    Bartling, B

    2013-10-01

    The incidence of chronic respiratory diseases (e.g., chronic obstructive pulmonary disease, COPD) and interstitial lung diseases (e.g., pneumonia and lung fibrosis) increases with age. In addition to immune senescence, the accumulation of senescent cells directly in lung tissue might play a critical role in the increased prevalence of these pulmonary diseases. In the last couple of years, detailed studies have identified the presence of senescent cells in the aging lung and in diseased lungs of patients with COPD and lung fibrosis. Cellular senescence has been shown for epithelial cells of bronchi and alveoli as well as mesenchymal and vascular cells. Known risk factors for pulmonary diseases (cigarette smoke, air pollutions, bacterial infections, etc.) were identified in experimental studies as being possible mediators in the development of cellular senescence. The present findings indicate the importance of cellular senescence in normal lung aging and in premature aging of the lung in patients with COPD, lung fibrosis, and probably other respiratory diseases.

  15. Glycerophospholipid profile in oncogene-induced senescence.

    Science.gov (United States)

    Cadenas, Cristina; Vosbeck, Sonja; Hein, Eva-Maria; Hellwig, Birte; Langer, Alice; Hayen, Heiko; Franckenstein, Dennis; Büttner, Bettina; Hammad, Seddik; Marchan, Rosemarie; Hermes, Matthias; Selinski, Silvia; Rahnenführer, Jörg; Peksel, Begüm; Török, Zsolt; Vígh, László; Hengstler, Jan G

    2012-09-01

    Alterations in lipid metabolism and in the lipid composition of cellular membranes are linked to the pathology of numerous diseases including cancer. However, the influence of oncogene expression on cellular lipid profile is currently unknown. In this work we analyzed changes in lipid profiles that are induced in the course of ERBB2-expression mediated premature senescence. As a model system we used MCF-7 breast cancer cells with doxycycline-inducible expression of NeuT, an oncogenic ERBB2 variant. Affymetrix gene array data showed NeuT-induced alterations in the transcription of many enzymes involved in lipid metabolism, several of which (ACSL3, CHPT1, PLD1, LIPG, MGLL, LDL and NPC1) could be confirmed by quantitative realtime PCR. A study of the glycerophospholipid and lyso-glycerophospholipid profiles, obtained by high performance liquid chromatography coupled to Fourier-transform ion cyclotron resonance-mass spectrometry revealed senescence-associated changes in numerous lipid species, including mitochondrial lipids. The most prominent changes were found in PG(34:1), PG(36:1) (increased) and LPE(18:1), PG(40:7) and PI(36:1) (decreased). Statistical analysis revealed a general trend towards shortened phospholipid acyl chains in senescence and a significant trend to more saturated acyl chains in the class of phosphatidylglycerol. Additionally, the cellular cholesterol content was elevated and accumulated in vacuoles in senescent cells. These changes were accompanied by increased membrane fluidity. In mitochondria, loss of membrane potential along with altered intracellular distribution was observed. In conclusion, we present a comprehensive overview of altered cholesterol and glycerophospholipid patterns in senescence, showing that predominantly mitochondrial lipids are affected and lipid species less susceptible to peroxidation are increased.

  16. IGF-I enhances cellular senescence via the reactive oxygen species-p53 pathway

    Energy Technology Data Exchange (ETDEWEB)

    Handayaningsih, Anastasia-Evi; Takahashi, Michiko; Fukuoka, Hidenori; Iguchi, Genzo; Nishizawa, Hitoshi; Yamamoto, Masaaki; Suda, Kentaro [Division of Diabetes and Endocrinology, Department of Internal Medicine, Kobe University Graduate School of Medicine, Kobe (Japan); Takahashi, Yutaka, E-mail: takahash@med.kobe-u.ac.jp [Division of Diabetes and Endocrinology, Department of Internal Medicine, Kobe University Graduate School of Medicine, Kobe (Japan)

    2012-08-24

    Highlights: Black-Right-Pointing-Pointer Cellular senescence plays an important role in tumorigenesis and aging process. Black-Right-Pointing-Pointer We demonstrated IGF-I enhanced cellular senescence in primary confluent cells. Black-Right-Pointing-Pointer IGF-I enhanced cellular senescence in the ROS and p53-dependent manner. Black-Right-Pointing-Pointer These results may explain the underlying mechanisms of IGF-I involvement in tumorigenesis and in regulation of aging. -- Abstract: Cellular senescence is characterized by growth arrest, enlarged and flattened cell morphology, the expression of senescence-associated {beta}-galactosidase (SA-{beta}-gal), and by activation of tumor suppressor networks. Insulin-like growth factor-I (IGF-I) plays a critical role in cellular growth, proliferation, tumorigenesis, and regulation of aging. In the present study, we show that IGF-I enhances cellular senescence in mouse, rat, and human primary cells in the confluent state. IGF-I induced expression of a DNA damage marker, {gamma}H2AX, the increased levels of p53 and p21 proteins, and activated SA-{beta}-gal. In the confluent state, an altered downstream signaling of IGF-I receptor was observed. Treatment with a reactive oxygen species (ROS) scavenger, N-acetylcystein (NAC) significantly suppressed induction of these markers, indicating that ROS are involved in the induction of cellular senescence by IGF-I. In p53-null mouse embryonic fibroblasts, the IGF-I-induced augmentation of SA-{beta}-gal and p21 was inhibited, demonstrating that p53 is required for cellular senescence induced by IGF-I. Thus, these data reveal a novel pathway whereby IGF-I enhances cellular senescence in the ROS and p53-dependent manner and may explain the underlying mechanisms of IGF-I involvement in tumorigenesis and in regulation of aging.

  17. Cellular senescence and tumor suppressor gene p16.

    Science.gov (United States)

    Rayess, Hani; Wang, Marilene B; Srivatsan, Eri S

    2012-04-15

    Cellular senescence is an irreversible arrest of cell growth. Biochemical and morphological changes occur during cellular senescence, including the formation of a unique cellular morphology such as flattened cytoplasm. Function of mitochondria, endoplasmic reticulum and lysosomes are affected resulting in the inhibition of lysosomal and proteosomal pathways. Cellular senescence can be triggered by a number of factors including, aging, DNA damage, oncogene activation and oxidative stress. While the molecular mechanism of senescence involves p16 and p53 tumor suppressor genes and telomere shortening, this review is focused on the mechanism of p16 control. The p16-mediated senescence acts through the retinoblastoma (Rb) pathway inhibiting the action of the cyclin dependant kinases leading to G1 cell cycle arrest. Rb is maintained in a hypophosphorylated state resulting in the inhibition of transcription factor E2F1. Regulation of p16 expression is complex and involves epigenetic control and multiple transcription factors. PRC1 (Pombe repressor complex (1) and PRC2 (Pombe repressor complex (2) proteins and histone deacetylases play an important role in the promoter hypermethylation for suppressing p16 expression. While transcription factors YY1 and Id1 suppress p16 expression, transcription factors CTCF, Sp1 and Ets family members activate p16 transcription. Senescence occurs with the inactivation of suppressor elements leading to the enhanced expression of p16. Copyright © 2011 UICC.

  18. Identification of 30 protein species involved in replicative senescence and stress-induced premature senescence

    DEFF Research Database (Denmark)

    Dierick, Jean François; Kalume, Dário E; Wenders, Frédéric

    2002-01-01

    Exposure of human proliferative cells to subcytotoxic stress triggers stress-induced premature senescence (SIPS) which is characterized by many biomarkers of replicative senescence. Proteomic comparison of replicative senescence and stress-induced premature senescence indicates that, at the level....... These changes affect different cell functions, including energy metabolism, defense systems, maintenance of the redox potential, cell morphology and transduction pathways.......Exposure of human proliferative cells to subcytotoxic stress triggers stress-induced premature senescence (SIPS) which is characterized by many biomarkers of replicative senescence. Proteomic comparison of replicative senescence and stress-induced premature senescence indicates that, at the level...... of protein expression, stress-induced premature senescence and replicative senescence are different phenotypes sharing however similarities. In this study, we identified 30 proteins showing changes of expression level specific or common to replicative senescence and/or stress-induced premature senescence...

  19. Absence of AMPKα2 accelerates cellular senescence via p16 induction in mouse embryonic fibroblasts.

    Science.gov (United States)

    Ding, Ye; Chen, Jie; Okon, Imoh Sunday; Zou, Ming-Hui; Song, Ping

    2016-02-01

    Emerging evidence suggests that activation of adenosine monophosphate-activated protein kinase (AMPK), an energy gauge and redox sensor, delays aging process. However, the molecular mechanisms by which AMPKα isoform regulates cellular senescence remain largely unknown. The aim of this study was to determine if AMPKα deletion contributes to the accelerated cell senescence by inducing p16(INK4A) (p16) expression thereby arresting cell cycle. The markers of cellular senescence, cell cycle proteins, and reactive oxygen species (ROS) were monitored in cultured mouse embryonic fibroblasts (MEFs) isolated from wild type (WT, C57BL/6J), AMPKα1, or AMPKα2 homozygous deficient (AMPKα1(-/-), AMPKα2(-/-)) mice by Western blot and cellular immunofluorescence staining, as well as immunohistochemistry (IHC) in skin tissue of young and aged mice. Deletion of AMPKα2, the minor isoform of AMPKα, but not AMPKα1 in high-passaged MEFs led to spontaneous cell senescence demonstrated by accumulation of senescence-associated-β-galactosidase (SA-β-gal) staining and foci formation of heterochromatin protein 1 homolog gamma (HP1γ). It was shown here that AMPKα2 deletion upregulates cyclin-dependent kinase (CDK) inhibitor, p16, which arrests cell cycle. Furthermore, AMPKα2 null cells exhibited elevated ROS production. Interestingly, knockdown of HMG box-containing protein 1 (HBP1) partially blocked the cellular senescence of AMPKα2-deleted MEFs via the reduction of p16. Finally, dermal cells senescence, including fibroblasts senescence evidenced by the staining of p16, HBP1, and Ki-67, in the skin of aged AMPKα2(-/-) mice was enhanced when compared with that in wild type mice. Taken together, our results suggest that AMPKα2 isoform plays a fundamental role in anti-oxidant stress and anti-senescence.

  20. Inhibitory role of peroxiredoxin II (Prx II) on cellular senescence.

    Science.gov (United States)

    Han, Ying-Hao; Kim, Hyun-Sun; Kim, Jin-Man; Kim, Sang-Keun; Yu, Dae-Yeul; Moon, Eun-Yi

    2005-08-29

    Reactive oxygen species (ROS) were generated in all oxygen-utilizing organisms. Peroxiredoxin II (Prx II) as one of antioxidant enzymes may play a protective role against the oxidative damage caused by ROS. In order to define the role of Prx II in organismal aging, we evaluated cellular senescence in Prx II(-/-) mouse embryonic fibroblast (MEF). As compared to wild type MEF, cellular senescence was accelerated in Prx II(-/-) MEF. Senescence-associated (SA)-beta-galactosidase (Gal)-positive cell formation was about 30% higher in Prx II(-/-) MEF. N-Acetyl-l-cysteine (NAC) treatment attenuated SA-beta-Gal-positive cell formation. Prx II(-/-) MEF exhibited the higher G2/M (41%) and lower S (1.6%) phase cells as compared to 24% and 7.3% [corrected] in wild type MEF, respectively. A high increase in the p16 and a slight increase in the p21 and p53 levels were detected in PrxII(-/-) MEF cells. The cellular senescence of Prx II(-/-) MEF was correlated with the organismal aging of Prx II(-/-) mouse skin. While extracellular signal-regulated kinase (ERK) and p38 activation was detected in Prx II(-/-) MEF, ERK and c-Jun N-terminal kinase (JNK) activation was detected in Prx II(-/-) skin. These results suggest that Prx II may function as an enzymatic antioxidant to prevent cellular senescence and skin aging.

  1. Cellular Senescence and the Biology of Aging, Disease, and Frailty.

    Science.gov (United States)

    LeBrasseur, Nathan K; Tchkonia, Tamara; Kirkland, James L

    2015-01-01

    Population aging simultaneously highlights the remarkable advances in science, medicine, and public policy, and the formidable challenges facing society. Indeed, aging is the primary risk factor for many of the most common chronic diseases and frailty, which result in profound social and economic costs. Population aging also reveals an opportunity, i.e. interventions to disrupt the fundamental biology of aging could significantly delay the onset of age-related conditions as a group, and, as a result, extend the healthy life span, or health span. There is now considerable evidence that cellular senescence is an underlying mechanism of aging and age-related conditions. Cellular senescence is a process in which cells lose the ability to divide and damage neighboring cells by the factors they secrete, collectively referred to as the senescence-associated secretory phenotype (SASP). Herein, we discuss the concept of cellular senescence, review the evidence that implicates cellular senescence and SASP in age-related deterioration, hyperproliferation, and inflammation, and propose that this underlying mechanism of aging may play a fundamental role in the biology of frailty.

  2. SM22{alpha}-induced activation of p16{sup INK4a}/retinoblastoma pathway promotes cellular senescence caused by a subclinical dose of {gamma}-radiation and doxorubicin in HepG2 cells

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Tae Rim; Lee, Hee Min; Lee, So Yong; Kim, Eun Jin; Kim, Kug Chan [Department of Radiation Biology, Environmental Radiation Research Group, Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of); Paik, Sang Gi [Department of Biology, School of Biosciences and Biotechnology, Chungnam National University, Daejeon (Korea, Republic of); Cho, Eun Wie, E-mail: ewcho@kribb.re.kr [Daejeon-KRIBB-FHCRC Cooperation Research Center, Korea Research Institute of Bioscience and Biotechnology, Daejeon (Korea, Republic of); Kim, In Gyu, E-mail: igkim@kaeri.re.kr [Department of Radiation Biology, Environmental Radiation Research Group, Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2010-09-10

    Research highlights: {yields} SM22{alpha} overexpression in HepG2 cells leads cells to a growth arrest state, and the treatment of a subclinical dose of {gamma}-radiation or doxorubicin promotes cellular senescence. {yields} SM22{alpha} overexpression elevates p16{sup INK4a} followed by pRB activation, but there are no effects on p53/p21{sup WAF1/Cip1} pathway. {yields} SM22{alpha}-induced MT-1G activates p16{sup INK4a}/pRB pathway, which promotes cellular senescence by damaging agents. -- Abstract: Smooth muscle protein 22-alpha (SM22{alpha}) is known as a transformation- and shape change-sensitive actin cross-linking protein found in smooth muscle tissue and fibroblasts; however, its functional role remains uncertain. We reported previously that SM22{alpha} overexpression confers resistance against anti-cancer drugs or radiation via induction of metallothionein (MT) isozymes in HepG2 cells. In this study, we demonstrate that SM22{alpha} overexpression leads cells to a growth arrest state and promotes cellular senescence caused by treatment with a subclinical dose of {gamma}-radiation (0.05 and 0.1 Gy) or doxorubicin (0.01 and 0.05 {mu}g/ml), compared to control cells. Senescence growth arrest is known to be controlled by p53 phosphorylation/p21{sup WAF1/Cip1} induction or p16{sup INK4a}/retinoblastoma protein (pRB) activation. SM22{alpha} overexpression in HepG2 cells elevated p16{sup INK4a} followed by pRB activation, but did not activate the p53/p21{sup WAF1/Cip1} pathway. Moreover, MT-1G, which is induced by SM22{alpha} overexpression, was involved in the activation of the p16{sup INK4a}/pRB pathway, which led to a growth arrest state and promoted cellular senescence caused by damaging agents. Our findings provide the first demonstration that SM22{alpha} modulates cellular senescence caused by damaging agents via regulation of the p16{sup INK4a}/pRB pathway in HepG2 cells and that these effects of SM22{alpha} are partially mediated by MT-1G.

  3. Detection of cellular senescence within human invasive breast carcinomas distinguishes different breast tumor subtypes.

    Science.gov (United States)

    Cotarelo, Cristina L; Schad, Arno; Kirkpatrick, Charles James; Sleeman, Jonathan P; Springer, Erik; Schmidt, Marcus; Thaler, Sonja

    2016-11-15

    Oncogene-induced senescence is thought to act as a barrier to tumorigenesis by arresting cells at risk of malignant transformation. Nevertheless, numerous findings suggest that senescent cells may conversely promote tumor progression through the development of the senescence-associated secretome they produce. It is likely that the composition and the physiological consequences mediated by the senescence secretome are dependent on the oncogenes that trigger the senescence program. Breast cancer represents a heterogenous disease that can be divided into breast cancer subtypes due to different subsets of genetic and epigenetic abnormalities. As tumor initiation and progression of these breast cancer subtypes is triggered by diverse oncogenic stimuli, differences in the senescence secretomes within breast tumors might be responsible for tumor initiation, progression, metastasis and therapeutic response. Many studies have addressed the role of senescence as a barrier to tumor progression using murine xenograft models. However, few investigations have been performed to elucidate the degree to which senescent tumor cells are present within untreated human tumors, and if present, whether these senescent tumor cells may play a role in disease progression. In the present study we analysed the appearance of senescent cells within invasive breast cancers. Detection of cellular senescence by the use of SAβ-galactosidase (SAβ-gal) staining within invasive breast carcinoms from 129 untreated patients revealed differences in the amount of SAβ-gal+ tumor cells between breast cancer subtypes. The highest percentages of SAβ-gal+ tumor cells were found in HER2-positive and luminal A breast carcinomas whereas triple negative tumors showed either little or no positivity.

  4. Gamma-H2AX upregulation caused by Wip1 deficiency increases depression-related cellular senescence in hippocampus

    Science.gov (United States)

    He, Zhi-Yong; Wang, Wen-Yue; Hu, Wei-Yan; Yang, Lu; Li, Yan; Zhang, Wei-Yuan; Yang, Ya-Shu; Liu, Si-Cheng; Zhang, Feng-Lan; Mei, Rong; Xing, Da; Xiao, Zhi-Cheng; Zhang, Ming

    2016-01-01

    The PP2C family member Wild-type p53-induced phosphatase 1 (Wip1) critically regulates DNA damage response (DDR) under stressful situations. In the present study, we investigated whether Wip1 expression was involved in the regulation of DDR-induced and depression-related cellular senescence in mouse hippocampus. We found that Wip1 gene knockout (KO) mice showed aberrant elevation of hippocampal cellular senescence and of γ-H2AX activity, which is known as a biomarker of DDR and cellular senescence, indicating that the lack of Wip1-mediated γ-H2AX dephosphorylation facilitates cellular senescence in hippocampus. Administration of the antidepressant fluoxetine had no significant effects on the increased depression-like behaviors, enriched cellular senescence, and aberrantly upregulated hippocampal γ-H2AX activity in Wip1 KO mice. After wildtype C57BL/6 mice were exposed to the procedure of chronic unpredictable mild stress (CUMS), cellular senescence and γ-H2AX activity in hippocampus were also elevated, accompanied by the suppression of Wip1 expression in hippocampus when compared to the control group without CUMS experience. These CUMS-induced symptoms were effectively prevented following fluoxetine administration in wildtype C57BL/6 mice, with the normalization of depression-like behaviors. Our data demonstrate that Wip1-mediated γ-H2AX dephosphorylation may play an important role in the occurrence of depression-related cellular senescence. PMID:27686532

  5. Regulation of cellular senescence by the essential caveolar component PTRF/Cavin-1

    Institute of Scientific and Technical Information of China (English)

    Lin Bai; Xiaoli Deng; Juanjuan Li; Miao Wang; Qian Li; Wei An; Deli A; Yu-Sheng Cong

    2011-01-01

    Polymerase I and transcript release factor (PTRF, also known as Cavin-1) is an essential component in the biogenesis and function of caveolae. Here, we show that PTRF expression is increased in senescent human fibroblasts.Importantly, overexpression of PTRF induced features characteristic of cellular senescence, whereas reduced PTRF expression extended the cellular replicative lifespan. Interestingly, we found that PTRF localized primarily to the nuclei of young and quiescent WI-38 human fibroblasts, but translocated to the cytosol and plasma membrane during cellular senescence. Furthermore, electron microscopic analysis demonstrated an increased number of caveolar structures in senescent and PTRF-transfected WI-38 cells. Our data suggest that the role of PTRF in cellular senes cence is dependent on its targeting to caveolae and its interaction with caveolin-l, which appeared to be regulated by the phosphorylation of PTRF. Taken together, our findings identify PTRF as a novel regulator of cellular senescence that acts through the p53/p21 and caveolar pathways.

  6. Quantitative model of cell cycle arrest and cellular senescence in primary human fibroblasts.

    Directory of Open Access Journals (Sweden)

    Sascha Schäuble

    Full Text Available Primary human fibroblasts in tissue culture undergo a limited number of cell divisions before entering a non-replicative "senescent" state. At early population doublings (PD, fibroblasts are proliferation-competent displaying exponential growth. During further cell passaging, an increasing number of cells become cell cycle arrested and finally senescent. This transition from proliferating to senescent cells is driven by a number of endogenous and exogenous stress factors. Here, we have developed a new quantitative model for the stepwise transition from proliferating human fibroblasts (P via reversibly cell cycle arrested (C to irreversibly arrested senescent cells (S. In this model, the transition from P to C and to S is driven by a stress function γ and a cellular stress response function F which describes the time-delayed cellular response to experimentally induced irradiation stress. The application of this model based on senescence marker quantification at the single-cell level allowed to discriminate between the cellular states P, C, and S and delivers the transition rates between the P, C and S states for different human fibroblast cell types. Model-derived quantification unexpectedly revealed significant differences in the stress response of different fibroblast cell lines. Evaluating marker specificity, we found that SA-β-Gal is a good quantitative marker for cellular senescence in WI-38 and BJ cells, however much less so in MRC-5 cells. Furthermore we found that WI-38 cells are more sensitive to stress than BJ and MRC-5 cells. Thus, the explicit separation of stress induction from the cellular stress response, and the differentiation between three cellular states P, C and S allows for the first time to quantitatively assess the response of primary human fibroblasts towards endogenous and exogenous stress during cellular ageing.

  7. Human endothelial senescence can be induced by TNF-α

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    TNF-α is one of the most important proinfiammatory cytokines in mediating multiple physio-pathological functions during immunological responses. Vascular endothelial cells, when stimulated by TNF-α2 can increase the expression of multiple cytokines and cellular adhesion molecules and, in turn, actively promote the inflammatory responses by recruiting and activating of leukocytes to the inflammatory site. In addition to endothelial death induced by TNF-α2 we found for the first time that TNF-α can also induce the human endothelial cells senescence. The induced senescent endothelial cells will display SA-β-Gal staining and they were arrested in G0-G1 phase. We found that Aψm would always be up-regulated in response to TNF-α stimulation at early time but when the cells become senescent, A ψmshows a tendency to decrease. It may reflect the sthenic function of mitochondria at early time in response to TNF-αstimulation and decay when the endothelial cells were induced senescent. ROS fluctuates at early time and also decreases when the endothelial cells become senescent. Our results show that the change of mitochondrial function may be related to the senescent process.``

  8. RNA methyltransferase NSUN2 promotes stress-induced HUVEC senescence.

    Science.gov (United States)

    Cai, Xiaoyu; Hu, Yuanyuan; Tang, Hao; Hu, Han; Pang, Lijun; Xing, Junyue; Liu, Zhenyun; Luo, Yuhong; Jiang, Bin; Liu, Te; Gorospe, Myriam; Chen, Chuan; Wang, Wengong

    2016-04-12

    The tRNA methyltransferase NSUN2 delays replicative senescence by regulating the translation of CDK1 and CDKN1B mRNAs. However, whether NSUN2 influences premature cellular senescence remains untested. Here we show that NSUN2 methylates SHC mRNA in vitro and in cells, thereby enhancing the translation of the three SHC proteins, p66SHC, p52SHC, and p46SHC. Our results further show that the elevation of SHC expression by NSUN2-mediated mRNA methylation increased the levels of ROS, activated p38MAPK, thereby accelerating oxidative stress- and high-glucose-induced senescence of human vascular endothelial cells (HUVEC). Our findings highlight the critical impact of NSUN2-mediated mRNA methylation in promoting premature senescence.

  9. Dysfunction of nucleus accumbens-1 activates cellular senescence and inhibits tumor cell proliferation and oncogenesis.

    Science.gov (United States)

    Zhang, Yi; Cheng, Yan; Ren, Xingcong; Hori, Tsukasa; Huber-Keener, Kathryn J; Zhang, Li; Yap, Kai Lee; Liu, David; Shantz, Lisa; Qin, Zheng-Hong; Zhang, Suping; Wang, Jianrong; Wang, Hong-Gang; Shih, Ie-Ming; Yang, Jin-Ming

    2012-08-15

    Nucleus accumbens-1 (NAC1), a nuclear factor belonging to the BTB/POZ gene family, has emerging roles in cancer. We report here that NAC1 acts as a negative regulator of cellular senescence in transformed and nontransformed cells, and dysfunction of NAC1 induces senescence and inhibits its oncogenic potential. We show that NAC1 deficiency markedly activates senescence and inhibits proliferation in tumor cells treated with sublethal doses of γ-irradiation. In mouse embryonic fibroblasts from NAC1 knockout mice, following infection with a Ras virus, NAC1-/- cells undergo significantly more senescence and are either nontransformed or less transformed in vitro and less tumorigenic in vivo when compared with NAC1+/+ cells. Furthermore, we show that the NAC1-caused senescence blunting is mediated by ΔNp63, which exerts its effect on senescence through p21, and that NAC1 activates transcription of ΔNp63 under stressful conditions. Our results not only reveal a previously unrecognized function of NAC1, the molecular pathway involved and its impact on pathogenesis of tumor initiation and development, but also identify a novel senescence regulator that may be exploited as a potential target for cancer prevention and treatment.

  10. Rescuing loading induced bone formation at senescence.

    Directory of Open Access Journals (Sweden)

    Sundar Srinivasan

    Full Text Available The increasing incidence of osteoporosis worldwide requires anabolic treatments that are safe, effective, and, critically, inexpensive given the prevailing overburdened health care systems. While vigorous skeletal loading is anabolic and holds promise, deficits in mechanotransduction accrued with age markedly diminish the efficacy of readily complied, exercise-based strategies to combat osteoporosis in the elderly. Our approach to explore and counteract these age-related deficits was guided by cellular signaling patterns across hierarchical scales and by the insight that cell responses initiated during transient, rare events hold potential to exert high-fidelity control over temporally and spatially distant tissue adaptation. Here, we present an agent-based model of real-time Ca(2+/NFAT signaling amongst bone cells that fully described periosteal bone formation induced by a wide variety of loading stimuli in young and aged animals. The model predicted age-related pathway alterations underlying the diminished bone formation at senescence, and hence identified critical deficits that were promising targets for therapy. Based upon model predictions, we implemented an in vivo intervention and show for the first time that supplementing mechanical stimuli with low-dose Cyclosporin A can completely rescue loading induced bone formation in the senescent skeleton. These pre-clinical data provide the rationale to consider this approved pharmaceutical alongside mild physical exercise as an inexpensive, yet potent therapy to augment bone mass in the elderly. Our analyses suggested that real-time cellular signaling strongly influences downstream bone adaptation to mechanical stimuli, and quantification of these otherwise inaccessible, transient events in silico yielded a novel intervention with clinical potential.

  11. REDOX REGULATION OF SIRT1 IN INFLAMMATION AND CELLULAR SENESCENCE

    Science.gov (United States)

    Hwang, Jae-woong; Yao, Hongwei; Caito, Samuel; Sundar, Isaac K.; Rahman, Irfan

    2013-01-01

    Sirtuin1 (SIRT1) regulates inflammation, aging (lifespan and healthspan), calorie restriction/energetics, mitochondrial biogenesis, stress resistance, cellular senescence, endothelial functions, apoptosis/autophagy, and circadian rhythms through deacetylation of transcription factors and histones. SIRT1 level and activity are decreased in chronic inflammatory conditions and aging where oxidative stress occurs. SIRT1 is regulated by a NAD+-dependent DNA repair enzyme poly(ADP-ribose)-polymerase-1 (PARP-1), and subsequent NAD+ depletion by oxidative stresses may have consequent effects on inflammatory and stress responses as well as cellular senescence. SIRT1 has been shown to undergo covalent oxidative modifications by cigarette smoke-derived oxidants/aldehydes, leading to post-translational modifications, inactivation, and protein degradation. Furthermore, oxidant/carbonyl stress-mediated reduction of SIRT1 leads to the loss of its control on acetylation of target proteins including p53, RelA/p65 and FOXO3, thereby enhancing the inflammatory, pro-senescent and apoptotic responses, as well as endothelial dysfunction. In this review, the mechanisms of cigarette smoke/oxidant-mediated redox post-translational modifications of SIRT1 and its role in PARP1, NF-κB activation, FOXO3 and eNOS regulation, as well as chromatin remodeling/histone modifications during inflammaging are discussed. Furthermore, we also discussed various novel ways to activate SIRT1 either directly or indirectly, which may have therapeutic potential in attenuating inflammation and premature senescence involved in chronic lung diseases. PMID:23542362

  12. Temporally distinct roles of ATM and ROS in genotoxic-stress-dependent induction and maintenance of cellular senescence.

    Science.gov (United States)

    Nair, Raji R; Bagheri, Meisam; Saini, Deepak Kumar

    2015-01-15

    Cells exposed to genotoxic stress induce cellular senescence through a DNA damage response (DDR) pathway regulated by ATM kinase and reactive oxygen species (ROS). Here, we show that the regulatory roles for ATM kinase and ROS differ during induction and maintenance of cellular senescence. Cells treated with different genotoxic agents were analyzed using specific pathway markers and inhibitors to determine that ATM kinase activation is directly proportional to the dose of the genotoxic stress and that senescence initiation is not dependent on ROS or the p53 status of cells. Cells in which ROS was quenched still activated ATM and initiated the DDR when insulted, and progressed normally to senescence. By contrast, maintenance of a viable senescent state required the presence of ROS as well as activated ATM. Inhibition or removal of either of the components caused cell death in senescent cells, through a deregulated ATM-ROS axis. Overall, our work demonstrates existence of an intricate temporal hierarchy between genotoxic stress, DDR and ROS in cellular senescence. Our model reports the existence of different stages of cellular senescence with distinct regulatory networks.

  13. The thorny path linking cellular senescence to organismalaging

    Energy Technology Data Exchange (ETDEWEB)

    Patil, Christopher K.; Mian, Saira; Campisi, Judith

    2005-08-09

    Half a century is fast approaching since Hayflick and colleagues formally described the limited ability of normal human cells to proliferate in culture (Hayflick and Moorhead, 1961). This finding--that normal somatic cells, in contrast to cancer cells, cannot divide indefinitely--challenged the prevailing idea that cells from mortal multicellular organisms were intrinsically ''immortal'' (Carrell, 1912). It also spawned two hypotheses, essential elements of which persist today. The first held that the restricted proliferation of normal cells, now termed cellular senescence, suppresses cancer (Hayflick, 1965; Sager, 1991; Campisi, 2001). The second hypothesis, as explained in the article by Lorenzini et al., suggested that the limited proliferation of cells in culture recapitulated aspects of organismal aging (Hayflick, 1965; Martin, 1993). How well have these hypotheses weathered the ensuing decades? Before answering this question, we first consider current insights into the causes and consequences of cellular senescence. Like Lorenzini et al., we limit our discussion to mammals. We also focus on fibroblasts, the cell type studied by Lorenzini et al., but consider other types as well. We suggest that replicative capacity in culture is not a straightforward assessment, and that it correlates poorly with both longevity and body mass. We speculate this is due to the malleable and variable nature of replicative capacity, which renders it an indirect metric of qualitative and quantitative differences among cells to undergo senescence, a response that directly alters cellular phenotype and might indirectly alter tissue structure and function.

  14. Aquatide Activation of SIRT1 Reduces Cellular Senescence through a SIRT1-FOXO1-Autophagy Axis.

    Science.gov (United States)

    Lim, Chae Jin; Lee, Yong-Moon; Kang, Seung Goo; Lim, Hyung W; Shin, Kyong-Oh; Jeong, Se Kyoo; Huh, Yang Hoon; Choi, Suin; Kor, Myungho; Seo, Ho Seong; Park, Byeong Deog; Park, Keedon; Ahn, Jeong Keun; Uchida, Yoshikazu; Park, Kyungho

    2017-09-01

    Ultraviolet (UV) irradiation is a relevant environment factor to induce cellular senescence and photoaging. Both autophagy- and silent information regulator T1 (SIRT1)-dependent pathways are critical cellular processes of not only maintaining normal cellular functions, but also protecting cellular senescence in skin exposed to UV irradiation. In the present studies, we investigated whether modulation of autophagy induction using a novel synthetic SIRT1 activator, heptasodium hexacarboxymethyl dipeptide-12 (named as Aquatide), suppresses the UVB irradiation-induced skin aging. Treatment with Aquatide directly activates SIRT1 and stimulates autophagy induction in cultured human dermal fibroblasts. Next, we found that Aquatide-mediated activation of SIRT1 increases autophagy induction via deacetylation of forkhead box class O (FOXO) 1. Finally, UVB irradiation-induced cellular senescence measured by SA-β-gal staining was significantly decreased in cells treated with Aquatide in parallel to occurring SIRT1 activation-dependent autophagy. Together, Aquatide modulates autophagy through SIRT1 activation, contributing to suppression of skin aging caused by UV irradiation.

  15. Interferon-γ induces senescence in normal human melanocytes.

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    Suiquan Wang

    Full Text Available BACKGROUND: Interferon-γ (IFN-γ plays an important role in the proceedings of vitiligo through recruiting lymphocytes to the lesional skin. However, the potential effects of IFN-γ on skin melanocytes and the subsequent contribution to the vitiligo pathogenesis are still unclear. OBJECTIVE: To investigate the effects of IFN-γ on viability and cellular functions of melanocytes. METHODS: Primary human melanocytes were treated with IFN-γ. Cell viability, apoptosis, cell cycle melanin content and intracellular reactive oxygen species (ROS level were measured. mRNA expression was examined by real-time PCR. The release of interleukin 6 (IL-6 and heat shock protein 70 (HSP-70 was monitored by ELISA. β-galactosidase staining was utilized to evaluate melanocyte senescence. RESULTS: Persistent IFN-γ treatment induced viability loss, apoptosis, cell cycle arrest and senescence in melanocytes. Melanocyte senescence was characterized as the changes in pigmentation and morphology, as well as the increase of β-galactosidase activity. Increase of p21Cip1/Waf1 protein was evident in melanocytes after IFN-γ treatment. IFN-γ induction of senescence was attenuated by siRNAs against p21, Janus kinase 2 (JAK2 or signal transducer and activator of transcription 1 (STAT1, but not by JAK1 siRNA nor by p53 inhibitor pifithrin-α. IFN-γ treatment increased the accumulation of intracellular ROS in melanocytes, while ROS scavenger N-acetyl cysteine (NAC effectively inhibited IFN-γ induced p21 expression and melanocyte senescence. IL-6 and HSP-70 release was significantly induced by IFN-γ treatment, which was largely inhibited by NAC. The increase of IL-6 and HSP-70 release could also be observed in senescent melanocytes. CONCLUSION: IFN-γ can induce senescence in melanocytes and consequently enhance their immuno-competency, leading to a vitiligo-prone milieu.

  16. Chromatin remodeling of human subtelomeres and TERRA promoters upon cellular senescence

    Science.gov (United States)

    Thijssen, Peter E.; Tobi, Elmar W.; Balog, Judit; Schouten, Suzanne G.; Kremer, Dennis; El Bouazzaoui, Fatiha; Henneman, Peter; Putter, Hein; Eline Slagboom, P.; Heijmans, Bastiaan T.; Van der Maarel, Silvère M.

    2013-01-01

    Subtelomeres are patchworks of evolutionary conserved sequence blocks and harbor the transcriptional start sites for telomere repeat containing RNAs (TERRA). Recent studies suggest that the interplay between telomeres and subtelomeric chromatin is required for maintaining telomere function. To further characterize chromatin remodeling of subtelomeres in relation to telomere shortening and cellular senescence, we systematically quantified histone modifications and DNA methylation at the subtelomeres of chromosomes 7q and 11q in primary human WI-38 fibroblasts. Upon senescence, both subtelomeres were characterized by a decrease in markers of constitutive heterochromatin, suggesting relative chromatin relaxation. However, we did not find increased levels of markers of euchromatin or derepression of the 7q VIPR2 gene. The repressed state of the subtelomeres was maintained upon senescence, which could be attributed to a rise in levels of facultative heterochromatin markers at both subtelomeres. While senescence-induced subtelomeric chromatin remodeling was similar for both chromosomes, chromatin remodeling at TERRA promoters displayed chromosome-specific patterns. At the 7q TERRA promoter, chromatin structure was co-regulated with the more proximal subtelomere. In contrast, the 11q TERRA promoter, which was previously shown to be bound by CCCTC-binding factor CTCF, displayed lower levels of markers of constitutive heterochromatin that did not change upon senescence, whereas levels of markers of facultative heterochromatin decreased upon senescence. In line with the chromatin state data, transcription of 11q TERRA but not 7q TERRA was detected. Our study provides a detailed description of human subtelomeric chromatin dynamics and shows distinct regulation of the TERRA promoters of 7q and 11q upon cellular senescence. PMID:23644601

  17. Redox regulation of SIRT1 in inflammation and cellular senescence.

    Science.gov (United States)

    Hwang, Jae-woong; Yao, Hongwei; Caito, Samuel; Sundar, Isaac K; Rahman, Irfan

    2013-08-01

    Sirtuin 1 (SIRT1) regulates inflammation, aging (life span and health span), calorie restriction/energetics, mitochondrial biogenesis, stress resistance, cellular senescence, endothelial functions, apoptosis/autophagy, and circadian rhythms through deacetylation of transcription factors and histones. SIRT1 level and activity are decreased in chronic inflammatory conditions and aging, in which oxidative stress occurs. SIRT1 is regulated by a NAD(+)-dependent DNA repair enzyme, poly(ADP-ribose) polymerase-1 (PARP1), and subsequent NAD(+) depletion by oxidative stress may have consequent effects on inflammatory and stress responses as well as cellular senescence. SIRT1 has been shown to undergo covalent oxidative modifications by cigarette smoke-derived oxidants/aldehydes, leading to posttranslational modifications, inactivation, and protein degradation. Furthermore, oxidant/carbonyl stress-mediated reduction of SIRT1 leads to the loss of its control on acetylation of target proteins including p53, RelA/p65, and FOXO3, thereby enhancing the inflammatory, prosenescent, and apoptotic responses, as well as endothelial dysfunction. In this review, the mechanisms of cigarette smoke/oxidant-mediated redox posttranslational modifications of SIRT1 and its roles in PARP1 and NF-κB activation, and FOXO3 and eNOS regulation, as well as chromatin remodeling/histone modifications during inflammaging, are discussed. Furthermore, we have also discussed various novel ways to activate SIRT1 either directly or indirectly, which may have therapeutic potential in attenuating inflammation and premature senescence involved in chronic lung diseases.

  18. NETRIN-4 protects glioblastoma cells FROM temozolomide induced senescence.

    Directory of Open Access Journals (Sweden)

    Li Li

    Full Text Available Glioblastoma multiforme is the most common primary tumor of the central nervous system. The drug temozolomide (TMZ prolongs lifespan in many glioblastoma patients. The sensitivity of glioblastoma cells to TMZ is interfered by many factors, such as the expression of O-6-methylguanine-DNA methyltransferase (MGMT and activation of AKT signaling. We have recently identified the interaction between netrin-4 (NTN4 and integrin beta-4 (ITGB4, which promotes glioblastoma cell proliferation via activating AKT-mTOR signaling pathway. In the current work we have explored the effect of NTN4/ITGB4 interaction on TMZ induced glioblastoma cell senescence. We report here that the suppression of either ITGB4 or NTN4 in glioblastoma cell lines significantly enhances cellular senescence. The sensitivity of GBM cells to TMZ was primarily determined by the expression of MGMT. To omit the effect of MGMT, we concentrated on the cell lines devoid of expression of MGMT. NTN4 partially inhibited TMZ induced cell senescence and rescued AKT from dephosphorylation in U251MG cells, a cell line bearing decent levels of ITGB4. However, addition of exogenous NTN4 displayed no significant effect on TMZ induced senescence rescue or AKT activation in U87MG cells, which expressed ITGB4 at low levels. Furthermore, overexpression of ITGB4 combined with exogenous NTN4 significantly attenuated U87MG cell senescence induced by TMZ. These data suggest that NTN4 protects glioblastoma cells from TMZ induced senescence, probably via rescuing TMZ triggered ITGB4 dependent AKT dephosphorylation. This suggests that interfering the interaction between NTN4 and ITGB4 or concomitant use of the inhibitors of the AKT pathway may improve the therapeutic efficiency of TMZ.

  19. NETRIN-4 protects glioblastoma cells FROM temozolomide induced senescence.

    Science.gov (United States)

    Li, Li; Hu, Yizhou; Ylivinkka, Irene; Li, Huini; Chen, Ping; Keski-Oja, Jorma; Hyytiäinen, Marko

    2013-01-01

    Glioblastoma multiforme is the most common primary tumor of the central nervous system. The drug temozolomide (TMZ) prolongs lifespan in many glioblastoma patients. The sensitivity of glioblastoma cells to TMZ is interfered by many factors, such as the expression of O-6-methylguanine-DNA methyltransferase (MGMT) and activation of AKT signaling. We have recently identified the interaction between netrin-4 (NTN4) and integrin beta-4 (ITGB4), which promotes glioblastoma cell proliferation via activating AKT-mTOR signaling pathway. In the current work we have explored the effect of NTN4/ITGB4 interaction on TMZ induced glioblastoma cell senescence. We report here that the suppression of either ITGB4 or NTN4 in glioblastoma cell lines significantly enhances cellular senescence. The sensitivity of GBM cells to TMZ was primarily determined by the expression of MGMT. To omit the effect of MGMT, we concentrated on the cell lines devoid of expression of MGMT. NTN4 partially inhibited TMZ induced cell senescence and rescued AKT from dephosphorylation in U251MG cells, a cell line bearing decent levels of ITGB4. However, addition of exogenous NTN4 displayed no significant effect on TMZ induced senescence rescue or AKT activation in U87MG cells, which expressed ITGB4 at low levels. Furthermore, overexpression of ITGB4 combined with exogenous NTN4 significantly attenuated U87MG cell senescence induced by TMZ. These data suggest that NTN4 protects glioblastoma cells from TMZ induced senescence, probably via rescuing TMZ triggered ITGB4 dependent AKT dephosphorylation. This suggests that interfering the interaction between NTN4 and ITGB4 or concomitant use of the inhibitors of the AKT pathway may improve the therapeutic efficiency of TMZ.

  20. Combinatorial effects of continuous protein synthesis, ERK-signaling, and reactive oxygen species on induction of cellular senescence.

    Science.gov (United States)

    Takauji, Yuki; En, Atsuki; Miki, Kensuke; Ayusawa, Dai; Fujii, Michihiko

    2016-07-15

    Mammalian cells, when treated with sub-lethal doses of genotoxic stresses, slow down DNA synthesis but continue protein synthesis. Thus, these cells show an accumulation of proteins and undergo unbalanced growth. In the previous studies, we have shown that HeLa cells treated with excess thymidine or camptothecin undergo unbalanced growth, and prolonged unbalanced growth causes induction of cellular senescence, which is suppressed by restriction of protein synthesis or inhibition of ERK-signaling. In this study, we found that restriction of protein synthesis, inhibition of ERK-signaling, and elimination of reactive oxygen species showed a combinatorial effect on suppression of cellular senescence induced by excess thymidine or camptothecin. Of these, restriction of protein synthesis most effectively suppressed cellular senescence. Importantly, a similar combinatorial effect was observed in replicative senescence in normal human diploid fibroblasts. Our findings suggested that various stresses were cumulatively involved in cellular senescence, and suppression of cellular senescence was improved by combining the treatments that reduce the stresses.

  1. Accelerated cellular senescence phenotype of GAPDH-depleted human lung carcinoma cells

    Energy Technology Data Exchange (ETDEWEB)

    Phadke, Manali; Krynetskaia, Natalia [Temple University School of Pharmacy, Philadelphia, PA 19140 (United States); Mishra, Anurag [Jayne Haines Center for Pharmacogenomics, Temple University School of Pharmacy, Philadelphia, PA 19140 (United States); Krynetskiy, Evgeny, E-mail: ekrynets@temple.edu [Temple University School of Pharmacy, Philadelphia, PA 19140 (United States); Jayne Haines Center for Pharmacogenomics, Temple University School of Pharmacy, Philadelphia, PA 19140 (United States)

    2011-07-29

    Highlights: {yields} We examined the effect of glyceraldehyde 3-phosphate (GAPDH) depletion on proliferation of human carcinoma A549 cells. {yields} GAPDH depletion induces accelerated senescence in tumor cells via AMPK network, in the absence of DNA damage. {yields} Metabolic and genetic rescue experiments indicate that GAPDH has regulatory functions linking energy metabolism and cell cycle. {yields} Induction of senescence in LKB1-deficient lung cancer cells via GAPDH depletion suggests a novel strategy to control tumor cell proliferation. -- Abstract: Glyceraldehyde 3-phosphate dehydrogenase (GAPDH) is a pivotal glycolytic enzyme, and a signaling molecule which acts at the interface between stress factors and the cellular apoptotic machinery. Earlier, we found that knockdown of GAPDH in human carcinoma cell lines resulted in cell proliferation arrest and chemoresistance to S phase-specific cytotoxic agents. To elucidate the mechanism by which GAPDH depletion arrests cell proliferation, we examined the effect of GAPDH knockdown on human carcinoma cells A549. Our results show that GAPDH-depleted cells establish senescence phenotype, as revealed by proliferation arrest, changes in morphology, SA-{beta}-galactosidase staining, and more than 2-fold up-regulation of senescence-associated genes DEC1 and GLB1. Accelerated senescence following GAPDH depletion results from compromised glycolysis and energy crisis leading to the sustained AMPK activation via phosphorylation of {alpha} subunit at Thr172. Our findings demonstrate that GAPDH depletion switches human tumor cells to senescent phenotype via AMPK network, in the absence of DNA damage. Rescue experiments using metabolic and genetic models confirmed that GAPDH has important regulatory functions linking the energy metabolism and the cell cycle networks. Induction of senescence in LKB1-deficient non-small cell lung cancer cells via GAPDH depletion suggests a novel strategy to control tumor cell proliferation.

  2. Simvastatin suppresses breast cancer cell proliferation induced by senescent cells

    NARCIS (Netherlands)

    Liu, Su; Uppal, Harpreet; Demaria, Marco; Desprez, Pierre-Yves; Campisi, Judith; Kapahi, Pankaj

    2015-01-01

    Cellular senescence suppresses cancer by preventing the proliferation of damaged cells, but senescent cells can also promote cancer though the pro-inflammatory senescence-associated secretory phenotype (SASP). Simvastatin, an HMG-coA reductase inhibitor, is known to attenuate inflammation and preven

  3. Mitochondrial DNA damage induces apoptosis in senescent cells

    NARCIS (Netherlands)

    Laberge, R-M; Adler, D; DeMaria, M; Mechtouf, N; Teachenor, R; Cardin, G B; Desprez, P-Y; Campisi, J; Rodier, F

    2013-01-01

    Senescence is a cellular response to damage and stress. The senescence response prevents cancer by suppressing the proliferation of cells with a compromised genome and contributes to optimal wound healing in normal tissues. Persistent senescent cells are also thought to drive aging and age-associate

  4. Chronic treatment with N-acetyl-cystein delays cellular senescence in endothelial cells isolated from a subgroup of atherosclerotic patients.

    Science.gov (United States)

    Voghel, Guillaume; Thorin-Trescases, Nathalie; Farhat, Nada; Mamarbachi, Aida M; Villeneuve, Louis; Fortier, Annik; Perrault, Louis P; Carrier, Michel; Thorin, Eric

    2008-05-01

    Endothelial senescence may contribute to the pathogenesis of age-related vascular disorders. Furthermore, chronic exposure to risk factors for cardiovascular disease (CVD) accelerates the effects of chronological aging by generating stress-dependent damages, including oxidative stress, therefore promoting stress-induced premature senescence. Our objective was to determine whether a chronic treatment with an antioxidant (N-acetyl-cystein, NAC) could delay senescence of endothelial cells (EC) isolated and cultured from arterial segments of patients with severe coronary artery disease. If EC were considered as one population (n=26), chronic NAC treatment slightly shortened telomere attrition rate associated with senescence but did not significantly delay the onset of endothelial senescence. However, in a subgroup of NAC-treated EC (n=15) cellular senescence was significantly delayed, NAC decreased lipid peroxidation (HNE), activated the catalytic subunit of telomerase (hTERT) and inhibited telomere attrition. In contrast, in another subgroup of EC (n=11) characterized by initial short telomeres, no effect of NAC on HNE and high levels of DNA damages, the antioxidant was not beneficial on senescence, suggesting an irreversible stress-dependent damage. In conclusion, chronic exposure to NAC can delay senescence of diseased EC via hTERT activation and transient telomere stabilization, unless oxidative stress-associated cell damage has become irreversible.

  5. Failure of cell cleavage induces senescence in tetraploid primary cells.

    Science.gov (United States)

    Panopoulos, Andreas; Pacios-Bras, Cristina; Choi, Justin; Yenjerla, Mythili; Sussman, Mark A; Fotedar, Rati; Margolis, Robert L

    2014-10-15

    Tetraploidy can arise from various mitotic or cleavage defects in mammalian cells, and inheritance of multiple centrosomes induces aneuploidy when tetraploid cells continue to cycle. Arrest of the tetraploid cell cycle is therefore potentially a critical cellular control. We report here that primary rat embryo fibroblasts (REF52) and human foreskin fibroblasts become senescent in tetraploid G1 after drug- or small interfering RNA (siRNA)-induced failure of cell cleavage. In contrast, T-antigen-transformed REF52 and p53+/+ HCT116 tumor cells rapidly become aneuploid by continuing to cycle after cleavage failure. Tetraploid primary cells quickly become quiescent, as determined by loss of the Ki-67 proliferation marker and of the fluorescent ubiquitination-based cell cycle indicator/late cell cycle marker geminin. Arrest is not due to DNA damage, as the γ-H2AX DNA damage marker remains at control levels after tetraploidy induction. Arrested tetraploid cells finally become senescent, as determined by SA-β-galactosidase activity. Tetraploid arrest is dependent on p16INK4a expression, as siRNA suppression of p16INK4a bypasses tetraploid arrest, permitting primary cells to become aneuploid. We conclude that tetraploid primary cells can become senescent without DNA damage and that induction of senescence is critical to tetraploidy arrest.

  6. Autophagy promotes radiation-induced senescence but inhibits bystander effects in human breast cancer cells.

    Science.gov (United States)

    Huang, Yao-Huei; Yang, Pei-Ming; Chuah, Qiu-Yu; Lee, Yi-Jang; Hsieh, Yi-Fen; Peng, Chih-Wen; Chiu, Shu-Jun

    2014-07-01

    Ionizing radiation induces cellular senescence to suppress cancer cell proliferation. However, it also induces deleterious bystander effects in the unirradiated neighboring cells through the release of senescence-associated secretory phenotypes (SASPs) that promote tumor progression. Although autophagy has been reported to promote senescence, its role is still unclear. We previously showed that radiation induces senescence in PTTG1-depleted cancer cells. In this study, we found that autophagy was required for the radiation-induced senescence in PTTG1-depleted breast cancer cells. Inhibition of autophagy caused the cells to switch from radiation-induced senescence to apoptosis. Senescent cancer cells exerted bystander effects by promoting the invasion and migration of unirradiated cells through the release of CSF2 and the subsequently activation of the JAK2-STAT3 and AKT pathways. However, the radiation-induced bystander effects were correlated with the inhibition of endogenous autophagy in bystander cells, which also resulted from the activation of the CSF2-JAK2 pathway. The induction of autophagy by rapamycin reduced the radiation-induced bystander effects. This study reveals, for the first time, the dual role of autophagy in radiation-induced senescence and bystander effects.

  7. Mortalin sensitizes human cancer cells to MKT-077-induced senescence.

    Science.gov (United States)

    Deocaris, Custer C; Widodo, Nashi; Shrestha, Bhupal G; Kaur, Kamaljit; Ohtaka, Manami; Yamasaki, Kazuhiko; Kaul, Sunil C; Wadhwa, Renu

    2007-07-18

    Mortalin is a chaperone protein that functions in many cellular processes such as mitochondrial biogenesis, intracellular trafficking, cell proliferation and signaling. Its upregulation in many human cancers makes it a candidate target for therapeutic intervention by small molecule drugs. In continuation to our earlier studies showing mortalin as a cellular target of MKT-077, a mitochondrion-seeking delocalized cationic dye that causes selective death of cancer cells, in this work, we report that MKT-077 binds to the nucleotide-binding domain of mortalin, causes tertiary structural changes in the protein, inactivates its chaperone function, and induces senescence in human tumor cell lines. Interestingly, in tumor cells with elevated level of mortalin expression, fairly low drug doses were sufficient to induce senescence. Guided by molecular screening for mortalin in tumor cells, our results led to the idea that working at low doses of the drug could be an alternative senescence-inducing cancer therapeutic strategy that could, in theory, avoid renal toxicities responsible for the abortion of MKT-077 clinical trials. Our work may likely translate to a re-appraisal of the therapeutic benefits of low doses of several classes of anti-tumor drugs, even of those that had been discontinued due to adverse effects.

  8. Beryllium induces premature senescence in human fibroblasts.

    Science.gov (United States)

    Coates, Shannon S A; Lehnert, Bruce E; Sharma, Sunil; Kindell, Susan M; Gary, Ronald K

    2007-07-01

    After cells have completed a sufficient number of cell divisions, they exit the cell cycle and enter replicative senescence. Here, we report that beryllium causes proliferation arrest with premature expression of the principal markers of senescence. After young presenescent human fibroblasts were treated with 3 microM BeSO(4) for 24 h, p21 cyclin-dependent kinase inhibitor mRNA increased by >200%. Longer periods of exposure caused mRNA and protein levels to increase for both p21 and p16(Ink4a), a senescence regulator that prevents pRb-mediated cell cycle progression. BeSO(4) also caused dose-dependent induction of senescence-associated beta-galactosidase activity (SA-beta-gal). Untreated cells had 48 relative fluorescence units (RFU)/microg/h of SA-beta-gal, whereas 3 microM BeSO(4) caused activity to increase to 84 RFU/microg/h. In chromatin immunoprecipitation experiments, BeSO(4) caused p53 protein to associate with its DNA binding site in the promoter region of the p21 gene, indicating that p53 transcriptional activity is responsible for the large increase in p21 mRNA elicited by beryllium. Forced expression of human telomerase reverse transcriptase (hTERT) rendered HFL-1 cells incapable of normal replicative senescence. However, there was no difference in the responsiveness of normal HFL-1 fibroblasts (IC(50) = 1.9 microM) and hTERT-immortalized cells (IC(50) = 1.7 microM) to BeSO(4) in a 9-day proliferation assay. The effects of beryllium resemble those of histone deacetylase-inhibiting drugs, which also cause large increases in p21. However, beryllium produced no changes in histone acetylation, suggesting that Be(2+) acts as a novel and potent pharmacological inducer of premature senescence.

  9. Conserved and novel functions of programmed cellular senescence during vertebrate development

    Science.gov (United States)

    Davaapil, Hongorzul; Brockes, Jeremy P.

    2017-01-01

    Cellular senescence, a form of stable cell cycle arrest that is traditionally associated with tumour suppression, has been recently found to occur during mammalian development. Here, we show that cell senescence is an intrinsic part of the developmental programme in amphibians. Programmed senescence occurs in specific structures during defined time windows during amphibian development. It contributes to the physiological degeneration of the amphibian pronephros and to the development of the cement gland and oral cavity. In both contexts, senescence depends on TGFβ but is independent of ERK/MAPK activation. Furthermore, elimination of senescent cells through temporary TGFβ inhibition leads to developmental defects. Our findings uncover conserved and new roles of senescence in vertebrate organogenesis and support the view that cellular senescence may have arisen in evolution as a developmental mechanism. PMID:27888193

  10. The cell cycle regulator protein P16 and the cellular senescence of dental follicle cells.

    Science.gov (United States)

    Morsczeck, Christian; Hullmann, Markus; Reck, Anja; Reichert, Torsten E

    2017-08-02

    Cellular senescence is a restricting factor for regenerative therapies with somatic stem cells. We showed previously that the onset of cellular senescence inhibits the osteogenic differentiation in stem cells of the dental follicle (DFCs), although the mechanism remains elusive. Two different pathways are involved in the induction of the cellular senescence, which are driven either by the cell cycle protein P21 or by the cell cycle protein P16. In this study, we investigated the expression of cell cycle proteins in DFCs after the induction of cellular senescence. The induction of cellular senescence was proved by an increased expression of β-galactosidase and an increased population doubling time after a prolonged cell culture. Cellular senescence regulated the expression of cell cycle proteins. The expression of cell cycle protein P16 was up-regulated, which correlates with the induction of cellular senescence markers in DFCs. However, the expression of cyclin-dependent kinases (CDK)2 and 4 and the expression of the cell cycle protein P21 were successively decreased in DFCs. In conclusion, our data suggest that a P16-dependent pathway drives the induction of cellular senescence in DFCs.

  11. JMJD2A Promotes Cellular Transformation by Blocking Cellular Senescence through Transcriptional Repression of the Tumor Suppressor CHD5

    Directory of Open Access Journals (Sweden)

    Frédérick A. Mallette

    2012-11-01

    Full Text Available Senescence is a cellular response preventing tumorigenesis. The Ras oncogene is frequently activated or mutated in human cancers, but Ras activation is insufficient to transform primary cells. In a search for cooperating oncogenes, we identify the lysine demethylase JMJD2A/KDM4A. We show that JMJD2A functions as a negative regulator of Ras-induced senescence and collaborates with oncogenic Ras to promote cellular transformation by negatively regulating the p53 pathway. We find CHD5, a known tumor suppressor regulating p53 activity, as a target of JMJD2A. The expression of JMJD2A inhibits Ras-mediated CHD5 induction leading to a reduced activity of the p53 pathway. In addition, we show that JMJD2A is overexpressed in mouse and human lung cancers. Depletion of JMJD2A in the human lung cancer cell line A549 bearing an activated K-Ras allele triggers senescence. We propose that JMJD2A is an oncogene that represents a target for Ras-expressing tumors.

  12. The inhibitory mechanism of Cordyceps sinensis on cigarette smoke extract-induced senescence in human bronchial epithelial cells.

    Science.gov (United States)

    Liu, Ailing; Wu, Jinxiang; Li, Aijun; Bi, Wenxiang; Liu, Tian; Cao, Liuzhao; Liu, Yahui; Dong, Liang

    2016-01-01

    Cellular senescence is a state of irreversible growth arrest induced either by telomere shortening (replicative senescence) or stress. The bronchial epithelial cell is often injured by inhaled toxic substances, such as cigarette smoke. In the present study, we investigated whether exposure to cigarette smoke extract (CSE) induces senescence of bronchial epithelial cells; and Cordyceps sinensis mechanism of inhibition of CSE-induced cellular senescence. Human bronchial epithelial cells (16HBE cells) cultured in vitro were treated with CSE and/or C. sinensis. p16, p21, and senescence-associated-galactosidase activity were used to detect cellular senescence with immunofluorescence, quantitative polymerase chain reaction, and Western blotting. Reactive oxygen species (ROS), PI3K/AKT/mTOR and their phosphorylated proteins were examined to testify the activation of signaling pathway by ROS fluorescent staining and Western blotting. Then, inhibitors of ROS and PI3K were used to further confirm the function of this pathway. Cellular senescence was upregulated by CSE treatment, and C. sinensis can decrease CSE-induced cellular senescence. Activation of ROS/PI3K/AKT/mTOR signaling pathway was enhanced by CSE treatment, and decreased when C. sinensis was added. Blocking ROS/PI3K/AKT/mTOR signaling pathway can attenuate CSE-induced cellular senescence. CSE can induce cellular senescence in human bronchial epithelial cells, and ROS/PI3K/AKT/mTOR signaling pathway may play an important role in this process. C. sinensis can inhibit the CSE-induced senescence.

  13. From Ancient Pathways to Aging Cells-Connecting Metabolism and Cellular Senescence.

    Science.gov (United States)

    Wiley, Christopher D; Campisi, Judith

    2016-06-14

    Cellular senescence is a complex stress response that permanently arrests the proliferation of cells at risk for oncogenic transformation. However, senescent cells can also drive phenotypes associated with aging. Although the senescence-associated growth arrest prevents the development of cancer, and the metabolism of cancer cells has been studied in depth, the metabolic causes and consequences of cellular senescence were largely unexplored until recently. New findings reveal key roles for several aspects of cellular metabolism in the establishment and control of senescent phenotypes. These discoveries have important implications for both cancer and aging. In this review, we highlight some of the recent links between metabolism and phenotypes that are commonly associated with senescent cells.

  14. Mitochondrial DNA deletion and impairment of mitochondrial biogenesis by reactive oxygen species in ionizing radiation-induced premature senescence

    Energy Technology Data Exchange (ETDEWEB)

    Eom, Hyeon Soo; Jung, U Hee; Jo, Sung Kee [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2011-10-15

    The aim of this study was to determine whether an increase of ROS level in cellular senescence induced by IR could mediate mtDNA deletion via impairment of mitochondria biogenesis in IMR-90 human lung fibroblast cells. Our results showed that IR induced cellular senescence, intracellular ROS, and mtDNA deletion, and in particular, suppressed the expression of mitochondrial biogenesis genes (NRF-1, TFAM). Furthermore, these IR-induced events were abolished using a potent antioxidant, NAC, which suggests that ROS is a key cause of mtDNA deletion in IR-induced cellular senescence, and that the alteration of mitochondrial biogenesis may mediate these processes

  15. Human endothelial senescence induced by IL-1α in vitro

    Institute of Scientific and Technical Information of China (English)

    YAO Aiyu; ZHOU Jianjun; LIU Yabing; FENG Meifu; ZHOU Rouli

    2004-01-01

    Interleukin 1(IL-1) is an important proinflammatory cytokine that causes pleiotropic effects. Vascular endothelial cells stimulated by IL-1α can lead to the inflammatory response. Reactive oxygen species (ROS) are also generated at the site of inflammation and serve as an important factor against foreign invader. Here we report that long-term stimulation of human vein endothelial cells with IL-1α can accelerate their senescence associated with β-galactosidase activity. The flow cytometric analyses showed that most of the induced cells entered G0-G1 phase. DNA damage was more severe in senescent cells by comet assay. The induced cells by IL-1α had higher levels of ROS and malonyldialdehyde (MDA), lower activity of antioxidant enzymes and lower capacity of total antioxidant systems than control, which led to cell damage and cell degeneration, that is to say, which contributed to cellular senescence. Our results gave a direct proof to a new hypothesis-"the inflammation hypothesis of aging" on cellular level, and also provided a basis for the study on anti-aging and aging-related diseases.

  16. Arctigenin induced gallbladder cancer senescence through modulating epidermal growth factor receptor pathway.

    Science.gov (United States)

    Zhang, Mingdi; Cai, Shizhong; Zuo, Bin; Gong, Wei; Tang, Zhaohui; Zhou, Di; Weng, Mingzhe; Qin, Yiyu; Wang, Shouhua; Liu, Jun; Ma, Fei; Quan, Zhiwei

    2017-05-01

    Gallbladder cancer has poor prognosis and limited therapeutic options. Arctigenin, a representative dibenzylbutyrolactone lignan, occurs in a variety of plants. However, the molecular mechanisms involved in the antitumor effect of arctigenin on gallbladder cancer have not been fully elucidated. The expression levels of epidermal growth factor receptor were examined in 100 matched pairs of gallbladder cancer tissues. A positive correlation between high epidermal growth factor receptor expression levels and poor prognosis was observed in gallbladder cancer tissues. Pharmacological inhibition or inhibition via RNA interference of epidermal growth factor receptor induced cellular senescence in gallbladder cancer cells. The antitumor effect of arctigenin on gallbladder cancer cells was primarily achieved by inducing cellular senescence. In gallbladder cancer cells treated with arctigenin, the expression level of epidermal growth factor receptor significantly decreased. The analysis of the activity of the kinases downstream of epidermal growth factor receptor revealed that the RAF-MEK-ERK signaling pathway was significantly inhibited. Furthermore, the cellular senescence induced by arctigenin could be reverted by pcDNA-epidermal growth factor receptor. Arctigenin also potently inhibited the growth of tumor xenografts, which was accompanied by the downregulation of epidermal growth factor receptor and induction of senescence. This study demonstrates arctigenin could induce cellular senescence in gallbladder cancer through the modulation of epidermal growth factor receptor pathway. These data identify epidermal growth factor receptor as a key regulator in arctigenin-induced gallbladder cancer senescence.

  17. Cellular senescence regulated by SWI/SNF complex subunits through p53/p21 and p16/pRB pathway.

    Science.gov (United States)

    He, Ling; Chen, Ying; Feng, Jianguo; Sun, Weichao; Li, Shun; Ou, Mengting; Tang, Liling

    2017-09-01

    SWI/SNF complex is an evolutionarily well-conserved chromatin-remodeling complex, which is implicated in the nucleosomes removing or sliding, impacting on the DNA repair, replication and genes expression regulation. The SWI/SNF complex consists up to 12 protein subunits. The catalytic subunits are BRG1 or BRM, which are exclusive ATPase subunits. BRG1 has been reported to play an important role in cellular senescence. However, The function of non-catalytic subunits involved in cellular senescence is rarely investigated. Therefore, we focused on the senescence regulation roles of SWI/SNF non-catalytic subunits in cellular senescent model induced by H2O2. H2O2 treatment was used to induce cellular senescence models in vitro. Screening the candidate subunits involved in this process by comparing the expression levels of SWI/SNF subunits with/without H2O2 treatment. Over-expression and knockdown the candidate subunits were utilized to investigate the functions and mechanism of the subunits involved in senescence regulation. The expressions of BAF57, BAF60a and SNF5 were changed significantly after H2O2 treatment. Overexpression of the three subunits separately induced cell growth arrest in both HaCaT and GLL19 cells, while knockdown of the subunits separately eased the senescence induced by H2O2 treatment. Results further showed that BAF57, BAF60a and SNF5 regulated cellular senescence via both p53/p21 and p16/pRB pathways, and the three subunits all had a directly interaction with p53. These results indicated that BAF57, BAF60a and SNF5 might act as novel pro-senescence factors in both normal and tumor human skin cells. Therefore, inhibiting expression of the three factors might delay the cellular senescence process. Copyright © 2017 Elsevier Ltd. All rights reserved.

  18. The Yin-Yang of DNA Damage Response: Roles in Tumorigenesis and Cellular Senescence

    Directory of Open Access Journals (Sweden)

    Sang Soo Kim

    2013-01-01

    Full Text Available Senescent cells are relatively stable, lacking proliferation capacity yet retaining metabolic activity. In contrast, cancer cells are rather invasive and devastating, with uncontrolled proliferative capacity and resistance to cell death signals. Although tumorigenesis and cellular senescence are seemingly opposite pathological events, they are actually driven by a unified mechanism: DNA damage. Integrity of the DNA damage response (DDR network can impose a tumorigenesis barrier by navigating abnormal cells to cellular senescence. Compromise of DDR, possibly due to the inactivation of DDR components, may prevent cellular senescence but at the expense of tumor formation. Here we provide an overview of the fundamental role of DDR in tumorigenesis and cellular senescence, under the light of the Yin-Yang concept of Chinese philosophy. Emphasis is placed on discussing DDR outcome in the light of in vivo models. This information is critical as it can help make better decisions for clinical treatments of cancer patients.

  19. Selenoprotein H suppresses cellular senescence through genome maintenance and redox regulation.

    Science.gov (United States)

    Wu, Ryan T Y; Cao, Lei; Chen, Benjamin P C; Cheng, Wen-Hsing

    2014-12-05

    Oxidative stress and persistent DNA damage response contribute to cellular senescence, a degeneration process critically involving ataxia telangiectasia-mutated (ATM) and p53. Selenoprotein H (SelH), a nuclear selenoprotein, is proposed to carry redox and transactivation domains. To determine the role of SelH in genome maintenance, shRNA knockdown was employed in human normal and immortalized cell lines. SelH shRNA MRC-5 diploid fibroblasts under ambient O2 displayed a distinct profile of senescence including β-galactosidase expression, autofluorescence, growth inhibition, and ATM pathway activation. Such senescence phenotypes were alleviated in the presence of ATM kinase inhibitors, by p53 shRNA knockdown, or by maintaining the cells under 3% O2. During the course of 5-day recovery, the induction of phospho-ATM on Ser-1981 and γH2AX by H2O2 treatment (20 μm) subsided in scrambled shRNA but exacerbated in SelH shRNA MRC-5 cells. Results from clonogenic assays demonstrated hypersensitivity of SelH shRNA HeLa cells to paraquat and H2O2, but not to hydroxyurea, neocarzinostatin, or camptothecin. While SelH mRNA expression was induced by H2O2 treatment, SelH-GFP did not mobilize to sites of oxidative DNA damage. The glutathione level was lower in SelH shRNA than scrambled shRNA HeLa cells, and the H2O2-induced cell death was rescued in the presence of N-acetylcysteine, a glutathione precursor. Altogether, SelH protects against cellular senescence to oxidative stress through a genome maintenance pathway involving ATM and p53.

  20. Autophagy and cellular senescence mediated by Sox2 suppress malignancy of cancer cells.

    Directory of Open Access Journals (Sweden)

    Yong-Yeon Cho

    Full Text Available Autophagy is a critical cellular process required for maintaining cellular homeostasis in health and disease states, but the molecular mechanisms and impact of autophagy on cancer is not fully understood. Here, we found that Sox2, a key transcription factor in the regulation of the "stemness" of embryonic stem cells and induced-pluripotent stem cells, strongly induced autophagic phenomena, including intracellular vacuole formation and lysosomal activation in colon cancer cells. The activation occurred through Sox2-mediated ATG10 gene expression and resulted in the inhibition of cell proliferation and anchorage-independent colony growth ex vivo and tumor growth in vivo. Further, we found that Sox2-induced-autophagy enhanced cellular senescence by up-regulating tumor suppressors or senescence factors, including p16(INK4a, p21 and phosphorylated p53 (Ser15. Notably, knockdown of ATG10 in Sox2-expressing colon cancer cells restored cancer cell properties. Taken together, our results demonstrated that regulation of autophagy mediated by Sox2 is a mechanism-driven novel strategy to treat human colon cancers.

  1. Novel Approach to Bile Duct Damage in Primary Biliary Cirrhosis: Participation of Cellular Senescence and Autophagy

    Directory of Open Access Journals (Sweden)

    Motoko Sasaki

    2012-01-01

    Full Text Available Primary biliary cirrhosis (PBC is characterized by antimitochondrial autoantibodies (AMAs in patients' sera and histologically by chronic nonsuppurative destructive cholangitis in small bile ducts, eventually followed by extensive bile duct loss and biliary cirrhosis. The autoimmune-mediated pathogenesis of bile duct lesions, including the significance of AMAs, triggers of the autoimmune process, and so on remain unclear. We have reported that cellular senescence in biliary epithelial cells (BECs may be involved in bile duct lesions and that autophagy may precede the process of biliary epithelial senescence in PBC. Interestingly, BECs in damaged bile ducts show characteristicsof cellular senescence and autophagy in PBC. A suspected causative factor of biliary epithelial senescence is oxidative stress. Furthermore, senescent BECs may modulate the microenvironment around bile ducts by expressing various chemokines and cytokines called senescence-associated secretory phenotypes and contribute to the pathogenesis in PBC.

  2. Senescence-associated heterochromatin foci are dispensable for cellular senescence, occur in a cell type- and insult-dependent manner and follow expression of p16

    National Research Council Canada - National Science Library

    Kosar, Martin; Bartkova, Jirina; Hubackova, Sona; Hodny, Zdenek; Lukas, Jiri; Bartek, Jiri

    2011-01-01

    Cellular senescence, an irreversible proliferation arrest evoked by stresses such as oncogene activation, telomere dysfunction, or diverse genotoxic insults, has been implicated in tumor suppression and aging...

  3. Protective Effect of Garlic on Cellular Senescence in UVB-Exposed HaCaT Human Keratinocytes.

    Science.gov (United States)

    Kim, Hye Kyung

    2016-07-29

    Ultraviolet (UV) irradiation generates reactive oxygen species (ROS) in the cells, which induces the cellular senescence and photoaging. The present study investigated the protective effects of garlic on photo-damage and cellular senescence in UVB-exposed human keratinocytes, HaCaT cells. An in vitro cell free system was used to examine the scavenging activity of 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radicals and nitric oxide (NO). The effect of garlic extract on ROS formation, MMP-1 protein and mRNA expressions, cytokines such as interleukin (IL)-1β and IL-6, senescence associated-β-galactosidase (SA-β-gal) activity, and silent information regulator T1 (SIRT1) activity were determined in UVB-irradiated HaCaT cells. Garlic exhibited strong DPPH radical and NO scavenging activity in cell free system exhibiting IC50 values of 2.50 mg/mL and 4.38 mg/mL, respectively. Garlic pretreatment attenuated the production of UVB-induced intracellular ROS. MMP-1 level, which has been known to be induced by ROS, was dramatically elevated by UVB irradiation, and UVB-induced MMP-1 mRNA and protein expressions were significantly reduced by garlic treatment (50 µg/mL) comparable to those of UV-unexposed control cells. UV-induced pro-inflammatory cytokine productions (IL-6 and IL-1β) were significantly inhibited by pretreatment with garlic in a dose-dependent manner. SA-β-gal activity, a classical biomarker of cellular senescence, and SIRT1 activity, which has attracted attention as an anti-aging factor in recent years, were ameliorated by garlic treatment in UV-irradiated HaCaT cells. The present study provides the first evidence of garlic inhibiting UVB-induced photoaging as a result of augmentation of cellular senescence in HaCaT human keratinocytes.

  4. Cellular senescence in aging and age-related disease: from mechanisms to therapy

    NARCIS (Netherlands)

    Childs, B.G.; Durik, M.; Baker, D.J.; Deursen, J.M.A. van

    2015-01-01

    Cellular senescence, a process that imposes permanent proliferative arrest on cells in response to various stressors, has emerged as a potentially important contributor to aging and age-related disease, and it is an attractive target for therapeutic exploitation. A wealth of information about senesc

  5. SIRT1 overexpression antagonizes cellular senescence with activated ERK/S6k1 signaling in human diploid fibroblasts.

    Directory of Open Access Journals (Sweden)

    Jing Huang

    Full Text Available Sir2, a NAD-dependent deacetylase, modulates lifespan in yeasts, worms and flies. The SIRT1, mammalian homologue of Sir2, regulates signaling for favoring survival in stress. But whether SIRT1 has the function to influence cell viability and senescence under non-stressed conditions in human diploid fibroblasts is far from unknown. Our data showed that enforced SIRT1 expression promoted cell proliferation and antagonized cellular senescence with the characteristic features of delayed Senescence-Associated beta-galactosidase (SA-beta-gal staining, reduced Senescence-Associated Heterochromatic Foci (SAHF formation and G1 phase arrest, increased cell growth rate and extended cellular lifespan in human fibroblasts, while dominant-negative SIRT1 allele (H363Y did not significantly affect cell growth and senescence but displayed a bit decreased lifespan. Western blot results showed that SIRT1 reduced the expression of p16(INK4A and promoted phosphorylation of Rb. Our data also exposed that overexpression of SIRT1 was accompanied by enhanced activation of ERK and S6K1 signaling. These effects were mimicked in both WI38 cells and 2BS cells by concentration-dependent resveratrol, a SIRT1 activator. It was noted that treatment of SIRT1-.transfected cells with Rapamycin, a mTOR inhibitor, reduced the phosphorylation of S6K1 and the expression of Id1, implying that SIRT1-induced phosphorylation of S6K1 may be partly for the decreased expression of p16(INK4A and promoted phosphorylation of Rb in 2BS. It was also observed that the expression of SIRT1 and phosphorylation of ERK and S6K1 was declined in senescent 2BS. These findings suggested that SIRT1-promoted cell proliferation and antagonized cellular senescence in human diploid fibroblasts may be, in part, via the activation of ERK/ S6K1 signaling.

  6. Dandelion Extracts Protect Human Skin Fibroblasts from UVB Damage and Cellular Senescence.

    Science.gov (United States)

    Yang, Yafan; Li, Shuangshuang

    2015-01-01

    Ultraviolet (UV) irradiation causes damage in skin by generating excessive reactive oxygen species (ROS) and induction of matrix metalloproteinases (MMPs), leading to skin photoageing. Dandelion extracts have long been used for traditional Chinese medicine and native American medicine to treat cancers, hepatitis, and digestive diseases; however, less is known on the effects of dandelion extracts in skin photoageing. Here we found that dandelion leaf and flower extracts significantly protect UVB irradiation-inhibited cell viability when added before UVB irradiation or promptly after irradiation. Dandelion leaf and flower extracts inhibited UVB irradiation-stimulated MMP activity and ROS generation. Dandelion root extracts showed less action on protecting HDFs from UVB irradiation-induced MMP activity, ROS generation, and cell death. Furthermore, dandelion leaf and flower but not root extracts stimulated glutathione generation and glutathione reductase mRNA expression in the presence or absence of UVB irradiation. We also found that dandelion leaf and flower extracts help absorb UVB irradiation. In addition, dandelion extracts significantly protected HDFs from H2O2-induced cellular senescence. In conclusion, dandelion extracts especially leaf and flower extracts are potent protective agents against UVB damage and H2O2-induced cellular senescence in HDFs by suppressing ROS generation and MMP activities and helping UVB absorption.

  7. Dandelion Extracts Protect Human Skin Fibroblasts from UVB Damage and Cellular Senescence

    Directory of Open Access Journals (Sweden)

    Yafan Yang

    2015-01-01

    Full Text Available Ultraviolet (UV irradiation causes damage in skin by generating excessive reactive oxygen species (ROS and induction of matrix metalloproteinases (MMPs, leading to skin photoageing. Dandelion extracts have long been used for traditional Chinese medicine and native American medicine to treat cancers, hepatitis, and digestive diseases; however, less is known on the effects of dandelion extracts in skin photoageing. Here we found that dandelion leaf and flower extracts significantly protect UVB irradiation-inhibited cell viability when added before UVB irradiation or promptly after irradiation. Dandelion leaf and flower extracts inhibited UVB irradiation-stimulated MMP activity and ROS generation. Dandelion root extracts showed less action on protecting HDFs from UVB irradiation-induced MMP activity, ROS generation, and cell death. Furthermore, dandelion leaf and flower but not root extracts stimulated glutathione generation and glutathione reductase mRNA expression in the presence or absence of UVB irradiation. We also found that dandelion leaf and flower extracts help absorb UVB irradiation. In addition, dandelion extracts significantly protected HDFs from H2O2-induced cellular senescence. In conclusion, dandelion extracts especially leaf and flower extracts are potent protective agents against UVB damage and H2O2-induced cellular senescence in HDFs by suppressing ROS generation and MMP activities and helping UVB absorption.

  8. Dandelion Extracts Protect Human Skin Fibroblasts from UVB Damage and Cellular Senescence

    Science.gov (United States)

    Yang, Yafan; Li, Shuangshuang

    2015-01-01

    Ultraviolet (UV) irradiation causes damage in skin by generating excessive reactive oxygen species (ROS) and induction of matrix metalloproteinases (MMPs), leading to skin photoageing. Dandelion extracts have long been used for traditional Chinese medicine and native American medicine to treat cancers, hepatitis, and digestive diseases; however, less is known on the effects of dandelion extracts in skin photoageing. Here we found that dandelion leaf and flower extracts significantly protect UVB irradiation-inhibited cell viability when added before UVB irradiation or promptly after irradiation. Dandelion leaf and flower extracts inhibited UVB irradiation-stimulated MMP activity and ROS generation. Dandelion root extracts showed less action on protecting HDFs from UVB irradiation-induced MMP activity, ROS generation, and cell death. Furthermore, dandelion leaf and flower but not root extracts stimulated glutathione generation and glutathione reductase mRNA expression in the presence or absence of UVB irradiation. We also found that dandelion leaf and flower extracts help absorb UVB irradiation. In addition, dandelion extracts significantly protected HDFs from H2O2-induced cellular senescence. In conclusion, dandelion extracts especially leaf and flower extracts are potent protective agents against UVB damage and H2O2-induced cellular senescence in HDFs by suppressing ROS generation and MMP activities and helping UVB absorption. PMID:26576225

  9. Cellular senescence and tumor promotion : Is aging the key?

    NARCIS (Netherlands)

    Loaiza, Natalia; Demaria, Marco

    The senescence response is a potent tumor suppressor mechanism characterized by an irreversible growth arrest in response to potentially oncogenic signals to prevent the proliferation of damaged cells. Late in life, some of the features of senescent cells seem to mediate the development of

  10. Cellular and molecular aspects of quinoa leaf senescence.

    Science.gov (United States)

    López-Fernández, María Paula; Burrieza, Hernán Pablo; Rizzo, Axel Joel; Martínez-Tosar, Leandro Julián; Maldonado, Sara

    2015-09-01

    During leaf senescence, degradation of chloroplasts precede to changes in nuclei and other cytoplasmic organelles, RuBisCO stability is progressively lost, grana lose their structure, plastidial DNA becomes distorted and degraded, the number of plastoglobuli increases and abundant senescence-associated vesicles containing electronically dense particles emerge from chloroplasts pouring their content into the central vacuole. This study examines quinoa leaf tissues during development and senescence using a range of well-established markers of programmed cell death (PCD), including: morphological changes in nuclei and chloroplasts, degradation of RuBisCO, changes in chlorophyll content, DNA degradation, variations in ploidy levels, and changes in nuclease profiles. TUNEL reaction and DNA electrophoresis demonstrated that DNA fragmentation in nuclei occurs at early senescence, which correlates with induction of specific nucleases. During senescence, metabolic activity is high and nuclei endoreduplicate, peaking at 4C. At this time, TEM images showed some healthy nuclei with condensed chromatin and nucleoli. We have found that DNA fragmentation, induction of senescence-associated nucleases and endoreduplication take place during leaf senescence. This provides a starting point for further research aiming to identify key genes involved in the senescence of quinoa leaves.

  11. At the intersection of non-coding transcription, DNA repair, chromatin structure, and cellular senescence

    Directory of Open Access Journals (Sweden)

    Ryosuke eOhsawa

    2013-07-01

    Full Text Available It is well accepted that non-coding RNAs play a critical role in regulating gene expression. Recent paradigm-setting studies are now revealing that non-coding RNAs, other than microRNAs, also play intriguing roles in the maintenance of chromatin structure, in the DNA damage response, and in adult human stem cell aging. In this review, we will discuss the complex inter-dependent relationships among non-coding RNA transcription, maintenance of genomic stability, chromatin structure and adult stem cell senescence. DNA damage-induced non-coding RNAs transcribed in the vicinity of the DNA break regulate recruitment of the DNA damage machinery and DNA repair efficiency. We will discuss the correlation between non-coding RNAs and DNA damage repair efficiency and the potential role of changing chromatin structures around double-strand break sites. On the other hand, induction of non-coding RNA transcription from the repetitive Alu elements occurs during human stem cell aging and hinders efficient DNA repair causing entry into senescence. We will discuss how this fine balance between transcription and genomic instability may be regulated by the dramatic changes to chromatin structure that accompany cellular senescence.

  12. Activation of nuclear factor-kappa B signalling promotes cellular senescence

    NARCIS (Netherlands)

    Rovillain, E.; Mansfield, L.; Caetano, C.; Alvarez-Fernandez, M.; Caballero, O. L.; Medema, R. H.; Hummerich, H.; Jat, P. S.

    Cellular senescence is a programme of irreversible cell cycle arrest that normal cells undergo in response to progressive shortening of telomeres, changes in telomeric structure, oncogene activation or oxidative stress. The underlying signalling pathways, of major clinicopathological relevance, are

  13. Activation of nuclear factor-kappa B signalling promotes cellular senescence

    NARCIS (Netherlands)

    Rovillain, E.; Mansfield, L.; Caetano, C.; Alvarez-Fernandez, M.; Caballero, O. L.; Medema, R. H.; Hummerich, H.; Jat, P. S.

    2011-01-01

    Cellular senescence is a programme of irreversible cell cycle arrest that normal cells undergo in response to progressive shortening of telomeres, changes in telomeric structure, oncogene activation or oxidative stress. The underlying signalling pathways, of major clinicopathological relevance, are

  14. Oxidative stress induces senescence in human mesenchymal stem cells

    Energy Technology Data Exchange (ETDEWEB)

    Brandl, Anita [Department of Anesthesiology, University Medical Center Regensburg, Franz-Josef-Strauss-Allee 11, 93042 Regensburg (Germany); Meyer, Matthias; Bechmann, Volker [Department of Trauma Surgery, University Medical Center Regensburg, Franz-Josef-Strauss-Allee 11, 93042 Regensburg (Germany); Nerlich, Michael [Department of Anesthesiology, University Medical Center Regensburg, Franz-Josef-Strauss-Allee 11, 93042 Regensburg (Germany); Angele, Peter, E-mail: Peter.Angele@klinik.uni-regensburg.de [Department of Trauma Surgery, University Medical Center Regensburg, Franz-Josef-Strauss-Allee 11, 93042 Regensburg (Germany)

    2011-07-01

    Mesenchymal stem cells (MSCs) contribute to tissue repair in vivo and form an attractive cell source for tissue engineering. Their regenerative potential is impaired by cellular senescence. The effects of oxidative stress on MSCs are still unknown. Our studies were to investigate into the proliferation potential, cytological features and the telomere linked stress response system of MSCs, subject to acute or prolonged oxidant challenge with hydrogen peroxide. Telomere length was measured using the telomere restriction fragment assay, gene expression was determined by rtPCR. Sub-lethal doses of oxidative stress reduced proliferation rates and induced senescent-morphological features and senescence-associated {beta}-galactosidase positivity. Prolonged low dose treatment with hydrogen peroxide had no effects on cell proliferation or morphology. Sub-lethal and prolonged low doses of oxidative stress considerably accelerated telomere attrition. Following acute oxidant insult p21 was up-regulated prior to returning to initial levels. TRF1 was significantly reduced, TRF2 showed a slight up-regulation. SIRT1 and XRCC5 were up-regulated after oxidant insult and expression levels increased in aging cells. Compared to fibroblasts and chondrocytes, MSCs showed an increased tolerance to oxidative stress regarding proliferation, telomere biology and gene expression with an impaired stress tolerance in aged cells.

  15. Twist1 suppresses senescence programs and thereby accelerates and maintains mutant Kras-induced lung tumorigenesis.

    Directory of Open Access Journals (Sweden)

    Phuoc T Tran

    Full Text Available KRAS mutant lung cancers are generally refractory to chemotherapy as well targeted agents. To date, the identification of drugs to therapeutically inhibit K-RAS have been unsuccessful, suggesting that other approaches are required. We demonstrate in both a novel transgenic mutant Kras lung cancer mouse model and in human lung tumors that the inhibition of Twist1 restores a senescence program inducing the loss of a neoplastic phenotype. The Twist1 gene encodes for a transcription factor that is essential during embryogenesis. Twist1 has been suggested to play an important role during tumor progression. However, there is no in vivo evidence that Twist1 plays a role in autochthonous tumorigenesis. Through two novel transgenic mouse models, we show that Twist1 cooperates with Kras(G12D to markedly accelerate lung tumorigenesis by abrogating cellular senescence programs and promoting the progression from benign adenomas to adenocarcinomas. Moreover, the suppression of Twist1 to physiological levels is sufficient to cause Kras mutant lung tumors to undergo senescence and lose their neoplastic features. Finally, we analyzed more than 500 human tumors to demonstrate that TWIST1 is frequently overexpressed in primary human lung tumors. The suppression of TWIST1 in human lung cancer cells also induced cellular senescence. Hence, TWIST1 is a critical regulator of cellular senescence programs, and the suppression of TWIST1 in human tumors may be an effective example of pro-senescence therapy.

  16. Proteome oxidative carbonylation during oxidative stress-induced premature senescence of WI-38 human fibroblasts

    DEFF Research Database (Denmark)

    Le Boulch, Marine; Ahmed, Emad K; Rogowska-Wrzesinska, Adelina

    2017-01-01

    Accumulation of oxidatively damaged proteins is a hallmark of cellular and organismal ageing, and is also a phenotypic feature shared by both replicative senescence and stress-induced premature senescence of human fibroblasts. Moreover, proteins that are building up as oxidized (i.e. the "Oxi......-proteome") during ageing and age-related diseases represent a restricted set of cellular proteins, indicating that certain proteins are more prone to oxidative carbonylation and subsequent intracellular accumulation. The occurrence of specific carbonylated proteins upon oxidative stress induced premature senescence...... of WI-38 human fibroblasts and their follow-up identification have been addressed in this study. Indeed, it was expected that the identification of these proteins would give insights into the mechanisms by which oxidatively damaged proteins could affect cellular function. Among these proteins, some...

  17. miR-137 Modulates a Tumor Suppressor Network-Inducing Senescence in Pancreatic Cancer Cells

    Directory of Open Access Journals (Sweden)

    Mathieu Neault

    2016-03-01

    Full Text Available Activating K-Ras mutations occurs frequently in pancreatic cancers and is implicated in their development. Cancer-initiating events, such as oncogenic Ras activation, lead to the induction of cellular senescence, a tumor suppressor response. During senescence, the decreased levels of KDM4A lysine demethylase contribute to p53 activation, however, the mechanism by which KDM4A is downregulated is unknown. We show that miR-137 targets KDM4A mRNA during Ras-induced senescence and activates both p53 and retinoblastoma (pRb tumor suppressor pathways. Restoring the KDM4A expression contributed to bypass of miR-137-induced senescence and inhibition of endogenous miR-137 with an miRNA sponge-compromised Ras-induced senescence. miR-137 levels are significantly reduced in human pancreatic tumors, consistent with previous studies revealing a defective senescence response in this cancer type. Restoration of miR-137 expression inhibited proliferation and promoted senescence of pancreatic cancer cells. These results suggest that modulating levels of miR-137 may be important for triggering tumor suppressor networks in pancreatic cancer.

  18. IFI16, an amplifier of DNA-damage response: Role in cellular senescence and aging-associated inflammatory diseases.

    Science.gov (United States)

    Choubey, Divaker; Panchanathan, Ravichandran

    2016-07-01

    DNA-damage induces a DNA-damage response (DDR) in mammalian cells. The response, depending upon the cell-type and the extent of DNA-damage, ultimately results in cell death or cellular senescence. DDR-induced signaling in cells activates the ATM-p53 and ATM-IKKα/β-interferon (IFN)-β signaling pathways, thus leading to an induction of the p53 and IFN-inducible IFI16 gene. Further, upon DNA-damage, DNA accumulates in the cytoplasm, thereby inducing the IFI16 protein and STING-dependent IFN-β production and activation of the IFI16 inflammasome, resulting in the production of proinflammatory cytokines (e.g., IL-1β and IL-18). Increased expression of IFI16 protein in a variety of cell-types promotes cellular senescence. However, reduced expression of IFI16 in cells promotes cell proliferation. Because expression of the IFI16 gene is induced by activation of DNA-damage response in cells and increased levels of IFI16 protein in cells potentiate the p53-mediated transcriptional activation of genes and p53 and pRb-mediated cell cycle arrest, we discuss how an improved understanding of the role of IFI16 protein in cellular senescence and associated inflammatory secretory phenotype is likely to identify the molecular mechanisms that contribute to the development of aging-associated human inflammatory diseases and a failure to cancer therapy.

  19. AMPK induces vascular smooth muscle cell senescence via LKB1 dependent pathway

    Energy Technology Data Exchange (ETDEWEB)

    Sung, Jin Young; Woo, Chang-Hoon [Department of Pharmacology, College of Medicine, Yeungnam University, Daegu 705-717 (Korea, Republic of); Aging-associated Vascular Disease Research Center, College of Medicine, Yeungnam University, Daegu 705-717 (Korea, Republic of); Kang, Young Jin; Lee, Kwang Youn [Department of Pharmacology, College of Medicine, Yeungnam University, Daegu 705-717 (Korea, Republic of); Choi, Hyoung Chul, E-mail: hcchoi@med.yu.ac.kr [Department of Pharmacology, College of Medicine, Yeungnam University, Daegu 705-717 (Korea, Republic of); Aging-associated Vascular Disease Research Center, College of Medicine, Yeungnam University, Daegu 705-717 (Korea, Republic of)

    2011-09-16

    Highlights: {yields} An aging model was established by stimulating VSMC with adriamycin. {yields} Adriamycin increased p-LKB1, p-AMPK, p53 and p21 expressions. {yields} Inhibition of AMPK diminished SA-{beta}-gal staining and restored VSMC proliferation. {yields} p53 and p21 siRNA attenuated adriamycin-induced SA-{beta}-gal staining in VSMC. {yields} p53-p21 pathway is a mediator of LKB1/AMPK induced VSMC senescence. -- Abstract: Vascular cells have a limited lifespan with limited cell proliferation and undergo cellular senescence. The functional changes associated with cellular senescence are thought to contribute to age-related vascular disorders. AMP-activated protein kinase (AMPK) has been discussed in terms of beneficial or harmful effects for aging-related diseases. However, the detailed functional mechanisms of AMPK are largely unclear. An aging model was established by stimulating vascular smooth muscle cell (VSMC) with adriamycin. Adriamycin progressively increased the mRNA and protein expressions of AMPK. The phosphorylation levels of LKB1 and acetyl-CoA carboxylase (ACC), the upstream and downstream of AMPK, were dramatically increased by adriamycin stimulation. The expressions of p53 and p21, which contribute to vascular senescence, were also increased. Inhibition of AMPK diminished senescence-associated {beta}-galactosidase (SA-{beta}-gal) staining, and restored VSMC proliferation. Cytosolic translocation of LKB1 by adriamycin could be a mechanism for AMPK activation in senescence. Furthermore, p53 siRNA and p21 siRNA transfection attenuated adriamycin-induced SA-{beta}-gal staining. These results suggest that LKB1 dependent AMPK activation elicits VSMC senescence and p53-p21 pathway is a mediator of LKB1/AMPK-induced senescence.

  20. High concentrations of NaCl induce cell swelling leading to senescence in human cells.

    Science.gov (United States)

    Yamakami, Yoshimi; Yonekura, Ryuzo; Matsumoto, Yuko; Takauji, Yuki; Miki, Kensuke; Fujii, Michihiko; Ayusawa, Dai

    2016-01-01

    Cell swelling and retardation in DNA replication are always observed in senescent cells. When DNA replication is slowed down with RNA and protein syntheses unchanged in proliferating cells, it causes a phenomenon known as unbalanced growth. The purpose of this study is to assess the role of cell swelling in unbalanced growth in terms of senescence and investigate the mechanism underlying this phenomenon. We tried to induce cell swelling with minimum damage to cells in this study. We perturbed the osmoregulatory functions to induce cell swelling under hypotonic and hypertonic conditions in normal human fibroblasts. Addition of excess NaCl was found to induce significant cell and nuclear swelling in dose- and time-dependent manners. Excess NaCl immediately retarded DNA replication, accumulated cells at G1 phase of the cell cycle, and eventually deprived division potential of the cells. Such cells showed typical senescent cell shape followed by expression of the typical senescence-associated genes. Excess NaCl also activated ERK1/2, p38, and JNK of the mitogen activated protein kinase family. Addition of U0126, an inhibitor of ERK1/2, prevented appearance of senescent features induced by excess NaCl. These results suggest that hypertonic conditions induce cell swelling due to unbalanced growth, thereby leading to cellular senescence.

  1. Bisdemethoxycurcumin Increases Sirt1 to Antagonize t-BHP-Induced Premature Senescence in WI38 Fibroblast Cells

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    Ying-Bo Li

    2013-01-01

    Full Text Available Curcuminoids are well known for their capabilities to combat risk factors that are associated with ageing and cellular senescence. Recent reports have demonstrated that curcuminoids can extend the lifespan of model organisms. However, the underlying mechanisms by which these polyphenic compounds exert these beneficial effects remain unknown. In this study, t-BHP-induced premature senescence model in human fibroblasts was chosen to explore the protective effects of a curcuminoid, bisdemethoxycurcumin (BDMC, on cellular senescence. The results demonstrated that BDMC attenuated oxidative stress-induced senescence-like features which include the induction of an enlarged cellular appearance, higher frequency of senescence-associated β-galactosidase staining activity, appearance of senescence-associated heterochromatic foci in nuclei, decrease in proliferation capability, and alteration in related molecules such as p16 and retinoblastoma protein. Notably, we found that BDMC treatment activated Sirt1/AMPK signaling pathway. Moreover, downregulating Sirt1 by the pharmacological inhibitor nicotianamine or small interfering RNA blocked BDMC-mediated protection against t-BHP-mediated decrease in proliferation. These results suggested that BDMC prevented t-BHP-induced cellular senescence, and BDMC-induced Sirt1 may be a mechanism mediating its beneficial effects.

  2. p16(Ink4a)-induced senescence of pancreatic beta cells enhances insulin secretion.

    Science.gov (United States)

    Helman, Aharon; Klochendler, Agnes; Azazmeh, Narmen; Gabai, Yael; Horwitz, Elad; Anzi, Shira; Swisa, Avital; Condiotti, Reba; Granit, Roy Z; Nevo, Yuval; Fixler, Yaakov; Shreibman, Dorin; Zamir, Amit; Tornovsky-Babeay, Sharona; Dai, Chunhua; Glaser, Benjamin; Powers, Alvin C; Shapiro, A M James; Magnuson, Mark A; Dor, Yuval; Ben-Porath, Ittai

    2016-04-01

    Cellular senescence is thought to contribute to age-associated deterioration of tissue physiology. The senescence effector p16(Ink4a) is expressed in pancreatic beta cells during aging and limits their proliferative potential; however, its effects on beta cell function are poorly characterized. We found that beta cell-specific activation of p16(Ink4a) in transgenic mice enhances glucose-stimulated insulin secretion (GSIS). In mice with diabetes, this leads to improved glucose homeostasis, providing an unexpected functional benefit. Expression of p16(Ink4a) in beta cells induces hallmarks of senescence--including cell enlargement, and greater glucose uptake and mitochondrial activity--which promote increased insulin secretion. GSIS increases during the normal aging of mice and is driven by elevated p16(Ink4a) activity. We found that islets from human adults contain p16(Ink4a)-expressing senescent beta cells and that senescence induced by p16(Ink4a) in a human beta cell line increases insulin secretion in a manner dependent, in part, on the activity of the mechanistic target of rapamycin (mTOR) and the peroxisome proliferator-activated receptor (PPAR)-γ proteins. Our findings reveal a novel role for p16(Ink4a) and cellular senescence in promoting insulin secretion by beta cells and in regulating normal functional tissue maturation with age.

  3. Limited Role of Murine ATM in Oncogene-Induced Senescence and p53-Dependent Tumor Suppression

    Science.gov (United States)

    Martinez-Pastor, Barbara; Ortega-Molina, Ana; Soria, Rebeca; Collado, Manuel; Fernandez-Capetillo, Oscar; Serrano, Manuel

    2009-01-01

    Recent studies in human fibroblasts have provided a new general paradigm of tumor suppression according to which oncogenic signaling produces DNA damage and this, in turn, results in ATM/p53-dependent cellular senescence. Here, we have tested this model in a variety of murine experimental systems. Overexpression of oncogenic Ras in murine fibroblasts efficiently induced senescence but this occurred in the absence of detectable DNA damage signaling, thus suggesting a fundamental difference between human and murine cells. Moreover, lung adenomas initiated by endogenous levels of oncogenic K-Ras presented abundant senescent cells, but undetectable DNA damage signaling. Accordingly, K-Ras-driven adenomas were also senescent in Atm-null mice, and the tumorigenic progression of these lesions was only modestly accelerated by Atm-deficiency. Finally, we have examined chemically-induced fibrosarcomas, which possess a persistently activated DNA damage response and are highly sensitive to the activity of p53. We found that the absence of Atm favored genomic instability in the resulting tumors, but did not affect the persistent DNA damage response and did not impair p53-dependent tumor suppression. All together, we conclude that oncogene-induced senescence in mice may occur in the absence of a detectable DNA damage response. Regarding murine Atm, our data suggest that it plays a minor role in oncogene-induced senescence or in p53-dependent tumor suppression, being its tumor suppressive activity probably limited to the maintenance of genomic stability. PMID:19421407

  4. Limited role of murine ATM in oncogene-induced senescence and p53-dependent tumor suppression.

    Directory of Open Access Journals (Sweden)

    Alejo Efeyan

    Full Text Available Recent studies in human fibroblasts have provided a new general paradigm of tumor suppression according to which oncogenic signaling produces DNA damage and this, in turn, results in ATM/p53-dependent cellular senescence. Here, we have tested this model in a variety of murine experimental systems. Overexpression of oncogenic Ras in murine fibroblasts efficiently induced senescence but this occurred in the absence of detectable DNA damage signaling, thus suggesting a fundamental difference between human and murine cells. Moreover, lung adenomas initiated by endogenous levels of oncogenic K-Ras presented abundant senescent cells, but undetectable DNA damage signaling. Accordingly, K-Ras-driven adenomas were also senescent in Atm-null mice, and the tumorigenic progression of these lesions was only modestly accelerated by Atm-deficiency. Finally, we have examined chemically-induced fibrosarcomas, which possess a persistently activated DNA damage response and are highly sensitive to the activity of p53. We found that the absence of Atm favored genomic instability in the resulting tumors, but did not affect the persistent DNA damage response and did not impair p53-dependent tumor suppression. All together, we conclude that oncogene-induced senescence in mice may occur in the absence of a detectable DNA damage response. Regarding murine Atm, our data suggest that it plays a minor role in oncogene-induced senescence or in p53-dependent tumor suppression, being its tumor suppressive activity probably limited to the maintenance of genomic stability.

  5. The impact of MAO-A in cellular senescence

    OpenAIRE

    Sequeiros, Pedro Emanuel de Magalhães

    2014-01-01

    Dissertação de mestrado em Biologia Celular e Molecular , apresentada à Faculdade de Ciências e Tecnologia da Universidade de Coimbra. Senescência celular é um mecanismo de supressão tumoral e um contribuinte para a perda de função tecidual, a medida que envelhecemos, relacionado assim com o processo a que chamamos envelhecimento. Ele tem sido e caracterizado in vitro, como o resultado de uma resposta a danos no ADN em virtude de telómeros não disfuncionais. Senescência também pod...

  6. The role of cellular senescence during vascular calcification: a key paradigm in aging research.

    Science.gov (United States)

    Mackenzie, N C W; MacRae, V E

    2011-07-01

    Vascular calcification has severe clinical consequences and is considered an accurate predictor of future adverse cardiovascular events. Vascular calcification refers to the deposition of calcium phosphate mineral, most often hydroxyapatite, in arteries. Extensive calcification of the vascular system is a key characteristic of aging. In this article, we outline the mechanisms governing vascular calcification and highlight its association with cellular senescence. This review discusses the molecular mechanisms of cellular senescence and its affect on calcification of vascular cells, the relevance of phosphate regulation and the function of FGF23 and Klotho proteins. The association of vascular calcification and cellular senescence with the rare human aging disorder Hutchison-Gilford Progeria Syndrome (HGPS) is highlighted and the mouse models used to try to determine the underlying pathways are discussed. By understanding the pathways involved in these processes novel drug targets may be elucidated in an effort to reduce the effects of cellular aging as a risk factor in cardiovascular disease.

  7. The role of hypoxia inducible factor-1 alpha in bypassing oncogene-induced senescence.

    Directory of Open Access Journals (Sweden)

    Mehtap Kilic Eren

    Full Text Available Oncogene induced senescence (OIS is a sustained anti-proliferative response acutely induced in primary cells via activation of mitogenic oncogenes such as Ras/BRAF. This mechanism acts as an initial barrier preventing normal cells transformation into malignant cell. Besides oncogenic activation and DNA damage response (DDR, senescence is modulated by a plethora of other factors, and one of the most important one is oxygen tension of the tissue. The aim of this study was to determine the impact of hypoxia on RasV12-induced senescence in human diploid fibroblasts (HDFs. We showed here that hypoxia prevents execution of oncogene induced senescence (OIS, through a strong down-regulation of senescence hallmarks, such as SA- β-galactosidase, H3K9me3, HP1γ, p53, p21CIP1 and p16INK4a in association with induction of hypoxia inducible factor-1α (HIF-1α. In addition, hypoxia also decreased marks of H-RasV12-induced DDR in both cell lines through down-regulation of ATM/ATR, Chk1 and Chk2 phosphorylation as well as decreased γ-H2AX positivity. Utilizing shRNA system targeting HIF-1α we show that HIF-1α is directly involved in down regulation of p53 and its target p21CIP1 but not p16INK4a. In line with this finding we found that knock down of HIF-1α leads to a strong induction of apoptotic response, but not restoration of senescence in Ras expressing HDFs in hypoxia. This indicates that HIF-1α is an important player in early steps of tumorigenesis, leading to suppression of senescence through its negative regulation of p53 and p21CIP1. In our work we describe a mechanism through which hypoxia and specifically HIF-1α preclude cells from maintaining senescence-driven anti proliferative response. These findings indicate the possible mechanism through which hypoxic environment helps premalignant cells to evade impingement of cellular failsafe pathways.

  8. The inhibitory mechanism of Cordyceps sinensis on cigarette smoke extract-induced senescence in human bronchial epithelial cells

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    Liu AL

    2016-07-01

    Full Text Available Ailing Liu,1,2,* Jinxiang Wu,1,* Aijun Li,2 Wenxiang Bi,3 Tian Liu,1 Liuzhao Cao,1 Yahui Liu,1 Liang Dong1 1Department of Pulmonary Diseases, Qilu Hospital, Shandong University, Jinan, Shandong, People’s Republic of China; 2Department of Pulmonary Diseases, Weihai Municipal Hospital, Weihai, Shandong, People’s Republic of China; 3Institute of Biochemistry and Molecular Biology, School of Medicine, Shandong University, Jinan, Shandong, People’s Republic of China *These authors contributed equally to this work Objectives: Cellular senescence is a state of irreversible growth arrest induced either by telomere shortening (replicative senescence or stress. The bronchial epithelial cell is often injured by inhaled toxic substances, such as cigarette smoke. In the present study, we investigated whether exposure to cigarette smoke extract (CSE induces senescence of bronchial epithelial cells; and Cordyceps sinensis mechanism of inhibition of CSE-induced cellular senescence.Methods: Human bronchial epithelial cells (16HBE cells cultured in vitro were treated with CSE and/or C. sinensis. p16, p21, and senescence-associated-galactosidase activity were used to detect cellular senescence with immunofluorescence, quantitative polymerase chain reaction, and Western blotting. Reactive oxygen species (ROS, PI3K/AKT/mTOR and their phosphorylated proteins were examined to testify the activation of signaling pathway by ROS fluorescent staining and Western blotting. Then, inhibitors of ROS and PI3K were used to further confirm the function of this pathway.Results: Cellular senescence was upregulated by CSE treatment, and C. sinensis can decrease CSE-induced cellular senescence. Activation of ROS/PI3K/AKT/mTOR signaling pathway was enhanced by CSE treatment, and decreased when C. sinensis was added. Blocking ROS/PI3K/AKT/mTOR signaling pathway can attenuate CSE-induced cellular senescence.Conclusion: CSE can induce cellular senescence in human bronchial

  9. Hyperosmolarity induced by high glucose promotes senescence in human glomerular mesangial cells.

    Science.gov (United States)

    del Nogal, Maria; Troyano, Nuria; Calleros, Laura; Griera, Mercedes; Rodriguez-Puyol, Manuel; Rodriguez-Puyol, Diego; Ruiz-Torres, María P

    2014-09-01

    Hyperglycemia is involved in the diabetic complication of different organs and can elevate serum osmolarity. Here, we tested whether hyperosmolarity promoted by high glucose levels induces cellular senescence in renal cells. We treated Wistar rats with streptozotocin to induce diabetes or with consecutive daily injections of mannitol to increase serum osmolarity and analyzed p53 and p16 genes in renal cortex by immunohistochemistry. Both diabetic and mannitol treated rats showed a significant increase in serum osmolarity, without significant signs of renal dysfunction, but associated with increased staining for p53 and p16 in the renal cortex. An increase in p53 and p16 expression was also found in renal cortex slices and glomeruli isolated from healthy rats, which were later treated with 30 mM glucose or mannitol. Intracellular mechanisms involved were analyzed in cultured human glomerular mesangial cells treated with 30 mM glucose or mannitol. After treatments, cells showed increased p53, p21 and p16 expression and elevated senescence-associated β-galactosidase activity. Senescence was prevented when myo-inositol was added before treatment. High glucose or mannitol induced constitutive activation of Ras and ERK pathways which, in turn, were activated by oxidative stress. In summary, hyperosmolarity induced renal senescence, particularly in glomerular mesangial cells, increasing oxidative stress, which constitutively activated Ras-ERK 1/2 pathway. Cellular senescence could contribute to the organ dysfunction associated with diabetes.

  10. Irreparable telomeric DNA damage and persistent DDR signalling as a shared causative mechanism of cellular senescence and ageing.

    Science.gov (United States)

    Rossiello, Francesca; Herbig, Utz; Longhese, Maria Pia; Fumagalli, Marzia; d'Adda di Fagagna, Fabrizio

    2014-06-01

    The DNA damage response (DDR) orchestrates DNA repair and halts cell cycle. If damage is not resolved, cells can enter into an irreversible state of proliferative arrest called cellular senescence. Organismal ageing in mammals is associated with accumulation of markers of cellular senescence and DDR persistence at telomeres. Since the vast majority of the cells in mammals are non-proliferating, how do they age? Are telomeres involved? Also oncogene activation causes cellular senescence due to altered DNA replication and DDR activation in particular at the telomeres. Is there a common mechanism shared among apparently distinct types of cellular senescence? And what is the role of telomeric DNA damage?

  11. Changes in the Transcriptome of Human Astrocytes Accompanying Oxidative Stress-Induced Senescence

    Science.gov (United States)

    Crowe, Elizabeth P.; Tuzer, Ferit; Gregory, Brian D.; Donahue, Greg; Gosai, Sager J.; Cohen, Justin; Leung, Yuk Y.; Yetkin, Emre; Nativio, Raffaella; Wang, Li-San; Sell, Christian; Bonini, Nancy M.; Berger, Shelley L.; Johnson, F. Brad; Torres, Claudio

    2016-01-01

    Aging is a major risk factor for many neurodegenerative disorders. A key feature of aging biology that may underlie these diseases is cellular senescence. Senescent cells accumulate in tissues with age, undergo widespread changes in gene expression, and typically demonstrate altered, pro-inflammatory profiles. Astrocyte senescence has been implicated in neurodegenerative disease, and to better understand senescence-associated changes in astrocytes, we investigated changes in their transcriptome using RNA sequencing. Senescence was induced in human fetal astrocytes by transient oxidative stress. Brain-expressed genes, including those involved in neuronal development and differentiation, were downregulated in senescent astrocytes. Remarkably, several genes indicative of astrocytic responses to injury were also downregulated, including glial fibrillary acidic protein and genes involved in the processing and presentation of antigens by major histocompatibility complex class II proteins, while pro-inflammatory genes were upregulated. Overall, our findings suggest that senescence-related changes in the function of astrocytes may impact the pathogenesis of age-related brain disorders. PMID:27630559

  12. Changes in the Transcriptome of Human Astrocytes Accompanying Oxidative Stress-induced Senescence

    Directory of Open Access Journals (Sweden)

    Elizabeth P. Crowe

    2016-08-01

    Full Text Available Aging is a major risk factor for many neurodegenerative disorders. A key feature of aging biology that may underlie these diseases is cellular senescence. Senescent cells accumulate in tissues with age, undergo widespread changes in gene expression, and typically demonstrate altered, pro-inflammatory profiles. Astrocyte senescence has been implicated in neurodegenerative disease, and to better understand senescence-associated changes in astrocytes, we investigated changes in their transcriptome using RNA sequencing. Senescence was induced in human fetal astrocytes by transient oxidative stress. Brain-expressed genes, including those involved in neuronal development and differentiation, were downregulated in senescent astrocytes. Remarkably, several genes indicative of astrocytic responses to injury were also downregulated, including GFAP and genes involved in the processing and presentation of antigens by major histocompatibility complex class II proteins, while pro-inflammatory genes were upregulated. Overall, our findings suggest that senescence-related changes in the function of astrocytes may impact the pathogenesis of age-related brain disorders.

  13. Mitochondrial DNA Hypomethylation Is a Biomarker Associated with Induced Senescence in Human Fetal Heart Mesenchymal Stem Cells

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    Dehai Yu

    2017-01-01

    Full Text Available Background. Fetal heart can regenerate to restore its normal anatomy and function in response to injury, but this regenerative capacity is lost within the first week of postnatal life. Although the specific molecular mechanisms remain to be defined, it is presumed that aging of cardiac stem or progenitor cells may contribute to the loss of regenerative potential. Methods. To study this aging-related dysfunction, we cultured mesenchymal stem cells (MSCs from human fetal heart tissues. Senescence was induced by exposing cells to chronic oxidative stress/low serum. Mitochondrial DNA methylation was examined during the period of senescence. Results. Senescent MSCs exhibited flattened and enlarged morphology and were positive for the senescence-associated beta-galactosidase (SA-β-Gal. By scanning the entire mitochondrial genome, we found that four CpG islands were hypomethylated in close association with senescence in MSCs. The mitochondrial COX1 gene, which encodes the main subunit of the cytochrome c oxidase complex and contains the differentially methylated CpG island 4, was upregulated in MSCs in parallel with the onset of senescence. Knockdown of DNA methyltransferases (DNMT1, DNMT3a, and DNMT3B also upregulated COX1 expression and induced cellular senescence in MSCs. Conclusions. This study demonstrates that mitochondrial CpG hypomethylation may serve as a critical biomarker associated with cellular senescence induced by chronic oxidative stress.

  14. Irreversibility of cellular senescence: dual roles of p16INK4a/Rb-pathway in cell cycle control

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    Hara Eiji

    2007-03-01

    Full Text Available Abstract The retinoblastoma (Rb tumor suppressor gene product, pRb, has an established role in the implementation of cellular senescence, the state of irreversible G1 cell cycle arrest provoked by diverse oncogenic stresses. In murine cells, senescence cell cycle arrest can be reversed by subsequent inactivation of pRb, indicating that pRb is required not only for the onset of cellular senescence, but also for the maintenance of senescence program in murine cells. However, in human cells, once pRb is fully activated by p16INK4a, senescence cell cycle arrest becomes irreversible and is no longer revoked by subsequent inactivation of pRb, suggesting that p16INK4a/Rb-pathway activates an alternative mechanism to irreversibly block the cell cycle in human senescent cells. Here, we discuss the molecular mechanism underlying the irreversibility of senescence cell cycle arrest and its potential towards tumor suppression.

  15. The Impacts of Cellular Senescence in Elderly Pneumonia and in Age-Related Lung Diseases That Increase the Risk of Respiratory Infections.

    Science.gov (United States)

    Yanagi, Shigehisa; Tsubouchi, Hironobu; Miura, Ayako; Matsuo, Ayako; Matsumoto, Nobuhiro; Nakazato, Masamitsu

    2017-02-25

    Pneumonia generates considerable negative impacts on the elderly. Despite the widespread uses of vaccines and appropriate antibiotics, the morbidity and mortality of elderly pneumonia are significantly higher compared to the counterparts of young populations. The definitive mechanisms of high vulnerability in the elderly against pathogen threats are unclear. Age-associated, chronic low-grade inflammation augments the susceptibility and severity of pneumonia in the elderly. Cellular senescence, one of the hallmarks of aging, has its own characteristics, cell growth arrest and senescence-associated secretory phenotype (SASP). These properties are beneficial if the sequence of senescence-clearance-regeneration is transient in manner. However, persisting senescent cell accumulation and excessive SASP might induce sustained low-grade inflammation and disruption of normal tissue microenvironments in aged tissue. Emerging evidence indicates that cellular senescence is a key component in the pathogenesis of chronic obstructive pulmonary disease (COPD) and idiopathic pulmonary fibrosis (IPF), which are known to be age-related and increase the risk of pneumonia. In addition to their structural collapses, COPD and IPF might increase the vulnerability to pathogen insults through SASP. Here, we discuss the current advances in understanding of the impacts of cellular senescence in elderly pneumonia and in these chronic lung disorders that heighten the risk of respiratory infections.

  16. Bacterial Intoxication Evokes Cellular Senescence with Persistent DNA Damage and Cytokine Signaling

    DEFF Research Database (Denmark)

    Blazkova, Hana; Krejcikova, Katerina; Moudry, Pavel;

    2009-01-01

    to such intoxication are mechanistically incompletely understood. Here we show that both normal and cancer cells (BJ, IMR-90 and WI-38 fibroblasts, HeLa and U2-OS cell lines) that survive the acute phase of intoxication by Haemophilus ducreyi CDT possess the hallmarks of cellular senescence. This characteristic...

  17. Are microRNAs true sensors of ageing and cellular senescence?

    Science.gov (United States)

    Williams, Justin; Smith, Flint; Kumar, Subodh; Vijayan, Murali; Reddy, P Hemachandra

    2017-05-01

    All living beings are programmed to death due to aging and age-related processes. Aging is a normal process of every living species. While all cells are inevitably progressing towards death, many disease processes accelerate the aging process, leading to senescence. Pathologies such as Alzheimer's disease, Parkinson's disease, multiple sclerosis, amyotrophic lateral sclerosis, Huntington's disease, cardiovascular disease, cancer, and skin diseases have been associated with deregulated aging. Healthy aging can delay onset of all age-related diseases. Genetics and epigenetics are reported to play large roles in accelerating and/or delaying the onset of age-related diseases. Cellular mechanisms of aging and age-related diseases are not completely understood. However, recent molecular biology discoveries have revealed that microRNAs (miRNAs) are potential sensors of aging and cellular senescence. Due to miRNAs capability to bind to the 3' untranslated region (UTR) of mRNA of specific genes, miRNAs can prevent the translation of specific genes. The purpose of our article is to highlight recent advancements in miRNAs and their involvement in cellular changes in aging and senescence. Our article discusses the current understanding of cellular senescence, its interplay with miRNAs regulation, and how they both contribute to disease processes. Copyright © 2016 Elsevier B.V. All rights reserved.

  18. Cellular senescence in aging and age-related disease: from mechanisms to therapy

    NARCIS (Netherlands)

    Childs, B.G.; Durik, M.; Baker, D.J.; Deursen, J.M.A. van

    2015-01-01

    Cellular senescence, a process that imposes permanent proliferative arrest on cells in response to various stressors, has emerged as a potentially important contributor to aging and age-related disease, and it is an attractive target for therapeutic exploitation. A wealth of information about

  19. Low zinc environment induces stress signaling, senescence and mixed cell death modalities in colon cancer cells.

    Science.gov (United States)

    Rudolf, Emil; Rudolf, Kamil

    2015-12-01

    Currently it is not clear what type of the final cellular response (i.e. cell death modality or senescence) is induced upon chronic intracellular zinc depletion in colon cancer cells. To address this question, isogenic colon cancer lines SW480 and SW620 exposed to low zinc environment were studied over the period of 6 weeks. Low zinc environment reduced total as well as free intracellular zinc content in both cell lines. Decreased intracellular zinc content resulted in changes in cellular proliferation, cell cycle distribution and activation of stress signaling. In addition, colonocytes with low zinc content displayed increased levels of oxidative stress, changes in mitochondrial activity but in the absence of significant DNA damage. Towards the end of treatment (4th-6th week), exposed cells started to change morphologically, and typical markers of senescence as well as cell death appeared. Of two examined colon cancer cell lines, SW480 cells proved to activate predominantly senescent phenotype, with frequent form of demise being necrosis and mixed cell death modality but not apoptosis. Conversely, SW620 cells activated mostly cell death, with relatively equal distribution of apoptosis and mixed types, while senescent phenotypes and necrosis were present only in a small fraction of cell populations. Addition of zinc at the beginning of 4th week of treatment significantly suppressed cell death phenotypes in both cell lines but had no significant effect on senescence. In conclusion, presented results demonstrate variability of responses to chronic zinc depletion in colon cancer as modeled in vitro.

  20. Happily (never after: Aging in the context of oxidative stress, proteostasis loss and cellular senescence

    Directory of Open Access Journals (Sweden)

    Annika Höhn

    2017-04-01

    Full Text Available Aging is a complex phenomenon and its impact is becoming more relevant due to the rising life expectancy and because aging itself is the basis for the development of age-related diseases such as cancer, neurodegenerative diseases and type 2 diabetes. Recent years of scientific research have brought up different theories that attempt to explain the aging process. So far, there is no single theory that fully explains all facets of aging. The damage accumulation theory is one of the most accepted theories due to the large body of evidence found over the years. Damage accumulation is thought to be driven, among others, by oxidative stress. This condition results in an excess attack of oxidants on biomolecules, which lead to damage accumulation over time and contribute to the functional involution of cells, tissues and organisms. If oxidative stress persists, cellular senescence is a likely outcome and an important hallmark of aging. Therefore, it becomes crucial to understand how senescent cells function and how they contribute to the aging process. This review will cover cellular senescence features related to the protein pool such as morphological and molecular hallmarks, how oxidative stress promotes protein modifications, how senescent cells cope with them by proteostasis mechanisms, including antioxidant enzymes and proteolytic systems. We will also highlight the nutritional status of senescent cells and aged organisms (including human clinical studies by exploring trace elements and micronutrients and on their importance to develop strategies that might increase both, life and health span and postpone aging onset.

  1. Intermittent heterochronic plasma exchange as a modality for delaying cellular senescence-a hypothesis.

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    Kiprov, Dobri D

    2013-12-01

    The population of baby boomers (age 60-65) is rapidly increasing globally. The aging of the human body is associated with the decline of cellular function which leads to the development of a variety of diseases. The increased demand for health care for the aging population creates significant financial burden to any healthcare system. Developing strategies and health intervention methods to ameliorate this situation is paramount. Experiments utilizing heterochronic parabiosis in mice have demonstrated that replacing the aging cellular milieu with the plasma of a young experimental animal leads to reversal of cellular senescence. This article describes a hypothetical model of intermittent heterochronic plasma exchange in humans as a modality for heterochronic parabiosis in an attempt to delay cellular senescence. Copyright © 2013 Wiley Periodicals, Inc.

  2. Effect of autophagy induced by dexamethasone on senescence in chondrocytes

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    Xue, Enxing; Zhang, Yu; Song, Bing; Xiao, Jun; Shi, Zhanjun

    2016-01-01

    The aim of the current study was to explore the effects of dexamethasone (DXM) on autophagy and senescence in chondrocytes. Collagen II and aggrecan were examined in normal chondrocytes isolated from Sprague-Dawley rats. Following stimulation with DXM, LysoTracker Red staining, monodansylcadaverine (MDC) staining, green fluorescent protein-red fluorescent protein-light chain 3 (LC3) and western blotting were used to detect autophagy levels in the chondrocytes. Mechanistic target of rapamycin (mTOR) pathway-associated molecules were investigated by western blotting. Cell senescence was analyzed by senescence-associated (SA)-β-galactosidase (β-gal) staining. A dose-dependent increase in the number of autophagic vacuoles was observed in the DXM-treated chondrocytes, as demonstrated by LysoTracker Red and MDC staining. A dose-dependent increase in autophagosome formation was observed in the DXM-treated chondrocytes. Expression of LC3-II and beclin-1 was increased by DXM, in particular in the cells treated with DXM for 4 days. However, P62 expression was reduced as a result of treatment. SA-β-gal staining indicated that DXM increased cell senescence. Notably, DXM-induced cell senescence was exacerbated by the autophagic inhibitor 3-MA. Autophagy induced by DXM protected chondrocytes from senescence, and it is suggested that the mTOR pathway may be involved in the activation of DXM-induced autophagy. PMID:27572674

  3. Human papillomavirus oncoprotein E7 targets the promyelocytic leukemia protein and circumvents cellular senescence via the Rb and p53 tumor suppressor pathways.

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    Bischof, Oliver; Nacerddine, Karim; Dejean, Anne

    2005-02-01

    Cellular senescence can be triggered by a variety of signals, including loss of telomeric integrity or intense oncogenic signaling, and is considered a potent, natural tumor suppressor mechanism. Previously, it was shown that the promyelocytic leukemia protein (PML) induces cellular senescence when overexpressed in primary human fibroblasts. The mechanism by which the PML IV isoform elicits this irreversible growth arrest is believed to involve activation of the tumor suppressor pathways p21/p53 and p16/Rb; however, a requirement for either pathway has not been demonstrated unequivocally. To investigate the individual contributions of p53 and Rb to PML-induced senescence, we used oncoproteins E6 and E7 from human papillomaviruses (HPVs), which predominantly target p53 and Rb. We show that E7, but not E6, circumvents PML-induced senescence. Using different E7 mutant proteins, dominant negative cyclin-dependent kinase 4, and p16 RNA interference, we demonstrate that Rb-related and Rb-independent mechanisms of E7 are necessary for subversion of PML-induced senescence and we identify PML as a novel target for E7. Interaction between E7 and a functional prosenescence complex composed of PML, p53, and CBP perturbs transcriptional activation of p53, thus highlighting a significant effect also on the p53 tumor suppressor pathway. Given the importance of HPV in the pathogenesis of cervical cancer, our results warrant a more detailed analyses of PML in HPV infections.

  4. Rejuvenation of MPTP-induced human neural precursor cell senescence by activating autophagy

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    Zhu, Liang [East Hospital, Tongji University School of Medicine, Shanghai (China); Dong, Chuanming [East Hospital, Tongji University School of Medicine, Shanghai (China); Department of Anatomy and Neurobiology, The Jiangsu Key Laboratory of Neuroregeneration, Nantong University, Nantong (China); Sun, Chenxi; Ma, Rongjie; Yang, Danjing [East Hospital, Tongji University School of Medicine, Shanghai (China); Zhu, Hongwen, E-mail: hongwen_zhu@hotmail.com [Tianjin Hospital, Tianjin Academy of Integrative Medicine, Tianjin (China); Xu, Jun, E-mail: xunymc2000@yahoo.com [East Hospital, Tongji University School of Medicine, Shanghai (China)

    2015-08-21

    Aging of neural stem cell, which can affect brain homeostasis, may be caused by many cellular mechanisms. Autophagy dysfunction was found in aged and neurodegenerative brains. However, little is known about the relationship between autophagy and human neural stem cell (hNSC) aging. The present study used 1-methyl-4-phenyl-1, 2, 3, 6-tetrahydropyridine (MPTP) to treat neural precursor cells (NPCs) derived from human embryonic stem cell (hESC) line H9 and investigate related molecular mechanisms involved in this process. MPTP-treated NPCs were found to undergo premature senescence [determined by increased senescence-associated-β-galactosidase (SA-β-gal) activity, elevated intracellular reactive oxygen species level, and decreased proliferation] and were associated with impaired autophagy. Additionally, the cellular senescence phenotypes were manifested at the molecular level by a significant increase in p21 and p53 expression, a decrease in SOD2 expression, and a decrease in expression of some key autophagy-related genes such as Atg5, Atg7, Atg12, and Beclin 1. Furthermore, we found that the senescence-like phenotype of MPTP-treated hNPCs was rejuvenated through treatment with a well-known autophagy enhancer rapamycin, which was blocked by suppression of essential autophagy gene Beclin 1. Taken together, these findings reveal the critical role of autophagy in the process of hNSC aging, and this process can be reversed by activating autophagy. - Highlights: • We successfully establish hESC-derived neural precursor cells. • MPTP treatment induced senescence-like state in hESC-derived NPCs. • MPTP treatment induced impaired autophagy of hESC-derived NPCs. • MPTP-induced hESC-derived NPC senescence was rejuvenated by activating autophagy.

  5. Roles of TP53 in determining therapeutic sensitivity, growth, cellular senescence, invasion and metastasis.

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    McCubrey, James A; Lertpiriyapong, Kvin; Fitzgerald, Timothy L; Martelli, Alberto M; Cocco, Lucio; Rakus, Dariusz; Gizak, Agnieszka; Libra, Massimo; Cervello, Melchiorre; Montalto, Guiseppe; Yang, Li V; Abrams, Stephen L; Steelman, Linda S

    2017-01-01

    TP53 is a critical tumor suppressor gene that regulates cell cycle progression, apoptosis, cellular senescence and many other properties critical for control of normal cellular growth and death. Due to the pleiotropic effects that TP53 has on gene expression and cellular physiology, mutations at this tumor suppressor gene result in diverse physiological effects. T53 mutations are frequently detected in numerous cancers. The expression of TP53 can be induced by various agents used to treat cancer patients such as chemotherapeutic drugs and ionizing radiation. Radiation will induce Ataxia telangiectasia mutated (ATM) and other kinases that results in the phosphorylation and activation of TP53. TP53 is also negatively regulated by other mechanisms, such as ubiquitination by ligases such as MDM2. While TP53 has been documented to control the expression of many "classical" genes (e.g., p21(Cip-1), PUMA, Bax) by transcriptional mechanisms for quite some time, more recently TP53 has been shown to regulate microRNA (miR) gene expression. Different miRs can promote oncogenesis (oncomiR) whereas others act to inhibit tumor progression (tumor suppressor miRs). Targeted therapies to stabilize TP53 have been developed by various approaches, MDM2/MDM4 inhibitors have been developed to stabilize TP53 in TP53-wild type (WT) tumors. In addition, small molecules have been isolated that will reactivate certain mutant TP53s. Both of these types of inhibitors are in clinical trials. Understanding the actions of TP53 may yield novel approaches to suppress cancer, aging and other health problems.

  6. Adiponectin Suppresses UVB-Induced Premature Senescence and hBD2 Overexpression in Human Keratinocytes.

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    Kim, MinJeong; Park, Kui Young; Lee, Mi-Kyung; Jin, Taewon; Seo, Seong Jun

    2016-01-01

    Recent studies have revealed that adiponectin can suppress cellular inflammatory signaling pathways. This study aimed to elucidate the effect of adiponectin on the unregulated production of hBD2 in UVB-induced premature senescent keratinocytes. We constructed an in vitro model of premature senescent keratinocytes through repeated exposure to low energy UVB. After repeated low energy UVB exposure, there was significant generation of reactive oxygen species (ROS) and induction of senescence-associated markers, including senescence associated beta-galactosidase activity and expression of p16INK4a and histone H2AX. In addition, the present clinical study showed higher expression of hBD2 in sun-exposed skin of elderly group, and the overexpression of hBD2 was observed by c-Fos activation in vitro. Adiponectin has the ability to scavenge ROS and consequently inhibit MAPKs and SA-markers in UVB-exposed keratinocytes. An inhibitor study demonstrated that adiponectin downregulated hBD2 mRNA expression through suppression of the AP-1 transcription factor components c-Fos via inactivation of p38 MAPK. Collectively, the dysregulated production of hBD2 by the induction of oxidative stress was attenuated by adiponectin through the suppression of p38 and JNK/SAPK MAPK signaling in UVB-mediated premature senescent inducible conditions. These results suggest the feasibility of adiponectin as an anti-photoaging and anti-inflammatory agent in the skin.

  7. DNA Hypomethylation and Histone Variant macroH2A1 Synergistically Attenuate Chemotherapy-Induced Senescence to Promote Hepatocellular Carcinoma Progression

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    Borghesan, Michela; Fusilli, Caterina; Rappa, Francesca; Panebianco, Concetta; Rizzo, Giovanni; Oben, Jude A.; Mazzoccoli, Gianluigi; Faulkes, Chris; Pata, Illar; Agodi, Antonella; Rezaee, Farhad; Minogue, Shane; Warren, Alessandra; Peterson, Abigail; Sedivy, John M.; Douet, Julien; Buschbeck, Marcus; Cappello, Francesco; Mazza, Tommaso; Pazienza, Valerio; Vinciguerra, Manlio

    2016-01-01

    Aging is a major risk factor for progression of liver diseases to hepatocellular carcinoma (HCC). Cellular senescence contributes to age-related tissue dysfunction, but the epigenetic basis underlying drug-induced senescence remains unclear. macroH2A1, a variant of histone H2A, is a marker of

  8. Glucagon-Like Peptide 1 Prevents Reactive Oxygen Species-Induced Endothelial Cell Senescence Through the Activation of Protein Kinase A

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    Oeseburg, Hisko; de Boer, Rudolf A.; Buikema, Hendrik; van der Harst, Pim; van Gilst, Wiek H.; Sillje, Herman H. W.

    2010-01-01

    Objective-Endothelial cell senescence is an important contributor to vascular aging and is increased under diabetic conditions. Here we investigated whether the antidiabetic hormone glucagon-like peptide 1 (GLP-1) could prevent oxidative stress-induced cellular senescence in endothelial cells. Metho

  9. hnRNP A1 antagonizes cellular senescence and senescence-associated secretory phenotype via regulation of SIRT1 mRNA stability.

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    Wang, Hui; Han, Limin; Zhao, Ganye; Shen, Hong; Wang, Pengfeng; Sun, Zhaomeng; Xu, Chenzhong; Su, Yuanyuan; Li, Guodong; Tong, Tanjun; Chen, Jun

    2016-09-09

    Senescent cells display a senescence-associated secretory phenotype (SASP) which contributes to tumor suppression, aging, and cancer. However, the underlying mechanisms for SASP regulation are not fully elucidated. SIRT1, a nicotinamide adenosine dinucleotide-dependent deacetylase, plays multiple roles in metabolism, inflammatory response, and longevity, etc. However, its posttranscriptional regulation and its roles in cellular senescence and SASP regulation are still elusive. Here, we identify the RNA-binding protein hnRNP A1 as a posttranscriptional regulator of SIRT1, as well as cell senescence and SASP regulator. hnRNP A1 directly interacts with the 3' untranslated region of SIRT1 mRNA, promotes its stability, and increases SIRT1 expression. hnRNP A1 delays replicative cellular senescence and prevents from Ras OIS via upregulation of SIRT1 expression to deacetylate NF-κB, thus blunting its transcriptional activity and subsequent IL-6/IL-8 induction. hnRNP A1 overexpression promotes cell transformation and tumorigenesis in a SIRT1-dependent manner. Together, our findings unveil a novel posttranscriptional regulation of SIRT1 by hnRNP A1 and uncover a critical role of hnRNP A1-SIRT1-NF-κB pathway in regulating cellular senescence and SASP expression. © 2016 The Authors. Aging Cell published by the Anatomical Society and John Wiley & Sons Ltd.

  10. The Impacts of Cellular Senescence in Elderly Pneumonia and in Age-Related Lung Diseases That Increase the Risk of Respiratory Infections

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    Shigehisa Yanagi

    2017-02-01

    Full Text Available Pneumonia generates considerable negative impacts on the elderly. Despite the widespread uses of vaccines and appropriate antibiotics, the morbidity and mortality of elderly pneumonia are significantly higher compared to the counterparts of young populations. The definitive mechanisms of high vulnerability in the elderly against pathogen threats are unclear. Age-associated, chronic low-grade inflammation augments the susceptibility and severity of pneumonia in the elderly. Cellular senescence, one of the hallmarks of aging, has its own characteristics, cell growth arrest and senescence-associated secretory phenotype (SASP. These properties are beneficial if the sequence of senescence–clearance–regeneration is transient in manner. However, persisting senescent cell accumulation and excessive SASP might induce sustained low-grade inflammation and disruption of normal tissue microenvironments in aged tissue. Emerging evidence indicates that cellular senescence is a key component in the pathogenesis of chronic obstructive pulmonary disease (COPD and idiopathic pulmonary fibrosis (IPF, which are known to be age-related and increase the risk of pneumonia. In addition to their structural collapses, COPD and IPF might increase the vulnerability to pathogen insults through SASP. Here, we discuss the current advances in understanding of the impacts of cellular senescence in elderly pneumonia and in these chronic lung disorders that heighten the risk of respiratory infections.

  11. Cellular senescence in livers from children with end stage liver disease.

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    Gabriela Gutierrez-Reyes

    Full Text Available BACKGROUND: Senescent cells occur in adults with cirrhotic livers independent of the etiology. AIM: Investigate the presence rate of cellular senescence and expression of cell cycle check points in livers from children with end stage disease. METHODOLOGY/PRINCIPAL FINDINGS: Livers of five children aged three years or less undergoing liver transplantation due to tyrosinemia (n = 1, biliary atresia (n = 2, or fulminant hepatitis (n = 2 were analyzed for senescence associated beta-galactosidase (SA-betagal activity and p16INK4a, p21cip1 and p53. All livers displayed positive cellular staining for SA-betagal in the canals of Hering and interlobular biliary ducts. In the presence of cirrhosis (3/5 cases SA-betagal was found at the cholangioles and hepatocytes surrounding the regenerative nodules. Children with fulminant hepatic failure without cirrhosis had significant ductular transformation with intense SA-betagal activity. No SA-betagal activity was evident in the fibrous septa. Staining for p53 had a similar distribution to that observed for SA-betagal. Staining for p16(INK4a and p21(cip1 was positive in the explanted liver of the patient with tyrosinemia, in the hepatocytes, the canals of Hering, cholangioles and interlobular bile ducts. In the livers with fulminant hepatitis, p21(cip1 staining occurred in the areas of ductular transformation and in the interlobular bile ducts. CONCLUSIONS/SIGNIFICANCE: Cellular senescence in livers of children with end stage disease is associated with damage rather than corresponding to an age dependent phenomenon. Further studies are needed to support the hypothesis that these senescence markers correlate with disease progression.

  12. 2, 3, 7, 8-Tetrachlorodibenzo-P-dioxin (TCDD induces premature senescence in human and rodent neuronal cells via ROS-dependent mechanisms.

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    Chunhua Wan

    Full Text Available The widespread environmental pollutant 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD is a potent toxicant that causes significant neurotoxicity. However, the biological events that participate in this process remain largely elusive. In the present study, we demonstrated that TCDD exposure triggered apparent premature senescence in rat pheochromocytoma (PC12 and human neuroblastoma SH-SY5Y cells. Senescence-associated β-galactosidase (SA-β-Gal assay revealed that TCDD induced senescence in PC12 neuronal cells at doses as low as 10 nM. TCDD led to F-actin reorganization and the appearance of an alternative senescence marker, γ-H2AX foci, both of which are important features of cellular senescence. In addition, TCDD exposure altered the expression of senescence marker proteins, such as p16, p21 and p-Rb, in both dose- and time-dependent manners. Furthermore, we demonstrated that TCDD promotes mitochondrial dysfunction and the accumulation of cellular reactive oxygen species (ROS in PC12 cells, leading to the activation of signaling pathways that are involved in ROS metabolism and senescence. TCDD-induced ROS generation promoted significant oxidative DNA damage and lipid peroxidation. Notably, treatment with the ROS scavenger N-acetylcysteine (NAC markedly attenuated TCDD-induced ROS production, cellular oxidative damage and neuronal senescence. Moreover, we found that TCDD induced a similar ROS-mediated senescence response in human neuroblastoma SH-SY5Y cells. In sum, these results demonstrate for the first time that TCDD induces premature senescence in neuronal cells by promoting intracellular ROS production, supporting the idea that accelerating the onset of neuronal senescence may be an important mechanism underlying TCDD-induced neurotoxic effects.

  13. 2, 3, 7, 8-Tetrachlorodibenzo-P-dioxin (TCDD) induces premature senescence in human and rodent neuronal cells via ROS-dependent mechanisms.

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    Wan, Chunhua; Liu, Jiao; Nie, Xiaoke; Zhao, Jianya; Zhou, Songlin; Duan, Zhiqing; Tang, Cuiying; Liang, Lingwei; Xu, Guangfei

    2014-01-01

    The widespread environmental pollutant 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) is a potent toxicant that causes significant neurotoxicity. However, the biological events that participate in this process remain largely elusive. In the present study, we demonstrated that TCDD exposure triggered apparent premature senescence in rat pheochromocytoma (PC12) and human neuroblastoma SH-SY5Y cells. Senescence-associated β-galactosidase (SA-β-Gal) assay revealed that TCDD induced senescence in PC12 neuronal cells at doses as low as 10 nM. TCDD led to F-actin reorganization and the appearance of an alternative senescence marker, γ-H2AX foci, both of which are important features of cellular senescence. In addition, TCDD exposure altered the expression of senescence marker proteins, such as p16, p21 and p-Rb, in both dose- and time-dependent manners. Furthermore, we demonstrated that TCDD promotes mitochondrial dysfunction and the accumulation of cellular reactive oxygen species (ROS) in PC12 cells, leading to the activation of signaling pathways that are involved in ROS metabolism and senescence. TCDD-induced ROS generation promoted significant oxidative DNA damage and lipid peroxidation. Notably, treatment with the ROS scavenger N-acetylcysteine (NAC) markedly attenuated TCDD-induced ROS production, cellular oxidative damage and neuronal senescence. Moreover, we found that TCDD induced a similar ROS-mediated senescence response in human neuroblastoma SH-SY5Y cells. In sum, these results demonstrate for the first time that TCDD induces premature senescence in neuronal cells by promoting intracellular ROS production, supporting the idea that accelerating the onset of neuronal senescence may be an important mechanism underlying TCDD-induced neurotoxic effects.

  14. The DNA damage response induces inflammation and senescence by inhibiting autophagy of GATA4

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    Kang, Chanhee; Xu, Qikai; Martin, Timothy D; Li, Mamie Z; Demaria, Marco; Aron, Liviu; Lu, Tao; Yankner, Bruce A; Campisi, Judith; Elledge, Stephen J

    2015-01-01

    Cellular senescence is a terminal stress-activated program controlled by the p53 and p16(INK4a) tumor suppressor proteins. A striking feature of senescence is the senescence-associated secretory phenotype (SASP), a pro-inflammatory response linked to tumor promotion and aging. We have identified the

  15. TGFβ-dependent gene expression shows that senescence correlates with abortive differentiation along several lineages in Myc-induced lymphomas.

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    Müller, Judith; Samans, Birgit; van Riggelen, Jan; Fagà, Giovanni; Peh K N, Raquel; Wei, Chia-Lin; Müller, Heiko; Amati, Bruno; Felsher, Dean; Eilers, Martin

    2010-12-01

    Deregulated expression of Myc under the control of an immunoglobulin enhancer induces lymphoma formation in mice. The development of lymphomas is limited by TGFβ-dependent senescence and high levels of Myc expression are continuously required to antagonize senescence. The biological processes underlying senescence are not fully resolved. We report here a comprehensive analysis of TGFβ-dependent alterations in gene expression when the Myc transgene is switched off. Our data show that Myc-induced target genes are downregulated in a TGFβ-independent manner. In contrast, TGFβ is required to upregulate a broad spectrum of genes that are characteristic of different T-cell lineages when Myc is turned off. The analysis reveals a significant overlap between these Myc-repressed genes with genes that are targets of polycomb repressive complexes in embryonic stem cells. Therefore, TGFβ-dependent senescence is associated with gene expression patterns indicative of abortive cellular differentiation along several lineages.

  16. Identification of microRNAs dysregulated in cellular senescence driven by endogenous genotoxic stress

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    Nidadavolu, Lolita S.; Niedernhofer, Laura J.; Khan, Saleem A.

    2013-01-01

    XFE progeroid syndrome, a disease of accelerated aging caused by deficiency in the DNA repair endonuclease XPF-ERCC1, is modeled by Ercc1 knockout and hypomorphic mice. Tissues and primary cells from these mice senesce prematurely, offering a unique opportunity to identify factors that regulate senescence and aging. We compared microRNA (miRNA) expression in Ercc1−/− primary mouse embryonic fibroblasts (MEFs) and wild-type (WT) MEFs in different growth conditions to identify miRNAs that drive cellular senescence. Microarray analysis showed three differentially expressed miRNAs in passage 7 (P7) Ercc1−/− MEFs grown at 20% O2 compared to Ercc1−/− MEFs grown at 3% O2. Thirty-six differentially expressed miRNAs were identified in Ercc1−/− MEFs at P7 compared to early passage (P3) in 3% O2. Eight of these miRNAs (miR-449a, miR-455*, miR-128, miR-497, miR-543, miR-450b-3p, miR-872 and miR-10b) were similarly downregulated in the liver of progeroid Ercc1−/Δ and old WT mice compared to adult WT mice, a tissue that senesces with aging. Three miRNAs (miR-449a, miR-455* and miR-128) were also downregulated in Ercc1−/Δ and WT old mice kidneys compared to young WT mice. We also discovered that the miRNA expression regulator Dicer is significantly downregulated in tissues of old mice and late passage cells compared to young controls. Collectively these results support the conclusion that the miRNAs identified may play an important role in staving off cellular senescence and their altered expression could be indicative of aging. PMID:23852002

  17. The interplay between p16 serine phosphorylation and arginine methylation determines its function in modulating cellular apoptosis and senescence.

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    Lu, Yang; Ma, Wenlong; Li, Zhongwei; Lu, Jun; Wang, Xiuli

    2017-01-25

    Cyclin-dependent kinase inhibitor p16(INK4a) (p16) primarily functions as a negative regulator of the retinoblastoma protein (Rb) -E2F pathway, thus plays critical role in cell cycle progression, cellular senescence and apoptosis. In this study, we showed that the methylation of Arg 138 and the phosphorylation of Ser 140 on p16 were critical for the control of cell proliferation and apoptosis. Compared to wild type p16, mutant p16R138K possessed improved function in preventing cell proliferation and inducing apoptosis, while the Ser 140 mutation (p16S140A) exhibited the opposite alteration. We also demonstrated that H2O2 was able to induce the phosphorylation of p16, which facilitated the interaction between CDK4 (Cyclin-dependent protein kinase) and p16, in 293T (human emborynic kidney) cells. Furthermore, the elevated arginine methylation in p16S140A mutant and increased serine phosphorylation in p16R138K mutant suggest that a antagonizing mechanism coordinating Arg 138 methylation and Ser 140 phosphorylation to regulates p16 function as well as cellular apoptosis and senescence. These findings will therefore contribute to therapeutic treatment for p16-related gene therapy by providing theoretical and experimental evidence.

  18. Redox markers for drought-induced nodule senescence, a process occurring after drought-induced senescence of the lowest leaves in soybean (Glycine max).

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    Marquez-Garcia, Belén; Shaw, Daniel; Cooper, James William; Karpinska, Barbara; Quain, Marian Dorcas; Makgopa, Eugene Matome; Kunert, Karl; Foyer, Christine Helen

    2015-09-01

    Water is an increasingly scarce resource that limits crop productivity in many parts of the world, and the frequency and severity of drought are predicted to increase as a result of climate change. Improving tolerance to drought stress is therefore important for maximizing future crop yields. The aim of this study was to compare the effects of drought on soybean (Glycine max) leaves and nodules in order to define phenotypic markers and changes in cellular redox state that characterize the stress response in different organs, and to characterize the relationships between leaf and nodule senescence during drought. Leaf and crown nodule metabolite pools were measured together with leaf and soil water contents, and leaf chlorophyll, total protein contents and chlorophyll a fluorescence quenching parameters in nodulated soybeans that were grown under either well-watered conditions or deprived of water for up to 21 d. Ureides, ascorbate, protein, chlorophyll and the ratios of variable chlorophyll a fluorescence (Fv') to maximal chlorophyll a fluorescence (Fm') fell to levels below detection in the oldest leaves after 21 d of drought. While these drought-induced responses were not observed in the youngest leaf ranks, the Fv'/Fm' ratios, pyridine nucleotide levels and the reduction state of the ascorbate pool were lower in all leaf ranks after 21 d of drought. In contrast to leaves, total nodule protein, pyridine nucleotides, ureides, ascorbate and glutathione contents increased as a result of the drought treatment. However, the nodule ascorbate pool was significantly less reduced as a result of drought. Higher levels of transcripts encoding two peroxiredoxins were detected in nodules exposed to drought stress but senescence-associated transcripts and other mRNAs encoding redox-related proteins were similar under both conditions. While the physiological impact of the drought was perceived throughout the shoot, stress-induced senescence occurred only in the oldest

  19. BAF180 regulates cellular senescence and hematopoietic stem cell homeostasis through p21.

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    Lee, Hyemin; Dai, Fangyan; Zhuang, Li; Xiao, Zhen-Dong; Kim, Jongchan; Zhang, Yilei; Ma, Li; You, M James; Wang, Zhong; Gan, Boyi

    2016-04-12

    BAF180 (also called PBRM1), a subunit of the SWI/SNF complex, plays critical roles in the regulation of chromatin remodeling and gene transcription, and is frequently mutated in several human cancers. However, the role of mammalian BAF180 in tumor suppression and tissue maintenance in vivo remains largely unknown. Here, using a conditional somatic knockout approach, we explored the cellular and organismal functions of BAF180 in mouse. BAF180 deletion in primary mouse embryonic fibroblasts (MEFs) triggers profound cell cycle arrest, premature cellular senescence, without affecting DNA damage response or chromosomal integrity. While somatic deletion of BAF180 in adult mice does not provoke tumor development, BAF180 deficient mice exhibit defects in hematopoietic system characterized by progressive reduction of hematopoietic stem cells (HSCs), defective long-term repopulating potential, and hematopoietic lineage developmental aberrations. BAF180 deletion results in elevated p21 expression in both MEFs and HSCs. Mechanistically, we showed that BAF180 binds to p21 promoter, and BAF180 deletion enhances the binding of modified histones associated with transcriptional activation on p21 promoter. Deletion of p21 rescues cell cycle arrest and premature senescence in BAF180 deficient MEFs, and partially rescues hematopoietic defects in BAF180 deficient mice. Together, our study identifies BAF180 as a critical regulator of cellular senescence and HSC homeostasis, which is at least partially regulated through BAF180-mediated suppression of p21 expression. Our results also suggest that senescence triggered by BAF180 inactivation may serve as a failsafe mechanism to restrain BAF180 deficiency-associated tumor development, providing a conceptual framework to further understand BAF180 function in tumor biology.

  20. Induction of cellular senescence by doxorubicin is associated with upregulated miR-375 and induction of autophagy in K562 cells.

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    Ming-Yu Yang

    Full Text Available BACKGROUND: Cellular senescence is a specialized form of growth arrest that is generally irreversible. Upregulated p16, p53, and p21 expression and silencing of E2F target genes have been characterized to promote the establishment of senescence. It can be further aided by the transcriptional repression of proliferation-associated genes by the action of HP1γ, HMGA, and DNMT proteins to produce a repressive chromatin environment. Therefore, senescence has been suggested to functions as a natural brake for tumor development and plays a critical role in tumor suppression and aging. METHODOLOGY/PRINCIPAL FINDINGS: An in vitro senescence model has been established by using K562 cells treated with 50 nM doxorubicin (DOX. Since p53 and p16 are homozygously deleted in the K562 cells, the DOX-induced senescence in K562 cells ought to be independent of p53 and p16-pRb pathways. Indeed, no change in the expression of the typical senescence-associated premalignant cell markers in the DOX-induced senescent K562 cells was found. MicroRNA profiling revealed upregulated miR-375 in DOX-induced senescent K562 cells. Treatment with miR-375 inhibitor was able to reverse the proliferation ability suppressed by DOX (p<0.05 and overexpression of miR-375 suppressed the normal proliferation of K562 cells. Upregulated miR-375 expression was associated with downregulated expression of 14-3-3zeta and SP1 genes. Autophagy was also investigated since DOX treatment was able to induce cells entering senescence and eventually lead to cell death. Among the 24 human autophagy-related genes examined, a 12-fold increase of ATG9B at day 4 and a 20-fold increase of ATG18 at day 2 after DOX treatment were noted. CONCLUSIONS/SIGNIFICANCE: This study has demonstrated that in the absence of p53 and p16, the induction of senescence by DOX was associated with upregulation of miR-375 and autophagy initiation. The anti-proliferative function of miR-375 is possibly exerted, at least in part

  1. El nucléolo como un regulador del envejecimiento celular The nucleolus as a regulator of cellular senescence

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    María Rosete

    2007-04-01

    Full Text Available El nucléolo, considerado únicamente como el sitio de síntesis de los ribosomas, actualmente representa una estructura nuclear dinámica que participa en la regulación de importantes procesos celulares. Numerosas evidencias han demostrado que el envejecimiento celular es una de las diversas funciones que son controladas por el nucléolo. Las mutaciones en las proteínas de localización nucleolar promueven el envejecimiento prematuro en levaduras y humanos. La carencia de represión en la transcripción de genes que codifican para el ARNr que se encuentran dañados, y las mutaciones en las helicasas del ADN encargadas de minimizar la formación de círculos extra-cromosómicos del ADN que codifica para el ARNr, provocan modificaciones en la estructura del nucléolo e inducen envejecimiento prematuro en levaduras. De igual manera, en los humanos la carencia de las helicasas del ADN localizadas en el nucléolo y que participan en el mantenimiento de la integridad genómica, favorecen el desarrollo de aquellas enfermedades asociadas con el envejecimiento acelerado. Además, la presencia de algunos componentes de la telomerasa en el nucléolo, indica que parte de la biosíntesis de esta enzima se realiza en esta estructura nuclear, sugiriendo una conexión entre el nucléolo y la síntesis de los telómeros en la regulación del envejecimiento celular. Por otra parte, el nucléolo secuestra proteínas para regular su actividad biológica durante el inicio o término de la vida replicativa celular.The nucleolus has been considered originally only as the site for the ribosome synthesis, but now it is well known that it represents a dynamic nuclear structure involved in important cellular processes. Several evidences have demonstrated that the nucleolus regulates the cellular senescence. Specific mutations on the DNAs codifying for nucleolar proteins induced premature senescence from yeast to human. The failure to repress the genes transcription

  2. Ageing induced vascular smooth muscle cell senescence in atherosclerosis.

    Science.gov (United States)

    Uryga, Anna K; Bennett, Martin R

    2016-04-15

    Atherosclerosis is a disease of ageing in that its incidence and prevalence increase with age. However, atherosclerosis is also associated with biological ageing, manifest by a number of typical hallmarks of ageing in the atherosclerotic plaque. Thus, accelerated biological ageing may be superimposed on the effects of chronological ageing in atherosclerosis. Tissue ageing is seen in all cells that comprise the plaque, but particularly in vascular smooth muscle cells (VSMCs). Hallmarks of ageing include evidence of cell senescence, DNA damage (including telomere attrition), mitochondrial dysfunction, a pro-inflammatory secretory phenotype, defects in proteostasis, epigenetic changes, deregulated nutrient sensing, and exhaustion of progenitor cells. In this model, initial damage to DNA (genomic, telomeric, mitochondrial and epigenetic changes) results in a number of cellular responses (cellular senescence, deregulated nutrient sensing and defects in proteostasis). Ultimately, ongoing damage and attempts at repair by continued proliferation overwhelm reparative capacity, causing loss of specialised cell functions, cell death and inflammation. This review summarises the evidence for accelerated biological ageing in atherosclerosis, the functional consequences of cell ageing on cells comprising the plaque, and the causal role that VSMC senescence plays in atherogenesis. © 2015 The Authors. The Journal of Physiology © 2015 The Physiological Society.

  3. Apolipoprotein J/Clusterin is a novel structural component of human erythrocytes and a biomarker of cellular stress and senescence.

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    Marianna H Antonelou

    Full Text Available BACKGROUND: Secretory Apolipoprotein J/Clusterin (sCLU is a ubiquitously expressed chaperone that has been functionally implicated in several pathological conditions of increased oxidative injury, including aging. Nevertheless, the biological role of sCLU in red blood cells (RBCs remained largely unknown. In the current study we identified sCLU as a component of human RBCs and we undertook a detailed analysis of its cellular topology. Moreover, we studied the erythrocytic membrane sCLU content during organismal aging, in conditions of increased organismal stress and accelerated RBCs senescence, as well as during physiological in vivo cellular senescence. METHODOLOGY/PRINCIPAL FINDINGS: By using a combination of molecular, biochemical and high resolution microscopical methods we found that sCLU is a novel structural component of RBCs extra- and intracellular plasma membrane and cytosol. We observed that the RBCs membrane-associated sCLU decreases during organismal aging or exposure to acute stress (e.g. smoking, in patients with congenital hemolytic anemia, as well as during RBCs in vivo senescence. In all cases, sCLU reduction paralleled the expression of typical cellular senescence, redox imbalance and erythrophagocytosis markers which are also indicative of the senescence- and oxidative stress-mediated RBCs membrane vesiculation. CONCLUSIONS/SIGNIFICANCE: We propose that sCLU at the mature RBCs is not a silent remnant of the erythroid precursors, but an active component being functionally implicated in the signalling mechanisms of cellular senescence and oxidative stress-responses in both healthy and diseased organism. The reduced sCLU protein levels in the RBCs membrane following cell exposure to various endogenous or exogenous stressors closely correlates to the levels of cellular senescence and redox imbalance markers, suggesting the usefulness of sCLU as a sensitive biomarker of senescence and cellular stress.

  4. Premature lung aging and cellular senescence in the pathogenesis of idiopathic pulmonary fibrosis and COPD/emphysema.

    Science.gov (United States)

    Chilosi, Marco; Carloni, Angelo; Rossi, Andrea; Poletti, Venerino

    2013-09-01

    Different anatomic and physiological changes occur in the lung of aging people that can affect pulmonary functions, and different pulmonary diseases, including deadly diseases such as chronic obstructive pulmonary disease (COPD)/emphysema and idiopathic pulmonary fibrosis (IPF), can be related to an acceleration of the aging process. The individual genetic background, as well as exposure to a variety of toxic substances (cigarette smoke in primis) can contribute significantly to accelerating pulmonary senescence. Premature aging can impair lung function by different ways: by interfering specifically with tissue repair mechanisms after damage, thus perturbing the correct crosstalk between mesenchymal and epithelial components; by inducing systemic and/or local alteration of the immune system, thus impairing the complex mechanisms of lung defense against infections; and by stimulating a local and/or systemic inflammatory condition (inflammaging). According to recently proposed pathogenic models in COPD and IPF, premature cellular senescence likely affects distinct progenitors cells (mesenchymal stem cells in COPD, alveolar epithelial precursors in IPF), leading to stem cell exhaustion. In this review, the large amount of data supporting this pathogenic view are discussed, with emphasis on the possible molecular and cellular mechanisms leading to the severe parenchymal remodeling that characterizes, in different ways, these deadly diseases.

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

    Institute of Scientific and Technical Information of China (English)

    SCHMITT Estelle; PAQUET Claudie; BEAUCHEMIN Myriam; BERTRAND Richard

    2007-01-01

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

  6. Simvastatin rises reactive oxygen species levels and induces senescence in human melanoma cells by activation of p53/p21 pathway

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    Guterres, Fernanda Augusta de Lima Barbosa; Martinez, Glaucia Regina; Rocha, Maria Eliane Merlin; Winnischofer, Sheila Maria Brochado, E-mail: sheilambw@ufpr.br

    2013-11-15

    Recent studies demonstrated that simvastatin has antitumor properties in several types of cancer cells, mainly by inducing apoptosis and inhibiting growth. The arrest of proliferation is a feature of cellular senescence; however, the occurrence of senescence in melanoma cells upon simvastatin treatment has not been investigated until now. Our results demonstrated that exposure of human metastatic melanoma cells (WM9) to simvastatin induces a senescent phenotype, characterized by G1 arrest, positive staining for senescence-associated β-galactosidase assay, and morphological changes. Also, the main pathways leading to cell senescence were examined in simvastatin-treated human melanoma cells, and the expression levels of phospho-p53 and p21 were upregulated by simvastatin, suggesting that cell cycle regulators and DNA damage pathways are involved in the onset of senescence. Since simvastatin can act as a pro-oxidant agent, and oxidative stress may be related to senescence, we measured the intracellular ROS levels in WM9 cells upon simvastatin treatment. Interestingly, we found an increased amount of intracellular ROS in these cells, which was accompanied by elevated expression of catalase and peroxiredoxin-1. Collectively, our results demonstrated that simvastatin can induce senescence in human melanoma cells by activation of p53/p21 pathway, and that oxidative stress may be related to this process. - Highlights: • Lower concentrations of simvastatin can induce senescent phenotype in melanoma cells. • Simvastatin induces senescence in human melanoma cells via p53/p21 pathway. • Senescent phenotype is related with increased intracellular ROS. • Partial detoxification of ROS by catalase/peroxiredoxin-1 could lead cells to senescence rather than apoptosis.

  7. Standardized Kaempferia parviflora Extract Inhibits Intrinsic Aging Process in Human Dermal Fibroblasts and Hairless Mice by Inhibiting Cellular Senescence and Mitochondrial Dysfunction

    Directory of Open Access Journals (Sweden)

    Ji-Eun Park

    2017-01-01

    Full Text Available Intrinsic skin aging is a complex biological phenomenon mainly caused by cellular senescence and mitochondrial dysfunction. This study evaluated the inhibitory effect of Kaempferia parviflora Wall ex. Baker ethanol extract (KPE on H2O2-stimulated cellular senescence and mitochondrial dysfunction both in vitro and in vivo. KPE significantly increased cell growth and suppressed senescence-associated β-galactosidase activation. KPE inhibited the expression of cell-cycle inhibitors (p53, p21, p16, and pRb and stimulated the expression of cell-cycle activators (E2F1 and E2F2. H2O2-induced hyperactivation of the phosphatidylinositol 3-kinase/protein kinase B (AKT signaling pathway was suppressed by KPE through regulated expression of forkhead box O3a (FoxO3a and mammalian target of rapamycin (mTOR. KPE attenuated inflammatory mediators (interleukin-6 (IL-6, IL-8, nuclear factor kappa B (NF-κB, and cyclooxygenase-2 (COX-2 and increased the mRNA expression of PGC-1α, ERRα, NRF1, and Tfam, which modulate mitochondrial biogenesis and function. Consequently, reduced ATP levels and increased ROS level were also reversed by KPE treatment. In hairless mice, KPE inhibited wrinkle formation, skin atrophy, and loss of elasticity by increasing the collagen and elastic fibers. The results indicate that KPE prevents intrinsic aging process in hairless mice by inhibiting cellular senescence and mitochondrial dysfunction, suggesting its potential as a natural antiaging agent.

  8. Standardized Kaempferia parviflora Extract Inhibits Intrinsic Aging Process in Human Dermal Fibroblasts and Hairless Mice by Inhibiting Cellular Senescence and Mitochondrial Dysfunction.

    Science.gov (United States)

    Park, Ji-Eun; Woo, Seon Wook; Kim, Mi-Bo; Kim, Changhee; Hwang, Jae-Kwan

    2017-01-01

    Intrinsic skin aging is a complex biological phenomenon mainly caused by cellular senescence and mitochondrial dysfunction. This study evaluated the inhibitory effect of Kaempferia parviflora Wall ex. Baker ethanol extract (KPE) on H2O2-stimulated cellular senescence and mitochondrial dysfunction both in vitro and in vivo. KPE significantly increased cell growth and suppressed senescence-associated β-galactosidase activation. KPE inhibited the expression of cell-cycle inhibitors (p53, p21, p16, and pRb) and stimulated the expression of cell-cycle activators (E2F1 and E2F2). H2O2-induced hyperactivation of the phosphatidylinositol 3-kinase/protein kinase B (AKT) signaling pathway was suppressed by KPE through regulated expression of forkhead box O3a (FoxO3a) and mammalian target of rapamycin (mTOR). KPE attenuated inflammatory mediators (interleukin-6 (IL-6), IL-8, nuclear factor kappa B (NF-κB), and cyclooxygenase-2 (COX-2)) and increased the mRNA expression of PGC-1α, ERRα, NRF1, and Tfam, which modulate mitochondrial biogenesis and function. Consequently, reduced ATP levels and increased ROS level were also reversed by KPE treatment. In hairless mice, KPE inhibited wrinkle formation, skin atrophy, and loss of elasticity by increasing the collagen and elastic fibers. The results indicate that KPE prevents intrinsic aging process in hairless mice by inhibiting cellular senescence and mitochondrial dysfunction, suggesting its potential as a natural antiaging agent.

  9. Telomere Fragment Induced Amnion Cell Senescence: A Contributor to Parturition?

    Science.gov (United States)

    Polettini, Jossimara; Behnia, Faranak; Taylor, Brandie D.; Saade, George R.; Taylor, Robert N.; Menon, Ramkumar

    2015-01-01

    Oxidative stress (OS)-induced senescence of the amniochorion has been associated with parturition at term. We investigated whether telomere fragments shed into the amniotic fluid (AF) correlated with labor status and tested if exogenous telomere fragments (T-oligos) could induce human and murine amnion cell senescence. In a cross-sectional clinical study, AF telomere fragment concentrations quantitated by a validated real-time PCR assay were higher in women in labor at term compared to those not in labor. In vitro treatment of primary human amnion epithelial cells with 40 μM T-oligos ([TTAGGG]2) that mimic telomere fragments, activated p38MAPK, produced senescence-associated (SA) β-gal staining and increased interleukin (IL)-6 and IL-8 production compared to cells treated with complementary DNA sequences (Cont-oligos, [AATCCC]2). T-oligos injected into the uteri of pregnant CD1 mice on day 14 of gestation, led to increased p38MAPK, SA-β-gal (SA β-gal) staining in murine amniotic sacs and higher AF IL-8 levels on day 18, compared to saline treated controls. In summary, term labor AF samples had higher telomere fragments than term not in labor AF. In vitro and in situ telomere fragments increased human and murine amnion p38MAPK, senescence and inflammatory cytokines. We propose that telomere fragments released from senescent fetal cells are indicative of fetal cell aging. Based on our data, these telomere fragments cause oxidative stress associated damages to the term amniotic sac and force them to release other DAMPS, which, in turn, provide a sterile immune response that may be one of the many inflammatory signals required to initiate parturition at term. PMID:26397719

  10. Cellular and Subcellular Localization of Endogenous Nitric Oxide in Young and Senescent Pea Plants12

    Science.gov (United States)

    Corpas, Francisco J.; Barroso, Juan B.; Carreras, Alfonso; Quirós, Miguel; León, Ana M.; Romero-Puertas, María C.; Esteban, Francisco J.; Valderrama, Raquel; Palma, José M.; Sandalio, Luisa M.; Gómez, Manuel; del Río, Luis A.

    2004-01-01

    The cellular and subcellular localization of endogenous nitric oxide (NO˙) in leaves from young and senescent pea (Pisum sativum) plants was studied. Confocal laser scanning microscopy analysis of pea leaf sections with the fluorescent probe 4,5-diaminofluorescein diacetate revealed that endogenous NO˙ was mainly present in vascular tissues (xylem and phloem). Green fluorescence spots were also detected in the epidermal cells, palisade and spongy mesophyll cells, and guard cells. In senescent leaves, NO˙ generation was clearly reduced in the vascular tissues. At the subcellular level, by electron paramagnetic resonance spectroscopy with the spin trap Fe(MGD)2 and fluorometric analysis with 4,5-diaminofluorescein diacetate, NO˙ was found to be an endogenous metabolite of peroxisomes. The characteristic three-line electron paramagnetic resonance spectrum of NO˙, with g = 2.05 and aN = 12.8 G, was detected in peroxisomes. By fluorometry, NO˙ was also found in these organelles, and the level measured of NO˙ was linearly dependent on the amount of peroxisomal protein. The enzymatic production of NO˙ from l-Arg (nitric oxide synthase [NOS]-like activity) was measured by ozone chemiluminiscence. The specific activity of peroxisomal NOS was 4.9 nmol NO˙ mg−1 protein min−1; was strictly dependent on NADPH, calmodulin, and BH4; and required calcium. In senescent pea leaves, the NOS-like activity of peroxisomes was down-regulated by 72%. It is proposed that peroxisomal NO˙ could be involved in the process of senescence of pea leaves. PMID:15347796

  11. Western-type diet induces senescence, modifies vascular function in non-senescence mice and triggers adaptive mechanisms in senescent ones.

    Science.gov (United States)

    Onetti, Yara; Jiménez-Altayó, Francesc; Heras, Magda; Vila, Elisabet; Dantas, Ana Paula

    2013-12-01

    The effects of high-fat diet ingestion on senescence-induced modulation of contractile responses to phenylephrine (Phe) were determined in aortas of senescence-accelerated (SAMP8) and non-senescent (SAMR1) mice fed (8weeks) a Western-type high-fat diet (WD). Increased levels of senescence-associated β-galactosidase staining were found in aortas of SAMP8 and SAMR1 with WD. In SAMR1, WD did not modify Phe contraction in spite of inducing major changes in the mechanisms of regulation of contractile responses. Although WD increased NAD(P)H-oxidase-derived O2(-) and augmented peroxynitrite formation, we found an increase of inducible NOS (iNOS)-derived NO production which may contribute to maintain Phe contraction in SAMR1 WD. On SAMP8, WD significantly decreased Phe-induced contractions when compared with SAMP8 under normal chow. This response was not dependent on changes of NOS expression, but rather as consequence of increased antioxidant capacity by superoxide dismutase (SOD1). A similar constrictor influence from cyclooxygenase (COX) pathway on Phe responses was found in SAMR1 and SAMP8 ND. However, WD removed that influence on SAMR1, and produced a switch in the balance from a vasoconstrictor to a vasodilator component in SAMP8. These results were associated to the increased COX-2 expression, suggesting that a COX-2-derived vasodilator prostaglandin may contribute to the vascular adaptations after WD intake. Taken together, our data suggest that WD plays a detrimental role in the vasculature of non-senescent mice by increasing pro-inflammatory (iNOS) and pro-oxidative signaling pathways and may contribute to increase vascular senescence. In senescent vessels, however, WD triggers different intrinsic compensatory alterations which include increase of antioxidant activity by SOD1 and vasodilator prostaglandin production via COX-2. © 2013.

  12. Sodium Valproate Induces Cell Senescence in Human Hepatocarcinoma Cells

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    Hong-Mei An

    2013-12-01

    Full Text Available Hepatocarcinogenesis is associated with epigenetic changes, including histone deacetylases (HDACs. Epigenetic modulation by HDAC inhibition is a potentially valuable approach for hepatocellular carcinoma treatment. In present study, we evaluated the anticancer effects of sodium valproate (SVP, a known HDAC inhibitor, in human hepatocarcinoma cells. The results showed SVP inhibited the proliferation of Bel-7402 cells in a dose-dependent manner. Low dose SVP treatment caused a large and flat morphology change, positive SA-β-gal staining, and G0/G1 phase cell cycle arrest in human hepatocarcinoma cells. Low dose SVP treatment also increased acetylation of histone H3 and H4 on p21 promoter, accompanied by up-regulation of p21 and down-regulation of RB phosphorylation. These observations suggested that a low dose of SVP could induce cell senescence in hepatocarcinoma cells, which might correlate with hyperacetylation of histone H3 and H4, up-regulation of p21, and inhibition of RB phosphorylation. Since the effective concentration inducing cell senescence in hepatocarcinoma cells is clinically available, whether a clinical dose of SVP could induce cell senescence in clinical hepatocarcinoma is worthy of further study.

  13. Resveratrol Induced Premature Senescence Is Associated with DNA Damage Mediated SIRT1 and SIRT2 Down-Regulation.

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    Mehtap Kilic Eren

    Full Text Available The natural polyphenolic compound resveratrol (3,4,5-trihydroxy-trans-stilbene has broad spectrum health beneficial activities including antioxidant, anti-inflammatory, anti-aging, anti-cancer, cardioprotective, and neuroprotective effects. Remarkably, resveratrol also induces apoptosis and cellular senescence in primary and cancer cells. Resveratrol's anti-aging effects both in vitro and in vivo attributed to activation of a (NAD-dependent histone deacetylase family member sirtuin-1 (SIRT1 protein. In mammals seven members (SIRT1-7 of sirtuin family have been identified. Among those, SIRT1 is the most extensively studied with perceptive effects on mammalian physiology and suppression of the diseases of aging. Yet no data has specified the role of sirtuins, under conditions where resveratrol treatment induces senescence. Current study was undertaken to investigate the effects of resveratrol in human primary dermal fibroblasts (BJ and to clarify the role of sirtuin family members in particular SIRT1 and SIRT2 that are known to be involved in cellular stress responses and cell cycle, respectively. Here, we show that resveratrol decreases proliferation of BJ cells in a time and dose dependent manner. In addition the increase in senescence associated β-galactosidase (SA-β-gal activity and methylated H3K9-me indicate the induction of premature senescence. A significant increase in phosphorylation of γ-H2AX, a surrogate of DNA double strand breaks, as well as in levels of p53, p21CIP1 and p16INK4A is also detected. Interestingly, at concentrations where resveratrol induced premature senescence we show a significant decrease in SIRT1 and SIRT2 levels by Western Blot and quantitative RT-PCR analysis. Conversely inhibition of SIRT1 and SIRT2 via siRNA or sirtinol treatment also induced senescence in BJ fibroblasts associated with increased SA-β-gal activity, γ-H2AX phosphorylation and p53, p21CIP1 and p16INK4A levels. Interestingly DNA damaging

  14. Active Degradation Explains the Distribution of Nuclear Proteins during Cellular Senescence.

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    Enrico Giampieri

    Full Text Available The amount of cellular proteins is a crucial parameter that is known to vary between cells as a function of the replicative passages, and can be important during physiological aging. The process of protein degradation is known to be performed by a series of enzymatic reactions, ranging from an initial step of protein ubiquitination to their final fragmentation by the proteasome. In this paper we propose a stochastic dynamical model of nuclear proteins concentration resulting from a balance between a constant production of proteins and their degradation by a cooperative enzymatic reaction. The predictions of this model are compared with experimental data obtained by fluorescence measurements of the amount of nuclear proteins in murine tail fibroblast (MTF undergoing cellular senescence. Our model provides a three-parameter stationary distribution that is in good agreement with the experimental data even during the transition to the senescent state, where the nuclear protein concentration changes abruptly. The estimation of three parameters (cooperativity, saturation threshold, and maximal velocity of the reaction, and their evolution during replicative passages shows that only the maximal velocity varies significantly. Based on our modeling we speculate the reduction of functionality of the protein degradation mechanism as a possible competitive inhibition of the proteasome.

  15. Active Degradation Explains the Distribution of Nuclear Proteins during Cellular Senescence.

    Science.gov (United States)

    Giampieri, Enrico; De Cecco, Marco; Remondini, Daniel; Sedivy, John; Castellani, Gastone

    2015-01-01

    The amount of cellular proteins is a crucial parameter that is known to vary between cells as a function of the replicative passages, and can be important during physiological aging. The process of protein degradation is known to be performed by a series of enzymatic reactions, ranging from an initial step of protein ubiquitination to their final fragmentation by the proteasome. In this paper we propose a stochastic dynamical model of nuclear proteins concentration resulting from a balance between a constant production of proteins and their degradation by a cooperative enzymatic reaction. The predictions of this model are compared with experimental data obtained by fluorescence measurements of the amount of nuclear proteins in murine tail fibroblast (MTF) undergoing cellular senescence. Our model provides a three-parameter stationary distribution that is in good agreement with the experimental data even during the transition to the senescent state, where the nuclear protein concentration changes abruptly. The estimation of three parameters (cooperativity, saturation threshold, and maximal velocity of the reaction), and their evolution during replicative passages shows that only the maximal velocity varies significantly. Based on our modeling we speculate the reduction of functionality of the protein degradation mechanism as a possible competitive inhibition of the proteasome.

  16. Hypoxia reoxygenation induces premature senescence in neonatal SD rat cardiomyocytes

    Institute of Scientific and Technical Information of China (English)

    Feng-xiang ZHANG; Ming-long CHEN; Qi-jun SHAN; Jian-gang ZOU; Chun CHEN; Bing YANG; Dong-jie XU; Yu JIN; Ke-jiang CAO

    2007-01-01

    Aim: To investigate whether hypoxia reoxygenation induces premature senes-cence in neonatal Sprague-Dawley (SD) rat cardiomyocytes. Methods: Cardio-myocytes were isolated from neonatal SD rat heart and identified by immunohisto-chemistry. The control cultures were incubated at 37 ℃ in a humidified atmo-sphere of 5% CO and 95% air. The hypoxic cultures were incubated in a modular incubator chamber filled with 1% O2, 5% CO2, and balance N2 for 6 h. The reoxygen-ated cultures were subjected to 1% O2 and 5% CO2 for 6 h, then 21% oxygen for 4,8, 12, 24, and 48 h, respectively. Cell proliferation was determined using bromo-deoxyuridine labeling. The ultrastructure of cardiomyocytes was observed by using an electron microscope. Β-Galactosidase activity was determined by using a senescence β-galactosidase Staining Kit. P16INK4a and telomerase reverse tran-scriptase (TERT) mRNA levels were measured by real time quantitative PCR. TERT protein expression was determined by immunohistochemistry. Telomerase activi-ties were assayed by using the Telo TAGGG Telomerase PCR ELISApplus kit. Results:The initial cultures consisted of pure cardiomyocytes identified by immunohisto-chemistry. The proportion of BrdU positive cells was reduced significantly in the hypoxia reoxygenation-treated group (P<0.01). Under the condition of hypoxia reoxygenation, mitochondrial dehydration appeared; p16'INK4a and TERT mRNA levels, β-galactosidase activity, TERT protein expression and telomerase activi-ties were all significantly increased (P<0.01 or P<0.05). Conclusion: These data indicate that premature senescence could be induced in neonatal SD rat cardiomyo-cytes exposed to hypoxia reoxygenation. Although TERT significantly increased,it could not block senescence.

  17. Novel roles of Skp2 E3 ligase in cellular senescence, cancer progression, and metastasis

    Institute of Scientific and Technical Information of China (English)

    Guocan Wang; Chia-Hsin Chan; Yuan Gao; Hui-Kuan Lin

    2012-01-01

    S-phase kinase-associated protein 2 (Skp2) belongs to the F-box protein family.It is a component of the SCF E3 ubiquitin ligase complex.Skp2 has been shown to regulate cellular proliferation by targeting several cell cycle-regulated proteins for ubiquitination and degradation,including cyclin-dependent kinase inhibitor p27.Skp2 has also been demonstrated to display an oncogenic function since its overexpression has been observed in many human cancers.This review discusses the recent discoveries on the novel roles of Skp2 in regulating cellular senescence,cancer progression,and metastasis,as well as the therapeutic potential of targeting Skp2 for human cancer treatment.

  18. Protein Kinase CK2 Regulates Cytoskeletal Reorganization during Ionizing Radiation-Induced Senescence of Human Mesenchymal Stem Cells

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    Wang, Daojing; Jang, Deok-Jin

    2009-08-21

    Human mesenchymal stem cells (hMSC) are critical for tissue regeneration. How hMSC respond to genotoxic stresses and potentially contribute to aging and cancer remain underexplored. We demonstrated that ionizing radiation induced cellular senescence of hMSC over a period of 10 days, showing a critical transition between day 3 and day 6. This was confirmed by senescence-associated beta-galactosidase (SA-{beta}-gal) staining, protein expression profiles of key cell cycle regulators (retinoblastoma (Rb) protein, p53, p21{sup waf1/Cip1}, and p16{sup INK4A}), and senescence-associated secretory phenotypes (SASPs) (IL-8, IL-12, GRO, and MDC). We observed dramatic cytoskeletal reorganization of hMSC through reduction of myosin-10, redistribution of myosin-9, and secretion of profilin-1. Using a SILAC-based phosphoproteomics method, we detected significant reduction of myosin-9 phosphorylation at Ser1943, coinciding with its redistribution. Importantly, through treatment with cell permeable inhibitors (4,5,6,7-tetrabromo-1H-benzotriazole (TBB) and 2-dimethylamino-4,5,6,7-tetrabromo-1H-benzimidazole (DMAT)), and gene knockdown using RNA interference, we identified CK2, a kinase responsible for myosin-9 phosphorylation at Ser1943, as a key factor contributing to the radiation-induced senescence of hMSC. We showed that individual knockdown of CK2 catalytic subunits CK2{alpha} and CK2{alpha}{prime} induced hMSC senescence. However, only knockdown of CK2{alpha} resulted in morphological phenotypes resembling those of radiation-induced senescence. These results suggest that CK2{alpha} and CK2{alpha}{prime} play differential roles in hMSC senescence progression, and their relative expression might represent a novel regulatory mechanism for CK2 activity.

  19. Biology of cancer and aging: a complex association with cellular senescence.

    Science.gov (United States)

    Falandry, Claire; Bonnefoy, Marc; Freyer, Gilles; Gilson, Eric

    2014-08-20

    Over the last 50 years, major improvements have been made in our understanding of the driving forces, both parallel and opposing, that lead to aging and cancer. Many theories on aging first proposed in the 1950s, including those associated with telomere biology, senescence, and adult stem-cell regulation, have since gained support from cumulative experimental evidence. These views suggest that the accumulation of mutations might be a common driver of both aging and cancer. Moreover, some tumor suppressor pathways lead to aging in line with the theory of antagonist pleiotropy. According to the evolutionary-selected disposable soma theory, aging should affect primarily somatic cells. At the cellular level, both intrinsic and extrinsic pathways regulate aging and senescence. However, increasing lines of evidence support the hypothesis that these driving forces might be regulated by evolutionary-conserved pathways that modulate energy balance. According to the hyperfunction theory, aging is a quasi-program favoring both age-related diseases and cancer that could be inhibited by the regulation of longevity pathways. This review summarizes these hypotheses, as well as the experimental data that have accumulated over the last 60 years linking aging and cancer.

  20. Dehydration induced loss of photosynthesis in Arabidopsis leaves during senescence is accompanied by the reversible enhancement in the activity of cell wall β-glucosidase.

    Science.gov (United States)

    Patro, Lichita; Mohapatra, Pranab Kishor; Biswal, Udaya Chand; Biswal, Basanti

    2014-08-01

    The physiology of loss of photosynthetic production of sugar and the consequent cellular sugar reprogramming during senescence of leaves experiencing environmental stress largely remains unclear. We have shown that leaf senescence in Arabidopsis thaliana causes a significant reduction in the rate of oxygen evolution and net photosynthetic rate (Pn). The decline in photosynthesis is further aggravated by dehydration. During dehydration, primary photochemical reaction of thylakoids and net photosynthesis decrease in parallel with the increase in water deficit. Senescence induced loss in photosynthesis is accompanied by a significant increase in the activity of cell wall hydrolyzing enzyme such as β-glucosidase associated with cell wall catabolism. The activity of this enzyme is further enhanced when the senescing leaves experience dehydration stress. It is possible that both senescence and stress separately or in combination result in the loss in photosynthesis which could be a signal for an enhancement in the activity of β-glucosidase that breaks down cell wall polysaccharides to sugar to sustain respiration for metabolic activities of plants experiencing stress. Thus dehydration response of cell wall hydrolases of senescing leaves is considered as plants' strategy to have cell wall polysaccharides as an alternative energy source for completion of energy requiring senescence process, stress survival and maintenance of recovery potential of energy deficit cells in the background of loss in photosynthesis. Withdrawal of stress (rehydration) distinctly exhibits recovery of photosynthesis and suppression of enzyme activity. Retention of the signaling for sugar reprogramming through breakdown of cell wall polysaccharides in the senescing leaves exposed to severe drought stress suggests that senescing leaves like mature ones possess potential for stress recovery. The precise mechanism of stress adaptation of senescing leaves is yet to be known. A significant

  1. Inactivation of Sag/Rbx2/Roc2 E3 Ubiquitin Ligase Triggers Senescence and Inhibits Kras-Induced Immortalization

    Directory of Open Access Journals (Sweden)

    Mingjia Tan

    2015-01-01

    Full Text Available Our recent study showed that SAG/RBX2 E3 ubiquitin ligase regulates apoptosis and vasculogenesis by promoting degradation of NOXA and NF1, and co-operates with Kras to promote lung tumorigenesis by activating NFκB and mTOR pathways via targeted degradation of tumor suppressive substrates including IκB, DEPTOR, p21 and p27. Here we investigated the role of Sag/Rbx2 E3 ligase in cellular senescence and immortalization of mouse embryonic fibroblasts (MEFs and report that Sag is required for proper cell proliferation and KrasG12D-induced immortalization. Sag inactivation by genetic deletion remarkably suppresses cell proliferation by inducing senescence, which is associated with accumulation of p16, but not p53. Mechanistically, Sag deletion caused accumulation of Jun-B, a substrate of Sag-Fbxw7 E3 ligase and a transcription factor that drives p16 transcription. Importantly, senescence triggered by Sag deletion can be largely rescued by simultaneous deletion of Cdkn2a, the p16 encoding gene, indicating its causal role. Furthermore, KrasG12D-induced immortalization can also be abrogated by Sag deletion via senescence induction, which is again rescued by simultaneous deletion of Cdkn2a. Finally, we found that Sag deletion inactivates KrasG12D activity and block the MAPK signaling pathway, together with accumulated p16, to induce senescence. Taken together, our results demonstrated that Sag is a KrasG12D-cooperating oncogene required for KrasG12D-induced immortalization and transformation, and targeting SAG-SCF E3 ligase may, therefore, have therapeutic value for senescence-based cancer treatment.

  2. Expression of a nitric oxide degrading enzyme induces a senescence programme in Arabidopsis.

    Science.gov (United States)

    Mishina, Tatiana E; Lamb, Chris; Zeier, Jürgen

    2007-01-01

    Nitric oxide (NO) has been proposed to act as a factor delaying leaf senescence and fruit maturation in plants. Here we show that expression of a NO degrading dioxygenase (NOD) in Arabidopsis thaliana initiates a senescence-like phenotype, an effect that proved to be more pronounced in older than in younger leaves. This senescence phenotype was preceded by a massive switch in gene expression in which photosynthetic genes were down-regulated, whereas many senescence-associated genes (SAGs) and the 1-aminocyclopropane-1-carboxylic acid (ACC) synthase gene ACS6 involved in ethylene synthesis were up-regulated. External fumigation of NOD plants with NO as well as environmental conditions known to stimulate endogenous NO production attenuated the induced senescence programme. For instance, both high light conditions and nitrate feeding reduced the senescence phenotype and attenuated the down-regulation of photosynthetic genes as well as the up-regulation of SAGs. Treatment of plants with the cytokinin 6-benzylaminopurin (BAP) reduced the down-regulation of photosynthesis, although it had no consistent effect on SAG expression. Metabolic changes during NOD-induced senescence comprehended increases in salicylic acid (SA) levels, accumulation of the phytoalexin camalexin and elevation of leaf gamma-tocopherol contents, all of which occurred during natural senescence in Arabidopsis leaves as well. Moreover, NO fumigation delayed the senescence process induced by darkening individual Arabidopsis Columbia-0 (Col-0) leaves. Our data thus support the notion that NO acts as a negative regulator of leaf senescence.

  3. CD9 monoclonal antibody-conjugated PEGylated liposomes for targeted delivery of rapamycin in the treatment of cellular senescence

    Science.gov (United States)

    Thuy Nguyen, Hanh; Thapa, Raj Kumar; Shin, Beom Soo; Jeong, Jee-Heon; Kim, Jae-Ryong; Yong, Chul Soon; Kim, Jong Oh

    2017-03-01

    Premature cellular senescence refers to the state of irreversible cell cycle arrest due to DNA damage or other stresses. In this study, CD9 monoclonal antibody (CD9mAb) was successfully conjugated to the surface of PEGylated liposomes for targeted delivery of rapamycin (LR-CD9mAb) to overcome senescence of CD9 receptor-overexpressing cells. LR-CD9mAb has a small particle size (143.3 ± 2.4 nm), narrow size distribution (polydispersity index: 0.220 ± 0.036), and negative zeta potential (‑14.6 ± 1.2 mV). The uptake of CD9-targeted liposomes by premature senescent human dermal fibroblasts (HDFs) was higher than that by young HDFs, as displayed by confocal microscopic images. The senescence might not be reversed by treatment with rapamycin; however, the drug promoted cell proliferation and reduced the number of cells that expressed the senescence-associated-β-galactosidase (SA-β-gal). These effects were further confirmed by cell viability, cell cycle, and Western blotting analyses. Moreover, CD9-targeted liposomes showed better anti-senescence activity, in comparison with free rapamycin or the conventional liposomal formulation, suggesting the potential application of this system in further in vivo studies.

  4. Salidroside protects human fibroblast cells from premature senescence induced by H(2)O(2) partly through modulating oxidative status.

    Science.gov (United States)

    Mao, Gen-xiang; Wang, Yan; Qiu, Qiang; Deng, Hong-bin; Yuan, Long-guo; Li, Rui-guo; Song, Dan-qing; Li, Yi-yang Yvonne; Li, Dian-dong; Wang, Zhen

    2010-01-01

    Although salidroside and salidroside-like compounds are considered as most critical constitutes needed and responsible for multiple therapeutic benefits of Rhodiola rosea L., including anti-aging, direct demonstration regarding the role of salidroside in anti-aging process is still deficient. In this study, we selected the H(2)O(2)-induced premature senescence model in human fetal lung diploid fibroblasts to investigate the protection of salidroside against aging in vitro and associated molecular mechanisms. We found that salidroside considerably reversed senescence-like phenotypes in the oxidant challenged model, including alterations of morphology, cell cycle, SA-β-gal staining, DNA damage, as well as related molecules expression such as p53, p21 and p16. The protection occurred in a dose-dependent manner, with 5μM offering best efficacy. The proposed antioxidant property of the compound was confirmed in this cellular system, and thus at least partially accounted for the protection of the compound against premature senescence. Similar protection of salidroside against replicative senescence was observed as well. Interestingly, the regulation of senescence-related molecules by salidroside involved ROS-irrelevant mechanisms in both models. This finding presents salidroside as an attractive agent with potential to retard aging and attenuate age-related diseases in humans. Copyright © 2010 Elsevier Ireland Ltd. All rights reserved.

  5. Delayed leaf senescence induces extreme drought tolerance in a flowering plant

    OpenAIRE

    Rivero, Rosa M.; Kojima, Mikiko; Gepstein, Amira; Sakakibara, Hitoshi; Mittler, Ron; Gepstein, Shimon; Blumwald, Eduardo

    2007-01-01

    Drought, the most prominent threat to agricultural production worldwide, accelerates leaf senescence, leading to a decrease in canopy size, loss in photosynthesis and reduced yields. On the basis of the assumption that senescence is a type of cell death program that could be inappropriately activated during drought, we hypothesized that it may be possible to enhance drought tolerance by delaying drought-induced leaf senescence. We generated transgenic plants expressing an isopentenyltransfera...

  6. Cisplatin-induced premature senescence with concomitant reduction of gap junctions in human fibroblasts

    Institute of Scientific and Technical Information of China (English)

    Wei ZHAO; Zhong Xiang LIN; Zhi Qian ZHANG

    2004-01-01

    To examine the role of gap junctions in cell senescence,the changes of gap junctions in cisplatin-induced premature senescence of primary cultured fibroblasts were studied and compared with the replicative senescent human fibroblasts.Dye transfer assay for gap junction function and immunofluorescent staining for connexin 43 protein distribution were done respectively. Furthermore,cytofluorimetry and DAPI fluorescence staining were performed for cell cycle and apoptosis analysis. p53 gene expression level was detected with indirect immunofluorescence. We found that cisplatin (10 mM) treatment could block cell growth cycle at G1 and induced premature senescence. The premature senescence changes included high frequency of apoptosis,elevation of p53 expression,loss of membranous gap junctions and reduction of dye-transfer capacity. These changes were comparable to the changes of replicative senescence of human fibroblasts. It was also concluded that cisplatin could induce premature senescence concomitant with inhibition of gap junctions in the fibroblasts. Loss of functional gap junctions from the cell membrane may account for the reduced intercellular communication in the premature senescent fibroblasts. The cell system we used may provide a model useful for the study of the gap junction thus promoting agents against premature senescence.

  7. Autophagy: an adaptive physiological countermeasure to cellular senescence and ischaemia/reperfusion-associated cardiac arrhythmias.

    Science.gov (United States)

    Lekli, Istvan; Haines, David Donald; Balla, Gyorgy; Tosaki, Arpad

    2017-06-01

    Oxidative stress placed on tissues that involved in pathogenesis of a disease activates compensatory metabolic changes, such as DNA damage repair that in turn causes intracellular accumulation of detritus and 'proteotoxic stress', leading to emergence of 'senescent' cellular phenotypes, which express high levels of inflammatory mediators, resulting in degradation of tissue function. Proteotoxic stress resulting from hyperactive inflammation following reperfusion of ischaemic tissue causes accumulation of proteinaceous debris in cells of the heart in ways that cause potentially fatal arrhythmias, in particular ventricular fibrillation (VF). An adaptive response to VF is occurrence of autophagy, an intracellular bulk degradation of damaged macromolecules and organelles that may restore cellular and tissue homoeostasis, improving chances for recovery. Nevertheless, depending on the type and intensity of stressors and inflammatory responses, autophagy may become pathological, resulting in excessive cell death. The present review examines the multilayered defences that cells have evolved to reduce proteotoxic stress by degradation of potentially toxic material beginning with endoplasmic reticulum-associated degradation, and the unfolded protein response, which are mechanisms for removal from the endoplasmic reticulum of misfolded proteins, and then progressing through the stages of autophagy, including descriptions of autophagosomes and related vesicular structures which process material for degradation and autophagy-associated proteins including Beclin-1 and regulatory complexes. The physiological roles of each mode of proteotoxic defence will be examined along with consideration of how emerging understanding of autophagy, along with a newly discovered regulatory cell type called telocytes, may be used to augment existing strategies for the prevention and management of cardiovascular disease. © 2016 The Authors. Journal of Cellular and Molecular Medicine published by

  8. DNA Hypomethylation and Histone Variant macroH2A1 Synergistically Attenuate Chemotherapy-Induced Senescence to Promote Hepatocellular Carcinoma Progression.

    Science.gov (United States)

    Borghesan, Michela; Fusilli, Caterina; Rappa, Francesca; Panebianco, Concetta; Rizzo, Giovanni; Oben, Jude A; Mazzoccoli, Gianluigi; Faulkes, Chris; Pata, Illar; Agodi, Antonella; Rezaee, Farhad; Minogue, Shane; Warren, Alessandra; Peterson, Abigail; Sedivy, John M; Douet, Julien; Buschbeck, Marcus; Cappello, Francesco; Mazza, Tommaso; Pazienza, Valerio; Vinciguerra, Manlio

    2016-02-01

    Aging is a major risk factor for progression of liver diseases to hepatocellular carcinoma (HCC). Cellular senescence contributes to age-related tissue dysfunction, but the epigenetic basis underlying drug-induced senescence remains unclear. macroH2A1, a variant of histone H2A, is a marker of senescence-associated heterochromatic foci that synergizes with DNA methylation to silence tumor-suppressor genes in human fibroblasts. In this study, we investigated the relationship between macroH2A1 splice variants, macroH2A1.1 and macroH2A1.2, and liver carcinogenesis. We found that protein levels of both macroH2A1 isoforms were increased in the livers of very elderly rodents and humans, and were robust immunohistochemical markers of human cirrhosis and HCC. In response to the chemotherapeutic and DNA-demethylating agent 5-aza-deoxycytidine (5-aza-dC), transgenic expression of macroH2A1 isoforms in HCC cell lines prevented the emergence of a senescent-like phenotype and induced synergistic global DNA hypomethylation. Conversely, macroH2A1 depletion amplified the antiproliferative effects of 5-aza-dC in HCC cells, but failed to enhance senescence. Senescence-associated secretory phenotype and whole-transcriptome analyses implicated the p38 MAPK/IL8 pathway in mediating macroH2A1-dependent escape of HCC cells from chemotherapy-induced senescence. Furthermore, chromatin immunoprecipitation sequencing revealed that this hepatic antisenescence state also required active transcription that could not be attributed to genomic occupancy of these histones. Collectively, our findings reveal a new mechanism by which drug-induced senescence is epigenetically regulated by macroH2A1 and DNA methylation and suggest macroH2A1 as a novel biomarker of hepatic senescence that could potentially predict prognosis and disease progression. ©2016 American Association for Cancer Research.

  9. DNA Hypomethylation and Histone Variant macroH2A1 Synergistically Attenuate Chemotherapy-Induced Senescence to Promote Hepatocellular Carcinoma Progression

    Science.gov (United States)

    Borghesan, Michela; Fusilli, Caterina; Rappa, Francesca; Panebianco, Concetta; Rizzo, Giovanni; Oben, Jude A.; Mazzoccoli, Gianluigi; Faulkes, Chris; Pata, Illar; Agodi, Antonella; Rezaee, Farhad; Minogue, Shane; Warren, Alessandra; Peterson, Abigail; Sedivy, John M.; Douet, Julien; Buschbeck, Marcus; Cappello, Francesco; Mazza, Tommaso; Pazienza, Valerio; Vinciguerra, Manlio

    2016-01-01

    Aging is a major risk factor for progression of liver diseases to hepatocellular carcinoma (HCC). Cellular senescence contributes to age-related tissue dysfunction, but the epigenetic basis underlying drug-induced senescence remains unclear.macroH2A1, a variant of histone H2A, is a marker of senescence-associated heterochromatic foci that synergizes with DNA methylation to silence tumor-suppressor genes in human fibroblasts. In this study, we investigated the relationship between macroH2A1 splice variants, macroH2A1.1 and macroH2A1.2, and liver carcinogenesis. We found that protein levels of both macroH2A1 isoforms were increased in the livers of very elderly rodents and humans, and were robust immunohistochemical markers of human cirrhosis and HCC. In response to the chemotherapeutic and DNA-demethylating agent 5-aza-deoxycytidine (5-aza-dC), transgenic expression of macroH2A1 isoforms in HCC cell lines prevented the emergence of a senescent-like phenotype and induced synergistic global DNA hypomethylation. Conversely, macroH2A1 depletion amplified the antiproliferative effects of 5-aza-dC in HCC cells, but failed to enhance senescence. Senescence-associated secretory phenotype and whole-transcriptome analyses implicated the p38 MAPK/IL8 pathway in mediating macroH2A1-dependent escape of HCC cells from chemotherapy-induced senescence. Furthermore, chromatin immunoprecipitation sequencing revealed that this hepatic antisenescence state also required active transcription that could not be attributed to genomic occupancy of these histones. Collectively, our findings reveal a new mechanism by which drug-induced senescence is epigenetically regulated by macroH2A1 and DNA methylation and suggest macroH2A1 as a novel biomarker of hepatic senescence that could potentially predict prognosis and disease progression. PMID:26772755

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

    Science.gov (United States)

    Mishra, Rachana; Kaur, Gurcharan

    2015-08-01

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

  11. Resveratrol prevents oxidative stress-induced senescence and proliferative dysfunction by activating the AMPK-FOXO3 cascade in cultured primary human keratinocytes.

    Science.gov (United States)

    Ido, Yasuo; Duranton, Albert; Lan, Fan; Weikel, Karen A; Breton, Lionel; Ruderman, Neil B

    2015-01-01

    The aging process is perceived as resulting from a combination of intrinsic factors such as changes in intracellular signaling and extrinsic factors, most notably environmental stressors. In skin, the relationship between intrinsic changes and keratinocyte function is not clearly understood. Previously, we found that increasing the activity of AMP-activated protein kinase (AMPK) suppressed senescence in hydrogen peroxide (H2O2)-treated human primary keratinocytes, a model of oxidative stress-induced cellular aging. Using this model in the present study, we observed that resveratrol, an agent that increases the activities of both AMPK and sirtuins, ameliorated two age-associated phenotypes: cellular senescence and proliferative dysfunction. In addition, we found that treatment of keratinocytes with Ex527, a specific inhibitor of sirtuin 1 (SIRT1), attenuated the ability of resveratrol to suppress senescence. In keeping with the latter observation, we noted that compared to non-senescent keratinocytes, senescent cells lacked SIRT1. In addition to these effects on H2O2-induced senescence, resveratrol also prevented the H2O2-induced decrease in proliferation (as indicated by 3H-thymidine incorporation) in the presence of insulin. This effect was abrogated by inhibition of AMPK but not SIRT1. Compared to endothelium, we found that human keratinocytes expressed relatively high levels of Forkhead box O3 (FOXO3), a downstream target of both AMPK and SIRT1. Treatment of keratinocytes with resveratrol transactivated FOXO3 and increased the expression of its target genes including catalase. Resveratrol's effects on both senescence and proliferation disappeared when FOXO3 was knocked down. Finally, we performed an exploratory study which showed that skin from humans over 50 years old had lower AMPK activity than skin from individuals under age 20. Collectively, these findings suggest that the effects of resveratrol on keratinocyte senescence and proliferation are regulated by

  12. Concurrence of replicative senescence and elevated expression of p16(INK4A) with subculture-induced but not calcium-induced differentiation in normal human oral keratinocytes.

    Science.gov (United States)

    Lee, G; Park, B S; Han, S E; Oh, J E; You, Y O; Baek, J H; Kim, G S; Min, B M

    2000-10-01

    Primary normal human oral keratinocytes (NHOKs) undergo differentiation in the presence of calcium concentrations higher than 0.15 mM in vitro, which is useful in investigating the mechanisms involved in the differentiation of epithelial cells. Serial subculture of NHOKs to the postmitotic stage also induces terminal differentiation. However, the detailed mechanisms of both differentiation processes remain substantially unknown. To investigate the molecular differences in these processes, NHOKs were induced to differentiate by exposure to 1.2 mM of calcium and by serial subculture to the postmitotic stage. To study whether the cells were induced to differentiate and to undergo replicative senescence, the amount of cellular involucrin and the expression of senescence-associated beta-galactosidase (SA-beta-gal) were measured respectively. The expression of replicative senescence-associated genes and the activity of telomerase from the differentiated cells were also determined. Both calcium treatment and serial subculture to the postmitotic stage notably elevated the cellular involucrin. The percentage of SA-beta-gal-positive cells was significantly elevated by the continued subculture, but such changes were not observed in keratinocytes exposed to calcium. The concentration of cellular p16(INK4A) protein was progressively increased by the continued subculture but was not changed by calcium treatment. On the other hand, the concentrations of cellular p53 were similar in both differentiation processes. However, telomerase activity was lost in NHOKs that had undergone differentiation by both calcium treatment and serial subculture. The results indicate that calcium-induced differentiation of NHOKs has similar characteristics to their serial subculture-induced differentiation, but that the differentiation processes are not identical, because calcium-induced differentiation does not concur with either replicative senescence or the gradually increased concentration of p16

  13. Anti-Ageing Effects of Sonchus oleraceus L. (pūhā Leaf Extracts on H2O2-Induced Cell Senescence

    Directory of Open Access Journals (Sweden)

    Zong-Quan Ou

    2015-03-01

    Full Text Available Antioxidants protect against damage from free radicals and are believed to slow the ageing process. Previously, we have reported the high antioxidant activity of 70% methanolic Sonchus oleraceus L. (Asteraceae leaf extracts. We hypothesize that S. oleraceus extracts protect cells against H2O2-induced senescence by mediating oxidative stress. Premature senescence of young WI-38 cells was induced by application of H2O2. Cells were treated with S. oleraceus extracts before or after H2O2 stress. The senescence- associated β-galactosidase (SA-β-gal activity was used to indicate cell senescence. S. oleraceus extracts showed higher cellular antioxidant activity than chlorogenic acid in WI-38 cells. S. oleraceus extracts suppressed H2O2 stress-induced premature senescence in a concentration-dependent manner. At 5 and 20 mg/mL, S. oleraceus extracts showed better or equivalent effects of reducing stress-induced premature senescence than the corresponding ascorbic acid treatments. These findings indicate the potential of S. oleraceus extracts to be formulated as an anti-ageing agent.

  14. Anti-ageing effects of Sonchus oleraceus L. (pūhā) leaf extracts on H₂O₂-induced cell senescence.

    Science.gov (United States)

    Ou, Zong-Quan; Rades, Thomas; McDowell, Arlene

    2015-03-12

    Antioxidants protect against damage from free radicals and are believed to slow the ageing process. Previously, we have reported the high antioxidant activity of 70% methanolic Sonchus oleraceus L. (Asteraceae) leaf extracts. We hypothesize that S. oleraceus extracts protect cells against H2O2-induced senescence by mediating oxidative stress. Premature senescence of young WI-38 cells was induced by application of H2O2. Cells were treated with S. oleraceus extracts before or after H2O2 stress. The senescence- associated β-galactosidase (SA-β-gal) activity was used to indicate cell senescence. S. oleraceus extracts showed higher cellular antioxidant activity than chlorogenic acid in WI-38 cells. S. oleraceus extracts suppressed H2O2 stress-induced premature senescence in a concentration-dependent manner. At 5 and 20 mg/mL, S. oleraceus extracts showed better or equivalent effects of reducing stress-induced premature senescence than the corresponding ascorbic acid treatments. These findings indicate the potential of S. oleraceus extracts to be formulated as an anti-ageing agent.

  15. A subcellular distribution of estrogen receptor-alpha is changed during artificially induced senescence of PC12 pheochromocytoma cells.

    Science.gov (United States)

    Lee, Eunju; Mun, Ga Hee; Oh, Chang Seok; Chung, Yoon Hee; Cha, Choong Lk; Lee, Young Soo; Shin, Dong Hoon

    2004-11-30

    Although estrogen has been considered as a sex hormone for decades, recent reports suggest that estrogen might modulate the development and physiological function of the brain. In addition, the subcellular localization of estrogen receptors (ERs) has shown their presence within both the perinuclear cytoplasm and nuclei, suggesting that these ERs may differ functionally. We, therefore, assayed changes in the subcellular localization of ER-alpha immunoreactivity (IR) in rat pheochromocytoma PC12 cells during the artificial senescence induced by the telomerase inhibitor, 3'-azido-3'-deoxythymidine (AZT). After 2 months of culture with AZT, PC12 cells showed morphological and biochemical characteristics of cellular senescence. In the cells showing artificial senescence, the ER-alpha IR was mainly localized within the cytoplasm, whereas in control cells, ER-alpha IR was found only in the nuclei. Since senescence was induced by AZT, which inhibits the action of telomerase whenever the cells divide, the change in subcellular distribution of ER-alpha IR may be correlated with the length of the telomere.

  16. 1,25(OH)2D3 Deficiency Induces Colon Inflammation via Secretion of Senescence-Associated Inflammatory Cytokines.

    Science.gov (United States)

    Liu, Yun; Chen, Lulu; Zhi, Chunchun; Shen, Ming; Sun, Weiwei; Miao, Dengshun; Yuan, Xiaoqin

    2016-01-01

    Epidemiological studies showed that 1,25-Dihydroxyvitamin D[1,25(OH)2D3] insufficiency appears to be associated with aging and colon cancer while underlying biological mechanisms remain largely unknown. Inflammatory bowel disease is one of the risk factors for colon cancer. In this study, we investigated whether 1,25(OH)2D3 deficiency has an impact on the colon of 25-hydroxyvitamin D 1α-hydroxylase knockout [Cyp27b1(-/-)] mice fed on a rescue diet (high calcium, phosphate, and lactose) from weaning to 10 months of age. We found that 1,25(OH)2D3 deficient mice displayed significant colon inflammation phenotypes including shortened colon length, thinned and disordered mucosal structure, and inflammatory cell infiltration. DNA damage, cellular senescence and the production of senescence-associated inflammatory cytokines were also increased significantly in the colon of Cyp27b1(-/-)mice. Furthermore, the levels of ROS in the colon were increased significantly, whereas the expression levels of antioxidative genes were down-regulated dramatically in the colon of Cyp27b1(-/-)mice. Taken together, our results demonstrated that 1,25(OH)2D3 deficiency could induce colon inflammation, which may result from increased oxidative stress and DNA damage, subsequently, induced cell senescence and overproduction of senescence-associated secretory factors. Therefore, our findings suggest that 1,25(OH)2D3 may play an important role in preventing the development and progression of colon inflammation and colon cancer.

  17. WNT16B is a new marker of cellular senescence that regulates p53 activity and the phosphoinositide 3-kinase/AKT pathway.

    Science.gov (United States)

    Binet, Romuald; Ythier, Damien; Robles, Ana I; Collado, Manuel; Larrieu, Delphine; Fonti, Claire; Brambilla, Elisabeth; Brambilla, Christian; Serrano, Manuel; Harris, Curtis C; Pedeux, Rémy

    2009-12-15

    Senescence is a tumor suppression mechanism that is induced by several stimuli, including oncogenic signaling and telomere shortening, and controlled by the p53/p21(WAF1) signaling pathway. Recently, a critical role for secreted factors has emerged, suggesting that extracellular signals are necessary for the onset and maintenance of senescence. Conversely, factors secreted by senescent cells may promote tumor growth. By using expression profiling techniques, we searched for secreted factors that were overexpressed in fibroblasts undergoing replicative senescence. We identified WNT16B, a member of the WNT family of secreted proteins. We found that WNT16B is overexpressed in cells undergoing stress-induced premature senescence and oncogene-induced senescence in both MRC5 cell line and the in vivo murine model of K-Ras(V12)-induced senescence. By small interfering RNA experiments, we observed that both p53 and WNT16B are necessary for the onset of replicative senescence. WNT16B expression is required for the full transcriptional activation of p21(WAF1). Moreover, WNT16B regulates activation of the phosphoinositide 3-kinase (PI3K)/AKT pathway. Overall, we identified WNT16B as a new marker of senescence that regulates p53 activity and the PI3K/AKT pathway and is necessary for the onset of replicative senescence.

  18. Fatty acid and sterol contents during tulip leaf senescence induced by methyl jasmonate

    Directory of Open Access Journals (Sweden)

    Marian Saniewski

    2013-12-01

    Full Text Available It has been shown previously that methyl jasmonate (JA-Me applied in lanolin paste on the bottom surface of intact tulip leaves causes a rapid and intense its senescence. The aim of this work was to study the effect of JA-Me on free and bound fatty acid and sterol contents during tulip leaf senescence. The main free and bound fatty acids of tulip leaf, in decreasing order of their abundance, were linolenic, linoleic, palmitic, oleic, stearic and myristic acids. Only the content of free linolenic acid decreased after treatment with JA-Me during visible stage of senescence. ß-Sitosterol (highest concentration, campesterol, stigmasterol and cholesterol were identified in tulip leaf. Methyl jasmonate evidently increased the level of ß-sitosterol, campesterol and stigmasterol during induced senescence. It is suggested that the increase in sterol concentrations under the influence of methyl jasmonate induced changes in membrane fluidity and permeability, which may be responsible for senescence.

  19. Cloning, expression and cellular localization of Daphnia pulex senescence-associated protein, DpSAP.

    Science.gov (United States)

    Liu, Ajing; Kong, Ling; Zhang, Mingqing; Wu, Donglei; Wang, Danli; Zhao, Yunlong

    2014-01-25

    Daphnia (water fleas) are small crustaceans that undergo an unusual switch from asexual to sexual reproduction that is dependent on environmental conditions. In this study, a senescence-associated protein (SAP) from the common freshwater species Daphnia pulex was cloned using primers based on homologous sequences and rapid amplification of cDNA ends (RACE). Real-time PCR was employed to quantify the expression of D. pulex SAP (DpSAP) in individual organisms. The role of DpSAP in the reproductive transformation was further investigated in both parthenogenetic and sexual females by using digoxin-labeled SAP RNA probes and RNA whole-mount in situ hybridization. DpSAP was more highly expressed in sexual females, indicating a role in growth and reproduction. Cellular localization studies using RNA whole-mount in situ hybridization showed specific expression in the second tentacle joints. These expression patterns suggest an important role for DpSAP in the reproductive transformation of D. pulex. Copyright © 2013 Elsevier B.V. All rights reserved.

  20. 中波紫外线诱导的提前衰老成纤维细胞上清液对人真皮成纤维细胞增殖、老化及自噬的影响%Effects of conditioned medium of prematurely senescent fibroblasts induced by ultraviolet B on cellular proliferation, aging and autophagy of human dermal fibroblasts

    Institute of Scientific and Technical Information of China (English)

    王申; 周炳荣; 骆丹; 张家安; 刘娟; 张丽超; 易飞; 吴红巾; 栗丹

    2015-01-01

    by UVB radiation at 10 mJ/cm2 once daily for 5 consecutive days.Some fibroblasts were classified into two groups:an experimental group cultured in conditioned medium of UVB-induced prematurely senescent fibroblasts,and a control group cultured in conditioned medium of normal fibroblasts.After treatment for 20 consecutive days,cell counting kit-8 (CCK8) assay and 5-ethynyl-2'.-deoxyuridine (EDU) staining were performed to evaluate cellular proliferation,flow cytometry was conducted to estimate cell cycle,β-galactosidase staining to determine the percentage of senescent cells,accridine orange staining to detect the autophagy level,and Western blot and indirect immunofluorescence assay were carried out to determine the expression level of the autophagy-related protein LC3-B.Statistical analysis was done by using a two-sample t test with the Graphpad Prism 5 software.Results Compared with the control group,the proliferative activity of fibroblasts was significantly decreased (0.831 ± 0.017 vs.0.973 ± 0.017,t =5.850,P < 0.05),while EDU staining and flow cytometry both showed a significant increase in the percentage of S-phase cells (both P < 0.05),in the experimental group.The percentage of β-galactosidase-positive fibroblasts was significantly higher in the experimental group than in the control group (25.710% ± 0.304% vs.5.257% ± 1.023%,t =19.170,P < 0.05).Accridine orange staining revealed that the red fluorescence intensity of fibroblasts was significantly lower (14.287 ± 2.269 vs.29.614 ± 2.650,t =4.390,P < 0.05),while Western blot and indirect immunofluorescence assay both showed a significant elevation in the expression level of LC3-B (both P < 0.05),in the experimental group compared with the control group.Conclusions The conditioned medium of prematurely senescent fibroblasts induced by UVB can downregulate autophagy and proliferation of fibroblasts,but accelerate their aging.

  1. Happily (n)ever after: Aging in the context of oxidative stress, proteostasis loss and cellular senescence.

    Science.gov (United States)

    Höhn, Annika; Weber, Daniela; Jung, Tobias; Ott, Christiane; Hugo, Martin; Kochlik, Bastian; Kehm, Richard; König, Jeannette; Grune, Tilman; Castro, José Pedro

    2017-04-01

    Aging is a complex phenomenon and its impact is becoming more relevant due to the rising life expectancy and because aging itself is the basis for the development of age-related diseases such as cancer, neurodegenerative diseases and type 2 diabetes. Recent years of scientific research have brought up different theories that attempt to explain the aging process. So far, there is no single theory that fully explains all facets of aging. The damage accumulation theory is one of the most accepted theories due to the large body of evidence found over the years. Damage accumulation is thought to be driven, among others, by oxidative stress. This condition results in an excess attack of oxidants on biomolecules, which lead to damage accumulation over time and contribute to the functional involution of cells, tissues and organisms. If oxidative stress persists, cellular senescence is a likely outcome and an important hallmark of aging. Therefore, it becomes crucial to understand how senescent cells function and how they contribute to the aging process. This review will cover cellular senescence features related to the protein pool such as morphological and molecular hallmarks, how oxidative stress promotes protein modifications, how senescent cells cope with them by proteostasis mechanisms, including antioxidant enzymes and proteolytic systems. We will also highlight the nutritional status of senescent cells and aged organisms (including human clinical studies) by exploring trace elements and micronutrients and on their importance to develop strategies that might increase both, life and health span and postpone aging onset. Copyright © 2017 The Authors. Published by Elsevier B.V. All rights reserved.

  2. A role for p53 in selenium-induced senescence

    Science.gov (United States)

    The tumor suppressor p53 and the ataxia-telangiectasia mutated (ATM) kinase play important roles in the senescence response to oncogene activation and DNA damage. We have previously shown that selenium-containing compounds can activate an ATM-dependent senescence response in MRC-5 normal fibroblasts...

  3. Knockdown of WHIRLY1 Affects Drought Stress-Induced Leaf Senescence and Histone Modifications of the Senescence-Associated Gene HvS40

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    Bianka Janack

    2016-09-01

    Full Text Available The plastid-nucleus located protein WHIRLY1 has been described as an upstream regulator of leaf senescence, binding to the promoter of senescence-associated genes like HvS40. To investigate the impact of WHIRLY1 on drought stress-induced, premature senescence, transgenic barley plants with an RNAi-mediated knockdown of the HvWHIRLY1 gene were grown under normal and drought stress conditions. The course of leaf senescence in these lines was monitored by physiological parameters and studies on the expression of senescence- and drought stress-related genes. Drought treatment accelerated leaf senescence in WT plants, whereas WHIRLY 1 knockdown lines (RNAi-W1 showed a stay-green phenotype. Expression of both senescence-associated and drought stress-responsive genes, was delayed in the transgenic plants. Notably, expression of transcription factors of the WRKY and NAC families, which are known to function in senescence- and stress-related signaling pathways, was affected in plants with impaired accumulation of WHIRLY1, indicating that WHIRLY1 acts as an upstream regulator of drought stress-induced senescence. To reveal the epigenetic indexing of HvS40 at the onset of drought-induced senescence in WT and RNAi-W1 lines, stress-responsive loading with histone modifications of promoter and coding sequences of HvS40 was analyzed by chromatin immunoprecipitation and quantified by qRT-PCR. In the wildtype, the euchromatic mark H3K9ac of the HvS40 gene was low under control conditions and was established in response to drought treatment, indicating the action of epigenetic mechanisms in response to drought stress. However, drought stress caused no significant increase in H3K9ac in plants impaired in accumulation of WHIRLY1. The results show that WHIRLY1 knockdown sets in motion a delay in senescence that involves all aspects of gene expression, including changes in chromatin structure.

  4. Inhibition of p21-mediated ROS accumulation can rescue p21-induced senescence

    OpenAIRE

    2002-01-01

    The cyclin-dependent kinase (CDK) inhibitor p21Waf1/Cip1/Sdi1 was identified initially as a gene induced in senescent cells and itself has been shown to cause permanent growth arrest/senescence. Reactive oxygen species (ROS), a byproduct of oxidative processes, can also induce an irreversible growth arrest similar to senescence. Here we show that p21 increased intracellular levels of ROS both in normal fibroblasts and in p53-negative cancer cells. N-acetyl-l-cysteine, an ROS inhibitor, rescue...

  5. Changes in the level and distribution of Ku proteins during cellular senescence

    Science.gov (United States)

    Seluanov, Andrei; Danek, Jacquelynn; Hause, Nola; Gorbunova, Vera

    2009-01-01

    Aging is associated with accumulation of genomic rearrangements consistent with aberrant repair of DNA breaks. We have shown previously that DNA repair by nonhomologous end joining (NHEJ) becomes less efficient and more error-prone in senescent cells. Here we show that the levels of Ku70 and Ku80 drop approximately two fold in replicatively senescent cells. Intracellular distribution of Ku also changes. In the young cells roughly half of Ku is located in the nucleus and half in the cytoplasm. In senescent cells the nuclear levels of Ku do not change, while the cytoplasmic Ku fraction disappears. Upon treatment with gamma-irradiation, in the young cells cytoplasmic Ku moved into the nuclear and membrane fractions, while no change in the Ku distribution occurred in senescent cells. Upon treatment with UVC Ku moved out of the nucleus in the young cells, while most Ku remained nuclear in senescent cells. This suggests that the nuclear Ku in senescent cells is unable to respond to DNA damage. We hypothesize that overall decline in Ku levels, changes in Ku intracellular distribution, and the loss of appropriate response of Ku to DNA damage in senescent cells contribute to the decline of NHEJ and to age-related genomic instability. PMID:17686666

  6. Preterm labor in the absence of acute histologic chorioamnionitis is characterized by cellular senescence of the chorioamniotic membranes.

    Science.gov (United States)

    Gomez-Lopez, Nardhy; Romero, Roberto; Plazyo, Olesya; Schwenkel, George; Garcia-Flores, Valeria; Unkel, Ronald; Xu, Yi; Leng, Yaozhu; Hassan, Sonia S; Panaitescu, Bogdan; Cha, Jeeyeon; Dey, Sudhansu K

    2017-08-25

    Decidual senescence has been considered a mechanism of disease for spontaneous preterm labor in the absence of severe acute inflammation. Yet, signs of cellular senescence have also been observed in the chorioamniotic membranes from women who underwent the physiological process of labor at term. We aimed to investigate whether, in the absence of acute histologic chorioamnionitis, the chorioamniotic membranes from women who underwent spontaneous preterm labor or labor at term exhibit markers of cellular senescence. Chorioamniotic membrane samples were collected from women who underwent spontaneous preterm labor or labor at term. Gestational age-matched nonlabor controls were also included. Senescence-associated genes/proteins were determined using reverse transcription quantitative polymerase chain reaction (n = 7-9 each for array; n = 26-28 each for validation), enzyme-linked immunosorbent assays (n = 7-9 each), immunoblotting (n = 6-7 each), and immunohistochemistry (n = 7-8 each). Senescence-associated β-galactosidase activity (n = 7-11 each) and telomere length (n = 15-22 each) were also evaluated. In the chorioamniotic membranes without acute histologic chorioamnionitis: (1) the expression profile of senescence-associated genes was different between the labor groups (term in labor and preterm in labor) and the nonlabor groups (term no labor and preterm no labor), yet, there were differences between the term in labor and preterm in labor groups; (2) most of the differentially expressed genes among the groups were closely related to the tumor suppressor protein 53 pathway; (3) the expression of TP53 was down-regulated in the term in labor and preterm in labor groups compared to their nonlabor counterparts; (4) the expression of CDKN1A (gene coding for p21) was up-regulated in the term in labor and preterm in labor groups compared to their nonlabor counterparts; (5) the expression of the cyclin kinase CDK2 and cyclins CCNA2, CCNB1, and CCNE1 was down

  7. Reed-Sternberg cells in Hodgkin's lymphoma present features of cellular senescence

    Science.gov (United States)

    Gopas, J; Stern, E; Zurgil, U; Ozer, J; Ben-Ari, A; Shubinsky, G; Braiman, A; Sinay, R; Ezratty, J; Dronov, V; Balachandran, S; Benharroch, D; Livneh, E

    2016-01-01

    Hodgkin's Lymphoma (HL) is one of the most prevailing malignancies in young adults. Reed–Sternberg (RS) cells in HL have distinctive large cell morphology, are characteristic of the disease and their presence is essential for diagnosis. Enlarged cells are one of the hallmarks of senescence, but whether RS cells are senescent has not been previously investigated. Here we show that RS cells have characteristics of senescent cells; RS cells in HL biopsies specifically express the senescence markers and cell cycle inhibitors p21Cip1 and p16INK4a and are negative for the proliferation marker Ki-67, suggesting that these cells have ceased to proliferate. Moreover, the RS-like cells in HL lines, stained specifically for senescence-associated β-galactosidase (SA-β-gal). Oxidative stress promoted senescence in these cells as demonstrated by their staining for p21Cip1, p16INK4a, p53 and γH2AX. Senescent cells produce copious amounts of inflammatory cytokines termed ‘senescence-associated secretory phenotype' (SASP), primarily regulated by Nuclear Factor κB (NF-κB). Indeed, we show that NF-κB activity and NF-κB-dependent cytokines production (e.g., IL-6, TNF-α, GM-CSF) were elevated in RS-like cells. Furthermore, NF-κB inhibitors, JSH-23 and curcumin reduced IL-6 secretion from RS-like cells. Thus, defining RS cells as senescent offers new insights on the origin of the proinflammatory microenvironment in HL. PMID:27831553

  8. Reed-Sternberg cells in Hodgkin's lymphoma present features of cellular senescence.

    Science.gov (United States)

    Gopas, J; Stern, E; Zurgil, U; Ozer, J; Ben-Ari, A; Shubinsky, G; Braiman, A; Sinay, R; Ezratty, J; Dronov, V; Balachandran, S; Benharroch, D; Livneh, E

    2016-11-10

    Hodgkin's Lymphoma (HL) is one of the most prevailing malignancies in young adults. Reed-Sternberg (RS) cells in HL have distinctive large cell morphology, are characteristic of the disease and their presence is essential for diagnosis. Enlarged cells are one of the hallmarks of senescence, but whether RS cells are senescent has not been previously investigated. Here we show that RS cells have characteristics of senescent cells; RS cells in HL biopsies specifically express the senescence markers and cell cycle inhibitors p21(Cip1) and p16(INK4a) and are negative for the proliferation marker Ki-67, suggesting that these cells have ceased to proliferate. Moreover, the RS-like cells in HL lines, stained specifically for senescence-associated β-galactosidase (SA-β-gal). Oxidative stress promoted senescence in these cells as demonstrated by their staining for p21(Cip1), p16(INK4a), p53 and γH2AX. Senescent cells produce copious amounts of inflammatory cytokines termed 'senescence-associated secretory phenotype' (SASP), primarily regulated by Nuclear Factor κB (NF-κB). Indeed, we show that NF-κB activity and NF-κB-dependent cytokines production (e.g., IL-6, TNF-α, GM-CSF) were elevated in RS-like cells. Furthermore, NF-κB inhibitors, JSH-23 and curcumin reduced IL-6 secretion from RS-like cells. Thus, defining RS cells as senescent offers new insights on the origin of the proinflammatory microenvironment in HL.

  9. Autophagy Protects Against Senescence and Apoptosis via the RAS-Mitochondria in High-Glucose-Induced Endothelial Cells

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    Fei Chen

    2014-04-01

    Full Text Available Backgrounds: Autophagy is an important process in the pathogenesis of diabetes and plays a critical role in maintaining cellular homeostasis. However, the autophagic response and its mechanism in diabetic vascular endothelium remain unclear. Methods and Results: We studied high-glucose-induced renin-angiotensin system (RAS-mitochondrial damage and its effect on endothelial cells. With regard to therapeutics, we investigated the beneficial effect of angiotensin-converting enzyme inhibitors (ACEIs or angiotensin II type 1 receptor blockers (ARBs against high-glucose-induced endothelial responses. High glucose activated RAS, enhanced mitochondrial damage and increased senescence, apoptosis and autophagic-responses in endothelial cells, and these effects were mimicked by using angiotensin II (Ang. The use of an ACEI or ARB, however, inhibited the negative effects of high glucose. Direct mitochondrial injury caused by carbonyl cyanide 3-chlorophenylhydrazone (CCCP resulted in similar negative effects of high glucose or Ang and abrogated the protective effects of an ACEI or ARB. Additionally, by impairing autophagy, high-glucose-induced senescence and apoptosis were accelerated and the ACEI- or ARB-mediated beneficial effects were abolished. Furthermore, increases in FragEL™ DNA Fragmentation (TUNEL-positive cells, β-galactosidase activation and the expression of autophagic biomarkers were revealed in diabetic patients and rats, and the treatment with an ACEI or ARB decreased these responses. Conclusions: These data suggest that autophagy protects against senescence and apoptosis via RAS-mitochondria in high-glucose-induced endothelial cells.

  10. Taxol-induced paraptosis-like A549 cell death is not senescence

    Science.gov (United States)

    Wang, Chao-yang; Chen, Tong-Sheng

    2011-03-01

    Our previous studies have shown that taxol, a potent anticancer agent, induces caspase-independent cell death and cytoplasmic vacuolization in human lung cancer cells. However, the mechanisms of taxol-induced cytoplasmic vacuolization are poorly understood. Cytoplasmic vacuolization have been reported to be a characteristic of cell senescence. Here, we employed confocal fluorescence microscopy imaging to study the reversibility of taxol-induced cytoplasmic vacuolization and whether taxol triggers senescence in A549 cells. We found that taxol-induced cytoplasmic vacuolization at 6 or 9 h after treatment with taxol did not decrease but increase at 24 h or 72 h after refreshing the culture medium without taxol, indicating taxol-induced cytoplasmic vacuolization is irreversible. We used SA-β-Gal (senescence-associated β-galactosidase) to assess whether taxol-induced cell death in cytoplasmic vacuolization fashion is senescence, and found that hydrogen peroxide (H2O2)-treated, but not taxol-treated cells is significantly stained by the SA-β-Gal, a senescence testing kit, indicating that the form of taxol-induced cell death is not senescence.

  11. Nitric Oxide Regulates Dark-Induced Leaf Senescence Through EIN2 in Arabidopsis

    Institute of Scientific and Technical Information of China (English)

    Yun-Han Niu; Fang-Qing Guo

    2012-01-01

    The nitric oxide (NO)-deficient mutant nos1/noa1 exhibited an early leaf senescence phenotype.ETHYLENE INSENSITIVE 2 (EIN2) was previously reported to function as a positive regulator of ethyleneinduced senescence.The aim of this study was to address the question of how NO interacts with ethylene to regulate leaf senescence by characterizing the double mutant ein2-1 nos1/noa1 (Arabidopsis thaliana).Double mutant analysis revealed that the nos1/noa1-mediated,dark-induced early senescence phenotype was suppressed by mutations in EIN2,suggesting that EIN2 is involved in nitric oxide signaling in the regulation of leaf senescence.The results showed that chlorophyll degradation in the double mutant leaves was significantly delayed.In addition,nos1/noa1-mediated impairment in photochemical efficiency and integrity of thylakoid membranes was reverted by EIN2 mutations.The rapid upregulation of the known senescence marker genes in the nos1/noa1 mutant was severely inhibited in the double mutant during leaf senescence.Interestingly,the response of dark-grown nos1/noa1 mutant seedlings to ethylene was similar to that of wild type seedlings.Taken together,our findings suggest that EIN2 is involved in the regulation of early leaf senescence caused by NO deficiency,but NO deficiency caused by NOS1/NOA1 mutations does not affect ethylene signaling.

  12. Oxidative Stress Induces Endothelial Cell Senescence via Downregulation of Sirt6

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    Rong Liu

    2014-01-01

    Full Text Available Accumulating evidence has shown that diabetes accelerates aging and endothelial cell senescence is involved in the pathogenesis of diabetic vascular complications, including diabetic retinopathy. Oxidative stress is recognized as a key factor in the induction of endothelial senescence and diabetic retinopathy. However, specific mechanisms involved in oxidative stress-induced endothelial senescence have not been elucidated. We hypothesized that Sirt6, which is a nuclear, chromatin-bound protein critically involved in many pathophysiologic processes such as aging and inflammation, may have a role in oxidative stress-induced vascular cell senescence. Measurement of Sirt6 expression in human endothelial cells revealed that H2O2 treatment significantly reduced Sirt6 protein. The loss of Sirt6 was associated with an induction of a senescence phenotype in endothelial cells, including decreased cell growth, proliferation and angiogenic ability, and increased expression of senescence-associated β-galactosidase activity. Additionally, H2O2 treatment reduced eNOS expression, enhanced p21 expression, and dephosphorylated (activated retinoblastoma (Rb protein. All of these alternations were attenuated by overexpression of Sirt6, while partial knockdown of Sirt6 expression by siRNA mimicked the effect of H2O2. In conclusion, these results suggest that Sirt6 is a critical regulator of endothelial senescence and oxidative stress-induced downregulation of Sirt6 is likely involved in the pathogenesis of diabetic retinopathy.

  13. Bradykinin inhibits oxidative stress-induced cardiomyocytes senescence via regulating redox state.

    Directory of Open Access Journals (Sweden)

    Ruolan Dong

    Full Text Available BACKGROUND: Cell senescence is central to a large body of age related pathology, and accordingly, cardiomyocytes senescence is involved in many age related cardiovascular diseases. In consideration of that, delaying cardiomyocytes senescence is of great importance to control clinical cardiovascular diseases. Previous study indicated that bradykinin (BK protected endothelial cells from senescence induced by oxidative stress. However, the effects of bradykinin on cardiomyocytes senescence remain to be elucidated. In this study, we investigated the effect of bradykinin on H2O2-induced H9C2 cells senescence. METHODS AND RESULTS: Bradykinin pretreatment decreased the senescence induced by H2O2 in cultured H9C2 cells in a dose dependent manner. Interestingly, 1 nmol/L of BK almost completely inhibited the increase in senescent cell number and p21 expression induced by H2O2. Since H2O2 induces senescence through superoxide-induced DNA damage, we also observed the DNA damage by comet assay, and BK markedly reduced DNA damage induced by H2O2, and moreover, BK treatment significantly prevented reactive oxygen species (ROS production in H9C2 cells treated with H2O2. Importantly, when co-incubated with bradykinin B2 receptor antagonist HOE-140 or eNOS inhibitor N-methyl-L-arginine acetate salt (L-NAME, the protective effects of bradykinin on H9C2 senescence were totally blocked. Furthermore, BK administration significantly prevented the increase in nicotinamide adenine dinucleotide phosphate (NADPH oxidase activity characterized by increased ROS generation and gp91 expression and increased translocation of p47 and p67 to the membrane and the decrease in superoxide dismutase (SOD activity and expression induced by H2O2 in H9C2 cells, which was dependent on BK B2 receptor mediated nitric oxide (NO release. CONCLUSIONS: Bradykinin, acting through BK B2 receptor induced NO release, upregulated antioxidant Cu/Zn-SOD and Mn-SOD activity and expression while

  14. The telomeric protein AKTIP interacts with A- and B-type lamins and is involved in regulation of cellular senescence

    Science.gov (United States)

    Burla, Romina; Carcuro, Mariateresa; Torre, Mattia La; Fratini, Federica; Crescenzi, Marco; D'Apice, Maria Rosaria; Spitalieri, Paola; Raffa, Grazia Daniela; Astrologo, Letizia; Lattanzi, Giovanna; Cundari, Enrico; Raimondo, Domenico; Biroccio, Annamaria; Gatti, Maurizio

    2016-01-01

    AKTIP is a shelterin-interacting protein required for replication of telomeric DNA. Here, we show that AKTIP biochemically interacts with A- and B-type lamins and affects lamin A, but not lamin C or B, expression. In interphase cells, AKTIP localizes at the nuclear rim and in discrete regions of the nucleoplasm just like lamins. Double immunostaining revealed that AKTIP partially co-localizes with lamin B1 and lamin A/C in interphase cells, and that proper AKTIP localization requires functional lamin A. In mitotic cells, AKTIP is enriched at the spindle poles and at the midbody of late telophase cells similar to lamin B1. AKTIP-depleted cells show senescence-associated markers and recapitulate several aspects of the progeroid phenotype. Collectively, our results indicate that AKTIP is a new player in lamin-related processes, including those that govern nuclear architecture, telomere homeostasis and cellular senescence. PMID:27512140

  15. Androgen Depletion Induces Senescence in Prostate Cancer Cells through Down-regulation of Skp2

    Directory of Open Access Journals (Sweden)

    Zuzana Pernicová

    2011-06-01

    Full Text Available Although the induction of senescence in cancer cells is a potent mechanism of tumor suppression, senescent cells remain metabolically active and may secrete a broad spectrum of factors that promote tumorigenicity in neighboring malignant cells. Here we show that androgen deprivation therapy (ADT, a widely used treatment for advanced prostate cancer, induces a senescence-associated secretory phenotype in prostate cancer epithelial cells, indicated by increases in senescence-associated β-galactosidase activity, heterochromatin protein 1β foci, and expression of cathepsin B and insulin-like growth factor binding protein 3. Interestingly, ADT also induced high levels of vimentin expression in prostate cancer cell lines in vitro and in human prostate tumors in vivo. The induction of the senescence-associated secretory phenotype by androgen depletion was mediated, at least in part, by down-regulation of S-phase kinase-associated protein 2, whereas the neuroendocrine differentiation of prostate cancer cells was under separate control. These data demonstrate a previously unrecognized link between inhibition of androgen receptor signaling, down-regulation of S-phase kinase-associated protein 2, and the appearance of secretory, tumor-promoting senescent cells in prostate tumors. We propose that ADT may contribute to the development of androgen-independent prostate cancer through modulation of the tissue microenvironment by senescent cells.

  16. Perception of Arabidopsis AtPep peptides, but not bacterial elicitors, accelerates starvation-induced senescence

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    Kay eGully

    2015-01-01

    Full Text Available Members of the AtPep group of Arabidopsis endogenous peptides have frequently been reported to induce pattern-triggered immunity and to increase resistance to diverse pathogens by amplifying the innate immune response. Here, we made the surprising observation that dark-induced leaf senescence was accelerated by the presence of Peps. Adult leaves as well as leaf discs of Col-0 wild type plants showed a Pep-triggered early onset of chlorophyll breakdown and leaf yellowing whereas pepr1 pepr2 double mutant plants were insensitive. In addition, this response was dependent on ethylene signaling and inhibited by the addition of cytokinins. Notably, addition of the bacterial elicitors flg22 or elf18, both potent inducers of pattern-triggered immunity, did not provoke an early onset of leaf senescence.Continuous darkness leads to energy deprivation and starvation and therewith promotes leaf senescence. We found that continuous darkness also strongly induced PROPEP3 transcription. Moreover, Pep-perception led to a rapid induction of PAO, APG7 and APG8a, genes indispensable for chlorophyll degradation as well as autophagy, respectively, and all three hallmarks of starvation and senescence. Notably, addition of sucrose as a source of energy inhibited the Pep-triggered early onset of senescence. In conclusion, we report that Pep-perception accelerates dark/starvation-induced senescence via an early induction of chlorophyll degradation and autophagy. This represents a novel and unique characteristic of PEPR signaling, unrelated to pattern-triggered immunity.

  17. Aging-associated oxidized albumin promotes cellular senescence and endothelial damage

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    Luna C

    2016-02-01

    Full Text Available Carlos Luna,1,* Matilde Alique,2,* Estefanía Navalmoral,2 Maria-Victoria Noci,3 Lourdes Bohorquez-Magro,2 Julia Carracedo,1 Rafael Ramírez2 1Nephrology Unit, Instituto Maimónides de Investigación Biomédica de Córdoba (IMIBIC, Reina Sofía University Hospital, Córdoba, Spain; 2Department of Systems Biology, Physiology Unit, Universidad de Alcalá, Madrid, Spain; 3Anesthesia Unit, Reina sofía University Hospital, Córdoba, Spain*These authors contributed equally to this work Abstract: Increased levels of oxidized proteins with aging have been considered a cardiovascular risk factor. However, it is unclear whether oxidized albumin, which is the most abundant serum protein, induces endothelial damage. The results of this study indicated that with aging processes, the levels of oxidized proteins as well as endothelial microparticles release increased, a novel marker of endothelial damage. Among these, oxidized albumin seems to play a principal role. Through in vitro studies, endothelial cells cultured with oxidized albumin exhibited an increment of endothelial damage markers such as adhesion molecules and apoptosis levels. In addition, albumin oxidation increased the amount of endothelial microparticles that were released. Moreover, endothelial cells with increased oxidative stress undergo senescence. In addition, endothelial cells cultured with oxidized albumin shown a reduction in endothelial cell migration measured by wound healing. As a result, we provide the first evidence that oxidized albumin induces endothelial injury which then contributes to the increase of cardiovascular disease in the elderly subjects.Keywords: elderly, oxidative stress, microparticles, vascular damage

  18. Overexpression of the DEC1 protein induces senescence in vitro and is related to better survival in esophageal squamous cell carcinoma.

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    Qing Xu

    Full Text Available Esophageal squamous cell carcinoma (ESCC is a leading cause of cancer-related death in China and has limited effective therapeutic options except for early surgery, since the underlying molecular mechanism driving its precursor lesions towards invasive ESCC is not fully understood. Cellular senescence is the state of the permanent growth arrest of a cell, and is considered as the initial barrier of tumor development. Human differentiated embryo chondrocyte expressed gene 1 (Dec1 is an important transcription factor that related to senescence. In this study, DEC1 immunohistochemical analysis was performed on tissue microarray blocks constructed from ESCC combined with adjacent precursor tissues of 241 patients. Compared with normal epithelia, DEC1 expression was significantly increased in intraepithelial neoplasia and DEC1 expression was significantly decreased in ESCC in comparison with intraepithelial neoplasia. In vitro, DEC1 overexpression induced cellular senescence, and it inhibited cell growth and colony formation in ESCC cell line EC9706. Fresh esophagectomy tissue sections from five ESCC patients were detected by immunohistochemistry of DEC1 and senescence-associated β-galactosidase (SA-β-Gal activity, and strongly positive expression of DEC1 was correlated to more senescent cells in these fresh tissue sections. Kaplan-Meier method analysis of the 241 patients revealed that DEC1 expression levels were significantly correlated with the survival of ESCC patients after surgery. The expression levels of DEC1 were also correlated with age, tumor embolus, depth of invasion of ESCC, lymph metastasis status and pTNMs. These results suggest that DEC1 overexpression in precursor lesions of ESCC is a protective mechanism by inducing cellular senescence in ESCC initiation, and DEC1 may be a potential prognostic marker of ESCC.

  19. Inhibition of Mitochondrial Cytochrome c Release and Suppression of Caspases by Gamma-Tocotrienol Prevent Apoptosis and Delay Aging in Stress-Induced Premature Senescence of Skin Fibroblasts

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    Suzana Makpol

    2012-01-01

    Full Text Available In this study, we determined the molecular mechanism of γ-tocotrienol (GTT in preventing cellular aging by focusing on its anti-apoptotic effect in stress-induced premature senescence (SIPS model of human diploid fibroblasts (HDFs. Results obtained showed that SIPS exhibited senescent-phenotypic characteristic, increased expression of senescence-associated β-galactosidase (SA β-gal and promoted G0/G1 cell cycle arrest accompanied by shortening of telomere length with decreased telomerase activity. Both SIPS and senescent HDFs shared similar apoptotic changes such as increased Annexin V-FITC positive cells, increased cytochrome c release and increased activation of caspase-9 and caspase-3 (P<0.05. GTT treatment resulted in a significant reduction of Annexin V-FITC positive cells, inhibited cytochrome c release and decreased activation of caspase-9 and caspase-3 (P<0.05. Gene expression analysis showed that GTT treatment down regulated BAX mRNA, up-regulated BCL2A1 mRNA and decreased the ratio of Bax/Bcl-2 protein expression (P<0.05 in SIPS. These findings suggested that GTT inhibits apoptosis by modulating the upstream apoptosis cascade, causing the inhibition of cytochrome c release from the mitochondria with concomitant suppression of caspase-9 and caspase-3 activation. In conclusion, GTT delays cellular senescence of human diploid fibroblasts through the inhibition of intrinsic mitochondria-mediated pathway which involved the regulation of pro- and anti-apoptotic genes and proteins.

  20. Aberrant anaplastic lymphoma kinase activity induces a p53 and Rb-dependent senescence-like arrest in the absence of detectable p53 stabilization.

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    Fiona Kate Elizabeth McDuff

    Full Text Available Anaplastic Lymphoma Kinase (ALK is a receptor tyrosine kinase aberrantly expressed in a variety of tumor types, most notably in Anaplastic Large Cell Lymphoma (ALCL where a chromosomal translocation generates the oncogenic fusion protein, Nucleophosmin-ALK (NPM-ALK. Whilst much is known regarding the mechanism of transformation by NPM-ALK, the existence of cellular defence pathways to prevent this pathological process has not been investigated. Employing the highly tractable primary murine embryonic fibroblast (MEF system we show that cellular transformation is not an inevitable consequence of NPM-ALK activity but is combated by p53 and Rb. Activation of p53 and/or Rb by NPM-ALK triggers a potent proliferative block with features reminiscent of senescence. While loss of p53 alone is sufficient to circumvent NPM-ALK-induced senescence and permit cellular transformation, sole loss of Rb permits continued proliferation but not transformation due to p53-imposed restraints. Furthermore, NPM-ALK attenuates p53 activity in an Rb and MDM2 dependent manner but this activity is not sufficient to bypass senescence. These data indicate that senescence may constitute an effective barrier to ALK-induced malignancies that ultimately must be overcome for tumor development.

  1. Connecting radiation-induced bystander effects and senescence to improve radiation response prediction.

    Science.gov (United States)

    Poleszczuk, Jan; Krzywon, Aleksandra; Forys, Urszula; Widel, Maria

    2015-05-01

    For the last two decades radiation-induced bystander effects (RIBEs) have attracted significant attention due to their possible implications for radiotherapy. However, despite extensive research, the molecular pathways associated with RIBEs are still not completely known. In the current study we investigated the role of senescence in the bystander response. Irradiated (2, 4, 6 and 8 Gy) human colorectal carcinoma cells (HCT116) with p53(+/+) (wild-type) or p53(-/-) (knockout) gene were co-incubated with nonirradiated cells of the same type. Clonogenic and senescence assays were used for both irradiated and co-incubated bystander cell populations. We also performed additional measurements on the number of remaining cells after the whole co-incubation period. For radiation doses larger than 2 Gy we observed much larger fractions of senescent cells in p53-positive populations compared to their p53-negative counterparts (15.81% vs. 3.63% in the irradiated population; 2.89% vs. 1.05% in the bystander population; 8 Gy; P bystander population; 8 Gy; P bystander population. We also extended the standard linear-quadratic radiation response model by incorporating the influence of the signals released by the senescent cells, which accurately described the radiation response in the bystander population. Our findings suggest that radiation-induced senescence might be a key player in RIBE, i.e., the strength of RIBE depends on the amount of radiation-induced senescence.

  2. Metformin and the ATM DNA damage response (DDR): accelerating the onset of stress-induced senescence to boost protection against cancer.

    Science.gov (United States)

    Menendez, Javier A; Cufí, Sílvia; Oliveras-Ferraros, Cristina; Martin-Castillo, Begoña; Joven, Jorge; Vellon, Luciano; Vazquez-Martin, Alejandro

    2011-11-01

    By activating the ataxia telangiectasia mutated (ATM)-mediated DNA Damage Response (DDR), the AMPK agonist metformin might sensitize cells against further damage, thus mimicking the precancerous stimulus that induces an intrinsic barrier against carcinogenesis. Herein, we present the new hypothesis that metformin might function as a tissue sweeper of pre-malignant cells before they gain stem cell/tumor initiating properties. Because enhanced glycolysis (the Warburg effect) plays a causal role in the gain of stem-like properties of tumor-initiating cells by protecting them from the pro-senescent effects of mitochondrial respiration-induced oxidative stress, metformin's ability to disrupt the glycolytic metabotype may generate a cellular phenotype that is metabolically protected against immortalization. The bioenergetic crisis imposed by metformin, which may involve enhanced mitochondrial biogenesis and oxidative stress, can lower the threshold for cellular senescence by pre-activating an ATM-dependent pseudo-DDR. This allows an accelerated onset of cellular senescence in response to additional oncogenic stresses. By pushing cancer cells to use oxidative phosphorylation instead of glycolysis, metformin can rescue cell surface major histocompatibility complex class I (MHC-I) expression that is downregulated by oncogenic transformation, a crucial adaptation of tumor cells to avoid the adaptive immune response by cytotoxic T-lymphocytes (CTLs). Aside from restoration of tumor immunosurveillance at the cell-autonomous level, metformin can activate a senescence-associated secretory phenotype (SASP) to reinforce senescence growth arrest, which might trigger an immune-mediated clearance of the senescent cells in a non-cell-autonomous manner. By diminishing the probability of escape from the senescence anti-tumor barrier, the net effect of metformin should be a significant decrease in the accumulation of dysfunctional, pre-malignant cells in tissues, including those with the

  3. Myeloperoxidase-derived hypochlorous acid promotes ox-LDL-induced senescence of endothelial cells through a mechanism involving β-catenin signaling in hyperlipidemia.

    Science.gov (United States)

    Liu, Wei-Qi; Zhang, Yin-Zhuang; Wu, Yan; Zhang, Jie-Jie; Li, Tin-Bo; Jiang, Tian; Xiong, Xiao-Ming; Luo, Xiu-Ju; Ma, Qi-Lin; Peng, Jun

    2015-11-27

    Myeloperoxidase (MPO)-derived product hypochlorous acid (HOCl) is able to induce cellular senescence and MPO is also expressed in endothelial cells besides the well-recognized immune cells. This study aims to clarify the association of endothelium-derived MPO with endothelial senescence in hyperlipidemia. The rats were fed with high-fat diet for 8 weeks to establish a hyperlipidemic model, which showed an increase in plasma lipids, endothelium-derived MPO expression, endothelial senescence and endothelial dysfunction concomitant with a reduction in glycogen synthase kinase 3 beta (GSK-3β) activity and phosphorylated β-catenin (p-β-catenin) level as well as an increase in β-catenin and p53 levels within the endothelium. Next, human umbilical vein endothelial cells (HUVECs) were incubated with oxidized low density lipoprotein (ox-LDL, 100 μg/ml) for 24 h to establish a senescent cell model in vitro. Consistent with the finding in vivo, ox-LDL-induced MPO expression and HUVECs senescence, accompanied by a decrease in GSK-3β activity and p-β-catenin level as well as an increase in HOCl content, β-catenin and p53 levels; these phenomena were attenuated by MPO inhibitor. Replacement of ox-LDL with HOCl could also induce HUVECs senescence and activate the β-catenin/p53 pathway. Based on these observations, we conclude that endothelium-derived MPO is upregulated in hyperlipidemic rats, which may contribute to the accelerated vascular endothelial senescence through a mechanism involving the β-catenin/p53 pathway.

  4. The interplay between p16 serine phosphorylation and arginine methylation determines its function in modulating cellular apoptosis and senescence

    OpenAIRE

    Lu, Yang; Ma, Wenlong; Li, Zhongwei; Lu, Jun; Wang, Xiuli

    2017-01-01

    Cyclin-dependent kinase inhibitor p16INK4a (p16) primarily functions as a negative regulator of the retinoblastoma protein (Rb) -E2F pathway, thus plays critical role in cell cycle progression, cellular senescence and apoptosis. In this study, we showed that the methylation of Arg 138 and the phosphorylation of Ser 140 on p16 were critical for the control of cell proliferation and apoptosis. Compared to wild type p16, mutant p16R138K possessed improved function in preventing cell proliferatio...

  5. A posttranslational modification cascade involving p38, Tip60, and PRAK mediates oncogene-induced senescence.

    Science.gov (United States)

    Zheng, Hui; Seit-Nebi, Alim; Han, Xuemei; Aslanian, Aaron; Tat, John; Liao, Rong; Yates, John R; Sun, Peiqing

    2013-06-06

    Oncogene-induced senescence is an important tumor-suppressing defense mechanism. However, relatively little is known about the signaling pathway mediating the senescence response. Here, we demonstrate that a multifunctional acetyltransferase, Tip60, plays an essential role in oncogenic ras-induced senescence. Further investigation reveals a cascade of posttranslational modifications involving p38, Tip60, and PRAK, three proteins that are essential for ras-induced senescence. Upon activation by ras, p38 induces the acetyltransferase activity of Tip60 through phosphorylation of Thr158; activated Tip60 in turn directly interacts with and induces the protein kinase activity of PRAK through acetylation of K364 in a manner that depends on phosphorylation of both Tip60 and PRAK by p38. These posttranslational modifications are critical for the prosenescent function of Tip60 and PRAK, respectively. These results have defined a signaling pathway that mediates oncogene-induced senescence, and identified posttranslational modifications that regulate the enzymatic activity and biological functions of Tip60 and PRAK.

  6. Phosphatidylinositol 3-kinase inhibitor, LY294002, induced senescence-like changes in human diploid fibroblasts

    Institute of Scientific and Technical Information of China (English)

    李淑萍; 张宗玉; 童坦君

    2003-01-01

    Objective To reveal the role of Phosphatidylinositol 3-kinases (PI3Ks) in regulating human diploid fibroblast (2BS cell) senescence as well as the possible mechanisms involved.Methods Using a PI3Ks specific inhibitor, LY294002, cell cycle, apoptosis, proliferation, senescence association β-galactosidase staining as well as senescence association CKIs, p16 INK4 and p21 Cip1 protein expressions were all measured in the low passages of 2BS cells.Results Both 25 μmol/L and 50 μmol/L concentrations of LY294002 could cause a significant decrease in cells entering into S phase, and this cell cycle of G 1 phase arrest was dose-dependent. Meanwhile, LY294002 contributed to apoptosis, caused 2BS cell growth arrest, and activated senescence association β-galactosidase (P<0.05). In addition, LY294002 could induce time-course expressions of p16 INK4 and p21 Cip1 in 2BS cell lines.Conclusions PI3Ks inhibitor LY294002 could induce senescence-like changes in 2BS cell lines. Two enescence associated CKIs,p16 INK4 and p21 Cip1, might be involved in this senescence phenotype proceeding in 2BS cell lines.

  7. Immune response to RB1-regulated senescence limits radiation-induced osteosarcoma formation

    Science.gov (United States)

    Kansara, Maya; Leong, Huei San; Lin, Dan Mei; Popkiss, Sophie; Pang, Puiyi; Garsed, Dale W.; Walkley, Carl R.; Cullinane, Carleen; Ellul, Jason; Haynes, Nicole M.; Hicks, Rod; Kuijjer, Marieke L.; Cleton-Jansen, Anne-Marie; Hinds, Philip W.; Smyth, Mark J.; Thomas, David M.

    2013-01-01

    Ionizing radiation (IR) and germline mutations in the retinoblastoma tumor suppressor gene (RB1) are the strongest risk factors for developing osteosarcoma. Recapitulating the human predisposition, we found that Rb1+/– mice exhibited accelerated development of IR-induced osteosarcoma, with a latency of 39 weeks. Initial exposure of osteoblasts to carcinogenic doses of IR in vitro and in vivo induced RB1-dependent senescence and the expression of a panel of proteins known as senescence-associated secretory phenotype (SASP), dominated by IL-6. RB1 expression closely correlated with that of the SASP cassette in human osteosarcomas, and low expression of both RB1 and the SASP genes was associated with poor prognosis. In vivo, IL-6 was required for IR-induced senescence, which elicited NKT cell infiltration and a host inflammatory response. Mice lacking IL-6 or NKT cells had accelerated development of IR-induced osteosarcomas. These data elucidate an important link between senescence, which is a cell-autonomous tumor suppressor response, and the activation of host-dependent cancer immunosurveillance. Our findings indicate that overcoming the immune response to senescence is a rate-limiting step in the formation of IR-induced osteosarcoma. PMID:24231354

  8. RESEARCH PROGRESS OF CELLULAR SENESCENCE AND SENESCENT SECRETARY PHENOTYPE IN INTERVERTEBRAL DISC DEGENERATION%细胞老化及老化表型改变在椎间盘退行性变中的研究进展

    Institute of Scientific and Technical Information of China (English)

    王锋; 郑陈静美; 吴小涛

    2012-01-01

    Objective To summarize the role of cellular senescence and senescent secretary phenotype in the intervertebral disc (IVD) degeneration. Methods Relevant articles that discussed the roles of cellular senescence in the IVD degeneration were extensively reviewed, and retrospective and comprehensive analysis was performed. The senescent phenomenon during IVD degeneration, senescent secretary phenotype of the disc cells, senescent pathways within the IVD microenvironment, as well as the anti-senescent approaches for IVD regeneration were systematically reviewed. Results During aging and degeneration, IVD cells gradually and/or prematurely undergo senescence by activating p53-p21-retinoblastoma (RB) or pl6INK4A-RB senescent pathways. The accumulation of senescent cells not only decreases the self-renewal ability of IVD, but also deteriorates the disc microenvironment by producing more inflammatory cytokines and matrix degrading enzymes. More specific senescent biomarkers are required to fully understand the phenotype change of senescent disc cells during IVD degeneration. Molecular analysis of the senescent disc cells and their intracellular signaling pathways are needed to get a safer and more efficient anti-senescence strategy for IVD regeneration. Conclusion Cellular senescence is an important mechanism by which IVD cells decrease viabil ity and degenerate biological behaviors, which provide a new thinking to understand the pathogenesis of IVD degeneration.%目的 综述细胞老化及老化表型改变在椎间盘退行性变中的研究进展. 方法 查阅椎间盘退行性变领域细胞老化相关的国内外文献并回顾分析,综述椎间盘细胞的老化现象、老化表型改变、老化信号激活与椎间盘退行性变的相互关系,评价抗老化治疗对椎间盘退行性变的修复作用. 结果 随着机体衰老与椎间盘退行性变,椎间盘细胞通过选择性地激活p53-p21-视网膜母细胞瘤(retinoblastoma,RB)或p16INK4A-RB信号

  9. Trigeminal star-like platinum complexes induce cancer cell senescence through quadruplex-mediated telomere dysfunction.

    Science.gov (United States)

    Zheng, Xiao-Hui; Mu, Ge; Zhong, Yi-Fang; Zhang, Tian-Peng; Cao, Qian; Ji, Liang-Nian; Zhao, Yong; Mao, Zong-Wan

    2016-12-01

    Two trigeminal star-like platinum complexes were synthesized to induce the formation of human telomere G-quadruplex (hTel G4) with extremely high selectivity and affinity. The induced hTel G4 activates strong telomeric DNA damage response (TDDR), resulting in telomere dysfunction and cell senescence.

  10. Ethylene production associated with petal senescence in carnation flowers is induced irrespective of the gynoecium.

    Science.gov (United States)

    Ichimura, Kazuo; Niki, Tomoko

    2014-11-15

    To clarify whether climacteric-like increases in ethylene production of senescing petals are also induced in the absence of the gynoecium in cut carnation (Dianthus caryophyllus cv. Barbara) flowers, we compared ethylene production and expression of ethylene-biosynthesis genes in detached petals and in petals, which remained on flowers (attached petals). No significant difference in longevity was observed between the attached and detached petals when held in distilled water, and both showed the inward rolling typical of senescing flowers. Treatment with silver thiosulfate complex (STS), an ethylene inhibitor, similarly delayed senescence of attached and detached petals. Climacteric-like increases in ethylene production of petals and gynoecium started on the same day, with similar bursts in attached and detached petals. Transcript levels of DcACS1 and DcACO1 were very low at harvest and increased similarly during senescence in both petal groups. Removal of the gynoecium did not significantly delay wilting of attached petals. In flowers with the gynoecium removed, the petals produced most of the ethylene while production by the other floral organs was very low, suggesting that wound-induced ethylene is not the reason for the ineffectiveness of gynoecium-removal in inhibiting flower senescence. These results indicate that ethylene biosynthesis is induced in carnation petals irrespective of the gynoecium.

  11. Reduced PKC α Activity Induces Senescent Phenotype in Erythrocytes

    Directory of Open Access Journals (Sweden)

    Rukmini B. Govekar

    2012-01-01

    Full Text Available The molecular mechanism mediating expression of senescent cell antigen-aggregated or cleaved band 3 and externalized phosphatidylserine (PS on the surface of aged erythrocytes and their premature expression in certain anemias is not completely elucidated. The erythrocytes with these surface modifications undergo macrophage-mediated phagocytosis. In this study, the role of protein kinase C (PKC isoforms in the expression of these surface modifications was investigated. Inhibition of PKC α by 30 μM rottlerin (R30 and 2.3 nM Gö 6976 caused expression of both the senescent cell marker-externalized PS measured by FACS analysis and aggregated band 3 detected by western blotting. In contrast to this observation, but in keeping with literature, PKC activation by phorbol-12-myristate-13-acetate (PMA also led to the expression of senescence markers. We explain this antithesis by demonstrating that PMA-treated cells show reduction in the activity of PKC α, thereby simulating inhibition. The reduction in PKC α activity may be attributed to the known downregulation of PMA-activated PKC α, caused by its membrane translocation and proteolysis. We demonstrate membrane translocation of PKC α in PMA-treated cells to substantiate this inference. Thus loss of PKC α activity either by inhibition or downregulation can cause surface modifications which can trigger erythrophagocytosis.

  12. Expression of Senescence-Associated microRNAs and Target Genes in Cellular Aging and Modulation by Tocotrienol-Rich Fraction

    Directory of Open Access Journals (Sweden)

    Sharon Gwee Sian Khee

    2014-01-01

    Full Text Available Emerging evidences highlight the implication of microRNAs as a posttranscriptional regulator in aging. Several senescence-associated microRNAs (SA-miRNAs are found to be differentially expressed during cellular senescence. However, the role of dietary compounds on SA-miRNAs remains elusive. This study aimed to elucidate the modulatory role of tocotrienol-rich fraction (TRF on SA-miRNAs (miR-20a, miR-24, miR-34a, miR-106a, and miR-449a and established target genes of miR-34a (CCND1, CDK4, and SIRT1 during replicative senescence of human diploid fibroblasts (HDFs. Primary cultures of HDFs at young and senescent were incubated with TRF at 0.5 mg/mL. Taqman microRNA assay showed significant upregulation of miR-24 and miR-34a and downregulation of miR-20a and miR-449a in senescent HDFs (P<0.05. TRF reduced miR-34a expression in senescent HDFs and increased miR-20a expression in young HDFs and increased miR-449a expression in both young and senescent HDFs. Our results also demonstrated that ectopic expression of miR-34a reduced the expression of CDK4 significantly (P<0.05. TRF inhibited miR-34a expression thus relieved its inhibition on CDK4 gene expression. No significant change was observed on the expression of CCND1, SIRT1, and miR-34a upstream transcriptional regulator, TP53. In conclusion tocotrienol-rich fraction prevented cellular senescence of human diploid fibroblasts via modulation of SA-miRNAs and target genes expression.

  13. Shifting p53-induced senescence to cell death by TIS21(/BTG2/Pc3) gene through posttranslational modification of p53 protein.

    Science.gov (United States)

    Choi, Ok Ran; Ryu, Min Sook; Lim, In Kyoung

    2016-09-01

    Cellular senescence and apoptosis can be regulated by p53 activity, although the underlying mechanism of the switch between the two events remains largely unknown. Cells exposed to cancer chemotherapy can escape to senescence phenotype rather than undergoing apoptosis. By employing adenoviral transduction of p53 or TIS21 genes, we observed shifting of p53 induced-senescence to apoptosis in EJ bladder cancer cells, which express H-RasV12 and mutant p53; transduction of p53 increased H-RasV12 expression along with senescence phenotypes, whereas coexpression with TIS21 (p53+TIS21) induced cell death rather than senescence. The TIS21-mediated switch of senescence to apoptosis was accompanied by nuclear translocation of p53 protein and its modifications on Ser-15 and Ser-46 phosphorylation and acetylations on Lys-120, -320, -373 and -382 residues. Mechanistically, TIS21(/BTG2) regulated posttranslational modification of p53 via enhancing miR34a and Bax expressions as opposed to inhibiting SIRT1 and Bcl2 expression. At the same time, TIS21 increased APAF-1 and p53AIP1 expressions, but inhibited the interaction of p53 with iASPP. In vitro tumorigenicity was significantly reduced in the p53+TIS21 expresser through inhibiting micro-colony proliferation by TIS21. Effect of TIS21 on the regulation of p53 activity was confirmed by knockdown of TIS21 expression by RNA interference. Therefore, we suggest TIS21 expression as an endogenous cell death inducer at the downstream of p53 gene, which might be useful for intractable cancer chemotherapy.

  14. Feline chronic kidney disease is associated with shortened telomeres and increased cellular senescence.

    Science.gov (United States)

    Quimby, Jessica M; Maranon, David G; Battaglia, Christine L R; McLeland, Shannon M; Brock, William T; Bailey, Susan M

    2013-08-01

    Telomeres are protective structures at the ends of chromosomes that have important implications for aging. To address the question of whether telomeres contribute to feline chronic kidney disease (CKD), we evaluated kidney, liver, and skin samples from 12 cats with naturally occurring CKD, 12 young normal cats, and 6 old normal cats. Telomere length was assessed using standard telomere fluorescent in situ hybridization (TEL-FISH) combined with immunohistochemistry (TELI-FISH) to identify proximal (PTEC) and distal tubular epithelial cells (DTEC), whereas senescence-associated β-galactosidase (SABG) staining was used to evaluate senescence. Results revealed statistically significant decreases in the average telomere fluorescence intensity (TFI) of PTEC in CKD cats compared with young and geriatric normal cats, and in the DTEC of CKD cats compared with young normal cats. When histograms of individual TFI were compared, statistically significant decreases in the PTEC and DTEC of CKD cats were observed compared with young and geriatric normal cats. Concomitantly, a statistically significant increase in SABG staining was seen in CKD kidney samples compared with young normal cats. CKD cats tended to have increased SABG staining in the kidney compared with normal geriatric cats, but this did not reach statistical significance. No significant telomere shortening in liver or skin from any group was observed. Real-time quantitative telomeric repeat amplification protocol assessment of renal telomerase activity revealed comparable low levels of telomerase activity in all groups. Our results suggest that shortened telomeres and increased senescence in the kidneys of CKD cats may represent novel targets for interventional therapy.

  15. Jasmonates during senescence

    Science.gov (United States)

    Seltmann, Martin A; Hussels, Wiebke

    2010-01-01

    Jasmonic acid and derivatives are oxylipin signaling compounds derived from linolenic acid. Jasmonates accumulate during natural and dark-induced senescence but the increase in these compounds is not essential for the initiation or progression of these senescence processes. Here we report that during natural and dark-induced senescence the increase in jasmonate levels does not trigger jasmonate signaling. Furthermore we provide evidence that jasmonate production might result from membrane turnover during dark-induced senescence. PMID:21057217

  16. Senescence-Induced Alterations of Laminin Chain Expression Modulate Tumorigenicity of Prostate Cancer Cells

    Directory of Open Access Journals (Sweden)

    Cynthia C.T. Sprenger

    2008-12-01

    Full Text Available Prostate cancer is an age-associated epithelial cancer, and as such, it contributes significantly to the mortality of the elderly. Senescence is one possible mechanism by which the body defends itself against various epithelial cancers. Senescent cells alter the microenvironment, in part, through changes to the extracellular matrix. Laminins (LMs are extracellular proteins important to both the structure and function of the microenvironment. Overexpression of the senescence-associated gene mac25 in human prostate cancer cells resulted in increased mRNA levels of the LM α4 and β2 chains compared to empty vector control cells. The purpose of this study was to examine the effects of these senescence-induced LM chains on tumorigenicity of prostate cancer cells. We created stable M12 human prostate cancer lines overexpressing either the LM α4 or β2 chain or both chains. Increased expression of either the LM α4 or β2 chain resulted in increased in vitro migration and in vivo tumorigenicity of those cells, whereas high expression of both chains led to decreased in vitro proliferation and in vivo tumorigenicity compared to M12 control cells. This study demonstrates that senescent prostate epithelial cells can alter the microenvironment and that these changes modulate progression of prostate cancer.

  17. The p53-reactivating small molecule RITA induces senescence in head and neck cancer cells.

    Directory of Open Access Journals (Sweden)

    Hui-Ching Chuang

    Full Text Available TP53 is the most commonly mutated gene in head and neck cancer (HNSCC, with mutations being associated with resistance to conventional therapy. Restoring normal p53 function has previously been investigated via the use of RITA (reactivation of p53 and induction of tumor cell apoptosis, a small molecule that induces a conformational change in p53, leading to activation of its downstream targets. In the current study we found that RITA indeed exerts significant effects in HNSCC cells. However, in this model, we found that a significant outcome of RITA treatment was accelerated senescence. RITA-induced senescence in a variety of p53 backgrounds, including p53 null cells. Also, inhibition of p53 expression did not appear to significantly inhibit RITA-induced senescence. Thus, this phenomenon appears to be partially p53-independent. Additionally, RITA-induced senescence appears to be partially mediated by activation of the DNA damage response and SIRT1 (Silent information regulator T1 inhibition, with a synergistic effect seen by combining either ionizing radiation or SIRT1 inhibition with RITA treatment. These data point toward a novel mechanism of RITA function as well as hint to its possible therapeutic benefit in HNSCC.

  18. Changes in autophagy, proteasome activity and metabolism to determine a specific signature for acute and chronic senescent mesenchymal stromal cells.

    Science.gov (United States)

    Capasso, Stefania; Alessio, Nicola; Squillaro, Tiziana; Di Bernardo, Giovanni; Melone, Mariarosa A; Cipollaro, Marilena; Peluso, Gianfranco; Galderisi, Umberto

    2015-11-24

    A sharp definition of what a senescent cell is still lacking since we do not have in depth understanding of mechanisms that induce cellular senescence. In addition, senescent cells are heterogeneous, in that not all of them express the same genes and present the same phenotype. To further clarify the classification of senescent cells, hints may be derived by the study of cellular metabolism, autophagy and proteasome activity. In this scenario, we decided to study these biological features in senescence of Mesenchymal Stromal Cells (MSC). These cells contain a subpopulation of stem cells that are able to differentiate in mesodermal derivatives (adipocytes, chondrocytes, osteocytes). In addition, they can also contribute to the homeostatic maintenance of many organs, hence, their senescence could be very deleterious for human body functions. We induced MSC senescence by oxidative stress, doxorubicin treatment, X-ray irradiation and replicative exhaustion. The first three are considered inducers of acute senescence while extensive proliferation triggers replicative senescence also named as chronic senescence. In all conditions, but replicative and high IR dose senescence, we detected a reduction of the autophagic flux, while proteasome activity was impaired in peroxide-treated and irradiated cells. Differences were observed also in metabolic status. In general, all senescent cells evidenced metabolic inflexibility and prefer to use glucose as energy fuel. Irradiated cells with low dose of X-ray and replicative senescent cells show a residual capacity to use fatty acids and glutamine as alternative fuels, respectively. Our study may be useful to discriminate among different senescent phenotypes.

  19. Identification and Characterization of a Potent Activator of p53-Independent Cellular Senescence via a Small-Molecule Screen for Modifiers of the Integrated Stress Response

    Science.gov (United States)

    Sayers, Carly M.; Papandreou, Ioanna; Guttmann, David M.; Maas, Nancy L.; Diehl, J. Alan; Witze, Eric S.; Koong, Albert C.

    2013-01-01

    The Integrated Stress Response (ISR) is a signaling program that enables cellular adaptation to stressful conditions like hypoxia and nutrient deprivation in the tumor microenvironment. An important effector of the ISR is activating transcription factor 4 (ATF4), a transcription factor that regulates genes involved in redox homeostasis and amino acid metabolism and transport. Because both inhibition and overactivation of the ISR can induce tumor cell death, modulators of ATF4 expression could prove to be clinically useful. In this study, chemical libraries were screened for modulators of ATF4 expression. We identified one compound, E235 (N-(1-benzyl-piperidin-4-yl)-2-(4-fluoro-phenyl)-benzo[d]imidazo[2,1-b]thiazole-7-carboxamide), that activated the ISR and dose-dependently increased levels of ATF4 in transformed cells. A dose-dependent decrease in viability was observed in several mouse and human tumor cell lines, and knockdown of ATF4 significantly increased the antiproliferative effects of E235. Interestingly, low μM doses of E235 induced senescence in many cell types, including HT1080 human fibrosarcoma and B16F10 mouse melanoma cells. E235-mediated induction of senescence was not dependent on p21 or p53; however, p21 conferred protection against the growth inhibitory effects of E235. Treatment with E235 resulted in an increase in cells arrested at the G2/M phase with a concurrent decrease in S-phase cells. E235 also activated DNA damage response signaling, resulting in increased levels of Ser15-phosphorylated p53, γ-H2AX, and phosphorylated checkpoint kinase 2 (Chk2), although E235 does not appear to cause physical DNA damage. Induction of γ-H2AX was abrogated in ATF4 knockdown cells. Together, these results suggest that modulation of the ISR pathway with the small molecule E235 could be a promising antitumor strategy. PMID:23229510

  20. Inhibition of the phosphoinositide 3-kinase pathway induces a senescence-like arrest mediated by p27Kip1

    NARCIS (Netherlands)

    Collado, M.; Medema, R.H.; Garcia-Cao, I.; Dubuisson, M.L.N.; Barradas, M.; Glassford, J.; Rivas, C.; Burgering, B.M.T.; Serrano, M.; Lam, E.W.-F.

    2000-01-01

    A senescence-like growth arrest is induced in mouse primary embryo fibroblasts by inhibitors of phosphoinositide 3-kinase (PI3K). We observed that senescence-like growth arrest is correlated with an increase in p27Kip1 but that down-regulation of other cyclin-dependent kinase (CDK) inhibitors, inclu

  1. The Identification of Senescence-Specific Genes during the Induction of Senescence in Prostate Cancer Cells

    Directory of Open Access Journals (Sweden)

    Steven R. Schwarze

    2005-09-01

    Full Text Available Classic mechanisms of tumor response to chemotherapy include apoptosis, mitotic catastrophe. Recent studies have suggested that cellular senescence, a terminal proliferation arrest seen in vitro, may be invoked during the exposure of cancer cells to chemotherapeutic agents. To identify markers associated specifically with the cellular senescence phenotype, we utilized expression data from cDNA microarray experiments identifying transcripts whose expression levels increased as human prostate epithelial cells progressed to senescence. When screened against other growth-inhibitory conditions, including quiescence, apoptosis, many of these transcripts were also upregulated, indicating that similar pathways occur between apoptosis, senescence. A senescent-like phenotype was then induced in several prostate cancer cell lines using 5-aza-2′-deoxycytidine, doxorubicin, or Docetaxel. Treatment with these agents resulted in a significant increase in the induction of senescence-specific genes when compared to nonsenescent conditions. The performance of the panel was improved with fluorescence-activated cell sorting using PKH26 to isolate nonproliferating, viable, drug-treated populations, indicating that a heterogeneous response occurs with chemotherapy. We have defined an RNA-based gene panel that characterizes the senescent phenotype induced in cancer cells by drug treatment. These data also indicate that a panel of genes, rather than one marker, needs to be utilized to identify senescence.

  2. LDH inhibition impacts on heat shock response and induces senescence of hepatocellular carcinoma cells.

    Science.gov (United States)

    Manerba, Marcella; Di Ianni, Lorenza; Govoni, Marzia; Roberti, Marinella; Recanatini, Maurizio; Di Stefano, Giuseppina

    2017-07-15

    In normal cells, heat shock response (HSR) is rapidly induced in response to a variety of harmful conditions and represents one of the most efficient defense mechanism. In cancer tissues, constitutive activation converts HSR into a life-threatening process, which plays a major role in helping cell survival and proliferation. Overexpression of heat shock proteins (HSPs) has been widely reported in human cancers and was found to correlate with tumor progression. Hepatocellular carcinoma is one of the conditions in which HSR activation was shown to have the highest clinical significance. Transcription of HSPs is induced by HSF-1, which also activates glycolytic metabolism and increases the expression of LDH-A, the master regulator of the Warburg effect. In this paper, we tried to explore the relationship between HSR and LDH-A. In cultured hepatocellular carcinoma cells, by using two enzyme inhibitors (oxamate and galloflavin), we found that the reduction of LDH-A activity led to decreased level and function of the major HSPs involved in tumorigenesis. Galloflavin (a polyphenol) also inhibited the ATPase activity of two of the examined HSPs. Finally, hindering HSR markedly lowered the alpha-fetoprotein cellular levels and induced senescence. Specific inhibitors of single HSPs are currently under evaluation in different neoplastic diseases. However, one of the effects usually observed during treatment is a compensatory elevation of other HSPs, which decreases treatment efficacy. Our results highlight a connection between LDH and HSR and suggest LDH inhibition as a way to globally impact on this tumor promoting process. Copyright © 2017 Elsevier B.V. All rights reserved.

  3. Suppressor of Overexpression of CO 1 Negatively Regulates Dark-Induced Leaf Degreening and Senescence by Directly Repressing Pheophytinase and Other Senescence-Associated Genes in Arabidopsis.

    Science.gov (United States)

    Chen, Junyi; Zhu, Xiaoyu; Ren, Jun; Qiu, Kai; Li, Zhongpeng; Xie, Zuokun; Gao, Jiong; Zhou, Xin; Kuai, Benke

    2017-03-01

    Although the biochemical pathway of chlorophyll (Chl) degradation has been largely elucidated, how Chl is rapidly yet coordinately degraded during leaf senescence remains elusive. Pheophytinase (PPH) is the enzyme for catalyzing the removal of the phytol group from pheophytin a, and PPH expression is significantly induced during leaf senescence. To elucidate the transcriptional regulation of PPH, we used a yeast (Saccharomyces cerevisiae) one-hybrid system to screen for its trans-regulators. SUPPRESSOR OF OVEREXPRESSION OF CO 1 (SOC1), a key flowering pathway integrator, was initially identified as one of the putative trans-regulators of PPH After dark treatment, leaves of an SOC1 knockdown mutant (soc1-6) showed an accelerated yellowing phenotype, whereas those of SOC1-overexpressing lines exhibited a partial stay-green phenotype. SOC1 and PPH expression showed a negative correlation during leaf senescence. Substantially, SOC1 protein could bind specifically to the CArG box of the PPH promoter in vitro and in vivo, and overexpression of SOC1 significantly inhibited the transcriptional activity of the PPH promoter in Arabidopsis (Arabidopsis thaliana) protoplasts. Importantly, soc1-6 pph-1 (a PPH knockout mutant) double mutant displayed a stay-green phenotype similar to that of pph-1 during dark treatment. These results demonstrated that SOC1 inhibits Chl degradation via negatively regulating PPH expression. In addition, measurement of the Chl content and the maximum photochemical efficiency of photosystem II of soc1-6 and SOC1-OE leaves after dark treatment suggested that SOC1 also negatively regulates the general senescence process. Seven SENESCENCE-ASSOCIATED GENES (SAGs) were thereafter identified as its potential target genes, and NONYELLOWING1 and SAG113 were experimentally confirmed. Together, we reveal that SOC1 represses dark-induced leaf Chl degradation and senescence in general in Arabidopsis.

  4. Quantitative Trait Loci Mapping of Dark-Induced Senescence in Winter Wheat (Triticum aestivum)

    Institute of Scientific and Technical Information of China (English)

    Hongwei Li; Fanyun Lin; Gui Wang; Ruilian Jing; Qi Zheng; Bin Li; Zhensheng Li

    2012-01-01

    In order to explore the genetics of dark-induced senescence in winter wheat (Triticum aestivum L.),aquantitative trait loci (QTL) analysis was carried out in a doubled haploid population developed from across between the varieties Hanxuan 10 (HX) and Lumai 14 (LM).The senescence parameters chlorophyll content (Chl a+b,Chl a,and Chl b),original fluorescence (Fo),maximum fluorescence level (Fm),maximum photochemical efficiency (Fv/Fm),and ratio of variable fluorescence to original fluorescence (Fv/Fo) were evaluated in the second leaf of whole three-leaf seedlings subjected to 7 d of darkness.A total of 43 QTLs were identified that were associated with dark-induced senescence using composite interval mapping.These QTLs were mapped to 20 loci distributed on 11 chromosomes:1B,1D,2A,2B,3B,3D,5D,6A,6B,7A,and 7B.The phenotypic variation explained by each QTL ranged from 7.5% to 19.4%.Eleven loci coincided with two or more of the analyzed parameters.In addition,14 loci co-located or were linked with previously reported QTLs regulating flag leaf senescence,tolerance to high light stress,and grain protein content (Gpc),separately.

  5. Resveratrol-induced augmentation of telomerase activity delays senescence of endothelial progenitor cells

    Institute of Scientific and Technical Information of China (English)

    WANG Xiao-bin; ZHU Li; HUANG Jun; YIN Yi-gang; KONG Xiang-qing; RONG Qi-fei; SHI Ai-wu; CAO Ke-jiang

    2011-01-01

    Background Previous studies have shown that resveratrol increases endothelial progenitor cell (EPC) numbers and functional activity.Increased EPC numbers and activity are associated with the inhibition of EPC senescence.In this study,we investigated the effect of resveratrol on the senescence of EPCs,leading to potentiation of cellular function.Methods EPCs were isolated from human peripheral blood and identified immunocytochemically.EPCs were incubated with resveratrol (1,10,and 50 μmol/L) or control for specified times.After in vitro cultivation,acidic β-galactosidase staining revealed the extent of senescence in the cells.To gain further insight into the underlying mechanism of the effect of resveratrol,we measured telomerase activity using a polymerase chain reaction (PCR)-enzyme-linked immunosorbent assay (ELISA) technique.Furthermore,we measured the expression of human telomerase reverse transcriptase (hTERT) and the phosphorylation of Akt by immunoblotting.Results Resveratrol dose-dependently inhibited the onset of EPC senescence in culture.Resveratrol also significantly increased telomerase activity.Interestingly,quantitative real-time PCR analysis demonstrated that resveratrol dose-dependently increased the expression of the catalytic subunit,hTERT,an effect that was significantly inhibited by pharmacological phosphatidylinositol 3-kinase (PI3-K) blockers (wortmannin).The expression of hTERT is regulated by the PI3-K/Akt pathway; therefore,we examined the effect of resveratrol on Akt activity in EPCs.Immunoblotting analysis revealed that resveratrol led to dose-dependent phosphorylation and activation of Akt in EPCs.Conclusion Resveratrol delayed EPCs senescence in vitro,which may be dependent on telomerase activation.

  6. Nuclear accumulation of Yes-Associated Protein (YAP) maintains the survival of doxorubicin-induced senescent cells by promoting survivin expression.

    Science.gov (United States)

    Ma, Kai; Xu, Qing; Wang, Shuren; Zhang, Weina; Liu, Mei; Liang, Shufang; Zhu, Hongxia; Xu, Ningzhi

    2016-05-28

    Although chemotherapeutic drugs can induce senescence to prohibit further division of tumor cells, senescence could also promote tumorigenesis mainly through a senescence-associated secretory phenotype. Therefore, senescent tumor cells should be eliminated immediately to prevent drug resistance and recurrence. Here, we used a doxorubicin-induced senescence model to explore the mechanism underlying the survival of therapy-induced senescent cells. After low-dose doxorubicin treatment, tumor cells turned on a senescence program and became large and flattened, increasing their contact area with the extracellular matrix (ECM). Furthermore, Yes-associated protein (YAP) accumulated in the nucleus and YAP activity was increased in doxorubicin-induced senescent cells. Knockdown of YAP increased the sensitivity of cells to low-dose doxorubicin treatment, causing apoptosis rather than senescence. Moreover, the anti-apoptotic gene survivin, a YAP target gene, was overexpressed in senescent cells. Inhibition of survivin could lead to selective elimination of senescent cells through apoptosis. Our study indicates that nuclear accumulation of YAP could promote the survival of senescent cells by increasing survivin expression. Therefore, targeting YAP or survivin might be a new strategy for clearing senescent cancer cells during drug treatment.

  7. Pseudolaric acid B induces apoptosis, senescence, and mitotic arrest in human breast cancer MCF-7

    Institute of Scientific and Technical Information of China (English)

    Jing-hua YU; Qiao CUI; Yuan-yuan JIANG; Wei YANG; Shin-ichi TASHIRO; Satoshi ONODERA; Takashi IKEJIMA

    2007-01-01

    Aim: The aim of the present study was to investigate the inhibitory effect of pseudolaric acid B (PAB) on human breast cancer MCF-7 cells. Methods: 3-(4,5- dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide analysis, morphological changes, acridine orange staining, and agarose gel electrophoresis were applied to detect apoptosis. The percentage of apoptotic and necrotic cells was calcu- lated by the lactate dehydrogenase activity-based cytotoxicity assay; senescence associated (SA)-β-galactosidase activity was detected to evaluate senescence; flow cytometric analysis of propidium iodide staining was carried out to investi- gate the distribution of cell cycle, and the protein expression was examined by Western blot analysis. Results: During apoptosis, the half maximal inhibitory concentration IC502 was 3.4 and 1.35 μmol/L at 36 and 48 h after PAB treatment, respectively. The MCF-7 cells exposed to PAB showed typical characteristics of apoptosis, including the morphological changes and DNA fragmentation. The MCF-7 cells treated with 4 μmol/L PAB for 36 h underwent apoptosis, but not necrosis. The apoptosis induced by PAB was independent of the death receptor pathway. The senescent cells became larger and flatter, and the SA-β-galactosi- dase staining was positive. PAB induced obvious mitotic arrest and it preceded apoptosis and senescence. The expressions of p21 and p53 was upregulated with PAB treatment, and cyclin B 1 was upregulated and transported from the cyto- plasm to nuclei, and sustained stable levels. Conclusion: PAB induced mitotic arrest in the MCF-7 cells and inhibited proliferation through apoptosis and senescence. The apoptosis was independent of the death receptor pathway.

  8. Photobiomodulation on senescence

    Science.gov (United States)

    Liu, Timon Cheng-Yi; Cheng, Lei; Rong, Dong-Liang; Xu, Xiao-Yang; Cui, Li-Ping; Lu, Jian; Deng, Xiao-Yuan; Liu, Song-Hao

    2006-09-01

    Photobiomodulation (PBM) is an effect oflow intensity monochromatic light or laser irradiation (LIL) on biological systems. which stimulates or inhibits biological functions but does not result in irreducible damage. It has been observed that PBM can suppress cellular senescence, reverse skin photoageing and improve fibromyalgia. In this paper, the biological information model of photobiomodulation (BIMP) is used to discuss its mechanism. Cellular senescence can result from short, dysfunctional telomeres, oxidative stress, or oncogene expression, and may contribute to aging so that it can be seen as a decline of cellular function in which cAMP plays an important role, which provide a foundation for PBM on senescence since cellular senescence is a reasonable model of senescence and PBM is a cellular rehabilitation in which cAMP also plays an important role according to BIMP. The PBM in reversing skin photoageing and improving fibromyalgia are then discussed in detail.

  9. Protein oxidation and aggregation in UVA-irradiated Escherichia coli cells as signs of accelerated cellular senescence.

    Science.gov (United States)

    Bosshard, Franziska; Riedel, Kathrin; Schneider, Thomas; Geiser, Carina; Bucheli, Margarete; Egli, Thomas

    2010-11-01

    Solar disinfection (SODIS) is a simple drinking water treatment method that improves microbiological water quality where other means are unavailable. It makes use of the deleterious effect of solar irradiation on pathogenic microbes and viruses. A positive impact on health has been documented in several epidemiological studies. However, the molecular mechanisms damaging cells during this simple treatment are not yet fully understood. Here we show that protein damage is crucial in the process of inactivation by sunlight. Protein damages in UVA-irradiated Escherichia coli cells have been evaluated by an immunoblot method for carbonylated proteins and an aggregation assay based on semi-quantitative proteomics. A wide spectrum of structural and enzymatic proteins within the cell is affected by carbonylation and aggregation. Vital cellular functions like the transcription and translation apparatus, transport systems, amino acid synthesis and degradation, respiration, ATP synthesis, glycolysis, the TCA cycle, chaperone functions and catalase are targeted by UVA irradiation. The protein damage pattern caused by SODIS strongly resembles the pattern caused by reactive oxygen stress. Hence, sunlight probably accelerates cellular senescence and leads to the inactivation and finally death of UVA-irradiated cells.

  10. 细胞衰老与肿瘤发生%Cellular senescence and carcinogenesis

    Institute of Scientific and Technical Information of China (English)

    胡兵; 安红梅; 沈克平

    2008-01-01

    细胞衰老(cell senescence)是指细胞在信号转导作用下不可逆地脱离细胞周期并丧失增殖能力后进入的一种相对稳定的状态.细胞衰老有增殖衰老与早熟衰老两种形式:增殖衰老由端粒缩短激发的信号转导激发,与TP53/CDKNla(p21WAF-1/cip1)/pRB/E2F信号通路密切相关;早熟衰老由细胞内在或外在急慢性应激信号引发,与TP53/CDKN1a(p21WAF-1/Cip1)/pRB/E2F或CDKN2a(p16ink4A)/pRB/E2F信号通路相关.日前研究已经证实早熟衰老是细胞在癌变过程中的天然屏障,是继DNA修复、细胞凋亡后的第三大细胞内在抗癌机制,在机体防止肿瘤形成中起重要作用.

  11. Oxidative stress and leaf senescence

    Directory of Open Access Journals (Sweden)

    Sedigheh Hatami

    2011-11-01

    Full Text Available Abstract Background Senescence is an important developmental process that leads to the cell death through highly regulated genetically controlled processes in plants. Biotic and abiotic Oxidative stresses can also artificially induce senescence and increase the production of reactive oxygen species (ROS specifically in chloroplast. One of the important oxidative stresses is paraquat that induces deviation of electron from photosynthesis electron chain and lead to the production of more ROS in chloroplast. Plants have evolved special adoptive mechanism to reallocate nutrient to reproductive and juvenile organs in senescence and different oxidative stresses. Rubisco seems to be the most abundant protein in plants and is involved in many changes during senescence. Results In the present study, the effects of ROS on Rubisco during senescence and oxidative stresses were evaluated by measuring photosynthesis factors such as net photosynthesis rate (Pn, stomatal conductance (G, evaporation rate (E, intra cellular CO2 concentration (Ci, fluorescence and total protein during three stages of development. Our results showed that in paraquat treated plants, CO2 assimilation is the most effective factor that refers to Rubisco damages. The highest correlation and regression coefficient belonged to Ci, while correlation coefficient between photosynthesis rate and total protein was much smaller. Conclusion It appears in the early stage of oxidative stresses such as exposing to paraquat, ROS has the most effect on Rubisco activity that induces more susceptibility to Rubisco specific protease. Moreover, Rubisco deactivation acts as an initiative signal for Rubisco degradation.

  12. Salidroside protects against premature senescence induced by ultraviolet B irradiation in human dermal fibroblasts.

    Science.gov (United States)

    Mao, G-X; Xing, W-M; Wen, X-L; Jia, B-B; Yang, Z-X; Wang, Y-Z; Jin, X-Q; Wang, G-F; Yan, J

    2015-06-01

    Salidroside, the predominant component of a Chinese herbal medicine, Rhodiola rosea L., becomes an attractive bio-agent due to its multifunction. Although it is well proposed that this herbal medicine may have photoprotective effect according to the folk hearsay, the direct supportive experimental evidences linking the drug with skin ageing have rarely been reported so far. The study was conducted to investigate the photoprotective role of salidrosdie and its related mechanisms in vitro. First, a premature senescence model induced by UVB irradiation (250 mJ cm(-2)) in human dermal fibroblasts (HDFs) was established, and senescent phenotypes were evaluated by cell morphology, cell proliferation, senescence-associated beta-galactosidase (SA-β-gal) activity and cell cycle distribution. Then the photoprotective effect of salidroside was investigated. Cells were pre-treated with various doses of salidroside (1, 5 and 10 μM) followed by the sublethal dosage of UVB exposure and then were harvested for various detections, including senescence-associated phenotypes and molecules, alteration of oxidative stress, matrix metalloproteinase-1 (MMP-1) secretion and inflammatory response. Pre-treatment of salidroside dose dependently reversed the senescent state of HDFs induced by UVB as evidenced by elevated cell viability, decreased SA-β-gal activity and relieving of G1/G0 cell cycle arrest. UVB-induced increased protein expression of cyclin-dependent kinase (CDK) inhibitors p21(WAF) (1) and p16(INK) (4) was also repressed by salidrosdie treatment in a dose-dependent manner. Meanwhile, the increment of malondialdehyde (MDA) level in UVB-irradiated HDFs was inhibited upon salidroside treatment. Additionally, salidroside significantly attenuated UVB-induced synthesis of MMP-1 as well as the production of IL-6 and TNF-α in HDFs. Our data provided the evidences for the protective role of salidroside against UVB-induced premature senescence in HDFs probably via its anti

  13. Protease activated receptor-1 regulates macrophage-mediated cellular senescence : a risk for idiopathic pulmonary fibrosis

    NARCIS (Netherlands)

    Lin, Cong; Rezaee, Farhad; Waasdorp, Maaike; Shi, Kun; van der Poll, Tom; Borensztajn, Keren; Spek, C. Arnold

    2015-01-01

    Idiopathic pulmonary fibrosis (IPF) is a destructive disease in part resulting from premature or mature cellular aging. Protease-activated receptor-1 (PAR-1) recently emerged as a critical component in the context of fibrotic lung diseases. Therefore, we aimed to study the role of macrophages in PAR

  14. DNA-Damage-Induced Type I Interferon Promotes Senescence and Inhibits Stem Cell Function

    Directory of Open Access Journals (Sweden)

    Qiujing Yu

    2015-05-01

    Full Text Available Expression of type I interferons (IFNs can be induced by DNA-damaging agents, but the mechanisms and significance of this regulation are not completely understood. We found that the transcription factor IRF3, activated in an ATM-IKKα/β-dependent manner, stimulates cell-autonomous IFN-β expression in response to double-stranded DNA breaks. Cells and tissues with accumulating DNA damage produce endogenous IFN-β and stimulate IFN signaling in vitro and in vivo. In turn, IFN acts to amplify DNA-damage responses, activate the p53 pathway, promote senescence, and inhibit stem cell function in response to telomere shortening. Inactivation of the IFN pathway abrogates the development of diverse progeric phenotypes and extends the lifespan of Terc knockout mice. These data identify DNA-damage-response-induced IFN signaling as a critical mechanism that links accumulating DNA damage with senescence and premature aging.

  15. Activation of Bmp2-Smad1 signal and its regulation by coordinated alteration of H3K27 trimethylation in Ras-induced senescence.

    Directory of Open Access Journals (Sweden)

    Atsushi Kaneda

    2011-11-01

    Full Text Available Cellular senescence involves epigenetic alteration, e.g. loss of H3K27me3 in Ink4a-Arf locus. Using mouse embryonic fibroblast (MEF, we here analyzed transcription and epigenetic alteration during Ras-induced senescence on genome-wide scale by chromatin immunoprecipitation (ChIP-sequencing and microarray. Bmp2 was the most activated secreted factor with H3K4me3 gain and H3K27me3 loss, whereas H3K4me3 loss and de novo formation of H3K27me3 occurred inversely in repression of nine genes, including two BMP-SMAD inhibitors Smad6 and Noggin. DNA methylation alteration unlikely occurred. Ras-activated cells senesced with nuclear accumulation of phosphorylated SMAD1/5/8. Senescence was bypassed in Ras-activated cells when Bmp2/Smad1 signal was blocked by Bmp2 knockdown, Smad6 induction, or Noggin induction. Senescence was induced when recombinant BMP2 protein was added to Bmp2-knocked-down Ras-activated cells. Downstream Bmp2-Smad1 target genes were then analyzed genome-wide by ChIP-sequencing using anti-Smad1 antibody in MEF that was exposed to BMP2. Smad1 target sites were enriched nearby transcription start sites of genes, which significantly correlated to upregulation by BMP2 stimulation. While Smad6 was one of Smad1 target genes to be upregulated by BMP2 exposure, Smad6 repression in Ras-activated cells with increased enrichment of Ezh2 and gain of H3K27me3 suggested epigenetic disruption of negative feedback by Polycomb. Among Smad1 target genes that were upregulated in Ras-activated cells without increased repressive mark, Parvb was found to contribute to growth inhibition as Parvb knockdown lead to escape from senescence. It was revealed through genome-wide analyses in this study that Bmp2-Smad1 signal and its regulation by harmonized epigenomic alteration play an important role in Ras-induced senescence.

  16. Gardenia jasminoides extract-capped gold nanoparticles reverse hydrogen peroxide-induced premature senescence.

    Science.gov (United States)

    Chae, Seon Yeong; Park, Sun Young; Park, Jin Oh; Lee, Kyu Jin; Park, Geuntae

    2016-11-01

    This study reports a green approach for synthesis of gold nanoparticles using Gardenia jasminoides extract, and specifically, can potentially enhance anti senescence activity. Biological synthesis of gold nanoparticles is ecofriendly and effective for the development of environmentally sustainable nanoparticles compared with existing methods. Here, we developed a simple, fast, efficient, and ecofriendly approach to the synthesis of gold nanoparticles by means of a Gardenia jasminoides extract. These G. jasminoides extract-capped gold nanoparticles (GJ-GNPs) were characterized by UV-vis, high resolution transmission electron microscopy (HR-TEM), X-ray diffraction (XRD), and Furrier transform infrared spectroscopy (FT-IR). The synthesized GJ-GNPs turned red and showed maximal absorbance at 540nm. Thus, GJ-GNPs were synthesized successfully. We hypothesized that GJ-GNPs would protect ARPE19 cells from hydrogen peroxide-induced premature senescence. SA-β-gal activity was elevated in hydrogen peroxide-treated cells, however, this effect was attenuated by GJ-GNP treatment. Moreover, compared with the normal control, hydrogen peroxide treatment significantly increased lysosome content of the cells and production of reactive oxygen species (ROS). GJ-GNPs effectively attenuated the increase in lysosome content and ROS production in these senescent cells. According to cell cycle analysis, G2/M arrest was promoted by hydrogen peroxide treatment in ARPE19 cells, however, this change was reversed by GJ-GNPs. Western blot analysis showed that treatment with GJ-GNPs increased the expression of p53, p21, SIRT3, HO-1, and NQO1 in senescent cells. Our findings should advance the understanding of premature senescence and may lead to therapeutic use of GJ-GNPs in retina-related regenerative medicine.

  17. Hormonal changes during salinity-induced leaf senescence in tomato (Solanum lycopersicum L.)

    Science.gov (United States)

    Ghanem, Michel Edmond; Albacete, Alfonso; Martínez-Andújar, Cristina; Acosta, Manuel; Romero-Aranda, Remedios; Dodd, Ian C.; Lutts, Stanley; Pérez-Alfocea, Francisco

    2008-01-01

    Leaf senescence is one of the most limiting factors to plant productivity under salinity. Both the accumulation of specific toxic ions (e.g. Na+) and changes in leaf hormone relations are involved in the regulation of this process. Tomato plants (Solanum lycopersicum L. cv Moneymaker) were cultivated for 3 weeks under high salinity (100 mM NaCl) and leaf senescence-related parameters were studied during leaf development in relation to Na+ and K+ contents and changes in abscisic acid (ABA), cytokinins, the ethylene precursor 1-aminocyclopropane-1-carboxylic acid (ACC), and the auxin indole-3-acetic acid (IAA). Na+ accumulated to a similar extent in both leaves 4 and 5 (numbering from the base of the plant) and more quickly during the third week, while concurrently K+ contents sharply decreased. However, photosystem II efficiency, measured as the Fv/Fm ratio, decreased from the second week of salinization in leaf 4 but only at the end of the third week in the younger leaf 5. In the prematurely senescent leaf 4, ABA content increased linearly while IAA strongly decreased with salinization time. Although zeatin (Z) levels were scarcely affected by salinity, zeatin-riboside (ZR) and the total cytokinin content (Z+ZR) progressively decreased by 50% from the imposition of the stress. ACC was the only hormonal compound that increased in leaf tissue coincident with the onset of oxidative damage and the decline in chlorophyll fluorescence, and prior to massive Na+ accumulation. Indeed, (Z+ZR) and ACC contents and their ratio (Z+ZR/ACC) were the hormonal parameters best correlated with the onset and progression of leaf senescence. The influence of different hormonal changes on salt-induced leaf senescence is discussed. PMID:18573798

  18. Inhibition of Notch pathway arrests PTEN-deficient advanced prostate cancer by triggering p27-driven cellular senescence

    Science.gov (United States)

    Revandkar, Ajinkya; Perciato, Maria Luna; Toso, Alberto; Alajati, Abdullah; Chen, Jingjing; Gerber, Hermeto; Dimitrov, Mitko; Rinaldi, Andrea; Delaleu, Nicolas; Pasquini, Emiliano; D'Antuono, Rocco; Pinton, Sandra; Losa, Marco; Gnetti, Letizia; Arribas, Alberto; Fraering, Patrick; Bertoni, Francesco; Nepveu, Alain; Alimonti, Andrea

    2016-01-01

    Activation of NOTCH signalling is associated with advanced prostate cancer and treatment resistance in prostate cancer patients. However, the mechanism that drives NOTCH activation in prostate cancer remains still elusive. Moreover, preclinical evidence of the therapeutic efficacy of NOTCH inhibitors in prostate cancer is lacking. Here, we provide evidence that PTEN loss in prostate tumours upregulates the expression of ADAM17, thereby activating NOTCH signalling. Using prostate conditional inactivation of both Pten and Notch1 along with preclinical trials carried out in Pten-null prostate conditional mouse models, we demonstrate that Pten-deficient prostate tumours are addicted to the NOTCH signalling. Importantly, we find that pharmacological inhibition of γ-secretase promotes growth arrest in both Pten-null and Pten/Trp53-null prostate tumours by triggering cellular senescence. Altogether, our findings describe a novel pro-tumorigenic network that links PTEN loss to ADAM17 and NOTCH signalling, thus providing the rational for the use of γ-secretase inhibitors in advanced prostate cancer patients. PMID:27941799

  19. Cell-penetrating superoxide dismutase attenuates oxidative stress-induced senescence by regulating the p53-p21Cip1 pathway and restores osteoblastic differentiation in human dental pulp stem cells

    Directory of Open Access Journals (Sweden)

    Park YJ

    2012-09-01

    Full Text Available Yoon Jung Choi,1,* Jue Yeon Lee,2,* Chong Pyoung Chung,2 Yoon Jeong Park,1,21Craniomaxillofacial Reconstructive Sciences, Dental Research Institute, School of Dentistry, Seoul National University, Seoul, Republic of Korea; 2Research Institute, Nano Intelligent Biomedical Engineering, Seoul, Republic of Korea*These authors contributed equally to this workBackground: Human dental pulp stem cells (DPSCs have potential applications in tissue regeneration because of their convenient cell harvesting procedures and multipotent capacity. However, the tissue regenerative potential of DPSCs is known to be negatively regulated by aging in long-term culture and under oxidative stress. With an aim of reducing cellular senescence and oxidative stress in DPSCs, an intracellular delivery system for superoxide dismutase 1 (SOD1 was developed. We conjugated SOD1 with a cell-penetrating peptide known as low-molecular weight protamine (LMWP, and investigated the effect of LMWP-SOD1 conjugates on hydrogen peroxide-induced cellular senescence and osteoblastic differentiation.Results: LMWP-SOD1 significantly attenuated enlarged and flattened cell morphology and increased senescence-associated β-galactosidase activity. Under the same conditions, LMWP-SOD1 abolished activation of the cell cycle regulator proteins, p53 and p21Cip1, induced by hydrogen peroxide. In addition, LMWP-SOD1 reversed the inhibition of osteoblastic differentiation and downregulation of osteogenic gene markers induced by hydrogen peroxide. However, LMWP-SOD1 could not reverse the decrease in odontogenesis caused by hydrogen peroxide.Conclusion: Overall, cell-penetrating LMWP-SOD1 conjugates are effective for attenuation of cellular senescence and reversal of osteoblastic differentiation of DPSCs caused by oxidative stress inhibition. This result suggests potential application in the field of antiaging and tissue engineering to overcome the limitations of senescent stem cells.Keywords: superoxide

  20. Telomere shortening and cell senescence induced by perylene derivatives in A549 human lung cancer cells.

    Science.gov (United States)

    Taka, Thanachai; Huang, Liming; Wongnoppavich, Ariyaphong; Tam-Chang, Suk-Wah; Lee, T Randall; Tuntiwechapikul, Wirote

    2013-02-15

    Cancer cells evade replicative senescence by re-expressing telomerase, which maintains telomere length and hence chromosomal integrity. Telomerase inhibition would lead cancer cells to senesce and therefore prevent cancer cells from growing indefinitely. G-quadruplex ligands can attenuate telomerase activity by inducing G-quadruplex formation at the 3'-overhang of telomere and at the human telomerase reverse transcriptase (hTERT) promoter; the former prevents telomerase from accessing the telomere, and the latter acts as a transcriptional silencer. The present investigation found that perylene derivatives PM2 and PIPER induced G-quadruplex formation from both telomeric DNA and the hTERT promoter region in vitro. Further, TRAP assay showed that these compounds inhibited telomerase in a dose-dependent manner. When A549 human lung cancer cells were treated with these compounds, hTERT expression was down-regulated. Moreover, the crude protein extract from these treated cells exhibited less telomerase activity. In the long-term treatment of A549 lung cancer cells with sub-cytotoxic dose of these perylenes, telomere shortening, reduction of cell proliferation and tumorigenicity, and cell senescence were observed. The results of this study indicate that perylene derivatives warrant further consideration as effective agents for cancer therapy.

  1. Hepatoprotective Effects of Swimming Exercise against D-Galactose-Induced Senescence Rat Model

    Directory of Open Access Journals (Sweden)

    Chi-Chang Huang

    2013-01-01

    Full Text Available This study investigates whether a 12-week swimming exercise training can prevent liver damage or senescence associated biomarkers in an experimental aging model in rats. Twenty-three male Sprague-Dawley rats were divided into four groups: vehicle treatment with sedentary control (C, , aging induction with sedentary (A, , vehicle treatment with swimming exercise (SW, , and aging induction with swimming exercise (A + SW, . Rats in groups A and AS received intraperitoneal D-galactose injections (150 mg/kg/day for 12 weeks to induce aging. Rats in groups SW and A + SW were subjected to swimming exercise training for 12 weeks. Body weight, liver weight, epididymal fat mass, blood biochemistry, and liver pathology were performed at the end of the experiment. Hepatic senescence protein markers such as β-galactosidase, p53, and p21, as well as the inflammatory mediator, IL-6, were examined. The D-galactose-treated rats exhibited increases in AST and γ-GT plasma levels and β-galactosidase protein expression compared to the control group. Swimming exercise significantly reduced BW, epididymal fat mass, γ-GT activity, and p53, p21, and IL-6 protein levels compared to the aging group. These results suggest that a 12-week swimming exercise program suppresses senescence markers and downregulates inflammatory mediator in the liver tissues of D-galactose-induced aging rats.

  2. Histone deacetylase inhibitor valproic acid promotes the induction of pluripotency in mouse fibroblasts by suppressing reprogramming-induced senescence stress

    Energy Technology Data Exchange (ETDEWEB)

    Zhai, Yingying; Chen, Xi; Yu, Dehai [Stem Cell and Cancer Center, First Affiliated Hospital, Jilin University, Changchun, Jilin 130061 (China); Stanford University Medical School, Palo Alto Veterans Institute for Research, Palo Alto, CA 94304 (United States); Li, Tao [Stanford University Medical School, Palo Alto Veterans Institute for Research, Palo Alto, CA 94304 (United States); Cui, Jiuwei; Wang, Guanjun [Stem Cell and Cancer Center, First Affiliated Hospital, Jilin University, Changchun, Jilin 130061 (China); Hu, Ji-Fan, E-mail: jifan@stanford.edu [Stem Cell and Cancer Center, First Affiliated Hospital, Jilin University, Changchun, Jilin 130061 (China); Stanford University Medical School, Palo Alto Veterans Institute for Research, Palo Alto, CA 94304 (United States); Li, Wei, E-mail: jdyylw@163.com [Stem Cell and Cancer Center, First Affiliated Hospital, Jilin University, Changchun, Jilin 130061 (China)

    2015-09-10

    Histone deacetylase inhibitor valproic acid (VPA) has been used to increase the reprogramming efficiency of induced pluripotent stem cell (iPSC) from somatic cells, yet the specific molecular mechanisms underlying this effect is unknown. Here, we demonstrate that reprogramming with lentiviruses carrying the iPSC-inducing factors (Oct4-Sox2-Klf4-cMyc, OSKM) caused senescence in mouse fibroblasts, establishing a stress barrier for cell reprogramming. Administration of VPA protected cells from reprogramming-induced senescent stress. Using an in vitro pre-mature senescence model, we found that VPA treatment increased cell proliferation and inhibited apoptosis through the suppression of the p16/p21 pathway. In addition, VPA also inhibited the G2/M phase blockage derived from the senescence stress. These findings highlight the role of VPA in breaking the cell senescence barrier required for the induction of pluripotency. - Highlights: • Histone deacetylase inhibitor valproic acid enhances iPSC induction. • Valproic acid suppresses reprogramming-induced senescence stress. • Valproic acid downregulates the p16/p21 pathway in reprogramming. • This study demonstrates a new mechanistic role of valproic acid in enhancing reprogramming.

  3. Senescence Process in Primary Wilms' Tumor Cell Culture Induced by p53 Independent p21 Expression.

    Science.gov (United States)

    Theerakitthanakul, Korkiat; Khrueathong, Jeerasak; Kruatong, Jirasak; Graidist, Potchanapond; Raungrut, Pritsana; Kayasut, Kanita; Sangkhathat, Surasak

    2016-01-01

    Wilms tumor (WT) is an embryonal tumor occurring in developing kidney tissue. WT cells showing invasive cancer characteristics, also retain renal stem cell behaviours. In-vitro culture of WT is hampered by limited replicative potential. This study aimed to establish a longterm culture of WT cells to enable the study of molecular events to attempt to explain its cellular senescence. Primary cell cultures from fresh WT tumor specimen were established. Of 5 cultures tried, only 1 could be propagated for more than 7 passages. One culture, identified as PSU-SK-1, could be maintained > 35 passages and was then subjected to molecular characterization and evaluation for cancer characteristics. The cells consistently harbored concomitant mutations of CTNNB1 (Ser45Pro) and WT1 (Arg413Stop) thorough the cultivation. On Transwell invasion assays, the cells exhibited migration and invasion at 55% and 27% capability of the lung cancer cells, A549. On gelatin zymography, PSU-SK-1 showed high expression of the matrix metaloproteinase. The cells exhibited continuous proliferation with 24-hour doubling time until passages 28-30 when the growth slowed, showing increased cell size, retention of cells in G1/S proportion and positive β-galactosidase staining. As with those evidence of senescence in advanced cell passages, expression of p21 and cyclin D1 increased when the expression of β-catenin and its downstream protein, TCF, declined. There was also loss-of-expression of p53 in this cell line. In conclusion, cellular senescence was responsible for limited proliferation in the primary culture of WT, which was also associated with increased expression of p21 and was independent of p53 expression. Decreased activation of the Wnt signalling might explain the induction of p21 expression.

  4. Endopeptidase Isoenzyme Characteristics in Cucumis sativus Leaves During Dark-induced Senescence

    Institute of Scientific and Technical Information of China (English)

    Peng Zhang; Fei Wang; Lie-Feng Zhang; Qi Rui; Lang-Lai Xu

    2007-01-01

    The changes and characteristics of endopeptidase (EP) isoenzymes in cucumber (Cucumis sativus L.) leaves during dark-induced senescence were investigated by activity staining after gradient-polyacrylamide gel electrophoresis (G-PAGE) containing co-polymerized gelatin as substrate. The results showed that both the chlorophyll and the protein contents of leaves were decreased, and the protein degradation was correlated with the increase of proteolytic activity during the course of leaf senescence. Meanwhile, nine cucumber endopeptidases isoenzymes (CEP) with 140, 120, 106, 94, 76, 55, 46, 39 and 35 kDa molecular weights were detected. Four of these, CEP2, 3, 4 and CEP9 appeared all the time, but the changes of the activity were different during incubation. Another four CEPs (CEP5, 6, 7 and CEP8) whose activities increased with dark-induced time were only detected in senescent leaves.Furthermore, the biochemical properties of these nine CEP were also characterized. All the CEPs had high activities from 35 ℃ to 45 ℃, and the optimum temperature was found to be 40 ℃. However, the activities of CEPs were not detected below 25 ℃ or over 60 ℃. The activity bands appeared at a wide range of pH from 5.0 to 9.0, but the optimum pH was found at 7.0. No CEPs were detected at pH 4 or pH 10. By inhibition analysis we concluded that CEP2,3, 4 and CEP9 were serine endopeptidases and CEP6 was a kind of cysteine protease. It is suggested that serine endopeptidases might play a major role in cucumber leaf senescence, and for the first time, six senescencerelated endopeptidases (CEP1, 5, 6, 7, 8 and 9) were found in cucumber leaves.

  5. REDD1 protects osteoblast cells from gamma radiation-induced premature senescence.

    Directory of Open Access Journals (Sweden)

    Xiang Hong Li

    Full Text Available Radiotherapy is commonly used for cancer treatment. However, it often results in side effects due to radiation damage in normal tissue, such as bone marrow (BM failure. Adult hematopoietic stem and progenitor cells (HSPC reside in BM next to the endosteal bone surface, which is lined primarily by hematopoietic niche osteoblastic cells. Osteoblasts are relatively more radiation-resistant than HSPCs, but the mechanisms are not well understood. In the present study, we demonstrated that the stress response gene REDD1 (regulated in development and DNA damage responses 1 was highly expressed in human osteoblast cell line (hFOB cells after γ irradiation. Knockdown of REDD1 with siRNA resulted in a decrease in hFOB cell numbers, whereas transfection of PCMV6-AC-GFP-REDD1 plasmid DNA into hFOB cells inhibited mammalian target of rapamycin (mTOR and p21 expression and protected these cells from radiation-induced premature senescence (PS. The PS in irradiated hFOB cells were characterized by significant inhibition of clonogenicity, activation of senescence biomarker SA-β-gal, and the senescence-associated cytokine secretory phenotype (SASP after 4 or 8 Gy irradiation. Immunoprecipitation assays demonstrated that the stress response proteins p53 and nuclear factor κ B (NFkB interacted with REDD1 in hFOB cells. Knockdown of NFkB or p53 gene dramatically suppressed REDD1 protein expression in these cells, indicating that REDD1 was regulated by both factors. Our data demonstrated that REDD1 is a protective factor in radiation-induced osteoblast cell premature senescence.

  6. Cordyceps militaris Extract Protects Human Dermal Fibroblasts against Oxidative Stress-Induced Apoptosis and Premature Senescence

    Directory of Open Access Journals (Sweden)

    Jun Myoung Park

    2014-09-01

    Full Text Available Oxidative stress induced by reactive oxygen species (ROS is the major cause of degenerative disorders including aging and disease. In this study, we investigated whether Cordyceps militaris extract (CME has in vitro protective effects on hydrogen peroxide-induced oxidative stress in human dermal fibroblasts (HDFs. Our results showed that the 2,2-diphenyl-1-picrylhydrazyl (DPPH radical scavenging activity of CME was increased in a dose-dependent manner. We found that hydrogen peroxide treatment in HDFs increased ROS generation and cell death as compared with the control. However, CME improved the survival of HDFs against hydrogen peroxide-induced oxidative stress via inhibition of intracellular ROS production. CME treatment inhibited hydrogen peroxide-induced apoptotic cell death and apoptotic nuclear condensation in HDFs. In addition, CME prevented hydrogen peroxide-induced SA-β-gal-positive cells suggesting CME could inhibit oxidative stress-induced premature senescence. Therefore, these results suggest that CME might have protective effects against oxidative stress-induced premature senescence via scavenging ROS.

  7. Cordyceps militaris Extract Protects Human Dermal Fibroblasts against Oxidative Stress-Induced Apoptosis and Premature Senescence

    Science.gov (United States)

    Park, Jun Myoung; Lee, Jong Seok; Lee, Ki Rim; Ha, Suk-Jin; Hong, Eock Kee

    2014-01-01

    Oxidative stress induced by reactive oxygen species (ROS) is the major cause of degenerative disorders including aging and disease. In this study, we investigated whether Cordyceps militaris extract (CME) has in vitro protective effects on hydrogen peroxide-induced oxidative stress in human dermal fibroblasts (HDFs). Our results showed that the 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity of CME was increased in a dose-dependent manner. We found that hydrogen peroxide treatment in HDFs increased ROS generation and cell death as compared with the control. However, CME improved the survival of HDFs against hydrogen peroxide-induced oxidative stress via inhibition of intracellular ROS production. CME treatment inhibited hydrogen peroxide-induced apoptotic cell death and apoptotic nuclear condensation in HDFs. In addition, CME prevented hydrogen peroxide-induced SA-β-gal-positive cells suggesting CME could inhibit oxidative stress-induced premature senescence. Therefore, these results suggest that CME might have protective effects against oxidative stress-induced premature senescence via scavenging ROS. PMID:25230212

  8. PML, SUMOylation and senescence

    Directory of Open Access Journals (Sweden)

    Hugues eDe Thé

    2013-07-01

    Full Text Available Since its discovery, 25 years ago, PML has been an enigma. Implicated in the oncogenic PML/RARA fusion, forming elusive intranuclear domains, triggering cell death or senescence, controlled by and perhaps controlling SUMOylation... there are multiple PML-related issues. Here we review the reciprocal interactions between PML, senescence and SUMOylation, notably in the context of cellular transformation.

  9. Axitinib induces DNA damage response leading to senescence, mitotic catastrophe, and increased NK cell recognition in human renal carcinoma cells.

    Science.gov (United States)

    Morelli, Maria Beatrice; Amantini, Consuelo; Santoni, Matteo; Soriani, Alessandra; Nabissi, Massimo; Cardinali, Claudio; Santoni, Angela; Santoni, Giorgio

    2015-11-03

    Tyrosine kinase inhibitors (TKIs) including axitinib have been introduced in the treatment of renal cell carcinoma (RCC) because of their anti-angiogenic properties. However, no evidence are presently available on a direct cytotoxic anti-tumor activity of axitinib in RCC.Herein we reported by western blot analysis that axitinib treatment induces a DNA damage response (DDR) initially characterized by γ-H2AX phosphorylation and Chk1 kinase activation and at later time points by p21 overexpression in A-498 and Caki-2 RCC cells although with a different potency. Analysis by immunocytochemistry for the presence of 8-oxo-7,8-dihydro-2'-deoxyguanosine in cellular DNA and flow cytometry using the redox-sensitive fluorescent dye DCFDA, demonstrated that DDR response is accompanied by the presence of oxidative DNA damage and reactive oxygen species (ROS) generation. This response leads to G2/M cell cycle arrest and induces a senescent-like phenotype accompanied by enlargement of cells and increased senescence-associated β-galactosidase activity, which are abrogated by N-acetyl cysteine (NAC) pre-treatment. In addition, axitinib-treated cells undergo to cell death through mitotic catastrophe characterized by micronucleation and abnormal microtubule assembly as assessed by fluorescence microscopy.On the other hand, axitinib, through the DDR induction, is also able to increase the surface NKG2D ligand expression. Accordingly, drug treatment promotes NK cell recognition and degranulation in A-498 RCC cells in a ROS-dependent manner.Collectively, our results indicate that both cytotoxic and immunomodulatory effects on RCC cells can contribute to axitinib anti-tumor activity.

  10. Adiponectin induces CXCL1 secretion from cancer cells and promotes tumor angiogenesis by inducing stromal fibroblast senescence.

    Science.gov (United States)

    Cai, Lun; Xu, Shengyuan; Piao, Chunmei; Qiu, Shulan; Li, Huihua; Du, Jie

    2016-11-01

    Adiponectin is an adipocyte-specific adipocytokine with proliferative and pro-angiogenic effects that regulates many biological processes, including immunity, insulin resistance, and inflammation. The oncogenic role of adiponectin has been implicated in several cancer types. Stromal cells within tumor contribute tumor growth and angiogenesis; however, it is not clear that how adiponectin regulates stromal cell-mediated tumorigenesis. In this study, using the tumor xenograft models, we demonstrated that tumor development was severely impaired in mouse subcutaneous cancer tissue and metastasis tumor tissue in adiponectin knockout mice. Our results indicated adiponectin deficiency resulted in decrease of blood vessel and stromal senescent fibroblasts in subcutaneous and metastasis tumor tissue. These observations were confirmed in vitro, in which co-cultured tumor cells and fibroblasts treated with adiponectin promoted ECs tube formation. A secretion of CXCL1 by adiponectin-treated tumor cells was observed during the process of inducing stromal fibroblast senescence. Furthermore, stromal cells senescence was through p53 and p16 pathways. Taken together, our results indicate that adiponectin promotes stromal cell senescence within invasive colon cancer contributing to angiogenesis and tumor growth in part through the production of CXCL1 and may serve as a therapeutic target for tumor patients. © 2015 Wiley Periodicals, Inc. © 2015 Wiley Periodicals, Inc.

  11. The Arabidopsis transcription factor ABIG1 relays ABA signaled growth inhibition and drought induced senescence

    Science.gov (United States)

    Liu, Tie; Longhurst, Adam D; Talavera-Rauh, Franklin; Hokin, Samuel A; Barton, M Kathryn

    2016-01-01

    Drought inhibits plant growth and can also induce premature senescence. Here we identify a transcription factor, ABA INSENSITIVE GROWTH 1 (ABIG1) required for abscisic acid (ABA) mediated growth inhibition, but not for stomatal closure. ABIG1 mRNA levels are increased both in response to drought and in response to ABA treatment. When treated with ABA, abig1 mutants remain greener and produce more leaves than comparable wild-type plants. When challenged with drought, abig1 mutants have fewer yellow, senesced leaves than wild-type. Induction of ABIG1 transcription mimics ABA treatment and regulates a set of genes implicated in stress responses. We propose a model in which drought acts through ABA to increase ABIG1 transcription which in turn restricts new shoot growth and promotes leaf senescence. The results have implications for plant breeding: the existence of a mutant that is both ABA resistant and drought resistant points to new strategies for isolating drought resistant genetic varieties. DOI: http://dx.doi.org/10.7554/eLife.13768.001 PMID:27697148

  12. The emerging role of senescent cells in tissue homeostasis and pathophysiology

    Directory of Open Access Journals (Sweden)

    Kaoru Tominaga

    2015-05-01

    Full Text Available Cellular senescence is a state of permanent growth arrest and is thought to play a pivotal role in tumor suppression. Cellular senescence may play an important role in tumor suppression, wound healing, and protection against tissue fibrosis in physiological conditions in vivo. However, accumulating evidence that senescent cells may have harmful effects in vivo and may contribute to tissue remodeling, organismal aging, and many age-related diseases also exists. Cellular senescence can be induced by various intrinsic and extrinsic factors. Both p53/p21 and p16/RB pathways are important for irreversible growth arrest in senescent cells. Senescent cells secret numerous biologically active factors. This specific secretion phenotype by senescent cells may largely contribute to physiological and pathological consequences in organisms. Here I review the molecular basis of cell cycle arrest and the specific secretion phenotype in cellular senescence. I also summarize the current knowledge of the role of cellular senescence in vivo in physiological and pathological settings.

  13. Autocrine IL-6 mediates pituitary tumor senescence

    Science.gov (United States)

    Fuertes, Mariana; Ajler, Pablo; Carrizo, Guillermo; Cervio, Andrés; Sevlever, Gustavo; Stalla, Günter K.; Arzt, Eduardo

    2017-01-01

    Cellular senescence is a stable proliferative arrest state. Pituitary adenomas are frequent and mostly benign, but the mechanism for this remains unknown. IL-6 is involved in pituitary tumor progression and is produced by the tumoral cells. In a cell autonomous fashion, IL-6 participates in oncogene-induced senescence in transduced human melanocytes. Here we prove that autocrine IL-6 participates in pituitary tumor senescence. Endogenous IL-6 inhibition in somatotroph MtT/S shRNA stable clones results in decreased SA-β-gal activity and p16INK4a but increased pRb, proliferation and invasion. Nude mice injected with IL-6 silenced clones develop tumors contrary to MtT/S wild type that do not, demonstrating that clones that escape senescence are capable of becoming tumorigenic. When endogenous IL-6 is silenced, cell cultures derived from positive SA-β-gal human tumor samples decrease the expression of the senescence marker. Our results establish that IL-6 contributes to maintain senescence by its autocrine action, providing a natural model of IL-6 mediated benign adenoma senescence. PMID:27902467

  14. Sodium Chloride-Induced leaf senescence in Hydrocotyle bonariensis Lam. and Foeniculum vulgare L.

    Directory of Open Access Journals (Sweden)

    Claudia R. B. Haddad

    1999-01-01

    Full Text Available Leaf senescence induced by sodium chloride was studied in Hydrocotyle bonariensis Lam. and Foeniculum vulgare L. Both species belong to Umbelliferae family, however only H. bonariensis grows spontaneously in sandy soils of coastal regions (saline soils. Leaves of plants receiving nutrient solutions containing different concentrations of NaCl were evaluated for fresh and dry weights and chlorophyll content. The denaturating electrophoretic profiles of leaf proteins were also studied. Sodium chloride changed the protein profile of F. vulgare and hastened the leaf senescence of both the species. However, plants of H. bonariensis receiving 599 mM NaCl lasted longer than F. vulgare. Therefore, the occurrence of H. bonariensis in saline soils might be related with mechanisms of salinity tolerance.Foi estudada a senescência de folhas, induzida por cloreto de sódio, em Hidrocotyle bonariensis Lam. e Foeniculum vulgare L. Ambas as espécies pertencem à família Umbellifera. Contudo, somente H. bonariensis cresce espontaneamente em solos arenosos da região costeira (solos salinos. Foram verificadas a massa fresa, massa seca e concentração de clorofila de folhas de plantas recebendo soluções de NaCl com diferentes concentrações. O perfil eletroforético denaturante de proteínas das folhas também foi avaliado. Aplicação de cloreto de sódio levou a alterações no perfil protéico de F. vulgare e acelerou a senescência das folhas das duas espécies. Todavia, plantas de H. bonariensis recebendo soluções de NaCl com 599 mM sobreviveram mais tempo que as de F. vulgare. Assim a ocorrência de H. bonariensis em solos salinos pode estar relacionada a mecanismos de tolerância à salinidade.

  15. The role of nibrin in doxorubicin-induced apoptosis and cell senescence in Nijmegen Breakage Syndrome patients lymphocytes.

    Directory of Open Access Journals (Sweden)

    Olga Alster

    Full Text Available Nibrin plays an important role in the DNA damage response (DDR and DNA repair. DDR is a crucial signaling pathway in apoptosis and senescence. To verify whether truncated nibrin (p70, causing Nijmegen Breakage Syndrome (NBS, is involved in DDR and cell fate upon DNA damage, we used two (S4 and S3R spontaneously immortalized T cell lines from NBS patients, with the founding mutation and a control cell line (L5. S4 and S3R cells have the same level of p70 nibrin, however p70 from S4 cells was able to form more complexes with ATM and BRCA1. Doxorubicin-induced DDR followed by cell senescence could only be observed in L5 and S4 cells, but not in the S3R ones. Furthermore the S3R cells only underwent cell death, but not senescence after doxorubicin treatment. In contrary to doxorubicin treatment, cells from all three cell lines were able to activate the DDR pathway after being exposed to γ-radiation. Downregulation of nibrin in normal human vascular smooth muscle cells (VSMCs did not prevent the activation of DDR and induction of senescence. Our results indicate that a substantially reduced level of nibrin or its truncated p70 form is sufficient to induce DNA-damage dependent senescence in VSMCs and S4 cells, respectively. In doxorubicin-treated S3R cells DDR activation was severely impaired, thus preventing the induction of senescence.

  16. The essence of senescence

    National Research Council Canada - National Science Library

    Kuilman, Thomas; Michaloglou, Chrysiis; Mooi, Wolter J; Peeper, Daniel S

    2010-01-01

    Almost half a century after the first reports describing the limited replicative potential of primary cells in culture, there is now overwhelming evidence for the existence of "cellular senescence" in vivo...

  17. Silencing of the CaCP gene delays salt- and osmotic-induced leaf senescence in Capsicum annuum L.

    Science.gov (United States)

    Xiao, Huai-Juan; Yin, Yan-Xu; Chai, Wei-Guo; Gong, Zhen-Hui

    2014-05-12

    Cysteine proteinases have been known to participate in developmental processes and in response to stress in plants. Our present research reported that a novel CP gene, CaCP, was involved in leaf senescence in pepper (Capsicum annuum L.). The full-length CaCP cDNA is comprised of 1316 bp, contains 1044 nucleotides in open reading frame (ORF), and encodes a 347 amino acid protein. The deduced protein belongs to the papain-like cysteine proteases (CPs) superfamily, containing a highly conserved ERFNIN motif, a GCNGG motif and a conserved catalytic triad. This protein localized to the vacuole of plant cells. Real-time quantitative PCR analysis revealed that the expression level of CaCP gene was dramatically higher in leaves and flowers than that in roots, stems and fruits. Moreover, CaCP transcripts were induced upon during leaf senescence. CaCP expression was upregulated by plant hormones, especially salicylic acid. CaCP was also significantly induced by abiotic and biotic stress treatments, including high salinity, mannitol and Phytophthora capsici. Loss of function of CaCP using the virus-induced gene-silencing technique in pepper plants led to enhanced tolerance to salt- and osmotic-induced stress. Taken together, these results suggest that CaCP is a senescence-associated gene, which is involved in developmental senescence and regulates salt- and osmotic-induced leaf senescence in pepper.

  18. Silencing of the CaCP Gene Delays Salt- and Osmotic-Induced Leaf Senescence in Capsicum annuum L.

    Directory of Open Access Journals (Sweden)

    Huai-Juan Xiao

    2014-05-01

    Full Text Available Cysteine proteinases have been known to participate in developmental processes and in response to stress in plants. Our present research reported that a novel CP gene, CaCP, was involved in leaf senescence in pepper (Capsicum annuum L.. The full-length CaCP cDNA is comprised of 1316 bp, contains 1044 nucleotides in open reading frame (ORF, and encodes a 347 amino acid protein. The deduced protein belongs to the papain-like cysteine proteases (CPs superfamily, containing a highly conserved ERFNIN motif, a GCNGG motif and a conserved catalytic triad. This protein localized to the vacuole of plant cells. Real-time quantitative PCR analysis revealed that the expression level of CaCP gene was dramatically higher in leaves and flowers than that in roots, stems and fruits. Moreover, CaCP transcripts were induced upon during leaf senescence. CaCP expression was upregulated by plant hormones, especially salicylic acid. CaCP was also significantly induced by abiotic and biotic stress treatments, including high salinity, mannitol and Phytophthora capsici. Loss of function of CaCP using the virus-induced gene-silencing technique in pepper plants led to enhanced tolerance to salt- and osmotic-induced stress. Taken together, these results suggest that CaCP is a senescence-associated gene, which is involved in developmental senescence and regulates salt- and osmotic-induced leaf senescence in pepper.

  19. Carbamylated low-density lipoprotein induces oxidative stress and accelerated senescence in human endothelial progenitor cells.

    Science.gov (United States)

    Carracedo, Julia; Merino, Ana; Briceño, Carolina; Soriano, Sagrario; Buendía, Paula; Calleros, Laura; Rodriguez, Mariano; Martín-Malo, Alejandro; Aljama, Pedro; Ramírez, Rafael

    2011-04-01

    Carbamylated low-density lipoprotein (cLDL) plays a role in atherosclerosis. In this study we evaluate the effect of uremia on LDL carbamylation and the effect of cLDL and oxidized LDL (oxLDL; 200 μg/ml) on number, function, and genomic stability of endothelial progenitor cells (EPCs) obtained from healthy volunteers. cLDL was generated after incubation of native LDL (nLDL) with uremic serum from patients with chronic kidney disease (CKD) stages 2-4. Oxidative stress was measured by flow cytometry and fluorescent microscopy, mitochondrial depolarization by flow cytometry, senescence by β-galactosidase activity and telomere length, and DNA damage by phosphorylated histone H2AX (γH2AX). The percentage of cLDL by uremic serum was related to the severity of CKD. Compared with nLDL, cLDL induced an increase in oxidative stress (62±5 vs. 8±3%, P<0.001) and cells with mitochondrial depolarization (73±7 vs. 9±5%, P<0.001), and a decrease in EPC proliferation and angiogenesis. cLDL also induced accelerated senescence (73±16 vs. 12±9%, P<0.001), which was associated with a decrease in the expression of γH2AX (62±9 vs. 5±3%, P<0.001). The degree of injury induced by cLDL was comparable to that observed with oxLDL. This study supports the hypothesis that cLDL triggers genomic damage in EPCs, resulting in premature senescence. We can, therefore, hypothesize that EPCs injury by cLDL contributes to an increase in atherosclerotic disease in CKD.

  20. Senescence and immortality in hepatocellular carcinoma.

    Science.gov (United States)

    Ozturk, Mehmet; Arslan-Ergul, Ayca; Bagislar, Sevgi; Senturk, Serif; Yuzugullu, Haluk

    2009-12-01

    Cellular senescence is a process leading to terminal growth arrest with characteristic morphological features. This process is mediated by telomere-dependent, oncogene-induced and ROS-induced pathways, but persistent DNA damage is the most common cause. Senescence arrest is mediated by p16(INK4a)- and p21(Cip1)-dependent pathways both leading to retinoblastoma protein (pRb) activation. p53 plays a relay role between DNA damage sensing and p21(Cip1) activation. pRb arrests the cell cycle by recruiting proliferation genes to facultative heterochromatin for permanent silencing. Replicative senescence that occurs in hepatocytes in culture and in liver cirrhosis is associated with lack of telomerase activity and results in telomere shortening. Hepatocellular carcinoma (HCC) cells display inactivating mutations of p53 and epigenetic silencing of p16(INK4a). Moreover, they re-express telomerase reverse transcriptase required for telomere maintenance. Thus, senescence bypass and cellular immortality is likely to contribute significantly to HCC development. Oncogene-induced senescence in premalignant lesions and reversible immortality of cancer cells including HCC offer new potentials for tumor prevention and treatment.

  1. Identification and characterization of MOR-CP, a cysteine protease induced by ozone and developmental senescence in maize (Zea mays L.) leaves.

    Science.gov (United States)

    Ahmad, Rafiq; Zuily-Fodil, Yasmine; Passaquet, Chantal; Bethenod, Olivier; Roche, Romain; Repellin, Anne

    2014-08-01

    Among the different classes of endoproteases, cysteine proteases are consistently associated with senescence, defense signaling pathways and cellular responses to abiotic stresses. The objectives of this work were to study the effects of various concentrations of ozone on gene expression and enzymatic activity for papain-like cysteine proteases (PLCPs), in the leaves of maize plants grown under field conditions. Leaves from ranks 12 and 10 (cob leaf) were harvested regularly over a long-term artificial ozone fumigation experiment (50 d). Tissues were tested for transcriptional and activity changes concerning cysteine proteases, using qRT-PCR for the newly identified ozone-responsive PLCP gene (Mor-CP) and synthetic oligopeptide Boc-Val-Leu-Lys-AMC as a PLCP-specific substrate, respectively. Results showed that developmental senescence induced a significant and progressive rise in CP activity, only in the older leaves 10 and had no effect on Mor-CP gene expression levels. On the other hand, ozone dramatically enhanced Mor-CP mRNA levels and global PLCP enzymatic activity in leaves 12 and 10, particularly toward the end of the treatment. Ozone impact was more pronounced in the older leaves 10. Together, these observations concurred to conclude that ozone stress enhances natural senescence processes, such as those related to proteolysis.

  2. Senescence hypothesis for the pathogenetic mechanism of chronic obstructive pulmonary disease.

    Science.gov (United States)

    Aoshiba, Kazutetsu; Nagai, Atsushi

    2009-12-01

    We report herein that pulmonary emphysematous lesions appear to be a dynamic phenomenon that involves not only the gradual loss of alveolar structure but also apoptosis, cellular proliferation, and cellular senescence. Cellular proliferation compensates for increased alveolar cell apoptosis in patients with chronic obstructive pulmonary disease (COPD). However, smoking, age, and the increased cell cycle turnover that compensates for apoptosis accelerate alveolar cell senescence, thereby halting cellular proliferation and tipping the balance toward apoptosis, which, in turn, promotes the formation of emphysematous lesions. As a result, alveolar cells disappear and the emphysematous lesions progress. At the same time, cellular senescence is believed to induce inflammation. More specifically, senescent alveolar cells induce inflammation by producing various inflammatory cytokines in tissue. Lymphocytes and Clara cells may also age more rapidly in the lungs of patients with COPD. Lymphocyte senescence may induce an autoimmune reaction and increase susceptibility to infection, and Clara cell senescence may impair airway regeneration as well as sustain airway inflammation. Thus, cellular senescence may be involved in arrested tissue repair, chronic inflammation, and increased susceptibility to infection, which are the typical features of COPD.

  3. Emerging roles of lncRNAs in senescence

    DEFF Research Database (Denmark)

    Montes Resano, Marta; Lund, Anders H

    2016-01-01

    Cellular senescence is a complex stress response that leads to an irreversible state of cell growth arrest. Senescence may be induced by different stimuli such as telomere shortening, DNA damage or oncogenic insult among others. Senescent cells are metabolically highly active producing a wealth...... of cytokines and chemokines that depending on the context may have a beneficial or deleterious impact on the organism. Senescence is considered a tightly regulated stress response that is largely governed by the p53/p21 and p16/Rb pathways. Many molecules have been identified as regulators of these two...... networks, such as transcription factors, chromatin modifiers and recently, non-coding RNAs. The expression level of several long non-coding RNAs is affected during different types of senescence, however, which of these are important for the biological function remains poorly understood. We review here our...

  4. Mitochondrial DNA deletion and impairment of mitochondrial biogenesis are mediated by reactive oxygen species in ionizing radiation-induced premature senescence

    Energy Technology Data Exchange (ETDEWEB)

    Eom, Hyeon Soo; Jung, U Hee; Jo, Sung Kee [Radiation Biotechnology Research Division, Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of); Kim, Young Sang [College of Natural Sciences, Chungnam National University, Daejeon (Korea, Republic of)

    2011-09-15

    Mitochondrial DNA (mtDNA) deletion is a well-known marker for oxidative stress and aging, and contributes to harmful effects in cultured cells and animal tissues. mtDNA biogenesis genes (NRF-1, TFAM) are essential for the maintenance of mtDNA, as well as the transcription and replication of mitochondrial genomes. Considering that oxidative stress is known to affect mitochondrial biogenesis, we hypothesized that ionizing radiation (IR)-induced reactive oxygen species (ROS) causes mtDNA deletion by modulating the mitochondrial biogenesis, thereby leading to cellular senescence. Therefore, we examined the effects of IR on ROS levels, cellular senescence, mitochondrial biogenesis, and mtDNA deletion in IMR-90 human lung fibroblast cells. Young IMR-90 cells at population doubling (PD) 39 were irradiated at 4 or 8 Gy. Old cells at PD55, and H2O2-treated young cells at PD 39, were compared as a positive control. The IR increased the intracellular ROS level, senescence-associated {beta}-galactosidase (SA-{beta}-gal) activity, and mtDNA common deletion (4977 bp), and it decreased the mRNA expression of NRF-1 and TFAM in IMR-90 cells. Similar results were also observed in old cells (PD 55) and H{sub 2}O{sub 2}-treated young cells. To confirm that a increase in ROS level is essential for mtDNA deletion and changes of mitochondrial biogenesis in irradiated cells, the effects of N-acetylcysteine (NAC) were examined. In irradiated and H{sub 2}O{sub 2}-treated cells, 5 mM NAC significantly attenuated the increases of ROS, mtDNA deletion, and SA-{beta}-gal activity, and recovered from decreased expressions of NRF-1 and TFAM mRNA. These results suggest that ROS is a key cause of IR-induced mtDNA deletion, and the suppression of the mitochondrial biogenesis gene may mediate this process.

  5. The thyroid hormone receptor β induces DNA damage and premature senescence

    Science.gov (United States)

    Zambrano, Alberto; García-Carpizo, Verónica; Gallardo, María Esther; Villamuera, Raquel; Gómez-Ferrería, Maria Ana; Pascual, Angel; Buisine, Nicolas; Sachs, Laurent M.; Garesse, Rafael

    2014-01-01

    There is increasing evidence that the thyroid hormone (TH) receptors (THRs) can play a role in aging, cancer and degenerative diseases. In this paper, we demonstrate that binding of TH T3 (triiodothyronine) to THRB induces senescence and deoxyribonucleic acid (DNA) damage in cultured cells and in tissues of young hyperthyroid mice. T3 induces a rapid activation of ATM (ataxia telangiectasia mutated)/PRKAA (adenosine monophosphate–activated protein kinase) signal transduction and recruitment of the NRF1 (nuclear respiratory factor 1) and THRB to the promoters of genes with a key role on mitochondrial respiration. Increased respiration leads to production of mitochondrial reactive oxygen species, which in turn causes oxidative stress and DNA double-strand breaks and triggers a DNA damage response that ultimately leads to premature senescence of susceptible cells. Our findings provide a mechanism for integrating metabolic effects of THs with the tumor suppressor activity of THRB, the effect of thyroidal status on longevity, and the occurrence of tissue damage in hyperthyroidism. PMID:24395638

  6. Radiation Promotes Colorectal Cancer Initiation and Progression by Inducing Senescence-Associated Inflammatory Responses

    Science.gov (United States)

    Kim, Sang Bum; Bozeman, Ronald; Kaisani, Aadil; Kim, Wanil; Zhang, Lu; Richardson, James A.; Wright, Woodring E.; Shay, Jerry W.

    2015-01-01

    Proton radiotherapy is becoming more common since protons induce more precise DNA damage at the tumor site with reduced side effects to adjacent normal tissues. However, the long-term biological effects of proton irradiation in cancer initiation compared to conventional photon irradiation are poorly characterized. In this study, using a human familial adenomatous polyposis syndrome susceptible mouse model, we show that whole body irradiation with protons are more effective in inducing senescence-associated inflammatory responses (SIR) which are involved in colon cancer initiation and progression. After proton irradiation, a subset of SIR genes (Troy, Sox17, Opg, Faim2, Lpo, Tlr2 and Ptges) and a gene known to be involved in invasiveness (Plat), along with the senescence associated gene (P19Arf) are markedly increased. Following these changes loss of Casein kinase Iα (CKIα) and induction of chronic DNA damage and TP53 mutations are increased compared to x-ray irradiation. Proton irradiation also increases the number of colonic polyps, carcinomas and invasive adenocarcinomas. Pretreatment with the non-steroidal anti-inflammatory drug, CDDO-EA, reduces proton irradiation associated SIR and tumorigenesis. Thus, exposure to proton irradiation elicits significant changes in colorectal cancer initiation and progression that can be mitigated using CDDO-EA. PMID:26477319

  7. Revealing the cellular metabolism and microstructural changes in vivo in senescing Acer saccharum leaves using two-photon FLIM and full-field OCM

    Science.gov (United States)

    Chakraborty, Sandeep; Anna, Tulsi; Kuo, Wen-Chuan; Chiou, Arthur

    2016-10-01

    Seasonal as well as climate changes have immense effect on bud burst, leaf color and leaf abscission. Autumn phenology of leaves is clearly distinguishable in deciduous plant leaves where the leaf color changes from green to red (leaf senescence). In this work, two-photon fluorescence lifetime imaging microscopy (2P-FLIM) and full-field optical coherence microscopy (FF-OCM) were applied to study mitochondrial activity and microstructural changes, respectively, in the senescence of Acer saccharum (Sugar maple) leaves. Fluorescence lifetime of reduced nicotinamide adenine dinucleotide phosphate [NAD(P)H] was recorded using 2P-FLIM to quantify the cellular metabolic changes. Compared to the green leaves, the red leaves showed a 19% increase (P face sectional images at 0.8 μm axial resolutions of the green and the red color Acer saccharum leaves via FF-OCM using white light emitting diode (WLED) showed a well-defined microstructure of epicuticular waxy layer in green leaves as compared to red leaves where disintegrated microstructure was observed. Our approach can potentially be used to correlate mitochondrial activity with epicuticular microstructural changes in senescing leaves and other biological tissues.

  8. Mitotic Stress Is an Integral Part of the Oncogene-Induced Senescence Program that Promotes Multinucleation and Cell Cycle Arrest

    Directory of Open Access Journals (Sweden)

    Dina Dikovskaya

    2015-09-01

    Full Text Available Oncogene-induced senescence (OIS is a tumor suppression mechanism that blocks cell proliferation in response to oncogenic signaling. OIS is frequently accompanied by multinucleation; however, the origin of this is unknown. Here, we show that multinucleate OIS cells originate mostly from failed mitosis. Prior to senescence, mutant H-RasV12 activation in primary human fibroblasts compromised mitosis, concordant with abnormal expression of mitotic genes functionally linked to the observed mitotic spindle and chromatin defects. Simultaneously, H-RasV12 activation enhanced survival of cells with damaged mitoses, culminating in extended mitotic arrest and aberrant exit from mitosis via mitotic slippage. ERK-dependent transcriptional upregulation of Mcl1 was, at least in part, responsible for enhanced survival and slippage of cells with mitotic defects. Importantly, mitotic slippage and oncogene signaling cooperatively induced senescence and key senescence effectors p21 and p16. In summary, activated Ras coordinately triggers mitotic disruption and enhanced cell survival to promote formation of multinucleate senescent cells.

  9. The hemibiotroph Colletotrichum graminicola locally induces photosynthetically active green islands but globally accelerates senescence on aging maize leaves.

    Science.gov (United States)

    Behr, Michael; Humbeck, Klaus; Hause, Gerd; Deising, Holger B; Wirsel, Stefan G R

    2010-07-01

    Typically, pathogenesis of the hemibiotroph Colletotrichum graminicola and defense responses of its host, Zea mays, are studied on young leaves. Equivalent studies have not been performed with leaves undergoing senescence, a situation that is relevant in the field. We discovered that, in contrast to anthracnose symptoms formed on young and mature leaves, green islands reminiscent of those known from obligate biotrophs were formed on senescing leaves. Microscopy revealed that the fungus grew in both symptoms from the epidermis towards the bundle sheath. In green islands, tissues remained intact for an extended time period. Imaging PAM (pulse-amplitude-modulation) fluorescence analyses revealed that photosynthesis is transiently maintained at green islands but declined in tissue surrounding the infection. In younger leaves however, photosynthesis was reduced only at infection sites. Support for the local modification of host physiology came from quantitative reverse transcription-polymerase chain reaction analyzing gene expression at high spatial resolution. Decreased transcript levels of the senescence markers see1 and ccp1 corroborated a pathogen-induced delay of senescence. Expression of several genes encoding proteins involved in photosynthesis was strongly reduced by infection. In contrast, transcript levels of incw1, encoding a cell-wall invertase, were increased 70-fold at green islands, suggesting that C. graminicola induced carbon sinks in senescing tissue.

  10. Expression of human cell cycle regulators in the primary cell line of the African savannah elephant (loxodonta africana) increases proliferation until senescence, but does not induce immortalization.

    Science.gov (United States)

    Fukuda, Tomokazu; Iino, Yuuka; Onuma, Manabu; Gen, Bando; Inoue-Murayama, Miho; Kiyono, Tohru

    2016-01-01

    The African savannah elephant (Loxodonta africana) is one of the critically endangered animals. Conservation of genetic and cellular resources is important for the promotion of wild life-related research. Although primary cultured cells are a useful model for the physiology and genomics of the wild-type animals, their distribution is restricted due to the limited number of cell divisions allowed in them. Here, we tried to immortalize a primary cell line of L. africana with by overexpressing human mutant form of cyclin-dependent kinase 4 (CDK4R24C), cyclin D, and telomerase (TERT). It has been shown before that the combination of human CDK4R24C, cyclin D, and TERT induces the efficient cellular immortalization of cells derived from humans, bovine, swine, and monkeys. Interestingly, although the combination of these three genes extended the cellular proliferation of the L. africana-derived cells, they did not induce cellular immortalization. This study suggest that control of cellular senescence in L. africana-derived cells would be different molecular mechanisms compared to those governing human, bovine, swine, and monkey cells.

  11. Germ line transmission of the Cdk4(R24C) mutation facilitates tumorigenesis and escape from cellular senescence.

    Science.gov (United States)

    Rane, Sushil G; Cosenza, Stephen C; Mettus, Richard V; Reddy, E Premkumar

    2002-01-01

    Mutations in CDK4 and its key kinase inhibitor p16(INK4a) have been implicated in the genesis and progression of familial human melanoma. The importance of the CDK4 locus in human cancer first became evident following the identification of a germ line CDK4-Arg24Cys (R24C) mutation, which abolishes the ability of CDK4 to bind to p16(INK4a). To determine the role of the Cdk4(R24C) germ line mutation in the genesis of other cancer types, we introduced the R24C mutation in the Cdk4 locus of mice by using Cre-loxP-mediated "knock-in" technology. Cdk4(R24C/R24C) mouse embryo fibroblasts (MEFs) displayed increased Cdk4 kinase activity resulting in hyperphosphorylation of all three members of the Rb family, pRb, p107, and p130. MEFs derived from Cdk4(R24C/R24C) mice displayed decreased doubling times, escape from replicative senescence, and escape sensitivity to contact-induced growth arrest. These MEFs also exhibited a high degree of susceptibility to oncogene-induced transformation, suggesting that the Cdk4(R24C) mutation can serve as a primary event in the progression towards a fully transformed phenotype. In agreement with the in vitro data, homozygous Cdk4(R24C/R24C) mice developed tumors of various etiology within 8 to 10 months of their life span. The majority of these tumors were found in the pancreas, pituitary, brain, mammary tissue, and skin. In addition, Cdk4(R24C/R24C) mice showed extraordinary susceptibility to carcinogens and developed papillomas within the first 8 to 10 weeks following cutaneous application of the carcinogens 9,10-di-methyl-1,2-benz[a]anthracene (DMBA) and 12-O-tetradecanoylphorbol-13-acetate (TPA). This report formally establishes that the activation of Cdk4 is sufficient to promote cancer in many tissues. The observation that a wide variety of tumors develop in mice harboring the Cdk4(R24C) mutation offers a genetic proof that Cdk4 activation may constitute a central event in the genesis of many types of cancers in addition to melanoma.

  12. NF1 loss induces senescence during human melanocyte differentiation in an iPSC-based model.

    Science.gov (United States)

    Larribere, Lionel; Wu, Huizi; Novak, Daniel; Galach, Marta; Bernhardt, Mathias; Orouji, Elias; Weina, Kasia; Knappe, Nathalie; Sachpekidis, Christos; Umansky, Ludmila; Beckhove, Philipp; Umansky, Viktor; De Schepper, Sofie; Kaufmann, Dieter; Ballotti, Robert; Bertolotto, Corine; Utikal, Jochen

    2015-07-01

    Neurofibromatosis type 1 (NF1) is a frequent genetic disease leading to the development of Schwann cell-derived neurofibromas or melanocytic lesions called café-au-lait macules (CALMs). The molecular mechanisms involved in CALMs formation remain largely unknown. In this report, we show for the first time pathophysiological mechanisms of abnormal melanocyte differentiation in a human NF1(+/-) -induced pluripotent stem cell (iPSC)-based model. We demonstrate that NF1 patient-derived fibroblasts can be successfully reprogrammed in NF1(+/-) iPSCs with active RAS signaling and that NF1 loss induces senescence during melanocyte differentiation as well as in patient's-derived CALMs, revealing a new role for NF1 in the melanocyte lineage.

  13. Ginsenoside Rg1 prevents cognitive impairment and hippocampus senescence in a rat model of D-galactose-induced aging.

    Directory of Open Access Journals (Sweden)

    Jiahong Zhu

    Full Text Available Neurogenesis continues throughout the lifetime in the hippocampus, while the rate declines with brain aging. It has been hypothesized that reduced neurogenesis may contribute to age-related cognitive impairment. Ginsenoside Rg1 is an active ingredient of Panax ginseng in traditional Chinese medicine, which exerts anti-oxidative and anti-aging effects. This study explores the neuroprotective effect of ginsenoside Rg1 on the hippocampus of the D-gal (D-galactose induced aging rat model. Sub-acute aging was induced in male SD rats by subcutaneous injection of D-gal (120 mg/kg·d for 42 days, and the rats were treated with ginsenoside Rg1 (20 mg/kg·d, intraperitoneally or normal saline for 28 days after 14 days of D-gal injection. In another group, normal male SD rats were treated with ginsenoside Rg1 alone (20 mg/kg·d, intraperitoneally for 28 days. It showed that administration of ginsenoside Rg1 significantly attenuated all the D-gal-induced changes in the hippocampus, including cognitive capacity, senescence-related markers and hippocampal neurogenesis, compared with the D-gal-treated rats. Further investigation showed that ginsenoside Rg1 protected NSCs/NPCs (neural stem cells/progenitor cells shown by increased level of SOX-2 expression; reduced astrocytes activation shown by decrease level of Aeg-1 expression; increased the hippocampal cell proliferation; enhanced the activity of the antioxidant enzymes GSH-Px (glutathione peroxidase and SOD (Superoxide Dismutase; decreased the levels of IL-1β, IL-6 and TNF-α, which are the proinflammatory cytokines; increased the telomere lengths and telomerase activity; and down-regulated the mRNA expression of cellular senescence associated genes p53, p21Cip1/Waf1 and p19Arf in the hippocampus of aged rats. Our data provides evidence that ginsenoside Rg1 can improve cognitive ability, protect NSCs/NPCs and promote neurogenesis by enhancing the antioxidant and anti-inflammatory capacity in the

  14. ARF functions as a melanoma tumor suppressor by inducing p53-independent senescence

    Science.gov (United States)

    Ha, Linan; Ichikawa, Takeshi; Anver, Miriam; Dickins, Ross; Lowe, Scott; Sharpless, Norman E.; Krimpenfort, Paul; DePinho, Ronald A.; Bennett, Dorothy C.; Sviderskaya, Elena V.; Merlino, Glenn

    2007-01-01

    Inactivation of the p53 pathway represents the most common molecular defect of human cancer. But in the setting of melanoma, a highly aggressive and invariably fatal malignancy in its advanced disseminated form, mutation/deletion of p53 is relatively rare, whereas its positive regulator ARF is often lost. Here, we show that genetic deficiency in Arf but not p53 facilitates rapid development of melanoma in a genetically engineered mouse model. This difference is accounted for, at least in part, by the unanticipated observation that, unlike fibroblasts, senescence control in melanocytes is strongly regulated by Arf and not p53. Moreover, oncogenic NRAS collaborates with deficiency in Arf, but not p53, to fully transform melanocytes. Our data demonstrate that ARF and p53, although linked in a common pathway, suppress tumorigenesis through distinct, lineage-dependent mechanisms and suggest that ARF helps restrict melanoma progression by executing the oncogene-induced senescence program in benign nevi. Thus, therapeutics designed to restore wild-type p53 function may be insufficient to counter melanoma and other malignancies in which ARF holds p53-independent tumor suppressor activity. PMID:17576930

  15. The sulfated polysaccharide fucoidan rescues senescence of endothelial colony-forming cells for ischemic repair.

    Science.gov (United States)

    Lee, Jun Hee; Lee, Sang Hun; Choi, Sung Hyun; Asahara, Takayuki; Kwon, Sang-Mo

    2015-06-01

    The efficacy of cell therapy using endothelial colony-forming cells (ECFCs) in the treatment of ischemia is limited by the replicative senescence of isolated ECFCs in vitro. Such senescence must therefore be overcome in order for such cell therapies to be clinically applicable. This study aimed to investigate the potential of sulfated polysaccharide fucoidan to rescue ECFCs from cellular senescence and to improve in vivo vascular repair by ECFCs. Fucoidan-preconditioning of senescent ECFCs was shown by flow cytometry to restore the expression of functional ECFC surface markers (CD34, c-Kit, VEGFR2, and CXCR4) and stimulate the in vitro tube formation capacity of ECFCs. Fucoidan also promoted the expression of cell cycle-associated proteins (cyclin E, Cdk2, cyclin D1, and Cdk4) in senescent ECFCs, significantly reversed cellular senescence, and increased the proliferation of ECFCs via the FAK, Akt, and ERK signaling pathways. Fucoidan was found to enhance the survival, proliferation, incorporation, and endothelial differentiation of senescent ECFCs transplanted in ischemic tissues in a murine hind limb ischemia model. Moreover, ECFC-induced functional recovery and limb salvage were markedly improved by fucoidan pretreatment of ECFCs. To our knowledge, the findings of our study are the first to demonstrate that fucoidan enhances the neovasculogenic potential of ECFCs by rescuing them from replicative cellular senescence. Pretreatment of ECFCs with fucoidan may thus provide a novel strategy for the application of senescent stem cells to therapeutic neovascularization.

  16. Suppression of Transforming Growth Factor-β Signaling Delays Cellular Senescence and Preserves the Function of Endothelial Cells Derived From Human Pluripotent Stem Cells.

    Science.gov (United States)

    Bai, Hao; Gao, Yongxing; Hoyle, Dixie L; Cheng, Tao; Wang, Zack Z

    2016-09-20

    : Transplantation of vascular cells derived from human pluripotent stem cells (hPSCs) offers an attractive noninvasive method for repairing the ischemic tissues and for preventing the progression of vascular diseases. Here, we found that in a serum-free condition, the proliferation rate of hPSC-derived endothelial cells is quickly decreased, accompanied with an increased cellular senescence, resulting in impaired gene expression of endothelial nitric oxide synthase (eNOS) and impaired vessel forming capability in vitro and in vivo. To overcome the limited expansion of hPSC-derived endothelial cells, we screened small molecules for specific signaling pathways and found that inhibition of transforming growth factor-β (TGF-β) signaling significantly retarded cellular senescence and increased a proliferative index of hPSC-derived endothelial cells. Inhibition of TGF-β signaling extended the life span of hPSC-derived endothelial and improved endothelial functions, including vascular network formation on Matrigel, acetylated low-density lipoprotein uptake, and eNOS expression. Exogenous transforming growth factor-β1 increased the gene expression of cyclin-dependent kinase inhibitors, p15(Ink4b), p16(Ink4a), and p21(CIP1), in endothelial cells. Conversely, inhibition of TGF-β reduced the gene expression of p15(Ink4b), p16(Ink4a), and p21(CIP1). Our findings demonstrate that the senescence of newly generated endothelial cells from hPSCs is mediated by TGF-β signaling, and manipulation of TGF-β signaling offers a potential target to prevent vascular aging.

  17. Id4 Promotes Senescence and Sensitivity to Doxorubicin-induced Apoptosis in DU145 Prostate Cancer Cells

    OpenAIRE

    Carey, Jason P; Knowell, Ashley Evans; Chinaranagari, Swathi; Chaudhary, Jaideep

    2013-01-01

    Inhibitor of differentiation proteins (Id1, 2, 3 and 4) are dominant negative regulators of basic helix loop helix transcription factors and play dominant roles in cancer cells, spanning several molecular pathways including senescence, invasion, metastasis, proliferation and apoptosis. In contrast to high Id1, Id2 and Id3 expression, the expression of Id4 is epigenetically silenced in prostate cancer. In the present study we demonstrated a novel role of Id4, that of promotion of cellular sene...

  18. Resistance to discodermolide, a microtubule-stabilizing agent and senescence inducer, is 4E-BP1–dependent

    OpenAIRE

    Chao, Suzan K.; Lin, Juan; Brouwer-Visser, Jurriaan; Smith, Amos B.; Horwitz, Susan Band; McDaid, Hayley M.

    2010-01-01

    Discodermolide is a microtubule-stabilizing agent that induces accelerated cell senescence. A discodermolide-resistant cell line, AD32, was generated from the human lung cancer cell line A549. We hypothesize that the major resistance mechanism in these cells is escape from accelerated senescence. AD32 cells have decreased levels of 4E-BP1 mRNA and protein, relative to the parental discodermolide-sensitive A549 cells. Lentiviral-mediated re-expression of wild-type 4E-BP1 in AD32 cells increase...

  19. MDM2 inhibitor nutlin-3a induces apoptosis and senescence in cutaneous T-cell lymphoma: Role of p53

    DEFF Research Database (Denmark)

    Manfé, Valentina; Biskup, Edyta Urszula; Johansen, Peter

    2012-01-01

    cell lines, P53 mutation analysis identified a homozygous nonsense mutation (R196Stop in Hut-78) and a homozygous missense mutation (G245S in SeAx). In MyLa2000, Mac1, and Mac2a carrying wild-type P53, nutlin-3a induced apoptosis and senescence demonstrated by permanent G0/G1 cell-cycle block...... and expression of the senescence-associated β-galactosidase. This effect was abolished in cells in which p53 was silenced by small interfering RNA. Sézary cells lack functional p53 and were resistant to nutlin-3a. However, nutlin-3a potentiated the efficacy of conventional chemotherapeutics not only in cells...... with intact p53 but also in Hut-78, SeAx, and Sézary cells. Thus, targeting p53 by nutlin-3a may constitute a therapeutic approach in CTCL because of increased apoptosis and senescence of tumor cells....

  20. Sensitive detection and monitoring of senescence-associated secretory phenotype by SASP-RAP assay.

    Science.gov (United States)

    Gu, Liubao; Kitamura, Masanori

    2012-01-01

    Senescence-associated secretory phenotype (SASP) is characterized by abundant secretion of various proteins in senescent cells and implicated in tumor progression and inflammatory responses. However, the profile of secreted proteins in SASP is different from cell type to cell type, and currently, universal markers for SASP have not been reported. In the present investigation, we show that SASP-responsive alkaline phosphatase (SASP-RAP) serves as a sensitive, general and convenient marker for SASP. Etoposide-treated cells exhibited a senescent phenotype characterized by senile morphology, positive staining for senescence-associated β-galactosidase, growth arrest and induction of p53 and p21(WAF1/CIP1). In SASP-RAP-transfected cells, exposure to etoposide increased secretion of SASP-RAP time-dependently. The kinetics of secretion was closely correlated with that of activation of the p21(WAF1/CIP1) promoter and the p16(INK4a) promoter. The enhanced secretion of SASP-RAP by senescence was also observed in cells treated with other senescence inducers such as trichostatin A, doxorubicin and 4-phenylbutylic acid. The induction of SASP-RAP by senescence was similarly observed in natural replicative senescence. To confirm selectivity of the SASP-RAP response, cells were treated with senescence-related and -unrelated stimuli (IL-1β, LPS, TNF-α and TGF-β), and induction of senescence markers and activity of SASP-RAP were evaluated in parallel. Unlike etoposide, senescence-unrelated stimuli did not induce p53 and p21(WAF1/CIP1), and it was correlated with lack of induction of SASP-RAP. In contrast, senescence-unrelated stimuli up-regulated conventional indicators for SASP, e.g., MMP-3, IL-6 and TIMP, without induction of senescence. SASP-RAP thus serves as a selective, convenient and general marker for detection and monitoring of SASP during cellular senescence.

  1. [Stress-induced cellular adaptive mutagenesis].

    Science.gov (United States)

    Zhu, Linjiang; Li, Qi

    2014-04-01

    The adaptive mutations exist widely in the evolution of cells, such as antibiotic resistance mutations of pathogenic bacteria, adaptive evolution of industrial strains, and cancerization of human somatic cells. However, how these adaptive mutations are generated is still controversial. Based on the mutational analysis models under the nonlethal selection conditions, stress-induced cellular adaptive mutagenesis is proposed as a new evolutionary viewpoint. The hypothetic pathway of stress-induced mutagenesis involves several intracellular physiological responses, including DNA damages caused by accumulation of intracellular toxic chemicals, limitation of DNA MMR (mismatch repair) activity, upregulation of general stress response and activation of SOS response. These responses directly affect the accuracy of DNA replication from a high-fidelity manner to an error-prone one. The state changes of cell physiology significantly increase intracellular mutation rate and recombination activity. In addition, gene transcription under stress condition increases the instability of genome in response to DNA damage, resulting in transcription-associated DNA mutagenesis. In this review, we summarize these two molecular mechanisms of stress-induced mutagenesis and transcription-associated DNA mutagenesis to help better understand the mechanisms of adaptive mutagenesis.

  2. Use of inductor agents GSE24.2 for producing pharmaceutical compositions for treating illnesses relating to cellular senescence

    OpenAIRE

    2010-01-01

    This invention relates to the use of an inductor or activator compound GSE24.2 for producing a medicament or a pharmaceutical composition for treating a preferably human illness or pathological situation caused by a senescence process. Said pharmaceutical composition can be useful for a treatment for regenerating tissues, for example of epithelial tissues or haematopoietic cells, and also for the immortalisation of eucaryotic cells in order to use of same in biotechnological investigation or ...

  3. Dysfunctional lipoproteins from young smokers exacerbate cellular senescence and atherogenesis with smaller particle size and severe oxidation and glycation.

    Science.gov (United States)

    Park, Ki-Hoon; Shin, Dong-Gu; Cho, Kyung-Hyun

    2014-07-01

    Until now, there has been limited information on the effects of smoking on atherogenesis and senescence in the context of lipoprotein parameters, particularly in young smokers who have smoked fewer than 10 cigarettes per day for 3 years. In this study, lipoprotein profiles and functions were compared between smoker (n = 21) and control groups (n = 20). In the smoking group, ferric ion reduction abilities of serum and high-density lipoprotein (HDL) fractions were significantly reduced, and low-density lipoprotein (LDL) was severely oxidized. All lipoprotein particles from the smoker group showed higher advanced glycated end products with more triglyceride (TG) content compared with the control group. Lipoproteins from smokers showed faster agarose gel electromobility as well as greater smear band intensity in SDS-PAGE due to oxidation and glycation. LDL from smokers was more sensitive to oxidation and promoted foam cell forma-tion in macrophages. Gel filtration column chromatography revealed that the protein and cholesterol peaks of VLDL and LDL were elevated in the smoker group, whereas those of HDL were reduced. Human dermal fibroblast cells from the smoker group showed severe senescence following treatment with HDL2 and HDL3. Although HDL from young smokers showed impaired antioxidant ability, smaller particle size, and increased TG content, cholesteryl ester transfer protein activities were greatly enhanced in the serum and HDL fractions of the smoker group. In conclusion, smoking can cause production of dysfunctional lipoproteins having a smaller particle size that exacerbate senescence and atherogenic progress due to oxidation and glycation.

  4. Obesity-induced gut microbial metabolite promotes liver cancer through senescence secretome.

    Science.gov (United States)

    Yoshimoto, Shin; Loo, Tze Mun; Atarashi, Koji; Kanda, Hiroaki; Sato, Seidai; Oyadomari, Seiichi; Iwakura, Yoichiro; Oshima, Kenshiro; Morita, Hidetoshi; Hattori, Masahira; Hattori, Masahisa; Honda, Kenya; Ishikawa, Yuichi; Hara, Eiji; Ohtani, Naoko

    2013-07-04

    Obesity has become more prevalent in most developed countries over the past few decades, and is increasingly recognized as a major risk factor for several common types of cancer. As the worldwide obesity epidemic has shown no signs of abating, better understanding of the mechanisms underlying obesity-associated cancer is urgently needed. Although several events were proposed to be involved in obesity-associated cancer, the exact molecular mechanisms that integrate these events have remained largely unclear. Here we show that senescence-associated secretory phenotype (SASP) has crucial roles in promoting obesity-associated hepatocellular carcinoma (HCC) development in mice. Dietary or genetic obesity induces alterations of gut microbiota, thereby increasing the levels of deoxycholic acid (DCA), a gut bacterial metabolite known to cause DNA damage. The enterohepatic circulation of DCA provokes SASP phenotype in hepatic stellate cells (HSCs), which in turn secretes various inflammatory and tumour-promoting factors in the liver, thus facilitating HCC development in mice after exposure to chemical carcinogen. Notably, blocking DCA production or reducing gut bacteria efficiently prevents HCC development in obese mice. Similar results were also observed in mice lacking an SASP inducer or depleted of senescent HSCs, indicating that the DCA-SASP axis in HSCs has key roles in obesity-associated HCC development. Moreover, signs of SASP were also observed in the HSCs in the area of HCC arising in patients with non-alcoholic steatohepatitis, indicating that a similar pathway may contribute to at least certain aspects of obesity-associated HCC development in humans as well. These findings provide valuable new insights into the development of obesity-associated cancer and open up new possibilities for its control.

  5. SU5416 induces premature senescence in endothelial progenitor cells from patients with age-related macular degeneration

    Science.gov (United States)

    Berna, Marc J.; Kunst, Frank; Wege, Henning; Strunnikova, Natalya V.; Gordiyenko, Natalya; Grierson, Rebecca; Richard, Gisbert; Csaky, Karl G.

    2011-01-01

    Purpose We recently demonstrated increased frequency and growth potential of late outgrowth endothelial progenitor cells (OECs) in patients with neovascular age-related macular degeneration (nvAMD). This study investigated the effects of short- and long-term in vitro inhibition of vascular endothelial growth factor (VEGF) Receptor-2 (VEGFR-2) signaling by SU5416 and other inhibitors of the VEGF signaling pathway in OECs. Methods OECs, from the peripheral blood of patients with nvAMD, and human umbilical vein endothelial cells were grown in the presence of SU5416, other VEGFR-2 tyrosine kinase inhibitors (TKIs), and inhibitors of phosphatidylinositol 3′-Kinase (PI3K)/protein kinase B (Akt) and protein kinase C (PKC) in complete angiogenic medium. Apotosis was assessed after 48 h using the fluorescein isothiocyanate Annexin V method. Cell counts were performed for 10 days, and features of senescence were analyzed using senescence-associated β-galactosidase staining, the telomeric repeat amplification protocol for telomerase activity, Southern blot analysis for mean telomere length, flow cytometric analysis for cell-cycle arrest, and western blot for p53 and p21. Control OECs, cells treated for 7 days with inhibitors, as well as naturally senescent OECs were analyzed for expression of different endothelial antigens, including VEGFR-2 and the receptor for stromal cell-derived factor 1, chemokine receptor 4 (CXCR-4). Migration in vitro to VEGF and stromal cell-derived factor 1 of OECs was assessed. Results SU5416, other VEGFR-2 TKIs, and inhibitors of PI3K, Akt, and PKC induced apoptosis, inhibited long-term proliferation, reduced telomerase activity, and induced premature senescence and cell-cycle arrest in OECs as well as in human umbilical vein endothelial cells. Naturally senescent cells and cells rendered senescent by VEGFR-2 TKIs had reduced VEGFR-2 and CXCR-4 expression and demonstrated reduced migratory ability to VEGF. Conclusions This study demonstrates

  6. MicroRNA-33 promotes the replicative senescence of mouse embryonic fibroblasts by suppressing CDK6

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Shun; Huang, Haijiao; Li, Nanhong; Zhang, Bing; Jia, Yubin; Yang, Yukun; Yuan, Yuan; Xiong, Xing-dong; Wang, Dengchuan; Zheng, Hui-ling [Institute of Aging Research, Guangdong Medical University, Dongguan (China); Guangdong Provincial Key Laboratory of Medical Molecular Diagnostics, Dongguan (China); Institute of Biochemistry & Molecular Biology, Guangdong Medical University, Zhanjiang (China); Liu, Xinguang, E-mail: xgliu64@126.com [Institute of Aging Research, Guangdong Medical University, Dongguan (China); Guangdong Provincial Key Laboratory of Medical Molecular Diagnostics, Dongguan (China); Institute of Biochemistry & Molecular Biology, Guangdong Medical University, Zhanjiang (China)

    2016-05-13

    MicroRNAs are a large class of tiny noncoding RNAs, which have emerged as critical regulators of gene expression, and thus are involved in multiple cellular processes, including cellular senescence. MicroRNA-33 has previously been established to exert crucial effect on cell proliferation, lipid metabolism and cholesterol metabolism. Nonetheless, the association between microRNA-33 and cellular senescence and its underlying molecular mechanism are far to be elucidated. The present study has attempted to probe into the effect of microRNA-33 on MEFs senescence. Our data unveiled that microRNA-33 was dramatically down-regulated in senescent MEFs compared to the young MEFs, and ectopic expression of microRNA-33 promoted MEFs senescence, while knock-down of microRNA-33 exhibited a protective effect against senescence phenotype. Moreover, we verified CDK6 as a direct target of microRNA-33 in mouse. Silencing of CDK6 induced the premature senescence phenotype of MEFs similarly as microRNA-33, while enforced expression of CDK6 significantly reverse the senescence-induction effect of microRNA-33. Taken together, our results suggested that microRNA-33 enhanced the replicative senescence of MEFs potentially by suppressing CDK6 expression. -- Highlights: •MicroRNA-33 was dramatically down-regulated in senescent MEF cells. •Altered expression of microRNA-33 exerted a critical role in MEFs senescence. •MicroRNA-33 promoted the replicative senescence of MEFs via targeting of CDK6.

  7. Resistance to discodermolide, a microtubule-stabilizing agent and senescence inducer, is 4E-BP1-dependent.

    Science.gov (United States)

    Chao, Suzan K; Lin, Juan; Brouwer-Visser, Jurriaan; Smith, Amos B; Horwitz, Susan Band; McDaid, Hayley M

    2011-01-01

    Discodermolide is a microtubule-stabilizing agent that induces accelerated cell senescence. A discodermolide-resistant cell line, AD32, was generated from the human lung cancer cell line A549. We hypothesize that the major resistance mechanism in these cells is escape from accelerated senescence. AD32 cells have decreased levels of 4E-BP1 mRNA and protein, relative to the parental discodermolide-sensitive A549 cells. Lentiviral-mediated re-expression of wild-type 4E-BP1 in AD32 cells increased the proliferation rate and reverted resistance to discodermolide via restoration of discodermolide-induced accelerated senescence. Consistent with this, cell growth and response to discodermolide was confirmed in vivo using tumor xenograft models. Furthermore, reintroduction of a nonphosphorylatable mutant (Thr-37/46 Ala) of 4E-BP1 was able to partially restore sensitivity and enhance proliferation in AD32 cells, suggesting that these effects are independent of phosphorylation by mTORC1. Microarray profiling of AD32-resistant cells versus sensitive A549 cells, and subsequent unbiased gene ontology analysis, identified molecular pathways and functional groupings of differentially expressed mRNAs implicated in overcoming discodermolide-induced senescence. The most statistically significant classes of differentially expressed genes included p53 signaling, G2/M checkpoint regulation, and genes involved in the role of BRCA1 in the DNA damage response. Consistent with this, p53 protein expression was up-regulated and had increased nuclear localization in AD32 cells relative to parental A549 cells. Furthermore, the stability of p53 was enhanced in AD32 cells. Our studies propose a role for 4E-BP1 as a regulator of discodermolide-induced accelerated senescence.

  8. Knockdown of CDK2AP1 in primary human fibroblasts induces p53 dependent senescence.

    Directory of Open Access Journals (Sweden)

    Khaled N Alsayegh

    knockdown. Altogether, our results show that knockdown of CDK2AP1 in primary human fibroblasts reduced proliferation and induced premature senescence, with the observed phenotype being p53 dependent.

  9. Silence of long noncoding RNA PANDAR switches low-dose curcumin-induced senescence to apoptosis in colorectal cancer cells

    Directory of Open Access Journals (Sweden)

    Chen T

    2017-01-01

    Full Text Available Tao Chen,1,* Peng Yang,1,* Hui Wang,1 Zhen-Yu He2 1Department of General Surgery, The Second Clinical Medical College of Nanjing Medical University, 2Department of General Surgery, The Second Affiliated Hospital of Nanjing Medical University, Nanjing, Jiangsu, People’s Republic of China *These authors contributed equally to this work Abstract: Long noncoding RNAs (lncRNAs are emerging as having multiple roles in cancer progression. However, roles of lncRNAs in chemotherapy for colorectal cancer (CRC remain unclear. This study investigated the biological functions of lncRNA PANDAR in CRC cells treated with curcumin chemotherapy. Herein, we identified that PANDAR expression was not notably differential in CRC tissues compared with the corresponding normal tissues. Consistently, in vitro experiments revealed that knockdown of PANDAR could not change the proliferation, apoptosis, or senescence of CRC cells. Further analyses showed that low-dose curcumin could induce senescence in CRC cells without affecting cell apoptosis. Moreover, expression of PANDAR was increased in curcumin-treated CRC cells. Furthermore, silencing PANDAR in curcumin-treated cells increased apoptosis and greatly attenuated senescence possibly by stimulating the expression of PUMA. Together, these findings indicate that knockdown of lncRNA PANDAR switches curcumin-induced senescence to apoptosis, which may be potentially valuable in CRC therapy. Keywords: colorectal cancer, long noncoding RNA, PANDAR, curcumin, chemotherapy

  10. Evolution of plant senescence

    Directory of Open Access Journals (Sweden)

    Young Mike

    2009-07-01

    characteristics of senescence-related genes allow a framework to be constructed of decisive events in the evolution of the senescence syndrome of modern land-plants. Combining phylogenetic, comparative sequence, gene expression and morphogenetic information leads to the conclusion that biochemical, cellular, integrative and adaptive systems were progressively added to the ancient primary core process of senescence as the evolving plant encountered new environmental and developmental contexts.

  11. Angelica Sinensis Polysaccharide Prevents Hematopoietic Stem Cells Senescence in D-Galactose-Induced Aging Mouse Model

    Directory of Open Access Journals (Sweden)

    Xinyi Mu

    2017-01-01

    Full Text Available Age-related regression in hematopoietic stem/progenitor cells (HSC/HPCs limits replenishment of the blood and immune system and hence contributes to hematopoietic diseases and declined immunity. In this study, we employed D-gal-induced aging mouse model and observed the antiaging effects of Angelica Sinensis Polysaccharide (ASP, a major active ingredient in dong quai (Chinese Angelica Sinensis, on the Sca-1+ HSC/HPCs in vivo. ASP treatment prevents HSC/HPCs senescence with decreased AGEs levels in the serum, reduced SA-β-Gal positive cells, and promoted CFU-Mix formation in the D-gal administrated mouse. We further found that multiple mechanisms were involved: (1 ASP treatment prevented oxidative damage as total antioxidant capacity was increased and levels of reactive oxygen species (ROS, 8-OHdG, and 4-HNE were declined, (2 ASP reduced the expression of γ-H2A.X which is a DNA double strand breaks (DSBs marker and decreased the subsequent ectopic expressions of effectors in p16Ink4a-RB and p19Arf-p21Cip1/Waf senescent pathways, and (3 ASP inhibited the excessive activation of Wnt/β-catenin signaling in aged HSC/HPCs, as the expressions of β-catenin, phospho-GSK-3β, and TCF-4 were decreased, and the cyto-nuclear translocation of β-catenin was inhibited. Moreover, compared with the positive control of Vitamin E, ASP exhibited a better antiaging effect and a weaker antioxidation ability, suggesting a novel protective role of ASP in the hematopoietic system.

  12. Drying Without Senescence in Resurrection Plants

    Directory of Open Access Journals (Sweden)

    Cara Ashleigh Griffiths

    2014-02-01

    Full Text Available Research into extreme drought tolerance in resurrection plants using species such as Craterostigma plantagineum, Craterostigma wilmsii, Xerophyta humilis, Tortula ruralis and Sporobolus stapfianus has provided some insight into the desiccation tolerance mechanisms utilized by these plants to allow them to persist under extremely adverse environmental conditions. Some of the mechanisms used to ensure cellular preservation during severe dehydration appear to be peculiar to resurrection plants. Apart from the ability to preserve vital cellular components during drying and rehydration, such mechanisms include the ability to down-regulate growth-related metabolism rapidly in response to changes in water availability, and the ability to inhibit dehydration-induced senescence programs enabling reconstitution of photosynthetic capacity quickly following a rainfall event. Currently, very little is known about the molecular mechanisms that resurrection plants employ to avoid undergoing drought-related senescence during the desiccation process. To survive desiccation, dehydration in the perennial resurrection grass S. stapfianus must proceed slowly over a period of 7 days or more. Leaves detached from the plant before 60% relative water content (RWC is attained are desiccation-sensitive indicating that desiccation tolerance is conferred in vegetative tissue of S. stapfianus when the leaf RWC has declined to 60%. Whilst some older leaves remaining attached to the plant during dehydration will senesce, suggesting dehydration-induced senescence may be influenced by leaf age or the rate of dehydration in individual leaves, the majority of leaves do not senesce. Rather these leaves dehydrate to air-dryness and revive fully following rehydration. Hence it seems likely that there are genes expressed in younger leaf tissues of resurrection plants that enable suppression of drought-related senescence pathways. As very few studies have directly addressed this

  13. Nanog induces suppression of senescence through downregulation of p27KIP1 expression

    Science.gov (United States)

    Münst, Bernhard; Thier, Marc Christian; Winnemöller, Dirk; Helfen, Martina; Thummer, Rajkumar P.; Edenhofer, Frank

    2016-01-01

    ABSTRACT A comprehensive analysis of the molecular network of cellular factors establishing and maintaining pluripotency as well as self renewal of pluripotent stem cells is key for further progress in understanding basic stem cell biology. Nanog is necessary for the natural induction of pluripotency in early mammalian development but dispensable for both its maintenance and its artificial induction. To gain further insight into the molecular activity of Nanog, we analyzed the outcomes of Nanog gain-of-function in various cell models employing a recently developed biologically active recombinant cell-permeant protein, Nanog-TAT. We found that Nanog enhances the proliferation of both NIH 3T3 and primary fibroblast cells. Nanog transduction into primary fibroblasts results in suppression of senescence-associated β-galactosidase activity. Investigation of cell cycle factors revealed that transient activation of Nanog correlates with consistent downregulation of the cell cycle inhibitor p27KIP1 (also known as CDKN1B). By performing chromatin immunoprecipitation analysis, we confirmed bona fide Nanog-binding sites upstream of the p27KIP1 gene, establishing a direct link between physical occupancy and functional regulation. Our data demonstrates that Nanog enhances proliferation of fibroblasts through transcriptional regulation of cell cycle inhibitor p27 gene. PMID:26795560

  14. ABI3 ectopic expression reduces in vitro and in vivo cell growth properties while inducing senescence

    Directory of Open Access Journals (Sweden)

    Riggins Gregory J

    2011-01-01

    Full Text Available Abstract Background Mounting evidence has indicated that ABI3 (ABI family member 3 function as a tumor suppressor gene, although the molecular mechanism by which ABI3 acts remains largely unknown. Methods The present study investigated ABI3 expression in a large panel of benign and malignant thyroid tumors and explored a correlation between the expression of ABI3 and its potential partner ABI3-binding protein (ABI3BP. We next explored the biological effects of ABI3 ectopic expression in thyroid and colon carcinoma cell lines, in which its expression was reduced or absent. Results We not only observed that ABI3 expression is reduced or lost in most carcinomas but also that there is a positive correlation between ABI3 and ABI3BP expression. Ectopic expression of ABI3 was sufficient to lead to a lower transforming activity, reduced tumor in vitro growth properties, suppressed in vitro anchorage-independent growth and in vivo tumor formation while, cellular senescence increased. These responses were accompanied by the up-regulation of the cell cycle inhibitor p21 WAF1 and reduced ERK phosphorylation and E2F1 expression. Conclusions Our result links ABI3 to the pathogenesis and progression of some cancers and suggests that ABI3 or its pathway might have interest as therapeutic target. These results also suggest that the pathways through which ABI3 works should be further characterized.

  15. Role of cellular senescence and apoptosis in kidney development%细胞衰老与凋亡在肾脏发育中的作用

    Institute of Scientific and Technical Information of China (English)

    李清刚; 谢院生; 陈香美

    2014-01-01

    Senescence is a normal process in the embryonic development,which is involved in embryonic tissue remodeling,tissue development,and morphogenesis,as a programmed aging mechanism during development.As different cellular processes,senescence and apoptosis are closely related to each other.Apoptosis plays an important role during the ureter development.Apoptosis in common nephric duct (CND)occurs normally during development to make the ureteral orifice separate from Wolffian duct (WD) and then fuse with the bladder epithelium,which leads to normal ureter development.%衰老是胚胎发育过程中的一种正常的程序,参与胚胎发育的组织重构、组织发育和形态上发生,属于发育程序性衰老机制。作为不同的细胞过程,衰老与凋亡密切相关。在输尿管发育过程中,凋亡具有重要作用,胚胎肾管(CND)发生正常凋亡使得输尿管口与中肾管(WD)分离并与膀胱上皮融合,维持正常输尿管发育以及与膀胱接口正常。

  16. Down-regulation of OsSAG12-1 results in enhanced senescence and pathogen-induced cell death in transgenic rice plants

    Indian Academy of Sciences (India)

    Subaran Singh; Mrunmay Kumar Giri; Praveen Kumar Singh; Adnan Siddiqui; Ashis Kumar Nandi

    2013-09-01

    Senescence is a highly regulated process accompanied by changes in gene expression. While the mRNA levels of most genes decline, the mRNA levels of specific genes (senescence associated genes, SAGs) increase during senescence. Arabidopsis SAG12 (AtSAG12) gene codes for papain-like cysteine protease. The promoter of AtSAG12 is SA-responsive and reported to be useful to delay senescence by expressing cytokinin biosynthesis gene isopentenyltransferase specifically during senescence in several plants including Arabidopsis, lettuce and rice. The physiological role of AtSAG12 is not known; the homozygous atsag12 mutant neither fails to develop senescence-associated vacuoles nor shows any morphological phenotype. Through BLAST search using AtSAG12 amino acid sequences as query, we identified a few putative homologues from rice genome (OsSAGs; Oryza sativa SAGs). OsSAG12-1 is the closest homologue of AtSAG12 with 64% similar amino acid composition. Expression of OsSAG12-1 is induced during senescence and pathogen-induced cell death. To evaluate the possible role of OsSAG12-1 we generated RNAi transgenic lines in Japonica rice cultivar TP309. The transgenic lines developed early senescence at varying levels and showed enhanced cell death when inoculated with bacterial pathogen Xanthomonas oryzae pv.oryzae. Our results suggest that OsSAG12-1 is a negative regulator of cell death in rice.

  17. p53 is required for metformin-induced growth inhibition, senescence and apoptosis in breast cancer cells.

    Science.gov (United States)

    Li, Puyu; Zhao, Ming; Parris, Amanda B; Feng, Xiaoshan; Yang, Xiaohe

    2015-09-04

    The p53 tumor repressor gene is commonly mutated in human cancers. The tumor inhibitory effect of metformin on p53-mutated breast cancer cells remains unclear. Data from the present study demonstrated that p53 knockdown or mutation has a negative effect on metformin or phenformin-induced growth inhibition, senescence and apoptosis in breast cancer cells. We also found that p53 reactivating agent nutlin-3α and CP/31398 promoted metformin-induced growth inhibition, senescence and apoptosis in MCF-7 (wt p53) and MDA-MB-231 (mt p53) cells, respectively. Treatment of MCF-7 cells with metformin or phenformin induced increase in p53 protein levels and the transcription of its downstream target genes, Bax and p21, in a dose-dependent manner. Moreover, we demonstrated that AMPK-mTOR signaling played a role in metformin-induced p53 up-regulation. The present study showed that p53 is required for metformin or phenformin-induced growth inhibition, senescence and apoptosis in breast cancer cells. The combination of metformin with p53 reactivating agents, like nutlin-3α and CP/31398, is a promising strategy for improving metformin-mediated anti-cancer therapy, especially for tumors with p53 mutations.

  18. Senescence Meets Dedifferentiation

    Directory of Open Access Journals (Sweden)

    Yemima Givaty Rapp

    2015-06-01

    Full Text Available Senescence represents the final stage of leaf development but is often induced prematurely following exposure to biotic and abiotic stresses. Leaf senescence is manifested by color change from green to yellow (due to chlorophyll degradation or to red (due to de novo synthesis of anthocyanins coupled with chlorophyll degradation and frequently culminates in programmed death of leaves. However, the breakdown of chlorophyll and macromolecules such as proteins and RNAs that occurs during leaf senescence does not necessarily represent a one-way road to death but rather a reversible process whereby senescing leaves can, under certain conditions, re-green and regain their photosynthetic capacity. This phenomenon essentially distinguishes senescence from programmed cell death, leading researchers to hypothesize that changes occurring during senescence might represent a process of trans-differentiation, that is the conversion of one cell type to another. In this review, we highlight attributes common to senescence and dedifferentiation including chromatin structure and activation of transposable elements and provide further support to the notion that senescence is not merely a deterioration process leading to death but rather a unique developmental state resembling dedifferentiation.

  19. The splicing factor ASF/SF2 and intron retention as markers of endothelial senescence

    Directory of Open Access Journals (Sweden)

    Francisco Javier Blanco

    2012-03-01

    Full Text Available Aging is the major risk factor per se for the development of cardiovascular diseases. The senescence of endothelial cells, that line the lumen of blood vessels, is at the cellular basis of these age-dependent vascular pathologies, including atherosclerosis and hypertension. Along their lifespan, endothelial cells may reach the senescence stage by two different pathways, the replicative one derived from their finite number of divisions, and the one induced by stress stimuli. Also, certain physiological stimuli, such as TGF-β are able to modulate cellular senescence. Currently, the cellular aging process is being widely studied to identify novel molecular markers whose changes correlate with senescence. This review focuses on the regulation of alternative splicing mediated by the serine-arginine splicing factor 1 (SRSF1, or ASF/SF2 during endothelial senescence, a process that is associated with a differential subcellular localization of SRSF1, showing a scattered distribution throughout the cytoplasm. Based on its senescence-dependent involvement in alternative splicing, we postulate that SRSF1 is a key marker of endothelial cell senescence regulating the expression of alternative isoforms of target genes such as ENG, VEGFA, T3 or LMNA that integrate a common molecular senescence program.

  20. N-Methyl-N'-nitro-N-nitrosoguanidine-induced senescence-like growth arrest in colon cancer cells is associated with loss of adenomatous polyposis coli protein, microtubule organization, and telomeric DNA

    Directory of Open Access Journals (Sweden)

    Narayan Satya

    2004-01-01

    Full Text Available Abstract Background Cellular senescence is a state in which mammalian cells enter into an irreversible growth arrest and altered biological functions. The senescence response in mammalian cells can be elicited by DNA-damaging agents. In the present study we report that the DNA-damaging agent N-methyl-N'-nitro-N-nitrosoguanidine (MNNG is able to induce senescence in the HCT-116 colon cancer cell line. Results Cells treated with lower concentrations of MNNG (0–25 microM for 50 h showed a dose-dependent increase in G2/M phase arrest and apoptosis; however, cells treated with higher concentrations of MNNG (50–100 microM showed a senescence-like G0/G1 phase arrest which was confirmed by increased expression of β-galactosidase, a senescence induced marker. The G2/M phase arrest and apoptosis were found to be associated with increased levels of p53 protein, but the senescence-like G0/G1 phase arrest was dissociated with p53 protein levels, since the p53 protein levels decreased in senescence-like arrested cells. We further, determined whether the decreased level of p53 was a transcriptional or a translational phenomenon. The results revealed that the decreased level of p53 protein in senescence-like arrested cells was a transcriptional phenomenon since p53 mRNA levels simultaneously decreased after treatment with higher concentrations of MNNG. We also examined the effect of MNNG treatment on other cell cycle-related proteins such as p21, p27, cyclin B1, Cdc2, c-Myc and max. The expression levels of these proteins were increased in cells treated with lower concentrations of MNNG, which supported the G2/M phase arrest. However, cells treated with higher concentrations of MNNG showed decreased levels of these proteins, and hence, may not play a role in cell cycle arrest. We then examined a possible association of the expression of APC protein and telomeric DNA signals with cellular senescence in MNNG-treated cells. We found that protein and m

  1. Transcriptional factor HBP1 targets P16(INK4A), upregulating its expression and consequently is involved in Ras-induced premature senescence.

    Science.gov (United States)

    Li, H; Wang, W; Liu, X; Paulson, K E; Yee, A S; Zhang, X

    2010-09-09

    Oncogene-mediated premature senescence has emerged as a potential tumor-suppressive mechanism in early cancer transitions. Many studies showed that Ras and p38 mitogen-activated protein kinase (MAPK) participate in premature senescence. Our previous work indicated that the HMG box-containing protein 1 (HBP1) transcription factor is involved in Ras- and p38 MAPK-induced premature senescence, but the mechanism of which has not yet been identified. Here, we showed that the p16(INK4A) cyclin-dependent kinase inhibitor is a novel target of HBP1 participating in Ras-induced premature senescence. The promoter of the p16(INK4A) gene contains an HBP1-binding site at position -426 to -433 bp from the transcriptional start site. HBP1 regulates the expression of the endogenous p16(INK4A) gene through direct sequence-specific binding. With HBP1 expression and the subsequent increase of p16(INK4A) gene expression, Ras induces premature senescence in primary cells. The data suggest a model in which Ras and p38 MAPK signaling engage HBP1 and p16(INK4A) to trigger premature senescence. In addition, we report that HBP1 knockdown is also required for Ras-induced transformation. All the data indicate that the mechanism of HBP1-mediated transcriptional regulation is important for not only premature senescence but also tumorigenesis.

  2. Hydrogen Treatment Protects against Cell Death and Senescence Induced by Oxidative Damage.

    Science.gov (United States)

    Han, A Lum; Park, Seong-Hoon; Park, Mi Sung

    2017-02-28

    Hydrogen has potential for preventive and therapeutic applications as an antioxidant. However, micro- and macroparticles of hydrogen in water disappear easily over time. In order to eliminate reactive oxygen species (ROS) related with the aging process, we used functional water containing nanoparticle hydrogen. Nanoparticle hydrogen does not disappear easily and collapse under water after long periods of time. We used murine embryonic fibroblasts that were isolated from 12.5-day embryos of C57BL/6 mice. We investigated the ability of nanoparticle hydrogen in water to suppress hydroxyurea-induced ROS production, cytotoxicity, and the accumulation of β-galactosidase (an indicator of aging), and promote cell proliferation. The accumulation of β-galactosidase in the cytoplasm and the appearance of abnormal nuclei were inhibited by daily treatment of cells with hydrogen water. When the aging process was accelerated by hydroxyurea-induced oxidative stress, the effect of hydrogen water was even more remarkable. Thus, this study showed the antioxidant and anti-senescence effects of hydrogen water. Nanoparticle hydrogen water is potentially a potent anti-aging agent.

  3. Isolation of the phagocytosis-inducing IgG-binding antigen on senescent somatic cells

    Science.gov (United States)

    Kay, Marguerite M. B.

    1981-02-01

    To remove senescent red blood cells (RBCs) from the circulation, macrophages must distinguish them from mature RBCs. That is achieved by a specific recognition system1,2. An antigen that develops on the surface of a senescing RBC is recognized and bound by the Fab region1 of an IgG autoantibody in the serum2. Subsequently the Fc region of the autoantibody is recognized and bound by a macrophage3, which proceeds to phagocytose the RBC. The antigenic molecule can be extracted from senescent but not young RBCs with Triton X-100 (ref. 4), although 10-30% as much antigen can be extracted from middle-aged as from senescent RBCs4. I have now used IgG autoantibodies eluted from senescent RBCs to isolate and purify the IgG-binding antigen on senescent RBCs, andto detect the antigen on other somatic cells. The antigen is a ~=62,000-Mr protein which is present on stored platelets, lymphocytes and neutrophils, and on cultured human adult liver and embryonic kidney cells, as well as senescent RBCs.

  4. Anti-Ageing Effects of Sonchus oleraceus L. (pūhā) Leaf Extracts on H2O2-Induced Cell Senescence

    OpenAIRE

    Zong-Quan Ou; Thomas Rades; Arlene McDowell

    2015-01-01

    Antioxidants protect against damage from free radicals and are believed to slow the ageing process. Previously, we have reported the high antioxidant activity of 70% methanolic Sonchus oleraceus L. (Asteraceae) leaf extracts. We hypothesize that S. oleraceus extracts protect cells against H2O2-induced senescence by mediating oxidative stress. Premature senescence of young WI-38 cells was induced by application of H2O2. Cells were treated with S. oleraceus extracts before or after H2O2 stress...

  5. Arabidopsis RabF1 (ARA6) Is Involved in Salt Stress and Dark-Induced Senescence (DIS)

    Science.gov (United States)

    Yin, Congfei; Karim, Sazzad; Zhang, Hongsheng; Aronsson, Henrik

    2017-01-01

    Arabidopsis small GTPase RabF1 (ARA6) functions in endosomal vesicle transport and may play a crucial role in recycling and degradation of molecules, thus involved in stress responses. Here we have reported that complementary overexpression lines RabF1OE (overexpression), GTPase mutants RabF1Q93L (constitutively active) and RabF1S47N (dominant negative) lines show longer root growth than wild-type, rabF1 knockout and N-myristoylation deletion (Δ1−29, N-terminus) complementary overexpression mutant plants under salt induced stress, which indicates that N-myristoylation of RabF1 is indispensable for salt tolerance. Moreover, RabF1 is highly expressed during senescence and RabF1OE lines were more tolerant of dark-induced senescence (DIS) than wild-type and rabF1. PMID:28157156

  6. The M-type receptor PLA2R regulates senescence through the p53 pathway.

    Science.gov (United States)

    Augert, Arnaud; Payré, Christine; de Launoit, Yvan; Gil, Jesus; Lambeau, Gérard; Bernard, David

    2009-03-01

    Senescence is a stable proliferative arrest induced by various stresses such as telomere erosion, oncogenic or oxidative stress. Compelling evidence suggests that it acts as a barrier against tumour development. Describing new mechanisms that favour an escape from senescence can thus reveal new insights into tumorigenesis. To identify new genes controlling the senescence programme, we performed a loss-of-function genetic screen in primary human fibroblasts. We report that knockdown of the M-type receptor PLA2R (phospholipase A2 receptor) prevents the onset of replicative senescence and diminishes stress-induced senescence. Interestingly, expression of PLA2R increases during replicative senescence, and its ectopic expression results in premature senescence. We show that PLA2R regulates senescence in a reactive oxygen species-DNA damage-p53-dependent manner. Taken together, our study identifies PLA2R as a potential new tumour suppressor gene crucial in the induction of cellular senescence through the activation of the p53 pathway.

  7. MiRNA profile associated with replicative senescence, extended cell culture, and ectopic telomerase expression in human foreskin fibroblasts.

    Directory of Open Access Journals (Sweden)

    Laura N Bonifacio

    Full Text Available Senescence is a highly regulated process that limits cellular replication by enforcing a G1 arrest in response to various stimuli. Replicative senescence occurs in response to telomeric DNA erosion, and telomerase expression can offset replicative senescence leading to immortalization of many human cells. Limited data exists regarding changes of microRNA (miRNA expression during senescence in human cells and no reports correlate telomerase expression with regulation of senescence-related miRNAs. We used miRNA microarrays to provide a detailed account of miRNA profiles for early passage and senescent human foreskin (BJ fibroblasts as well as early and late passage immortalized fibroblasts (BJ-hTERT that stably express the human telomerase reverse transcriptase subunit hTERT. Selected miRNAs that were differentially expressed in senescence were assayed for expression in quiescent cells to identify miRNAs that are specifically associated with senescence-associated growth arrest. From this group of senescence-associated miRNAs, we confirmed the ability of miR-143 to induce growth arrest after ectopic expression in young fibroblasts. Remarkably, miR-143 failed to induce growth arrest in BJ-hTERT cells. Importantly, the comparison of late passage immortalized fibroblasts to senescent wild type fibroblasts reveals that miR-146a, a miRNA with a validated role in regulating the senescence associated secretory pathway, is also regulated during extended cell culture independently of senescence. The discovery that miRNA expression is impacted by expression of ectopic hTERT as well as extended passaging in immortalized fibroblasts contributes to a comprehensive understanding of the connections between telomerase expression, senescence and processes of cellular aging.

  8. Drying without senescence in resurrection plants.

    Science.gov (United States)

    Griffiths, Cara A; Gaff, Donald F; Neale, Alan D

    2014-01-01

    Research into extreme drought tolerance in resurrection plants using species such as Craterostigma plantagineum, C. wilmsii, Xerophyta humilis, Tortula ruralis, and Sporobolus stapfianus has provided some insight into the desiccation tolerance mechanisms utilized by these plants to allow them to persist under extremely adverse environmental conditions. Some of the mechanisms used to ensure cellular preservation during severe dehydration appear to be peculiar to resurrection plants. Apart from the ability to preserve vital cellular components during drying and rehydration, such mechanisms include the ability to down-regulate growth-related metabolism rapidly in response to changes in water availability, and the ability to inhibit dehydration-induced senescence programs enabling reconstitution of photosynthetic capacity quickly following a rainfall event. Extensive research on the molecular mechanism of leaf senescence in non-resurrection plants has revealed a multi-layered regulatory network operates to control programed cell death pathways. However, very little is known about the molecular mechanisms that resurrection plants employ to avoid undergoing drought-related senescence during the desiccation process. To survive desiccation, dehydration in the perennial resurrection grass S. stapfianus must proceed slowly over a period of 7 days or more. Leaves detached from the plant before 60% relative water content (RWC) is attained are desiccation-sensitive indicating that desiccation tolerance is conferred in vegetative tissue of S. stapfianus when the leaf RWC has declined to 60%. Whilst some older leaves remaining attached to the plant during dehydration will senesce, suggesting dehydration-induced senescence may be influenced by leaf age or the rate of dehydration in individual leaves, the majority of leaves do not senesce. Rather these leaves dehydrate to air-dryness and revive fully following rehydration. Hence it seems likely that there are genes expressed in

  9. The microtubule stabilizing agent discodermolide is a potent inducer of accelerated cell senescence.

    Science.gov (United States)

    Klein, Laura E; Freeze, B Scott; Smith, Amos B; Horwitz, Susan Band

    2005-03-01

    Discodermolide is a microtubule stabilizing agent that suppresses dynamic instability and blocks cells in mitosis. Selection of A549 nonsmall cell lung carcinoma cells with increasing concentrations of discodermolide yielded a clone that proliferated in 8 nM. When these cells were exposed to any concentration greater than 8 nM, replication ceased and the cells developed a flattened, enlarged, granular morphology. Accelerated senescence was demonstrated by a functional beta-galactosidase activity at pH 6. When parental A549 cells were treated with IC50-concentrations of doxorubicin, Taxol or discodermolide, the latter two drugs quickly produced aberrant mitosis. However, discodermolide, but not Taxol, also produced a large increase in senescence-associated beta-galactosidase activity and altered levels of known senescence markers. Although some of these differences between Taxol and discodermolide were dose dependent, only discodermolide produced a doxorubicin-like induction of a senescence phenotype, including a senescence-associated beta-galactosidase activity, up-regulation of PAI-1 and p66Shc, and a strong, sustained, Erk1/2 activation. This research provides insights into the mechanism of action of discodermolide and provides the first demonstration of a microtubule stabilizing agent that inhibits tumor cell growth with a powerful induction of accelerated senescence.

  10. Senescence-inducible expression of isopentenyl transferase extends leaf life, increases drought stress resistance and alters cytokinin metabolism in cassava.

    Science.gov (United States)

    Zhang, Peng; Wang, Wen-Quan; Zhang, Gen-Liang; Kaminek, Miroslav; Dobrev, Petre; Xu, Jia; Gruissem, Wilhelm

    2010-07-01

    Cassava (Manihot esculenta Crantz) sheds its leaves during growth, especially within the tropical dry season. With the production of SAG12-IPT transgenic cassava we want to test the level of leaf retention and altered cytokinin metabolism of transgenic plants via the autoregulatory senescence inhibition system. After confirmation of transgene expression by molecular analysis and phenotype examination in greenhouse plants, two transgenic plant lines, 529-28 and 529-48, were chosen for further investigation. Detached mature leaves of 529-28 plants retained high levels of chlorophyll compared with wild-type leaves after dark-induced senescence treatment. Line 529-28 showed significant drought tolerance as indicated by stay-green capacity after drought stress treatment. Field experiments proved that leaf senescence syndrome was significantly delayed in 529-28 plants in comparison with wild-type and 529-48 plants. Physiological and agronomical characterizations of these plants also revealed that the induced expression of IPT had effects on photosynthesis, sugar allocation and nitrogen partitioning. Importantly, the 529-28 plants accumulated a high level of trans-zeatin-type cytokinins particularly of corresponding storage O-glucosides to maintain cytokinin homeostasis. Our study proves the feasibility of prolonging the leaf life of woody cassava and also sheds light on the control of cytokinin homeostasis in cassava leaves.

  11. Pseudolaric acid B-induced autophagy contributes to senescence via enhancement of ROS generation and mitochondrial dysfunction in murine fibrosarcoma L929 cells.

    Science.gov (United States)

    Qi, Min; Fan, Simiao; Yao, Guodong; Li, Zhao; Zhou, Haiyan; Tashiro, Shin-ichi; Onodera, Satoshi; Xia, Mingyu; Ikejima, Takashi

    2013-01-01

    Pseudolaric acid B (PAB) is the primary biologically active compound isolated from the root bark of P. kaempferi Gordon. Our previous study demonstrated that PAB induced mitotic catastrophe in L929 cells and indicated that only a small percentage (12%) of the cells undergoing mitotic catastrophe displayed an apoptotic phenotype after PAB treatment for 72 h. In this study, we found that a minority of the cells undergoing mitotic catastrophe ended in apoptosis, and a majority of them entered a period of senescence. Further data confirmed that PAB induced autophagy, reactive oxygen species (ROS) generation, and mitochondrial dysfunction in L929 cells. Subsequently, we found that autophagy inhibitors significantly delayed the senescence process, indicating that autophagy facilitated senescence. Moreover, ROS scavenger significantly decreased the autophagic level and improved mitochondrial function. Additionally, autophagy inhibitors effectively reduced ROS levels and ameliorated mitochondrial function. In conclusion, autophagy promoted senescence via enhancement of ROS generation and mitochondrial dysfunction in PAB-treated L929 cells.

  12. A potential role of flag leaf potassium in conferring tolerance to drought-induced leaf senescence in barley

    Directory of Open Access Journals (Sweden)

    Seyed A. Hosseini

    2016-02-01

    Full Text Available Terminal drought stress decreases crop yields by inducing abscisic acid (ABA and premature leaf senescence. As potassium (K is known to interfere with ABA homeostasis we addressed the question whether there is genetic variability regarding the role of K nutrition in ABA homeostasis and drought tolerance. To compare their response to drought stress, two barley lines contrasting in drought-induced leaf senescence were grown in a pot experiment under high and low K supply for the analysis of flag leaves from the same developmental stage. Relative to the drought-sensitive line LPR, the line HPR retained more K in its flag leaves under low K supply and showed delayed flag leaf senescence under terminal drought stress. High K retention was further associated with a higher leaf water status, a higher concentration of starch and other primary carbon metabolites. With regard to ABA homeostasis, HPR accumulated less ABA but higher levels of the ABA degradation products phaseic acid and dehydro-phaseic acid. Under K deficiency this went along with higher transcript levels of ABA8’-HYDROXYLASE, encoding a key enzyme in ABA degradation. The present study provides evidence for a positive impact of the K nutritional status on ABA homeostasis and carbohydrate metabolism under drought stress. We conclude that genotypes with a high K nutritional status in the flag leaf show superior drought tolerance by promoting ABA degradation but attenuating starch degradation which delays flag leaf senescence. Flag leaf K levels may thus represent a useful trait for the selection of drought-tolerant barley cultivars.

  13. TP53 disruptive mutations lead to head and neck cancer treatment failure through inhibition of radiation-induced senescence.

    Science.gov (United States)

    Skinner, Heath D; Sandulache, Vlad C; Ow, Thomas J; Meyn, Raymond E; Yordy, John S; Beadle, Beth M; Fitzgerald, Alison L; Giri, Uma; Ang, K Kian; Myers, Jeffrey N

    2012-01-01

    Mortality of patients with head and neck squamous cell carcinoma (HNSCC) is primarily driven by tumor cell radioresistance leading to locoregional recurrence (LRR). In this study, we use a classification of TP53 mutation (disruptive vs. nondisruptive) and examine impact on clinical outcomes and radiation sensitivity. Seventy-four patients with HNSCC treated with surgery and postoperative radiation and 38 HNSCC cell lines were assembled; for each, TP53 was sequenced and the in vitro radioresistance measured using clonogenic assays. p53 protein expression was inhibited using short hairpin RNA (shRNA) and overexpressed using a retrovirus. Radiation-induced apoptosis, mitotic cell death, senescence, and reactive oxygen species (ROS) assays were carried out. The effect of the drug metformin on overcoming mutant p53-associated radiation resistance was examined in vitro as well as in vivo, using an orthotopic xenograft model. Mutant TP53 alone was not predictive of LRR; however, disruptive TP53 mutation strongly predicted LRR (P = 0.03). Cell lines with disruptive mutations were significantly more radioresistant (P disruptive TP53 mutations significantly decreased radiation-induced senescence, as measured by SA-β-gal staining, p21 expression, and release of ROS. The mitochondrial agent metformin potentiated the effects of radiation in the presence of a disruptive TP53 mutation partially via senescence. Examination of our patient cohort showed that LRR was decreased in patients taking metformin. Disruptive TP53 mutations in HNSCC tumors predicts for LRR, because of increased radioresistance via the inhibition of senescence. Metformin can serve as a radiosensitizer for HNSCC with disruptive TP53, presaging the possibility of personalizing HNSCC treatment. © 2011 AACR.

  14. Global metabolic profiling of Arabidopsis Polyamine Oxidase 4 (AtPAO4 loss-of-function mutants exhibiting delayed dark-induced senescence

    Directory of Open Access Journals (Sweden)

    Miren Iranzu Sequera-Mutiozabal

    2016-02-01

    Full Text Available Early and more recent studies have suggested that some polyamines (PAs, and particularly spermine (Spm, exhibit anti-senescence properties in plants. In this work, we have investigated the role of Arabidopsis Polyamine Oxidase 4 (PAO4, encoding a PA back-conversion oxidase, during dark-induced senescence. Two independent PAO4 (pao4-1 and pao4-2 loss-of-function mutants have been found that accumulate 10-fold higher Spm, and this associated with delayed entry into senescence under dark conditions. Mechanisms underlying pao4 delayed senescence have been studied using global metabolic profiling by GC-TOF/MS. pao4 mutants exhibit constitutively higher levels of important metabolites involved in redox regulation, central metabolism and signaling that support a priming status against oxidative stress. During senescence, interactions between PAs and oxidative, sugar and nitrogen metabolism have been detected that additively contribute to delayed entry into senescence. Our results indicate the occurrence of metabolic interactions between PAs, particularly Spm, with cell oxidative balance and transport/biosynthesis of amino acids as a strategy to cope with oxidative damage produced during senescence.

  15. Identification of Senescent Cells in the Bone Microenvironment

    Science.gov (United States)

    Farr, Joshua N; Fraser, Daniel G; Wang, Haitao; Jaehn, Katharina; Ogrodnik, Mikolaj B; Weivoda, Megan M; Drake, Matthew T; Tchkonia, Tamara; LeBrasseur, Nathan K; Kirkland, James L; Bonewald, Lynda F; Pignolo, Robert J; Monroe, David G; Khosla, Sundeep

    2017-01-01

    Cellular senescence is a fundamental mechanism by which cells remain metabolically active yet cease dividing and undergo distinct phenotypic alterations, including upregulation of p16Ink4a, profound secretome changes, telomere shortening, and decondensation of pericentromeric satellite DNA. Because senescent cells accumulate in multiple tissues with aging, these cells and the dysfunctional factors they secrete, termed the senescence-associated secretory phenotype (SASP), are increasingly recognized as promising therapeutic targets to prevent age-related degenerative pathologies, including osteoporosis. However, the cell type(s) within the bone microenvironment that undergoes senescence with aging in vivo has remained poorly understood, largely because previous studies have focused on senescence in cultured cells. Thus in young (age 6 months) and old (age 24 months) mice, we measured senescence and SASP markers in vivo in highly enriched cell populations, all rapidly isolated from bone/marrow without in vitro culture. In both females and males, p16Ink4a expression by real-time quantitative polymerase chain reaction (rt-qPCR) was significantly higher with aging in B cells, T cells, myeloid cells, osteoblast progenitors, osteoblasts, and osteocytes. Further, in vivo quantification of senescence-associated distension of satellites (SADS), ie, large-scale unraveling of pericentromeric satellite DNA, revealed significantly more senescent osteocytes in old compared with young bone cortices (11% versus 2%, p < 0.001). In addition, primary osteocytes from old mice had sixfold more (p < 0.001) telomere dysfunction-induced foci (TIFs) than osteocytes from young mice. Corresponding with the age-associated accumulation of senescent osteocytes was significantly higher expression of multiple SASP markers in osteocytes from old versus young mice, several of which also showed dramatic age-associated upregulation in myeloid cells. These data show that with aging, a subset of cells

  16. Early leaf senescence is associated with an altered cellular redox balance in Arabidopsis cpr5/old1 mutants

    NARCIS (Netherlands)

    Jing, H. -C.; Hebeler, R.; Oeljeklaus, S.; Sitek, B.; Stuehler, K.; Meyer, H. E.; Sturre, M. J. G.; Hille, J.; Warscheid, B.; Dijkwel, P. P.; Stühler, K.

    2008-01-01

    Reactive oxygen species (ROS) are the inevitable by-products of essential cellular metabolic and physiological activities. Plants have developed sophisticated gene networks of ROS generation and scavenging systems. However, ROS regulation is still poorly understood. Here, we report that mutations in

  17. Early leaf senescence is associated with an altered cellular redox balance in Arabidopsis cpr5/old1 mutants

    NARCIS (Netherlands)

    Jing, H. -C.; Hebeler, R.; Oeljeklaus, S.; Sitek, B.; Stuehler, K.; Meyer, H. E.; Sturre, M. J. G.; Hille, J.; Warscheid, B.; Dijkwel, P. P.; Stühler, K.

    Reactive oxygen species (ROS) are the inevitable by-products of essential cellular metabolic and physiological activities. Plants have developed sophisticated gene networks of ROS generation and scavenging systems. However, ROS regulation is still poorly understood. Here, we report that mutations in

  18. Escherichia coli producing colibactin triggers premature and transmissible senescence in mammalian cells.

    Directory of Open Access Journals (Sweden)

    Thomas Secher

    Full Text Available Cellular senescence is an irreversible state of proliferation arrest evoked by a myriad of stresses including oncogene activation, telomere shortening/dysfunction and genotoxic insults. It has been associated with tumor activation, immune suppression and aging, owing to the secretion of proinflammatory mediators. The bacterial genotoxin colibactin, encoded by the pks genomic island is frequently harboured by Escherichia coli strains of the B2 phylogenetic group. Mammalian cells exposed to live pks+ bacteria exhibit DNA-double strand breaks (DSB and undergo cell-cycle arrest and death. Here we show that cells that survive the acute bacterial infection with pks+ E. coli display hallmarks of cellular senescence: chronic DSB, prolonged cell-cycle arrest, enhanced senescence-associated β-galactosidase (SA-β-Gal activity, expansion of promyelocytic leukemia nuclear foci and senescence-associated heterochromatin foci. This was accompanied by reactive oxygen species production and pro-inflammatory cytokines, chemokines and proteases secretion. These mediators were able to trigger DSB and enhanced SA-β-Gal activity in bystander recipient cells treated with conditioned medium from senescent cells. Furthermore, these senescent cells promoted the growth of human tumor cells. In conclusion, the present data demonstrated that the E. coli genotoxin colibactin induces cellular senescence and subsequently propel bystander genotoxic and oncogenic effects.

  19. SIRT1 ameliorates age-related senescence of mesenchymal stem cells via modulating telomere shelterin

    Directory of Open Access Journals (Sweden)

    Huiqiang eChen

    2014-06-01

    Full Text Available Age-related mesenchymal stem cells (MSCs senescence, which impairs its tissue repair capacity in vivo and hence compromises the effects of MSCs-based therapy in clinical applications, is closely related to aging and aging-related diseases. Here, we demonstrated the effect of SIRT1, a NAD+-dependent deacetylase, on age-related MSCs senescence. Knockdown of SIRT1 in young MSCs induces cellular senescence and inhibits cellular proliferation ability whereas overexpression of SIRT1 in aged MSCs reversed the cellular senescence and regained its proliferation capacity, suggesting that SIRT1 could modulate age-induced MSCs senescence. Aging-related proteins, P16 and P21, might be involved in SIRT1-mediated anti-aging effect on MSCs. SIRT1 could positively modulate age-related DNA damage in MSCs. In addition, SIRT1 could induce telomerase reverse transcriptase (TERT expression and consequently enhance telomerase activity, however, no significant change was observed in telomere length. Moreover, SIRT1 could positively regulate TPP1, an important member of telomere shelterin, expression. Together, these results demonstrate that SIRT1 dampens age-related MSCs senescence, which was correlated with the up-regulation of TPP1 expression, telomerase activity and down-regulation of DNA damage.

  20. Differential impact of lipoxygenase 2 and jasmonates on natural and stress-induced senescence in Arabidopsis.

    Science.gov (United States)

    Seltmann, Martin A; Stingl, Nadja E; Lautenschlaeger, Jens K; Krischke, Markus; Mueller, Martin J; Berger, Susanne

    2010-04-01

    Jasmonic acid and related oxylipins are controversially discussed to be involved in regulating the initiation and progression of leaf senescence. To this end, we analyzed profiles of free and esterified oxylipins during natural senescence and upon induction of senescence-like phenotypes by dark treatment and flotation on sorbitol in Arabidopsis (Arabidopsis thaliana). Jasmonic acid and free 12-oxo-phytodienoic acid increased during all three processes, with the strongest increase of jasmonic acid after dark treatment. Arabidopside content only increased considerably in response to sorbitol treatment. Monogalactosyldiacylglycerols and digalactosyldiacylglycerols decreased during these treatments and aging. Lipoxygenase 2-RNA interference (RNAi) plants were generated, which constitutively produce jasmonic acid and 12-oxo-phytodienoic acid but do not exhibit accumulation during natural senescence or upon stress treatment. Chlorophyll loss during aging and upon dark incubation was not altered, suggesting that these oxylipins are not involved in these processes. In contrast, lipoxygenase 2-RNAi lines and the allene oxid synthase-deficient mutant dde2 were less sensitive to sorbitol than the wild type, indicating that oxylipins contribute to the response to sorbitol stress.

  1. MicroRNA miR-125b induces senescence in human melanoma cells

    DEFF Research Database (Denmark)

    Glud, Martin; Manfé, Valentina; Biskup, Edyta

    2011-01-01

    in malignant melanoma producing lymph node micrometastases than in nonmetastasizing tumors. To get further insight into the functional role of miR-125b, we assessed whether its overexpression or silencing affects apoptosis, proliferation, or senescence in melanoma cell lines. We showed that overexpression...... in an early cutaneous malignant melanoma can contribute to the increased metastatic capability of this tumor....

  2. Oncogene-induced senescence is part of the tumorigenesis barrier imposed by DNA damage checkpoints

    DEFF Research Database (Denmark)

    Bartkova, Jirina; Rezaei, Nousin; Liontos, Michalis

    2006-01-01

    and DNA double-strand breaks. Inhibiting the DNA double-strand break response kinase ataxia telangiectasia mutated (ATM) suppressed the induction of senescence and in a mouse model led to increased tumour size and invasiveness. Analysis of human precancerous lesions further indicated that DNA damage...

  3. Knockdown of human deubiquitinase PSMD14 induces cell cycle arrest and senescence

    Energy Technology Data Exchange (ETDEWEB)

    Byrne, Ann; McLaren, Rajashree P.; Mason, Paul; Chai, Lilly; Dufault, Michael R.; Huang, Yinyin; Liang, Beirong; Gans, Joseph D.; Zhang, Mindy; Carter, Kara; Gladysheva, Tatiana B.; Teicher, Beverly A.; Biemann, Hans-Peter N.; Booker, Michael; Goldberg, Mark A.; Klinger, Katherine W.; Lillie, James [Genzyme Corporation, 49 New York Avenue, Framingham, MA 01701 (United States); Madden, Stephen L., E-mail: steve.madden@genzyme.com [Genzyme Corporation, 49 New York Avenue, Framingham, MA 01701 (United States); Jiang, Yide, E-mail: yide.jiang@genzyme.com [Genzyme Corporation, 49 New York Avenue, Framingham, MA 01701 (United States)

    2010-01-15

    The PSMD14 (POH1, also known as Rpn11/MPR1/S13/CepP1) protein within the 19S complex (19S cap; PA700) is responsible for substrate deubiquitination during proteasomal degradation. The role of PSMD14 in cell proliferation and senescence was explored using siRNA knockdown in carcinoma cell lines. Our results reveal that down-regulation of PSMD14 by siRNA transfection had a considerable impact on cell viability causing cell arrest in the G0-G1 phase, ultimately leading to senescence. The molecular events associated with decreased cell proliferation, cell cycle arrest and senescence include down-regulation of cyclin B1-CDK1-CDC25C, down-regulation of cyclin D1 and up-regulation of p21{sup /Cip} and p27{sup /Kip1}. Most notably, phosphorylation of the retinoblastoma protein was markedly reduced in PSMD14 knockdown cells. A comparative study with PSMB5, a subunit of the 20S proteasome, revealed that PSMB5 and PSMD14 have different effects on cell cycle, senescence and associated molecular events. These data support the view that the 19S and 20S subunits of the proteasome have distinct biological functions and imply that targeting 19S and 20S would have distinct molecular consequences on tumor cells.

  4. Nitric oxide prevents alveolar senescence and emphysema in a mouse model.

    Directory of Open Access Journals (Sweden)

    Amanda E Boe

    Full Text Available Nω-nitro-L-arginine methyl ester (L-NAME treatment induces arteriosclerosis and vascular senescence. Here, we report that the systemic inhibition of nitric oxide (NO production by L-NAME causes pulmonary emphysema. L-NAME-treated lungs exhibited both the structural (alveolar tissue destruction and functional (increased compliance and reduced elastance characteristics of emphysema development. Furthermore, we found that L-NAME-induced emphysema could be attenuated through both genetic deficiency and pharmacological inhibition of plasminogen activator inhibitor-1 (PAI-1. Because PAI-1 is an important contributor to the development of senescence both in vitro and in vivo, we investigated whether L-NAME-induced senescence led to the observed emphysematous changes. We found that L-NAME treatment was associated with molecular and cellular evidence of premature senescence in mice, and that PAI-1 inhibition attenuated these increases. These findings indicate that NO serves to protect and defend lung tissue from physiological aging.

  5. CHARACTERISTICS OF CELLULAR AND SERUM COMPONENTS OF MUCO-SALIVARY IMMUNE COMPARTMENT IN MATURE, AGED, AND SENESCENT PERSONS

    Directory of Open Access Journals (Sweden)

    E. D. Altman

    2011-01-01

    Full Text Available Аbstract. The objective of present study was to determine the immunological features of immune system aging in mucosa-associated lymphoid tissue (MALT in the patients at different ages (mature, aging and old observed at a dental unit. A study of cellular spectrum and humoral factors in salivary gland secretions has been performed in a group of 106 persons (35 to 90 years old. A number of age-dependent features of the immune profile were revealed for the mucous-salivary area, thus characterizing involution events within MALT structures. Among specific markers determining intensity of MALT-associated aging, a decreased percentage of viable immune cells (below 40%, along with the prevalence of the neutrophilic granulocytes in the salivary secretions (over 98% (with increased expression of β2-integrins; decreased counts of mononuclear cells, i.e., mononuclear cells with low expression of CD11β adhesion molecules, B-lymhocytes, and Th-lymphocytes have been revealed. Alterations in serum factors included a general decrease in complement system activity (СН50 and anaphylotoxines (С3а,С5а; elevated protein, mucine, and IgМ levels. The revealed specific features of cellular and humoral immunity within MALT-associated muco-salivary zone may be considered as a normal response connected with natural aging processes. (Med. Immunol., 2011, vol. 13, N 2-3, pp 167-174

  6. Chronic Low Dose Rate Ionizing Radiation Exposure Induces Premature Senescence in Human Fibroblasts that Correlates with Up Regulation of Proteins Involved in Protection against Oxidative Stress

    Directory of Open Access Journals (Sweden)

    Olga Loseva

    2014-07-01

    Full Text Available The risks of non-cancerous diseases associated with exposure to low doses of radiation are at present not validated by epidemiological data, and pose a great challenge to the scientific community of radiation protection research. Here, we show that premature senescence is induced in human fibroblasts when exposed to chronic low dose rate (LDR exposure (5 or 15 mGy/h of gamma rays from a 137Cs source. Using a proteomic approach we determined differentially expressed proteins in cells after chronic LDR radiation compared to control cells. We identified numerous proteins involved in protection against oxidative stress, suggesting that these pathways protect against premature senescence. In order to further study the role of oxidative stress for radiation induced premature senescence, we also used human fibroblasts, isolated from a patient with a congenital deficiency in glutathione synthetase (GS. We found that these GS deficient cells entered premature senescence after a significantly shorter time of chronic LDR exposure as compared to the GS proficient cells. In conclusion, we show that chronic LDR exposure induces premature senescence in human fibroblasts, and propose that a stress induced increase in reactive oxygen species (ROS is mechanistically involved.

  7. ATM-deficient human fibroblast cells are resistant to low levels of DNA double-strand break induced apoptosis and subsequently undergo drug-induced premature senescence

    Energy Technology Data Exchange (ETDEWEB)

    Park, Jun; Jo, Yong Hwa; Cho, Chang Hoon; Choe, Wonchae; Kang, Insug; Baik, Hyung Hwan [Department of Biochemistry and Molecular Biology, School of Medicine, Kyung Hee University, 26 Kyunghee-daero, Dongdaemun-gu, Seoul 130-701 (Korea, Republic of); Yoon, Kyung-Sik, E-mail: sky9999@khu.ac.kr [Department of Biochemistry and Molecular Biology, School of Medicine, Kyung Hee University, 26 Kyunghee-daero, Dongdaemun-gu, Seoul 130-701 (Korea, Republic of)

    2013-01-04

    Highlights: Black-Right-Pointing-Pointer A-T cells were not hypersensitive to low levels of DNA DSBs. Black-Right-Pointing-Pointer A-T cells have enhanced Akt but defect in activation of p53 and apoptotic proteins. Black-Right-Pointing-Pointer A-T cells underwent premature senescence after DNA damage accumulated. Black-Right-Pointing-Pointer Chemotherapeutic effect in cancer therapy may be associated with premature senescence. -- Abstract: DNA DSBs are induced by IR or radiomimetic drugs such as doxorubicin. It has been indicated that cells from ataxia-telangiectasia patients are highly sensitive to radiation due to defects in DNA repair, but whether they have impairment in apoptosis has not been fully elucidated. A-T cells showed increased sensitivity to high levels of DNA damage, however, they were more resistant to low doses. Normal cells treated with combination of KU55933, a specific ATM kinase inhibitor, and doxorubicin showed increased resistance as they do in a similar manner to A-T cells. A-T cells have higher viability but more DNA breaks, in addition, the activations of p53 and apoptotic proteins (Bax and caspase-3) were deficient, but Akt expression was enhanced. A-T cells subsequently underwent premature senescence after treatment with a low dose of doxorubicin, which was confirmed by G2 accumulation, senescent morphology, and SA-{beta}-gal positive until 15 days repair incubation. Finally, A-T cells are radio-resistant at low doses due to its defectiveness in detecting DNA damage and apoptosis, but the accumulation of DNA damage leads cells to premature senescence.

  8. MicroRNA-34a Induces Vascular Smooth Muscle Cells Senescence by SIRT1 Downregulation and Promotes the Expression of Age-Associated Pro-inflammatory Secretory Factors.

    Science.gov (United States)

    Badi, Ileana; Burba, Ilaria; Ruggeri, Clarissa; Zeni, Filippo; Bertolotti, Matteo; Scopece, Alessandro; Pompilio, Giulio; Raucci, Angela

    2015-11-01

    Arterial aging is a major risk factor for the occurrence of cardiovascular diseases. The aged artery is characterized by endothelial dysfunction and vascular smooth muscle cells altered physiology together with low-grade chronic inflammation. MicroRNA-34a (miR-34a) has been recently implicated in cardiac, endothelial, and endothelial progenitor cell senescence; however, its contribution to aging-associated vascular smooth muscle cells phenotype has not been explored so far. We found that miR-34a was highly expressed in aortas isolated from old mice. Moreover, its well-known target, the longevity-associated protein SIRT1, was significantly downregulated during aging in both endothelial cells and vascular smooth muscle cells. Increased miR-34a as well as decreased SIRT1 expression was also observed in replicative-senescent human aortic smooth muscle cells. miR-34a overexpression in proliferative human aortic smooth muscle cells caused cell cycle arrest along with enhanced p21 protein levels and evidence of cell senescence. Furthermore, miR-34a ectopic expression induced pro-inflammatory senescence-associated secretory phenotype molecules. Finally, SIRT1 protein significantly decreased upon miR-34a overexpression and restoration of its levels rescued miR-34a-dependent human aortic smooth muscle cells senescence, but not senescence-associated secretory phenotype factors upregulation. Taken together, our findings suggest that aging-associated increase of miR-34a expression levels, by promoting vascular smooth muscle cells senescence and inflammation through SIRT1 downregulation and senescence-associated secretory phenotype factors induction, respectively, may lead to arterial dysfunctions.

  9. p16(INK4A) induces senescence and inhibits EMT through microRNA-141/microRNA-146b-5p-dependent repression of AUF1.

    Science.gov (United States)

    Al-Khalaf, Huda H; Aboussekhra, Abdelilah

    2017-03-01

    Senescence and epithelial-to-mesenchymal transition (EMT) processes are under the control of common tumor suppressor proteins, EMT transcription factors, and microRNAs. However, the molecular mechanisms that coordinate the functional link between senescence and EMT are still elusive. We have shown here that p16(INK4A) -related induction of senescence is mediated through miR-141 and miR-146b-5p. These two microRNAs are up-regulated in aging human fibroblast and epithelial cells. Furthermore, miR-141 and miR146b-5p trigger cell cycle arrest at G1 phase and induce senescence in primary human fibroblasts and breast cancer cells in the presence and absence of p16(INK4A) . Like p16(INK4A) -induced senescence, miR-141/miR146b-5p-related senescence is not associated with secretory phenotype, and is mediated through the RNA binding protein AUF1. We have further demonstrated that p16(INK4A) and its downstream miRNA targets inhibit EMT through suppressing the EMT inducer ZEB1 in an AUF1-dependent manner. Indeed, AUF1 binds the mRNA of this gene leading to increase in its level. These results indicate that p16(INK4A) controls both senescence and EMT through repressing EMT-related transcription factor via miR-141/miR146b-5p and their target AUF1. This sheds more light on the molecular basis of the tumor suppressive functions of p16(INK4A) , which represses both the proliferative and the migratory/invasive capacities of cells. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

  10. p53-dependent release of Alarmin HMGB1 is a central mediator of senescent phenotypes.

    Science.gov (United States)

    Davalos, Albert R; Kawahara, Misako; Malhotra, Gautam K; Schaum, Nicholas; Huang, Jiahao; Ved, Urvi; Beausejour, Christian M; Coppe, Jean-Philippe; Rodier, Francis; Campisi, Judith

    2013-05-13

    Cellular senescence irreversibly arrests proliferation in response to potentially oncogenic stress. Senescent cells also secrete inflammatory cytokines such as IL-6, which promote age-associated inflammation and pathology. HMGB1 (high mobility group box 1) modulates gene expression in the nucleus, but certain immune cells secrete HMGB1 as an extracellular Alarmin to signal tissue damage. We show that nuclear HMGB1 relocalized to the extracellular milieu in senescent human and mouse cells in culture and in vivo. In contrast to cytokine secretion, HMGB1 redistribution required the p53 tumor suppressor, but not its activator ATM. Moreover, altered HMGB1 expression induced a p53-dependent senescent growth arrest. Senescent fibroblasts secreted oxidized HMGB1, which stimulated cytokine secretion through TLR-4 signaling. HMGB1 depletion, HMGB1 blocking antibody, or TLR-4 inhibition attenuated senescence-associated IL-6 secretion, and exogenous HMGB1 stimulated NF-κB activity and restored IL-6 secretion to HMGB1-depleted cells. Our findings identify senescence as a novel biological setting in which HMGB1 functions and link HMGB1 redistribution to p53 activity and senescence-associated inflammation.

  11. Long noncoding RNA PANDA and scaffold-attachment-factor SAFA control senescence entry and exit.

    Science.gov (United States)

    Puvvula, Pavan Kumar; Desetty, Rohini Devi; Pineau, Pascal; Marchio, Agnés; Moon, Anne; Dejean, Anne; Bischof, Oliver

    2014-11-19

    Cellular senescence is a stable cell cycle arrest that limits the proliferation of pre-cancerous cells. Here we demonstrate that scaffold-attachment-factor A (SAFA) and the long noncoding RNA PANDA differentially interact with polycomb repressive complexes (PRC1 and PRC2) and the transcription factor NF-YA to either promote or suppress senescence. In proliferating cells, SAFA and PANDA recruit PRC complexes to repress the transcription of senescence-promoting genes. Conversely, the loss of SAFA-PANDA-PRC interactions allows expression of the senescence programme. Accordingly, we find that depleting either SAFA or PANDA in proliferating cells induces senescence. However, in senescent cells where PANDA sequesters transcription factor NF-YA and limits the expression of NF-YA-E2F-coregulated proliferation-promoting genes, PANDA depletion leads to an exit from senescence. Together, our results demonstrate that PANDA confines cells to their existing proliferative state and that modulating its level of expression can cause entry or exit from senescence.

  12. p53-dependent release of Alarmin HMGB1 is a central mediator of senescent phenotypes

    Science.gov (United States)

    Kawahara, Misako; Malhotra, Gautam K.; Schaum, Nicholas; Huang, Jiahao; Ved, Urvi; Beausejour, Christian M.; Coppe, Jean-Philippe; Rodier, Francis

    2013-01-01

    Cellular senescence irreversibly arrests proliferation in response to potentially oncogenic stress. Senescent cells also secrete inflammatory cytokines such as IL-6, which promote age-associated inflammation and pathology. HMGB1 (high mobility group box 1) modulates gene expression in the nucleus, but certain immune cells secrete HMGB1 as an extracellular Alarmin to signal tissue damage. We show that nuclear HMGB1 relocalized to the extracellular milieu in senescent human and mouse cells in culture and in vivo. In contrast to cytokine secretion, HMGB1 redistribution required the p53 tumor suppressor, but not its activator ATM. Moreover, altered HMGB1 expression induced a p53-dependent senescent growth arrest. Senescent fibroblasts secreted oxidized HMGB1, which stimulated cytokine secretion through TLR-4 signaling. HMGB1 depletion, HMGB1 blocking antibody, or TLR-4 inhibition attenuated senescence-associated IL-6 secretion, and exogenous HMGB1 stimulated NF-κB activity and restored IL-6 secretion to HMGB1-depleted cells. Our findings identify senescence as a novel biological setting in which HMGB1 functions and link HMGB1 redistribution to p53 activity and senescence-associated inflammation. PMID:23649808

  13. Argentatin B Inhibits Proliferation of Prostate and Colon Cancer Cells by Inducing Cell Senescence

    OpenAIRE

    Ela Alcántara-Flores; Alicia Enriqueta Brechú-Franco; Patricia García-López; Leticia Rocha-Zavaleta; Rebeca López-Marure; Mariano Martínez-Vázquez

    2015-01-01

    Argentatin B has been shown to inhibit the growth of colon HCT-15, and prostate PC-3 cancer cells. However, the mechanism by which argentatin B inhibits cell proliferation is still unknown. We aimed to investigate the mechanism by which argentatin B inhibits cell proliferation. The cell cycle was studied by flow cytometry. Apoptosis was evaluated by Annexin-V-Fluos, and Hoechst 33342 dye staining. Cell senescence was evaluated by proliferation tests, and staining for SA-β-galactosidase. Senes...

  14. The profile of lysosomal exoglycosidases in replicative and stress-induced senescence in early passage human fibroblasts

    Directory of Open Access Journals (Sweden)

    Małgorzata Knaś

    2012-07-01

    Full Text Available The aim of the present study was to assess the profiles of the exoglycosidases: N-acetyl-β-hexosoaminidase, β glucuronidase and β galactosidase, α mannosidase and α fucosidase in fibroblast culture undergoing replicative and stress-induced senescence. Half of the cell culture was grown in normal conditions, without the stressor, and the other half of the cell was treated with 0.15 mM tert-butylhydroperoxide. The activities of total N-acetyl-β-hexosoaminidase as well as β glucuronidase in the cell lysate were determined in duplicates using the method of Marciniak et al. The activities of β galactosidase, α mannosidase and α fucosidase in the cell lysate were determined in duplicates using the method of Chatteriee et al. with the modification by Zwierz et al. The activities of the exoglycosidases examined, with the exception of β glucuronidase, showed a significant increase between individual days of the experiment in both non-stressed and stressed fibroblast cell culture. On each day of the experiment, in the cell lysate of stressed fibroblasts, the activities of exoglycosidases were significantly higher compared to the non-stressed cells. There were very strong correlations between SA-β-GAL staining and b galactosidase activity on individual days of the experiment in both non-stressed and stressed fibroblast cell culture. Replicative and stress-induced senescence results in significant changes to the level of lysosomal exoglycosidases, and results in enhanced lysosomal degradative capacity.

  15. Stable SREBP-1a knockdown decreases the cell proliferation rate in human preadipocyte cells without inducing senescence

    Energy Technology Data Exchange (ETDEWEB)

    Alvarez, María Soledad [Instituto de Biomedicina de Valencia (IBV-CSIC), Jaime Roig 11, E-46010 Valencia (Spain); Fernandez-Alvarez, Ana [Fundación Instituto Leloir, IIBBA-CONICET, Av. Patricias Argentinas 435, Ciudad Autónoma de Buenos Aires C1405BWE (Argentina); Cucarella, Carme [Instituto de Biomedicina de Valencia (IBV-CSIC), Jaime Roig 11, E-46010 Valencia (Spain); Casado, Marta, E-mail: mcasado@ibv.csic.es [Instituto de Biomedicina de Valencia (IBV-CSIC), Jaime Roig 11, E-46010 Valencia (Spain)

    2014-04-25

    Highlights: • SGBS cells mostly expressed SREBP-1a variant. • SREBP-1a knockdown decreased the proliferation of SGBS cells without inducing senescence. • We have identified RBBP8 and CDKN3 genes as potential SREBP-1a targets. - Abstract: Sterol regulatory element binding proteins (SREBP), encoded by the Srebf1 and Srebf2 genes, are important regulators of genes involved in cholesterol and fatty acid metabolism. Whereas SREBP-2 controls the cholesterol synthesis, SREBP-1 proteins (-1a and -1c) function as the central hubs in lipid metabolism. Despite the key function of these transcription factors to promote adipocyte differentiation, the roles of SREBP-1 proteins during the preadipocyte state remain unknown. Here, we evaluate the role of SREBP-1 in preadipocyte proliferation using RNA interference technology. Knockdown of the SREBP-1a gene decreased the proliferation rate in human SGBS preadipocyte cell strain without inducing senescence. Furthermore, our data identified retinoblastoma binding protein 8 and cyclin-dependent kinase inhibitor 3 genes as new potential SREBP-1 targets, in addition to cyclin-dependent kinase inhibitor 1A which had already been described as a gene regulated by SREBP-1a. These data suggested a new role of SREBP-1 in adipogenesis via regulation of preadipocyte proliferation.

  16. Bclaf1 is an important NF-κB signaling transducer and C/EBPβ regulator in DNA damage-induced senescence.

    Science.gov (United States)

    Shao, A-w; Sun, H; Geng, Y; Peng, Q; Wang, P; Chen, J; Xiong, T; Cao, R; Tang, J

    2016-05-01

    Inducing senescence in cancer cells is an effective approach to suppress cancer growth, and it contributes significantly to the efficacy of therapeutic drugs. Previous studies indicated that transcription factors NF-κB (nuclear factor κ-light-chain-enhancer of activated B cells) and C/EBPβ (CCAAT/enhancer-binding protein-β) play a critical role in the establishment of senescence by upregulating proinflammatory cytokines, notably interleukin-6 (IL-6) and interleukin-8 (IL-8). However, it is not clear how these two factors are activated in response to senescence-inducing stimuli and subsequently regulate gene transcription. Here, we reveal Bcl-2-associated transcription factor 1 (Bclaf1) as a novel player in the therapeutic drug doxorubicin-induced senescence (TIS) in multiple cancer cells. Bclaf1 is upregulated through the ATM/Nemo/NF-κB pathway during TIS and is a direct target of p65 and c-Rel. The induction of Bclaf1 by NF-κB is essential for C/EBPβ upregulation and IL-6/IL-8 transcription during TIS. Bclaf1 can interact with the leucine zipper region of C/EBPβ and cooperate with C/EBPβ to upregulate IL-8. Furthermore, we show that Bclaf1 is required for the effectiveness of doxorubicin (Dox) treatment-induced tumor suppression in a xenograft tumor model. These finding suggest that Bclaf1 plays a crucial role in transducing the senescence-inducing signal from NF-κB to C/EBPβ during TIS, thus amplifying the signals for the establishment of senescence. Given the recent revelation that Bclaf1 is involved in tumorigenesis, our data indicate that the responsiveness of Bclaf1 to NF-κB may determine the effectiveness of therapeutic drugs.

  17. Induced static magnetic field by a cellular phone

    Science.gov (United States)

    Einat, M.; Yahalom, A.

    2011-08-01

    Recent claims regarding the safety of cellular phones suggest that weak static magnetic fields are induced around the phone, and this field and its gradients may pose a health risk to the user. An experiment was conducted to measure the induced static magnetic field around a cellular phone. 65 μT variations and 18 μT/cm gradients were measured in the magnetic field at 6 cm from the phone. An analytical model is derived to explain the results. The influence that the measured magnetic fields may have on the user is beyond the scope of this research.

  18. Notch Activation Induces Endothelial Cell Senescence and Pro-inflammatory Response: Implication of Notch Signaling in Atherosclerosis

    Science.gov (United States)

    Liu, Zhao-Jun; Tan, Yurong; Beecham, Gary W.; Seo, David M.; Tian, Runxia; Li, Yan; Vazquez-Padron, Roberto I.; Pericak-Vance, Margaret; Vance, Jeffery M.; Goldschmidt-Clermont, Pascal J.; Livingstone, Alan S.; Velazquez, Omaida C.

    2012-01-01

    Objective Notch signaling plays pivotal roles in the pathogenesis of vascular disease. However, little is known about its role in atherosclerosis. We sought to investigate the potential involvement of the Notch signaling in atherosclerosis. Methods Expression of Notch pathway components in mouse and human aorta with or without atherosclerosis plaque was examined by immuno-histochemistry. Expression of Notch target genes in young versus aged human endothelial cells (EC) was examined by PCRArray and immunoblot. In vitro loss- and gain-of-function approaches were utilized to evaluate the role of Notch signaling in inducing EC senescence and secretion of pro-inflammatory cytokines by ProteinArray. Notch gene profile was studied in 1054 blood samples of patients with coronary artery disease (CAD). Genotyping was performed using the Genome-Wide Single Nucleotide Polymorphism (SNP) Array. Results Notch pathway components were upregulated in luminal EC at atherosclerotic lesions from mouse and human aortas. In addition, the Notch pathway was activated in aged but not young human EC. Enforced Notch activation resulted in EC senescence and significantly upregulated expression of several molecules implicated in the inflammatory response (IL-6/IL-8/IL-1α/RANTES/ICAM-1). The upregulated IL-6 was partially responsible for mediating leukocyte transendothelial migration. Genetic association analysis detected, of 82 SNPs across 6 Notch pathway genes analyzed, 4 SNPs with nominal association with CAD burden. Conclusion Notch pathway is activated in luminal EC at atherosclerotic plaques and results in pro-inflammatory response and senescence of EC. Notch signaling may be linked to human CAD risk. These findings implicate a potential involvement of Notch signaling in atherosclerosis. PMID:23078884

  19. miR-125b induces cellular senescence in malignant melanoma

    DEFF Research Database (Denmark)

    Nyholm, Anne Marie; Lerche, Catharina M; Manfé, Valentina

    2014-01-01

    of lymph node metastasis in cutaneous malignant melanoma. Our goal was therefore to further examine this theory. METHODS: We used in-situ-hybridization to visualise miR-125b expression in primary tumours and in lymph node metastasis. Then using a miRVector plasmid containing a miR-125b-1 insert we...... transfected melanoma cell line Mel-Juso and then investigated the effect of the presence of a stable overexpression of miR-125b on growth by western blotting, flow cytometry and β-galactosidase staining. The tumourogenicity of the transfected cells was tested using a murine model and the tumours were further...... examined with in-situ-hybridization. RESULTS: In primary human tumours and in lymph node metastases increased expression of miR-125b was found in single, large tumour cells with abundant cytoplasm. A stable overexpression of miR-125b in human melanoma cell line Mel-Juso resulted in a G0/G1 cell cycle block...

  20. miR-125b induces cellular senescence in malignant melanoma

    DEFF Research Database (Denmark)

    Nyholm, Anne Marie; Lerche, Catharina M; Manfé, Valentina;

    2014-01-01

    BACKGROUND: Micro RNAs (miRs) have emerged as key regulators during oncogenesis. They have been found to regulate cell proliferation, differentiation, and apoptosis. Mir-125b has been identified as an oncomir in various forms of tumours, but we have previously proposed that miR-125b is a suppressor...... of lymph node metastasis in cutaneous malignant melanoma. Our goal was therefore to further examine this theory. METHODS: We used in-situ-hybridization to visualise miR-125b expression in primary tumours and in lymph node metastasis. Then using a miRVector plasmid containing a miR-125b-1 insert we...... transfected melanoma cell line Mel-Juso and then investigated the effect of the presence of a stable overexpression of miR-125b on growth by western blotting, flow cytometry and β-galactosidase staining. The tumourogenicity of the transfected cells was tested using a murine model and the tumours were further...

  1. Cellular senescence and autophagy of myoepithelial cells are involved in the progression of in situ areas of carcinoma ex-pleomorphic adenoma to invasive carcinoma. An in vitro model.

    Science.gov (United States)

    Silva, Carolina Amália Barcellos; Martinez, Elizabeth Ferreira; Demasi, Ana Paula Dias; Altemani, Albina; da Silveira Bossonaro, Jeruza Pinheiro; Araújo, Ney Soares; de Araújo, Vera Cavalcanti

    2015-09-01

    During tumor invasion, benign myoepithelial cells of carcinoma ex-pleomorphic adenoma (CXPA) surround malignant epithelial cells and disappear. The mechanisms involved in the death and disappearance of these myoepithelial cells were investigated via analysis of the expression of regulatory proteins for apoptosis, autophagy and cellular senescence in an in situ in vitro model. Protein expression relating to apoptosis (Bax, Bcl-2, Survivin), autophagy (Beclin-1, LC3B) and cellular senescence (p21, p16) was evaluated using indirect immunofluorescence. β-galactosidase expression was assessed via histochemistry. Biopsies of CXPA (ex vivo) allowed immunhistochemical evaluation of p21 and p16, whilst LC3B, p21 and p16 protein expression was analyzed by western blotting. In the in vitro model, the myoepithelial cells were positive for LC3B (cytoplasm) and p21 (nucleus), whilst in vivo positivity for p21 and p16 was observed. In vitro, β-galactosidase activity increased in the myoepithelial cells over time. Western blotting analysis revealed an increased LC3B, p16 and p21 expression in the myoepithelial cells with previous contact with the malignant cells when compared with those without contact. The investigation of behavior of benign myoepithelial cells in ductal areas of CXAP revealed that the myoepithelial cells are involved in the autophagy-senescence phenotype that subsequently leads to their disappearance.

  2. Combinatorial approaches to evaluate nanodiamond uptake and induced cellular fate.

    Science.gov (United States)

    Eldawud, Reem; Reitzig, Manuela; Opitz, Jörg; Rojansakul, Yon; Jiang, Wenjuan; Nangia, Shikha; Dinu, Cerasela Zoica

    2016-02-26

    Nanodiamonds (NDs) are an emerging class of engineered nanomaterials that hold great promise for the next generation of bionanotechnological products to be used for drug and gene delivery, or for bio-imaging and biosensing. Previous studies have shown that upon their cellular uptake, NDs exhibit high biocompatibility in various in vitro and in vivo set-ups. Herein we hypothesized that the increased NDs biocompatibility is a result of minimum membrane perturbations and their reduced ability to induce disruption or damage during cellular translocation. Using multi-scale combinatorial approaches that simulate ND-membrane interactions, we correlated NDs real-time cellular uptake and kinetics with the ND-induced membrane fluctuations to derive energy requirements for the uptake to occur. Our discrete and real-time analyses showed that the majority of NDs internalization occurs within 2 h of cellular exposure, however, with no effects on cellular viability, proliferation or cellular behavior. Furthermore, our simulation analyses using coarse-grained models identified key changes in the energy profile, membrane deformation and recovery time, all functions of the average ND or ND-based agglomerate size. Understanding the mechanisms responsible for ND-cell membrane interactions could possibly advance their implementation in various biomedical applications.

  3. Combinatorial approaches to evaluate nanodiamond uptake and induced cellular fate

    Science.gov (United States)

    Eldawud, Reem; Reitzig, Manuela; Opitz, Jörg; Rojansakul, Yon; Jiang, Wenjuan; Nangia, Shikha; Zoica Dinu, Cerasela

    2016-02-01

    Nanodiamonds (NDs) are an emerging class of engineered nanomaterials that hold great promise for the next generation of bionanotechnological products to be used for drug and gene delivery, or for bio-imaging and biosensing. Previous studies have shown that upon their cellular uptake, NDs exhibit high biocompatibility in various in vitro and in vivo set-ups. Herein we hypothesized that the increased NDs biocompatibility is a result of minimum membrane perturbations and their reduced ability to induce disruption or damage during cellular translocation. Using multi-scale combinatorial approaches that simulate ND-membrane interactions, we correlated NDs real-time cellular uptake and kinetics with the ND-induced membrane fluctuations to derive energy requirements for the uptake to occur. Our discrete and real-time analyses showed that the majority of NDs internalization occurs within 2 h of cellular exposure, however, with no effects on cellular viability, proliferation or cellular behavior. Furthermore, our simulation analyses using coarse-grained models identified key changes in the energy profile, membrane deformation and recovery time, all functions of the average ND or ND-based agglomerate size. Understanding the mechanisms responsible for ND-cell membrane interactions could possibly advance their implementation in various biomedical applications.

  4. MicroRNAs Regulate Key Effector Pathways of Senescence

    Directory of Open Access Journals (Sweden)

    Andrea Feliciano

    2011-01-01

    Full Text Available MicroRNAs (miRNAs are small (approximately 22 nt noncoding endogenous RNA molecules that regulate gene expression and protein coding by base pairing with the 3′ untranslated region (UTR of target mRNAs. miRNA expression is associated with cancer pathogenesis because miRNAs are intimately linked to cancer development. Senescence blocks cell proliferation, representing an important barrier that cells must bypass to reach malignancy. Importantly, certain miRNAs have been shown to have an important role during cellular senescence, which is also involved in human tumorigenesis. Therefore, therapeutic induction of senescence by drugs or miRNA-based therapies is a potential method to treat cancer by inducing a persistent growth arrest in tumors.

  5. Epithelial cell senescence impairs repair process and exacerbates inflammation after airway injury

    Directory of Open Access Journals (Sweden)

    Nagai Atsushi

    2011-06-01

    Full Text Available Abstract Background Genotoxic stress, such as by exposure to bromodeoxyuridine (BrdU and cigarette smoke, induces premature cell senescence. Recent evidence indicates that cellular senescence of various types of cells is accelerated in COPD patients. However, whether the senescence of airway epithelial cells contributes to the development of airway diseases is unknown. The present study was designed to test the hypothesis that premature senescence of airway epithelial cells (Clara cells impairs repair processes and exacerbates inflammation after airway injury. Methods C57/BL6J mice were injected with the Clara-cell-specific toxicant naphthalene (NA on days 0, 7, and 14, and each NA injection was followed by a daily dose of BrdU on each of the following 3 days, during which regenerating cells were allowed to incorporate BrdU into their DNA and to senesce. The p38 MAPK inhibitor SB202190 was injected 30 minutes before each BrdU dose. Mice were sacrificed at different times until day 28 and lungs of mice were obtained to investigate whether Clara cell senescence impairs airway epithelial regeneration and exacerbates airway inflammation. NCI-H441 cells were induced to senesce by exposure to BrdU or the telomerase inhibitor MST-312. Human lung tissue samples were obtained from COPD patients, asymptomatic smokers, and nonsmokers to investigate whether Clara cell senescence is accelerated in the airways of COPD patients, and if so, whether it is accompanied by p38 MAPK activation. Results BrdU did not alter the intensity of the airway epithelial injury or inflammation after a single NA exposure. However, after repeated NA exposure, BrdU induced epithelial cell (Clara cell senescence, as demonstrated by a DNA damage response, p21 overexpression, increased senescence-associated β-galactosidase activity, and growth arrest, which resulted in impaired epithelial regeneration. The epithelial senescence was accompanied by p38 MAPK-dependent airway

  6. The SETD8/PR-Set7 Methyltransferase Functions as a Barrier to Prevent Senescence-Associated Metabolic Remodeling

    Directory of Open Access Journals (Sweden)

    Hiroshi Tanaka

    2017-02-01

    Full Text Available Cellular senescence is an irreversible growth arrest that contributes to development, tumor suppression, and age-related conditions. Senescent cells show active metabolism compared with proliferating cells, but the underlying mechanisms remain unclear. Here we show that the SETD8/PR-Set7 methyltransferase, which catalyzes mono-methylation of histone H4 at lysine 20 (H4K20me1, suppresses nucleolar and mitochondrial activities to prevent cellular senescence. SETD8 protein was selectively downregulated in both oncogene-induced and replicative senescence. Inhibition of SETD8 alone was sufficient to trigger senescence. Under these states, the expression of genes encoding ribosomal proteins (RPs and ribosomal RNAs as well as the cyclin-dependent kinase (CDK inhibitor p16INK4A was increased, with a corresponding reduction of H4K20me1 at each locus. As a result, the loss of SETD8 concurrently stimulated nucleolar function and retinoblastoma protein-mediated mitochondrial metabolism. In conclusion, our data demonstrate that SETD8 acts as a barrier to prevent cellular senescence through chromatin-mediated regulation of senescence-associated metabolic remodeling.

  7. Ectopic expression of Capsicum-specific cell wall protein Capsicum annuum senescence-delaying 1 (CaSD1) delays senescence and induces trichome formation in Nicotiana benthamiana.

    Science.gov (United States)

    Seo, Eunyoung; Yeom, Seon-In; Jo, Sunghwan; Jeong, Heejin; Kang, Byoung-Cheorl; Choi, Doil

    2012-04-01

    Secreted proteins are known to have multiple roles in plant development, metabolism, and stress response. In a previous study to understand the roles of secreted proteins, Capsicum annuum secreted proteins (CaS) were isolated by yeast secretion trap. Among the secreted proteins, we further characterized Capsicum annuum senescence-delaying 1 (CaSD1), a gene encoding a novel secreted protein that is present only in the genus Capsicum. The deduced CaSD1 contains multiple repeats of the amino acid sequence KPPIHNHKPTDYDRS. Interestingly, the number of repeats varied among cultivars and species in the Capsicum genus. CaSD1 is constitutively expressed in roots, and Agrobacterium-mediated transient overexpression of CaSD1 in Nicotiana benthamiana leaves resulted in delayed senescence with a dramatically increased number of trichomes and enlarged epidermal cells. Furthermore, senescence- and cell division-related genes were differentially regulated by CaSD1-overexpressing plants. These observations imply that the pepper-specific cell wall protein CaSD1 plays roles in plant growth and development by regulating cell division and differentiation.

  8. Plant senescence and crop productivity

    DEFF Research Database (Denmark)

    Gregersen, Per L.; Culetic, Andrea; Boschian, Luca

    2013-01-01

    Senescence is a developmental process which in annual crop plants overlaps with the reproductive phase. Senescence might reduce crop yield when it is induced prematurely under adverse environmental conditions. This review covers the role of senescence for the productivity of crop plants....... With the aim to enhance productivity, a number of functional stay-green cultivars have been selected by conventional breeding, in particular of sorghum and maize. In many cases, a positive correlation between leaf area duration and yield has been observed, although in a number of other cases, stay...... plants, the expression of the IPT gene under control of senescence-associated promoters has been the most successful. The promoters employed for senescence-regulated expression contain cis-elements for binding of WRKY transcription factors and factors controlled by abscisic acid. In most crops...

  9. Senescence induction; a possible cancer therapy

    Directory of Open Access Journals (Sweden)

    Kondoh Hiroshi

    2009-01-01

    Full Text Available Abstract Cellular immortalization is a crucial step during the development of human cancer. Primary mammalian cells reach replicative exhaustion after several passages in vitro, a process called replicative senescence. During such a state of permanent growth arrest, senescent cells are refractory to physiological proliferation stimuli: they have altered cell morphology and gene expression patterns, although they remain viable with preserved metabolic activity. Interestingly, senescent cells have also been detected in vivo in human tumors, particularly in benign lesions. Senescence is a mechanism that limits cellular lifespan and constitutes a barrier against cellular immortalization. During immortalization, cells acquire genetic alterations that override senescence. Tumor suppressor genes and oncogenes are closely involved in senescence, as their knockdown and ectopic expression confer immortality and senescence induction, respectively. By using high throughput genetic screening to search for genes involved in senescence, several candidate oncogenes and putative tumor suppressor genes have been recently isolated, including subtypes of micro-RNAs. These findings offer new perspectives in the modulation of senescence and open new approaches for cancer therapy.

  10. Nitric oxide prevents wound-induced browning and delays senescence through inhibition of hydrogen peroxide accumulation in fresh-cut lettuce

    NARCIS (Netherlands)

    Iakimova, E.T.; Woltering, E.J.

    2015-01-01

    As a source of bioactive ingredients, lettuce is a preferable component of a healthy diet. In recent years the production of fresh-cut produce has become a fast growing business. However, the shreds are highly sensitive to wound-induced browning and premature senescence that substantially reduces th

  11. Nicotinamide prevents ultraviolet radiation-induced cellular energy loss.

    Science.gov (United States)

    Park, Joohong; Halliday, Gary M; Surjana, Devita; Damian, Diona L

    2010-01-01

    UV radiation is carcinogenic by causing mutations in the skin and also by suppressing cutaneous antitumor immunity. We previously found nicotinamide (vitamin B3) to be highly effective at reducing UV-induced immunosuppression in human volunteers, with microarray studies on in vivo irradiated human skin suggesting that nicotinamide normalizes subsets of apoptosis, immune function and energy metabolism-related genes that are downregulated by UV exposure. Using human adult low calcium temperature keratinocytes, we further investigated nicotinamide's effects on cellular energy metabolism. We found that nicotinamide prevented UV-induced cellular ATP loss and protected against UV-induced glycolytic blockade. To determine whether nicotinamide alters the effects of UV-induced oxidative stress posttranslationally, we also measured UV-induced reactive oxygen species (ROS). Nicotinamide had no effect on ROS formation, and at the low UV doses used in these studies, equivalent to ambient daily sun exposure, there was no evidence of apoptosis. Hence, nicotinamide appears to exert its UV protective effects on the skin via its role in cellular energy pathways.

  12. Selective insulin resistance in hepatocyte senescence

    Energy Technology Data Exchange (ETDEWEB)

    Aravinthan, Aloysious [Division of Gastroenterology and Hepatology, Department of Medicine, University of Cambridge, Cambridge (United Kingdom); Challis, Benjamin [Institute of Metabolic Sciences, University of Cambridge, Cambridge (United Kingdom); Shannon, Nicholas [Cancer Research UK Cambridge Institute, Cambridge (United Kingdom); Hoare, Matthew [Division of Gastroenterology and Hepatology, Department of Medicine, University of Cambridge, Cambridge (United Kingdom); Cancer Research UK Cambridge Institute, Cambridge (United Kingdom); Heaney, Judith [Division of Gastroenterology and Hepatology, Department of Medicine, University of Cambridge, Cambridge (United Kingdom); Foundation for Liver Research, Institute of Hepatology, London (United Kingdom); Alexander, Graeme J.M., E-mail: gja1000@doctors.org.uk [Division of Gastroenterology and Hepatology, Department of Medicine, University of Cambridge, Cambridge (United Kingdom)

    2015-02-01

    Insulin resistance has been described in association with chronic liver disease for decades. Hepatocyte senescence has been demonstrated in chronic liver disease and as many as 80% of hepatocytes show a senescent phenotype in advanced liver disease. The aim of this study was to understand the role of hepatocyte senescence in the development of insulin resistance. Senescence was induced in HepG2 cells via oxidative stress. The insulin metabolic pathway was studied in control and senescent cells following insulin stimulation. GLUT2 and GLUT4 expressions were studied in HepG2 cells and human liver tissue. Further, GLUT2 and GLUT4 expressions were studied in three independent chronic liver disease cohorts. Signalling impairment distal to Akt in phosphorylation of AS160 and FoxO1 was evident in senescent HepG2 cells. Persistent nuclear localisation of FoxO1 was demonstrated in senescent cells despite insulin stimulation. Increased GLUT4 and decreased GLUT2 expressions were evident in senescent cells, human cirrhotic liver tissue and publically available liver disease datasets. Changes in GLUT expressions were associated with a poor clinical prognosis. In conclusion, selective insulin resistance is evident in senescent HepG2 cells and changes in GLUT expressions can be used as surrogate markers of hepatocyte senescence. - Highlights: • Senescent hepatocytes demonstrate selective insulin resistance. • GLUT changes act as markers of hepatocyte senescence and have prognostic value. • Study offers insight into long noticed intimacy of cirrhosis and insulin resistance.

  13. [The stimulation of human pulmonary artery endothelial cells by cigarette smoke extract contributed to cell senescence and induced human pulmonary artery smooth cell migration].

    Science.gov (United States)

    Cai, L; Zhu, P C; Wang, Y E; Gao, Y T; Ao, Q L

    2017-06-12

    Objective: To observe the senescent effect of human pulmonary arterial endothelial cells (HPAEC) stimulated by cigarette smoke extract (CSE) and the effect of secretion of senescent cells on human pulmonary arterial smooth muscles cell (HPASMC) proliferation and migration. Methods: HPAEC was treated with different concentrations of CSE in vitro and cell proliferation was determined by CCK8, senescence cells analyzed by detecting the β-gal activity, and the senescent proteins of cells measured by Western blot. The concentration of senescence-associated secretory phenotype (SASP) was detected by ELISA and the expression of MCP-1 and TGF-β1 was measured by Real-time PCR. The number of the proliferated cells was measured by Transwell assay and immunoflurescence. Results: The HPAEC was aging with the stimulation concentration of CSE increasing and the stimulation time prolonging (Pcells increased as the exposure time prolonged. Compared with the control group, cell viability of 48 h group(1.8±0.1) and 72 h group (1.8±0.1) decreased significantly. The flow cytometry showed a significant difference between the CSE group(14.1±1.2) and the control group(28.5±1.8) in S phase(Pcell cycle arrest. The SASP was increasing as the CSE-exposure prolonged. Compared with the control group(177±39), the 48 h group(460±43) and the 72 h group(609±64) showed a marked increase in MCP-1(Pcells could secrete SASP which induced HPASMC proliferation. After different times of conditioned medium stimulation, HPASMC proliferated especially at 72 h(P<0.05) . The immnoflorescence and Transwell assay confirmed this finding. Conclusion: CSE could induce senescence of HPAEC and SASP production which improved HPASMC proliferation and migration.

  14. Oncogenic senescence: a multi-functional perspective

    NARCIS (Netherlands)

    Baker, D.J.; Alimirah, F.; Deursen, J.M.A. van; Campisi, J.; Hildesheim, J.

    2017-01-01

    Cellular senescence is defined as an irreversible growth arrest with the acquisition of a distinctive secretome. The growth arrest is a potent anticancer mechanism whereas the secretome facilitates wound healing, tissue repair, and development. The senescence response has also become increasingly

  15. Marcadores de senescencia celular en cáncer y precáncer oral Cellular senescence markers in oral cancer and precancer

    Directory of Open Access Journals (Sweden)

    J. Campo-Trapero

    2008-02-01

    Full Text Available Estudios recientes han demostrado la capacidad del organismo humano para detener el crecimiento de potenciales células cancerígenas y paralizarlas. Este mecanismo antitumoral, que actúa como freno del proceso maligno, se conocía ya en estudios de laboratorio "in vitro", pero se ha comprobado también su presencia en modelos "in vivo", tanto en ratones como en muestras de tejido de pacientes con cáncer. A este mecanismo se le denomina senescencia celular y se define como un sistema de defensa de emergencia de las células que están en camino de convertirse en cancerosas, una respuesta ante el estímulo de un oncogén. Se trataría pues de un freno a la progresión de las lesiones cancerizables, condenando a esas células a una "cadena perpetua celular". Este artículo de revisión se propone describir este mecanismo y poner al día la evidencia al respecto de este proceso, así como los marcadores de senescencia existentes en relación con el cáncer y precáncer oral.Recent studies have demonstrated the capacity of the human organism to prevent the growth of potentially carcinogenic cells, paralyzing them. This antitumor mechanism, which acts as a brake on the malignant process, was already known in lab studies "in vitro" but has now also been verified "in vivo" in mice and in tissue samples from cancer patients. This mechanism is known as cellular senescence and is defined as an emergency defense system for cells on the way to becoming cancerous, i.e., a response to the stimulation of an oncogene. These cells are sentenced to "life imprisonment", impeding the progression of premalignant lesions. This review aims to describe this mechanism and present an update of the evidence on this phenomenon in the setting of oral cancer and precancer.

  16. Senescence-Associated Secretory Phenotypes Reveal Cell-Nonautonomous Functions of Oncogenic RAS and the p53 Tumor Suppressor

    Energy Technology Data Exchange (ETDEWEB)

    Copp& #233; , Jean-Philippe; Patil, Christopher; Rodier, Francis; Sun, Yu; Munoz, Denise; Goldstein, Joshua; Nelson, Peter; Desprez, Pierre-Yves; Campisi, Judith

    2008-10-24

    Cellular senescence suppresses cancer by arresting cell proliferation, essentially permanently, in response to oncogenic stimuli, including genotoxic stress. We modified the use of antibody arrays to provide a quantitative assessment of factors secreted by senescent cells. We show that human cells induced to senesce by genotoxic stress secrete myriad factors associated with inflammation and malignancy. This senescence-associated secretory phenotype (SASP) developed slowly over several days and only after DNA damage of sufficient magnitude to induce senescence. Remarkably similar SASPs developed in normal fibroblasts, normal epithelial cells, and epithelial tumor cells after genotoxic stress in culture, and in epithelial tumor cells in vivo after treatment of prostate cancer patients with DNA-damaging chemotherapy. In cultured premalignant epithelial cells, SASPs induced an epithelial-mesenchyme transition and invasiveness, hallmarks of malignancy, by a paracrine mechanism that depended largely on the SASP factors interleukin (IL)-6 and IL-8. Strikingly, two manipulations markedly amplified, and accelerated development of, the SASPs: oncogenic RAS expression, which causes genotoxic stress and senescence in normal cells, and functional loss of the p53 tumor suppressor protein. Both loss of p53 and gain of oncogenic RAS also exacerbated the promalignant paracrine activities of the SASPs. Our findings define a central feature of genotoxic stress-induced senescence. Moreover, they suggest a cell-nonautonomous mechanism by which p53 can restrain, and oncogenic RAS can promote, the development of age-related cancer by altering the tissue microenvironment.

  17. Senescence-associated secretory phenotypes reveal cell-nonautonomous functions of oncogenic RAS and the p53 tumor suppressor.

    Directory of Open Access Journals (Sweden)

    Jean-Philippe Coppé

    2008-12-01

    Full Text Available Cellular senescence suppresses cancer by arresting cell proliferation, essentially permanently, in response to oncogenic stimuli, including genotoxic stress. We modified the use of antibody arrays to provide a quantitative assessment of factors secreted by senescent cells. We show that human cells induced to senesce by genotoxic stress secrete myriad factors associated with inflammation and malignancy. This senescence-associated secretory phenotype (SASP developed slowly over several days and only after DNA damage of sufficient magnitude to induce senescence. Remarkably similar SASPs developed in normal fibroblasts, normal epithelial cells, and epithelial tumor cells after genotoxic stress in culture, and in epithelial tumor cells in vivo after treatment of prostate cancer patients with DNA-damaging chemotherapy. In cultured premalignant epithelial cells, SASPs induced an epithelial-mesenchyme transition and invasiveness, hallmarks of malignancy, by a paracrine mechanism that depended largely on the SASP factors interleukin (IL-6 and IL-8. Strikingly, two manipulations markedly amplified, and accelerated development of, the SASPs: oncogenic RAS expression, which causes genotoxic stress and senescence in normal cells, and functional loss of the p53 tumor suppressor protein. Both loss of p53 and gain of oncogenic RAS also exacerbated the promalignant paracrine activities of the SASPs. Our findings define a central feature of genotoxic stress-induced senescence. Moreover, they suggest a cell-nonautonomous mechanism by which p53 can restrain, and oncogenic RAS can promote, the development of age-related cancer by altering the tissue microenvironment.

  18. Ectopic Expression of Capsicum-Specific Cell Wall Protein Capsicum annuum Senescence-Delaying 1 (CaSD1) Delays Senescence and Induces Trichome Formation in Nicotiana benthamiana

    OpenAIRE

    Seo, Eunyoung; Yeom, Seon-In; Jo, SungHwan; Jeong, Heejin; Kang, Byoung-Cheorl; Choi, Doil

    2012-01-01

    Secreted proteins are known to have multiple roles in plant development, metabolism, and stress response. In a previous study to understand the roles of secreted proteins, Capsicum annuum secreted proteins (CaS) were isolated by yeast secretion trap. Among the secreted proteins, we further characterized Capsicum annuum senescence-delaying 1 (CaSD1), a gene encoding a novel secreted protein that is present only in the genus Capsicum. The deduced CaSD1 contains multiple repeats of the amino aci...

  19. HBP1-Mediated Transcriptional Regulation of DNA Methyltransferase 1 and Its Impact on Cell Senescence

    Science.gov (United States)

    Pan, Kewu; Chen, Yifan; Roth, Mendel; Wang, Weibin; Wang, Shuya; Yee, Amy S.

    2013-01-01

    The activity of DNA methyltransferase 1 (DNMT1) is associated with diverse biological activities, including cell proliferation, senescence, and cancer development. In this study, we demonstrated that the HMG box-containing protein 1 (HBP1) transcription factor is a new repressor of DNMT1 in a complex mechanism during senescence. The DNMT1 gene contains an HBP1-binding site at bp −115 to −134 from the transcriptional start site. HBP1 repressed the endogenous DNMT1 gene through sequence-specific binding, resulting in both gene-specific (e.g., p16INK4) and global DNA hypomethylation changes. The HBP1-mediated repression by DNMT1 contributed to replicative and premature senescence, the latter of which could be induced by Ras and HBP1 itself. A detailed investigation unexpectedly revealed that HBP1 has dual and complex transcriptional functions, both of which contribute to premature senescence. HBP1 both repressed the DNMT1 gene and activated the p16 gene in premature senescence. The opposite transcriptional functions proceeded through different DNA sequences and differential protein acetylation. While intricate, the reciprocal partnership between HBP1 and DNMT1 has exceptional importance, since its abrogation compromises senescence and promotes tumorigenesis. Together, our results suggest that the HBP1 transcription factor orchestrates a complex regulation of key genes during cellular senescence, with an impact on overall DNA methylation state. PMID:23249948

  20. Induction of Extracellular Matrix-Remodeling Genes by the Senescence-Associated Protein APA-1

    Science.gov (United States)

    Benanti, Jennifer A.; Williams, Dawnnica K.; Robinson, Kristin L.; Ozer, Harvey L.; Galloway, Denise A.

    2002-01-01

    Human fibroblasts undergo cellular senescence after a finite number of divisions, in response to the erosion of telomeres. In addition to being terminally arrested in the cell cycle, senescent fibroblasts express genes that are normally induced upon wounding, including genes that remodel the extracellular matrix. We have identified the novel zinc finger protein APA-1, whose expression increased in senescent human fibroblasts independent of telomere shortening. Extended passage, telomerase-immortalized fibroblasts had increased levels of APA-1 as well as the cyclin-dependent kinase inhibitor p16. In fibroblasts, APA-1 was modified by the ubiquitin-like protein SUMO-1, which increased APA-1 half-life, possibly by blocking ubiquitin-mediated degradation. Overexpression of APA-1 did not cause cell cycle arrest; but, it induced transcription of the extracellular matrix-remodeling genes MMP1 and PAI2, which are associated with fibroblast senescence. MMP1 and PAI2 transcript levels also increased in telomerase-immortalized fibroblasts that had high levels of APA-1, demonstrating that the matrix-remodeling phenotype of senescent fibroblasts was not induced by telomere attrition alone. APA-1 was able to transactivate and bind to the MMP1 promoter, suggesting that APA-1 is a transcription factor that regulates expression of matrix-remodeling genes during fibroblast senescence. PMID:12370286

  1. p53/p21 Pathway involved in mediating cellular senescence of bone marrow-derived mesenchymal stem cells from systemic lupus erythematosus patients.

    Science.gov (United States)

    Gu, Zhifeng; Jiang, Jinxia; Tan, Wei; Xia, Yunfei; Cao, Haixia; Meng, Yan; Da, Zhanyun; Liu, Hong; Cheng, Chun

    2013-01-01

    Our and other groups have found that bone marrow-derived mesenchymal stem cells (BM-MSCs) from systemic lupus erythematosus (SLE) patients exhibited senescent behavior and are involved in the pathogenesis of SLE. Numerous studies have shown that activation of the p53/p21 pathway inhibits the proliferation of BM-MSCs. The aim of this study was to determine whether p53/p21 pathway is involved in regulating the aging of BM-MSCs from SLE patients and the underlying mechanisms. We further confirmed that BM-MSCs from SLE patients showed characteristics of senescence. The expressions of p53 and p21 were significantly increased, whereas levels of Cyclin E, cyclin-dependent kinase-2, and phosphorylation of retinoblastoma protein were decreased in the BM-MSCs from SLE patients and knockdown of p21 expression reversed the senescent features of BM-MSCs from SLE patients. Our results demonstrated that p53/p21 pathway played an important role in the senescence process of BM-MSCs from SLE.

  2. p53/p21 Pathway Involved in Mediating Cellular Senescence of Bone Marrow-Derived Mesenchymal Stem Cells from Systemic Lupus Erythematosus Patients

    Directory of Open Access Journals (Sweden)

    Zhifeng Gu

    2013-01-01

    Full Text Available Our and other groups have found that bone marrow-derived mesenchymal stem cells (BM-MSCs from systemic lupus erythematosus (SLE patients exhibited senescent behavior and are involved in the pathogenesis of SLE. Numerous studies have shown that activation of the p53/p21 pathway inhibits the proliferation of BM-MSCs. The aim of this study was to determine whether p53/p21 pathway is involved in regulating the aging of BM-MSCs from SLE patients and the underlying mechanisms. We further confirmed that BM-MSCs from SLE patients showed characteristics of senescence. The expressions of p53 and p21 were significantly increased, whereas levels of Cyclin E, cyclin-dependent kinase-2, and phosphorylation of retinoblastoma protein were decreased in the BM-MSCs from SLE patients and knockdown of p21 expression reversed the senescent features of BM-MSCs from SLE patients. Our results demonstrated that p53/p21 pathway played an important role in the senescence process of BM-MSCs from SLE.

  3. Modulating effect of SIRT1 activation induced by resveratrol on Foxo1-associated apoptotic signalling in senescent heart.

    Science.gov (United States)

    Sin, Thomas K; Yu, Angus P; Yung, Benjamin Y; Yip, Shea Ping; Chan, Lawrence W; Wong, Cesar S; Ying, Michael; Rudd, John A; Siu, Parco M

    2014-06-15

    Elevations of cardiomyocyte apoptosis and fibrotic deposition are major characteristics of the ageing heart. Resveratrol, a polyphenol in grapes and red wine, is known to improve insulin resistance and increase mitochondrial biogenesis through the SIRT1-PGC-1α signalling axis. Recent studies attempted to relate SIRT1 activation by resveratrol to the regulation of apoptosis in various disease models of cardiac muscle. In the present study, we tested the hypothesis that long-term (8-month) treatment of resveratrol would activate SIRT1 and improve the cardiac function of senescent mice through suppression of Foxo1-associated pro-apoptotic signalling. Our echocardiographic measurements indicated that the cardiac systolic function measured as fractional shortening and ejection fraction was significantly reduced in aged mice when compared with the young mice. These reductions, however, were not observed in resveratrol-treated hearts. Ageing significantly reduced the deacetylase activity, but not the protein abundance of SIRT1 in the heart. This reduction was accompanied by increased acetylation of the Foxo1 transcription factor and transactivation of its target, pro-apoptotic Bim. Subsequent analyses indicated that pro-apoptotic signalling measured as p53, Bax and apoptotic DNA fragmentation was up-regulated in the heart of aged mice. In contrast, resveratrol restored SIRT1 activity and suppressed elevations of Foxo1 acetylation, Bim and pro-apoptotic signalling in the aged heart. In parallel, resveratrol also attenuated the ageing-induced elevations of fibrotic collagen deposition and markers of oxidative damage including 4HNE and nitrotyrosine. In conclusion, these novel data demonstrate that resveratrol mitigates pro-apoptotic signalling in senescent heart through a deacetylation mechanism of SIRT1 that represses the Foxo1-Bim-associated pro-apoptotic signalling axis.

  4. N-Stearoyl-L-Tyrosine Inhibits the Senescence of Neural Stem/Progenitor Cells Induced by Aβ1–42 via the CB2 Receptor

    Directory of Open Access Journals (Sweden)

    Wen-Qing Li

    2016-01-01

    Full Text Available Alzheimer’s disease, one of the neurodegenerative diseases, shows the progressive senescence of neural progenitor/stem cells. N-Stearoyl-L-tyrosine (NsTyr showed neuroprotective effect against chronic brain ischemia in previous reports. In the present study, we find the antisenescent effects of NsTyr-2K in NSPCs induced by Aβ1–42 in vitro. Cell viability of NSPCs was evaluated by CCK8 assay; SA-β-gal staining was used to evaluate senescence of NSPCs. CB receptors were detected by immunohistochemistry in NSPCs. AM251 or AM630 was used to offset the anti-senescence effects afforded by NsTyr-2K. The positive rate of SA-β-gal staining was significantly increased in NSPCs after incubation with Aβ1–42 for 9 days. CB receptors were found on the surface of NSPCs. The expression level of CB1 receptors was significantly decreased in NSPCs after incubation with Aβ1–42. This phenomenon was reversed dose-dependently by NsTyr-2K. NsTyr-2K attenuated Aβ1–42 induced NSPCs senescence dose-dependently, and its antisenescence effect was completely abolished by AM630. Aβ1–42 dose-dependently increased the prosenescence molecules p16 and Rb. Their expression was inhibited by NsTyr-2K dose-dependently and blocked by AM630 in NSPCs. These results suggest that NsTyr-2K can alleviate the senescence of NSPCs induced by Aβ1–42 via CB2 receptor.

  5. Inhibition of the K+ channel K(Ca3.1 reduces TGF-β1-induced premature senescence, myofibroblast phenotype transition and proliferation of mesangial cells.

    Directory of Open Access Journals (Sweden)

    Rong-Guo Fu

    Full Text Available OBJECTIVE: K(Ca3.1 channel participates in many important cellular functions. This study planned to investigate the potential involvement of K(Ca3.1 channel in premature senescence, myofibroblast phenotype transition and proliferation of mesangial cells. METHODS & MATERIALS: Rat mesangial cells were cultured together with TGF-β1 (2 ng/ml and TGF-β1 (2 ng/ml + TRAM-34 (16 nM separately for specified times from 0 min to 60 min. The cells without treatment served as controls. The location of K(Ca3.1 channels in mesangial cells was determined with Confocal laser microscope, the cell cycle of mesangial cells was assessed with flow cytometry, the protein and mRNA expression of K(Ca3.1, α-smooth muscle actin (α-SMA and fibroblast-specific protein-1 (FSP-1 were detected with Western blot and RT-PCR. One-way analysis of variance (ANOVA and Student-Newman-Keuls-q test (SNK-q were used to do statistical analysis. Statistical significance was considered at P<0.05. RESULTS: Kca3.1 channels were located in the cell membranes and/or in the cytoplasm of mesangial cells. The percentage of cells in G0-G1 phase and the expression of K(ca3.1, α-SMA and FSP-1 were elevated under the induction of TGF-β1 when compared to the control and decreased under the induction of TGF-β1+TRAM-34 when compared to the TGF-β1 induced (P<0.05 or P<0.01. CONCLUSION: Targeted disruption of K(Ca3.1 inhibits TGF-β1-induced premature aging, myofibroblast-like phenotype transdifferentiation and proliferation of mesangial cells.

  6. Jasmonates during senescence: signals or products of metabolism?

    Science.gov (United States)

    Seltmann, Martin A; Hussels, Wiebke; Berger, Susanne

    2010-11-01

    Jasmonic acid and derivatives are oxylipin signaling compounds derived from linolenic acid. Jasmonates accumulate during natural and dark-induced senescence but the increase in these compounds is not essential for the initiation or progression of these senescence processes. Here we report that during natural and dark-induced senescence the increase in jasmonate levels does not trigger jasmonate signaling. Furthermore we provide evidence that jasmonate production might result from membrane turnover during dark-induced senescence.

  7. Phenotyping jasmonate regulation of senescence.

    Science.gov (United States)

    Seltmann, Martin A; Berger, Susanne

    2013-01-01

    Osmotic stress induces several senescence-like processes in leaves, such as specific changes in gene expression and yellowing. These processes are dependent on the accumulation of jasmonates and on intact jasmonate signaling. This chapter describes the treatment of Arabidopsis thaliana leaves with sorbitol as an osmotic stress agent and the determination of the elicited phenotypes encompassing chlorophyll loss, degradation of plastidial membrane lipids, and induction of genes regulated by senescence and jasmonate.

  8. A Micro-RNA Connection in BRafV600E-Mediated Premature Senescence of Human Melanocytes

    Directory of Open Access Journals (Sweden)

    Gang Ren

    2012-01-01

    Full Text Available Recent high-throughput-sequencing of the cancer genome has identified oncogenic mutations in BRaf genetic locus as one of the critical events in melanomagenesis. In normal cells, the activity of BRaf is tightly regulated. Gain-of-function mutations like those identified in melanoma frequently lead to enhanced cell-survival and unrestrained growth. The activating mutation of BRaf will also induce the cells to senesce. However, the mechanism by which the oncogenic BRaf induces the senescent barrier remains poorly defined. microRNAs have regulatory functions toward the expression of genes that are important in carcinogenesis. Here we show that expression of several microRNAs is altered when the oncogenic version of BRaf is introduced in cultured primary melanocytes and these cells undergo premature cellular senescence. These include eight microRNAs whose expression rates are significantly stimulated and three that are repressed. While most of the induced microRNAs have documented negative effects on cell cycle progression, one of the repressed microRNAs has proven oncogenic functions. Ectopic expression of some of these induced microRNAs increased the expression of senescence markers and induced growth arrest and senescence in primary melanocytes. Taken together, our results suggest that the change in microRNA expression rates may play a vital role in senescence induced by the oncogenic BRaf.

  9. A hyaluronic acid-based compound inhibits fibroblast senescence induced by oxidative stress in vitro and prevents oral mucositis in vivo.

    Science.gov (United States)

    Cirillo, Nicola; Vicidomini, Antonio; McCullough, Michael; Gambardella, Antonio; Hassona, Yazan; Prime, Stephen S; Colella, Giuseppe

    2015-07-01

    Virtually all patients receiving radio- and chemotherapy for cancer develop oral mucositis, a severe and highly debilitating condition. The onset of mucositis is thought to involve the production of reactive oxygen species (ROS) in the submucosa. Here we investigated a possible protective effect of a commercial formulation of hyaluronic acid (HA) enriched with amino acids (Mucosamin(®)) against the damage induced by oxidative stress both in vitro and in vivo. Transient exposure of normal human oral fibroblasts to hydrogen peroxide (H(2)O(2)) led to irreversible senescence, as demonstrated by sustained increase in the levels of p16(INK4A) and SA-βGal. Conditioned media from senescent fibroblasts induced detrimental effects on keratinocytes, as shown by reduced metabolic activity and migration capability. Pre-treatment with Mucosamin(®) prevented H(2)O(2) -induced, but not TGF-β-induced, fibroblast senescence with a concomitant reduction of fibroblast-induced loss of keratinocyte vitality and functional activity. Finally, data from a case-series of patients undergoing radio/chemotherapy strongly suggested that prophylactic use of the hyaluronic acid-based compound in the form of a spray may be effective in preventing the onset of oral mucositis.

  10. The H3K27me3 demethylase JMJD3 contributes to the activation of the INK4A-ARF locus in response to oncogene- and stress-induced senescence

    DEFF Research Database (Denmark)

    Agger, Karl; Cloos, Paul A C; Rudkjaer, Lise

    2009-01-01

    The tumor suppressor proteins p16INK4A and p14ARF, encoded by the INK4A-ARF locus, are key regulators of cellular senescence. The locus is epigenetically silenced by the repressive H3K27me3 mark in normally growing cells, but becomes activated in response to oncogenic stress. Here, we show...... that expression of the histone H3 Lys 27 (H3K27) demethylase JMJD3 is induced upon activation of the RAS-RAF signaling pathway. JMJD3 is recruited to the INK4A-ARF locus and contributes to the transcriptional activation of p16INK4A in human diploid fibroblasts. Additionally, inhibition of Jmjd3 expression...... in mouse embryonic fibroblasts results in suppression of p16Ink4a and p19Arf expression and in their immortalization....

  11. Labellum transcriptome reveals alkene biosynthetic genes involved in orchid sexual deception and pollination-induced senescence.

    Science.gov (United States)

    Monteiro, Filipa; Sebastiana, Mónica; Figueiredo, Andreia; Sousa, Lisete; Cotrim, Helena C; Pais, Maria Salomé

    2012-11-01

    One of the most remarkable pollination strategy in orchids biology is pollination by sexual deception, in which the modified petal labellum lures pollinators by mimicking the chemical (e.g. sex pheromones), visual (e.g. colour and shape/size) and tactile (e.g. labellum trichomes) cues of the receptive female insect species. The present study aimed to characterize the transcriptional changes occurring after pollination in the labellum of a sexually deceptive orchid (Ophrys fusca Link) in order to identify genes involved on signals responsible for pollinator attraction, the major goal of floral tissues. Novel information on alterations in the orchid petal labellum gene expression occurring after pollination demonstrates a reduction in the expression of alkene biosynthetic genes using O. fusca Link as the species under study. Petal labellum transcriptional analysis revealed downregulation of transcripts involved in both pigment machinery and scent compounds, acting as visual and olfactory cues, respectively, important in sexual mimicry. Regulation of petal labellum senescence was revealed by transcripts related to macromolecules breakdown, protein synthesis and remobilization of nutrients.

  12. A screen identifies the oncogenic micro-RNA miR-378a-5p as a negative regulator of oncogene-induced senescence.

    Directory of Open Access Journals (Sweden)

    Susanne Marije Kooistra

    Full Text Available Oncogene-induced senescence (OIS can occur in response to hyperactive oncogenic signals and is believed to be a fail-safe mechanism protecting against tumorigenesis. To identify new factors involved in OIS, we performed a screen for microRNAs that can overcome or inhibit OIS in human diploid fibroblasts. This screen led to the identification of miR-378a-5p and in addition several other miRNAs that have previously been shown to play a role in senescence. We show that ectopic expression of miR-378a-5p reduces the expression of several senescence markers, including p16(INK4A and senescence-associated β-galactosidase. Moreover, cells with ectopic expression of miR-378a-5p retain proliferative capacity even in the presence of an activated Braf oncogene. Finally, we identified several miR-378a-5p targets in diploid fibroblasts that might explain the mechanism by which the microRNA can delay OIS. We speculate that miR-378a-5p might positively influence tumor formation by delaying OIS, which is consistent with a known pro-oncogenic function of this microRNA.

  13. A Screen Identifies the Oncogenic Micro-RNA miR-378a-5p as a Negative Regulator of Oncogene-Induced Senescence

    DEFF Research Database (Denmark)

    Kooistra, Susanne Marije; Rudkjær, Lise Christine; Lees, Michael James

    2014-01-01

    fibroblasts. This screen led to the identification of miR-378a-5p and in addition several other miRNAs that have previously been shown to play a role in senescence. We show that ectopic expression of miR-378a-5p reduces the expression of several senescence markers, including p16INK4A and senescence......Oncogene-induced senescence (OIS) can occur in response to hyperactive oncogenic signals and is believed to be a fail-safe mechanism protecting against tumorigenesis. To identify new factors involved in OIS, we performed a screen for microRNAs that can overcome or inhibit OIS in human diploid......-associated β-galactosidase. Moreover, cells with ectopic expression of miR-378a-5p retain proliferative capacity even in the presence of an activated Braf oncogene. Finally, we identified several miR-378a-5p targets in diploid fibroblasts that might explain the mechanism by which the microRNA can delay OIS. We...

  14. Telomerase prevents accelerated senescence in glucose-6-phosphate dehydrogenase (G6PD-deficient human fibroblasts

    Directory of Open Access Journals (Sweden)

    Wu Yi-Hsuan

    2009-02-01

    Full Text Available Abstract Fibroblasts derived from glucose-6-phosphate dehydrogenase (G6PD-deficient patients display retarded growth and accelerated cellular senescence that is attributable to increased accumulation of oxidative DNA damage and increased sensitivity to oxidant-induced senescence, but not to accelerated telomere attrition. Here, we show that ectopic expression of hTERT stimulates telomerase activity and prevents accelerated senescence in G6PD-deficient cells. Stable clones derived from hTERT-expressing normal and G6PD-deficient fibroblasts have normal karyotypes, and display no sign of senescence beyond 145 and 105 passages, respectively. Activation of telomerase, however, does not prevent telomere attrition in earlier-passage cells, but does stabilize telomere lengths at later passages. In addition, we provide evidence that ectopic expression of hTERT attenuates the increased sensitivity of G6PD-deficient fibroblasts to oxidant-induced senescence. These results suggest that ectopic expression of hTERT, in addition to acting in telomere length maintenance by activating telomerase, also functions in regulating senescence induction.

  15. YUCCA6 over-expression demonstrates auxin function in delaying leaf senescence in Arabidopsis thaliana

    KAUST Repository

    Kim, Jeong Im

    2011-04-21

    The Arabidopsis thaliana YUCCA family of flavin monooxygenase proteins catalyses a rate-limiting step in de novo auxin biosynthesis. A YUCCA6 activation mutant, yuc6-1D, has been shown to contain an elevated free IAA level and to display typical high-auxin phenotypes. It is reported here that Arabidopsis plants over-expressing YUCCA6, such as the yuc6-1D activation mutant and 35S:YUC6 transgenic plants, displayed dramatic longevity. In addition, plants over-expressing YUCCA6 exhibited classical, delayed dark-induced and hormone-induced senescence in assays using detached rosette leaves. However, plants over-expressing an allele of YUCCA6, that carries mutations in the NADPH cofactor binding site, exhibited neither delayed leaf senescence phenotypes nor phenotypes typical of auxin overproduction. When the level of free IAA was reduced in yuc6-1D by conjugation to lysine, yuc6-1D leaves senesced at a rate similar to the wild-type leaves. Dark-induced senescence in detached leaves was accompanied by a decrease in their free IAA content, by the reduced expression of auxin biosynthesis enzymes such as YUCCA1 and YUCCA6 that increase cellular free IAA levels, and by the increased expression of auxin-conjugating enzymes encoded by the GH3 genes that reduce the cellular free auxin levels. Reduced transcript abundances of SAG12, NAC1, and NAC6 during senescence in yuc6-1D compared with the wild type suggested that auxin delays senescence by directly or indirectly regulating the expression of senescence-associated genes. 2011 The Author(s).

  16. High-throughput microcavitation bubble induced cellular mechanotransduction

    Science.gov (United States)

    Compton, Jonathan Lee

    inhibitor to IP 3 induced Ca2+ release. This capability opens the development of a high-throughput screening platform for molecules that modulate cellular mechanotransduction. We have applied this approach to screen the effects of a small set of small molecules, in a 96-well plate in less than an hour. These detailed studies offer a basis for the design, development, and implementation of a novel high-throughput mechanotransduction assay to rapidly screen the effect of small molecules on cellular mechanotransduction at high throughput.

  17. Diosmin-induced senescence, apoptosis and autophagy in breast cancer cells of different p53 status and ERK activity.

    Science.gov (United States)

    Lewinska, Anna; Adamczyk-Grochala, Jagoda; Kwasniewicz, Ewa; Deregowska, Anna; Wnuk, Maciej

    2017-01-04

    Relatively low bioavailability of plant-derived nutraceuticals with anticancer properties may limit their usefulness for prevention and therapy of cancer. In the present study, we have screened for nutraceuticals (n=30) that would act at low micromolar range against phenotypically distinct breast cancer cell lines, namely MCF-7 (ER(+), PR(+/-), HER2(-)), MDA-MB-231 (ER(-), PR(-), HER2(-)) and SK-BR-3 (ER(-), PR(-), HER2(+)), and diosmin, a citrus fruit flavonoid belonging to a flavone subclass, was selected. MCF-7 cell line was found to be the most sensitive to diosmin treatment. Diosmin caused G2/M cell cycle arrest, elevation in p53, p21 and p27 levels and stress-induced premature senescence when used at lower concentrations (5 and 10μM). Diosmin (20μM) also promoted apoptosis that was not observed in normal human mammary epithelial cells (HMEC). Diosmin stimulated oxidative and nitrosative stress, DNA damage and changes in global DNA methylation patterns. The status of p53 (wild type versus mutant) and the levels of phosphorylated ERK1/2 in a steady state, and diosmin-induced autophagy may reflect diverse response to diosmin treatment in MCF-7, MDA-MB-231 and SK-BR-3 cells, which in turn results in different cell fates. Taken together, diosmin that acts at low micromolar range against breast cancer cells may be considered as a promising candidate for anticancer therapy.

  18. Senescence mechanisms induced by phloem girdling inKarelinia caspia%韧皮部环割诱导下的花花柴衰老机制

    Institute of Scientific and Technical Information of China (English)

    顾祝禹; 唐钢梁; 艾克拜尔·伊拉洪; 吐尔逊·吐尔洪

    2015-01-01

    Aims Senescence constitutes the final stage of a plant’s organ and tissue development, and is subject to gene control and strict regulation. Plant senescence is largely influenced by carbohydrate content and phloem girdling can induce leaf senescence. Our general objective is to study the effect of stem girdling on physiological condi-tions inKarelinia caspia. Specifically, we want to know the senescence processes after phloem girdling. In addi-tion, we also want to know the possible mechanisms for the senescence processes. Methods Three different types of girdling treatments, normal branch, semi-girdling, and full-girdling were per-formed onK. caspia. Twenty days after girdling, photosynthetic pigments content, photosynthetic rate, soluble sugar content, starch content, abscisic acid (ABA) content, and leaf water potential were measured. Important findings Phloem girdling can largely induce leaf senescence inK. caspia, and the reasons for leaf senescence may be as follows: girdling resulted in carbohydrate accumulation in leaf which subsequently led to “carbon feast” induced leaf senescence; girdling caused ABA accumulation in leaf and then resulted in senes-cence; girdling decreased water status, which may be another reason for leaf senescence. Compared with natural senescence, girdling induced senescence was a disorder and disorganized process, only a limited physiological process can be controlled by senescence related gene in the girdling induced senescence process. The most im-portant role for carotenoids in the senescence process is to protect the photosynthetic apparatus from being dam-aged by excess light and reactive oxygen species. Many physiological indicators declined in the semi-girdledK. caspia leaves just like full-girdled leaves, indicating that portion (e.g. half) of the phloem cannot undertake the transport flux which was done by the whole phloem sieve.%衰老是植物器官和组织发育的最后阶段,是一个受到严格控制的

  19. Identification of hub genes of pneumocyte senescence induced by thoracic irradiation using weighted gene co-expression network analysis

    Science.gov (United States)

    XING, YONGHUA; ZHANG, JUNLING; LU, LU; LI, DEGUAN; WANG, YUEYING; HUANG, SONG; LI, CHENGCHENG; ZHANG, ZHUBO; LI, JIANGUO; MENG, AIMIN

    2016-01-01

    Irradiation commonly causes pneumocyte senescence, which may lead to severe fatal lung injury characterized by pulmonary dysfunction and respiratory failure. However, the molecular mechanism underlying the induction of pneumocyte senescence by irradiation remains to be elucidated. In the present study, weighted gene co-expression network analysis (WGCNA) was used to screen for differentially expressed genes, and to identify the hub genes and gene modules, which may be critical for senescence. A total of 2,916 differentially expressed genes were identified between the senescence and non-senescence groups following thoracic irradiation. In total, 10 gene modules associated with cell senescence were detected, and six hub genes were identified, including B-cell scaffold protein with ankyrin repeats 1, translocase of outer mitochondrial membrane 70 homolog A, actin filament-associated protein 1, Cd84, Nuf2 and nuclear factor erythroid 2. These genes were markedly associated with cell proliferation, cell division and cell cycle arrest. The results of the present study demonstrated that WGCNA of microarray data may provide further insight into the molecular mechanism underlying pneumocyte senescence. PMID:26572216

  20. BRAF Mutation Is Associated With a Specific Cell Type With Features Suggestive of Senescence in Ovarian Serous Borderline (Atypical Proliferative) Tumors

    DEFF Research Database (Denmark)

    Zeppernick, Felix; Ardighieri, Laura; Hannibal, Charlotte G

    2014-01-01

    . Immunohistochemistry showed that the EC cells always expressed p16, a senescence-associated marker, and had a significantly lower Ki-67 labeling index than adjacent cuboidal and columnar cells (P=0.02). In vitro studies supported the interpretation that these cells were undergoing senescence, as the same morphologic...... features could be reproduced in cultured epithelial cells by ectopic expression of BRAF(V600E). Senescence was further established by markers such as SA-β-gal staining, expression of p16 and p21, and reduction in DNA synthesis. In conclusion, this study sheds light on the pathogenesis of this unique group...... of ovarian tumors by showing that BRAF mutation is associated with cellular senescence and the presence of a specific cell type characterized by abundant EC. This "oncogene-induced senescence" phenotype may represent a mechanism that impedes progression of APSTs to LGSC....

  1. Glucose metabolite glyoxal induces senescence in telomerase-immortalized human mesenchymal stem cells

    DEFF Research Database (Denmark)

    Larsen, Simon Asbjørn; Kassem, Moustapha; Rattan, Suresh

    2012-01-01

    Background Various by-products of the cellular metabolism, such as reactive carbonyl species (RCS) are potentially harmful to cells and tissues, and play a role in many physiological and pathological processes. Among various RCS is the highly reactive dicarbonyl glyoxal (GO), which is a natural p...

  2. In response to partial plant shading, the lack of phytochrome A does not directly induce leaf senescence but alters the fine-tuning of chlorophyll biosynthesis.

    Science.gov (United States)

    Brouwer, Bastiaan; Gardeström, Per; Keech, Olivier

    2014-07-01

    Phytochrome is thought to control the induction of leaf senescence directly, however, the signalling and molecular mechanisms remain unclear. In the present study, an ecophysiological approach was used to establish a functional connection between phytochrome signalling and the physiological processes underlying the induction of leaf senescence in response to shade. With shade it is important to distinguish between complete and partial shading, during which either the whole or only a part of the plant is shaded, respectively. It is first shown here that, while PHYB is required to maintain chlorophyll content in a completely shaded plant, only PHYA is involved in maintaining the leaf chlorophyll content in response to partial plant shading. Second, it is shown that leaf yellowing associated with strong partial shading in phyA-mutant plants actually correlates to a decreased biosynthesis of chlorophyll rather than to an increase of its degradation. Third, it is shown that the physiological impact of this decreased biosynthesis of chlorophyll in strongly shaded phyA-mutant leaves is accompanied by a decreased capacity to adjust the Light Compensation Point. However, the increased leaf yellowing in phyA-mutant plants is not accompanied by an increase of senescence-specific molecular markers, which argues against a direct role of PHYA in inducing leaf senescence in response to partial shade. In conclusion, it is proposed that PHYA, but not PHYB, is essential for fine-tuning the chlorophyll biosynthetic pathway in response to partial shading. In turn, this mechanism allows the shaded leaf to adjust its photosynthetic machinery to very low irradiances, thus maintaining a positive carbon balance and repressing the induction of leaf senescence, which can occur under prolonged periods of shade.

  3. Beryllium sulfate induces p21 CDKN1A expression and a senescence-like cell cycle arrest in susceptible cancer cell types.

    Science.gov (United States)

    Gorjala, Priyatham; Gary, Ronald K

    2010-12-01

    In fibroblasts, beryllium salt causes activation of the p53 transcription factor and induction of a senescence-like state. It is not known whether Be(2+) can affect the proliferation of cancer cells, which are generally unsusceptible to senescence. A172 glioblastoma and RKO colon carcinoma cell lines each have wildtype p53, so these cell types have the potential to be responsive to agents that activate p53. In A172 cells, BeSO(4) produced a G(0)/G(1)-phase cell cycle arrest and increased expression of senescence-associated β-galactosidase, an enzymatic marker of senescence. BeSO(4) caused phosphorylation of serine-15 of p53, accumulation of p53 protein, and expression of p21, the cyclin-dependent kinase inhibitor that is prominent during senescence. BeSO(4) inhibited A172 growth with an IC(50) = 4.7 μM in a 6-day proliferation assay. In contrast, BeSO(4) had no effect on RKO cells, even though Be(2+) uptake was similar for the two cell types. This differential responsiveness marks BeSO(4) as a reagent capable of activating a separable branch of the p53 signaling network. A172 and RKO cells are known to exhibit p53-dependent upregulation of p21 in response to DNA damage. The RKO cells produced high levels of p21 when exposed to DNA damaging agents, yet failed to express p21 when treated with BeSO(4). Conversely, BeSO(4) did not cause DNA damage in A172 cells, yet it was a potent inducer of p21 expression. These observations indicate that the growth control pathway affected by BeSO(4) is distinct from the DNA damage response pathway, even though both ultimately converge on p53 and p21.

  4. Altered apoplastic ascorbate redox state in tobacco plants via ascorbate oxidase overexpression results in delayed dark-induced senescence in detached leaves.

    Science.gov (United States)

    Fotopoulos, Vasileios; Kanellis, Angelos K

    2013-12-01

    Ascorbate oxidase (AO) is an apoplastic enzyme that uses oxygen to catalyse the oxidation of ascorbate (AA) to dehydroascorbate (DHA) via the unstable radical monodehydroascorbate (MDHA). Here, we report that transgenic tobacco plants (Nicotiana tabacum L. cv. Xanthi) with an in vivo lowered apoplastic AA redox state through increased AO expression demonstrate signs of delayed dark-induced senescence compared with wild-type plants, as shown by chlorophyll loss assay. In situ localization of hydrogen peroxide (H2O2) suggests that, although transgenic plants have higher constitutive levels of H2O2 under normal growth conditions, imposed dark-induced senescence results in smaller induction levels of H2O2, an observation which correlates with increased antioxidant enzyme activities and an induction in the expression of AA recycling genes compared with that in wild-type plants. Our current findings, combined with previous studies which showed the contribution of AO in the regulation of AA redox state, suggest that the reduction in AA redox state in the leaf apoplast of these transgenic plants results in an increase in the endogenous levels of H2O2, which provides a form of 'acquired tolerance' to oxidative stress imposed by dark-induced senescence.

  5. MicroRNA-15b regulates mitochondrial ROS production and the senescence-associated secretory phenotype through sirtuin 4/SIRT4

    Science.gov (United States)

    Lang, Alexander; Grether-Beck, Susanne; Singh, Madhurendra; Kuck, Fabian; Jakob, Sascha; Kefalas, Andreas; Altinoluk-Hambüchen, Simone; Graffmann, Nina; Schneider, Maren; Lindecke, Antje; Brenden, Heidi; Felsner, Ingo; Ezzahoini, Hakima; Marini, Alessandra; Weinhold, Sandra; Vierkötter, Andrea; Tigges, Julia; Schmidt, Stephan; Stühler, Kai; Köhrer, Karl; Uhrberg, Markus; Haendeler, Judith; Krutmann, Jean; Piekorz, Roland P.

    2016-01-01

    Mammalian sirtuins are involved in the control of metabolism and life-span regulation. Here, we link the mitochondrial sirtuin SIRT4 with cellular senescence, skin aging, and mitochondrial dysfunction. SIRT4 expression significantly increased in human dermal fibroblasts undergoing replicative or stress-induced senescence triggered by UVB or gamma-irradiation. In-vivo, SIRT4 mRNA levels were upregulated in photoaged vs. non-photoaged human skin. Interestingly, in all models of cellular senescence and in photoaged skin, upregulation of SIRT4 expression was associated with decreased levels of miR-15b. The latter was causally linked to increased SIRT4 expression because miR-15b targets a functional binding site in the SIRT4 gene and transfection of oligonucleotides mimicking miR-15b function prevented SIRT4 upregulation in senescent cells. Importantly, increased SIRT4 negatively impacted on mitochondrial functions and contributed to the development of a senescent phenotype. Accordingly, we observed that inhibition of miR-15b, in a SIRT4-dependent manner, increased generation of mitochondrial reactive oxygen species, decreased mitochondrial membrane potential, and modulated mRNA levels of nuclear encoded mitochondrial genes and components of the senescence-associated secretory phenotype (SASP). Thus, miR-15b is a negative regulator of stress-induced SIRT4 expression thereby counteracting senescence associated mitochondrial dysfunction and regulating the SASP and possibly organ aging, such as photoaging of human skin. PMID:26959556

  6. Silymarin Suppresses Cellular Inflammation By Inducing Reparative Stress Signaling

    Energy Technology Data Exchange (ETDEWEB)

    Lovelace, Erica S.; Wagoner, Jessica; MacDonald, James; Bammler, Theo; Bruckner, Jacob; Brownell, Jessica; Beyer, Richard; Zink, Erika M.; Kim, Young-Mo; Kyle, Jennifer E.; Webb-Robertson, Bobbie-Jo M.; Waters, Katrina M.; Metz, Thomas O.; Farin, Federico; Oberlies, Nicholas H.; Polyak, Steve

    2015-08-28

    Silymarin (SM), a natural product, is touted as a liver protectant and preventer of both chronic inflammation and diseases. To define how SM elicits these effects at a systems level, we performed transcriptional profiling, metabolomics, and signaling studies in human liver and T cell lines. Multiple pathways associated with cellular stress and metabolism were modulated by SM treatment within 0.5 to four hours: activation of Activating Transcription Factor 4 (ATF-4) and adenosine monophosphate protein kinase (AMPK) and inhibition of mammalian target of rapamycin (mTOR) signaling, the latter being associated with induction of DNA-damage-inducible transcript 4 (DDIT4). Metabolomics analyses revealed suppression of glycolytic, TCA cycle, and amino acid metabolism by SM treatment. Antiinflammatory effects arose with prolonged (i.e. 24 hours) SM exposure, with suppression of multiple proinflammatory mRNAs and nuclear factor kappa B (NF-κB) and forkhead box O (FOXO) signaling. Studies with murine knock out cells revealed that SM inhibition of both mTOR and NF-κB was partially AMPK dependent, while SM inhibition of the mTOR pathway in part required DDIT4. Thus, SM activates stress and repair responses that culminate in an anti-inflammatory phenotype. Other natural products induced similar stress responses, which correlated with their ability to suppress inflammation. Therefore, natural products like SM may be useful as tools to define how metabolic, stress, and repair pathways regulate cellular inflammation.

  7. Melatonin can improve insulin resistance and aging-induced pancreas alterations in senescence-accelerated prone male mice (SAMP8)

    OpenAIRE

    Cuesta, Sara; Kireev, Roman; García, Cruz; Rancan, Lisa; Vara, Elena; Jesús A. F. Tresguerres

    2012-01-01

    The aim of the present study was to investigate the effect of aging on several parameters related to glucose homeostasis and insulin resistance in pancreas and how melatonin administration could affect these parameters. Pancreas samples were obtained from two types of male mice models: senescence-accelerated prone (SAMP8) and senescence-accelerated-resistant mice (SAMR1). Insulin levels in plasma were increased with aging in both SAMP8 and SAMR1 mice, whereas insulin content in pancreas was d...

  8. Senescence from glioma stem cell differentiation promotes tumor growth

    Energy Technology Data Exchange (ETDEWEB)

    Ouchi, Rie [Division of Molecular Biotherapy, Cancer Chemotherapy Center, Japanese Foundation for Cancer Research, 3-8-31 Ariake, Koto-ku, Tokyo 135-8550 (Japan); Laboratory of Molecular Target Therapy of Cancer, Department of Computational Biology and Medical Sciences, Graduate School of Frontier Sciences, The University of Tokyo, 3-8-31 Ariake, Koto-ku, Tokyo 135-8550 (Japan); Okabe, Sachiko; Migita, Toshiro [Division of Molecular Biotherapy, Cancer Chemotherapy Center, Japanese Foundation for Cancer Research, 3-8-31 Ariake, Koto-ku, Tokyo 135-8550 (Japan); Nakano, Ichiro [Department of Neurosurgery, Comprehensive Cancer Center, University of Alabama at Birmingham, 1824 6th Avenue South, Birmingham, AL 35233 (United States); Seimiya, Hiroyuki, E-mail: hseimiya@jfcr.or.jp [Division of Molecular Biotherapy, Cancer Chemotherapy Center, Japanese Foundation for Cancer Research, 3-8-31 Ariake, Koto-ku, Tokyo 135-8550 (Japan); Laboratory of Molecular Target Therapy of Cancer, Department of Computational Biology and Medical Sciences, Graduate School of Frontier Sciences, The University of Tokyo, 3-8-31 Ariake, Koto-ku, Tokyo 135-8550 (Japan)

    2016-02-05

    Glioblastoma (GBM) is a lethal brain tumor composed of heterogeneous cellular populations including glioma stem cells (GSCs) and differentiated non-stem glioma cells (NSGCs). While GSCs are involved in tumor initiation and propagation, NSGCs' role remains elusive. Here, we demonstrate that NSGCs undergo senescence and secrete pro-angiogenic proteins, boosting the GSC-derived tumor formation in vivo. We used a GSC model that maintains stemness in neurospheres, but loses the stemness and differentiates into NSGCs upon serum stimulation. These NSGCs downregulated telomerase, shortened telomeres, and eventually became senescent. The senescent NSGCs released pro-angiogenic proteins, including vascular endothelial growth factors and senescence-associated interleukins, such as IL-6 and IL-8. Conditioned medium from senescent NSGCs promoted proliferation of brain microvascular endothelial cells, and mixed implantation of GSCs and senescent NSGCs into mice enhanced the tumorigenic potential of GSCs. The senescent NSGCs seem to be clinically relevant, because both clinical samples and xenografts of GBM contained tumor cells that expressed the senescence markers. Our data suggest that senescent NSGCs promote malignant progression of GBM in part via paracrine effects of the secreted proteins. - Highlights: • Non-stem glioma cells (NSGCs) lose telomerase and eventually become senescent. • Senescent NSGCs secrete pro-angiogenic proteins, such as VEGFs, IL-6, and IL-8. • Senescent NSGCs enhance the growth of brain microvascular endothelial cells. • Senescent NSGCs enhance the tumorigenic potential of glioma stem cells in vivo.

  9. Yam (Dioscorea pseudojaponica Yamamoto) ameliorates cognition deficit and attenuates oxidative damage in senescent mice induced by D-galactose.

    Science.gov (United States)

    Chiu, Chuan-Sung; Deng, Jeng-Shyan; Hsieh, Ming-Tsuen; Fan, Ming-Jen; Lee, Min-Min; Chueh, Fu-Shin; Han, Chien-Kuo; Lin, Ying-Chih; Peng, Wen-Huang

    2009-01-01

    This study attempted to access the neuroprotective effect of yam (Dioscorea pseudojaponica Yamamoto) on the senescent mice induced by D-gal. The mice in the experiments were administered orally with yam (20, 100 or 500 mg/kg for 4 weeks, from the sixth week). The learning and memory abilities of the mice in Morris water maze test and the mechanisms involved in the neuroprotective effect of yam on the mice brain tissue were investigated. The content of diosgenin in the yam was also detected by using HPLC. Mice treated with yam were found to significantly improve their learning and memory abilities in Morris water maze test compared to those treated with D-gal (200 mg/kg for 10 weeks). In addition, yam was also found to increase the activities of superoxide dismutase (SOD) and glutathione peroxidase (GPx) and decrease the malondialdehyde (MDA) level on the brains of D-gal treated mice. Finally, the amount of diosgenin in the yam was 5.49 mg/g extract. To sum up, these results indicate that yam had the potential to be a useful treatment for cognitive impairment in TCM. Its beneficial effect may be partly mediated via enhancing endogenous antioxidant enzymatic activities.

  10. Induction of p21-Dependent Senescence by an NAE Inhibitor, MLN4924, as a Mechanism of Growth Suppression

    Directory of Open Access Journals (Sweden)

    Lijun Jia

    2011-06-01

    Full Text Available Cullin-RING ubiquitin ligase (CRL, with its founding member of SKP1-Cullins-F-box proteins (SCF E3 ubiquitin ligase, is the largest family of E3 ligases, which requires cullin neddylation for its activation. Recently, an inhibitor of NEDD8 activating enzyme (NAE, MLN4924, was reported to block cullin neddylation and inactivate CRL/SCF E3, resulting in apoptosis induction and tumor suppression both in vitro and in vivo. We report here that apoptosis is not the sole mechanism by which MLN4924 suppresses tumor cell growth because apoptosis is moderately induced by the drug in some cancer cell lines and drug-induced growth suppression is only partially blocked by a pan-caspase inhibitor, z-VAD. MLN4924 treatment induces the characteristics of senescence phenotypes as evidenced by enlarged and flattened cellular morphology and positive staining of senescence-associated β-Gal. MLN4924-induced senescence is associated with cellular response to DNA damage, triggered by accumulation of DNA-licensing proteins CDT1 and ORC1, as a result of inactivation of CRL/SCF E3s. The senescence occurs in the manner independent of pRB/p16 and p53, but dependent on p21, a known substrate of CRL/SCF E3s and a mediator of senescence, which accumulates on CRL/SCF inactivation by MLN4924. Furthermore, MLN4924-induced senescence is irreversible and coupled with persistent accumulation of p21 and sustained activation of DNA damage response. Our study reveals a novel mechanism of MLN4924 action and showed that MLN4924 could be further developed as an effective anticancer agent by inducing apoptosis and irreversible senescence.

  11. Expression of human telomerase (hTERT) does not prevent stress-induced senescence in normal human fibroblasts but protects the cells from stress-induced apoptosis and necrosis.

    Science.gov (United States)

    Gorbunova, Vera; Seluanov, Andrei; Pereira-Smith, Olivia M

    2002-10-11

    Cells subjected to sub-lethal doses of stress such as irradiation or oxidative damage enter a state that closely resembles replicative senescence. What triggers stress-induced premature senescence (SIPS) and how similar this mechanism is to replicative senescence are not well understood. It has been suggested that stress-induced senescence is caused by rapid telomere shortening resulting from DNA damage. In order to test this hypothesis directly, we examined whether overexpression of the catalytic subunit of human telomerase (hTERT) can protect cells from SIPS. We therefore analyzed the response of four different lines of normal human fibroblasts with and without hTERT to stress induced by UV, gamma-irradiation, and H(2)O(2). SIPS was induced with the same efficiency in normal and hTERT-immortalized cells. This suggests that SIPS is not triggered by telomere shortening and that nonspecific DNA damage serves as a signal for induction of SIPS. Although telomerase did not protect cells from SIPS, fibroblasts expressing hTERT were more resistant to stress-induced apoptosis and necrosis. We hypothesize that healing of DNA breaks by telomerase inhibits the induction of cell death, but because healing does not provide legitimate DNA repair, it does not protect cells from SIPS.

  12. Targeted Apoptosis of Senescent Cells Restores Tissue Homeostasis in Response to Chemotoxicity and Aging.

    Science.gov (United States)

    Baar, Marjolein P; Brandt, Renata M C; Putavet, Diana A; Klein, Julian D D; Derks, Kasper W J; Bourgeois, Benjamin R M; Stryeck, Sarah; Rijksen, Yvonne; van Willigenburg, Hester; Feijtel, Danny A; van der Pluijm, Ingrid; Essers, Jeroen; van Cappellen, Wiggert A; van IJcken, Wilfred F; Houtsmuller, Adriaan B; Pothof, Joris; de Bruin, Ron W F; Madl, Tobias; Hoeijmakers, Jan H J; Campisi, Judith; de Keizer, Peter L J

    2017-03-23

    The accumulation of irreparable cellular damage restricts healthspan after acute stress or natural aging. Senescent cells are thought to impair tissue function, and their genetic clearance can delay features of aging. Identifying how senescent cells avoid apoptosis allows for the prospective design of anti-senescence compounds to address whether homeostasis can also be restored. Here, we identify FOXO4 as a pivot in senescent cell viability. We designed a FOXO4 peptide that perturbs the FOXO4 interaction with p53. In senescent cells, this selectively causes p53 nuclear exclusion and cell-intrinsic apoptosis. Under conditions where it was well tolerated in vivo, this FOXO4 peptide neutralized doxorubicin-induced chemotoxicity. Moreover, it restored fitness, fur density, and renal function in both fast aging Xpd(TTD/TTD) and naturally aged mice. Thus, therapeutic targeting of senescent cells is feasible under conditions where loss of health has already occurred, and in doing so tissue homeostasis can effectively be restored. Copyright © 2017 Elsevier Inc. All rights reserved.

  13. Cold-Inducible RNA-Binding Protein Bypasses Replicative Senescence in Primary Cells through Extracellular Signal-Regulated Kinase 1 and 2 Activation▿ †

    Science.gov (United States)

    Artero-Castro, Ana; Callejas, Francisco B.; Castellvi, Josep; Kondoh, Hiroshi; Carnero, Amancio; Fernández-Marcos, Pablo J.; Serrano, Manuel; Ramón y Cajal, Santiago; Lleonart, Matilde E.

    2009-01-01

    Embryonic stem cells are immortalized cells whose proliferation rate is comparable to that of carcinogenic cells. To study the expression of embryonic stem cell genes in primary cells, genetic screening was performed by infecting mouse embryonic fibroblasts (MEFs) with a cDNA library from embryonic stem cells. Cold-inducible RNA-binding protein (CIRP) was identified due to its ability to bypass replicative senescence in primary cells. CIRP enhanced extracellular signal-regulated kinase 1 and 2 (ERK1/2) phosphorylation, and treatment with an MEK inhibitor decreased the proliferation caused by CIRP. In contrast to CIRP upregulation, CIRP downregulation decreased cell proliferation and resulted in inhibition of phosphorylated ERK1/2 inhibition. This is the first evidence that ERK1/2 activation, through the same mechanism as that described for a Val12 mutant K-ras to induce premature senescence, is able to bypass senescence in the absence of p16INK4a, p21WAF1, and p19ARF upregulation. Moreover, these results show that CIRP functions by stimulating general protein synthesis with the involvement of the S6 and 4E-BP1 proteins. The overall effect is an increase in kinase activity of the cyclin D1-CDK4 complex, which is in accordance with the proliferative capacity of CIRP MEFs. Interestingly, CIRP mRNA and protein were upregulated in a subgroup of cancer patients, a finding that may be of relevance for cancer research. PMID:19158277

  14. Cellular and Molecular Basis for Stress-Induced Depression

    Science.gov (United States)

    Seo, Ji-Seon; Wei, Jing; Qin, Luye; Kim, Yong; Yan, Zhen

    2016-01-01

    Chronic stress plays a crucial role in the development of psychiatric diseases, such as anxiety and depression. Dysfunction of the medial prefrontal cortex (mPFC) has been linked to the cognitive and emotional deficits induced by stress. However, little is known about the molecular and cellular determinants in mPFC for stress-associated mental disorders. Here we show that chronic restraint stress induces the selective loss of p11 (also known as annexin II light chain, S100A10), a multifunctional protein binding to 5-HT receptors, in layer II/III neurons of the prelimbic cortex (PrL), as well as depression-like behaviors, both of which are reversed by selective serotonin reuptake inhibitors (SSRIs) and the tricyclic class of antidepressant (TCA) agents. In layer II/III of the PrL, p11 is highly concentrated in dopamine D2 receptor-expressing (D2+) glutamatergic neurons. Viral expression of p11 in D2+ PrL neurons alleviates the depression-like behaviors exhibited by genetically manipulated mice with D2+ neuron-specific or global deletion of p11. In stressed animals, overexpression of p11 in D2+ PrL neurons rescues depression-like behaviors by restoring glutamatergic transmission. Our results have identified p11 as a key molecule in a specific cell type that regulates stress-induced depression, which provides a framework for the development of new strategies to treat stress-associated mental illnesses. PMID:27457815

  15. A human-like senescence-associated secretory phenotype is conserved in mouse cells dependent on physiological oxygen.

    Directory of Open Access Journals (Sweden)

    Jean-Philippe Coppé

    Full Text Available Cellular senescence irreversibly arrests cell proliferation in response to oncogenic stimuli. Human cells develop a senescence-associated secretory phenotype (SASP, which increases the secretion of cytokines and other factors that alter the behavior of neighboring cells. We show here that "senescent" mouse fibroblasts, which arrested growth after repeated passage under standard culture conditions (20% oxygen, do not express a human-like SASP, and differ from similarly cultured human cells in other respects. However, when cultured in physiological (3% oxygen and induced to senesce by radiation, mouse cells more closely resemble human cells, including expression of a robust SASP. We describe two new aspects of the human and mouse SASPs. First, cells from both species upregulated the expression and secretion of several matrix metalloproteinases, which comprise a conserved genomic cluster. Second, for both species, the ability to promote the growth of premalignant epithelial cells was due primarily to the conserved SASP factor CXCL-1/KC/GRO-alpha. Further, mouse fibroblasts made senescent in 3%, but not 20%, oxygen promoted epithelial tumorigenesis in mouse xenographs. Our findings underscore critical mouse-human differences in oxygen sensitivity, identify conditions to use mouse cells to model human cellular senescence, and reveal novel conserved features of the SASP.

  16. Acidosis induces reprogramming of cellular metabolism to mitigate oxidative stress

    Science.gov (United States)

    2013-01-01

    Background A variety of oncogenic and environmental factors alter tumor metabolism to serve the distinct cellular biosynthetic and bioenergetic needs present during oncogenesis. Extracellular acidosis is a common microenvironmental stress in solid tumors, but little is known about its metabolic influence, particularly when present in the absence of hypoxia. In order to characterize the extent of tumor cell metabolic adaptations to acidosis, we employed stable isotope tracers to examine how acidosis impacts glucose, glutamine, and palmitate metabolism in breast cancer cells exposed to extracellular acidosis. Results Acidosis increased both glutaminolysis and fatty acid β-oxidation, which contribute metabolic intermediates to drive the tricarboxylic acid cycle (TCA cycle) and ATP generation. Acidosis also led to a decoupling of glutaminolysis and novel glutathione (GSH) synthesis by repressing GCLC/GCLM expression. We further found that acidosis redirects glucose away from lactate production and towards the oxidative branch of the pentose phosphate pathway (PPP). These changes all serve to increase nicotinamide adenine dinucleotide phosphate (NADPH) production and counter the increase in reactive oxygen species (ROS) present under acidosis. The reduced novel GSH synthesis under acidosis may explain the increased demand for NADPH to recycle existing pools of GSH. Interestingly, acidosis also disconnected novel ribose synthesis from the oxidative PPP, seemingly to reroute PPP metabolites to the TCA cycle. Finally, we found that acidosis activates p53, which contributes to both the enhanced PPP and increased glutaminolysis, at least in part, through the induction of G6PD and GLS2 genes. Conclusions Acidosis alters the cellular metabolism of several major metabolites, which induces a significant degree of metabolic inflexibility. Cells exposed to acidosis largely rely upon mitochondrial metabolism for energy generation to the extent that metabolic intermediates are

  17. An RNA interference screen for identifying downstream effectors of the p53 and pRB tumour suppressor pathways involved in senescence

    Directory of Open Access Journals (Sweden)

    Ashworth Alan

    2011-07-01

    Full Text Available Abstract Background Cellular senescence is an irreversible cell cycle arrest that normal cells undergo in response to progressive shortening of telomeres, changes in telomeric structure, oncogene activation or oxidative stress and acts as an important tumour suppressor mechanism. Results To identify the downstream effectors of the p53-p21 and p16-pRB tumour suppressor pathways crucial for mediating entry into senescence, we have carried out a loss-of-function RNA interference screen in conditionally immortalised human fibroblasts that can be induced to rapidly undergo senescence, whereas in primary cultures senescence is stochastic and occurs asynchronously. These cells are immortal but undergo a rapid irreversible arrest upon activation of the p53-p21 and p16-pRB pathways that can be readily bypassed upon their inactivation. The primary screen identified 112 known genes including p53 and another 29 shRNAmirs targetting as yet unidentified loci. Comparison of these known targets with genes known to be up-regulated upon senescence in these cells, by micro-array expression profiling, identified 4 common genes TMEM9B, ATXN10, LAYN and LTBP2/3. Direct silencing of these common genes, using lentiviral shRNAmirs, bypassed senescence in the conditionally immortalised cells. Conclusion The senescence bypass screen identified TMEM9B, ATXN10, LAYN and LTBP2/3 as novel downstream effectors of the p53-p21 and p16-pRB tumour suppressor pathways. Although none of them has previously been linked to cellular senescence, TMEM9B has been suggested to be an upstream activator of NF-κB signalling which has been found to have a causal role in promoting senescence. Future studies will focus on determining on how many of the other primary hits also have a casual role in senescence and what is the mechanism of action.

  18. Ablation of XP-V gene causes adipose tissue senescence and metabolic abnormalities.

    Science.gov (United States)

    Chen, Yih-Wen; Harris, Robert A; Hatahet, Zafer; Chou, Kai-ming

    2015-08-18

    Obesity and the metabolic syndrome have evolved to be major health issues throughout the world. Whether loss of genome integrity contributes to this epidemic is an open question. DNA polymerase η (pol η), encoded by the xeroderma pigmentosum (XP-V) gene, plays an essential role in preventing cutaneous cancer caused by UV radiation-induced DNA damage. Herein, we demonstrate that pol η deficiency in mice (pol η(-/-)) causes obesity with visceral fat accumulation, hepatic steatosis, hyperleptinemia, hyperinsulinemia, and glucose intolerance. In comparison to WT mice, adipose tissue from pol η(-/-) mice exhibits increased DNA damage and a greater DNA damage response, indicated by up-regulation and/or phosphorylation of ataxia telangiectasia mutated (ATM), phosphorylated H2AX (γH2AX), and poly[ADP-ribose] polymerase 1 (PARP-1). Concomitantly, increased cellular senescence in the adipose tissue from pol η(-/-) mice was observed and measured by up-regulation of senescence markers, including p53, p16(Ink4a), p21, senescence-associated (SA) β-gal activity, and SA secretion of proinflammatory cytokines interleukin 6 (IL-6) and tumor necrosis factor α (TNF-α) as early as 4 wk of age. Treatment of pol η(-/-) mice with a p53 inhibitor, pifithrin-α, reduced adipocyte senescence and attenuated the metabolic abnormalities. Furthermore, elevation of adipocyte DNA damage with a high-fat diet or sodium arsenite exacerbated adipocyte senescence and metabolic abnormalities in pol η(-/-) mice. In contrast, reduction of adipose DNA damage with N-acetylcysteine or metformin ameliorated cellular senescence and metabolic abnormalities. These studies indicate that elevated DNA damage is a root cause of adipocyte senescence, which plays a determining role in the development of obesity and insulin resistance.

  19. Ethanol-Induced Cerebellar Ataxia: Cellular and Molecular Mechanisms.

    Science.gov (United States)

    Dar, M Saeed

    2015-08-01

    The cerebellum is an important target of ethanol toxicity given that cerebellar ataxia is the most consistent physical manifestation of acute ethanol consumption. Despite the significance of the cerebellum in ethanol-induced cerebellar ataxia (EICA), the cellular and molecular mechanisms underlying EICA are incompletely understood. However, two important findings have shed greater light on this phenomenon. First, ethanol-induced blockade of cerebellar adenosine uptake in rodent models points to a role for adenosinergic A1 modulation of EICA. Second, the consistent observation that intracerebellar administration of nicotine in mice leads to antagonism of EICA provides evidence for a critical role of cerebellar nitric oxide (NO) in EICA reversal. Based on these two important findings, this review discusses the potential molecular events at two key synaptic sites (mossy fiber-granule cell-Golgi cell (MGG synaptic site) and granule cell parallel fiber-Purkinje cell (GPP synaptic site) that lead to EICA. Specifically, ethanol-induced neuronal NOS inhibition at the MGG synaptic site acts as a critical trigger for Golgi cell activation which leads to granule cell deafferentation. Concurrently, ethanol-induced inhibition of adenosine uptake at the GPP synaptic site produces adenosine accumulation which decreases glutamate release and leads to the profound activation of Purkinje cells (PCs). These molecular events at the MGG and GPP synaptic sites are mutually reinforcing and lead to cerebellar dysfunction, decreased excitatory output of deep cerebellar nuclei, and EICA. The critical importance of PCs as the sole output of the cerebellar cortex suggests normalization of PC function could have important therapeutic implications.

  20. Preventive Effects of Epigallocatechin-3-O-Gallate against Replicative Senescence Associated with p53 Acetylation in Human Dermal Fibroblasts

    Directory of Open Access Journals (Sweden)

    Dong-Wook Han

    2012-01-01

    Full Text Available Considering the various pharmacological activities of epigallocatechin-3-O-gallate (EGCG including anticancer, and anti-inflammatory, antidiabetic, and so forth, relatively less attention has been paid to the antiaging effect of EGCG on primary cells. In this study, the preventive effects of EGCG against serial passage-induced senescence were investigated in primary cells including rat vascular smooth muscle cells (RVSMCs, human dermal fibroblasts (HDFs, and human articular chondrocytes (HACs. The involvement of Sirt1 and acetylated p53 was examined as an underlying mechanism for the senescence preventive activity of EGCG in HDFs. All cells were employed with the initial passage number (PN between 3 and 7. For inducing senescence, the cells were serially passaged at the predetermined times and intervals in the absence or presence of EGCG (50 or 100 μM. Serial passage-induced senescence in RVSMCs and HACs was able to be significantly prevented at 50 μM EGCG, while in HDFs, 100 μM EGCG could significantly prevent senescence and recover their cell cycle progression close to the normal level. Furthermore, EGCG was found to prevent serial passage- and H2O2-induced senescence in HDFs by suppressing p53 acetylation, but the Sirt1 activity was unaffected. In addition, proliferating HDFs showed similar cellular uptake of FITC-conjugated EGCG into the cytoplasm with their senescent counterparts but different nuclear translocation of it from them, which would partly account for the differential responses to EGCG in proliferating versus senescent cells. Taking these results into consideration, it is suggested that EGCG may be exploited to craft strategies for the development of an antiaging or age-delaying agent.

  1. HDACs and the senescent phenotype of WI-38 cells

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    Noonan Emily J

    2005-10-01

    Full Text Available Abstract Background Normal cells possess a limited proliferative life span after which they enter a state of irreversible growth arrest. This process, known as replicative senescence, is accompanied by changes in gene expression that give rise to a variety of senescence-associated phenotypes. It has been suggested that these gene expression changes result in part from alterations in the histone acetylation machinery. Here we examine the influence of HDAC inhibitors on the expression of senescent markers in pre- and post-senescent WI-38 cells. Results Pre- and post-senescent WI-38 cells were treated with the HDAC inhibitors butyrate or trichostatin A (TSA. Following HDAC inhibitor treatment, pre-senescent cells increased p21WAF1 and β-galactosidase expression, assumed a flattened senescence-associated morphology, and maintained a lower level of proteasome activity. These alterations also occurred during normal replicative senescence of WI-38 cells, but were not accentuated further by HDAC inhibitors. We also found that HDAC1 levels decline during normal replicative senescence. Conclusion Our findings indicate that HDACs impact numerous phenotypic changes associated with cellular senescence. Reduced HDAC1 expression levels in senescent cells may be an important event in mediating the transition to a senescent phenotype.

  2. Mapping QTL for drought stress-induced premature senescence and maturity in cowpea [Vigna unguiculata (L.) Walp.].

    Science.gov (United States)

    Muchero, Wellington; Ehlers, Jeffrey D; Close, Timothy J; Roberts, Philip A

    2009-03-01

    Cowpea is an important crop for subsistence farmers in arid regions of Africa, Asia, and South America. Efforts to develop cultivars with improved productivity under drought conditions are constrained by lack of molecular markers associated with drought tolerance. Here, we report the mapping of 12 quantitative trait loci (QTL) associated with seedling drought tolerance and maturity in a cowpea recombinant inbred (RIL) population. One hundred and twenty-seven F(8) RILs developed from a cross between IT93K503-1 and CB46 were screened with 62 EcoR1 and Mse1 primer combinations to generate 306 amplified fragment length polymorphisms for use in genetic linkage mapping. The same population was phenotyped for maintenance of stem greenness (stg) and recovery dry weight (rdw) after drought stress in six greenhouse experiments. In field experiments conducted over 3 years, visual ratings and dry weights were used to phenotype drought stress-induced premature senescence in the RIL population. Kruskall-Wallis and multiple-QTL model mapping analysis were used to identify QTL associated with drought response phenotypes. Observed QTL were highly reproducible between stg and rdw under greenhouse conditions. Field studies confirmed all ten drought-response QTL observed under greenhouse conditions. Regions harboring drought-related QTL were observed on linkage groups 1, 2, 3, 5, 6, 7, 9, and 10 accounting for between 4.7 and 24.2% of the phenotypic variance (R(2)). Further, two QTL for maturity (R(2) = 14.4-28.9% and R(2) = 11.7-25.2%) mapped on linkage groups 7 and 8 separately from drought-related QTL. These results provide a platform for identification of genetic determinants of seedling drought tolerance in cowpea.

  3. Senescence-Induced Alterations in the Laminin Component of Prostate Epithelial Extracellular Matrix Regulate Progression of Prostate Cancer

    Science.gov (United States)

    2009-01-01

    this to be especially relevant to the senescence process. Since many chemotherapeutic agents act through induction of a senescence process, this work...tumours (Reed et al, 2007). The therapeutic implications are especially of interest in the treatment of cancers that produce large quantities of collagen...full-length LMα4 chain (LAMA4) cDNA was ob- tained from OriGene (Rockville, MD) in their nonselectable vector (pCMV6-XL4). We subcloned the LAMA4 cDNA

  4. Senescing cells share common features with dedifferentiating cells.

    Science.gov (United States)

    Damri, Meytal; Granot, Gila; Ben-Meir, Hagit; Avivi, Yigal; Plaschkes, Inbar; Chalifa-Caspi, Vered; Wolfson, Marina; Fraifeld, Vadim; Grafi, Gideon

    2009-12-01

    Dedifferentiation signifies the capacity of somatic cells to acquire stem cell-like properties. This process can be induced during normal development and as a response to various stimuli, such as pathogen infection and wounding. Dedifferentiation also characterizes the transition of differentiated leaf cells into protoplasts (plant cells devoid of cell walls), a transition accompanied by widespread chromatin decondensation. Transcriptome profiling of dedifferentiating protoplast cells revealed striking similarities with senescing cells; both display a large increase in the expression of genes of specific transcription factor (TF) families, including ANAC, WRKY, bZIP, and C2H2. Further analysis showed that leaves induced to senesce by exposure to dark display characteristic features of dedifferentiating cells, including chromatin decondensation, disruption of the nucleolus, and condensation of rRNA genes. Considering that premature senescence can be induced by various stress conditions both in plant and animal cells, our results suggest that the response of plant and also animal cells to certain stresses converges on cellular dedifferentiation whereby cells first acquire stem cell-like state prior to acquisition of a new cell fate (e.g., reentry into the cell cycle or death).

  5. Induction of senescence and identification of differentially expressed genes in tomato in response to monoterpene.

    Directory of Open Access Journals (Sweden)

    Sumit Ghosh

    Full Text Available Monoterpenes, which are among the major components of plant essential oils, are known for their ecological roles as well for pharmaceutical properties. Geraniol, an acyclic monoterpene induces cell cycle arrest and apoptosis/senescence in various cancer cells and plants; however, the genes involved in the process and the underlying molecular mechanisms are not well understood. In this study, we demonstrate that treatment of tomato plants with geraniol results in induction of senescence due to a substantial alteration in transcriptome. We have identified several geraniol-responsive protein encoding genes in tomato using suppression subtractive hybridization (SSH approach. These genes comprise of various components of signal transduction, cellular metabolism, reactive oxygen species (ROS, ethylene signalling, apoptosis and DNA damage response. Upregulation of NADPH oxidase and antioxidant genes, and increase in ROS level after geraniol treatment point towards the involvement of ROS in geraniol-mediated senescence. The delayed onset of seedling death and induced expression of geraniol-responsive genes in geraniol-treated ethylene receptor mutant (Nr suggest that geraniol-mediated senescence involves both ethylene dependent and independent pathways. Moreover, expression analysis during tomato ripening revealed that geraniol-responsive genes are also associated with the natural organ senescence process.

  6. mTOR inactivation by ROS-JNK-p53 pathway plays an essential role in psedolaric acid B induced autophagy-dependent senescence in murine fibrosarcoma L929 cells.

    Science.gov (United States)

    Qi, Min; Zhou, Haiyan; Fan, Simiao; Li, Zhao; Yao, Guodong; Tashiro, Shin-Ichi; Onodera, Satoshi; Xia, Mingyu; Ikejima, Takashi

    2013-09-05

    Pseudolaric acid B (PAB), the primary biologically active compound isolated from the root bark of P. kaempferi Gordon, has been reported to exhibit anti-tumor effect primarily via cell cycle arrest and apoptosis. Our previous study demonstrated that PAB triggered mitotic catastrophe in L929 cells. In addition, a small percentage of the cells undergoing mitotic catastrophe displayed an apoptotic phenotype. Therefore, we continued to investigate the fate of the other cells. The results indicated that PAB induced senescence through p19-p53-p21 and p16-Rb pathways in L929 cells. PAB also triggered autophagy via inhibiting Akt-mammalian target of rapamycin (mTOR) activity in L929 cells. In addition, autophagy was demonstrated to reinforce senescence through regulating the senescence pathways. Thus, we focused on the detailed molecular mechanisms whereby autophagy promoted senescence. Reactive oxygen species (ROS) plays an important in autophagy and senescence. We found that PAB triggered a ROS-JNK-p53 positive feedback loop and this feedback loop played a crucial role in autophagy via repressing the activation of mTOR. Furthermore, ROS-JNK-p53 positive feedback loop was demonstrated to regulate senescence. Tuberous sclerosis proteins1 and 2, also known as TSC1 and TSC2, form a protein-complex. TSC1/TSC2 heterodimer is a downstream target of growth factor-phosphoinositide 3-kinase-Akt signaling which negatively regulates mTOR activity. Activation of mTOR by insulin or inhibition of endogenous TSC2 levels by siRNA obviously delayed PAB-induced senescence. In conclusion, mTOR inactivation by ROS-JNK-p53 pathway played an important role in autophagy-dependent senescence in PAB-treated L929 cells.

  7. Intranasal Cerebrolysin Attenuates Learning and Memory Impairments in D-galactose-Induced Senescence in Mice.

    Science.gov (United States)

    Pourmemar, Ehsan; Majdi, Alireza; Haramshahi, Morteza; Talebi, Mahnaz; Karimi, Pouran; Sadigh-Eteghad, Saeed

    2017-01-01

    Neurotrophic factors are currently being considered as pro-cognitive therapeutic approaches for management of cognitive deficits. This study aims to evaluate the effects of intranasal (i.n.) or intraperitoneal (i.p.) administration of Cerebrolysin (CBL) (as a mixture of neurotrophic factors) on the d-galactose-induced oxidative stress, apoptosis and memory as well as learning impairment in mice. For this purpose, CBL (1, 2.5, 5 ml/kg/i.p.) or (1 ml/kg/i.n.), were administrated daily in d-galactose-received (100 mg/kg/subcutaneous (s.c.)) mice model of aging for eight weeks. Spatial and recognition memories were assessed by the Morris water maze and novel object recognition tasks. Brain and blood of animals were analysed for oxidative stress biomarkers including malondialdehyde, total antioxidant capacity, glutathione peroxidase and superoxide dismutase. Apoptosis rate in the hippocampus was evaluated by TUNEL staining of brain tissue. 5 ml/kg/i.p. dose of CBL increased the locomotor activity but, 1 ml/kg/i.p. dose didn't show detectable behavioural or molecular effects on aged mice. Treatment with 2.5 ml/kg/i.p. and 1 ml/kg/i.n. doses attenuated d-galactose-impaired spatial and recognition memories. Results showed an obvious increase in the antioxidant biomarkers and decrease in the malondialdehyde levels both in the blood and brain of aged mice in 2.5 ml/kg/i.p. dose, and only in the brain in 1 ml/kg/i.n. dose of CBL. Anti-apoptotic effects also were seen in the same dose/rout of CBL administration in aged animals. This study proves the usefulness of i.n. CBL administration as a non-invasive and efficient method of drug delivery to the brain to improve aging-induced oxidative stress, apoptosis and learning as well as memory impairment.

  8. Differential Impact of Lipoxygenase 2 and Jasmonates on Natural and Stress-Induced Senescence in Arabidopsis1[W

    Science.gov (United States)

    Seltmann, Martin A.; Stingl, Nadja E.; Lautenschlaeger, Jens K.; Krischke, Markus; Mueller, Martin J.; Berger, Susanne

    2010-01-01

    Jasmonic acid and related oxylipins are controversially discussed to be involved in regulating the initiation and progression of leaf senescence. To this end, we analyzed profiles of free and esterified oxylipins during natural senescence and upon induction of senescence-like phenotypes by dark treatment and flotation on sorbitol in Arabidopsis (Arabidopsis thaliana). Jasmonic acid and free 12-oxo-phytodienoic acid increased during all three processes, with the strongest increase of jasmonic acid after dark treatment. Arabidopside content only increased considerably in response to sorbitol treatment. Monogalactosyldiacylglycerols and digalactosyldiacylglycerols decreased during these treatments and aging. Lipoxygenase 2-RNA interference (RNAi) plants were generated, which constitutively produce jasmonic acid and 12-oxo-phytodienoic acid but do not exhibit accumulation during natural senescence or upon stress treatment. Chlorophyll loss during aging and upon dark incubation was not altered, suggesting that these oxylipins are not involved in these processes. In contrast, lipoxygenase 2-RNAi lines and the allene oxid synthase-deficient mutant dde2 were less sensitive to sorbitol than the wild type, indicating that oxylipins contribute to the response to sorbitol stress. PMID:20190093

  9. p53-independent upregulation of miR-34a during oncogene-induced senescence represses MYC

    DEFF Research Database (Denmark)

    Christoffersen, N R; Shalgi, R; Frankel, L B

    2010-01-01

    , upregulation of miR-34a is mediated by the ETS family transcription factor, ELK1. During senescence, miR-34a targets the important proto-oncogene MYC and our data suggest that miR-34a thereby coordinately controls a set of cell cycle regulators. Hence, in addition to its integration in the p53 pathway, we show...

  10. Persistent DNA damage-induced premature senescence alters the functional features of human bone marrow mesenchymal stem cells.

    Science.gov (United States)

    Minieri, Valentina; Saviozzi, Silvia; Gambarotta, Giovanna; Lo Iacono, Marco; Accomasso, Lisa; Cibrario Rocchietti, Elisa; Gallina, Clara; Turinetto, Valentina; Giachino, Claudia

    2015-04-01

    Human mesenchymal stem cells (hMSCs) are adult multipotent stem cells located in various tissues, including the bone marrow. In contrast to terminally differentiated somatic cells, adult stem cells must persist and function throughout life to ensure tissue homeostasis and repair. For this reason, they must be equipped with DNA damage responses able to maintain genomic integrity while ensuring their lifelong persistence. Evaluation of hMSC response to genotoxic insults is of great interest considering both their therapeutic potential and their physiological functions. This study aimed to investigate the response of human bone marrow MSCs to the genotoxic agent Actinomycin D (ActD), a well-known anti-tumour drug. We report that hMSCs react by undergoing premature senescence driven by a persistent DNA damage response activation, as hallmarked by inhibition of DNA synthesis, p21 and p16 protein expression, marked Senescent Associated β-galactosidase activity and enlarged γH2AX foci co-localizing with 53BP1 protein. Senescent hMSCs overexpress several senescence-associated secretory phenotype (SASP) genes and promote motility of lung tumour and osteosarcoma cell lines in vitro. Our findings disclose a multifaceted consequence of ActD treatment on hMSCs that on the one hand helps to preserve this stem cell pool and prevents damaged cells from undergoing neoplastic transformation, and on the other hand alters their functional effects on the surrounding tissue microenvironment in a way that might worsen their tumour-promoting behaviour.

  11. In Caenorhabditis elegans nanoparticle-bio-interactions become transparent: silica-nanoparticles induce reproductive senescence.

    Directory of Open Access Journals (Sweden)

    Adam Pluskota

    Full Text Available While expectations and applications of nanotechnologies grow exponentially, little is known about interactions of engineered nanoparticles with multicellular organisms. Here we propose the transparent roundworm Caenorhabditis elegans as a simple but anatomically and biologically well defined animal model that allows for whole organism analyses of nanoparticle-bio-interactions. Microscopic techniques showed that fluorescently labelled nanoparticles are efficiently taken up by the worms during feeding, and translocate to primary organs such as epithelial cells of the intestine, as well as secondary organs belonging to the reproductive tract. The life span of nanoparticle-fed Caenorhabditis elegans remained unchanged, whereas a reduction of progeny production was observed in silica-nanoparticle exposed worms versus untreated controls. This reduction was accompanied by a significant increase of the 'bag of worms' phenotype that is characterized by failed egg-laying and usually occurs in aged wild type worms. Experimental exclusion of developmental defects suggests that silica-nanoparticles induce an age-related degeneration of reproductive organs, and thus set a research platform for both, detailed elucidation of molecular mechanisms and high throughput screening of different nanomaterials by analyses of progeny production.

  12. Cytosolic malate dehydrogenase regulates senescence in human fibroblasts.

    Science.gov (United States)

    Lee, Seung-Min; Dho, So Hee; Ju, Sung-Kyu; Maeng, Jin-Soo; Kim, Jeong-Yoon; Kwon, Ki-Sun

    2012-10-01

    Carbohydrate metabolism changes during cellular senescence. Cytosolic malate dehydrogenase (MDH1) catalyzes the reversible reduction of oxaloacetate to malate at the expense of reduced nicotinamide adenine dinucleotide (NADH). Here, we show that MDH1 plays a critical role in the cellular senescence of human fibroblasts. We observed that the activity of MDH1 was reduced in old human dermal fibroblasts (HDFs) [population doublings (PD) 56], suggesting a link between decreased MDH1 protein levels and aging. Knockdown of MDH1 in young HDFs (PD 20) and the IMR90 human fibroblast cell line resulted in the appearance of significant cellular senescence features, including senescence-associated β-galactosidase staining, flattened and enlarged morphology, increased population doubling time, and elevated p16(INK4A) and p21(CIP1) protein levels. Cytosolic NAD/NADH ratios were decreased in old HDFs to the same extent as in MDH1 knockdown HDFs, suggesting that cytosolic NAD depletion is related to cellular senescence. We found that AMP-activated protein kinase, a sensor of cellular energy, was activated in MDH1 knockdown cells. We also found that sirtuin 1 (SIRT1) deacetylase, a controller of cellular senescence, was decreased in MDH1 knockdown cells. These results indicate that the decrease in MDH1 and subsequent reduction in NAD/NADH ratio, which causes SIRT1 inhibition, is a likely carbohydrate metabolism-controlled cellular senescence mechanism.

  13. SENESCENCE-SUPPRESSED PROTEIN PHOSPHA