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Zucchero Theresa - - 2006
Human lifespan is limited by aging of both mitotic and post-mitotic cells. These two forms of aging may occur by distinct or overlapping mechanisms. Telomere erosion has been shown to limit the proliferative lifespan of human somatic cells. Other vertebrates, such as mice, possess robust telomerase activity in most cell ...
Cei Silvia - - 2006
AIM: To establish whether within an autograft ageing has an impact on the number of cells capable of responding to growth and differentiation factors released at defect sites. MATERIAL AND METHODS: The number of cells that grow out from calvarial and mandibular explants of rats 6 weeks and 9 months ...
Dyson Janet - - 2007
We analyse an age-structured model of telomere loss in a proliferating cell population. The cell population is divided into telomere classes, which shorten each round of division. The model consists of a nonlinear system of partial differential equations for the telomere classes. We prove that if the highest telomere class ...
<span style="font-style: italic;">B. paxillifera</span> is a pennate diatom with a rectangular cell shape that can form&nbsp; colonies with adjacent cells sliding along each other. They can therefore occur as long extended 'chains' or ribbon arrays
Ivanković Milena - - 2007
Normal human somatic cells in culture have a limited dividing potential. This is due to DNA end replication problem, whereby telomeres shorten with each subsequent cell division. When a critical telomere length is reached cells enter senescence. To overcome this problem, immortal HeLa cell line express telomerase, an enzyme that ...
Murofushi Yoshiteru - - 2006
Based on the finding that telomerase is reactivated solely in cancer cells, the human telomerase reverse transcriptase (hTERT) promoter has recently been used to target cancer cells by gene therapy. The recent, surprising observation that telomerase is physiologically activated even in normal somatic cells during S-phase has raised concerns as ...
Wang Xinwen - - 2006
DNA tumor viruses such as SV40, Ras and papillomaviruses are the most commonly used agents in immortalization of non-hematopoietic cells, but the results are quite different. Some of them even lead instead to a senescence-like state. To verify the potential of SV40 T antigen-mediated immortalization or properties and functions of ...
Fridman Aviva Levine - - 2006
Abrogation of cellular senescence, resulting in immortalization, is a necessary step in the tumorigenic transformation of a cell. Four independent, spontaneously immortalized Li-Fraumeni syndrome (LFS) cell lines were used to analyze the gene expression changes that may have given these cell lines the growth advantage required to become immortal. A ...
Zamolo Gordana - - 2007
Telomerase is a ribonucleoprotein reverse transcriptase which RNA component (TERC) and reverse transcriptase (TERT) function together to elongate telomeres. If cells are to survive and proliferate indefinitely, telomere preservation is essential for the immortalization process. Somatic cells rarely possess TA, but over 90% of tumor cells express active telomerase. Increased ...
Fujiwara Masachika - - 2006
Telomere maintenance can occur in the absence of telomerase by a mechanism referred to as alternative lengthening of telomeres (ALT). ALT is considered to be rare in tumors of epithelial origin. The biological significance and molecular mechanism of ALT have not been well studied in human cancers. It has been ...
de Souza Nascimento Patrícia - - 2006
Human telomerase is a ribonucleoprotein complex composed of at least the reverse catalytic transcriptase hTERT and RNA component hTR. The enzyme stabilizes telomere length and thereby contributes to unlimited cell proliferation, i.e. immortality. Reactivation of telomerase activity during carcinogenesis is a common hallmark in most human tumor types. Consequently, telomerase ...
Schmitt Annett - - 2006
Advanced glycation end products (AGEs) that arise from the reaction of sugars with protein side chains and the terminal amino group are supposed to be involved in the pathogenesis of several diseases and therefore the effects of AGEs on cells are the objective of numerous investigations. The effects of AGEs ...
Yang Gong - - 2007
Ovarian cancer is developed from a single layer of thin epithelial cells covering the surface of ovary, named human ovarian surface epithelial cells. Like all primary human cells, human ovarian surface epithelial cells have a finite life span and will go into senescence and eventually die when cultured in vitro. ...
Wang Yun-Feng YF Department of General Surgery, The Center Hospital of Shanghai Yangpu District (Branch Hospital of the Affiliated Xinhua Hospital of Shanghai Jiaotong University), Shanghai 200127, China. - - 2006
To investigate the effect of telomerase hTERT gene antisense oligonucleotide (hTERT-ASO) on proliferation and telomerase activity of pancreatic cancer cell line Bxpc-3. MTT assay was used to detect the effect of different doses of hTERT-ASO on proliferation of Bxpc-3 cell for different times. To study the anti-tumor activity, the cells ...
Minois Nadège - - 2006
Theories of the evolution of senescence state that symmetrically dividing organisms do not senesce. However, this view is challenged by experimental evidence. We measured by immunofluorescence the occurrence and intensity of protein carbonylation in single and symmetrically dividing cells of Schizosaccharomyces pombe. Cells of S. pombe show different levels of ...
Tadokoro Tomomi - - 2006
Human diploid fibroblastic cell line, TIG-3, has a finite life span of about 80 population doubling levels (PDL), and is used for in vitro aging studies. Young cells (PDL 23) grew to higher cell densities at a higher growth rate than aged cells (PDL 77). When the electrophoretic mobility of ...
Walen Kirsten H - - 2006
Previously, it was found that senescent cells can undergo a modified cell cycle with mitotic cells as the end results. The major cycling events started with polyploidization, followed by depolyploidization to multinucleated cells (MNCs). These latter cells produced mononuclear offspring cells that could express mitotic cell divisions. In this report ...
Liu Yang - - 2006
We identified a series of immunodominant and subdominant epitopes from alpha fetoprotein (AFP), restricted by HLA-A*0201, which are recognized by the human T cell repertoire. The four immunodominant epitopes have been tested for immunogenicity in vivo, in HLA-A*0201+AFP+ advanced stage hepatocellular cancer (HCC) patients, and have activated and expanded AFP-specific ...
Roberts S - - 2006
Intervertebral discs demonstrate degenerative changes relatively early in life. Disc degeneration, in turn, is associated with back pain and disc herniation, both of which cause considerable clinical problems in the western world. Cell senescence has been linked to degenerative diseases of other connective tissues such as osteoarthritis. Thus we investigated ...
Wang Yan-ling - - 2006
Placental trophoblast cells are unique endocrine cells that play vital roles during the processes of embryonic implantation and placentation. However, research into the function of human trophoblast has been largely restrained mainly due to a lack of adequate cell models. A normal placenta-origin cytotrophoblast cell line (NPC) was previously established ...
Won Jaejoon - - 2006
Most somatic cells encounter an inevitable destiny, senescence. Little progress has been made in identifying small molecules that extend the finite lifespan of normal human cells. Here we show that the intrinsic 'senescence clock' can be reset in a reversible manner by selective modulation of the ataxia telangiectasia-mutated (ATM) protein ...
Mizukoshi Eishiro - - 2006
Human telomerase reverse transcriptase, hTERT, has been identified as the catalytic enzyme required for telomere elongation. hTERT is expressed in most tumor cells but seldom expressed in most human adult cells. It has been reported that 80% to 90% of hepatocellular carcinomas (HCCs) express hTERT, making the enzyme a potential ...
Cukusić A - - 2006
Normal human somatic cells have a limited division potential when they grow in vitro. It is believed that shortening of telomeres, specialized structures at the ends of chromosomes, controls cell growth. When one telomere achieves a critical minimal length, the cell cycle control mechanism recognizes it as DNA damage and ...
Zou Lin - - 2006
OBJECTIVES: To study the effects and possible mechanisms of mitosis arrest deficiency 1 (Mad1), the heterodimerizer of Max and a transcriptional repressor, on cell proliferation of bladder cancer in vitro and in vivo. METHODS: Combining methyl thiazolyl tetrazolium (MTT) assay, flow cytometry, luciferase assay, telomeric repeat amplification protocol-enzyme-linked immunosorbent assay, ...
Cheng Hsueh-Ling - - 2006
It was attempted in this work to establish a cell line in which senescent cells can be readily and directly identified in situ in live culture. Transcriptional activation of p21(Cip1/Waf1) gene is known to be one of the key steps in the development of cellular senescence, whereas the elements within ...
Ohshima Susumu - - 2006
To study the role of cell death in the aging process, cell death during spontaneous cellular senescence in vitro was examined with normal human fibroblasts. A small subset of the senescent cells showed aberrant morphology such as remarkable nuclear fragmentation or multiple micronuclei, and such cells often showed positive reactions ...
Katakura Yoshinori - - 2006
Although dysfunctional telomeres and oncogenic or stressful stimuli are known to trigger cellular senescence in normal human diploid cells, the molecules and signaling network involved in the cellular senescence program are not fully understood. We have been trying to identify cellular senescence-inducing factors by various means. First, we screened for ...
Davis Terence - - 2006
In the Werner syndrome (WS) fibroblasts have an increased life span and growth rate when treated with the p38 inhibitor SB203580. Additionally, the cellular morphology reverts to that seen in young normal fibroblasts. The p38 pathway is activated in young WS cells, associated with high levels of p21(WAF1) leading to ...
Edqvist Anna - - 2006
Elevated telomerase activity is an important molecular signature of cancer cells and primitive cells in regenerative tissues. However, isolation of single living cells with endogenous telomerase activity has not yet been possible. Here, we developed adenovirus serotype 35 tropism-based vectors encoding destabilized enhanced green fluorescence protein with a half-life of ...
Bartling Babett - - 2006
Epithelial-mesenchymal interactions contribute to functionality and integrity of the lung epithelium, which might change during ageing and associated cellular ageing. Therefore, we studied the effect of senescent versus pre-senescent lung fibroblasts (WI-38) on mitogenic and stress-protective factors in lung epithelial cells (H358). By use of conditioned medium, we found a ...
Vaughan Melville B - - 2006
A therapeutic approach being investigated for a variety of pathologies is tissue regeneration using a patient's own cells. Such studies have been hampered due to the difficulty in growing epithelial cells for prolonged periods in culture. Replicative senescence due to short telomeres and p16 induced by culture stress work together ...
Alge Claudia S - - 2006
Functional research of retinal pigment epithelium (RPE) most often relies on utilization of RPE-derived cell lines in vitro. However, no studies about similarities and differences of the respective cell lines exist so far. Thus, we here analyze the proteome of the most popular RPE cell lines: ARPE-19 and hTERT and ...
Cell broadest rougly in the middle, posteriorly ending in a blunt antapex, length 56-70 microns.
Chang Ue-Min - - 2006
Ganoderiol F (GolF), a tetracyclic triterpene, was isolated from Ganoderma amboinense and found to induce senescence of cancer cell lines. GolF induced growth arrest of cancer cell lines HepG2, Huh7 and K562, but exerted much less effect in hepatoma Hep3B cells and normal lung fibroblast MRC5 cells, and no effect ...
Ide Nagatoshi - - 2006
Elevated plasma homocysteine (Hcy) levels have been recognized as an independent risk factor for atherosclerotic vascular disease. During formation of early atherosclerotic lesions, expression of CD36, a class B scavenger receptor on macrophages, is crucially involved in the uptake of oxidized low-density lipoprotein (OxLDL) and foam-cell formation. We therefore determined ...
Matsuura Nariaki - - 2006
Because colorectal cancer is likely to develop in many people at some point during their lives, prevention has become a high priority. Diet and nutrition play an important role during the multistep colon carcinogenic process. Garlic has been traditionally used as a spice and is well known for its medicinal ...
McClintock Dayle - - 2006
Hutchinson-Gilford progeria syndrome (HGPS; Online Mendelian Inheritance in Man accession no. 176670) is a rare disorder that is characterized by segmental premature aging and death between 7 and 20 years of age from severe premature atherosclerosis. Mutations in the LMNA gene are responsible for this syndrome. Approximately 80% of HGPS ...
Lee Jeeyun - - 2006
Lovastatin inhibits a 3-hydroxy 3-methylglutaryl coenzyme A reductase and prevents the synthesis of cholesterol precursors, such as farnesyl pyrophosphate (FPP) and geranylgeranyl pyrophosphate (GGPP), responsible for important cell signaling in cell proliferation and migration. Recently, the anti-cancer effect of lovastatin has been suggested in various tumor types. In this study, ...
Nishiyama Atsuya - - 2006
Telomeres are regulated by a homeostatic mechanism that includes telomerase and telomeric repeat binding proteins, TRF1 and TRF2. Recently, it has been hypothesized that telomeres assume distinct configurations in a cell-cycle-dependent manner, although direct biochemical evidence is lacking. Here we demonstrated that Xenopus TRF1 (xTRF1) associates with telomere chromatin specifically ...
Russo Valentina - - 2006
Telomerase is crucial for chromosome stability because it maintains telomere length. Little is known about telomerase in ovarian follicles, where an intense cell division is crucial to sustain estrous cycle and to drive oocyte development. The present research was performed to detect, by immunohistochemistry, the distribution of telomerase catalytic subunit ...
Voglauer Regina - - 2006
In a recent screening for genes down regulated in replicatively senescent human umbilical vein endothelial cells (HUVECs), we have isolated the novel protein SNEV. Since then SNEV has proven as a multifaceted protein playing a role in pre-mRNA splicing, DNA repair, and the ubiquitin/proteosome system. Here, we report that SNEV ...
Kwak Sungwook - - 2006
Using normal swine kidney epithelial (SKE) cells that were shown to be senescent at passages 12 to 14, we have established one lifespan-extended cell line and two lifespan-extended cell lines by exogenous introduction of the human catalytic subunit of telomerase (hTERT) and simian virus 40 large T-antigen (SV40LT), all of ...
Greider C W - - 2006
Small functional RNAs play essential roles in many biological processes. Regulating the level of these small RNAs can be as important as maintaining their function in cells. The telomerase RNA is maintained in cells at a steady-state level where small changes in concentration can have a profound impact on function. ...
Xu Tao - - 2006
In order to study the effects of dominant negative human telomerase reverse transcriptase (DN-hTERT) on cell growth and telomerase activity in osteosarcoma cell line MG63, MG63 cells were transfected with DN-hTERT-IRES2-EGFP9 (DN) or IRES2-EGF (I, blank vector) with lipofectamine 2000. The stably transfected cells were selected with G-418. Cell growth ...
Krikun Graciela - - 2006
The loss of replicative potential with each cell division has been attributed to the progressive shortening of telomeres. This "mitotic clock" occurs because most normal human cells are telomerase-negative. Telomerase is a multicomponent enzyme that prevents loss of telomeric DNA associated with normal cell division. Transfection of cells with vectors ...
Velasco-Velázquez Marco A - - 2006
Gentamicin (GM)-induced nephrotoxicity limits the use of this antibiotic. It has been shown that aged garlic extract (AGE) and S-allylcysteine (SAC), the most abundant organosulfur compound in AGE, ameliorate GM-induced nephrotoxicity in rats. The present communication evaluated the effect of AGE and SAC on proliferation and on GM-induced toxicity and ...
Hertzog Radu G - - 2006
Like cells, all mammals have a limited life span. Among cells there are a few exceptions (e.g., immortal cells), among mammals not, even if some of them live longer. Many in vitro and in vivo studies support the consensus that telomere length is strongly correlated with life span. At the ...
Passos João F - - 2006
The mitochondrial theory of aging remains to date one of the most popular theories of aging. One major model of aging is replicative senescence, where the irreversible loss of division potential of somatic cells occurs after a more or less constant number of cell divisions. Few data are available concerning ...
Zhang Lili - - 2006
The cellular response to telomere dysfunction in plants was investigated with the use of telomestatin, an inhibitor of human telomerase activity. Telomestatin bound to plant telomeric repeat sequence, and inhibited telomerase activity in suspension-cultured cells of Arabidopsis thaliana and Oryza sativa (rice) in a dose-dependent manner. The inhibitor did not ...
Tomlinson Rebecca L - - 2006
Telomerase synthesizes telomeres at the ends of human chromosomes during S phase. The results presented here suggest that telomerase activity may be regulated by intranuclear trafficking of the key components of the enzyme in human cells. We examined the subcellular localization of endogenous human telomerase RNA (hTR) and telomerase reverse ...
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