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Zhong Ya-Hua - - 2008
A relationship between telomeres and radiosensitivity has been established by several studies based on non-mammalian model systems, mouse models, and few human genetic diseases. However, the relationship has not been proven in human carcinoma cells, which have more clinical significance than these other models. The present study aims to determine ...
Subramanian Lakxmi L Department of Biochemistry and Molecular Genetics, University of Illinois at Chicago, 900 S. Ashland Ave., MC669, Chicago, IL 60607, USA. - - 2008
Fission yeast cells survive loss of the telomerase catalytic subunit Trt1 (TERT) through recombination-based telomere maintenance or through chromosome circularization. Although trt1Delta survivors with linear chromosomes can be obtained, they often spontaneously circularize their chromosomes. Therefore, it was difficult to establish genetic requirements for telomerase-independent telomere maintenance. In contrast, when ...
Rózanowski Bartosz - - 2008
The purpose of this study was to determine whether an age-related increase in photoreactivity of human retinal melanosomes (MS) can cause phototoxicity to retinal pigment epithelium (RPE) cells. MS were isolated post mortem from young (20-30 years, young human melanosomes [YHMs]) and old (60-90 years, old human melanosomes [OHMs]) human ...
Churikov Dmitri D Department of Molecular Genetics, Biochemistry and Microbiology, University of Cincinnati College of Medicine, PO Box 0524, Cincinnati, Ohio 45267-0524, - - 2008
Removal of the vertebrate telomere protein Pot1 results in a DNA damage response and cell cycle arrest. Here we show that loss of chicken Pot1 causes Chk1 activation, and inhibition of Chk1 signaling prevents the cell cycle arrest. However, arrest still occurs after disruption of ATM, which encodes another DNA ...
Amrite Aniruddha C AC Department of Pharmaceutical Sciences, University of Nebraska Medical Center, Omaha, Nebraska, - - 2008
Age-related macular degeneration (ARMD) is a leading cause of blindness. The major reason for severe vision loss in ARMD is choroidal neovascularization due to an elevation in the expression of angiogenic factors such as vascular endothelial growth factor (VEGF). Drugs with anti-VEGF and antiproliferative activities can be beneficial for the ...
Burton Dominick G A DG School of Pharmacy and Biomolecular Sciences, Cockcroft Building, University of Brighton, Brighton, East Sussex, BN2 4GJ, - - 2007
The senescence of mitotic cells is hypothesized to play a causal role in organismal aging. Cultures of normal human cells become senescent in vitro as a result of a continuous decline in the mitotic fraction from cell turnover. However, one potential barrier to the evaluation of the frequency and distribution ...
Canudas Silvia S Program in Molecular Pathogenesis and Department of Pathology, The Kimmel Center for Biology and Medicine of the Skirball Institute, New York University School of Medicine, New York, NY 10016, - - 2007
Previous studies in human cells indicate that sister telomeres have distinct requirements for their separation at mitosis. In cells depleted for tankyrase 1, a telomeric poly(ADP-ribose) polymerase, sister chromatid arms and centromeres separate normally, but telomeres remain associated and cells arrest in mitosis. Here, we use biochemical and genetic approaches ...
Dmitrieva Natalia I - - 2007
High extracellular NaCl was previously shown to increase the number of DNA breaks in mammalian cells in tissue culture, renal medullary cells in vivo, C. elegans and marine invertebrates. It was also shown to increase reactive oxygen species in renal cells, resulting in oxidation of proteins and DNA. Cellular senescence ...
Shan Hai-Yan - - 2008
Vascular endothelial cells have a finite cell lifespan and eventually enter an irreversible growth arrest, cellular senescence. The functional changes associated with cellular senescence are thought to contribute to human aging and age-related cardiovascular disorders, e.g. atherosclerosis. In this study, induction of Angiotensin II (Ang II) promoted a growth arrest ...
Liu Qian Q Department of Medicine, New Jersey Medical School, University of Medicine and Dentistry of New Jersey, Newark, NJ 07103, - - 2007
Previous studies have suggested that B cells promote Th2 cell development by inhibiting Th1 cell differentiation. To examine whether B cells are directly required for the development of IL-4-producing T cells in the lymph node during a highly polarized Th2 response, B cell-deficient and wild-type mice were inoculated with the ...
Erenpreisa Jekaterina - - 2007
In the last decade, the concept of "cancer stem cells" has emerged, recognised by the fact that only a small fraction of tumour cells appears to retain the stem cell properties of self-renewal and unlimited proliferation. At the same time, it is well known that cancer is an age-related disease ...
Campisi Judith - - 2007
Cells continually experience stress and damage from exogenous and endogenous sources, and their responses range from complete recovery to cell death. Proliferating cells can initiate an additional response by adopting a state of permanent cell-cycle arrest that is termed cellular senescence. Understanding the causes and consequences of cellular senescence has ...
Bollmann F Mathias - - 2007
Cells lacking aerobic metabolism because of damaged mtDNA accumulate in many postmitotic tissues in the course aging. Although being only a small fraction of cells, they might play a major role in oxidative stress affecting the whole body. However, it remains unclear how such cells, which are under normal circumstances ...
Baerlocher Gabriela M - - 2007
OBJECTIVE: To study if telomere length can be used as a surrogate marker for the mitotic history in normal and affected hematopoietic cells from patients with paroxysmal nocturnal hemoglobinuria (PNH). METHODS: The telomere length was measured by automated multicolor flow fluorescence in situ hybridization in glycosyl-phosphatidyl-inositol anchored protein (GPI)-negative and ...
Baird Duncan M - - 2008
Human telomeres are intrinsically dynamic structures, with multiple biological processes operating to generate substantial length heterogeneity. Processes that operate specifically at the terminus, that include the end-replication problem coupled with C-strand resection, result in gradual telomere erosion with ongoing cell division. Rates of telomere erosion can be modulated by cell ...
Zhao Chang-Qing - - 2007
Intervertebral disc degeneration, which mimics disc aging but occurs at an accelerated rate, is considered to be related to neck or low back pain and disc herniation. Degenerated discs show breakdown of the extracellular matrix and thus fail to bear the daily loadings exerted on the spine. Rather than a ...
Seluanov Andrei A Department of Biology, University of Rochester, Rochester, NY 14627-0211, United - - 2007
Aging is associated with accumulation of genomic rearrangements consistent with aberrant repair of DNA breaks. We have shown previously that DNA repair by non-homologous end joining (NHEJ) becomes less efficient and more error-prone in senescent cells. Here, we show that the levels of Ku70 and Ku80 drop approximately twofold in ...
Vernace Vita A - - 2007
In all cells, protein degradation is a constant, ongoing process that is critical for cell survival and repair. The ubiquitin/proteasome pathway (UPP) is the major proteolytic pathway that degrades intracellular proteins in a regulated manner. It plays critical roles in many cellular processes and diseases. Disruption of the UPP is ...
Davison Glenda Mary - - 2007
Telomeres are DNA structures which serve to stabilize chromosomes. In human cells telomeres progressively shorten with each cell division leading to eventual chromosome instability and cell death. Telomerase is a DNA polymerase which is required for the maintenance of telomeres. Therefore, telomeres and telomerase play a role in the regulation ...
Matulić M - - 2007
Telomeres are among the most important structures in eukaryotic cells. Creating the physical ends of linear chromosomes, they play a crucial role in maintaining genome stability, control of cell division, cell growth and senescence. In vertebrates, telomeres consist of G-rich repetitive DNA sequences (TTAGGG)n and specific proteins, creating a specialized ...
Yan Haifang - - 2007
Senescence or cell death in plant leaves is known to be inducible by darkness or H(2)O(2). When the Arabidopsis gene MAX2/ORE9 is disrupted, leaf senescence or cell death in response to the above stimuli is delayed. Because the rice (Oryza sativa L.) gene DWARF3 (D3) is orthologous to MAX2/ORE9, we ...
Sprung Carl N - - 2007
PURPOSE: To investigate the link between radiosensitivity and telomere length in murine lymphoid cell line stocks that have similar genetic backgrounds but different radiosensitivities. MATERIALS AND METHODS: We used two stocks from both the parental L5,178Y-R cell line and the repair-deficient radiosensitive subline, L5,178Y-S, to assess telomere length. We used ...
Liao Chien-Huang - - 2007
Recombinant fungal immunomodulatory protein, reFIP-gts, was cloned from Ganoderma tsugae and purified. In our previous study, it was shown that reFIP-gts has anti-telomerase effects in A549 cells. Here, we proved that reFIP-gts entry into the cell and localization in endoplasmic reticulum can result in ER stress, thereby increasing ER stress ...
Park Chaehwa - - 2007
Recently, negative effects of phosphatase in tumorigenesis and metastasis have been suggested in various tumor types. In this study, we showed that RhoA activation modulated phosphatase during senescence-like arrest in human prostate cancer cells. Under senescence-inducing condition, decreased Erk phosphorylation was detected in caRhoA-transfected cells and inactivation of Erk, but ...
Pollok S - - 2007
Cell division cycle protein 45 (Cdc45) plays a critical role in DNA replication to ensure that chromosomal DNA is replicated only once per cell cycle. We analysed the expression of human Cdc45 in proliferating and nonproliferating cells. Our findings show that Cdc45 protein is absent from long-term quiescent, terminally differentiated ...
Jennings Paul - - 2007
The nephrotoxic potential of the widely used immunosuppressive agent cyclosporine A (CsA) is well recognized. However, the mechanism of renal tubular toxicity is not yet fully elucidated. Chronic CsA nephropathy and renal organ aging share some clinical features, such as renal fibrosis and tubular atrophy, raising the possibility that CsA ...
Khaw Aik Kia - - 2007
The aim of the present study is to investigate the effect of histone deacetylase inhibitor, trichostatin A (TSA) on the cell growth, apoptosis, genomic DNA damage and the expression of telomerase and associated factors in human normal and brain cancer cells. Here, human normal un-transformed fibroblasts (MRC-5), human normal hTERT-immortalised ...
Aida Junko - - 2007
We developed a novel method for evaluating telomere length in 6 cell types of noncancerous and cancerous mucosal tissues from 11 cases of gastric neoplasm using the quantitative fluorescence in situ hybridization method with telomere and centromere peptide nucleic acid probes. Our telomere length estimates were determined from the background-corrected ...
Sima Ni - - 2007
OBJECTIVE: Human papillomavirus type 16 (HPV-16) is a high-risk DNA tumor virus involved in the development of cervical carcinomas. Substantial studies have demonstrated that E6 and E7 oncoproteins of HPV-16 could induce cell proliferation and immortalization. Repression of E6 and/or E7 oncogenes may induce cervical cancer cells to undergo apoptosis ...
Côté Marceline M Department of Microbiology and Immunology, McGill University, Montreal, - - 2007
The RON receptor tyrosine kinase is a member of the MET proto-oncogene family and is important for cell proliferation, differentiation, and cancer development. Here, we created a series of Madin-Darby canine kidney (MDCK) epithelial cell clones that express different levels of RON, and have investigated their biological properties. While low ...
Stöckl Petra - - 2007
The mitochondrial theory of aging predicts that functional alterations in mitochondria leading to reactive oxygen species (ROS) production contribute to the aging process in most if not all species. Using cellular senescence as a model for human aging, we have recently reported partial uncoupling of the respiratory chain in senescent ...
Antal T T Center for Polymer Studies and Department of Physics, Boston University, Boston, MA 02215, - - 2007
We investigate a model of cell division in which the length of telomeres within a cell regulates its proliferative potential. At each division, telomeres undergo a systematic length decrease as well as a superimposed fluctuation due to exchange of telomere DNA between the two daughter cells. A cell becomes senescent ...
Ferrara Luciana L Department of Biological Sciences, University of Delaware, Delaware Biotechnology Institute, 15 Innovation Way, Newark, DE 19711, - - 2007
We have previously shown that activation of the homologous recombinational repair pathway leads to a block of cell division in corrected cells, possibly through the activity of checkpoint proteins Chk1 and Chk2. In this study, we examine the long-term impact of this stalling on the growth of cells that have ...
Moreau Marielle - - 2007
BACKGROUND AND OBJECTIVES: Cell longevity is linked to sirtuins (silent information regulators), which belong to a family of enzymes implicated in gene silencing, apoptosis, fatty acid metabolism, and regulation of cellular life spans of organisms. Sirtuins are associated with genes that coordinate and optimize the functions of cells as cells ...
Vega Leticia R - - 2007
The Saccharomyces cerevisiae Pif1p helicase is a negative regulator of telomere length that acts by removing telomerase from chromosome ends. The catalytic subunit of yeast telomerase, Est2p, is telomere associated throughout most of the cell cycle, with peaks of association in both G1 phase (when telomerase is not active) and ...
Garbe James C - - 2007
Cultured human mammary epithelial cells (HMEC) encounter two distinct barriers to indefinite growth. The first barrier, originally termed selection, can be overcome through loss of expression of the cyclin-dependent kinase inhibitor p16(INK4A). The resultant p16-, p53+ post-selection HMEC encounter a second barrier, termed agonescence, associated with critically shortened telomeres and ...
Carter Debra A - - 2007
Postmortem adult human retina contains pluripotent progenitor cells capable of forming neurospheres with different retinal cell types. The authors examine whether this is the case at all ages and at different postmortem times. Adult human postmortem retina-derived cell suspensions generated neurospheres in fibroblast growth factor 2 and N2 supplement. The ...
Gupta Neelam - - 2007
We assessed aging in continuous donor skin fibroblast cell line GGM5 up to the 25th passage by in vitro replicative senescence, telomere dynamics and chromosomal abnormalities. Cell proliferation rate increased from 0.84+/-0.26 (primary cells) to 1.20+/-0.17 (13-15 passage group) per day and reduced to 0.65+/-0.14 in 22-25 passages. Cell proliferation ...
Fournier Claudia - - 2007
BACKGROUND AND PURPOSE: The goal of the present study was to investigate aging and genetic instability in the progeny of human fibroblasts exposed to X-rays and carbon ions. MATERIALS AND METHODS: Following irradiation, cells were regularly subcultured until senescence. At selected time-points BrdU-labelling index, expression of cell cycle related proteins, ...
Chung Sylvia A - - 2007
STUDY DESIGN: Nonviral transfection of nucleus pulposus cells with a telomerase expression construct to assess the effects on cellular lifespan, function, karyotypic stability, and transformation properties. OBJECTIVES: To investigate whether telomerase gene therapy can extend the cellular lifespan while retaining functionality of nucleus pulposus cells in a safe manner. SUMMARY ...
Jiao Yangwen - - 2007
Overexpression of human telomere repeat binding factor 2 (TRF2), which may play an important role in the fate of cancer cells, has been observed in adult T-cell leukemia. Previous reports have shown that the inhibition of TRF2 results in the apoptosis of cancer cells. In this study, we demonstrated that ...
Passos João F - - 2007
Aging is an inherently stochastic process, and its hallmark is heterogeneity between organisms, cell types, and clonal populations, even in identical environments. The replicative lifespan of primary human cells is telomere dependent; however, its heterogeneity is not understood. We show that mitochondrial superoxide production increases with replicative age in human ...
Sejersen Henrik - - 2007
Mild stress-induced hormesis is an effective strategy to intervene in the aging process. Repeated exposure of human skin fibroblasts to 41 degrees C heat shock for 1 h twice a week is an example of mild stress that has many hormetic effects, including improved resistance to other stressors. We are ...
Bai XueYuan - - 2007
To investigate the effect of cell cycle inhibitor p14ARF on replicative senescence of human diploid cell, recombinant p19ARF eukaryotic expression vector was constructed and p19ARF gene was transfected into human diploid fibroblasts (WI-38 cells) by liposome-mediated transfection for overexpression. Then, the effects of p19ARF on replicative senescence of WI-38 cells ...
Mehta Ishita S - - 2007
The organization of the genome within interphase nuclei, and how it interacts with nuclear structures is important for the regulation of nuclear functions. Many of the studies researching the importance of genome organization and nuclear structure are performed in young, proliferating, and often transformed cells. These studies do not reveal ...
Liu Dan - - 2007
Although cellular senescence is believed to have a tumor suppressor function, senescent cells have been shown to increase the potential for growth of adjacent cancer cells in animal models. Replicatively senescent human fibroblasts increase the growth of cotransplanted cancer cells in vivo, but the role of cells that have undergone ...
Grafi Gideon - - 2007
Cellular dedifferentiation underlies topical issues in biology such as regeneration and nuclear cloning and has common features in plants and animals. In plants, this process characterizes the transition of differentiated leaf cells to protoplasts (plant cells devoid of cell walls) and is accompanied by global chromatin reorganization associated with reprogramming ...
Yu Li-Rong - - 2007
Telomeres play important functional roles in cell proliferation, cell cycle regulation, and genetic stability, in which telomere length is critical. In this study, quantitative proteome comparisons for the human breast epithelial cells with short and long telomeres (184-hTERTL vs. 184-hTERTS and 90P-hTERTL vs. 90P-hTERTS), resulting from transfection of the human ...
Kitagawa Masae - - 2007
OBJECTIVE: To immortalize human dental pulp (HDP) cell showing stable growth and high mineralization activities in vitro. DESIGN: HDP cells were obtained from a healthy third molar and immortalized by transfection with human telomerase transcriptase (hTERT) gene. To examine the characters of hTERT transfected HDP (HDP-hTERT) cells, we examined expression ...
Jemielity Stephanie - - 2007
Telomere length regulation is an important aspect of cell maintenance in eukaryotes, since shortened telomeres can lead to a number of defects, including impaired cell division. Although telomere length is correlated with lifespan in some bird species, its possible role in aging and lifespan determination is still poorly understood. Here ...
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