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Results 351 - 400 of 1541
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Byun Hae-Ok - - 2009
Induction of premature senescence may be a promising strategy for cancer treatment. However, biomarkers for senescent cancer cells are lacking. To identify such biomarkers, we performed comparative proteomic analysis of MCF7 human breast cancer cells undergoing cellular senescence in response to ionizing radiation (IR). IR-induced senescence was associated with up-regulation ...
Demidenko Zoya N - - 2009
When the cell cycle is arrested but cellular growth is not, then cells senesce, permanently losing proliferative potential. Here we demonstrated that the duration of cell cycle arrest determines a progressive loss of proliferative capacity. In human and rodent cell lines, rapamycin (an inhibitor of mTOR) dramatically decelerated loss of ...
Moon Sung Chae - - 2009
It is known that a close relationship exists among oxidative damage, senescence, and aging. Water dropwort (Ostericum sieboldii Miq. Nakai) and Sedum (Sedum sarmentosum Bunge) are popular green vegetables in Korea and are reported to have strong antioxidative activity. We investigated whether dropwort and Sedum have the potential to prevent ...
Noreen Faiza - - 2009
Human telomerase RNA (hTR) is an intrinsic component of telomerase enzyme. Small interfering RNAs (siRNAs) and single-stranded antisense oligonucleotides have been used previously for silencing of the hTR. The objective of this study was to investigate the effect of partially double-stranded oligodeoxynucleotides (ODNs), in vitro and in vivo in comparison ...
Yuan J - - 2009
These investigations demonstrate that expression of the inhibitor of apoptosis family member, survivin, is dramatically increased during immortalization of nontransformed human fibroblasts that were transduced with telomerase reverse transcriptase (hTERT). Expression of survivin in immortalized fibroblasts peaked during G(2)/M phase of the cell cycle. However, the upregulation of survivin was ...
Modrak David E - - 2009
Bioactive sphingolipids are potent intracellular signaling molecules having profound effects on cell death, growth, and differentiation. Pharmacologic manipulation of sphingolipid levels could have a significant effect on the induction of apoptosis by anticancer agents, and thus, improve treatment efficacy. We observed that gemcitabine cannot completely kill AsPc1 and Panc1 human ...
Jiang Wei-Qin - - 2009
Alternative lengthening of telomeres (ALT) is a recombination-mediated process that maintains telomeres in telomerase-negative cancer cells. In asynchronously dividing ALT-positive cell populations, a small fraction of the cells have ALT-associated promyelocytic leukemia nuclear bodies (APBs), which contain (TTAGGG)n DNA and telomere-binding proteins. We found that restoring p53 function in ALT ...
Charruyer Alexandra - - 2009
Aged epidermis is less proliferative than young, as exemplified by slower wound healing. However, it is not known whether quantitative and/or qualitative alterations in the stem and/or transit-amplifying (TA) compartments are responsible for the decreased proliferation. Earlier studies found a normal or decreased frequency of putative epidermal stem cells (EpiSCs) ...
Liao Wei-Li - - 2009
PURPOSE: Senescence of retinal pigment epithelial (RPE) cells is a crucial event in the pathogenesis of age-related macular degeneration (AMD). This study was designed to improve the understanding of proteomic changes that underlie RPE senescence. Specifically, the levels of several protein fragments in prematurely senescent ARPE-19 cells were quantitatively compared ...
Dabrowska Magdalena - - 2009
Human colorectal adenocarcinoma C85 cells, treated with high dose methotrexate (1 microM; IC(50)=51 nM), undergo accelerated senescence, as the cells (i) are growth arrested at the G(1) and S phases of the cell cycle, (ii) are SA-beta-galactosidase-positive, (iii) show induced expression of p21(waf1/cip1) and decreased expression of p16(INK4a), and (iv) ...
Saretzki Gabriele - - 2009
Telomerase plays an important role in cellular proliferation capacity and survival under conditions of stress. A large part of this protective function is due to telomere capping and maintenance. Thus it contributes to cellular immortality in stem cells and cancer. Recently, evidence has accumulated that telomerase can contribute to cell ...
Humbert Nicolas N UMR8161, Institut de Biologie de Lille, Centre National de la Recherche Scientifique/Universités de Lille 1-2/Institut Pasteur de Lille, IFR142, Lille, - - 2009
Normal cell growth can be permanently blocked when cells enter a state known as senescence. This phenomenon can be triggered by various stresses, such as replicative exhaustion, oncogenic stimulation, or oxidative stress. Senescence prevents transmission of aberrant signals to daughter cells and thus prevents irreversible damage that could favor cancer ...
Shervington Amal - - 2009
Cancer stem cells (CSCs) are a minute sub-population of self-renewing, immortal cells, which can be responsible for chemoresistance observed in the treatment of cancer. CSCs are similar to cancer cells requiring telomerase activity or alternative mechanisms for their proliferation and regeneration. This study explored the correlation between CD133 (stem cell ...
Chen Ying Y Department of Environmental Health and Center for Environmental Genetics, University of Cincinnati Medical Center, Cincinnati, OH 45267-0056, USA. - - 2009
Cellular senescence is the irreversible entry of cells into growth arrest. Senescence of primary cells in culture has long been used as an in vitro model for aging. Glutamate-cysteine ligase (GCL) controls the synthetic rate of the important cellular antioxidant glutathione (GSH). The catalytic subunit of GCL, GCLC, is catalytically ...
Miri-Moghaddam E - - 2009
Telomerase is a ribonucleoprotein complex. It consists of two main components, human telomerase reverse transcriptase (hTERT) and human telomerase RNA. High telomerase activity is present in most malignant cells, but it is barely detectable in majority of somatic cells. The direct correlation between telomerase reactivation and carcinogens has made hTERT ...
De Vos Winnok H - - 2009
Telomeres are complex end structures that confer functional integrity and positional stability to human chromosomes. Despite their critical importance, there is no clear view on telomere organization in cycling human cells and their dynamic behavior throughout the cell cycle. We investigated spatiotemporal organization of telomeres in living human ECV-304 cells ...
Jain Neena N Department of Medicine, Albert Einstein College of Medicine, 1300 Morris Park Ave., Bronx, NY 10461, - - 2009
Although several virulence factors and associated genes have been identified, the mechanisms that allow Cryptococcus neoformans to adapt during chronic infection and to persist in immunocompromised hosts remain poorly understood. Characterization of senescent cells of C. neoformans demonstrated that these cells exhibit a significantly enlarged cell body and capsule but ...
Wijeratne Subhashinee S K SS Department of Nutrition and Health Sciences, University of Nebraska at Lincoln, Lincoln, NE 68583-0806, - - 2010
Covalent modifications of histones play a role in regulating telomere attrition and cellular senescence. Biotinylation of lysine (K) residues in histones, mediated by holocarboxylase synthetase (HCS), is a novel diet-dependent mechanism to regulate chromatin structure and gene expression. We have previously shown that biotinylation of K12 in histone H4 (H4K12bio) ...
Zeng Sicong S Department of Radiation Oncology, Washington University School of Medicine, 4511 Forest Park, St. Louis, MO 63108, - - 2009
Telomerase-negative cancer cells maintain their telomeres through the alternative lengthening of telomeres (ALT) pathway. Although a growing body of evidence demonstrates that the ALT mechanism is a post-replicative telomere recombination process, molecular details of this pathway are largely unknown. Here we demonstrate that MUS81, a DNA structure specific recombination endonuclease, ...
Santarosa Manuela - - 2009
BRCA1-associated tumors are characterized by an elevated genomic instability and peculiar expression profiles. Nevertheless, tailored treatments for BRCA1 mutation carriers have only been partially investigated up to now. The implementation of therapeutic strategies specific for these patients has been in part hindered by the paucity of proper preneoplastic and neoplastic ...
Liu Jinglan - - 2010
We have previously shown by chromosome transfer technique that chromosome 6 alters the phenotype of a variety of tumour cells and SV40 immortalized cells. We present here the phenotypic effects of the ectopic expression of RNaseT2, a highly conserved ribonuclease encoded by chromosome 6q27, in SV40 immortalized cell lines. We ...
Cooley Carol - - 2009
The telomere end-protection complex prevents the ends of linear eukaryotic chromosomes from degradation or inappropriate DNA repair. The homodimeric double-stranded DNA-binding protein, Trf1, is a component of this complex and is essential for mouse embryonic development. To define the requirement for Trf1 in somatic cells, we deleted Trf1 in chicken ...
Tchougounova E - - 2009
SOX5 is a member of the high-mobility group superfamily of architectural non-histone proteins involved in gene regulation and maintenance of chromatin structure in a wide variety of developmental processes. Sox5 was identified as a brain tumor locus in a retroviral insertional mutagenesis screen of platelet-derived growth factor B (PDGFB)-induced mouse ...
Takahashi Akira - - 2009
OBJECTIVE: Progesterone receptor (PR) expression is a favorable prognostic marker in ovarian cancer. We previously demonstrated that the induction of PR-B by treatment with cAMP was associated with G0/G1 arrest of the cell cycle and growth inhibition in NIH 3T3 cells. In this study, we examined the effect of cAMP ...
Mishra, Vijendra Kumar
Telomerase, a potential marker for tumorigenesis, has been found to be activated in more than 85-90% of human cancer. Curcumin is the major biologically active, yellow phytochemical compound of Curcuma longa (Zingiberaceae). The present study is aimed to investigate the capacity of curcumin on the regulation of telomerase activity and ...
Chien Chih-Chiang - - 2009
In the present study, the roles of telomerase and prostaglandin E(2) (PGE(2)) in platelet-derived growth factor (PDGF's) and fibroblast growth factor-2 (FGF-2's) effects against C(2)-ceramide-induced cell death were investigated. C(2)-ceramide reduced the viability of NIH3T3 cells in a condition without calf serum (CS) in accordance with decreasing telomerase activity according ...
Huang Sheng-Teng - - 2009
BACKGROUND: This study was designed to obtain the chemical fingerprint and to investigate the effect of Phyllanthus urinaria on telomerase activity and apoptotic pathways in the human nasopharyngeal carcinoma cell line (NPC-BM1). MATERIALS AND METHODS: The polyphenol compounds in P. urinaria were investigated by HPLC/MS. Cell viability with the treatment ...
Lian Xian Jin - - 2009
Very little is known as to how the accumulation of senescent cells during aging may affect our ability to cope with various stresses. Here we show that the assembly of stress granules (SGs) is part of the early events used by senescent cells to respond to certain stresses. Although SGs ...
Gosselin Karo - - 2009
Normal cells reach senescence after a specific time and number of divisions, leading ultimately to cell death. Although escape from this fate may be a requisite step in neoplastic transformation, the mechanisms governing senescent cell death have not been well investigated. We show here, using normal human epidermal keratinocytes, that ...
Zhao Xiangshan X Department of Genetics, Eppley Institute for Cancer and Allied Diseases and UNMC-Eppley Cancer Center, University of Nebraska Medical Center, Omaha, Nebraska 68198, - - 2009
Rho family small GTPases serve as molecular switches in the regulation of diverse cellular functions, including actin cytoskeleton remodeling, cell migration, gene transcription, and cell proliferation. Importantly, Rho overexpression is frequently seen in many carcinomas. However, published studies have almost invariably used immortal or tumorigenic cell lines to study Rho ...
Li Shang S Department of Biochemistry and Biophysics, University of California, San Francisco, Box 2200, San Francisco, CA 94143-2200, - - 2009
Elongation of telomeres by telomerase replenishes the loss of terminal telomeric DNA repeats during each cell cycle. In budding yeast, Cdc13 plays an essential role in telomere length homeostasis, partly through its interactions with both the telomerase complex and the competing Stn1-Ten1 complex. Previous studies in yeast have shown that ...
Fan Qiang - - 2009
Both Fanconi anemia (FA) and telomere dysfunction are associated with chromosome instability and an increased risk of cancer. Because of these similarities, we have investigated whether there is a relationship between the FA protein, FANCD2 and telomeres. We find that FANCD2 nuclear foci colocalize with telomeres and PML bodies in ...
Yang Yunshan - - 2009
Xerophilusin B (XB), macrocalin B (MB) and eriocalyxin B (EB) belong to ent-kaurene diterpenoids. The inhibition effects of three ent-kaurane compounds on the proliferation of six tumour lines (K562, HL-60, A549, MKN, HCT and CA) were estimated by methyl-thiazol-tetrazolium, and the telomerase activity in K562 cells was measured by the ...
Valtink Monika - - 2009
The retinal pigment epithelium (RPE) is a monolayer of cells adjacent to the photoreceptors of the retina. It plays a crucial role in maintaining photoreceptor health and survival. Degeneration or dysfunction of the RPE can lead to photoreceptor degeneration and as a consequence to visual impairment. The most common diseased ...
Lamm Noa - - 2009
BACKGROUND: Eukaryotic chromosomes end with telomeres, which in most organisms are composed of tandem DNA repeats associated with telomeric proteins. These DNA repeats are synthesized by the enzyme telomerase, whose activity in most human tissues is tightly regulated, leading to gradual telomere shortening with cell divisions. Shortening beyond a critical ...
Chen Dan - - 2009
Squamous cell carcinomas are the leading frequent malignant tumors in the oral and maxillofacial region. Currently available treatment options are of limited efficacy, and there is an urgent need for development of alternative therapies. RNA interference (RNAi) is a sequence-specific RNA degradation process. In this study, we screened and identified ...
Suhr Steven T - - 2009
Human induced pluripotent stem cells (IPSCs) have enormous potential in the development of cellular models of human disease and represent a potential source of autologous cells and tissues for therapeutic use. A question remains as to the biological age of IPSCs, in particular when isolated from older subjects. Studies of ...
Temime-Smaali Nassima - - 2009
In Alternative Lengthening of Telomeres (ALT) cell lines, specific nuclear bodies called APBs (ALT-associated PML bodies) concentrate telomeric DNA, shelterin components and recombination factors associated with telomere recombination. Topoisomerase IIIalpha (Topo III) is an essential telomeric-associated factor in ALT cells. We show here that the binding of Topo III to ...
Liggett Thomas E - - 2009
The Retinal Pigmented Epithelium (RPE) is juxtaposed with the photoreceptor outer segments of the eye. The proximity of the photoreceptor cells is a prerequisite for their survival, as they depend on the RPE to remove the outer segments and are also influenced by RPE cell paracrine factors. RPE cell death ...
Steffen Kristan K - - 2009
Aging is a degenerative process characterized by a progressive deterioration of cellular components and organelles resulting in mortality. The budding yeast Saccharomyces cerevisiae has been used extensively to study the biology of aging, and several determinants of yeast longevity have been shown to be conserved in multicellular eukaryotes, including worms, ...
Zhang Xue-Mei - - 2009
A novel population of cells that express typical immature neuronal markers including doublecortin (DCX+) has been recently identified throughout the adult cerebral cortex of relatively large mammals (guinea pig, rabbit, cat, monkey and human). These cells are more common in the associative relative to primary cortical areas and appear to ...
Ozturk Mehmet - - 2009
Cellular senescence is a process leading to terminal growth arrest with characteristic morphological features. This process is mediated by telomere-dependent, oncogene-induced and ROS-induced pathways, but persistent DNA damage is the most common cause. Senescence arrest is mediated by p16(INK4a)- and p21(Cip1)-dependent pathways both leading to retinoblastoma protein (pRb) activation. p53 ...
Marie-Egyptienne Delphine T - - 2009
Cellular viability requires telomere maintenance, which, in mammals, is mainly mediated by the reverse transcriptase telomerase. Telomerase core components are a catalytic subunit TERT and an RNA subunit TR (hTR in humans, mTR in mouse) that carries the template to generate telomeres de novo. Telomere dysfunction can lead to senescence ...
Hansson Maire - - 2008
CONTEXT: We previously found telomere repeat amplification protocol (TRAP) in situ helpful in the diagnosis of malignancy in effusions, whereas varying sensitivities and specificities for malignancy were reported by investigators using extract-based TRAP. OBJECTIVE: To compare the 2 methods and to elucidate the discrepancies between them. DESIGN: Twenty-three effusions were ...
di Domenico Enea Gino - - 2009
In this work we report that budding yeasts carrying human-type telomeric repeats at their chromosome termini show a chronic activation of the Rad53-dependent DNA damage checkpoint pathway and a G2/M cell cycle delay. Furthermore, in the absence of either TEL1/ATM or MEC1/ATR genes, which encodes phosphatidylinositol 3-kinase-related kinases (PIKKs), we ...
Joseph James A - - 2008
Research indicates that muscarinic receptors (MAChRs) may show selective declines in sensitivity during aging and Alzheimer's disease (AD), and these decrements may be related to oxidative stress sensitivity. M1AChR - transfected COS-7 cells exhibit greater decrements in Ca;{2+} buffering following oxotremorine-induced depolarization than M3 cells. This loss, induced via dopamine ...
Demidenko Zoya N - - 2008
We tested a hypothesis that activation of growth-promoting pathways is required for cellular senescence. In the presence of serum, induction of p21 caused senescence, characterized by beta-Galactosidase staining, cell hypertrophy, increased levels of cyclin D1 and active TOR (target of rapamycin, also known as mTOR). Serum starvation and rapamycin inhibited ...
Phipps Sharla M O SM Department of Biology, University of Alabama at Birmingham, 175 Campbell Hall, 1300 University Boulevard, Birmingham, AL 35294-1170, - - 2009
Although the progression of aging and the diseases associated with it are extensively studied, little is known about the initiation of the aging process. Telomerase is down-regulated early in embryonic differentiation, thereby contributing to telomeric attrition and aging. The mechanisms underlying this inhibition remain elusive, but epigenetic studies in differentiating ...
Lee Jooeun - - 2009
Shortened telomeres are a normal consequence of cell division. However, telomere shortening past a critical point results in cellular senescence and death. To determine the effect of telomere shortening on lung, four generations of B6.Cg-Terc(tm1Rdp) mice, null for the terc component of telomerase, the holoenzyme that maintains telomeres, were bred ...
Henderson Kiersten A KA Division of Basic Sciences, Fred Hutchinson Cancer Research Center, 1100 Fairview Avenue North, P.O. Box 19024, Seattle, WA 98109, - - 2008
Individual cells of the budding yeast, Saccharomyces cerevisiae, have a limited life span and undergo a form of senescence termed replicative aging. Replicative life span is defined as the number of daughter cells produced by a yeast mother cell before she ceases dividing. Replicative aging is asymmetric: a mother cell ...
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