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Zhang M, Li L, Wang Z, Liu H, Hou J, Zhang M, Hao A, Liu Y, He G, Shi Y, He L, Wang X, Wan Y, Li B. A role for c-Abl in cell senescence and spontaneous immortalization. AGE (DORDRECHT, NETHERLANDS) 2013; 35:1251-1262. [PMID: 22791394 PMCID: PMC3705115 DOI: 10.1007/s11357-012-9452-4] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/08/2011] [Accepted: 06/27/2012] [Indexed: 06/01/2023]
Abstract
c-Abl is a proto-oncogene that is essential for mouse development and tissue homeostasis. Misregulation of c-Abl, as seen in the constitutively active BCR-ABL, is the leading cause of human chronic myeloid leukemia. However, how the Abl proteins execute their functions still remains largely unknown. Here, we report an important role for c-Abl in replicative senescence and immortalization by regulating the expression of two tumor suppressors that induce cellular senescence, p53 and p16(INK4a). Using primary mouse embryonic fibroblasts (MEFs), we show that c-Abl (-/-) cells were more resistant to immortalization than wildtype cells using a standard 3T3 or 3T9 protocol. We could only immortalize three out of nine c-Abl (-/-) MEF cultures even when we increased the number of starting cells. This resistance was attributed to premature senescence and reduced survival in senescent c-Abl (-/-) cells due to an increase in p16(INK4a) and p53 expression. Deleting p53 allows c-Abl (-/-) p53 (-/-) MEFs to bypass senescence to be spontaneously immortalized. Cell immortalization, but not senescence, was generally accompanied by mutations in p53 in both wildtype and c-Abl (-/-) MEFs, although the spectrum is different from that of human tumors. The role for c-Abl in regulating cell senescence and immortalization might explain some of the developmental defects in c-Abl (-/-) mice and how BCR-ABL transforms cells.
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Affiliation(s)
- Man Zhang
- />Department of Clinical Laboratory, Beijing Shi Ji Tan Hospital, Capital Medical University, Beijing, People’s Republic of China
| | - Lili Li
- />Bio-X Institutes, Key Laboratory for the Genetics of Developmental and Neuropsychiatric Disorders, Ministry of Education, Shanghai Jiao Tong University, Shanghai, People’s Republic of China
- />Key Laboratory of the Ministry of Education for Experimental Teratology, Shandong University School of Medicine, Jinan, People’s Republic of China
| | - Zhongfeng Wang
- />Bio-X Institutes, Key Laboratory for the Genetics of Developmental and Neuropsychiatric Disorders, Ministry of Education, Shanghai Jiao Tong University, Shanghai, People’s Republic of China
| | - Huijuan Liu
- />Bio-X Institutes, Key Laboratory for the Genetics of Developmental and Neuropsychiatric Disorders, Ministry of Education, Shanghai Jiao Tong University, Shanghai, People’s Republic of China
| | - Junlin Hou
- />Department of Clinical Laboratory, Beijing Shi Ji Tan Hospital, Capital Medical University, Beijing, People’s Republic of China
| | - Min Zhang
- />Department of Clinical Laboratory, Beijing Shi Ji Tan Hospital, Capital Medical University, Beijing, People’s Republic of China
| | - Aijun Hao
- />Key Laboratory of the Ministry of Education for Experimental Teratology, Shandong University School of Medicine, Jinan, People’s Republic of China
| | - Yun Liu
- />Institutes of Biomedical Sciences, Fudan University, Shanghai, People’s Republic of China
| | - Guang He
- />Bio-X Institutes, Key Laboratory for the Genetics of Developmental and Neuropsychiatric Disorders, Ministry of Education, Shanghai Jiao Tong University, Shanghai, People’s Republic of China
| | - Yongyong Shi
- />Bio-X Institutes, Key Laboratory for the Genetics of Developmental and Neuropsychiatric Disorders, Ministry of Education, Shanghai Jiao Tong University, Shanghai, People’s Republic of China
| | - Lin He
- />Bio-X Institutes, Key Laboratory for the Genetics of Developmental and Neuropsychiatric Disorders, Ministry of Education, Shanghai Jiao Tong University, Shanghai, People’s Republic of China
| | - Xueying Wang
- />Department of Biochemistry, Yong Loo Lin School of Medicine, Cancer Science Institute of Singapore, MD7, 8 Medical Drive, Singapore, 117597 Singapore
| | - Yue Wan
- />Howard Hughes Medical Institute and Program in Epithelial Biology, Stanford University School of Medicine, Stanford, CA 94305 USA
| | - Baojie Li
- />Bio-X Institutes, Key Laboratory for the Genetics of Developmental and Neuropsychiatric Disorders, Ministry of Education, Shanghai Jiao Tong University, Shanghai, People’s Republic of China
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152
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Zhao C, Feng B, Cao Y, Xie P, Xu J, Pang Y, Liu X, Li Q. Identification and characterisation of ROS modulator 1 in Lampetra japonica. FISH & SHELLFISH IMMUNOLOGY 2013; 35:278-283. [PMID: 23685010 DOI: 10.1016/j.fsi.2013.04.039] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/15/2012] [Revised: 04/22/2013] [Accepted: 04/22/2013] [Indexed: 06/02/2023]
Abstract
Reactive oxygen species (ROS) are a heterogeneous group of highly reactive molecules that oxidise targets in biological systems. ROS are also considered important immune regulators. In this study, we identified a homologue of reactive oxygen species modulator 1 (Romo1) in the Japanese lamprey (Lampetra japonica). The L japonica Romo1 (Lj-Romo1) gene shares high sequence homology with the Romo1 genes of jawed vertebrates. Real-time quantitative PCR demonstrated the wide distribution of Lj-Romo1 in lamprey tissues. Furthermore, after the lampreys were stimulated with lipopolysaccharide (LPS), the level of Lj-Romo1 mRNA was markedly up-regulated in the liver, gill, kidney, and intestine tissues. Lj-Romo1 was localised to the mitochondria and has the capacity to increase the ROS level in cells. The results obtained in the present study will help us to understand the roles of Romo1 in ROS production and innate immune responses in jawless vertebrates.
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Affiliation(s)
- Chunhui Zhao
- Liaoning Provincial Key Laboratory of Biotechnology and Drug Discovery, Faculty of Life Science, Liaoning Normal University, Dalian 116081, China
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153
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Abstract
Telomere shortening is emerging as a biological indicator of accelerated aging and aging-related diseases including type 2 diabetes. While telomere length measurements were largely done in white blood cells, there is lack of studies on telomere length in relation to oxidative stress in target tissues affected in diabetes. Therefore, the aim of this study is to induct oxidative stress in adipocytes and to test whether these adipocytes exhibit shortened telomeres, senescence and functional impairment. 3T3-L1 adipocytes were subjected to oxidative stress and senescence induction by a variety of means for 2 weeks (exogenous application of H2O2, glucose oxidase, asymmetric dimethylarginine (ADMA) and glucose oscillations). Cells were probed for reactive oxygen species generation (ROS), DNA damage, mRNA and protein expression of senescent and pro-inflammatory markers, telomere length and glucose uptake. Compared to untreated cells, both ROS generation and DNA damage were significantly higher in cells subjected to oxidative stress and senescence. Adipocytes subjected to oxidative stress also showed shortened telomeres and increased mRNA and protein expression of p53, p21, TNF alpha and IL-6. Senescent cells were also characterized by decreased levels of adiponectin and impaired glucose uptake. Briefly, adipocytes under oxidative stress exhibited increased ROS generation, DNA damage, shortened telomeres and switched to senescent/pro-inflammatory phenotype with impaired glucose uptake.
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154
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Tung BT, Rodríguez-Bies E, Ballesteros-Simarro M, Motilva V, Navas P, López-Lluch G. Modulation of endogenous antioxidant activity by resveratrol and exercise in mouse liver is age dependent. J Gerontol A Biol Sci Med Sci 2013; 69:398-409. [PMID: 23861386 DOI: 10.1093/gerona/glt102] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
UNLABELLED Aging is a multifactorial process in which oxidative damage plays an important role. Resveratrol (RSV) and exercise delay some of the damages occurring during aging and increase life span and health span. We treated mice at different ages with RSV during 6 months and trained them during the last 6 weeks to determine if RSV and exercise induce changes in endogenous antioxidant activities in liver and if their effects depend on the age of the animal at the beginning of the intervention. Aging was accompanied by the increase in oxidative damage in liver especially affecting the glutathione-dependent system. Both RSV and exercise reversed the effect of aging and maintained high activities of glutathione, glutathione peroxidase, and glutathione transferase activities in old animals. NAD(P)H quinone acceptor oxidoreductase activity was also increased. Modulation of antioxidant activities was not completely accompanied by changes at the protein level. Whereas glutathione peroxidase 1 protein increased in parallel to the higher activity in old animals, NAD(P)H quinone acceptor oxidoreductase protein decreased by RSV although the activity was enhanced. Our results indicate that RSV and exercise revert the effect of aging in liver of old animals maintaining higher antioxidant activities and decreasing oxidative damage. Short-term interventions are enough to produce beneficial effects of RSV or exercise at later ages.
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Affiliation(s)
- Bui Thanh Tung
- Centro Andaluz de Biología del Desarrollo, Universidad Pablo de Olavide, Carretera de Utrera Km. 1, 41013 Sevilla, Spain.
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155
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Perrone CE, Malloy VL, Orentreich DS, Orentreich N. Metabolic adaptations to methionine restriction that benefit health and lifespan in rodents. Exp Gerontol 2013; 48:654-60. [DOI: 10.1016/j.exger.2012.07.005] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2012] [Revised: 07/09/2012] [Accepted: 07/10/2012] [Indexed: 01/05/2023]
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156
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Choi J, Park SJ, Jo EJ, Lee HY, Hong S, Kim SJ, Kim BC. Hydrogen peroxide inhibits transforming growth factor-β1-induced cell cycle arrest by promoting Smad3 linker phosphorylation through activation of Akt-ERK1/2-linked signaling pathway. Biochem Biophys Res Commun 2013; 435:634-9. [PMID: 23685151 DOI: 10.1016/j.bbrc.2013.05.035] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2013] [Accepted: 05/08/2013] [Indexed: 01/07/2023]
Abstract
Hydrogen peroxide (H2O2) functions as a second messenger in growth factor receptor-mediated intracellular signaling cascade and is tumorigenic by virtue of its ability to promote cell proliferation; however, the mechanisms underlying the growth stimulatory action of H2O2 are less understood. Here we report an important mechanism for antagonistic effects of H2O2 on growth inhibitory response to transforming growth factor-β1 (TGF-β1). In Mv1Lu and HepG2 cells, pretreatment of H2O2 (0.05-0.2 mM) completely blocked TGF-β1-mediated induction of p15(INK4B) expression and increase of its promoter activity. Interestingly, H2O2 selectively suppressed the transcriptional activation potential of Smad3, not Smad2, in the absence of effects on TGF-β1-induced phosphorylation of the COOH-tail SSXS motif of Smad3 and its nuclear translocation. Mechanism studies showed that H2O2 increases the phosphorylation of Smad3 at the middle linker region in a concentration- and time-dependent manner and this effect is mediated by activation of extracellular signal-activated kinase 1/2 through Akt. Furthermore, expression of a mutant Smad3 in which linker phosphorylation sites were ablated significantly abrogated the inhibitory effects of H2O2 on TGF-β1-induced increase of p15(INK4B)-Luc reporter activity and blockade of cell cycle progression from G1 to S phase. These findings for the first time define H2O2 as a signaling molecule that modulate Smad3 linker phosphorylation and its transcriptional activity, thus providing a potential mechanism whereby H2O2 antagonizes the cytostatic function of TGF-β1.
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Affiliation(s)
- Jiyeon Choi
- Department of Biochemistry, College of Natural Sciences, Kangwon National University, Chuncheon 200-701, Republic of Korea
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157
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Ohtsuka H, Ogawa S, Kawamura H, Sakai E, Ichinose K, Murakami H, Aiba H. Screening for long-lived genes identifies Oga1, a guanine-quadruplex associated protein that affects the chronological lifespan of the fission yeast Schizosaccharomyces pombe. Mol Genet Genomics 2013; 288:285-95. [DOI: 10.1007/s00438-013-0748-6] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2012] [Accepted: 04/19/2013] [Indexed: 12/31/2022]
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158
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Aan GJ, Zainudin MSA, Karim NA, Ngah WZW. Effect of the tocotrienol-rich fraction on the lifespan and oxidative biomarkers in Caenorhabditis elegans under oxidative stress. Clinics (Sao Paulo) 2013; 68:599-604. [PMID: 23778402 PMCID: PMC3654308 DOI: 10.6061/clinics/2013(05)04] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/05/2012] [Revised: 12/02/2012] [Accepted: 01/04/2013] [Indexed: 01/10/2023] Open
Abstract
OBJECTIVE This study was performed to determine the effect of the tocotrienol-rich fraction on the lifespan and oxidative status of C. elegans under oxidative stress. METHOD Lifespan was determined by counting the number of surviving nematodes daily under a dissecting microscope after treatment with hydrogen peroxide and the tocotrienol-rich fraction. The evaluated oxidative markers included lipofuscin, which was measured using a fluorescent microscope, and protein carbonyl and 8-hydroxy-2'-deoxyguanosine, which were measured using commercially available kits. RESULTS Hydrogen peroxide-induced oxidative stress significantly decreased the mean lifespan of C. elegans, which was restored to that of the control by the tocotrienol-rich fraction when administered before or both before and after the hydrogen peroxide. The accumulation of the age marker lipofuscin, which increased with hydrogen peroxide exposure, was decreased with upon treatment with the tocotrienol-rich fraction (p<0.05). The level of 8-hydroxy-2'-deoxyguanosine significantly increased in the hydrogen peroxide-induced group relative to the control. Treatment with the tocotrienol-rich fraction before or after hydrogen peroxide induction also increased the level of 8-hydroxy-2'-deoxyguanosine relative to the control. However, neither hydrogen peroxide nor the tocotrienol-rich fraction treatment affected the protein carbonyl content of the nematodes. CONCLUSION The tocotrienol-rich fraction restored the lifespan of oxidative stress-induced C. elegans and reduced the accumulation of lipofuscin but did not affect protein damage. In addition, DNA oxidation was increased.
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Affiliation(s)
- Goon Jo Aan
- Universiti Kebangsaan Malaysia, Department of Biochemistry, Faculty of Medicine, Kuala Lumpur City Campus, 50300 Kuala Lumpur/Malaysia.
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159
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Panieri E, Gogvadze V, Norberg E, Venkatesh R, Orrenius S, Zhivotovsky B. Reactive oxygen species generated in different compartments induce cell death, survival, or senescence. Free Radic Biol Med 2013; 57:176-87. [PMID: 23295411 DOI: 10.1016/j.freeradbiomed.2012.12.024] [Citation(s) in RCA: 107] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/09/2012] [Revised: 11/02/2012] [Accepted: 12/28/2012] [Indexed: 12/11/2022]
Abstract
Although reactive oxygen species (ROS) are well-established mediators of oxidative damage and cell demise, the mechanisms by which they trigger specific cell death modalities and the temporal/spatial requirements underlying this phenomenon are largely unknown. Yet, it is well established that most anticancer therapies depend on ROS production for efficient tumor eradication. Using several non-small-cell lung cancer cell lines, we have dissected how the site of ROS production and accumulation in various cell compartments affect cell fate. We demonstrate that high levels of exogenously generated H2O2 induce extensive DNA damage, ATP depletion, and severe cytotoxicity. Although these effects were independent of caspase activity, they could-at least in part-be prevented by RIP1 kinase inhibition. In contrast, low levels of exogenously produced H2O2 triggered a modest drop in ATP level, delayed toxicity, G2/M arrest, and cell senescence. Mitochondrially produced H2O2 induced a reversible ATP drop without affecting cell viability. Instead, the cells accumulated in the G1/S phase of the cell cycle and became senescent. Concomitant inhibition of glycolysis was found to markedly sensitize cells to death in the presence of otherwise nontoxic concentrations of H2O2, presumably by the inhibition of ATP-restoring mechanisms. Combined, our data provide evidence that ROS might dictate different cellular consequences depending on their overall concentration at steady-state levels and on their site of generation.
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Affiliation(s)
- Emiliano Panieri
- Division of Toxicology, Institute of Environmental Medicine, Karolinska Institutet, SE-171 77 Stockholm, Sweden
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160
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Xiao-Hong D, Chang-Qin X, Jian-Hua H, Wen-Jiang Z, Bing S. Icariin delays homocysteine-induced endothelial cellular senescence involving activation of the PI3K/AKT-eNOS signaling pathway. PHARMACEUTICAL BIOLOGY 2013; 51:433-440. [PMID: 23336586 DOI: 10.3109/13880209.2012.738332] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
CONTEXT Homocysteine-induced endothelial cellular senescence may contribute to some cardiovascular disorders. Icariin (ICA), a flavonoid derived from Epimedium sagittatum Maxim. (Berberidaceae), has been reported to increase production of nitric oxide (NO) and reduce reactive oxygen species (ROS) levels in human umbilical vein endothelial cells (HUVECs). OBJECTIVE To observe the effects of ICA on homocysteine-induced senescence and the underlying mechanisms in HUVECs. MATERIALS AND METHODS ICA at concentrations of 0.1, 1, and 5 μM was added into homocysteine pretreated HUVECs. Cellular senescence was assayed by senescence-associated β-galactosidase (SA-β-gal) staining and cumulative population doublings (CPDs). ICA (5 μM) was given orally to homocysteine-treated rats, luminal surface of aortic artery of rats was subjected to SA-β-gal staining. Protein expression was measured by western blot. RESULTS Homocysteine significantly increased cellular senescence both in vitro and in vivo. After treatment by ICA, the percentage of SA-β-gal-positive cells, and the ROS level significantly decreased. The CPDs were partially restored. ICA also significantly reduced the mean density of SA-β-gal staining in vivo. We found that NO production and phosphorylation of AKT, ERK, and endothelial NO synthase (eNOS) were elevated by ICA in HUVECs. Furthermore, the increased level of NO production was fully abolished by the phosphatidylinositol-3-kinase (PI3K) inhibitor wortmannin. The mitogen-activated protein kinase (MEK) inhibitor PD98059, which can inhibit phosphorylation of ERK, did not show this ability. DISCUSSION AND CONCLUSION Our results indicate that ICA delays homocyteine-induced endothelial senescence in vitro and in vivo. Activation of PI3K/Akt-eNOS-dependent signaling pathway may be responsible for this efficacy of ICA.
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Affiliation(s)
- Duan Xiao-Hong
- Institute of Integrated Traditional Chinese and Western Medicine, Huashan Hospital, Fudan University, Shanghai, China
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161
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Parsons BL, Myers MB. KRAS mutant tumor subpopulations can subvert durable responses to personalized cancer treatments. Per Med 2013; 10:191-199. [PMID: 27867401 DOI: 10.2217/pme.13.1] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
KRAS mutations in colorectal and lung cancers predict failure to respond to therapies that target the EGFR. Significant percentages of patients with KRAS wild-type tumors also fail to respond to these therapies. Relapse occurs in patients with KRAS wild-type and mutant tumors, with moderately longer progression-free survival in patients with KRAS wild-type tumors. Colon and lung tumors frequently carry KRAS mutant tumor subpopulations not detected by DNA sequencing. This suggests detected and undetected KRAS mutant subpopulations in colon and lung tumors are undermining the efficacy of anti-EGFR therapies. Therefore, consideration should be given to combining therapies that target KRAS mutant cells with those that downregulate EGFR signaling. As tumors are frequently polyclonal in origin and comprised of distinct clonal populations carrying complementing genetic and/or epigenetic lesions, preclinical models that assess the efficacy of combination therapies in the context of heterogeneous tumor cell populations will be essential for progress in this area.
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Affiliation(s)
- Barbara L Parsons
- US FDA, National Center for Toxicological Research, Division of Genetic & Molecular Toxicology, HFT-120, 3900 NCTR Road, Jefferson, AR 72079, USA
| | - Meagan B Myers
- US FDA, National Center for Toxicological Research, Division of Genetic & Molecular Toxicology, HFT-120, 3900 NCTR Road, Jefferson, AR 72079, USA
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162
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Rufini A, Tucci P, Celardo I, Melino G. Senescence and aging: the critical roles of p53. Oncogene 2013; 32:5129-43. [PMID: 23416979 DOI: 10.1038/onc.2012.640] [Citation(s) in RCA: 745] [Impact Index Per Article: 67.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2012] [Revised: 11/30/2012] [Accepted: 12/07/2012] [Indexed: 11/09/2022]
Abstract
p53 functions as a transcription factor involved in cell-cycle control, DNA repair, apoptosis and cellular stress responses. However, besides inducing cell growth arrest and apoptosis, p53 activation also modulates cellular senescence and organismal aging. Senescence is an irreversible cell-cycle arrest that has a crucial role both in aging and as a robust physiological antitumor response, which counteracts oncogenic insults. Therefore, via the regulation of senescence, p53 contributes to tumor growth suppression, in a manner strictly dependent by its expression and cellular context. In this review, we focus on the recent advances on the contribution of p53 to cellular senescence and its implication for cancer therapy, and we will discuss p53's impact on animal lifespan. Moreover, we describe p53-mediated regulation of several physiological pathways that could mediate its role in both senescence and aging.
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Affiliation(s)
- A Rufini
- Medical Research Council, Toxicology Unit, Leicester University, Leicester, UK
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163
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Cao Y, Yang T, Gu C, Yi D. Pigment epithelium-derived factor delays cellular senescence of human mesenchymal stem cells in vitro by reducing oxidative stress. Cell Biol Int 2013; 37:305-13. [PMID: 23359450 DOI: 10.1002/cbin.10041] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2012] [Accepted: 12/23/2012] [Indexed: 12/12/2022]
Abstract
Mesenchymal stem cells (MSCs) are multipotent progenitor cells that represent a promising approach in the field of regenerative medicine; however, this potential diminishes with senescence. Pigment epithelium-derived factor (PEDF) gives some protection by reducing oxidative stress, which is known to accelerate cellular senescence. Thus we hypothesized that PEDF could delay senescence during MSC expansion by reducing oxidative stress. Proliferation and differentiation potentials, oxidative stress, senescence and p53/p16 expressions have been examined. In MSCs cultured under normoxic conditions treated with PEDF, proliferative lifespan in vitro was significantly increased compared with control group not given PEDF, with ∼10 additional population doublings (PD) occurring before terminal growth arrest. Most of the MSCs cultured under normoxic conditions ceased to proliferate after 20-28 PD, while few senescent cells were found in the hypoxic, PEDF-hypoxic and PEDF-normoxic cultures; this was associated with downregulation of p53 and p16 expression and decreased oxidative stress. PEDF also preserved differentiation potentials of MSCs compared with the control group. Thus PEDF suppression of oxidative stress delays cellular senescence and allows greater expansion of MSCs.
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Affiliation(s)
- Yukun Cao
- Department of Cardiovascular Surgery, Xijing Hospital, Fourth Military Medical University, Xi'an 710032, Shaanxi Province, China
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164
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Abstract
Estrogen provides many beneficial effects early in life by regulating normal tissue development and several physiological functions. While estrogen replacement therapy (ERT) in women was expected to reduce the health risks associated with the age-related decline in estrogen levels during menopause, ERT also resulted in increased progression to other types of diseases. Hence, distinguishing the signaling pathways that regulate the beneficial and detrimental effects of estrogen is important for developing interventions that selectively harness the hormone's beneficial effects, while minimizing its side effects. Estrogen can minimize mitochondrial dysfunction, which is thought to contribute to aging phenotypes. Decline in estrogen levels during menopause may lead to progressive mitochondrial dysfunction and may permanently alter cellular response, including that of estrogen (i.e., ERT). This review discusses the interplay between estrogen and mitochondrial function during the aging process and suggests a potential role of mitochondria in influencing the pleiotropic action of estrogen.
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Affiliation(s)
- Michael C Velarde
- Buck Institute for Research on Aging, Novato, California 94945, USA.
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165
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Romanov VS, Pospelov VA, Pospelova TV. Cyclin-dependent kinase inhibitor p21(Waf1): contemporary view on its role in senescence and oncogenesis. BIOCHEMISTRY (MOSCOW) 2012; 77:575-84. [PMID: 22817456 DOI: 10.1134/s000629791206003x] [Citation(s) in RCA: 95] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
p21(Waf1) was identified as a protein suppressing cyclin E/A-CDK2 activity and was originally considered as a negative regulator of the cell cycle and a tumor suppressor. It is now considered that p21(Waf1) has alternative functions, and the view of its role in cellular processes has begun to change. At present, p21(Waf1) is known to be involved in regulation of fundamental cellular programs: cell proliferation, differentiation, migration, senescence, and apoptosis. In fact, it not only exhibits antioncogenic, but also oncogenic properties. This review provides a contemporary understanding of the functions of p21(Waf1) depending on its intracellular localization. On one hand, when in the nucleus, it serves as a negative cell cycle regulator and tumor suppressor, in particular by participating in the launch of a senescence program. On the other hand, when p21(Waf1) is localized in the cytoplasm, it acts as an oncogene by regulating migration, apoptosis, and proliferation.
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Affiliation(s)
- V S Romanov
- Institute of Cytology, Russian Academy of Sciences, Tikhoretsky pr. 4, 194064 St. Petersburg, Russia.
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166
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Favaro E, Bensaad K, Chong MG, Tennant DA, Ferguson DJP, Snell C, Steers G, Turley H, Li JL, Günther UL, Buffa FM, McIntyre A, Harris AL. Glucose utilization via glycogen phosphorylase sustains proliferation and prevents premature senescence in cancer cells. Cell Metab 2012. [PMID: 23177934 DOI: 10.1016/j.cmet.2012.10.017] [Citation(s) in RCA: 291] [Impact Index Per Article: 24.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Metabolic reprogramming of cancer cells provides energy and multiple intermediates critical for cell growth. Hypoxia in tumors represents a hostile environment that can encourage these transformations. We report that glycogen metabolism is upregulated in tumors in vivo and in cancer cells in vitro in response to hypoxia. In vitro, hypoxia induced an early accumulation of glycogen, followed by a gradual decline. Concordantly, glycogen synthase (GYS1) showed a rapid induction, followed by a later increase of glycogen phosphorylase (PYGL). PYGL depletion and the consequent glycogen accumulation led to increased reactive oxygen species (ROS) levels that contributed to a p53-dependent induction of senescence and markedly impaired tumorigenesis in vivo. Metabolic analyses indicated that glycogen degradation by PYGL is important for the optimal function of the pentose phosphate pathway. Thus, glycogen metabolism is a key pathway induced by hypoxia, necessary for optimal glucose utilization, which represents a targetable mechanism of metabolic adaptation.
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Affiliation(s)
- Elena Favaro
- Molecular Oncology Laboratories, Weatherall Institute of Molecular Medicine, University of Oxford, John Radcliffe Hospital, Oxford OX3 9DS, UK
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167
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The E6AP E3 ubiquitin ligase regulates the cellular response to oxidative stress. Oncogene 2012; 32:3510-9. [DOI: 10.1038/onc.2012.365] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2012] [Revised: 06/20/2012] [Accepted: 07/04/2012] [Indexed: 11/09/2022]
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168
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Murphy KC, Volkert MR. Structural/functional analysis of the human OXR1 protein: identification of exon 8 as the anti-oxidant encoding function. BMC Mol Biol 2012; 13:26. [PMID: 22873401 PMCID: PMC3462732 DOI: 10.1186/1471-2199-13-26] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2011] [Accepted: 07/24/2012] [Indexed: 12/27/2022] Open
Abstract
Background The human OXR1 gene belongs to a class of genes with conserved functions that protect cells from reactive oxygen species (ROS). The gene was found using a screen of a human cDNA library by its ability to suppress the spontaneous mutator phenotype of an E. coli mutH nth strain. The function of OXR1 is unknown. The human and yeast genes are induced by oxidative stress and targeted to the mitochondria; the yeast gene is required for resistance to hydrogen peroxide. Multiple spliced isoforms are expressed in a variety of human tissues, including brain. Results In this report, we use a papillation assay that measures spontaneous mutagenesis of an E. coli mutM mutY strain, a host defective for oxidative DNA repair. Papillation frequencies with this strain are dependent upon a G→T transversion in the lacZ gene (a mutation known to occur as a result of oxidative damage) and are suppressed by in vivo expression of human OXR1. N-terminal, C-terminal and internal deletions of the OXR1 gene were constructed and tested for suppression of the mutagenic phenotype of the mutM mutY strain. We find that the TLDc domain, encoded by the final four exons of the OXR1 gene, is not required for papillation suppression in E. coli. Instead, we show that the protein segment encoded by exon 8 of OXR1 is responsible for the suppression of oxidative damage in E. coli. Conclusion The protein segment encoded by OXR1 exon 8 plays an important role in the anti-oxidative function of the human OXR1 protein. This result suggests that the TLDc domain, found in OXR1 exons 12–16 and common in many proteins with nuclear function, has an alternate (undefined) role other than oxidative repair.
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Affiliation(s)
- Kenan C Murphy
- Department of Microbiology and Physiological Systems, University of Massachusetts Medical School, Worcester, MA 01655, USA.
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169
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Gillooly JF, Hayward A, Hou C, Burleigh JG. Explaining differences in the lifespan and replicative capacity of cells: a general model and comparative analysis of vertebrates. Proc Biol Sci 2012; 279:3976-80. [PMID: 22810428 DOI: 10.1098/rspb.2012.1129] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
A better understanding of the factors that govern individual cell lifespan and the replicative capacity of cells (i.e. Hayflick's limit) is important for addressing disease progression and ageing. Estimates of cell lifespan in vivo and the replicative capacity of cell lines in culture vary substantially both within and across species, but the underlying reasons for this variability remain unclear. Here, we address this issue by presenting a quantitative model of cell lifespan and cell replicative capacity. The model is based on the relationship between cell mortality and metabolic rate, which is supported with data for different cell types from ectotherms and endotherms. These data indicate that much of the observed variation in cell lifespan and cell replicative capacity is explained by differences in cellular metabolic rate, and thus by the three primary factors that control metabolic rate: organism size, organism temperature and cell size. Individual cell lifespan increases as a power law with both body mass and cell mass, and decreases exponentially with increasing temperature. The replicative capacity of cells also increases with body mass, but is independent of temperature. These results provide a point of departure for future comparative studies of cell lifespan and replicative capacity in the laboratory and in the field.
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Affiliation(s)
- James F Gillooly
- Department of Biology, University of Florida, Gainesville, FL 32611, USA.
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170
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Sfikas A, Batsi C, Tselikou E, Vartholomatos G, Monokrousos N, Pappas P, Christoforidis S, Tzavaras T, Kanavaros P, Gorgoulis VG, Marcu KB, Kolettas E. The canonical NF-κB pathway differentially protects normal and human tumor cells from ROS-induced DNA damage. Cell Signal 2012; 24:2007-23. [PMID: 22750558 DOI: 10.1016/j.cellsig.2012.06.010] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2012] [Revised: 06/06/2012] [Accepted: 06/16/2012] [Indexed: 10/28/2022]
Abstract
DNA damage responses (DDR) invoke senescence or apoptosis depending on stimulus intensity and the degree of activation of the p53-p21(Cip1/Waf1) axis; but the functional impact of NF-κB signaling on these different outcomes in normal vs. human cancer cells remains poorly understood. We investigated the NF-κB-dependent effects and mechanism underlying reactive oxygen species (ROS)-mediated DDR outcomes of normal human lung fibroblasts (HDFs) and A549 human lung cancer epithelial cells. To activate DDR, ROS accumulation was induced by different doses of H(2)O(2). The effect of ROS induction caused a G2 or G2-M phase cell cycle arrest of both human cell types. However, ROS-mediated DDR eventually culminated in different end points with HDFs undergoing premature senescence and A549 cancer cells succumbing to apoptosis. NF-κB p65/RelA nuclear translocation and Ser536 phosphorylation were induced in response to H(2)O(2)-mediated ROS accumulation. Importantly, blocking the activities of canonical NF-κB subunits with an IκBα super-repressor or suppressing canonical NF-κB signaling by IKKβ knock-down accelerated HDF premature senescence by up-regulating the p53-p21(Cip1/Waf1) axis; but inhibiting the canonical NF-κB pathway exacerbated H(2)O(2)-induced A549 cell apoptosis. HDF premature aging occurred in conjunction with γ-H2AX chromatin deposition, senescence-associated heterochromatic foci and beta-galactosidase staining. p53 knock-down abrogated H(2)O(2)-induced premature senescence of vector control- and IκBαSR-expressing HDFs functionally linking canonical NF-κB-dependent control of p53 levels to ROS-induced HDF senescence. We conclude that IKKβ-driven canonical NF-κB signaling has different functional roles for the outcome of ROS responses in the contexts of normal vs. human tumor cells by respectively protecting them against DDR-dependent premature senescence and apoptosis.
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Affiliation(s)
- Alexandros Sfikas
- Cell and Molecular Physiology Unit, Laboratory of Physiology, School of Medicine, University of Ioannina, 45110 Ioannina, Greece
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Zoumpoulidou G, Broceño C, Li H, Bird D, Thomas G, Mittnacht S. Role of the tripartite motif protein 27 in cancer development. J Natl Cancer Inst 2012; 104:941-52. [PMID: 22556269 DOI: 10.1093/jnci/djs224] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/25/2024] Open
Abstract
BACKGROUND The tripartite motif family protein 27 (TRIM27) is a transcriptional repressor that interacts with, and attenuates senescence induction by, the retinoblastoma-associated protein (RB1). High expression of TRIM27 was noted in several human cancer types including breast and endometrial cancer, where elevated TRIM27 expression predicts poor prognosis. Here, we investigated the role of TRIM27 expression in cancer development. METHODS We assessed TRIM27 expression in human cancer using cancer profiling arrays containing paired tumor and normal cRNA (n = 261) as well as in murine skin cancer induced by 7, 12-dimethylbenzanthracene (DMBA)/12-O-tetradecanoylphorbol-13-acetate (TPA). We generated mice with disrupted expression of murine TRIM27 (Trim27(-/-)) and assessed their susceptibility to DMBA/TPA-induced skin tumor development compared with isogenic littermates (n = 26 mice per group). We assessed the effect of Trim27 loss on senescence propensity in mouse embryonic fibroblasts (MEFs) by quantifying cell proliferation alongside senescence markers (senescence-associated β-galactosidase [SA-β-gal] activity and hypertrophic cell morphology). The contribution of RB1 on senescence and cancer susceptibility (n > 20 mice per group) in Trim27(-/-) backgrounds was also assessed. Data were analyzed using the Student's t, χ(2), or log-rank test as indicated. All statistical tests were two-sided. RESULTS TRIM27 transcript levels are statistically significantly increased in common human cancers, including colon and lung, vs normal tissues (TRIM27 expression relative to ubiquitin: cancers vs normal tissues, mean = 0.59, 95% confidence interval [CI] = 0.55 to 0.63 vs mean = 0.46, 95% CI =0.43 to 0.49, P < .001) as well as in chemically induced mouse skin cancer compared with matched normal tissue (Trim27 expression relative to Gapdh control: tumor vs normal skin, mean = 4.2, 95% CI = 3.97 to 4.43 vs mean = 0.96, 95% CI = 0.69 to 1.2, P < .001). Trim27(-/-) mice (n = 14) were resistant to chemically induced skin cancer development (eight [57.2%] of 14 mice were tumor free) compared with Trim27(+/+) wild-type littermates (n = 13) (one [7.7%] of 13 mice was tumor free). Trim27(-/-) MEFs show enhanced senescence propensity in response to replicative (percentage of SA-β-gal-positive cells: Trim27(+/+) MEFs vs Trim27(-/-) MEFs, mean = 14.2%, 95% CI = 11.1% to 17.4% vs mean = 53.3%, 95% CI = 48.7% to 57.9%, P < .001) or oncogenic stress (percentage of SA-β-gal-positive cells: Trim27(+/+) MEFs + Ras vs Trim27(-/-) MEFs + Ras, mean = 24.0%, 95% CI = 19.9% to 28.1% vs mean = 37.3%, 95% CI = 32.2% to 42.4%, P < .05) compared with Trim27(+/+) MEFs. These responses were alleviated following inactivation of murine RB1 (Rb1). Furthermore, Trim27(-/-) mice are not protected from cancers arising as a consequence of Rb1 deletion (median survival: Trim27(-/-)Rb(+/-) vs Trim27(+/+)Rb(+/-), 14 vs 13 months; difference = 1.0 month, 95% CI = 0.5 to 1.6 months, P = .14). CONCLUSION TRIM27 expression is a modifier of disease incidence and progression relevant to the development of common human cancers and is a potential target for intervention in cancer.
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Affiliation(s)
- Georgia Zoumpoulidou
- Section of Cancer Biology, University College London Cancer Institute, University College London, 72 Huntley St, London WC1E 6DD, UK.
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172
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Klement K, Melle C, Murzik U, Diekmann S, Norgauer J, Hemmerich P. Accumulation of annexin A5 at the nuclear envelope is a biomarker of cellular aging. Mech Ageing Dev 2012; 133:508-22. [PMID: 22728018 DOI: 10.1016/j.mad.2012.06.003] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2011] [Revised: 04/20/2012] [Accepted: 06/13/2012] [Indexed: 01/07/2023]
Abstract
Cellular senescence is a permanent cell cycle arrest induced by short telomeres or oncogenic stress in vitro and in vivo. Because no single of the established biomarkers can reliably identify senescent cells, the application of new ones may aid the diagnosis of aged cells. Here we show that annexin A5 accumulates at the nuclear envelope during replicative and drug-induced cellular senescence in primary human fibroblasts. This new cellular aging phenotype that we have termed SA-ANX5 (senescence-associated accumulation at the nuclear envelope of annexin A5) is as efficient and quantitative as the well-established senescence-associated β-galactosidase activity assay and p21 immunoreactivity. SA-ANX5 is also observed in aged human skin where is exclusively detected in DNA damage foci-positive/Ki-67-negative cells. We also observed that depletion of annexin A5 by siRNA in human fibroblasts accelerates premature senescence through the p38MAP kinase pathway. These observations establish SA-ANX5 as a new biomarker for cellular aging and implicate a functional role for annexin A5 in cellular senescence.
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Affiliation(s)
- Karolin Klement
- Leibniz-Institute for Age Research-Fritz Lipmann Institute, Jena, Germany.
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173
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Capparelli C, Whitaker-Menezes D, Guido C, Balliet R, Pestell TG, Howell A, Sneddon S, Pestell RG, Martinez-Outschoorn U, Lisanti MP, Sotgia F. CTGF drives autophagy, glycolysis and senescence in cancer-associated fibroblasts via HIF1 activation, metabolically promoting tumor growth. Cell Cycle 2012; 11:2272-84. [PMID: 22684333 PMCID: PMC3383589 DOI: 10.4161/cc.20717] [Citation(s) in RCA: 107] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Previous studies have demonstrated that loss of caveolin-1 (Cav-1) in stromal cells drives the activation of the TGF-β signaling, with increased transcription of TGF-β target genes, such as connective tissue growth factor (CTGF). In addition, loss of stromal Cav-1 results in the metabolic reprogramming of cancer-associated fibroblasts, with the induction of autophagy and glycolysis. However, it remains unknown if activation of the TGF-β / CTGF pathway regulates the metabolism of cancer-associated fibroblasts. Therefore, we investigated whether CTGF modulates metabolism in the tumor microenvironment. For this purpose, CTGF was overexpressed in normal human fibroblasts or MDA-MB-231 breast cancer cells. Overexpression of CTGF induces HIF-1α-dependent metabolic alterations, with the induction of autophagy/mitophagy, senescence, and glycolysis. Here, we show that CTGF exerts compartment-specific effects on tumorigenesis, depending on the cell-type. In a xenograft model, CTGF overexpressing fibroblasts promote the growth of co-injected MDA-MB-231 cells, without any increases in angiogenesis. Conversely, CTGF overexpression in MDA-MB-231 cells dramatically inhibits tumor growth in mice. Intriguingly, increased extracellular matrix deposition was seen in tumors with either fibroblast or MDA-MB-231 overexpression of CTGF. Thus, the effects of CTGF expression on tumor formation are independent of its extracellular matrix function, but rather depend on its ability to activate catabolic metabolism. As such, CTGF-mediated induction of autophagy in fibroblasts supports tumor growth via the generation of recycled nutrients, whereas CTGF-mediated autophagy in breast cancer cells suppresses tumor growth, via tumor cell self-digestion. Our studies shed new light on the compartment-specific role of CTGF in mammary tumorigenesis, and provide novel insights into the mechanism(s) generating a lethal tumor microenvironment in patients lacking stromal Cav-1. As loss of Cav-1 is a stromal marker of poor clinical outcome in women with primary breast cancer, dissecting the downstream signaling effects of Cav-1 are important for understanding disease pathogenesis, and identifying novel therapeutic targets.
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Affiliation(s)
- Claudia Capparelli
- The Jefferson Stem Cell Biology and Regenerative Medicine Center, Kimmel Cancer Center, Thomas Jefferson University, Philadelphia, PA, USA
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174
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Mikuła-Pietrasik J, Kuczmarska A, Rubiś B, Filas V, Murias M, Zieliński P, Piwocka K, Książek K. Resveratrol delays replicative senescence of human mesothelial cells via mobilization of antioxidative and DNA repair mechanisms. Free Radic Biol Med 2012; 52:2234-45. [PMID: 22579575 DOI: 10.1016/j.freeradbiomed.2012.03.014] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/15/2011] [Revised: 03/23/2012] [Accepted: 03/25/2012] [Indexed: 01/08/2023]
Abstract
Resveratrol (3,4',5-trihydroxy-trans-stilbene; RVT) is a natural phytoestrogen known to modulate the rate of senescence in cultured cells. The mechanism by which RVT affects this process is still elusive. In this paper we used human peritoneal mesothelial cells (HPMCs) to examine the effect of RVT (0.5 and 10 μM) on their growth and senescence, with particular emphasis paid to parameters associated with oxidative stress. The results showed that RVT used at a concentration of 0.5 μM (but not at 10 μM) markedly improved HPMC growth capacity, as evidenced by elevated expression of PCNA antigen, augmented fraction of cells in the S phase of the cell cycle, and increased number of divisions achieved before senescence. These effects coincided with diminished expression and activity of senescence-associated β-galactosidase but were not associated with changes in the telomere length and an incidence of apoptosis. Moreover cells exposed to 0.5 μM RVT were characterized by increased release of reactive oxygen species, which was accompanied by up-regulated biogenesis of mitochondria and collapsed mitochondrial membrane potential. At the same time, they displayed increased activity of superoxide dismutase and reduced DNA damage (8-OH-dG and γ-H2A.X level). The efficiency of 8-OH-dG repair was increased which could be related to increased activity of DNA glycosylase I (hOgg1). As shown using RT-PCR, expression of hOgg1 mRNA in these cells was markedly elevated. Collectively, our results indicate that delayed senescence of HPMCs exposed to RVT may be associated with mobilization of antioxidative and DNA repair mechanisms.
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Affiliation(s)
- Justyna Mikuła-Pietrasik
- Department of Pathophysiology, Poznań University of Medical Sciences, Święcickiego 6, 60-781 Poznań, Poland
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175
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Freund A, Laberge RM, Demaria M, Campisi J. Lamin B1 loss is a senescence-associated biomarker. Mol Biol Cell 2012; 23:2066-75. [PMID: 22496421 PMCID: PMC3364172 DOI: 10.1091/mbc.e11-10-0884] [Citation(s) in RCA: 637] [Impact Index Per Article: 53.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2011] [Revised: 03/30/2012] [Accepted: 04/05/2012] [Indexed: 12/30/2022] Open
Abstract
Cellular senescence is a potent tumor-suppressive mechanism that arrests cell proliferation and has been linked to aging. However, studies of senescence have been impeded by the lack of simple, exclusive biomarkers of the senescent state. Senescent cells develop characteristic morphological changes, which include enlarged and often irregular nuclei and chromatin reorganization. Because alterations to the nuclear lamina can affect both nuclear morphology and gene expression, we examined the nuclear lamina of senescent cells. We show here than lamin B1 is lost from primary human and murine cell strains when they are induced to senesce by DNA damage, replicative exhaustion, or oncogene expression. Lamin B1 loss did not depend on the p38 mitogen-activated protein kinase, nuclear factor-κB, ataxia telangiectasia-mutated kinase, or reactive oxygen species signaling pathways, which are positive regulators of senescent phenotypes. However, activation of either the p53 or pRB tumor suppressor pathway was sufficient to induce lamin B1 loss. Lamin B1 declined at the mRNA level via a decrease in mRNA stability rather than by the caspase-mediated degradation seen during apoptosis. Last, lamin B1 protein and mRNA declined in mouse tissue after senescence was induced by irradiation. Our findings suggest that lamin B1 loss can serve as biomarker of senescence both in culture and in vivo.
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Affiliation(s)
- Adam Freund
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720
- Buck Institute for Research on Aging, Novato, CA 94945
- Lawrence Berkeley National Laboratory, Berkeley, CA 94720
| | | | - Marco Demaria
- Buck Institute for Research on Aging, Novato, CA 94945
| | - Judith Campisi
- Buck Institute for Research on Aging, Novato, CA 94945
- Lawrence Berkeley National Laboratory, Berkeley, CA 94720
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Goronzy JJ, Li G, Yu M, Weyand CM. Signaling pathways in aged T cells - a reflection of T cell differentiation, cell senescence and host environment. Semin Immunol 2012; 24:365-72. [PMID: 22560928 DOI: 10.1016/j.smim.2012.04.003] [Citation(s) in RCA: 85] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/23/2012] [Revised: 04/01/2012] [Accepted: 04/09/2012] [Indexed: 01/04/2023]
Abstract
With increasing age, the ability of the immune system to protect against new antigenic challenges or to control chronic infections erodes. Decline in thymic function and cumulating antigenic experiences of acute and chronic infections threaten T cell homeostasis, but insufficiently explain the failing immune competence and the increased susceptibility for autoimmunity. Alterations in signaling pathways in the aging T cells account for many of the age-related defects. Signaling threshold calibrations seen with aging frequently built on mechanisms that are operational in T cell development and T cell differentiation or are adaptations to the changing environment in the aging host. Age-related changes in transcription of receptors and signaling molecules shift the balance towards inhibitory pathways, most dominantly seen in CD8 T cells and to a lesser degree in CD4 T cells. Prominent examples are the expression of negative regulatory receptors of the CD28 and the TNF receptor superfamilies as well the expression of various cytoplasmic and nuclear dual-specific phosphatases.
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Affiliation(s)
- Jörg J Goronzy
- Department of Medicine, Stanford University School of Medicine, Stanford, CA 94305, United States.
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177
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Abstract
PURPOSE OF REVIEW The kallikrein-kinin system (KKS) constitutes a complex multienzyme cascade that produces several bioactive kinin peptides and their derivatives including bradykinin. In addition to the classical notion of the KKS as a potent vasodilator and a mediator of inflammatory responses, recent studies suggest a link between the KKS and oxidative stress. A number of established mouse models with altered levels of KKS components opened the way to evaluate precise functions of the KKS. Here we review recent findings on the role of the KKS in cardiovascular diseases and chronic kidney diseases, and discuss potential benefits of KKS activation in these diseases. RECENT FINDINGS Deletion of both B1R and B2R in a diabetic mouse model exacerbates its renal phenotypes, suggesting that the KKS exerts protective effects on diabetic nephropathy by suppressing oxidative stress, presumably via nitric oxide and prostaglandins. SUMMARY Accumulating evidence has highlighted the importance of the KKS as a protective system against oxidative stress and organ damage in the heart and kidney. The activation of the KKS by angiotensin I-converting enzyme inhibitors and vasopeptidase inhibitors is likely to be beneficial in senescence-associated cardiovascular diseases and chronic kidney diseases.
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178
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Giordano CR, Terlecky SR. Peroxisomes, cell senescence, and rates of aging. Biochim Biophys Acta Mol Basis Dis 2012; 1822:1358-62. [PMID: 22497955 DOI: 10.1016/j.bbadis.2012.03.013] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2012] [Revised: 03/02/2012] [Accepted: 03/22/2012] [Indexed: 12/31/2022]
Abstract
The peroxisome is functionally integrated into an exquisitely complex network of communicating endomembranes which is only beginning to be appreciated. Despite great advances in identifying essential components and characterizing molecular mechanisms associated with the organelle's biogenesis and function, there is a large gap in our understanding of how peroxisomes are incorporated into metabolic pathways and subcellular communication networks, how they contribute to cellular aging, and where their influence is manifested on the initiation and progression of degenerative disease. In this review, we summarize recent evidence pointing to the organelle as an important regulator of cellular redox balance with potentially far-reaching effects on cell aging and the genesis of human disease. The roles of the organelle in lipid homeostasis, anaplerotic reactions, and other critical metabolic and biochemical processes are addressed elsewhere in this volume. This article is part of a Special Issue entitled: Metabolic Functions and Biogenesis of Peroxisomes in Health and Disease.
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Affiliation(s)
- Courtney R Giordano
- Department of Pharmacology, Wayne State University School of Medicine, Detroit, MI, USA
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Barascu A, Le Chalony C, Pennarun G, Genet D, Imam N, Lopez B, Bertrand P. Oxidative stress induces an ATM-independent senescence pathway through p38 MAPK-mediated lamin B1 accumulation. EMBO J 2012; 31:1080-94. [PMID: 22246186 PMCID: PMC3297999 DOI: 10.1038/emboj.2011.492] [Citation(s) in RCA: 152] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2011] [Accepted: 12/19/2011] [Indexed: 12/24/2022] Open
Abstract
We report crosstalk between three senescence-inducing conditions, DNA damage response (DDR) defects, oxidative stress (OS) and nuclear shape alterations. The recessive autosomal genetic disorder Ataxia telangiectasia (A-T) is associated with DDR defects, endogenous OS and premature ageing. Here, we find frequent nuclear shape alterations in A-T cells, as well as accumulation of the key nuclear architecture component lamin B1. Lamin B1 overexpression is sufficient to induce nuclear shape alterations and senescence in wild-type cells, and normalizing lamin B1 levels in A-T cells reciprocally reduces both nuclear shape alterations and senescence. We further show that OS increases lamin B1 levels through p38 Mitogen Activated Protein kinase activation. Lamin B1 accumulation and nuclear shape alterations also occur during stress-induced senescence and oncogene-induced senescence (OIS), two canonical senescence situations. These data reveal lamin B1 as a general molecular mediator that controls OS-induced senescence, independent of established Ataxia Telangiectasia Mutated (ATM) roles in OIS.
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Affiliation(s)
- Aurelia Barascu
- CNRS, UMR217, Fontenay aux Roses, France
- CEA, DSV, Institut de Radiobiologie Cellulaire et Moléculaire, Fontenay aux Roses, France
| | - Catherine Le Chalony
- CNRS, UMR217, Fontenay aux Roses, France
- CEA, DSV, Institut de Radiobiologie Cellulaire et Moléculaire, Fontenay aux Roses, France
| | - Gaëlle Pennarun
- CNRS, UMR217, Fontenay aux Roses, France
- CEA, DSV, Institut de Radiobiologie Cellulaire et Moléculaire, Fontenay aux Roses, France
| | - Diane Genet
- CNRS, UMR217, Fontenay aux Roses, France
- CEA, DSV, Institut de Radiobiologie Cellulaire et Moléculaire, Fontenay aux Roses, France
| | - Naima Imam
- CNRS, UMR217, Fontenay aux Roses, France
- CEA, DSV, Institut de Radiobiologie Cellulaire et Moléculaire, Fontenay aux Roses, France
| | - Bernard Lopez
- CNRS, UMR217, Fontenay aux Roses, France
- CEA, DSV, Institut de Radiobiologie Cellulaire et Moléculaire, Fontenay aux Roses, France
| | - Pascale Bertrand
- CNRS, UMR217, Fontenay aux Roses, France
- CEA, DSV, Institut de Radiobiologie Cellulaire et Moléculaire, Fontenay aux Roses, France
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180
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Wang CT, Chen YC, Wang YY, Huang MH, Yen TL, Li H, Liang CJ, Sang TK, Ciou SC, Yuh CH, Wang CY, Brummel TJ, Wang HD. Reduced neuronal expression of ribose-5-phosphate isomerase enhances tolerance to oxidative stress, extends lifespan, and attenuates polyglutamine toxicity in Drosophila. Aging Cell 2012; 11:93-103. [PMID: 22040003 DOI: 10.1111/j.1474-9726.2011.00762.x] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
Abstract
Aging and age-related diseases can be viewed as the result of the lifelong accumulation of stress insults. The identification of mutant strains and genes that are responsive to stress and can alter longevity profiles provides new therapeutic targets for age-related diseases. Here we reported that a Drosophila strain with reduced expression of ribose-5-phosphate isomerase (rpi), EP2456, exhibits increased resistance to oxidative stress and enhanced lifespan. In addition, the strain also displays higher levels of NADPH. The knockdown of rpi in neurons by double-stranded RNA interference recapitulated the lifespan extension and oxidative stress resistance in Drosophila. This manipulation was also found to ameliorate the effects of genetic manipulations aimed at creating a model for studying Huntington's disease by overexpression of polyglutamine in the eye, suggesting that modulating rpi levels could serve as a treatment for normal aging as well as for polyglutamine neurotoxicity.
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Affiliation(s)
- Ching-Tzu Wang
- Institute of Biotechnology, National Tsing Hua University, Hsinchu, Taiwan, ROC
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Velarde MC, Flynn JM, Day NU, Melov S, Campisi J. Mitochondrial oxidative stress caused by Sod2 deficiency promotes cellular senescence and aging phenotypes in the skin. Aging (Albany NY) 2012; 4:3-12. [PMID: 22278880 PMCID: PMC3292901 DOI: 10.18632/aging.100423] [Citation(s) in RCA: 192] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2012] [Accepted: 01/18/2012] [Indexed: 12/28/2022]
Abstract
Cellular senescence arrests the proliferation of mammalian cells at risk for neoplastic transformation, and is also associated with aging. However, the factors that cause cellular senescence during aging are unclear. Excessive reactive oxygen species (ROS) have been shown to cause cellular senescence in culture, and accumulated molecular damage due to mitochondrial ROS has long been thought to drive aging phenotypesin vivo. Here, we test the hypothesis that mitochondrial oxidative stress can promote cellular senescence in vivo and contribute to aging phenotypes in vivo, specifically in the skin. We show that the number of senescent cells, as well as impaired mitochondrial (complex II) activity increase in naturally aged mouse skin. Using a mouse model of genetic Sod2 deficiency, we show that failure to express this important mitochondrial anti-oxidant enzyme also impairs mitochondrial complex II activity, causes nuclear DNA damage, and induces cellular senescence but not apoptosis in the epidermis. Sod2 deficiency also reduced the number of cells and thickness of the epidermis, while increasing terminal differentiation. Our results support the idea that mitochondrial oxidative stress and cellular senescence contribute to aging skin phenotypes in vivo.
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Affiliation(s)
| | - James M. Flynn
- Buck Institute for Research on Aging, Novato, CA 94945, USA
| | | | - Simon Melov
- Buck Institute for Research on Aging, Novato, CA 94945, USA
| | - Judith Campisi
- Buck Institute for Research on Aging, Novato, CA 94945, USA
- Lawrence Berkley National Laboratory, Berkeley, CA 94720, USA
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182
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MicroRNAs as a novel cellular senescence regulator. Ageing Res Rev 2012; 11:41-50. [PMID: 21689787 DOI: 10.1016/j.arr.2011.06.001] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2011] [Revised: 05/09/2011] [Accepted: 06/02/2011] [Indexed: 12/26/2022]
Abstract
Cellular senescence is a program activated in normal cells in response to various types of stresses and is manifested by permanent arrest of cell cycle. Cellular senescence is closely related to tumor suppression, and may contribute to the ageing of organisms. The complex senescence cell phenotype has many different mechanisms. Recent studies have provided important insights regarding the role played by miRNAs during cellular senescence as a novel molecular mechanism. In this article, we will review the latest advances in the identification and validation of senescence-regulatory miRNAs and the possible mechanisms.
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183
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Momtaz S, Abdollahi M. A Comprehensive Review of Biochemical and Molecular Evidences from Animal and Human Studies on the Role of Oxidative Stress in Aging: An Epiphenomenon or the Cause. ACTA ACUST UNITED AC 2011. [DOI: 10.3923/ajava.2012.1.19] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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184
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Oxidative stress, mitochondrial dysfunction, and aging. JOURNAL OF SIGNAL TRANSDUCTION 2011; 2012:646354. [PMID: 21977319 PMCID: PMC3184498 DOI: 10.1155/2012/646354] [Citation(s) in RCA: 591] [Impact Index Per Article: 45.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 05/15/2011] [Accepted: 08/03/2011] [Indexed: 12/31/2022]
Abstract
Aging is an intricate phenomenon characterized by progressive decline in physiological functions and increase in mortality that is often accompanied by many pathological diseases. Although aging is almost universally conserved among all organisms, the underlying molecular mechanisms of aging remain largely elusive. Many theories of aging have been proposed, including the free-radical and mitochondrial theories of aging. Both theories speculate that cumulative damage to mitochondria and mitochondrial DNA (mtDNA) caused by reactive oxygen species (ROS) is one of the causes of aging. Oxidative damage affects replication and transcription of mtDNA and results in a decline in mitochondrial function which in turn leads to enhanced ROS production and further damage to mtDNA. In this paper, we will present the current understanding of the interplay between ROS and mitochondria and will discuss their potential impact on aging and age-related diseases.
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185
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Shiota M, Yokomizo A, Naito S. Oxidative stress and androgen receptor signaling in the development and progression of castration-resistant prostate cancer. Free Radic Biol Med 2011; 51:1320-8. [PMID: 21820046 DOI: 10.1016/j.freeradbiomed.2011.07.011] [Citation(s) in RCA: 90] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/12/2011] [Revised: 07/09/2011] [Accepted: 07/13/2011] [Indexed: 11/25/2022]
Abstract
Aberrant androgen receptor (AR) signaling plays a critical role in androgen-dependent prostate cancer (PCa), as well as in castration-resistant PCa (CRPC). Oxidative stress seems to contribute to the tumorigenesis and progression of PCa, as well as the development of CRPC, via activation of AR signaling. This notion is supported by the fact that there is an aberrant or improper regulation of the redox status in these disorders. Additionally, androgen-deprivation-induced oxidative stress seems to be involved in the pathogenesis of several disorders caused by androgen-deprivation therapy (ADT), including osteoporosis, neurodegenerative disease, and cardiovascular disease. Oxidative stress can be suppressed with antioxidants or via a reduction in reactive oxygen species production. Thus, developing new therapeutic agents that reduce oxidative stress might be useful in preventing the conversion of androgen-dependent PCa into CRPC, as well as reducing the adverse effects associated with ADT. The objective of this review is to provide an overview regarding the relationship between oxidative stress and AR signaling in the context of PCa and especially CRPC. Additionally, we discuss the potential use of antioxidant therapies in the treatment of PCa.
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Affiliation(s)
- Masaki Shiota
- Department of Urology, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan.
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186
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Decottignies A, d'Adda di Fagagna F. Epigenetic alterations associated with cellular senescence: a barrier against tumorigenesis or a red carpet for cancer? Semin Cancer Biol 2011; 21:360-6. [PMID: 21946622 DOI: 10.1016/j.semcancer.2011.09.003] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2011] [Revised: 09/07/2011] [Accepted: 09/08/2011] [Indexed: 02/03/2023]
Abstract
Cellular senescence is eminently characterized by a permanent cell cycle arrest and the acquisition of morphological, physiological and epigenetic changes. The establishment of cellular senescence can occur in response to telomere attrition associated with cell turnover and ageing or following oncogene activation. Although seemingly two distinct phenomena, cellular senescence and cancer share similarly altered global epigenetic profiles comprising changes in DNA methylation, involving global hypomethylation of repetitive DNA sequences and regional hypermethylation of some gene promoters, and in histone post-translational modifications. As epigenetic and genetic alterations are likely to act synergistically in cancer, anomalous epigenetic marks acquired during ageing or in response to oncogene activation might play important roles in tumorigenesis and cancer progression. These potentially tumor-promoting epigenetic alterations include transcriptional repression of genes encoding tumor suppressors or developmentally regulated proteins, expression of non-coding repetitive RNAs and acquisition of distinct heterochromatin marks that may contribute to suppress cell death by reducing DNA damage response. Cellular senescence may thus be viewed as a double-edged sword that, although acting as a potent anti-proliferative barrier, may pave the way to tumorigenesis in senescence-escaping cells by altering their epigenetic make up.
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Affiliation(s)
- Anabelle Decottignies
- Genetic and Epigenetic Alterations of Genomes, de Duve Institute, Catholic University of Louvain, Brussels, Belgium.
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187
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Reddy JP, Li Y. Oncogene-induced senescence and its role in tumor suppression. J Mammary Gland Biol Neoplasia 2011; 16:247-56. [PMID: 21681694 DOI: 10.1007/s10911-011-9221-5] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/15/2011] [Accepted: 06/07/2011] [Indexed: 01/14/2023] Open
Abstract
While senescence has been known for some time as an inevitable result of repeated DNA replication, oncogene-induced senescence (OIS) represents a relatively new phenomenon. OIS, like apoptosis, has emerged to represent a putative barrier to tumorigenesis in many tissues, including the breast. Here we discuss signals that initiate OIS, evidence for its role in tumor suppression, and mechanisms for its evasion in tumorigenesis.
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Affiliation(s)
- Jay P Reddy
- Department of Molecular & Cellular Biology, Baylor College of Medicine, Houston, TX 77030, USA
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188
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Peña-Rico MA, Calvo-Vidal MN, Villalonga-Planells R, Martínez-Soler F, Giménez-Bonafé P, Navarro-Sabaté À, Tortosa A, Bartrons R, Manzano A. TP53 induced glycolysis and apoptosis regulator (TIGAR) knockdown results in radiosensitization of glioma cells. Radiother Oncol 2011; 101:132-9. [PMID: 21864926 DOI: 10.1016/j.radonc.2011.07.002] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2010] [Revised: 07/04/2011] [Accepted: 07/07/2011] [Indexed: 01/06/2023]
Abstract
BACKGROUND AND PURPOSE The TP53 induced glycolysis and apoptosis regulator (TIGAR) functions to lower fructose-2,6-bisphosphate (Fru-2,6-P(2)) levels in cells, consequently decreasing glycolysis and leading to the scavenging of reactive oxygen species (ROS), which correlate with a higher resistance to cell death. The decrease in intracellular ROS levels in response to TIGAR may also play a role in the ability of p53 to protect from the accumulation of genomic lesions. Given these good prospects of TIGAR for metabolic regulation and p53-response modulation, we analyzed the effects of TIGAR knockdown in U87MG and T98G glioblastoma-derived cell lines. METHODS/RESULTS After TIGAR-knockdown in glioblastoma cell lines, different metabolic parameters were assayed, showing an increase in Fru-2,6-P(2), lactate and ROS levels, with a concomitant decrease in reduced glutathione (GSH) levels. In addition, cell growth was inhibited without evidence of apoptotic or autophagic cell death. In contrast, a clear senescent phenotype was observed. We also found that TIGAR protein levels were increased shortly after irradiation. In addition, avoiding radiotherapy-triggered TIGAR induction by gene silencing resulted in the loss of capacity of glioblastoma cells to form colonies in culture and the delay of DNA repair mechanisms, based in γ-H2AX foci, leading cells to undergo morphological changes compatible with a senescent phenotype. Thus, the results obtained raised the possibility to consider TIGAR as a therapeutic target to increase radiotherapy effects. CONCLUSION TIGAR abrogation provides a novel adjunctive therapeutic strategy against glial tumors by increasing radiation-induced cell impairment, thus allowing the use of lower radiotherapeutic doses.
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Affiliation(s)
- Miguel A Peña-Rico
- Unitat de Bioquímica, Campus de Ciències de la Salut, Institut d’Investigació Biomèdica de Bellvitge-Universitat de Barcelona, Spain
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189
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Luo Y, Zou P, Zou J, Wang J, Zhou D, Liu L. Autophagy regulates ROS-induced cellular senescence via p21 in a p38 MAPKα dependent manner. Exp Gerontol 2011; 46:860-7. [PMID: 21816217 DOI: 10.1016/j.exger.2011.07.005] [Citation(s) in RCA: 80] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2011] [Revised: 07/01/2011] [Accepted: 07/13/2011] [Indexed: 02/07/2023]
Abstract
Oxidative stress induces not only senescence but also autophagy in a variety of mammalian cells. However, the relationship between these two has not been well established and thus, was investigated in the present study using WI38 human diploid fibroblasts (WI38 cells) as a model system. Our results showed that exposure of WI38 cells to H2O2 induced both senescence and autophagy. Downregulation of autophagy protein 5 (Atg5) with Atg5 siRNA inhibited not only autophagy but also senescence induced by H2O2. Further studies showed that Atg5 regulates H2O2-induced senescence primarily by up-regulating the expression of p21 at the level of post-transcription. In addition, we examined the mechanisms by which H2O2 induces autophagy in WI38 cells. Our results revealed that H2O2 increases autophagy independent of the mammalian target of rapamycin (mTOR) negative feedback pathway. Instead, the induction of autophagy by H2O2 depends on the induction of intracellular production of reactive oxygen species (ROS) and activation of the p38 mitogen-activated protein kinase α (p38 MAPKα) pathway.
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Affiliation(s)
- Yi Luo
- Institute of Hematology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
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190
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Prunier C, Masson-Genteuil G, Ugolin N, Sarrazy F, Sauvaigo S. Aging and photo-aging DNA repair phenotype of skin cells-evidence toward an effect of chronic sun-exposure. Mutat Res 2011; 736:48-55. [PMID: 21669211 DOI: 10.1016/j.mrfmmm.2011.05.005] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2010] [Revised: 04/18/2011] [Accepted: 05/07/2011] [Indexed: 12/15/2022]
Abstract
Several studies have demonstrated the deleterious effect of aging on the capacity of cells to repair their DNA. However, current existing assays aimed at measuring DNA repair address only a specific repair step dedicated to the correction of a specific DNA lesion type. Consequently they provide no information regarding the repair pathways that handle other types of lesions. In addition to aging, consequences of photo-exposure on these repair processes remain elusive. In this study we evaluated the consequence of aging and of chronic and/or acute photo-exposure on DNA repair in human skin fibroblasts using a multiplexed approach, which provided detailed information on several repair pathways at the same time. The resulting data were analyzed with adapted statistics/bioinformatics tools. We showed that, irrespective of the repair pathway considered, excision/synthesis was less efficient in non-exposed cells from elderly compared to cells from young adults and that photo-exposure disrupted this very clear pattern. Moreover, it was evidenced that chronic sun-exposure induced changes in DNA repair properties. Finally, the identification of a specific signature at the level of the NER pathway in cells repeatedly exposed to sun revealed a cumulative effect of UVB exposure and chronic sun irradiation. The uses of bioinformatics tools in this study was essential to fully take advantage of the large sum of data obtained with our multiplexed DNA repair assay and unravel the effects of environmental exposure on DNA repair pathways.
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Affiliation(s)
- Chloé Prunier
- Laboratoire Lésions des Acides Nucléiques, Grenoble Cedex 9, France
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191
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Gorospe M, Abdelmohsen K. MicroRegulators come of age in senescence. Trends Genet 2011; 27:233-41. [PMID: 21592610 PMCID: PMC3110060 DOI: 10.1016/j.tig.2011.03.005] [Citation(s) in RCA: 90] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2011] [Revised: 03/24/2011] [Accepted: 03/28/2011] [Indexed: 01/06/2023]
Abstract
Cellular senescence was first reported five decades ago as a state of long-term growth inhibition in viable, metabolically active cells cultured in vitro. However, evidence that senescence occurs in vivo and underlies pathophysiologic processes has only emerged over the past few years. Coincident with this increased knowledge, understanding of the mechanisms that control senescent-cell gene expression programs has also recently escalated. Such mechanisms include a prominent group of regulatory factors (miRNA), a family of small, noncoding RNAs that interact with select target mRNAs and typically repress their expression. Here, we review recent reports that miRNAs are key modulators of cellular senescence, and we examine their influence upon specific senescence-regulatory proteins. We discuss evidence that dysregulation of miRNA-governed senescence programs underlies age-associated diseases, including cancer.
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Affiliation(s)
- Myriam Gorospe
- Laboratory of Molecular Biology and Immunology, NIA-IRP, NIH, 251 Bayview Blvd, Baltimore, MD 21224, USA.
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192
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Hömig-Hölzel C, van Doorn R, Vogel C, Germann M, Cecchini MG, Verdegaal E, Peeper DS. Antagonistic TSC22D1 variants control BRAF(E600)-induced senescence. EMBO J 2011; 30:1753-65. [PMID: 21448135 DOI: 10.1038/emboj.2011.95] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2010] [Accepted: 03/07/2011] [Indexed: 01/05/2023] Open
Abstract
Oncogene-induced cellular senescence (OIS) is an increasingly recognized tumour suppressor mechanism that confines the outgrowth of neoplastic cells in vivo. It relies on a complex signalling network, but only few components have been identified so far. Gene-expression profiling revealed a >100-fold increase in the levels of the transcription factor and putative tumour suppressor gene TGFβ-stimulated clone 22 (TSC22D1) in BRAF(E600)-induced senescence, in both human fibroblasts and melanocytes. Only the short TSC22D1 transcript was upregulated, whereas the abundance of the large protein variant was suppressed by proteasomal degradation. The TSC22D1 protein variants, in complex with their dimerization partner TSC22 homologue gene 1 (THG1), exerted opposing functions, as selective depletion of the short form, or conversely, overexpression of the large variant, resulted in abrogation of OIS. This was accompanied by the suppression of several inflammatory factors and p15(INK4B), with TSC22D1 acting as a critical effector of C/EBPβ. Our results demonstrate that the differential regulation of antagonistic TSC22D1 variants is required for the establishment of OIS and suggest distinct contributions of TSC22 family members to the progression of BRAF(E600)-driven neoplasia.
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Affiliation(s)
- Cornelia Hömig-Hölzel
- Division of Molecular Genetics, The Netherlands Cancer Institute, Amsterdam, The Netherlands
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193
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Jun HJ, Kim S, Dawson K, Choi DW, Kim JS, Rodriguez RL, Lee SJ. Effects of Acute Oral Administration of Vitamin C on the Mouse Liver Transcriptome. J Med Food 2011; 14:181-94. [DOI: 10.1089/jmf.2010.1087] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Affiliation(s)
- Hee-Jin Jun
- Division of Food Bioscience and Technology, College of Life Sciences and Biotechnology, Korea University, Seoul, Republic of Korea
| | - Sukyung Kim
- Division of Food Bioscience and Technology, College of Life Sciences and Biotechnology, Korea University, Seoul, Republic of Korea
| | - Kevin Dawson
- Laboratory for High Performance Computing and Informatics, University of California, Davis, California, USA
| | - Dal-Woong Choi
- Department of Environment and Public Health, College of Health Science, Korea University, Seoul, Republic of Korea
| | - Jong-Sang Kim
- Major in Life and Food Sciences, School of Applied Bioscience, Kyungpook National University, Daegu, Republic of Korea
| | - Raymond L. Rodriguez
- Laboratory for High Performance Computing and Informatics, University of California, Davis, California, USA
| | - Sung-Joon Lee
- Division of Food Bioscience and Technology, College of Life Sciences and Biotechnology, Korea University, Seoul, Republic of Korea
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194
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Abstract
Reactive oxygen species (ROS) and cellular oxidative stress are involved in many physiological and pathophysiological processes, including cellular and organismal aging, migration, proliferation, senescence or death of normal and cancer cells, and stress resistance of stem cells. The forkhead homeobox type O (FOXO) transcription factors FOXO1, FOXO3a, and FOXO4 are critical mediators of the cellular responses to oxidative stress and have been implicated in many of the above ROS-regulated processes. In cancer cells they converge oxidative stress signaling to cell cycle arrest and cell death or promote a motile phenotype. Dependent on their posttranslational modifications FOXOs can also actively regulate the detoxification of cells from ROS and promote stress resistance. Thus, FOXO transcription factors are of vital importance in processes regulating tumor survival or progression, stem cell maintenance, age-related pathological processes, and lifespan extension.
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Affiliation(s)
- Peter Storz
- Department for Cancer Biology, Mayo Clinic, Jacksonville, Florida 32224, USA.
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195
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Abstract
Abstract: In addition to its function as a tumour suppressor, p53 is also involved in
an increasing number of pathology associated with aging. Several activities of p53
appear contribute to its role in aging; one function that might be particularly
relevant in this context is the regulation of senescence. The control of ROS and
senescence by p53 may help to explain how p53 can function to both restrain and
promote aging.
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196
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Guo YL, Chakraborty S, Rajan SS, Wang R, Huang F. Effects of oxidative stress on mouse embryonic stem cell proliferation, apoptosis, senescence, and self-renewal. Stem Cells Dev 2011; 19:1321-31. [PMID: 20092403 DOI: 10.1089/scd.2009.0313] [Citation(s) in RCA: 103] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Oxidative stress, associated with either normal metabolism or disease conditions, affects many cellular activities. Most of our knowledge in this field is derived from fully differentiated cells. Embryonic stem cells (ESCs) have attracted enormous attention for their potential applications in cell therapy, but little is known about how the unique properties of ESCs are affected by oxidative stress. We have investigated the effects of oxidative stress induced by H(2)O(2) on several cellular activities of mouse ESCs. Like differentiated cells, ESCs are sensitive to H(2)O(2)-induced apoptosis when continuously exposed to H(2)O(2) at the concentrations above 150 microM. However, unlike differentiated cells, ESCs are resistant to oxidative stress induced senescence. This is demonstrated by the results that when subjected to a short-term sublethal concentration and duration of H(2)O(2) treatment, fibroblasts enter the senescent state with enlarged flattened cell morphology concurrent with increased expression of senescence marker p21. On the contrary, ESCs neither show any sign of senescence nor express p21. Instead, ESCs enter a transient cell cycle arrest state, but they have remarkable recovery capacity to resume the normal cell proliferation rate without losing the ability of self-renewal and pluripotency. Our results further revealed that H(2)O(2) inhibits cell adhesion and the expression of cyclin D1, which are early events proceeding apoptosis and cell cycle arrest. In conclusion, our data suggest that ESCs are sensitive to H(2)O(2) toxicity, but may have unique mechanisms that prevent H(2)O(2)-induced senescence and protect self-renewal capacity.
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Affiliation(s)
- Yan-Lin Guo
- Department of Biological Sciences, The University of Southern Mississippi, Hattiesburg, Mississippi 39406, USA.
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197
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Lee BC, Gladyshev VN. The biological significance of methionine sulfoxide stereochemistry. Free Radic Biol Med 2011; 50:221-7. [PMID: 21075204 PMCID: PMC3311537 DOI: 10.1016/j.freeradbiomed.2010.11.008] [Citation(s) in RCA: 105] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/05/2010] [Revised: 11/04/2010] [Accepted: 11/05/2010] [Indexed: 12/22/2022]
Abstract
Methionine can be oxidized by reactive oxygen species to a mixture of two diastereomers, methionine-S-sulfoxide and methionine-R-sulfoxide. Both free amino acid and protein-based forms of methionine-S-sulfoxide are stereospecifically reduced by MsrA, whereas the reduction of methionine-R-sulfoxide requires two enzymes, MsrB and fRMsr, which act on its protein-based and free amino acid forms, respectively. However, mammals lack fRMsr and are characterized by deficiency in the reduction of free methionine-R-sulfoxide. The biological significance of such biased reduction of methionine sulfoxide has not been fully explored. MsrA and MsrB activities decrease during aging, leading to accumulation of protein-based and free amino acid forms of methionine sulfoxide. Since methionine is an indispensible amino acid in human nutrition and a key metabolite in sulfur, methylation, and transsulfuration pathways, the consequences of accumulation of its oxidized forms require further studies. Finally, in addition to methionine, methylsulfinyl groups are present in various drugs and natural compounds, and their differential reduction by Msrs may have important therapeutic implications.
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Affiliation(s)
- Byung Cheon Lee
- Division of Genetics, Department of Medicine, Brigham & Women's Hospital and Harvard Medical School, 77 Avenue Louis Pasteur, Boston, MA 02115, USA
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198
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Severin FF, Skulachev VP. Programmed cell death as a target to interrupt the aging program. ADVANCES IN GERONTOLOGY 2011. [DOI: 10.1134/s2079057011010139] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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199
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Makpol S, Abidin AZ, Sairin K, Mazlan M, Top GM, Ngah WZW. gamma-Tocotrienol prevents oxidative stress-induced telomere shortening in human fibroblasts derived from different aged individuals. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2010; 3:35-43. [PMID: 20716926 PMCID: PMC2835887 DOI: 10.4161/oxim.3.1.9940] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
The effects of palm gamma-tocotrienol (GGT) on oxidative stress-induced cellular ageing was investigated in normal human skin fibroblast cell lines derived from different age groups; young (21-year-old, YF), middle (40-year-old, MF) and old (68-year-old, OF). Fibroblast cells were treated with gamma-tocotrienol for 24 hours before or after incubation with IC50 dose of H2O2 for 2 hours. Changes in cell viability, telomere length and telomerase activity were assessed using the MTS assay (Promega, USA), Southern blot analysis and telomere repeat amplification protocol respectively. Results showed that treatment with different concentrations of gamma-tocotrienol increased fibroblasts viability with optimum dose of 80 microM for YF and 40 microM for both MF and OF. At higher concentrations, gamma-tocotrienol treatment caused marked decrease in cell viability with IC50 value of 200 microM (YF), 300 microM (MF) and 100 microM (OF). Exposure to H2O2 decreased cell viability in dose dependent manner, shortened telomere length and reduced telomerase activity in all age groups. The IC50 of H2O2 was found to be; YF (700 microM), MF (400 microM) and OF (100 microM). Results showed that viability increased significantly (p < 0.05) when cells were treated with 80 microM and 40 microM gamma-tocotrienol prior or after H2O2-induced oxidative stress in all age groups. In YF and OF, pretreatment with gamma-tocotrienol prevented shortening of telomere length and reduction in telomerase activity. In MF, telomerase activity increased while no changes in telomere length was observed. However, post-treatment of gamma-tocotrienol did not exert any significant effects on telomere length and telomerase activity. Thus, these data suggest that gamma-tocotrienol protects against oxidative stress-induced cellular ageing by modulating the telomere length possibly via telomerase.
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Affiliation(s)
- Suzana Makpol
- Department of Biochemistry, Faculty of Medicine, National University of Malaysia, Kuala Lumpur, Malaysia.
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200
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Abstract
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. It is being recognized as a critical feature of mammalian cells to suppress tumorigenesis, acting alongside cell death programs. Here, we review the various features of cellular senescence and discuss their contribution to tumor suppression. Additionally, we highlight the power and limitations of the biomarkers currently used to identify senescent cells in vitro and in vivo.
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Affiliation(s)
- Thomas Kuilman
- Division of Molecular Genetics, The Netherlands Cancer Institute, Amsterdam, The Netherlands
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