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Blasiak J, Szczepanska J, Fila M, Pawlowska E, Kaarniranta K. Potential of Telomerase in Age-Related Macular Degeneration-Involvement of Senescence, DNA Damage Response and Autophagy and a Key Role of PGC-1α. Int J Mol Sci 2021; 22:ijms22137194. [PMID: 34281248 PMCID: PMC8268995 DOI: 10.3390/ijms22137194] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2021] [Revised: 06/29/2021] [Accepted: 07/01/2021] [Indexed: 02/07/2023] Open
Abstract
Age-related macular degeneration (AMD), the main cause of vision loss in the elderly, is associated with oxidation in the retina cells promoting telomere attrition. Activation of telomerase was reported to improve macular functions in AMD patients. The catalytic subunit of human telomerase (hTERT) may directly interact with proteins important for senescence, DNA damage response, and autophagy, which are impaired in AMD. hTERT interaction with mTORC1 (mTOR (mechanistic target of rapamycin) complex 1) and PINK1 (PTEN-induced kinase 1) activates macroautophagy and mitophagy, respectively, and removes cellular debris accumulated over AMD progression. Ectopic expression of telomerase in retinal pigment epithelium (RPE) cells lengthened telomeres, reduced senescence, and extended their lifespan. These effects provide evidence for the potential of telomerase in AMD therapy. Peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PGC-1α) may be involved in AMD pathogenesis through decreasing oxidative stress and senescence, regulation of vascular endothelial growth factor (VEGF), and improving autophagy. PGC-1α and TERT form an inhibitory positive feedback loop. In conclusion, telomerase activation and its ectopic expression in RPE cells, as well as controlled clinical trials on the effects of telomerase activation in AMD patients, are justified and should be assisted by PGC-1α modulators to increase the therapeutic potential of telomerase in AMD.
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Affiliation(s)
- Janusz Blasiak
- Department of Molecular Genetics, Faculty of Biology and Environmental Protection, University of Lodz, Pomorska 141/143, 90-236 Lodz, Poland
- Correspondence: (J.B.); (K.K.)
| | - Joanna Szczepanska
- Department of Pediatric Dentistry, Medical University of Lodz, 92-216 Lodz, Poland;
| | - Michal Fila
- Department of Developmental Neurology and Epileptology, Polish Mother’s Memorial Hospital Research Institute, 93-338 Lodz, Poland;
| | - Elzbieta Pawlowska
- Department of Orthodontics, Medical University of Lodz, 92-217 Lodz, Poland;
| | - Kai Kaarniranta
- Department of Ophthalmology, University of Eastern Finland, 70210 Kuopio, Finland
- Department of Ophthalmology, Kuopio University Hospital, 70210 Kuopio, Finland
- Correspondence: (J.B.); (K.K.)
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2
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Schrumpfová PP, Fajkus J. Composition and Function of Telomerase-A Polymerase Associated with the Origin of Eukaryotes. Biomolecules 2020; 10:biom10101425. [PMID: 33050064 PMCID: PMC7658794 DOI: 10.3390/biom10101425] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2020] [Revised: 09/29/2020] [Accepted: 10/01/2020] [Indexed: 12/19/2022] Open
Abstract
The canonical DNA polymerases involved in the replication of the genome are unable to fully replicate the physical ends of linear chromosomes, called telomeres. Chromosomal termini thus become shortened in each cell cycle. The maintenance of telomeres requires telomerase—a specific RNA-dependent DNA polymerase enzyme complex that carries its own RNA template and adds telomeric repeats to the ends of chromosomes using a reverse transcription mechanism. Both core subunits of telomerase—its catalytic telomerase reverse transcriptase (TERT) subunit and telomerase RNA (TR) component—were identified in quick succession in Tetrahymena more than 30 years ago. Since then, both telomerase subunits have been described in various organisms including yeasts, mammals, birds, reptiles and fish. Despite the fact that telomerase activity in plants was described 25 years ago and the TERT subunit four years later, a genuine plant TR has only recently been identified by our group. In this review, we focus on the structure, composition and function of telomerases. In addition, we discuss the origin and phylogenetic divergence of this unique RNA-dependent DNA polymerase as a witness of early eukaryotic evolution. Specifically, we discuss the latest information regarding the recently discovered TR component in plants, its conservation and its structural features.
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Affiliation(s)
- Petra Procházková Schrumpfová
- Laboratory of Functional Genomics and Proteomics, National Centre for Biomolecular Research, Faculty of Science, Masaryk University, Kotlářská 2, CZ-61137 Brno, Czech Republic;
- Mendel Centre for Plant Genomics and Proteomics, Central European Institute of Technology, Masaryk University, Kamenice 5, CZ-62500 Brno, Czech Republic
- Correspondence:
| | - Jiří Fajkus
- Laboratory of Functional Genomics and Proteomics, National Centre for Biomolecular Research, Faculty of Science, Masaryk University, Kotlářská 2, CZ-61137 Brno, Czech Republic;
- Mendel Centre for Plant Genomics and Proteomics, Central European Institute of Technology, Masaryk University, Kamenice 5, CZ-62500 Brno, Czech Republic
- The Czech Academy of Sciences, Institute of Biophysics, Královopolská 135, 612 65 Brno, Czech Republic
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Fouillade C, Curras-Alonso S, Giuranno L, Quelennec E, Heinrich S, Bonnet-Boissinot S, Beddok A, Leboucher S, Karakurt HU, Bohec M, Baulande S, Vooijs M, Verrelle P, Dutreix M, Londoño-Vallejo A, Favaudon V. FLASH Irradiation Spares Lung Progenitor Cells and Limits the Incidence of Radio-induced Senescence. Clin Cancer Res 2020; 26:1497-1506. [PMID: 31796518 DOI: 10.1158/1078-0432.ccr-19-1440] [Citation(s) in RCA: 128] [Impact Index Per Article: 32.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2019] [Revised: 08/29/2019] [Accepted: 11/27/2019] [Indexed: 11/16/2022]
Abstract
PURPOSE One of the main limitations to anticancer radiotherapy lies in irreversible damage to healthy tissues located within the radiation field. "FLASH" irradiation at very high dose-rate is a new treatment modality that has been reported to specifically spare normal tissue from late radiation-induced toxicity in animal models and therefore could be a promising strategy to reduce treatment toxicity. EXPERIMENTAL DESIGN Lung responses to FLASH irradiation were investigated by qPCR, single-cell RNA sequencing (sc-RNA-Seq), and histologic methods during the acute wound healing phase as well as at late stages using C57BL/6J wild-type and Terc-/- mice exposed to bilateral thorax irradiation as well as human lung cells grown in vitro. RESULTS In vitro studies gave evidence of a reduced level of DNA damage and induced lethality at the advantage of FLASH. In mouse lung, sc-RNA-seq and the monitoring of proliferating cells revealed that FLASH minimized the induction of proinflammatory genes and reduced the proliferation of progenitor cells after injury. At late stages, FLASH-irradiated lungs presented less persistent DNA damage and senescent cells than after CONV exposure, suggesting a higher potential for lung regeneration with FLASH. Consistent with this hypothesis, the beneficial effect of FLASH was lost in Terc-/- mice harboring critically short telomeres and lack of telomerase activity. CONCLUSIONS The results suggest that, compared with conventional radiotherapy, FLASH minimizes DNA damage in normal cells, spares lung progenitor cells from excessive damage, and reduces the risk of replicative senescence.
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Affiliation(s)
- Charles Fouillade
- Institut Curie, Inserm U 1021-CNRS UMR 3347, University Paris-Saclay, PSL Research University, Centre Universitaire, Orsay, France.
| | - Sandra Curras-Alonso
- Institut Curie, Inserm U 1021-CNRS UMR 3347, University Paris-Saclay, PSL Research University, Centre Universitaire, Orsay, France
- Institut Curie, CNRS UMR 3244, PSL Research University, Paris, France
| | - Lorena Giuranno
- Department of Radiotherapy, Grow-School for Oncology and Developmental Biology, Maastricht University, Maastricht, the Netherlands
| | - Eddy Quelennec
- Institut Curie, Inserm U 1021-CNRS UMR 3347, University Paris-Saclay, PSL Research University, Centre Universitaire, Orsay, France
| | - Sophie Heinrich
- Institut Curie, Inserm U 1021-CNRS UMR 3347, University Paris-Saclay, PSL Research University, Centre Universitaire, Orsay, France
- Institut Curie, Translational Research Department, Experimental Radiotherapy Platform, PSL Research University, Centre Universitaire, Orsay, France
| | - Sarah Bonnet-Boissinot
- Institut Curie, Inserm U 1021-CNRS UMR 3347, University Paris-Saclay, PSL Research University, Centre Universitaire, Orsay, France
| | - Arnaud Beddok
- Institut Curie, Inserm U 1021-CNRS UMR 3347, University Paris-Saclay, PSL Research University, Centre Universitaire, Orsay, France
| | - Sophie Leboucher
- Institut Curie, CNRS UMR 3348, University Paris-Saclay, PSL Research University, Centre Universitaire, Orsay, France
| | | | - Mylène Bohec
- Institut Curie Genomics of Excellence (ICGex) Platform, Paris, France
| | - Sylvain Baulande
- Institut Curie Genomics of Excellence (ICGex) Platform, Paris, France
| | - Marc Vooijs
- Department of Radiotherapy, Grow-School for Oncology and Developmental Biology, Maastricht University, Maastricht, the Netherlands
| | - Pierre Verrelle
- Radiation Oncology Department, Institut Curie, Paris, France
- Institut Curie, Inserm U 1196-CNRS UMR 9187, University Paris-Saclay, PSL Research University, Centre Universitaire, Orsay, France
| | - Marie Dutreix
- Institut Curie, Inserm U 1021-CNRS UMR 3347, University Paris-Saclay, PSL Research University, Centre Universitaire, Orsay, France
| | | | - Vincent Favaudon
- Institut Curie, Inserm U 1021-CNRS UMR 3347, University Paris-Saclay, PSL Research University, Centre Universitaire, Orsay, France.
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Minafra M, Laforgia R, Sederino MG, Fedele S, Delvecchio A, Lattarulo S, Carbotta G, Fabiano G. Study of the role of telomerase in colorectal cancer: preliminary report and literature review. G Chir 2019; 38:213-218. [PMID: 29280699 DOI: 10.11138/gchir/2017.38.5.213] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
AIM The aim of our study is to focus on hTERT (human Telomerase Reverse Transcriptase) expression to identify tumoral tissue after a comparison to TP53 and KRAS. More than 85% of cancer cells contain genetic aberrations and also overexpression of hTERT, and, in fact, the promoter of hTERT characterizes all malignant cells. PATIENTS AND METHODS Our sample is composed of 18 patients, including 10 with CRC that underwent surgical procedure and 8 patients without CRC, which represent the control group. The hTERT gene expression, KRAS and p53 were evaluated by methodical Real Time - PCR on RNA extracted from tumor tissues, peritumoral tissue and control cases. RESULTS Within the CRC group the evaluation of the tumor tissue showed an increase of hTERT expression with a statistical significance (> 0.1) in 5 of these, also associated with substantial increase of KRAS (> 0.2). The peritumoral tissue assessment showed important increase in KRAS in 4 patients (> 0.2), while hTERT is not found to be particularly increased. The value of p53 did not show any particular significance (<0.1). DISCUSSION The analysis of our data leads us to consider that the increase of hTERT is evident in patients suffering from CRC and that some of them will become significant in relation to the increase of KRAS and independent of p53. In peritumoral tissues, however, KRAS increases considerably, instead hTERT maintains a low concentration and this is compatible with the cellular evolution of the neoplastic tissue adjacent to the tumor. CONCLUSIONS hTERT could be used for diagnosis and prognosis in the future, to be able to identify the risk of tumor progression and to set up an adequate therapy.
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Hernandez-Sanchez W, Huang W, Plucinsky B, Garcia-Vazquez N, Robinson NJ, Schiemann WP, Berdis AJ, Skordalakes E, Taylor DJ. A non-natural nucleotide uses a specific pocket to selectively inhibit telomerase activity. PLoS Biol 2019; 17:e3000204. [PMID: 30951520 PMCID: PMC6469803 DOI: 10.1371/journal.pbio.3000204] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2018] [Revised: 04/17/2019] [Accepted: 03/14/2019] [Indexed: 12/13/2022] Open
Abstract
Telomerase, a unique reverse transcriptase that specifically extends the ends of linear chromosomes, is up-regulated in the vast majority of cancer cells. Here, we show that an indole nucleotide analog, 5-methylcarboxyl-indolyl-2'-deoxyriboside 5'-triphosphate (5-MeCITP), functions as an inhibitor of telomerase activity. The crystal structure of 5-MeCITP bound to the Tribolium castaneum telomerase reverse transcriptase reveals an atypical interaction, in which the nucleobase is flipped in the active site. In this orientation, the methoxy group of 5-MeCITP extends out of the canonical active site to interact with a telomerase-specific hydrophobic pocket formed by motifs 1 and 2 in the fingers domain and T-motif in the RNA-binding domain of the telomerase reverse transcriptase. In vitro data show that 5-MeCITP inhibits telomerase with a similar potency as the clinically administered nucleoside analog reverse transcriptase inhibitor azidothymidine (AZT). In addition, cell-based studies show that treatment with the cell-permeable nucleoside counterpart of 5-MeCITP leads to telomere shortening in telomerase-positive cancer cells, while resulting in significantly lower cytotoxic effects in telomerase-negative cell lines when compared with AZT treatment.
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Affiliation(s)
| | - Wei Huang
- Department of Pharmacology, Case Western Reserve University, Cleveland, Ohio, United States of America
| | - Brian Plucinsky
- The Wistar Institute Gene Expression and Regulation Program, Philadelphia, Pennsylvania, United States of America
| | - Nelson Garcia-Vazquez
- Department of Pharmacology, Case Western Reserve University, Cleveland, Ohio, United States of America
| | - Nathaniel J. Robinson
- Department of Pathology, Case Western Reserve University, Cleveland, Ohio, United States of America
| | - William P. Schiemann
- Case Comprehensive Cancer Center, Case Western Reserve University, Cleveland, Ohio, United States of America
| | - Anthony J. Berdis
- Department of Chemistry, Cleveland State University, Cleveland, Ohio, United States of America
| | - Emmanuel Skordalakes
- The Wistar Institute Gene Expression and Regulation Program, Philadelphia, Pennsylvania, United States of America
| | - Derek J. Taylor
- Department of Pharmacology, Case Western Reserve University, Cleveland, Ohio, United States of America
- Department of Biochemistry, Case Western Reserve University, Cleveland, Ohio, United States of America
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Cheung DST, Deng W, Tsao SW, Ho RTH, Chan CLW, Fong DYT, Chau PH, Hong AWL, Fung HYKY, Ma JLC, Tiwari AFY. Effect of a Qigong Intervention on Telomerase Activity and Mental Health in Chinese Women Survivors of Intimate Partner Violence: A Randomized Clinical Trial. JAMA Netw Open 2019; 2:e186967. [PMID: 30646209 PMCID: PMC6484539 DOI: 10.1001/jamanetworkopen.2018.6967] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
IMPORTANCE Qigong is a mind-body exercise that may be an effective self-care intervention for improving the well-being of women survivors of intimate partner violence. OBJECTIVE To test whether a qigong intervention would increase telomerase activity and improve mental health in Chinese women who survived intimate partner violence. DESIGN, SETTING, AND PARTICIPANTS A single-blind randomized clinical trial among Chinese women (N = 271) who survived intimate partner violence in the past 2 years recruited from a community center in Hong Kong, China. The trial was conducted from March 12, 2014, to May 26, 2016. Data analysis was by intention to treat and performed from June 7 to August 24, 2018. INTERVENTIONS Randomization (1:1) to a 22-week qigong intervention (n = 136) that included 22 weeks of Baduanjin qigong group training (1-6 weeks: 2-hour sessions biweekly; 7-22 weeks: 1-hour follow-up sessions weekly) and self-practice (30 minutes per day for 22 weeks) or to a wait-list control group (n = 135) that received optional monthly health education sessions unrelated to qigong after 6 weeks (posttraining period) and qigong training after 22 weeks (postintervention period). MAIN OUTCOMES AND MEASURES The primary outcome was telomerase activity in peripheral blood mononuclear cells. The secondary outcomes included levels of proinflammatory cytokines (tumor necrosis factor and interleukin 6) in peripheral blood plasma, depressive symptoms (Beck Depression Inventory II score; score range, 0-63; higher scores represent more severe depressive symptoms), perceived stress (Perceived Stress Scale; score range, 0-40; higher scores represent higher stress), and perceived coping (Perceived Coping Scale; score range, 0-13; higher scores represent use of more coping strategies). RESULTS From 1611 Chinese women screened (mean [SD] age, 42.0 [8.8] years), 247 of 271 randomized participants completed the study (intervention group, 120; wait-list control group, 127). Telomerase activity of the intervention group participants after 22 weeks was not significantly different from that of the wait-list control group participants (5.18 U [95% CI, 5.05-5.31 U] in the intervention group vs 5.14 U [95% CI, 5.01-5.27 U] in the wait-list control group; P = .66). The mean change in telomerase activity from baseline was marginally significant in the intervention group (effect size [d], 0.13; 95% CI, 0.001-0.27) but not in the wait-list control group (d, -0.03; 95% CI, -0.16 to 0.10). Perceived stress and depressive symptoms were significantly lower in the intervention group than in the wait-list control group after 6 weeks (between-group differences: perceived stress: d, -1.81; 95% CI, -3.27 to -0.34; depressive symptoms: d, -3.57; 95% CI, -6.25 to -0.90), but not after 22 weeks (between-group differences: perceived stress: d, -1.03; 95% CI, -2.50 to 0.43; depressive symptoms: d, -1.78; 95% CI, -4.26 to 0.70). CONCLUSIONS AND RELEVANCE The findings of this study do not support a significant benefit of Baduanjin qigong on telomerase activity in women who have survived intimate partner violence. However, outcomes related to mental health seem to be improved, which should be confirmed by additional studies. TRIAL REGISTRATION ClinicalTrials.gov Identifier: NCT02060123.
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Affiliation(s)
- Denise Shuk Ting Cheung
- School of Nursing, Li Ka Shing Faculty of Medicine, University of Hong Kong, Hong Kong, China
| | - Wen Deng
- School of Nursing, Li Ka Shing Faculty of Medicine, University of Hong Kong, Hong Kong, China
| | - Sai-Wah Tsao
- School of Biomedical Sciences, Li Ka Shing Faculty of Medicine, University of Hong Kong, Hong Kong, China
| | - Rainbow Tin Hung Ho
- Centre on Behavioral Health, The University of Hong Kong, Hong Kong, China
- Department of Social Work and Social Administration, University of Hong Kong, Pokfulam, Hong Kong, China
| | - Cecilia Lai Wan Chan
- Department of Social Work and Social Administration, University of Hong Kong, Pokfulam, Hong Kong, China
| | - Daniel Yee Tak Fong
- School of Nursing, Li Ka Shing Faculty of Medicine, University of Hong Kong, Hong Kong, China
| | - Pui Hing Chau
- School of Nursing, Li Ka Shing Faculty of Medicine, University of Hong Kong, Hong Kong, China
| | - Athena Wai Lin Hong
- School of Nursing, Li Ka Shing Faculty of Medicine, University of Hong Kong, Hong Kong, China
| | | | - Joyce Lai Chong Ma
- Department of Social Work, Chinese University of Hong Kong, United College, Shatin, New Territories, Hong Kong, China
| | - Agnes F. Y. Tiwari
- School of Nursing, Hong Kong Sanatorium and Hospital, Wong Chuk Hang, Hong Kong, China
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Werner CM, Hecksteden A, Morsch A, Zundler J, Wegmann M, Kratzsch J, Thiery J, Hohl M, Bittenbring JT, Neumann F, Böhm M, Meyer T, Laufs U. Differential effects of endurance, interval, and resistance training on telomerase activity and telomere length in a randomized, controlled study. Eur Heart J 2019; 40:34-46. [PMID: 30496493 PMCID: PMC6312574 DOI: 10.1093/eurheartj/ehy585] [Citation(s) in RCA: 98] [Impact Index Per Article: 19.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/11/2017] [Revised: 02/26/2018] [Accepted: 09/21/2018] [Indexed: 02/07/2023] Open
Abstract
Aims It is unknown whether different training modalities exert differential cellular effects. Telomeres and telomere-associated proteins play a major role in cellular aging with implications for global health. This prospective training study examines the effects of endurance training, interval training (IT), and resistance training (RT) on telomerase activity and telomere length (TL). Methods and results One hundred and twenty-four healthy previously inactive individuals completed the 6 months study. Participants were randomized to three different interventions or the control condition (no change in lifestyle): aerobic endurance training (AET, continuous running), high-intensive IT (4 × 4 method), or RT (circle training on 8 devices), each intervention consisting of three 45 min training sessions per week. Maximum oxygen uptake (VO2max) was increased by all three training modalities. Telomerase activity in blood mononuclear cells was up-regulated by two- to three-fold in both endurance exercise groups (AET, IT), but not with RT. In parallel, lymphocyte, granulocyte, and leucocyte TL increased in the endurance-trained groups but not in the RT group. Magnet-activated cell sorting with telomerase repeat-ampliflication protocol (MACS-TRAP) assays revealed that a single bout of endurance training-but not RT-acutely increased telomerase activity in CD14+ and in CD34+ leucocytes. Conclusion This randomized controlled trial shows that endurance training, IT, and RT protocols induce specific cellular pathways in circulating leucocytes. Endurance training and IT, but not RT, increased telomerase activity and TL which are important for cellular senescence, regenerative capacity, and thus, healthy aging.
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Affiliation(s)
- Christian M Werner
- Klinik für Innere Medizin III, Kardiologie, Angiologie und Internistische Intensivmedizin, Universität und Universitätsklinikum des Saarlandes, Geb. 41.1/IMED, Homburg/Saar, Germany
| | - Anne Hecksteden
- Institut für Sport und Präventivmedizin, Universität des Saarlandes, Campus, B8 2, Saarbrücken, Germany
| | - Arne Morsch
- Deutsche Hochschule für Prävention und Gesundheitsmanagement, Hermann-Neuberger-Sportschule 3, Saarbrücken, Germany
| | - Joachim Zundler
- Klinik für Innere Medizin III, Kardiologie, Angiologie und Internistische Intensivmedizin, Universität und Universitätsklinikum des Saarlandes, Geb. 41.1/IMED, Homburg/Saar, Germany
| | - Melissa Wegmann
- Institut für Sport und Präventivmedizin, Universität des Saarlandes, Campus, B8 2, Saarbrücken, Germany
| | - Jürgen Kratzsch
- Institut für Labormedizin, Klinische Chemie und Molekulare Diagnostik, Universitätsklinikum, Liebigstr. 20, Leipzig, Germany
| | - Joachim Thiery
- Institut für Labormedizin, Klinische Chemie und Molekulare Diagnostik, Universitätsklinikum, Liebigstr. 20, Leipzig, Germany
| | - Mathias Hohl
- Klinik für Innere Medizin III, Kardiologie, Angiologie und Internistische Intensivmedizin, Universität und Universitätsklinikum des Saarlandes, Geb. 41.1/IMED, Homburg/Saar, Germany
| | - Jörg Thomas Bittenbring
- Klinik für Innere Medizin I, Onkologie, Hämatologie, Klinische Immunologie und Rheumatologie, Universitätsklinikum des Saarlandes, Geb. 41.1/IMED, Homburg/Saar, Germany
| | - Frank Neumann
- Klinik für Innere Medizin I, Onkologie, Hämatologie, Klinische Immunologie und Rheumatologie, Universitätsklinikum des Saarlandes, Geb. 41.1/IMED, Homburg/Saar, Germany
| | - Michael Böhm
- Klinik für Innere Medizin III, Kardiologie, Angiologie und Internistische Intensivmedizin, Universität und Universitätsklinikum des Saarlandes, Geb. 41.1/IMED, Homburg/Saar, Germany
| | - Tim Meyer
- Institut für Sport und Präventivmedizin, Universität des Saarlandes, Campus, B8 2, Saarbrücken, Germany
| | - Ulrich Laufs
- Klinik und Poliklinik für Kardiologie, Universitätsklinikum Leipzig, Liebigstr. 20, Leipzig, Germany
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Rhee J, Park K, Kim KC, Shin CY, Chung C. Impaired Hippocampal Synaptic Plasticity and Enhanced Excitatory Transmission in a Novel Animal Model of Autism Spectrum Disorders with Telomerase Reverse Transcriptase Overexpression. Mol Cells 2018; 41:486-494. [PMID: 29696935 PMCID: PMC5974625 DOI: 10.14348/molcells.2018.0145] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2018] [Accepted: 04/02/2018] [Indexed: 01/23/2023] Open
Abstract
Recently, we have reported that animals with telomerase reverse transcriptase (TERT) overexpression exhibit reduced social interaction, decreased preference for novel social interaction and poor nest-building behaviors symptoms that mirror those observed in human autism spectrum disorders (ASD). Overexpression of TERT also alters the excitatory/inhibitory (E/I) ratio in the medial prefrontal cortex. However, the effects of TERT overexpression on hippocampal-dependent learning and synaptic efficacy have not been investigated. In the present study, we employed electrophysiological approaches in combination with behavioral analysis to examine hippocampal function of TERT transgenic (TERT-tg) mice and FVB controls. We found that TERT overexpression results in enhanced hippocampal excitation with no changes in inhibition and significantly impairs long-term synaptic plasticity. Interestingly, the expression levels of phosphorylated CREB and phosphory-lated CaMKIIα were significantly decreased while the expression level of CaMKIIα was slightly increased in the hippocampus of TERT-overexpressing mice. Our observations highlight the importance of TERT in normal synaptic function and behavior and provide additional information on a novel animal model of ASD associated with TERT overexpression.
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Affiliation(s)
- Jeehae Rhee
- Department of Biological Sciences, College of Bioscience and Biotechnology, Konkuk University, Seoul 05029,
Korea
| | - Kwanghoon Park
- Department of Biological Sciences, College of Bioscience and Biotechnology, Konkuk University, Seoul 05029,
Korea
| | - Ki Chan Kim
- Department of Neuroscience and Department of Advanced Translational Medicine, School of Medicine, Konkuk University, Seoul 05029,
Korea
| | - Chan Young Shin
- Department of Neuroscience and Department of Advanced Translational Medicine, School of Medicine, Konkuk University, Seoul 05029,
Korea
| | - ChiHye Chung
- Department of Biological Sciences, College of Bioscience and Biotechnology, Konkuk University, Seoul 05029,
Korea
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Meng JJ, Li SP, Zhao FY, Tong Y, Mu DZ, Qu Y. [Effect of telomerase activation on biological behaviors of neural stem cells in rats with hypoxic-ischemic insults]. Zhongguo Dang Dai Er Ke Za Zhi 2017; 19:229-236. [PMID: 28202125 PMCID: PMC7389468] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Received: 08/25/2016] [Accepted: 12/08/2016] [Indexed: 11/12/2023]
Abstract
OBJECTIVE To investigate the effect of telomerase activation on biological behaviors of neural stem cells after hypoxic-ischemic insults. METHODS The neural stem cells passaged in vitro were divided into four groups: control, oxygen-glucose deprivation (OGD), OGD+cycloastragenol (CAG) high concentration (final concentration of 25 μM), and OGD+CAG low concentration (final concentration of 10 μM). The latter three groups were subjected to OGD. Telomerase reverse transcriptase (TERT) expression level was evaluated by Western blot. Telomerase activity was detected by telomerase repeat amplification protocol (TRAP). Cell number and neural sphere diameter were measured under a microscope. The activity of lactate dehydrogenase (LDH) was examined by chemiluminescence. Cell proliferation rate and apoptosis were detected by flow cytometry. RESULTS After OGD insults, obvious injury of neural stem cells was observed, including less cell number, smaller neural sphere, more dead cells, lower proliferation rate and decreased survival rate. In CAG-treated groups, there were higher TERT expression level and telomerase activity compared with the control group (P<0.05). In comparison with the OGD group, CAG treatment attenuated cell loss (P<0.05) and neural sphere diameter decrease (P<0.05), promoted cell proliferation (P<0.05), and increased cell survival rate (P<0.05). Low and high concentrations of CAG had similar effects on proliferation and survival of neural stem cells (P>0.05). In the normal cultural condition, CAG treatment also enhanced TERT expression (P<0.05) and increased cell numbers (P<0.05) and neural sphere diameter (P<0.05) compared with the control group. CONCLUSIONS Telomerase activation can promote the proliferation and improve survival of neural stem cells under the state of hypoxic-ischemic insults, suggesting telomerase activators might be potential agents for the therapy of hypoxic-ischemic brain injury.
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Affiliation(s)
- Jun-Jie Meng
- Department of Pediatrics, West China Second University Hospital, Sichuan University/Key Laboratory of Birth Defects and Related Diseases of Women and Children, Ministry of Education/Key Laboratory of Development and Related Diseases of Women and Children, Chengdu 610041, China.
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10
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Meng JJ, Li SP, Zhao FY, Tong Y, Mu DZ, Qu Y. [Effect of telomerase activation on biological behaviors of neural stem cells in rats with hypoxic-ischemic insults]. Zhongguo Dang Dai Er Ke Za Zhi 2017; 19:229-236. [PMID: 28202125 PMCID: PMC7389468 DOI: 10.7499/j.issn.1008-8830.2017.02.019] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Received: 08/25/2016] [Accepted: 12/08/2016] [Indexed: 06/06/2023]
Abstract
OBJECTIVE To investigate the effect of telomerase activation on biological behaviors of neural stem cells after hypoxic-ischemic insults. METHODS The neural stem cells passaged in vitro were divided into four groups: control, oxygen-glucose deprivation (OGD), OGD+cycloastragenol (CAG) high concentration (final concentration of 25 μM), and OGD+CAG low concentration (final concentration of 10 μM). The latter three groups were subjected to OGD. Telomerase reverse transcriptase (TERT) expression level was evaluated by Western blot. Telomerase activity was detected by telomerase repeat amplification protocol (TRAP). Cell number and neural sphere diameter were measured under a microscope. The activity of lactate dehydrogenase (LDH) was examined by chemiluminescence. Cell proliferation rate and apoptosis were detected by flow cytometry. RESULTS After OGD insults, obvious injury of neural stem cells was observed, including less cell number, smaller neural sphere, more dead cells, lower proliferation rate and decreased survival rate. In CAG-treated groups, there were higher TERT expression level and telomerase activity compared with the control group (P<0.05). In comparison with the OGD group, CAG treatment attenuated cell loss (P<0.05) and neural sphere diameter decrease (P<0.05), promoted cell proliferation (P<0.05), and increased cell survival rate (P<0.05). Low and high concentrations of CAG had similar effects on proliferation and survival of neural stem cells (P>0.05). In the normal cultural condition, CAG treatment also enhanced TERT expression (P<0.05) and increased cell numbers (P<0.05) and neural sphere diameter (P<0.05) compared with the control group. CONCLUSIONS Telomerase activation can promote the proliferation and improve survival of neural stem cells under the state of hypoxic-ischemic insults, suggesting telomerase activators might be potential agents for the therapy of hypoxic-ischemic brain injury.
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Affiliation(s)
- Jun-Jie Meng
- Department of Pediatrics, West China Second University Hospital, Sichuan University/Key Laboratory of Birth Defects and Related Diseases of Women and Children, Ministry of Education/Key Laboratory of Development and Related Diseases of Women and Children, Chengdu 610041, China.
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11
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Pavlov KI, Mukhin VN, Klimenko VM, Anisimov VN. [Telomere-telomerase system in aging, norm and pathology (literature review)]. Adv Gerontol 2017; 30:17-26. [PMID: 28557385] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
This literature review presents results of research showing association between functional activity of the telomere-telomerase system and mental cognitive and emotional processes in normal and various pathological states: chronic stress, depression, bipolar disorder, schizophrenia, mild cognitive impairment and dementia in aging. It also refers to age-specific, psycho-social, economic, immunological, genetic and epigenetic factors that influence these relationships.
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Affiliation(s)
- K I Pavlov
- Institute of Experimental Medicine, Saint-Petersburg, 197376, Russian Federation;
| | - V N Mukhin
- Institute of Experimental Medicine, Saint-Petersburg, 197376, Russian Federation;
| | - V M Klimenko
- Institute of Experimental Medicine, Saint-Petersburg, 197376, Russian Federation;
| | - V N Anisimov
- N.N.Petrov Research Institute of Oncology, Pesochny, Saint-Petersburg, 197758, Russian Federation
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12
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Xu Y, Wang X, Chen SM, Chen C, Wang Y, Xiao BK, Tao ZZ. Effect of silencing key proteins in telomerase mechanism and alternative lengthening of telomeres mechanism in laryngeal cancer cells. Am J Otolaryngol 2016; 37:552-558. [PMID: 27726944 DOI: 10.1016/j.amjoto.2016.07.009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2016] [Accepted: 07/18/2016] [Indexed: 11/29/2022]
Abstract
PURPOSE To explore the influences of telomerase and alternative lengthening of telomeres mechanism on telomere length and laryngeal squamous cell carcinoma in vitro and in vivo. MATERIALS AND METHODS Short hairpin RNA expression vectors targeting the messenger TERT, TRF2, RAD51 and NBS1 were constructed. The mRNA and protein expression of targeted genes in human laryngeal squamous carcinoma cell line HEp-2 was evaluated by reverse transcription polymerase chain reaction and Western blotting separately. The length of telomere was analyzed by fluorescent in-situ hybridization. Cell viability was examined by cell counting Kit-8. Effects on tumor growth were also investigated in vivo. RESULTS The transfection of multiple short hairpin RNAs expression plasmid significantly inhibited the mRNA and protein expression of related genes. Silence of alternative lengthening of telomeres mechanism and telomerase mechanism related genes resulted in the shortening of telomere length in HEp-2 cell. However, silence of alternative lengthening of telomeres mechanism related genes could shorten the telomere length but had no significant difference. Both simultaneously and separately blocking telomerase mechanism and alternative lengthening of telomeres mechanism resulted in reduction of tumor cell viability. Silence of alternative lengthening of telomeres mechanism and telomerase mechanism related genes inhibited the tumor growth in vivo. CONCLUSIONS The inhibition of telomere related gene may be a promising strategy for the treatment of laryngeal squamous cell carcinoma.
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Affiliation(s)
- Yong Xu
- Department of Otolaryngology - Head and Neck Surgery, Renmin Hospital of Wuhan University, Wuhan, China
| | - Xiao Wang
- Department of Ultrasonography, Zhongnan Hospital of Wuhan University, Wuhan, China
| | - Shi-Ming Chen
- Department of Otolaryngology - Head and Neck Surgery, Renmin Hospital of Wuhan University, Wuhan, China
| | - Chen Chen
- Department of Otolaryngology - Head and Neck Surgery, Renmin Hospital of Wuhan University, Wuhan, China
| | - Yan Wang
- Department of Otolaryngology - Head and Neck Surgery, Renmin Hospital of Wuhan University, Wuhan, China
| | - Bo-Kui Xiao
- Department of Otolaryngology - Head and Neck Surgery, Renmin Hospital of Wuhan University, Wuhan, China
| | - Ze-Zhang Tao
- Department of Otolaryngology - Head and Neck Surgery, Renmin Hospital of Wuhan University, Wuhan, China.
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13
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Khattar E, Kumar P, Liu CY, Akıncılar SC, Raju A, Lakshmanan M, Maury JJP, Qiang Y, Li S, Tan EY, Hui KM, Shi M, Loh YH, Tergaonkar V. Telomerase reverse transcriptase promotes cancer cell proliferation by augmenting tRNA expression. J Clin Invest 2016; 126:4045-4060. [PMID: 27643433 DOI: 10.1172/jci86042] [Citation(s) in RCA: 92] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2015] [Accepted: 08/11/2016] [Indexed: 12/13/2022] Open
Abstract
Transcriptional reactivation of telomerase reverse transcriptase (TERT) reconstitutes telomerase activity in the majority of human cancers. Here, we found that ectopic TERT expression increases cell proliferation, while acute reductions in TERT levels lead to a dramatic loss of proliferation without any change in telomere length, suggesting that the effects of TERT could be telomere independent. We observed that TERT determines the growth rate of cancer cells by directly regulating global protein synthesis independently of its catalytic activity. Genome-wide TERT binding across 5 cancer cell lines and 2 embryonic stem cell lines revealed that endogenous TERT, driven by mutant promoters or oncogenes, directly associates with the RNA polymerase III (pol III) subunit RPC32 and enhances its recruitment to chromatin, resulting in increased RNA pol III occupancy and tRNA expression in cancers. TERT-deficient mice displayed marked delays in polyomavirus middle T oncogene-induced (PyMT-induced) mammary tumorigenesis, increased survival, and reductions in tRNA levels. Ectopic expression of either RPC32 or TERT restored tRNA levels and proliferation defects in TERT-depleted cells. Finally, we determined that levels of TERT and tRNA correlated in breast and liver cancer samples. Together, these data suggest the existence of a unifying mechanism by which TERT enhances translation in cells to regulate cancer cell proliferation.
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MESH Headings
- Animals
- Cell Line, Tumor
- Cell Proliferation
- Cell Transformation, Neoplastic/metabolism
- Female
- Gene Expression Regulation, Neoplastic
- HEK293 Cells
- Humans
- Mammary Neoplasms, Experimental/enzymology
- Mammary Neoplasms, Experimental/pathology
- Mice, 129 Strain
- Mice, Inbred C57BL
- Mice, Inbred NOD
- Mice, Knockout
- Mice, SCID
- Neoplasm Transplantation
- Promoter Regions, Genetic
- Protein Binding
- Protein Biosynthesis
- Protein Interaction Domains and Motifs
- RNA Polymerase III/metabolism
- RNA, Transfer/genetics
- RNA, Transfer/metabolism
- Telomerase/physiology
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14
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Abstract
It has been proposed that miRNAs are involved in the control of telomeres. We test that hypothesis by examining the association between miRNAs and telomere length (TL). Additionally, we evaluate if genetic variation in telomerase reverse transcriptase (TERT) is associated with miRNA expression levels. We use data from a population-based study of colorectal cancer (CRC), where we have previously shown associations between TL and TERT and CRC, to test associations between TL and miRNA expression and TERT and miRNA expression. To gain insight into functions of miRNAs associated with TERT we tested linear associations between miRNAs and their targeted gene mRNAs. An Agilent platform that contained information on over 2000 miRNAs was used. TL was measured using a multiplexed quantitative PCR (qPCR). RNAseq was used to assess gene expression. Our sample consisted of 1152 individuals with SNP data and miRNA expression data; 363 individuals with both TL and miRNA; and 148 individuals with miRNA and mRNA data. Thirty-three miRNAs were directly associated with TL after adjusting for age and sex (false discovery rate (FDR) of 0.05). TERT rs2736118 was associated with differences in miRNA expression between carcinoma and normal colonic mucosa for 75 miRNAs (FDR <0.05). Genes regulated by these miRNAs, as indicated by mRNA/miRNA associations, were associated with major signaling pathways beyond their TL-related functions, including PTEN, and PI3K/AKT signaling. Our data support a direct association between miRNAs and TL; differences in miRNA expression levels by TERT genotype were observed. Based on miRNA and targeted mRNA associations our data suggest that TERT is involved in non-TL-related functions by acting through altered miRNA expression.
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Affiliation(s)
- Martha L. Slattery
- Department of Medicine, University of Utah, 383 Colorow, Salt Lake City, Utah 84108, United States of America
- * E-mail:
| | - Jennifer S. Herrick
- Department of Medicine, University of Utah, 383 Colorow, Salt Lake City, Utah 84108, United States of America
| | - Andrew J. Pellatt
- Department of Medicine, University of Utah, 383 Colorow, Salt Lake City, Utah 84108, United States of America
| | - Roger K. Wolff
- Department of Medicine, University of Utah, 383 Colorow, Salt Lake City, Utah 84108, United States of America
| | - Lila E. Mullany
- Department of Medicine, University of Utah, 383 Colorow, Salt Lake City, Utah 84108, United States of America
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15
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Alvero AB, Fishman DA, Qumsiyeh MB, Garg M, Kacinski BM, Sapi E. Telomerase Prolongs the Lifespan of Normal Human Ovarian Surface Epithelial Cells Without Inducing Neoplastic Phenotype. ACTA ACUST UNITED AC 2016; 11:553-61. [PMID: 15582501 DOI: 10.1016/j.jsgi.2004.06.006] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
OBJECTIVE The aim of this study was to determine the effects of exogenous expression of the catalytic subunit of telomerase (hTERT) on the lifespan, growth characteristics, and tumorigenicity of normal human ovarian surface epithelial (OSE) cells. METHODS Low-passage primary cultures of normal human OSE cells were transfected with hTERT and the resulting cell lines were characterized. RESULTS The ectopic expression of hTERT stabilized the telomeres of the OSE cultures above 8 kb. The hTERT-transfected OSE cell lines grew beyond the normal lifespan seen in OSE cells and propagated in culture for more than 40 passages before senescing. Moreover, the hTERT-transfected cells demonstrated extensive proliferative capacity as evidenced by their ability to continuously grow even when seeded at low dilutions. The morphologic features and normal differentiation patterns seen in normal OSE cells were likewise retained by the hTERT-transfected cells. In addition, the cultures remained responsive to physiologic concentrations of epidermal growth factor and transforming growth factor-beta. Changes associated with neoplastic transformation like anchorage-independent growth, tumorigencity and karyotypic instability were not observed. CONCLUSIONS We were able to show that the ectopic expression of hTERT in normal human OSE: 1) resulted in cultures with greater growth potential and longer lifespan and 2) did not induce a transformed phenotype previously seen in viral oncogene-transfected OSE cells. The established cell lines would not only provide sufficient material for comprehensive studies to investigate the normal physiology of OSE cells, but could also help in the understanding of the early steps of ovarian carcinogenesis.
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Affiliation(s)
- Ayesha B Alvero
- Department of Obstetrics and Gynecology, Yale University School of Medicine, New Haven, Connecticut 06520, USA.
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16
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Rossi MJ, Sundararaj K, Koybasi S, Phillips MS, Szulc ZM, Bielawska A, Day TA, Obeid LM, Hannun YA, Ogretmen B. Inhibition of growth and telomerase activity by novel cationic ceramide analogs with high solubility in human head and neck squamous cell carcinoma cells. Otolaryngol Head Neck Surg 2016; 132:55-62. [PMID: 15632910 DOI: 10.1016/j.otohns.2004.08.015] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
OBJECTIVES: Head and neck squamous cell carcinoma (HNSCC) is notoriously resistant to chemotherapy. The sphingolipid ceramide and its analogs have been demonstrated to exert antitumor activity in many cell types; however, the effectiveness of these analogs has been limited by potency and solubility. This study focuses on the effects of novel highly soluble cationic pyridinium-ceramides, alone and in combination with various chemotherapeutic agents, on cell survival, telomerase activity, and cell cycle arrest in HNSCC cell lines in vitro. METHODS: The concentration of pyridinium-ceramides and chemotherapeutic agents that inhibited cell growth by 50% (IC50) was determined by MTT cell survival assays. The cell cycle profiles were determined by flow cytometry. Telomerase activity was determined by telomerase repeat amplification protocol (TRAP) assay. RESULTS: Treatment of the human UM-SCC-22A (SCC of the hypopharynx) cells, as well as various other HNSCC cell lines, with C6-Pyr-Cer resulted in the inhibition of cell survival with an IC50 concentration of approximately 250 to 300 nM at 96 hours, whereas its IC50 was greater than 1000 nM in noncancerous Wi-38 human lung fibroblasts, and adult human epidermal keratinocytes. Moreover, treatment with C6-Pyr-Cer also resulted in cell cycle arrest in G0/G1, which correlated with a significant inhibition of telomerase activity in UM-SCC-22A cells. Additional results demonstrated that the combination of C6-Pyr-Cer with gemcitabine (GMZ) or doxorubicin (DOX), which have the lowest IC50 concentrations among various chemotherapeutic drugs in these cells, enhances the effects of these drugs in the inhibition of telomerase and cell growth. CONCLUSIONS These data suggest that the novel C6-Pyr-Cer with high solubility and bioavailability may lead to the development of new therapeutic strategies that target telomerase for the treatment of HNSCC.
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Affiliation(s)
- Michael J Rossi
- Department of Biochemistry and Molecular Biology, Medical University of South Carolina, Charleston, USA
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17
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O'Brien R, Tran SL, Maritz MF, Liu B, Kong CF, Purgato S, Yang C, Murray J, Russell AJ, Flemming CL, von Jonquieres G, Pickett HA, London WB, Haber M, Gunaratne PH, Norris MD, Perini G, Fletcher JI, MacKenzie KL. MYC-Driven Neuroblastomas Are Addicted to a Telomerase-Independent Function of Dyskerin. Cancer Res 2016; 76:3604-17. [PMID: 27197171 DOI: 10.1158/0008-5472.can-15-0879] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2015] [Accepted: 03/14/2016] [Indexed: 11/16/2022]
Abstract
The RNA-binding protein dyskerin, encoded by the DKC1 gene, functions as a core component of the telomerase holoenzyme as well as ribonuclear protein complexes involved in RNA processing and ribosome biogenesis. The diverse roles of dyskerin across many facets of RNA biology implicate its potential contribution to malignancy. In this study, we examined the expression and function of dyskerin in neuroblastoma. We show that DKC1 mRNA levels were elevated relative to normal cells across a panel of 15 neuroblastoma cell lines, where both N-Myc and c-Myc directly targeted the DKC1 promoter. Upregulation of MYCN was shown to dramatically increase DKC1 expression. In two independent neuroblastoma patient cohorts, high DKC1 expression correlated strongly with poor event-free and overall survival (P < 0.0001), independently of established prognostic factors. RNAi-mediated depletion of dyskerin inhibited neuroblastoma cell proliferation, including cells immortalized via the telomerase-independent ALT mechanism. Furthermore, dyskerin attenuation impaired anchorage-independent proliferation and tumor growth. Overexpression of the telomerase RNA component, hTR, demonstrated that this proliferative impairment was not a consequence of telomerase suppression. Instead, ribosomal stress, evidenced by depletion of small nucleolar RNAs and nuclear dispersal of ribosomal proteins, was the likely cause of the proliferative impairment in dyskerin-depleted cells. Accordingly, dyskerin suppression caused p53-dependent G1 cell-cycle arrest in p53 wild-type cells, and a p53-independent pathway impaired proliferation in cells with p53 dysfunction. Together, our findings highlight dyskerin as a new therapeutic target in neuroblastoma with crucial telomerase-independent functions and broader implications for the spectrum of malignancies driven by MYC family oncogenes. Cancer Res; 76(12); 3604-17. ©2016 AACR.
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Affiliation(s)
- Rosemary O'Brien
- Children's Cancer Institute Australia, Randwick, Sydney, New South Wales, Australia
| | - Sieu L Tran
- Children's Cancer Institute Australia, Randwick, Sydney, New South Wales, Australia
| | - Michelle F Maritz
- Children's Cancer Institute Australia, Randwick, Sydney, New South Wales, Australia
| | - Bing Liu
- Children's Cancer Institute Australia, Randwick, Sydney, New South Wales, Australia
| | - Cheng Fei Kong
- Children's Cancer Institute Australia, Randwick, Sydney, New South Wales, Australia
| | - Stefania Purgato
- Department of Pharmacy and Biotechnology, University of Bologna, Bologna, Italy
| | - Chen Yang
- Children's Cancer Institute Australia, Randwick, Sydney, New South Wales, Australia
| | - Jayne Murray
- Children's Cancer Institute Australia, Randwick, Sydney, New South Wales, Australia
| | - Amanda J Russell
- Children's Cancer Institute Australia, Randwick, Sydney, New South Wales, Australia
| | - Claudia L Flemming
- Children's Cancer Institute Australia, Randwick, Sydney, New South Wales, Australia
| | - Georg von Jonquieres
- Children's Cancer Institute Australia, Randwick, Sydney, New South Wales, Australia
| | - Hilda A Pickett
- Telomere Length Regulation Laboratory, Children's Medical Research Institute, Westmead, New South Wales, Australia
| | - Wendy B London
- Dana-Farber/Boston Children's Cancer and Blood Disorders Center, Boston, Massachusetts
| | - Michelle Haber
- Children's Cancer Institute Australia, Randwick, Sydney, New South Wales, Australia
| | - Preethi H Gunaratne
- Department of Biology and Biochemistry, University of Houston, Houston, Texas
| | - Murray D Norris
- Children's Cancer Institute Australia, Randwick, Sydney, New South Wales, Australia
| | - Giovanni Perini
- Department of Pharmacy and Biotechnology, University of Bologna, Bologna, Italy
| | - Jamie I Fletcher
- Children's Cancer Institute Australia, Randwick, Sydney, New South Wales, Australia
| | - Karen L MacKenzie
- Children's Cancer Institute Australia, Randwick, Sydney, New South Wales, Australia.
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18
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Abstract
Telomerase catalyzes telomeric DNA synthesis, an essential process to maintain the length of telomere for continuous cell proliferation and genomic stability. Telomerase is activated in gametes, stem cells, and most tumor cells, and its activity is tightly controlled by a catalytic human telomerase reverse transcriptase (hTERT) subunit and a collection of associated proteins. In the present work, normal human testis tissue was used for the first time to identify proteins involved in the telomerase regulation under normal physiological conditions. Immunoprecipitation was performed using total protein lysates from the normal testis tissue and the proteins of interest were identified by microfluidic high-performance liquid chromatography and tandem mass spectrometry (HPLC-Chip-MS/MS). The regulatory role of PCDH10 in telomerase activity was confirmed by a telomeric repeat amplification protocol (TRAP) assay, and the biological functions of it were characterized by in vitro proliferation, migration, and invasion assays. A new in vivo hTERT interacting protein, protocadherin 10 (PCDH10), was identified. Overexpression of PCDH10 in pancreatic cancer cells impaired telomere elongation by inhibiting telomerase activity while having no obvious effect on hTERT expression at mRNA and protein levels. As a result of this critical function in telomerase regulation, PCDH10 was found to inhibit cell proliferation, migration, and invasion, suggesting a tumor suppressive role of this protein. Our data suggested that PCDH10 played a critical role in cancer cell growth, by negatively regulating telomerase activity, implicating a potential value in future therapeutic development against cancer.
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Affiliation(s)
- Li-Na Zhou
- From the Department of Endocrinology (L-NZ, W-QD, Q-NW, BC); Department of Ultrasound, Southwest Hospital, The Third Military Medical University, Chongqing, China (XH); and Biostatistics, Yale New Haven Health Services Corporation Center for Outcomes Research and Evaluation, New Haven, CT (HM)
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19
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Abstract
The enzymatic ribonucleoprotein telomerase maintains telomeres in many eukaryotes, including humans, and plays a central role in aging and cancer. Saccharomyces cerevisiae telomerase RNA, TLC1, is a flexible scaffold that tethers telomerase holoenzyme protein subunits to the complex. Here we test the hypothesis that a lengthy conserved region of the Est1-binding TLC1 arm contributes more than simply Est1-binding function. We separated Est1 binding from potential other functions by tethering TLC1 to Est1 via a heterologous RNA-protein binding module. We find that Est1-tethering rescues in vivo function of telomerase RNA alleles missing nucleotides specifically required for Est1 binding, but not those missing the entire conserved region. Notably, however, telomerase function is restored for this condition by expressing the arm of TLC1 in trans. Mutational analysis shows that the Second Essential Est1-arm Domain (SEED) maps to an internal loop of the arm, which SHAPE chemical mapping and 3D modeling suggest could be regulated by conformational change. Finally, we find that the SEED has an essential, Est1-independent role in telomerase function after telomerase recruitment to the telomere. The SEED may be required for establishing telomere extendibility or promoting telomerase RNP holoenzyme activity.
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Affiliation(s)
- Kevin J Lebo
- Department of Biology, Johns Hopkins University, Baltimore, Maryland 21218-2685, USA
| | - Rachel O Niederer
- Department of Biology, Johns Hopkins University, Baltimore, Maryland 21218-2685, USA
| | - David C Zappulla
- Department of Biology, Johns Hopkins University, Baltimore, Maryland 21218-2685, USA
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20
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Koh CM, Khattar E, Leow SC, Liu CY, Muller J, Ang WX, Li Y, Franzoso G, Li S, Guccione E, Tergaonkar V. Telomerase regulates MYC-driven oncogenesis independent of its reverse transcriptase activity. J Clin Invest 2015; 125:2109-22. [PMID: 25893605 PMCID: PMC4463203 DOI: 10.1172/jci79134] [Citation(s) in RCA: 119] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2014] [Accepted: 03/12/2015] [Indexed: 12/25/2022] Open
Abstract
Constitutively active MYC and reactivated telomerase often coexist in cancers. While reactivation of telomerase is thought to be essential for replicative immortality, MYC, in conjunction with cofactors, confers several growth advantages to cancer cells. It is known that the reactivation of TERT, the catalytic subunit of telomerase, is limiting for reconstituting telomerase activity in tumors. However, while reactivation of TERT has been functionally linked to the acquisition of several "hallmarks of cancer" in tumors, the molecular mechanisms by which this occurs and whether these mechanisms are distinct from the role of telomerase on telomeres is not clear. Here, we demonstrated that first-generation TERT-null mice, unlike Terc-null mice, show delayed onset of MYC-induced lymphomagenesis. We further determined that TERT is a regulator of MYC stability in cancer. TERT stabilized MYC levels on chromatin, contributing to either activation or repression of its target genes. TERT regulated MYC ubiquitination and proteasomal degradation, and this effect of TERT was independent of its reverse transcriptase activity and role in telomere elongation. Based on these data, we conclude that reactivation of TERT, a direct transcriptional MYC target in tumors, provides a feed-forward mechanism to potentiate MYC-dependent oncogenesis.
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MESH Headings
- Animals
- Cell Line, Tumor
- Cell Transformation, Neoplastic/genetics
- Enzyme Activation
- Feedback, Physiological
- Gene Expression Regulation, Neoplastic/genetics
- Genes, myc
- Glycogen Synthase Kinase 3/physiology
- Glycogen Synthase Kinase 3 beta
- Heterografts
- Humans
- Lymphoma, Non-Hodgkin/pathology
- Mice
- Mice, Inbred C57BL
- Mice, Knockout
- Neoplasm Proteins/genetics
- Neoplasm Proteins/metabolism
- Neoplasm Proteins/physiology
- Neoplasm Transplantation
- Phosphorylation
- Promoter Regions, Genetic
- Protein Processing, Post-Translational
- Protein Stability
- Proto-Oncogene Proteins c-myc/genetics
- Proto-Oncogene Proteins c-myc/metabolism
- Proto-Oncogene Proteins c-myc/physiology
- RNA/genetics
- RNA/physiology
- RNA Interference
- Telomerase/deficiency
- Telomerase/genetics
- Telomerase/physiology
- Telomere Homeostasis/genetics
- Time Factors
- Transcription, Genetic
- Ubiquitination
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Affiliation(s)
- Cheryl M. Koh
- Division of Cancer Genetics and Therapeutics, Laboratory of Methyltransferases in Development and Disease, and
| | - Ekta Khattar
- Division of Cancer Genetics and Therapeutics, Laboratory of NF-κB Signaling, Institute of Molecular and Cell Biology, Agency for Science, Technology and Research (A*STAR), Singapore
| | - Shi Chi Leow
- Division of Cancer Genetics and Therapeutics, Laboratory of NF-κB Signaling, Institute of Molecular and Cell Biology, Agency for Science, Technology and Research (A*STAR), Singapore
| | - Chia Yi Liu
- Division of Cancer Genetics and Therapeutics, Laboratory of NF-κB Signaling, Institute of Molecular and Cell Biology, Agency for Science, Technology and Research (A*STAR), Singapore
| | - Julius Muller
- Division of Cancer Genetics and Therapeutics, Laboratory of Methyltransferases in Development and Disease, and
| | - Wei Xia Ang
- Division of Cancer Genetics and Therapeutics, Laboratory of Methyltransferases in Development and Disease, and
| | - Yinghui Li
- Division of Cancer Genetics and Therapeutics, Laboratory of NF-κB Signaling, Institute of Molecular and Cell Biology, Agency for Science, Technology and Research (A*STAR), Singapore
| | - Guido Franzoso
- Department of Medicine, Imperial College London, London, United Kingdom
| | - Shang Li
- Program in Cancer and Stem Cell Biology, Duke-NUS Graduate Medical School, Singapore
- Department of Physiology and
| | - Ernesto Guccione
- Division of Cancer Genetics and Therapeutics, Laboratory of Methyltransferases in Development and Disease, and
- Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
| | - Vinay Tergaonkar
- Division of Cancer Genetics and Therapeutics, Laboratory of NF-κB Signaling, Institute of Molecular and Cell Biology, Agency for Science, Technology and Research (A*STAR), Singapore
- Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
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21
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Spivak IM, Mikhelson VM, Spivak DL. [Telomere length, telomerase activity, stress and aging]. Adv Gerontol 2015; 28:441-448. [PMID: 28509478] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
The review is dedicated to analysis of data available at present time concerning possible influence of stress upon telomere lengths and telomerase activity, as well as various ways of counteracting it. Present-day telomerase theory of aging gains a new impetus, shedding light upon the influence of psychological state of humans and their ability to counteract stress, upon the process of aging. It also tends to regard telomere shortening and the decrease in the activity of telomerase as a marker of level of the ability to adapt to both inner and outer influences. Both aging and age-dependent diseases are proved to be substantially retarded not only by the administration of drugs, but also by psychological means, which forms a good way towards healthy longevity. With complete understanding of the impossibility to prevent or even to slow down natural senescence itself, these methods allow to remove causes, which accelerate senescence, and to increase the average human longevity.
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Affiliation(s)
- I M Spivak
- Institute of Cytology, RAS, Saint-Petersburg, 194064, Russian Federation
- Saint-Petersburg State University, Saint-Petersburg, 199034, Russian Federation
- Saint-Petersburg State Polytechnical University, Saint-Petersburg, 195251, Russian Federation
| | - V M Mikhelson
- Institute of Cytology, RAS, Saint-Petersburg, 194064, Russian Federation
- Saint-Petersburg State Polytechnical University, Saint-Petersburg, 195251, Russian Federation
| | - D L Spivak
- Institute of Human Brain, RAS, Saint-Petersburg, 197376, Russian Federation;
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22
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Hu Y, Gu YH, Zhang HR, Xu HQ. [Progress of researches on protective effect of moxibustion on myocardial cells during exhaustive exercise ]. Zhen Ci Yan Jiu 2014; 39:504-507. [PMID: 25632579] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Moxibustion is a side-effect-free external therapy for relieving different clinical disorders. Its effects in eliminating sports fatigue, preventing myocardial injury in people undergeing exhausted exercise and its underlying mechanisms have been induced great concern by the sports medicine community. In the present paper, the authors make a review on the development of researches on the underlying mechanism of moxibustion in the prevention and treatment of sports myocardial injury in re- cent 10 years from 1) regulating myocardial endocrine function, 2) scavenging free radicals, 3) resisting oxidative damage, and 4) modulating blood rheology. On the basis of results mentioned above, the authors raise a new potential mechanism underlying protective effect of moxibustion on myocardial cells during exhaustive exercise from the cellular molecular level, i.e., mitochondrial telomerase-mediated anti-aging. This mitochondrial telomerase-mediated anti-aging may be a new target of moxibustion intervention for protecting cardiomyocytes from injury under exhaustive exercise condition.
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Bennaceur K, Atwill M, Al Zhrany N, Hoffmann J, Keavney B, Breault D, Richardson G, von Zglinicki T, Saretzki G, Spyridopoulos I. Atorvastatin induces T cell proliferation by a telomerase reverse transcriptase (TERT) mediated mechanism. Atherosclerosis 2014; 236:312-20. [PMID: 25127175 DOI: 10.1016/j.atherosclerosis.2014.07.020] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/20/2014] [Revised: 07/18/2014] [Accepted: 07/21/2014] [Indexed: 12/12/2022]
Abstract
UNLABELLED Statins are one of the most potent drugs in delaying age-related inflammatory changes in the arterial vessel wall, slowing down the progression of atherosclerosis. Statins have also been shown to abrogate telomere-attributed cardiovascular risk. The goal of our study was to explore a potential effect of atorvastatin on telomerase activity in peripheral blood mononuclear cells (PBMCs) and T-lymphocytes (T cells). METHODS AND RESULTS Treatment with pharmacologically relevant concentrations (0.1-0.3 μM) of atorvastatin resulted in a 6-fold increase of telomerase activity (TA) (p < 0.0001) in human and mouse PBMCs and CD4 T cells, translating into moderate proliferation of T lymphocytes. In contrast, high doses of atorvastatin (2-5 μM) or the addition of LDL cholesterol completely inhibited proliferation, thereby abrogating telomerase activity. The proliferative effect of atorvastatin was ablated by the absense of the catalytic subunit of telomerase, telomerase reverse transcriptase (TERT). Using transgenic GFP-mTert reporter mice, we observed a decrease in telomerase-positive lymphocytes from 30% to 15% during the first 5 months of age (p < 0.01). This suggests that the decrease in immune cell turnover during normal development and maturation is mirrored by a reduction in telomerase activity in lymphocytes in-vivo. CONCLUSION Atorvastatin and cholesterol have opposing effects on telomerase in mononuclear cells and T-lymphocytes. Our study suggests a link between cholesterol metabolism and telomere-related cardiovascular risk.
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Affiliation(s)
| | - Mark Atwill
- Institute of Genetic Medicine at Newcastle University, UK
| | | | | | | | - David Breault
- Department of Pediatrics, Childrens Hospital and Harvard Stem Cell Institute, Cambridge, Boston, MA, USA
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Saeed H, Iqtedar M. Bone Marrow Stromal Cell (BMSC) and skeletal aging: role of telomerase enzyme. Pak J Pharm Sci 2014; 27:321-333. [PMID: 24577922] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Telomere shortening and telomerase deficiency have been linked with several age related degenerative diseases. Moreover, degenerative changes in various tissues/organs have been attributed to derangement of stem cell functions causing regenerative tragedy. Bone marrow stromal cells (BMSCs) are considered the ideal candidates for regenerative approaches owing to their beneficial effects in numerous clinical applications. Thus, the effect of telomerase deficiency in perpetrating age related changes in BMSC functions during in vitro culture; their morphology, proliferation and differentiation, that can be extrapolated and reasoned for skeletal aging is conversed in this review. Besides, information regarding pertinent molecular and biochemical markers that can be employed to examine the earliest events, during the course of BMSC aging, is also provided. Additionally, impact of telomerase deficiency in enacting skeletal aging phenotype and its associated microenvironment is also discussed. In the end, further studies, using tissue specific models of telomerase deficiency, are recommended as a future research strategy to advance our understanding of tissue specific telomerase regulation.
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Affiliation(s)
- Hamid Saeed
- Department of Endocrinology, School of Medicine, Stanford University, CA, United States
| | - Mehwish Iqtedar
- Department of Bio-technology & Microbiology, Lahore College for Women University, Lahore, Pakistan
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25
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Park HH, Lee KY, Kim S, Lee JW, Choi NY, Lee EH, Lee YJ, Lee SH, Koh SH. Novel vaccine peptide GV1001 effectively blocks β-amyloid toxicity by mimicking the extra-telomeric functions of human telomerase reverse transcriptase. Neurobiol Aging 2013; 35:1255-74. [PMID: 24439482 DOI: 10.1016/j.neurobiolaging.2013.12.015] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2013] [Revised: 11/21/2013] [Accepted: 12/19/2013] [Indexed: 12/17/2022]
Abstract
GV1001 is a 16-amino-acid vaccine peptide derived from the human telomerase reverse transcriptase sequence. We investigated the effects of GV1001 against β-amyloid (Aβ) oligomer-induced neurotoxicity in rat neural stem cells (NSCs). Primary culture NSCs were treated with several concentrations of GV1001 and/or Aβ₂₅₋₃₅ oligomer for 48 hours. GV1001 protected NSCs against the Aβ₂₅₋₃₅ oligomer in a concentration-dependent manner. Aβ₂₅₋₃₅ concentration dependently decreased viability, proliferation, and mobilization of NSCs and GV1001 treatment restored the cells to wild-type levels. Aβ₂₅₋₃₅ increased free radical levels in rat NSCs while combined treatment with GV1001 significantly reduced these levels. In addition, GV1001 treatment of Aβ₂₅₋₃₅-injured NSCs increased the expression level of survival-related proteins, including mitochondria-associated survival proteins, and decreased the levels of death and inflammation-related proteins, including mitochondria-associated death proteins. Together, these results suggest that GV1001 possesses neuroprotective effects against Aβ₂₅₋₃₅ oligomer in NSCs and that these effects are mediated through mimicking the extra-telomeric functions of human telomerase reverse transcriptase, including the induction of cellular proliferation, anti-apoptotic effects, mitochondrial stabilization, and anti-aging and anti-oxidant effects.
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Affiliation(s)
- Hyun-Hee Park
- Department of Neurology, Hanyang University College of Medicine, Guri, Gyeonggi, Korea
| | - Kyu-Yong Lee
- Department of Neurology, Hanyang University College of Medicine, Guri, Gyeonggi, Korea
| | - Sangjae Kim
- Department of Neuroscience, KAEL-Gemvax Co, Ltd, Seoul, Korea
| | | | - Na-Young Choi
- Department of Translational Medicine, Hanyang University Graduate School of Biomedical Science & Engineering, Seoul, Korea
| | - Eun-Hye Lee
- Department of Translational Medicine, Hanyang University Graduate School of Biomedical Science & Engineering, Seoul, Korea
| | - Young Joo Lee
- Department of Neurology, Hanyang University College of Medicine, Guri, Gyeonggi, Korea
| | - Sang-Hun Lee
- Department of Biochemistry and Molecular Biology, Hanyang University College of Medicine, Seoul, Korea
| | - Seong-Ho Koh
- Department of Neurology, Hanyang University College of Medicine, Guri, Gyeonggi, Korea; Department of Translational Medicine, Hanyang University Graduate School of Biomedical Science & Engineering, Seoul, Korea.
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26
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Pal J, Gold JS, Munshi NC, Shammas MA. Biology of telomeres: importance in etiology of esophageal cancer and as therapeutic target. Transl Res 2013; 162:364-70. [PMID: 24090770 PMCID: PMC3834232 DOI: 10.1016/j.trsl.2013.09.003] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/21/2013] [Revised: 09/05/2013] [Accepted: 09/06/2013] [Indexed: 11/17/2022]
Abstract
The purpose of this review is to highlight the importance of telomeres, the mechanisms implicated in their maintenance, and their role in the etiology as well as the treatment of human esophageal cancer. We will also discuss the role of telomeres in the maintenance and preservation of genomic integrity, the consequences of telomere dysfunction, and the various factors that may affect telomere health in esophageal tissue predisposing it to oncogenesis. There has been growing evidence that telomeres, which can be affected by various intrinsic and extrinsic factors, contribute to genomic instability, oncogenesis, as well as proliferation of cancer cells. Telomeres are the protective DNA-protein complexes at chromosome ends. Telomeric DNA undergoes progressive shortening with age leading to cellular senescence and/or apoptosis. If senescence/apoptosis is prevented as a consequence of specific genomic changes, continued proliferation leads to very short (ie, dysfunctional) telomeres that can potentially cause genomic instability, thus, increasing the risk for activation of telomere maintenance mechanisms and oncogenesis. Like many other cancers, esophageal cancer cells have short telomeres and elevated telomerase, the enzyme that maintains telomeres in most cancer cells. Homologous recombination, which is implicated in the alternate pathway of telomere elongation, is also elevated in Barrett's-associated esophageal adenocarcinoma. Evidence from our laboratory indicates that both telomerase and homologous recombination contribute to telomere maintenance, DNA repair, and the ongoing survival of esophageal cancer cells. This indicates that telomere maintenance mechanisms may potentially be targeted to make esophageal cancer cells static. The rate at which telomeres in healthy cells shorten is determined by a number of intrinsic and extrinsic factors, including those associated with lifestyle. Avoidance of factors that may directly or indirectly injure esophageal tissue including its telomeric and other genomic DNA can not only reduce the risk of development of esophageal cancer but may also have positive impact on overall health and lifespan.
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Affiliation(s)
- Jagannath Pal
- Harvard (Dana Farber) Cancer Institute, Boston, MA, USA
- VA Boston Healthcare System, Boston, MA, USA
| | - Jason S. Gold
- Harvard (Dana Farber) Cancer Institute, Boston, MA, USA
- Harvard Medical School, Boston, MA, USA
- Brigham and Women’s Hospital, Boston, MA, USA
- VA Boston Healthcare System, Boston, MA, USA
| | - Nikhil C. Munshi
- Harvard (Dana Farber) Cancer Institute, Boston, MA, USA
- Harvard Medical School, Boston, MA, USA
- VA Boston Healthcare System, Boston, MA, USA
| | - Masood A. Shammas
- Harvard (Dana Farber) Cancer Institute, Boston, MA, USA
- VA Boston Healthcare System, Boston, MA, USA
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27
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Katsumi S, Kawauchi K, Ozaki K, Shimizu S, Kimura T, Motoji T, Yamada O. [Analysis of molecular mechanism involved in development of acute myeloid leukemia]. Gan To Kagaku Ryoho 2013; 40:471-477. [PMID: 23848014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
We examined the role of molecules related to drug resistance, such as P-glycoprotein (P-gp) and telomerase (TERT), signaling molecules of STATs and FLT3 in leukemia pathogenesis in de novo acute myeloid leukemia (AML), and myelodysplastic syndrome in the phase of overt leukemia (MDS-OL). Subjects were 18 patients with de novo AML, in which expression of P-gp, TERT, STAT3, STAT5, and FLT3 was observed in 11, 14, 16, 18, and 14 of patients, respectively. Phosphorylation of STAT3, STAT5, and FLT3 in patients with de novo AML was observed in 10 out of 14, 14 out of 18, and 10 out of 14 patients, respectively. Phosphorylation of STAT5 was associated with expression of both P-gp and TERT, suggesting that STAT5 is one of the transcription factors for these genes. On the other hand, P-gp, TERT, STAT3, STAT5, and FLT3 were expressed in 3, 1, 1, 6, and 1 of the 7 patients with MDS-OL, respectively. While phosphorylation of STAT5 was observed in 4 out of 7 patients, phosphorylation of STAT3 or FLT3 was not detected in all cases examined. Telomere length varied from 2.7 kb to 6.0 kb in de novo AML, accompanied by an increased level of telomerase activity in 4 of 5 patients with de novo AML. In contrast, all MDS-OL cases showed a similar telomere length of 4-5 kb. These results indicate that consideration should be given to the differences of molecular mechanisms in the pathogenesis of de novo AML and MDS-OL for the treatment strategy of AML.
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Smith MC, Goddard ET, Perusina Lanfranca M, Davido DJ. hTERT extends the life of human fibroblasts without compromising type I interferon signaling. PLoS One 2013; 8:e58233. [PMID: 23472163 PMCID: PMC3589264 DOI: 10.1371/journal.pone.0058233] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2012] [Accepted: 02/05/2013] [Indexed: 12/24/2022] Open
Abstract
Primary cells are often used to study viral replication and host-virus interactions as their antiviral pathways have not been altered or inactivated; however, their use is restricted by their short lifespan. Conventional methods to extend the life of primary cultures typically utilize viral oncogenes. Many of these oncogenes, however, perturb or inactivate cellular antiviral pathways, including the interferon (IFN) response. It has been previously shown that expression of the telomerase reverse transcriptase (TERT) gene extends the life of certain cell types. The effect that TERT expression has on the innate antiviral response to RNA- and DNA-containing viruses has not been examined. In the current study, we introduced the human TERT (hTERT) gene into a primary human embryonic lung (HEL-299) cell strain, which is known to respond to the type I IFN, IFN-β. We show that the resulting HEL-TERT cell line is capable of replicating beyond 100 population doublings without exhibiting signs of senescence. Treatment with IFN-β resulted in the upregulation of four model IFN stimulated genes (ISGs) in HEL-299 and HEL-TERT cells. Both cell lines supported the replication of herpes simplex virus type 1 (HSV-1) and vesicular stomatitis virus (VSV) and impaired the replication of both viruses upon IFN-β pretreatment. Introduction of the viral oncoprotein, simian virus 40 (SV40) large T-antigen, which is frequently used to immortalize cells, largely negated this effect. Taken together, our data indicate that expression of hTERT does not alter type 1 IFN signaling and/or the growth of two viruses, making this cell line a useful reagent for studying viral replication and virus-cell interactions.
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Affiliation(s)
- Miles C. Smith
- Department of Molecular Biosciences, University of Kansas, Lawrence, Kansas, United States of America
| | - Erica T. Goddard
- Department of Molecular Biosciences, University of Kansas, Lawrence, Kansas, United States of America
| | - Mirna Perusina Lanfranca
- Department of Molecular Biosciences, University of Kansas, Lawrence, Kansas, United States of America
| | - David J. Davido
- Department of Molecular Biosciences, University of Kansas, Lawrence, Kansas, United States of America
- * E-mail:
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29
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Jung AR, Yoo JE, Shim YH, Choi YN, Jeung HC, Chung HC, Rha SY, Oh BK. Increased alternative lengthening of telomere phenotypes of telomerase-negative immortal cells upon trichostatin--a treatment. Anticancer Res 2013; 33:821-829. [PMID: 23482750] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Human immortal cells maintain their telomeres either by telomerase or by alternative lengthening of telomeres (ALT) that is based on homologous telomeric recombination. Previous studies showed that the ALT mechanism is activated in non-ALT cells when heterochromatic features are reduced. In this study, we examined the ALT phenotypes of ALT cells after treatment with trichostatin-A (TSA), which is an inhibitor of histone deacetylases and causes global chromatin decondensation. The ALT cells remained telomerase-negative after TSA treatment. ALT-associated promyelocytic leukemia (PML) nuclear bodies and telomere sister chromatid exchanges, typical ALT phenotypes, markedly increased in the TSA-treated cells, while the telomere length remained unchanged. In addition, telomerase expression in the ALT cells suppressed TSA-mediated ALT phenotype enhancement. Our results show that certain ALT phenotypes become more pronounced when chromatin is decondensed, and also suggest that the ALT mechanism may compete with telomerase for telomere maintenance in cells that lack heterochromatin.
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Affiliation(s)
- A Ra Jung
- Department of Bioscience and Biotechnology, Brain Korea 21 Division of Bioscience and Biotechnology, Konkuk University, Seoul 143-701, Republic of Korea
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Flores SC, Zemora G, Waldsich C. Insights into diseases of human telomerase from dynamical modeling. Pac Symp Biocomput 2013:200-211. [PMID: 23424125] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Mutations in the telomerase complex disrupt either nucleic acid binding or catalysis, and are the cause of numerous human diseases. Despite its importance, the structure of the human telomerase complex has not been observed crystallographically, nor are its dynamics understood in detail. Fragments of this complex from Tetrahymena thermophila and Tribolium castaneum have been crystallized. Biochemical probes provide important insight into dynamics. In this work we summarize evidence that the T. castaneum structure is Telomerase Reverse Transcriptase. We use this structure to build a partial model of the human Telomerase complex. The model suggests an explanation for the structural role of several disease-associated mutations. We then generate a 3D kinematic trajectory of telomere elongation to illustrate a "typewriter" mechanism: the RNA template moves to keep the end of the growing telomeric primer in the active site, disengaging after every 6-residue extension to execute a "carriage return" and go back to its starting position. A hairpin can easily form in the primer, from DNA residues leaving the primer-template duplex. The trajectory is consistent with available experimental evidence. The methodology is extensible to many problems in structural biology in general and personalized medicine in particular.
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Affiliation(s)
- Samuel Coulbourn Flores
- Cell and Molecular Biology Department, Uppsala University, Biomedical Center, Box 596, 75124 Uppsala, Sweden.
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Zhang Z, Wang J, Li J, Xu S. Telomerase-mediated apoptosis of chicken lymphoblastoid tumor cell line by lanthanum chloride. Biol Trace Elem Res 2011; 144:657-67. [PMID: 21448564 DOI: 10.1007/s12011-011-9027-8] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/13/2010] [Accepted: 03/08/2011] [Indexed: 11/25/2022]
Abstract
To investigate the biological effects of lanthanum on chicken lymphoid tumors, cultures of the MDCC-MSB1 chicken lymphoblastoid cell line were treated with 2.5 mM lanthanum chloride for 2 days at 12-h intervals. The apoptotic cells were detected using the TdT-mediated dUTP nick end labeling assay and flow cytometer analysis. The telomerase activity and the chTERT mRNA expression levels of the MDCC-MSB1 cells were examined. The results showed that MDCC-MSB1 cell apoptosis occurred after incubation for 12 to 48 h induced by 2.5 mM LaCl(3). Consistent with the apoptosis results, telomerase activities in LaCl(3)-treated cells significantly decreased (P < 0.05) compared with 0 h group. Furthermore, the transcription of chTERT gene in MDCC-MSB1 cell was significantly inhibited in LaCl(3) treatment group (P < 0.05). These results suggest that the decrease of the chTERT transcription and telomerase activity play an important role in the La-induced apoptosis in chicken lymphoid tumor.
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Affiliation(s)
- Ziwei Zhang
- College of Veterinary Medicine, Northeast Agricultural University, Harbin, 150030, People's Republic of China.
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Xu T, He K, Wang L, Goldkorn A. Prostate tumor cells with cancer progenitor properties have high telomerase activity and are rapidly killed by telomerase interference. Prostate 2011; 71:1390-400. [PMID: 21321978 PMCID: PMC3123672 DOI: 10.1002/pros.21355] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/06/2010] [Accepted: 01/14/2011] [Indexed: 01/06/2023]
Abstract
BACKGROUND Cancer progenitor cells (CPCs) have been postulated to promote treatment resistance and disease progression in prostate and other malignancies. We investigated whether the enzyme telomerase, which is active in cancer cells and in normal stem cells, plays an important role in CPC which can be exploited to neutralize these cells. METHODS We used flow cytometry and assays of gene expression, clonogenicity, and invasiveness to isolate and characterize a putative CPC subpopulation from freshly resected human prostatectomy specimens. Telomerase activity was measured by qPCR-based Telomeric Repeat Amplification Protocol (TRAP). Telomerase interference was achieved by ectopic expression of a mutated telomerase RNA construct which reprograms telomerase to generate "toxic" uncapped telomeres. Treated cells were assayed for apoptosis, proliferation in culture, and xenograft tumor formation. RESULTS CPC in prostate tumors expressed elevated levels of genes associated with a progenitor phenotype and were highly clonogenic and invasive. Significantly, CPC telomerase activity was 20- to 200-fold higher than in non-CPC from the same tumors, and CPC were exquisitely sensitive to telomerase interference which induced rapid apoptosis and growth inhibition. Similarly, induction of telomerase interference in highly tumorigenic CPC isolated from a prostate cancer cell line abrogated their ability to form tumor xenografts. CONCLUSIONS Human prostate tumors contain a CPC subpopulation with markedly elevated telomerase activity which renders them acutely susceptible to telomerase interference. These findings offer the first tumor-derived and in vivo evidence that telomerase may constitute a CPC "Achilles heel" which may ultimately form the basis for more effective new CPC-targeting therapies.
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Affiliation(s)
- Tong Xu
- Division of Medical Oncology, Department of Internal Medicine, University of Southern California Keck School of Medicine and Norris Comprehensive Cancer Center, Los Angeles, CA 90033
| | - Kaijie He
- Division of Medical Oncology, Department of Internal Medicine, University of Southern California Keck School of Medicine and Norris Comprehensive Cancer Center, Los Angeles, CA 90033
| | - Lina Wang
- Department of Pathology and Translational Pathology Core, University of Southern California Keck School of Medicine and Norris Comprehensive Cancer Center, Los Angeles, CA 90033
| | - Amir Goldkorn
- Division of Medical Oncology, Department of Internal Medicine, University of Southern California Keck School of Medicine and Norris Comprehensive Cancer Center, Los Angeles, CA 90033
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Newton JP. Anti-ageing--fact, fiction or faction? Gerodontology 2011; 28:163-4. [PMID: 21843158 DOI: 10.1111/j.1741-2358.2011.00532.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Printz C. New insights into telomeres, stress, and cancer risk. Cancer 2011; 117:2585. [PMID: 21656736 DOI: 10.1002/cncr.26259] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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35
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Xu Y, He K, Goldkorn A. Telomerase targeted therapy in cancer and cancer stem cells. Clin Adv Hematol Oncol 2011; 9:442-455. [PMID: 21841744] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Telomerase plays a key role in cell fate: loss of telomerase in normal differentiated cells heralds senescence and limits cell division, whereas reactivation of telomerase sustains proliferation and potentiates mutagenesis and transformation. Given this pivotal role, telomerase has been the subject of intense investigation in the field of developmental cancer therapeutics. To date, a broad spectrum of therapeutic strategies has been developed, ranging from direct targeting or reprogramming of the enzyme, to immune or virus-mediated targeting of cells expressing telomerase, to strategies focusing on the telomeres themselves. The recent discovery and growing interest in cancer stem cells has thrust telomerase therapy into new relief as an approach that may be uniquely suited to neutralizing this treatment-resistant subpopulation of cancer cells. Here we will review the mechanistic rationale and preclinical and clinical state of development of the various telomerase-based therapeutic approaches, with emphasis on the role of telomerase in cancer stem cell biology and its implications for therapeutic efforts.
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Affiliation(s)
- Yucheng Xu
- Division of Medical Oncology, Department of Internal Medicine, Norris Comprehensive Cancer Center, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA
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Sugio K, Sakurai F, Katayama K, Tashiro K, Matsui H, Kawabata K, Kawase A, Iwaki M, Hayakawa T, Fujiwara T, Mizuguchi H. Enhanced safety profiles of the telomerase-specific replication-competent adenovirus by incorporation of normal cell-specific microRNA-targeted sequences. Clin Cancer Res 2011; 17:2807-18. [PMID: 21346145 DOI: 10.1158/1078-0432.ccr-10-2008] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
PURPOSE Oncolytic adenoviruses (Ad) have been actively pursued as potential agents for cancer treatment. Among the various types of oncolytic Ads, the telomerase-specific replication-competent Ad (TRAD), which possesses an E1 gene expression cassette driven by the human telomerase reverse transcriptase promoter, has shown promising results in human clinical trials; however, the E1 gene is also slightly expressed in normal cells, leading to replication of TRAD and cellular toxicity in normal cells. EXPERIMENTAL DESIGN To overcome this problem, we utilized a microRNA (miRNA)-regulated gene expression system. Four copies of complementary sequences for miR-143, -145, -199a, or let-7a, which have been reported to be exclusively downregulated in tumor cells, were incorporated into the 3'-untranslated region of the E1 gene expression cassette. RESULTS Among the TRAD variants (herein called TRADs) constructed, TRADs containing the sequences complementary to miR-143, -145, or -199a showed efficient oncolytic activity comparable to the parental TRAD in the tumor cells. On the other hand, replication of the TRADs containing the miRNA complementary sequences was at most 1,000-fold suppressed in the normal cells, including primary normal cells. In addition, to suppress the replication of the TRADs in hepatocytes as well as other normal cells, we constructed a TRAD containing 2 distinct complementary sequences for miR-199a and liver-specific miR-122a (TRAD-122a/199aT). TRAD-122a/199aT exhibited more than 10-fold reduction in viral replication in all the normal cells examined, including primary hepatocytes. CONCLUSIONS This study showed that oncolytic Ads containing the sequences complementary to normal cell-specific miRNAs showed significantly improved safety profiles without altering tumor cell lysis activity.
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Affiliation(s)
- Kumiko Sugio
- Departments of Biochemistry and Molecular Biology and Biomedical Innovation, Graduate School of Pharmaceutical Sciences, Osaka University, Osaka, Japan
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Yi BQ, Zhao B, Wang ZJ. Comparison of clinicopathological features and hRad21 expression between telomerase-dependent and telomerase-independent colorectal cancer. Hepatogastroenterology 2011; 58:785-789. [PMID: 21830390] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
BACKGROUND/AIMS To investigate the difference of clinicopathological features and expression of hRad21 between telomerase-dependent and telomerase-independent colorectal cancer (CRC). METHODOLOGY By detecting telomerase activity of surgical specimens using the TRAP method, 251 cases diagnosed as CRC were allocated to the telomerase-dependent and telomerase-independent groups, as appropriate. Expression difference of hRad21 between the two groups was investigated by immunohistochemistry. All patients were followed-up and clinicopathological features were compared. RESULTS There were 38 and 213 cases in the telomerase-independent and telomerase-dependent groups, respectively. Expression of hRad21 in the telomerase-independent group is higher than that in the telomerase-dependent group. Clinicopathological analysis indicated that invasion of the rectal wall (T stage) in the telomerase-independent group was more superficial than that in the telomerase group (p=0.022). Age, gender, location of tumor, serum CEA, CA19-9, lymph node metastasis, distant metastasis, TNM stage and tumor differentiation showed no difference between groups. Follow-up indicated a significantly shortened survival time in the telomerase-dependent group (p=0.006). CONCLUSIONS Most CRC (84.9%) maintain their telomeres by telomerase, while a minority (15.1%) do so by telomerase-independent pathway. Depth of invasion in the telomerase-independent group was lower than that the telomerase group. Follow-up indicated that patients of telomerase-independent group had a higher survival rate than that of telomerase-dependent group. Expression of hRad21 in telomerase-independent CRC is higher than that of telomerase-dependent group, which suggested that hRad21 may be an important protein involved in telomerase-independent telomere maintenance mechanisms.
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Affiliation(s)
- Bing-Qiang Yi
- Department of General Surgery, Beijing Chaoyang Hospital, Capital Medical University, Beijing, China
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Chen J, Zhang B, Wong N, Lo AWI, To KF, Chan AWH, Ng MHL, Ho CYS, Cheng SH, Lai PBS, Yu J, Ng HK, Ling MT, Huang AL, Cai XF, Ko BCB. Sirtuin 1 is upregulated in a subset of hepatocellular carcinomas where it is essential for telomere maintenance and tumor cell growth. Cancer Res 2011; 71:4138-49. [PMID: 21527554 DOI: 10.1158/0008-5472.can-10-4274] [Citation(s) in RCA: 148] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Hepatocellular carcinoma (HCC) is a highly malignant tumor with a poor prognosis. Treatment of HCC is complicated by the fact that the disease is often diagnosed at an advanced stage when it is no longer amenable to curative surgery, and current systemic chemotherapeutics are mostly inefficacious. Sirtuin 1 (SIRT1) is a class III histone deacetylase that is implicated in gene regulations and stress resistance. In this study, we found that SIRT1 is essential for the tumorigenesis of HCC. We showed that although SIRT1 was expressed at very low levels in normal livers, it was overexpressed in HCC cell lines and in a subset of HCC. Tissue microarray analysis of HCC and adjacent nontumoral liver tissues revealed a positive correlation between the expression levels of SIRT1 and advancement in tumor grades. Downregulation of SIRT1 consistently suppressed the proliferation of HCC cells via the induction of cellular senescence or apoptosis. SIRT1 silencing also caused telomere dysfunction-induced foci and nuclear abnormality that were clearly associated with reduced expressions of telomerase reverse transcriptase (TERT), and PTOP, which is a member of the shelter in complex. Ectopic expression of either TERT or PTOP in SIRT1-depleted cells significantly restored cell proliferation. There was also a positive correlation between the level of induction of SIRT1 and TERT [corrected] in human HCC. Finally, SIRT1-silencing sensitized HCC cells to doxorubicin treatment. Together, our findings reveal a novel function for SIRT1 in telomere maintenance of HCC, and they rationalize the clinical exploration of SIRT1 inhibitors for HCC therapy.
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Affiliation(s)
- Juan Chen
- The State Key Laboratory in Oncology in South China, Li Ka Shing Institute of Health Sciences, The Chinese University of Hong Kong, Hong Kong, China
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Abstract
The peripheral retinal vascular abnormality which accompanies FSHD belongs morphologically and clinically to a class of developmental 'retinal hypovasculopathies' caused by abnormalities of 'Wnt' signalling, which controls retinal angiogenesis. Wnt signalling is also fundamental to myogenesis. This paper integrates modern concepts of myogenic cell signalling and of transcription factor expression and control with data from the classic early ophthalmic and myology embryology literature. Together, they support an hypothesis that abnormalities of Wnt signalling, which activates myogenic programs and transcription factors in myoblasts and satellite cells, leads to defective muscle regeneration in FSHD. The selective vulnerability of different FSHD muscles (notably facial muscle, from the second branchial arch) might reflect patterns of transcription factor redundancies. This hypothesis has implications for FSHD research through study of transcription factors patterning in normal human muscles, and for autologous cell transplantation.
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Wang HB, Wang WQ, Wang XW, Sun YG, Zhou G, Yang SM, Fan DC. PinX1 gene transfection enhances the sensitivity of gastric carcinoma cell line to 5-fluorouracil. Hepatogastroenterology 2011; 58:682-686. [PMID: 21661452] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
BACKGROUND/AIMS Since telomeres and telomerase play crucial roles in maintaining cell immortalization and cancer progression, they may be targets for anticancer treatment. PinX1 is a potent telomerase inhibitor, and a putative tumor suppressor. The use of PinX1 to treat cancers has not been reported yet. METHODOLOGY In order to use PinX1 in gene therapy for gastric carcinoma, we transfected PinX1 gene into the gastric carcinoma line MKN28 using the eukaryotic expression vector pIRES2-EGFP. PinX1-expressing, drug-resistant clones were screened with G418 and used in the study. RESULTS MKN28 cells transfected with PinX1 gene grew more slowly than the cells not transfected or transfected with void vectors (p<0.05). The IC50 value decreased markedly in cells transfected with PinX1 gene. PinX1 gene transfection enhanced the sensitivity of MKN28 cells to 5-fluorouracil (p<0.05). CONCLUSIONS PinX1 may be used in gene therapy for gastric carcinoma.
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Affiliation(s)
- Hong-Bin Wang
- Institute of Gastroenterology, Southwest Hospital, Third Military Medical University, Chongqing, China
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Mahmoudi S, Henriksson S, Weibrecht I, Smith S, Söderberg O, Strömblad S, Wiman KG, Farnebo M. WRAP53 is essential for Cajal body formation and for targeting the survival of motor neuron complex to Cajal bodies. PLoS Biol 2010; 8:e1000521. [PMID: 21072240 PMCID: PMC2970535 DOI: 10.1371/journal.pbio.1000521] [Citation(s) in RCA: 104] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2010] [Accepted: 09/03/2010] [Indexed: 02/02/2023] Open
Abstract
The WRAP53 gene gives rise to a p53 antisense transcript that regulates p53. This gene also encodes a protein that directs small Cajal body-specific RNAs to Cajal bodies. Cajal bodies are nuclear organelles involved in diverse functions such as processing ribonucleoproteins important for splicing. Here we identify the WRAP53 protein as an essential factor for Cajal body maintenance and for directing the survival of motor neuron (SMN) complex to Cajal bodies. By RNA interference and immunofluorescence we show that Cajal bodies collapse without WRAP53 and that new Cajal bodies cannot be formed. By immunoprecipitation we find that WRAP53 associates with the Cajal body marker coilin, the splicing regulatory protein SMN, and the nuclear import receptor importinβ, and that WRAP53 is essential for complex formation between SMN-coilin and SMN-importinβ. Furthermore, depletion of WRAP53 leads to accumulation of SMN in the cytoplasm and prevents the SMN complex from reaching Cajal bodies. Thus, WRAP53 mediates the interaction between SMN and associated proteins, which is important for nuclear targeting of SMN and the subsequent localization of the SMN complex to Cajal bodies. Moreover, we detect reduced WRAP53-SMN binding in patients with spinal muscular atrophy, which is the leading genetic cause of infant mortality worldwide, caused by mutations in SMN1. This suggests that loss of WRAP53-mediated SMN trafficking contributes to spinal muscular atrophy.
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Affiliation(s)
- Salah Mahmoudi
- Department of Oncology-Pathology, Cancer Centrum Karolinska, Karolinska Institutet, Stockholm, Sweden
| | - Sofia Henriksson
- Department of Oncology-Pathology, Cancer Centrum Karolinska, Karolinska Institutet, Stockholm, Sweden
| | - Irene Weibrecht
- Department of Genetics and Pathology, Rudbeck Laboratory, University of Uppsala, Uppsala, Sweden
| | - Stephen Smith
- Center for Biosciences, Department of Biosciences and Nutrition, Novum, Karolinska Institutet, Huddinge, Sweden
| | - Ola Söderberg
- Department of Genetics and Pathology, Rudbeck Laboratory, University of Uppsala, Uppsala, Sweden
| | - Staffan Strömblad
- Center for Biosciences, Department of Biosciences and Nutrition, Novum, Karolinska Institutet, Huddinge, Sweden
| | - Klas G. Wiman
- Department of Oncology-Pathology, Cancer Centrum Karolinska, Karolinska Institutet, Stockholm, Sweden
| | - Marianne Farnebo
- Department of Oncology-Pathology, Cancer Centrum Karolinska, Karolinska Institutet, Stockholm, Sweden
- * E-mail:
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Bendix L, Kølvraa S. [Telomeres and telomerase]. Ugeskr Laeger 2010; 172:2745-2748. [PMID: 20926043] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
In 2009 the Nobel Prize in Medicine was awarded to EH Blackburn, CW Greider and JW Szostak for their work on "How chromosomes are protected by telomeres and the enzyme telomerase". Telomeres are specialized DNA structures localized at the end of linear chromosomes. Telomeres are known as the biological clock of the cell, since they shorten with each cell division. Telomerase can elongate telomeres. Telomeres protect chromosome ends against being recognized as double stranded DNA breaks, and are thought to be a guard against cancer. It has furthermore been suggested that telomeres may play a role in aging and age-related diseases.
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Affiliation(s)
- Laila Bendix
- Dansk Center for Aldringsforskning (DARC), Denmark.
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Bendix L, Kølvraa S. [The role of telomeres in cancer]. Ugeskr Laeger 2010; 172:2748-2751. [PMID: 20926044] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
Telomeres are a double-edged sword when it comes to cancer. On one hand, telomeres limit the cells' ability to divide and thereby restrict the uninhibited growth seen in cancer. On the other hand, short telomeres can initiate the chromosome instability that characterizes cancer. Diseases with the combination of short telomeres and high cancer risk are seen, but until now the use of telomeres as predictors of cancer has, in general, been unsuccessful. Telomeres and telomerase play an important role in further cancer development. Researchers are trying to exploit this in the development of new cancer therapies.
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Affiliation(s)
- Laila Bendix
- Dansk Center for Aldringsforskning (DARC), Denmark.
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Bendix L, Kølvraa S. [The role of telomeres in aging-related disease]. Ugeskr Laeger 2010; 172:2752-2755. [PMID: 20926045] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
Telomeres are specialized DNA structures, protecting the ends of linear chromosomes. The association between telomeres and cellular aging is well-established, and it has been shown that there is a negative correlation between telomere length and chronological age for many types of human tissue. On the other hand, the association between telomere length and mortality is poor. Nevertheless, it has been suggested that telomeres may play a role in the development of many aging-related diseases. This has led to attempts to develop telomere-elongating treatment.
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Affiliation(s)
- Laila Bendix
- Dansk Center for Aldringsforskning (DARC), Denmark.
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Kouniavsky G, Zeiger MA. The role of telomeres and telomerase in endocrine tumors. Discov Med 2010; 10:340-347. [PMID: 21034675] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
The enzyme, telomerase, is a reverse transcriptase that synthesizes the telomeric ends of linear chromosomes and compensate for the shortened telomere, thereby immortalizing the cell. It is present at the blastocyst stage of embryological development, low or undetectable in most somatic cells, and activated in cancer. Because of its strong association with cancer cell immortalization and proliferation, numerous attempts have been made to capitalize on its diagnostic, prognostic, and therapeutic potential. Herein we discuss the role of telomerase in normal, benign, and cancerous endocrine tissues.
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Affiliation(s)
- Guennadi Kouniavsky
- Division of Endocrine Surgery, Department of Surgery, Johns Hopkins University School of Medicine, 600 North Wolfe Street, Baltimore, Maryland 21287, USA
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Roos G, Osterman P. [The Nobel Prize on the protective function of telomeres can be very useful clinically. Several research targets ahead--not only new cancer therapies]. Lakartidningen 2010; 107:190-193. [PMID: 20333974] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
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Hiraoka Y, Haraguchi T. [Mechanism of chromosome protection by telomere and telomerase]. Tanpakushitsu Kakusan Koso 2010; 55:104-107. [PMID: 20162857] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
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49
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Gancarcíková M, Zemanová Z, Brezinová J, Berková A, Vcelíková S, Smigová J, Michalová K. The role of telomeres and telomerase complex in haematological neoplasia: the length of telomeres as a marker of carcinogenesis and prognosis of disease. Prague Med Rep 2010; 111:91-105. [PMID: 20653999] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/29/2023] Open
Abstract
Human telomeres (discovery of telomere structure and function has been recently awarded The Nobel Prize) consist of approximately 5-12 kb of tandem repeated sequences (TTAGGG)n and associated proteins capping chromosome ends which prevent degradation, loss of genetic information, end-to-end fusion, senescence and apoptosis. Due to the end-replication problem, telomere repeats are lost with each cell division, eventually leading to genetic instability and cellular senescence when telomeres become critically short. Stabilization of the telomeric DNA through telomerase activation, unique reverse transcriptase, or activation of the alternative mechanism of telomere maintenance is essential if the cells are to survive and proliferate indefinitely. Telomerase is expressed during early development and remains fully active in specific germline cells, but is undetectable in most normal somatic cells. High level of telomerase activity is detected in almost 90% of human tumours and immortalized cell lines. The hematopoietic compartment may develop genetic instability as a consequence of telomere erosion, resulting in aplastic anaemia (AA) and increased risk of myelodysplastic syndrome (MDS) and acute myeloid leukaemia (AML). Genetic instability associated with telomere dysfunction (i.e. short telomeres) is an early event in carcinogenesis. The molecular cytogenetic method telomere/centromere fluorescence in situ hybridization (T/C-FISH) can be used to characterize the telomere length of hematopoietic cells. This review describes recent advances in the molecular characterization of telomere system, the regulation of telomerase activity in cancer pathogenesis and shows that the telomeric length could be a potential clinical marker of hematologic neoplasia and prognosis of disease.
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Affiliation(s)
- M Gancarcíková
- Charles University in Prague, First Faculty of Medicine and General University Hospital, Institute of Clinical Biochemistry and Laboratory Diagnostics, Center of Oncocytogenetics, Prague, Czech Republic.
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Brás A, Rueff J. Telomerase and reactive oxygen species: Comments on Saretzki, G., 2009. Telomerase, mitochondria and oxidative stress. Exp. Gerontol. 44, 485-492. Exp Gerontol 2009; 45:171-2. [PMID: 20005282 DOI: 10.1016/j.exger.2009.12.006] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2009] [Revised: 11/13/2009] [Accepted: 12/03/2009] [Indexed: 11/29/2022]
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